Prevalencia de portación nasal de Staphylococcus aureus sensible y resistente a la meticilina en candidatos a artroplastia total de cadera o rodilla / Prevalence of nasal carriage of methicillin-sensitive and methicillin-resistant Staphylococcus aureus in candidates for total hip or knee arthroplasty

INTRODUCIÓN Las infecciones perioperatorias en cirugía de reemplazo articular son fuente importante de morbimortalidad, así como de altos costos económicos y sociales, tanto para el paciente como para su entorno. La colonización preoperatoria por Staphylococcus aureus ha sido reconocida como un factor de riesgo importante para desarrollar una infección de sitio quirúrgico.El objetivo de este estudio es conocer la prevalencia de portación nasal de S. aureus, tanto sensible a la meticilina (SASM) como resistente a la meticilina (SARM), en pacientes candidatos a cirugía de reemplazo articular de cadera o rodilla. MATERIALES Y MÉTODOS Se realizó un estudio observacional de una cohorte retrospectiva de pacientes con indicación de artroplastia total de cadera (ATC) y rodilla (ATR) electiva por artrosis severa en un hospital público de Chile. Los pacientes fueron sometidos a tamizaje preoperatorio de portación, cultivándose muestras obtenidas mediante hisopado de ambas fosas nasales. Los datos del laboratorio fueron recopilados y presentados como porcentaje de portación de S. aureus. RESULTADOS Se estudiaron 303 pacientes consecutivos de ATC y 343 de ATR. En total, 483 de los 646 pacientes (74,7%) tuvieron estudio preoperatorio de portación nasal. Se identificaron 123 pacientes (25,4%) portadores de S. aureus, de los cuales sólo 2 (0,41%) casos correspondieron a SARM. CONCLUSIÓN La prevalencia de portación nasal de S. aureus obtenida fue de 25%, similar a lo reportado en otras series. La prevalencia de SARM (0.41%), sin embargo, estuvo bajo lo descrito en la literatura internacional (0,6­6%). Sería de utilidad, dada la alta prevalencia de portación descrita en nuestro trabajo y de acuerdo a evidencia publicada recientemente, realizar protocolos de descolonización universales, sin necesidad de realizar tamizaje preoperatorio.

INTRODUCTION Surgical-site infections in joint replacement surgery are an important source of morbidity and mortality that entail high economic and social burden both for the patient and their environment. Preoperative colonization by Staphylococcus aureus has been recognized as an important risk factor for the development of surgical-site infection. The aim of the present study is to determine the prevalence of nasal colonization by S. aureus, both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) in patients who are candidates for total replacement of the hip or knee joints. MATERIALS AND METHODS A retrospective observational study of a cohort of 646 patients with an indication to undergo total hip arthroplasty (THA) or total knee arthroplasty (TKA) due to severe osteoarthritis was performed in a Public Hospital in Chile. The patients were submitted to a preoperative screening for S. aureus carriage, and the culture samples were obtained by swabbing both nostrils. The laboratory data was collected and presented as a percentage of carriage. RESULTS We consecutively examined 303 THA and 343 TKA patients. A total of 483 of the 646 patients (74.7%) underwent a preoperative study of nasal carriage. We identified 123 (25.4%) S. aureus carriers, and only found 2 (0.41%) cases corresponding to MRSA. CONCLUSION We found a prevalence of nasal carriage of S. aureus of 25.4%, a rate similar to that reported in other series. The prevalence of MRSA (0.41%), however, was lower than that reported in the international literature (0.6­6%). Given the high prevalence of carriage described in our work and according to recently published data, it would be worthwhile to carry out universal decolonization protocols, without the need for preoperative screening.

Piomiositis, artritis séptica y osteomielitis aguda porStaphylococcus aureus meticilino resistente de la comunidad enpaciente pediátrico / Pyomyositis, septic arthritis and acute osteomyelitis due tocommunity methicillin-resistant Staphylococcus aureus in apediatric patient

Las infecciones osteoarticulares y musculoesqueléticas son patologías infecciosas relativamente infrecuentes en la infancia, afectando generalmente a varones y menores de 5 años. Países desarrollados reportan una incidencia anual de osteomielitis de 10 a 80/100.000 niños y de 4 casos/100.000 niños para artritis séptica. En países tropicales, la piomiositis tiene una incidencia de un caso por cada 2.000 habitantes. El Staphylococcus aureus es el principal agente causal. En la infancia la vía más común del legada del germen a la articulación es la hematógena. Hasta en un 30% de niños coexisten osteomielitis aguda y artritis séptica. Se presenta el caso de preescolar masculino de 3años, quien posterior a aplastamiento de miembro inferior izquierdo, presenta aumento de volumen, dolor y limitación para la marcha, asociándose 9 días después fiebre de 39.5°C,acudiendo al Hospital Universitario de Caracas. La anamnesis, evaluación clínica y estudios paraclínicos fueron sugestivos depiomiositis de muslo izquierdo, osteomielitis de fémur izquierdo y artritis séptica de rodilla izquierda. Se indica antibioticoterapiacon cobertura para Staphylococcus aureus (ciprofloxacina y clindamicina). Se realizó artrotomía evacuadora y limpieza quirúrgica de estructuras afectadas. El cultivo reportó Staphylococcus aureus sensible a ciprofloxacina, gentamicina, linezolid, rifampicina, trimetropin/sulfametoxazol; resistentea clindamicina, eritromicina, oxacilina, por lo que se omitióclindamicina y se indicó trimetropin/sulfametoxazol. Cumplió21 días de tratamiento intravenoso, observándose evolución satisfactoria por lo que se decidió egreso, dando continuidad con tratamiento vía oral por cuatro semanas y seguimiento interdisciplinario. El abordaje oportuno y adecuado de estas patologías disminuye el riesgo de desarrollar complicaciones(AU)

Osteoarticular and musculoskeletal infections are relatively rare infectious diseases in childhood, generally affecting men and children under 5 years of age. Developed countries report an annual incidence of osteomyelitis of 10 to 80 / 100,000 children and 4 cases / 100,000 children for septicarthritis. In tropical countries, pyomyositis has an incidence of one case for every 2,000 inhabitants. Staphylococcus aureusis the main causative agent. In childhood the most commonroute of arrival of the germ to the joint is hematogenous.Up to 30% of children coexist acute osteomyelitis and septic arthritis. We present the case of a 3-year-old male preschoolerwho, after crushing his left lower limb, presented an increasein volume, pain, and limited gait, and was associated witha fever of 39.5 ° C 9 days later, going to the University Hospital of Caracas. the anamnesis, clinical evaluation and paraclinical studies were suggestive of pyomyositis of the leftthigh, osteomyelitis of the left femur and septic arthritis of the left knee. Antibiotic therapy with coverage for Staphylococcus aureus (ciprofloxacin and clindamycin) is indicated. Evacuating arthrotomy and surgical cleaning of affected structures were performed. The culture reported Staphylococcus aureus sensitiveto ciprofloxacin, gentamicin, linezolid, rifampin, trimetropin /sulfamethoxazole; resistant to clindamycin, erythromycin,oxacillin, therefore clindamycin was omitted and trimetropin /sulfamethoxazole was indicated. He completed 21 days ofintravenous treatment, observing satisfactory evolution so hisdis charge was decided, continuing with oral treatment for four weeks and interdisciplinary follow-up. The timely and adequate approach to these pathologies reduces the risk of developing complications(AU)

Portación nasal, antibiotipo y genotipo de cepas de Staphylococcus aureus aisladas en estudiantes de Medicina y de Enfermería Campus San Felipe, Universidad de Valparaíso, Chile, durante el año 2017 / Nasal carriage, antibiotype and genotype of isolated Staphylococcus aureus from Medicine and Nursing students of Campus San Felipe, University of Valparaiso, Chile, during 2017

INTRODUCCIÓN. Staphylococcus aureus es parte de la microbiota nasal en 20-30% de la población general, colonización que constituye un reservorio para su transmisión, lo que es preocupante en cepas resistentes a meticilina (SARM). OBJETIVO: Determinar la prevalencia de S. aureus en estudiantes de Medicina y Enfermería del Campus San Felipe y caracterizar sus aislamientos. MATERIAL Y MÉTODOS: El 2017 se midió la portación nasal a 225 estudiantes, a las cepas aisladas se le analizó su antibiotipo por difusión en agar, la relación clonal por electroforesis de campo pulsado y MLST. En SARM se determinó el cassette SCCmec y gen de la leucocidina de Panton-Valentine. RESULTADOS: 61 estudiantes portaron S. aureus (27,1%) incluyendo dos cepas SARM (0,9%). Staphylococcus aureus mostró resistencia a penicilina (75%), eritromicina (14%) y clindamicina (10%), cloranfenicol (1,6%) y levofloxacina, oxacilina, cefoxitina (3,3%). Se diferenciaron diecinueve pulsotipos y el secuenciotipo coincidió con complejos clonales descritos a nivel mundial en portadores de S. aureus: CC30, CC8, CC97, CC15, CC22 y CC1. Las dos cepas SARM correspondieron con los clones chileno/cordobés y USA100NY/J, ambas del CC5. CONCLUSIÓN: La portación nasal de S. aureus y SARM en los estudiantes coincidió con la portación en la población general y las cepas sensibles a meticilina mostraron diversidad clonal y alta susceptibilidad antimicrobiana, exceptuando a penicilina.

BACKGROUND: Staphylococcus aureus is part of the nasal microbiota in 20-30% of the population. This colonization is also a reservoir for its dissemination, which is worrying in the case of strains with resistance to methicillin (MRSA). AIM: To determine S. aureus nasal carriage in nursing and medical students of San Felipe Campus and characterize theirs isolates. METHODS: During 2017, nasal swabs were taken from 225 students and seeded in salt manitol agar. Antibiotypes were determined by agar diffusion and the genetic clonality was assessed by PFGE and MLST in isolated S. aureus. SCCmec cassette and Panton-Valentine leukocidin gene (pvl) presence were determined in the MRSA isolates. RESULTS: 61 students carried S. aureus (27.1%) including two MRSA strains (0.9%). S. aureus showed resistance to penicillin (75%), erythromycin (14%) and clindamycin (10%), chloramphenicol (1.6%) and levofloxacin, oxacillin, cefoxitin (3.3%). Nineteen PFGE-types were differentiated, and their sequence-types coincided with main clonal complexes described in S. aureus carriers from different places worldwide: CC30, CC8, CC97, CC15, CC22 and CC1. MRSA strains belonged to CC5 and they corresponded to the Chilean/Cordobes and USA100NY/J clones. CONCLUSION: Nasal carriage of S. aureus and MRSA in students, coincided with the general population and sensitive-methicillin strains showed clonal diversity and high antimicrobial susceptibility except for penicillin.

Staphylococcus aureus sensible a meticilina, productor de leucocidina de Panton Valentine: a propósito de dos casos pediátricos de infección osteoarticular / Panton-Valentine leukocidin toxin associated methicillin-susceptible Staphylococcus aureus infection: a report of two pediatric cases

Resumen Staphylococcus aureus coloniza la nasofaringe en un tercio de los individuos sanos y además es causante de infecciones graves en pediatría, como endocarditis, neumonía e infecciones osteoarticulares. Posee varios mecanismos de virulencia, siendo la leucocidina de Panton Valentine (LPV) uno de ellos, una exotoxina que causa muerte celular. Su producción está comúnmente relacionada con Staphylococcus aureus resistente a meticilina (SARM) e infecciones pulmonares y musculo-esqueléticas graves. Sin embargo, la producción de LPV no es exclusiva de SARM. Se presentan dos casos clínicos de pacientes con infección por Staphylococcus aureus sensible a meticilina productora de esta exotoxina.

Abstract Staphylococcus aureus colonizes the nasopharynx in one third of healthy individuals and is also responsible for several infections in pediatrics such as endocarditis, pneumonia and osteoarticular infections. It has several virulence mechanisms, such as Panton Valentine leukocidin (PVL), which is an exotoxin that causes cell death. It is commonly related to methicillin-resistant Staphylococcus aureus (MRSA) and more serious pulmonary and musculoskeletal infections. However, PVL is not exclusive to MRSA. Two clinical cases of patients with infection by methicillin-sensitive Staphylococcus aureus producing this exotoxin are presented.

Sodium fluoroacetate poisoning: A case report / Intoxicación por fluoroacetato de sodio, un reporte de caso

Abstract Introduction: Sodium fluoroacetate, known as compound 1080, was discovered in Germany during the Second World War. It is usually used as a rodenticide, it is an odorless and tasteless substance, with a lethal dose in humans of 2 mg / kg that is why it was withdrawn from the market in some countries, including Colombia; however, it is obtained illegally. This substance has biochemical and physiological effects at the cellular level that alter the transport of citrate at the mitochondrial level, generating accumulation of lactic acid and alteration of the glucose use. The clinical manifestations are nonspecific since there is no any cardinal symptom. Therefore, its diagnosis is made due to high clinical suspicion associated with establishment of exposure to the compound in view of the difficulty to obtain paraclinical confirmation in a timely manner. Methods: We present a case report of intentional ingestion of sodium fluoroacetate in an adolescent that is associated with an infection added to the bloodstream by methicillin- sensitive Staphylococcus aureus (MSSA). The patient developed multiple complications that lead to support in the Intensive Care Unit (ICU) with a satisfactory outcome. In view of the lack of a specific antidote, she was treated with ethanol in order to increase the level of acetate; thus, offering an alternative substrate to the Krebs cycle. It is suggested that the ethanol offers benefits in the acute treatment of these patients. Results: The patient with sodium fluoroacetate poisoning and kidney failure received renal replacement therapy with a favorable evolution and survival at discharge from the intensive care unit of a third-level hospital in the city of Pereira, Risaralda, Colombia. Conclusions: Sodium fluoroacetate poisoning is relatively rare and can cause acute kidney injury and multi-organ failure with a high rate of complications and death. A case of self-inflicted poisoning that received a timely manner continuous renal replacement therapy with a favorable outcome in terms of ICU survival was presented.

Resumen Introducción: El fluoroacetato de sodio ⎯conocido como compuesto 1080⎯, fue descubierto en Alemania durante la segunda guerra mundial, suele ser utilizado como raticida y se caracteriza por ser una sustancia inodora e insabora. En humanos, una dosis de 2 a mg/kg es letal; debido a su toxicidad fue retirado del mercado en algunos países, incluyendo Colombia, no obstante, se consigue de forma ilegal. Esta sustancia tiene efectos bioquímicos y fisiológicos a nivel celular que altera el transporte del citrato a nivel mitocondrial, generando acumulación de ácido láctico y alteración en la utilización de la glucosa. Las manifestaciones clínicas son inespecíficas y no existe un síntoma cardinal. Por ende, su diagnóstico se realiza por alta sospecha clínica, asociado al establecimiento de la exposición al compuesto, ya que la confirmación paraclínica es difícil de realizar oportunamente. Métodos: Se presenta un reporte de caso de ingestión intencional en un adolescente, asociado con infección agregada al torrente sanguíneo por Estafilococos Aureos Meticilino Sensible (EAMS). El paciente desarrolló múltiples complicaciones y requirió asistencia en Unidad de Cuidados Intensivos (UCI) con desenlace satisfactorio. Ya que no se cuenta con antídoto específico , se le dio tratamiento con etanol para aumentar el nivel de acetato, ofreciendo así un sustrato alterno al ciclo de Krebm. Se estima que el etanol puede ofrecer beneficios en el tratamiento agudo de estos pacientes. Resultados: Paciente con intoxicación por fluoroacetato de sodio e insuficiencia renal, recibe terapia de reemplazo renal con un evolución favorable y supervivencia al alta de la Unidad de Cuidados Intensivos de un hospital de tercer nivel en la ciudad de Pereira, Risaralda, Colombia. Conclusiones: La intoxicación por fluoroacetato de sodio es relativamente poco frecuente y puede causar injuria renal aguda y falla multiorgánica con alta tasa de complicaciones y muerte. Se presentó un caso de intoxicación autoinfligida que recibió terapia de reemplazo renal continua temprana con un desenlace favorable en términos de supervivencia en la UCI.

Antibiotic resistance profile in intrahospital pediatric services at third level centers in Dominican Republic / Perfil de resistencia a antibióticos en servicios pediátricos intrahospitalarios en centros de tercer nivel en República Dominicana

Objectives: The Dominican Republic lacks reliable information on antimicrobial resistance (AMR), which would allow physicians to prescribe the best treatment for common infectious diseases. This study aimed to define the antimicrobial resistance profiles of the more common pathogens from pediatric services, where data is even more important due to the vulnerability of the population. Methods: We collected data from patients admitted in the pediatric unit of three third level hospitals in the city of Santiago de los Caballeros, Dominican Republic, showing positive bacterial cultures, during a period of two years. Results: Half of the Gram negative pathogens exhibited third generation cephalosporins (3GC) resistance, 17% were resistant to carbapenems. Serratia marcescens presented an exceptionally high proportion of resistance to 3GC (95.9%). Staphylococcus aureus showed elevated resistance to methicillin (58.4%) and even to clindamycin (35.8%). Conclusion: There are elevated levels of antimicrobial resistance among the Enterobacteriaceae family and the Staphylococcus genus isolated from the pediatric population. Necessary measures should be taken to tackle AMR in the country.

Objetivos: La República Dominicana carece de información confiable sobre las resistencias antimicrobianas en el país, lo que permitiría al personal médico prescribir los mejores tratamientos para infecciones comunes. El objetivo de este estudio es definir los perfiles de resistencia antimicrobiana de los patógenos más comunes en servicios pediátricos, donde esta información es esencial, debido a la vulnerabilidad de la población. Métodos: Se tomaron los datos de reportes microbiológicos con cultivo bacteriano positivo procedentes de pacientes admitidos en la unidad pediátrica de tres hospitales de tercer nivel en la ciudad de Santiago de los Caballeros, República Dominicana, durante un periodo de dos años. Resultados: La mitad de los patógenos Gram negativos mostraron resistencia a cefalosporinas de tercera generación (3GC), 17% eran resistentes a carbapenémicos. Serratia marcescens presentó una resistencia excepcionalmente elevada a 3GC (95.9%). Staphylococcus aureus mostró alta resistencia a meticilina (58.4%) e incluso a clindamicina (35.8%). Conclusión: Existen elevados niveles de resistencia antimicrobiana entre las enterobacterias y los estafilococos en la población pediátrica dominicana. Es necesario tomar medidas para abordar este problema en el país.

Comparación de métodos fenotípico y genotípico en la detección de Staphylococcus aureus meticilino resistente en centros hospitalarios de Pereira / Comparison between phenotype and genotype methods in the detection of Methicillin-Resistant Staphylococcus aureus in Center Hospital of Pereira

Resumen Introducción: Staphylococcus aureus es un importante patógeno, puede causar infecciones leves de piel, hasta enfermedades con compromiso vital. La aparición de Staphylococcus aureus meticilino-resistentes, MRSA; ha aumentado su resistencia antimicrobiana, especialmente a β-lactámicos; dificultando el manejo de las infecciones, aumentando las tasas de morbi-mortalidad, convirtiéndose en un problema de salud pública. La expresión fenotípica de la resistencia suele ser heterogénea, dificultando su detección en el laboratorio por métodos convencionales; lo cual, incrementa los costos en la atención hospitalaria de infecciones por MRSA. Objetivo: Comparar métodos fenotípico y genotípico para la identificación de aislamientos hospitalarios de MRSA en centros hospitalarios de Pereira. Métodos: A partir de aislamientos de S. aureus obtenidos de tres instituciones de salud de alta complejidad clasificadas como A, B y C; se determinó la resistencia a meticilina por concentración mínima inhibitoria en sistemas automatizados y el gen mecA por PCR múltiple. Resultados: La prevalencia fenotípica de MRSA fue 44,4%, la institución A presentó la mayor tasa con 48,65%. La prevalencia genotípica fue 57,4%; en las instituciones A, B y C fue 55,2%, 41,7% y 75%, respectivamente, con diferencia estadísticamente significativa (p<0.05). La sensibilidad y especificidad del método fenotípico fue 99,0% y 94,7%, respectivamente, frente al método gold estándar de la PCR. El índice Kappa fue 0,942 indicando un nivel de concordancia muy bueno entre métodos. Conclusión: La prevalencia de aislamientos MRSA en las instituciones de Pereira fue alta. Los índices de concordancia de los métodos fenotípicos demostraron que son confiables para el diagnóstico de infecciones por MRSA.

Abstract Introduction: Staphylococcus aureus is an important pathogen, can cause mild skin infections, to diseases with compromise vital. The appearance of Methicillin-Resistant Staphylococcus aureus MRSA; It has increased its antimicrobial resistance, especially to β-lactam; hampering the handling of them infections, increasing the rates of morbidity-mortality, becoming a health public problem. The phenotype expression of the resistance tend to be heterogeneous, hindering its detection in the laboratory by conventional methods; which increases costs in the hospital care of MRSA infections. Objective: To compare the phenotypes and genotypes methods for identification of hospital isolates MRSA in Pereira. Methods: From isolates of S. aureus obtained of three high complexity institutions of health classified as A, B and C; determined resistance to Methicillin by minimum inhibitory concentration in automated systems and mecA gene by multiplex PCR. Results: The phenotype prevalence of MRSA was 44.4%, the institution A presented the highest rate with 48.65%. The genotype prevalence was 57.4%; in the institutions A, B and C was 55.2%, 41.7% and 75%, respectively, with difference statistically significant (p < 0.05). The sensitivity and specificity of the phenotype method were 99.0% and 94.7%, respectively, against the gold standard of the PCR method. The Kappa index was 0,942 indicating a very good level of concordance between methods. Conclusion: The prevalence of isolates MRSA in the institutions of Pereira was high. The concordance index of phenotype methods showed that they are reliable for the diagnosis of MRSA infections.

Comparación de las características y curso clínico de la endocarditis infecciosa por Staphylococcus aureus meticilino sensible versus meticilino resistente / Characteristics and clinical course of endocarditis due to Methicillin-sensitive versus methicillin-resistant Staphylococcus aureus

Resumen Introducción: Staphylococcus aureus es uno de los agentes causales más comunes de la endocarditis infecciosa. Se reportan pocos estudios en Latinoamérica acerca de las diferencias entre los perfiles de resistencia a la meticilina. Objetivo: Describir las características y el curso clínico de los pacientes con S. aureus sensible a meticilina frente al resistente. Métodos: Estudio observacional retrospectivo, cohorte histórica de pacientes adultos con diagnóstico confirmado de endocarditis entre los años 2011 y 2015. Se seleccionaron pacientes positivos para S. aureus comparando las características y el curso clínico entre los casos S. aureus sensible a meticilina frente al resistente. Resultados: Se estudiaron 86 pacientes con endocarditis. 28 (33%) tenían infección por S. aureus. 21 (75%) tenían endocarditis por S. aureus sensible a meticilina y 7 (25%) por S. aureus resistente a meticilina. En el grupo S. aureus sensible a meticilina, 11 (52,3%) fueron infecciones asociadas a atención en salud. La mayoría de casos de S. aureus resistente a meticilina fueron (85,7%) adquiridos en comunidad. La mortalidad de endocarditis por S. aureus sensible a meticilina fue superior a la causada por el resistente (33,3% vs. 14%). Conclusiones: S. aureus sigue siendo el agente más frecuente en endocarditis, más comúnmente el sensible a la meticilina. Los eventos embólicos y la gravedad fueron mayores en S. aureus sensible a meticilina. La mayor proporción de endocarditis debido a S. aureus resistente a meticilina se adquirió en la comunidad, por lo que se sugiere iniciar cobertura empírica contra S. aureus resistente a meticilina en todo caso de endocarditis adquirida en la comunidad.

Abstract Introduction: Staphylococcus aureus is one of the most common sources of infectious endocarditis. There are few studies in Latin America that report on the differences between the methicillin resistance profiles. Objective: To describe the characteristics and clinical course of patients with methicillin-sensitive S. aureus (MSSA) compared to methicillin-resistance S. aureus (MRSA) Methods: An observational, retrospective study was conducted on a historical cohort of adult patients with a confirmed diagnosis of endocarditis between the years 2011 and 2015. Patients positive for S. aureus were selected and the characteristics and clinical course and the cases of MSSA were compared with those of MRSA. Results: A total of 86 patients with endocarditis were included, of whom 28 (33%) had an infection due to S. aureus, and 21 (75%) had endocarditis due to methicillin-sensitive S. aureus, and 7 (25%) due to MRSA. In the MSSA group, 11 (52.3%) were infections associated with health care. The majority (85.7%) of cases of MRSA were community acquired. The endocarditis mortality due to MSSA was higher than that caused by MRSA (33.3% vs. 14%). Conclusions: S. aureus continues to be the most common agent in endocarditis, with MSSA being more common. The embolic events and the severity were greater in MSSA. The majority of endocarditis due to MRSA is acquired in the community, and for this reason it is suggested starting empirical cover against MRSA in all cases of community acquired endocarditis.

Análisis MLVA y perfil de virulencia de aislamientos de Staphylococcus aureus resistentes a la meticilina adquiridos en la comunidad causantes de infecciones pediátricas en Paraguay

Staphylococcus aureus resistente a la meticilina adquirido en la comunidad (SARM-AC) es uno de los principales patógenos causantes de infecciones de piel y partes blandas, aunque también se lo implica en infecciones graves, como osteomielitis y neumonía. El objetivo de este estudio descriptivo fue determinar el tipo de cassette SCCmec, el perfil de virulencia y la variabilidad genética de 21 aislamientos de SARM-AC que infectaron a niños paraguayos en el año 2010. Se determinó por PCR el tipo de cassette SCCmec y los factores de virulencia, en tanto que la variabilidad genética se determinó por la técnica multiple locus variable analysis (MLVA). Todos los aislamientos (100%) presentaron cassette SCCmec IV; algunos portaron factores de virulencia como hla, hlb y sea (el 28,6, el 9,5 y el 4,8%, respectivamente). El análisis MLVA mostró gran variabilidad genética, con datos de antibiotipo y perfil de virulencia congruentes. Este trabajo pone de manifiesto por primera vez en Paraguay la presencia de SARM-AC portador del cassette SCCmec IV con elevada diversidad genética.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is one of the first causes of skin and soft tissue infections, and can also produce severe diseases such as osteomyelitis and pneumonia. The aim of this descriptive study was to determine the SCCmec type and virulence profile and to study the genetic diversity by MLVA analysis of 21 CA-MRSA isolates that infected Paraguayan children in 2010. The SCCmec type and virulence factors were performed by PCR and genetic diversity by MLVA (multiple locus variable analysis). All the isolates carried SCCmec cassette IV. hla, hlb and sea genes were detected in 28,6%, 9,5% and 4,8% respectively. The MLVA analysis showed high genetic diversity with congruent antibiotic resistance and virulence profiles. This study revealed the presence of CA-MRSA harbouring SCCmec IV with high genetic diversity, providing information not available in our country.

Caracterización fenotípica de cepas de Staphylococcus aureus productoras de ß-lactamasas y resistente a la meticilina / Phenotypic characterization of Staphylococcus aureus strains that produce ß-lactamases and are resistant to methicillin / Caracterização fenotípica de cepas de Staphylococcus aureus pro-dutoras de ß-lactamases e resistentes à meticilina

Introducción.Staphylococcus aureus resistente a la meticilina (SARM) es una bacteria Gram positiva que hace parte de la microbiota normal y es causa importante de infecciones de origen hospitalario o adquiridas en la comunidad.Objetivo. Caracterizar fenotípicamente los aislamientos de cepas de S. aureus productoras de ß-lacta-masas y resistentes a la meticilina (SARM), aisladas en infecciones asociadas con la atención en salud en un centro hospitalario de tercer nivel.Métodos. Se llevó a cabo un estudio observacional, descriptivo y de corte transversal, que incluyó 141 cepas aisladas de 1.761 muestras clínicas que presentaban crecimiento bacteriano, en una insti-tución de salud de II nivel de complejidad de Duitama (Boyacá). En la identificación bacteriana y en las pruebas de sensibilidad, se utilizó el método automatizado Phoenix 100™ Becton Dickinson (BD). Los fenotipos de resistencia por ß-lactamasas y a la meticilina se confirmaron siguiendo la metodología del Clinical and Laboratory Standards Institute del 2017.Resultados. De 1.761 muestras clínicas que presentaron crecimiento bacteriano, se obtuvieron 141 cepas de S. aureus, de las cuales 40 presentaron el fenotipo de resistencia por betalactamasas y 19 fueron resistentes a meticilina. Conclusión. Se revela una importante prevalencia de fenotipos de resistencia circulantes en Duitama (Boyacá), con mayor prevalencia de producción de betalactamasas y menor prevalencia del fenotipo resistente a meticilina (SARM). Esto corrobora que a nivel regional y en el municipio de Duitama, S. aureus es una importante causa de infección y constituye un problema de salud pública, el cual debe continuar siendo objeto de futuras investigaciones.

Introduction: Methicillin resistant Staphylococcus aureus (MRSA) is a Gram positive bacteria that is part of the normal flora and a major cause of infections related to medical care and associated with the community.Objective: To characterize phenotypically the resistance of S. aureus with ß-lactamases resistance and methicillin-resistant strains isolated in infections associated with health care in a tertiary hospital center.Materials and methods: An observational, descriptive cross-sectional study was carried out by analy-sis of 141 S. aureus isolates obtained from a III level health institution of Duitama (Boyacá). Bacterial identification and sensitivity tests were determined by the automated method Phoenix 100™ Becton Dickinson (BD). The phenotypes of resistance to ß-lactamases or methicillin were confirmed following the 2017methodology of the Clinical and Laboratory Standards Institute.Results: One hundred and forty-one S. aureus cultures were collected, of these 40 strains were de-termined with the resistance phenotype type ß-lactamases extended spectrum and 19 resistant to methicillin (MRSA). Conclusions: High prevalence of circulating resistance phenotypes is revealed in Duitama, with a higher prevalence of ß-lactamases and a lower prevalence of the methicillin-resistant S. aureus phe-notype (MRSA), that in the region and in the municipality Duitama is an important cause of infection and constitutes a public health problem, which should continue to be the subject of future research.

Introdução. Staphylococcus aureus resistente à meticilina (MRSA) é uma bactéria Gram-positiva que faz parte da microbiota normal e é uma causa importante de infecções de origem hospitalar ou ad-quiridas na comunidade.Objetivo. Caracterizar fenotipicamente isolados de cepas de S. aureus produtoras de ß-lactamases e resistentes à meticilina (MRSA), isolados em infecções relacionadas à assistência à saúde em um centro hospitalar de terceiro nível.Materiais e métodos. Foi realizado um estudo observacional, descritivo e transversal, que incluiu 141 cepas isoladas de 1.761 amostras clínicas que evidenciaram crescimento bacteriano, em uma ins-tituição de saúde do nível II de complexidade de Duitama (Boyacá). Na identificação bacteriana e nos testes de sensibilidade, foi utilizado o método automatizado Phoenix 100 ™ Becton Dickinson (BD). Os fenótipos de resistência para ß-lactamases e meticilina foram confirmados seguindo a metodologia do Clinical and Laboratory Standards Institute de 2017.Resultados. Das 1.761 amostras clínicas que apresentaram crescimento bacteriano, foram obtidas 141 cepas de S. aureus, das quais 40 tiveram o fenótipo de resistência às beta-lactamases e 19 resis-tiram à meticilina.Conclusão. Foi revelada uma importante prevalência de fenótipos de resistência circulante em Duitama (Boyacá), com maior prevalência de produção de beta-lactamases e menor prevalência do fenótipo resistente à meticilina (MRSA). Isso corrobora que, ao nível regional e no município de Duitama, S. aureus é uma importante causa de infecção e constitui um problema de saúde pública, que deve con-tinuar sendo objeto de pesquisas futuras.

Interaction study between vancomycin and liposomes containing natural compounds against methicillin-resistant Staphylococcus aureus clinical isolates

ABSTRACT The treatment of infections caused by resistant microorganisms is limited, and vancomycin (VAN) treatment failures for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia are not uncommon, even when MRSA clinical isolates are susceptible to VAN. Thus, this study proposed the association of VAN with usnic acid and ß-lapachone encapsulated into liposomes as a novel therapeutic option for infections caused by MRSA. Liposomes containing ß-lap (ß-lap-lipo) or usnic acid (UA-lipo) were prepared by the thin lipid film hydration method followed by sonication. Antimicrobial activity against MRSA clinical isolates was investigated by the microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). The interaction studies were carried out using the checkerboard method and epsilometer test (Etest). The interaction between VAN and ß-lap or ß-lap-lipo was synergistic (FICI = 0.453 and FICI = 0.358, respectively). An additive interaction between VAN and UA (FICI = 0.515) was found. UA-lipo resulted in synergism with VAN (FICI = 0.276). The Etest reproduced the results obtained by the checkerboard method for approximately 82% of the analysis. Thus, the present study demonstrated that VAN in combination with UA-lipo, ß-lap or ß-lap-lipo synergistically enhanced antibacterial activity against MRSA

Bases moleculares de la resistencia a meticilina en Staphylococcus aureus / Molecular basis of methicillin-resistance in Staphylococcus aureus

Resumen Desde el inicio de la era antimicrobiana se han ido seleccionando gradualmente cepas de Staphylococcus aureus resistentes a antimicrobianos de amplio uso clínico. Es así como en 1960 se describen en Inglaterra las primeras cepas resistentes a meticilina, y algunos años después son informadas en hospitales de Chile. Actualmente, S. aureus resistente a penicilinas antiestafilocóccicas es endémico en los hospitales de nuestro país y del mundo, siendo responsable de una alta morbimortalidad. La resistencia es mediada habitualmente por la síntesis de una nueva transpeptidasa, denominada PBP2a o PBP2' que posee menos afinidad por el β-lactámico, y es la que mantiene la síntesis de peptidoglicano en presencia del antimicrobiano. Esta nueva enzima se encuentra codificada en el gen mecA, a su vez inserto en un cassette cromosomal con estructura de isla genómica, de los cuales existen varios tipos y subtipos. La resistencia a meticilina se encuentra regulada, principalmente, por un mecanismo de inducción de la expresión del gen en presencia del β-lactámico, a través de un receptor de membrana y un represor de la expresión. Si bien se han descrito mecanismos generadores de resistencia a meticilina mec independientes, son categóricamente menos frecuentes.

Staphylococcus aureus isolates resistant to several antimicrobials have been gradually emerged since the beginning of the antibiotic era. Consequently, the first isolation of methicillin-resistant S. aureus occurred in 1960, which was described a few years later in Chile. Currently, S. aureus resistant to antistaphylococcal penicillins is endemic in Chilean hospitals and worldwide, being responsible for a high burden of morbidity and mortality. This resistance is mediated by the expression of a new transpeptidase, named PBP2a or PBP2', which possesses lower affinity for the β-lactam antibiotics, allowing the synthesis of peptidoglycan even in presence of these antimicrobial agents. This new enzyme is encoded by the mecA gene, itself embedded in a chromosomal cassette displaying a genomic island structure, of which there are several types and subtypes. Methicillin resistance is mainly regulated by an induction mechanism activated in the presence of β-lactams, through a membrane receptor and a repressor of the gene expression. Although mec-independent methicillin resistance mechanisms have been described, they are clearly infrequent.

Infección grave por Staphylococcus aureus meticilino sensible productor de leucocidina de Panton-Valentine: reportes de dos casos / Severe infection by methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin: reports of two cases

Staphylococcus aureus es uno de los principales agentes etiológicos de infecciones en niños provenientes de la comunidad y del ámbito hospitalario. La gravedad de estos cuadros se asocia a factores de virulencia, entre los que se encuentra la leucocidina de Panton-Valentine. Tanto Staphylococcus aureus resistente como sensible a la meticilina producen esta leucocidina, aunque con frecuencia variable. Presentamos a dos niños con infección grave por Staphylococcus aureus sensible a la meticilina productor de leucocidina de Panton-Valentine con complicaciones osteoarticulares y endovasculares. Es fundamental la sospecha diagnóstica, el tratamiento antibiótico adecuado y el manejo quirúrgico precoz para mejorar el abordaje de estas infecciones. Se debe mantener la vigilancia epidemiológica para detectar la frecuencia de las infecciones causadas por estas bacterias.

Staphylococcus aureus is a major etiologic agent of infections in children from the community and the hospital setting. The severity of these conditions is associated with virulence factors, including the Panton-Valentine leukocidin. Both methicillin resistant and sensitive Staphylococcus aureus produce this leukocidin although with varying frequency. We present two children with severe infection by sensitive Staphylococcus aureus producer of Panton-Valentine leukocidin with musculoskeletal and endovascular complications. It is essential the suspected diagnosis, appropriate antibiotic treatment and early surgical management to improve the approach of these infections. Epidemiological surveillance should be mantained to detect the frequency of infections caused by these bacteria.

Worrisome trends in rising minimum inhibitory concentration values of antibiotics against methicillin resistant Staphylococcus aureus - Insights from a tertiary care center, South India

ABSTRACT INTRODUCTION: Appearance of isolated reports of resistance to anti-methicillin-resistantStaphylococcus aureus (MRSA) drugs is worrisome underscoring the need to continuously monitor the susceptibility of clinical MRSA isolates to these drugs. Hence, the present study is conducted to determine the susceptibility of MRSA isolates to various classes of anti-MRSA drugs such as vancomycin (glycopeptide), daptomycin (lipopeptide), tigecycline (glycylcycline), and linezolid (oxazolidinone) to determine the MIC50 and MIC90 values, and to observe MIC creep over a three year period, if any, with respect to these drugs. METHODS: A total of 200 isolates of MRSA obtained from clinical specimens were included. MIC was determined by E-test for anti-MRSA antibiotics vancomycin, linezolid, daptomycin, and tigecycline. Non-parametric methods (Kruskal-Wallis and Chi-square test) were used to assess MIC trends over time. In addition, MIC50 and MIC90 values were also calculated. RESULTS: No isolate was found resistant to vancomycin, daptomycin, or linezolid; five isolates were resistant to tigecycline. Seven VISA isolates were encountered with the MIC value for vancomycin of 4 µg/mL. MIC values for vancomycin, tigecycline, linezolid showed a definite increase over a 3-year period which was statistically significant with p-values <0.0001, 0.0032, 0.0242, respectively. When the percentage of isolates with a median MIC value less than or equal to that of the index year was calculated, the change was most striking with vancomycin. The proportion of isolates with higher MIC values was greater in 2014 than 2012 and 2013. CONCLUSION: MIC creep was notably observed with vancomycin, and to some extent with tigecycline and linezolid. Selection pressure may result in creeping MICs, which may herald the emergence of resistant organisms.

Colonización y factores de virulencia de Staphylococcus aureus resistente a meticilina en una población infantil de Montería / Colonization and virulence factors of methicillin resistant Staphylococcus aureus in a pediatric population in Montería, Colombia / Colonização e fatores de virulência de Staphylococcus aureus resistente a meticilina numa população infantil de Montería

Introducción: Staphylococcus aureus resistente a meticilina (SARM) puede colonizar el cuerpo humano, con mayor frecuencia en las fosas nasales, pero también en las manos, el periné y la faringe. Además, se ha propuesto que la colonización puede ser un factor de riesgo para adquirir infecciones futuras. Objetivo: determinar la prevalencia y las características microbiológicas y moleculares del SARM en una población infantil sana. Metodología: se hizo un estudio descriptivo transversal para determinar la tasa de colonización nasal por SARM en 150 niños pertenecientes a 13 hogares infantiles de la ciudad de Montería. Los aislamientos se hicieron a partir de hisopados nasales y faríngeos, se identificaron mediante pruebas microbiológicas convencionales y se confirmaron y caracterizaron por métodos moleculares. Resultados: la tasa de colonización por SARM fue del 9,3% (14/150). El 62,5% de los aislamientos portaban el SCCmec subtipo IVc; 87,5% de los aislamientos presentaron los genes que codifican para PVL y Sek, mientras que 81,2% portaban el gen bsaB. Conclusión: el porcentaje de colonización hallado es uno de los más altos reportados para la población infantil de la región Caribe colombiana, y los aislamientos presentaron factores de virulencia relacionados con cuadros clínicos agresivos.

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is able to colonize the human body, most frequently the nostrils, but also the hands, perineum and throat. Such colonization has been proposed as a risk factor to acquire future infections. Objective: To determine the prevalence, and the microbiological and molecular characteristics of MRSA in healthy children. Methodology: A cross-sectional descriptive study was done of 150 children from 13 day care centers in Montería, Colombia. Nasal and throat swabs were obtained. The isolates were identified and characterized by microbiological and molecular methods. Results: The MRSA colonization rate was 9.3% (14/150). 62.5% of the isolates carried the subtype IVc of SCCmec, and 87.5% had the genes encoding for PVL and Sek, while 81.2% carried the gene bsaB. Conclusion: The percentage of colonization found is one of the highest reported among children from the Colombian Caribbean region, and the isolates have virulence factors that have been associated with an aggressive clinical course.

Introdução: Staphylococcus aureus resistente a meticilina (SARM) pode colonizar o corpo humano, com maior frequência nas fossas nasais, mas também nas mãos, o períneo e a faringe. Ademais, propôs-se do que a colonização pode ser um fator de risco para adquirir infecções futuras. Objetivo: determinar a prevalência e as características microbiológicas e moleculares do SARM numa população infantil sã. Metodologia: fez-se um estudo descritivo transversal para determinar a taxa de colonização nasal por SARM em 150 crianças pertencentes a 13 lares infantis da cidade de Montería. Os isolamentos se fizeram a partir de amostras com suabe nasais e faríngeos, identificaram-se mediante provas microbiológicas convencionais e se confirmaram e caracterizaram por métodos moleculares. Resultados: a taxa de colonização por SARM foi de 9,3 % (14/150). 62,5% dos isolamentos portavam o SCCmec subtipo IVc; 87,5% dos isolamentos apresentaram os genes que codificam para PVL e Sek, enquanto 81,2% portavam o gene bsaB. Conclusão: a porcentagem de colonização achado é um dos mais altos reportados para a população infantil da região Caribe colombiana, e os isolamentos apresentaram fatores de virulência relacionados com quadros clínicos agressivos.

Tendência de resistência entre isolados clínicos de Staphylococcus aureus em um hospital universitário do norte do Paraná de 2002 a 2011 / Trends in antimicrobial resistance among clinical isolates of Staphylococcus aureus in a university hospital of the north of Paraná from 2002 through 2011

Staphylococcus aureus são patógenos com alta ocorrência em infecções hospitalares e comunitárias e têm grande capacidade de adquirir resistência. O objetivo deste estudo foi determinar o perfil de resistência aos antimicrobianos de S. aureus isolados no Hospital Universitário de Londrina de janeiro de 2002 a dezembro de 2011. A análise retrospectiva de 3.494 S. aureus foi realizada a partir de um banco de dados do setor de Microbiologia do Laboratório Clínico do Hospital Universitário de Londrina (HUL). Resistência aos antimicrobianos foi determinada de acordo com os critérios recomendados pelo Clinical Laboratory Standard Institute (CLSI-2011). Os maiores percentuais de resistência foram verificados para eritromicina (49,4%), oxacilina, clindamicina (41,8%) e ciprofloxacina (36,5%). Adicionalmente, ocorreu redução significativa nas taxas de resistência à gentamicina, e a sulfametoxazol-trimetoprim. Todas as cepas analisadas foram sensíveis à linezolide. Verificou-se que 40% apresentaram susceptibilidade reduzida à vancomicina. Estes dados revelaram uma provável mudança na epidemiologia de S. aureus na nossa região, o que pode trazer impacto no tratamento e controle da infecção por este agente etiológico.

Staphylococcus aureus are pathogens with high incidence of nosocomial infections and community and has great ability to acquire resistance. The objective of this study was to determine susceptibility to antimicrobial profiles of S. aureus isolated in Londrina University Hospital, from January 2002 through December 2011. The retrospective analysis of 3,494 S. aureus performed from a database of Clinical Laboratory Microbiology HU sector. Antibiotic resistance was judged according to the criteria recommended by the Clinical Laboratory Standards Institute. The highest percentages of resistance was founding to erythromycin (49.4%), clindamycin and oxacillin (41.8%) and ciprofloxacin (36.5%). In addition, there was a significant reduction in gentamicin resistance rates, and trimethoprim-sulfamethoxazol. All strains studied were susceptible to linezolid. We found that 40% showed reduced susceptibility to vancomycin. These data indicate a possible change in the epidemiology of S. aureus in our region, which can bring impact on the treatment and control of infection by this agent.

Causa infrecuente de encefalitis por Staphylococcus aureus, reporte de un caso / Infrequent cause of encephalitis by Staphylococcus aureus

Se presenta un caso de encefalitis por Staphylococcus aureus meticilino sensible. Se trata de una paciente de sexo femenino, de 20 años de edad, quien fue atendida en la Fundación Centro Colombiano de Epilepsia y Enfermedades Neurológicas, de Cartagena, por presentar cefalea, progresivo deterioro del estado cognitivo y focalidad neurológica súbita con limitación a la emisión del lenguaje. Hallazgos en cultivo de LCR revelan crecimiento de Staphylococcus aureus meticilino sensible. La evolución de esta paciente fue satisfactoria. Se hace una revisión del caso, se realiza análisis de infrecuencia de encefalitis por Staphylococcusa ureus meticilino sensible sin foco de infección primario establecido.

A case of encephalitis Staphylococcus aureusmethicillin sensitive is presented. This is a female patient of 20 years old, who was treated at ColombianFoundation Center for Epilepsy and Neurological Diseases, in Cartagena. Her symptoms were headaches, progressive deterioration of cognitive status, and sudden neurological deficit with limitation on the issuance of language. CSF culture findings reveal growth of S. aureusmethicillin sensitive. The evolution of this patient was satisfactory. A review of the case is made, analysis infrequency of encephalitis is carried by Staphylococcus aureus methicillin sensitive in primary, focus of infection established.

Staphylococcus aureus meticilino resistente comunitario, Hospital de Niños Baca Ortiz / Community methicilin-resistant Staphylococcus aureus; Baca Ortiz Children´s Hospital

Introducción: las infecciones debidas a Staphylococcus aureus adquiridos en la comunidad (MRSA-AC) están aumentando significativamente a nivel mundial. Su virulencia se caracteriza principalmente por la presencia de la leucocidina Panton- Valentine. Caso: en la siguiente revisión presentamos dos casos clínicos en niños ecuatorianos que tuvieron cuadros infecciosos con las características de MRSA-AC con el objetivo de analizar la importancia del estudio de sensibilidad de los antibióticos para S. aureus adquiridas en la comunidad, lo que determina un manejo adecuado y temprano en la terapéutica de estas infecciones.

Introduction: infections due to community-acquired Staphylococcus aureus (MRSA -AC) are increasing signifcantly worldwide. Its virulence is mainly characterized by the presence of Panton- Valentine Leukocidin. This study pretends to analyze the importance of studying antibiotic sensitivity of community- acquired S. aureus, which determines appropriate management and early treatment of these infections. Case study: we present two cases in Ecuadorian children who had the characteristics of MRSA-AC.

In vitro susceptibility to methicillin, vancomycin and linezolid of staphylococci isolated from bloodstream infections in eastern Turkey

Staphylococcus species are one of the major causes of bacterial bloodstream infections. Multi-resistant staphylococci infections are major therapeutic problems. This study was aimed to detect methicillin, linezolid and vancomycin susceptibilities of Staphylococcus isolates. A total of 870 Staphylococcus strains isolated from blood cultures of hospitalized patients with BSI. Antimicrobial susceptibilities of methicillin, linezolid and vancomycin were detected according to the Clinical and Laboratory Standards Institute (CLSI). A total of 771 (88.6%) isolates were coagulase-negative staphylococci (CoNS). 700 (80.5%) isolates were methicillin-resistant (MR) and 170 (19.5%) were methicillin-susceptible (MS). All the MS isolates were also susceptible to linezolid. However 15 (1.7%) of MR strains were resistant to linezolid. The minimum inhibitory concentration range for the linezolid-resistant isolates by Etest was 6-32 µg/mL. The difference between linezolid susceptibilities for MS and MR staphylococci was not quite statistically significant (p = 0.052). There was no statistically significant difference between S. aureus and CoNS isolates for linezolid susceptibility. All of the isolates were susceptible to vancomycin. In conclusion, linezolid is currently an efficient option for the treatment of methicillin-resistant staphylococci infections.

Implementation of vancomycin dosing nomogram in an electronic prescribing system: an innovative tool in antibiotic stewardship

Vancomycin (VAN) is the gold standard therapy for Methicillin-resistant Staphylococcus aureus (MRSA) infections such as bacteremia and endocarditis. However, VAN suboptimal dosing for serious infections caused by S. aureus isolates that have elevated minimum inhibitory concentration (MIC), could be associated with poor outcome. Better understanding of VAN pharmacokinetics and pharmacodynamics (PK/PD) has led to the creation of new recommendations with optimized dosing regimens for the treatment of MRSA infections. For severe infectious, such as pneumonia and endocarditis, a VAN serum trough concentration of 15-20 mg/L at the steady state should be targeted. The aim of this study was to show how a nomogram with updated VAN dosing was devised and how it was implemented in the electronic prescribing (e-prescribing) system of a teaching hospital. VAN loading dose and maintenance doses were calculated from a pharmacokinetic equation using basic parameters: weight, estimated creatinine clearance, as well as peak and trough serum concentrations. The implementation of the VAN dosing nomogram in the hospital e-prescribing system definitively changed the long-standing medical prescription fallacy of "same dose fits all". Finally, this computer-based electronic program has allowed a wide-ranging intervention and should be recognized as a powerful tool for implementation in antimicrobial stewardship programs.

Vancomicina (VAN) é utilizada como primeira escolha na terapia de infecções causadas por Staphylococcus aureus resistentes à meticilina (MRSA), como bacteremia e endocardite. Entretanto, o aumento na concentração inibitória mínima (CIM) de isolados de S. aureus e doses subterapêuticas de VAN podem estar associados à falha terapêutica. Para o melhor entendimento sobre o perfil farmacocinético e farmacodinâmico (PK/PD) da VAN foram elaboradas novas recomendações para terapia de infecções causadas por MRSA. Para terapia de infecções graves, como pneumonia e endocardite, a concentração sérica do vale de VAN de 15-20 mg/L no estado de equilíbrio dinâmico deve ser o alvo. O objetivo do estudo foi desenvolver um nomograma com doses atualizadas de VAN e demonstrar como ele foi implementado no sistema de prescrição eletrônica em um Hospital Universitário. As doses de ataque e manutenção foram calculadas a partir de equações farmacocinéticas, utilizando parâmetros fundamentais: peso, depuração de creatinina, concentrações séricas do pico e do vale. A implementação de um nomograma de doses de VAN em um sistema de prescrição eletrônica modificou definitivamente o inadequado hábito de que "a mesma dose cabe em todos". Finalmente, esta abrangente ferramenta tecnológica deve ser considerada como uma robusta estratégia num programa de uso racional de antibióticos.