Características clínicas y microbiológicas de infecciones de piel y partes blandas en pacientes pediátricos de dos hospitales de Buenos Aires / Skin and soft tissue infections in pediatrics

Las infecciones de piel y partes blandas (IPPB) en niños son una de las principales causas de prescripción de antimicrobianos. El objetivo del estudio fue describir las características clínicas y microbiológicas de las IPPB ambulatorias de niños asistidos en dos hospitales zonales. Se realizó un estudio prospectivo entre el 1/11/2017 y el 1/11/2018. Se incluyeron pacientes entre 1 mes y 15 años internados en dos hospitales. Se evaluó: edad, sexo, localidad, factores predisponentes, tipo de IPPB, muestras biológicas realizadas, aislamiento microbiológico, tratamiento empírico indicado y evolución del cuadro. Se realizó antibiograma y determinación genética. Se calculó chi2, IC95, OR; α=5%. N= 94. 58,7% masculinos. 12 pacientes <1 año, 85 >1 año (promedio de edad 4 años, 1-15). El 36% de Tandil y 63,8% de Florencio Varela. El 59,6% corresponden a IPPB purulentas. Se aislaron microorganismos en un 59,6%. Los aislamientos principales: SAMR (40,4%), SAMS (7,4%), S. agalactiae (2,1%) y S. pyogenes (2,1%). El 100% de SAMR son portadores de gen mecA y SCCmec tipo IV, sin multirresistencia. No hubo diferencia estadística entre los factores de riesgo evaluados para el desarrollo de IPPB por SAMR. El 52,1% de los niños recibió tratamiento antibiótico combinado, siendo la más indicada TMS-SMX + CLI en 36 eventos. (38,3%). La evolución fue favorable: no hubo diferencia significativa entre el subgrupo que se aisló SAMR y el que no se aisló SAMR; 91,9% (34/37) y 92,6% (50/54) correspondientemente (chi2: 0,01; p= 0,97 IC95: 0,26-3,88). El principal agente etiológico fue SAMRco, debiendo adecuar los tratamientos a este microorganismo.

Skin and soft tissue infections (SSIs) in children are one of the main causes of antimicrobial prescription. The aim of the study was to describe the clinical and microbiological characteristics of outpatient SSIs in children attended in two hospitals. A prospective study was conducted between 11/1/2017 and 11/1/2018. Patients between 1 month and 15 years old, hospitalized were included. We evaluated: age, sex, locality, predisposing factors, type of IPPB, biological samples taken, microbiological isolation, empirical treatment indicated and evolution of the condition. An antibiogram and genetic determination were performed. Chi2, CI95, OR; α=5% were calculated. N= 94. 58.7% male. 12 patients <1 year, 85 >1 year (mean age 4 years, 1-15). 36% were from Tandil and 63.8% from Florencio Varela. 59.6% corresponded to purulent SSIs. The diagnostic yield was 59.6%. Main isolates: MRSA (40.4%), MSSA (7.4%), S. agalactiae (2.1%) and S. pyogenes (2.1%). 100% of MRSA carried the mecA gene and SCCmec type IV, with no multidrug resistance. There was no statistical difference between the risk factors evaluated. 52.1% of children received combined antibiotic treatment, the most indicated being TMS-SMX + CLI in 36 events. (38,3%). Evolution was favorable: there was no significant difference between the subgroup that isolated MRSA and the subgroup that did not isolate MRSA; 91.9% (34/37) and 92.6% (50/54) respectively (chi2: 0.01; p= 0.97 CI95: 0.26-3.88). The main etiological agent was MRSA, and treatments should be adapted to this microorganism

Infección necrotizante de tejidos blandos: experiencia durante 15 años en un hospital pediátrico / Necrotizing soft tissue infections: experience over 15 years in a pediatric hospital

INTRODUCCIÓN: La Infección Necrotizante de tejidos blandos (INTB) tiene una elevada morbimortalidad. El objetivo de este trabajo es describir del manejo perioperatorio de menores de 15 años que cursaron con INTB durante 15 años en un Hospital pediátrico. MATERIAL Y MÉTODOS: serie de pacientes identificados INTB entre 2000 y 2015 en el Hospital Roberto del Río. Se describen variables demográficas, clínicas, vacuna, tratamiento, cirugías, complicaciones, microorganismos, seguimiento, y fallecimientos. RESULTADOS: 22 pacientes, con mediana de 2 años y 9 meses de edad. 50% estaban cursando con una varicela. Dos fallecieron. Ninguno era previamente vacunado contra el virus varicela zoster. La localización fue tronco (14), extremidades (7), cuello (1). Los pacientes conscientes presentaron hiperestesia cutánea. Se realizó aseo quirúrgico con una mediana de 6,8 horas desde el inicio de la hiperestesia y 2 horas desde la sospecha diagnóstica. Los microorganismos fueron: S. pyogenes (38%) y E. coli (31%). Los antibióticos más frecuentes fueron penicilina más clindamicina. La herida se manejó con cierre primario, injertos y/o colgajos. Cinco evolucionaron con secuelas que necesitaron tratamiento. CONCLUSIÓN: Se identificó que la INTB puede presentarse con varicela. Debe sospecharse en lesiones cutáneas e hiperestesia desproporcionada. Resección amplia y precoz son fundamentales para el tratamiento.

INTRODUCTION: Necrotizing soft tissue infection (NSTI) has a high morbidity and mortality. The objective of this study is to describe the perioperative management of children under 15 years of age who have had this condition for 15 years in a pediatric hospital. MATERIAL AND METHODS: cases series of patients identified by Pathological Anatomy with NSTI during 2000 and 2015 at the Dr. Roberto del Río Hospital. Demographic variables, treatment, antecedents of vaccination, surgeries, complications, microorganisms, follow-up, and deaths are described. RESULTS: 22 patients were identified, with a median of 2 years 9 months of age (interquartile range: 13 months to 5 years y 10 months). 50% of the cases were associated to chickenpox. Two died. No patient was previously vaccinated against varicella zoster virus. The location was trunk (14), extremities (7) and neck (1). All conscious patients presented cutaneous hyperesthesia. Surgical debridement was performed with a median of 6.8 hours from the onset of hyperesthesia and 2 hours from diagnostic suspicion. The most frequent microorganisms were: Streptococcus pyogenes (38%) and Escherichia coli (31%). The most frequent antibiotics used were penicillin plus clindamycin. The wound was handled with primary closure, grafts and / or flaps. Five patients evolved with sequelae that needed treatment. CONCLUSION: It was identified that STNI in children is associated with chickenpox. It should be suspected in cutaneous lesions and disproportionate hyperesthesia. Aggressive resection is essential for treatment

High frequency of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in children under 1 year old with skin and soft tissue infections / Alta frequência de S. aureus (MSSA-MRSA) em crianças com menos de um ano deidade com infecções de pele e do tecido mole

Abstract Objective: Staphylococcus aureus is responsible for a large number of infections in pediatric population; however, information about the behavior of such infections in this population is limited. The aim of the study was to describe the clinical, epidemiological, and molecular characteristics of infections caused by methicillin-susceptible and resistant S. aureus (MSSA-MRSA) in a pediatric population. Method: A cross-sectional descriptive study in patients from birth to 14 years of age from three high-complexity institutions was conducted (2008-2010). All patients infected with methicillin-resistant S. aureus and a representative sample of patients infected with methicillin-susceptible S. aureus were included. Clinical and epidemiological information was obtained from medical records and molecular characterization included spa typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). In addition, staphylococcal cassette chromosome mec (SCCmec) and virulence factor genes were detected. Results: A total of 182 patients, 65 with methicillin-susceptible S. aureus infections and 117 with methicillin-resistant S. aureus infections, were included in the study; 41.4% of the patients being under 1 year. The most frequent infections were of the skin and soft tissues. Backgrounds such as having stayed in day care centers and previous use of antibiotics were more common in patients with methicillin-resistant S. aureus infections (p ≤ 0.05). Sixteen clonal complexes were identified and methicillin-susceptible S. aureus strains were more diverse. The most common cassette was staphylococcal cassette chromosomemec IVc (70.8%), which was linked to Panton-Valentine leukocidin (pvl). Conclusions: In contrast with other locations, a prevalence of infections in children under 1 year of age in the city could be observed; this emphasizes the importance of epidemiological knowledge at the local level.

Resumo Objetivo: O Staphylococcus aureus é responsável por um grande número de infecções na população pediátrica; contudo, as informações sobre o comportamento dessas infecções nessa população são limitadas. O objetivo do estudo foi descrever as características clínicas, epidemiológicas e moleculares de infecções causadas por Staphylococcus aureus suscetíveis e resistentes à meticilina (MSSA-MSRA) em uma população pediátrica. Método: Um estudo transversal descritivo foi realizado em pacientes entre 0 e 14 anos de idade de três instituições de alta complexidade (2008-2010). Todos os pacientes infectados com S. aureus resistentes à meticilina e uma amostra representativa de pacientes infectados com S. aureus suscetíveis à meticilina foram incluídos. As informações clínicas e epidemiológicas foram obtidas de prontuários médicos, e a caracterização molecular incluiu tipagem spa, Eletroforese em Gel de Campo Pulsado (PFGE) e Tipagem de sequências multilocus (MLST). Além disso, o Cassete Cromossômico Estafilocócico mec (SCCmec) e genes de fatores de virulência foram detectados. Resultados: 182 pacientes, 65 com infecções por S. aureus suscetíveis à meticilina e 117 com infecções por S. aureus resistentes à meticilina, foram incluídos no estudo; 41,4% dos pacientes com menos de um ano de idade. As infecções mais frequentes foram da pele e dos tecidos moles. Os históricos como internações em centros de atendimento e o uso prévio de antibióticos foram mais comuns em pacientes com infecções por S. aureus resistentes à meticilina (p ≤ 0,05). Dezesseis complexos clonais foram identificados, e as cepas de S. aureus suscetíveis à meticilina foram mais diversificadas. O cassete mais comum foi o Cassete Cromossômico Estafilocócicomec IVc (70,8%), relacionado à leucocidina de panton-valentine (pvl). Conclusões: Em comparação a outros locais, observamos uma prevalência de infecções em crianças com menos de um ano de idade na cidade; o que enfatiza a importância de conhecer a epidemiologia em nível local.

Características clínicas y microbiológicas de las infecciones de piel y tejidos blandos por Staphylococcus aureus en niños de un hospital en Medellín durante los años 2013 a 2015 / Clinical and microbiological characteristics of skin and soft tissue infections caused by Staphylococcus aureus in children in a hospital in Medellin from 2013 to 2015

Resumen Introducción: El principal microorganismo implicado en las infecciones de piel y tejidos blandos (IPTB) es Staphylococcus aureus, con incremento en las cepas resistentes a meticilina en los últimos años. Objetivo: Identificar la frecuencia de S. aureus resistente a meticilina (SARM) en IPTB en niños que consultaron a un hospital de cuarto nivel en la ciudad de Medellín. Métodos: Estudio descriptivo, retrospectivo, a partir de la revisión de historias clínicas. Se incluyeron pacientes menores de 18 años con IPTB causadas por S. aureus que no cumplieran con criterios de enfermedad invasora. Resultados: La prevalencia de SARM en esta población fue de 31%. El principal diagnóstico fue absceso cutáneo (68%), seguido por infección de sitio quirúrgico (15%) y celulitis no purulenta (6%). Tenían alguna co-morbilidad 85% de los pacientes. Todos los aislados fueron sensibles a rifampicina y cotrimoxazol. Ocho por ciento de los aislados fueron resistentes a clindamicina. Se encontró mayor prevalencia de SARM en lactantes comparado con los mayores de 2 años (60 vs 23%, p = 0,0109). Conclusión: Ante la alta prevalencia de SARM en IPTB se recomienda incluir en el tratamiento empírico antimicrobianos con cobertura para estas cepas, principalmente para lactantes.

Background: Skin and soft tissue infections (SSTI) are very common in children and Staphylococcus aureus is the main agent, with an increase of methicillin resistant strains (MRSA) in recent years. Aim: To identify the frequency of MRSA in skin and soft tissue infections (SSTI) in children from a high complex hospital in Medellin, Colombia. Methods: This is a descriptive, retrospective study, information was obtained from medical records. We included patients younger than 18 years with SSTI due to S. aureus who did not meet criteria for invasive disease. Results: The prevalence of MRSA in this population was 31%. The main diagnosis was cutaneous abscess (68%), followed by surgical site infection (15%) and non-purulent cellulitis (6%). Eighty five percent of the patients had at least 1 comorbidity. All isolates were sensitive to rifampicin and cotrimoxazole and 8% of the isolates were resistant to clindamycin. There was a higher prevalence of MRSA in patients under 2 years compared to older (60 vs 23%, p = 0,0109). Conclusion: In view of the high prevalence of MRSA in SSTI, empirical treatment with adequate coverage for MRSA is recommended, especially for patients under 2 years of age.

In vitro susceptibility of methicillin-resistant Staphylococcus aureus isolates from skin and soft tissue infections to vancomycin, daptomycin, linezolid and tedizolid

Abstract Introduction Treatment of multidrug-resistant Gram-positive infections caused by Staphylococcus aureus remains as a clinical challenge due to emergence of new resistance mechanisms. Tedizolid is a next-generation oxazolidinone, recently approved for skin and soft tissues infections. We conducted a study to determine in vitro susceptibility to vancomycin, daptomycin, linezolid and tedizolid in MRSA clinical isolates from adult patients with skin and soft tissue infections. Material and methods Methicillin-resistant S. aureus isolates were collected in three tertiary-care hospitals of Medellin, Colombia, from February 2008 to June 2010 as part of a previous study. Clinical characteristics were assessed by medical records and MIC values were determined by Epsilometer test. Genotypic analysis included spa typing, MLST, and SCCmec typing. Results A total of 150 MRSA isolates were evaluated and tedizolid MIC values obtained showed higher in vitro activity than other antimicrobials, with MIC values ranging from 0.13 µg/mL to 0.75 µg/mL and lower values of MIC50 and MIC90 (0.38 µg/mL and 0.5 µg/mL). In contrast, vancomycin and linezolid had higher MIC values, which ranged from 0.5 µg/mL to 2.0 µg/mL and from 0.38 µg/mL to 4.0 µg/mL, respectively. Tedizolid MICs were 2- to 5-fold lower than those of linezolid. Clinical characteristics showed high previous antimicrobial use and hospitalization history. The majority of the strains belong to the CC8 harboring the SCCmec IVc and were associated with the spa t1610 (29.33%, n = 44). Conclusion In vitro effectiveness of tedizolid was superior for isolates from skin and soft tissue infections in comparison with the other antibiotics evaluated. The above added to its less toxicity, good bioavailability, daily dose and unnecessity of dosage adjustment, make tedizolid in a promising alternative for the treatment of infections caused by MRSA.

Activity of ceftaroline and comparators against pathogens isolated from skin and soft tissue infections in Latin America - results of AWARE surveillance 2012

ABSTRACT As part of the Assessing Worldwide Antimicrobial Resistance Evaluation (AWARE) surveillance program in 2012 the in vitro activity of ceftaroline and relevant comparator antimicrobials was evaluated in six Latin American countries (Argentina, Brazil, Chile, Colombia, Mexico and Venezuela) against pathogens isolated from patients with hospital associated skin and soft tissue infections (SSTIs). The study documented that ceftaroline was highly active (MIC90 0.25 mg/L/% susceptible 100%) against methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus (MIC90 2 mg/L/% susceptible 83.3%) and ß-hemolytic streptococci (MIC90 0.008-0.015 mg/L/% susceptible 100%). The activity of ceftaroline against selected species of Enterobacteriaceae was dependent upon the presence or absence of extended-spectrum ß-lactamases (ESBLs). Against ESBL screen-negativeEscherichia coli, Klebsiella pneumoniae, andKlebsiella oxytoca the MIC90 and percent susceptible for ceftaroline were (0.5 mg/L/94.1%), (0.5 mg/L/99.0%) and (0.5 mg/L/91.5%), respectively. Ceftaroline demonstrated potent activity against a recent collection of pathogens associated with SSTI in six Latin American countries in 2012.

Antimicrobial susceptibility, virulence determinant carriage and molecular characteristics of Staphylococcus aureus isolates associated with skin and soft tissue infections

ABSTRACT A better understanding of the antimicrobial susceptibility, carriage of virulence determinants and molecular characteristics of Staphylococcus aureus isolates associated with skin and soft tissue infections (SSTIs) may provide further insights related to clinical outcomes with these infections. From January 2012 to September 2013, a total of 128 non-duplicateS. aureus isolates were recovered from patients with SSTIs. All 128 S. aureus SSTI isolates carried at least five virulence genes tested. Virulence genes detected among at least 70% of all tested isolates included hld (100%), hla (95.3%),icaA (96.9%), clf (99.2%),sdrC (79.7%), sdrD (70.3%), andsdrE (72.7%). The prevalence of MRSA isolates with 10 virulence genes tested (54.4%, 31/56) was significantly higher than that among MSSA isolates (35.2%, 25/71) (p < 0.05). The positive rates of seb, sen, sem, sdrE and pvl among MRSA isolates were significantly higher than among MSSA isolates (p< 0.05). ST7 and ST630 accounting for 10.9% were found to be the predominant STs. The most prevalent spa type was t091 (8.6%). MRSA-ST59-SCCmec IV was the most common clone (12.3%) among MRSA isolates whereas among MSSA isolates the dominant clone was MSSA-ST7 (15.5%). Six main clonal complexes (CCs) were found, including CC5 (52.3%), CC7 (11.7%), CC59 (8.6%), CC88 (6.3%), CC398 (4.7%), and CC121 (3.1%). A higher carriage of seb and sec was found among CC59 isolates. In comparison to CC5 and CC7 isolates, those with the highest carriage rates (>80.0%) of sdrC and sdrD, CC59 isolates had lower prevalence of these two virulence genes. All CC59 isolates were susceptible to gentamicin and trimethoprim/sulfamethoxazole, while CC5 and CC7 isolates had resistance rates to these two antimicrobials of 25.4% and 20.9%, and 40.0% and 40.0%, respectively. The resistance rates for tetracycline, clindamycin, and erythromycin among CC5 isolates were lower than among CC7 and CC59 isolates. In conclusion, the molecular typing of S. aureusSSTI isolates in the present study showed considerable heterogeneity. ST7 and ST630 became prevailing clones. Different S. aureus clones causing SSTIs were associated with specific antimicrobial resistance and virulence gene profiles.

Acinetobacter baumannii resistente a carbapenémicos causante de osteomielitis e infecciones de la piel y los tejidos blandos en hospitales de Medellín, Colombia / Carbapenem-resistant Acinetobacter baumannii causing osteomyelitis and infections of skin and soft tissues in hospitals of Medellín, Colombia

Introducción. Acinetobacter baumannii es una bacteria oportunista que infecta a pacientes gravemente enfermos, principalmente con neumonía asociada al uso del respirador y bacteriemia. La aparición de resistencia a los carbapenémicos limita las opciones terapéuticas para el manejo de las infecciones ocasionadas por esta bacteria. Objetivo. Describir las características clínicas y moleculares de las infecciones ocasionadas por A. baumannii resistente a carbapenémicos en hospitales de Medellín. Materiales y métodos. Durante dos años se llevó a cabo un estudio descriptivo de corte transversal en cinco hospitales de Medellín. La información clínica provenía de las historias clínicas. La presencia de carbapenemasas se evaluó mediante el test tridimensional y la técnica de reacción en cadena de la polimerasa. La tipificación molecular se hizo con electroforesis en gel de campo pulsado y tipificación de secuencias de múltiples locus. Resultados. Se incluyeron 32 pacientes, 13 de los cuales presentaban infecciones de la piel y los tejidos blandos (n=7, 21,9 %), y osteomielitis (n=6, 18,7 %). Los porcentajes de resistencia fueron superiores a 80 % para todos los antibióticos evaluados, excepto para la colistina y la tigecilina. Las carbapenemasas OXA-23 y OXA-51, así como la secuencia de inserción IS Aba1 , se detectaron en todos los aislamientos. La electroforesis en gel de campo pulsado reveló una gran diversidad genética en los aislamientos, y la tipificación de secuencias de múltiples locus evidenció la circulación de los clones ST229 y ST758 en la ciudad. Conclusión. Contrario a lo reportado previamente, los resultados del estudio revelaron que la osteomielitis y las infecciones de la piel y los tejidos blandos eran los principales cuadros clínicos causados por A. baumannii resistente a carbapenémicos en instituciones de Medellín, y resaltan su importancia como agente etiológico de este tipo de infecciones.

Introduction: Acinetobacter baumannii is an opportunistic bacterium which infects seriously ill patients, particularly those with ventilator-associated pneumonia and bacteremia. The emergence of resistance to carbapenem limits the options for the treatment of infections caused by this bacterium. Objective: To describe the clinical and molecular characteristics of infections caused by carbapenem-resistant A. baumannii in Medellín hospitals. Materials and methods: A cross-sectional descriptive study was carried out in five Medellín hospitals over a 2-year period. Clinical information was obtained from medical histories of patients. The presence of carbapenemases was evaluated by three-dimensional test and PCR. Molecular typing was performed using PFGE and MLST. Results: The study included 32 patients, 13 of whom presented skin and soft tissue infections (n=7, 21.9%) or osteomyelitis (n=6, 18.7%). Resistance rates of the isolates exceeded 80% for all the antibiotics evaluated except colistin and tigecycline. Carbapenemases OXA-23 and OXA-51, as well as the insertion sequence IS Aba1 , were detected in all the isolates. PFGE revealed high genetic diversity in the isolates and MLST showed clones ST229 and ST758 are circulating in the city. Conclusion: In contrast to previous reports, the results of the present study showed osteomyelitis and infections of skin and soft tissues to be the main infections caused by carbapenem-resistant A. baumannii in Medellín hospitals and revealed its importance as an etiological agent for this type of infections.

Spectrum and potency of ceftaroline against leading pathogens causing community-acquired respiratory tract and skin and soft tissue infections in Latin America, 2010

Ceftaroline, the active metabolite of the prodrug ceftaroline fosamil, is a cephalosporin with in vitro bactericidal activity against Gram-positive organisms, including methicillinsusceptible and -resistant Staphylococcus aureus, β-haemolytic and viridans group streptococci, and Streptococcus pneumoniae, as well as common Gram-negative organisms. In this study a total of 986 isolates collected in 2010 from patients in 15 medical centers in five Latin American countries from the Assessing Worldwide Antimicrobial Resistance Evaluation Program were identified as community-acquired respiratory tract or skin and soft tissue infection pathogens. Ceftaroline was the most potent agent tested against S. pneumoniae with a MIC90 value (0.12 µg/mL) that was eight-fold lower than ceftriaxone, levofloxacin, and linezolid. Its spectrum of coverage (100.0% susceptible) was similar to tigecycline, linezolid, levofloxacin and vancomycin. Against Haemophilus influenzae and Moraxella catarrhalis, ceftaroline was the most active agent tested. The activity of ceftaroline against S. aureus (including MRSA) was similar to that of vancomycin and tetracycline (MIC90,1 µg/mL) and linezolid (MIC90,2 Jg/mL). The 1-haemolytic streptococci exhibited 100.0% susceptibility to ceftaroline. Ceftaroline activity against Escherichia coli, Klebsiella spp., and Enterobacter spp. was similar to that of ceftriaxone and ceftazidime. These parenteral cephalosporin agents have potent activity against non-extended-spectrum These parenteral cephalosporin agents have potent activity against non-extended-spectrum-lactamase-phenotype strains, but are not active against extended-spectrum β-lactamase-phenotype strains. These results confirm the in vitro activity of ceftaroline against pathogens common in communityacquired respiratory tract and skin and soft tissue infection in Latin America, and suggest that ceftaroline fosamil could be an important therapeutic option for these infections.

Community-acquired methicillin-resistant Staphylococcus aureus carrying SCCmec type IV in southern Brazil

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen commonly associated with nosocomial infections. However, it has also been associated with community-acquired skin and soft tissue infections (CA-MRSA). There are few data on the identification and prevalence of CA-MRSA infections in Brazil. METHODS: This is a cross-sectional study of 104 patients with community-acquired skin infections attending two health care centers in Porto Alegre, southern Brazil. MRSA isolates were characterized by molecular methods, including detection of the mecA gene by PCR, gene SCCmec typing, Panton-Valentine leukocidin (PVL) detection, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). RESULTS: From the 104 samples, 58 Staphylococcus aureus isolates were obtained, of which five (8.6%) had a CA-MRSA-resistant profile. All five isolates had the mecA gene and amplified to SCCmec type IV. Analysis of chromosomal DNA by PFGE revealed the presence of two clusters related to international clones (OSPC and USA 300), with a Dice similarity coefficient >80%. The study was complemented by MLST, which detected three different strains: ST30, ST8, and ST45, the latter not presenting any relation with the clones compared in PFGE. CONCLUSIONS: The presence of CA-MRSA reveals an important change in the epidemiology of this pathogen and adds new elements to the knowledge of the molecular biology of infections by MRSA with SCCmec type IV in southern Brazil.

Community-acquired methicillin-resistant Staphylococcus aureus from skin and soft tissue infections (in a sample of Egyptian population): analysis of mec gene and staphylococcal cassette chromosome

BACKGROUND: Staphylococcus aureus has been recognized as an important pathogen associated with inpatients and community infections. Community-acquired methicillin-resistant S. aureus (CA-MRSA) infections commonly present as skin and soft-tissue infections (SSTIs). Treatment often includes incision and drainage with or without adjunctive antibiotics. OBJECTIVES: This study aimed to identify CA-MRSA infections both phenotypically and genotypically, to determine their spectrum of antibiotic resistance, and to establish the best scheme for molecular distinction between hospital-acquired MRSA (HA-MRSA) and CA-MRSA by staphylococcal cassette chromosome mec (SCCmec) typing and detection of Panton Valentine leukocidin (PVL). MATERIALS: 50 swabs, from skin and soft tissue of infected lesions of outpatients attending the dermatology department of the Medical School, Alexandria University, were collected. Additionally, a nasal swab was taken from every participant. METHODS: Collection of swabs from the infected skin and soft tissues, followed by laboratory testing to phenotypically and genotypically identify MRSA. Also, nasal swabs were taken from every patient to identify MRSA colonization. RESULTS: Staphylococcus aureus strains were identified in 38 (76%) of the 50 clinical isolates. 18 (47.37%) out of the 38 S. aureus strains were resistant to oxacillin and cefoxitin discs, were penicillin binding protein 2a (PBP2a) producers, and were initially diagnosed as MRSA. All of the 18 strains were definitively diagnosed as MRSA by mecA gene detection using real time PCR, while only six (33.33%) strains were PVL positive. Using the sets of primers of Zhang et al.: nine (50%) out of the 18 CA-MRSA strains were SCCmec type V, and one (5.56%) was SCCmec type IVc. Then, using the set of primers by Oliveira et al., two (25%) out of the eight untypable MRSA strains were found to be SCCmec type IV, and six (75%) remained untypable. CONCLUSIONS: CA-MRSA must be considered when treating skin and soft tissue infections, especially in developing countries. Empirical use of agents active against CA-MRSA is warranted for patients presenting with serious SSTIs.

Myroides odoratimimus soft tissue infection in an immunocompetent child following a pig bite: case report and literature review

Members of the genus Myroides are aerobic Gram-negative bacteria that are common in environmental sources, but are not components of the normal human microflora. Myroides organisms behave as low-grade opportunistic pathogens, causing infections in severely immunocompromised patients and rarely, in immunocompetent hosts. A case of Myroides odoratimimus cellulitis following a pig bite in an immunocompetent child is presented, and the medical literature on Myroides spp. soft tissue infections is reviewed.

Prevalencia de Staphylococcus aureus resistente a meticilina en infecciones de piel y partes blandas en pacientes ambulatorios / Prevalence of methicillin resistant Staphylococcus aureus in skin and soft tissue infections, in ambulatory patients

Recientemente se ha observado un aumento en la prevalencia de Staphylococcus aureus resistente a la meticilina (SAMR) en pacientes ambulatorios con infecciones de piel y partes blandas (IPyPB). Los datos epidemiológicos locales disponibles son limitados. Se realizó un estudio descriptivo, prospectivo, de consultantes con IPyPB en la División Infectología del Hospital General de Agudos Juan A. Fernández, en el período 01/10/2009 a 31/01/2011. Fueron 130; edad mediana 36 años (RIC 25.9-43.5); hombres 61.5%. El 46.9% era HIV+. Cien cultivos (76.9%), de 100 pacientes, resultaron positivos: 83 S. aureus, 8 Streptococcus spp. y 9 con otros microorganismos. De los S. aureus aislados, 62 (74.7%) fueron resistentes a oxacilina, 12 (14.4%) a clindamicina, 14 (16.9%) a eritromicina, 5 (6%) a ciprofloxacina, presentando en algunos casos más de una resistencia. Todos fueron sensibles a rifampicina y minociclina, y 98.8% (82) a trimetoprima-sulfametoxazol. El 83.8% (52) de los pacientes con SAMR tenían algún factor de riesgo (FR), sin diferencias con los pacientes con otros aislamientos. La presentación clínica más frecuente de IPyPB / SAMR fue forunculosis: 56.4 (35/62) vs. 28.9% (11/38) en infecciones por otros microorganismos (p = 0.013). La resistencia a oxacilina fue similar entre pacientes HIV+ y negativos (79.1 vs. 70%, p = 0.179) (34/43 vs. 28/40). Concluimos que en la población estudiada se encontró una alta prevalencia de SAMR, independientemente de la serología para HIV o la presencia de FR. Las opciones de tratamiento empírico para este microorganismo son minociclina y trimetoprima-sulfametoxazol.

An increased prevalence of community-acquired methicillin resistant Staphylococcus aureus (MRSA) in skin and soft tissue infections (SSTI) has been recently reported. Epidemiological data in Argentina is limited. Our objectives were to evaluate etiological agents, clinical presentation, risk factors and evolution of SSTI in ambulatory patients, in a descriptive and prospective study that was performed at the Infectious Diseases Department, Hospital Fernández, City of Buenos Aires, Argentina, from 10/01/2009 to 01/31/2011. A total of 130 samples were analyzed from 130 patients. Median age: 36 years old (IQR 25.9-43.5); 61.5% were men. HIV infection: 46.9%. Positive cultures were obtained from 100 samples (76.9%): S. aureus 83, Streptococcus spp. 8, and other microorganisms 9. Sixty two (74.7%) of S. aureus isolates were oxacilin resistant, 12 (14.4%) clindamycin resistant, 14 (16.7%) erythromycin resistant and 5 (6%) ciprofloxacin resistant. Some samples presented more than one resistance. All were susceptible to rifampicin and minocycline and 98.8% (82) to trimethoprim- sulfamethoxazole. Of the MRSA patients, 83.8% (52) had at least one risk factor. No significant differences were found in relation to patients with bacterial infections different from MRSA. The most frequent clinical presentation of MRSA-SSTI was furuncle; 56.5% (35/62) vs. 28.9% (11/38) in other SSTI isolations (p = 0.013). Oxacilin resistance was similar among HIV positive and negative patients (79.1 vs. 70%, p = 0.179) (34/43 vs. 28/40). In conclusion: a high prevalence of MRSA was found in this population, irrespective of HIV serology or the presence of risk factors. Empirical treatment options for this microorganism are minocycline and trimethoprim-sulfamethoxazole.

Bacteriemia en pacientes internados con celulitis / Bacteremia in patients hospitalized with cellulitis

La celulitis es una inflamación aguda de la dermis y tejido celular subcutáneo de causa bacteriana, que generalmente complica a heridas, úlceras y dermatosis, aunque de manera frecuente no existe sitio de entrada. Se recomienda la realización de cultivo de punción de piel y partes blandas (PPB). Los hemocultivos raramente dan resultados positivos. El objetivo de este trabajo fue determinar la prevalencia de bacteriemia en pacientes internados en nuestra institución con diagnóstico de celulitis. Se analizaron retrospectivamente los registros clínicos de los pacientes con este diagnóstico al ingreso entre junio de 2007 y marzo de 2010. Se evaluaron los datos poblacionales, presencia de comorbilidades, y resultados de los cultivos. En ese período, se internaron 140 pacientes con diagnóstico de celulitis y a todos ellos se les realizó hemocultivo y cultivos de PPB. Setenta y cuatro eran varones (52.8%). La edad promedio: 47.5 ± 19.7 años (rango 16-94). El 40% tuvo cultivos positivos de PPB, en los que el Staphylococcus aureus meticilino resistente (SAMR) fue el germen más frecuentemente aislado (35.7%); la prevalencia de bacteriemia fue del 8.6%, en donde el germen más frecuente fue Streptoccocus Beta hemolítico, grupo G (33% del total de hemocultivos positivos). La bacteriemia se asoció significativamente a mayor estadía hospitalaria (10.5 ± 8.9 vs. 4.9 ± 6, p = 0.004). Se asoció con mayor riesgo de hemocultivo positivo a ser diabético, tener cultivo de PPB positivo, consumo de alcohol y/o enfermedad pulmonar obstructiva crónica.

Cellulitis is an acute inflammation of dermis and subcutaneous tissue, usually complicating wounds, ulcers, or dermatosis. Even though in these cases it is recommended to perform culture from skin and soft tissue samples, the utility of blood cultures remains controversial due to the low frequency of positive results. Here we report the prevalence of bacteremia in patients with cellulitis admitted in our Hospital, and evaluate the presence of risk factors associated with the occurrence of this event. Clinical records of patients with diagnosis of cellulitis admitted between June 2007 and March 2010 were retrospectively reviewed. Patients without skin and soft tissue culture and/or blood cultures were excluded. Demographic data, presence of comorbidities, and culture results were analyzed. In this period, 140 patients were admitted with this diagnosis. Fifty six (40%) of them had positive skin and soft tissue cultures; where methicillin resistant Staphylococcus aureus (MRSA) was the most frequently isolated bacterium species (35.7%). Bacteremia was detected in 8.6% of these cases, where the most frequently isolated bacteria were Group G Beta haemolytic Streptococcus (33%). Bacteremia was significantly associated with longer hospital stay (10.5 ± 8.98 vs. 4.9 ± 6, p = 0.004). The following variables were significantly associated with the occurrence of positive blood cultures: diabetes (41.7% vs. 14.1%; p = 0.02; OR 4.4), positive skin and soft tissue culture (75% vs. 35.2%; p = 0.01; OR 5.5), alcoholism (16.7% vs. 3.9%; p = 0.01; OR 4.9), and chronic obstructive pulmonary disease (16.7% vs. 0.78%; p = 0.01; OR 25.4).

Daptomicina: características farmacológicas y aporte en el tratamiento de infecciones por cocáceas gram positivas / Daptomycin: pharmacological characteristics and its role in the treatment of gram positive infections

Daptomycin recently made available in Chile, belongs to a new family of antimicrobials known as lypopeptides. Daptomycin has a unique mechanism of action and a potent bactericidal activity over susceptible agents. It is active against a number of clinically significant Gram positive cocci, including strains of Staphylococcus aureus and Enterococcus spp., both susceptible and resistant to classic antimicrobials. Daptomycin has been approved for clinical use in skin and soft tissue infections, and for S. aureus bacteremia in adult patients. Ongoing trials suggest that daptomycin is also useful in the treatment of other infections such as osteomyelitis, biofilm producing infections, and in immunocompromised patients, particularly onco-hematologic patients. The main adverse reaction associated with daptomycin use is myopathy, usually mild and reversible.

Daptomicina es un anti-infeccioso de reciente introducción en Chile, miembro exclusivo de una nueva familia de antimicrobianos conocida como lipopéptidos cíclicos. Tiene un mecanismo de acción único que le confiere un potente efecto bactericida sobre los microorganismos susceptibles. Su especto antimicrobiano comprende cocáceas grampositivas de importancia clínica como Staphylococcus aureus y Enterococcus spp., incluyendo cepas resistentes a antimicrobianos habituales. Está aprobada para el uso clínico en infecciones de piel y tejidos blandos y bacteriemia complicada y no complicada por S. aureus, en adultos. Estudios en curso sugieren que será una alternativa útil en otras infecciones frecuentes como osteomielitis, infecciones asociadas a dispositivos ortopédicos, infecciones asociadas a biopelículas e infecciones en hospederos inmunosuprimidos, en particular en pacientes onco-hematológicos. El principal efecto adverso asociado al uso de daptomicina es la toxicidad muscular, observándose miopatía reversible, la mayoría de las veces asintomática, en aproximadamente 3% de los pacientes que utilizan el fármaco.

Non invasive real-time monitoring of bacterial infection & therapeutic effect of anti-microbials in five mouse models.

Background & objectives: In vivo imaging system has contributed significantly to the understanding of bacterial infection and efficacy of drugs in animal model. We report five rapid, reproducible, and non invasive murine pulmonary infection, skin and soft tissue infection, sepsis, and meningitis models using Xenogen bioluminescent strains and specialized in vivo imaging system (IVIS). Methods: The progression of bacterial infection in different target organs was evaluated by the photon intensity and target organ bacterial counts. Genetically engineered bioluminescent bacterial strains viz. Staphylococcus aureus Xen 8.1, 29 and 31; Streptococcus pneumoniae Xen 9 and 10 and Pseudomonas aeruginosa Xen-5 were used to induce different target organs infection and were validated with commercially available antibiotics. Results: The lower limit of detection of colony forming unit (cfu) was 1.7-log10 whereas the lower limit of detection of relative light unit (RLU) was 4.2-log10. Recovery of live bacteria from different target organs showed that the bioluminescent signal correlated to the live bacterial count. Interpretation & conclusions: This study demonstrated the real time monitoring and non-invasive analysis of progression of infection and pharmacological efficacy of drugs. These models may be useful for pre-clinical discovery of new antibiotics.

Estudio prospectivo, descriptivo y multicéntrico acerca de la infección de piel y partes blandas por Staphylococcus aureus meticilino-resistente adquirido en la comunidad (SAMRAC) / Multicentric prospective and descriptive study about community-acquired methicillin-resistant Staphylococcus aureus cutaneous and sof tissue infection (CA-MRSA)

El Staphylococus aureus meticilino-resistente adquirido en la comunidad (SAMRAC) es uno de los principales patógenos emergentes de la última década, y en algunos países es la principal causa de infecciones de piel y partes blandas. El objetivo de este estudio es describir las características epidemiológicas, clínicas y microbiológicas de las infecciones de piel y partes blandas producidas por SAMRAC en pacientes ambulatorios. Materiales y métodos. Estudio descriptivo, prospectivo, multicéntrico realizado en seis Servicios de Dermatología de la ciudad de Buenos Aires entre julio de 2008 y junio de 2009. Se incluyeron pacientes con infección de piel y partes blandas por SAMRAC documentada por cultivo. La definición de adquisición en la comunidad se basó en criterios epidemiológicos. Resultados. Se reclutaron 114 pacientes, de los cuáles 49% fueron hombres y 51 % mujeres. La media de la edad fue 27 años. El 74% recibió tratamiento con ß lactámicos previo al diagnóstico. Los forúnculos representaron la forma clínica más frecuente (59%), seguido de los abscesos (20%). El antibiótico más indicado fue trimetoprima-sulfametoxasol (68,4%).Las resistencias más frecuentes fueron eritromicina (21,7%) y clindamicina (16,2%), 6 pacientes requirieron internación, 18 pacientes presentaron recurrencias y no se registró ninguna muerte. Conclusiones. Los datos demográficos y clínicos obtenidos en este estudio son similares a los comunicados previamente. La mayoría de los pacientes recibieron tratamiento antibiótico previo, lo que denota una baja sospecha diagnóstica. El impétigo representó una forma de presentación frecuente en la población pediátrica y la celulitis sólo comprometió a mujeres. La resistencia a clindamicina fue mayor al 15%, por lo que no debería ser considerado un antibiótico de primera línea. Las infecciones de piel y partes blandas por SAMRAC son frecuentes en nuestro medio, por lo que debe considerarse en pacientes con lesiones supurativas o falta de...

Community acquired methicillin-resistant Staphylococcus aureus is oneof the main emergent pathogens of the last decade, being the fi rstcause of skin and soft tissue infections in some countries. The purposeof this study is to describe the epidemiologic, clinical, and microbiologicalcharacteristics of CA-MRSA cutaneous and soft tissue infections inan ambulatory setting.Methods. We conducted a multuicentric, prospective, descriptive studyperformed in 6 dermatology units at Buenos Aires from july 2008 to june2009. Patients with documented CA-MRSA skin and soft tissue infectionswere included. Community acquisition was defi ned based on epidemiologiccriteria.Results. We included 114 patients, of which 49% were male and 51%were female. The median age was 27 years. Seventy four percent of the patientshad received beta-lactamic antibiotic treatment prior to inclusion.The main clinical presentation were furuncules (59%) followed by abscesses( 20%). The most frequently prescribed antibiotic was trimethoprim-sulfametoxazole(68,4%). The most frequently recovered isolates were erithromicin-(21,7%) and clindamycin-resistant (16,2%). Six patients requiredhospital admission, 18 had recurrent diseases, and no death was recorded.Discussion. Demographic and clinical data obtained in this study aresimilar to those previously reported. Most of the patients had received antibiotictreatment before inclusion, which shows the low CA-MRSA clinicalsuspicious. Impetigo was fecuently observed among children, and celulitiswas exclusively observed in females. As clindamycin resistance washigher than 15%, this antibiotic should not be considered a fi rst-line treatmentoption. CA-MRSA infections were frecuently observed in our patients,therefore its diagnosis should be considered on suppurative lesionsand non responding pyodermitis (Dermatol Argent 2010;16(2):110-116).

Prevalence of inducible clindamycin resistance in gram positive organisms in a tertiary care centre.

Gram positive organisms are one of the leading pathogens causing skin and soft tissue infections. For these infections, clindamycin is a useful alternate drug in penicillin-allergic patients. This study was conducted to investigate the prevalence of erythromycin-induced clindamycin resistance in gram positive organisms in the southern part of the country. A total of 522 consecutive clinical isolates from blood, CSF, sputum, throat, pus, and urine were collected between November 2006 and April 2007 and tested for erythromycin resistance and inducible clindamycin resistance. There was a relatively higher incidence of inducible clindamycin resistance among the MRSA isolates. We conclude, therefore, that clindamycin is not a suitable alternative antibiotic for use in staphylococcal skin and soft tissue infections.