CTX-M-15 in combination with aac(6')-Ib-cr is the most prevalent mechanism of resistance both in Escherichia coli and Klebsiella pneumoniae, including K. pneumoniae ST258, in an ICU in Uruguay.

The objectives of this study were (i) to determine the extended-spectrum ß-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EcKp) clones circulating in an intensive care unit (ICU) in Uruguay between August 2010 and July 2011, (ii) to characterise the ESBL and plasmid-mediated quinolone resistance (PMQR) genes of the studied isolates and (iii) to determine the virulotype of the clinical isolates. Clinical and gut-colonising ESBL-EcKp from ICU patients were studied. Bacterial identification and antibiotic susceptibility determination were performed using a VITEK(®)2 system. Detection of ESBL, KPC and PMQR genes was performed by PCR and sequencing. Clonality was assessed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). In total, 54 ESBL-EcKp isolates (40 K. pneumoniae and 14 E. coli), with or without PMQR genes, were recovered from 30 of 68 inpatients. Forty-seven isolates were CTX-M-15-producers (36 as a single ESBL and 11 together with CTX-M-14). In addition, four isolates produced CTX-M-14, two produced CTX-M-2 and one produced SHV-5. No carbapenemases were detected either in E. coli or K. pneumoniae isolates. Among the ESBL-producing isolates, 42 also harboured PMQR genes: 27 aac(6')-Ib-cr; 14 aac(6')-Ib-cr and qnrB; and a single isolate carrying only qnrB. K. pneumoniae ST258, ST48 and ST16 and E. coli ST10 and ST405 were detected in 46/54 isolates, including 9 clinical isolates. In conclusion, non-KPC-producing K. pneumoniae ST258 harbouring different ESBL and PMQR genes was the main clone disseminated in the ICU. Extensive surveillance measures must be implemented to prevent the emergence of acquired plasmid-encoded blaKPC by ST258 K. pneumoniae.

Extended-spectrum ß-lactamases, transferable quinolone resistance, and virulotyping in extra-intestinal E. coli in Uruguay.

INTRODUCTION: To characterize extended-spectrum ß-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli isolates obtained from extra-intestinal samples in three Uruguayan hospitals. METHODOLOGY: Fifty-five ESBL-producing E. coli isolates were studied. Virulence genes, ESBLs, and PMQR genes were detected by polymerase chain reaction. ESBL-producing isolates were compared by pulsed-field gel electrophoresis. Multi-locus sequence typing was also performed on 13 selected isolates. RESULTS: Thirty-seven isolates harbored blaCTX-M-15 (67.3%), eight blaCTX-M-2 (14.6%), five blaCTX-M-14 (9.1%), three carried both blaCTX-M-2 and blaCTX-M-14, one blaCTX-M-9, and one blaCTX-M-8. Among the CTX-M-15 producers, 92% belonged to sequence types ST131 and ST405, and carried aac(6')Ib-cr as well. Isolates harboring blaCTX-M-2, blaCTX-M-14, blaCTX-M-9, or blaCTX-M-8 were found to be genetically unrelated. CONCLUSIONS: The successful dissemination of CTX-M-15-producing E.coli isolates seems to be linked to the spreading of high-risk clones and horizontal gene transfer. A trade-off between carrying more antibiotic resistance and less virulence-related genes could partially account for the evolutionary advantages featured by successful clones.

[Bacteraemia due to Shigella flexneri serotype 6 in two patients with AIDS]. / Bacteriemia por Shigellaflexneri serotipo 6 en pacientes con SIDA: Presentación de dos casos clínicos.

Infections due to Shigella usually remain localized to the digestive tract and are self-limited. Bacteremia is a potentially lethal complication that can occur in immunocompromised patients. We describe two episodes of bacteremia caused by Shigella in two adults with AIDS. In both patients, S. flexneri was recovered from stool and blood samples. The isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrophoresis. Patients received prolonged antimicrobial treatment with a favorable outcome. There were no cases of diarrhea in other individuals admitted to the emergency room. We hypothesized that patient No. 2 was infected at the hospital from patient No. 1. However, we could not establish the way of transmission. Although rare, it is important to take into account the possible occurrence of bacteremia due to Shigella or other bacterial enteropathogens in immunocompromised patients with diarrhea.

Polyclonal endemicity of Acinetobacter baumannii in ventilated patients in an intensive care unit in Uruguay.

OBJECTIVES: To identify the mechanisms responsible for respiratory infections by Acinetobacter baumannii in intubated patients and risk factors for digestive colonization and infection by A. baumannii. METHODS: We conducted a prospective study in an intensive care unit (ICU) between May 2005 and November 2006, including 175 consecutive patients at the beginning of invasive ventilation (day 1). We performed pharyngeal and rectal swabs on days 1, 4, 7, 10, 13, and 16. Respiratory samples were taken on days 1 and 7, or on suspicion of ventilator-associated pneumonia (VAP). RESULTS: We detected 62 patients with A. baumannii digestive colonization and 20 cases of A. baumannii lower respiratory infection (14 VAP and six purulent tracheobronchitis (PTB)). Digestive colonization by A. baumannii was an independent risk factor for lower respiratory tract infections with that microorganism (p<0.0001; relative risk 8.71, 95% confidence interval 2.73-27.77). Respiratory and rectal A. baumannii isolates from the same patients were compared by enterobacterial repetitive intergenic consensus (ERIC)-PCR; in 9/11 cases (eight VAP and one PTB) results suggested events of exogenous pneumonia with previous colonization, whereas the remaining two cases (two PTB) were suggestive of exogenous infection without previous colonization. CONCLUSIONS: In our unit the pathogenesis of VAP by A. baumannii is mixed, most cases corresponding to exogenous pneumonia with previous colonization.

Bacteriemia por Shigellaflexneri serotipo 6 en pacientes con SIDA: Presentación de dos casos clínicos / Bacteraemia due to Shigella flexneri serotype 6 in two patients with AIDS

Infections due to Shigella usually remain localized to the digestive tract and are self-limited. Bacteremia is a potentially lethal complication that can occur in immunocompromised patients. We describe two episodes of bacteremia caused by Shigella in two adults with AIDS. In both patients, S. flexneri was recovered from stool and blood samples. The isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrophoresis. Patients received prolonged antimicrobial treatment with a favorable outcome. There were no cases of diarrhea in other individuals admitted to the emergency room. We hypothesized that patient No. 2 was infected at the hospital from patient No. 1. However, we could not establish the way of transmission. Although rare, it is important to take into account the possible occurrence of bacteremia due to Shigella or other bacterial enteropathogens in immunocompromised patients with diarrhea.

Las infecciones por Shigella spp., en general, permanecen localizadas en el tracto digestivo y tienen una evolución autolimitada. La bacteriemia es una complicación potencialmente letal que ocurre en pacientes con algún tipo de inmunocompromiso. Presentamos dos casos de bacteriemia causadas por Shigella en dos adultos con SIDA. En ambos pacientes, se recuperó Shigella flex-neri en muestras de deposiciones y sangre. Los aislados correspondieron al serotipo 6, fueron resistentes sólo a cotrimoxazol y mostraron un perfil de bandas similar por PFGE. Los pacientes recibieron tratamiento antimicrobiano prolongado y la evolución fue favorable. No se registraron otros casos de diarrea en individuos admitidos en el servicio de emergencia. La hipótesis fue que el paciente 2 adquirió la infección en el hospital a partir del paciente 1. Sin embargo, no pudimos establecer el modo de transmisión. Aunque poco frecuente, es importante tener presente la ocurrencia de bacteriemia por Shigella spp. o por otros enteropatógenos bacterianos en pacientes inmunocomprometidos con diarrea.

Two cases of urinary tract infection caused by Shiga toxin-producing Escherichia coli O157:H7 strains.

STEC strains can infect extra-intestinal sites such as the human urinary tract and sometimes cause severe complications. We report two cases of urinary tract infection caused by STEC in two elderly women with comorbidities. Although both strains belonged to the O157:H7 serotype and carried genes associated with severe illness, none of the patients developed hemolytic uremic syndrome (HUS). These findings provide additional evidence for the presence of these agents in our country and in the region, and highlight the need to maintain an active surveillance system of HUS cases, placing special emphasis on the study of other sites of infection in patients with non-diarrheal HUS.

Infecciones bacterianas en pacientesreceptores de trasplante renal y reno-páncreas: alta incidencia de microorganismos multirresistentes / Bacterial infections in kidney and kidney-pancreas transplant recipients: high incidence of multi-resistant microorganisms

Introducción: las infecciones bacterianas en los receptores de trasplante renal (TR) y reno-páncreas (TRP) son frecuentes y constituyen una de las principales causas de muerte eneste grupo de pacientes. Es imperativo identificar el perfil de estos microorganismos para realizar un mejor abordaje terapéutico empírico.Objetivo: conocer la etiología y las características de las infeccionesbacterianas tanto a nivel comunitario como nosocomial en un grupo de pacientes que recibieron TR y TRP, y fueron asistidos en el Hospital de Clínicas entre noviembre de 1987 y noviembre de 2010. Material y método: estudio retrospectivo de la evolución detodos los pacientes con TR y TRP que ingresados al Hospital de Clínicas hayan presentado por lo menos un episodio infeccioso de etiología bacteriana, sea comunitaria o nosocomial. Se definió como microorganismo multirresistente (MO-MR) si se trató de un SAMR, EVR o un BGN resistente por lo menos a tres grupos de antimicrobianos. Resultados: en el período de estudio, 122 pacientes recibieron un TR o TRP (seis pacientes fueron trasplantados en un centro diferente al Hospital de Clínicas). De aquellos, 64 (52,5%) desarrollaron por lo menos un episodio de infección bacteriana; 34 de sexo femenino (53,1%), con una edad media de 37,7 ± 11,4 años. Treinta y nueve recibieron un TR (60,1%) y 25 (39,1%) un TRP. La mediana de seguimiento fue de cinco meses (P25 = 1, P75 = 25). Hubo 138 episodios de infección bacteriana (2,07 episodios/paciente), de los cuales 76 fueron comunitarias y 62 nosocomiales. El foco más frecuente en ambos fue urinario (63,2% y 53,2%, respectivamente), seguido del respiratorio en las comunitarias (13%). El microorganismo predominante fue E. coli, seguido de Klebsiella spp. y Enterococcus spp. De un total de 103 microorganismos aislados 46 (44,7%) presentaron multirresistencia (con Klebsiella spp. y Acinetobacter baumannii como agentes más frecuentes)...

Introduction: bacterial infections in kidney (KTX) and kidney-pancreas transplant (KPTX) recipients are frequent and constitute one of the leading causes of death in this group of patients. The profile of these microorgapatients with KTX and KPTX who were admitted at the Clinicas Hospital and presented at least one bacterial etiology infection episode, community and hospital-acquired.A multidrug-resistant (MDR) microorganism was defined if it were resistant to MRSA,VREor a gramnegative bacilli resistant to at least three groups of antimicrobial agents.Results: during the period of study 122 patients receivedKTXorKPTX(six patientswere transplanted in a centerdifferent form the Clinicas Hospital). Out of these patients, 64 (52.5%) developed at least one bacterial infectionepisode; 34 of them were women (53.1%), average age was 37.7± 11.4 years old. Thirty nine patients receivedKTX (60.1%) and 25 (39.1%) KPTX. Median follow up was fivemonths (P25 = 1, P75 = 25). There were 138 bacterial infection episodes (2.07 episodes/patient), 76 of which were community acquired and 62 were hospital acquired. In both cases, themost frequent center of infectionwas the urinary system (63.2% and 53.2% respectively), followed respiratory infections in the community acquired infections (13%). E. coli was the predominant microorganism,followed by Klebsiella spp. and Enterococcus spp. Out of 103 microorganisms isolated, 46 (44.7%) evidencedmultidrug-resistance - Klebsiella spp. and Acinetobacterbaumannii being the most frequent agents)...

Introdução: as infecções bacterianas em receptores de transplante renal (TR) e reno-pancreáticos (TRP) são frequentes sendo uma das principais causas de mortneste grupo de pacientes. É fundamental identificar o perfil destes micro-organismos para uma melhor abordagemterapêutica empírica. Objetivo: conhecer a etiologia e as característicasdas infecções bacterianas tanto comunitárias como hospitalaresem um grupo de pacientes que receberam TR e TRP, e que foram atendidos no Hospital das Clínicas noperíodo novembro 1987 - novembro 2010. Material e método: estudo retrospectivo da evolução de todos os pacientes com TR e TRP que internadosno Hospital das Clínicas apresentaram ao menosumepisodio infeccioso de etiologia bacteriana comunitária ouhospitalar. Definiu-se como micro-organismo multirresistente (MO-MR) quando se tratava de um SAMR, EVR ou um BGN resistente ao menos a três grupos de antimicrobianos. Resultados: no período estudado, 122 pacientes receberamumTRouTRP(seis pacientes foram transplantados emumcentro diferente ao doHospital das Clínicas).Do total de pacientes, 64 (52,5%) apresentaram ao menos um episodio de infecção bacteriana; 34 de sexo feminino(53,1%), commédia de idade de 37,7 ± 11,4 anos. Trinta e nove receberam um TR (60,1%) e 25 (39,1%) umTRP. Amediana do seguimento foi de cincomeses (P25 = 1, P75 = 25). Foram registrados 138 episódios de infecção bacteriana (2,07 episódios/paciente), dos quais 76 foram de origem comunitária e 62 hospitalares. Emambos os grupos o foco mais frequente foi urinário (63,2% e 53,2%, respectivamente), seguido do respiratório da comunidade (13%). Omicro-organismo predominante foi E. coli, seguido por Klebsiella spp. e Enterococcus spp. Do total de 103 micro-organismos isolados 46 (44,7%) apresentaram multirresistencia(sendo Klebsiella spp. e Acinetobacter baumannii os agentes mais frequentes)...

Detection of class 1 and 2 integrons, extended-spectrum ß-lactamases and qnr alleles in enterobacterial isolates from the digestive tract of Intensive Care Unit inpatients.

In this study, we searched for extended-spectrum ß-lactamases (ESBLs), class 1 and 2 integrons, and qnrA, qnrB and qnrS genes in 56 oxyimino-cephalosporin and/or ciprofloxacin-resistant enterobacterial isolates obtained from the gastrointestinal tract of patients admitted in an Intensive Care Unit in Uruguay. ESBLs were detected in 11 isolates (6 CTX-M-2, 3 CTX-M-9, 1 CTX-M-15 and 1 PER-2). qnr genes and integrons were detected in 5 and 24 isolates, respectively. Eight different antibiotic resistance gene cassettes were found within six different genetic arrangements. Two types of complex class 1 integrons carrying insertion sequence ISCR1 were found, one showing bla(CTX-M-2)-orf3 and the other qnrA1-ampR. Ten of the thirteen isolates carrying class 2 integrons presented the element IS5 inserted between intI2 and dfrA1, whereas another class 2 integron lacked the internal stop codon usually present in intI2. This is the first report of the occurrence of qnrA, qnrB and bla(CTX-M-9) in Uruguay. Dissemination of the different groups of CTX-M enzymes (i.e. groups 1, 2 and 9) appears to be a recent phenomenon in South America.

Prospective study of risk factors for ventilator-associated pneumonia caused by Acinetobacter species.

UNLABELLED: The incidence of ventilator-associated pneumonia (VAP) by Acinetobacter spp (VAPA) is increasing and has high morbidity and mortality. It is imperative to identify risk factors to be able to use prevention policies. OBJECTIVE: The aim of this study was to identify specific risk factors for VAPA. DESIGN: Prospective cohort study. INTERVENTIONS: None. SETTING: Two medical-surgical intensive care units. MEASUREMENTS: During a period of 36 months, all patients with more than 48 hours on mechanical ventilation and suspected of having a VAP were enrolled. Only VAP with microbiological confirmation was analyzed. RESULTS: Two hundred eighteen consecutive patients with clinical suspicion of VAP were enrolled. One hundred twenty-five VAPs were confirmed by culture--46 by Acinetobacter spp and 79 by other pathogens. The 36 potential risk factors for Acinetobacter spp were analyzed by univariate analysis. Logistic regression identified previous use of ceftriaxone (relative risk, 5.1; 95% confidence interval, 1.47-17.82) and previous use of ciprofloxacin (relative risk, 9.1; 95% confidence interval, 2.29-36.63) as significant independent predictors for the development of VAPA. CONCLUSIONS: Previous use of ceftriaxone and ciprofloxacin are independent risk factors for the development of VAPA.

Conducta frente a la sospecha de infección relacionada a catéter venoso central para hemodiálisis / Suspicious hemodialysis central venous catheter-related infections

Introducción: el poder definir en forma precisa en qué pacientes portadores de un catéter venoso central (CVC) para hemodiálisis con sospecha de infección relacionada a catéter (IRcat) se confirma efectivamente la IRcat, es de vital importancia para evitar el retiro innecesario del mismo en pacientes en quienes frecuentemente existe dificultad para lograr un acceso venoso central. Objetivos: 1) establecer la frecuencia de CVC retirados por sospecha de una IRcat finalmente no confirmada, 2) identificar factores clínicos que nos ayuden a mejorar la precisión diagnóstica de una IRcat. Material y método. Tipo de estudio: observacional, prospectivo. Período de estudio: se realizó durante cinco meses (1º de mayo al 30 de setiembre de 2003) en el Servicio de Nefrología del Hospital de Clínicas. Criterio de inclusión: pacientes mayores de 18 años asistidos en el Departamento de Nefrología, a los cuales se les colocó un CVC para hemodiálisis Resultados: se enrolaron en forma sucesiva 107 CVC, 50 (46,7 por ciento) se retiraron por causa infecciosa y 57 (53,3 por ciento) por otra causa diferente a la infecciosa. Los 50 catéteres retirados por sospecha de IRcat fueron divididos en dos grupos: A) CVC retirados por sospecha de infección y que finalmente tuvieron una IRcat, n = 22 (44 por ciento), y grupo B) CVC retirados por sospecha de infección y que finalmente no tuvieron una IRcat, n = 28 (56 por ciento). Se realizó una comparación de 20 variables a través de un análisis univariado El tener un CVC insertado por más de 14 días se asoció con que la fiebre se corresponda con una IRcat (p = 0,02, OR = 2,1, IC 95 por ciento = 1,2-3,7) Conclusiones: en 56 por ciento de los CVC para hemodiálisis retirados por sospecha de IRcat no se confirmó la infección. El tener insertado un CVC por más de 14 días se relaciona con que la actividad infecciosa se corresponda con una IRcat.

Costos de infecciones intrahospitalarias por Staphylococcus aureus; meticilino resistente vs. meticilino sensible / Cost of Staphylococcus aureus hospital acquired infections, methicilin-resistant vs. methicilin susceptible isolates

La Infección Hospitalaria (IH) es un problema de Salud a nivel mundial por su alta morbimortalidad y costos asistenciales elevados. En Uruguay como otros países de Latino América hay pocos datos sobre los costos de estas infecciones. S. aureus es uno de los patógenos hospitalarios más importantes a nivel mundial, en Uruguay en 1997 constituían el 36% de las IH. Se realizó en el Hospital de Clínicas de Montevideo (hospital universitario de alta complejidad) la vigilancia durante 9 meses de las IH por S. aureus comparando los costos de infecciones por S. aureus meticilino sensible (SAMS) y S. aureus meticilino resistente (SAMR). Se utilizaron las recomendaciones de “Infection Control and Hospital Epidemiology” y las guías de Wenzel y cols. para la definición de las diferentes infecciones. Se analizaron 67 infecciones 33 SAMS y 34 SAMR. Treinta y cuatro correspondieron a infecciones del torrente sanguíneo (ITS) y 16 infecciones del sitio quirúrgico (ISQ). Los indicadores de costos utilizados fueron la estadía hospitalaria por la infección por nivel de servicio, estudios realizados para diagnóstico y evaluación de la infección y tratamiento antibiótico. Se compararon los costos de las infecciones por SAMR y SAMS. Se encontraron diferencias estadísticamente significativas en las infecciones del torrente sanguíneo, mediana de 5916 dólares en pacientes con SAMR y 1963 dólares en SAMS. Es importante continuar con estudios de vigilancia y de costos de las IH para tener mayor conocimiento de estas así los administradores y trabajadores de la Salud podrán tener mejores argumentos para realizar medidas de prevención y control

Enterococos resistentes a vancomicina: un problema emergente en Uruguay / Vancomycin-resistant enterococcus: an emergent problem in Uruguay

En las dos últimas décadas los enterococos han pasado de ser considerados comensales de baja patogenicidad a convertirse en una importante causa de infección intrahospitalaria. Por ser cocos grampositivos, anaerobios facultativos y catalasa negativos, en el pasado se los consideró como pertenecientes al género Streptococcus; sin embargo, estudios genéticos marcaron claras diferencias, por lo cual a partir de la década de 1980 se constituyeron como un nuevo género llamado Enterococcus. Presentan resistencia antibiótica intrínseca de bajo nivel a betalactámicos y aminoglucósidos. Pueden adquirir resistencia de alto nivel a los mismos grupos de antibióticos y además han adquirido resistencia a glicopéptidos (vancomicina y teicoplanina). Este se presenta, actualmente, como el gran problema de resistencia emergente en este género, particularmente en Enterococcus faecium. Se han reportado siete genotipos de resistencia a glicopéptidos denominados vanA a vanG, de los cuales hasta el momento sólo dos (vanA y vanB) tienen impacto clínico por su capacidad de transferencia entre especies y géneros diferentes. Las infecciones por enterococos resistentes a la vancomicina (ERV) se producen casi exclusivamente a nivel hospitalario. Los tres primeros casos de este tipo detectados en Uruguay fueron aislados de una colonización urinaria, una infección intraabdominal polimicrobiana y una endocarditis infecciosa. La circulación de cepas de ERV en un centro de salud obliga a implementar medidas de vigilancia activa para identificar los reservorios y así hacer posible las medidas de control de la diseminación cruzada. El objetivo de esta comunicación ha sido la notificación de aislamientos de Enterococcus faecium resistentes a la vancomicina en nuestro medio, acompañada de una actualización del tema que permite comprender el significado, la trascendencia de lo informado y las medidas de control que se plantean.