Outbreak of Pseudomonas aeruginosa High-Risk Clone ST309 Serotype O11 Featuring blaPER-1 and qnrVC6.

Pseudomonas aeruginosa is a leading cause of hospital-acquired infections worldwide. Biofilm production, antibiotic resistance, and a wide range of virulence factors contribute to their persistence in nosocomial environments. We describe an outbreak caused by a multidrug-resistant P. aeruginosa strain in an ICU. Antibiotic susceptibility was determined and blaPER-1 and qnrVC were amplified via PCR. Clonality was determined using PFGE and biofilm formation was studied with a static model. A combination of antibiotics was assessed on both planktonic cells and biofilms. WGS was performed on five isolates. All isolates were clonally related, resistant to ceftazidime, cefepime, amikacin, and ceftolozane-tazobactam, and harbored blaPER-1; 11/19 possessed qnrVC. Meropenem and ciprofloxacin reduced the biofilm biomass; however, the response to antibiotic combinations with rifampicin was different between planktonic cells and biofilms. WGS revealed that the isolates belonged to ST309 and serotype O11. blaPER-1 and qnrVC6 were associated with a tandem of ISCR1 as part of a complex class one integron, with aac(6')-Il and ltrA as gene cassettes. The structure was associated upstream and downstream with Tn4662 and flanked by direct repeats, suggesting its horizontal mobilization capability as a composite transposon. ST309 is considered an emerging high-risk clone that should be monitored in the Americas.

Novel Resistance Regions Carrying TnaphA6, blaVIM-2, and blaPER-1, Embedded in an ISPa40-Derived Transposon from Two Multi-Resistant Pseudomonas aeruginosa Clinical Isolates.

Antibiotic resistance is an alarming problem throughout the world and carbapenem-resistant Pseudomonas aeruginosa has been cataloged as critical in the World Health Organization list of microorganisms in urgent need for the development of new antimicrobials. In this work, we describe two novel resistance regions responsible for conferring a multidrug resistance phenotype to two clinical isolates of P. aeruginosa (Pa873 and Pa6415) obtained from patients hospitalized in the ICU of University Hospital of Uruguay. Bacterial identification and antibiotic susceptibility tests were performed using MALDI-TOF and the Vitek 2 system, respectively. WGS was performed for both isolates using Oxford Nanopore Technologies and Illumina and processed by means of hybrid assembly. Both isolates were resistant to ceftazidime, cefepime, piperacillin-tazobactam, aztreonam, and imipenem. Strain Pa6415 also showed resistance to ciprofloxacin. Both strains displayed MICs below the susceptibility breakpoint for CAZ-AVI plus 4 mg/L of aztreonam as well as cefiderocol. Both resistance regions are flanked by the left and right inverted repeats of ISPa40 in two small regions spanning 39.3 and 35.6 kb, for Pa6415 and Pa873, respectively. The resistance region of Pa6415 includes TnaphA6, and the new Tn7516 consists of IRi, In899, qacEΔ1-sul1-ISCR1, qnrVC6-ISCR1-blaPER-1-qacEΔ1-sul1, araJ-like, IS481-like tnpA, ISPa17, and IRR. On the other hand, the resistance region of Pa873 includes Tnaph6 and the new Tn7517 (IRi, In899, qacEΔ1-sul1, ISCR1-blaPER-1-qacEΔ1-sul1, araJ-like, IS481-like tnpA, ISPa17, and IRR). It is necessary to monitor the emergence of genetic structures that threaten to invalidate the available therapeutic resources.

Phenotypic and genotypic characterization of oxacillin-susceptible and mecA positive Staphylococcus aureus strains isolated in Uruguay / Caracterización fenotípica y genotípica de cepas de Staphylococcus aureus sensibles a oxacilina y mecA positivas aisladas en Uruguay

Abstract The aim of this study was to characterize phenotypically and genotypically 27 mecApositive Staphylococcus aureus strains with oxacillin MICs of ≤2 g/ml by Vitek 2, isolated indifferent regions of Uruguay. Susceptibility to oxacillin and cefoxitin was studied by gradient dif-fusion, disk diffusion to cefoxitin, and Phoenix and MicroScan systems. PBP2a was determined.SCCmec typing was performed and the isolates were compared by PFGE. Twenty-six isolateswere susceptible to oxacillin; one strain was susceptible to cefoxitin by disk diffusion and 3strains by gradient diffusion. Phoenix and MicroScan panels detected methicillin resistance in25 and 27 strains, respectively. Twenty-six strains tested positive for PBP2a. Twenty-six strainscarried SCCmec V and 24 belonged to pulsotype A. One strain carried SCCmec IV and did notbelong to pulsotype A. Cefoxitin disk diffusion test and PBP2a detection correctly identified 26of these 27 strains as MRSA. PFGE results suggest the dissemination of a cluster of MRSA carryingSCCmec V.

Resumen El objetivo de este estudio fue caracterizar fenotípicamente y genotípicamente 27 cepas de Staphylococcus aureus positivas para mecA y con CIM de oxacilina <2 pg/ml según Vitek 2, obtenidas en diferentes regiones del país. La sensibilidad frente a la oxacilina y la cefoxitina se estudió por difusión en gradiente, por disco-difusión (cefoxitina) y por los sistemas Phoenix y MicroScan. Se analizó la portación de PBP2a, se realizó la tipificación de SCCmec y las cepas se compararon mediante PFGE. Resultaron sensibles a oxacilina por difusión en gradiente 26 cepas; una fue sensible a cefoxitina por disco-difusión y 3 lo fueron por difusión en gradiente. Los sistemas Phoenix y MicroScan detectaron resistencia a meticilina en 25 y 27 cepas, respectivamente. Asimismo, 26 cepas portaban PBP2a y 26 cepas mostraron presencia de SCCmec V, 24 correspondieron al pulsotipo A. Una portaba SCCmec IV y no perteneció al pulsotipo A. La prueba de disco-difusión con cefoxitina y la detección de PBP2a identificaron 26 de 27 cepas como MRSA. La PFGE sugiere la diseminación de un grupo MRSA con SCCmec V. © 2022 Asociación Argentina de Microbiología. Publicado por Elsevier Espana, S.L.U. Este es un artículo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Phenotypic and genotypic characterization of oxacillin-susceptible and mecA positive Staphylococcus aureus strains isolated in Uruguay.

The aim of this study was to characterize phenotypically and genotypically 27 mecA positive Staphylococcus aureus strains with oxacillin MICs of ≤2µg/ml by Vitek 2, isolated in different regions of Uruguay. Susceptibility to oxacillin and cefoxitin was studied by gradient diffusion, disk diffusion to cefoxitin, and Phoenix and MicroScan systems. PBP2a was determined. SCCmec typing was performed and the isolates were compared by PFGE. Twenty-six isolates were susceptible to oxacillin; one strain was susceptible to cefoxitin by disk diffusion and 3 strains by gradient diffusion. Phoenix and MicroScan panels detected methicillin resistance in 25 and 27 strains, respectively. Twenty-six strains tested positive for PBP2a. Twenty-six strains carried SCCmec V and 24 belonged to pulsotype A. One strain carried SCCmec IV and did not belong to pulsotype A. Cefoxitin disk diffusion test and PBP2a detection correctly identified 26 of these 27 strains as MRSA. PFGE results suggest the dissemination of a cluster of MRSA carrying SCCmec V.

Infecciones urinarias nosocomiales en un hospital universitario: prevalencia, factores predisponentes y agentes etiológicos en salas de cuidados moderados

Resumen: Introducción: Las infecciones nosocomiales constituyen uno de los principales problemas sanitarios a nivel mundial. Una de las más frecuentes es la infección del tracto urinario, cuya frecuencia reportada en Uruguay fue de 9,8% en unidades de Cuidados Intensivos al año 2013. El objetivo fue determinar la prevalencia de infecciones urinarias nosocomiales en salas de cuidados moderados de un hospital universitario, conocer los factores de riesgo asociados a las mismas y el perfil microbiológico de los microorganismos causales. Metodología: Estudio de corte transversal, en salas de cuidados moderados de un hospital terciario y universitario de Montevideo, desde el 1 de agosto de 2017 hasta el 31 de julio de 2018. Se incluyeron pacientes que cumplieron criterios diagnósticos de infección urinaria nosocomial, con urocultivo compatible obtenido luego de 3 días del ingreso. Se completó la recolección de variables mediante entrevista con el paciente y revisión de historia clínica. Resultados: La prevalencia de infección urinaria nosocomial fue de 1,08% en el período de estudio. La mediana de edad fue 62,5 años y 52,3% eran de sexo masculino. La mediana de internación fue de 15 días, la mayoría en salas de Medicina Interna. El 93,2% presentó al menos un factor de riesgo, destacando la exposición a catéter urinario en el 68,3%. El 52,3% de los casos presentó infección urinaria asociada a catéter. El total de los aislamientos microbiológicos fue bacteriano, 84% de bacterias Gram negativas. Klebsiella pneumoniae fue el más prevalente (39,2%), seguido de Escherichia coli (34,2%). Las bacterias Gram positivas correspondieron en su totalidad a Enterococcus spp. Las bacterias Gram negativas mostraron tasas de resistencia mayores al 20% para múltiples antibióticos de varias categorías y 42,1% presentó betalactamasa de espectro extendido. Conclusiones: Las infecciones urinarias nosocomiales en cuidados moderados se presentaron en pacientes con internación prolongada y múltiples comorbilidades. Destaca la exposición a catéter urinario, con un elevado porcentaje de infecciones asociadas al mismo. Los microorganismos causales fueron altamente resistentes a múltiples antibióticos.

Abstract: Introduction: Nosocomial infections are one of the main health problems worldwide. One of the most frequent is urinary tract infection, whose frequency reported in Uruguay was 9.8% in Intensive Care Units in 2013. The objective was to determine the prevalence of nosocomial urinary tract infections in moderate care wards of a universitary hospital, know the risk factors associated with them and the microbiological profile of the causal microorganisms. Methodology: Cross-sectional study, in moderate care wards of a tertiary and universitary hospital in Montevideo, from August 1, 2017 to July 31, 2018. Patients who met diagnostic criteria for nosocomial urinary tract infection were included, with compatible urine culture obtained after 3 days of admission. Variables collection was made through an interview with the patient and a review of the clinical history. Results: The prevalence of nosocomial urinary tract infection was 1.08% during the study period. The median age was 62.5 years and 52.3% were male. The median hospital stay was 15 days, most of them in Internal Medicine wards. 93.2% presented at least one risk factor, highlighting exposure to urinary catheter in 68.3%. 52.3% of the cases presented catheter-associated urinary tract infection. The total of the microbiological isolates was bacterial, 84% of Gram negative bacteria. Klebsiella pneumoniae was the most prevalent (39.2%), followed by Escherichia coli (34.2%). The Gram-positive bacteria corresponded entirely to Enterococcus spp. Gram-negative bacteria showed resistance rates greater than 20% for multiple antibiotics from various categories and 42.1% had extended-spectrum beta-lactamase. Conclusions: Nosocomial urinary tract infections in moderate care occur in patients with prolonged hospitalization and multiple comorbidities. Exposure to urinary catheter stands out, with a high percentage of infections associated with it. The causative microorganisms were highly resistant to multiple antibiotics.

Resumo: Introdução: As infecções hospitalares são um dos principais problemas sanitários a nível mundial. Uma das mais frequentes é a infecção do trato urinário, cuja frequência relatada no Uruguai foi de 9,8% nas Unidades de Terapia Intensiva em 2013. O objetivo foi determinar a prevalência de infecções do trato urinário hospitalares em enfermarias de cuidados moderados de um hospital universitário, conhecer os fatores de risco associados e o perfil microbiológico dos microrganismos causadores. Metodologia: Estudo de corte transversal, em salas de cuidados moderados de um hospital terciário e universitário de Montevidéu, de 1º de agosto de 2017 a 31 de julho de 2018. Foram incluídos pacientes que preencheram os critérios diagnósticos para infecção do trato urinário hospitalar, com urocultura compatível obtida após 3 dias de admissão. A coleta de variáveis foi completada por meio de entrevista com o paciente e revisão da história clínica. Resultados: A prevalência de infecção urinária hospitalar foi de 1,08% no período estudado. A média de idade foi de 62,5 anos e 52,3% eram do sexo masculino. A média de permanência hospitalar foi de 15 dias, a maioria em enfermarias de Clínica Médica. O 93,2% apresentaram pelo menos um fator de risco, destacando-se a exposição ao cateter urinário em 68,3%. O 52,3% dos casos apresentaram infecção do trato urinário associada ao cateter. O total de isolados microbiológicos foi bacteriano, 84% de bactérias Gram-negativas. Klebsiella pneumoniae foi a mais prevalente (39,2%), seguida de Escherichia coli (34,2%). As bactérias Gram-positivas corresponderam inteiramente a Enterococcus spp . As bactérias Gram-negativas apresentaram taxas de resistência superiores a 20% para vários antibióticos de várias categorias e 42,1% apresentaram betalactamasa de espectro estendido. Conclusões: Infecções do trato urinário hospitalares em cuidados moderados ocorreram em pacientes com internação prolongada e múltiplas comorbidades. Destaca-se a exposição ao cateter urinário, com alto percentual de infecções associadas a ele. Os microrganismos causadores foram altamente resistentes a múltiplos antibióticos.

Predictores de tuberculosis pulmonar y experiencia con su diagnóstico molecular rápido / Pulmonary tuberculosis predictors and rapid molecular diagnosis / Preditores de tuberculose pulmonar e experiência com o diagnóstico molecular rápido

Resumen: A nivel mundial se estima que en 2018 hubo alrededor de 10 millones de nuevos casos de tuberculosis (TBC). La detección molecular es una herramienta diagnóstica crecientemente utilizada para el diagnóstico de TBC. Los predictores de riesgo para TBC pulmonar son variados y varían de acuerdo a la población estudiada. Los objetivos del presente trabajo fueron: evaluar la performance de la detección de M. tuberculosis por la técnica Xpert® MTB/RIF para el diagnóstico de TBC pulmonar y determinar los factores predictores de presencia de esta enfermedad en pacientes asistidos en el Hospital Pasteur de Montevideo. Se realizó un estudio descriptivo, observacional y transversal. Se incluyeron 254 pacientes, 68 con TBC pulmonar. La sensibilidad de la prueba Xpert® MTB/RIF para detectar M. tuberculosis fue 100% (IC 95%: 91,2-100) y la especificidad 95,1% (IC 95%: 83,9-98,7). En el análisis multivariado se evidenció que los predictores independientes para presencia de TBC pulmonar fueron: contacto cercano con otro caso de TBC (p<0,001), consumo de pasta base de cocaína (p=0,006) y presentarse con adelgazamiento (p<0,001). En suma, la prueba Xpert® MTB/RIF se comportó como una excelente herramienta diagnóstica en nuestra población con elevada prevalencia de TBC pulmonar. Los predictores independientes para esta enfermedad indican que en la población analizada las estrategias de control de esta enfermedad requieren un abordaje multidisciplinario.

Summary: According to global estimations, there were approximately 10 million new cases of tuberculosis in 2018. Molecular diagnosis constitutes a rapidly growing diagnostic tool for tuberculosis. Risk predictors for pulmonary tuberculosis are varied and they depend on the population studied. The study aimed to assess the performance of M. tuberculosis detection by use of Xpert® MTB/RIF diagnostic test to diagnose pulmonary tuberculosis and to identify predictive factors for this disease in patients assisted at Pasteur Hospital in Montevideo. A descriptive, observational and transversal study was conducted, which included 254 patients, 68 of which had pulmonary tuberculosis. Sensitivity of the Xpert MTB/RIF assay to detect M. tuberculosis was 100% (CI 95%: 91.2-100) and specificity 95.1% (CI 95%: 83.9-98.7). Multivariate analysis evidenced the following to be the independent predictors that detect pulmonary tuberculosis: close contact with other cases of tuberculosis (p<0.001), coca-paste consumption (p=0.006) and evidence of loss of weight (p<0,001). To sum up, the Xpert® MTB/RIF assay proved to be an excellent diagnostic tool in our population with a high prevalence of pulmonary tuberculosis. Independent predictors for this disease show that, in the population studied, control strategies require a multidisciplinary approach.

Resumo: Globalmente, estima-se que em 2018 ocorreram cerca de 10 milhões de novos casos de tuberculose (TB). A detecção molecular é uma ferramenta diagnóstica cada vez mais usada para seu diagnóstico. Os preditores de risco para TB pulmonar são diversos e variam de acordo com a população estudada. Os objetivos deste estudo foram: avaliar o desempenho da detecção do M. tuberculosis pela técnica Xpert MTB/RIF para o diagnóstico da TB pulmonar e determinar os fatores preditivos da presença desta doença em pacientes atendidos no Hospital Pasteur de Montevidéu. Foi realizado um estudo descritivo, observacional e transversal. 254 pacientes foram incluídos, 68 com TB pulmonar. A sensibilidade do teste Xpert® MTB/RIF para detectar M. tuberculosis foi de 100% (IC 95%: 91,2-100) e a especificidade de 95,1% (IC 95%: 83,9- 98,7). A análise multivariada mostrou que os preditores independentes para a presença de tuberculose pulmonar foram: contato próximo com outro caso de tuberculose (p <0,001), consumo de pasta base de cocaína (p = 0,006) e apresentar perda de peso (p <0,001). Em suma, o teste Xpert® MTB/RIF se comportou como uma excelente ferramenta diagnóstica em nossa população com alta prevalência de TB pulmonar. Os preditores independentes para essa doença indicam que, na população analisada, as estratégias de controle da doença requerem uma abordagem multidisciplinar.

Diagnóstico de laboratorio de COVID-19 / COVID-19 laboratory diagnostic / Diagnóstico de laboratório de COVID-19

Resumen: Más de 500 test o pruebas diagnósticas para COVID-19 se están comercializando en el mercado mundial o se encuentran en avanzada fase de desarrollo. En esta situación, sin precedentes, es importante comprender el tipo de ensayos disponibles así como su rol en el proceso diagnóstico. El diagnóstico preciso es clave en el manejo de la pandemia. Esto permite la adecuada identificación de los casos, lo cual habilita las medidas posteriores de control: búsqueda de contactos y aislamiento. En esta revisión describiremos el fundamento y la utilidad de los diferentes tipos de pruebas para diagnóstico etiológico disponibles. También estableceremos las condiciones preanalíticas necesarias para su realización, la sensibilidad y especificidad clínicas, así como la correcta interpretación y emisión de los resultados.

Summary: Over 500 COVID-19 diagnostic tests are available in the global market or are completing the final stages of development. Within this unprecedented framework, it is important to learn about the different types of trials available and understand their role in the diagnostic process. An accurate diagnosis is key for the handling of the pandemic, since it allows for the right identification of cases and thus entitles authorities to take the subsequent control measures: search for contacts and isolation. This review describes the foundations and usefulness of the different types of etiological diagnosis. It also establishes the pre-analytical conditions required to apply them, their clinical sensitivity and specificity, as well as the right interpretation and issuance of results.

Resumo: Mais de 500 testes ou exames diagnósticos para COVID-19 estão sendo comercializados no mercado mundial ou estão em estágio avançado de desenvolvimento. Nesta situação sem precedentes, é importante compreender o tipo de ensaios disponíveis, bem como o seu papel no processo diagnóstico. O diagnóstico preciso é fundamental para controlar a pandemia. Isso permite a identificação adequada dos casos, o que possibilita medidas de controle subsequentes: busca de contatos e isolamento. Nesta revisão, descrevemos a lógica e a utilidade dos diferentes tipos de testes diagnósticos etiológicos disponíveis. Também estabelecemos as condições pré-analíticas necessárias para sua realização, a sensibilidade e especificidade clínicas, bem como a correta interpretação e a liberação dos resultados.

Macrolide-lincosamide-streptogramin B resistance phenotypes and their associated genotypes in Staphylococcus aureus isolates from a tertiary level public hospital of Uruguay / Fenotipos de resistencia a macrólidos lincosamidas-estreptograminas B y sus genotipos asociados en Staphylococcus aureus aislados en un hospital público de nivel terciario en Uruguay

Abstract This study was undertaken to investígate the resistance phenotypes to macrolide-lincosamide-streptogramin B (MLSb) antibiotics and their associated genotypes in isolates of Staphylococcus aureus. We analyzed one hundred, consecutive, non-duplicate isolates (methicillin-susceptible MSSA, n = 53 and methicillin-resistant MRSA, n =47) obtained from var-ious clinical samples between July 2012 to December 2013. The resistance profile to MLSb antibiotics was determined by phenotypic methods and the resistance genes were detected by PCR assays. All of the isolates were subjected to pulsed-field gel electrophoresis (SmaI-PFGE). The overall prevalence of resistance to MLSb antibiotics was 38% and the resistance phenotype distribution was as follows: cMLSb, 22%; iMLSB, 10%; MSb, 5% and L, 1%. We detected ermA, ermC, ermB and mrsA/B genes in these resistant isolates. The single ermA gene was commonly observed mainly in those with a cMLSb R phenotype, whereas the combination ermA and ermC was more commonly observed in isolates with inducible expression. The patterns of SmaI-PFGE suggest a great genetic diversity in both MRSA and MSSA resistant to MLSb antibiotics. The results demonstrate the local presence of S. aureus resistant to MLSb antibiotics and its most frequently described responsible genes. Some of these isolates, especially those with the iMLSB phenotype, may be associated with therapeutic failure. Therefore, efforts should be directed to the correct detection of all MLSb resistant isolates using appropriate laboratory tests. PFGE results reveal a wide spread of resistance genes rather than the circulation of S. aureus clones resistant to MLSb antibiotics.

Resumen Los objetivos de este estudio fueron investigar en Staphylococcus aureus la presencia de fenotipos resistentes a los antibióticos macrólidos, lincosamidas y estreptograminas tipoB (MLSb) y conocer sus genotipos responsables. Analizamos 100 aislamientos consecutivos, no duplicados (53 sensibles a meticilina [MSSA] y 47 resistentes a meticilina [MRSA]), obtenidos entre 2012 y 2013 a partir de diferentes muestras clínicas. El perfil de resistencia a los antibióticos MLSb fue determinado por métodos fenotípicos y los genes de resistencia se detectaron por PCR. Todos los aislamientos fueron comparados por SmaI-PFGE. La prevalencia global de resistencia a los antibióticos MLSB fue del 38% y la distribución de los fenotipos de resistencia fue la siguiente: cMLSB, 22%; iMLSB, 10%; MSB, 5%; L, 1%. Se detectaron los genes ermA, ermC y mrsA/B en los aislamientos resistentes. El gen ermA se observó, sobre todo, en aislamientos con fenotipo resistente constitutivo R (cMLSB), mientras que la combinación ermA y ermC se detectó principalmente en aislamientos con resistencia inducible (iMLSB). Los patrones de Smal-PFGE sugieren una gran diversidad genética en los aislamientos resistentes a los antibióticos MLSb, tanto MRSA como MSSA. Los resultados demuestran la presencia local de S. aureus resistentes a los antibióticos MLSB y de sus genes responsables más frecuentemente descritos. Estos cultivos, especialmente aquellos con fenotipo resistente iMLSB, pueden asociarse con fallas terapéuticas. Por lo tanto, los esfuerzos deben dirigirse a la correcta detección de todos los cultivos resistentes a MLSB utilizando pruebas de laboratorio adecuadas. Los resultados de Smal-PFGE sugieren una amplia diseminación de genes de resistencia, más que la circulación de clones resistentes a los antibióticos MLSB.

[Comamonas kerstersii bacteremia in a young man with acute appendicitis]. / Bacteriemia por Comamonas kerstersii en un joven con apendicitis aguda.

Comamonas kerstersii is a non-fermenting Gram-negative bacillus. It has been associated with intra-abdominal infections. We describe a clinical case of bacteremia caused by C. kerstersii in a young man with acute appendicitis. The first identification, using the Vitek2 compact system (BioMerieux) from blood cultures, was Comamonas testosteroni. However, using MALDI-TOF was identified as C. kerstersii. The patient was treated first with ampicillin sulbactam and then piperacillin tazobactam with favorable evolution. Within the genus Comamonas, C. testosteroni has been the most frequently reported species as a cause of infections in humans, only 23 cases of C. kerstersii being described. Given the problems of phenotypic identification of these microorganisms, it is possible that some C. testosteroni reports could have corresponded to C. kerstersii. This case highlights the pathogenic role of C. kerstersii and the importance of using MALDI-TOF as a diagnostic tool for non-fermenting Gram-negative bacilli identification.

Macrolide-lincosamide-streptogramin B resistance phenotypes and their associated genotypes in Staphylococcus aureus isolates from a tertiary level public hospital of Uruguay.

This study was undertaken to investigate the resistance phenotypes to macrolide-lincosamide-streptogramin B (MLSB) antibiotics and their associated genotypes in isolates of Staphylococcus aureus. We analyzed one hundred, consecutive, non-duplicate isolates (methicillin-susceptible MSSA, n=53 and methicillin-resistant MRSA, n=47) obtained from various clinical samples between July 2012 to December 2013. The resistance profile to MLSB antibiotics was determined by phenotypic methods and the resistance genes were detected by PCR assays. All of the isolates were subjected to pulsed-field gel electrophoresis (SmaI-PFGE). The overall prevalence of resistance to MLSB antibiotics was 38% and the resistance phenotype distribution was as follows: cMLSB, 22%; iMLSB, 10%; MSB, 5% and L, 1%. We detected ermA, ermC, ermB and mrsA/B genes in these resistant isolates. The single ermA gene was commonly observed mainly in those with a cMLSB R phenotype, whereas the combination ermA and ermC was more commonly observed in isolates with inducible expression. The patterns of SmaI-PFGE suggest a great genetic diversity in both MRSA and MSSA resistant to MLSB antibiotics. The results demonstrate the local presence of S. aureus resistant to MLSB antibiotics and its most frequently described responsible genes. Some of these isolates, especially those with the iMLSB phenotype, may be associated with therapeutic failure. Therefore, efforts should be directed to the correct detection of all MLSB resistant isolates using appropriate laboratory tests. PFGE results reveal a wide spread of resistance genes rather than the circulation of S. aureus clones resistant to MLSB antibiotics.

Polyclonal Campylobacter fetus Infections Among Unrelated Patients, Montevideo, Uruguay, 2013-2018.

In Montevideo (2013-2018), 8 Campylobacter fetus extraintestinal infections were reported. The polyclonal nature of strains revealed by whole-genome sequencing and the apparent lack of epidemiological links was incompatible with a single contamination source, supporting alternative routes of transmission.

First characterization of K. pneumoniae ST11 clinical isolates harboring blaKPC-3 in Latin America.

Antimicrobial resistance due to carbapenemase production in Enterobacteriaceae clinical isolates is a global threat. Klebsiellapneumoniae harboring the blaKPC gene is one of the major concerns in hospital settings in Latin America. The aim of this study was to characterize the antibiotic resistance mechanisms and to typify four carbapenem-resistant K. pneumoniae clinical isolates from the city of Manizales, Colombia. We identified blaKPC-3 in all four isolates by polymerase chain reaction and subsequent sequencing. The plasmid-mediated quinolone resistance genes qnrB19-like and aac(6')Ib-cr; fosfomycin resistance gene fosA and an insertion sequence IS5-like in mgrB (colistin resistance) were also detected. Sequence types ST11 with capsular type wzi75, and ST258 with wzi154, were characterized. The blaKPC-3 gene was mobilized in a 100-kb IncFIB conjugative plasmid with vagCD toxin-antitoxin system. This work reports multiple resistance genes in blaKPC-producing K. pneumoniae and the first occurrence of ST11 clinical isolates harboring blaKPC-3 in Latin America.

Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii in the Intensive Care Unit of Uruguay's University Hospital Identifies the First rmtC Gene in the Species.

Carbapenem-resistant Acinetobacter baumannii (CRAB) infections are an increasing concern in intensive care units (ICUs) worldwide. The combination of carbapenemases and 16S rRNA-methyltransferases (16S-RMTases) further reduces the therapeutic options. OXA-carbapenemase/A. baumannii clone tandems in Latin America have already been described; however, no information exists in this region regarding the occurrence of 16S-RMTases in this microorganism. In addition, the epidemiology of A. baumannii in ICUs and its associated resistance profiles are poorly understood. Our objectives were as follows: to study the clonal relationship and antibiotic resistance profiles of clinical and digestive colonizing A. baumannii isolates in an ICU, to characterize the circulating carbapenemases, and to detect 16S-RMTases. Patients admitted between August 2010 and July 2011 with a clinically predicted hospital stay > 48 hr were included. Pharyngeal and rectal swabs were obtained during the first fortnight after hospitalization. Resistance profiles were determined with MicroScan® and VITEK2 system. Carbapenemases and 16S-RMTases were identified by PCR and sequencing, and clonality was assessed by pulsed-field gel electrophoresis and multilocus sequence typing. Sixty-nine patients were studied and 63 were diagnosed with bacterial infections. Among these, 29 were CRAB isolates; 49 A. baumannii were isolated as digestive colonizers. These 78 isolates were clustered in 7 pulsetypes, mostly belonging to ST79. The only carbapenemase genes detected were blaOXA-51 (n = 78), blaOXA-23 (n = 62), and blaOXA-58 (n = 3). Interestingly, two clinical isolates harbored the rmtC 16S-RMTase gene. To the best of our knowledge, this is the first description of the presence of rmtC in A. baumannii.

Detection of qnrVC6, within a new genetic context, in an NDM-1-producing Citrobacter freundii clinical isolate from Uruguay.

OBJECTIVES: The objective of this study was to characterise the mechanisms underlying quinolone and oxyimino-cephalosporin resistance in a Citrobacter freundii clinical isolate obtained from the ICU in a university hospital in Uruguay. METHODS: Citrobacter freundii strain CF638 was isolated from a urine culture. Identification was performed using a VITEK®2 system, and antimicrobial susceptibility was established by MIC determination and disk diffusion assay. Resistance genes and mobile genetic elements were identified by PCR and sequencing. Plasmid transfer was assessed by conjugation and the plasmid size was estimated by S1-PFGE. Plasmid incompatibility (Inc) group and toxin-antitoxin systems were sought by PCR. RESULTS: Strain CF638 showed a multidrug-resistant profile, including resistance to carbapenems and quinolones. Transconjugant TcCF638, harbouring an ca. 200-kb IncA/C plasmid, also showed resistance to all ß-lactams (except aztreonam) and diminished susceptibility to ciprofloxacin. PCR was positive for blaNDM-1 and qnrVC in CF638 and TcCF638. Two different class 1 integrons were detected (In127 and In907). In127 featured the genetic array aadA2-ltr2. Conversely, complex In907 featured two variable regions (VRs); VR-1 consisted of aadB-blaOXA-10-aadA1cc, whereas VR-2 featured a qnrVC6 gene 108bp downstream from ISCR1 and 45bp upstream from qacEΔ1. Expression of qnrVC6 was due to a putative promoter region, detected using the Neural Network Promoter Prediction program. CONCLUSION: To the best of our knowledge, this constitutes the first report of qnrVC within a complex class 1 integron, as well as the first report of the occurrence of such a gene in an NDM-1-producing enterobacterial clinical isolate.

Online continuing interprofessional education on hospital-acquired infections for Latin America

Abstract Introduction: Latin America is a large and diverse region, comprising more than 600 million inhabitants and one million physicians in over 20 countries. Resistance to antibacterial drugs is particularly important in the region. This paper describes the design, implementation and results of an international bi-lingual (Spanish and Portuguese) online continuing interprofessional interactive educational program on hospital-acquired infections and antimicrobial resistance for Latin America, supported by the American Society for Microbiology. Methods: Participation, satisfaction and knowledge gain (through pre and post tests) were used. Moreover, commitment to change statements were requested from participants at the end of the course and three months later. Results: There were 1169 participants from 19 Latin American countries who registered: 57% were physicians and 43% were other health care professionals. Of those, 1126 participated in the course, 46% received a certificate of completion and 54% a certificate of participation. There was a significant increase in knowledge between before and after the course. Of 535 participants who took both tests, the grade increased from 59 to 81%. Commitments to change were aligned with course objectives. Discussion: Implementation of this educational program showed the feasibility of a continent-wide interprofessional massive course on hospital acquired-infections in Latin America, in the two main languages spoken in the region. Next steps included a new edition of this course and a "New Challenges" course on hospital-acquired infections, which were successfully implemented in the second semester of 2015 by the same institutions.