María Victoria Ovalle

Emergencia de fenotipos resistentes a cefalosporinas de tercera generación en Enterobacteriaceae causantes de infección del tracto urinario de inicio comunitario en hospitales de Colombia

INTRODUCTION Urinary tract infection (UTI) is a common disease in the community, and a matter of concern due to the increasing resistance of microorganisms to first line antibiotics and the emergence of multiresistant strains producing extended spectrum beta lactamases (ESBL) in the community. METHODS An analytical case-control study was conducted over twelve months in 9 hospitals in Colombia. We collected isolates of E. coli, Klebsiella spp. and Proteus spp. from patients with community-onset UTI. The presence of ESBL, AmpC and KPC beta-lactamases were characterized by microbiological and molecular methods. The aim of this study was to determine factors related to the presence of these mechanisms of the resistance to third generation cephalosporins. RESULTS A total of 325 isolates (287 E. coli, 29 Klebsiella spp. and 9 Proteus spp.) were included. The most frequent comorbidities among the patients were hypertension (n=82; 25.2%) and diabetes mellitus (n=68; 20.9%). Previous use of antimicrobials was found in 23% of patients, and 29% had a previous UTI. Resistance to third and fourth generation cephalosporins varied between 3.4% and 6.3% in E. coli and between 6.9% and 17.8% in K. pneumoniae. Seven (2.4%) CTX-M-15 ESBL-producing E. coli isolates were detected; four of them belonged to ST 131 clone. In K. pneumoniae we detected three KPC-3 carbapenemases (10.3%). CONCLUSIONS This study confirms the emergence of resistance to third generation cephalosporins enterobacteriaceae as a cause of community-onset UTI. We emphasize the presence of ST 131 clone and KPC carbapenemases circulating in Colombia outside the hospital environment.

Genomic and Molecular Characterization of Clinical Isolates of Enterobacteriaceae Harboring mcr-1 in Colombia, 2002 to 2016

ABSTRACT Polymyxins are last-resort antimicrobial agents used to treat infections caused by carbapenem-resistant Enterobacteriaceae. Due to the worldwide dissemination of polymyxin resistance in animal and human isolates, we aimed to characterize polymyxin resistance associated with the presence of mcr-1 in Enterobacteriaceae and nonfermenter Gram-negative bacilli, using isolates collected retrospectively in Colombia from 2002 to 2016. A total of 5,887 Gram-negative clinical isolates were studied, and 513 were found to be resistant to the polymyxins. Susceptibility to colistin was confirmed by broth microdilution for all mcr-1-positive isolates, and these were further subjected to whole-genome sequencing (WGS). The localization of mcr-1 was confirmed by S1 pulsed-field gel electrophoresis (S1-PFGE) and CeuI-PFGE hybridization. Transferability was evaluated by mating assays. A total of 12 colistin-resistant isolates recovered after 2013 harbored mcr-1, including 8 Escherichia coli, 3 Salmonella enterica serovar Typhimurium, and 1 Klebsiella pneumoniae isolate. E. coli isolates were unrelated by PFGE and belonged to 7 different sequence types (STs) and phylogroups. S. Typhimurium and K. pneumoniae isolates belonged to ST34 and ST307, respectively. The mcr-1 gene was plasmid borne in all isolates but two E. coli isolates which harbored it on the chromosome. Conjugation of mcr-1 was successful in 8 of 10 isolates (8.2 × 10−5 to 2.07 × 10−1 cell per recipient). Plasmid sequences showed that the mcr-1 plasmids belonged to four different Inc groups (a new IncP-1 variant and the IncFII, IncHI1, and IncH families). Our results indicate that mcr-1 is circulating in clinical isolates of colistin-resistant Enterobacteriaceae in Colombia and is mainly harbored in transferable plasmids.

Actividad in vitro de Tedizolid y comparadores en aislamientos de Staphylococcus aureus resistentes a meticilina en infecciones de piel y tejidos blandos en 7 hospitales de Colombia

Introducción. Staphylococcus aureus resistente a meticilina (SARM) causa infecciones graves de la piel y los tejidos blandos en los hospitales y, en los últimos años, en la comunidad. El tedizolid es una nueva oxazolidinona cuya potencia in vitro ha demostrado ser mayor que la del linezolid frente a este microorganismo.Objetivo. Conocer la actividad antimicrobiana del tedizolid y de algunos antibióticos de comparación en aislamientos de SARM causante de infecciones de piel y tejidos blandos en hospitales de Colombia.Materiales y métodos. Se hizo un estudio multicéntrico prospectivo y descriptivo a lo largo de doce meses en siete hospitales de tercer nivel de Colombia. Se recolectaron aislamientos de SARM de pacientes adultos con infección de piel y tejidos blandos. Se determinó la concentración inhibitoria mínima (CIM) mediante la técnica de ETEST® (bioMérieux) del tedizolid, el linezolid, la vancomicina, la daptomicina, el trimetoprim-sulfametoxazol y la clindamicina.Resultados. Se obtuvieron aislamientos de SARM de 102 pacientes, de los cuales 56 (54,9 %) eran hombres; el promedio de edad fue de 46,8 años. La infección tuvo origen en la comunidad en 77 casos (75,4 %). El tipo de muestra que predominó fue el absceso (69 pacientes: 67,6 %). Todos los aislamientos fueron sensibles a tedizolid, linezolid, daptomicina, trimetoprim-sulfametoxazol y vancomicina. La actividad in vitro del tedizolid fue mayor que la del linezolid. Los intervalos de la CIM del tedizolid oscilaron entre 0,125 μg/ml y 0,5 μg/ml en tanto que los del linezolid fluctuaron entre 1 μg/m y 2 μg/ml.Conclusiones. Las cepas circulantes de SARM en Colombia presentaron una gran sensibilidad al tedizolid, por lo cual sería una alternativa terapéutica para las infecciones de piel y tejidos blandos en nuestro medio.

Resultados de la vigilancia nacional de la resistencia antimicrobiana de enterobacterias y bacilos Gram negativos no fermentadores en infecciones asociadas a la atención de salud, Colombia, 2012-2014

INTRODUCTION The Colombian National Antimicrobial Resistance Monitoring System for the surveillance of healthcare-associated infections was set up to meet this problem in the third quarter of 2012. OBJECTIVE To describe resistance profiles and laboratory-based surveillance based on the information collected by the System. MATERIALS AND METHODS We conducted a retrospective and descriptive study of the information notified to the Colombian Public Health Surveillance System (Sivigila), and in the Whonet databases covering the period from July 2012 to December 2014 provided by the primary data-generating units in the country, as well as laboratory surveillance results from 1,642 phenotypic and genotypic tests on carbapenemase isolates (927 from Enterobacteriaceae, 614 from Pseudomonas spp. and 101 from Acinetobacter spp.). RESULTS There was a significant increase in Escherichia coli resistance to third-generation cephalosporins (reaching 26.3% in ICUs and 22.5% in other hospital wards), and Klebsiella pneumoniae resistance to ertapenem also increased (reaching 14.6% in ICUs). Acinetobacter baumannii carbapenem resistance exceeded 50% in ICUs whereas Pseudomonas aeruginosa had lower carbapenem resistance (38.8%). KPC (n = 574) and NDM (n=57) were the most frequently occurring carbapenemases in Enterobacteriaceae, VIM (n=229) and KPC (n=114) in P. aeruginosa, and OXA-23 in A. baumannii (n=87); several carbapenemase combinations were identified, KPC + VIM being the most common in Pseudomonas spp. and Enterobacteriaceae. CONCLUSION The data from the surveillance of healthcare-associated infections revealed significant carbapenem resistance profiles and antimicrobial resistance mechanisms circulating in Colombian healthcare institutions.