Polymyxins are last-resort antimicrobial agents used to treat infections caused by carbapenem-resistant Due to the worldwide dissemination of polymyxin resistance in animal and human isolates, we aimed to characterize polymyxin resistance associated with the presence of in 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-positive isolates, and these were further subjected to whole-genome sequencing (WGS). The localization of 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, including 8 , 3 serovar Typhimurium, and 1 isolate isolates were unrelated by PFGE and belonged to 7 different sequence types (STs) and phylogroups. Typhimurium and isolates belonged to ST34 and ST307, respectively. The gene was plasmid borne in all isolates but two isolates which harbored it on the chromosome. Conjugation of was successful in 8 of 10 isolates (8.2 × 10 to 2.07 × 10 cell per recipient). Plasmid sequences showed that the plasmids belonged to four different Inc groups (a new IncP-1 variant and the IncFII, IncHI1, and IncH families). Our results indicate that is circulating in clinical isolates of colistin-resistant in Colombia and is mainly harbored in transferable plasmids.

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Our study confirms that three clones of MRSA predominantly circulate in Colombia: a Chilean clone, a pediatric clone that causes HA-MRSA infections, and a USA300-related clone (SCCmec IVc) in CA-MRSA infections, which differ in the content of clinically important virulence genes. This study confirms that PVL is not a determinant of severity or mortality in CA-MRSA infections.

Salmonellosis is an endemic human infection, associated with both sporadic cases and outbreaks throughout Colombia. Typhimurium is the most common Colombian serovar of Salmonella enterica, responsible for 32.5% of the Salmonella infections. Whole genome sequencing (WGS) is being used increasingly in Europe and the USA to study the epidemiology of Salmonella, but there has not yet been a WGS-based analysis of Salmonella associated with bloodstream infection in Colombia. Here, we analysed 209 genome sequences of Colombian S. Typhimurium and monophasic S. 4,[5],12:i:-isolates from Colombia from 1999 to 2017. We used a core genome-based maximum likelihood tree to define seven distinct clusters which were predominantly Sequence Type (ST) 19isolates. We also identified the first ST313 and monophasic ST34 isolates to be reported in Colombia. The history of each cluster was reconstructed with a Bayesian tree to reveal a timeline of evolution. Cluster 7 was closely related to European multidrug-resistant (MDR) DT104. Cluster 4 became the dominant variant of Salmonella in 2016, and resistance to nalidixic acid was associated with a plasmid-encoded qnrB19 gene. Our findings suggest multiple transfers of S. Typhimurium between Europe and Colombia.

Realpe: identificación bioquímica y serotipificación María Elena Realpe: coordinación de las actividades del programa de vigilancia por el laboratorio de la enfermedad diarreica aguda del Grupo de Microbiología Todos los autores participaron en el análisis de resultados y la revisión del manuscrito. Caracterización molecular de aislamientos de Molecular characterization of Shigella sonnei isolates recovered by the Laboratory Surveillance Program for Acute Diarrheal Disease in ColombiaIntroduction: In Colombia, Shigella sonnei is one of the most frequently isolated serotypes (53.4%) in human clinical samples associated with diarrheal acute disease. The identification of DNA restriction patterns by pulsed field gel electrophoresis is the basis for the molecular surveillance of S. sonnei. Objective: To establish the basis for the molecular surveillance of S. sonnei in Colombia using pulsedfield gel electrophoresis. Materials and methods:We studied 102 of 2,048 S. sonnei isolates referred by the National Laboratory Network between 1997 and March, 2013; the selection was made according to the antimicrobial multiresistance profile, the source of samples, and the relation to outbreaks. The genetic profile was determined by pulsed field gel electrophoresis using the restriction enzymes XbaI and BlnI in accordance with the PulseNet International protocol. The electrophoretic patterns were analyzed with the GelCompare II, version 4.0 software. Results:We obtained 42 electrophoretic patterns with a 70% to 100% similarity. The most frequent pattern was COIN08J16X01.0017 with 17.6%, followed by patterns COIN04J16X01.0004 with