María Elena Realpe

Changes in Streptococcus pneumoniae serotype distribution in invasive disease and nasopharyngeal carriage after the heptavalent pneumococcal conjugate vaccine introduction in Bogotá, Colombia.

BACKGROUND In Bogotá, the Heptavalent Conjugate Vaccine (PCV7) was introduced into childhood immunization schedule since 2009. The aim of this study was to assess the changes in serotype distribution and penicillin susceptibility of Streptococcus pneumoniae isolates recovered from nasopharyngeal samples and invasive disease among children living in Bogotá, before and after PCV7 introduction. METHODS Nasopharyngeal swabs were collected from healthy children aged between 12 and 18 months of age before (years 2005-2006) and after (2011) PCV7 introduction. Identification of S. pneumoniae was performed by multiplex PCR. Serotype was determined by PCR and Quellung reaction. Susceptibility to penicillin, ceftriaxone, trimethoprim-sulfamethoxazole, chloramphenicol, tetracycline and erythromycin was evaluated. In addition, distribution of serotypes and antimicrobial susceptibility before and after vaccine introduction among invasive isolates recovered from children ≤2 years old living in Bogotá was analyzed. RESULTS Prevalence of pneumococcal nasopharyngeal carriage declined from 55.7% (137/246) in unvaccinated to 44.2% (87/197) (p=0.01) in vaccinated children. The proportion of children carrying PCV7 serotypes decreased from 23.6% (58/246) to 7.6% (15/197) (p<0.001). The decrease was counterbalanced by an increase in the proportion of non-PCV7 serotypes. The most prevalent among emerging serotypes were 15A, 15B, 15C, 11A and 35B. Among IPD isolates, PCV7 serotypes decreased from 69.1% (235/340) in 2005/2009 to 38.0% (32/84) in 2010/2011 (p<0.001). The increase of non-PCV7 serotypes was significant. Resistance to penicillin among invasive isolates recovered from meningitis decreased from 41.1% (30/73) in the pre-vaccine period to 14.2% (2/14) in post-vaccine period (p=0.02). CONCLUSIONS A decrease in the prevalence of pneumococcal nasopharyngeal carriage following the introduction of PCV7 vaccine, have been overshadowed by an important surge in the prevalence of non-PCV7 serotypes. Systematic surveillance combining nasopharyngeal carriage surveys and IPD detection could help in evaluating the impact of conjugate vaccines.

Whole-Genome Sequence of Multidrug-Resistant Campylobacter coli Strain COL B1-266, Isolated from the Colombian Poultry Chain

ABSTRACT Campylobacter coli is considered one of the main causes of food-borne illness worldwide. We report here the whole-genome sequence of multidrug-resistant Campylobacter coli strain COL B1-266, isolated from the Colombian poultry chain. The genome sequences encode genes for a variety of antimicrobial resistance genes, including aminoglycosides, β-lactams, lincosamides, fluoroquinolones, and tetracyclines.

Caracterización molecular de aislamientos de Shigella sonnei recuperados en el programa de vigilancia por el laboratorio de la enfermedad diarreica aguda en Colombia

INTRODUCTION 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 pulsed-field 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 9.8%, and COIN02J16X01.0002 with 5.8%, while the remaining 66.8% was associated with other electrophoretic patterns. The analysis of 10 outbreaks demonstrated their genetic relation with a 100% of similarity; the most frequent pattern in outbreaks was COIN08J16X01.0017 with 17.1%. CONCLUSION The genotypic database for Shigella sonnei isolates was established using pulsed field gel electrophoresis including the 42 unique patterns identified in this study.

A nalidixic acid-resistant Salmonella Enteritidis outbreak in Popayán, Cauca, 2011

INTRODUCTION Salmonella Enteritidis is recognized worldwide as one of the main agents of human gastrointestinal infection. Several reports indicate the presence of isolates with decreased sensitivity to ciprofloxacin that can lead to a delayed response or the development of resistance during treatment. OBJECTIVE To describe and characterize isolates of Salmonella Enteritidis associated to an outbreak of food-borne diseases in Popayán, Cauca. MATERIALS AND METHODS Ten Salmonella Enteritidis isolates from nine patients and one food sample (chicken sandwich) were analyzed by biochemical tests, serotyping and antimicrobial sensitivity. The minimum inhibitory concentration to ciprofloxacin was determined by E-test and the genetic profile of the isolates was tested by pulsed field gel electrophoresis (PFGE) with XbaI and Blnl enzymes. RESULTS Salmonella Enteritidis was identified in all isolates. They were resistant to nalidixic acid and had a decreased sensitivity to ciprofloxaxin between 0.25 and 0.5 μg/ml; all isolates were sensitive to all the other antimicrobials we tested. Ten isolates were grouped by PFGE with the XbaI enzyme in the COIN11.JEG.X01.0038 pattern, and seven isolates were confirmed with the BlnI enzyme using the COIN11.JEG.A26.0009 pattern. CONCLUSION We report for the first time an outbreak of nalidixic acid-resistant Salmonella Enteritidis in Colombia and confirmed by phenotypic and genotypic analysis the association between the isolates from patients and the chicken sandwich as the source of infection.