Trends in the epidemiology of pandemic and non-pandemic strains of Vibrio parahaemolyticus isolated from diarrheal patients in Kolkata, India

PLoS Negl Trop Dis. 2014 May 1;8(5):e2815. doi: 10.1371/journal.pntd.0002815. eCollection 2014 May.

Abstract

A total of 178 strains of V. parahaemolyticus isolated from 13,607 acute diarrheal patients admitted in the Infectious Diseases Hospital, Kolkata has been examined for serovar prevalence, antimicrobial susceptibility and genetic traits with reference to virulence, and clonal lineages. Clinical symptoms and stool characteristics of V. parahaemolyticus infected patients were analyzed for their specific traits. The frequency of pandemic strains was 68%, as confirmed by group-specific PCR (GS-PCR). However, the prevalence of non-pandemic strains was comparatively low (32%). Serovars O3:K6 (19.7%), O1:K25 (18.5%), O1:KUT (11.2%) were more commonly found and other serovars such as O3:KUT (6.7%), O4:K8 (6.7%), and O2:K3 (4.5%) were newly detected in this region. The virulence gene tdh was most frequently detected in GS-PCR positive strains. There was no association between strain features and stool characteristics or clinical outcomes with reference to serovar, pandemic/non-pandemic or virulence profiles. Ampicillin and streptomycin resistance was constant throughout the study period and the MIC of ampicillin among selected strains ranged from 24 to >256 µg/ml. Susceptibility of these strains to ampicillin increased several fold in the presence of carbonyl cyanide-m-chlorophenyldrazone. The newly reported ESBL encoding gene from VPA0477 was found in all the strains, including the susceptible ones for ampicillin. However, none of the strains exhibited the β-lactamase as a phenotypic marker. In the analysis of pulsed-field gel electrophoresis (PFGE), the pandemic strains formed two different clades, with one containing the newly emerged pandemic strains in this region.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • DNA, Bacterial / analysis
  • DNA, Bacterial / genetics
  • Diarrhea
  • Drug Resistance, Bacterial
  • Feces / microbiology
  • Humans
  • India / epidemiology
  • Linear Models
  • Microbial Sensitivity Tests
  • Pandemics*
  • Serotyping
  • Vibrio Infections / epidemiology*
  • Vibrio Infections / microbiology*
  • Vibrio parahaemolyticus / classification
  • Vibrio parahaemolyticus / drug effects
  • Vibrio parahaemolyticus / genetics
  • Vibrio parahaemolyticus / isolation & purification*

Substances

  • Anti-Bacterial Agents
  • DNA, Bacterial

Grants and funding

This work was supported in part by the Indian Council of Medical Research, New Delhi, India and Japan Initiative for Global Research Network on Infectious Diseases, Ministry of Education, Culture, Sports, Science and Technology, Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.