Isolation and characterization of Yersinia intermedia strains from pig tonsils in Abidjan, Côte d’Ivoire

Abstract

A total of 150 samples of pig tonsils were collected from slaughterhouse in Abidjan; the pigs were from pig farms located in different areas of Côte d’Ivoire. Samples were examined for the presence of Yersinia intermedia. Optimal recovery of Y. intermedia was achieved using two step enrichment procedures based on pre-enrichment in trypticase soya broth at 28 °C for 24 h, followed by cold enrichment method at 4 °C for 21 days in phosphate buffered saline broth. Then, Aulisio’s alkali treatment method was performed before streaking onto MacConkey agar. Six strains of Yersinia intermedia were isolated and tested for the following characteristics associated to the virulence in Y. enterocolitica such as pyrazinamidase activity and autoagglutinability. All the six strains were all positive for the pyrazinamidase test and four of them were autoagglutinable. Four strains were biotype 4/autoagglutinable and two were biotype 5/O:7,8-8-8,19. All the six strains of Yersinia intermedia were rhamnose negative and not motile at 25 °C. The results of antimicrobial resistance showed that all the strains presented multiple antibiotic resistance. The results indicate that 4% of pig tonsils from different farms collected at the slaughterhouse were contaminated with Yersinia intermedia. This study is the first which shows the presence of Yersinia intermedia in pigs in Côte d’Ivoire.

Keywords: Yersinia intermedia, pig tonsils, prevalence, biotype, antibiotic resistance, Côte d’Ivoire