[afro-nets] Open Learning Web site on Enteric pathogens

["Salvatore Rubino" <rubino@uniss.it>]

Open Learning Web site on Enteric pathogens
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Dear Friends of the Open Learning Web site on Enteric pathogens

A new lecture is available at site http://www.oloep.org/www.oloep.org
Genetic Diversity and Quinolone Resistance in Campylobacter isolates from chicken origin in Senegal

Alfred Kinana, Senegal
Pasteur Institute,Laboratory of clinical Medicine, Dakar

To date, there are little data on the epidemiology of  Campylobacter in Senegal. It is known, however, that ciprofloxacin  resistance in Campylobacter isolates derived from commercial  chickens reached 40%.

The aims of this work were (i) to study the genetic diversity of Campylobacter strains isolated from chicken in Senegal, and (ii) to determine the relationship between quinolone resistance, lineages and sequence type (ST).

We used the multilocus sequence typing (MLST) method to study the genetic diversity of 46 C. jejuni and 33 C. coli isolates obtained, respectively, from 14 and 13 dispersed collection sites over a 3-year period. Furthermore, we assessed the resistance of the isolates to ciprofloxacin and nalidixic acid and their gyrA sequences.

In the C. jejuni population, there were 16 ST, and the majority of them belonged to 7 clonal complexes previously identified in human disease. The ST-353 complex was the most common clonal complex whereas the ST-21, ST52 and ST-257 complexes were less well represented. In the C. coli population, there were 13 ST, but only one clonal complex was identified (ST-828 complex).  In term of number of alleles and variable sites, C. coli appeared less variable than C. jejuni. Also, an exchange of alleles between the two species was found. The Thr86-Ile substitution was the predominant mechanism of quinolone resistance, although a small number of isolates had the Thr86-Ala substitution or had no mutation. The resistance phenotype varied for the same ST and within the same lineage.

In conclusion, MLST revealed a low level of diversity and the absence of more lineages among C. coli isolates. There was no link between quinolone resistance and ST. Also, the emergence of quinolone resistance is not related to the diffusion of a unique clone.

ciao Salvatore Rubino


Prof. Salvatore Rubino
Dip. di Scienze Biomediche
V.le San Pietro 43/b
07100 Sassari (Italy)
Tel: +33 79 228302
Fax: +33 79 212345
Cell: +33 83865292
mailto:rubino@uniss.it