Prevalence and Antibiotic Resistance Patterns of Campylobacter spp. Isolated from Broiler Chickens in the North of Tunisia

The aim of the current study is to assess the prevalence of Campylobacter infection in broiler chickens, raised in intensive production conditions, and to evaluate the antimicrobial susceptibility of recovered Campylobacter isolates. A total of 590 cloacal swab samples were taken from 13 broiler chicken flocks in the North East of Tunisia. All samples were tested for the presence of thermophilic Campylobacter by culture and PCR, targeting the mapA and ceuE genes, respectively. Susceptibility to antimicrobial drugs was tested against 8 antibiotics. Prevalence of Campylobacter infection, relationship with geographic origins and seasons, antimicrobial resistance rates and patterns were analyzed. Total prevalence of Campylobacter infection in broiler flocks was in the range of 22.4%, with a predominance of C. jejuni (68.9%), followed by C. coli (31.1%). Positive association was highlighted between the infection level and the season (P < 0.001), but no link was emphasized considering the geographic origin. Antimicrobial susceptibility testing revealed very high resistance rates detected against macrolide, tetracycline, quinolones, and chloramphenicol, ranging from 88.6% to 100%. Lower resistance prevalence was noticed for β-lactams (47% and 61.4%) and gentamicin (12.9%). 17 R-type patterns were observed, and a common pattern was found in 30.3% of isolates. This study provides updates and novel data on the prevalence and the AMR of broiler campylobacters in Tunisia, revealing the occurrence of high resistance to several antibiotics and emphasizing the requirement of better surveillance and careful regulation of antimicrobials use.