Current methodologies and future direction of Campylobacter isolation and detection from food matrices, clinical samples, and the agricultural environment.

Campylobacteriosis is an emerging zoonotic enteric disease that poses a threat to both human health and animal productivity. Poultry is known as the primary reservoir of Campylobacter, and 90% of human Campylobacteriosis is caused by Campylobacter jejuni and Campylobacter coli. This is complicated by the worldwide emergence of Campylobacter strains that are resistant to commonly used antimicrobial compounds. In this study, we determined the prevalence and antimicrobial susceptibility profiles of Campylobacter coli isolated from cloacal swabs collected from broilers and layers in Mwanza and Arusha, Tanzania. We collected 402 cloacal swabs from broilers and layers. Then, samples were enriched into Bolton Broth supplemented with 5% laked horse blood. Campylobacter was isolated and confirmed by PCR. Antibiogram was done by disk diffusion method using six antibiotics i.e., ampicillin, nalidixic acid, gentamycin, erythromycin, tetracycline, and ciprofloxacin. Of the 402 samples, 31 (7.71%) were confirmed to be Campylobacter coli by PCR. In Mwanza, the overall prevalence was 6.5% (6% and 7% in broilers and layers, respectively), while in Arusha, the overall prevalence was 8.9% (10.8% and 7% in broilers and layers, respectively). Antimicrobial susceptibility testing showed that 80.6%, 16.1%, 9.7%, 9.7%, 6.5%, and 3.2% were resistant to ampicillin, nalidixic acid, erythromycin, tetracycline, ciprofloxacin, and gentamycin, respectively. The rate of antimicrobial resistance (AMR) to at least one antimicrobial was 100%. Eight out of thirty-one (12.9%) isolates were multi-drug-resistant to four different antimicrobial compounds, each with different patterns. Wise use of existing antimicrobials is necessary to curb the increasing trend of AMR strains.

Prevalence and antimicrobial susceptibility profiles of Campylobacter coli isolated from broilers and layers cloacal swabs in Mwanza and Arusha, Tanzania

The filtration method (FM) is the most effective isolation technique for Epsilobacteriaceae from stool samples. FM’s different adaptations make it difficult to compare data between studies. This study was performed in three phases to optimize FM from a routine laboratory perspective. In July–September 2014 (part I), FM was performed on Mueller–Hinton agar containing 5% sheep blood and Columbia agar containing 5% sheep blood. In July 2016 (part II), FM was performed using 0.60-μm pore size polycarbonate filters (0.6-PC filter) and 0.45-μm pore size cellulose acetate filters (0.45-AC filter); in January 2018 (part III), the addition of hydrogen to incubators was studied. On 1146 stools analyzed in part I, the positive samples that showed no growth on the Butzler medium (n = 22/72, 30.6%) had improved growth of Epsilobacteriaceae when using the Columbia instead of the Mueller–Hinton medium (21/22 strains vs. 11/22, p < 0.05). In part II, on 718 stools, 91 strains grew with FM (12.7%), more with 0.6-PC filter (90/91) than with 0.45-AC filter (44/91) (p < 0.05). In part III, 578 stools were cultured, 98 Epsilobacteriaceae strains grew with FM, and 7% hydrogen finding significantly more Epsilobacteriaceae than without hydrogen (90/98, 91.8%, vs. 72/98, 73.5%; p < 0.05). The use of a Columbia medium containing 5% sheep blood with 0.6-PC filters incubated at 37 °C in a 7% hydrogen-enriched atmosphere led to an almost fourfold increase in the isolation rate of Epsilobacteriaceae among the studied combinations. Reference centers for Campylobacter should use standardized protocols to enable the comparison of prevalence in space and time.

Helga Marisca Kandet Yattara

Papers

Multi-step optimization of the filtration method for the isolation of Campylobacter species from stool samples