Contamination of Frozen Broiler Chicken Meats with Antimicrobial Resistant Thermophilic Campylobacter in Morogoro, Tanzania

Abstract

Purpose: Majority of the human bacterial gastroenteritis cases in both developed and developing countries in the world are caused by thermo tolerant Campylobacter spp, with C. jejuni and C. coli being more involved. These bacteria live in poultry and other animal's intestinal tracts without causing disease symptoms. Improper handling of carcasses during slaughter and evisceration increases the chance of contaminating the outer skin. Poor meat handling in the kitchen and poor storage during refrigeration causes cross contamination. Methods:This cross-sectional study examined the occurrence of antimicrobial resistant thermophilic Campylobacter in frozen chicken meats in Morogoro Municipality. A total of 272 frozen broiler chicken carcasses were obtained from supermarkets (n=90), meat shops (n=90) and restaurants (n=92). Each carcass was divided into three parts i.e. breast, thighs and wing+neck, rinsed in peptone water. The rinses were then enriched in 5ml of Bolton broth in microerophilic atmosphere at 42ºC for 24hrs. Then the broth was streaked on Modified Charcoal Cefoperazone Deoxycholate Agar (mCCDA) plates followed by incubation at 42ºC for 48 hrs. Presumptive colonies of Campylobacter spp. were sub cultured onto Mueller Hinton Agar and incubated at 42ºC for 48 hrs to obtain pure colonies. Pure Campylobacter colonies were then subjected to preliminary identification using biochemical tests and further confirmed by polymerase chain reaction (PCR). Antimicrobial Susceptibility testing was performed on C. Jejuni isolates by disc diffusion method on Mueller-Hinton agar supplemented with 5% of horse blood. The isolates were tested for resistance against ten antimicrobials namely tetracycline, gentamycin, ciprofloxacin, azithromycin, erythromycin, norfloxacin, chloramphenical, amoxicilin, nalidixic acid and cephalocin.Results: Occurrence of thermophilic Campylobacter spp. in the sampled birds was at a tune of 61.0%. Based on sampling locations the levels of contaminated chicken carcasses were 82.6%, 62.0% and 37.8% for restaurants, shops and supermarkets, respectively. Majority of isolates (72.4%) were Campylobacter jejuni and the remaining proportion (27.6%) was accounted for by C. coli. Frequencies of contamination were comparable between wing+neck and thighs. Wing+neck and thighs had significantly higher frequencies of contamination than breasts (P<0.05). Antibiotic resistance test results for C. jejuni indicated that higher levels (>80%) of resistance were observed for cephalothin, chloramphenical, nalidixic acid, amoxicillin and tetracycline. Lower levels of resistance (<15%) were observed for erythromycin, norfloxacin, azithromycin, ciprofloxacin and gentamicin. Conclusion:This study confirms that in our setting a high frequency of commercial broiler chickens are positive for antimicrobial resistant Campylobacter at the time of slaughter. This phenomenon derives in high contamination of carcasses during the slaughter process thereby constituting a substantial public health hazard. Freezing of carcass...