Prevalence, Antimicrobial Usage And Resistance Profiles Of Campylobacter In Commercial Broiler Production Systems In Kenya

Abstract

Antimicrobial resistance (AMR) is the ability of a microbe to resist the effects of medication previously used to treat them. This phenomenon has emerged as a public health concern globally. Campylobacter is one of the four key global causes of diarrhea diseases and it is considered to be the most common bacterial cause of human gastroenteritis in the world. The high incidence of Campylobacter diarrhoea, as well as its duration and possible complications, makes it highly important from a socio-economic perspective. This bacterium is commonly found as a contaminant of foods of animal origin particularly poultry products. Humans get infected by consumption of contaminated meat and meat products. Studies in Kenya and elsewhere indicate that poultry are the major source of Campylobacter infections in humans. Poultry production is an important economic activity in Kenya both in large scale (commercial) and small holder set ups. However, the situation in commercial broiler production systems in Kenya with regard to Campylobacter bacteria has not been previously evaluated. The purpose of this study was to assess the prevalence and antimicrobial resistance profiles of Campylobacter in intensively managed commercial broiler production systems in Kenya to three commonly used antibiotics namely ciprofloxacin, tetracycline and erythromycin, and genetic characterization of the various species of Campylobacter occurring in the broilers. A cross-sectional study with the specific objectives being to determine the prevalence levels, genetic characterization of the various species of Campylobacter and antimicrobial resistance profiles to commonly used antibiotics in Kenya, was carried out between February 2015 and October 2016. Cloacal swabs were collected from a total of randomly selected 600 day-old-chicks at the hatchery over a period of four consecutive months at a rate of 150 samples per month. xvi Likewise, 300 (n=300) cloacal samples were collected from randomly selected broilers that were ready for slaughter for purposes of consumption. Fifty samples were collected from each farm. These broilers were from farms located in six counties of Kenya, namely Kajiado, Machakos, Murang’a, Kiambu, Nairobi and Nakuru. The sample collection was done at a point just before the carcasses entered into the scalding tank. The sterile swabs used for cloacal swabbing were immediately immersed into Stuart® transport media and stored in a cooler box and transported to the laboratory at the Faculty of Veterinary Medicine, Department of Public Health Pharmacology and Toxicology for microbiological evaluation. The cloacal swabs from day old and 33-day old market - ready broilers were streaked on charcoal cefoperazone dextrose agar (CCDA), and anaerobically cultured at 42oC for 48 hours and morphological characteristics described. The Kirby-Baeur disk diffusion method of antimicrobial sensitivity determination was used and zones of inhibition diameters were compared with the EUCAST v 7.1 clinical break-point standards for interpretation. The raw data collected were entered into MS Excel v.2016, with positive samples recorded as numeral 1 (one) and negatives as 0 (zero). The same was applied to antimicrobial sensitivity where 1 represented sensitivity and 0 represented non-sensitivity. These data were then imported into SPSS v.20 statistical software for analysis to determine the prevalence, proportions, means and analysis of variance (ANOVA). A structured questionnaire was administered to supervisor and manager of each farm to gather information on day to day management of the broiler farms and knowledge levels regarding antimicrobial usage. No Campylobacter growth was reported from all the samples from the hatchery while bacterial growth was reported from samples from market ready birds from all the counties with the general prevalence rate of 92.3% (range of 80 to 100%), highest in Murang’a and lowest in Kajiado counties. The species identified included C. jejuni (66%), C. lari,(10%), C. coli (5%), C. fetus xvii (1.7%), C. upsaliensis (1.7%) and C. hyoinstestinalis(0.6%). C. jejuni was the most prevalent and occurred in all counties while C. hyointestinalis had low prevalence and was only reported from Machakos county. The Campylobacter species were found to be resistant to ciproflaxacin, tetracycline and erythromycin which are commonly used in poultry production. Two counties (Kajiado and Nakuru) had prevalence rates of 82% and 88% for C. jejuni respectively, while the rest of the counties had over 90%. On average 98.5% of the isolates showed resistance to ciprofloxacin while 100% were resistant to both tetracycline and erythromycin. This study found that the types of antimicrobials used in the commercial broiler farms were phosphomycin/ tylosin and phenol. None of the farms reported using ciprofloxacin or erythromycin but one had used tetracycline at one time only. On the contrary these antimicrobials are commonly used by small scale broiler farmers, humans and other animals. This may attribute to the high resistance rates observed. The study concluded that there was prudent use of indicated antimicrobials and Campylobacter species were present in market - ready broilers from commercial large-scale production systems in Kenya at high prevalence rates with C. jejuni as the most prevalent. The isolates also exhibited high resistance levels to antimicrobials commonly used in both veterinary and human medicine. It is recommended from this study that the farm management should engage managers and supervisors with a good level of knowledge on antimicrobials. Ineffective antimicrobials should be avoided or withdrawn. Further studies should be done to establish at what age broilers become infected and also if the critical control points in processing plants are effective in the control of Campylobacter contamination.