Detection of antibiotic resistance and virulence genes in Escherichia coli from broiler chicken at Tigoni processing plant in Limuru, Kenya
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Date
2014-04-22
Authors
Adelaide, O. A.
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Abstract
The use of antibiotics and disinfectant in broiler farms is common compared to other poultry
farms. Antimicrobial usage is considered the most important risk factor promoting the
emergence, selection and spread of antimicrobial-resistant micro organisms in environment,
veterinary and human medicine. The aim of this study was to investigate antibiotic resistance
and prevalence of virulence related genes in caecal Escherichia coli isolates from healthy
broiler chicken at slaughter time. One hundred and seventy three E. coli isolated from caecal
samples of broiler chickens were screened by disc diffusion to determine their susceptibility
profile for six commonly used antibiotics. Sixty four samples were analyzed for virulence
related genes using multiplex PCR. Extraction of DNA was done on sixty four isolates as
follows; overnight broth bacterial suspensions were adjusted to 0.5 McFarland standard in
sterile deionised water, boiled for 10 minutes and centrifuged for 5 min at 10,000RPM high
speed then 5111of supernatant was used for PCR. Seven sets of primers were used in two
multiplex reaction tubes. Seven virulence related genes were investigated but nine isolates
were positive for verotoxin and three for intimin. Serotyping was done only for positive by
slide agglutination, E.coli was grown overnight on suitable agar media (beef extracted agar)
not inhibiting motility. High resistance levels were detected for most commonly used drugs
like tetracycline (75.9%) and Cotrimoxazole (72.4%). One hundred and seventeen isolates
showed resistance to two and more antibiotics. Different farm treatments were a significant
factor for multidrug resistance (p:SO.OOI). The E. coli isolates showed twenty-one different
multidrug resistant patterns with tetracyc\ine/cotrimoxazole being the most common. Serotype
0111, 0126, 06 and 078 were positive for verotoxin, 0126 and 0111 were positive for
intimin. There was no significant relationship between virulence and multi-drug resistance
(p:SO.05). The present study highlights the presence of multi-drug resistant and virulent E. coli
among healthy broilers chicken in Nairobi- Kenya. The source of antibiotic resistance in the
broilers is thought to be due selective pressure by the commonly used drugs. Other antibiotics
like ampicillin (39%), chloramphenicol (13.2%) and ciprofloxacin (19%) recorded relatively
high resistance levels yet rarely used in poultry farming, this may have been due co-selection
phenomenon. Co-selection is thought to have contributed significantly to the increase in
multiple drug resistance. The observation of the verotoxin and the intimin proteins from the
isolates could mean that poultry are potential carriers of human diarrhoeaganic E. coli. Since
the bacteria are pathogenic this is of public health importance. Therefore care should be taken
during processing and production of poultry meat not to pass the pathogenic bacteria to
humans.
Description
Department of Plant and Microbial Sciences, 74p. The SF 809 .E82O34 2009
Keywords
Escherichia coli infections in animals, Antibiotics in nutrition