Lactic acid bacteria (LAB) are heterogeneous group of bacteria which are fastidious in
nature. LAB has acquired status as Generally-Recognized-as-Safe (GRAS) status. Over-use and
misuse of antibiotics in veterinary and human clinical setups give rise to antibiotic resistant lactic
acid bacteria in gastrointestinal tracts which act as antibiotic resistance reservoir. Acquired and
transferable antibiotic resistance in lactic acid bacteria is a newly identified safety concern in
poultry. So, it is dire need of time to determine the situation of antibiotic resistance in lactic acid
bacteria of poultry gastrointestinal tract (GIT).
The present study was conducted to isolate lactobacilli from indigenous and broiler
gastrointestinal tract of chicken. For this purpose, chicken feces, cloaca and caecum samples
(n=20 each) were collected from Lahore. Lactic acid bacteria were isolated on MRS medium.
Isolates were identified by phenotypic characteristics including Colonial morphology, Gram
staining and Catalase test. While molecular identification of lactobacillus spp. was done by PCR
at an annealing temperature of 55°C using the primers XB-5 and LbLMA-1 with an expected
product size of 250bp. Minimum inhibitory concentrations of different antibiotics such as
ampicillin, erythromycin, tetracycline, ciprofloxacin, cephradine, cefuroxime, ofloxacin,
levofloxacin were determined by the broth micro dilution method following the EFSA
guidelines. Antibiotic resistance genes, including erythromycin arm (B) and tetracycline Tet (M)
were amplified by polymerase chain reaction.
The comparison of % antibiotic resistance pattern between broiler and indigenous
lactobacillus spp. against different antibiotics was analysed for chi-square test using SPSS
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version 16.0. The study provided data on antibiotic resistance pattern of transferable resistance
genes in lactic acid bacteria of poultry gut.
Conclusion:
From the present study it is concluded that a high level of resistance was shown by lactobacillus
spp. against tested antibiotics. Lactobacillus spp. were screened by PCR for known resistance
genes and thus were able to determine the presence of erm(B) and tet (M) genes in all
lactobacillus spp. using erm(B) and tet (M)-specific primers. All lactobacillus spp. were also
phenotypically resistant to erythromycin and tetracycline. Thus, the present study indicates that
such erm (B) and Tet (M) genes occur among different LAB genera and species therefore it is
the need of time to study other resistance determinants to ensure the safety of poultry meat and
spread of resistance determinants.