Isolation, molecular typing and antibiotic sensitivity profiling of enteric bacterial pathogen from chicken eggs

Abstract

Food is a basic need of life; nevertheless its contamination due to pathogenic bacteria, especially antibiotic-resistant bacteria (ARB) in the poultry world, is a big threat to public health. In this study, enteric bacteria were isolated from chicken eggs and their antibiotic resistance against a panel of 18 different antibiotics belonging to 09 different antibiotic classes was determined. A total of 300 egg samples (i.e. 150 egg shells and 150 egg interiors) were collected and evaluated for bacterial growth. It was observed that 46% of the samples (n = 138) were positive for the growth of bacteria, while 54% of the samples (n = 162) did not show any bacterial growth in specified culture conditions. From those growth positive samples, three genera of Salmonella (from both the egg shell and the egg interior) and a genus of Enterobacter species, i.e. Enterobacter spp. (only from egg shells), were isolated using enrichment techniques and identified on the basis of cultural, morphological, biochemical, and 16S rRNA gene sequencing characteristics. The antibiotic sensitivity profiling results revealed that 50% of the isolated Enterobacter species were only resistant to amoxycillin, azomax (azithromycin), and fosfomycin, while 100% resistant to cephalothin, cefuroxime sodium, erythromycin, and vancomycin. On the other hand, 50% of the isolated species of Salmonella were resistant to amoxycillin, urixin, fosfomycin, and amoxycillin, whereas all Salmonella spp. were completely resistant to cephalothin, cefuroxime sodium, erythromycin, vancomycin, moxifloxacin, and azomax (azithromycin). The findings of the current study would increase the awareness of ordinary people to understand and overcome the associated risks associated with the utilization of contaminated eggs or other food products.