Survey of Non-typhoid Salmonella Infections among some Broiler Flocks of Mazandaran and Gilan Provinces, 2010-2015

Non-typhoid Salmonella spp. are recognized as one of the major food-borne pathogens with more than 2500 serotypes worldwide. This survey was done to determine Salmonella infection among broiler flocks in Mazandaran and Gilan Provinces, as among the most important poultry production centers in Iran. Thirty-five Salmonella isolates were recovered by standard bacteriological methods from 13310 manure samples (1331 pooled samples) collected from 126 broiler houses in different ages. Slide agglutination tests were performed using Salmonella somatic O poly antisera form each of A to E antisera. The occurrence rate of infection was 26% among 126 houses. It was found that 17 (48.57%) and 18 (51.43%) isolates belonged to groups D and C, respectively. The occurrence and the level of antimicrobial resistance patterns in 35 Salmonella isolates were also determined. Thirty-two different patterns of resistance were found among 35 isolates. The highest resistance was observed to erythromycin, vancomycin, clindamycin, penicillin, doxycycline, colistin, oxytetracycline, carbenicillin, furazolidone and tetracycline. The highest percentage of sensitivity (100%) was found to ceftriaxon, danofloxacin, levofloxacin, imipenem, ofloxacin, cefazolin and amoxicillin. All isolates were found to be multi-resistance. In the other words, all isolates were resistant against one to three antimicrobials tested. The high prevalence of multidrug resistance found in this study may be attributed to widespread usage of antimicrobial agents in domestic animals especially poultry industry in Iran. There is a serious implication for public health by transmitting resistant bacteria to human via food chain.