Prevalence of antibiotic-resistant E. coli in broilers challenged with a multi-resistant E. coli strain and received ampicillin, an organic acid-based feed additive or a synbiotic preparation (original) (raw)
Information on the level to which commercial feeds and feed raw materials are involved in the dissemination o anti-microbial resistant pathogenic and commensal bacteria in Nigeria is necessary for feed and stock management. Forty four Escherichia coli isolates from 4 commercial feed brands coded SF, GF, TF and ACF and from 90 various feed raw materials such, f sh meal (FM), maize (MA), maize offal (MO), wheat offal (WO), spent grain (SG), blood meal (BM) and soybean meal (SM) etc were screened for anti-microbial resistance profile against 10 antibiotics using the d sc d fusion method. Overall, the isolates recorded 80.8 % resistance to cefuroxime, 76.9 % to nalidixic acid, 75 % to ampicillin, and 59 6 % to cotrimoxazole while very low 7 7 % was recorded for tetracycline and 5 8 % for gentamycin, ciprofloxacin and chloramphenicol. Across commercial feed brands, isolates from SF were resistant to nitrofurantoin (100 %), nalidixic acid (50 %) and ampicillin (70 %), while those from TF, GF and ACF were resistant to 7 6 and 5 antibiotics respectively. Resistance against ampicillin, nalidixic acid and cefuroxime, in isolates from SG, palm kernel cake (PK), MO and WO were high. Organisms iso ated from SG and PK recorded high resistance against cefuroxime and cotrimoxazole. Isolates from bone/limestone (B/L) reg stered 100 % resistance against ampicillin, cotrimoxazole and cefuroxime, while those from maize MA recorded 100 % resistance to cefuroxime and norfloxacin, and over 70 % to nalidixic acid. Soybean meal isolates values for nitrofurantoin, tetracycline, nalidixic acid and ampicillin were high but below 80 %. Thirty fives resistance patterns were observed; w th the CF-NB-CO-NA-AM pattern being the most predominant (occurring 10 times). The present data shows that commercial feeds and feed raw materials are important vehicles for the introduction of mult-drug resistance encoding E coli into poultry.
Antibiotics
The spread of resistant bacteria from livestock to the food industry promoted an increase of alternative poultry production systems, such as organic and antibiotic-free ones, based on the lack of antimicrobial use, except in cases in which welfare is compromised. We aimed to investigate the antibiotic susceptibility of commensal Escherichia coli isolated from organic, antibiotic-free, and conventional broiler farms and slaughterhouses toward several antimicrobials critically important for human health. To assess antimicrobial susceptibility, all E. coli isolates and extended spectrum beta-lactamase (ESBL) E. coli were analysed by the microdilution method. The prevalence of tigecycline, azithromycin and gentamicin E. coli-resistant strains was highest in organic samplings. Conversely, the lowest prevalence of resistant E. coli strains was observed for cefotaxime, ceftazidime and ciprofloxacin in organic systems, representing a significant protective factor compared to conventional sy...