Thakur Siddhartha, Gebreyes Wondwossen A
Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.
J Food Prot. 2005 Nov;68(11):2402-10. doi: 10.4315/0362-028x-68.11.2402.
The objectives of this study were to determine and compare the prevalence and antimicrobial resistance of Campylobacter species in swine reared in conventional and antimicrobial-free (ABF) production systems. Campylobacter coli was the predominant species, with 1,459 isolates (99%) in the study. We found significantly higher prevalence of C. coli on the ABF farms (77.3%) than on the conventional farms (27.6%) among pigs at the nursery stage (P < 0.001). At slaughter, we found significantly higher prevalence at the postevisceration than at the preevisceration stage (P < 0.001) in both production systems. The 1,459 C. coli isolates were tested with the agar dilution method for their susceptibility to six antimicrobials: chloramphenicol, ciprofloxacin, erythromycin, gentamicin, nalidixic acid, and tetracycline. Resistance was most prevalent against tetracycline (66.2% of isolates) followed by erythromycin (53.6% of isolates). Frequency of resistance to these two antimicrobials was significantly higher among conventional herds (83.4% for tetracycline and 77% for erythromycin) than among ABF herds (56.2% for tetracycline and 34.5% for erythromycin). Resistance to ciprofloxacin at the MIC (> 4 mg/liter) was also found on farms in both systems. Multidrug-resistant C. coli strains were detected in both the conventional (7%) and ABF (4%) herds. This is the first report of ciprofloxacin-resistant strains of C. coli in ABF pigs in the United States. These findings highlight the high prevalence of antimicrobial-resistant C. coli in both conventional and ABF pig production systems and have significant implications for the persistence of antimicrobial-resistant Campylobacter in the pig production environment regardless of levels of antimicrobial use.
本研究的目的是确定并比较在传统养殖系统和无抗养殖系统中饲养的猪体内弯曲杆菌属的流行率及抗菌药物耐药性。空肠弯曲杆菌是主要菌种，本研究中有1459株分离菌（占99%）。我们发现，在保育阶段的猪中，空肠弯曲杆菌在无抗养殖农场中的流行率（77.3%）显著高于传统养殖农场（27.6%）（P<0.001）。在屠宰时，我们发现，在两个养殖系统中，去内脏后阶段的流行率均显著高于去内脏前阶段（P<0.001）。采用琼脂稀释法对1459株空肠弯曲杆菌分离菌进行了六种抗菌药物敏感性测试，这六种抗菌药物分别为：氯霉素、环丙沙星、红霉素、庆大霉素、萘啶酸和四环素。对四环素的耐药性最为普遍（66.2%的分离菌），其次是红霉素（53.6%的分离菌）。传统猪群中对这两种抗菌药物的耐药频率显著高于无抗养殖猪群（四环素为83.4%，红霉素为77%）（无抗养殖猪群中四环素为56.2%，红霉素为34.5%）。在两个养殖系统的农场中均发现了对环丙沙星的耐药性（最低抑菌浓度>4mg/L）。在传统猪群（7%）和无抗养殖猪群（4%）中均检测到多重耐药空肠弯曲杆菌菌株。这是美国关于无抗养殖猪中耐环丙沙星空肠弯曲杆菌菌株的首次报道。这些发现凸显了空肠弯曲杆菌在传统和无抗养殖猪生产系统中抗菌药物耐药性的高流行率，并且对猪生产环境中耐抗菌药物弯曲杆菌的持续存在具有重要意义，无论抗菌药物的使用水平如何。
