Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Zoonoses Public Health. 2010 Nov;57 Suppl 1:100-6. doi: 10.1111/j.1863-2378.2010.01363.x.
The aim of this study was to determine the phenotypic and genotypic diversity of multiple Campylobacter isolates (n = 3 per sample) present within individual (heterogeneity) pig faecal and carcass samples at farm and slaughter, respectively. We isolated 1459 Campylobacter coli (1110 on farm and 349 from slaughter) from 908 pigs and 757 carcasses and characterized them for their antimicrobial susceptibility profile to a panel of six antimicrobials using the agar dilution method. Overall, we detected a significantly higher Campylobacter prevalence at the farm (54.7%) than at slaughter (19%) level (P < 0.05). C. coli isolates were resistant most commonly to tetracycline (66.2%) and erythromycin (53.6%) while fluoroquinolone resistance was detected in isolates (n = 17) only from the farm level. Phenotypic diversity of C. coli isolates at the 4-fold minimum inhibitory concentration levels within the same sample was detected in 38.6% (n = 192) pigs and 40.2% (n = 58) carcass swabs with no significant difference between the two sources (P = 0.72). Phenotypic heterogeneity based on the antimicrobial resistance patterns was observed in 32.5% (n = 162) of the farm samples and in 30.5% (n = 44) carcass swabs at slaughter (P = 0.64). A subset of 40 isolates representing ten pigs and eight carcass samples (originating from separate pigs) were further genotyped by multi locus sequence typing. The observation of phenotypic diversity was replicated at the genotypic level, as it was highlighted by the 22 sequence types which represented the 40 isolates. In conclusion, we detected multiple C. coli subtypes from individual pig or carcass samples indicating unprecedented level of heterogeneity. Our study clearly signifies the importance of testing multiple colonies to make appropriate and valid conclusions in epidemiological-based studies.
本研究的目的是确定个体(异质性)猪粪便和屠体样本中存在的多种弯曲杆菌分离株(每个样本 3 个)的表型和基因型多样性。我们从 908 头猪和 757 个屠体中分离出 1459 株大肠弯曲杆菌(农场分离出 1110 株,屠宰场分离出 349 株),并使用琼脂稀释法对 6 种抗菌药物的药敏谱进行了特征分析。总的来说,我们在农场(54.7%)水平上检测到明显更高的弯曲杆菌流行率,而在屠宰场(19%)水平上则较低(P<0.05)。C. coli 分离株最常见的耐药性是对四环素(66.2%)和红霉素(53.6%),而氟喹诺酮类耐药性仅在农场水平的分离株(n=17)中检测到。在同一样本中,4 倍最低抑菌浓度水平下 C. coli 分离株的表型多样性在 38.6%(n=192)头猪和 40.2%(n=58)屠体拭子中检测到,在两个来源之间无显著差异(P=0.72)。在 32.5%(n=162)个农场样本和 30.5%(n=44)个屠宰场屠体拭子中观察到基于抗菌药物耐药模式的表型异质性(P=0.64)。从 10 头猪和 8 个屠体样本(来自不同的猪)中选取了 40 个分离株的亚群进行多位点序列分型。表型多样性的观察结果在基因型水平上得到了复制,因为这 40 个分离株代表了 22 个序列类型。总之,我们从单个猪或屠体样本中检测到多种 C. coli 亚型,表明存在前所未有的异质性。我们的研究清楚地表明,在基于流行病学的研究中,需要对多个菌落进行测试,以得出适当和有效的结论。