Ali Syed Abid, Bin-Asif Hassan, Hasan Khwaja Ali, Rehman Marium, Abbasi Atiya
H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan.
Microb Pathog. 2017 Apr;105:298-306. doi: 10.1016/j.micpath.2017.02.041. Epub 2017 Feb 28.
Enterococci, no more regarded as GRAS (Generally Recognized As Safe) organism, are emerging as an important source of nosocomial infections worldwide. The main contributors in pathogenesis of enterococci are the presence of various virulent factors and antibiotic resistance genes. We aimed to examine the prevalence, dissemination, antibiotic resistance and virulent factors associated with enterococci from bulk soil (BS). A total of 372 enterococci were isolated from 500 soil samples. PCR was used to identify the isolates up to species level and for carriage of 16 virulence genes including hospital associated marker (i.e. IS16). E. faecium (77%), E. faecalis (10%), E. hirae (4%) and E. casseliflavus (1%) were the major species isolated. The efaAfs was the most dominant gene (100%), followed by gelE (78.9%), sprE (76.3%) and esp (13%) in E. faecalis isolates. The E. faecium carried largely efaAfm (86.8%) and acm (50.3%) genes. Presence of entP (10%), entA (8.3%) and entB (6.9%) genes was detected mostly in E. faecium, while enlA (18%) and ef1097 (2.6%) was only detected in E. faecalis isolates. 50% E. faecalis and 2% E. faecium isolates harbored IS16, while five E. faecalis harbored both IS16 and espTIM genes providing strong evidence about the presence of espTIM gene on 64 Kb pathogenicity island. BOX and RAPD PCR analysis revealed high degree of genetic variation within the species. Degree of resistance against 12 major antibiotics showed chloramphenicol as the most effective and meropenom as the least effective antibiotic. Presence of multiple antibiotic resistant, virulent and hospital associated enterococci in bulk soil represents a potential source for further dissemination to humans and animals and poses potential impact on public health.
肠球菌不再被视为一般认为安全的微生物，正成为全球医院感染的重要来源。肠球菌发病机制的主要促成因素是各种毒力因子和抗生素抗性基因的存在。我们旨在检测来自大量土壤（BS）的肠球菌的流行率、传播情况、抗生素抗性和毒力因子。从500份土壤样本中总共分离出372株肠球菌。采用聚合酶链反应（PCR）将分离株鉴定到种水平，并检测16种毒力基因的携带情况，包括医院相关标记物（即IS16）。分离出的主要菌种为屎肠球菌（77%）、粪肠球菌（10%）、海氏肠球菌（4%）和鹑鸡肠球菌（1%）。在粪肠球菌分离株中，efaAfs是最主要的基因（100%），其次是gelE（78.9%）、sprE（76.3%）和esp（13%）。屎肠球菌主要携带efaAfm（86.8%）和acm（50.3%）基因。entP（10%）、entA（8.3%）和entB（6.9%）基因主要在屎肠球菌中检测到，而enlA（18%）和ef1097（2.6%）仅在粪肠球菌分离株中检测到。50%的粪肠球菌分离株和2%的屎肠球菌分离株携带IS16，而五株粪肠球菌同时携带IS16和espTIM基因，有力证明了espTIM基因存在于64kb的致病岛上。BOX和随机扩增多态性DNA（RAPD）PCR分析显示该菌种内存在高度的遗传变异。对12种主要抗生素的耐药程度表明，氯霉素是最有效的抗生素，而美罗培南是最无效的抗生素。大量土壤中存在多重耐药、有毒力且与医院相关的肠球菌，这是进一步传播给人类和动物的潜在来源，并对公众健康构成潜在影响。
