Applied Sciences Faculty, Cape Peninsula University of Technology, Cape Town, South Africa.
J Microbiol Biotechnol. 2012 Jan;22(1):25-33. doi: 10.4014/jmb.1107.07029.
The association of verotoxic E. coli and Acinetobacter spp. with various antibiotic-resistant, diarrhogenic, and nosocomial infections has been a cause for concern worldwide. E. coli and A. haemolyticus isolated on a number of selective media were screened for virulence factors, antibiotic resistance, and transformation of resistance genes. Out of 69 E. coli isolates obtained, 25 (35.23%), 14 (20.30%), and 28 (40.58%) were positive for Vtx1&2, Vtx1, and Vtx2, respectively, 49 (71.015%) for extendedspectrum beta-lactamases (ESBLs), 34 (49.28%) for serum resistance, 57 (82.61%) for cell surface hydrophobicity, 48 (69.57%) for gelatinase production, and 37 (53.62%) for hemolysin production. For the 14 A. haemolyticus isolates, only 2 (14.29%) in each case from all the samples investigated were positive for Vtx1, Vtx2 and Vtx1&2 respectively, 8 (57.14%) for ESBLs, 7 (50.00%) for serum resistance, 11 (78.57%) for cell surface hydrophobicity, 4 (28.57%) for gelatinase production, and 8 (57.14%) for hemolysin production. Although transformation occurred among the E. coli and Acinetobacter isolates (transformation frequency: 13.3 × 10(-7) -53.4(-7)), there was poor curing of the plasmid genes, a confirmation of the presence of stable antibiotic-resistant genes (DNA concentration between 42.7 and 123.8 microgram) and intragenetic transfer of multidrugresistant genes among the isolates. The isolates were potentially virulent and contained potentially transferable antibiotic resistance genes. Detection of virulence factors, antibiotic resistance genes, and transformation among these isolates is a very significant outcome that will influence approaches to proactive preventive and control measures and future investigations. However, continued surveillance for drug resistance among these bacteria and further investigation of the mechanism of action of their virulence factors are a necessity.
产志贺毒素大肠埃希氏菌和不动杆菌属与各种抗生素耐药、腹泻和医院感染的关联已成为全球关注的问题。在多种选择性培养基上分离的大肠埃希氏菌和溶血不动杆菌被筛选出毒力因子、抗生素耐药性和耐药基因的转化。从 69 株大肠埃希氏菌分离株中，分别有 25 株（35.23%）、14 株（20.30%）和 28 株（40.58%）对 Vtx1&2、Vtx1 和 Vtx2 呈阳性，49 株（71.015%）对扩展型β-内酰胺酶（ESBLs）、34 株（49.28%）对血清抗性、57 株（82.61%）对细胞表面疏水性、48 株（69.57%）对明胶酶产生、37 株（53.62%）对溶血素产生呈阳性。对于 14 株溶血不动杆菌分离株，仅在调查的所有样本中各有 2 株（14.29%）分别对 Vtx1、Vtx2 和 Vtx1&2 呈阳性，8 株（57.14%）对 ESBLs、7 株（50.00%）对血清抗性、11 株（78.57%）对细胞表面疏水性、4 株（28.57%）对明胶酶产生、8 株（57.14%）对溶血素产生呈阳性。尽管在大肠埃希氏菌和不动杆菌分离株之间发生了转化（转化频率：13.3×10(-7)-53.4(-7)），但质粒基因的治愈率很差，这证实了稳定的抗生素耐药基因的存在（DNA 浓度在 42.7 和 123.8 微克之间），以及在分离株之间多药耐药基因的基因内转移。这些分离株具有潜在的毒力，并含有潜在的可转移抗生素耐药基因。这些分离株中检测到毒力因子、抗生素耐药基因和转化，这是一个非常重要的结果，将影响主动预防和控制措施的方法和未来的研究。然而，有必要继续监测这些细菌的耐药性，并进一步研究其毒力因子的作用机制。
