Hassan Manal I, Alkharsah Khaled R, Alzahrani Alhusain J, Obeid Obeid E, Khamis Amar H, Diab Asim
Department of Microbiology and Immunology, Faculty of Medicine, Alexandria University, Egypt.
J Infect Dev Ctries. 2013 Aug 15;7(8):618-29. doi: 10.3855/jidc.2919.
Few reports about the prevalence and genetic basis of extended spectrum beta-lactamases (ESBLs) are available from Saudi Arabia. We sought to determine the prevalence of ESBL-producing Enterobacteriaceae in a university hospital in eastern Saudi Arabia and to characterize the ESBLs produced by these isolates at the molecular level.
All clinical isolates of Escherichia coli, Klebsiella spp., and Proteus spp. collected over two years were evaluated for susceptibility to a panel of antimicrobials and were analyzed for the ESBL phenotype using screening and confirmatory tests. ESBL-positive isolates were then screened for the presence of genes encoding CTX-M, SHV, and TEM beta-lactamases by PCR.
The overall prevalence of ESBL-producing isolates was 4.8% (253/5256). Most isolates (80%) were from the inpatient department. The ESBL phenotype was more frequently detected in K. pneumonia. CTX-M genes were the most prevalent ESBL genes, detected in 82% of the studied isolates. The ESBL producers demonstrated a high multidrug resistance rate (96.6%). In transconjugation assay, the same ESBL gene pattern was transmitted from 29.7% of K. pneumoniae donors to the recipient strain, and the latter exhibited concomitant decreased aminoglycosides and co-trimoxazole susceptibility. We observed the presence of ESBL screen-positive but confirmatory-negative isolates (8.9%). Phenotypic tests for the production of AmpC β-lactamase tested positive in 52% of these isolates. Further studies are needed for appropriate detection of concomitant ESBL and AmpC enzyme production among such isolates. Continued surveillance and judicious antibiotic usage together with the implementation of efficient infection control measures are absolutely required.
沙特阿拉伯关于超广谱β-内酰胺酶（ESBLs）的流行情况和遗传基础的报道较少。我们试图确定沙特阿拉伯东部一家大学医院中产ESBL肠杆菌科细菌的流行情况，并在分子水平上对这些分离株产生的ESBLs进行特征分析。
对两年内收集的所有大肠埃希菌、克雷伯菌属和变形杆菌属临床分离株进行一组抗菌药物的敏感性评估，并使用筛选和确证试验分析其ESBL表型。然后通过PCR对ESBL阳性分离株进行编码CTX-M、SHV和TEMβ-内酰胺酶基因的筛选。
产ESBL分离株的总体流行率为4.8%（253/5256）。大多数分离株（80%）来自住院部。ESBL表型在肺炎克雷伯菌中更常被检测到。CTX-M基因是最常见的ESBL基因，在82%的研究分离株中被检测到。产ESBL菌株表现出较高的多重耐药率（96.6%）。在接合转移试验中，29.7%的肺炎克雷伯菌供体的相同ESBL基因模式传递给了受体菌株，后者同时表现出对氨基糖苷类和复方新诺明敏感性降低。我们观察到存在ESBL筛选阳性但确证阴性的分离株（8.9%）。这些分离株中52%的AmpCβ-内酰胺酶产生的表型试验呈阳性。需要进一步研究以适当检测此类分离株中ESBL和AmpC酶的同时产生。持续监测和合理使用抗生素以及实施有效的感染控制措施是绝对必要的。
