Blanco J E, Blanco M, Alonso M P, Mora A, Dahbi G, Coira M A, Blanco J
Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), 27002 Lugo, Spain.
J Clin Microbiol. 2004 Jan;42(1):311-9. doi: 10.1128/JCM.42.1.311-319.2004.
We have analyzed the prevalence of Shiga toxin-producing Escherichia coli (STEC) in stool specimens of patients with diarrhea or other gastrointestinal alterations from the Xeral-Calde Hospital of Lugo City (Spain). STEC strains were detected in 126 (2.5%) of 5,054 cases investigated, with a progressive increase in the incidence from 0% in 1992 to 4.4% in 1999. STEC O157:H7 was isolated in 24 cases (0.5%), whereas non-O157 STEC strains were isolated from 87 patients (1.7%). STEC strains were (after Salmonella and Campylobacter strains) the third most frequently recovered enteropathogenic bacteria. A total of 126 human STEC isolates were characterized in this study. PCR showed that 43 (34%) isolates carried stx(1) genes, 45 (36%) possessed stx(2) genes and 38 (30%) carried both stx(1) and stx(2). A total of 88 (70%) isolates carried an ehxA enterohemolysin gene, and 70 (56%) isolates possessed an eae intimin gene (27 isolates with type gamma1, 20 with type beta1, 8 with type zeta, 5 with type gamma2, and 3 with type epsilon). STEC isolates belonged to 41 O serogroups and 66 O:H serotypes, including 21 serotypes associated with hemolytic uremic syndrome and 30 new serotypes not previously reported among human STEC strains in other studies. Although the 126 STEC isolates belonged to 81 different seropathotypes (associations between serotypes and virulence genes), only four accounted for 31% of isolates. Seropathotype O157:H7 stx(1) stx(2) eae-gamma1 ehxA was the most common (13 isolates) followed by O157:H7 stx(2) eae-gamma1 ehxA (11 isolates), O26:H11 stx(1) eae-beta1 ehxA (11 isolates), and O111:H- stx(1) stx(2) eae-gamma2 ehxA (4 isolates). Our results suggest that STEC strains are a significant cause of human infections in Spain and confirm that in continental Europe, infections caused by STEC non-O157 strains are more common than those caused by O157:H7 isolates. The high prevalence of STEC strains (both O157:H7 and non-O157 strains) in human patients, and their association with serious complications, strongly supports the utilization of protocols for detection of all serotypes of STEC in Spanish clinical microbiology laboratories.
我们分析了西班牙卢戈市塞拉尔 - 卡尔德医院腹泻或有其他胃肠道病变患者粪便标本中产志贺毒素大肠杆菌（STEC）的流行情况。在所调查的5054例病例中，126例（2.5%）检测到STEC菌株，发病率从1992年的0%逐渐上升至1999年的4.4%。24例（0.5%）分离出STEC O157:H7，而87例患者（1.7%）分离出非O157 STEC菌株。STEC菌株（仅次于沙门氏菌和弯曲杆菌菌株）是第三大最常分离出的肠道致病菌。本研究共鉴定了126株人源STEC分离株。聚合酶链反应（PCR）显示，43株（34%）分离株携带stx(1)基因，45株（36%）拥有stx(2)基因，38株（30%）同时携带stx(1)和stx(2)。共有88株（70%）分离株携带ehxA肠溶血素基因，70株（56%）分离株拥有eae紧密素基因（27株为γ1型，20株为β1型，8株为ζ型，5株为γ2型，3株为ε型）。STEC分离株属于41个O血清群和66个O:H血清型，包括21个与溶血尿毒综合征相关的血清型以及30个其他研究中未在人源STEC菌株中报道过的新血清型。尽管这126株STEC分离株属于81种不同的血清致病型（血清型与毒力基因之间的关联），但仅4种占分离株的31%。血清致病型O157:H7 stx(1) stx(2) eae - γ1 ehxA最为常见（13株），其次是O157:H7 stx(2) eae - γ1 ehxA（11株）、O26:H11 stx(1) eae - β1 ehxA（11株）和O111:H - stx(1) stx(2) eae - γ2 ehxA（4株）。我们的结果表明，STEC菌株是西班牙人类感染的重要原因，并证实在欧洲大陆，由STEC非O157菌株引起的感染比O157:H7分离株引起的感染更为常见。STEC菌株（O157:H7和非O157菌株）在人类患者中的高流行率及其与严重并发症的关联，有力支持了西班牙临床微生物实验室采用检测所有STEC血清型的方案。
