scholarly journals Rapid Identification and Differentiation of Clinical Isolates of Enteropathogenic Escherichia coli (EPEC), Atypical EPEC, and Shiga Toxin-Producing Escherichia coli by a One-Step Multiplex PCR Method

2006 ◽  
Vol 44 (7) ◽  
pp. 2626-2629 ◽  
Author(s):  
D. Muller ◽  
P. Hagedorn ◽  
S. Brast ◽  
G. Heusipp ◽  
M. Bielaszewska ◽  
...  
2021 ◽  
pp. 103926
Author(s):  
Omar Hernández Hernández ◽  
Ana L. Gutiérrez-Escolano ◽  
Cleo Cancio-Lonches ◽  
Montserrat H. Iturriaga ◽  
Juan Ramiro Pacheco-Aguilar ◽  
...  

2008 ◽  
Vol 74 (18) ◽  
pp. 5645-5652 ◽  
Author(s):  
Jie Zheng ◽  
Shenghui Cui ◽  
Louise D. Teel ◽  
Shaohua Zhao ◽  
Ruby Singh ◽  
...  

ABSTRACT There is considerable heterogeneity among the Shiga toxin type 2 (Stx2) toxins elaborated by Shiga toxin-producing Escherichia coli (STEC). One such Stx2 variant, the Stx2d mucus-activatable toxin (Stx2dact), is rendered more toxic by the action of elastase present in intestinal mucus, which cleaves the last two amino acids of the A2 portion of the toxin A subunit. We screened 153 STEC isolates from food, animals, and humans for the gene encoding Stx2dact by using a novel one-step PCR procedure. This method targeted the region of stx 2dact that encodes the elastase recognition site. The presence of stx 2dact was confirmed by DNA sequencing of the complete toxin genes. Seven STEC isolates from cows (four isolates), meat (two isolates), and a human (one isolate) that carried the putative stx 2dact gene were identified; all were eae negative, and none was the O157:H7 serotype. Three of the isolates (CVM9322, CVM9557, and CVM9584) also carried stx 1, two (P1332 and P1334) carried stx 1 and stx 2c, and one (CL-15) carried stx 2c. One isolate, P1130, harbored only stx 2dact. The Vero cell cytotoxicities of supernatants from P1130 and stx 1 deletion mutants of CVM9322, CVM9557, and CVM9584 were increased 13- to 30-fold after treatment with porcine elastase. Thus, Stx2dact-producing strains, as detected by our one-step PCR method, can be isolated not only from humans, as previously documented, but also from food and animals. The latter finding has important public health implications based on a recent report from Europe of a link between disease severity and infection with STEC isolates that produce Stx2dact.


2018 ◽  
Vol 9 ◽  
Author(s):  
Rosely Martins Gioia-Di Chiacchio ◽  
Marcos Paulo Vieira Cunha ◽  
Lilian Rose Marques de Sá ◽  
Yamê Minieiro Davies ◽  
Camila Bueno Pacheco Pereira ◽  
...  

2007 ◽  
Vol 56 (5) ◽  
pp. 620-628 ◽  
Author(s):  
Matthew W. Gilmour ◽  
Adam B. Olson ◽  
Ashleigh K. Andrysiak ◽  
Lai-King Ng ◽  
Linda Chui

Serogroup classifications based upon the O-somatic antigen of Shiga toxin-producing Escherichia coli (STEC) provide significant epidemiological information on clinical isolates. Each O-antigen determinant is encoded by a unique cluster of genes present between the gnd and galF chromosomal genes. Alternatively, serogroup-specific polymorphisms might be encoded in loci that are encoded outside of the O-antigen gene cluster. Segments of the core bacterial loci mdh, gnd, gcl, ppk, metA, ftsZ, relA and metG for 30 O26 STEC strains have previously been sequenced, and comparative analyses to O157 distinguished these two serogroups. To screen these loci for serogroup-specific traits within a broader range of clinically significant serogroups, DNA sequences were obtained for 19 strains of 10 additional STEC serogroups. Unique alleles were observed at the gnd locus for each examined STEC serogroup, and this correlation persisted when comparative analyses were extended to 144 gnd sequences from 26 O-serogroups (comprising 42 O : H-serotypes). These included O157, O121, O103, O26, O5 : non-motile (NM), O145 : NM, O113 : H21, O111 : NM and O117 : H7 STEC; and furthermore, non-toxin encoding O157, O26, O55, O6 and O117 strains encoded distinct gnd alleles compared to STEC strains of the same serogroup. DNA sequencing of a 643 bp region of gnd was, therefore, sufficient to minimally determine the O-antigen of STEC through molecular means, and the location of gnd next to the O-antigen gene cluster offered additional support for the co-inheritance of these determinants. The gnd DNA sequence-based serogrouping method could improve the typing capabilities for STEC in clinical laboratories, and was used successfully to characterize O121 : H19, O26 : H11 and O177 : NM clinical isolates prior to serological confirmation during outbreak investigations.


2007 ◽  
Vol 56 (9) ◽  
pp. 1185-1188 ◽  
Author(s):  
Cícero A. Dias ◽  
Lúcia Martins Teixeira ◽  
Maria da Glória Carvalho ◽  
Bernard Beall

Capsular serotype surveillance of clinical isolates of Streptococcus pneumoniae is essential for evaluation of the potential impact of introducing multivalent capsular serotype-based vaccines in Latin America. Here, a previously described sequential multiplex PCR method was revised for optimal targeting of prevalent serotypes in Latin America. The revised protocol successfully serotyped 139/147 pneumococci (94.6 %) from Brazilian children, demonstrating a labour-efficient, accurate method requiring only conventional PCR capability.


2010 ◽  
Vol 59 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Vaida Šeputienė ◽  
Justas Povilonis ◽  
Modestas Ružauskas ◽  
Alvydas Pavilonis ◽  
Edita Sužiedėlienė

A total of 456 non-repetitive Escherichia coli isolates from human clinical specimens (urinary, n=134; cervix, vagina and prostate, n=52; blood, pus and wounds, n=45), healthy animals (cattle, n=45; poultry, n=20) and diseased animals (cattle, n=53; swine, n=64; poultry, n=43) obtained in Lithuania during the period 2005–2008 were studied for trimethoprim (TMP) resistance and the prevalence of dfr genes. A TMP resistance rate in the range of 18–26 % respective to the origin was found in clinical isolates, 23–40 % in isolates from diseased animals and 9–20 % in isolates from healthy animals. Of 112 TMP-resistant isolates, 103 carried at least one of the six dfrA genes (dfrA1, dfrA5, dfrA8, dfrA12, dfrA14 and dfrA17) as determined by multiplex PCR and RFLP. The dfrA1 and dfrA17 genes were found most frequently in clinical isolates (17 and 19 isolates, respectively), whilst dfrA1 and dfrA14 genes dominated in isolates of animal origin (25 and 13 isolates, respectively). The dfrA5, dfrA12 and dfrA8 genes were detected at lower frequencies. The association with class 1/class 2 integrons was confirmed for 73–100 % of dfr genes found in most groups of isolates, except for the isolates from diseased swine. In this group, the majority of dfr-positive isolates (67 %, 8/12) carried dfrA8 (6/12) or dfrA14 genes (2/12) that were not associated with integrons. Non-integron location was also confirmed for the remaining dfrA8 genes (six clinical isolates and one isolate from diseased cattle) and for dfrA14 genes (two isolates from diseased cattle and swine each). All cassette-independent dfrA14 genes were found to be located within the strA gene. This study on the prevalence and distribution of TMP resistance genes among E. coli isolates of human and animal origin in Lithuania demonstrates that dfr genes are carried most frequently as gene cassettes within class 1 and/or class 2 integrons. However, TMP resistance in some of the isolates was found to be mediated by non-integron-associated dfrA8 and dfrA14 genes, indicating the existence of alternative sources for the spread of resistance.


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