Shiga toxin 2-producing Acinetobacter haemolyticus associated with a case of bloody diarrhea.
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ABSTRACT:
SUBMITTER: Grotiuz G
PROVIDER: S-EPMC1594762 | biostudies-literature | 2006 Oct
REPOSITORIES: biostudies-literature
Publications
Shiga toxin 2-producing Acinetobacter haemolyticus associated with a case of bloody diarrhea.
Grotiuz Germán G Sirok Alfredo A Gadea Pilar P Varela Gustavo G Schelotto Felipe F
Journal of clinical microbiology 20061001 10
We report the first Shiga toxin 2-producing Acinetobacter haemolyticus strain that was isolated from the feces of a 3-month-old infant with bloody diarrhea. Usual enteropathogenic bacteria were not detected. This finding suggests that any Shiga toxin-producing microorganism capable of colonizing the human gut may have the potential to cause illness. ...[more]
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Project description:ObjectivesChildren with acute bloody diarrhea are at risk of being infected with Shiga toxin-producing Escherichia coli (STEC) and of progression to hemolytic uremic syndrome. Our objective was to identify clinical and laboratory factors associated with STEC infection in children who present with acute bloody diarrhea.MethodsWe performed a prospective cohort study of consecutive children younger than 18 years who presented with acute (<2-week duration) bloody diarrhea between August 1, 2013, and August 1, 2014. We excluded patients with a chronic gastrointestinal illness and/or an obvious noninfectious source of bloody stool. We obtained a standardized history and study laboratory tests, performed physical examinations, and recorded patient outcomes.ResultsOf the 135 eligible patients, 108 were enrolled; 27 declined consent. The median patient age was 3 years, and 56% were male. Ten (9%) patients tested positive for STEC (E coli O157:H7, n = 8; E coli O111, n = 1; E coli O103, n = 1), and 62 had negative stool culture results. Children infected with STEC were older (8.5 vs 3 years, respectively) (P < .001) and more likely to have abdominal tenderness (83% vs 17%, respectively) than those in the other groups. D-Dimer concentrations had a 70% sensitivity and 55% specificity for differentiating children with STEC from those with another cause of bloody diarrhea and 75% sensitivity and 70% specificity in differentiating children with a bacterial etiology from those with negative stool culture results.ConclusionClinical assessment and laboratory data cannot reliably exclude the possibility that children with bloody diarrhea have an STEC infection and are at consequent risk of developing hemolytic uremic syndrome. Abnormal D-dimer concentrations (>0.5 ?g/mL) were insufficiently sensitive and specific for distinguishing patients with STEC from those with another bacterial cause of bloody diarrhea. However, this marker might be useful in identifying children whose bloody diarrhea is caused by a bacterial enteric pathogen.
| S-EPMC6097574 | biostudies-literature
Project description:Shiga toxin-producing Escherichia coli (STEC) infections result in a significant public health impact because of the severity of the disease that, in young children especially, can lead to hemolytic-uremic syndrome (HUS). A rise in the number of HUS cases was observed in the Apulia region of Italy from 2013 to 2017, and so, in 2018, a symptom-based surveillance system for children with bloody diarrhea (BD) was initiated in order to detect and manage STEC infections. The objective of the study was to describe the epidemiology of STEC infections in children from June 2018 to August 2019. Children <15 years old with BD were hospitalized and tested for STEC. Real-time PCR for virulence genes (stx1, stx2, eae) and serogroup identification tests were performed on stool samples/rectal swabs of cases. STEC infection was detected in 87 (10.6%) BD cases. The median age of STEC cases was 2.7 years, and 60 (68.9%) were <4. Of these 87 cases, 12 (13.8%) came from households with diarrhea. The reporting rate was 14.2/100,000, with the highest incidence in cases from the province of Bari (24.2/100,000). Serogroups O26 and O111 were both detected in 22/87 (25.3%) cases. Co-infections occurred in 12.6% of cases (11/87). Twenty-nine STEC were positive for stx1, stx2, and eae. Five cases (5.7%) caused by O26 (n = 2), O111 (n = 2), and O45 (n = 1) developed into HUS. A risk-oriented approach based on the testing of children with BD during the summer may represent a potentially beneficial option to improve the sensitivity of STEC surveillance, not only in Italy but also in the context of Europe as a whole.
| S-EPMC7400587 | biostudies-literature
Project description:BACKGROUND:In 2016, a multijurisdictional team investigated an outbreak of Shiga toxin-producing Escherichia coli (STEC) serogroup O121 and O26 infections linked to contaminated flour from a large domestic producer. METHODS:A case was defined as infection with an outbreak strain in which illness onset was between December 21, 2015, and September 5, 2016. To identify exposures associated with the outbreak, outbreak cases were compared with non-STEC enteric illness cases, matched according to age group, sex, and state of residence. Products suspected to be related to the outbreak were collected for STEC testing, and a common point of contamination was sought. Whole-genome sequencing was performed on isolates from clinical and food samples. RESULTS:A total of 56 cases were identified in 24 states. Univariable exact conditional logistic-regression models of 22 matched sets showed that infection was significantly associated with the use of one brand of flour (odds ratio, 21.04; 95% confidence interval [CI], 4.69 to 94.37) and with tasting unbaked homemade dough or batter (odds ratio, 36.02; 95% CI, 4.63 to 280.17). Laboratory testing isolated the outbreak strains from flour samples, and whole-genome sequencing revealed that the isolates from clinical and food samples were closely related to one another genetically. Trace-back investigation identified a common flour-production facility. CONCLUSIONS:This investigation implicated raw flour as the source of an outbreak of STEC infections. Although it is a low-moisture food, raw flour can be a vehicle for foodborne pathogens.
| S-EPMC5792826 | biostudies-literature
Project description:Two Shiga-like toxin-producing organisms were isolated from the feces of an infant with hemolytic-uremic syndrome by PCR followed by colony blot hybridization. One strain was identified as Escherichia coli OR:H9, while the other was identified as Enterobacter cloacae. Both isolates were highly cytotoxic for Vero cells, and Southern hybridization analysis of chromosomal DNA indicated that both contained a single slt-II-related gene and that these genes were located on similarly sized restriction fragments. Nucleotide sequence analysis indicated that the toxin encoded by the E. cloacae slt-II-related gene was very similar to Shiga-like toxin II variants from E. coli, differing from the most closely related toxin by 3 residues in the A subunit.
| S-EPMC228823 | biostudies-other
Project description:Enterohemorrhagic Escherichia coli (EHEC), a subgroup of Shiga toxin (Stx)-producing E. coli (STEC), is a leading cause of diarrhea and hemolytic-uremic syndrome (HUS) in humans. However, urinary tract infections (UTIs) caused by this microorganism but not associated with diarrhea have occasionally been reported. We geno- and phenotypically characterized three EHEC isolates obtained from the urine of hospitalized patients suffering from UTIs. These isolates carried typical EHEC virulence markers and belonged to HUS-associated E. coli (HUSEC) clones, but they lacked virulence markers typical of uropathogenic E. coli. One isolate exhibited a localized adherence (LA)-like pattern on T24 urinary bladder epithelial cells. Since the glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) are well-known receptors for Stx but also for P fimbriae, a major virulence factor of extraintestinal pathogenic E. coli (ExPEC), the expression of Gb3Cer and Gb4Cer by T24 cells and in murine urinary bladder tissue was examined by thin-layer chromatography and mass spectrometry. We provide data indicating that Stxs released by the EHEC isolates bind to Gb3Cer and Gb4Cer isolated from T24 cells, which were susceptible to Stx. All three EHEC isolates expressed stx genes upon growth in urine. Two strains were able to cause UTI in a murine infection model and could not be outcompeted in urine in vitro by typical uropathogenic E. coli isolates. Our results indicate that despite the lack of ExPEC virulence markers, EHEC variants may exhibit in certain suitable hosts, e.g., in hospital patients, a uropathogenic potential. The contribution of EHEC virulence factors to uropathogenesis remains to be further investigated.
| S-EPMC4249321 | biostudies-literature
Project description:Background and Aim:Shiga toxin-producing Escherichia coli (STEC) are important pathogens of global significance. STEC are responsible for numerous food-borne outbreaks worldwide and their presence in food is a potential health hazard. The objective of the present study was to determine the incidence of STEC in fresh seafood in Mumbai, India, and to characterize STEC with respect to their virulence determinants. Materials and Methods:A total of 368 E. coli were isolated from 39 fresh seafood samples (18 finfish and 21 shellfish) using culture-based methods. The isolates were screened by polymerase chain reaction (PCR) for the genes commonly associated with STEC. The variant Shiga toxin genes were confirmed by Southern blotting and hybridization followed by DNA sequencing. Results:One or more Shiga toxins genes were detected in 61 isolates. Of 39 samples analyzed, 10 (25.64%) samples harbored STEC. Other virulence genes, namely, eaeA (coding for an intimin) and hlyA (hemolysin A) were detected in 43 and 15 seafood isolates, respectively. The variant stx1 genes from 6 isolates were sequenced, five of which were found to be stx1d variants, while one sequence varied considerably from known stx1 sequences. Southern hybridization and DNA sequence analysis suggested putative Shiga toxin variant genes (stx2) in at least 3 other isolates. Conclusion:The results of this study showed the occurrence of STEC in seafood harboring one or more Shiga toxin genes. The detection of STEC by PCR may be hampered due to the presence of variant genes such as the stx1d in STEC. This is the first report of stx1d gene in STEC isolated from Indian seafood.
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Project description:Similar to ruminants, swine have been shown to be a reservoir for Shiga toxin-producing Escherichia coli (STEC), and pork products have been linked with outbreaks associated with STEC O157 and O111:H-. STEC strains, isolated in a previous study from fecal samples of late-finisher pigs, belonged to a total of 56 serotypes, including O15:H27, O91:H14, and other serogroups previously associated with human illness. The isolates were tested by polymerase chain reaction (PCR) and a high-throughput real-time PCR system to determine the Shiga toxin (Stx) subtype and virulence-associated and putative virulence-associated genes they carried. Select STEC strains were further analyzed using a Minimal Signature E. coli Array Strip. As expected, stx 2e (81%) was the most common Stx variant, followed by stx 1a (14%), stx 2d (3%), and stx 1c (1%). The STEC serogroups that carried stx 2d were O15:H27, O159:H16 and O159:H-. Similar to stx 2a and stx 2c, the stx 2d variant is associated with development of hemorrhagic colitis and hemolytic uremic syndrome, and reports on the presence of this variant in STEC strains isolated from swine are lacking. Moreover, the genes encoding heat stable toxin (estIa) and enteroaggregative E. coli heat stable enterotoxin-1 (astA) were commonly found in 50 and 44% of isolates, respectively. The hemolysin genes, hlyA and ehxA, were both detected in 7% of the swine STEC strains. Although the eae gene was not found, other genes involved in host cell adhesion, including lpfAO113 and paa were detected in more than 50% of swine STEC strains, and a number of strains also carried iha, lpfAO26, lpfAO157, fedA, orfA, and orfB. The present work provides new insights on the distribution of virulence factors among swine STEC strains and shows that swine may carry Stx1a-, Stx2e-, or Stx2d-producing E. coli with virulence gene profiles associated with human infections.
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Project description:Thirty-six Shiga toxin-producing Escherichia coli (STEC) O111:H- strains, 18 of which were isolated from patients with hemolytic-uremic syndrome (HUS) and 18 from patients suffering from diarrhea, were investigated for their enterohemolytic phenotypes and genotypes. Twenty-two strains were EHEC hemolysin (EHEC Hly) positive by probe hybridization and by PCR with sequences complementary to the EHEC hlyA gene of E. coli O157:H7, but only 20 of these were hemolytic on blood agar plates. The remaining 14 strains were EHEC Hly negative according to DNA-based methods and did not express the enterohemolytic phenotype. The enterohemolytic phenotype was observed in 16 of 18 (88%) strains from patients with HUS but only in 4 of 18 (22.2%) of the STEC O111:H- strains from patients with diarrhea. All STEC O111:H- strains carried large plasmids, as shown by plasmid analysis, but only plasmids of EHEC Hly probe-positive strains hybridized with the CVD419 probe. A BamHI fragment of approximately 12 kb was cloned from the large plasmid of the E. coli O111:H- strain 78/92 and shown to mediate hemolytic activity when transformed into the E. coli laboratory strain HB101. The EHEC O111 hlyA gene was sequenced completely and shown to have 99.4% sequence identity to the corresponding EHEC O157 hlyA gene of the E. coli O157:H7 strain EDL 933. Our results indicate that detection of EHEC Hly either by DNA-based methods or by investigation of the enterohemolytic phenotype on blood agar alone is insufficient for screening STEC O111 strains. However, the high incidence of EHEC Hly in isolates from patients with HUS and its rare occurrence in isolates from patients with diarrhea may indicate that STEC O111 strains have a distinct pathogenic potential for humans and that the presence of EHEC Hly increases the ability of an STEC O111 strain to cause extraintestinal complications in humans.
| S-EPMC229269 | biostudies-other
Project description:Many pathogens produce the ?-(1-6)-linked poly-N-acetylglucosamine (PNAG) surface polysaccharide that is being developed as a broadly protective antimicrobial vaccine. However, it is unknown whether systemically injected PNAG vaccines or antibodies would provide protective immunity against pathogens confined to the gastrointestinal tract such as Shiga toxin (Stx)-producing Escherichia coli (STEC), an important group of gastrointestinal (GI) pathogens for which effective immunotherapeutics are lacking. To ascertain whether systemic IgG antibody to PNAG impacts this infectious situation, a vaccine consisting of a synthetic nonamer of nonacetylated PNAG, 9GlcNH2, conjugated to the Shiga toxin 1b subunit (9GlcNH2-Stx1b) was produced. Rabbit antibodies raised to the conjugate vaccine were tested for bacterial killing and toxin neutralization in vitro and protection against infection in infant mice. Cell surface PNAG was detected on all 9 STEC isolates tested, representing 6 STEC serogroups, including E. coli O157:H7. Antibody to the 9GlcNH2-Stx1b conjugate neutralized Stx1 potently and Stx2 modestly. For O157:H7 and O104:H4 STEC strains, antibodies elicited by the 9GlcNH2-Stx1b conjugate possessed opsonic killing and bactericidal activity. Following intraperitoneal injection, antibodies to both PNAG and Stx were needed for infant mouse protection against O157 STEC. These antibodies also mediated protection against the Stx2-producing O104:H4 strain that was the cause of a recent outbreak in Germany, although sufficient doses of antibody to PNAG alone were protective against this strain in infant mice. Our observations suggest that vaccination against both PNAG and Stx, using a construct such as the 9GlcNH2-Stx1b conjugate vaccine, would be protective against a broad range of STEC serogroups. IMPORTANCE The presence of poly-N-acetylglucosamine (PNAG) on many pathogens presents an opportunity to target this one structure with a multispecies vaccine. Whether antibodies to PNAG can protect against pathogens confined to the gastrointestinal tract is not known. As Shiga toxin (Stx)-producing Escherichia coli (STEC) bacteria are serious causes of infection whose virulence is dependent on elaboration of Stx, we prepared a vaccine containing a synthetic nonamer of PNAG (9GlcNH2) conjugated to Shiga toxin 1b subunit (9GlcNH2-Stx1b) to evaluate bacterial killing, toxin neutralization, and protective efficacy in infant mice. All nine (100%) clinical strains of STEC from different serogroups expressed PNAG. Vaccine-induced antibody mediated in vitro killing of STEC and neutralization of both Stx1 and Stx2. Passive administration of antibody to the conjugate showed protection requiring immunity to both PNAG and Stx for O157 strains, although for an O104 strain, antibody to PNAG alone was protective. Immunity to PNAG may contribute to protection against STEC infections.
| S-EPMC3977355 | biostudies-literature
Project description:Enterohemorrhagic Escherichia coli (EHEC) strains are important human food-borne pathogens. EHEC strains elaborate potent Shiga toxins (Stx1, and/or Stx2) implicated in the development of hemorrhagic colitis (HC) or hemolytic-uremic syndrome (HUS). In this report, we evaluated the immunogenicity and protective efficacy of Stx1 subunit B (StxB1) administered by transcutaneous immunization (TCI). Three groups of Dutch Belted rabbits received patches containing StxB1, StxB1 in combination with Escherichia coli heat-labile enterotoxin (LT), or LT alone. An additional group of naïve rabbits served as controls. The protective efficacy following TCI with StxB1 was assessed by challenging rabbits with a virulent Stx1-producing strain, RDEC-H19A, capable of inducing HC and HUS in rabbits. Antibodies specific to StxB1 from serum and bile samples were determined by enzyme-linked immunosorbent assay and toxin neutralization test. Rabbits immunized with StxB1 demonstrated improved weight gain and reduced Stx-induced histopathology. Rabbits receiving StxB or StxB1/LT showed a significant increase in serum immunoglobulin G titers specific to StxB1 as well as toxin neutralization titers. These data demonstrated that the StxB delivered by TCI could induce significant systemic immune responses. Thus, Stx subunit B vaccine delivered by a patch for a high-risk population may be a practical approach to prevent (and/or reduce) Stx-induced pathology.
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