The intimin gene eae, located within the locus of enterocyte effacement pathogenicity island, distinguishes enteropathogenic Escherichia coli (EPEC) and some Shiga toxin-producing E. coli (STEC) strains from all other pathotypes of diarrheagenic E. coli. EPEC is a leading cause of infantile diarrhea in developing countries, and intimin-positive STEC isolates are typically associated with life-threatening diseases such as hemolyticuremic syndrome and hemorrhagic colitis. Here we describe the development of a PCR-restriction fragment length polymorphism (RFLP) assay that reliably differentiates all 11 known intimin types (␣1, ␣2, , ␥, , , , , , , and ) and three new intimin genes that show less than 95% nucleotide sequence identity with existing intimin types. We designated these new intimin genes Int-, Int-, and Int-. The PCR-RFLP assay was used to screen 213 eae-positive E. coli isolates derived from ovine, bovine, and human sources comprising 60 serotypes. Of these, 82 were STEC isolates, 89 were stx-negative (stx ؊ ) and ehxA-positive (ehxA ؉ ) isolates, and 42 were stx ؊ and ehxA-negative isolates. Int-, the most commonly identified eae subtype (82 of
Unlike Shiga toxin 2 (stx 2 ) genes, most nucleotide sequences of Shiga toxin 1 (stx 1 ) genes from Shiga toxin-producing Escherichia coli (STEC), Shigella dysenteriae, and several bacteriophages (H19B, 933J, and H30) are highly conserved. Consequently, there has been little incentive to investigate variants of stx 1 among STEC isolates derived from human or animal sources. However stx 1OX3 , originally identified in an OX3:H8 isolate from a healthy sheep in Germany, differs from other stx 1 subtypes by 43 nucleotides, resulting in changes to 12 amino acid residues, and has been renamed stx 1c . In this study we describe the development of a PCR-restriction fragment length polymorphism (RFLP) assay that distinguishes stx 1c from other stx 1 subtypes. The PCR-RFLP assay was used to study 378 stx 1 -containing STEC isolates. Of these, 207 were isolated from sheep, 104 from cattle, 45 from humans, 11 from meat, 5 from swine, 5 from unknown sources, and 1 from a cattle water trough. Three hundred fifty-five of the 378 isolates (93.9%) also possessed at least one other associated virulence gene (ehxA, eaeA, and/or stx 2 ); the combination stx 1 , stx 2 , and ehxA was the most common (175 of
IMPORTANCE Enterovirus 71 (EV71) causes a spectrum of neurological complications with significant morbidity and mortality. Further understanding of the characteristics of EV71-related neurological disease, factors related to outcome, and potential responsiveness to treatments is important in developing therapeutic guidelines. OBJECTIVE To further characterize EV71-related neurological disease and neurological outcome in children. DESIGN, SETTING, AND PARTICIPANTS Prospective 2-hospital (The Sydney Children's Hospitals Network) inpatient study of 61 children with enterovirus-related neurological disease during a 2013 outbreak of EV71 in Sydney, Australia. The dates of our analysis were January 1, to June 30, 2013. MAIN OUTCOMES AND MEASURES Clinical, neuroimaging, laboratory, and pathological characteristics, together with treatment administered and functional motor outcomes, were assessed. RESULTS Among 61 patients, there were 4 precipitous deaths (7%), despite resuscitation at presentation. Among 57 surviving patients, the age range was 0.3 to 5.2 years (median age, 1.5 years), and 36 (63%) were male. Fever (100% [57 of 57]), myoclonic jerks (86% [49 of 57]), ataxia (54% [29 of 54]), and vomiting (54% [29 of 54]) were common initial clinical manifestations. In 57 surviving patients, EV71 neurological disease included encephalomyelitis in 23 (40%), brainstem encephalitis in 20 (35%), encephalitis in 6 (11%), acute flaccid paralysis in 4 (7%), and autonomic dysregulation with pulmonary edema in 4 (7%). Enterovirus RNA was more commonly identified in feces (42 of 44 [95%]), rectal swabs (35 of 37 [95%]), and throat swabs (33 of 39 [85%]) rather than in cerebrospinal fluid (10 of 41 [24%]). Magnetic resonance imaging revealed characteristic increased T2-weighted signal in the dorsal pons and spinal cord. All 4 patients with pulmonary edema (severe disease) demonstrated dorsal brainstem restricted diffusion (odds ratio, 2; 95% CI, 1-4; P = .001). Brainstem or motor dysfunction had resolved in 44 of 57 (77%) at 2 months and in 51 of 57 (90%) at 12 months. Focal paresis was evident in 23 of 57 (40%) at presentation and was the most common persisting clinical and functional problem at 12 months (observed in 5 of 6 patients), with 1 patient also requiring invasive ventilation. Patients initially seen with acute flaccid paralysis or pulmonary edema had significantly greater frequencies of motor dysfunction at follow-up compared with patients initially seen with other syndromes (odds ratio, 15; 95% CI, 3-79; P < .001). CONCLUSIONS AND RELEVANCE Enterovirus 71 may cause serious neurological disease in young patients. The distinct clinicoradiological syndromes, predominantly within the spinal cord and brainstem, enable rapid recognition within evolving outbreaks. Long-term functional neurological morbidity is associated with paresis linked to involvement of gray matter in the brainstem or spinal cord.
A common mammalian defence mechanism employed to prevent systemic dissemination of invasive bacteria involves occlusion of local microvasculature and encapsulation of bacteria within fibrin networks. Acquisition of plasmin activity at the bacterial cell surface circumvents this defence mechanism allowing invasive disease initiation. To facilitate this process, S. pyogenes secrete streptokinase, a plasminogen activating protein.Streptokinase polymorphism exhibited by S. pyogenes isolates is well characterised. However, the functional differences displayed by these variants and the biological significance of this variation has not been elucidated. Phylogenetic analysis of ska sequences from 28 S. pyogenes isolates revealed two main sequence clusters (clusters 1 and 2). All strains secreted streptokinase as determined by western blotting and were capable of acquiring cell-surface plasmin activity after incubation in human plasma. Whereas culture supernatants from strains containing cluster 1 ska alleles also displayed soluble plasminogen activation activity, supernatants from strains containing cluster 2 ska alleles did not. Furthermore, plasminogen activation activity in culture supernatants from strains containing cluster 2 ska alleles could only be detected when plasminogen was prebound with fibrinogen. This study indicates that variant streptokinase proteins secreted by S. pyogenes isolates display differing plasminogen activation characteristics and may therefore play distinct roles in disease pathogenesis. AbstractA common mammalian defence mechanism employed to prevent systemic dissemination of invasive bacteria involves occlusion of local microvasculature and encapsulation of bacteria within fibrin networks. Acquisition of plasmin activity at the bacterial cell surface circumvents this defence mechanism allowing invasive disease initiation. To facilitate this process, S. pyogenes secrete streptokinase, a plasminogen activating protein. Streptokinase polymorphism exhibited by S. pyogenes isolates is well characterised. However, the functional differences displayed by these variants and the biological significance of this variation has not been elucidated. Phylogenetic analysis of ska sequences from 28 S. pyogenes isolates revealed two main sequence clusters (clusters 1 and 2). All strains secreted streptokinase as determined by western blotting and were capable of acquiring cell-surface plasmin activity after incubation in human plasma. Whereas culture supernatants from strains containing cluster 1 ska alleles also displayed soluble plasminogen activation activity, supernatants from strains containing cluster 2 ska alleles did not. Furthermore, plasminogen activation activity in culture supernatants from strains containing cluster 2 ska alleles could only be detected when plasminogen was pre-bound with fibrinogen. This study indicates that variant streptokinase proteins secreted by S. pyogenes isolates display differing plasminogen activation characteristics and may therefore play distinct roles in...
Shiga toxin 2 (Stx2) has been reported as the main Shiga toxin associated with human disease. In addition, the Stx2 toxin type can have a profound impact on the degree of tissue damage in animal models. We have characterized the stx 2 subtype of 168 Shiga toxin-producing Escherichia coli (STEC) isolates of which 146 were derived from ovine sources (principally feces and meat) and 22 were isolated from humans.
Two months after the December 2004 tsunami in Tamil Nadu, India, we surveyed adults aged 18 years or older in a severely affected coastal village using structured interviews and the Harvard Trauma Questionnaire. The prevalence of posttraumatic stress disorder was 12.7% (95% confidence interval [CI]=9.4%, 17.1%), and odds of posttraumatic stress disorder were higher among individuals with no household incomes, women, and those injured during the tsunami. In addition to promoting feelings of safety, interventions aimed toward populations affected by the December 2004 tsunami need to focus on income-generating activities. Also, there is a need to target initiatives toward women and those individuals injured during the tsunami, given that these groups are more likely to experience posttraumatic stress disorder.
In 2016, the Transplantation Society of Australia and New Zealand, with the support of the Australian Government Organ and Tissue authority, commissioned a literature review on the topic of infectious disease transmission from deceased donors to recipients of solid organ transplants. The purpose of this review was to synthesize evidence on transmission risks, diagnostic test characteristics, and recipient management to inform best-practice clinical guidelines. The final review, presented as a special supplement in Transplantation Direct, collates case reports of transmission events and other peer-reviewed literature, and summarizes current (as of June 2017) international guidelines on donor screening and recipient management. Of particular interest at the time of writing was how to maximize utilization of donors at increased risk for transmission of human immunodeficiency virus, hepatitis C virus, and hepatitis B virus, given the recent developments, including the availability of direct-acting antivirals for hepatitis C virus and improvements in donor screening technologies. The review also covers emerging risks associated with recent epidemics (eg, Zika virus) and the risk of transmission of nonendemic pathogens related to donor travel history or country of origin. Lastly, the implications for recipient consent of expanded utilization of donors at increased risk of blood-borne viral disease transmission are considered.
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