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M proteins of group C streptococci isolated from patients with acute pharyngitis.

ABSTRACT: We studied 15 strains of group C (Streptococcus equi subsp. equisimilis) [corrected] isolated from the throats of college students with acute pharyngitis and 5 strains isolated from patients with noninfectious problems. Nineteen of the 20 strains resisted phagocytic killing during incubation in normal human blood, suggesting that they might express M proteins. Genomic DNA from all 20 strains hybridized with a probe corresponding to the carboxyterminal one-third of the group A M-protein gene emm24, a region that is highly conserved among M proteins of group A and group G streptococci. The DNA sequences of the N-terminal (variable) regions of the M-protein-encoding genes from two disease-associated group C isolates and one control isolate were determined. The predicted amino acid sequences of the two pharyngitis strains were identical and were 88% homologous to the amino acid sequence of a group G M-protein gene. The predicted terminal amino acid sequence of the control strain does not correspond to any such sequences in the GenBank database. All three strains studied possess the conserved region domain common to class I group A M-protein types epidemiologically associated with rheumatic fever. These studies demonstrate the presence of M proteins in strains of S. equi subsp. equisimilis [corrected] isolated in cases of endemically occurring acute pharyngitis. Certain of these proteins are similar to those of group G streptococci, while others may represent new M types. The similarity in structure and function between M proteins of nonrheumatogenic serogroups and those of rheumatogenic group A streptococci suggests that factors other than or in addition to M protein per se are likely involved in the pathogenesis of rheumatic fever.

SUBMITTER: Bisno AL

PROVIDER: S-EPMC229307 | biostudies-other | 1996 Oct

REPOSITORIES: biostudies-other

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M proteins of group C streptococci isolated from patients with acute pharyngitis.

Bisno A L AL Collins C M CM Turner J C JC

Journal of clinical microbiology 19961001 10

We studied 15 strains of group C (Streptococcus equi subsp. equisimilis) [corrected] isolated from the throats of college students with acute pharyngitis and 5 strains isolated from patients with noninfectious problems. Nineteen of the 20 strains resisted phagocytic killing during incubation in normal human blood, suggesting that they might express M proteins. Genomic DNA from all 20 strains hybridized with a probe corresponding to the carboxyterminal one-third of the group A M-protein gene emm2 ...[more]

PMID: 8880511

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Project description:BackgroundA few lineages of Group A streptococci (GAS) have been associated with a reemergence of severe invasive streptococcal disease in developed countries. However, the majority of the comparisons between invasive and non-invasive GAS isolates have been performed for collections of reduced genetic diversity or relied on limited typing information to distinguish clones. We characterized by several typing methods and compared a collection of 160 isolates recovered from normally sterile sites with 320 isolates associated with pharyngitis and recovered in the same time period in Portugal.ResultsAlthough most of the isolates belonged to clones that were equally prevalent in invasive infections and pharyngitis, we identified markers of invasiveness, namely the emm types 1 and 64, and the presence of the speA and speJ genes. In contrast, emm4, emm75, and the ssa and speL/M genes were significantly associated with pharyngitis. There was a strong agreement between the emm type, the superantigen (SAg) genes and the clusters defined by pulsed-field gel electrophoresis (PFGE) profiling. Therefore, combinations of particular emm types and SAg genes frequently co-occurred in the same PFGE cluster, but there was no synergistic or antagonistic interaction between them in determining invasiveness. Only macrolide-susceptible PFGE clones were significantly associated with invasive infections or pharyngitis, while the clones of resistant isolates sharing all other molecular properties analyzed were equally prevalent in the two groups of isolates.ConclusionsThis study confirmed the importance of the widely disseminated emm1-T1-ST28 clone in invasive infections but also identified other clones linked to either invasive infections (emm64-ST164) or pharyngitis (emm4-T4-ST39), which may be more limited in their temporal and geographical spread. Clonal properties like some emm types or SAg genes were associated with disease presentation, highlighting the importance of bacterial genetic factors to the outcome of GAS infections, although other, yet unidentified factors may also play an important role.

Project description:ObjectivePeriodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is the most common periodic fever syndrome in children; by definition, episodes occur every 2 to 8 weeks. However, in a subset of our patients, we noticed a higher frequency of attacks, of less than 2 weeks, which we refer to as extreme PFAPA (ePFAPA). This group consisted of patients who were extreme upon presentation of PFAPA, and those who became extreme after initiation of abortive corticosteroid treatment. We aimed to characterize demographic and clinical features of ePFAPA, including the two groups, and to compare them to patients with non-extreme PFAPA (nPFAPA).Study designThe medical records of 365 patients with PFAPA who attended Schneider Children's Medical Center of Israel from March 2014 to April 2021 were reviewed. Patients with concomitant familial Mediterranean fever were excluded. Characteristics of the ePFAPA (including subgroups) and nPFAPA groups were compared using Wilcoxon rank sum, Pearson's chi-squared, and Fisher's exact tests.ResultsForty-seven patients (12.9%) were identified as having ePFAPA. Among patients with ePFAPA, compared to patients with nPFAPA, the median (interquartile range) age at disease onset was earlier: 1.5 years (0.7-2.5) vs. 2.5 years (1.5-4.0), P < 0.001; and diagnosis was younger: 2.6 years (2.0-3.6) vs. 4.5 years (3.0-6.2), P < 0.001. A higher proportion of patients with ePFAPA than nPFAPA were treated with colchicine prophylaxis (53% vs. 19%, P < 0.001), but symptoms and signs during flares did not differ significantly between these groups. Demographic and clinical characteristics were similar between patients with ePFAPA from presentation of PFAPA (22, 47% of those with ePFAPA) and ePFAPA from after corticosteroid treatment.ConclusionAbout half the patients categorized with ePFAPA syndrome already had extreme features upon presentation. Patients with ePFAPA compared to nPFAPA presented and were diagnosed at an earlier age.

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M proteins of group C streptococci isolated from patients with acute pharyngitis.

Publications

M proteins of group C streptococci isolated from patients with acute pharyngitis.

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