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PubMed2002

Streptococcus pyogenes prtFII, but not sfbI, sfbII or fbp54, is represented more frequently among invasive-disease isolates of tropical Australia.

Streptococcus pyogenes (group A streptococcus) strains may express several distinct fibronectin-binding proteins (FBPs) which are considered as major streptococcal adhesins. Of the FBPs, SfbI was shown in vitro to promote internalization of the bacterium into host cells and has been implicated in persistence. In the tropical Northern Territory, where group 4 streptococcal infection is common, multiple genotypes of the organism were found among isolates from invasive disease cases and no dominant strains were observed. To determine whether any FBPs is associated with invasive disease propensity of S. pyogenes, we have screened streptococcal isolates from bacteraemic and necrotizing fasciitis patients and isolates from uncomplicated infections for genetic endowment of 4 FBPs. No difference was observed in the distribution of sfbII, fbp54 and sfbI between the blood isolates and isolates from uncomplicated infection. We conclude that the presence of sfbI does not appear to promote invasive diseases, despite its association with persistence. We also show a higher proportion of group A streptococcus strains isolated from invasive disease cases possess prtFII when compared to strains isolated from non-invasive disease cases. We suggest that S. pyogenes may recruit different FBPs for different purposes.

Adhesins, Bacterial↗

PubMed2004

Function of the fibronectin-binding serum opacity factor of Streptococcus pyogenes in adherence to epithelial cells.

The serum opacity factor (SOF) of Streptococcus pyogenes is a serotyping tool and pathogenesis factor. Using SOF-coated latex beads in cell adherence assays and antiserum directed against SOF in S. pyogenes-HEp-2 cell adherence inhibition experiments, we demonstrate SOF involvement in the fibronectin-mediated adherence of S. pyogenes to epithelial cells. SOF exclusively targets the 30-kDa N-terminal region of fibronectin. The interaction revealed association and dissociation constants 1 order of magnitude lower than those of other S. pyogenes fibronectin-binding proteins.

Binding Sites↗

PubMed1975

In vitro sensitivity of hemophilus influenzae and streptococcus pyogenes to co-trimoxazole.

The invitro testing of Hemophilus influenzae and Streptococcus pyogenes for co-trimoxazole sensitivity requires certain "defined" media that have to be free of inhibitory substances. The use of Columbia agar base with Fildes extract for H. influenzae or of blood agar for S. pyogenes may produce "false-resistant" strains. The addition of thymidine phosphorylases in the form of gentlylysed horse blood (2 to 10%) does not remove all inhibitors in those tests, especially where "undefined" agar bases are used, and results in scanty growth of H. influenzae; the addition of more than 2% results in dark plates, making reading of sensitivities difficult. Fildes agar for testing H. influenzae may be made with enriched sheep or horse blood if the proper "defined" agar base is used. The use of Wellcotest or DST (Oxoid) agar is recommended with Fildes extract for H. influenzae or with blood for S. pyogenes for in vitro testing for co-trimoxazole sensitivity. The addition of thymidine phosphorylase in the form of 2% lysed horse blood does not interfere with reading. However, it results in scanty growth of H. influenzae. Proper inoculation of plates is important. The growth on the plates should be light, dense, but not confluent. Heavy growth may render some strains "false-resistant" even when defined media are used. Our results indicate that many of the previously reported resistant strains of H. influenzae and S. pyogenes may have been "false-resistant" because of the use of "undefined" media. We believe that, in view of our results, respiratory infections may be treated with co-trimoxazole until bacteriologic studies prove that this treatment is contraindicated, since H. influenzae and S. pyogenes are usually found sensitive in vitro under proper conditions.

Animals↗

PubMed2006

Resistance to erythromycin and rising penicillin MIC in Streptococcus pyogenes in India.

There has been worldwide resurgence in the incidence of Streptococcus pyogenes infection and its sequelae. S. pyogenes remains uniformly susceptible to penicillin, and it is speculated that its minimum inhibitory concentration (MIC) has not changed during the past 70 years. The purpose of the present study was to determine the occurrence and pattern of resistance to penicillin and erythromycin amongst clinical isolates of S. pyogenes. A total of 34 clinical strains of S. pyogenes were identified by standard procedures. Antimicrobial susceptibility was analyzed by the Kirby-Bauer method of disk diffusion, and the E-test method was used to determine the MIC to penicillin and erythromycin. All the strains were sensitive to penicillin, clindamycin and vancomycin on disk diffusion. Ten (29.4%) strains were resistant to erythromycin. The pattern of macrolide resistance observed was M type. By the E-test method, 7 (20.6%) strains were penicillin nonsusceptible and 6 (17.6%) were erythromycin resistant. We concluded that surveillance of its susceptibility pattern is crucial to monitoring the development of antibiotic resistance in S. pyogenes.

Disk Diffusion Antimicrobial Tests↗

PubMed2002

[Incidence and distribution of Streptococcus pyogenes type M in patients treated at the Dr. Fran Mihaljević Infectious Disease Clinic in Zagreb from 1990 to 1996].

AIM: The aim of this study was to estimate the changes in the appearance and distribution of M types of Streptococcus pyogenes in different cultures from 78 patients treated during the 1990-1996 period at the Dr. Fran Mihaljević University Hospital for Infectious Diseases in Zagreb. MATERIALS AND METHODS: Isolates were characterized by the T-agglutination pattern and M type and/or opacity factor type using the standards recommended by two World Health Organization Collaborating Centers for Reference and Research on streptococci from Minneapolis and Prague. RESULTS: In this study, 19% (15/79) of isolates were recovered from normally sterile sites, 26.6% (21/79) came from skin and 54.4% (43/79) from throat swabs. In one patient isolates from the skin and blood culture were analyzed. Of all, 92.4% (73/79) of the isolates were typed by T-agglutination pattern and 73.5% (58/79) by M protein and/or OF typing. The results of M typing showed 14 M types: M1, M3, M4, M5, M6, M11, M12, M28, M57, M58, M60, M75, M76 and M78. The most commonly isolated types were M1 and M3 (13.8%, 8/58 each), followed by M28 found in 12.1% (7/58), and M6 and M12 in 10.3% (6/58) each. These five M types accounted for 60.3% (35/58) of all isolates. Analysis to changes in the distribution of M1 and M3 types during the 1990-1991 and 1992-1993 periods revealed a significantly greater proportion of M1 and M3 isolates in the former (Fisher's two-tailed exact test, p = 0.018). A significantly greater proportion of M1 and M3 isolates was also recorded in the 1990-1991, than in 1994-1996 period. (Fisher's two-tailed exact test, P = 0.021). It was investigated whether Streptococcus pyogenes M1 and M3 types were associated with toxic and invasive infection. There were 28.2% (22/78) of patients with toxic and invasive infection: 31.9% (7/22) of them with the diagnosis of scarlet fever, whereas 68.1% (15/22) of the strains were obtained from normally sterile sites. There were 45.5% (10/22) of M1 and M3 types from patients with toxic and invasive infections. Types M6, M28 and M76 were found in an equal proportion of 9.1% (2/22), and M4, M12 and M 60 of 4.5% (1/22) each. In three strains, M type could not be identified (T8/25 SOR+, T25 SOR+ and T11 SOR+). M1 and M3 types were isolated from 10.3% (6/56) of patients with other streptococcal infections. A significantly greater proportion of M1 and M3 types was recorded in patients with toxic and invasive infections than in those with other streptococcal infections (Fisher's two-tailed exact test, p = 0.004). A multivariate logistic regression model was used to assess whether the increased proportion of streptococcal M types 1 and 3 was associated with the 1990-1991 period, or with the infection characteristics. CONCLUSIONS: The changes in the distribution of M types 1 and 3 were found to be significantly associated only with toxic and invasive infections (odds ratio 4.35, p = 0.025). Odds ratio suggests that patients with toxic and invasive infections had a 4.35--fold increased risk of infections caused by types M1 and M3 found in patients with other streptococcal infections. The increased proportion of M types 1 and 3 during the 1990-1991 period was more significantly associated with the characteristics of infection than with the study period.

Antigens, Bacterial↗

PubMed2004

Clindamycin-resistant Streptococcus pyogenes: report of a case.

A sentinel isolate of clindamycin-resistant Streptococcus pyogenes from a case of mixed aerobic-anaerobic necrotizing fasciitis prompted our clinical laboratory to change its protocol and subsequently perform routine susceptibility testing on all S. pyogenes isolated from blood and soft tissue specimens. Emerging clindamycin resistance may have serious implications in the treatment of severe S. pyogenes infections.

Adult↗

PubMedDate not supplied

Interactions of fibronectin with streptococci: the role of fibronectin as a receptor for Streptococcus pyogenes.

Current evidence suggests that lipoteichoic acid (LTA) on the surface of Streptococcus pyogenes is centrally involved in the adherence of these bacteria to the oral mucosa. The major receptor on the surface of buccal mucosal cells for S. pyogenes is fibronectin. Fibronectin is a complex glycoprotein found in blood, extracellular matrices, and saliva. Many species of streptococci bind to fibronectin, although the characteristics of these interactions are different. Furthermore, whereas LTA is an efficient inhibitor of the binding of fibronectin to group A streptococci, it has little ability to inhibit the binding of fibronectin to Streptococcus pneumoniae or Staphylococcus aureus. Studies conducted with fibronectin show that different bacteria bind to different sites. The ability of various bacteria to interact with different domains on the fibronectin molecule may play an important role in bacterial adherence and tissue tropism.

Animals↗

PubMed2005

Persistence of Streptococcus pyogenes in stationary-phase cultures.

In addition to causing fulminant disease, Streptococcus pyogenes may be asymptomatically carried between recurrent episodes of pharyngitis. To better understand streptococcal carriage, we characterized in vitro long-term stationary-phase survival (>4 weeks) of S. pyogenes. When grown in sugar-limited Todd-Hewitt broth, S. pyogenes cells remained culturable for more than 1 year. Both Todd-Hewitt supplemented with excess glucose and chemically defined medium allowed survival for less than 1 week. After 4 weeks of survival in sugar-limited Todd-Hewitt broth, at least 10(3) CFU per ml remained. When stained with fluorescent live-dead viability stain, there were a number of cells with intact membranes that were nonculturable. Under conditions that did not support persistence, these cells disappeared 2 weeks after loss of culturability. In persistent cultures, these may be cells that are dying during cell turnover. After more than 4 weeks in stationary phase, the culturable cells formed two alternative colony phenotypes: atypical large colonies and microcolonies. Protein expression in two independently isolated microcolony strains, from 14-week cultures, was examined by use of two-dimensional electrophoresis. The proteomes of these two strains exhibited extensive changes compared to the parental strain. While some of these changes were common to the two strains, many of the changes were unique to a single strain. Some of the common changes were in metabolic pathways, suggesting a possible alternate metabolism for the persisters. Overall, these data suggest that under certain in vitro conditions, S. pyogenes cells can persist for greater than 1 year as a dynamic population.

Bacteriological Techniques↗

PubMed1994

Serotypes of Streptococcus pyogenes isolated from healthy school children in Kangwon-do.

Seventy-seven Streptococcus pyogenes strains isolated of children of three elementary schools located in Kangwon-do in spring, 1992 were serotyped with M, opacity factor (OF) and T typing antisera. In the M/OF typing results, M-78 (46.8%) and M-28 (22.1%) were most frequently encountered, while M-4 (6.5%), M-12 (5.2%), M-3 (1.3%), M-5 (1.3%) and M-6 (1.3%) were rarely observed. Twelve strains (15.6%) were not typable with M or OF typing system. In the T typing results, T-11 (35.1%) and T-28 (27.3%) were most common. We were able to identify 77.9% of S. pyogenes strains by T typing, 94.8% with T typing and OF typing. With the addition of M typing, 97.4% were typable. Through the serotypings, we could know the basic distribution of serotypes of S. pyogenes of healthy children which could be comparable to those of rheumatic fever, poststreptococcal glomerulonephritis and other severe streptococcal disease.

Adolescent↗

PubMed2006

Roles of the alternative complement pathway and C1q during innate immunity to Streptococcus pyogenes.

Complement is important for innate immunity to the common bacterial pathogen Streptococcus pyogenes, but the relative importance of the alternative and classical pathways has not been investigated. Using mice and human serum deficient in either C1q, the first component of the classical pathway, or factor B, an important component of the alternative pathway, we have investigated the role of both pathways for innate immunity to S. pyogenes. C3b deposition on four different strains of S. pyogenes was mainly dependent on factor B. As a consequence opsonophagocytosis of S. pyogenes was reduced in serum from factor B-deficient mice, and these mice were very susceptible to S. pyogenes infection. In contrast, C3b deposition was not dependent on C1q for two of the strains investigated, H372 and H305, yet opsonophagocytosis of all four S. pyogenes strains was impaired in serum deficient in C1q. Furthermore, infection in C1q-deficient mice with strain H372 resulted in a rapidly progressive disease associated with large numbers of bacteria in target organs. These results demonstrate the important role of the alternative pathway and C1q for innate immunity to S. pyogenes and suggest that C1q-mediated innate immunity to at least some strains of S. pyogenes may involve mechanisms that are independent of C3b on the bacteria.

Animals↗

PubMed2003

SIC, a secreted protein of Streptococcus pyogenes that inactivates antibacterial peptides.

Some isolates of the significant human pathogen Streptococcus pyogenes, including virulent strains of the M1 serotype, secrete protein SIC. This molecule, secreted in large quantities, interferes with complement function. As a result of natural selection, SIC shows a high degree of variation. Here we provide a plausible explanation for this variation and the fact that strains of the M1 serotype are the most frequent cause of severe invasive S. pyogenes infections. Thus, protein SIC was found to inactivate human neutrophil alpha-defensin and LL-37, two major antibacterial peptides involved in bacterial clearance. This inactivation protected S. pyogenes against the antibacterial effect of the peptides. Moreover, SIC isolated from S. pyogenes of the M1 serotype was more powerful in this respect than SIC variants from strains of M serotypes 12 and 55, serotypes rarely connected with invasive infections.

Antimicrobial Cationic Peptides↗

PubMed2006

Sigma X induces competence gene expression in Streptococcus pyogenes.

Although not thought to become competent for DNA uptake, the bacterium Streptococcus pyogenes appears to encode within its genome the DNA uptake and recombination machinery required for competence. The promoters of these genes contain a conserved sequence, CIN-box, which is recognized by the S. pyogenes alternative RNA polymerase sigma factor X. Using microarray technology, we found that sigma X induced the expression of competence genes in S. pyogenes. Real-time RT-PCR was performed to confirm that the expression of these transcripts was induced 2-265-fold by sigma X. Of the eight CIN-box loci induced, femB, the ortholog a virulence factor in Staphylococcus aureus, was shown to be transcribed in vitro by RNA polymerase containing sigma X, indicating that sigma X directly activates expression of this CIN-box gene. Sigma X-dependent induction of genes encoding competence machinery in S. pyogenes raises the possibility that some strains of this human pathogen can develop competence for genetic transformation.

Bacillus subtilis↗

PubMed2003

Streptococcus pyogenes expressing M and M-like surface proteins are phagocytosed but survive inside human neutrophils.

Strains of the Gram-positive human pathogen Streptococcus pyogenes (group A streptococcus) that express surface-associated M or M-like proteins survive and grow in non-immune fresh human blood. This is generally accepted to be caused by an antiphagocytic property of these proteins. However, in most previous studies, an inhibition of the internalization of the bacteria into host cells has not been studied or not directly demonstrated. Therefore, in the present paper, we used flow cytometry, fluorescence microscopy and electron microscopy to study phagocytosis by human neutrophils of wild-type S. pyogenes and strains deficient in expression of M protein and/or the M-like protein H. The results demonstrate that all strains of S. pyogenes tested, including the wild-type AP1 strain, induce actin polymerization and are efficiently phagocytosed by human neutrophils. In addition, using classical bactericidal assays, we show that the wild-type AP1 strain can survive inside neutrophils, whereas mutant strains are rapidly killed. We conclude that the ability of virulent S. pyogenes to survive and multiply in whole blood is most likely not possible to explain only by an antiphagocytic effect of bacterial surface components. Instead, our data suggest that bacterial evasion of host defences occurs intracellularly and that survival inside human neutrophils may contribute to the pathogenesis of S. pyogenes and the recurrence of S. pyogenes infections.

Actins↗

PubMed1997

Cell wall anchoring of the Streptococcus pyogenes M6 protein in various lactic acid bacteria.

The M6 protein from Streptococcus pyogenes is the best-characterized member of a family of cell envelope-associated proteins. Based on the observation that the C-terminal sorting signals of these proteins can drive cell wall anchoring of heterologous unanchored proteins, we have cloned and expressed the emm6 structural gene for the M6 protein in various lactic acid bacteria (LAB). The emm6 gene was successfully expressed from lactococcal promoters in several Lactococcus lactis strains, an animal-colonizing Lactobacillus fermentum strain, Lactobacillus sake, and Streptococcus salivarius subsp. thermophilus. The M6 protein was efficiently anchored to the cell wall in all strains tested. In lactobacilli, essentially all detectable M6 protein was cell wall associated. These results suggest the feasibility of using the C-terminal anchor moiety of M6 for protein surface display in LAB.

Antigens, Bacterial↗

PubMed1999

Macrolide resistance phenotypes and mechanisms of resistance in Streptococcus pyogenes in La Rioja, Spain.

One hundred and thirty seven consecutive clinical Streptococcus pyogenes isolates were evaluated for macrolide-lincosamide-streptogramin resistance (MLS). Forty of these isolates were resistant to erythromycin (29.2%), 36 of them showed the new M resistance phenotype (erythromycin resistant and clindamycin susceptible) and four isolates had the MLS(B) resistance phenotype (erythromycin and clindamycin resistant). In all 36 isolates with the M resistance phenotype, the mef gene was identified by polymerase chain reaction (PCR). In two of the four S. pyogenes isolates with the MLS(B) phenotype, both ermB and ermTR genes were found; negative results were obtained with the other two isolates which might possess a new mechanism of high level resistance against erythromycin not previously described. In summary, a high rate of erythromycin resistance was found in S. pyogenes isolates and the active efflux pump mediated by the mef gene was the mechanism most frequently involved.

Anti-Bacterial Agents↗

PubMed1999

Incidence of erythromycin resistance in Streptococcus pyogenes: a 10-year study.

We studied the evolution of susceptibility of Streptococcus pyogenes isolated in our hospital from 1987 to 1996. Susceptibility to penicillin, ampicillin, cefotaxime, cefuroxime, imipenem, erythromycin, clindamycin, tetracycline, vancomycin, ciprofloxacin, rifampin, and chloramphenicol was determined by the National Committee for Clinical Laboratory Standards broth microdilution method. Differentiation of phenotypes of erythromycin-resistant strains was performed using the double-disc method. All isolates remained very susceptible in vitro to penicillin and all of the other beta-lactam agents tested. Between 1987 and 1995 the incidence of erythromycin resistant strains remained below 5%; the difference in the resistance rate between 1995 (2.6%) and 1996 (17.1%) was statistically significant. The macrolide resistance M phenotype was the most frequent. The isolation rates of tetracycline-resistant strains increased from 2.2% in 1987 to 11.2% in 1988. The marked increase in the incidence of erythromycin resistance observed in our area warrants periodic surveillance of antibiotic susceptibility of S. pyogenes isolates and emphasizes the need to control outpatient antibiotics. The preponderance of the M phenotype may have implications in the choice of antibiotic.

Anti-Bacterial Agents↗

PubMed2005

Global epithelial cell transcriptional responses reveal Streptococcus pyogenes Fas regulator activity association with bacterial aggressiveness.

The bacterial human pathogen Streptococcus pyogenes (group A streptococci, GAS) is able to adhere to, internalize into and cross-talk on multiple levels with its host cells. To gain insight into the Fas function in pathogenesis we used Affymetrix human genome DNA-arrays to measure temporal and global transcriptional responses of HEp-2 cells infected with M49 S. pyogenes wild-type bacteria and DeltafasX, an isogenic S. pyogenes two-component-signal-transduction system mutant. A modified stringent statistical analysis method identified a total of 86 HEp-2 cell genes as differentially transcribed upon infection over the investigated time course. Increased expression of genes encoding proteins involved in GAS host cell adherence and internalization (fibronectin, integrin-alpha5) was found as a common response. In contrast to earlier reports investigating other GAS serotype strains, Ras superfamily and RhoA pathways are exploited by M49 GAS, suggesting serotype specific interactions with the host cell cytoskeleton. Despite transcriptional induction, secreted IL-8 levels of deltafasX mutant infected cells were below those of non-infected cells, indicating an absence of Fas expression could be important for GAS tissue colonization and long-term intracellular persistence. Oppositely, activity of the S. pyogenes Fas-system apparently promotes high adherence and internalization rates, massive cytokine gene transcription and cytokine release, host cell apoptosis via a caspase-2 activation pathway, and cytotoxicity. Thus, the S. pyogenes Fas two-component signal transduction system could be involved in local tissue destruction and general bacterial aggressiveness towards host cells.

Apoptosis↗

PubMed1998

Streptococcus pyogenes hospital-acquired infection within a dermatological ward.

Seventeen strains of Streptococcus pyogenes were isolated from 17 patients in the Dermatological Ward of Gunma University Hospital in Japan between June 1994 and March 1995. Of these 17 strains, 14 were isolated from the pus of skin infections, two from blood, and one from ascitic fluid. The strains showed the same minimum inhibitory concentrations; 4 mg/L of minomycin, 4 mg/L of ofloxacin and 16 mg/L of fosfomycin. T-antigen typing of the strains indicated they were T11 type. The restriction endonuclease digestion patterns of chromosomal DNA from the 17 strains were all identical. The vinyl sheet covering the bed on which the patients were treated was found to be contaminated with S. pyogenes. This strain showed identical characteristics to the strains derived from the patients. These results suggest that S. pyogenes was transmitted to patients in the Dermatological Ward from the surface of the vinyl sheet covering the bed.

Bedding and Linens↗