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Group A beta-hemolytic Streptococcus pyomyositis continues to be an uncommon disease. We present a case of a 7-year-old boy with an M protein type 1, streptococcal pyrogenic exotoxin A and B, Streptococcus pyogenes pyomyositis and streptococcal toxic shock syndrome.
Pathogenic bacteria often produce proteinases that are believed to be involved in virulence. Moreover, several host defence systems depend on proteolysis, demonstrating that proteolysis and its regulation play an important role during bacterial infections. Here, we discuss how proteolytical events are regulated at the surface of Streptococcus pyogenes during infection with this important human pathogen. Streptococcus pyogenes produces proteinases, and host proteinases are produced and released as a result of the infection. Streptococcus pyogenes also recruits host proteinase inhibitors to its surface, suggesting that proteolysis is tightly regulated at the bacterial surface. We propose that the initial phase of a S. pyogenes infection is characterized by inhibition of proteolysis and complement activity at the bacterial surface. This is achieved mainly through binding of host proteinase inhibitors and complement regulatory proteins to bacterial surface proteins. In a later phase of the infection, massive proteolytic activity will release bacterial surface proteins and degrade human tissues, thus facilitating bacterial spread. These proteolytic events are regulated both temporally and spatially, and should influence virulence and the outcome of S. pyogenes infections.
Streptococcus pyogenes is capable of causing a variety of human diseases ranging from superficial or deep tissue infections to non-infectious post-streptococcal infection sequelae. In this paper, we report the use of a Tn917-lacZ transposon to isolate random lacZ transcription fusions in the S. pyogenes chromosome. Libraries of random Tn917-lacZ mutants were generated in a representative opacity factor positive strain CS101 (M49) and an opacity factor negative strain 1881 (M1). Several different mutant phenotypes were isolated. These included: temperature-regulated promoters, growth phase/cell density-regulated promoters and a human plasma-inducible promoter. Expression of the temperature-regulated fusions was 5-10-fold higher when grown at 30 degrees C compared to growth at 37 degrees C. The growth phase-regulated fusions were induced 30-fold at late exponential phase and were repressed by a diffusible S. pyogenes factor(s). Expression of the human plasma-inducible fusion was induced 10-15-fold by human plasma or sera, 4-fold by rabbit sera and was repressed by horse and mouse sera. In addition, hemolysin negative and capsule over expression mutants were isolated. These results demonstrate the utility of Tn917-lacZ mutagenesis for the identification of S. pyogenes promoters.
Streptococcus pyogenes is an important pathogen that causes pharyngitis, sepsis, and rheumatic fever. Cell-associated streptococcal C5a peptidase (ScpA) protects S. pyogenes from phagocytosis and has been suggested to interrupt host defenses by enzymatically cleaving complement C5a, a major factor in the accumulation of neutrophils at sites of infection. How S. pyogenes recognizes and binds to C5a, however, is unclear. We detected a C5a-binding protein in 8 M urea extracts of S. pyogenes by ligand blotting using biotinylated C5a. Searching of genome databases showed that the C5a-binding protein is identical to the streptococcal plasmin receptor (Plr), also known as streptococcal surface dehydrogenase (SDH) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). In the present study we identified a novel function of this multifunctional protein. Western blotting and immunofluorescence microscopy with anti-Plr/SDH/GAPDH showed that Plr/SDH/GAPDH is located on the bacterial surface and released into the culture supernatant. Next, we examined whether the streptococcal Plr/SDH/GAPDH inhibits the biological effects of C5a on human neutrophils. We found that soluble Plr/SDH/GAPDH inhibits C5a-activated chemotaxis and H2O2 production. Furthermore, our results suggested that soluble Plr/SDH/GAPDH captures C5a, inhibiting its chemotactic function. Also, cell-associated Plr/SDH/GAPDH and ScpA were both necessary for the cleavage of C5a on the bacterial surface. Together, these results indicate that the multifunctional protein Plr/SDH/GAPDH has additional functions that help S. pyogenes escape detection by the host immune system.
Streptococcus pyogenes causes septic sore throat in millions of Americans each year and may be transmitted from food handlers to food contact surfaces, foods, and consumers. This study examined the individual survival of six S. pyogenes strains on food contact surfaces (plastic and ceramic plates, plastic cups, and stainless steel utensils) held at 21 degrees C for 2 h and on tomatoes stored aerobically at 21 degrees C for 2 h and at 5 degrees C for 24 h. Survival of a cocktail of the six S. pyogenes strains was also evaluated on vacuum-packaged ready-to-eat meats and cheeses held at 21 degrees C for 8 h and at 5 degrees C for 24 h. Populations generally did not change on tomatoes, cheeses, or beef bologna; however, there were small (0.1 to 0.7 log CFU) but statistically significant decreases (P < 0.05) in average S. pyogenes populations on turkey luncheon meat and beef summer sausage stored for 8 h at 21degrees C and on beef summer sausage stored for 24 h at 5 degrees C. On food contact surfaces, average populations either decreased slightly (P > or = 0.05) or remained constant, with the exception of three strains that significantly decreased in number on ceramic plates (P < 0.05; average decreases, 0.3 log CFU). Results of this study suggest the importance of preventing the contamination of foods and food contact surfaces with S. pyogenes by infected workers.
Streptococcus pyogenes, nontypable with available M antisera, T type 12, and reactive in the serum opacity test, produced various lesions in 10 newborn infants during a 2-month period. All infants except one were discharged from the nursery before overt disease manifestations. Colonization studies of newborn infants showed a streptococcal carrier rate of 19% (27 of 140). Only 1 of 154 staff members yielded the same streptococcus from the throat, but it could not be implicated as the source for the outbreak. Cohorting of infants and chlorhexidine gluconate hand washing by staff members helped in terminating this cluster epidemic.
The pathogens Streptococcus pyogenes and Moraxella catarrhalis colonize overlapping regions of the human nasopharynx. We have found that M. catarrhalis can dramatically increase S. pyogenes adherence to human epithelial cells and that species-specific coaggregation of these bacteria correlates with this enhanced adherence.
A stabilized L-form of Streptococcus pyogenes continues to synthesize glycerol teichoic acid. This polymer was obtained from S. pyogenes and its L-form, treated in identical fashion, and compared. Highly purified glycerol teichoic acid from only the L-form was found to be devoid of d-alanine and to have a shorter chain length. Otherwise, the glycerol teichoic acid from these two organisms was found to be a 1,3-phosphodiester-linked glycerophosphate polymer substituted with d-glucose. Evidence is presented that most, if not all, of the glycerol teichoic acid in this streptococcus lies between the wall and membrane. A possible need for the continued synthesis of a minute amount of glycerol teichoic acid by this L-form for survival is discussed in terms of the known function of teichoic acids in bacteria.
Macrolides are currently used to treat Streptococcus pyogenes infections where allergy or resistance prevents the use of penicillin. However, growing macrolide resistance is now seen worldwide, with rates of 5%-40% being reported. In this context it is therefore important to have other therapeutic options. The aim of this study was to ascertain the potential role of moxifloxacin, a third-generation fluoroquinolone, in the treatment of infections caused by group A S. pyogenes. The antimicrobial susceptibilities of S. pyogenes isolated from 197 adult patients with pharyngotonsillitis were analyzed by the E-test. Twelve percent of the isolates were resistant to macrolides, and 5% showed diminished susceptibility toward penicillin; none of the strains were resistant to cefotaxime or to moxifloxacin (90% minimum inhibitory concentration, 0.25 microg/mL). Therefore, moxifloxacin may be a therapeutic option in the management of S. pyogenes infections when penicillin cannot be used or when macrolide resistance may be a local issue. Clinical studies of moxifloxacin in pharyngotonsillitis are warranted.
Erythromycin (ERY) resistance in Streptococcus pyogenes has recently emerged as a problem of growing concern all through the world. We are presenting the comparison of results of the continuous surveillance of erythromycin resistance in S. pyogenes performed since 1989 in the Hospital de Pediatría J.P. Garrahan of Buenos Aires City, with independently observed rates in other five centers of Buenos Aires and seven centers of six other Argentinian cities, obtained between 1999 and 2001. A significant increase of erythromycin resistance was observed among S. pyogenes isolated in the Hospital Garrahan (6.6% in 1998-1999 to 9.9% in 2000). Similar trends were also detected in other centers of other Argentinian cities when recent data were compared to results of a multicenter study performed in 1995. However, lower rates of resistance were recorded in Mendoza, Cipolletti and Neuquén in comparison with data of 1995, 1998 and 1998 respectively. The reason of such decreasing resistance rates deserves to be investigated. The average of ERY-resistance rates obtained in the surveyed centers was 6.7% (range 0.5-14.1%). Control of antimicrobial use should be performed to warrant the future effectiveness of macrolide antibiotics regarding the positive association between use and resistance. These results also suggest that susceptibility tests for macrolides should be performed whenever S. pyogenes is isolated in Argentina.
Streptococcus pyogenes is the most frequent causative agent of acute pharyngotonsillitis (AT). The first events in the etiopathogenesis of an AT infection caused by these bacterial pathogens are their penetration through the mucus film covering the oropharyngeal mucosa, and their attachment to the surface epithelium. Adherence of S. pyogenes to tonsillar epithelial cells is a precondition for bacterial colonisation, for triggering off cell activation, internalising of bacteria into the epithelial cells and cytokine release from the epithelial cells with subsequent induction of an inflammatory reaction in underlying tissues. Scanning and transmission electron microscopic studies revealed that the surface epithelium of the human palatine tonsils consisted of a weakly keratinized, stratified squamous epithelium built up of pentangular cells where the apical cell surface formed an irregular pattern of microridges. The distance between two adjacent microridges was roughly one-third of the diameter of a S. pyogenes bacterium. By using gold-labelled antiserum to S. pyogenes, we showed that the target region for these pathogens on the epithelial cells during an on-going AT infection was located on the crests of the microridges where bacterial pili made adhesin-receptor contact with the tonsillar surface epithelium.
During an 18-month period 1,002 strains of Streptococcus pyogenes, consecutively isolated in the laboratory from a wide variety of lesions, were typed by the precipitin and slide-agglutination tests. The relative frequency of serotypes in different diseases was examined and a close association between type 4 in scarlet fever and type 3.13 in impetigo noted. An apparent lack of any relationship between particular serotypes and streptococcal sore throat was evident. The difficulty of distinguishing the more virulent types of Str. pyogenes and correlating a type-specific disease relationship is discussed.
Previous studies using mouse models of Streptococcus pyogenes necrotizing fasciitis demonstrated that clindamycin had greater efficacy than penicillin. Frequently both agents are used concurrently in the treatment of severe S. pyogenes infections. This study investigated interactions between penicillin and clindamycin. E-test and broth microdilution assays suggested additivity or indifference, while timed-killing assays demonstrated concentration-dependent variable effects. Timed-kill studies utilizing clinical concentrations suggest that there is no antagonism with the combination of drugs but that the combination does not have a bactericidal advantage over either penicillin or clindamycin alone.
Twenty-four community isolates of Streptococcus pyogenes resistant to ciprofloxacin and susceptible to levofloxacin, gatifloxacin, and moxifloxacin were studied. Sequence determination of the quinolone resistance-determining regions in the gyrA and parC genes revealed a T/G mutation in parC leading to a Ser79Ala substitution in ParC. All isolates were of the emm type 6, and 18 and 2 of them were indistinguishable or closely related, respectively, on the basis of pulsed-field gel electrophoresis.
Strains of Streptococcus pyogenes from an outbreak in an oncology ward (13) and routine isolates from sporadic cases (6) were examined blind by pyrolysis mass spectrometry (Py-MS), extending previous work on epidemiological typing. This outbreak appeared more complex than one reported previously, but Py-MS and conventional typing results were in complete agreement. The results confirm the potential of Py-MS as a rapid method for identification at strain level in studies of cross infection.
The pathogenic Gram-positive bacterium Streptococcus pyogenes (group A streptococcus) binds to fibronectin via protein F. In this study, we have investigated the binding properties of protein F to various multimeric tissue forms of fibronectin that appear on cell surfaces and in the extracellular matrix. We show that binding of S. pyogenes through protein F is more efficient to an in vitro-derived polymerized form of fibronectin (superfibronectin) than to soluble fibronectin immobilized in a solid phase. In addition, Chinese hamster ovary cells overexpressing the alpha5beta1 integrin produced an increased amount of a fibronectin matrix and consequently bound a higher number of S. pyogenes cells. Inhibition and direct binding assays using purified proteins demonstrated that binding to a fibronectin matrix involved both domains of protein F (UR and RD2) that have previously been implicated in interactions with fibronectin. Using intact S. pyogenes bacteria in which various domains of protein F were expressed as hybrids with the surface-exposed region of an unrelated protein, we revealed that, in contrast to the predominantly UR-mediated binding to soluble fibronectin, the maximal binding to the fibronectin matrix required RD2 in addition to UR. Since in some infections S. pyogenes may initially encounter a matrix form of fibronectin, these results suggest that UR and RD2 may be important for the initiation of streptococcal infectious processes.
The pathogenic gram-positive bacterium Streptococcus pyogenes (group A streptococcus) causes numerous diseases of cutaneous tissue, each of which is initiated after the interaction of the bacterium with the cells of the epidermis. In this study, we show that different surface proteins of S. pyogenes play important roles in determining the cell-specific tropism of the bacterium in skin. Using streptococcal strains with defined mutations in the genes which encode surface proteins in combination with primary cultures of human skin and an in situ adherence assay which uses histological sections of human skin, we show that the M protein of S. pyogenes mediates the binding of the bacterium to keratinocytes, while a second streptococcal surface protein, protein F, directs the adherence of the organism to Langerhans' cells. Characterization of binding revealed that adherence was inhibited by purified streptococcal proteins and pretreatment of both host cells with the protease trypsin. Adherence was only slightly affected by the state of keratinocyte differentiation in vitro, but was considerably modulated in response to environmental conditions known to regulate expression of M protein and protein F, suggesting that the interaction between these bacterial cell-surface structures/adhesins and keratinocytes and Langerhans' cells may play an important role in streptococcal skin disease.
We have tested the ability of Streptococcus pyogenes to produce streptococcal pyrogenic exotoxin A (SPEA) and superantigenic activity in the presence of sub-inhibitory concentrations of ampicillin and clindamycin. After 6 h of culture, SPEA production by S. pyogenes was higher in broths containing ampicillin (715.7 +/- 296.4 pg/10(6) cfu) than in broths containing clindamycin (167.1 +/- 31.9 pg/10(6) cfu), a difference that was not significant (P = 0.25). Promitogenic activity of bacterial supernatants was also greater in ampicillin-treated cultures (467.5 +/- 17.2 ccpm/10(6) cfu) than in clindamycin-treated cultures (169.2 +/- 8.9 ccpm/10(6) cfu), a difference that was highly significant (P = 0.0001). The data support the use of clindamycin in the treatment of streptococcal toxic shock-like syndrome, in order to inhibit superantigen synthesis.