Virulence factors of Streptococcus pyogenes strains from women in peri-labor with invasive infections.

E Golińska,M Dorycka,A Samet,M Strus,A Piórkowska,P B Heczko,D Mikołajczyk,A Machul,G Więcek,M Van Der Linden

doi:10.1007/s10096-016-2593-0

E Golińska, M Dorycka + Show 8 more

Open Access

https://doi.org/10.1007/s10096-016-2593-0

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Abstract

Invasive group A streptococcal (GAS) infections constitute an important epidemiological problem. Many cases occur in women during the postnatal period. The objective of this study was to evaluate the presence of the genes responsible for production of iron-chelating protein (perR) and superantigens (speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, smeZ, and ssa) in S. pyogenes strains isolated from invasive infections in women after delivery. Furthermore, this study sought to verify whether S. pyogenes strains show special phenotypic and genotypic (sla, spy1325) characteristics that may play a decisive role in adherence to the genital tract epithelium. Moreover, the emm-types and antibiotic susceptibility were determined. We tested 30 invasive S. pyogenes strains isolated from postpartum invasive infection and 37 GAS control strains isolated from the genital tracts of asymptomatic multiparous women. The majority of the tested strains were shown to express two types of emm genes (1 and 28), though emm −12, −28, −75 and −89 were uniquely expressed in the group of strains isolated from invasive infections. A significantly higher prevalence of perR in the strains from puerperal fever was shown. Significant differences were also found between the two groups with respect to the incidence of the genes related to adherence; GAS strains originating from women with sepsis/puerperal fever showed presence of these genes less frequently than those of the control group. Although differences in frequencies of the gene coding for various superantigens were noted between the compared groups of GAS strains, they were not significant.

Highlights

Group A streptococci (GAS) have been recognized as one of the leading infectious agents in human puerperal fever
There were no significant differences between these two groups of the strains in frequency of emm types distribution
While it is conceivable that tissue site preferences for infection in the throat or skin might be explained by the expression and/or regulation of tissue-specific colonization factors such as adhesins, the exact mechanisms responsible for tissue tropism in the genital tract are yet to be elucidated [4]

Summary

Introduction

Group A streptococci (GAS) have been recognized as one of the leading infectious agents in human puerperal fever. GAS have been implicated in several more localized infections affecting the throat, skin, ear, sinuses, or vagina. Invasive infections such as streptococcal toxic shock syndrome and sepsis began to receive attention from epidemiologists only quite recently, when the United States, Norway, Sweden, and Denmark reported higher incidence rates, outbreaks, and even epidemics [1]. Systemic S. pyogenes infections commonly result in high mortality. Invasive S. pyogenes strains, which cause deep soft-tissue infections and fasciitis as well as streptococcal toxic shock syndrome (STSS) and sepsis, produce highly specific toxins with special pro-inflammatory properties. Streptococcal pyrogenic toxins (SPE) possess superantigen properties and bridge antigen-presenting cells with immune system effector cells, leading to their polyclonal activation

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