Where are the receptors for Streptococcus pyogenes located on the tonsillar surface epithelium?

Impact of Streptococcus pyogenes infection in susceptibility to psoriasis: A systematic review and meta-analysis

BACKGROUND

Psoriasis is one of the most common chronic systemic diseases, mainly appearing as lesions on the skin and joints, and is associated with a high mortality due to a lack of standard treatment. The exact mechanism of this disease is not fully understood, but the inflammatory response and dysregulation of the immune system are the most important molecular processes that trigger this disease. The skin microflora is one of the main factors involved in inducing, maturing, and dysregulating the immune system, which may underly the development of psoriasis.

AIM

To determine the impact of Streptococcus pyogenes (S. pyogenes) infection and susceptibility to psoriasis using available case-control studies.

METHODS

In this study, we conducted a comprehensive literature search using PubMed, Scopus, Web of science, and Google scholar databases to obtain all available relevant studies on the association between S. pyogenes and psoriasis. We pooled the data using Comprehensive Meta-analysis software to investigate the role of S. pyogenes infection in the development of psoriasis. The probable connection between S. pyogenes and susceptibility to psoriasis was assessed using the odds ratio (OR) with corresponding 95% confidence intervals (CIs).

RESULTS

Data from 781 cases were evaluated in this study. Our results showed that the rate of infection with S. pyogenes in psoriatic patients and healthy individuals was 33.4% (95%CI: 27.8-39.6) and 16.2% (95%CI: 9.7-25.9), respectively. S. pyogenes infection significantly increased the risk of psoriasis (OR: 6.58; 95%CI: 3.64-11.87; P = 0.001).

CONCLUSION

S. pyogenes infection can significantly increase the risk of psoriasis. Thus, infection with S. pyogenes is a risk factor for the initiation and development of psoriatic events.

Frequency of streptococcal upper respiratory tract infections and HLA-Cw*06 allele in 70 patients with guttate psoriasis from northern Poland

Introduction

The association of guttate psoriasis with a streptococcal throat infection and HLA-Cw*06 allele is well established in different populations. Nevertheless, only few studies on this form of disease have been performed in the Polish population.

Aim

To analyze the frequencies of streptococcal-induced guttate psoriasis and HLA-Cw*06 allele in 70 patients with guttate psoriasis originating from northern Poland.

Material and methods

Seventy patients with guttate psoriasis and 24 healthy volunteers were enrolled into the study. Both groups were sex- and age-matched. The evidence of streptococcal infection was based on the positive throat swabs and/or elevated ASO titers. The modified method, including PCR-SSP and PCR-RFLP, was applied to HLA-Cw*06 genotyping.

Results

HLA-Cw*06 allele was confirmed in 49 (70%) out of 70 patients, which is significantly higher than in the control population (30%) (p = 0.001). Evidence for streptococcal infection was found in 34 (48.5%) subjects with psoriasis. Twenty-seven of them (79%) carried HLA-Cw*06 allele. In 36 individuals in whom no evidence of streptococcal infection was found, 14 (39%) did not carry HLA-Cw*06 allele.

Conclusions

Our data confirm that HLA-Cw*06 is a major, but not imperative, genetic determinant for guttate psoriasis.

Virulence factors of Actinobacillus pleuropneumoniae involved in colonization, persistence and induction of lesions in its porcine host

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia. The virulence factors of this microorganism involved in colonization and the induction of lung lesions have been thoroughly studied and some have been well characterized. A. pleuropneumoniae binds preferentially to cells of the lower respiratory tract in a process involving different adhesins and probably biofilm formation. Apx toxins and lipopolysaccharides exert pathogenic effects on several host cells, resulting in typical lung lesions. Lysis of host cells is essential for the bacterium to obtain nutrients from the environment and A. pleuropneumoniae has developed several uptake mechanisms for these nutrients. In addition to persistence in lung lesions, colonization of the upper respiratory tract – and of the tonsils in particular – may also be important for long-term persistent asymptomatic infection. Information on virulence factors involved in tonsillar and nasal cavity colonization and persistence is scarce, but it can be speculated that similar features as demonstrated for the lung may play a role.

Adherence and internalization of Streptococcus gordonii by epithelial cells involves beta1 integrin recognition by SspA and SspB (antigen I/II family) polypeptides

Streptococcus gordonii is a commensal bacterium that colonizes the hard and soft tissues present in the human mouth and nasopharynx. The cell wall-anchored polypeptides SspA and SspB expressed by S. gordonii mediate a wide range of interactions with host proteins and other bacteria. In this article we have determined the role of SspA and SspB proteins, which are members of the streptococcal antigen I/II (AgI/II) adhesin family, in S. gordonii adherence and internalization by epithelial cells. Wild-type S. gordonii DL1 expressing AgI/II polypeptides attached to and was internalized by HEp-2 cells, whereas an isogenic AgI/II- mutant was reduced in adherence and was not internalized. Association of S. gordonii DL1 with HEp-2 cells triggered protein tyrosine phosphorylation but no significant actin rearrangement. By contrast, Streptococcus pyogenes A40 showed 50-fold higher levels of internalization and this was associated with actin polymerization and interleukin-8 upregulation. Adherence and internalization of S. gordonii by HEp-2 cells involved beta1 integrin recognition but was not fibronectin-dependent. Recombinant SspA and SspB polypeptides bound to purified human alpha5beta1 integrin through sequences present within the NAV (N-terminal) region of AgI/II polypeptide. AgI/II polypeptides blocked interactions of S. gordonii and S. pyogenes with HEp-2 cells, and S. gordonii DL1 cells expressing AgI/II proteins inhibited adherence and internalization of S. pyogenes by HEp-2 cells. Conversely, S. gordonii AgI/II- mutant cells did not inhibit internalization of S. pyogenes. The results suggest that AgI/II proteins not only promote integrin-mediated internalization of oral commensal streptococci by host cells, but also potentially influence susceptibility of host tissues to more pathogenic bacteria.

Noticeable differences in bacterial defence on tonsillar surfaces between bacteria-induced and virus-induced acute tonsillitis

OBJECTIVE

Oral and pharyngeal cavities harbor a commensal bacterial flora which is kept in check by several innate and acquired agents. In this study, we focused on the proportions in which some antibacterial moderators (lysozyme, lactoferrin, IgG and S-IgA) coat the tonsillar surface bacteria in healthy individuals, in patients with acute tonsillitis (AT) culture-positive for Streptococcus pyogenes, and in patients with infectious mononucleosis (IM) caused by Epstein-Barr virus (EBV).

METHODS

Bacterial samples were collected for aerobic culturing and immunocytochemical evaluation from the tonsillar surfaces of eight healthy individuals (four males, four females; age range 16-22 years), eight patients with current AT (two males, six females; age range 16-29 years) and seven patients with IM (four males, three females; age range 15-21 years). The immunocytochemical assay was based on gold-labeled antiserum to human lysozyme, lactoferrin, IgG and S-IgA followed by gold particle tracing in the transmission electron microscope.

RESULTS

During AT, a significant increase in lysozyme coating (P<0.05) and lactoferrin coating (P<0.0005) of the bacteria was noted, whereas the S-IgA coating was significantly reduced (P<0.0005). During IM infection, a significant increase in lactoferrin coating was noted (P<0.0005) whereas immunoglobulin coating was significantly reduced (IgG P<0.025; S-IgA P<0.0005) compared with healthy controls. During IM, all antibacterial moderators evaluated were significantly reduced compared with the situation during AT.

CONCLUSIONS

Noticeable changes in the local innate and acquired bacterial defence system were observed during tonsillar infections, particularly during IM.