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Cytolytic Vaginosis, Aerobic Vaginitis, and Desquamative Inflammatory Vaginitis
Published in William J. Ledger, Steven S. Witkin, Vulvovaginal Infections, 2017
William J. Ledger, Steven S. Witkin
Both S. pyogenes and S. aureus have a multitude of mechanisms to prevent their detection and/or elimination by the host’s immune system. The major immune defense against S. pyogenes is recognition, phagocytosis and killing of the microorganism by polymorphonuclear leukocytes. One of the S. pyogenes proteins, known as M protein, has potent antiphagocytosis properties. It binds to factor H and C4b-binding protein, components of the complement system, and prevents complement deposition on the streptococcal surface and subsequent opsonization. Similarly, fibronectin binds to M protein, thereby masking the bacterial surface from recognition. Streptococcal-derived C5a peptidase, endoglycosidase, and Mac1-like protein also limit complement activation as well as antibody binding and leukocyte recruitment. Streptolysin O, a streptococcal virulence factor, also blocks phagocytic functions.18
Streptococcus
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
GAS expresses a number of surface proteins and virulence factors that facilitate its attachment and entry into human host cells, and escape from human immune surveillance. For example, GAS produces M protein, Cpa, Eno, Epf, and firbronectin-binding proteins for extracellular matrix and serum protein binding via microbial surface components recognizing adhesive matrix molecules (MSCRAMMS); secretes EndoS, Mac, C5a peptidase, capsule protein, and Sic for degradation/inhibition of host immunoglobulin and complement factor; utilizes plasminogen/plasmin binding and streptokinase Ska activity for dysregulation of coagulation; generates SLS, SLO, streptococcal pyrogenic exotoxins A and C (SpeA and SpeC, which are superantigens responsible for scarlet fever and STSS), and Nga for cytotoxic and cytolytic activity toward various host cell types, including neutrophils, platelets, and subcellular organelles [15,16].
Group B Streptococcus colonisation and their antimicrobial susceptibility among pregnant women attending antenatal clinics in tertiary care hospitals in the Western Province of Sri Lanka
Published in Journal of Obstetrics and Gynaecology, 2021
G. N. Dilrukshi, J. Kottahachchi, D. M. B. T. Dissanayake, R. P. Pathiraja, J. Karunasingha, M. K. A. Sampath, U. A. Vidanage, S. S. N. Fernando
The drug of choice for GBS infection is penicillin; ampicillin, erythromycin and clindamycin are frequently used as alternative drugs. Previous studies which were conducted both locally and internationally have demonstrated that some GBS isolates showed intermediate or decreased sensitivity, in vitro, to penicillin and ampicillin (Dissanayake et al. 2015; Goudarzi et al. 2015). This decreasing sensitivity to penicillin needs to be monitored due to possible development of resistance in the near future (Silbert et al. 2016). It is estimated that 0.7–4% of patients develop allergic reactions to penicillin (Spong et al. 2012). In clinical practice, broth culture in selective medium and subsequent subculture are the gold standard methods for identification of GBS colonisation (Verani et al. 2010). However, novel rapid methods such as polymerase chain reaction (PCR) are used in some countries (Wernecke et al. 2009; Alfa et al. 2010). A recent study has demonstrated that the culture method does not give positive results for all GBS. PCR targeting genes of Streptococcus agalactiae are 16S rRNA, cfb (CAMP factor), scpB (S.agalactiae C5a peptidase) and atr. Out of them, cfb gene is the most important gene that encodes the S. agalactiae CAMP factor which presents in all GBS universally (Clarke et al. 2016).
Systematic review of the clinical development of group B streptococcus serotype-specific capsular polysaccharide-based vaccines
Published in Expert Review of Vaccines, 2018
Sonwabile Dzanibe, Shabir A. Madhi
Although this review focused on CPS-based GBS vaccines, also under clinical development are protein only vaccines which too are now in phase I studies among pregnant women [69]. This vaccine includes two proteins, Alp-C and Rib-A which have been shown to be associated with reduced risk for invasive disease in infants in natural sero-immunity studies. The universality of the presence and expression of these proteins in GBS strains globally, however, remains to be defined. Other proteins such as Sip, BibA, C5a peptidase, and pilus island proteins have been shown to be capable of inducing serotype-independent protection against GBS disease in murine models [70–73]. Natural immunity against pilus proteins during pregnancy have also been shown to be associated with infant invasive disease, albeit there being conflicting evidence and no sero-protective level has been established [59,74]. Nonetheless, the potential of including these proteins either as a conjugate or mixed with other CPS-protein conjugate to enhance the potential protection of a GBS vaccine warrants further consideration.
Group B streptococcal carriage, antimicrobial susceptibility, and virulence related genes among pregnant women in Alexandria, Egypt
Published in Alexandria Journal of Medicine, 2018
Salama Mohamed Sadaka, Hala Abdelsalam Aly, Marwa Ahmed Meheissen, Yasser Ibrahim Orief, Basma Mohamed Arafa
DNA extraction from bacteria was performed by the method described by Schmitz et al.26The supernatant (three uL) was used as a template in the PCR reaction. Four separate PCR reactions were done. Each PCR reaction consisted of 12.5 μL MyTaq Red Mix, 2× (Bioline, UK), 25 pmol of primers, and PCR grade water to a final volume 25 μl. The sets of primers (Invitrogen by Life Technologies, Thermo Fisher Scientific Inc., USA) for the detection of genes encoding immunoglobulin A-binding β-antigen (bac), α-antigen (bca), C5a peptidase (scpB), and rib are listed in Table 1.