M-protein gene-type distribution and hyaluronic acid capsule in group AStreptococcusclinical isolates in Chile: association ofemmgene markers withcsrRalleles

Abstract

Streptococcus pyogenes causes a variety of infections because of virulence factors such as capsular hyaluronic acid and M protein. The aim of this study was to determine emm types and capsule phenotype in 110 isolates of S. pyogenes from patients with invasive (sterile sites) and non-invasive (mainly pharyngitis) infections in Chile, and the relationship between both virulence factors. The most abundant types found were emm12, emm1, emm4 and emm28 and their distribution was similar to that seen in Latin America and developed countries, but very different from that in Asia and Pacific Island countries. Ten of 16 emm types identified in pharyngeal isolates were found in sterile-site isolates, and three of nine emm types of sterile-site isolates occurred in pharyngeal isolates; three emm subtypes were novel. The amount of hyaluronic acid was significantly higher in sterile-site isolates but did not differ substantially among emm types. Only three isolates were markedly capsulate and two of them had mutations in the csrR gene that codes for a repressor of capsule synthesis genes. We found a non-random association between emm types and csrR gene alleles suggesting that horizontal gene transfer is not freely occurring in the population.

Severe Acute Otitis Media Caused by Mucoid<i> Streptococcus Pyogenes</i> in a Previously Healthy Adult

“…However, mucoid S. pyogenes has occasionally been reported to cause invasive disease in other countries (Tamayo et al 2010;Wozniak et al 2012). The mucoid phenotype is due to abundant production of the hyaluronic acid capsular polysaccharide, a key virulence factor associated with severe S. pyogenes infection (Gryllos et al 2008).…”

“…There have been reports of bacterial meningitis as a complication of otitis media or mastoiditis due to S. pyogenes (Cohen-Kerem and Lavon 2002;Laupland and Bosch 2006). Generally, S. pyogenes forms non-mucoid colonies with a matt surface and causes β-hemolysis on sheep's blood agar medium (Chang et al 2011;Wozniak et al 2012). In Japan, mucoid S. pyogenes has rarely been reported because of the quite low detection rate of mucoid type isolates, and the epidemiological features of mucoid S. pyogenes infection are not fully understood.…”

A Novel Live Vector Group A StreptococcalemmType 9 Vaccine Delivered Intranasally Protects Mice against Challenge Infection withemmType 9 Group A Streptococci

“…For the preparation of the infective inoculum, an erythromycin-resistant emm type 9 GAS clinical isolate (strain no. 75) that had been previously reported (15) was grown in Todd-Hewitt broth overnight at 37°C. Mouth washes were plated in Trypticase soy agar supplemented with 5% sheep's blood and erythromycin (2 g/ml).…”

“…The N-terminal domain of M proteins elicits antibodies with high bactericidal (protective) activity (14) and is considered a viable candidate vaccine antigen. We recently conducted a study of the molecular epidemiology of GAS infections in Chile and determined the emm type distribution (15). This knowledge was applied to select the most common emm types to include them in the design of this new vaccine.…”

Genome-wide analysis of Streptococcus pyogenes associated with pharyngitis and skin infections. (c2015)

“…Large-scale studies have successfully associated several emm types with geographical and socioeconomical areas of the world (Henningham et al, 2013;Smeesters et al, 2008;Steer et al, 2009). In industrialized societies for example, the most prevalent S. pyogenes isolates are of emm type 1, 3, 12, and 28, making up around 40% of GAS associated diseases in such areas (Shea et al, 2011;Wozniak et al, 2012), while these same emm types are isolated less frequently from the indigenous populations of less developed regions including Africa, the Pacific Islands, and the Indian subcontinent (Dhanda et al, 2011;Kumar et al, 2012). In addition to the socioeconomic factors, temporal and geographical variability, play an important role in the isolation of prevalent emm types in a certain region in a given year (Shea et al, 2011).…”