The molecular determination of emm genotypes in non-group a beta-hemolytic streptococci isolated from clinical samples (original) (raw)
Related papers
Molecular Characterization of Group B Streptococcus Serotypes By Multiplex Polymerase Chain Reaction
Medical Express, 2017
OBJECTIVE: Group B Streptococcus (GBS) serotypes (Ia, Ib and II to IX) are classified based on variations in their capsular polysaccharide; their prevalence differs between different geographic areas. We examined the prevalence of all GBS serotypes in rectal and vaginal swab samples obtained from 363 pregnant women followed at a Brazilian referral center (Hospital da Mulher Professor Doutor José Aristodemo Pinotti); bacterial susceptibility to antibiotics was further determined. METHOD: Prevalence of positive GBS was evaluated by latex agglutination and by multiplex PCR analysis; bacterial susceptibility to antibiotics, such as clindamycin, erythromycin, levofloxacin, linezolid, penicillin and tetracycline was determined by the disk diffusion method. RESULTS: (a) standard GBS culture and the multiplex PCR analysis tested positive for 83 swabs, collected from 72 women (prevalence of GBS colonization: 72/363; 20%); the most prevalent Serotype was Ia (n=43/83; 52%), followed by serotype V (n=14/83; 17%); according to anatomical origin, serotype Ia accounted for 27/59 (46%) and 16/24 (67%) of the vaginal and rectal samples, respectively; PCR also identified serotypes Ib, II, III and VI. Serotype VI is rarely described and had not been previously reported in Brazil or in Latin America. (b) The latex agglutination test only identified 44 positive samples, all of which were serotyped: 34 of these samples (77%) had serotypes matching those identified by multiplex PCR. (c) Only one sample (serotype Ia) showed resistance to erythromycin and clindamycin. CONCLUSION: Regional studies on GBS serotypes prevalence are essential to guide immunoprophylactic interventions (vaccines) and the implementation of adequate antibiotic prophylaxis or treatment. In this study, the incidence of the serotype VI, a new and rare serotype of GBS was described for the first time in a Brazilian population.
emm type diversity of β-haemolytic streptococci recovered in Chennai, India
Journal of Medical Microbiology, 2008
Correspondence emm type diversity of b-haemolytic streptococci recovered in Chennai, India Beta-haemolytic streptococci (BHS) are widely spread human pathogens, and include group A, G and C streptococci. Group A streptococci (GAS) are mostly found in the throat and on the skin and commonly cause pharyngitis and impetigo, although they are most notorious for causing a broad spectrum of severe invasive disease (Cunningham, 2000). Recent studies have indicated that group C and G streptococci (GCS, GGS) also carry Streptococcus pyogenes superantigen genes and have been reported with increasing frequency from a variety of severe infections (Davies et al., 2005; Kalia & Bessen, 2003). The M type specific typing scheme for GAS, based upon the hypervariable region of the emm gene, also applies to GCS and GGS (Bisno et al., 1996; Collins et al., 1992). The objective of this study was to investigate the diversity of BHS in Chennai, south India, by emm gene sequencing.
Serotype Identification of Group B Streptococci by PCR and Sequencing
Streptococcus agalactiae) is the most common cause of neonatal and obstetric sepsis and is an increasingly important cause of septicemia in elderly individuals and immunocompromised patients. Ongoing surveillance to monitor GBS serotype distribution will be needed to guide the development and use of GBS conjugate vaccines. We designed sequencing primers based on the previously published sequences of the capsular polysaccharide (cps) gene clusters to further define partial cps gene clusters for eight of the nine GBS serotypes (serotypes Ia to VII). Subsequently, we designed and evaluated primers to identify serotypes Ia, Ib, III, IV, V, and VI directly by PCR and all eight serotypes (serotypes Ia to VII) by sequence heterogeneity. A total of 206 clinical GBS isolates were used to compare our molecular serotype (MS) identification method with conventional serotyping (CS). All clinical isolates were assigned an MS, whereas 188 of 206 (91.3%) were assigned a serotype by use of antisera. A small number of isolates (serosubtypes III-3 and III-4) showed different serotype specificities between PCR and sequencing, but the PCR results correlated with those obtained by CS. The overall agreement between the MS identification method and CS for isolates for which results of both tests were available was 100% (188 of 188 isolates). The MS identification method is a specific and practical alternative to conventional GBS serotyping and will facilitate epidemiological studies.
Background: Group B streptococcus (GBS) is the major cause of serious life threatening infections in neonates, pregnant women, and other adults with underlying diseases. Capsular polysaccharide typing is a significant way for epidemiological studies of GBS, the pathogenesis, and other studies associated with GBS infections including surveillance programs and vaccine development in future. Molecular serotyping (MS) methods offer more accurate and reliable typing of bacteria. The aim of current study was to differentiate genotypes of clinical GBS isolates based on PCR assay to acquire information about the distribution of GBS types in Hamadan, Iran. Materials and Methods: A total of 62 clinical GBS strains including vaginal swabs, urine cultures, and blood culture isolates were examined for genotyping using multiplex PCR assay. Results: Among the 62 GBS isolates examined, all capsular types, except VI, VII, and VIII, were found. Type III was the predominant type with 35 isolates (56.5%), followed by Type V with 11 isolates (17.7%), Type II with 7 isolates (11.3%), Type Ia with 5 isolates (8.1%), and Types Ib and IV with similar prevalence of 2 isolates (3.2%) for each type. Conclusion: The results of the current study demonstrated that Type III is the predominant type in Hamadan, followed by Types V, II, Ia, Ib, and IV, respectively. Using MS method leads to accurate, sensitive, specific, and fast typing of GBS isolates. The advantages of MS method allow it to analyze various populations and to examine invasive and colonizing isolates in extensive epidemiological studies and surveillance activities. In fact, MS will facilitate the proper formulation of candidate GBS vaccines.
Infection Epidemiology and Microbiology
Backgrounds: Group B Streptococcus (GBS) is an important opportunistic bacterial pathogen that could cause serious infections, especially in neonates, adults, and the elderly. In GBS isolates, a macrolide resistance phenotype that confers constitutive resistance to macrolidelincosamide-streptogramin B antibiotics (cMLSB phenotype) has become a global concern. On the other hand, little is known about the genetic relatedness and diversity of GBS isolates isolated from various patients in Iran. Hence, this study aimed to determine the genetic relatedness and molecular typing of cMLSB-GBS isolates using enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) technique. Materials & Methods: A total of 100 GBS isolates were collected from patients with urinary tract infections (UTIs). Among them, 52 erythromycin-resistant GBS isolates were selected, and double-disc diffusion (D-zone) technique was applied to determine the MLSB phenotype among the isolates based on CLSI criteria. Then the genetic relatedness of MLSB-GBS isolates was assessed using ERIC-PCR fingerprinting method. Findings: Among 52 erythromycin-resistant GBS isolates, 38 isolates were identified with cMLSB phenotype, nine isolates with M phenotype, and five isolates with iMLSB phenotype. The analysis of ERIC-PCR patterns revealed eight different ERIC types that were divided into seven clusters (A-G) and one single type. Also, four isolates were non-typeable. ERIC type A/ serotype Ib was the most prevalent clone among the isolates. Conclusion: The current study findings showed a high level of diversity and multiclonal spread of the cMLSB phenotype in Isfahan. ERIC type A/ serotype Ib is the predominant clone circulating among erythromycin-resistant GBS strains.
Journal of Clinical Microbiology, 2011
We report the results from the first international multicenter external quality assessment (EQA) studies for molecular and serological typing of group B streptococcus (GBS) strains as part of DEVANI (Design of a Vaccine against Neonatal Infections), a pan-European program. A questionnaire-based surveillance was undertaken among eight laboratories participating in DEVANI and six laboratories not participating in DEVANI from 13 countries in order to assess their current microbiological procedures for GBS screening, diagnosis, and typing. GBS strains from three EQA distributions were characterized using molecular and serological methods based on GBS capsular polysaccharide typing. Participants were asked to test the first distribution using their current serotyping and genotyping methods. The Strep-B-Latex agglutination method was the most widely used method, with a typeability value of >90%. A multiplex PCR assay for GBS capsular gene typing was also used by 2 of 14 centers, which achieved a typeability value of 93%; this assay detected only 9 of 10 GBS capsular polysaccharide genes. From the second and third EQA studies, standardized protocols were prepared for serological and molecular typing of GBS strains based on the Strep-B-Latex agglutination method and a novel multiplex PCR assay that detected all 10 GBS capsular types (Ia to IX). These standardized protocols are being used by many European laboratories, and as the use of these methods increases, it is imperative to continuously improve and assess laboratory performance and offer training to any laboratories that have technical difficulties.
Journal of Pure and Applied Microbiology, 2017
Group B Streptococcus (GBS) is an opportunistic harmless bacterium which the leading cause of neonatal infections. Our purpose was to determine capsular genotypes distribution and antibiotic resistance pattern of GBS isolated from clinical samples. Two hundred and twenty two GBS strains isolated from clinical samples from different hospitals in Tehran, Iran. After identification by specific cultures and biochemical tests, broth microdilution method was used to determine the minimal inhibitory concentration (MIC) of antibiotics based on standard protocol. The erythromycin-clindamycin doubledisk test was used to determine the inducible resistance phenotypes. Capsular genotypes were identified by PCR method. The high rates of antibiotic resistance in GBS were related to gentamycin 89.18%, tetracycline 87.38%, kanamycin 62.16%, clindamycin (67.1%), erythromycin 57.2%, and chloramphenicol 32.8%. All strains were sensitive to vancomycin, penicillin, and ampicillin. Between eleven capsular antigens, serotypes such as III(50.9%) ,V(27.47%) ,Ib(17.76%) ,Ia(15.54%) , Ic (5.85%)were the highest. The genotypes distribution and the patterns of resistance phenotypes of GBS may vary in different areas. Thus, it is required to be considered in each region to work out strategies for prevention. The PCR method is recommended as a rapid and reliable technique for identification and molecular epidemiology study of GBS.
Therapeutic Advances in Infectious Disease
Streptococcus agalactiae, a Gram-positive bacterium, causes invasive infection known as Group B streptococcal disease (GBS). It is a leading cause of neonatal death and complications prior to delivery. The burden of GBS is unknown in India despite the high incidence of preterm and stillbirths. In this study, we performed a narrative review of the available literature (published in the last 10 years) on the epidemiology of GBS, using PubMed and Google Scholar, to understand its impact in India and evaluate potential strategies to prevent the disease in the high-risk population, that is, neonates. The review showed that the incidence of early- and late-onset GBS in neonates (per 1000 live births) was in the ranges of 0.090–0.68 and 0.0–0.07 respectively. The overall case fatality rate reported in only one study was 0.63. In pregnant women, the prevalence of GBS colonization was 2–62% and its transmission to their newborns varied from 6.7% to 11.1%. The serotype distribution of GBS is ...