Capsular Polysaccharide Types of Group B Streptococcal Isolates from Neonates with Early‐Onset Systemic Infection

Lin, Chin-Fu; Clemens, John D.; Azimi, Parvin H.; Regan, Joan A.; Weisman, Leonard E.; Philips, Joseph B.; Rhoads, George G.; Clark, Penny; Brenner, Ruth A.; Ferrieri, Patricia

doi:10.1086/517810

Cited by 80 publications

(58 citation statements)

References 13 publications

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“…Our data are consistent with other reports on serotypes typically associated with human and bovine S. agalactiae infections. While serotypes I, II, and III were the most prevalent serotypes among isolates from human neonates with early-onset GBS infections in the 1970s (3), more recent studies have shown serotypes Ia and III are the most common serotypes currently associated with GBS infections among neonates (2,32). Serotype V strains emerged as a cause of human infections in 1985; these strains have been shown to currently cause the majority of GBS infections among nonpregnant adults in the United States (6,23).…”

Section: Discussionmentioning

confidence: 99%

Distribution of Serotypes and Antimicrobial Resistance Genes among Streptococcus agalactiae Isolates from Bovine and Human Hosts

et al. 2005

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To better understand the emergence and transmission of antibiotic-resistant Streptococcus agalactiae, we compared phenotypic and genotypic characteristics of 52 human and 83 bovine S. agalactiae isolates. Serotypes found among isolates from human hosts included V (48.1%), III (19.2%), Ia and Ib (13.5% each), and II (5.8%). Among isolates from bovine hosts, molecular serotypes III and II were predominant (53 and 14.5%, respectively). Four and 21 different ribotypes were found among human and bovine isolates, respectively. A combination of ribotyping and serotyping showed that two bovine isolates were indistinguishable from human isolates. Resistance to tetracycline and erythromycin was more common among human (84.6% and 26.9%, respectively) than bovine (14.5% and 3.6%, respectively) isolates. tetM was found in all tetracycline-resistant human isolates, while tetO was the predominant resistance gene among bovine isolates. tet genes were found among various ribotypes. ermB, ermTR, and mefA were detected among erythromycin-resistant human isolates, while ermB was the only erythromycin resistance determinant among isolates from bovine hosts. For isolates from human hosts, erythromycin resistance genes appeared to be associated with specific ribotypes. We conclude that (i) human and bovine S. agalactiae isolates represent distinct populations; (ii) human hostassociated S. agalactiae subtypes may occasionally be transmitted to bovines; (iii) while emergence of erythromycin and tetracycline resistance appears to largely occur independently among human and bovine isolates, occasional cross-species transfer of resistant strains or transmission of resistance genes between human-and bovine-associated subtypes may occur; and (iv) dissemination of antibiotic-resistant S. agalactiae appears to include both clonal spread of resistant strains as well as horizontal gene transfer.

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Section: Discussionmentioning

confidence: 99%

Distribution of Serotypes and Antimicrobial Resistance Genes among Streptococcus agalactiae Isolates from Bovine and Human Hosts

et al. 2005

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“…Several serotypes of GBS exist (9), but only a few (serotypes Ia, Ib, Ic, II, and III) are common causes of human disease. Over the past decade, several investigators reported an increasing proportion of GBS disease to be due to serotype V (GBS-V) (1,2,8,11,21). During the same period, several investigators also reported an increase in macrolide (erythromycin) and clindamycin resistance among GBS isolates from U.S. hospitals (1,13,15,17).…”

Section: Pulsed-field Gel Electrophoresis (Pfge) Was Performed On 122mentioning

confidence: 99%

Molecular Epidemiology of Macrolide Resistance in Neonatal Bloodstream Isolates of Group B Streptococci

Diekema¹,

Andrews

Huynh³

et al. 2003

J Clin Microbiol

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Pulsed-field gel electrophoresis (PFGE) was performed on 122 neonatal bloodstream isolates of group B streptococci (GBS) to further examine the relationship between macrolide resistance and serotype V GBS (GBS-V).Over one-third (35%) of macrolide-resistant GBS belonged to a single PFGE subtype of GBS-V, which was also the most common GBS-V subtype noted in previous Centers for Disease Control and Prevention surveillance studies. Erm methylase (ermA and ermB) was the most common resistance mechanism detected, present in 12 of 20 macrolide-resistant GBS.Group B streptococci (GBS) cause significant morbidity and mortality in neonates and can also cause serious infections in adults (20,21). Several serotypes of GBS exist (9), but only a few (serotypes Ia, Ib, Ic, II, and III) are common causes of human disease. Over the past decade, several investigators reported an increasing proportion of GBS disease to be due to serotype V (GBS-V) (1,2,8,11,21). During the same period, several investigators also reported an increase in macrolide (erythromycin) and clindamycin resistance among GBS isolates from U.S. hospitals (1,13,15,17). In addition, several groups (including ours) have recently reported an association between macrolide resistance and GBS-V (1, 10, 12). It was found that, though GBS-V accounted for only ϳ10% of neonatal GBS bloodstream isolates, 40% of erythromycin-resistant and 83% of clindamycin-resistant strains were GBS-V (1).To further investigate the association between macrolidelincosamide resistance and the emergence of GBS-V, we performed pulsed-field gel electrophoresis (PFGE) analysis of the SmaI chromosomal DNA digests of 122 neonatal bloodstream isolates of GBS for which antimicrobial susceptibilities and serotype distribution had previously been described (1). To determine if macrolide-resistant GBS-V represented a new subtype, we included a strain previously characterized by Elliott and colleagues (6) at the Centers for Disease Control and Prevention (CDC) and found to be the most common GBS-V PFGE pattern detected in the United States (representing 56% of isolates collected between 1986 and 1996).The GBS bloodstream isolates in this study were collected as part of the SENTRY antimicrobial surveillance program (1). This report focuses on all neonatal bloodstream isolates of GBS obtained between January 1997 and December 1999 from 35 medical centers throughout the Western Hemisphere.Upon receipt at the University of Iowa, GBS isolates were subcultured onto blood agar to ensure viability and purity. Confirmation of species identification was performed by conventional methods: all GBS in our study were confirmed by the Christie-Atkins-Munch-Petersen test. Antimicrobial susceptibility testing was performed by reference broth microdilution methods as described by the National Committee for Clinical Laboratory Standards (NCCLS) (14).Serotyping was performed by an agglutination test with rabbit antisera to serotypes Ia, Ib, II, III, IV, and V, as described previously (1). For PFGE analysis, genomic DNA w...

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“…A serotype distribution based on the serotypes for one geographic location or small numbers of patients may not be generally applicable (9,17). Continued monitoring will be necessary to assess the suitability of combinations of GBS vaccine antigens for different target populations in different geographic locations (7,9).…”

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confidence: 99%

Serotype Identification of Group B Streptococci by PCR and Sequencing

et al. 2002

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Group B streptococcus (GBS; 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.

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Capsular Polysaccharide Types of Group B Streptococcal Isolates from Neonates with Early‐Onset Systemic Infection

Cited by 80 publications

References 13 publications

Distribution of Serotypes and Antimicrobial Resistance Genes among Streptococcus agalactiae Isolates from Bovine and Human Hosts

Distribution of Serotypes and Antimicrobial Resistance Genes among Streptococcus agalactiae Isolates from Bovine and Human Hosts

Molecular Epidemiology of Macrolide Resistance in Neonatal Bloodstream Isolates of Group B Streptococci

Serotype Identification of Group B Streptococci by PCR and Sequencing

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