Streptococcus agalactiae in Brazil: serotype distribution, virulence determinants and antimicrobial susceptibility

Genomic characterization of emerging invasive Streptococcus agalactiae serotype VIII in Alberta, Canada

Invasive Group B Streptococcus (GBS) can infect pregnant women, neonates, and older adults. Invasive GBS serotype VIII is infrequent in Alberta; however, cases have increased in recent years. Here, genomic analysis was used to characterize fourteen adult invasive serotype VIII isolates from 2009 to 2021. Trends in descriptive clinical data and antimicrobial susceptibility results were evaluated for invasive serotype VIII isolates from Alberta. Isolate genomes were sequenced and subjected to molecular sequence typing, virulence and antimicrobial resistance gene identification, phylogenetic analysis, and pangenome determination. Multilocus sequencing typing identified eight ST42 (Clonal Complex; CC19), four ST1 (CC1), and two ST2 (CC1) profiles. Isolates were susceptible to penicillin, erythromycin, chloramphenicol, and clindamycin, apart from one isolate that displayed erythromycin and inducible clindamycin resistance. All isolates carried genes for peptide antibiotic resistance, three isolates for tetracycline resistance, and one for macrolide, lincosamide, and streptogramin resistance. All genomes carried targets currently being considered for protein-based vaccines (e.g., pili and/or Alpha family proteins). Overall, invasive GBS serotype VIII is emerging in Alberta, primarily due to ST42. Characterization and continued surveillance of serotype VIII will be important for outbreak prevention, informing vaccine development, and contributing to our understanding of the global epidemiology of this rare serotype.

Genotype Distribution and Antibiotic Susceptibility Pattern of Clinical Isolates of Group B Streptococcus in a Tertiary Care Hospital in Puducherry, South India

Background

Streptococcus agalactiae apart from being a colonizer in the genital region is also associated with several other invasive infections in all age groups. With the varied distribution of serotypes across different regions of the world, universal vaccination is also unattainable. However, in India, the knowledge of group B Streptococcus (GBS) genotype distribution is deficient. Thus, this study was initiated to add data on this aspect. Methodology. A cross-sectional study was conducted using isolates of group B Streptococcus from all clinical specimens. Along with that, the clinical specimen type and the antibiotic resistance profile of the isolates were correlated with the genotypes recognized through a multiplex PCR assay.

Results

Among the 86 isolates subjected to multiplex PCR for genotype identification, five genotypes were identified with genotype Ib as the predominant one (34.9%), followed by III (20.9%), II (16.3%), Ia (12.7%), and V (11.6%).

Conclusion

The results demonstrated a correlation of types Ib and III with vaginal colonization and type II with urine specimens in the current study. This preliminary study exhibited the distribution of common genotypes and their antibiotic resistance profiles in various GBS isolates. However, multiple studies across the country with larger sample sizes are needed to validate these findings.

Changes in Group B Streptococcus Colonization among Pregnant Women before and after the Onset of the COVID-19 Pandemic in Brazil

Group B Streptococcus (GBS) is a leading cause of neonatal infections. The genitourinary and gastrointestinal tract of pregnant women are the main source of transmission to newborns. This work investigated the prevalence and characterized GBS from pregnant women in Rio de Janeiro, Brazil, comparing the periods before (January 2019 to March 2020; 521) and during (May 2020 to March 2021; 285) the COVID-19 pandemic. GBS was detected in 10.8% of anovaginal samples. Considering scenarios before and during the pandemic, GBS colonization rate significantly decreased (13.8% vs. 5.3%; p = 0.0001). No clinical and sociodemographic aspect was associated with GBS carriage (p > 0.05). A total of 80%, 13.8% and 4.6% GBS strains were non-susceptible to tetracycline, erythromycin and clindamycin, respectively. Serotype Ia was the most frequent (47.7%), followed by V (23.1%), II (18.4%), III (7.7%) and Ib (3.1%). An increasing trend of serotypes Ib and V, as well as of antimicrobial resistance rates, and a decreasing trend of serotypes II and III, were observed after the pandemic onset, albeit not statistically significant (p > 0.05). The reduction in GBS colonization rates and alterations in GBS serotypes and resistance profiles during the pandemic were not due to changes in the sociodemographic profile of the population. Considering that control and preventive measures related to the COVID-19 pandemic onset have impacted other infectious diseases, these results shed light on the need for the continuous surveillance of GBS among pregnant women in the post-pandemic era.

Genetic diversity and antimicrobial resistance of invasive, noninvasive and colonizing group B Streptococcus isolates in southern Brazil

Introduction. Group B Streptococcus (GBS) is a human commensal bacterium that is also associated with infection in pregnant and non-pregnant adults, neonates and elderly people.

Gap Statement. The authors hypothesize that knowledge of regional GBS genetic patterns may allow the use of prevention and treatment measures to reduce the burden of streptococcal disease.

Aim. The aim was to report the genotypic diversity and antimicrobial sensitivity profiles of invasive, noninvasive urinary and colonizing GBS strains, and evaluate the relationships between these findings.

Methodology. The study included consecutive and non-duplicated GBS isolates recovered in southern Brazil from 2015 to 2017. We performed multiple-locus variable-number tandem repeat analysis (MLVA) and PCR analyses to determine capsular serotypes and identify the presence of the resistance genes mefA/E, ermB and ermA/TR, and also antibiotic susceptibility testing.

Results. The sample consisted of 348 GBS strains, 42 MLVA types were identified, and 4 of them represented 64 % of isolates. Serotype Ia was the most prevalent (42.2 %) and was found in a higher percentage associated with colonization, followed by serotypes V (24.4 %), II (17.8 %) and III (7.8 %). Serotype V was associated with invasive isolates and serotypes II and III with noninvasive isolates, without significant differences. All isolates were susceptible to penicillin. GBS 2018/ hvgA was observed in 17 isolates, with 11 belonging to serogroup III. The Hunter–Gaston diversity index was calculated as 0.879. The genes mefA/E, erm/B and erm/A/TR were found in 45, 19 and 46 isolates.

Conclusion. This report suggests that the circulating GBS belong to a limited number of genetic lineages. The most common genotypes were Ia/MT12 and V/MT18, which are associated with high resistance to macrolides and the presence of the genes mefA/E and ermA/TR. Penicillin remains the antibiotic of choice. Implementation of continuous surveillance of GBS infections will be essential to assess GBS epidemiology and develop accurate GBS prevention, especially strategies associated with vaccination.

Laboratory diagnosis of bacterial meningitis by direct detection, serotyping and Next Generation Sequencing: How 10 years of testing in New York State has evolved to improve laboratory diagnosis and public health

Since 2005, the Wadsworth Center (WC) has provided molecular testing on cerebrospinal fluid (CSF) and whole blood specimens in close collaboration with epidemiologists in New York State and New York City. In this study, we analyzed 10 years of data to demonstrate the significant value of utilizing molecular methods to assess patient specimens for etiologic agents of bacterial meningitis. A comprehensive molecular testing algorithm to detect and serotype/serogroup bacterial agents known to cause bacterial meningitis (Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus agalactiae) has evolved, and retrospective specimen testing has been essential for each improvement. Over a ten-year span from 2010 to 2019 the WC received 831 specimens from 634 patients with suspected bacterial meningitis. Real-time PCR was positive for at least one of the agents in 223 (27%) specimens from 183 patients (29%). Of the 223 positives, 146 (66%) were further characterized by real-time PCR into serogroup/serotype. Additionally, examination of 131 paired specimens of CSF and whole blood from the same patients found better detection in CSF, but whole blood is a useful alternative for diagnosis when CSF is not available. For specimens initially PCR-negative, 16S rDNA Sanger sequencing was requested by the submitter for 146 cases resulting in the identification of bacterial agents in an additional 24 (16%) specimens. In a retrospective study, Next Generation Sequencing (NGS) was evaluated for the detection of pathogens in 53 previously tested PCR-negative CSF specimens and identified bacteria in 14 (26%) specimens. This molecular testing algorithm has provided clinicians a diagnosis when culture is negative with the potential to guide therapy. It has also aided public health in determining when antibiotic prophylaxis was needed, augmented surveillance data to yield a fuller picture of community prevalence, and highlighted gaps in the spectrum of agents that cause bacterial meningitis.

Distribution of virulence determinants in Streptococcus agalactiae recovered from different clinical sources

Streptococcus agalactiae (group B Streptococcus, GBS) is a pathobiont, a member of human microbiota that can change from commensal to pathogen, causing a large spectrum of diseases. This study assessed virulence determinants of 32 GBS isolates recovered from different clinical sources associated with asymptomatic and symptomatic clinical outcomes that present distinct capsular types and antimicrobial resistance profiles. The ability of a unique strain to colonize and cause infection in different subjects was also evaluated. By PFGE analysis, it was observed that a given strain could be associated with both asymptomatic and symptomatic outcomes. Cell wall anchor proteins β and alpha C encoding genes (bac and bca, respectively) were detected in all capsular type Ib isolates. bca was more frequent among asymptomatic outcome-related isolates, as well as high expression of β-hemolysin/cytolysin (β-H/C). Symptomatic outcome-related isolates produced strong biofilm more frequently. All bacterial isolates recovered from urine were strong biofilm producers. In growth experiments, asymptomatic outcome-related isolates grew faster after 2 h until the end of the log phase. Taken together, these findings show virulence genotypic and phenotypic features of GBS from distinct sources, which may be helpful to understand their pathogenic potential and predict different clinical outcomes.

Prevalence, Resistance Profile and Virulence Genes of Streptococcus agalactiae Colonizing Near-term Pregnant Women Attending Ain Shams University Hospital

Group B streptococcus (GBS) is a common cause of infections in pregnant females and non-pregnant adults with chronic diseases (such as diabetes and cancer), also it is the main reason of septicaemia and meningitis in infants. The aim of this study was to figure out how common GBS is in pregnant women, the antimicrobial sensitivity pattern of the isolated GBS colonies and check the presence of scpB and rib virulence genes in these isolates. We screened 203 pregnant women attending the Maternity Hospital of Ain Shams University using vaginal sampling. Isolation was done on CHROMagarTM Strep B and sheep blood agar plates then identified via colony characters, Gram stain, test for catalase production, Christie–Atkins–Munch-Petersen (CAMP) test, test for hippurate hydrolysis and latex agglutination test. This was followed by an antibiotic susceptibility test. Finally, Detection of scpB and rib virulence genes by conventional PCR was done. Our study detected that the prevalence rate of GBS in involved pregnant women was 11.33%. A statistically significant association between colonization and history of spontaneous abortion and preterm labor was observed. CHROMagar™ StrepB showed the same sensitivity of sheep blood agar with extensive effort to isolate suspected GBS colonies from blood agar. GBS was 100% sensitive to levofloxacin, linezolid, cefepime, ceftaroline and ceftriaxone. Also, it was highly sensitive to vancomycin (91.3%). Sensitivity to clindamycin, azithromycin, penicillin and ampicillin was (21.70%, 21.70%,47.80%, 47.80%) respectively. The least sensitivity of GBS was to erythromycin ( 8.7%). All isolates possessed the scpB gene (100%) while only 18 isolates (78.26%) had the rib gene.

Whole genome sequence based capsular typing and antimicrobial resistance prediction of Group B streptococcal isolates from colonized pregnant women in Nigeria

BACKGROUND

Streptococcus agalactiae (Group B Streptococcus, GBS) is one of the major bacterial pathogens responsible for neonatal sepsis. Whole genome sequencing has, in recent years, emerged as a reliable tool for capsular typing and antimicrobial resistance prediction. This study characterized vaginal and rectal isolates of Group B Streptococcus obtained from pregnant women in Port Harcourt, Nigeria using a whole-genome sequence-based approach.

RESULTS

Capsular types Ia, Ib, II, III, IV and V were detected among the 43 isolates sequenced. Twelve sequence types (STs) were identified, with ST19 (n = 9, 27.3 %) and ST486 (n = 5, 15.2 %) the most frequent among non-duplicated isolates. Of the alpha-like proteins (alp) identified, Alp1 was the most prevalent in 11 (33.3 %) isolates. Macrolide and lincosamide resistance determinants were present in 15 (45.5 %) isolates; ermB was detected in 1 (3 %), ermTR in 7 (21.2 %) isolates, lnu gene was detected in 6 (18.2 %) and mef was identified in 3 (9.1 %) isolates. Resistance of GBS to erythromycin and clindamycin (predicted from presence of erm or mef genes) was found to be 30.3 % and 24.2 %, respectively. All isolates were predicted resistant to tetracycline with only the tetM gene identified. Fluoroquinolone-resistance conferring substitutions in gyrA + parC were detected in 9 (27.3 %) isolates and chloramphenicol resistance was predicted from presence of aac6'-aph2 gene in 11 (33.3 %).

CONCLUSIONS

The data available from the whole genome sequencing of these isolates offers a small but insightful description of common serotypes and resistance features within colonizing GBS in Nigeria.

Antimicrobial Resistance among Beta-Hemolytic Streptococcus in Brazil: An Overview

Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus dysgalactiae subsp. equisimilis (SDSE) are the beta-hemolytic streptococci species with the most clinical relevance to humans. These species are responsible for several infections, ranging from mild to life-threatening diseases. Although resistance to recommended drugs has not been so critical as detected in other species, it has occurred in diverse regions. In Brazil, it is possible to observe an increasing macrolide and lincosamide resistance trend due to the spread of polyclonal strains. Macrolide-lincosamide-streptogramin B (MLS) resistance phenotypes have been prevalent among S. agalactiae and S. pyogenes, while M phenotype (resistance only to macrolides) has prevailed among SDSE resistant isolates. Fluoroquinolone resistance is rare in this country, reported only in S.agalactiae and S.pyogenes. This is due to nucleotide substitutions in gyrA and parC genes. Reduced penicillin susceptibility and vancomycin resistance, detected in other regions, have not yet been reported in Brazil. Tetracycline is not a therapeutical option, and resistance has occurred at high levels, especially among S.agalactiae. These findings highlight the need for continuous monitoring in order to track the occurrence of antimicrobial resistance among beta-hemolytic streptococci species circulating in this country.

Group B streptococcus drug resistance in pregnant women in Iran: a meta-analysis

Streptococcus (S.) agalactiae colonizes in the female genitourinary and lower gastrointestinal tracts and is responsible for a wide range of infections in newborns, pregnant women and non-pregnant adults. Therefore, antibiotic prophylaxis and infection treatment against S. agalactiae is important. The aim of this study was to determine the prevalence of S. agalactiae antibiotic resistance in Iranian patients, especially among pregnant women. A systematic literature search was conducted in PubMed, Scopus, Google Scholar and the Scientific Information Database (SID) databases by using related keywords and without any time limitation. A total of 26 studies reporting the prevalence of S. agalactiae antibiotic resistance in Iran met our predefined inclusion and exclusion criteria and were included in the meta-analysis. High rates of S. agalactiae antibiotic resistance in pregnant women were found against tetracycline (96.2%), trimethoprim-sulfamethoxazole (84.7%), cefotaxime (41.3%), clindamycin (26.8%) and erythromycin (21%). Additionally, resistance to penicillin (4.2%), ampicillin (2.7%), cefazolin (7.6%), vancomycin (2.4%), ceftriaxone (12.5%), ciprofloxacin (13.6%) and nitrofurantoin (0%) was low. Our results revealed that penicillin and ampicillin among penicillin-tolerant Iranian pregnant women, and vancomycin and cefazolin among penicillin-allergic women are still drugs of choice in intrapartum prophylaxis for preventing S. agalactiae vertical transmission and early-onset neonatal disease.

Capsular genotype distribution of Group B Streptococcus colonization among at-risk pregnant women in Sao Paulo, Brazil

BACKGROUND

Vaccines in development against Group B Streptococcus (GBS) should contain the most prevalent capsular genotypes screened in the target population. In low- and middle-income countries epidemiological data on GBS carriage among pregnant women, a prerequisite condition for GBS neonatal sepsis, is needed to inform vaccine strategies.

OBJECTIVE

To investigate the prevalence of different GBS capsular genotypes that colonizes at-risk pregnant women in a private maternity hospital in São Paulo, Brazil.

METHODS

GBS strains isolated in routine maternity procedures from at-risk pregnant women from 2014 to 2018 were confirmed by mass spectrometry (MALDI-TOF) with subsequent DNA extraction for identification of capsular genotype through polymerase chain reaction (PCR). Demographic and gestational data were analyzed.

RESULTS

A total of 820 Todd-Hewitt broths positive for GBS were selected for streptococcal growth. Recovery and confirmation of GBS by MALDI-TOF were possible in 352. Strains were processed for determination of capsular genotype by PCR. From the total of 352 GBS isolates, 125 strains (35.5%) were genotyped as Ia; 23 (6.5%) as Ib; 41 (11.6%) as II; 36 (10.2%) as III; 4 (1.1%) as IV; 120 (34.1%) as V and 1 strain (0.3%) as VIII. Two isolates (0.7%) were not genotyped by used methodology. No statistically significant correlation between gestational risk factors, demographic data and distribution of capsular genotypes were found.

CONCLUSIONS

GBS capsular genotypes Ia, Ib, II, III, and V were the most prevalent isolates colonizing at risk pregnant women in the present study. The inclusion of capsular genotypes Ia and V in the composition of future vaccines would cover 69.6% of capsular genotypes in the studied population. No statistically significant differences were observed between capsular genotype and gestational and demographic data and risk factors.

Molecular Characterization of Hospital- and Community-Acquired Streptococcus agalactiae Isolates among Nonpregnant Adults in Isfahan, Iran

Background:

The increasing incidence of Group B Streptococcus (GBS) infection among nonpregnant adults has become of growing clinical and public health concern. The current study investigated the distribution of important virulence determinants and antibiotic susceptibility of GBS isolates causing community acquired (CA) and hospital acquired (HA) infections among nonpregnant adults.

Materials and Methods:

A total of 62 GBS, including 31 CA GBS and 31 HA GBS, were collected from a teaching hospital in Isfahan, Iran. Capsular polysaccharide genotypes (CPS), PI 1, PI 2a, PI 2b, and hypervirulent GBS adhesin (hvgA) virulence genes and antibiotic resistance profiling were determined.

Results:

There were 19 (30.6%) cases of underlying disease that diabetes mellitus (20.9%) was most common. The rate of multidrug resistant GBS strains was accounted for 29%. Distribution of macrolide resistant phenotypes was as follows: constitutive macrolides, lincosamides, and streptogramin B (MLSB) (15 isolates); inducible resistance to MLSB; and L phenotype (each 5 isolates) and M phenotype (1 isolate). V and Ia serotypes were the most predominant capsular type in HA GBS and CA GBS isolates, respectively. The most frequent pilus types were PI 1, PI 1+PI 2a, PI 1+PI 2b, and PI 2a. PI 1 and PI 1+PI 2a had significantly different distributions between CA and HA GBS isolates. Three CA GBS isolates (9.6%) were positive for hvgA gene that belonged to clonal complex 17/sequence type 17/CPS III/PI 1+PI 2b lineage.

Conclusion:

There was a significant difference in the distribution of PIs among CA GBS and HA GBS isolates in our region.

Prevalence, serotypes and virulence genes of Streptococcus agalactiae isolated from pregnant women with 35-37 weeks of gestation

Background

In pregnant women Streptococcus agalactiae (GBS) can be transmitted to newborn causing severe infections. It is classified into 10 serotypes (Ia, Ib, II-IX). The severity of neonatal disease is determined by the capsular serotype and virulence factors such as the polysaccharide capsule, encoded by the cps gene, protein C, which includes the Cα surface proteins (bca gene), Rib (rib gene) and Cβ (bac gene); the proteins Lmb (lmb gene), FbsB (fbsB gene), FbsA (fbsA gene), the cyl operon encoding a β-hemolysin (hylB gene), the CAMP factor (cfb gene) and the C5a peptidase (scpB gene). The aim of this work was to determine the degree of GBS colonization in pregnant women, the serotypes distribution and to investigate virulence-associated genes.

Methods

We worked with 3480 samples of vagino-rectal swabs of women with 35–37 weeks of gestation. The identification of the strains was carried out using conventional biochemical tests and group confirmatory serology using a commercial latex particle agglutination kit. Two hundred GBS strains were selected. Their serotype was determined by agglutination tests. The monoplex PCR technique was used to investigate nine virulence-associated genes (cps, bca, rib, bac, lmb, fbsB, fbsA, hylB and scpB).

Results

The maternal colonization was 9.09%. The serotypes found were: Ia (33.50%), III (19.00%), Ib (15.50%), II (14.00%), V (7.00%) and IX (5.50%). 5.50% of strains were found to be non-serotypeable (NT). The nine virulence genes investigated were detected simultaneously in 36.50% of the strains. The genes that were most frequently detected were scpB (100.00%), fbsA (100.00%), fbsB (100.00%), cylB (95.00%), lmb (94.00%) and bca (87.50%). We found associations between serotype and genes bac (p = 0.003), cylB (p = 0.02), rib (p = 0.01) and lmb (p < 0.001).

Conclusions

The frequency of vaginal-rectal colonization, serotypes distribution and associated virulence genes, varies widely among geographical areas. Therefore, epidemiological surveillance is necessary to provide data to guide decision-making and planning of prevention and control strategies.

Trends in molecular characteristics and antimicrobial resistance of group B streptococci: a multicenter study in Serbia, 2015-2020

Group B Streptococcus (GBS) is a major cause of neonatal morbidity and mortality. Serbia has not fully implemented preventive measures against GBS neonatal diseases. Therefore, we aimed to assess the maternal GBS colonisation and invasive neonatal disease rate, to reveal the trends of antimicrobial resistance and serotype distribution of GBS from various patient groups. Randomly selected non-invasive (n = 991) and all invasive GBS (n = 80) collected throughout Serbia from 2015 to 2020 were tested for antimicrobial susceptibility, capsular typing, and hvgA detection. Overall, 877/5621 (15.6%) pregnant women were colonised with GBS. Invasive GBS infections incidence in infants (0.18/1000 live births) showed a decreasing trend (0.3 to 0.1/1000 live births). Type III was overrepresented in infants with invasive infections (n = 35, 58.3%), whereas type V predominated among colonised adults (n = 224, 25.5%) and those with noninvasive (n = 37, 32.5%) and invasive infections (n = 8, 40%). The hypervirulent clone III/ST17 was highly associated with invasive infections (n = 28, 35%), particularly late-onset disease (n = 9, 47.4%), showing an increase from 12.3 to 14.8%. The GBS resistance to erythromycin and clindamycin was 26.7% and 22.1%, respectively, with an upward trend. The emergence of the hypervirulent clone III/ST17 and the escalation in GBS resistance highlight an urgent need for continuous monitoring of GBS infections.

Streptococcus agalactiae strains isolated from cancer patients in Rio de Janeiro, Brazil

Streptococcus agalactiae is a recognized pathogen associated with infections in neonates, elderly, and immunocompromised adults, particularly those with cancer. In the present investigation, clinical-epidemiological features, multidrug resistance profiles, and virulence genes of S. agalactiae strains isolated from cancer patients were investigated. S. agalactiae capsular distribution assays demonstrated that Ia (43.6%) and V (23.6%) types were predominantly detected among 55 clinical isolates tested; only one strain (GBS1428) was capsular type III/ST-17. The fbsB and hylB genes were detected in all isolates, while the iag, lmb, and fbsA genes were detected in 94.5%, 91%, and 91% of oncological isolates, respectively. The combination of PI-1 and PI-2a was the most common (60%) among S. agalactiae strains isolated from oncologic patients. S. agalactiae strains were resistant to tetracycline (85.5%), erythromycin (9%), and clindamycin (5.5%). Norfloxacin non-susceptible was detected in 7.3% of S. agalactiae strains. Our findings reinforce the need for S. agalactiae control measures in Brazil, including cancer patients.

Streptococcus agalactiae: Sensitivity profile in pregnant women attending health units in northeastern Brazil

BACKGROUND

Group B Streptococcus agalactiae (GBS) is the main etiologic agent associated with early-onset neonatal sepsis, and of all newborns of parturients colonized by GBS, approximately 1%-2% develop invasive, early-onset disease. The risk of infection increases to 15.2% in premature neonates, to 10.7% when the parturient has chorioamnionitis or premature rupture of membranes for more than 24 h and to 9.7% if the mother has postpartum bacteremia. In addition to causing perinatal, neonatal and postnatal deaths, neonatal hospital infection is associated with high costs, as hospitalization is three times longer than in uninfected children. The identification of pregnant women colonized by GBS, through universal screening, associated with the adoption of appropriate antibiotics at the time of delivery are the most successful preventive measures.

AIM

To evaluate the sensitivity profile of GBS isolated from pregnant women attending Vitória da Conquista-BA.

METHODS

This is a cross-sectional study with a quantitative approach carried out in the municipality of Vitória da Conquista-Bahia between February 2017 and March 2018. The study population was composed of 210 pregnant women, with a gestational age of 32 to 40 wk, who were aged 18 years or older living in the urban area of the municipality of Vitória da Conquista. After a brief explanation about the research and obtaining a signed an informed consent form, data and vaginorectal swabs were collected from the women for GBS research. Examination of the samples in order to identify the presence of GBS was by culture on sheep blood agar and chromogenic agar for GBS and then, seeded on plates containing streptococcal culture medium and incubated for 18 h to 24 h at 35°C. The antimicrobial sensitivity profile of positive GBS samples was determined by the disk diffusion technique, according to the Clinical and Laboratory Standards Institute manual (2017). The data obtained were stored in a database using Microsoft Office Excel spreadsheets and a descriptive analysis was performed with the aid of the EPI-INFO statistical package (version 3.5.2).

RESULTS

Among the 210 pregnant women participating in the study, 38 (18.1%) had a positive GBS culture. All strains isolated from GBS were sensitive to 10 U penicillin, 10 µg ampicillin, 30 µg cefotaxime and 30 µg vancomycin. Seven strains (18.4%) resistant to clindamycin 2 µg and eight (21.1%) resistant to erythromycin 15 µg were found. Of these, six were concomitantly resistant to erythromycin and clindamycin, two resistant only to erythromycin and one resistant only to clindamycin. All nine GBS isolates that showed resistance to erythromycin and/or clindamycin showed negative results on the D-test. Two thirds of the isolates showed cMLSB phenotype and resistance only to erythromycin in specimens in this study (02), refers to strains with phenotype M and resistance to clindamycin (01) only with phenotype L.

CONCLUSION

Chemoprophylaxis for GBS in pregnant women, especially for those allergic to penicillin, should be guided by an antimicrobial susceptibility test as resistant GBS strains were reported in this study.

Association of sexually-transmitted infection and African-American race with Streptococcus agalactiae colonization in pregnancy

Background

Group B Streptococcus (GBS) remains a significant cause of neonatal infection, but the maternal risk factors for GBS colonization remain poorly defined. We hypothesized that there may be an association between antibiotic exposure during pregnancy and GBS colonization and/or the presence of inducible clindamycin resistance (iCLI-R) in GBS isolates from GBS-colonized pregnant women.

Methods

A retrospective cohort study was performed at Louisiana State University Health Sciences Center – Shreveport including demographic and clinical data from 1513 pregnant women who were screened for GBS between July 1, 2009 and December 31, 2010.

Results

Among 526 (34.8%) women who screened positive for GBS, 124 (23.6%) carried GBS strains with iCLI-R (GBS-iCLI-R). While antibiotic exposure, race, sexually-transmitted infection (STI) in pregnancy, GBS colonization in prior pregnancy and BMI were identified as risk factors for GBS colonization in univariate analyses, the only independent risk factors for GBS colonization were African–American race (AOR = 2.142; 95% CI = 2.092–3.861) and STI during pregnancy (AOR = 1.309; 95% CI = 1.035–1.653). Independent risk factors for GBS-iCLI-R among women colonized with GBS were non-African–American race (AOR = 2.13; 95% CI = 1.20–3.78) and younger age (AOR = 0.94; 95% CI = 0.91–0.98). Among GBS-colonized women with an STI in the current pregnancy, the only independent risk factor for iCLI-R was Chlamydia trachomatis infection (AOR = 4.31; 95% CI = 1.78–10.41).

Conclusions

This study identified novel associations for GBS colonization and colonization with GBS-iCLI-R. Prospective studies will improve our understanding of the epidemiology of GBS colonization during pregnancy and the role of antibiotic exposure in alterations of the maternal microbiome.

Clinical characteristics and molecular epidemiology of invasive Streptococcus agalactiae infections between 2007 and 2016 in Nara, Japan

Invasive Streptococcus agalactiae (GBS) infections are increasingly common among neonates and the elderly. Therefore, GBS surveillance for better antibiotic treatment and prophylaxis strategies are needed. We retrospectively evaluated the clinical aspects of invasive infections and the phenotypic and genetic diversity of infectious isolates from Nara, Japan, collected between 2007 and 2016, by using information from hospital records. GBS strains collected from the blood and cerebrospinal fluid cultures were evaluated for capsular types, multi-locus sequence typing (MLST), antibiotic susceptibility, antibiotics resistance gene, and pulsed-field gel electrophoresis. Forty GBS isolates (10 from children and 30 from adults) were analyzed, and the distribution of molecular serotype and allelic profiles varied between children and adults. We found the rates of early-onset disease in neonates with birth complications to be higher than that of previous reports, indicating that there could be relevance between complications at birth and early-onset disease. Standard antibiotic prophylaxis strategies may need to be reconsidered in patients with birth complications. In adults, the mean age of the patients was 68 years (male: 63%). Primary bacteremia was the most common source of infection. In the neonates, six had early-onset diseases and four had late-onset diseases. The most frequently identified strains were molecular serotype Ia ST23 (40%) and molecular serotype Ib ST10 (20%) in children and molecular serotype Ib ST10 (17%), molecular serotype VI ST1 (13%), and molecular serotype V ST1 (13%) in adults. Levofloxacin-resistant molecular serotype Ib strains and molecular serotypes V and VI ST1 were common causes of GBS infection in adults but were rarely found in children. Furthermore, pulsed-field gel electrophoresis in our study showed that specific clone isolates, that tend to have antibiotics resistance were widespread horizontally for a decade. Continuous surveillance and molecular investigation are warranted to identify the transmission route and improve antibiotic treatment strategies.

Phylogeny, recombination, and invasiveness of group B Streptococcus revealed by genomic comparisons of its global strains

Capsular polysaccharide (CPS) genes and pilus islands encode important virulence factors for group B Streptococcus (GBS) genomes. This study aims to detect phylogenetic inconsistency in CPS genes and pilus islands in GBSs and to explore its relationship with invasiveness. A total of 1016 GBS genomes were downloaded from the NCBI public database. The multi-locus sequence typing (MLST) and Bayesian analysis of Population Structure (BAPS) analyses were both conducted for phylogeny construction. Serotyping and pilus typing were determined in silico using the genomic sequences. The CPS and pilus typing results were generally consistent with MLST and BAPS clustering. GBS isolates of serotype II and of the PI-1 + PI-2b and PI-2a types were more prone to phylogenetic inconsistency than the others. Isolates of serotype Ib and of PI-1 + PI-2a were more likely to appear as colonizing strains, whereas PI-2b was more likely to appear in invasive strains. For serotype V, phylogenetic inconsistency occurred more commonly in colonizing isolates, while for serotype III, the opposite occurred. The present study profiles for the first time the phylogenetic inconsistency of CPS genes and pilus islands in global GBS isolates, which is helpful for infection control and the development of new vaccines for the prevention of GBS occurrence.

Streptococcus agalactiae: Identification methods, antimicrobial susceptibility, and resistance genes in pregnant women

BACKGROUND

Group B Streptococcus (GBS) is a normal component of the gastrointestinal and genital microbiota in humans and can lead to important infections in newborns.

AIM

To compare GBS isolation and identification methods as well as to assess the antibiotic susceptibility and to identify resistance genes in GBS strains from pregnant women attended in healthcare services from the city of Vitória da Conquista, in Bahia State, Brazil.

METHODS

From January 2017 to February 2018, vaginorectal swabs were obtained from 186 participants and the samples were seeded onto chromogenic agar for GBS before and after inoculation in selective broth. Confirmatory identification using 3 CAMP and latex tests was performed in samples with GBS-suggestive colonies. Then, disk diffusion antibiograms were performed in GBS-positive samples, and the detection of the resistance genes ermB, ermTR, mefA, and linB in the clindamycin and/or erythromycin-resistant samples was carried out.

RESULTS

Thirty-two samples (17.2%) were GBS-positive. The culture in chromogenic agar after sample incubation in selective broth was the most sensitive method (96.9%) for GBS detection. All isolates were susceptible to penicillin, ampicillin, cefotaxime, and vancomycin. Clindamycin resistance was observed in 6 samples (18.8%), while 8 samples (25%) were erythromycin-resistant. All erythromycin and/or clindamycin-resistant GBS strains had negative D-tests. Two strains (25%) presented an M phenotype and 6 isolates (75%) presented a cMLSB phenotype. The ermB gene was identified in 4 samples (44.4%), the mefA gene was also found in 4 samples (44.4%), the ermTR gene was identified in 1 isolate (11.1%), and the linB gene was not found in any isolate.

CONCLUSION

This study evidenced that the screening for SGB can be performed by means of various methods, including chromogenic media, and that the chemoprophylaxis for pregnant women who cannot use penicillin must be susceptibility-guided.

Increasing Resistance and Changes in Distribution of Serotypes of Streptococcus agalactiae in Poland

Streptococcus agalactiae is responsible for serious infections in newborn babies, pregnant women, and other patients. The aim of this study was to evaluate antimicrobial susceptibility, serotype distribution, and virulence determinants of the S. agalactiae isolates derived from clinical specimens considering the global increase of both antibiotic resistance and virulence. A total of 165 isolates were identified and serotyped by PCR techniques. Antimicrobial susceptibility was assessed by disk diffusion method, gradient diffusion method and VITEK^® System. Virulence associated genes were investigated by PCR; ability to form biofilm was assessed using a microtiter plate assay. The highest observed MIC value for penicillin G was 0.12 µg/mL, seen in 8.5% of isolates. Resistance to erythromycin and clindamycin were found in 30.38% and 24.8% of the strains, respectively. The serotype III (32.73%), V (25.45%), and Ia (18.18%) were found as the most frequently represented. Previously unidentified strains in Poland, belonging to serotypes VI (three strains) and VII (one strain) were recognized. The presence of genes encoding various virulence factors as well as diverse ability to form biofilm were found. In conclusion, macrolide-resistance and decreased susceptibility to penicillin G were revealed signifying the increasing resistance among group B streptococci. Moreover, the presence of genes encoding various virulence factors and the ability to form biofilm were confirmed indicating their role in the pathomechanisms of the evaluated GBS infections.

Antibiotic Resistance and Molecular Epidemiological Characteristics of Streptococcus agalactiae Isolated from Pregnant Women in Guangzhou, South China

Streptococcus agalactiae colonization in pregnant women can cause postpartum intrauterine infections and life-threatening neonatal infections. To formulate strategies for the prevention and treatment of S. agalactiae infections, we performed a comprehensive analysis of antibiotic resistance and a molecular-based epidemiological investigation of S. agalactiae in this study. Seventy-two S. agalactiae strains, collected from pregnant women, were subjected to antibiotic susceptibility tests; then, the screened erythromycin and clindamycin nonsusceptible isolates were used for macrolides and clindamycin resistance genes detection, respectively. Detection of resistance genes, serotyping, and determination of virulence genes were performed by polymerase chain reaction. The clonal relationships among the colonized strains were evaluated by multilocus sequence typing. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) mass peak analysis was performed to discriminate the specific sequence types (STs). In our study, 69.4% and 47.2% of the strains were nonsusceptible to erythromycin and clindamycin, respectively; the multidrug resistance rate was 66.7%. All erythromycin nonsusceptible strains harbored resistance genes, whereas only 52.9% of the clindamycin nonsusceptible strains possessed the linB gene. Erythromycin resistance was mainly mediated by the ermB or mefA/E genes. Four serotypes were identified, and the most common serotype was serotype III (52.8%), followed by Ib (22.2%), Ia (18.0%), and II (4.2%). All the strains were divided into 18 STs that were assigned to nine clonal complexes. Most of the major STs were distributed into specific serotypes, including ST19/serotype III, ST17/serotype III, ST485/serotype Ia, ST862/serotype III, and ST651/serotype III. Analysis of virulence genes yielded seven clusters, of which bca-cfb-scpB-lmb (61.6%) was the predominant virulence gene cluster. Among all ST strains distributed in this region, only the ST17 strains had a mass peak at 7620 Da. The outcomes of this study are beneficial for the epidemiological comparison of colonized S. agalactiae in different regions and may be helpful for developing the strategies for the prevention of S. agalactiae infection in Guangzhou. Furthermore, our results show that MALDI-TOF MS can be used for the rapid identification of the ST17 strains.

Phenotypic and Genotypic Characterization of Resistance to Macrolides and Lincosamides in Streptococcus agalactiae Isolated from Pregnant Women in Misiones, Argentina

The aim of this work was to determine the susceptibility, molecular profile, and clonal relationship in Streptococcus agalactiae (group B Streptococcus [GBS]) isolated from vaginal-rectal swab samples. We worked with 200 isolates collected from pregnant women between 35 and 37 weeks of gestation. The macrolide-lincosamide-streptogramin B (MLS_B) resistance phenotypes were determined using the double-disc assay. Susceptibility to erythromycin (ERI) and clindamycin (CLI) was performed with the E-test. Resistance genes ermB and ermTR were detected by polymerase chain reaction. Clonal studies were performed using the random amplification of polymorphic DNA. Twelve (6%) of the isolates were resistant to ERI and 10 (5%) of them to CLI. Fifty percent of the resistant strains corresponded to serotype III, 25% to serotype V, and the remaining 25% to serotype Ia, II, and nontypeable strains. The cMLS_B phenotype was detected in eight strains (66.67%) and the iMLS_B phenotype in four (33.33%). The minimum inhibitory concentration values were between 1.5 and 16 μg/mL for ERI, and between 1 and 32 μg/mL for CLI. Out of the 25 strains susceptible to ERI and CLI, the presence of the ermB gene was detected in eight of them and the ermTR gene in one strain. The ermB gene was detected in the 12 strains that initially had some macrolide resistance phenotype. The ermTR gene was detected in three out of the four strains with the iMLS_B phenotype. The resistance to macrolides in the province of Misiones is due to multiclonal spread. The phenotypic and genotypic characterization of macrolide resistance in GBS strains are crucial to contribute to the correct intrapartum prophylactic antibiotic therapy of allergic pregnant women and the epidemiological surveillance of these strains.

Prevalence, antimicrobial susceptibility patterns, serotypes and risk factors for group B streptococcus rectovaginal isolates among pregnant women at Kenyatta National Hospital, Kenya; a cross-sectional study

BACKGROUND

Estimates of Group B Streptococcus (GBS) disease burden, antimicrobial susceptibility, and serotypes in pregnant women are limited for many resource-limited countries including Kenya. These data are required to inform recommendations for prophylaxis and treatment of infections due to GBS.

METHODS

We evaluated the prevalence, antimicrobial susceptibility patterns, serotypes, and risk factors associated with rectovaginal GBS colonization among pregnant women receiving antenatal care at Kenyatta National Hospital (KNH) between August and November 2017. Consenting pregnant women between 12 and 40 weeks of gestation were enrolled. Interview-administered questionnaires were used to assess risk factors associated with GBS colonization. An anorectal swab and a lower vaginal swab were collected and cultured on Granada agar for GBS isolation. Positive colonies were tested for antimicrobial susceptibility to penicillin G, ampicillin, vancomycin, and clindamycin using the disk diffusion method. Serotyping was performed by latex agglutination. Logistic regression was used to identify factors associated with GBS colonization.

RESULTS

A total of 292 women were enrolled. Median age was 30 years (Interquartile range {IQR} 26-35) and a median gestational age of 35 weeks (IQR 30-37). Overall GBS was identified in 60/292 (20.5%) of participants. Among the positive isolates, resistance was detected for penicillin G in 42/58 (72.4%) isolates, ampicillin in 32/58 (55.2%) isolates, clindamycin in 14/46 (30.4%) isolates, and vancomycin in 14/58 (24.1%) isolates. All ten GBS serotypes were isolated, and 37/53 (69.8%) of GBS positive participants were colonized by more than one serotype. None of the risk factors was associated with GBS colonization.

CONCLUSION

The prevalence of GBS colonization was high among antenatal women at KNH. In addition, a high proportion of GBS isolates were resistant to commonly prescribed intrapartum antibiotics. Hence, other measures like GBS vaccination is a potentially useful approaches to GBS prevention and control in this population. Screening of pregnant mothers for GBS colonization should be introduced and antimicrobial susceptibility test performed on GBS positive samples to guide antibiotic prophylaxis.

Determinants of Group B streptococcal virulence potential amongst vaginal clinical isolates from pregnant women

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a Gram-positive bacterium isolated from the vaginal tract of approximately 25% of women. GBS colonization of the female reproductive tract is of particular concern during pregnancy as the bacteria can invade gestational tissues or be transmitted to the newborn during passage through the birth canal. Infection of the neonate can result in life-threatening pneumonia, sepsis and meningitis. Thus, surveillance of GBS strains and corresponding virulence potential during colonization is warranted. Here we describe a panel of GBS isolates from the vaginal tracts of a cohort of pregnant women in Michigan, USA. We determined that capsular serotypes III and V were the most abundant across the strain panel, with only one isolate belonging to serotype IV. Further, 12.8% of strains belonged to the hyper-virulent serotype III, sequence type 17 (ST-17) and 15.4% expressed the serine rich repeat glycoprotein-encoding gene srr2. Functional assessment of the colonizing isolates revealed that almost all strains exhibited some level of β-hemolytic activity and that ST-17 strains, which express Srr2, exhibited increased bacterial adherence to vaginal epithelium. Finally, analysis of strain antibiotic susceptibility revealed the presence of antibiotic resistance to penicillin (15.4%), clindamycin (30.8%), erythromycin (43.6%), vancomycin (30.8%), and tetracycline (94.9%), which has significant implications for treatment options. Collectively, these data provide important information on vaginal GBS carriage isolate virulence potential and highlight the value of continued surveillance.

Genomic characterisation of perinatal Western Australian Streptococcus agalactiae isolates

As a leading cause of neonatal sepsis, Streptococcus agalactiae, commonly known as Group B Streptococcus, is a major neonatal pathogen. Current global screening practices employ risk- or culture-based protocols for detection of these organisms. In Western Australia (WA), universal culture-based screening is provided, with subsequent intrapartum antibiotic prophylaxis for all S. agalactiae-positive women during labour. Widespread antibiotic exposure is not ideal and this is one of the factors driving development of vaccines against S. agalactiae. Vaccine candidates have focused on the capsule, surface proteins and pilus types, however, capsule serotypes are known to vary geographically. The aim of this study was to use genome sequencing to gain an understanding of the circulating genotypes in WA, and to assess variations in the associated gene pools. We sequenced 141 antenatal carriage (vaginal/rectal) isolates and 10 neonatal invasive disease isolates from WA. Based on the global PubMLST database, the 151 strains were characterised into 30 sequence types, with clustering of these mainly into clonal complexes 1, 12, 17, 19 and 23. Of the genes encoding eleven surface proteins that were analysed, the most prevalent were fbp, lmb and scpB which were present in ≥ 98% of isolates. A cluster of non-haemolytic isolates, one of which was a neonatal invasive disease isolate, appeared to lack the entire cyl locus. Admixture analysis of population structure revealed evidence of genetic transfer among the WA isolates across structural groups. When compared against the PubMLST S. agalactiae data, WA isolates showed high levels of strain diversity with minimal apparent clustering. This is the first whole genome sequence study of WA S. agalactiae isolates and also represents the first addition of Australian isolate data to PubMLST. This report provides insight into the distribution and diversity of vaccine targets of S. agalactiae within Western Australia, indicating that the most appropriate capsular vaccine for this population would be the proposed pentavalent (Cps Ia, Ib, II, III and V) preparation, whilst vaccines targeting surface proteins should ideally utilise Fbp, Lmb and/or ScpB.

Biofilm production and distribution of pilus variants among Streptococcus agalactiae isolated from human and animal sources

Streptococcus agalactiae (group B Streptococcus, GBS) is a major pathogen in humans and animals. Pili and biofilm may be important virulence factors in this bacterial species. Here, biofilm production and the distribution of pilus variants among 134 GBS isolates from human and animal sources were evaluated. Biofilm production was significantly enhanced in 1% glucose-supplemented medium (p < 0.05). Using this medium, most GBS strains were strong biofilm producers. Biomass was mainly composed of proteins, followed by extracellular DNA, while polysaccharides represented a minor portion. All GBS strains presented at least one pilus variant. PI-2a was the most common among human GBS while PI-2b was the most common among animal isolates. Human GBS harboring PI-2b and animal GBS harboring PI-2a presented significantly reduced biofilm production (p = 0.0033). In conclusion, strong biofilm production seems to be a common characteristic in GBS, and association of the clinical source with the pilus variant may be crucial for this.

Comparative multi-omics systems analysis reveal the glycolysis / gluconeogenesis signal pathway play an important role in virulence attenuation in fish-derived GBS YM001

Streptococcus agalactiae(GBS) is a seriously threat to the farmed tilapia, and oral vaccination was considered to be the most desirable means which requires deep understanding of virulence mechanism of the fish-derived GBS. Our previous genome study of the fish-derived attenuated strain YM001 showed that there were two large deletions in YM001 compared to its parental virulent strain HN016. In this study, a combined transcriptomic and proteomic analysis was performed on YM001 and HN016 strains, and the important genes were verified by RT-qPCR in bacteria strains and infected-tilapia tissues. Overall, we have shown that a total of 958 genes and 331 proteins were significantly differential expressed between YM001 and HN016. By functional annotation of these DEGs and DEPs, genes that were enriched in pentose phosphate pathway(pgm, ptsG, pgi pfkA, fbaA and FBP3) and pyruvate metabolism pathway(pdhA, pdhB, pdhC and pdhD) were identifed as important candidate genes for leads low growth ability in attenuated strain, which may be an important reasons leading virulence attenuation in the end. The expression levels the candidate genes in pentose phosphate pathway and pyruvate metabolism pathway were significant differential expressed in tilapia’ brain and spleen when infected with YM001 and HN016. Our study indicated that the pentose phosphate pathway and pyruvate metabolism pathway that affecting the growth of the strain may be one of the important reasons for the virulence attenuation in HN016.

Streptococcus agalactiae in pregnant women in Brazil: prevalence, serotypes, and antibiotic resistance

Brazilian data for maternal GBS colonization shows different prevalence rates. This conflicting data may be related to the absence of an official recommendation from the Federal Brazilian Health Authorities describing guidelines and protocols to perform GBS screening in pregnant women, in both public and private clinics. In the present review, we evaluated published reports addressing the prevalence of GBS in different regions of the country, methods used, and, when available, information regarding antibiotic resistance and serological typing of clinical isolates. According to this review, GBS prevalence in pregnant women in Brazil ranged from 4.2 to 28.4%, in the last 10 years. Serotype Ia was the most prevalent. The highest antibiotic resistance rates were found for tetarcycline, although its use to treat GBS infections is not common. Our results also show high resistance rates to clindamycin and erythromycin, which are commonly used as an alternative to penicillin in GBS infecctions. The increased antibiotic resistance, variations in serotype distribution, and high GBS prevalences need to be further investigated. Based on the present situation, recommendations regarding GBS surveillance in the country were raised and may improve our strategies for preventing neonatal infections.

Determination of surface proteins profile, capsular genotyping, and antibiotic susceptibility patterns of Group B Streptococcus isolated from urinary tract infection of Iranian patients

Objectives

Group B Streptococcus (GBS) is an important opportunistic bacteria that causes a wide range of infections including neonatal sepsis, meningitis, pneumonia, soft tissue and urinary tract infections (UTI). The aim of this study was to evaluate the antimicrobial susceptibility patterns, surface proteins and capsular types of GBS isolates.

Results

100 of UTI isolates were confirmed as GBS. Antimicrobial susceptibility pattern showed that 95% of GBS isolates were resistant to tetracycline, followed by erythromycin (52%), clindamycin (47%), levofloxacin (9%) and penicillin, cefepime, cefotaxime, and ceftriaxone each with (8%), and vancomycin 1%. Common capsular types were III, Ib, V, II, Ia and IV respectively and the distribution of surface protein genes was as follows: rib (40%), alpha-c (22%), alp2/3 (18%) and epsilon (15%), and alp4 gene was not detected in the isolates. Our findings showed the relationship between capsular types with Alpha-like proteins, as well as reduced sensitivity to antibiotics, so the performance of antibiotic surveillance programs is recommended.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4428-4) contains supplementary material, which is available to authorized users.

Genomic Insights Into the Distribution and Evolution of Group B Streptococcus

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a bacteria with truly protean biology. It infects a variety of hosts, among which the most commonly studied are humans, cattle, and fish. GBS holds a singular position in the history of bacterial genomics, as it was the substrate used to describe one of the first major conceptual advances of comparative genomics, the idea of the pan-genome. In this review, I describe a brief history of GBS and the major contributions of genomics to understanding its genome plasticity and evolution as well as its molecular epidemiology, focusing on the three hosts mentioned above. I also discuss one of the major recent paradigm shifts in our understanding of GBS evolution and disease burden: foodborne GBS can cause invasive infections in humans.

Characterization of group B Streptococcus colonization in full-term and Late-Preterm neonates in Taiwan

BACKGROUND

Group B streptococcus (GBS) infections can be life-threatening in newborns. This study aimed to analyze GBS carriage status and genotypic diversity in healthy neonates after implementation of intrapartum antibiotic prophylaxis (IAP) in Taiwan.

METHODS

Newborns carrying GBS were identified from a screen of 500 newborns and followed up until their cultures turned negative. Their mothers' GBS screening data were reviewed. Molecular methods, including capsular serotyping, multilocus sequence typing and pulsed-field gel electrophoresis (PFGE), were used to analyze GBS isolates.

RESULTS

GBS colonization was detected at either the nose or anus in 11 of 500 healthy neonates (2.2%). In this group of 11 neonates, 4 had GBS serotypes II and III for 4-6 months, 1 had serotype V for 2 months, 6 had serotypes Ia, II, V, and VI for less than 1 month, and 1 had 2 different serotypes (serotypes V and II) at different times. The most prevalent serotype was II (33.3%), followed by Ia (25.0%), III (16.7%), V (16.7%), and VI (8.3%). The main sequence type was ST1 (50.0%), followed by ST19 (16.7%), ST23 (8.3%), ST24 (8.3%), ST103 (8.3%), and ST 231 (8.3%). All isolates were grouped into 5 PFGE clusters F, G, J, X, and Y, and all were susceptible to β-lactam antimicrobial agents.

CONCLUSIONS

GBS was carried in 2.2% (11/500) healthy newborns and persisted for 6 months in 3 neonates. This study makes clearer our understanding of GBS colonization, serotype distribution, and genotype distribution in healthy neonates.

Prevalence of group B streptococcus among pregnant women and newborns at Hawassa University comprehensive specialized hospital, Hawassa, Ethiopia

BACKGROUND

Group B streptococcus (GBS) is reported as the leading cause of neonatal sepsis and meningitis. Newborns from GBS colonized pregnant women are at high risk of infection.

METHOD

A Hospital based cross-sectional study was conducted at Hawassa University Comprehensive Specialized Hospital from November 05, 2014 to March 25, 2015. A total of 280 pregnant women along with their newborns were screened for GBS using standard method recommended by Center of Disease Control and Prevention. GBS strains were serotyped by using serotype specific antisera. A structured questionnaire was used to collect sociodemographic, obstetrics and clinical data of pregnant women and newborns. Data was analyzed by using chi-square and logistic regression to determine factors associated with prevalence of GBS among pregnant women and newborns. Descriptive statistics was used to determine prevalence of GBS among pregnant women and newborns. P value less than 0.05 was considered statistically significant.

RESULT

Prevalence of GBS among pregnant women, newborns and vertical transmission rate at Hawassa University Comprehensive Specialized Hospital were 44(15.7%), 26(8.9%) and 59.1% respectively. Among 26 GBS colonized newborns one developed sign and symptoms of early onset disease. Serotype distribution of GBS isolates collected from pregnant women and newborns was Ia 13(18.6%), Ib 9(12.9%), II 24(34.3%), III 8(11.4%), V 14(20%), and NT 2 (2.9%).

CONCLUSION

In our study we found relatively high prevalence of GBS among pregnant women and vertical transmission rate. The most prevalent GBS serotypes identified in this study were serotype II followed by V, Ia and Ib. Therefore, appropriate prevention strategies such as intrapartum antibiotic prophylaxis and vaccine development should be considered.

The activity of commercial antimicrobials, and essential oils and ethanolic extracts of Olea europaea on Streptococcus agalactiae isolated from pregnant women

BACKGROUND

Streptococcus agalactiae also known as Group B Streptococcus (GBS) is a major cause of disease in pregnant women and new born babies where it causes early and late onset disease characterised by sepsis, pneumonia and meningitis. Ten to 37 % of pregnant women in the world are colonised with GBS while intrapartum antibiotic prophylaxis has led to significant reduction in early onset disease. The increase in drug resistant microorganisms has become a major threat. Development of vaccines is still in progress so there is need for new and safer alternatives to treatment.

METHODS

Benzyl penicillin, Ampicillin, Cefotaxime, Ceftriaxone, Levofloxacin, Erythromycin, Clindamycin, Linezolid, Vancomycin, Tetracycline and Cotrimoxazole, Olea europaea leaf extracts and essential oil were tested against GBS isolates from South Africa and Namibia.

RESULTS

The isolates showed 100% sensitivity to benzyl penicillin, ampicillin, ceftriaxone, levofloxacin, linezolid, vancomycin, O. europaea leaf extracts and essential oils. Only one isolate (0.6%) was resistant to cefotaxime and 23.4 and 10.4% were resistant to clindamycin and erythromycin respectively.

CONCLUSION

GBS isolates showed sensitivity to O. europaea extracts at low minimum inhibitory concentrations. Β lactams are still the drugs of choice for treatment of GBS disease but O. europaea extracts potent as an alternative source of antimicrobials.

Fluoroquinolone-Resistant Streptococcus agalactiae Invasive Isolates Recovered in Argentina

Background: Streptococcus agalactiae or group B Streptococcus (GBS) is an important pathogen in neonates and nonpregnant individuals. Epidemiological studies of GBS resistance to fluoroquinolones (FQs) in Latin America are scarce. This study aimed to determine the local prevalence of FQ resistance in the frame of a national, prospective multicenter study of invasive GBS infections and to investigate mechanisms of resistance, serotype distribution, and clonal relationships among resistant isolates. Methods: From July 2014 to July 2015, 162 invasive GBS isolates were collected from 86 health care centers in 32 Argentinean cities. All isolates were screened for FQ nonsusceptibility using a five-disc scheme: levofloxacin (LVX), ciprofloxacin, norfloxacin (NOR), ofloxacin, and pefloxacin (PF). LVX minimal inhibitory concentration (MIC) was determined by the agar dilution method. Sequencing of internal regions of gyrA and parC genes was performed. Capsular typing and genetic characterization of nonsusceptible isolates were assessed by latex agglutination, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. Results: Twenty-four of one hundred sixty-two GBS isolates exhibited no inhibition zones to all tested FQs with an MIC range of 16-32 mg/L for LVX, and one isolate with MIC = 1 mg/L showed no inhibition zones around NOR and PF discs. In all resistant isolates, point mutations were detected in both genes. Serotype Ib was prevalent (88%). One PFGE type accounted for 84% of the FQ-resistant isolates and belonged to serotype Ib, sequence type 10. Conclusions: The prevalence of FQ resistance was 14.8% likely to be associated with dissemination of an ST10/serotype Ib clone. The unexpected high rate of resistance emphasizes the relevance for continuous surveillance of GBS epidemiology and antibiotic susceptibility.

Prevalence of colonisation by group B streptococcus in pregnant patients in Taguatinga, Federal District, Brazil: a cross-sectional study

PROPOSE

Group B streptococcus is responsible for severe infections in neonates resulting from vertical transmission from pregnant women colonized in the anal, perineal or vaginal regions. The identification of colonized patients and use of intrapartum prophylaxis may reduce the risk of neonatal infection.

METHODS

A cross-sectional study of pregnant women of gestational age between 35 and 37 weeks was conducted. Material was collected from patients for laboratory identification of group B streptococcus. Epidemiological data, including weight, height, body mass index, antibiotic use during pregnancy, pathologies during pregnancy (diabetes, hypertensive diseases, and hypothyroidism), twinning, and others, were also collected from patients.

RESULTS

The sample consisted of 501 pregnant women, and the prevalence of group B streptococcus was 14%. The mean age was 29 years, and the mean BMI was 30.7. During pregnancy, 204 patients had some type of infection, and 201 used antibiotics. Ninety-five patients were diagnosed with gestational diabetes mellitus and 74 with some type of hypertensive disease.

CONCLUSIONS

The prevalence of group B streptococcus observed did not differ from that observed in other studies. None of the factors studied can be considered as risk or protective factors for maternal colonization by group B streptococcus.

Microbiological and clinical characteristics of Group B Streptococcus isolates causing materno-neonatal infections: high prevalence of CC17/PI-1 and PI-2b sublineage in neonatal infections

PURPOSE

Group B Streptococcus (GBS) is one of the major pathogens in severe materno-neonatal infections. We aimed to describe the clinical and molecular characteristics of GBS isolates causing infections in 45 maternal and 50 neonatal subjects, collected from eight healthcare centres in mainland China over the period 2010- 2017.

METHODOLOGY

The phenotypic and genotypic features of the GBS isolates, including capsular polysaccharide (cps) serotypes, pilus island (PI) genes and antibiotic resistance profiles and genes, were characterized by both conventional and molecular methods. The clonal relationship between these strains was investigated using multilocus sequence typing (MLST).

RESULTS

Of the 95 isolates, the predominant serotypes were III (51, 53.7 %), V (13, 13.7 %) and Ib (13, 13.7 %). All GBS strains carried at least one pilus island, with 32.6 % carrying PI-2b and 67.4 % PI-2a, singly or in combination. The most frequently-detected pilus island pattern was the combination of PI-1 and PI-2a, accounting for 56.8 % (54 isolates), followed by PI-1 combined with PI-2b (28, 29.5 %), PI-2a (10, 10.5 %) and PI-2b (3, 3.2 %). The strains were classified into 17 individual sequence types, and further clustered into six clonal complexes (CCs). A high prevalence of CC17/PI-1 and PI-2b (17, 34.0 %) was detected in 50 GBS isolates causing neonatal infections. No strain was resistant to penicillin, ampicillin, ceftriaxone or vancomycin, whereas 78.9, 76.8 and 81.5 % were resistant to erythromycin, clindamycin and tetracycline, respectively.

CONCLUSION

Our study highlights the high genotypic diversity of GBS strains causing materno-neonatal infections, and the CC17/PI-1 and PI-2b sublineages should be noted in neonatal infections.

Perinatal Streptococcus agalactiae Epidemiology and Surveillance Targets

Streptococcus agalactiae, or group B streptococcus (GBS), is a major neonatal pathogen. Recent data have elucidated the global prevalence of maternal and neonatal colonization, but gaps still remain in the epidemiology of this species. A number of phenotypic and genotypic classifications can be used to identify the diversity of GBS strains, and some are more discriminatory than others. This review explores the main schemes used for GBS epidemiology and further details the targets for epidemiological surveillance. Current screening practices across the world provide a unique opportunity to gain detailed information on maternal colonizing strains and neonatal disease-causing strains, which is vital for monitoring and therapeutics, if sufficient detail can be extracted. Deciphering which isolates are circulating within specific populations and recording targets within invasive strains are crucial steps in monitoring the implementation of therapeutics, such as vaccines, as well as developing novel therapies against prevalent GBS strains. Having a detailed understanding of global GBS epidemiology will prove invaluable for understanding the pathogenesis of this organism and equipping future prevention strategies for success.

Progress toward a group B streptococcal vaccine

Streptococcus agalactiae (group B Streptococcus, GBS) is a leading cause of severe invasive disease in neonate, elderly, and immunocompromised patients worldwide. Despite recent advances in the diagnosis and intrapartum antibiotic prophylaxis (IAP) of GBS infections, it remains one of the most common causes of neonatal morbidity and mortality, causing serious infections. Furthermore, recent studies reported an increasing number of GBS infections in pregnant women and elderly. Although IAP is effective, it has several limitations, including increasing antimicrobial resistance and late GBS infection after negative antenatal screening. Maternal immunization is the most promising and effective countermeasure against GBS infection in neonates. However, no vaccine is available to date, but two types of vaccines, protein subunit and capsular polysaccharide conjugate vaccines, were investigated in clinical trials. Here, we provide an overview of the GBS vaccine development status and recent advances in the development of immunoassays to evaluate the GBS vaccine clinical efficacy.

Characterization of group B Streptococcus isolated from sterile and non-sterile specimens in China

Group B streptococcus (GBS) is a leading cause of invasive neonatal infections and has increasingly been associated with invasive diseases in non-pregnant adults. We collected 113 GBS isolates recovered from sterile and non-sterile specimens from seven tertiary hospitals in China between October 2014 and September 2016. Medical records were retrospectively reviewed and the sequence types, serotypes, virulence, and antimicrobial resistance profiles of the isolates were characterized and correlated. Significantly higher C-reactive protein and procalcitonin levels and absolute neutrophil counts were observed in patients with invasive infections than in those with non-invasive infections (P < 0.05). The 113 isolates were grouped into 24 sequence types, 5 clonal complexes, and 6 serotypes. multivariate analysis revealed that clonal complex 17 isolates characterized by serotype iii, the surface protein gene rib, and the pilus island pi-2b were independently correlated with invasive infection (or: 6.79; 95% ci: 2.31-19.94, P < 0.001). These results suggest alternative molecular biomarkers for diagnosis and prognosis of GBS infections.

Streptococcus agalactiae carriage among pregnant women living in Rio de Janeiro, Brazil, over a period of eight years

Group B Streptococcus (GBS) carriage by pregnant women is the primary risk factor for early-onset GBS neonatal sepsis. Intrapartum antibiotic prophylaxis (IAP) can prevent this transmission route, and two main approaches are recommended to base the selection of pregnant women to be submitted to IAP: the risk-based and the culture-based strategies. In Brazil, compliance to such recommendations is poor, and not much is known about GBS carriage. In the present study, 3,647 pregnant women living in Rio de Janeiro State, Brazil, were screened for GBS anogenital colonization, over a period of 8 years (2008–2015). GBS was detected in 956 (26.2%) of them, and presence of vaginal discharge was the only trait associated with a higher risk for GBS colonization. Serotypes Ia (257; 37.3%) and II (137; 19.9%) were the most frequent among 689 (72.1% of the total) GBS isolates evaluated, followed by NT isolates (84; 12.1%), serotype Ib (77; 11.1%), V (63; 9.1%), III (47; 6.8%) and IV (24; 3.5%). Estimated coverage of major serotype-based GBS vaccines currently under clinical trials would vary from 65.2% to 84.3%. All 689 isolates tested were susceptible to ampicillin and vancomycin. Resistance to chloramphenicol, clindamycin, erythromycin, levofloxacin, and tetracycline was observed in 5% (35), 2% (14), 14% (97), 5% (35) and 86% (592) of the isolates, respectively. No significant fluctuations in colonization rates, serotype distribution and antimicrobial susceptibility profiles were observed throughout the period of time investigated. The culture-based approach for IAP recommendation showed to be the best choice for the population investigated when compared to the risk-based, since the first did not increase the number of pregnant women submitted to antibiotic therapy and covered a larger number of women who were actually colonized by GBS. The fact the not all isolates were available for additional characterization, and serotype IX antiserum was not available for testing represent limitations of this study. Nevertheless, to the best of our knowledge, this is the largest investigation on GBS carriage among pregnant women in Brazil up to date, and results are useful for improving GBS prevention and treatment strategies.

Neonatal colonization of group B Streptococcus in China: Prevalence, antimicrobial resistance, serotypes, and molecular characterization

BACKGROUND

Group B Streptococcus (GBS) remains a leading cause of neonatal mortality and morbidity. This study aimed to determine the prevalence, antimicrobial susceptibility, serotypes, and molecular characterization of GBS colonized in neonates.

METHODS

A cross-sectional study was conducted using a multistage sampling method. Swabs for GBS identification were taken from infants' ear, oral cavity, and umbilicus immediately after birth. All GBS isolates were tested for antimicrobial susceptibility, resistance genes, serotyping, multilocus sequence typing, and virulence genes.

RESULTS

Of the 1,814 neonates, 1.3% tested positive for GBS, with 66.7% tested as multidrug resistant. All GBS isolates were susceptible to penicillin, but rates of resistance to tetracycline and erythromycin were high (70.8%), with the predominant resistance genes being tetM and ermB. The predominant serotype was III, followed by Ia and Ib, and the most common genotypes were sequence type (ST) 19, ST10, and ST485. Notably, we found that ST19 and ST17 isolates were associated with serotype III, resistant to tetracycline, erythromycin, and clindamycin, and carrying ermB, tetM, and rib; ST10 and ST12 isolates were associated with serotype Ib, resistant to erythromycin and clindamycin, and carrying ermB and alphaC; and ST485 isolates were associated with serotype Ia and carrying mefA/E, tetM, and epsilon.

CONCLUSIONS

These findings indicate a high prevalence of multidrug-resistant GBS and specific phenotype-genotype combinations for GBS clones.

Serotype distribution and clinical correlation of Streptococcus agalactiae causing invasive disease in infants and children in Taiwan

BACKGROUND

Streptococcus agalactiae, or group B Streptococcus (GBS), remains to be one of the leading pathogens causing invasive infections in infants.

METHODS

The clinical GBS isolates from sterile sites of patients younger than 18 years old were collected from October 1998 to December 2014 in two hospitals in Taiwan. Medical records were retrospectively reviewed. Every isolate was serotyped with a multiplex PCR assay. Multilocus sequence typing (MLST) was performed in representative isolates of different serotypes. A total of 205 GBS isolates were collected from 181 patients with 182 infection episodes.

RESULTS

Serotype Ia was the most common in patients less than 72 h old, whereas III the most common in patients older than 72 h. In early-onset disease (0-6 days), Ia and III each caused 27.5% of the infection, followed by Ib (14.5%). In late-onset disease (7-89 days), serotype III predominated (75.3%), followed by Ia (10.1%) and Ib (6.8%). Thirty-one episodes (17%) were complicated with culture-confirmed meningitis. We compared serotype Ia and III patients, and found that serotype Ia patients were significantly younger (median age, 3 days), had more perinatal maternal fever and higher mortality. ST17 and ST19 were exclusively found in serotype III, while ST23 and ST24 comprised of 85% of serotype Ia.

CONCLUSION

In Taiwan, serotypes Ia and III are the most common cause for early-onset and late-onset neonatal GBS infections, respectively. Some differences in the clinical features of invasive GBS infections caused by serotype Ia and III were observed.

Serotype, virulence profile, antimicrobial resistance and macrolide-resistance determinants in Streptococcus agalactiae isolates in pregnant women and neonates in Catalonia, Spain

INTRODUCTION

Streptococcus agalactiae, or group B streptococci (GBS), is the main aetiological agent of early neonatal sepsis in developed countries. This microorganism belongs to the gastrointestinal tract microbiota wherefrom it can colonize the vagina and be vertically transmitted to the child either before or at birth, and subsequently cause infection in the newborn. Approximately, 50% of newborns born to women with GBS become colonized, with 1-2% developing early neonatal infection if no preventive intervention is performed. The aim of this study was to characterize and compare serotypes, virulence factors and antimicrobial resistance of GBS isolates collected from pregnant women and newborns in several hospitals in Catalonia.

METHODS

242 GBS strains were analyzed including 95 colonizers and 68 pathogenic strains isolated from pregnant women, and 79 strains isolated from neonates with sepsis in order to determine serotype, virulence and antimicrobial resistance.

RESULTS

Serotype distribution was different among the three groups, with serotypes Ia and II being significantly more frequent among colonizing strains (p=0.001 and 0.012, respectively). Virulence factors bca and scpB were significantly more frequent among neonatal strains than pathogenic or colonizing strains (p=0.0001 and 0.002, respectively). Pathogenic strains were significantly more resistant to erythromycin, clindamycin and azithromycin than their non-pathogenic counterparts.

CONCLUSIONS

Taking into account that neonatal sepsis represents a significant problem on a global scale, epidemiological surveillance, antimicrobial resistance and GBS virulence at the local level could provide important knowledge about these microorganisms as well as help to improve treatment and prevent invasive infection caused by this microorganism.