A study of the prevalence of group B streptococci in the third trimester of pregnancy

Background: Group B Streptococci (GBS) is an important cause of early onset neonatal sepsis and the maternal colonization of this organism is a key factor in the occurrence of GBS associated morbidity and mortality in the newborns. Timely recognition of its presence in the genital tract of a pregnant women and intrapartum antibiotic prophylaxis can significantly bring down the burden of the disease in neonates. A cross sectional study was conducted on  antenatal women during 35-37weeks of gestation to evaluate the prevalence of Group B Streptococci in third trimester of pregnancy and explore the feasibility of including GBS screening in the routine antenatal investigation protocol.Methods: 200 antenatal women satisfying the exclusion/inclusion criteria were recruited for the study. Vaginal and perianal swabs were collected using sterile swab sticks and inoculated using the specified media. Beta hemolysis and typical colonies were looked for under microscope. Positive cases were subjected to intrapartum antibiotic prophylaxis and the neonates were observed for 72 hours to look for any signs of sepsis.Results: It was found that 2% of the women screened were positive for GBS .While none of the newborns of the 4 positive cases showed any signs of sepsis.Conclusions: Prophylactic intrapartum prophylaxis against GBS has shown to decrease the chances of neonatal sepsis but more detailed and robust studies are required before incorporating routine screening in our antenatal care system.

Antibiotic susceptibility pattern of group B streptococcal isolates from maternal genital tract

Background: Group B streptococcus (GBS) is one of the important cause of early onset neonatal sepsis in developed countries leading to increased neonatal morbidity and mortality. Penicillin and Ampicillin are the drugs of choice for prevention of GBS infections. Antibiotic resistance amongst GBS isolates is an emerging health problem affecting neonates. Hence, this study was performed to determine the antibiotic susceptibility pattern of Group B Streptococcus (GBS) in a population of pregnant women.Methods: A prospective study was done to screen pregnant women for vaginal and rectal GBS colonization during their regular visits to antenatal clinic. Todd-Hewitt broth, an enrichment medium for GBS was used for isolation. The antibiotic susceptibility pattern of the isolates were studied.  Results: A total of 300 pregnant women were screened for GBS colonization. GBS colonization rate in our study was 2.3%. The antibiotic susceptibility pattern of the isolates revealed that none of the isolates were resistant to penicillin or clindamycin, while resistance was noted to erythromycin (14.3%) and   tetracycline (71.4%).Conclusions: GBS continues to remain sensitive to Penicillin which is the drug of choice for prevention and treatment of GBS.  Consistent surveillance of antibiotic sensitivity pattern of GBS as well as for other organisms implicated in new born sepsis and maternal infections is required to formulate guidelines for prevention and treatment.

Suscetibilidade antimicrobiana de Streptococcus agalactiae isolados de gestantes em um hospital materno infantil de Porto Alegre, Rio Grande do Sul / Antimicrobial susceptibility of Streptococcus agalactiae isolated from pregnant women at a maternity hospital in Porto Alegre, Rio Grande do Sul, Brazil

OBJETIVOS: Caracterizar o perfil de suscetibilidade antimicrobiana de Streptococcus agalactiae isolados de gestantes atendidas em um hospital público. MÉTODOS: O estudo foi realizado em um hospital materno-infantil público de Porto Alegre, RS, no qual a pesquisa de S. agalactiae em gestantes faz parte da rotina obstétrica. Foram incluídas no estudo as pesquisas por swab anal/vaginal realizadas no período de julho de 2015 a fevereiro de 2016. Os isolados bacterianos foram identificados por testes fenotípicos e foi determinada a suscetibilidade aos antimicrobianos ampicilina, clindamicina, eritromicina e ofloxacino. Foram investigados também os genes de resistência à eritromicina ermB e mefA. RESULTADOS: No total, 294 coletas foram incluídas e destas, 26 (8%) foram positivas para S. agalactiae. Todos os isolados avaliados foram sensíveis à ampicilina e foram observadas resistências à eritromicina (21,4%), clindamicina (14,3%) e ofloxacino (7,1%), sendo que 66% dos isolados resistentes à eritromicina apresentaram o genótipo mefA. CONCLUSÕES: Os resultados deste estudo corroboram com o consenso de que em gestantes colonizadas com S. agalactiae é aconselhada a antibioticoprofilaxia intraparto com penicilina G ou ampicilina. A expressiva proporção de isolados resistentes à eritromicina e clindamicina, indicados para a antibioticoprofilaxia intraparto em caso de alergia aos antibióticos beta-lactâmicos, enfatiza a importância da determinação do perfil de suscetibilidade antimicrobiana prévia desses isolados, medida que ainda não faz parte da rotina de exames pré-natais em muitas instituições.

AIMS: To characterize the antimicrobial susceptibility profile of Streptococcus agalactiae isolated from pregnant women attended at a public hospital. METHODS: The study was carried out in a public maternal and child hospital in Porto Alegre, RS, Brazil, in which the screening for S. agalactiae in pregnant women is part of the obstetrics routine. The study was carried out on anal/vaginal swab tests performed from July 2015 to February 2016. Bacterial isolates were identified by phenotypic tests, and the susceptibility to ampicillin, clindamycin, erythromycin and ofloxacin was determined. The erythromycin resistance genes ermB and mefA were also investigated. RESULTS: A total of 294 samples were included, and of these, 26 (8%) were positive for S. agalactiae. All isolates were susceptible to ampicillin, and resistance to erythromycin (21.4%), clindamycin (14.3%) and ofloxacin (7.1%) were observed. The mefA genotype was observed in 66% of the erythromycin resistant isolates. CONCLUSIONS: Results of this study corroborate the consensus that in pregnant women colonized with S. agalactiae, intrapartum antibiotic prophylaxis with penicillin G or ampicillin is indicated. The relevant proportion of isolates resistant to erythromycin and clindamycin, indicated for intrapartum antibiotic prophylaxis in case of allergy to beta-lactam antibiotics, emphasizes the importance of determining the profile of antimicrobial susceptibility of these isolates, a measure that is not yet part of routine prenatal tests in many institutions.

Analysis of Serological Distribution,Virulence Gene and Drug Resistance among Group B Streptococcus from Shenzhen Patients / 现代检验医学杂志

Objective To understand the antimicrobial susceptibility profiles,serotype distribution and virulence genes.Methods A total of 515 group B Streptococcus (GBS) including 108 virulence,112 non virulence,and 295 colonizing isolates were collected in four Shenzhen hospitals.Isolates were characterized by conventional and molecular serotyping.The virulence genes of scpB,lmb,hylB,cylE,bac,bca and rib of GBS isolates were detected by PCR.Antimicrobial susceptibility to penicillins,macrolides,lincosamides,quinolones and tetracyclines was tested using disk diffusion and the MICs for penicillin were determined by E test.Results Molecular serotyping for all eight serotypes (Ⅰa,Ⅰb,Ⅱ ～ Ⅵ,Ⅸ) was in full accordance with conventional serotyping.Taking MS and CS together,serotype Ⅲ was the most common capsular type (56.5 ％),followed by Ⅰb (17.5 ％),Ⅰa (12.6 ％),V (7.4 ％),Ⅱ (2.7 ％),Ⅵ (1.4 ％),Ⅳ (1.0 ％) and Ⅸ (1.0 ％).Serotype Ⅲ was the main serotype in different groups,serotype Ⅰ a was significantly more common among patients with invasive infections (11.1％) and no invasive infections (29.5％),serotype Ⅰb isolates were significantly more common among clone (19.3％).Virulence gene screening using PCR method showed the presence of cylE,lmb,scpB and hylB in almost all the isolates,while rib,bca and bac genes were found in 29.1％,14.6％ and 9.7％ of the isolates.Certain genes were significantly associated with specific serotypes,for example,rib with serotypes Ⅲ,Ⅰa and Ⅰb,bca and bac with serotypes Ⅲ and Ⅰb.Drug susceptibility results showed that GBS susceptibility to β lactam antimicrobials was prevalent (100 ％).Resistance rates for erythromycin,clindamycin and tetracycline were 67.0 ％,61.9 ％ and 86.0 ％,respectively.Conclusion Serotype distribution,virulence genes and antimicrobial susceptibility profiles of GBS contributes to the clinical therapy,epidemiological studies and design of Vaccines.

Group B Streptococcus Infection in Vaginal Tract of Perinatal Pregnant Women and Drug Resistance Analysis / 现代检验医学杂志

Objective To provide evidences which are for clinicians to formulate effective prevention and treatment measures by analyzing the perinatal pregnant women vaginal group B streptococcus (GBS)infection and adverse pregnancy outcomes. Methods From January 2013 to February 2015,the vaginal secretions were sampled from 795 cases of perinatal pregnant women for culture identification of GBS,the final results were statistical analyzed.Results In the 795 pregnant women ca-ses,there were 256 GBS carriers cases,the carrier rate was 32.2%.There was statistically significance (χ2 = 19.095,P <0.01)between less than 30 years old group (28.9%)and greater than or equal to 30 years old group (42.3%).The differ-ent incidence rate of clinical symptoms between GBS negative cases and GBS positive cases (18.8% vs 8.0%)was also had statistically significance (χ2 =39.514,P <0.01).The antimicrobial resistant rates of ten kinds of antibacterial drugs (vanco-mycin,linezolid,penicillin,ampicillin,ceftriaxone,nitrofurantoin,levofloxacin,clindamycin,erythromycin and tetracycline) was 0,0,0.6%,3.1%,6.6%,9.6%,21.9%,23.8%,29.9% and 58.1% respectively.The positive rate of D-bacteriostatic ring experiment was 23.9%.Conclusion The carrier rate of perinatal pregnant women GBS was higher in this region,and the elderly were easier to be infected.Perinatal pregnant women infected with GBS to vancomycin and rina thiazole amine and penicillin and ampicillin and ceftriaxone and with nitrofurantoin because of the sensitive rate is high.

Effects of different group B streptococci strains on platelet activation / 中国病理生理杂志

AIM:To explore the ability of different group B streptococci ( GBS) strains on inducing platelet activation.METHODS:Six strains of GBS, separated from the septic patients with thrombocytopenia, were used as the inducers.Light transmission aggregometry was used to measure platelet aggregation.Scanning electron microscopy ( SEM) was performed to investigate the interaction of platelets with bacteria.The expression of platelet CD62P, Toll-like receptor 2 ( TLR2) and TLR4 was determined by flow cytometry and Western blotting.Furthermore, the activity of platelet TLR2 (or TLR4) was blocked by anti-TLR2 (or anti-TLR4) monoclonal antibody, and the platelet aggregation induced by GBS was detected.RESULTS:Only 3 of 6 GBS strains isolated from the septic patients induced platelet aggregation and up-regulated the expression of CD62P and TLR2 in the platelets (P<0.05), but not TLR4.Incubation with anti-TLR2 anti-body, but not anti-TLR4 antibody, significantly blocked platelet aggregation induced by GBS.CONCLUSION:Some GBS strains from the patients are able to trigger platelet activation in vitro, and platelet TLR2 may play an important role in the interaction between GBS and platelets.

Clinical Application of Novel Colloidal Gold Immunochromatographic Test Strip for Group B Streptococci / 现代检验医学杂志

Objective To explore the effect of a novel colloidal gold immunochromatographic test strip for detection of group B streptococci (GBS).Methods A total of 202 cases of swab of vagina or neck of uterus were collected,and they were detec-ted by novel strip and control strip to evaluate their clinical applications.Results Sensitivity of novel strip was about 105 CFU/ml and the detection time was about 5 to 8 minutes,and it showed better sensitivity and shorter detection time com-pared with control strip.In the 202 cases of clinical samples,the detection results of 197 cases were in consistent with the control strip,however,the detection results of 5 cases were not in consistent.The positive coincidence rate and negative coin-cidence rate were 97.5% and 97.54% respectively,and the total coincidence rate and Kappa value were 97.52% and 0.948 respectively.The consistency test showed no significant difference between this strip and control strip.Conclusion This method was a effective technology for diagnosing of infection caused by GBS,and had high value in clinical application.

Clinical Characteristics of Streptococcus agalactiae Bacteremia in Adults Living in Jeju Island / 대한임상미생물학회지

BACKGROUND: Streptococcus agalactiae (Group B streptococcus, GBS) is known to be the leading cause of neonatal sepsis and meningitis in the United States and Europe. In addition, GBS infection has been increasingly noted in adults, particularly in those with underlying diseases, such as diabetes mellitus, malignancy and liver disease. A few studies reported that resistances to antibiotics, such as erythromycin, clindamycin, tetracycline are increasing. We report clinical and microbiological characteristics of GBS bacteremic patients in Jeju Island. METHODS: We retrospectively analyzed medical records, such as age, sex, underlying disease, mortality, skin defects, laboratory results and antibiotic resistances of GBS in hospitalized adult patients who were diagnosed with GBS bacteremia from 2008 to 2013 in Jeju Island. RESULTS: Twenty two adult patients were diagnosed as GBS bacteremia from 2008 to 2013. The mean age of GBS bacteremic patients was 66.2 years old. Of 22 bacteremic patients, fifteen patients (68%) were older than 60. Twenty patients (91%) of bacteremic patients had underlying diseases such as diabetes mellitus, malignancy and liver disease. Ten (45%) patients had skin defects which were on the lower extremities and buttock, fifteen (68%) patients had fever at the time of admission, twenty one (95%) patients were admitted via the emergency department. Two (9%) patients died. The mean white blood cell (WBC) count, percentile of neutrophil count, and C-reactive protein (CRP) levels were 11,488/microL, 84.3 %, 13.5 mg/dL respectively. All GBS isolates from bacteremia showed sensitivities to penicillin, ampicillin, and vancomycin, and showed resistances to erythromycin (25%), clindamycin (30%), and tetracycline (55%). CONCLUSION: Bacteremia caused by GBS was prevalent in adult patients with underlying diseases. Most of the GBS bacteremic patients were emergency cases, with a high body temperature, WBC, CRP level, and neutrophil count. Half of them had skin defects, which are considered a source of GBS bacteremia.

Group B Streptococcal Disease in Korean Neonates / 소아감염

Group B streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis in developed countries. This article reviews the neonatal invasive GBS disease, maternal GBS colonization, and prevention strategies in the context of recent epidemiological changes in Korea. Although Korean neonates had been supposed to have low incidence of invasive GBS disease, GBS has been recently reported to be the most common cause of invasive neonatal infection after 1990s. Among Korean pregnant women, GBS carriage rate in the vagina and rectum has been reported to be much lower than that in Western countries. However, it has increased in recent studies. For decision making about preventive strategy for neonatal GBS disease in Korea, further studies are required in terms of the incidence of neonatal GBS infection and serotype distribution. In addition, studies about maternal carriage rate and serotype distribution have to be continued.

Enfermedad neonatal temprana por Streptococcus agalactiae en una unidad de recién nacidos, factores de riesgo materno-fetales asociados a severidad y mortalidad / Streptococcus agalactiae early neonatal disease in a nursery, neonatal and maternal risk factors associated with severity and mortality / No início da doença neonatal causada pelo Streptococcus agalactiae em um viveiro, os fatores de risco materno-fetal associados com a gravidade e mortalidade

La colonización materna por estreptococo del grupo B (SGB) en países en desarrollo es del 4-20%; el 50% de sus hijos nacen colonizados y el 1-2% desarrollan enfermedad invasiva con alto riesgo de morbimortalidad y secuelas. Objetivo: determinar los factores de riesgo materno-fetales asociados a enfermedad severa y mortalidad neonatal por SGB en una unidad de recién nacidos. Materiales y métodos: se realizó un estudio observacional analítico de cohorte histórica durante un período de dos años. Se tomaron 11 casos con enfermedad invasiva y 15 controles. Se calcularon frecuencias absolutas y relativas, y se buscaron asociaciones mediante el cálculo del estadístico chi². Resultados: los factores maternos predictivos para enfermedad por SGB incluyeron fiebre periparto mayor a 37,5 grados centígrados (p < 0,05), corioamnionitis y ruptura de membranas mayor a 18 horas (p < 0,05). Los factores de riesgo neonatal incluyeron prematurez (< 37 semanas) y bajo peso al nacer (< 2.500 gramos) (p < 0,05). Se encontró una mortalidad de 5 (45%). Conclusiones: hubo relación estadísticamente significativa entre la corioaminionitis materna, la ruptura de membranas mayor a 18 horas, la prematurez y el peso bajo al nacer con la severidad de la enfermedad y la mortalidad. La incidencia estimada de infección neonatal en la unidad de recién nacidos fue de 1,8 casos/1.000 nacidos vivos, y la de colonización materna fue de 4,3 casos/1.000 maternas. Se deben realizar más estudios en el país para establecer la incidencia real de enfermedad neonatal por SGB y hacer investigación sobre la costo-efectividad de las medidas de prevención.

Maternal colonization of group B Streptococcus (GBS) in developing countries is 4-20%, 50% of their children born colonized and 1-2% develop invasive disease at high risk of mortality and sequelae. Objective: determine maternal-fetal risk factors associated with severe disease and mortality of GBS in a neonatal nursery. Materials and methods: an observational study of historical cohort during a period of 2 years. It took eleven cases with invasive disease and fifteen controls. We calculated absolute and relative frequencies and associations were sought by calculating the statistic chi². Results: The predictive maternal factors included GBS disease, peripartum fever greater than 37.5 degrees Celsius (p < 0.05), chorioamnionitis and rupture of membranes more than 18 hours (p < 0.05). Neonatal risk factors included prematurity (< 37 weeks) and low birth weight (< 2500 grams) (p < 0.05). We found a mortality of 5 (45%). Conclusions: There was a statistically significant relationship between maternal chorioamnionitis, rupture of membranes more than 18 hours, prematurity and low birth weight with disease severity and mortality. The estimated incidence of neonatal infection in the nursery was 1.8 per 1000 live births and maternal colonization was 4.3 cases per 1000 maternal. Further studies should be conducted in the country to establish the true incidence of neonatal GBS disease and do research on cost-effectiveness of preventive measures.

A colonização materna por estreptococo do grupo B (SGB) em países em desenvolvimento é de 4-20%, 50% de seus filhos nascem e o 1-2% desenvolvem doença invasiva com alto risco de morbimortalidade e seqüelas. Objetivo: determinar os fatores de risco materno-fetais associados à doença severa e mortalidade neonatal por SGB em uma unidade de recém-nascidos. Materiais e Métodos: realizou-se um estudo observacional analítico coorte histórica durante um período de 2 anos. Tomaram-se onze casos com doença invasiva e quinze controles. Calcularam-se freqüências absolutas e relativas e se procuraram associações mediante o cálculo do estadístico Chi². Resultados: os fatores maternos preditivos para doença por SGB incluíram, febre periparto maior a 37,5 graus centígrados (p <0.05), corioamnionite e rotura de membranas maior a 18 horas (p<0.05). Os fatores de risco neonatal incluíram prematuridade (<37 semanas) e baixo peso ao nascer (<2500 gramas) (p<0.05). Encontrou-se uma mortalidade de 5(45%). Conclusões: houve relação estadisticamente significativa entre a corioamnionite materna, a rotura de membranas maior a 18 horas, a prematuridade e o baixo peso ao nascer com a severidade da doença e a mortalidade. A incidência estimada de infecção neonatal na unidade de recém-nascidos foi de 1,8 casos/1000 nascidos vivos e a clonização materna foi de 4,3 casos/1000 maternas. Devem-se realizar mais estudos no país para estabelecer a incidência real de doença neonatal por SGB e fazer pesquisa sobre a custo-efetividade das medidas de prevenção.

Papel de metaloproteases de Estreptococos do grupo B na interação, viabilidade celular e indução de apoptose e necrose em células endoteliais e epiteliais humanas / Role of metalloproteinases of Group B Streptococci in the interaction, cell viability and induction of apoptosis and necrosis in human epithelial and endothelial cells

Estreptococos do grupo B (EGB) é a principal causa de sepse e meningite neonatal e tem sido recentemente reconhecido como patógeno responsável por infecções invasivas em adultos imunocomprometidos (idosos ou portadores de doenças crônicas). Os EGB produzem inúmeras enzimas extracelulares, várias das quais interagem com o sistema imune do hospedeiro e são importantes durante a interação EGB-hospedeiro, bem como para o desenvolvimento da doença. Estudos anteriores mostraram que metaloproteases estão envolvidas em várias vias metabólicas em diferentes tipos celulares. Por esta razão, nós decidimos investigar o possível envolvimento de metaloproteases de EGB durante a interação celular e apoptose/necrose induzida pelo micro-organismo em células endoteliais da veia umbilical humana (HUVEC) e da linhagem de epitélio respiratório (A549). Tratamento de EGB com inibidores de metaloproteases (EDTA, EGTA e FEN) não induziu alterações no crescimento bacteriano, mas promoveu alterações na expressão de proteínas de superfície, capacidade adesiva e perfil de sobrevivência intracelular do patógeno. O EGB e o sobrenadante do crescimento bacteriano (meio condicionado; MC) promoveram a morte das células HUVEC e A549. Contudo, o tratamento com inibidores de metaloproteases restauraram a viabilidade celular induzida pelos EGB e o MC, sugerindo que metaloproteases bacteriana estão envolvidas no rompimento da barreira celular, promovendo a disseminação bacteriana. Este trabalho descreve pela primeira vez apoptose e necrose induzidas pelo EGB e MC em HUVEC e células A549 após 24h de incubação, respectivamente. Nós também observamos redução da pró-caspase-3 após infecção das HUVEC com EGB e MC, sugerindo ativação da caspase-3. Além disso, o aumento da expressão da proteína pró-apoptótica Bax e diminuição dos níveis da proteína anti-apoptótica Bcl-2 em HUVEC, demonstram o envolvimento do mecanismo apoptótico mitocondrial (via intrínseca). A melhor compreensão das bases molecular...

Group B streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis and has recently been recognized as an increasingly common cause of invasive disease in immunocompromised adults (elderly or chronic diseases). GBS produces a number of extracellular enzymes, several of which interact with the host immune system and are important for the GBS- host interaction and for the development of disease. Previous studies showed that metalloproteases are involved in several metabolic pathways in different cellular types. For this reason, we decided to investigate the possible involvement of GBS metalloproteases during cell interaction and apoptosis/necrosis induced by microorganism in human umbilical vein endothelial cells (HUVEC) and epithelial respiratory cells line (A549). Treatment of GBS with metalloproteases inhibitors (EDTA, EGTA and PHEN) did not induce alteration on bacterial growth, but promoted changes in the expression of surface proteins, adhesive capacity and profile of intracellular survival of the pathogen. The GBS and supernatant of bacterial growth medium (conditioned medium; MC) promoted the death of HUVEC and A549 cells. However, the metalloproteases inhibitors treatment restored the cellular viability induced by GBS and MC, suggesting that GBS metalloproteases are involved in the disruption of cell barrier, promoting bacterial dissemination. This study describes for the first time apoptosis and necrosis induced by GBS and MC in HUVEC and A549 cells after 24h incubation, respectively. We also observe reduction of pro-caspase-3 after infection of HUVEC with GBS and MC, suggesting activation of caspase-3. Moreover, the over-expression of pro -apoptotic protein Bax and decrease of anti-apoptotic protein Bcl-2 levels in HUVEC show the involvement of mitochondrial apoptotic mechanism (intrinsic via). Enhanced understanding of the molecular basis of GBS pathogenesis may pinpoint novel bacterial and host molecules that can represent novel...

Detection of Group B Streptococcus in Brazilian pregnant women and antimicrobial susceptibility patterns

Group B Streptococcus (GBS) is still not routinely screened during pregnancy in Brazil, being prophylaxis and empirical treatment based on identification of risk groups. This study aimed to investigate GBS prevalence in Brazilian pregnant women by culture or polymerase chain reaction (PCR) associated to the enrichment culture, and to determine the antimicrobial susceptibility patterns of isolated bacteria, so as to support public health policies and empirical prophylaxis. After an epidemiological survey, vaginal and anorectal specimens were collected from 221 consenting laboring women. Each sample was submitted to enrichment culture and sheep blood agar was used to isolate suggestive GBS. Alternatively, specific PCR was performed from enrichment cultures. Antimicrobial susceptibility patterns were determined for isolated bacteria by agar diffusion method. No risk groups were identified. Considering the culture-based methodology, GBS was detected in 9.5 percent of the donors. Twenty five bacterial strains were isolated and identified. Through the culture-PCR methodology, GBS was detected in 32.6 percent specimens. Bacterial resistance was not detected against ampicillin, cephazolin, vancomycin and ciprofloxacin, whereas 22.7 percent were resistant to erythromycin and 50 percent were resistant to clindamycin. GBS detection may be improved by the association of PCR and enrichment culture. Considering that colony selection in agar plates may be laboring and technician-dependent, it may not reflect the real prevalence of streptococci. As in Brazil prevention strategies to reduce the GBS associated diseases have not been adopted, prospective studies are needed to anchor public health policies especially considering the regional GBS antimicrobial susceptibility patterns.

Pulsed-field gel electrophoresis, virulence determinants and antimicrobial susceptibility profiles of type Ia group B streptococci isolated from humans in Brazil

Group B streptococci (GBS) infections occur worldwide. Although serotyping has been used for epidemiologic purposes, this does not accurately characterize enough members of a genetically heterogeneous bacterial population. The aims of this work were to evaluate the genetic diversity of 45 type Ia GBS strains isolated in Brazil by pulsed-field gel electrophoresis as well as to evaluate antimicrobial susceptibility profiles and identify virulence genes. Twenty-four strains were assigned to cluster A. All strains under study contained the hylB and scpB genes. The bca gene was detected in only 10 strains and none of the streptococci carried the bac gene. Thirty-nine strains were resistant to tetracycline.

Colonization Rate, Serotypes, and Distributions of Macrolide-Lincosamide-Streptogramin(B) Resistant Types of Group B Streptococci in Pregnant Women / 대한임상미생물학회지

BACKGROUND: The prevalence of neonatal group B streptococcal infection depends mainly on the colonization rate of pregnant women by group B streptococci (GBS). Although the colonization rate of Korean women by GBS is considered lower than in other countries, recent data on the maternal colonization rate of GBS are sparse. METHODS: From August 2008 to June 2009, swab specimens from the anorectus, vagina, and urethral orifice of a sample of 234 pregnant Korean women were placed in new Granada medium (NGM-H), tube medium (NGM-T), commercial NGM (NGM-B), and selective Todd-Hewitt broth (S-THB) for 18~24 hours in 5% CO2 at 35degrees C. Agar dilutional antimicrobial susceptibility tests, serotyping, and PCR were performed for GBS isolates. RESULTS: The colonization rate of GBS in pregnant women was 11.5% (27/234). Of the specimen cultures, 9.8% of anorectal cultures were positive, 8.1% of urethral orifice cultures were positive, and 7.3% of vagina cultures were positive. The detection rate of GBS in the different culture media was S-THB (96.3%), NGM-B (92.6%), NGM-H (88.9%), and NGM-T (85.2%). The distribution of GBS serotypes was as follows: III (29.6%), V and VI (22.2%), Ib and II (11.1%), and Ia (3.7%). 33.3% of GBS isolates were resistant to erythromycin and 44.4% to clindamycin. Among the nine erythromycin-resistant isolates, eight were serotype V and VI, which are erm(B) positive serotypes. CONCLUSION: The colonization of pregnant women by GBS, and the incidence of resistance of the GBS isolates to erythromycin and clindamycin were higher than those previously reported. Serotypes V and VI, GBS serotypes that carry the erm(B), are novel serotypes that have not previously been identified in pregnant Korean women.

Correlation of Serotypes and Genotypes of Macrolide-Resistant Streptococcus agalactiae

Despite the necessity for studies of group B streptococci (GBS), due to the increase in serious adult infections, the emergence of new serotypes, and the increased resistance to macrolide antibiotics, such studies have been limited in Korea. The primary purpose of the present study was to determine the frequency trends of GBS serotypes, including serotypes VI, VII, and VIII. The final objective was to elucidate the relationship between the genotypes and serotypes of macrolide-resistant GBS isolates from a Korean population. Among 446 isolates of Streptococcus agalactiae, isolated between January 1990 and December 2002 in Korea, the frequency of serotypes were III (36.5%), Ib (22.0%), V (21.1%), Ia (9.6%), VI (4.3%), II (1.8%), VIII (1.3%), IV (1.1%), and VII (0.9%). The resistance rates to erythromycin, by serotype, were 85% (V), 23% (III), 21% (VI), 3% (Ib), and 2% (Ia). Of 135 erythromycin- resistant S. agalactiae, ermB was detected in 105 isolates, mefA in 20 isolates, and ermTR in seven isolates; most type V isolates harbored the ermB gene, Ib type isolates had an equal distribution of resistance genes, type III isolates accounted for 70% of all isolates carrying mefA genes, and one fourth of type VI isolates had mefA genes.

Analysis for Group B Streptococci Isolated from Bacteremic Patients / 대한임상미생물학회지

BACKGROUND: Group B streptococci (GBS) is known to be major cause of neonatal meningitis and bacteremia, and the infections also has been increasing in adults, particularly those with serious underlying diseases. This study is designed to define the trend of infection rate by year, underlying conditions, clinical outcome of group B streptococcal bacteremia, and to compare the distribution of age, sex, and serotype and antimicrobial susceptibility between invasive and noninvasive GBS infections. METHODS: We analyzed the medical records of 36 cases with group B streptococcal bacteremia between 1990 and 2003, and compared the distribution of age, sex, serotype and antimicrobial susceptibility between invasive and noninvasive GBS infections with GBS strains stocked from 1990 to 2000 at Wonju Christian Hospital. RESULTS: Of 36 GBS bacteremia patients, four (11.1%) patients were early-onset neonatal infection, 9 (25.0%) were late-onset neonatal infection, and 23 (63.9%) were older than 30 years of age. In the 23 adult patients, 19 (82.6%) patients had one or more underlying diseases, and liver cirrhosis and diabetes mellitus were the most common underlying diseases. There is no significant difference of antimicrobial susceptibility and serotype distribution of GBS between invasive and noninvasive infections. CONCLUSION: Bacteremia caused by GBS were prevalent in adult patients with chronic underlying diseases. In neonate, late-onset bacteremia was more common than early-onset bacteremia.

Antimicrobial Resistance and Serotypes in the Clinical Isolates of Group B Streptococci / 대한임상미생물학회지

BACKGROUND: This study is designed to provide data on the trend of resistance by year of isolation in the clinical isolates of group B streptococci(GBS) during recent eight years and to elucidate the relationship between serotypes and antimicrobial resistance patterns. METHODS: The minimal inhibitory concentrations (MIC) of seven antimicrobial agents and serotypes for 150 strains of GBS isolated from clinical specimens between 1990 and 1997 were investigated. RESULTS: The resistance rate of 150 clinical isolates of GBS were 20.0% to clindamycin, 16.0% to erythromycin, 4.0% to chloramphenicol, and 95.3% to tetracycline. None was resistant to penicillin, ceftriaxone, or vancomycin. Of the 24 isolates resistant to erythromycin, 20 (83.3%) were resistant to clindamycin. Resistance rates of erythromycin according to serotypes in decreasing order were 69.2% (V), 23.2% (III), and 3.5% (Ib). All serotypes Ia and II were susceptible to erythromycin and clindamycin. CONCLUSIONS: Striking emergence of resistant strains to erythromycin and clindamycin in our clinical isolates of GBS was mainly due to sudden increase of serotype V and III which shows multi-drug resistance phenotype.

Colonization Rate and Serotypes of Group B Streptococci in First Trimester of Pregnancy / 대한임상병리학회지

BACKGROUND: Group B streptococci (GBS) are the most common cause of sepsis and meningitis in newborns in the United States and Europe, and maternal colonization rate of GBS is the most important factor of group B streptococcal neonatal infections. But, in Korea, studies on the maternal colonization rate of GBS are rare due to low incidence of neonatal group B streptococcal infections, particularly, data on colonization rate of GBS during first trimester is nearly absent. The aim of this study was to establish the rates of maternal carriage of GBS and the distribution of GBS serotypes in first trimester of pregnancy. METHODS: During the period of June to December 1997, we studied women attending private clinic. A total of 309 women in first trimester were enrolled in the study. Cotton swab specimens from vagina and cervix were placed to new Granada tube medium. The new Granada tube medium with specimen swab was incubated in 5% CO2 atmosphere at 35degreesC. For the identification of GBS, the colonies showing orange color on new Granada tube medium were tested with Streptex group B Streptococcus reagent (Wellcome Diagnostics, UK). Serotyping was done by Hemolytic Streptococcus Group B Typing Sera (Denka Seiken, Japan). The typing sera used in this study were Ia, Ib, II, III, IV, and V. RESULTS: Of the pregnant women in first trimester, 2.3% (7/309) were colonized with GBS, and all seven women who colonized GBS were positive in vagina and cervix at the same time. Frequency of serotype III and Ib were 71.4% (5/7) and 29.6% (2/7), respectively. Serotypes Ia, II, VI, and V were absent. CONCLUSIONS: Maternal carriage rate of GBS in first trimester of pregnancy was 2.3%, and serotype III was the most common serotype. Serotypes Ia, II, VI, and V were absent.

Serotypes and Biochemical Reaction Patterns of Group B Streptococci / 대한임상병리학회지

BACKGROUND: This study is designed to provide data on the trend of serotypes of group B streptococci (GBS) isolated from clinical specimens during recent eight years and to elucidate the relationship between biochemical reactions and serotypes of GBS. METHODS: Serotyping, pigment production test, CAMP test, hippurate hydrolysis, and hemolysis test were performed for 150 GBS isolates from clinical specimens during March 1990 to February 1998. The typing sera used were Ia, Ib, II, III, IV, and V. Pigment production was detected by new Granada tube medium. The CAMP test and hippurate hydrolysis were performed by standard technique. Hemolytic patterns of GBS were determined on sheep blood agar and human blood agar plate. RESULTS: GBS were frequently isolated from cervix, urine, wound (pus), and blood. Striking increase of GBS isolates were notified from 1996 to 1997 period. Identification rates of GBS serotypes were Ib (38.0%), III (37.3%), Ia (9.3%), V (8.7%), nontypable strains (4.0%), and II (2.7%) in decreasing order. The proportion of serotype III increased markedly from 1996. Serotype V was not isolated until 1996, and ranked third in 1997. Seven (4.7%) isolates were nonhemolytic, and six of seven isolates revealed serotype III. Two (1.3%) isolates that were negative in both CAMP test and hippurate hydrolysis were serotype II. CONCLUSIONS: Clinical microbiology laboratories relying on beta hemolysis or pigment production for initial detection of GBS may underestimate the isolation rate of GBS and the proportion of serotype III which hardly makes hemolysis. It is therefore recommended that laboratories providing cultures for the GBS of genitalia specimens supplement other detection methods such as CAMP test or immunologic methods.

Trend of isolation and serotypes of group B streptococci in Korea

Group B streptococci (GBS) neonatal infection, a prevalent disease in western countries, is considered rare in Korea. GBS neonatal infection is known to be often due to serotype III organisms, but the serotypes in Korea have not been reported. In this study, GBS were frequently isolated from specimens of genitalia, urine and various pus. Among the 186 isolates 14 (7.5%) were from neonates, two with concomitant bacteremia and meningitis and one with pneumonia. Frequently isolated GBS serotypes were Ib (9.2%), Ib/c (26.6%) and III/R (23.9%). Change of frequently isolated serotypes during the study was noted, but JM9 which became increasingly isolated in Japan was not found. It is concluded that less prevalence of severe neonatal GBS infection in Korea is not due to the absence of serotype III, but possibly due to low genital carriage rate of GBS by pregnant women.