Evaluation of StrepB Carrot Broth versus Lim Broth for Detection of Group B Streptococcus Colonization Status of Near-Term Pregnant Women (original) (raw)
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PLOS ONE, 2015
Group B streptococcus (GBS), which commonly colonizes the female genital tract and rectum, can cause infections in newborns with varying severity, possibly leading to death. The aim of the present study was to evaluate Hitchens-Pike-Todd-Hewitt (HPTH) medium performance for GBS screening in pregnant women. A descriptive analytical cross-sectional study was performed with 556 pregnant women, of which 496 were at 35-37 weeks of gestation and 60 were at 38 weeks of gestation. The study was conducted from September 2011 to March 2014 in northern Paraná, Brazil. Vaginal and anorectal clinical specimens from each pregnant woman were plated on sheep blood agar (SBA) and seeded on HPTH medium and Todd-Hewitt enrichment broth. Of the 496 pregnant women at 35-37 weeks of gestation, 141 (28.4%) were positive for GBS, based on the combination of the three culture media and clinical specimens. The GBS colonization rates that were detected by each medium were 22.2% for HPTH medium, 21.2% for SBA, and 13.1% for Todd-Hewitt enrichment broth. Of the 60 pregnant women at 38 weeks of gestation, seven (11.7%) were positive for GBS. These results demonstrate that HPTH medium and SBA were more sensitive than Todd-Hewitt enrichment broth for GBS screening in pregnant women and good GBS recovery in culture, indicating that the two media should be used together for vaginal and anorectal specimens.
BMC Infectious Diseases, 2010
Background: Streptococcus agalactiae (group B streptococcus; GBS) is a significant cause of perinatal and neonatal infections worldwide. To detect GBS colonization in pregnant women, the CDC recommends isolation of the bacterium from vaginal and anorectal swab samples by growth in a selective enrichment medium, such as Lim broth (Todd-Hewitt broth supplemented with selective antibiotics), followed by subculture on sheep blood agar. However, this procedure may require 48 h to complete. We compared different sampling and culture techniques for the detection of GBS.
Comparative Clinical Pathology, 2012
This study aimed to compare the sensitivity of different culture methods from three different anatomic sites and to evaluate the sensitivity of polymerase chain reaction (PCR) assay targeting the 16 S ribosomal RNA gene in detection of group B streptococcus (GBS) colonization in pregnant women. From 100 pregnant women at 35-37 weeks of gestation, three cotton swabs were used to obtain vaginal, rectal, and rectovaginal (RV) specimens and plated onto Columbia agar with colistin and nalidixic (CNA), group B streptococcus differential agar (GBSDA), and chromID Strepto B agar (CA), with and without Lim broth enrichment. PCR assay was done on the RV swabs. The overall GBS colonization rate was 29 % by culture and 31 % by PCR. GBS positivity for RV sampling (100 %) was significantly higher than detection on the basis of vaginal sampling (50 %), but not significantly higher than for rectal sampling (82 %). Direct plating of the rectovaginal swab on CNA, GBSDA, and CA resulted in detection of 74, 58, and 100 % of the carriers, respectively, whereas subculturing of Lim broth yielded 65, 59, and 83 % positivity, respectively. Using GBS culture as the "gold standard," the sensitivity of PCR was 100 %, and specificity was 97 %. We found that the inoculation of RV secretions directly onto CA is the most rapid, easy, and sensitive method than that of Lim broth enrichment. Also, we found that group B streptococci can be detected rapidly and reliably by a PCR assay of rectovaginal secretions from pregnant women.
Group B Streptococcus detection in pregnant women via culture and PCR methods
Revista da Sociedade Brasileira de Medicina Tropical
Group B Streptococcus (GBS), a source of neonatal infection, colonizes the gastrointestinal and genitourinary tracts of pregnant women. Routine screening for maternal GBS in late pregnancy and consequent intrapartum antibiotic prophylaxis have reduced the incidence of early-onset GBS neonatal infection. The aim of this study was to evaluate the performance of PCR, compared to culture (gold standard), in GBS colonization screening of pregnant women, and to establish the prevalence of GBS colonization among this population. Vaginal introitus and perianal samples were collected from 204 pregnant women, between the 35th and 37th weeks of pregnancy, at the Obstetrics and Gynecology Unit of the University of Caxias do Sul General Hospital between June 2008 and September 2009. All samples were cultured after enrichment in a selective medium and then assayed by culture and PCR methods. The culture and PCR methods yielded detection rates of vaginal/perianal GBS colonization of 22.5% and 26%,...
Background and Objective: Group B Streptococcal infection is an important cause of neonatal morbidity and mortality. Early detection of perinatal vagino-rectal (VR) carriage of Group B Streptococcus (GBS) is important in the management of newborn infections. The objective of the study was to evaluate Culture, antigen detection and Polymerase chain reaction for detection of Group B Streptococcus in Pregnant women. Settings and Design: Observational descriptive study was done in a tertiary care hospital in Southern India. Materials and Methods: Vagino-rectal (VR) swabs were collected from 50 women at 35 to 37 weeks of gestation. Culture in a selective Lim enrichment broth with subsequent culture on 5% sheep blood agar, Conventional PCR assay and antigen detection method were performed. The performance of antigen detection and PCR methods were compared with culture. Statistical analysis: Statistical analysis was performed by Chi-Square test. Results: GBS cultures were positive for 16% of the specimen (8 out of 50). Considering culture as a gold standard, Sensitivity, Specificity, Positive predictive value and Negative predictive value of antigen detection was 100%, 92.86%, 72.73%, 100% and similarly for that of PCR was 100%, 45.23%, 25.80%, 100%, respectively. Conclusion: Antigen detection method was the rapid, sensitive and specific test for the detection of GBS colonizers during pregnancy.
2021
Vaginal colonization of Group B Streptococcus (GBS) is associated with preterm births and neonatal sepsis. Thus, routine screening of GBS in prenatal care is recommended. Chromogenic media are useful in rapid and sensitive screening for GBS. herein, we evaluated the performance of Carrot broth for the detection of GBS in vaginal swabs of pregnant women. In all 20/201 (9.9%) vaginal swab samples were positive in the carrot broth. 17/20 (85%) and 19/20 (95%) samples yielded colonies on Blood agar and Crome agar respectively. However, 16s rRNA sequencing revealed that none of the carrot broth positive cultures had sequence similarities to the Enterococcus faecalis and not GBS. Furthermore, Enterococcus faecalis was detected by PCR in DNA isolated from the corresponding uncultured vaginal swabs samples, while GBS could be detected by PCR only in 4 samples. Thus carrot broth-based culture can lead to false-positive detection due to the presence of Enterococcus faecalis.
Journal of laboratory physicians
Aims: Group B Streptococcus (GBS) is one of the most common causes of neonatal sepsis throughout the world. Reports of vaginal colonization of GBS in India are few and variable. A study was conducted on pregnant women in a tertiary care hospital to compare various methods for isolation of GBS, to study the prevalence of GBS in pregnant women in third trimester, and to determine risk factors for GBS colonization. Settings and Design: Observational descriptive study. Materials and Methods: High vaginal swabs from 150 pregnant women in their third trimester were used to compare three methods for isolation of GBS viz. direct culture on 5% Sheep Blood agar, direct culture on selective Columbia Blood Agar and culture in LIM enrichment broth with subsequent culture on 5% Sheep Blood agar. A history of associated risk factors was also taken. Statistical Analysis Used: Statistical analysis was performed by Chi-square test. Results: Isolation was best from LIM enrichment broth with subsequent culture on 5% Sheep Blood Agar. Prevalence of GBS colonization by using culture method was 12.67%. Most frequently associated risk factor was intrapartum fever (42.11%). Conclusions: Standard Culture Method using LIM enrichment should be adopted as standard practice for isolation of GBS from vaginal swabs.
Group B streptococcus colonisation in pregnant women at Dr. George Mukhari Hospital, South Africa
Southern African Journal of Infectious Diseases, 2016
The aim of the study was to estimate group B streptococcus (GBS) colonisation in pregnant mothers using selective enrichment broth and solid media for culturing GBS. Vaginal and rectal swabs were collected from 413 pregnant women for GBS culture at recruitment stage. Direct plating and enrichment broth culture methods were compared by using the same swab samples. The swabs were cultured on colistin nalidixic agar (CNA) plate and incubated at 37°C and examined after 18-24 h. The samples which were culture negative on a CNA agar plate were then inoculated into a Todd-Hewitt enrichment broth to recover any GBS present that was not recovered on the solid agar. With the CNA agar plate, the samples were cultured separately to enable identification of colonised sites such as vaginal sites or rectal sites. Rectal and vaginal swabs were inoculated into Todd-Hewitt enrichment broth at the same time in the same tube. The GBS colonisation rate in pregnant women was 30.9% (128/413). The CNA agar plate recovered 45.3% (58/128) of the GBS isolates, whereas 54.7% (70/128) isolates were recovered from Todd-Hewitt broth. Pregnant women of various ages were found to be at risk of GBS colonisation. The colonisation rate was however highest among women of 25-29 age groups as compared with other age groups. Detection of group B streptococcus improved when both rectal and vaginal swabs were collected for laboratory analysis. The simultaneous use of Todd-Hewitt broth and CNA plate also improved the yield of group B streptococcus.
Clinical Infectious Diseases, 2004
Group B streptococcus (GBS) remains the leading cause of infectious morbidity and mortality in infants born in the United States, especially among black infants. Because a newborn can acquire GBS during and after delivery, the Centers for Disease Control and Prevention (CDC) recommends that pregnant women be screened for rectovaginal GBS colonization during the antepartum period between weeks 35 and 37 of gestation and, if they are colonized, that intrapartum antibiotic prophylaxis be administered. A prospective investigational study was undertaken from 2 May 2006 to 14 August 2006 at three sites to establish the performance characteristics of the Smart GBS LB assay on the SmartCycler II system for detecting GBS colonization in subjects in the antepartum period from combined vaginal/rectal swab-based specimens after broth enrichment. Results were compared to broth enrichment culture and to the predicate device, the BD GeneOhm StrepB direct assay. The collected specimens were randomized for swab testing order. Each swab sample was processed simultaneously by culture, Smart GBS LB assay, and the BD GeneOhm StrepB assay. A total of 310 subjects were enrolled, with 306 subject results included in the study. Compared to enrichment culture, the Smart GBS LB assay demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 98.6%, 90.4%, 77.1%, and 99.5%, respectively. The Smart GBS LB assay demonstrated substantially equivalent or better performance than culture or the predicate device. Screening of broth enrichment fluids by nucleic acid amplification testing requires careful handling during sample processing to avoid possible contamination.