Evaluation of CHROMagar™ StrepB: A new chromogenic agar medium for aerobic detection of Group B Streptococci in perinatal samples

Poisson, Didier-Marc; Chandemerle, Marion; Guinard, Jérôme; Evrard, Marie-Liesse; Naydenova, Diana; Mesnard, Louis

doi:10.1016/j.mimet.2010.06.008

Cited by 14 publications

(22 citation statements)

References 26 publications

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“…The growth of some bacteria with the characteristic color of GBS, as described previously [2][3][4][5] and in the study, was investigated further. Briefly, 55 GBS strains, 10 S. thoraltensis, 10 S. porcinus, 20 S. pyogenes, 20 Staphylococcus aureus, and 20 Staphylococcus intermedius recovered from previous studies and stored at À80 8C were inoculated into THB at an original concentration of 10 5 CFU/ml.…”

Section: Bacterial Identification Of Presumptive Gbs Strainsmentioning

confidence: 99%

“…1 ChromID Strepto B agar (STRB) is one such chromogenic agar developed for the screening of GBS in vaginal/rectal specimens. 2,3 It is selective against Gram-negative bacilli, staphylococci, and yeasts. However, some strains of Streptococcus thoraltensis, Streptococcus porcinus, and Streptococcus pyogenes have been reported to produce colonies of a characteristic color too.…”

Section: Introductionmentioning

confidence: 99%

“…However, some strains of Streptococcus thoraltensis, Streptococcus porcinus, and Streptococcus pyogenes have been reported to produce colonies of a characteristic color too. [2][3][4][5] Therefore, the manufacturer recommends that suspected colonies are confirmed using a biochemical or immunological test. Matrixassisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), based on different protein profiles characteristic of each microorganism, has been investigated for the identification of GBS and an almost 100% accuracy reported.…”

Section: Introductionmentioning

confidence: 99%

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Use of MALDI-TOF mass spectrometry for rapid identification of group B Streptococcus on chromID Strepto B agar

Shi

Zhang

et al. 2014

International Journal of Infectious Diseases

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Section: Bacterial Identification Of Presumptive Gbs Strainsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Use of MALDI-TOF mass spectrometry for rapid identification of group B Streptococcus on chromID Strepto B agar

Shi

Zhang

et al. 2014

International Journal of Infectious Diseases

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“…The procedure requires at least an additional 24 h of culture time compared to that for direct plating on selective agar, and isolated GBS-like colonies require further identification with ancillary tests, e.g., the CAMP factor or B antigen test (11). Furthermore, identification of GBS-like colonies on blood agar requires laboratory expertise, particularly when they are mixed with other microflora (16). Considering methods to decrease the GBS detection time, studies have shown that direct plating on colistin-nalidixic agar (CNA) is a low-cost alternative for GBS recovery, albeit with a lower sensitivity that has ranged from 59% to 83% (17)(18)(19).…”

mentioning

confidence: 99%

“…The use of chromogenic media may improve the yield of GBS while reducing labor costs and turnaround time. The clinical sensitivities of these media vary from study to study, with most studies reporting 93% to 98% for CA (16,21), 40% to 91% for Granada medium (12,18,22), and 88% to 95% for chromID Strepto B agar (13,18). The aim of this study was to evaluate direct plating on CA and CNA and selective broth enrichment for the isolation of GBS in swabs from pregnant women.…”

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confidence: 99%

Evaluation of Trans-Vag Broth, Colistin-Nalidixic Agar, and CHROMagar StrepB for Detection of Group B Streptococcus in Vaginal and Rectal Swabs from Pregnant Women in South Africa

et al. 2013

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d Maternal vaginal colonization with group B streptococcus (GBS) is a major risk factor for invasive GBS infection in newborns.The CDC-recommended method for detecting GBS colonization is to culture vaginal and rectal swabs in a selective broth followed by subculture on blood agar or a selective medium. A high incidence of antimicrobial resistance in the fecal microflora can compromise the recovery of GBS from the selective broth. Here, we compared CHROMagar StrepB (CA), Columbia colistinnalidixic agar (CNA), and Trans-Vag selective broth enrichment for the isolation of GBS from 130 vaginal and 130 rectal swabs from pregnant women. The swabs were randomized for plating first on either CA or CNA, and they then were inoculated in Trans-Vag broth. GBS was cultured from 37.7% of the vaginal swabs and 33.1% of the rectal swabs. There were no differences in the detection rates for the vaginal swabs between CA (31.5%), CNA (26.2%), and the selective broth (30.0%). The sensitivities in relation to a composite score were 83.7%, 69.4%, and 79.6%, respectively. However, recovery of GBS from the rectal swabs was significantly higher from CA (29.2%; P < 0.0001) and CNA (23.8%; P ‫؍‬ 0.002) than from the selective broth (9.2%). The sensitivities were 88.4%, 72.1%, and 27.9%, respectively. The order of plating on the solid medium was significant (P ‫؍‬ 0.003), with GBS detection rates of 30.8% and 24.6% when swabs were plated first and second, respectively. These findings show that a selective broth is not suitable for the recovery of GBS from rectal swabs in settings such as ours, due to masking of the GBS colonies by persistent microflora. Infection by group B streptococcus (GBS) is one of the most common infections in newborns (1). Maternal colonization has been found to be a major risk factor for invasive GBS disease within 6 days of birth. Approximately 10 to 40% of pregnant women are colonized with GBS in either the vagina, the rectum, or both areas (2). The rate of peripartum transmission of GBS to newborns of colonized women is approximately 50%, after which 1 to 2% of these newborns develop invasive GBS infection in the first week of life (3, 4). The Centers for Disease Control and Prevention (CDC) has recommended that all pregnant women be screened for rectovaginal carriage of GBS at 35 to 37 weeks' gestation to identify women who should receive intrapartum antimicrobial prophylaxis (IAP). When successfully implemented, IAP targeted at GBS-colonized pregnant women has reduced the incidence of invasive GBS disease by 86 to 89% (5-7). The sensitivities of screening methods for the identification of maternal carriage of GBS depends on the timing of specimen collection, the source of the specimen, and the culture technique used. Optimally, specimens should be collected as close to delivery as possible. The use of vaginal and rectal swab specimens has been shown to yield higher GBS culture-positivity rates than vaginal swabs alone or cervical specimens (8-10). The current CDC recommendation for the isolation of GBS from v...

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Group B streptococcal carriage, antimicrobial susceptibility, and virulence related genes among pregnant women in Alexandria, Egypt

Sadaka

Aly

Meheissen

et al. 2018

Alexandria Journal of Medicine

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2018) Group B streptococcal carriage, antimicrobial susceptibility, and virulence related genes among pregnant women in Alexandria, a b s t r a c t Background and aim: Group B Streptococcus (GBS) has emerged as a leading cause of illness and death among neonates. The study was conducted to estimate the prevalence of recto-vaginal carriage of GBS among pregnant women at 35-37 weeks, gestation, to describe GBS antimicrobial susceptibility profile and to investigate selected virulence genes by PCR. Subjects and methods: Two-hundred pregnant women at 35-37 weeks of gestation attending antenatal clinic at Al-Shatby University Hospital were enrolled in the study. Both vaginal and rectal swabs were collected from each subject. Swabs were inoculated onto CHROMagar TM StrepB and sheep blood agar plates. All GBS isolates were subjected to antimicrobial susceptibility testing using disc diffusion. Disc approximation test was performed to detect erythromycin resistance phenotype (MLSB). GBS virulence genes scpB, bac, bca, and rib were identified by PCR. Results: Among the 200 pregnant women, 53 (26.5%) were identified as GBS carriers. All carriers had vaginal colonization (100%), four (7.5%) had combined recto-vaginal colonization. None of the carriers had rectal colonization alone. All isolates (100%) were susceptible to penicillin, ampicillin, ceftriaxone, cefotaxime, cefepime, vancomycin, and linezolid. On the other hand, 43.4%, 28.3%, 22.6%, and 15% of isolates were resistant to levofloxacin, azithromycin, erythromycin, and clindamycin respectively. Out of 12 erythromycin resistant isolates, six isolates had constitutive while two had inducible MLSB resistance. scpB was identified in 100%, rib in 79.2%, and bac in 35.8% of GBS isolates. None of the isolates possessed the bca gene. Conclusion: Introduction of GBS screening in Egyptian pregnant women is recommended. Penicillin or ampicillin is still the antibiotic of choice for intrapartum prophylaxis. Ó 2017 Alexandria University Faculty of Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Evaluation of CHROMagar™ StrepB: A new chromogenic agar medium for aerobic detection of Group B Streptococci in perinatal samples

Cited by 14 publications

References 26 publications

Use of MALDI-TOF mass spectrometry for rapid identification of group B Streptococcus on chromID Strepto B agar

Use of MALDI-TOF mass spectrometry for rapid identification of group B Streptococcus on chromID Strepto B agar

Evaluation of Trans-Vag Broth, Colistin-Nalidixic Agar, and CHROMagar StrepB for Detection of Group B Streptococcus in Vaginal and Rectal Swabs from Pregnant Women in South Africa

Group B streptococcal carriage, antimicrobial susceptibility, and virulence related genes among pregnant women in Alexandria, Egypt

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