Detection of group B Streptococcus comparison of solid and liquid culture media with and without selective antibiotics

Altaie, Sousan Sayahtaheri; Dryja, Diane

doi:10.1016/0732-8893(94)90082-5

Cited by 27 publications

(10 citation statements)

References 15 publications

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“…There were 8 false-negative NEL cultures (Table 2, samples A, B, F to I, M, and N) and 7 false-negative carrot broth cultures (samples A, B, and J to N), and each had GBS isolated from the same sample when subcultured from carrot broth to Detect (samples A, B, and F to N). This is consistent with previously published studies demonstrating increased performance of broth-enhanced GBS detection methods compared to direct culture (12)(13)(14).…”

supporting

confidence: 82%

Culture-Based Method with Performance Comparable to That of PCR-Based Methods for Detection of Group B Streptococcus in Screening Samples from Pregnant Women

et al. 2013

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We compared five approaches for group B streptococcus (GBS) detection: three culture-based methods and two methods using broth-enhanced real-time PCR. Carrot broth-enhanced subculture to GBS Detect (Hardy Diagnostics, Santa Maria, CA) exhibited sensitivity and specificity comparable to carrot broth-and LIM broth-enhanced real-time PCRs. G roup B streptococcus (GBS) colonization during pregnancy has been implicated as a major risk factor for severe neonatal infections, including sepsis, pneumonia, and meningitis (1, 2). In the United States, the Centers for Disease Control and Prevention recommend screening women between 35 and 37 weeks of pregnancy to determine GBS carrier status and prophylactic antibiotic treatment during labor for women at risk of transmitting this organism (2).Several published studies have demonstrated the usefulness of culture-based (3, 4) and PCR-based (5-10) methods for detecting GBS. We compared five approaches for GBS detection: chromogenic culture detection by Northeast Laboratory GBS agar (NEL; Northeast Laboratory Services, Winslow, ME) and StrepB carrot broth (carrot broth; Hardy Diagnostics, Santa Maria, CA), carrot broth-enhanced subculture to GBS Detect (Detect; Hardy Diagnostics, Santa Maria, CA), and carrot broth-enhanced and LIM broth-enhanced (Remel, Lenexa, KS) real-time PCRs.A total of 211 vaginal/rectal swabs submitted for routine prenatal GBS screenings were evaluated, including 104 BactiSwab double swab transports (Remel, Lenexa, KS) and 107 Eswabs (Copan Diagnostics, Inc., Murrieta, CA). All specimens were directly inoculated on NEL plates using the specific transport swab (Fig. 1). When a BactiSwab double-swab transport was received, both swabs were used to inoculate NEL plates. One swab was placed in the carrot broth (according to the manufacturer's instructions), and the second swab was placed in the LIM broth. When an Eswab was received, both the carrot and LIM broths were each inoculated with approximately 500 l of the Eswab modified Liquid Amies transport solution and the swab was placed in the carrot broth (according to the manufacturer's instructions). NEL plates were incubated anaerobically at 35°C and examined at 18 to 24 h and 48 h for orange colonies (indicative of GBS). Carrot and LIM broths were incubated aerobically at 35°C for 18 to 24 h. Prior to PCR, all carrot broths were examined for any orange color in the broth, which is indicative of GBS, and were subcultured to Detect plates. Detect plates were incubated aerobically at 35°C for 18 to 24 h and examined for any beta-hemolytic colonies, which is a specific characteristic of GBS on Detect regardless of hemolysis exhibited on sheep blood agar. Real-time PCR was performed on the Cepheid SmartCycler system (Cepheid, Sunnyvale, CA) using the BD GeneOhm StrepB assay (Becton, Dickinson, Franklin Lakes, NJ) as described previously for 50 l aliquots of carrot and LIM broths (5). All NEL, carrot broth, and Detect isolates were confirmed GBS positive by performing CAMP tests. CAMP negative isolates were confi...

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confidence: 82%

Culture-Based Method with Performance Comparable to That of PCR-Based Methods for Detection of Group B Streptococcus in Screening Samples from Pregnant Women

et al. 2013

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“…Use of a selective media increases detection of GBS by 50% (40). The recommended method is 24 hours of incubation in selective broth followed by plating on blood agar.…”

Section: Gbs Sampling and Detection Methodsmentioning

confidence: 99%

Group B Streptococcus: Prevention of Early-Onset Neonatal Sepsis

Platt

O’Brien²

2003

Obstetrical & Gynecological Survey

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“…To the best of our knowledge there is no evidence base for this recommendation. Further, data are conflicting as to whether placing the swab into a non-selective transport medium such as Amies or Stuarts transport medium, prior to inoculation into a selective enrichment broth, decreases the yield of GBS 7,8 . Moreover, selective enrichment broth, which enhances GBS growth, has been shown to increase GBS detection by up to 50% 9 .…”

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confidence: 99%

Screening Protocols for Group B Streptococcus: Are TransportMedia Appropriate?

Teese

Henessey

Pearce

et al. 2003

Infectious Diseases in Obstetrics and Gynecology

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Objective: To evaluate group B streptococcus (GBS) detection in an in vitro setting, using a low and controlled inoculum from swabs directly inoculated into a selective medium, as compared to delayed inoculation following a period in a commercial Amies transport medium with charcoal (Venturi Transystem Copan, Italy). Study design: Clinical isolates of GBS (n = 103), were inoculated into the Amies transport medium with charcoal in a concentration of 100 colony-forming units (cfu)/ml (10 cfu/swab). Swabs were then transferred to an enrichment broth (NPC) at time intervals of 0, 2, 4, 6 and 24 hours. Broths were then incubated for 18-24 hours at 35°C in air, before being transferred to New Granada Medium Modified (NGM) for GBS detection and incubated for a further 18-24 hours at 35°C in air. If the characteristic orange pigmented colonies were observed after this period, the specimen was recorded as + (1-10 colonies) or ++ (more than 10 colonies). Results: Overall 92.2% (95/103) of isolates were detected in all tubes and at all times. An additional two isolates were non-hemolytic, non-pigment forming GBS. Of note, 3.9% (4/103) were negative until 2 hours delayed inoculation and 1.9% (2/103) gave inconsistent results, likely due to the low inoculum used. Conclusion: Delayed inoculation into selective enrichment broth following a period in transport medium, even with a low inoculum, gave a similar and acceptable GBS detection rate to direct inoculation. Hence, Amies transport medium with charcoal is an appropriate transport medium to use, where it is not practical for clinical specimens to be directly inoculated into selective enrichment broth and as endorsed in the Centers for Diseases Control (CDC) Guidelines, 2002.

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Detection of group B Streptococcus comparison of solid and liquid culture media with and without selective antibiotics

Cited by 27 publications

References 15 publications

Culture-Based Method with Performance Comparable to That of PCR-Based Methods for Detection of Group B Streptococcus in Screening Samples from Pregnant Women

Culture-Based Method with Performance Comparable to That of PCR-Based Methods for Detection of Group B Streptococcus in Screening Samples from Pregnant Women

Group B Streptococcus: Prevention of Early-Onset Neonatal Sepsis

Screening Protocols for Group B Streptococcus: Are TransportMedia Appropriate?

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