Evaluation of chromogenic medium and direct latex agglutination test for detection of group B streptococcus in vaginal specimens from pregnant women in Lebanon and Kuwait

Ghaddar, Nahed; Anastasiadis, Elie; Jiser, Tamima Al; Itani, Saad Eddine; Dernaika, Racha; Eid, Toufic; Ghaddar, Ali; Charafeddine, A.; Dhar, Rita; Hajj, Hiba El

doi:10.1099/jmm.0.066738-0

Cited by 15 publications

(8 citation statements)

References 26 publications

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“…In their study they classified bacterial density quantitatively in contrast to the semiquantitative method in the current study; there may also differences due to LA kit sensitivity and the GBS antigen extraction method between the two studies. Results in the current study are also much lower than those reported by Ghaddar and coworkers 24. On the other hand, many studies proved poor sensitivity and inadequacy of direct GBS antigen detection in vaginal swabs 25…”

Section: Discussioncontrasting

confidence: 82%

<p>Diagnostic performance of direct latex agglutination, post-enrichment latex agglutination and culture methods in screening of group B streptococci in late pregnancy: a comparative study</p>

Shahaway¹,

Maghraby²,

Mohammed³

et al. 2019

IDR

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BackgroundGroup B streptococcus (GBS) is one of the main causes of neonatal sepsis.PurposeEvaluation of the diagnostic performance of direct latex agglutination test (DLA), post-enrichment latex agglutination (LA) test, and direct culture on chromogenic media in rapid identification of GBS carrier in pregnant women in comparison with the conventional post-enrichment CDC-recommended culture method and further to estimate GBS carriage prevalence and its antimicrobial susceptibility.MethodsTwo hundred pregnant women at gestational age (35–37 weeks) were enrolled. Three low vaginal swabs were obtained from each participant. One swab was directly inoculated into Strep B Select (SBS) agar. The second swab was inoculated in enrichment Lim broth for immunological antigen detection by post-enrichment latex agglutination (5 h and 24 h) and subculture for bacteriological detection. The third swab was used for immunological detection of GBS antigen by direct latex agglutination. The isolated GBS was subjected to antimicrobial susceptibility testing.ResultsAmong 200 pregnant women, 47 (23.5%) were GBS carriers. Considering post-enrichment subculture on SBS medium as a gold standard, the sensitivities for post-enrichment 5 h and 24 h LA were 66% and 95.7%, respectively. However, direct cultivation of the vaginal swabs on SBS medium and DLA recorded 83% and 4.3%, respectively, for sensitivity. All GBS isolates (100%) were sensitive to penicillin G, ampicillin, ceftriaxone, and vancomycin. In contrast, 21.3% and 12.8% of isolated GBS were resistant to erythromycin and clindamycin, respectively.ConclusionGroup B streptococcal antigen detection by latex agglutination after 5 h enrichment is a reliable, easy, and relatively rapid method for screening of GBS carriage in pregnant woman not in labor. Latex agglutination after 18–24 h enrichment can be used alternative to standard subculture method for screening GBS carriage.

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Section: Discussioncontrasting

confidence: 82%

<p>Diagnostic performance of direct latex agglutination, post-enrichment latex agglutination and culture methods in screening of group B streptococci in late pregnancy: a comparative study</p>

Shahaway¹,

Maghraby²,

Mohammed³

et al. 2019

IDR

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“…Comparison of SBA, CNA and SCB methods revealed that SCB was the most reliable. The sensitivity of CNA was similar to previous reports [ 6 , 9 ] as was the sensitivity of SCB [ 3 ]. SCB is more expensive than SBA or CNA but processing time is reduced.…”

Section: Discussionsupporting

confidence: 90%

Occurrence and detection method evaluation of group B streptococcus from prenatal vaginal specimen in Northwest China

et al. 2016

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Sensitive and efficient detection of Group B Streptococcus (GBS) colonization in pregnant women is essential for prescription of prophylaxis at the time of delivery as GBS is an opportunistic pathogen known to cause infant mortality. In this report, two studies were conducted on the methods of GBS detection in Shaanxi province, China, a region lacking data for GBS detection and occurrence. For Study 1, 100 GBS culture-positive vaginal swabs were collected from 1,567 pregnant women for evaluation by direct latex agglutination test. In Study 2, 200 GBS vaginal swabs were evaluated by three culture methods (sheep blood agar (SBA), Columbia colistin-nalidixic agar (CNA), and selective carrot broth (SCB)) followed by analysis using a latex agglutination test. GBS was detected in 6.4 % of specimens in Study 1 and 10.5 % of specimens in Study 2. The results of the latex agglutination test in both studies were accurate with samples exhibiting high to moderate GBS growth, but the accuracy declined for samples with low GBS growth. The evaluation of culture methods for GBS detection revealed the sensitivity of SCB (95.2 %, p = 0.004) was significantly higher than that of the SBA medium (57.1 %). The sensitivity reported for SCB (95.2 %) was higher than CNA (76.0 %), but the difference was not statistically significant (p =0.078). These results indicate a selective broth, such as SCB, is ideal for accuracy at low growth levels, but a direct latex agglutination test could be used as an alternative for rapid detection of GBS in circumstances requiring immediate detection.

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“…Hence the test results were dependent on the density of GBS colonization. These result is similar to a comparative study comparing Strept B Select chromogenic agar (SBS) and direct latex agglutination test (DLA) to assure the prevalence of GBS in this population in Kuwait and Lebanon 14 . They found that the sensitivity of the DLA test was found to be dependent on the density of GBS colonization, resulting in 1oo % sensitivity and 1oo % specificity for heavy (>102 c.f.u.…”

Section: Discussionsupporting

confidence: 80%

“…However, for vaginal specimens yielding <50 c.f.u. per swab, the sensitivity, specificity, positive and negative predictive values of the DLA test were 1oo, 55.5, 63.6 and 1oo %, respectively 14 . Thus, we can conclude that SCB can be more accurate than DLA in having the least false negative results.…”

Section: Discussionmentioning

confidence: 92%

The Performance of Strep B Carrot Broth™ Versus Latex Agglutination Test for Rapid Detection of Group B Streptococcus Colonization Status and its Prevalence in Near- Term Pregnant Women

Abdelraouf¹,

Khattab²,

Atallab³

et al. 2018

Egyptian Journal of Medical Microbiology

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Background: Group B Streptococcus (GBS) has been described as one of the commonest causes of the early onset of sepsis among the newborns, which leads to high rate of mortality and morbidity. Centers for Diseases Control (CDC) (2o16) recommended GBS screening for all pregnant women between 35 and 37 weeks of pregnancy, Objectives: This work aims for evaluation of Strep B carrot broth (SCB) versus Latex agglutination technique (LA) as a screening method for early detection of Group B Streptococci colonizing the genital tract of pregnant females Methodology: the present study was conducted on 1oo pregnant women attending the antenatal care clinic of Maternity Hospitals, Faculty of Medicine, Ain shams University. Duplicate vaginal swabs were taken, one for detection of GBS by Strep B Carrot Broth (SBC) and the second swab for detection of GBS by latex agglutination test. Results: The prevalence of GBS was 33% by SCB. SCB had excellent performance compared to LA test, with a sensitivity of 9o.9%, specificity of 1oo%, and negative predictive value (NPV) and positive predictive value (PPV) of 95.7% and 1oo%, respectively. Conclusion: We can use SCB for rapid and reliable GBS screening in pregnancy as it has less false positive results in comparison to other conventional methods. Antepartum GBS screening is highly recommended to reduce the emerging antibiotic resistance among GBS strains METHODOLOGY Patients:The present study was conducted on 1oo pregnant women their age range from 16 years to 40 years (mean 27.8 years) above 35 weeks of gestation, attending the

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Evaluation of chromogenic medium and direct latex agglutination test for detection of group B streptococcus in vaginal specimens from pregnant women in Lebanon and Kuwait

Cited by 15 publications

References 26 publications

<p>Diagnostic performance of direct latex agglutination, post-enrichment latex agglutination and culture methods in screening of group B streptococci in late pregnancy: a comparative study</p>

<p>Diagnostic performance of direct latex agglutination, post-enrichment latex agglutination and culture methods in screening of group B streptococci in late pregnancy: a comparative study</p>

Occurrence and detection method evaluation of group B streptococcus from prenatal vaginal specimen in Northwest China

The Performance of Strep B Carrot Broth™ Versus Latex Agglutination Test for Rapid Detection of Group B Streptococcus Colonization Status and its Prevalence in Near- Term Pregnant Women

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