<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>

Abstract

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.

Diagnostic performance of two chromogenic media for Streptococcus agalactiae screening in pregnant women.

“…In the current study, we found that 25.89% (29/112) of the pregnant women who underwent the screening were colonized with GBS. These results were concordant with other studies carried out in Egypt such as the study done in Benha university hospital by Tash and co-workers (2019) which showed a prevalence rate of 28% [14], also another study was carried out by El Shahaway and colleagues (2019) at Zagazig university hospital which showed a prevalence rate of 23.5% [15]. Similarly, another study performed by Sadaka and his team (2017) at Alexandria reported a prevalence rate of 26.5% for GBS [16].…”

Contribution of vaginal infection to preterm premature rupture of membrane and adverse pregnancy outcome

“…Heavy bacterial growth from vaginal swab in our study showed highest prevalence of S. agalactiae (18.8% of participants). Vaginal carrier rate of S. agalactiae among Egyptian pregnant females was reported in a previous study to be 23.5% [30]. In our study it was revealed in vaginal swab of 25% of pregnant females with PPROM.…”

Rapid Classification of Multilocus Sequence Subtype for Group B Streptococcus Based on MALDI-TOF Mass Spectrometry and Statistical Models

“…GBS colonization in pregnant women is a major risk factor for neonatal and infant infections (Burcham et al, 2019). The most common epidemiological analysis of GBS infections is the latex agglutination (LA) assay using the specific surface capsular polysaccharide (CPS) antibodies for serologic typing (El et al, 2019). The commercial LA kits sometimes are unable to serotype the GBS isolates with low expression of CPS, methods for genoserotyping with both serotyping and PCR amplification of the capsular gene was developed accordingly (Poyart et al, 2007;Imperi et al, 2010).…”