Selective antenatal screening for toxoplasmosis and the latex agglutination test

SUMMARYRecent publicity concerning congenital toxoplasmosis has generated a demand for serological assessment of pregnant women. Many laboratories are requested to undertake primary screening in these cases. We assessed the latex agglutination test (LAT) findings in 158 specimens with detectable toxoplasma specific IgM derived from pregnant women. The LAT titres ranged from 16 to ≥ 4000 reflecting the variable antibody response observed in acute toxoplasmosis. We recommend that non-reference laboratories test specimens from pregnant women using the LAT at a screening dilution of 1:16 and select all reactive samples for detailed investigation.

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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

The Egyptian Journal of Medical Microbiology ◽

10.12816/0053806 ◽

2018 ◽

Vol 27 (4) ◽

pp. 7-11

Author(s):

Abdelraouf , Nada S. ◽

Khattab , Mona A. ◽

Atallab , Makram F. ◽

Abd El Rahman , Rehab M.

Keyword(s):

Pregnant Women ◽

Rapid Detection ◽

Group B Streptococcus ◽

Latex Agglutination ◽

Agglutination Test ◽

Latex Agglutination Test ◽

Near Term ◽

Group B ◽

Colonization Status

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Toxoplasma antibody titers by ELISA and indirect latex agglutination test in pregnant women

The Korean Journal of Parasitology ◽

10.3347/kjp.1996.34.4.233 ◽

1996 ◽

Vol 34 (4) ◽

pp. 233 ◽

Cited By ~ 14

Author(s):

Jae Sook RYU ◽

Duk Young MIN ◽

Myoung Myoung AHN ◽

Han Gyoo CHOI ◽

Sang Chul RHO ◽

...

Keyword(s):

Pregnant Women ◽

Latex Agglutination ◽

Agglutination Test ◽

Latex Agglutination Test ◽

Antibody Titers

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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

Journal of Medical Microbiology ◽

10.1099/jmm.0.066738-0 ◽

2014 ◽

Vol 63 (10) ◽

pp. 1395-1399 ◽

Cited By ~ 6

Author(s):

Nahed Ghaddar ◽

Wadha Alfouzan ◽

Elie Anastasiadis ◽

Tamima Al Jiser ◽

Saad Eddine Itani ◽

...

Keyword(s):

Pregnant Women ◽

Group B Streptococcus ◽

Latex Agglutination ◽

Agglutination Test ◽

Latex Agglutination Test ◽

Chromogenic Medium ◽

Predictive Values ◽

Vaginal Swabs ◽

Chromogenic Agar ◽

Group B

This study was undertaken to evaluate chromogenic medium and a direct latex agglutination test (DLA) for detection of Group B Streptococcus (GBS) in the vaginal specimens of pregnant women, and to ascertain the prevalence of GBS in this population in Kuwait and Lebanon. Vaginal swabs, collected from women at 35–37 weeks of gestation, were cultured on 5 % sheep blood agar (SBA), colistin nalidixic acid agar (CNA), Strept B Select chromogenic agar (SBS) as well as Lim enrichment broth in 168 cases in Lebanon while only SBA was used for 1391 samples in Kuwait. In addition, vaginal samples from 102 GBS-positive and 20 GBS-negative women near the time of delivery were collected in Kuwait for evaluation of the DLA test. During the study period, the prevalence of GBS colonization was determined to be 20.7 % (288/1391) in Kuwait while 18.4 % (31) of 168 pregnant women in Lebanon had vaginal cultures positive for GBS. By direct plating of vaginal swabs on the three media used, the isolation rates of GBS were 51.6, 64.5 and 77.4 % on SBA, CNA and SBS, respectively, which increased to 90.35, 93.1 and 96.8 %, respectively, following subculture in Lim broth after 18 h of incubation. The sensitivity of the DLA test was found to be dependent on the density of GBS colonization, resulting in 100 % sensitivity and 100 % specificity for heavy (>102 c.f.u. per swab) and moderately heavy (50–100 c.f.u. per swab) growth of GBS. However, for vaginal specimens yielding <50 c.f.u. per swab, the sensitivity, specificity, positive and negative predictive values of the DLA test were 100, 55.5, 63.6 and 100 %, respectively. In conclusion, a chromogenic agar, such as SBS, and a DLA test can be used for rapid detection of GBS in pregnant women. The DLA test, in particular, could prove to be a useful tool for immediate detection of GBS in women near delivery so that intrapartum antibiotic prophylaxis can be initiated.

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Assessment of different methods for diagnosis of Group B streptococci during pregnancy

Obstetrics & Gynecology International Journal ◽

10.15406/ogij.2020.11.00526 ◽

2020 ◽

Vol 11 (5) ◽

Author(s):

Ahmed Rashwan

Keyword(s):

Pregnant Women ◽

Latex Agglutination ◽

Agglutination Test ◽

Latex Agglutination Test ◽

Diffusion Method ◽

Conventional Pcr ◽

Third Trimester ◽

Pcr Assay ◽

Vaginal Swabs ◽

Kappa Value

Objectives: To compare the different diagnostic techniques used to detect GBS colonization in pregnant women in late third trimester after thirty five weeks and to detect the frequency of GBS colonization among a sample of pregnant Egyptian women. Patients and methods: Vaginal swabs from the lower third of vagina were collected from 100 pregnant women in the late third trimester. Isolation of the organism by culture on selective media and confirmation by latex agglutination test and detection of CAMP factor by conventional PCR were compared. GBS isolates were tested by double disk diffusion method and D-zone test simultaneously for susceptibility to erythromycin and clindamycin and inducible clindamycin resistance for intrapartum antibiotic prophylaxis (IAP). Results: 25 participants (25%) were positive for GBS by culture in Lim broth with subculture onto TSA supplemented with 5% defibrinated sheep blood, while 75 participants (75%) were negative. Of the 25 GBS isolates, 19 (76%) were sensitive to erythromycin, 3 (12%) were intermediate and 3 (12%) were resistant. Of the 25 GBS isolates, 15 (60%) were sensitive to clindamycin, 2 (8%) were intermediate and 8 (32%) were resistant. Fourteen isolates (56%) were sensitive to both erythromycin and clindamycin whereas 3 (12%) were resistant to both (cMLSB). Latex agglutination test for GBS detection from the 24 hours incubated Lim broth was positive in 25 cases (25%). GBS was detected in 9 cases (9%) by the conventional PCR assay done directly from vaginal swabs specimens. Sensitivity, specificity, PPV and NPV for latex agglutination from the inoculated broth and PCR assay are 100%, 100%, 100%, 100% and 36%, 100%, 100%, 82.4% respectively. Latex agglutination test from the inoculated broth showed a statistically significant perfect agreement (100.0%) with culture with Kappa value 1.0 and 95% CI (1.0 – 1.0). PCR assay also showed a statistically significant but moderate agreement (84.0%) with culture with Kappa value 0.458 and 95% CI (0.253 – 0.662). Conclusion: Detection of GBS colonization by latex agglutination test from incubated selective broth directly is comparable to the gold standard (culture) as regards accuracy. PCR offers a rapid and highly specific method for detection of GBS colonization especially in intrapartum settings for administration of IAP in non-screened pregnant females; however, sensitivity is low resulting in a low NPV.

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