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

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.

scholarly journals 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

2014 ◽  
Vol 63 (10) ◽  
pp. 1395-1399 ◽  
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.

Performance Comparison of a fliCh7 Real-Time PCR Assay with an H7 Latex Agglutination Test for Confirmation of the H Type of Escherichia coli O157:H7†

2009 ◽  
Vol 72 (10) ◽  
pp. 2195-2197 ◽  
Author(s):  
NEELAM NARANG ◽  
PINA M. FRATAMICO ◽  
GLENN TILLMAN ◽  
KITTY PUPEDIS ◽  
WILLIAM C. CRAY
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test ◽  
Escherichia Coli O157 ◽  
Pcr Assay ◽  
E Coli ◽  
Reference Strains ◽  
Pcr Test

Escherichia coli O157:H7 is a foodborne pathogen that causes hemorrhagic colitis and hemolytic uremic syndrome. Positive identification of E. coli O157:H7 is made using biochemical tests and specific antisera or latex agglutination reagents for the O157 and H7 antigens. However, under certain conditions, some E. coli O157:H7 isolates can appear to be nonreactive with H7 antisera and may require multiple passages on motility medium to restore H7 antigenicity. In this study, we compared the performance of a real-time PCR test with that of a method using latex agglutination reagents to detect the presence of the fliCh7 gene or the H7 antigen, respectively, in E. coli O157:H7 isolates. One hundred twenty-six E. coli strains were tested including reference strains and strains isolated from meat. Lyophilized E. coli O157:H7 isolates were rehydrated and were plated on sheep blood agar without passage on motility medium. All strains were analyzed in parallel by a real-time PCR test targeting the fliCh7 gene and by a latex agglutination test that detects the H7 antigen. The real-time PCR assay showed 100% agreement with the H7 status reported for reference strains and E. coli O157:H7 meat isolates. The latex agglutination test results agreed with the H7 status reported for the E. coli O157:H7 reference strains and non-O157:H7 strains, except for one, E. coli O117:H7; however, 42% (42 of 100) of the E. coli O157:H7 meat isolates tested negative for the H7 antigen by latex agglutination. The real-time fliCh7 PCR test can be used to confirm E. coli O157:H7 strains that are not expressing the immunoreactive H7 antigen.

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

1996 ◽  
Vol 34 (4) ◽  
pp. 233 ◽  
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

scholarly journals Usefulness of PCR and Antigen Latex Agglutination Test with Samples Obtained by Transthoracic Needle Aspiration for Diagnosis of Pneumococcal Pneumonia

1999 ◽  
Vol 37 (3) ◽  
pp. 709-714 ◽  
Author(s):  
Amparo García ◽  
Beatriz Rosón ◽  
José Luis Pérez ◽  
Ricard Verdaguer ◽  
Jordi Dorca ◽  
...  
Keyword(s):  
Antibiotic Therapy ◽  
Pneumococcal Pneumonia ◽  
Needle Aspiration ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test ◽  
Pcr Assay ◽  
Simple Method ◽  
Predictive Values ◽  
Culture Techniques

In a large number of cases, the etiology of community-acquired pneumonia (CAP) is not established. Some cases are probably caused byStreptococcus pneumoniae. Transthoracic needle aspiration (TNA) culture has a limited sensitivity which might be improved by antigen detection or gene amplification techniques. We evaluated the capacity of a PCR assay and a latex agglutination test to detectS. pneumoniae in samples obtained by TNA from 95 patients with moderate-to-severe CAP. Latex agglutination and PCR had sensitivities of 52.2 and 91.3%, specificities of 88.7 and 83.3%, positive predictive values of 62.3 and 65.6%, and negative predictive values of 83.3 and 96.5%, respectively, when culture techniques were used as the “gold standard.” When we considered expanded criteria for the diagnosis of pneumococcal pneumonia as a standard for our calculations, latex agglutination and PCR had sensitivities of 53.6 and 89.7%, specificities of 93.0 and 90.0%, positive predictive values of 78.9 and 81.3%, and negative predictive values of 80.3 and 94.7%, respectively. The additional diagnosis provided by the PCR assay compared to latex agglutination was 12.2% (95% confidence interval of the difference from 0.4 to 20.1%). PCR was more sensitive than TNA culture, particularly in patients who had received prior antibiotic therapy (83.3 versus 33.3%). Although PCR is a very sensitive and specific technique, it has not proved to be cost-effective in clinical practice. Conversely, latex agglutination is a fast and simple method whose results might have significant implications for initial antibiotic therapy.

scholarly journals Selective antenatal screening for toxoplasmosis and the latex agglutination test

1990 ◽  
Vol 105 (2) ◽  
pp. 409-414 ◽  
Author(s):  
R. E. Holliman ◽  
K. F. Barker ◽  
J. D. Johnson
Keyword(s):  
Antibody Response ◽  
Pregnant Women ◽  
Congenital Toxoplasmosis ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test ◽  
Antenatal Screening ◽  
Primary Screening ◽  
Acute Toxoplasmosis

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.

Detection of rotavirus in sewage and drinking water by Latex agglutination test

2019 ◽  
Vol 9 (2) ◽  
pp. p8694
Author(s):  
Muhammad Shoaib ◽  
Kokab Furqan ◽  
Sajjad ur Rahman ◽  
Ahsan Naveed ◽  
Amjad Islam Aqib ◽  
...  
Keyword(s):  
Drinking Water ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test
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