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 ◽  
...  

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.

2013 ◽  
Vol 33 (1) ◽  
pp. 34-38
Author(s):  
B Mishra ◽  
C Mahaseth ◽  
A Rayamajhi

Introduction: Acute bacterial meningitis is one of the leading causes of mortality and morbidity in children. Identification of the causative organism is crucial to its management and outcome. The objective of this study was to see the usefulness of latex agglutination test in the early diagnosis of acute bacterial meningitis. Materials and Methods: A hospital based prospective cross-sectional study was conducted at Kanti Children’s Hospital during December 2004 to August 2005. Cerebrospinal fluid from 150 consecutive clinically suspected cases of acute bacterial meningitis between the age group of 2 months to 14 years were analyzed. Bacterial culture and latex agglutination test was done on cerebrospinal fluid obtained from all 150 suspected cases of acute bacterial meningitis. Latex agglutination test was done using the BD DirectigenTM Meningitis Combo test kit (Becton, Dickinson and company, USA) for Streptococcus pneumoniae, group B Streptococcus, Escherichia coli, Neisseria meningitidis group A,C and Y/ W135, and Hemophilus influenzae type b. Data was analysed by using SPSS Version 11.5. Results: Of the 150 Cerebrospinal fluid samples analysed bacterial culture identified only 4 meningitis cases giving an isolation rate of 1.3% whereas latex agglutination test identified 29 cases giving an isolation rate of 19.3% from 150 samples. Streptococcus pneumoniae, Hemophilus influenzae type b and Group B Streptococcus were the most common causative organism. Conclusion: Latex agglutination test has a better yield, higher sensitivity, provides microbiological diagnosis earlier than the traditional cerebrospinal fluid culture and is easy to perform. DOI: http://dx.doi.org/10.3126/jnps.v33i1.7047 J Nepal Paediatr Soc. 2013;33(1):34-38


2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Ayesha Bahez ◽  
Mohammed Imad Al-Deen Mustafa Mahmud ◽  
Hairul Aini Hamzah ◽  
Hanan Hamimi Wahid

INTRODUCTION: Group B streptococcus (GBS) is a leading cause of maternally-acquired invasive infections in neonates. Nowadays maternal immunization is of utmost demand for prevention of these infections. We undertook capsular serotyping and virulence factor genes identification for local GBS isolates as a pilot study, to identify potential candidates to propagate vaccine development. MATERIALS AND METHODS: This is a descriptive lab -based study to determine GBS serotypes and presence of genes coding virulence factors bca and rib in isolates obtained from symptomatic pregnant women in Hospital Tengku Ampuan Afzan, Kuantan, Pahang, Malaysia. Sixty-two GBS isolates from high vaginal swabs were collected. Latex agglutination test was performed to determine GBS serotypes. Real-time PCR was done to determine the presence of virulence genes. RESULTS: Of the 62 GBS isolates, 77.4% were serologically typeable, and 22.6% were non -typeable. Serotypes Ia and Ib (16.1% each) were the most common capsular types, followed by II, V, and VII (9.7% each), III (8.1%), VI (6.5%), and VIII (1.6 %). Furthermore, 67.7% of the isolates harboured the rib gene while 98.4% possessed the bca gene. CONCLUSION: The five known prevalent serotypes worldwide, do not match the CPS distribution in symptomatic pregnant women in Kuantan. However, the frequency of virulence genes rib and bca is high among our isolates, which if confirmed by further bigger and wider studies makes the proteinaceous vaccine, N-terminal domains of Rib and AlpC a suitable candidate for GBS prevention in this geographical area.


Author(s):  
Ahmed Rashwan

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.


PEDIATRICS ◽  
1995 ◽  
Vol 96 (5) ◽  
pp. 951-954
Author(s):  
Penny M. Adcock ◽  
Ronald I. Paul ◽  
Gary S. Marshall

Background. Identifying febrile children with invasive bacterial infection is difficult in the absence of telltale physical findings. Urine latex agglutination (ULA) tests have been used for rapid, on-site identification of such children. Objectives. To study the performance of ULA tests in identifying children with Haemophilus influenzae, Streptococcus pneumoniae, and group B streptococcus infection and to examine how the results of ULA tests affect patient treatment. Design. Retrospective review. Setting. Urban children's hospital. Patients. All emergency department and hospital patients tested by ULA in 1990, excluding patients in the neonatal units. Results. Of 1629 patients, 36 had positive tests (20 H influenzae, 5 S pneumoniae, and 11 group B streptococcus). Thirteen of these were false positive based on culture results. Although ULA tests demonstrated excellent specificity, their sensitivity was poor. Positive predictive values for bacteremia ranged from 0.346 to 0.600, and negative predictive values ranged from 0.972 to 0.997. The decision to treat with antibiotics was made before ULA test results were available in 19 (53%) of the 36 patients with positive test results. Of 1593 patients with negative test results, 1211 (76%) were admitted to the hospital, and approximately 81% were empirically treated with parenteral antibiotics. Conclusions. In clinical practice, treatment and disposition decisions are frequently made without regard to ULA test results.


1970 ◽  
Vol 9 (4) ◽  
pp. 216-222 ◽  
Author(s):  
Md Abdus Salam ◽  
Dinesh Mondal ◽  
Mamun Kabir ◽  
Rashidul Haque

Background: A new unique latex agglutination test (KAtex) that detects a stable, nonprotein, disease specific parasite antigen in the freshly voided urine of patients suffering from active kala-azar has been introduced by Kalon Biological Ltd. UK. This is absolutely non-invasive method of diagnosis for visceral leishmaniasis and suitable for implementation as a rapid diagnostic tool at the point of care. Objective: Diagnostic potential of KAtex was evaluated among clinically suspected kala-azar patients in an endemic zone of Bangladesh. Methodology: KAtex was done using freshly voided urine according to the manufacturer’s instructions for sixty (60) clinically suspected patients of kala-azar admitted in Rajshahi Medical College Hospital (RMCH), Bangladesh and forty (40) healthy controls during December 2005 to June 2006. Leishmania nested Polymerase Chain Reaction (Ln-PCR) using peripheral blood buffy coat was performed for all study population (100) and Ln-PCR positive cases were considered as confirmed cases of kalaazar. Results: Out of 60 clinically suspected kala-azar patients, 56 were Ln-PCR positive and 53 of 56 Ln-PCR positive cases were KAtex positive (sensitivity, 94.64%; Mantel-Haenszel Chi sq. 79.66, p= 0.0000, confidence interval [CI], >95 to 100%). None of the healthy controls was found positive by Ln-PCR but 2 of 40 were KAtex positive (specificity, 95%; confidence interval [CI], >95 to 100%). The positive and negative predictive values of KAtex were noted as 98.10% and 92.85% respectively. Conclusion: This limited prospective study suggests that KAtex is an absolutely non-invasive urinebased antigen detection test with high sensitivity and specificity and may be useful for screening active kala-azar patients, particularly suitable for field use. Key words: Visceral leishmaniasis; Kala-azar; KAtex; Ln-PCR; sensitivity; specificity. DOI: 10.3329/bjms.v9i4.6688Bangladesh Journal of Medical Science Vol.09 No.4 July 2010 pp.216-222


2011 ◽  
Vol 5 (08) ◽  
pp. 592-595 ◽  
Author(s):  
Vijayan Sharmila ◽  
Noyal Mariya Joseph ◽  
Thirunavukkarasu Arun Babu ◽  
Latha Chaturvedula ◽  
Sujatha Sistla

Introduction: During the last few decades, group B Streptococcus (GBS) has emerged as an important pathogen. The major reservoirs for GBS are the vagina and the peri-anal regions/rectum, and the colonization of these regions is a risk factor for subsequent infection in pregnant women and newborns. Methodology: A prospective study was performed to determine the prevalence of GBS colonization in the vagina and rectum of pregnant women and the antibiotic susceptibility pattern of the isolates. We also aimed to identify risk factors associated with GBS colonization. The vaginal and rectal swabs were inoculated in Todd-Hewitt broth and later subcultured on blood agar for isolation of GBS. Results: A total of 300 pregnant women were enrolled in the study. GBS strains were isolated from seven out of 300 patients, corresponding to a colonization rate of 2.3%. Of the seven patients carrying GBS, isolates were cultured only from vaginal swabs in two cases (28.6%), only from rectal swabs in two cases (28.6%) from both vaginal and rectal swabs in three cases (42.9%). Heavy colonization was present only in 42.9% (3/7) of antenatal women. None of the seven isolates were resistant to penicillin or clindamycin, while one isolate (14.3%) was resistant to erythromycin and five isolates (71.4%) were resistant to tetracycline. Multigravid women and those with previous spontaneous abortion were more frequently colonized by GBS. Conclusion: The GBS colonization rate in our study was low. No resistance to penicillin or clindamycin was seen, while the majority of the isolates were resistant to tetracycline.


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