The real-time PCR process for detecting group B streptococcus (GBS) in pregnant women, developed by the authors of the University of Medicine and Pharmacy Hospital in Ho Chi Minh City, is fast, accurate and reasonably priced.

          GBS colony identification test

Group B streptococci (GBS) are aerobic Gram-positive bacilli that cause  pharyngitis  ,  pneumonia  , skin wound infections, and sepsis. They are the leading cause of infection and a major cause of morbidity and mortality in newborns. Early GBS infection causes  pneumonia  , sepsis, and  meningitis  . Mother-to-child transmission can occur when pregnant women have GBS infection in the vagina or rectum at the time of labor or rupture of membranes, which is a high and important risk factor for early neonatal infection.

In Vietnam, a number of major maternity hospitals have applied GBS screening for pregnant women in the 35th-37th week and used treatment regimens according to the guidelines of the  US  Centers for Disease Control and Prevention (CDC). Diagnosis and screening for GBS in pregnant women is mainly performed by culture techniques, giving results  after  4-5 days. Only a few hospitals perform GBS screening tests using real-time PCR techniques, giving results within 48 hours. However, this is still a long time, so a screening process with faster results (about 2 hours) is needed to ensure that babies are born safely, avoiding cases of early neonatal infections. To overcome this limitation, a research team at the University of Medicine and Pharmacy Hospital in Ho Chi Minh City has developed a real-time PCR process to detect group B streptococcus in pregnant women.

At Facility 2, University of Medicine and Pharmacy Hospital, Ho Chi Minh City, 259 full-term pregnant women (gestational age over 37 weeks) were swabbed vaginally and rectally to determine the clinical diagnostic values ​​of the optimal real-time PCR procedure in the study. To evaluate the diagnostic value of the real-time PCR procedure, the authors used a culture method  with  a chromogenic medium. Accordingly, GBS colonies had a definite morphology of pink color, even edges, and shiny convex surfaces. In addition, the research team also redesigned the thermal program (to destroy the cell membrane) of the real-time PCR reaction 9 and selected a suitable enzyme system.

The result is an improved real-time PCR procedure that rapidly detects GBS with an accuracy of 96.83%, a sensitivity of 93.94%, and a specificity of 97.93%. This result is comparable to the Sacace commercial kits. The procedure takes approximately 87 minutes per sample (47 minutes faster than using the commercial kit).

The cost of chemicals for a real-time PCR test to detect GBS using a commercial kit is 230,000 VND/test, not including the cost of extraction chemicals. Meanwhile, the cost of chemicals for a GBS test in this study is around 150,000 – 180,000 VND/test. Therefore, the results of the topic can be applied to clinical practice to serve people with the criteria of fast, accurate with appropriate cost, meeting the needs of GBS screening for pregnant women.

Source: NPD (synthesis)