The Effect Of Group A Streptococcus On Maternal And Neonatal Morbidity In Windhoek

ABSTRACT

Purpose of the research: Globally, puerperal infections cause morbidity in 5-10% of all pregnant women each year. To date, there is very little data in Namibia on the colonization and antibiotic susceptibility patterns of S. pyogenes in pregnant women and neonates. This study aimed at determining the prevalence, antimicrobial susceptibility patterns and genetic based resistance of the isolates from pregnant women at 35 weeks to 37 weeks gestation and neonates at 6 week postdelivery follow up at the Windhoek Central Hospital (WCH) maternity ward. Objectives: To determine the prevalence of GAS in pregnant women at 35-37 weeks gestation and neonates in Windhoek, and assess the genetic basis of resistance to antibiotics in those isolates. Results: Out of the 165 screened pregnant women, 15 women (9.1%) were colonized by S. pyogenes. The prevalence of vaginal S. pyogenes in pregnant women was therefore 5.5% and rectal colonization was 3.6% with a median age of 28.9Resistance was observed against clindamycin (93.3%) and penicillin (66.7%). The TetO resistance gene was detected in 100% of the S. pyogenes isolates. Four (26.7%) isolates possessed the TetM resistance gene. No isolates possessed the ErmA, ErmB or MefA resistance genes. Conclusions: This study aimed at determining the prevalence of GAS in pregnant women at 35-37 weeks gestation and the resistance pattern of S. pyogenes isolates. The study concluded that compared to 0.03% found by Mead & Winn, 2000 and 4.8% by Verkaeran et al., 2014 the maternal colonization with GAS in pregnant women at the WCH was 9.1%. The women colonized by GAS were between the ages of >20-≤39, single, from a low income area and interestingly employed. The prevalence of s. pyogenes infections in neonates post delivery,it was found to be 0.0%. Only 18 of the 40 parents approached for consent agreed, the other 22 refused as they argued that the sample collection procedure was invasive and would be traumatic for the neonates. The study found that out of the 15 S. pyogenes isolates tested against erythromycin, penicillin G, tetracycline, clindamycin and vancomycin, resistance to clindamycin was 93.3% and 66.7% with penicillin. Although it was found that all the isolates were sensitive to tetracycline with the disk diffusion test this current study found a low resistance to tetracycline by GAS isolates in the genotypic testing. In conclusion the study showed that vaginal-rectal colonization with GAS was an uncommon finding in pregnant women and neonates at the WCH maternity ward. In conclusion these findings do not necessitate the screening of women in pregnancy and neonate’s post-partum. Recommendations: Further studies with a larger population should be conducted as this might have a more favourable outcome. This in turn would advocate the need to screen pregnant women for GAS vi strongly. Also, addititonal genes encoding resistance associated with S. pyogenes resistance should be analyzed using molecular techniques. Educating the recruited patients on the sample collection in both the women and neonates might have aided in more of them consenting to have swabs taken. A nutrient broth could have been used for the cultivation of the organism after thawing of the isolates. It supports the growth of microorganisms that are not very nutritionally demanding. Gelatin peptone and beef extract provide nitrogen, vitamins, minerals and amino acids essential for growth. Furthermore a DNA extraction kit which would have yielded a higher quality of DNA could have been used instead of the boiling method.