Background
Streptococcus agalactiae (GBS) infection in pregnant women and neonates has been a worldwide concern due to its lethal threat in neonates causing early- and late-onset disease (EOD and LOD). Universal screening of GBS in pregnant mothers for intrapartum prophylaxis (IAP) was launched in 2012 across Hong Kong hospitals and has greatly reduced the incidence of invasive neonatal and pregnant women infections. We report the prevalence of serotypes and antibiotic resistance among pregnant women and neonates with invasive GBS infection in the period 2006-2018 in one of the hospital clusters of Hong Kong.
Methods
Non-duplicate patient isolates of archived GBS strains isolated from neonates (n=73) and pregnant women (n=73) from 2006-2018 in one of Hong Kong’s hospital clusters were serotyped. Antibiotic resistance data by disc diffusion test according to CLSI was obtained where six antibiotics were tested: Ampicillin, Clindamycin, Erythromycin, Levofloxacin, Penicillin, and Vancomycin.
Results
EOD and LOD cases dropped from 8 and 7 cases in 2011 to 1 and 4 cases in the subsequent year respectively. The prevalent serotypes were III (n=44) followed by Ia (n=11) and Ib (n=11). Most of the Ia isolates were sensitive to antibiotics (64%), while 82% and 84% of Ib and III isolates were resistant to erythromycin and clindamycin. Incidence of invasive GBS in pregnant women reduced from 10 cases in 2011 to 5 cases in 2012. The most prevalent serotype was Ia (n=19) followed by III-2 (n=13), Ib and II (n=10 for both serotypes). Serotype Ia strains were mostly sensitive to antibiotics (74%), while 60% of Ib and 54% of III-2 strains showed resistance to clindamycin and erythromycin.
Conclusion
Although IAP reduced incidences of invasive infection in neonates and pregnant women drastically, multidrug resistance persisted in over 70% of the strains in our study. Active surveillance on the change in antibiotic resistance is required to prepare the healthcare sector for improving treatment regimens to this high risk population.