Group B streptococcus (GBS) is an important neonatal pathogen known to be associated with high morbidity and mortality. GBS is a well-known etiology of postpartum infection and recently is considered to be an emerging pathogen in adult patients causes severe sepsis and invasive infections. The aim of this study was to evaluate the rate of clindamycin and erythromycin resistance among GBS isolated from invasive and non-invasive clinical specimens over the past 13 years.
From 2004-to-2016, 134 invasive and 2,660 non-invasive, non-repetitive isolates were included in the study. The identification was done by using Vitek-2 and MIC was determined by E test.
Results: Among 134 invasive isolates, 124 were from blood, 94 from neonates and 30 from adults and 10 were from CSF. Clindamycin resistance rate for invasive GBS isolates were 5.3% in 2004-2006, 5.7% in 2011-2014, 23.7% in 2011-2014 and 43.5% in 2015-2016 with 23 (17.2%) overall resistant rate. The overall resistance rate to erythromycin among invasive strains was (29.4%, n= 42), however, it was 13.2% in 2004-2006, 25.7% in 2007-2010, 55.3% in 2011-2014 and 30.4% in 2015-2016. Resistance pattern to clindamycin and erythromycin of non-invasive GBS isolates were as follow: (4.4% and 8.1%) in 2004-2010, (21.6% and 33.8%) in 2010-2014 and (52.5% and 49.4%) in 2015-2016, respectively. All isolates were sensitive to penicillin, ampicillin, vancomycin and teicoplanin. However, 94.6% and 95.5% were highly resistant to gentamicin and tetracycline, respectively. Six serotypes were identified in invasive GBS isolates, III (28.8%) was the most prevalent, followed by V (20.7%), Ia & II (15.3%), Ib (8.1%), IV (7.2%), VII (0.9%) and 4 (3.6%) were NT. Serotype distribution of the non-invasive GBS was as follow: serotype V (31.4%), III (23.7%) and II (12.7%) were the predominant. A high level clindamycin and - erythromycin resistant invasive GBS strains with MIC > 256 µg/ml were (61.5% &20%) respectively.
Rate of GBS resistance to clindamycin and erythromycin are significantly increased over the study period. These findings should strongly support ACOG recommendations that clindamycin use for intrapartum prophylaxis to be restricted to penicillin allergic women and it necessitates that all GBS isolates to be tested for clindamycin.
H. Al- Otaibi, None