Abstract
BackgroundTo investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections.MethodsAll isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles.ResultsIn total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB.Conclusion S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB.
Highlights
Streptococcus agalactiae (Group B streptococcus, GBS) is an opportunistic pathogen that colonizes the lower digestive and urogenital tracts of healthy people and can be isolated from the genitourinary and gastrointestinal tracts of up to 35% of healthy adults [1,2]
56 S. agalactiae isolates were identified in 863 pregnant women (6.5%)
The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively
Summary
Streptococcus agalactiae (Group B streptococcus, GBS) is an opportunistic pathogen that colonizes the lower digestive and urogenital tracts of healthy people and can be isolated from the genitourinary and gastrointestinal tracts of up to 35% of healthy adults [1,2]. In the last 40 years, S. agalactiae has been the most common pathogen responsible for maternal and neonatal infections. Maternal intrapartum S. agalactiae colonization is a primary risk factor for early-onset S. agalactiae infection in infants. In the absence of any intervention, 1–2% of infants born to S. agalactiae-colonized mothers are estimated to develop early-onset S. agalactiae infection, including neonatal pneumonia, sepsis, and meningitis [6,7,8]. Severe S. agalactiae infections can result in neonatal mortality or permanent disability [9]. Antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections
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