title: Clinical significance of serotype V among infants with invasive group B streptococcal infections in South Korea.
abstract: BACKGROUND
  Group B Streptococcus (GBS) strains are classified by the polysaccharide capsule, which is an important virulence factor and stimulator of antibody-associated immunity. As GBS infections in neonates may be life-threatening, GBS screening and intrapartum antibiotic prophylaxis have been implemented for prevention. In Korea, there are few reports on the GBS serotype distribution and antibiotic resistance patterns because GBS screening and intrapartum prophylaxis are not done routinely.
  
  
  METHODS
  The serotype distribution and antibiotic resistance of GBS in infants in Korea with invasive bacterial infections were examined for the 19-year period 1995-2013. Isolates obtained previously from hospitals located in three different regions were analyzed for capsular serotype by PCR and sequencing and for antimicrobial susceptibility.
  
  
  RESULTS
  Among 56 isolates serotyped, the most common serotypes were III (44.6%) and V (28.6%), followed by Ia (14.3%), Ib (10.7%), and VI (1.8%). No penicillin-resistant strains were detected, however 51.8% of the strains had resistance to erythromycin and 55.4% showed clindamycin resistance. Resistance was highest (93.8%) to both erythromycin and clindamycin for serotype V; all 15 isolates resistant to erythromycin were cMLSB phenotype and had a high level of resistance to both erythromycin and clindamycin with MIC levels >256μg/ml, and all but one were positive for ermB.
  
  
  CONCLUSIONS
  In this study in Korea, serotype V was identified in a relatively large proportion of GBS isolates and this serotype showed a high level of resistance to erythromycin and clindamycin in a statistically significant majority. Continuous monitoring of changes in clinical disease and molecular characteristics is important for the treatment and prevention of invasive GBS disease in infants.
authors.affiliation: Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea; Department of Pediatrics, Seoul National University Bundang Hospital, 82, Gumi-Ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do, 463-707, Korea.
authors.forename: In Ae
authors.initials: IA
authors.lastname: Yoon
authors.affiliation: Department of Pediatrics, Chonbuk National University Children's Hospital, Chonbuk National University Medical School, Jeonju, Korea; Research Institute of Clinical Medicine of Chonbuk National University - Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Korea.
authors.forename: Dae Sun
authors.initials: DS
authors.lastname: Jo
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Pediatrics, Chungnam National University Hospital, Daejeon, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Cho
authors.affiliation: Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea; Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Hwa
authors.initials: EH
authors.lastname: Choi
authors.affiliation: Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea; Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hoan Jong
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Seoul National University Bundang Hospital, 82, Gumi-Ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do, 463-707, Korea. Electronic address: mdopd@hanmail.net.
authors.forename: Hyunju
authors.initials: H
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D056910:Republic of Korea; D065288:Serogroup; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D002981:Clindamycin; D004917:Erythromycin
keywords: Drug resistance; Infant; Newborn; Serotypes; Streptococcus agalactiae