title: Characterization of Mucoid and Non-Mucoid Streptococcus pneumoniae Isolated From Outpatients.
abstract: BACKGROUND
  Streptococcus pneumoniae causes pneumonia, sepsis, and meningitis. This study aimed to investigate the clinical characteristics of mucoid and non-mucoid isolates of S. pneumoniae, and to explore the relationship between the isolate phenotypes and their antibiotic susceptibility.
  
  
  METHODS
  Clinical isolates from 3,453 non-repetitive S. pneumoniae (189 mucoid and 3,264 non-mucoid) infections obtained between January 2008 and December 2012 from outpatients at the Kimitsu-Central Hospital were evaluated.
  
  
  RESULTS
  Compared to the non-mucoid isolates, the mucoid phenotypes were more susceptible to certain antibiotics such as erythromycin, clarithromycin, and tetracycline as opposed to clindamycin, chloramphenicol, and rifampicin. The mucoid phenotype was isolated more frequently from schoolchildren, adults, and elderly adults in a variety of clinical sites, including otorrhea, genitalia, pus, and eye discharge than the non-mucoid phenotype. This suggested that mucoid isolates are more likely to be involved than non-mucoid isolates in various local infections. Systemic infection, which indicates invasiveness, was not associated with the mucoid or non-mucoid phenotype.
  
  
  CONCLUSIONS
  The results of this study suggest that mucoid isolates tend to have higher susceptibility than non-mucoid isolates to antibiotics. To the best of our knowledge, mucoid and non-mucoid S. pneumoniae isolates considerably differ in terms of clinical isolation site and age-specific prevalence.
authors.affiliation: Department of Clinical Laboratory, Tokyo Medical and Dental University Hospital of Medicine, Tokyo, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Ogihara
authors.affiliation: Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Saito
authors.affiliation: Department of Clinical Laboratory, Kimitsu Central Hospital, Chiba, Japan.
authors.forename: Teru
authors.initials: T
authors.lastname: Akikura
authors.affiliation: Department of Clinical Laboratory, Kimitsu Central Hospital, Chiba, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Iwama
authors.affiliation: Department of Clinical Laboratory, Kimitsu Central Hospital, Chiba, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: Department of Clinical Laboratory, Kimitsu Central Hospital, Chiba, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Kaji
authors.affiliation: Department of Clinical Laboratory, Kimitsu Central Hospital, Chiba, Japan.
authors.forename: Kyoka
authors.initials: K
authors.lastname: Kakinuma
authors.affiliation: Department of Clinical Laboratory, Kimitsu Central Hospital, Chiba, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antimicrobial susceptibility; Mucoid colony; Streptococcus pneumoniae