Characterization of Mucoid and Non-MucoidStreptococcus pneumoniaeIsolated From Outpatients

Abstract

BackgroundStreptococcus 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.MethodsClinical 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.ResultsCompared 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.ConclusionsThe 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.

Properties of Mucoid Serotype 3 Streptococcus pneumoniae From Children in China

“…In our study, mucoid serotype 3 S. pneumoniae was found in children of all ages, but it was more common in the schoolchild group. The mean age of children was more than 5 years old, which was older than the most common age for pneumococcal infection ( Ogihara et al., 2015 ). We suspected that bacteria with a thicker capsule may be more resistant to host phagocytosis, even for the older children.…”