Increase of macrolide-resistant Streptococcus pneumoniae-expressing mefE or ermB gene in the nasopharynx among children with otitis media.
OBJECTIVE
To evaluate prevalence of macrolide resistant strains and the genotypes of the resistance among Streptococcus pneumoniae isolated from the nasopharynx of children with otitis media.


METHODS
Retrospective review.


METHODS
A total of 858 S. pneumoniae isolates were collected from the nasopharynx of pediatric patients with acute otitis media at the clinics of Otolaryngology-Head and Neck Surgery, Wakayama Medical University Hospital and six affiliated hospitals in Wakayama prefecture between January 1998 and December 2002. The antibiotic susceptibility patterns were analyzed for penicillin, erythromycin, and clindamycin according to the National Committee for Clinical Laboratory Standards. Macrolide resistance genes of mefE and ermB were determined by polymerase chain reaction of all S. pneumoniae.


RESULTS
Of 858 clinical isolates, 259 (30.1%) were strains without ermB or mefE gene, 279 (32.5%) carrying mefE, 292 (34.0%) carrying ermB, and 28 (3.4%) carrying both genes. There was a strong correlation between phenotypes and the presence of macrolide resistance genes. The macrolide resistance genes were especially frequently identified among penicillin-resistant S. pneumoniae. Strains carrying ermB gene gradually increased from 25% in 1998 to 45% in 2002, with a concurrent decrease in strains carrying mefE from 36% in 1998 to 1999 to 19% in 2002. Strains having mefE were frequently identified among children younger than 2 years old. The current finding suggested that high-level ermB-mediated macrolide resistance in S. pneumoniae is increasing at an alarming rate in pediatric patients with otitis media, especially among young children. Physicians should pay close attention to such macrolide-resistant bacterial pathogens in the antimicrobial treatment of pediatric patients with otitis media.
Hotomi
Muneki
M
Department of Otolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama 641-0012, Japan.
Billal
Dewan S
DS
Shimada
Jun
J
Suzumoto
Masaki
M
Yamauchi
Kazuma
K
Fujihara
Keiji
K
Yamanaka
Noboru
N
D001426:Bacterial Proteins / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D005838:Genotype; D006801:Humans; D018942:Macrolides / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D008780:Methyltransferases / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D009305:Nasopharynx / Q000382:microbiology*; D010033:Otitis Media / Q000378:metabolism* / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics*
D001426:Bacterial Proteins; D018942:Macrolides; C431304:MefE protein, Streptococcus pneumoniae; D008565:Membrane Proteins; D008780:Methyltransferases; C431709:ErmA protein, Bacteria