Macrolide resistance mechanisms and expression of phenotypes among Streptococcus pneumoniae circulating in Italy.
In Italy, macrolide-resistant pneumococci have been isolated at a rate increasing from 6% in 1993 to 31.7% in 1998. A collection of 161 erythromycin-resistant Streptococcus pneumoniae recovered between 1993 and 1997 has now been phenotypically and genotypically characterized. Approximately 90% of these microorganisms possessed a constitutive MLS(B) mechanism of resistance. PCR detected ermB and mefE genes in strains showing MLS(B) and M phenotypes, respectively. Using pulsed-field gel electrophoresis of chromosomal DNA, one dominant restriction profile and its variations were detected in 51 S. pneumoniae isolates collected from different locations, indicating the circulation of a clone characterized by the possession of a great ability to spread.
Marchese
A
A
Institute of Microbiology, University of Genoa, Italy.
Tonoli
E
E
Debbia
E A
EA
Schito
G C
GC
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology*; D007558:Italy; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D013296:Streptococcus pneumoniae / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D004917:Erythromycin