A high frequency of macrolide-lincosamide-streptogramin resistance determinants in Staphylococcus aureus isolated in South Korea.
Genes conferring resistance to one of the macrolide-lincosamide-streptogramin (MLS) antibiotics may confer cross-resistance to others, because they have similar effects on bacterial protein synthesis. In Korea, over 70% of Staphylococcus aureus isolates are methicillin-resistant and erythromycin-resistant methicillin-resistant S. aureus (MRSA) is also prevalent. We investigated the frequency of MLS resistance in erythromycin-resistant S. aureus isolates. A total of 682 isolates of S. aureus were collected in a nationwide antibiotic resistance survey. Susceptibility to erythromycin, clindamycin, and quinupristin/dalfopristin was tested by disk diffusion. In all, 37% of the methicillin-susceptible S. aureus (MSSA) and 97% of the MRSA isolates were resistant to at least one of the MLS antibiotics, whereas all were susceptible to quinupristin/dalfopristin. Out of 518 strains that were resistant to erythromycin, 60 clindamycin-susceptible (30 MSSA, 30 MRSA) and 44 clindamycin-resistant isolates (14 MSSA, 30 MRSA) were selected at random from these strains. Thirteen genes related to MLS resistance were detected in these isolates by PCR. Of the 104 MSSA and MRSA strains tested, 98 harbored one or more erm gene. The most common was erm(A), with erm(C) next. But, msr(A), lnu(A), and mef(A) were rare and no resistance to streptogramin A was encountered.
Kim
Hong Bin
HB
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, 110-744, Republic of Korea.
Lee
Bobin
B
Jang
Hee-Chang
HC
Kim
Sung Han
SH
Kang
Cheol In
CI
Choi
Young Joo
YJ
Park
Sang Won
SW
Kim
Bong Su
BS
Kim
Eui-Chong
EC
Oh
Myoung-Don
MD
Choe
Kang Won
KW
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005838:Genotype; D006801:Humans; D007723:Korea / Q000453:epidemiology; D055231:Lincosamides; D018942:Macrolides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D016133:Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D025361:Streptogramins / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D055231:Lincosamides; D018942:Macrolides; D025361:Streptogramins