High-level aminoglycoside resistance among enterococci and group A streptococci.
The occurrence of high-level aminoglycoside resistance (HLAmR) was determined for 73 enterococci and 54 group A streptococci by the high-load disc method, tube macrodilution and the polymerase chain reaction (PCR). The PCR method revealed the presence of genes coding for aminoglycoside-3'-O-phosphoryltransferase-III (APH(3')-III), aminoglycoside-6'-N-acetyltransferase/2''-O-phosphoryltransferase (AAC(6')/APH(2'')), or both, in 20.6%, 9.6% and 4.1% of the enterococci, respectively. The prevalence of HLAmR to at least one aminoglycoside among local enterococci was 37% (27/73). Only one of 54 Streptococcus pyogenes isolates produced APH(3')-III and exhibited high-level resistance to kanamycin and streptomycin. In general, the three methods yielded comparable results, with only three discrepancies among the 127 isolates examined. High-load disc screening and tube macrodilution proved to be practical, reliable and reproducible, and thus suitable for routine screening. Of 20 Enterococcus faecalis strains tested, all were penicillin-tolerant. Only one of seven penicillin-tolerant S. pyogenes strains was HLAmR. No association between the two forms of resistance was found.
van Asselt
G J
GJ
Dept. of Medical Microbiology, University Hospital, Leiden, The Netherlands.
Vliegenthart
J S
JS
Petit
P L
PL
van de Klundert
J A
JA
Mouton
R P
RP
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial; D016983:Enterococcus / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000235:genetics; D001618:beta-Lactamases / Q000032:analysis
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D001618:beta-Lactamases