beta-Lactamase production and genetic location in Staphylococcus aureus: introduction of a beta-lactamase plasmid in strains of phage group II.
Staphylococcus aureus strains of phage group II have increased in frequency in hospital-acquired infections during recent years. A total of 184 penicillin resistant group II strains from bacteraemia cases in the years 1961-1990 were analysed for the amount of beta-lactamase produced and the location of the beta-lactamase gene. Until 1977 all strains investigated had a chromosomally located beta-lactamase gene, but since then a 21 kb beta-lactamase plasmid has increased in occurrence among group II strains, especially among those strains typable only at high phage concentrations [100 x Routine Test Dilution (RTD) and 1000 x RTD]. In 1990, 84% of the group II strains contained this plasmid. Plasmid-containing strains produced more beta-lactamase than strains without the plasmid. S. aureus strains of the 94,96 complex, which since 1984 have decreased in frequency from 18 to 9% in 1993, have remained high producers of beta-lactamase.
Skov
R L
RL
Staphylococcus Laboratory, Statens Seruminstitut, Copenhagen, Denmark.
Williams
T J
TJ
Pallesen
L
L
Rosdahl
V T
VT
Espersen
F
F
D001434:Bacteriophage Typing; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000032:analysis / Q000235:genetics*; D012703:Serotyping; D013045:Species Specificity; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D001618:beta-Lactamases / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics
D001618:beta-Lactamases