Evolution of Staphylococcus aureus resistance to erythromycin in Denmark, 1959 to 1988: correlations between characteristics of erythromycin-resistant bacteraemia strains.

Abstract

In an attempt to characterize erythromycin-resistant Staphylococcus aureus we present the intricate relationships between the following factors: phage type, period of isolation, antibiogram, minimum inhibitory concentration (MIC) to erythromycin, inducible or constitutive resistance, spectinomycin susceptibility, hospital- or community-acquired infection, and mortality rate. We studied 718 cases of bacteraemia with erythromycin-resistant S. aureus, occurring between 1959 and 1988. Central factors were phage type pattern, period of isolation, and antibiogram. Between 1959 and 1973 the majority of the erythromycin-resistant strains were multiresistant and belonged to the 83A complex and the related group III. They were mainly inducibly resistant, spectinomycin resistant, and had intermediate MICs (1-4 mg l-1) to erythromycin. The majority of these strains came from hospital-acquired infections and still exist today, although in decreased numbers. By contrast, erythromycin-resistant S. aureus isolated in recent years are usually co-resistant only to penicillin and more rarely also to tetracycline. These strains have inducible resistance, are spectinomycin susceptible, and have a high erythromycin MIC. They are isolated both from hospital- and community-acquired infections. Strains with constitutive resistance to macrolides occurred at a stable low level (13%) during the whole observation period and always had high MICs to erythromycin. The mortality rate among patients with S. aureus bacteraemia due to an erythromycin-resistant strain was only associated with the year of infection and decreased from 61% in the first 15-year period to 40% in the subsequent 15 years.

• Authors: H Westh, A M Knudsen, A Gottschau, V T Rosdahl
• Journal: The Journal of hospital infection (J Hosp Infect) Vol. 18 Issue 1 Pg. 35-43 (May 1991) ISSN: 0195-6701 [Print] England
• PMID: 1679070 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Erythromycin
• Spectinomycin

Topics

• Bacteriophage Typing (methods)
• Cross Infection (microbiology, mortality)
• Denmark
• Drug Resistance, Microbial
• Erythromycin (pharmacology)
• Microbial Sensitivity Tests
• Models, Biological
• Phenotype
• Sepsis (microbiology)
• Species Specificity
• Spectinomycin (therapeutic use)
• Staphylococcal Infections (microbiology, mortality)
• Staphylococcus aureus (classification, drug effects)
• Time Factors