Bacteremia due to Staphylococcus aureus with reduced susceptibility to vancomycin

S S Wong; T K Ng; W C Yam; D N Tsang; P C Woo; S K Fung; K Y Yuen

doi:10.1016/s0732-8893(99)00141-8

Bacteremia due to Staphylococcus aureus with reduced susceptibility to vancomycin

Diagn Microbiol Infect Dis. 2000 Apr;36(4):261-8. doi: 10.1016/s0732-8893(99)00141-8.

Authors

S S Wong¹, T K Ng, W C Yam, D N Tsang, P C Woo, S K Fung, K Y Yuen

Affiliation

¹ Division of Infectious Diseases, Department of Microbiology, The University of Hong Kong, Queen Mary Hospital, University Pathology Building, Pokfulam Road, Hong Kong.

PMID: 10764969
DOI: 10.1016/s0732-8893(99)00141-8

Abstract

Four cases of bacteremia caused by Staphylococcus aureus with heteroresistance to vancomycin (hetero-VRSA) were described. In at least two of these four mortalities, the cause of death was temporally related to the hetero-VRSA bacteremia. The vancomycin and teicoplanin MICs of the resistant subpopulations of these four hetero-VRSA were 8 and 24 microg/ml, respectively. All isolates were producers of beta-lactamase, produced penicillin-binding protein PBP2a, and possessed the mecA gene accounting for methicillin resistance. Thickening of the peptidoglycan cell wall was observed by electron microscopy. When ampicillin was combined with vancomycin, in vitro synergism was detected using the checkerboard titration method (epsilonFIC = 0.13). The use of vancomycin plus ampicillin-sulbactam could be a viable option in treating severe hetero-VRSA infection in view of the higher affinity of ampicillin toward PBP2a.

Publication types

Case Reports
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Ampicillin / therapeutic use
Anti-Bacterial Agents / therapeutic use*
Bacteremia / drug therapy*
Bacteremia / microbiology
Bacterial Proteins*
Carrier Proteins / analysis
DNA, Bacterial / analysis
Electrophoresis, Gel, Pulsed-Field
Fatal Outcome
Female
Hexosyltransferases*
Humans
Male
Methicillin Resistance
Microbial Sensitivity Tests
Microscopy, Electron
Middle Aged
Muramoylpentapeptide Carboxypeptidase / analysis
Penicillin-Binding Proteins
Penicillins / therapeutic use
Peptidyl Transferases*
Staphylococcus aureus / drug effects*
Staphylococcus aureus / isolation & purification
Staphylococcus aureus / ultrastructure
Teicoplanin / therapeutic use*
Vancomycin / therapeutic use*
Vancomycin Resistance
beta-Lactamases / analysis

Substances

Anti-Bacterial Agents
Bacterial Proteins
Carrier Proteins
DNA, Bacterial
Penicillin-Binding Proteins
Penicillins
Teicoplanin
Vancomycin
Ampicillin
Peptidyl Transferases
Hexosyltransferases
Muramoylpentapeptide Carboxypeptidase
beta-Lactamases