Recurrent methicillin-resistant Staphylococcus aureus osteomyelitis: combination antibiotic therapy with evaluation by serum bactericidal titers.
OBJECTIVE
To report on a patient with recurrent methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis and bacteremia successfully treated with combination antibiotic therapy.


METHODS
Two sets of blood cultures from a 55-year-old man with fever, malaise, and low back pain grew MRSA. Radiologic studies of the spine showed bony changes consistent with osteomyelitis. Soon after completing 6 weeks of vancomycin, the patient experienced a recurrence of back pain. Laboratory values included an increase in the sedimentation rate to 53 mm/h and positive blood cultures for MRSA. Vancomycin, gentamicin, and rifampin were administered for 8 weeks. Serum inhibitory and bactericidal titers were more than 1:1024 for both the peak and trough concentrations. Radiologic studies of the spine showed healing osteomyelitis. Two years after completion of antibiotic therapy, the infection has not recurred.


CONCLUSIONS
Antibiotic therapy alone was attempted because the patient was considered a risky surgical candidate. Serum inhibitory and bactericidal titers documented the high in vivo activity of the vancomycin, gentamicin, and rifampin combination. Initiation of vancomycin, gentamicin, and rifampin combination. Initiation of vancomycin therapy led to disappearance of the fever and back pain. Cure was documented by sustained normalization of the erythrocyte sedimentation rate and radiologic evidence of healing.


CONCLUSIONS
Combination antibiotic therapy with vancomycin, rifampin, and low-dose gentamicin (1 mg/kg q12h) may be useful for deep-seated tissue infection caused by MRSA.
Pharmacy Service, Veterans Affairs Medical Center, Pittsburgh, PA 15240, USA.
S L
SL
Aspinall
D M
DM
Friedland
V L
VL
Yu
J D
JD
Rihs
R R
RR
Muder
D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D005839:Gentamicins / Q000627:therapeutic use; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D010019:Osteomyelitis / Q000188:drug therapy* / Q000382:microbiology; D012008:Recurrence; D012293:Rifampin / Q000627:therapeutic use; D015610:Serum Bactericidal Test; D013122:Spinal Diseases / Q000188:drug therapy* / Q000382:microbiology; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D014640:Vancomycin / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D014640:Vancomycin; D012293:Rifampin