Use of PCR in detection of Mycobacterium avium complex (MAC) bacteremia: sensitivity of the assay and effect of treatment for MAC infection on concentrations of human immunodeficiency virus in plasma.
We evaluated the sensitivity and specificity of a PCR-based qualitative test for the rapid diagnosis of Mycobacterium avium-M. intracellulare complex (MAC) bacteremia in patients with AIDS disease. Eleven subjects with newly culture-proven MAC bacteremia had the following tests performed at biweekly intervals during the first 8 weeks of therapy: blood culture, Mycobacterium-specific PCR, and quantitative human immunodeficiency virus (HIV) viral-load testing. Mycobacterium genus-specific biotinylated primers were used to amplify a sequence of approximately 582 nucleotides within the 16S rRNA genes of M. avium and M. intracellulare. Detection of the amplified product was performed with an oligonucleotide probe-coated microwell plate combined with an avidin-horseradish peroxidase-tetramethylbenzidine conjugate-substrate system. While not as sensitive as BACTEC culture, PCR detected 17 of 18 specimens which grew >/=40 organisms/ml (94.4% sensitivity) and 9 of 16 specimens which grew </=40 organisms/ml (56.3% sensitivity). No clear change in HIV viremia occurred in response to successful treatment of patients' MAC bacteremia. Use of the PCR test allowed detection of MAC bacteremia in 1 day, with a sensitivity similar to those of quantitative blood culture techniques, and it may prove useful for rapid screening of suspected cases. HIV viremia was unaffected by 8 weeks of MAC therapy.
MacGregor
R R
RR
Infectious Diseases Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania. 19104-6073, USA. macgregr@mail.med.upenn.edu
Dreyer
K
K
Herman
S
S
Hocknell
P K
PK
Nghiem
L
L
Tevere
V J
VJ
Williams
A L
AL
D017088:AIDS-Related Opportunistic Infections / Q000097:blood / Q000188:drug therapy / Q000382:microbiology*; D000328:Adult; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000097:blood / Q000188:drug therapy / Q000382:microbiology*; D005260:Female; D006678:HIV / Q000187:drug effects; D006801:Humans; D008297:Male; D015269:Mycobacterium avium Complex / Q000302:isolation & purification*; D015270:Mycobacterium avium-intracellulare Infection / Q000097:blood / Q000188:drug therapy / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012367:RNA, Viral / Q000097:blood; D012680:Sensitivity and Specificity; D019562:Viral Load
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D012367:RNA, Viral