Prevalence of and Risk Factors for Methicillin-Resistant Staphylococcus aureus (MRSA) Nasal Colonization in HIV-Infected Ambulatory Patients

• Published in: Journal of acquired immune deficiency syndromes (1999) Vol. 48; no. 5; pp. 567 - 571
• Main Authors: CENIZAL, Mary Jo, HARDY, Robert D, ANDERSON, Marc, KATZ, Kathy, SKIEST, Daniel J
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 15-08-2008; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Adult; Aged; AIDS/HIV; Anti-Bacterial Agents - therapeutic use; Bacteria; Bacteriology; Biological and medical sciences; Drug resistance; Epidemiology; Estimates; Female; Fundamental and applied biological sciences. Psychology; Genotype & phenotype; HIV; HIV - physiology; HIV Infections - complications; HIV Infections - microbiology; HIV Infections - virology; Human immunodeficiency virus; Human viral diseases; Humans; Infectious diseases; Male; Medical sciences; Methicillin - therapeutic use; Methicillin Resistance; Microbiology; Middle Aged; Miscellaneous; Nose - microbiology; Prospective Studies; Risk Factors; Staphylococcal Infections - complications; Staphylococcal Infections - drug therapy; Staphylococcal Infections - microbiology; Staphylococcus aureus; Staphylococcus aureus - drug effects; Staphylococcus aureus - growth & development; Staphylococcus aureus - isolation & purification; Viral diseases; Virology; nasal colonization; Prevalence; Microbiology; Epidemiology; S. aureus; MRSA; Bacteria; Micrococcales; Micrococcaceae; Ambulatory; community-onset MRSA; Staphylococcus aureus; Immunopathology; Retroviridae; AIDS; Immune deficiency; Lentivirus; Virology; Infection; Virus; HIV; Viral disease; Risk factor; Human immunodeficiency virus; community-associated MRSA
• ISSN: 1525-4135; 1944-7884
• DOI: 10.1097/qai.0b013e31817e9b79

Estimates of the prevalence of colonization with methicillin-resistant Staphylococcus aureus (MRSA) vary in HIV-infected patients.
HIV clinic patients were prospectively cultured. Bilateral nasal and axillary swabs were plated on BBL CHROMagar MRSA media. Molecular typing was done by pulse-field gel electrophoresis, and staphylococcal cassette chromosomemec typing was determined. A patient questionnaire was conducted to ascertain potential MRSA risk factors; medical records were reviewed.
Fifteen of 146 (10.3%) patients had MRSA nasal colonization; 1 also had axillary colonization. Twelve of 15 isolates were staphylococcal cassette chromosomemec type IV, and 8 of 14 were USA300 or USA400 genotype. MRSA colonization was associated with lower CD4 cell count, not receiving current or recent antibiotics, history of prior MRSA or methicillin-susceptible Staphylococcus aureus infection (P < 0.05 for all), and a trend toward history of hospitalization or emergency department visit in the past year (P = 0.064). Current use of trimethoprim-sulfamethoxazole was protective for colonization: 0 of 29 trimethoprim-sulfamethoxazole recipients were colonized versus 15 of 117 nonrecipients, P = 0.04. In a multivariate logistic regression model, prior infection with either methicillin-susceptible S. aureus (odds ratio = 32.4, 95% confidence interval 3.04 to 345.42) or MRSA (odds ratio = 9.71, 95% confidence interval 2.20 to 43.01), not receiving current or recent antibiotics (odds ratio = 0.026, 95% confidence interval 0.002 to 0.412), and lower CD4 count (odds ratio 0.996, 95% confidence interval 0.992 to 0.999) were associated with MRSA colonization.
The prevalence of MRSA nasal colonization was relatively high compared with prior studies; axillary colonization was rare. Prior staphylococcal infection (methicillin-susceptible S. aureus or MRSA), not receiving antibiotics, and lower CD4 count were associated with MRSA nasal colonization. Trimethoprim-sulfamethoxazole seemed to be protective of MRSA colonization.