Factors associated with the risk of upper respiratory tract bacterial infections among HIV-positive patients

BACKGROUND: The risk and characteristics of upper respiratory tract (URT) bacterial infections (URT-BI) among HIV (+) patients is understudied. We analyzed factors associated with its occurrence and the spectrum of culturable pathogens among patients routinely followed at the HIV Out-Patient Clinic in Warsaw. METHODS: All HIV (+) patients with available URT swab culture were included into analyses. Patients were followed from the day of registration in the clinic until first positive URT swab culture or last clinical visit from January 1, 2007 to July 31, 2016. Cox proportional hazard models were used to identify factors associated with positive URT swabs culture (those with p<0.1 in univariate included into multivariable). RESULTS: In total 474 patients were included into the analyses, 166 with culturable URT swab. In general, 416 (87.8%) patients were male, 342 (72.1%) were infected through MSM contact, 253 (53.4%) were on antiretroviral therapy. Median follow-up time was 3.4 (1.3–5.7) years, age 35.2 (30.6–42.6) years and CD4+ count 528 (400–685) cells/μl. The most common cultured bacteria were S. aureus (40.4%) and S. pyogenes (13.9%) (Table 1). Patients with culturable URT-BI were more likely to be MSM (68.5% vs 78.9%; p<0.016), have detectable viral load (20.9% vs 12.0%; p<0.0001) and CD4+ cell count <500 cells/μl (55.2% vs 39.0%; p = 0.003) (Table 2). In multivariate survival analyses detectable viral load (HR3.13; 95%Cl: 2.34–4.19) and MSM (1.63;1.09–2.42) were increasing, but older age (0.63;0.58–0.69, per 5 years older) and higher CD4+ count (0.90;0.85–0.95, per 100 cells/μl) decreasing the risk of culturable URT-BI (Table 2). CONCLUSIONS: Culturable URT-BI are common among HIV-positive patients with high CD4+ count. Similarly to general population most common cultured bacteria were S. aureus and S. pyogenes. Risk factors identified in multivariate survival analysis indicate that younger MSM patients with detectable HIV viral load are at highest risk. In clinical practice this group of patients requires special attention.