Pseudomonas aeruginosa infection in human immunodeficiency virus infected patients

Objectives: (1) To determine the incidence and outcome of Pseudomonas aerug inosa infection in HIV-infected patients. (2) To study the antimicrobial su sceptibility of P. aeruginosa isolates in this particular population. (3) T o identify risk factors for these infections. Patients and Methods: a retrospective case-control study performed in a 28- bed infectious-diseases unit in a 940-bed university hospital. All cases we re defined as HIV-infected patients with severe infections due to P. aerugi nosa, including bacteriemia, lower or upper respiratory tract infections, i nfections related to a central venous catheter, and cutaneous/muscular infe ction. Each case was matched with an HIV-seropositive control not infected by P. aeruginosa and hospitalized on the same dates as the cases. Results: one thousand and thirty-five HIV-infected patients were hospitaliz ed during the study period. A first severe P. aeruginosa infection was docu mented in 41 patients, giving an overall annual incidence note of 2.51 epis odes per 100 admissions. Forty of the 41 case notes were available for anal ysis. They consisted of 17 cases of bacteraemia, four upper respiratory tra ct infections, 10 lower respiratory tract infections, three catheter-relate d infections, and six cutaneous/muscular infections. Of these 40 cases, 60% were nosocomial and the remainder were community-acquired. The overall mor tality rate was 22% (47% in bacteraemic forms). Twenty five percent of pati ents relapsed after an average of 37 days. The case-control comparison show ed that AIDS was more frequent among the cases (92% vs. 74%, P = 0.04), who also had a lower PN count (P = 0.005), and a lower CD4 cell count (15.7 +/ - 18.8/mm(3) vs. 118 +/- 211/mm(3); P = 0.0007). The number of days spent i n hospital in the previous 3 months (29.3 +/- 20.7 vs. 19.7 +/- 14, P = 0.0 4) was significantly higher among the cases. In a multivariate analysis, ex amining treatments received in the previous month, only co-trimoxazole [OR = 5.5 (1.1-26.9)], penicillins [OR = 5.2 (1.1-25.3)], steroids [OR = 5.5, ( 1.2-25.5)] and a CD4 cell count below 50/mm(3) [OR = 13.2 (1.4-129.4)] were identified as risk factors. Conclusion: P. aeruginosa infection is a not frequent bacterial disease in highly immunodeficient HIV-infected patients, It is frequently fatal and mu st be borne in mind in the advanced stages of HIV disease, especially when patients have received co-trimoxazole (trianthoprim-sulphamethoxazole), pen icillins or steroids.