Severity and outcome of HIV-associated Pneumocystis pneumonia containing Pneumocystis jirovecii dihydropteroate synthase gene mutations

Abstract

Background: The impact of Pneumocystis jirovecii (formerly P. carinii) dihydropteroate synthase (DHPS) gene mutations on morbidity and mortality of Pneumocystis pneumonia (PCP) in HIV-positive patients is unclear.

Objective: To determine whether severity and outcome of HIV-associated PCP differs according to DHPS genotype.

Setting: A prospective, observational study in a university-affiliated county hospital.

Patients: The study included 197 patients with 215 microscopically confirmed PCP episodes and successfully sequenced DHPS genotypes; 175 (81%) episodes displayed mutant genotypes.

Main outcome measure: All-cause mortality within 60 days.

Results: The majority of patients (86%) with PCP containing Pneumocystis DHPS mutations survived. Although severity of PCP was comparable, there was a trend for more patients with mutant genotypes than patients with wild-type to require mechanical ventilation (14.3% versus 2.5%; P = 0.056) and to die (14.3% versus 7.5%, P = 0.31). Independent predictors of mortality at baseline were low serum albumin levels [odds ratio (OR), 4.62; 95% confidence interval (CI), 1.63-13.1; P = 0.004] and requiring intensive care within 72 h of hospitalization (OR, 5.06; 95% CI, 1.43-18.0; P = 0.012).

Conclusion: The majority of HIV-infected patients with PCP containing mutant Pneumocystis DHPS genotypes survived. Mortality was related primarily to the underlying severity of illness. However, a trend towards increased mortality in episodes of PCP containing mutant DHPS genotypes was observed and this warrants further study.