The prevalence of laboratory-confirmed Pneumocystis jirovecii in HIV-infected adults in Africa: A systematic review and meta-analysis

Abstract

Background: The epidemiology of Pneumocystis jirovecii, known to colonize the respiratory tract and cause a life-threatening HIV-associated pneumonia (PCP), is poorly described in Africa. We conducted a systematic review to evaluate P. jirovecii prevalence in African HIV-positive adults with or without respiratory symptoms.

Methods: We searched Medline, Embase, Cochrane library, Africa-Wide, and Web of Science for studies employing PCR and/or microscopy for P. jirovecii detection in respiratory samples from HIV-positive adults in Africa between 1995 and 2020. Prevalence with respiratory symptoms was pooled using random-effect meta-analysis, and stratified by laboratory method, sample tested, study setting, CD4 count, and trimethoprim/sulfamethoxazole prophylaxis. Colonization prevalence in asymptomatic adults and in adults with non-PCP respiratory disease was described, and quantitative PCR (qPCR) thresholds to distinguish colonization from microscopy-confirmed PCP reviewed.

Results: Thirty-two studies were included, with 27 studies (87%) at high risk of selection bias. P. jirovecii was detected in 19% [95% confidence interval (CI): 12-27%] of 3583 symptomatic and in 9% [95% CI: 0-45%] of 140 asymptomatic adults. Among symptomatic adults, prevalence was 22% [95% CI: 12-35%] by PCR and 15% [95% CI: 9-23%] by microscopy. Seven percent of 435 symptomatic adults had PCR-detected Pneumocystis colonization without evidence of PCP [95% CI: 5-10%, four studies]. One study established a qPCR cutoff of 78 copies/5μl of DNA in 305 induced sputum samples to distinguish Pneumocystis colonization from microscopy-confirmed PCP.

Conclusion: Despite widened access to HIV services, P. jirovecii remains common in Africa. Prevalence estimates and qPCR-based definitions of colonization are limited, and overall quality of studies is low.

Keywords: Pneumocystis jirovecii; Africa; HIV.

Figure 1.

PRISMA diagram. AM – antemortem, CINAHL – cumulative index of nursing and allied health, HIV – human immunodeficiency virus, PCP – pneumocystis pneumonia, P. jirovecii – Pneumocystis jirovecii, PM – post-mortem, PRISMA – preferred reporting items for systematic reviews and meta-analysis.

Figure 2.

Pooled prevalence of Pneumocystis jirovecii in symptomatic HIV-positive adults, stratified by laboratory testing method (PCR versus microscopy). PCR – polymerase chain reaction.