PREVALENCE OF PNEUMOCYSTIS JIROVECII IN SMEAR NEGATIVE SPUTUM SAMPLES AT THE COAST GENERAL TEACHING AND REFERRAL HOSPITAL IN KENYA

Abstract

Pneumocystis jirovecii pneumonia (PJP) is an underdiagnosed opportunistic infection, particularly in TB-endemic regions where clinical manifestations overlap. There are still significant challenges to overcome, despite the fact that rapid culture techniques and tests like the Xpert MTB/RIF assay have improved the ability to diagnose tuberculosis and improved clinical care. These include delayed linkage to care after diagnosis, the ongoing emergence of drug-resistant TB strains, and restricted access to diagnostic tools in low-resource settings. In areas where mycobacterial cultures are inaccessible, smear negative pulmonary tuberculosis is diagnosed using clinical and radiographic criteria, potentially masking opportunistic infections like P. jirovecii due to symptom overlap. This overlap can lead to misdiagnosis, emphasizing the need for reliable diagnostic methods. Additionally, the stage of the disease can affect the sensitivity of diagnostic tools, especially in cases of extrapulmonary and paucibacillary TB. Patients who are TB smear-negative or undergoing TB retreatment present diagnostic challenges due to potential co-infections, often resulting in delayed or incorrect treatment. This study aimed to determine the prevalence of P. jirovecii and to compare the diagnostic performance of traditional staining techniques with polymerase chain reaction (PCR) in sputum samples from TB smear-negative patients at Coast General Teaching and Referral Hospital (CGTRH). The study's findings could inform clinical practices and improve patient outcomes by ensuring the timely identification and treatment of co infections. Besides, P. jirovecii can co-infect with TB. A cross-sectional study utilized sputum samples from TB smear-negative and TB retreatment patients who were smear negative. By identifying co-infections, healthcare providers can better tailor treatment strategies and enhance patient care outcomes. Samples were analyzed microscopically with Toluidine Blue O staining, as well as molecularly through nested PCR targeting the mitochondrial large subunit rRNA (mt LSU rRNA) gene of P. jirovecii. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated, with PCR serving as the reference standard. Among 100 enrolled patients (63 men, 37 women), P. jirovecii was detected in 41% (41 cases) by PCR compared to 29% (29 cases) by Toluidine Blue O staining. Conventional staining showed a sensitivity of 68.3% (95% CI: 54.1%–80.6%) and specificity of 98.3% (95% CI: 90.9%–99.9%), whereas PCR demonstrated higher detection rates. P. jirovecii is prevalent in TB smear negative and retreatment patients, underscoring the need for differential diagnosis in chronic respiratory infections. Given its superior sensitivity and specificity, nested PCR should be incorporated into routine diagnostic protocols, particularly for high-risk patient populations. This could significantly enhance patient outcomes by enabling earlier and more accurate identification of P. jirovecii infections, ultimately guiding appropriate treatment strategies. Effectively integrating these methods will not only streamline the diagnostic process but also foster a deeper understanding of the epidemiology of P. jirovecii in various patient populations. It is advisable to perform multi pathogen diagnosis in these individuals prior to the initiation of retreatment