The Prevalence of Potential Pathogens of Pneumonia in Sputum Specimens from Adult Patients at the University Teaching Hospital in Lusaka, Zambia

Abstract

Background: Pneumonia is a leading cause of morbidity and a significant cause of mortality worldwide. Although information is

available on pneumonia in children in Zambia, the incidence in adults in many parts of Africa including Zambia is unknown. Knowl- edge of the aetiological agents of pneumonia in low-income countries is critical for making rational decisions regarding treatment as aetiology may differ to that of high income countries and result in poor response to therapy. Objective: The purpose of this study was to identify aetiological agents of pneumonia in adult patients who sought health care at the University Teaching Hospital in Lusaka, Zambia. Methodology: We conducted a cross-sectional study from March 2014 to August 2014. Conventional cultured methods and real-time Polymerase Chain Reaction (PCR) were employed in identifying aetiological agents. Demographic data were collected from patients’ laboratory request forms and all data were analysed using SPSS version 16.

Results: A total of 312 samples were received and cultured, 52.9% (165/312) yielded potential pathogens with the most com- mon being Moraxella catarrhalis [26.7% (47/176)], Pseudomonas aeruginosa [25.6% (45/176)], and Klebsiella pneumoniae [18.2%

(32/176)]. Using PCR, 146 samples were analysed and the most common organisms wereHuman cytomegalovirus [24.3% (44/181)], Klebsiella pneumoniae [17.7% (32/181)], Haemophilus influenzae non-type b [16.0% (29/181)], Streptococcus pneumoniae [9.4% (17/181)] and Staphylococcus aureus [9.4% (17/181)]. Other agents, mostly viruses, were also detected. More than one agent was detected in 42% of the specimens analysed by PCR. Detection rates of probable pathogens by Culture and PCR methods were about 30.1% and 69% respectively.

Conclusion: Our study showed a wide variety of potential pathogens including; bacteria, viruses and fungi in sputum specimens ob- tained from patients attending the University Teaching Hospital. Polymerase Chain Reaction detected more organisms than culture.

Some of the specimens yielded multiple organisms which reflects the possibility of multiple causative agents for pneumonia. These

data show the importance of employing better diagnostic methods, such as molecular tools, for identifying potential pathogens associated with pneumonia.