Microbial Aetiology and Risk Factors of Community-acquired Pneumonia in Security-challenged Communities in the Northeast Nigeria

Background: Community-acquired pneumonia is still a major cause of hospital admission in the sub-Saharan Africa. It is primarily due to gram positive organisms and atypical pathogens as well as gram negative organisms. Aim: The aim of the study was to identify the common risk factors of community-acquired pneumonia and the causative pathogens of community-acquired pneumonia among adults in the Northeastern States, Nigeria. Methods: This was a hospital-based cross-sectional analytical study conducted on adult patients seen at the general outpatient clinics and the medical outpatient clinics of a referral Teaching Hospital in Gombe, Northeast Nigeria between June 2017 and January 2018. Hundred patients with clinical and or radiological diagnosis of community-acquired pneumonia who presented to the General Outpatient Clinic and Medical Outpatient clinic of the hospital were recruited. A chest radiograph, sputum culture and multiplex PCR analysis was conducted on all the hundred sputa. Findings: 45(45%) of the patients had one or more identified risk factors of CAP. Of these, HIV 22 (22%), smoking 11(11%), alcohol consumption 2(2%) while 7 (7%) of these patients smoked cigarette and consumed alcohol. Culture diagnosis of CAP was negative in 58 (58%) of cases. The culture positive sputa included gram positive organisms 9 (9%) and gram-negative pathogens 33 (33%). However, with PCR analysis; Streptococcus pneumoniae 23 (23%) and Hemophilus influenzae 6(6%) were the typical pathogens detected, Legionella pneumophila 5 (5%), Chlamydia pneumoniae 3 (3%) and legionella/ chlamydia co-infection 1(1%) were the atypical pathogens identified. Conclusion: The risk factors of pneumonia identified among patients with community-acquired pneumonia in these insurgent facing communities were immunosuppressive illness, smoking and alcohol consumption. The identified microbial aetiologies were Streptococcus pneumoniae, Hemophilus influenzae, Staphylococcus aureus and gram-negative pathogens like Klebsiella pneumoniae, and Pseudomonas aeruginosa. Additionally, atypical pathogens such as the Legionella pneumophila and Chlamydia pneumoniae were also detected.