Risk Factors for Carriage of Drug-Resistant Streptococcus pneumoniae Among Adults with Cough Undergoing Evaluation for Tuberculosis Disease in Blantyre, Malawi

Abstract

Background Streptococcus pneumoniae is one of the major causes of infectious diseases across the world. It can cause life threatening diseases such as pneumonia to less severe illness such as sinusitis. Carriage is defined as Streptococcus pneumoniae that occurs in the upper airway. It is harmless, however; can cause severe illness and death if it subjugates the immune system. Carriage is common in children and decreases with an increasing age. However, older people are at higher risk of developing carriage due to their compromised immune system. This study investigated the factors associated with the development of carriage of drug resistant Streptococcus pneumoniae in adults and inform strategies for prevention and treatment. Methods This study was a secondary data analysis of a three-arm, individually randomised, open-label, control trial which investigated accuracy and consequences of using Trial- of-antibiotics for TB diagnosis. The primary study enrolled 1,583 adult’s participants who presented with cough of at least 14 days at 2 primary health care centres in Blantyre, Malawi. Nasopharyngeal swabs were collected from the participants and were tested for antibiotics resistance against S. pneumoniae. Descriptive analysis was carried out and we performed univariable and multivariable logistic regressions to determine significant factors associated with the development of carriage of drug- resistant S. pneumoniae. We adjusted for possible confounding factors during multivariable analysis. v Results The study had 1,576 participants for analysis, including 139 participants who tested positive for drug resistant S. pneumoniae. The participants comprised of 635 (40%) males and 941 (60%) females.There were 502 (32%) from Limbe Health Centre while 1073 (68%) were from Ndirande Health Centre. There were 1,309 (83%) participants who were HIV negative, while 221 (14%) were HIV positive and only 46 (2.9%) didn’t know their HIV status. There were 98 (6.2%) participants who had confirmed TB status and 1478 (94%) were not confirmed for TB. In univariable analysis, the following factors were significantly associated with the development of carriage of drug-resistant S. pneumoniae in adults: underweight with OR 1.89 (95% CI: 1.13 – 3.03, p-value= 0.011) compared to not being underweight, having a history of previous TB with OR 2.12 (95% CI: 1.17 – 3.36, p-value= 0.009) compared to no history of previous TB, presence of sweat with OR 1.43 (95% CI: 1.01 – 2.03, p-value= 0.045) compared to absence of sweat, producing sputum with OR 1.69 (95% CI: 1.01 – 2.81, p-value= 0.031) compared to not producing sputum, positive HIV status with OR 1.71 (95% CI: 1.09 – 2.62, p-value= 0.016) compared to negative HIV status and unknown HIV status. In multivariable analysis, having a history of previous TB was the only factor significantly associated with the development of carriage of drug resistant S. pneumoniae in adults with an adjusted OR 1.86 (95% CI: 0.99 – 3.31, p-value 0.044). The study found that the other factors (treatment arm, site, education, fever, chest pain, blood in sputum, weight loss and TB microbiology) were not significantly associated with the development of carriage of drug-resistant S. pneumoniae in adults. Conclusion The study concluded that having a history of previous TB is a risk factor in the development of carriage of drug-resistant S. pneumoniae among older population. Therefore, stakeholders should explore context-specific strategies such as strengthened mycobacterial resistant monitoring mechanisms.