Prevalence and patterns of multidrug-resistant bacteria isolated from sputum samples of patients with bacterial pneumonia at a tertiary hospital in Tanzania

Abstract

Abstract Background Antimicrobial resistance affects the treatment of several bacterial infections, including pneumonia. This subsequently increased the morbidity and mortality rates of patients with bacterial pneumonia, especially in resource-limited settings. In this study, we aimed to determine the patterns of multidrug-resistant (MDR) bacteria isolated from the sputum samples of patients with bacterial pneumonia attending a tertiary hospital in Tanzania. Methodology A retrospective cross-sectional study was conducted. It involved reviewing the laboratory sputum data in the laboratory information system at Muhimbili National Hospital in Tanzania. The sputum samples were previously processed using standard methods (culture, Gram staining, and biochemical tests) to isolate and identify the bacteria. At the same time, antibiogram profiles were determined using antimicrobial susceptibility tests. Bacterial isolates that expressed MDR patterns were identified. Demographic information was collected from patients' medical records. We used the chi-square test to determine factors associated with MDR. A p-value < 0.05 was considered significant. Results We retrieved and analysed 169 laboratory records of patients with a provisional clinical diagnosis of bacterial pneumonia confirmed in the microbiology laboratory. Nearly 98% of the records were from adult patients. The patients’ mean age was 48.3 years and 17.3 standard deviations. About 84% of the isolated bacteria were Gram-negative; the most predominant was Klebsiella pneumoniae (59/142; 41.5%). The predominant Gram-positive bacteria was Staphylococcus aureus (25/27; 92.6%). Furthermore, 80 out of 169 (47.3%) bacteria were MDR; Klebsiella pneumoniae (32.5%) was predominant. In addition, 50% of Staphylococcus aureus was methicillin resistance. MDR bacterial pneumonia was highly observed in patients admitted to the Intensive Care Unit (p < 0.05). Conclusions Although our study was limited by variations in the number of bacterial isolates subjected to the same antibiotic drugs and a lack of information on risk factors such as occupation, smoking history, and marital status, we observed that a high proportion of bacterial pneumonia is caused by MDR Gram-negative bacteria in our local setting. These results inform the need to improve infection prevention control measures in hospitals to reduce the burden of MDR bacteria in our settings and other similar resource-limited settings.

Keywords

• Multidrug resistance
• Pneumonia
• Gram-negative bacteria