Abstract:
Bacterial lower respiratory tract infection pathogens pose a serious health
problem in developing countries including Ethiopia. In, Ethiopia, the trend to manage
Xpert-negative presumptive pulmonary TB cases is empirical.
Objective: This study aimed to determine the prevalence of pathogenic bacteria,
antimicrobial susceptibility patterns, and associated factors of lower respiratory infection
among Xpert-negative presumptive tuberculosis adult patients at Hiwot Fana
Comprehensive Specialized Hospital, Harar, eastern Ethiopia.
Method: A hospital-based cross-sectional study was undertaken from January to April
2024. Convenient sampling technique was used to enroll 371 study participants. Socio-
demographic and other relevant data were collected by using a pretested structured
questionnaire. The collected sputum were inoculated onto blood agar, chocolate agar and
MacConkey. Biochemical tests and Gram staining were used to identify pathogenic
bacteria down to species level. Antimicrobial susceptibility test was performed by Kirby-
Bauer disc diffusion method. Data were entered into Epi data version 4.6 and analyzed by
using Statistical Package for Social Science version 20. Bivariate and multivariable logistic
regression analysis were used to assess the association between outcome and predictor
variables. p -value ≤ 0.05 at 95 % CI was considered statistically significant.
Results: The overall prevalence of pathogenic bacteria of lower respiratory infections was
34.0 % (126/37195% CI; 29.2, 38.8). S. aureus (19.0 %) was the dominant isolates
followed by K. pneumonia (14.3%). S. aureus isolates were highly sensitive to cefoxitin,
ciprofloxacin, and gentamycin and most of them were resistant to penicillin and
tetracycline. Overall, the proportion of multi-drug resistance and its type methicillin-
resistance S. aureus was 39.7% and 16.7% respectively. Educational status (AOR=4.008;
95% CI=1.619, 9.920; p =0.003), history of prior antibiotic usage (AOR=1.866; 95%
CI=1.132, 3.077; p =0.014) and crowded living condition (AOR=5.106; 95% CI=3.028,
8.611; p <0.001) were factors associated with bacterial lower respiratory tract infections.
Conclusion: This study found that Xpert-negative presumptive tuberculosis adult patients
were predominantly infected with other pathogenic bacteria than M. tuberculosis.
Therefore, the routine sputum culture and antibiotic susceptibility testing should be
suggested to ensure favorable treatment outcomes. Promoting education, refraining from
exploiting antibiotics and managing crowded living condition would mitigate lower
respiratory tract infection
