Antimicrobial Resistance Levels of Non-Tuberculous Bacteria Isolates from Sputum of TB Patients in Ghana.

Background: Patients with tuberculosis (TB) often harbor diverse bacteria in their sputum, including both commensal and opportunistic pathogens. This study aimed to characterize the sputum microbiota of TB patients before and after the intensive phase of anti-TB treatment and assess changes in bacterial diversity and antibiotic resistance profiles.

Methods: A total of 162 patients with TB (128 males, 34 females; age range 18-82 years) provided sputum samples at baseline, of which 72 provided follow-up sputum after two months of intensive phase treatment. Sputum samples were cultured on standard agar plates, and distinct colonies were identified by Gram staining and bio-typing using MALDI-TOF mass spectrometry. Antibiotic susceptibility testing of the identified Gram-positive and Gram-negative bacteria was performed using the Kirby-Bauer method according to the CLSI guidelines.

Results: At baseline, 209 bacterial isolates were recovered, dominated by Gram-positive bacteria (GPB), particularly Streptococcus oralis (19.6%) and Staphylococcus aureus (13.9%). After treatment, the isolation rate significantly decreased (from 129% to 95.8%; p = 0.000002), with a shift towards Gram-negative bacteria (GNB) dominated by E. coli. High rates of antibiotic resistance were observed for both the GNB and GPB, notably to ampicillin (86.7%), tetracycline (74%), amoxicillin (70.3%), and sulfamethoxazole (63%) for GNP, and PEN (76.9%) for the GPB. 53% of S. aureus isolates were phenotypic Methicillin-resistant S. aureus (MRSA) and 57.7% of suspected extended-spectrum Beta-lactamase (ESBL) producers were confirmed positive, predominantly carrying the blaCTX-M-1 gene.

Conclusion: The observed antibiotic resistance among the identified isolates, including MRSA and ESBL, underscores the need for routine antibiotic susceptibility testing and judicious antibiotic use in Ghana. Further research is needed to explore the long-term consequences of these microbiome shifts on TB treatment outcomes and risk of secondary infections.