Objective: To describe the microbiological
characteristics of community - acquired
pneumonia (CAP) in patients with type 2
diabetes mellitus treated at Thai Nguyen
National Hospital. Subjects and Methods: A
cross-sectional descriptive study was conducted on
117 inpatients with CAP and a history of type 2
diabetes mellitus, admitted from July 2024 to July
2025 at Thai Nguyen National Hospital. Results:
Positive bacterial cultures were obtained in 35.9% of
cases. Among the 42 culture-positive cases, Gramnegative bacteria accounted for 90.48%, while Grampositive bacteria represented 4.76%. Specifically,
Klebsiella pneumoniae was isolated in 40.9% of cases,
Acinetobacter baumannii in 21.4%, and Pseudomonas
aeruginosa in 4.5%. Gram-positive bacteria included
Streptococcus pneumoniae and Staphylococcus aureus
(1.5%). Fungal isolates of Candida albicans were
detected in 4.5%. Negative cultures were more
frequent in patients with well-controlled diabetes,
whereas positive cultures predominated in poorly
controlled diabetes. The difference was statistically
significant (p < 0.05). Conclusion: The findings
demonstrate a clear predominance of Gram-negative
bacteria, particularly Klebsiella pneumoniae and
Acinetobacter baumannii. Higher rates of positive
cultures were observed in patients with poor glycemic
control, underscoring the importance of blood glucose
management in reducing infection risk. Empirical
antibiotic selection should prioritize coverage against
Gram-negative pathogens, with close monitoring of
antibiotic susceptibility testing and strict glycemic
control. Enhanced screening, preventive measures,
and risk factor management are essential to improve
patient outcomes.