Background: Respiratory Tract Infections account for the majority of exacerbations of chronic obstructive pulmonary disease (COPD). Determining which individuals have a curable cause of infection and when to proceed with microbiologic testing is a crucial aspect of examination. In Iraq, the prevalence of chronic obstructive pulmonary disease among adult smokers is 15.1%, but the disease affects 10% of those over forty. Infections are the main cause of acute exacerbations of chronic obstructive pulmonary disease, accounting for 40% to 60% of instances of exacerbation. Many bacteria are known to cause acute exacerbations of chronic obstructive pulmonary disease worldwide, including Moraxella catarrhalis, Haemophilus influenza, Streptococcus pneumonia, and Pseudomonas aeruginosa.

Aim of the study: The study aims to identify the main bacterial infections related to chronic obstructive pulmonary disease in Baqubah Teaching Hospital Diyala- Iraq.

Patients and Methods: The study was cross-sectional and included 50 patients (33 males and 17 females) who suffered from chronic obstructive pulmonary disease. All patients were recruited from Baqubah Teaching Hospital from 1^st October 2023 to 31^st January 2024. A comprehensive medical examination and a chest examination, including Spirometry, were used to diagnose each of these individuals. Gram staining and culture were done after sputum samples were collected and processed. Vitek II systems were used to identify the main isolates.

Results: the results of this study showed that 13 (33.3%) of patients were infected with Pseudomonas aeruginosa, 11 (28.2%) with Klebsiella pneumonia, and low infections were by Streptococcus pneumonia 4(10.3%) and Staphylococcus aureus 6 (15.4%), while Proteus spp. 3(7.7%), Streptococcus faecalis 1(2.6%), and Streptococcus viridians 1(2.6%), had the lowest rates of bacterial infection, respectively.