Background: Patients hospitalized in the intensive care unit (ICU) have a higher susceptibility to infections. Respiratory infections are the most common nosocomial infections. Rising antibiotic resistance due to indiscriminate use of antibiotics and poor adherence to standard precaution in healthcare facilities compounds the problem. The main aim of this study is to assess microbial patterns and antibiotic resistance from bronchoalveolar lavage specimens in severe pneumonia patients. Methods: This retrospective study was conducted in an Indonesian tertiary care hospital from January 2016-December 2020. Written and verbal informed consent was obtained prior to bronchoscopy procedures. Patients were enrolled if they had severe community-acquired pneumonia (CAP) according to American Thoracic Society (ATS)/Infectious Disease Society of America (IDSA) criteria, had high-risk hospital-acquired pneumonia (HAP), late-onset ventilator-associated pneumonia (VAP), or pneumonia caused by Coronavirus disease (COVID-19). Respiratory specimens via bronchoscopy were inoculated on general semi-sloid thioglycolate media. Testing for antibiotic susceptibility was done using the disk diffusion method. Results: Two hundred and one patients’ data were analyzed. The majority of patients were males (65,17%) and above 60 years of age. The most common type of pneumonia was CAP (39,3%). Neurologic/cerebrovascular disease was the most common comorbidity (35,32%). Acinetobacter baumannii was the most frequently isolated microorganism. Ampicillin/sulbactam and amikacin were found to yield lower microbial resistance. Conclusion: Combination of ampicillin/sulbactam and amikacin appeared effective as initial empirical therapy in severe pneumonia patients. Further studies are needed to evaluate the feasibility and effectiveness of this combined therapy.