Purpose The coronavirus disease (COVID-19) outbreak has created a global health crisis. Secondary pulmonary bacterial infection is a COVID-19 complication, increasing morbidity and mortality. This study aimed to determine the pathogens, antibiotic susceptibility patterns, and risk factors for mortality in hospitalized COVID-19 patients. Patients and Methods This retrospective study used secondary data from patients’ electronic medical records at Hasan Sadikin General Hospital and Santo Borromeus Hospital between March 2020 and March 2021. Overall, 2230 hospitalized COVID-19 patients were screened, and 182 of them who were hospitalized ≥48 hours with a procalcitonin level of ≥0.25 ng/mL were enrolled. Culture examination was performed on sputum samples to determine pathogen and antibiotic susceptibilities. Univariate and multivariate analyses were used to determine mortality-related risk factors in hospitalized COVID-19 patients. Results The prevalence of secondary pulmonary bacterial infections in COVID-19 patients was 8.2%, with 161/182 pathogen growth from sputum samples. Mainly gram-negative bacteria (64.8%) were present, including Acinetobacter baumannii (31.9%), Klebsiella pneumoniae (19.8%), and Pseudomonas aeruginosa (8.8%). High rate of multidrug-resistant (MDR) pathogens was found among isolate (45.9%), ie carbapenem-resistance A. baumannii (CR-Ab) was 84.2%, extended-spectrum β-lactamase (ESBL) among K. pneumoniae was 61.1%. Secondary infection of MDR pathogens was associated with a higher risk of mortality (AOR 5.63, p = 0.001). Other associated factors were age ≥60 years, ventilator use, and female gender. Conclusion Gram-negative bacteria are the predominant pathogens causing secondary pulmonary bacterial infection in COVID-19 patients, implying nosocomial infection. High resistance to first-line antimicrobial drugs was observed in Gram-negative bacteria and Gram-positive bacteria. High rate of MDR pathogens was found among isolate and was associated with a significant risk of mortality.