Microbial Characteristics of Lower Respiratory Tract Infections in Patients Referred from Primary Care Hospitals

Objective: This study investigated the microbiological characteristics of severe lower respiratory tract infection patients not respond to initial treatment, and were transferred to a tertiary-level hospital.Material and Methods: This was a multicenter, prospective study conducted across four hospitals: Cho Ray, Pham Ngoc Thach, Gia Dinh People’s Hospital, and Can Tho Central General Hospital. Sputum specimens were collected shortly after admission and subjected to culture and real-time PCR testing.Results: Out of the 252 patients, 170 (67.4%) met the criteria for analysis and identification of pathogenic microorganisms. The most frequently isolated pathogens were Streptococcus pneumoniae (S. pneumonia) and Haemophilus influenzae (H. influenzae), comprising of 27.0% and 13.1%, respectively. Antibiotic susceptibility testing was conducted on 55 patients (32.3%). Among these cases, there were 16 instances of S. pneumoniae, 10 cases of Staphylococcus aureus (S. aureus), 10 cases of Pseudomonas aeruginosa (P. aeruginosa), 14 cases of gram-negative enteric bacteria, 2 cases of H. influenzae, 1 case of Moraxella catarrhalis (M. catarrhalis), 1 case of Enterococcus faecium, and 1 case of M. pneumoniae. The antibiogram results revealed significant findings; including a 70% prevalence of extended-spectrum beta-lactamase and 90% occurrence of Methicillin-Resistant Staphylococcus aureus. The data also indicated high resistance rates; such as 90% resistance to erythromycin, 40-80% to ciprofloxacin, 30-80% to ceftazidime, and 30-40% to imipenem.Conclusion: Pathogens associated with LRTIs referred from primary care hospitals encompass S. pneumonia, H. influenza, and S. aureus. At our facility, piperacillin, imipenem, amikacin, vancomycin, and linezolid emerged as the most effective antibiotics for addressing these LRTIs.