Management of respiratory tract infection based on sputum culture results

Tracheostomy is commonly performed in hospitalized patients requiring prolonged mechanical ventilation. Tracheostomy tubes can promote bacterial biofilm formation, potentially leading to local tracheitis or lower respiratory tract infections (RTIs). The distribution of pathogens and their resistance profiles vary by clinical setting, antimicrobial exposure, and patient factors.

To describe the microbiological findings from sputum cultures in tracheostomy patients, assess the prevalence and risk factors for multidrug-resistant organisms (MDROs), and evaluate empiric antibiotic management of RTI episodes.

We conducted a retrospective, single-center study of adults who underwent tracheostomy between 2020 and 2024. Data on patient characteristics, sputum cultures, and RTI management were extracted from electronic health records.

Among 507 patients, 257 (50.7%) had at least one MDRO-positive sputum culture, while 153 (30.2%) had only susceptible organisms. Higher Charlson Comorbidity Index, longer hospital stays, and prolonged antibiotic exposure prior to tracheostomy were independently associated with MDRO isolation (OR 1.18, 1.01, 1.06, respectively; p<0.05). The most commonly isolated organisms were Enterobacterales, Pseudomonas aeruginosa, Acinetobacter species, Staphylococcus aureus, and Corynebacterium striatum. Among 646 RTI episodes, empiric antibiotics were initiated in 440 (68.1%), with 231 (67.5%) deemed appropriate based on culture results.

Despite prolonged admission, nearly a third of the patients harbored only susceptible organisms in their sputum cultures. Empiric treatment was inappropriate in about one third of the RTI episodes. Implementing local antibiograms, applying MDRO risk stratification, and optimizing sputum culture quality may improve empiric treatment accuracy in this vulnerable population.