Impact of BAL in the management of pneumonia with treatment failure - Positivity of BAL culture under antibiotic therapy

Background: Pneumonia is responsible for 50% of antibiotics prescribed in I CUs. Treatment failure, ie, absence of improvement or clinical deterioratio n under antibiotic therapy, presents a dilemma to physicians. BAL is an inv asive method validated for etiologic diagnosis in pneumonia. Study objective: To evaluate in ICU patients the impact of BAL in the etiol ogic diagnosis, treatment, and outcome of pneumonia with treatment failure. Design: Prospective clinical study. Setting: Nonsurgical, medical ICU of a university hospital in Brazil. Patients and participants: Sixty-two episodes of pneumonia treated for at l east 72 h without clinical improvement in 53 patients hospitalized for dive rse clinical emergencies. Mean duration of hospitalization was 14.2 days. M ean duration of precious antibiotic therapy was 11.4 days. Interventions: Bronchoscopy and BAL were performed in each episode. BAL flu id was cultivated for aerobic and anaerobic bacteria; the cutoff considered positive was 10(4) cfu/mL; 10(3) cfu/ml was also analyzed if under treatme nt. Pneumocystis carinii, fungi, Legionella spp, and Mycobacterium spp were also researched. Measurements and results: Fifty-eight of 62 BAL were performed under antibi otics. The results showed positivity in 45 of 62 (72.6%); 42 of the 45 posi tive episodes (93.3%) had > 10(4) cfu/ml. The three cases with between 103 and 104 cfu/ml were considered positive and were treated according to BAL c ultures. The main agents were Acinetobacter baumannii (37.1%), Pseudomonas aeruginosa (17.7%), and methicillin-resistant Staphylococcus aureus (MRSA; 16.1%); 46.7% of the episodes (21 of 45) were polymicrobial. BAL results di rected a change of therapy in 34 episodes (54.8%). Overall mortality was 43 .5%. There was no difference in mortality among positives, negatives, and p atients who changed therapy guided by BAL culture. Conclusions: (1) BAL fluid examination was positive in 45 of 62 episodes (7 2.6%), with 58 of 62 BAL performed under antibiotics. This suggests that BA L may be a sensitive diagnostic method for treatment failures of clinically diagnosed pneumonias, even if performed under antibiotics; (2) the main pa thogens in our study were A baumannii, P aeruginosa, and MRSA, and approxim ately 45% of infections were polymicrobial; (3) BAL culture results directe d a change of therapy in 75.6% of positive episodes (34 of 45) and in 54.8% of all episodes of treatment failure (34 of 62); and (4) there was no diff erence in mortality among positives, negatives, and patients who changed th erapy guided by BAL culture.