Treatment, clinical outcomes, and predictors of mortality among a national cohort of hospitalized patients with Stenotrophomonas maltophilia infection.

OBJECTIVES: To analyze treatment, clinical outcomes, and predictors of inpatient mortality in hospitalized patients with Stenotrophomonas maltophilia infection. STUDY DESIGN: Retrospective cohort study. METHODS: We included patients admitted to Veterans Affairs hospitals nationally with S. maltophilia cultures and treatment from 2010 to 2019. We described patient and clinical characteristics, antibiotic treatment, and clinical outcomes. Univariate and multivariable logistic regression were used to evaluate predictors of inpatient mortality. RESULTS: We identified 3891 hospitalized patients treated for an S. maltophilia infection, of which 13.7% died during admission. The most common antibiotic agents were piperacillin/tazobactam (39.7%), sulfamethoxazole/trimethoprim (23.3%), and levofloxacin (23.2%). Combination therapy was used in 16.6% of patients. Independent predictors of inpatient mortality identified in multivariable analysis included the following: presence of current acute respiratory failure (adjusted odds ratio [aOR] 4.74, 95% confidence interval [CI] 3.63-6.19), shock (aOR 3.00, 95% CI 2.31-3.90), acute renal failure (aOR 2.06, 95% CI 1.64-2.60), and septicemia (aOR 1.90, 95% CI 1.49-2.42), age 65 years and older (aOR 2.05, 95% CI 1.07-3.94, reference age 18-49 years), hospital-acquired infection (aOR 1.87, 95% CI 1.48-2.37), Black (aOR 1.58, 95% CI 1.21-2.06) and other races (aOR 1.65, 95% CI 1.41-2.41, reference White), liver disease (aOR 1.51, 95% CI 1.02-2.22), and median Charlson comorbidity score or higher (aOR 1.36, 95% CI 1.08-1.71, reference less than median). Clinical outcomes were similar between patients infected with sulfamethoxazole/trimethoprim-resistant, levofloxacin-resistant, and multidrug-resistant S. maltophilia strains compared to non-resistant strains. CONCLUSIONS: In our national cohort of hospitalized patients with S. maltophilia infection, 13.7% of patients died during admission and several predictors of inpatient mortality were identified. Predictors related to the severity of infection were among the strongest identified. It is important that in severely ill patients presenting to the hospital, S. maltophilia be considered as a cause.

Inhibition of bacterial growth and biofilm production by constituents from Hypericum spp.

Biofilm embedded bacterial pathogens such as Staphylococcus spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii are difficult to eradicate and are major sources of bacterial infections. New drugs are needed to combat these pathogens. Hypericum is a plant genus that contains species known to have antimicrobial properties. However, the specific constituents responsible for the antimicrobial properties are not entirely known, nor have most compounds been tested as inhibitors of biofilm development. The investigation presented here tested seven secondary metabolites isolated from the species Hypericum densiflorum, Hypericum ellipticum, Hypericum prolificum, and Hypericum punctatum as inhibitors of bacterial growth and biofilm production. Assays were conducted against Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Five of the seven compounds demonstrated growth inhibition against the Gram-positive bacteria with minimum inhibitory concentrations (MIC) ranging from 1.95 µg/mL to 7.81 µg/mL. Four of the secondary metabolites inhibited biofilm production by certain Gram-positive strains at sub-MIC concentrations.