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Background/purpose The impact of bacteremia due to the resistance of Stenotrophomonas maltophilia to trimethoprim–sulfamethoxazole (TMP–SXT) is uncertain. This study compared the clinical characteristics and outcomes of patients with TMP–SXT-susceptible (TSSSM) and TMP–SXT-resistant S. maltophilia (TSRSM) monomicrobial bacteremia. Methods The medical records of adult patients with TSSSM and TSRSM monomicrobial bacteremia from January 2004 to December 2013 were reviewed and classified into two groups, namely, TSSSM and TSRSM. Results There were 184 patients with monomicrobial S. maltophilia bacteremia. The mean age was 68.3 years. Most patients were males (72.8%), had high Charlson Comorbidity Index scores, previously prescribed antimicrobial agents, and indwelling medical devices. The 14-day and in-hospital mortality rates were 23.9% and 47.2%, respectively. There were 128 patients (69.6%) with TSSSM and 56 (30.4%) with TSRSM. The incidence of TSSSM bacteremia increased during the study period. The TSSSM and TSRSM groups had similar demographic and clinical characteristics and no significant differences in 14-day and in-hospital mortality (24.2% vs. 23.2%, p = 0.833; 50.0% vs. 41.1%, p = 0.264, respectively). Patients with TSSSM bacteremia had an increased risk of septic shock ( p = 0.044) and neutropenia ( p = 0.028) at bacteremia onset. Logistic regression analysis indicated that acquisition of TMP–SXT resistance was an independent risk factor for prolonged hospitalization ( p = 0.018) and catheter-related S. maltophilia bacteremia was inversely associated with prolonged hospitalization after bacteremia ( p = 0.032). Conclusion There were no significant differences in mortality for patients with TSSSM and TSRSM bacteremia, but patients with TSRSM bacteremia were associated with prolonged hospitalization after bacteremia onset.

Background Acinetobacter baumannii hospital-acquired pneumonia (HAP) is associated with a high mortality worldwide. Non-ventilated patients with HAP (NVHAP) caused by nosocomial pathogens are reported to have a more favorable outcome than those with ventilator-associated pneumonia (VAP). The current study was designed to determine whether bacteremic patients with A. baumannii NVHAP also have a lower mortality than those receiving assisted ventilation. Methods This retrospective 10-year study was conducted at a 2900-bed teaching hospital located in Northern Taiwan. The population consisted of 144 patients with A. baumannii bacteremia and HAP. Of these 96 had VAP and 48 had NVHAP. Charts were reviewed for demographic characteristics, comorbidities, clinical manifestations, antimicrobial susceptibility, and 14-day mortality. Clonal relationships were determined by molecular typing. Results There were no significant differences between the two groups in comorbidities (Charlson scores). Patients with NVHAP were more likely to have developed bacteremia earlier, outside the ICU and undergone fewer invasive procedures. They had significantly lower APACHE II scores, fewer bilateral pneumonias and lower rates of antimicrobial resistance. No specific clones were identified in either group. The unadjusted (crude) 14-day mortality rates were not significantly different between the groups (NVHAP 43.8% vs. VAP 31.3%, p = 0.196). The adjusted 14-day mortality risk was significantly lower in ventilator-assisted patients (odds ratio = 0.201; 95% confidence interval = 0.075-0.538; p = 0.001). Conclusions Patients with bacteremic NVHAP and VAP caused by A. baumannii had similar crude mortality rates, but on logistic regression analysis those receiving ventilator assistance had a significantly lower mortality. This may have been due to better airway protection, more intensive monitoring with earlier diagnosis and treatment in patients with VAP, greater innate susceptibility to infection in those with NVHAP and differences in the virulence of A. baumannii.

Background It is unknown whether there are differences between bacteremia caused by carbapenem resistant Acinetobacter baumannii (CRAB) and carbapenem resistant Acinetobacter nosocomialis (CRAN). This study aims to investigate the differences, especially in clinical outcomes, between patients with bacteremia caused by CRAB or CRAN. Methods This is a 9-year retrospective study comparing the clinical manifestations, antimicrobial susceptibilities, and clinical outcomes of 71 patients with CRAB bacteremia and 64 patients with CRAN bacteremia. Results Patients with CRAB were more likely to have hematologic malignancies and presented with more shock episodes than those with CRAN. CRAB isolates were more resistant to various classes of antimicrobials except colistin, and therefore the patients with CRAB bacteremia were more likely to receive inappropriate antimicrobial therapies. The 14-day mortality was significantly higher in patients with CRAB (40.8% vs. 14.1%; p = 0.001), and in this study, acquisition of CRAB was identified as an independent risk factor for mortality (odds ratio = 4.003; 95% confidence interval = 1.566-10.231; p = 0.004). Conclusions CRAB and CRAN bacteremia are different in clinical characteristics, antimicrobial susceptibilities, and mortality rates. Genomic species identification should be performed in the study of carbapenem resistant Acinetobacters to better delineate the role of different species.