Influenza Vaccine Effectiveness Against Antigenically Drifted Influenza Higher Than Expected in Hospitalized Adults: 2014-2015.

BACKGROUND: The 2014-2015 influenza season was severe, with circulating influenza A (H3N2) viruses that were antigenically drifted from the vaccine virus. Reported vaccine effectiveness (VE) estimates from ambulatory care settings were markedly decreased. METHODS: Adults, hospitalized at 2 hospitals in southeast Michigan for acute respiratory illnesses, defined by admission diagnoses, of ≤10 days duration were prospectively enrolled. Throat and nasal swab specimens were collected, combined, and tested for influenza by real-time reverse transcription polymerase chain reaction. VE was estimated by comparing the vaccination status of those testing positive for influenza with those testing negative in logistic regression models adjusted for age, sex, hospital, calendar time, time from illness onset to specimen collection, frailty score, and Charlson comorbidity index (CCI). RESULTS: Among 624 patients included in the analysis, 421 (68%) were vaccinated, 337 (54%) were female, 220 (35%) were age ≥65 years, and 92% had CCI > 0, indicating ≥1 comorbid conditions. Ninety-eight (16%) patients tested positive for influenza A (H3N2); among 60 (61%) A (H3N2) viruses tested by pyrosequencing, 53 (88%) belonged to the drifted 3C.2a genetic group. Adjusted VE was 43% (95% confidence interval [CI], 4-67) against influenza A (H3N2); 40% (95% CI, -13 to 68) for those <65 years, and 48% (95% CI, -33 to 80) for those ≥65 years. Sensitivity analyses largely supported these estimates. CONCLUSIONS: VE estimates appeared higher than reports from similar studies in ambulatory care settings, suggesting that the 2014-2015 vaccine may have been more effective in preventing severe illness requiring hospitalization.

Characterization of vancomycin-resistant Enterococcus faecium isolated from swine in three Michigan counties.

Vancomycin-resistant enterococci are a major cause of nosocomial infections but are rarely found in humans in the community and have not been identified in food animals in the United States. We evaluated a total of 360 fecal specimens from humans and their animals being raised for exhibit at three county fairs in Michigan. Fecal samples from 158 humans, 55 swine, 50 cattle, 25 horses, 57 sheep, 14 goats, and 1 llama were obtained and plated onto Enterococcosel agar containing 16 µg/ml of vancomycin. Vancomycin-resistant Enterococcus faecium (VREF) was isolated from six pigs but not from humans or any animal other than pigs. All six VREF isolates had a MIC to vancomycin of ≥256 µg/ml and contained the vanA gene. Pulsed-field gel electrophoresis (PFGE) patterns of the six VREF isolates were ≥80% similar. Multilocus sequence typing (MLST) revealed sequence type 5 (ST5) (n = 2), ST6 (n = 3), and ST185 (n = 1), which are E. faecium sequence types belonging to clonal complex 5 (CC5). These findings show the dissemination of VREF strains among pigs in three Michigan counties. This is the first report of VRE found in food animals in the United States.

Clinical and economic outcomes in patients with community-acquired Staphylococcus aureus pneumonia.

BACKGROUND: While the clinical and economic consequences of S. aureus pneumonia in healthcare settings have been well documented, much less is known about community-acquired S. aureus pneumonia (CAP). METHODS: We retrospectively identified all patients admitted to a large US urban teaching hospital between January 2005 and May 2008 with pneumonia and positive blood or respiratory cultures for S. aureus within 48 hours of admission. Patients with suspected healthcare-associated pneumonia (HCAP) were excluded from the study sample, using established criteria (eg, recent hospitalization, admission from nursing home, hemodialysis). Patients were designated as having methicillin-resistant (MRSA) or methicillin-susceptible (MSSA) CAP based on initial S. aureus isolates. Initial therapy was designated "appropriate" vs. "inappropriate" based on expected susceptibility of the organism to the regimen received. RESULTS: We identified a total of 128 CAP patients with S. aureus isolates; mean (standard deviation [SD]) age was 60 (17) years. A total of 55 patients (43%) had initial cultures positive for MRSA. Patients with MRSA CAP were more likely to receive inappropriate initial therapy (24 [44%] vs. 13 [18%] for MSSA; P = 0.002). Approximately 25% of all patients underwent surgery for pneumonia, 69% received mechanical ventilation, 79% were admitted to intensive care unit (ICU), and 24% died in hospital. Mean (SD) length of stay was 17.0 (15.7) days, and total hospital charges averaged $127,922 ($154,605) per patient; there were no significant differences between patients with MRSA vs. MSSA CAP. CONCLUSION: Outcomes are poor, hospital stays are long, and costs of care are high in patients with S. aureus CAP, and do not differ between those with MRSA vs. MSSA.

Gram-negative endocarditis.

Aerobic gram-negative bacilli are rare causes of endocarditis. The epidemiology and risk factors for developing gram-negative endocarditis are evolving. New pathogens, some of which are multidrug resistant, are emerging. The role of nosocomial infections, particularly central venous catheter infections, is increasing. Medical and surgical outcomes appear to be improving with more effective antimicrobial therapy and aggressive surgical management.