title: Impact of antibacterials on subsequent resistance and clinical outcomes in adult patients with viral pneumonia: an opportunity for stewardship.
abstract: BACKGROUND
  Respiratory viruses are increasingly recognized as significant etiologies of pneumonia among hospitalized patients. Advanced technologies using multiplex molecular assays and polymerase-chain reaction increase the ability to identify viral pathogens and may ultimately impact antibacterial use.
  
  
  METHODS
  This was a single-center retrospective cohort study to evaluate the impact of antibacterials in viral pneumonia on clinical outcomes and subsequent multidrug-resistant organism (MDRO) infections/colonization. Patients admitted from March 2013 to November 2014 with positive respiratory viral panels (RVP) and radiographic findings of pneumonia were included. Patients transferred from an outside hospital or not still hospitalized 72 hours after the RVP report date were excluded. Patients were categorized based on exposure to systemic antibacterials: less than 3 days representing short-course therapy and 3 to 10 days being long-course therapy.
  
  
  RESULTS
  A total of 174 patients (long-course, n = 67; short-course, n = 28; mixed bacterial-viral infection, n = 79) were included with most being immunocompromised (56.3 %) with active malignancy the primary etiology (69.4 %). Rhinovirus/Enterovirus (23 %), Influenza (19 %), and Parainfluenza (15.5 %) were the viruses most commonly identified. A total of 13 different systemic antibacterials were used as empiric therapy in the 95 patients with pure viral infection for a total of 466 days-of-therapy. Vancomycin (50.7 %), cefepime (40.3 %), azithromycin (40.3 %), meropenem (23.9 %), and linezolid (20.9 %) were most frequently used. In-hospital mortality did not differ between patients with viral pneumonia in the short-course and long-course groups. Subsequent infection/colonization with a MDRO was more frequent in the long-course group compared to the short-course group (53.2 vs 21.1 %; P = 0.027).
  
  
  CONCLUSIONS
  This study found that long-course antibacterial use in the setting of viral pneumonia had no impact on clinical outcomes but increased the incidence of subsequent MDRO infection/colonization.
authors.affiliation: Pharmacy Department, Barnes-Jewish Hospital, One Barnes Jewish Hospital Plaza, St. Louis, MO, 63110, USA. MatthewCrotty@MHD.com.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Crotty
authors.affiliation: St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO, 63110, USA. Shelby.Meyers@stlcop.edu.
authors.forename: Shelby
authors.initials: S
authors.lastname: Meyers
authors.affiliation: Center for Clinical Excellence, BJC Healthcare, 8300 Eager Road, St. Louis, MO, 63144, USA. NBH0155@bjc.org.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hampton
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, 4523 Clayton Avenue, Campus Box 8116, St. Louis, MO, 63110, USA. SLB5658@bjc.org.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Bledsoe
authors.affiliation: Pharmacy Department, Barnes-Jewish Hospital, One Barnes Jewish Hospital Plaza, St. Louis, MO, 63110, USA. DJR0519@bjc.org.|St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO, 63110, USA. DJR0519@bjc.org.
authors.forename: David J
authors.initials: DJ
authors.lastname: Ritchie
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, 4523 Clayton Avenue, Campus Box 8116, St. Louis, MO, 63110, USA. Buller@kids.wustl.edu.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Buller
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, 4523 Clayton Avenue, Campus Box 8116, St. Louis, MO, 63110, USA. Storch_G@kids.wustl.edu.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Storch
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, 4523 Clayton Avenue, Campus Box 8052, St. Louis, MO, 63110, USA. MKollef@DOM.wustl.edu.
authors.forename: Marin H
authors.initials: MH
authors.lastname: Kollef
authors.affiliation: St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO, 63110, USA. scott.micek@stlcop.edu.
authors.forename: Scott T
authors.initials: ST
authors.lastname: Micek
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use*; D060085:Coinfection / Q000188:drug therapy; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D024921:Drug Resistance, Multiple, Viral / Q000187:drug effects; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000150:complications / Q000188:drug therapy; D011024:Pneumonia, Viral / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality / Q000821:virology; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents