title: Inclusion of Vancomycin as Part of Broad-Spectrum Coverage Does Not Improve Outcomes in Patients with Intra-Abdominal Infections: A Post Hoc Analysis.
abstract: BACKGROUND
  Management of complicated intra-abdominal infections (cIAIs) includes broad-spectrum antimicrobial coverage and commonly includes vancomycin for the empiric coverage of methicillin-resistant Staphylococcus aureus (MRSA). Ideally, culture-guided de-escalation follows to promote robust antimicrobial stewardship. This study assessed the impact and necessity of vancomycin in cIAI treatment regimens.
  
  
  METHODS
  A post hoc analysis of the Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial was performed. Patients receiving piperacillin-tazobactam (P/T) and/or a carbapenem were included with categorization based on use of vancomycin. Univariate and multivariable analyses evaluated effects of including vancomycin on individual and the composite of undesirable outcomes (recurrent IAI, surgical site infection [SSI], or death).
  
  
  RESULTS
  The study cohort included 344 patients with 110 (32%) patients receiving vancomycin. Isolation of MRSA occurred in only eight (2.3%) patients. Vancomycin use was associated with a similar composite outcome, 29.1%, vs. no vancomycin, 22.2% (p = 0.17). Patients receiving vancomycin had (mean [standard deviation]) higher Acute Physiology and Chronic Health Evaluation II scores (13.1 [6.6] vs. 9.4 [5.7], p < 0.0001), extended length of stay (12.6 [10.2] vs. 8.6 [8.0] d, p < 0.001), and prolonged antibiotic courses (9.1 [8.0] vs. 7.1 [4.9] d, p = 0.02). After risk adjustment in a multivariate model, no significant difference existed for the measured outcomes.
  
  
  CONCLUSIONS
  This post hoc analysis reveals that addition of vancomycin occurred in nearly one third of patients and more often in sicker patients. Despite this selection bias, no appreciable differences in undesired outcomes were demonstrated, suggesting limited utility for adding vancomycin to cIAI treatment regimens.
authors.affiliation: 1 JPS Health Network , Fort Worth, Texas.
authors.forename: James M
authors.initials: JM
authors.lastname: Sanders
authors.affiliation: 1 JPS Health Network , Fort Worth, Texas.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Tessier
authors.affiliation: 2 Departments of Surgery and Public Health Sciences, University of Virginia , Charlottesville, Virginia.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Sawyer
authors.affiliation: 3 Departments of Surgery, Anesthesiology, Critical Care Medicine, and Nursing, The Johns Hopkins University Schools of Medicine and Nursing , Baltimore, Maryland.
authors.forename: Pam A
authors.initials: PA
authors.lastname: Lipsett
authors.affiliation: 4 Department of Surgery, Wake Forest-Baptist Health , Winston-Salem, North Carolina.
authors.forename: Preston R
authors.initials: PR
authors.lastname: Miller
authors.affiliation: 5 Department of Surgery, University of Miami Health System , Miami, Florida.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Namias
authors.affiliation: 6 Department of Trauma, Abrazo West Campus , Goodyear, Arizona.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: O'Neill
authors.affiliation: 7 Department of Surgery, University of Washington , Seattle, Washington.
authors.forename: E P
authors.initials: EP
authors.lastname: Dellinger
authors.affiliation: 8 Department of Surgery, University of California-San Diego , San Diego, California.
authors.forename: Raul
authors.initials: R
authors.lastname: Coimbra
authors.affiliation: 9 Department of Surgery, University of Virginia , Charlottesville, Virginia.
authors.forename: Chris A
authors.initials: CA
authors.lastname: Guidry
authors.affiliation: 10 Department of Surgery, University of Washington , Seattle, Washington.
authors.forename: Joseph
authors.initials: J
authors.lastname: Cuschieri
authors.affiliation: 11 Department of Surgery, University of Minnesota , Minneapolis, Minnesota.
authors.forename: Kaysie L
authors.initials: KL
authors.lastname: Banton
authors.affiliation: 12 Department of Surgery, Beth Israel Deaconess-Harvard Medical School , Boston, Massachusetts.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Cook
authors.affiliation: 1 JPS Health Network , Fort Worth, Texas.
authors.forename: Billy J
authors.initials: BJ
authors.lastname: Moore
authors.affiliation: 1 JPS Health Network , Fort Worth, Texas.
authors.forename: Therese M
authors.initials: TM
authors.lastname: Duane
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D015897:Comorbidity; D005260:Female; D006801:Humans; D059413:Intraabdominal Infections / Q000188:drug therapy* / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000453:epidemiology* / Q000401:mortality; D016896:Treatment Outcome; D014640:Vancomycin / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin