title: Surgical site infection in critically ill patients with secondary and tertiary peritonitis: epidemiology, microbiology and influence in outcomes.
abstract: BACKGROUND
  Surgical site infection (SSI) remains a significant problem in the postoperative period that can negatively affect clinical outcomes. Microbiology findings are typically similar to other nosocomial infections, with differences dependent on microbiology selection due to antibiotic pressure or the resident flora. However, this is poorly understood in the critical care setting. We therefore aimed to assess the incidence, epidemiology and microbiology of SSI and its association with outcomes in patients with severe peritonitis in the intensive care unit (ICU).
  
  
  METHODS
  We prospectively studied 305 consecutive patients admitted to our surgical ICU from 2010 to 2014 with a diagnosis of secondary or tertiary peritonitis. We collected the following data: SSI diagnosis, demographics, Acute Physiology and Chronic Health Evaluation (APACHE) II score, Simplified Acute Physiology Score (SAPS) II score, type of surgery, microbiology, antibiotic treatment and outcomes. Microbiological sampling was done by means of swabs.
  
  
  RESULTS
  We identified 269 episodes of SSI in 162 patients (53.1%) aged 64.4 ± 14.3 years, of which 200 episodes occurred in men (64.6%). The mean APACHE II and SAPS II scores were 19.7 ± 7.8 and 36.5 ± 16.1 respectively. The mean ICU and hospital stays were 19.8 ± 24.8 and 21.7 ± 30 days respectively. Pseudomonas spp. (n = 52, 19.3%), Escherichia coli (n = 55, 20.4%) and Candida spp. (n = 46, 17.1%) were the most frequently isolated microorganisms, but gram-positive cocci (n = 80, 29.7%) were also frequent. Microorganisms isolated from SSIs were associated with a higher incidence of antibiotic resistance (64.9%) in ICU patients, but not with higher in-hospital mortality. However, patients who suffered from SSI had longer ICU admissions (odds ratio = 1.024, 95% confidence interval 1.010-1.039, P = 0.001).
  
  
  CONCLUSIONS
  The incidence of SSI in secondary or tertiary peritonitis requiring ICU admission is very high. Physicians may consider antibiotic-resistant pathogens, gram-positive cocci and fungi when choosing empiric antibiotic treatment for SSI, although more studies are needed to confirm our results due to the inherent limitations of the microbiological sampling with swabs performed in our research. The presence of SSI may be associated with prolonged ICU stays, but without any influence on overall mortality.
authors.affiliation: Intensive Care Department, Hospital Universitari de Bellvitge, IDIBELL (Institut d'Investigació Biomèdica Bellvitge; Biomedical Investigation Institute of Bellvitge), C/Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Barcelona, Spain. jballus@bellvitgehospital.cat.
authors.forename: Josep
authors.initials: J
authors.lastname: Ballus
authors.affiliation: Intensive Care Department, Hospital Universitari de Bellvitge, IDIBELL (Institut d'Investigació Biomèdica Bellvitge; Biomedical Investigation Institute of Bellvitge), C/Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Barcelona, Spain. juancarloslopezde@hotmail.com.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Lopez-Delgado
authors.affiliation: Intensive Care Department, Hospital Universitari de Bellvitge, IDIBELL (Institut d'Investigació Biomèdica Bellvitge; Biomedical Investigation Institute of Bellvitge), C/Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Barcelona, Spain. jsabater@bellvitgehospital.cat.
authors.forename: Joan
authors.initials: J
authors.lastname: Sabater-Riera
authors.affiliation: Intensive Care Department, Hospital Universitari de Bellvitge, IDIBELL (Institut d'Investigació Biomèdica Bellvitge; Biomedical Investigation Institute of Bellvitge), C/Feixa Llarga s/n, 08907, L'Hospitalet de Llobregat, Barcelona, Spain. josep@bellvitgehospital.cat.
authors.forename: Xose L
authors.initials: XL
authors.lastname: Perez-Fernandez
authors.affiliation: Intensive Care Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. AJBetbese@santpau.cat.|Universitat Autònoma de Barcelona, C/Sant Quintín 89, 08041, Barcelona, Spain. AJBetbese@santpau.cat.
authors.forename: A J
authors.initials: AJ
authors.lastname: Betbese
authors.affiliation: Intensive Care Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. jroncal@xtec.cat.|Universitat Autònoma de Barcelona, C/Sant Quintín 89, 08041, Barcelona, Spain. jroncal@xtec.cat.
authors.forename: J A
authors.initials: JA
authors.lastname: Roncal
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D016638:Critical Illness / Q000453:epidemiology* / Q000628:therapy; D003428:Cross Infection / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units / Q000706:statistics & numerical data; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010538:Peritonitis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology*; D011379:Prognosis; D013530:Surgical Wound Infection / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology*