title: [Incidence of nosocomial surgical-site infections. Application of National Nosocomial Infections Surveillance System (NNIS) index and description of clinical and biochemical features from patients undergoing first-time ventriculoperitoneal shunt].
abstract: OBJECTIVE
  We undertook this study to determine the incidence of nosocomial surgical-site infections, apply the National Nosocomial Infections Surveillance (NNIS) index, and describe the clinical and biochemical characteristics of patients prior to a first-time ventriculoperitoneal shunt (VPS).
  
  
  METHODS
  We conducted a cohort study for 1 year with patients aged 18 years or older who underwent VPS. Patients were followed up for 30 days to identify the presence of an infection. Infection diagnosis was made according to the criteria established by the Centers for Disease Control (Atlanta, GA). A questionnaire was developed to obtain the data regarding the factors contained in the NNIS and the clinical and biochemical characteristics prior to surgery.
  
  
  RESULTS
  The annual incidence of nosocomial surgical-site infections was 12.3% (9/73). Distribution of factors according to the NNIS index was as follows: 55% without any factor, 38% with one factor, 7% with two factors, and no patients with three factors. ASA RR = 2.0, 95% CI 0.4-11.4, wound type RR = 5.1, 95% CI 0.5-48.9 and surgical time RR = 0.6, 95% CI 0.1-4.2. No differences were found in the frequency of concomitant diseases.
  
  
  CONCLUSIONS
  Even though the clinical and biochemical characteristics of patients who underwent first-time VPS were normal and no associated NNIS factors were identified, 12.3% of the patients developed a nosocomial surgical-site infection. These results suggest the existence of factors other than those contained in the NNIS, which are possibly extrinsic to the individual and may influence the development of infections.
authors.affiliation: Unidad de Investigación en Epidemiología Hospitalaria, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México, D.F., Mexico. rosalinda.arenas@yahoo.com.mx
authors.forename: Rosalinda
authors.initials: R
authors.lastname: Sánchez-Arenas
authors.forename: Blanca Elsa
authors.initials: BE
authors.lastname: Rivera-García
authors.forename: Israel
authors.initials: I
authors.lastname: Grijalva-Otero
authors.forename: Teresa
authors.initials: T
authors.lastname: Juárez-Cedillo
authors.forename: Luis
authors.initials: L
authors.lastname: Toca-Porras
authors.forename: María
authors.initials: M
authors.lastname: Del Carmen Martínez-García
mesh_terms: D015331:Cohort Studies; D003428:Cross Infection / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000453:epidemiology*; D017287:Ventriculoperitoneal Shunt