Evaluation of two retrospective active surveillance methods for the detection of nosocomial infection in surgical patients.

OBJECTIVE: To compare the sensitivity and specificity of two retrospective active surveillance methods based on review of the medical record and review of the discharge form in identfying nosocomial infection, taking the prospective surveillance method as the reference standard. DESIGN: Blind comparison of three active nosocomial infection surveillance methods. SETTING: Department of General Surgery of a tertiary-care hospital with a referral population of 266,000 people. METHODS: All operated patients admitted to the Department of Surgery for more than 24 hours and discharged from January 1, 1994, to December 31, 1994, were included. Prospective surveillance consisted of daily review of the patient's record during hospitalization. Retrospective surveillance consisted of review of the medical record and the discharge form. Sensitivity and specificity of both retrospective methods were calculated. RESULTS: Of the 1,514 patients included in the study, 1,476 (97.5%) were reviewed by means of the retrospective surveillance system. A total of 20, 8, and 4 hours per week was needed for the active prospective system, review of the medical record, and review of the hospital discharge form, respectively. The documented cumulative incidence of nosocomial infection was 21.8% for the prospective system, 19.6% for review of the medical record, and 12.6% for review of the discharge form. The overall sensitivity of review of the medical record was 88% and of the discharge form 56%, with a specificity of 99%. For review of the medical record, the highest sensitivity was 93%, for urinary tract infections; for review of the discharge form, the highest was 57%, for surgical-wound infection. CONCLUSIONS: The retrospective method of review of the medical record was the most efficient active surveillance strategy in detecting nosocomial infection in surgical patients.

Isolation of Neisseria meningitidis strains with increase of penicillin minimal inhibitory concentrations.

We report the isolation and characterization of ten strains showing an increase in the minimal inhibitory concentrations to penicillin (MICs greater than 0.1 microgram/ml), and describe the epidemiological, clinical and microbiological features. The susceptibility of 3432 meningococcal strains isolated from patients in the recent epidemic wave (1978-86) in Spain, to several antimicrobial agents used in the treatment and chemoprophylaxis of meningococcal infection has been tested. Most were resistant to sulphadiazine but sensitive to other antibiotics. The possible existence of a new pattern of behaviour of meningococcal to penicillin is discussed.