To determine the relation between prior exposure to specific antimicrobials and acquisition of gram-negative bacilli resistant to multiple ß-lactam and aminoglycoside antibiotics among long-term-care patients.

Case-control study. Cases were patients from whom multiply resistant Enterobacteriaceae or Pseudomonas aeruginosa were isolated; controls were patients from whom nonresistant bacteria of the same species were isolated. Prospectively defined risk factors included underlying illness, activity level, presence of decu-bitus ulcers, presence of indwelling devices, and prior exposure to specific antimicrobial agents. Resistant and control isolates of P aeruginosa were compared using pulsed-field gel electrophoresis (PFGE) of genomic DNA after digestion with XbaI.

390-bed long-term Veterans' Affairs facility.

We identified 35 patients with multiply resistant Enterobacteriaceae and 24 patients with multiply resistant P aeruginosa. Of the resistant Enterobacteriaceae, 87% of isolates were resistant to piperacillin, 55% to ceftazidime, and 90% to gentamicin. Acquisition of multiply resistant Enterobacteriaceae was associated with presence of decubitus ulcers (odds ratio [OR], 12.2; 95% confidence interval [CI95], 3.3-44.2; P=.0002) and prior receipt of ampicillm (OR, 13.7; CI95, 2.2-84; P=.005). Of resistant isolates of P aeruginosa, 88% were resistant to piperacillin, 25% to ceftazidime, 42% to imipenem, and 67% to ciprofloxacin. Isolation of a multiply resistant P aeruginosa was associated with total days of antimicrobial exposure (OR, 1.07; CI95, 1.01-1.12; P=.011) and not with prior receipt of any individual agent. Eleven multiply resistant isolates shared a common PFGE pattern.

In our long-term-care facility, acquisition of multiply resistant Enterobacteriaceae was associated with the presence of decubitus ulcers and prior exposure to ampicillin. Acquisition of resistant P aeruginosa was associated with total antibiotic exposure. Molecular typing of P aeruginosa isolates implicated patient-to-patient transmission of a limited number of resistant strains.

To detect respiratory adverse reac¬tions potentially related to receipt of peripheral parenteral nutrition (PPN) in hospitalized patients and to determine risk factors for their occurrence.

Retrospective cohort study.

Federal tertiary-care hospital.

Medical and pharmacy records of all patients who received PPN from October 1992 to February 1994 were abstracted for demographics, diagnoses, medications received, indications for and formulation of PPN, and severity of illness as measured by Acute Physiology and Chronic Health Evaluation II scores.

A case-patient was defined as any patient who, while receiving PPN, had unexplained chest pain, dyspnea, cardiopulmonary arrest, or new interstitial infiltrates on chest radiograph. Patients who received PPN in which FreAmine was the amino acid source were more likely than those who received PPN made with Travasol to meet the case definition (5/11 vs 0/39; relative risk, >18; 95% confidence interval, 3.3->136; P<.001).

A change in the amino acid source of a PPN admixture was associated with respiratory adverse events that ranged from interstitial infiltrates to sudden death. These events apparently resulted from the infusion of a calcium phosphate precipitate in an opaque admixture. Each new PPN admixture should be tested for stability before clinical use and infused into patients through an appropriate filter.

To determine the feasibility of stan¬dardized surveillance of nosocomial infections (NI) in The Netherlands, using local data on patients with NI collected by infection control practitioners (ICPs) and denominator data on all patients under surveillance obtained from the Dutch National Medical Registry (LMR).

A prospective, multicenter study.

Eight hospitals in the Utrecht region, and the National Institute of Public Health and the Environment.

ICPs traced NI in gynecological and orthopedic patients for 9 to 16 months. Denominator data on all patients under surveillance were obtained from the LMR

Data from 8,922 patients were collected; the ICPs registered 470 patients with 526 N1. Overall, the NI incidence was 5.9 per 100 patients, or 6.3 per 1,000 patient days. Urinary tract infections (UTI) were most frequent (3.3%), followed by surgical-wound infections (SWI; 2.0%) and bloodborne infections (0.12%). The incidence of both SWI and UTI differed markedly between hospitals, only partially on account of differences in patient mix (age, type of operations), antibiotic prophylaxis, and intensity of tracing methods for NI. Delay in the availability of denominator data hampered the timely feedback of incidence figures.

Surveillance of NI in a network of sentinel hospitals offered valuable information on the occurrence of NI and on factors influencing the incidence of NI. It revealed situations in which both NI surveillance and infection control methods in individual hospitals should be improved. Obtaining denominator data on all patients from electronically registered patient discharge data greatly reduces the workload of ICPs and enables surveillance on all types of NI (all body sites and all pathogens). For timely feedback, numerator and denominator data within hospitals must be linked.

To identify risk factors predictive of nosocomial infection in an intensive-care unit (ICU) and to identify patients with a higher risk of nosocomial infection using a predictive model of nosocomial infection in our ICU.

Prospective study; daily concurrent surveillance of intensive-care-unit patients.

All patients admitted for at least 24 hours to the ICU of a tertiary-level hospital from February to November 1994 were followed daily.

Variables measuring extrinsic and intrinsic risk factors for nosocomial infection were collected on each patient during their ICU stay, and the Cox Proportional Hazards multivariable technique was used to identify the variables significantly associated with infection.

The population studied consisted of 944 patients. The main risk factors identified were intrinsic; the significant extrinsic risk ofactors identified were head of the bed in a horizontal (<30°) position (this variable presented the highest increase of the infection hazard ratio) and the use of sedative medication. Patients presenting the highest risk scores using the predictive model are those with the highest risk of nosocomial infection.

The important preventive measures derived from our results are that underlying conditions suffered by the patient at the ICU admission should be corrected promptly, the depression of the patient's level of consciousness with sedatives should be monitored carefully, and the horizontal position of the head of the bed should be avoided totally. Patients with a high risk of infection can be the target of special preventive measures.