To characterize the epidemiological relationships among Stenotrophomonas maltophilia isolates in the neonatology unit of our institution over a 4-month period in which an increased number of isolates was observed.

The neonatology ward in a 2,000-bed university hospital in Madrid, Spain.

A retrospective molecular epidemiological analysis using three different typing methods, arbitrarily primed polymerase chain reaction (PCR), pulsed-field gel electrophoresis, and enterobacterial repetitive intergenic consensus-PCR, was performed with 11 isolates obtained from seven neonates over a 4-month period. Presumed unrelated isolates also were included as controls. A similarity dendrogram was obtained, to analyze the genetic relatedness among the isolates.

All isolates from the neonates, except one, showed a remarkably high homology among their typing patterns for the three methods assayed and clustered in the relatedness dendrogram at 96% similarity. The unrelated strains selected as controls were unclustered. The index case was considered to be a newborn who had an S maltophilia isolate from a culture drawn on the day of admission to the neonatology unit and which was included in the clustered similarity group.

Such a high genetic similarity among the isolates, together with the presence of an index case who had been colonized or infected by S maltophilia before arrival at our institution, constitutes the first evidence of nosocomial cross-transmission of this microorganism.

To study vancomycin-resistant Enterococcus (VRE) prevalence, risk factors, and clustering among hospital inpatients.

Rectal-swab prevalence culture survey conducted from February 5 to March 22,1996.

The Veterans' Affairs Medical Center, Atlanta, Georgia.

Hospital (medical and surgical) inpatients.

The overall VRE prevalence was 29% (42/147 patients). The VRE prevalence was 52% (38/73 patients) among patients who had received at least one of six specific antimicrobials during the preceding 120 days, compared with only 5% (4/74) among those who had not received the antimicrobials (relative risk, 9.6; P <.001). The longer the period (up to 120 days) during which antimicrobial use was studied, the more closely VRE status was predicted. Among 67 hospital patients in 28 multibed rooms, clustering of VRE among current roommates was not found.

At this hospital with relatively high VRE prevalence, VRE colonization was related to antibiotic use but not to roommate VRE status. In hospitals with a similar VRE epidemiology, obtaining cultures from roommates of VRE-positive patients may not be as efficient a strategy for identifying VRE-colonized patients as obtaining screening cultures from patients who have received antimicrobials.

To determine the prevalence and risk factors for nosocomial infections (NIs) in four Swiss university hospitals.

A 1-week period-prevalence survey conducted in May 1996 in medical, surgical, and intensive-care wards of four Swiss university hospitals (900-1,500 beds). Centers for Disease Control and Prevention definitions were used, except that asymptomatic bacteriuria was not categorized as NI. Study variables included patient demographics, primary diagnosis, comorbidities, exposure to medical and surgical risk factors, and use of antimicrobials. Risk factors for NIs were determined using logistic regression with adjustment for length of hospital stay, study center, device use, and patients' comorbidities.

176 NI were recorded in 156 of 1,349 screened patients (11.6%; interhospital range, 9.8%-13.5%). The most frequent NI was surgical-site infection (53; 30%), followed by urinary tract infection (39; 22%), lower respiratory tract infection (27; 15%), and bloodstream infection (23; 13%). Prevalence of NI was higher in critical-care units (25%) than in medical (9%) and surgical wards (12%). Overall, 65% of NIs were culture-proven; the leading pathogens were Enterobacteriaceae (44; 28%), Staphylococcus aureus (20; 13%), Pseudomonas aeruginosa (17; 11%), and Candida species (16; 10%). Independent risk factors for NI were central venous catheter (CVC) use (odds ratio [OR], 3.35; 95% confidence interval [CI95], 2.91-3.80), admission to intensive care (OR, 1.75; CI95, 1.30-2.21), emergency admission (OR, 1.57; CI95, 1.15-2.00), impaired functional status (Karnofsky index 1-4: OR, 2.56; CI95, 1.95-3.17), and McCabe classification of ultimately fatal (OR, 2.50; CI95, 2.04-2.96) or rapidly fatal (OR 2.25; CI95,1.52-2.98) underlying condition.

According to the results of this survey, NIs are frequent in Swiss university hospitals. This investigation confirms the importance of CVCs as a major risk factor for NI. Patient comorbidities must be taken into account to adjust for case mix in any study comparing interhospital or intrahospital infection rates.

To study the incidence of tuberculosis (TB), tuberculin skin testing (TST) practices, and infection control practices at outpatient hemodialysis centers.

Mail surveys performed in December 1994 and 1995.

The numbers of patients with incident active TB during 1994 and 1995, TST policies during 1994, and TB infection control policies in 1994.

All outpatient dialysis centers in New Jersey.

Healthcare workers and patients in dialysis centers in New Jersey.

Of 47 centers, 41 provided information on TST and TB infection control policies and practices. TSTs were performed on newly hired healthcare workers at all 41 centers and on established workers at 39 centers. In contrast, only 1 center reported performing TSTs on hemodialysis patients; 5 other centers reported screening of patients for TB using chest radiographs. Active TB was reported in 3 of 4,550 chronic hemodialysis patients in 1994 (rate, 66/100,000 patient-years) and in 4 of 4,831 patients in 1995 (rate, 83/100,000 patient-years). Both rates were several times higher than the rate in the New Jersey general population during this period (10.7-10.8/100,000).

Although based on small numbers of patients with TB, we found a relatively high incidence of TB among hemodialysis patients in New Jersey. Most centers reported performing TSTs on workers but not on patients. These results suggest the need for improved TB screening and infection control precautions at outpatient dialysis centers.

To describe the investigation and control of transmission of vancomycin-resistant enterococci (VRE) in a residential long-term-care (LTC) setting.

A strain of vancomycin-resistant Enterococcus faecium not previously isolated in Ontario colonized five residents of a 254-bed LTC facility in Toronto. The index case was identified when VRE was isolated from a urine culture taken after admission to a local hospital. Screening of rectal swabs from all 235 residents identified four others who were colonized with the same strain of E faecium.

Colonized residents were cohorted. VRE precautions were established as follows: gown and gloves for resident contact, restriction of contact between colonized and noncolonized residents, no sharing of personal equipment, and daily double-cleaning of residents' rooms and wheelchairs.

Two colonized residents died of causes unrelated to VRE. Although bacitracin therapy (75,000 units four times a day X 14 days) failed to eradicate carriage in two of three surviving residents, both cleared their carriage within 7 weeks. Repeat rectal swabs from 224 residents (91%) 2 months after isolation precautions were discontinued and from 125 residents (51%) 9 months later identified no new cases. Total cost of investigation and control was $12,061 (Canadian).

VRE may be transmitted in LTC facilities, and colonized LTC residents could become important VRE reservoirs. Control of VRE transmission in LTC facilities can be achieved even with limited resources.

To assess the practice of antimicrobial prophylaxis for surgical procedures in eight surgical departments in a 550-bed teaching hospital.

A list of all major procedures performed in our hospital, with recommendations for prophylaxis based upon the literature, has been distributed since 1993 and is updated periodically. The practice of surgical prophylaxis between January 1 and March 31,1996, was examined by assessing four variables: (1) Did the particular procedure justify prophylaxis, and was it provided? (2) Was timing optimal, ie, within 1 hour prior to surgery? (3) Was the appropriate antimicrobial selected? (4) Was duration optimal, ie, ≤24 hours?

During the study period, 2,117 operations were performed, of which 1,631 (77%) were reviewed. Sixty-six percent were clean surgery, 28% clean-contaminated, and 6% contaminated; 72% of procedures were elective, 28% emergencies. Of 1,631 operations requiring prophylaxis, 1,142 (70%) received it, 489 (30%) did not. Of 1,631 patients, 1,392 (85%) received appropriate care: 929 (67%) appropriately received prophylaxis, and 463 (33%) appropriately did not receive prophylaxis. Of 955 patients who received prophylaxis, 26 (3%) did so inappropriately. Of 1,142 patients who should have received prophylaxis, 213 (19%) did not receive it. Female gender, clean surgery, elective operations, and infrequently performed procedures were all significant indicators of inappropriately withheld prophylaxis (P<.001). In addition, the rate of appropriately provided prophylaxis varied between departments from 71% to 97% (P<.001). Assessment of the 929 procedures for which prophylaxis was justified and given revealed that 100% of patients received it on time, the choice of antimicrobial was appropriate in 95% of cases, and duration was ≤24 hours in 91%.

Audits of surgical prophylaxis are expected to detect different errors in different institutions. Conducting audits of surgical prophylaxis probably should be part of the routine activity of infection control teams. Feeding the information back to surgeons could improve adherence to recommended guidelines and might contribute to reduced wound infection rates.

To assess the virucidal activity of three disinfectants (sodium hypochlorite, a phenolic, and a quaternary ammonium compound) in the presence and absence of blood.

Disinfectants at varying concentrations (hypochlorite: 5,000, 500, or 50 ppm; phenolic: 1:10 or 1:128 dilution; quaternary ammonium compound: 1:10 or 1:128 dilution) were added to either saline or whole blood (final concentration, 80% or 20% blood) and mixed. Test organisms included an attenuated vaccine strain of poliovirus type 1 (prototype for relatively resistant hydrophilic viruses) and herpes simplex virus (HSV) type 1 (prototype for relatively susceptible lipophilic viruses). Virus was added to create a viral-blood suspension. Viral survival was tested at room temperature at the following times: 0, 15 seconds, 30 seconds, 1 minute, 2 minutes, 5 minutes, and 10 minutes. A neutralizer stopped the reaction, and virus was assayed using a plaque technique.

In the absence of blood, complete inactivation of HSV was achieved within 30 seconds with 5,000 (1:10 dilution of bleach) and 500 (1:100 dilution of bleach) ppm chlorine, 1:10 and 1:128 diluted phenolic (use dilution), and 1:10 and 1:128 diluted quaternary ammonium compound (use dilution). In the presence of 80% blood, only 5,000 ppm hypochlorite, 1:10 phenolic, and 1:10 or 1:128 quaternary ammonium compound were effective. In the absence of blood, complete inactivation of polio was achieved within 30 seconds by 5,000 and 500 ppm chlorine and 1:10 quaternary ammonium compound. In the presence of 80% blood, no solution tested was capable of completely inactivating poliovirus within 10 minutes.

Our data suggest that, in the absence of visible blood, environmental surfaces may be disinfected with a diluted hypochlorite solution (1:10 or 1:100), a phenolic, or a quaternary ammonium compound. Based on our studies using HSV, which has similar susceptibilities to disinfectants as human immunodeficiency virus (HIV), phenolics at their use dilution and 1:100 diluted hypochlorite are unlikely to inactivate HIV or hepatitis B virus reliably in the presence of blood. Hypochlorite at a final concentration of 5,000 ppm (1:10 dilution) should be used to decontaminate blood spills, but, even after decontamination, care should be used to avoid sharps injuries.

To examine the impact of a new policy to ensure appropriate use of vancomycin in a 461-bed tertiary-care hospital.

We instituted a policy that allowed physicians to prescribe vancomycin but that required them to complete a vancomycin continuation form and document that use conformed to Hospital Infection Control Practices Advisory Committee (HICPAC) guidelines if they wished to continue the drug beyond 72 hours. Vancomycin was stopped automatically at 72 hours if use was not consistent with guidelines, if an infectious diseases consultant did not approve the drug, or if the form was not completed. A pharmacist and infectious diseases specialist monitored use of vancomycin prospectively and interacted with prescribers when indicated. Educational efforts were limited to printing the HICPAC guidelines on the form and providing information about the policy in a newsletter. Patterns of prescribing and the economic impact of the form were evaluated over a 6-month period.

Only 29% to 48% of vancomycin orders initially met HICPAC guidelines, but 77% to 96% of use was appropriate after 72 hours when the form was used. Inappropriate surgical prophylaxis, empirical therapy of intensive-care unit and transplant patients, and therapy for inadequately documented coagulase-negative staphylococcal infections remained problems. Vancomycin use fell from a mean of 136 (±52) g/1,000 patient days in the 12 months before the form to 78 (±22) g/1,000 patient days in the 9 months after institution of the form (P<.05). Net vancomycin acquisition costs and costs of ordering vancomycin serum levels fell by $357 and $19 per 1,000 patient days, respectively (P<.05). This represented annualized saving of approximately $47,000 in drug and monitoring costs. No adverse patient outcomes were seen as a result of the program.

A vancomycin continuation form can decrease inappropriate vancomycin use and may save money. Additional educational efforts may be required to increase compliance with HICPAC guidelines during initial prescribing.

After pertussis was diagnosed in July 1997 in a 55-year-old nurse (case) from a pediatric emergency unit who had a respiratory illness and paroxysmal cough for 5 weeks, an epidemiological investigation was initiated to determine if other healthcare workers (HCWs) from the same unit also had pertussis.

Interviews were conducted to assess symptoms occurring in the previous months. Two sera were collected 2 to 3 months apart for 59 of 61 HCWs of the unit. The IgG response to pertussis toxin was determined using Western blot assay.

Pediatric emergency unit (61 HCWs) of a 2,500-bed university hospital.

There was a total of 10 (5 confirmed and 5 probable) cases of pertussis identified in this outbreak. Nine HCWs (15%) had results suggesting recent or acute pertussis. To avoid transmission to patients and other HCWs, all HCWs with cough were treated for 14 days with erythromycin, and those having acute cough were given a 5-day sick leave. Despite these measures, a new acute pertussis case was identified in a 41-year-old nurse, with a positive culture from nasopharyngeal aspirates. Thus, all HCWs in the unit were prescribed spiramycin for 10 days to prevent any further spread of pertussis.

Pertussis should be considered a threat to HCWs who are in contact with children. For HCWs, diagnosis of pertussis should be made on a clinical basis, giving greater importance to sensitivity of diagnosis criteria, and on early bacterial identification by culture of the organism or by polymerase chain reaction.

In case of pertussis in an HCW, all staff in the unit who have had unprotected and intensive contact with that person should be provided with macrolide treatment to stop any transmission to colleagues and to young patients. Furthermore, the possibility of providing these HCWs with acellular pertussis vaccines warrants further investigation.