CONFERENCE NEWS UPDATE:
4TH DECENNIAL INTERNATIONAL CONFERENCE
ON NOSOCOMIAL AND HEALTHCARE-ASSOCIATED INFECTIONS

ATLANTA--Patient-to-patient transmission of hepatitis C virus was associated with use of multidose saline vials, researchers reported at the 4th Decennial International Conference on Nosocomial and Healthcare-Associated Infections in Atlanta. Other highlights of the meeting included findings of improved handwashing compliance following initiation of a competition among doctors and of a lack of adherence to the recommendation that health care workers be vaccinated against influenza.

INFECTIONS AMONG PATIENTS TREATED AT HOME

People who receive medical care in the home are at risk of acquiring the same infections as those treated in hospitals, according to new findings by Lilia P. Manangan, RN, MPH, and colleagues. Their recent survey showed that one of every six patients receiving home health care during one month in 1999 had infections.

Nurses from 73 Missouri home care agencies completed questionnaires on 5,148 patients. According to the nurses' responses, 793 patients (16%) had infections. The urinary tract was the most common site of infection (27%), followed by the respiratory tract (24%), skin/soft tissue (24%), surgical site (12%), and bloodstream (2%). Of these infections, 41% were community-acquired, 16% were hospital-acquired, and 8% were home care-acquired. The source of the remaining 35% was unknown.

"The use of medical devices, such as urinary and central venous catheters, in the home appears to increase one's risk of acquiring an infection--just as it does when used in the hospital," said Ms. Manangan, an epidemiologist at the Hospital Infections Program of the Centers for Disease Control and Prevention (CDC). In fact, use of a urethral or suprapubic catheter was significantly associated with an increased risk of urinary tract infection; similarly, use of a central venous catheter was significantly associated with an increased risk of bloodstream infection. On the other hand, ventilator use was not associated with an increased risk for respiratory tract infection.

The CDC is striving to further address infections associated with home health care. "We need to extend to home health care delivery the same standards we have applied in the hospital setting," said Julie Gerberding, MD, director of the CDC's Hospital Infections Program. "We have to monitor the frequency of these events and learn how to prevent them," she added.

FEW HEALTH CARE WORKERS ARE VACCINATED AGAINST INFLUENZA

Poor adherence by health care workers to the recommendations for influenza vaccination was found in a recent survey of hospitals participating in the National Surveillance System for Health Care Workers (NaSH). In addition, few of the hospitals reported having policies for surveillance or epidemic control of influenza.

Matthew J. Kuehnert, MD, and colleagues from the CDC surveyed 24,736 health care workers from seven hospitals participating in the NaSH in 1996 and 1997. Overall, 6,903 workers (27.9%) had received their annual influenza vaccine. This percentage ranged from about 20% to 44% among the seven hospitals and was highest among physicians and physician assistants (40%) and lowest among technicians and clerical staff (22%).

In 1999, Dr. Kuehnert and colleagues surveyed 34 hospitals participating in the NaSH to assess institutional practices regarding influenza surveillance. Rapid diagnostic testing was available at 50% of the hospitals; however, only 27% of hospitals routinely conducted exposure investigations when influenza was suspected. The following reasons for not conducting investigations were reported: lack of awareness that influenza was a significant problem, lack of expertise for investigation, lack of requirement for disease reporting, and logistic difficulties, such as lack of time, staff, or resources.

"Additional guidance and improved dissemination of existing information are needed for effective implementation of influenza prevention measures in acute-care facilities," Dr. Kuehnert and colleagues concluded.

HANDWASHING COMPETITION IMPROVES COMPLIANCE

A dramatic improvement in handwashing compliance was found after implementation of a competition among three surgical teams at the Naval Medical Center in San Diego, Calif, reported Jean E. Thompson-Bowers, BSN, CIC, and colleagues.

In December 1998, a nurse secretly counted the number of handwashing episodes per patient contact while physicians made rounds. At that time, the proportion of physicians who washed their hands after contact with each patient ranged from 0% to 16% among three surgical teams. The physicians were then informed of their rates and were told that the competition had begun. By the second audit in March 1999, these rates had dramatically improved (Table 1).

A third audit was completed in August 1999 after new house staff had arrived. These rates showed a decrease in compliance from the previous audit but were still better than the initial observation (range, 37% to 43%).

HEPATITIS C AND SALINE VIALS

Patient-to-patient transmission of hepatitis C virus (HCV) in a Florida hospital appears to be linked to contamination of a multidose saline vial. "The use of single-dose vials or prefilled syringes for saline flushes might further reduce the risk of nosocomial transmission of bloodborne pathogens," reported Gérard Krause, MD, DrMed, and colleagues.

In November 1998, a cluster of patients was diagnosed with HCV infection within eight weeks of being admitted to the same ward of a Miami hospital. The researchers retrospectively studied 24 of the 41 patients hospitalized in this ward from November 11 to 19, 1998. They interviewed the patients, abstracted records, tested blood samples for HCV antibodies, and genotyped and sequenced HCV RNA-positive samples.

Five of the 24 patients were infected with HCV genotype 1b. Three acute cases, one chronic case, and one indeterminate case were reported. The gene sequence of the HCV in one of the acute cases and in the indeterminate case differed by one nucleotide.

"Three of four patients (75%) who received saline flushes on November 16, 1998, at 22:00 had acute HCV infection, while none of the nine patients who did not receive saline flushes during that time had HCV infection," reported Dr. Krause, an Epidemic Intelligence Service officer with the CDC. No other significant exposures to the virus were identified.

The nursing staff used multidose vials for saline flushes but reportedly changed syringes between patients. The researchers believe that the virus was transmitted to three of the patients through contamination of the multidose saline vial with an infected patient's blood, possibly by accidental reinsertion of a syringe or needle.

BENCHMARKS HELP REDUCE VANCOMYCIN USE

National benchmarks on vancomycin use may be "a powerful tool" to guide intervention and practice changes, reported Rachel M. Lawton, MPH, of the CDC's Hospital Infections Program, and colleagues.

These researchers studied the impact of feedback on vancomycin use among hospitals participating in the Intensive Care Antimicrobial Resistance Epidemiology (ICARE) project, which is a laboratory-based surveillance system for antimicrobial resistance and antimicrobial use. Participants were given comparative data between phase II (January 1996 through December 1997) and phase III (April 1998 through July 1999) of the project. In the fall of 1999, the researchers conducted a phone survey of 20 hospitals participating in both phases to determine if the feedback resulted in any practice changes.

At all of the hospitals, infection control staff provided comparative data to specific committees (60%), pharmacy and therapeutic committees (35%), and infection control committees (35%).

Seven participants used a hospital-wide approach to change vancomycin use: Three required prior approval or order forms for vancomycin use; two conducted a drug utilization evaluation; and two redistributed the Hospital Infection Control Practices Advisory Committee guidelines on appropriate vancomycin use. Five other hospitals used an ICU-specific approach: Three removed vancomycin as a surgical prophylaxis option for cardiac surgeons, and two educated staff on appropriate uses of vancomycin.

The researchers found that the two ICU practice changes caused significant reductions in vancomycin use. Thus, they concluded that ICU-specific approaches may be more effective than hospital-wide approaches.

RISK OF IVD-RELATED BLOODSTREAM INFECTION

Support for use of new technology to prevent bloodstream infections caused by intravascular devices (IVDs) was found in a recent meta-analysis of 223 studies. The data provide clinical benchmarks for the upper bound of acceptable risk for bloodstream infection with the various IVDs in clinical use.

Daniel M. Kluger, MD, and Dennis G. Maki, MD, who are both from the University of Wisconsin Medical School in Madison, examined all prospective studies that used microbiologically based criteria for IVD-related bloodstream infections. They found that the best way to determine the risk for infection was to calculate the mean number of infections per 100 IVDs and per 1,000 days of IVD use.

The rate of infection per 100 IVDs used was higher among cuffed than among noncuffed central venous catheters (CVCs). However, when the data were reanalyzed to look at the infection rate per 1,000 days of IVD use, the result was just the opposite: The rate was markedly lower for cuffed than for noncuffed CVCs. As shown in Table 2, the lowest rates per 1,000 days were found for antibiotic-coated noncuffed CVCs (0.2), subcutaneous ports (0.2), peripherally inserted central catheters (0.4), and cuffed hemodialysis CVCs (0.5).

MONOCHLORAMINE FOR LEGIONELLA DISINFECTION IN A HOSPITAL SETTING

Building upon previous findings of a reduced incidence of Legionnaire's disease at hospitals located in cities that use monochloramine to disinfect drinking water, researchers have found the same effect when monochloramine was added to the hot water supply of a single hospital building.

Ligia Pic-Aluas, MD, and colleagues measured colony forming units (CFUs) of Legionella, free chlorine levels, and the temperature of the water supply in an administrative building at the Washington Hospital Center in Washington, DC. Samples were obtained from eight sites, three times a week for three weeks, before the intervention. A monochloramine-generating unit was then installed in the hot water supply and the same variables--as well as pH, monochloramine levels, and free ammonia levels--were measured for four more weeks.

The mean daily Legionella colony counts fell from 71.9 CFUs/mL before to 0.13 CFUs/mL after the intervention. This decline was strongly correlated with the addition of monochloramine to the water supply.

The researchers acknowledged that there was an unintended fluctuation in free chlorine levels during the study period and that monochloramine levels were lower than intended. Nevertheless, the results suggest that monochloramine disinfection may be very effective when used in a single building. In addition, the method is inexpensive, safe, and noncorrosive to plumbing materials.

--Kristin Della Volpe

Return to table of contents