Antibiotic controls, IC measures fight resistance

Reviewing strategies to curtail misuse of antibiotics

Controlling the spread of antimicrobial-resistant pathogens in health care facilities requires two complementary strategies: improving the use of antimicrobials and implementing appropriate infection control measures, recommends John Boyce, MD, hospital epidemiologist at Miriam Hospital in Providence, RI.

Boyce reviewed current approaches to the problem of antibiotic resistance as a faculty member at the Centers for Disease Control and Prevention’s recent public health training network satellite broadcast. With antibiotic resistance on the rise, the CDC and other concerned medical groups have issued guidelines outlining strategies to prevent and control emerging resistance.¹

Current approaches include optimizing perioperative antimicrobial prophylaxis, developing strategies to make the best use of empiric anti microbial therapy, using educational and administrative measures to improve antimicrobial-prescribing practices, monitoring antimicrobial use, providing feedback to hospital administrators and health care workers on the occurrence and the impact on antimicrobial resistance, and implementing clinical practice guidelines for antimicrobial use, Boyce noted.

"These recommendations emphasize that all health care facilities must make controlling antimicrobial use and reducing antimicrobial resistance strategic goals of their institutions," he said. "These two goals should be supported by hospital administrators, department heads, physicians, and everyone else in the facilities."

Surgical prophylaxis, for example, is an important area to consider when looking at measures to reduce the overuse of antimicrobials in acute care facilities."To optimize perioperative antimicrobial prophylaxis, make sure that the first intravenous dose of the antimicrobial is given within one hour of making the surgical incision," he said. "Also, remember to limit the duration of perioperative prophylaxis to 24 hours whenever possible."

In addition, Boyce suggested ways to optimize the type and the duration of empiric antimicrobial therapy."Reduce the use of vancomycin in febrile, neutropenic patients," he recommended. "Several studies have shown that empiric vancomycin therapy is seldom necessary in these patients. If vancomycin is given empirically, then physicians should consider discontinuing it if the patient’s infection is not caused by beta lactam-resistant gram-positive organisms."

Educational approaches

Another key aspect of improving antimicrobial use is ongoing educational activities. That might include lectures describing optimal choices of antimicrobials for clinical syndromes such as pneumonia or bacteremia, or providing physicians with pocket-sized cards that list your facility’s common antimicrobial susceptibilities and costs, he said. Hospitals that use computerized physician orders can post educational messages or prompts on computer screens.

Another approach is to require that physicians obtain approval from an infectious disease consultant before ordering certain antimicrobials. Other measures to reduce overuse of antimicrobials include automatic stop orders, having pharmacists interact directly with physicians on the wards, limiting the promotion of antimicrobials by pharmaceutical representatives, and forming a multidisciplinary antimicrobial management team to deal with use and resistance, Boyce said. Monitoring antimicrobial usage by service or ward also can help pinpoint patterns of overuse or abuse.

"If your facility isn’t already monitoring anti microbial use by service or by ward, I would suggest that you start doing that now," Boyce said.

Clinical practice guidelines — such as those developed on vancomycin use by the CDC Hospital Infection Control Practices Advisory Committee (HICPAC) — also can improve antimicrobial use, he added. "We gave pocket-sized cards listing the HICPAC guidelines for vancomycin use to interns and residents," he said. "In addition, instruction on antimicrobial use took place during ward rounds. This combination of measures led to a 17% reduction in intravenous vancomycin use at Miriam Hospital."

Boyce stressed the importance of providing feedback to all health care workers on the occurrence and the impact of antimicrobial resistance. "It’s not enough to simply monitor and provide reports to a selected group of people in the hospital," he said. "Everyone in the facility needs to be informed."

Cyclic rotation of selected antimicrobials can be an effective strategy as well, he noted, citing a study dealing with gentamicin resistance at the Minneapolis Veterans Affairs Medical Center.² Clinicians there implemented a requirement that the infectious disease service must approve the use of gentamicin before it could be prescribed."

They also implemented a plan for cyclic rotation of selected antimicrobials, Boyce said. "In this instance, gentamicin would be rotated with amikacin, which physicians could prescribe without prior approval of the infectious disease service."

When gentamicin accounted for a high percentage of aminoglycosides use, the level of gentamicin resistance among gram-negative bacilli was high, the authors found. Conversely, when gentamicin was restricted and amikacin was used more frequently, the prevalence of gentamicin resistance decreased.

"The strong temporal association between the amount of gentamicin used and the prevalence of gentamicin resistance is impressive, and suggests that the restriction of gentamicin was responsible for the reductions in gentamicin resistance among gram-negative bacilli," Boyce emphasized.

Overall, the combination of antibiotic measures and infection control efforts may be the most successful strategy, he noted, citing a study at the University of Virginia Medical Center in Charlottesville. Clinicians there used a combination of antimicrobial restrictions and aggressive infection control processes to control the spread of vancomycin-resistant enterococci (VRE.)³ By using computerized entry systems, physicians who requested vancomycin were presented with the HICPAC list of recommended uses for vancomycin, he explained. The physician then had to specify one of the approved uses to justify ordering the vancomycin for each patient.

As a result of this strategy, inappropriate use of vancomycin decreased from 61% to 30%, and the amount of vancomycin prescribed decreased by 50%. At the same time, the hospital instituted strict infection control measures, including the use of contact precautions by caregivers and weekly surveillance cultures of high-risk patients on affected wards. The combination of antimicrobial restriction plus infection control measures enabled them to reduce the prevalence of VRE from 30% at the beginning of the outbreak to less than 1% for the following 3½ years, he noted.

"I think this is a pretty convincing example of the best way to control antimicrobial resistance," Boyce said. ". . . We must control the unnecessary use or abuse of antimicrobials while simultaneously using appropriate surveillance and barrier precautions. This is the only way we will reduce nosocomial transmission of antimicrobial-resistant pathogens."

References

1. Goldmann DA, Weinstein RA, Wenzel RP, et al. Strategies to prevent and control the emergence and spread of antimicrobial-resistant microorganisms in hospitals: A challenge to hospital leadership. JAMA 1996; 275:234-240.

2. Gerding DN, Hughes RA, Weiler M, et al. Aminogly coside resistance and aminoglycoside usage: Ten years experience in one hospital. Antimicrob Agents Chemother 1991; 35:1,284-1,290.

3. Anglim AM, Farr B, et al. Effect of a vancomycin policy on ordering practices during an outbreak of vancomycin-resistant Enterococcus faecium. Arch Intern Med 1997; 157: 1,132-1,136.