/publications/issue/2005/2005-02/2005-02-9224

Prevention and Treatment of Iatrogenic Infections

Author: Monica Holmberg, PharmD

Can a visit to a health care facility actually make you sicker? Unfortunately, hospitals, long-term care facilities, clinics, and dialysis centers all host microorganisms. In healthy individuals, intact skin is a wonderful barrier?most microorganisms are unable to penetrate the keratin layer of the epidermis. Additionally, healthy individuals are armed with mucous membranes and functioning immune systems to ward off infection. Hospitalized patients, however, often lack these protective barriers.1 In environments where microorganisms abound, a skin puncture from catheters or intravenous devices may penetrate the patient's first line of defense and open the door for iatrogenic infection.

Each year, an estimated 2 million patients develop iatrogenic infections. Of these 2 million, ~90,000 die from their infections.2 Staphylococci, streptococci, and enterococci are some of the more common organisms producing iatrogenic infections.3 More troubling, however, are the organisms developing resistance to antibiotics. This article will address these resistant iatrogenic infections and how health care providers can play a crucial role in both the prevention of transmission and the treatment of iatrogenic infections.

MRSA

One of the most infamous hospital-acquired infections, methicillin-resistant Staphylococcus aureus (MRSA), has been a health care issue since the 1960s. Initially, S aureus was resistant to methicillin and other beta-lactam penicillins. The number of antibiotics to which it is now resistant has expanded to include cephalosporins, erythromycin, clindamycin, gentamicin, trimethoprim/sulfamethoxazole, and ciprofloxacin.

MRSA colonization typically results in bacteremia, pneumonia, and infections in soft tissues, skin, and surgical areas. Potential patient outcomes are dreary: 20% to 50% of patients with MRSA will die from this primarily nosocomial infection.4 Although any hospitalized patient is potentially susceptible to MRSA infections, the more critically ill are at greater risk (Table). Interestingly, recent data have suggested that treatment with fluoroquinolones?especially ciprofloxacin?may increase the incidence of MRSA infection or colonization.5

The spread of MRSA is a major concern and should be taken seriously by all health care providers. The Centers for Disease Control and Prevention recommends contact isolation for patients with MRSA colonization or infection.6 Unfortunately, undetected MRSA colonization can be easily transmitted to other patients via health care providers. Clinicians should take extra precautions with all direct patient contact, even with those patients who do not have known MRSA infections or colonization.

Frequent hand washing and barrier precautions are basic measures for MRSA control4 (Sidebar). Providers should be reminded to disinfect stethoscope diaphragms with an alcohol pad.6 Health care workers also should be aware that MRSA can hide in unsuspected places: computer keyboards, sink faucets, and white coats have been found to be contaminated with MRSA.4,6 These contaminations could have been prevented by appropriate cleansing and hand washing.

Additionally, artificial nails increase the risk of MRSA transmission. The nails provide a habitat for MRSA colonization and can cause tears in gloves. Despite fashion trends, many health care facilities discourage providers who have direct patient contact from wearing artificial nails.4

Regular and adequate cleansing of patient and staff areas is essential to reduce MRSA transmission. When one considers that 69% to 73% of patient hospital rooms remain contaminated with MRSA after the patient is discharged, the prevalence of MRSA is not surprising. Simply wiping the affected area with a cloth saturated with a quaternary ammonium compound is not effective in MRSA eradication. Saturating the area itself and allowing it to dry for 10 minutes has been found effective, however.6

As a result of the antimicrobial resistance of MRSA, treatment options are limited. Vancomycin, a glycopeptide antibiotic, is usually considered the drug of choice. It is administered intravenously and is eliminated renally.4 Dosing is patient-specific; protocols vary for each hospital but usually accommodate for the patient's renal function and weight.

Other treatment options include linezolid and quinupristin/dalfopristin. Linezolid traditionally is reserved for patients who are either resistant or intolerant to vancomycin. Although effective, quinupristin/dalfopristin is infrequently used due to its cost and its discouraging side effects. Daptomycin, a newer antibiotic agent, has shown efficacy against vancomycin-susceptible infections and offers promise to patients unable to tolerate vancomycin. Clinicians should note that daptomycin should not be used for pneumonia because it does not achieve adequate levels in the respiratory tract.7

VRE and Beyond

Ubiquitous MRSA poses a serious health risk. The overuse of antibiotics produces the concern about resistance?and just as S aureus has grown resistant to methicillin, so has it to vancomycin. Aside from VRSA [vancomycin-resistant S aureus], 2 other vancomycin-resistant strains already have been identified: vancomycin-intermediate S aureus (VISA) and vancomycin-resistant Enterococcus faecium (VRE). So far, only 3 VRSA and a handful of VISA infections have been reported in the United States. VRE, however, is a more prevalent problem.7

VRE infections in the bloodstream correlate with an increased rate of recurrent infection and increased fatality.6 As with MRSA, the prevention of its transmission is obviously the first step in the battle against VRE.

A limited number of agents are available to treat VRE. Linezolid has demonstrated efficacy; however, its use is not without concern. Cost and the development of resistance are the 2 major issues associated with linezolid treatment.

On the horizon, oritavancin is in phase 3 trials and shows promise against vancomycin-resistant infections. Its FDA review is pending.7

Additional Concerns

Medications available in multiple-dose vials (MDVs) may present an additional pathway for iatrogenic infection. In 2001, 2 deaths resulted from a contaminated vial of iomeprol in Germany, attracting media attention and igniting pressure to conduct MDV contamination studies. Drugs in lipid formulations, such as propofol, and preservative-free formulations appear to be associated with a higher risk of contamination. Despite their illusion of sterility, even the mini-spikes in bacterial filters have been found with contamination. Despite the risk associated with specific MDV formulation, however, the prevention of contamination ultimately remains with health care providers and their MDV technique.8

An immunocompromised organ transplant patient is at a higher risk for any infections, and about 50% of these infections are hospital-acquired. The most common sites for infection are the respiratory, gastrointestinal, and urinary tracts.1

As the emergence of resistant microorganisms continues to present treatment challenges, the prevention of iatrogenic infections will be a major concern for all health care providers. Hand washing and patient contact precautions are effective ways to minimize the transmission of disease and to improve patient outcomes.

Dr. Holmberg is a pharmacist with Phoenix Children's Hospital, Phoenix, Ariz.

For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. A. Stahl, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: astahl@mwc.com.