• New Tuberculosis Guidelines Issued by ATS and CDC

• Hepatitis B Immunity

NEWS FEATURES

Ortho-phthalaldehyde (OPA), a new chemical sterilant, received clearance by the Food and Drug Administration in October, 1999. OPA solution is a clear, pale blue liquid with a pH of 7.5. It contains 0.55% ortho-phthalaldehyde. OPA has demonstrated excellent microbiocidal activity in in vitro studies. For example, Gregory and coworkers demonstrated that OPA has shown superior mycobactericidal activity (5-log₁₀ reduction in 5 minutes) compared to glutaraldehyde. The mean times required to effect a 6-log₁₀ reduction for M. bovis using 0.21% OPA was 6 minutes compared to 32 minutes using 1.5% glutaraldehyde (Infect Control Hosp Epidemiol 1999;20:324-330). In a recent publication, Walsh and colleagues tested OPA against a wide range of microorganisms including glutaraldehyde-resistant mycobacteria and Bacillus subtilis spores (J Appl Microbio 1999;86:1039-1046). OPA showed good activity against the mycobacteria tested including the glutaraldehyde-resistant strains, but 0.5% OPA was not sporicidal within 270 minutes of exposure. Increasing the pH from its unadjusted level (about 6.5) to pH 8 improved the sporicidal activity of OPA.

OPA has several potential advantages compared to glutaraldehyde. It requires no activation, is not a known irritant to the eyes and nasal passages, has excellent stability over a wide range of pH (pH 3-9), does not require exposure monitoring, and has a barely perceptible odor. OPA, like glutaraldehyde, has excellent material compatibility. Olympus America has not completed its endoscope compatibility testing for OPA. However, Olympus Tokyo has completed the compatibility testing of OPA and it did not produce any functional damage to any tested instruments. A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus it must be handled with caution (Infect Control Hosp Epidemiol 1999;20:69-76). However, staining would indicate improper handling that requires additional training and/or personal protective equipment (PPE). PPE should be worn when handling contaminated instruments, equipment and chemicals (gloves, eye protection, fluid resistant gowns). Since it was only recently cleared for use as a high-level disinfectant, only limited clinical studies are available. In one clinical-use study of 100 endoscopes exposed for 5 minutes to OPA, a (5-log₁₀ reduction in bacterial load was demonstrated. Further, the OPA was effective over a 14 day usage cycle (J Hosp Infect 1994;26:15-26). Manufacturer's data (Advanced Sterilization Products, Irvine, CA) show that the OPA will last longer before reaching its minimum effective concentration (MEC) limit (about 82 cycles) compared to glutaraldehyde (MEC after 40 cycles) in an automatic endoscope reprocessor. Disposal must be done in accordance with local and state regulations. If OPA disposal via the sanitary sewer is restricted, glycine (25 grams/gallon) can be used to neutralize the OPA and make it safe for disposal.

The high-level disinfectant label claims for OPA solution at 20^oC vary worldwide but is 12 minutes in the United States. (Emerging Infect Dis, in press).

CJD is a degenerative neurologic disorder that affects about 1 person per million population per year. It is transmitted by a proteinaceous infectious agent or prion. Since CJD is not readily inactivated by conventional disinfection and sterilization procedures and because of the invariably fatal outcome of CJD, the procedures for disinfection and sterilization of the CJD prion have been both conservative and controversial. We have recently critiqued the literature and developed evidence-based guidelines to prevent cross-transmission of infection from CJD-contaminated medical devices. This has resulted in a policy change at UNC Health Care System.

Our policy now states that we will only modify our disinfection and sterilization practices if it is a high risk tissue (i.e., brain, spinal cord, eyes), a high risk patient (i.e., known or suspected CJD or other transmissible spongiform encephalopathies, rapidly progressive dementia, or dura mater transplant or human growth hormone injection) and a high risk device (i.e., critical or semicritical device). In all other cases we do not modify our sterilization and disinfection protocols, including an endoscope that is used on a CJD patient, since blood or mucous membrane contact is not considered via experimental or epidemiological data a high risk tissue.

REGULATORY/LEGISLATIVE

In October 1999, the North Carolina TB Policy Manual underwent revision (see SPICE Report of the Month, Volume 3, Number 6, November-December 1999 and Volume 4, Number 1, January-February 2000). An updated guideline issued by the American Thoracic Society (ATS) and the Center for Disease Control and Prevention (CDC) has necessitated a further revision of the state policy by adoption of the latest "Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection" published in the April 2000 issue of Am J Resp Crit Care Med, Vol 161, pp S221-S247. Journal article is online at http://ajrccm.atsjournals.org/cgi/content/full/161/4/S1/S221

QUESTION OF THE MONTH

Q: What should the occupational health specialist do to be compliant with OSHA's Bloodborne pathogen (BBP) Final Rule if a healthcare worker refuses to have the post-vaccination serology for determining immunity to hepatitis B within 1 to 2 months after the administration of the third vaccine dose?

A: SPICE contacted J. Edgar Geddie, Ph.D., the Health Standards Officer in the North Carolina Department of Labor, Division of OSHA. In accordance with the new compliance directive (CPL 2.44D) and the BBP rule, an employee signed declination form would be appropriate for healthcare workers refusing post-vaccination testing for hepatitis B and it should be part of the individual's medical record.

COURSES FOR THE INFECTION CONTROL PROFESSIONAL

"Infection Control Part II: The ICP as an Environmentalist" will be held September 25-29, 2000 at the Holiday Inn in Chapel Hill.

"Infection Control in Home Health and Hospice" will be held October 30, 2000 at The Friday Center in Chapel Hill.

Contributors to Report of the Month: Karen K. Hoffmann, RN, MS, CIC; William A. Rutala, PhD, MPH, David J. Weber, MD, MPH, Eva P. Clontz, MEd.

To subscribe to the Report of the Month, send email to spice@unc.edu

Report of the Month is also available on the home page of the Statewide Program for Infection Control and Epidemiology at http://www.unc.edu/depts/spice/

The Statewide Program for Infection Control and Epidemiology (SPICE) is funded by the General Assembly of North Carolina to serve the State. SPICE is not a regulatory agency but provides education and consultation to North Carolina healthcare facilities.

Copyright 2000 North Carolina Statewide Program for Infection Control and Epidemiology

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