314 APIC GuidelineAJIC

August 1996

this guideline, entitled “Guideline for Handwash-ing and Hospital Environmental Control, 1985,”was published in .November 1985.2 This latterguideline did not recommend chemical germi-cides that were formulated for use on medicalequipment or environmental surfaces in healthcare facilities. Rather, the revised CDC guidelinefocused on strategies for disinfection and steril-ization of medical (equipment used in the healthcare setting.

The purpose of this revised Association forProfessionals in Infection Control and Epidemi-ology, Inc. (APIC) Guideline, which is an updatedversion of previous publications,3-6 is to assisthealth care professi~onals in their decisions involv-ing the judicious selection and proper use ofspecific disinfectants. In the preparation of thisguideline, articles in the scientific literature wereused to augment the manufacturers’ label claimsbecause these claims were not consistently verifi-ables7 Disinfectant failures noted at variance tolabel claims may be caused by deficiencies intesting methods7 or by improperly conductedtests8 In addition, in-use testing has not beenincorporated into all Environmental ProtectionAgency (EPA) methods (e.g., Association of Offi-cial Analytical Chemists [AOAC] tuberculocidalactivity test), and fa:ilures have been demonstratedwhen some disinfectants are subjected to condi-tions, such as dilution, age, and presence oforganic matter, that challenge their antimicrobialactivity.g It should also be recognized that EPAregistration claims are based on microbicidalefficacy data submitted by manufacturers. TheEPA does not independently test disinfectantsbefore their registration, but in 1990 the EPAresumed postregistration testing of chemical ster-ilants to ensure that they satisfy their registeredlabel claims.

DEFINITIONS

For the purpose of this guideline, the followingdefinitions will be used:

Sterilization is the complete elimination ordestruction of all forms of microbial life. It isaccomplished by either physical or chemicalprocesses. Steam under pressure, dry heat, lowtemperature sterilization processes (ethylene ox-ide [ETO] gas, plasma sterilization) and liquidchemicals are the principal sterilizing agentsused. The term sterilization is intended to conveyan absolute meaning, not a relative one.

Disinfection describes a process that eliminates

BACTERIALSPORESBacillus subtilis

4MYCOBACTERIA

Mycobacterium tuberculosisa

NONLIPID OR SMALLVIRUSESpolio virus

4FUNGI

Trichophyton spp.

VEGETATIVE BACTERIAPseudomonas aeruginosa

Staphylococcus aureusJJ

LIPID OR MEDIUM-SIZED VIRUSESherpes simplex virus

hepatitis B virushuman immunodeficiency virus

Fig. 1. Descending order of resistance to germicidalchemicals. This hierarchy considers broad classifications ofmicrobial categories. It is considered a rough guide togeneral susceptibility of microorganisms to disinfectants.Adapted from Favero MS, Bond WV Chemical disinfectionof medical and surgical materials. In: Block SS, ed.Disinfection, sterilization and preservation. 4th ed. Philadel-phia: Lea & Febiger, 1991:621.

many or all pathogenic microorganisms, with theexception of bacterial spores, from inanimateobjects. In health care settings, this is generallyaccomplished by the use of liquid chemicals or wetpasteurization. The efficacy of disinfection isaffected by a number of factors, each of which maynullify or limit the efficacy of the process. Some ofthe factors that have been shown to affect disin-fection efficacy are the previous cleaning of theobject, the organic load on the object, the type(Fig. 1) and level of microbial contamination, theconcentration of and exposure time to the germi-cide, the physical configuration of the object (e.g.,crevices, hinges, lumens), and the temperatureand pH of the disinfection process. More extensiveconsideration of these and other factors that affectboth disinfection and sterilization may be found inseveral references. 3, 6t lo-l3 Chemical disinfectantscan be classified by several schemes. This guide-line uses the terminology used by the CDC’s“Guideline for Handwashing and Hospital Envi-