A quantitative study of the survival of two species of Candida on porous and non-porous environmental surfaces and hands.

AIMS: In spite of the importance of many species of Candida as human pathogens, little is known about their ability to survive on animate and inanimate surfaces. Such information is essential in understanding the vehicles and modes of their spread, and in designing proper infection control strategies against them. The aim of this study was to generate comparative quantitative data in this regard. METHODS AND RESULTS: The survival of one clinical isolate each of Candida albicans and C. parapsilosis on two types of hard inanimate surfaces (glass and stainless steel) and two types of fabrics (100% cotton and a blend of 50% cotton and 50% polyester) was evaluated under ambient conditions (air temperature 22 +/- 2 degrees C; relative humidity 45-62%) using quantitative test protocols. The survival of C. albicans was also assessed on human skin, using the fingerpads of adult volunteers as carriers. Each carrier surface received 10 microl of the test suspension containing a soil load to simulate body fluids. When dried on glass and stainless steel carriers, C. albicans and C. parapsilosis remained viable for at least three and 14 days, respectively. Both species could survive for at least 14 days on both types of fabric. On the skin, 20% of the viable C. albicans remained detectable one hour post-inoculation. SIGNIFICANCE AND IMPACT OF THE STUDY: This quantitative and comparative study demonstrated the potential for, and differences in the ability of clinically significant species of Candida to remain viable on porous and non-porous inanimate surfaces as well as on human hands. These results should help in understanding the epidemiology of nosocomial infections due to Candida, and in designing better prevention and control strategies against them.

Testing chemical germicides against Candida species using quantitative carrier and fingerpad methods.

Six disinfectants were tested against Candida albicans, C. parapsilosis and C. tropicalis using quantitative carrier tests based on glass (QCT-1) and metal (QCT-2) surfaces. C. albicans was also used to test four topical agents by a fingerpad method. Hard water (200 ppm as CaCO(3)) was the product diluent. In preliminary tests with QCT-1 and QCT-2, the testing was with or without a soil load; subsequent tests and fingerpad tests included soil. In QCT-1 and QCT-2, each carrier received 10 microL (5.0 x 10(6) - 1.0 x 10(7)colony forming units) of Candida, and was air dried for 1 h, then exposed to 1 mL or 50 microL of test product at 22 +/- 2 degrees C for up to 10 min. Controls received an equivalent volume of saline. For fingerpad tests, each digit received 10 microL of inoculum, which was allowed to dry and exposed to 1 mL of test product for 20 s. Inoculated plates of Sabouraud's dextrose agar were held for 48 h at 30 degrees C and colonies counted to determine reductions in colony forming units. In tests on both hard surfaces and fingerpads, ethanol and products based on ethanol reliably and rapidly inactivated all the Candida species tested. Products with sufficient potency to have tuberculocidal claims produced substantial reductions in the titre of C. albicans, although some showed a lesser reduction in titre of C. tropicalis and C. parapsilosis. This may reflect differences in cell hydrophobicity between Candida species, and highlights the need for care in selecting a suitable surrogate for disinfectant tests. The quantitative carrier and fingerpad protocols are suitable for assessing the activity of disinfectants and topical antiseptics against candida.

Preventing the spread of hepatitis B and C viruses: where are germicides relevant?

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are the most prevalent bloodborne pathogens. Infections caused by these organisms can become chronic and may lead to liver cirrhosis and carcinoma. Limited chemotherapy is now available, but only HBV can be prevented through vaccination. Both viruses are enveloped and relatively sensitive to many physical and chemical agents; their ability to survive in the environment may not be as high as often believed. As a result, their spread occurs mainly through direct parenteral or percutaneous exposure to tainted body fluids and tissues. Careful screening of and avoiding contact with such materials remain the most effective means of protection. Nevertheless, the indirect spread of these viruses, although much less common, can occur when objects that are freshly contaminated with tainted blood enter the body or contact damaged skin. Germicidal chemicals are important in the prevention of HBV and HCV spread through shared injection devices, sharps used in personal services (such as tattooing and body piercing), and heat-sensitive medical/dental devices (such as flexible endoscopes) and in the cleanup of blood spills. Microbicides in vaginal gels may also interrupt their transmission. General-purpose environmental disinfection is unlikely to play a significant role in the prevention of the transmission of these viruses. Testing of low-level disinfectants and label claims for such products against HBV and HCV should be discouraged. Both viruses remain difficult to work with in the laboratory, but closely related animal viruses (such as the duck HBV) and the bovine viral diarrhea virus show considerable promise as surrogates for HBV and HCV, respectively. Although progress in the culturing of HBV and HCV is still underway, critical issues on virus survival and inactivation should be addressed with the use of these surrogates.

Impact of changing societal trends on the spread of infections in American and Canadian homes.

Infectious diseases continue to exert a heavy toll on human health even in industrialized countries. Recent data from the World Health Organization suggests that infectious diseases are the leading cause of death in the world. Many changing trends in our society have a known or potential impact on infectious disease spread and may have an impact on the normal routine of home hygiene. Important amongst these societal trends are increasing population and life expectancy, changes in urbanization, grouping of susceptibles, increased ambulatory and home care, increased immunosuppression, increased and faster travel, changes in technology, increasing antibiotic resistance as a result of misuse of antibiotics, changes in food and water consumption, and changes in personal cleaning, washing, and laundry practices. This review will highlight these factors and their impact on home hygiene and steps that may be needed to reduce the risk from infections.

Ex vivo protocol for testing virus survival on human skin: experiments with herpesvirus 2.

We report an ex vivo method, which uses pieces of human skin excised during routine plastic surgery, for testing survival of hazardous pathogens. Using this procedure, we compared the survival of human herpesvirus 2 on human skin and on metal disks. At the physiological skin temperature of 32 degrees C, the half-life of the virus on skin was 1.44 h while on metal disks it was 0.36 h. Even at ambient temperature (22 degrees C), the virus lost infectivity faster (half-life = 0.96 h) on metal disks than on the skin at 32 degrees C. The method described could be used to assess the survival of other human pathogens on skin and to evaluate the germicidal activity of handwashing agents and other topicals.

Mycobactericidal testing of disinfectants: an update.

Tuberculosis, a major killer in developing countries, is on the rise again in industrialized nations. AIDS, increased use of immunosuppression and the emergence of multiple drug-resistant Mycobacterium tuberculosis (MDR-TB) have further enhanced its significance. TB is projected to cause 3.5 million deaths per year by 2000. Also, other types of mycobacteria are being incriminated in human infections with increasing frequency. Thus, the enhanced risk of nosocomial and iatrogenic spread of mycobacteria is forcing a review of infection control in general and claims of mycobactericidal activity of disinfectants in particular. Mycobacteria are more resistant to disinfection than enveloped viruses and other types of vegetative bacteria, but a proper comparison with non-enveloped viruses requires more data. Flaws in currently used protocols for mycobacterial activity are: (i) a lack of proper quantitation; (ii) unrealistically long contact times at higher than ambient temperatures; (iii) absence of a suitable organic load; (iv) ineffective neutralizers; (v) unsuitable surrogates for M. tuberculosis; (vi) improper recovery media; and (vii) inappropriate types of carriers. Furthermore, we have recently found a product meant for 14 day reuse to become non-mycobactericidal after only a week under actual use in an endoscopy unit. These considerations make the available data on product efficacy unreliable, especially in view of the increasing threat from MDR-TB. Recent findings suggest that the use of Mycobacterium terrae as a surrogate, better recovery media, flat surfaces as carriers, elimination of neutralizers, proper removal of cell clumps and a required > or = 4 log10 reduction in the number of colony forming units of the test bacterium after disinfectant treatment should make mycobacteridal tests more precise and reliable, thus making product registration and selection easier. There is also an urgent need to develop standardized protocols to determine the mycobactericidal activity of disinfectants under conditions of reuse.

Catheter cleaning for re-use in intermittent catheterization: new light on an old problem.

Clean intermittent catheterization is a common method of urinary elimination for people with Spinal Cord Injuries. The methods of catheter cleaning for re-use, however, have not been validated with research studies. This study compared the effectiveness of Hydrogen Peroxide, vinegar, dishwashing detergent, and tap water alone to clean catheters contaminated with Pseudomonas aeruginosa and Escherichia coli. The effect of rinsing and drying before cleaning was also examined, as well as the effect of storage in paper or plastic bags after cleaning. Results indicated that rinsing and drying catheters immediately after use was the most effective at reducing bacteria to very near zero. Elements of a procedure are outlined, as well as plans for further development and testing of a rinse & dry procedure for catheter cleaning and re-use.

Feasibility of a combined carrier test for disinfectants: studies with a mixture of five types of microorganisms.

BACKGROUND: There is mounting concern regarding the efficacy of many germicides on the market because officially recognized germicidal tests for various classes of microorganisms vary widely and often lack reproducibility and proper quantitation. We report here a carrier method for simultaneously and quantitatively assessing the efficacy of liquid chemical germicides against a mixture of microorganisms of varying degrees of resistance. METHODS: In the test, each small glass cup (10 mm wide x 14 mm long) was contaminated with 10 microliters of a standardized mixture of Staphylococcus aureus, Mycobacterium bovis bacille Calmette-Guérin, Trichophyton mentagrophytes spores, Sabin poliovirus type 1, and Bacillus stearothermophilus spores in 5% fetal bovine serum. The inoculum was dried for 60 minutes under ambient conditions and covered with 60 microliters of the disinfectant under test or a balanced salt solution control for the desired contact time. The carrier was then placed in 2940 microliters of an eluent and the eluates assayed separately for the five microorganisms. Tap water was used to dilute the test product as needed. RESULTS: Of the 11 products tested, 2% alkaline glutaraldehyde, 0.6% sodium hypochlorite (about 5000 ppm free chlorine), and a 0.4% quarternary ammonium compound containing 23% hydrochloric acid were effective against all five challenge organisms. A hard-surface spray containing 0.1% o-phenylphenol with 79% ethanol was effective against all but bacterial spores; 70% (volume/volume) ethanol alone and povidone-iodine (1% available iodine) were effective against S. aureus, the mycobacterium, and the fungus; a 3% solution of peroxygen compounds was effective only against S. aureus and the poliovirus; 1.5% chlorhexidine gluconate, 0.06% quaternary ammonia compound, and 0.03% o-phenylphenol + 0.03% p-tertiary amylphenol could inactivate nothing but S. aureus; and 3% hydrogen peroxide was ineffective in all tests. CONCLUSIONS: This method shows promise for use with various classes of microorganisms, individually or as mixtures. Its application should enable the classification of germicides according to spectrum of activity.

Bactericidal, virucidal, and mycobactericidal activities of reused alkaline glutaraldehyde in an endoscopy unit.

Baths with 2% alkaline glutaraldehyde are often reused for 14 days to decontaminate flexible fiberoptic endoscopes (FFEs) between patients, but the effect of such reuse on the disinfectant's activity has not been known. Many busy endoscopy units also disinfect FFEs with contact times shorter than those recommended by the disinfectant manufacturer. We therefore collected samples of the disinfectant over the 14-day reuse period from two manual and one automatic bath used for bronchoscopes and gastroscopes at a local hospital. Control samples were also collected from a manual bath of 2% alkaline glutaraldehyde which did not receive any endoscopes. The germicidal activities of the samples were assessed in a carrier test against a mixture of hepatitis A virus, poliovirus 1 (Sabin), and Pseudomonas aeruginosa; the mixture also contained either Mycobacterium bovis or Mycobacterium gordonae. Bovine serum (5%) was the organic load. The criterion of efficacy was a minimum of a 3-log10-unit reduction in the infectivity titers of the organisms tested. The initial disinfectant concentration in all the baths was nearly 2.25%; it became about 1.8% in the control bath and fell to approximately 1% in the three test baths after 14 days. No protein was detected in the control bath, while its concentration rose gradually in the test baths to a maximum of 1,267 micrograms/ml after 14 days. With a contact time of 10 min at 20 +/- 2 degrees C, all the samples from the control bath were effective against all the test organisms and all the samples from all the test baths were also effective against P. aeruginosa. With a contact time of 10 or 20 min at 20+/-2 degrees C, the virucidal and mycobactericidal activities of the samples from the test baths showed broad-spectrum germicidal activity when the contact time was increased to 45 min and the temperature was raised to 25 degrees C. These findings emphasize the care needed in the disinfection of FFEs, especially in view of the increasing threat of AIDS and the resurgence of tuberculosis.

Comparative in vivo efficiencies of hand-washing agents against hepatitis A virus (HM-175) and poliovirus type 1 (Sabin).

The abilities of 10 hygienic hand-washing agents and tap water (containing approximately 0.5 ppm of free chlorine) to eliminate strain HM-175 of hepatitis A virus (HAV) and poliovirus (PV) type 1 (Sabin) were compared by using finger pad and whole-hand protocols with three adult volunteers. A mixture of the two viruses was prepared in a 10% suspension of feces, and 10 microliters of the mixture was placed on each finger pad. The inoculum was allowed to dry for 20 min, and the contaminated area was exposed to a hand-washing agent for 10 s, rinsed in tap water, and dried with a paper towel. In the whole-hand protocol, the hands were contaminated with 0.5 ml of the virus mixture, exposed for 10 s to a hand-washing agent, washed, and dried as described above. Tryptose phosphate broth was used to elute any virus remaining on the finger pads or hands. One part of the eluate was assayed directly for PV with FRhK-4 cells, while the other part was first treated with a PV-neutralizing serum and then assayed for HAV with the same cell line. The results are reported as mean percentages of reduction in PFU compared with the amount of infectious virus detectable after initial drying.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical disinfection to interrupt transfer of rhinovirus type 14 from environmental surfaces to hands.

Rhinoviruses can survive on environmental surfaces for several hours under ambient conditions. Hands can readily become contaminated after contact with such surfaces, and self-inoculation may lead to infection. Whereas hand washing is crucial in preventing the spread of rhinovirus colds, proper disinfection of environmental surfaces may further reduce rhinovirus transmission. In this study, the capacities of Lysol Disinfectant Spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm of free chlorine), a quaternary ammonium-based product (7.05% quaternary ammonium diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) were compared in interrupting the transfer of rhinovirus type 14 from stainless steel disks to fingerpads of human volunteers upon a 10-s contact at a pressure of 1 kg/cm2. Ten microliters of the virus, suspended in bovine mucin (5 mg/ml), was placed on each disk, and the inoculum was dried under ambient conditions; the input number on each disk ranged from 0.5 x 10(5) to 2.1 x 10(6) PFU. The dried virus was exposed to 20 microliters of the test disinfectant. The Lysol spray was able to reduce virus infectivity by > 99.99% after a contact of either 1 or 10 min, and no detectable virus was transferred to fingerpads from Lysol-treated disks. The bleach (800 ppm of free chlorine) reduced the virus titer by 99.7% after a contact time of 10 min, and again no virus was transferred from the disks treated with it.(ABSTRACT TRUNCATED AT 250 WORDS)

Survival of hepatitis A virus on human hands and its transfer on contact with animate and inanimate surfaces.

The survival of hepatitis A virus (HAV; strain HM175) on the hands of five volunteers was determined by depositing 10 microliters of fecally suspended virus on each fingerpad and eluting the inoculum after 0, 20, 60, 120, 180, and 240 min. The amount of virus recovered from each fingerpad at 0 min was approximately 6.0 x 10(4) PFU. At the end of 4 h, 16 to 30% of the initially recoverable virus remained detectable on the fingerpads. HAV inocula (10 microliters; approximately 1.0 x 10(4) PFU) placed on fingerpads or 1-cm-diameter metal disks were used to determine virus transfer to clean surfaces upon a 10-s contact at a pressure of nearly 0.2 kg/cm2. When the inoculum was dried for 20 min, virus transfer from fingerpad to fingerpad, fingerpad to disk, and disk to fingerpad ranged from 2,667 to 3,484 PFU, while 0 to 50 PFU could be transferred after 4 h of drying. Elevation of the contact pressure alone from 0.2 to 1.0 kg/cm2 resulted in an approximately threefold increase in the amount of virus transferred. Incorporation of friction (10 half turns of the finger during 10 s of contact) with the low and high levels of pressure gave two- and threefold increases in the PFU of virus transferred, respectively. Pressure and friction were found to significantly affect HAV transfer (F = 33.98; P less than 0.05), irrespective of the mode of transfer used. No statistically significant interaction was observed between mode of transfer and pressure or friction. The findings of this quantitative study suggest that human hands may play an important role in the direct as well as the indirect spread of HAV.

Studies on the stability of a human adenovirus-rabies recombinant vaccine.

Human adenovirus type 5 containing the rabies virus glycoprotein gene (rHAd-RG1) has potential for the oral vaccination of animals. The stability of this recombinant was tested indoors and outdoors by measuring the loss in virus infectivity. Under indoor conditions the stability of the recombinant virus was studied in an egg yolk-containing commercial stabilizer and a simple buffered salt solution (EBSS; Earle's balanced salt solution) at 4 degrees C and room temperature (24-25 degrees C). Over 16 days, there was a more rapid loss in virus titer at room temperature than at 4 degrees C in both suspending media; however, these differences were slight and may be significant when the overall stability of the vaccine is considered. When the virus was mixed with either 10% (w/v) fox or skunk feces or EBSS, placed on stainless steel disks and the disks kept under ambient conditions (air temperature 24-25 degrees C; relative humidity 45-50%), there was a more rapid decline in virus titer in the fecal suspensions (3% remained after 72 h) than in EBSS (26% remained after 72 h). When bait-coated blister packs of the vaccine were placed in an outdoor location in the fall (October) season, there was a larger drop in the virus titer for vaccines placed in the sun (54% over 32 days) than for those in the shade (40% over 32 days). Incorporating proteinaceous stabilizers in the vaccine samples for outdoor study showed virus stability was not enhanced in their presence.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of cloth, paper, and warm air drying in eliminating viruses and bacteria from washed hands.

We compared the efficiency of paper, cloth, and electric warm air drying in eliminating rotaviruses and Escherichia coli remaining on finger pads washed with 70% isopropanol, a medicated liquid soap, an unmedicated liquid soap, or tap water alone. The contaminated area on the finger pads of a volunteer was exposed to the hand-washing agent for 10 seconds and then rinsed in 40 degrees C tap water. The washed areas were dried for 10 seconds by one of the three methods. Irrespective of the hand-washing agent used, electric air drying produced the highest and cloth drying the lowest reduction in the numbers of both test organisms. These findings indicate the importance of selecting the right means for drying washed hands, particularly when less effective hand-washing agents are used.

Potential role of hands in the spread of respiratory viral infections: studies with human parainfluenza virus 3 and rhinovirus 14.

Hands often become contaminated with respiratory viruses, either directly or through contact with contaminated surfaces. Spread of such viruses could then occur by touching the nasal mucosa or the conjunctivae. In this quantitative study, we compared the survival of mucin-suspended human parainfluenza virus 3 (HPIV-3) and rhinovirus 14 (RV-14) and the transfer of the viruses to and from the fingers of adult volunteers. When each finger pad was contaminated with 10 microliters of either HPIV-3 (1.3 x 10(5) to 5.5 x 10(5) PFU) or RV-14 (2.1 x 10(4) to 1.1 x 10(5) PFU), less than 1.0% of HPIV-3 and 37.8% of RV-14 remained viable after 1 h; after 3 h, nearly 16% of RV-14 could still be detected, whereas HPIV-3 became undetectable. Tests on the potential spread of viruses from contaminated hands or surfaces were conducted 20 min after contamination of the donor surface by pressing together donor and recipient surfaces for 5 s. Transfer of HPIV-3 from finger to finger or finger to metal disk could not be detected, but 1.5% of infectious HPIV-3 was transferred from disk to finger. Irrespective of the type of donor or recipient surface, 0.7 to 0.9% of RV-14 was transferred. The relatively rapid loss of HPIV-3 infectivity on hands suggests that their role in the direct spread of parainfluenza viruses is limited. However, the findings of this study further reinforce the view that hands can be vehicles for rhinovirus colds. These results also suggest a role for nonporous environmental surfaces in the contamination of hands with respiratory viruses.

Survival and disinfectant inactivation of the human immunodeficiency virus: a critical review.

The possibility of contracting acquired immunodeficiency syndrome (AIDS) through accidental or inapparent parenteral exposure to human immunodeficiency virus (HIV) has raised concerns among recipients of blood products, health-care professionals, and others who have contact either with HIV or with AIDS patients. Along with these concerns has come an increasing interest in the physical and chemical methods that may be used to inactivate HIV in blood products and other contaminated fluids as well as on contaminated objects and surfaces. This review critically examines the available information on the survival of HIV and the methods used for its inactivation, particularly those that rely on chemical disinfection. Although the risk of acquiring HIV from contaminated materials may be slight compared with that of acquiring other blood-borne pathogens, such as hepatitis B virus, the effectiveness of disinfectants used under clinical conditions may have been overestimated.

Survival and vehicular spread of human rotaviruses: possible relation to seasonality of outbreaks.

In developing countries rotavirus infections account for nearly 6% of all diarrheal episodes and for 20% of diarrhea-associated deaths of young children. Even in industrialized countries rotavirus diarrhea in the young is among the leading causes of hospitalization. In temperate regions institutional outbreaks of the disease occur mainly in cold dry weather, whereas in tropical settings the seasonality is less well defined. Waterborne outbreaks of rotavirus gastroenteritis have been recorded; air, hands, fomities, and food may also act as vehicles for this infection. Rotaviruses can survive for weeks in potable and recreational waters and for at least 4 hours on human hands. In air and on nonporous inanimate surfaces, the survival of rotaviruses is favored by a relative humidity of less than or equal to 50% and viral infectivity can be retained for several days. Rotaviruses are relatively resistant to commonly used hard-surface disinfectants and hygienic hand-wash agents.

Effect of relative humidity and air temperature on survival of hepatitis A virus on environmental surfaces.

Stainless steel disks (diameter, 1 cm) were contaminated with fecally suspended hepatitis A virus (HAV; strain HM-175) and held at low (25% +/- 5%), medium (55% +/- 5%), high (80% +/- 5%), or ultrahigh (95% +/- 5%) relative humidity (RH) at an air temperature of 5,20, or 35 degrees C. HAV survival was inversely proportional to the level of RH and temperature, and the half-lives of the virus ranged from greater than 7 days at the low RH and 5 degrees C to about 2 h at the ultrahigh RH and 35 degrees C. In parallel tests with fecally suspended Sabin poliovirus (PV) type 1 at the low and ultrahigh RH, all PV activity was lost within 4 h at the low RH whereas at the ultrahigh RH it remained detectable up to 12 h. HAV could therefore survive much better than PV on nonporous environmental surfaces. Moreover, the ability of HAV to survive better at low levels of RH is in direct contrast to the behavior of other enteroviruses. These findings should help in understanding the genesis of HAV outbreaks more clearly and in designing better measures for their control and prevention.

Chemical disinfection of hepatitis A virus on environmental surfaces.

Hepatitis A virus disinfection was assessed on contaminated stainless-steel disks. Ten microliters of fecally suspended hepatitis A virus was deposited on the center of each disk, dried for 20 min, and then covered with 20 microliters of the test product for 1 min. Of the 20 formulations tested, only 2% glutaraldehyde, a quaternary ammonium formulation containing 23% HCl (toilet bowl cleaner), and sodium hypochlorite (greater than 5,000 ppm [greater than 5,000 micrograms/ml] of free chlorine) reduced the virus titer by greater than 99.9%; phenolics, iodine-based products, alcohols, and solutions of acetic, peracetic, citric, and phosphoric acids were unable to do so.

Efficacies of selected disinfectants against Mycobacterium tuberculosis.

The activities of 10 formulations as mycobactericidal agents in Mycobacterium tuberculosis-contaminated suspensions (suspension test) and stainless steel surfaces (carrier test) were investigated with sputum as the organic load. The quaternary ammonium compound, chlorhexidine gluconate, and an iodophor were ineffective in all tests. Ethanol (70%) was effective against M. tuberculosis only in suspension in the absence of sputum. Povidone-iodine was not as efficacious when the test organism was dried on a surface as it was in suspension, and its activity was further reduced in the presence of sputum. Sodium hypochlorite required a higher concentration of available chlorine to achieve an effective level of disinfection than did sodium dichloroisocyanurate. Phenol (5%) was effective under all test conditions, producing at least a 4-log10 reduction in CFU. The undiluted glutaraldehyde-phenate solution was effective against M. tuberculosis and a second test organism, Mycobacterium smegmatis, even in the presence of dried sputum, whereas the diluted solution (1:16) was only effective against M. smegmatis in the suspension test. A solution of 2% glutaraldehyde was effective against M. tuberculosis. This investigation presents tuberculocidal efficacy data generated by methods simulating actual practices of routine disinfection.