Phenolic Disinfectants Research Articles

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1,040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%), 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

Inactivation of prions by physical and chemical means

Prions are very resistant to inactivation, and accidental transmission has occurred through the use of inadequate decontamination procedures. Strong sodium hypochiorite solutions achieve inactivation but other chlorine-releasing compounds are less effective. 2M sodium hydroxide leads to substantial but incomplete inactivation; other chemical procedures such as the use of proprietary phenolic disinfectants are much less less effective. Infectivity can survive autoclaving at 132–138 °C, and under certain conditions the effectiveness of autoclaving actually declines as the temperature is increased. The small resistant subpopulations that survive autoclaving are not inactivated by simply re-autoclaving, and they acquire biological characteristics that differentiate them from the main population. Despite the limitations of autoclaving, combining autoclaving (even at 121 °C) with a sodium hydroxide treatment is extremely effective. Protein-fixation (e.g., by ethanol or formalin) substantially enhances the thermostability of these agents. This suggests that future successful inactivation strategies might best be developed by studying procedures that avoid protein-fixation.

Effectiveness of infection control program in controlling nosocomial Clostridium difficile

Objective: To report the effectiveness of use of comprehensive infection control measures to reduce the incidence of Clostridium difficile (CD) in an acute-care teaching hospital. Methods: All CD infections were reviewed by the infection control coordinator from 1987 to 1996. The Centers for Disease Control and Prevention’s nosocomial infection definition was used. CD-inclusion criteria remained unchanged during the study period. Interventions were started in 1990. Interventions: The interventions used were: (1) Isolation policy-revision and enforcement, which included universal precautions policy, (2) educational program-monthly to all health care workers, (3) phenolic disinfectant for environmental cleaning, (4) triclosan (0.03%) soap for handwashing, (5) centralization of sterilization department, (6) cart-washer installation, and (7) aggressive surveillance activity. Results: From 1987 to 1989, before the interventions, a total of 466 CD infections (mean 155 per year) occurred. From 1990 to 1996, after the interventions, 475 infections (mean 67 per year) occurred. Incidence of CD decreased by 60% from 1990 to 1996. Conclusion: The sustained decrease of nosocomial CD during the 7-year period demonstrated the effectiveness of aggressive infection control measures that involve multiple disciplines. (AJIC Am J Infect Control 1998;26:588-93)

Phenolic household disinfectants — further precautions required

Phenolic disinfectants (e.g. Meytol, Dettol, etc.) are widely used for domestic purposes. Instructions on the bottles are clearly given with regards to the dilutions that should be used. In domestic cleaning, these instructions are often ignored and higher concentrations are used with the thinking that ‘the more I pour, the cleaner it gets!’. Furthermore, cleaning equipment is some-times stored without prior rinsing with fresh water. As water evaporates much faster than phenol, the solution on stored mops/brushes, etc. becomes progressively more and more concentrated and can cause chemical burns when these utensils are handled at a later time. We therefore suggest that two further instructions should be added to the usual instructions on bottles of household phenolic disinfectants, namely: ‘wear gloves when performing domestic cleaning’ and ‘wash all cleaning equipment with plenty of fresh water after use’. We support this by a case report of a 65-year-old man who sustained full-thickness, painless chemical burns to his right hand after handling a moist mop which had been used for cleaning a carpet with a phenolic household disinfectant solution 2 days earlier.

Disinfecting equine facilities.

Disinfection of equine premises provides a challenge to farm managers, in view of the variety of surfaces which may be contaminated and the wide variety of horse pathogens. Of the commonly occurring infectious diseases for which disinfection and disease control are especially important, rotavirus diarrhoea, salmonellosis and strangles are the most difficult to control. Phenolic disinfectants have been scientifically demonstrated to be effective in the presence of organic matter and are also virucidal. When used after thorough cleaning and rinsing of stall surfaces, phenolics have proved effective in controlling outbreaks of disease. In addition, 10% iodophors used for washing hands and cleaning equipment are also virucidal and bactericidal. Quaternary ammonium compounds, chlorhexidine, bleach and pine oil are readily available commercially, but are ineffective disinfectants in the presence of the organic matter encountered on horse farms.

Bacteriological safety and low-air-loss beds.

The distribution of bacteria into the environment while managing a simulated 1 0% body surface area burn on either a standard hospital bed or a low-air-loss bed was examined in this study. The extent of contamination was similar for both types of bed but operating the bed head/foot mechanism of the low-air-loss bed might be a hazard in certain circumstances. The investigation demonstrated the insidious build up of bacteria within a patient treatment cubicle. Means for eliminating possible contamination of the low-air-loss bed were investigated and an effective method devised. It was also found that commonly employed topical therapeutic agents for burns did not affect the air sac fabric of the low-air-loss bed, but a standard phenolic disinfectant was deleterious. The cleaning and disinfecting procedures were found to be effective in clinical practice.

Susceptibility to antibacterials and compared metabolism of suspended bacteria versus embedded bacteria in biofilms

Bacterial resistance in biofilms to antiseptics is a well-known phenomenon for which numerous explanations have been suggested. In a dynamic flow model using an E. coli biofilm, a phenolic disinfectant displayed bactericidal activity only at a concentration five times greater than that effective against suspended bacteria. It is now established that phenols are effective antibacterials only for protein-synthesizing bacteria. Hence the question arose as to whether deeply embedded bacteria in our biofilms still exhibited an active metabolism. Therefore we evaluated the respiratory activity and the intracellular ATP level in biofilm bacteria, before and after contact with the disinfectant. The β-galactosidase activity, induced by the addition of lactose to the medium on day 4 (the day before the test), was measured in order to check whether diffusion of exogenous molecules through the biofilm was easily achieved. The results suggested that deeper layers of bacteria in five-day-old E. coli biofilms displayed reduced metabolic activity compared to the bacteria in suspension. Nevertheless, removal of the upper bacterial layers with a disinfectant induced recovery of the previously dormant metabolism.

A Five Year Evaluation of Acute Exposures to Phenol Disinfectant (26%)

A five year retrospective review of all exposures to a high concentration phenol disinfectant (Creolin Disinfectant 26% phenol) reported to a regional poison center located 96 cases, with 16 cases lost to follow up. There were 60 oral-only exposures, 7 dermal-only exposures and 12 oral/dermal exposure. One patient was an inhalation exposure. Fifty-two cases (65%) were evaluated in a hospital. Eleven patients with oral exposures (14%) experienced rapid CNS depression, but no seizures occurred. Vomiting, coughing, and stridor was noted in 14, 7 and 4 patients respectively. Burns were noted in 17 of 72 (24%) patients with oral exposure and 5 of 19 (26%) with dermal exposure. Seventeen patients underwent endoscopy. Tissue sloughing was noted in one case. All other burns were first degree. No cardiovascular complications occurred. Twenty-eight patients (35%) were followed at home via telephone with one episode of vomiting and one episode of dermal irritation occurring. CNS toxicity from exposure to a high concentration phenol containing cleaning product appears to be rapid in onset. The absence of serious toxicity and major chemical burns in this series does not eliminate concern with the corrosive and systemic risks of phenol poisoning.

Investigations of the effectiveness of detergent washing, drying and chemical disinfection on contamination of cleaning cloths

Detergent washing, drying and chemical disinfection for decontamination of cleaning cloths was investigated with cloths contaminated by use in the domestic environment. Detergent washing produced only limited reductions in microbial contamination and cloths then stored at room temperature for 24 h showed increases in contamination due to multiplication of residual survivors. For effective and consistent decontamination of cloths, detergent washing followed by drying at 80 degrees C for 2 h was required. Hypochlorite and phenolic disinfectants produced significant reductions in contamination, but chemical disinfection may be unreliable where cloths are heavily contaminated.

The use of a phenolic disinfectant in animal husbandry

The formulation of a specialised disinfectant, which produces a clear solution on addition to water, as opposed to an emulsion, and designed to meet the needs of livestock house hygiene routines is described. Laboratory tests indicated that mixed phenols are effective in controlling organisms associated with the diseases of farm livestock particularly in view of modern methods of intensive farming. Field trials substantiated the results obtained from the laboratory tests.

A comparison of hypochlorite and phenolic disinfectants for disinfection of clean and soiled surfaces and blood spillages

Suspension test methods were used to compare phenolic and hypochlorite disinfectants under conditions as recommended for use in hospitals. Using plasma to simulate soiled conditions, Clearsol (1% v v ) and Stericol (2% v v ) produced satisfactory disinfection, (i.e. 5 log reduction in 5 mins against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa in the presence of up to 50% v v plasma (25 mg ml −1 plasma protein). Although sodium dichloroisocyanurate (NaDCC) at 2500 ppm AvCl 2 was effective in the presence of up to 20% plasma, compared to 10% plasma for sodium hypochlorite 2500 ppm, sensitivity of NaDCC to inactivation was greater than for phenolics. In the presence of blood, both hypochlorites and phenolics were substantially inactivated, although here the effectiveness of NaDCC at 10,000 ppm was equivalent to the phenolics. Our results indicate that hypochlorites at 10,000 ppm, Clearsol 1% and Stericol 2% may be ineffective for treatment of blood spills unless applied at v:v ratios of 9 parts disinfectant to 1 part blood. In this situation, chlorine-releasing powder formulations, which produce higher AvCl 2 concentrations and contain spilled material, offer an effective alternative.

Foodborne and Waterborne Disease in Canada — 1980 Annual Summary

Data on foodborne disease in Canada in 1980 are compared with those for 1979. A total of 759 incidents, comprising 621 outbreaks and 138 single cases, caused illnesses in 7,122 persons in 1980. Compared with 1979, fewer incidents but more cases occurred. Salmonella, Staphylococcus aureus, Clostridium perfringens and Bacillus cereus caused most illnesses. The main Salmonella serovars involved were S. typhimurium, S. heidelberg and S. enteritidis. Campylobacter and Citrobacter infections were reported for the first time. Seven episodes of paralytic shellfish poisoning occurred, more than twice the number in 1979. There were also 53 incidents and 100 cases of chemical origin; rancid compounds, extraneous matter and metals were the main chemicals involved. Unusual chemical problems included turkey contaminated with calcium chloride brine, antimony deliberately added to a beverage to induce sickness, ammonia-soaked frozen potato puffs, chocolates contaminated with phenol disinfectant and toluene in popcorn twists. There were nine deaths from salmonellosis, paralytic shellfish poisonings and hemolytic uremic syndrome. About 34% of incidents and 51% of cases were associated with meat and poultry. Vegetables, fruits, Chinese food, marine food and bakery products were also vehicles that contributed significantly to foodborne disease. Mishandling of food took place mainly in foodservice establishments (41.2% of incidents, 74.3% of cases), homes (15.8% of incidents, 6.0% of cases) and food processing establishments (10.1% of incidents, 8.7% of cases). Food processors were responsible for salmonellosis from turkey rolls (440 cases) and staphylococcal intoxication from cheese curds (62 cases) and many small outbreaks and single cases. Most incidents occurred in Ontario (43.9%) and British Columbia (21.7%), but on a 100,000 population basis, British Columbia recorded more incidents (6.2) than Nova Scotia and Yukon (both 4.5) and Ontario (3.9). Narrative reports of seven foodborne disease incidents are presented. Four incidents of waterborne disease were documented in 1980, the same number as in 1979. All were caused by bacterial agents, with Campylobacter and Salmonella responsible for most cases. Pseudomonas aeruginosa infected the skin of 10 persons in a whirlpool bath.

Persistent isolation of an unusual Pseudomonas species from a phenolic disinfectant system.

A well-characterized unusual Pseudomonas species contaminated the piped disinfectant system of a newly-opened laminar air flow intensive care facility. This organism was frequently isolated (10(4)-10(6) cfu/ml) from phenolic diluted 1:256 in the system, and could also be recovered (0.01-0.2 cfu/ml) from undiluted phenolic. During the 20-month period when this unusual Pseudomonas was present, none of the severely compromised, granulocytopenic oncology patients treated in the intensive care facility were either colonized or infected with this Pseudomonas sp. Eradication of the organism from the system proved difficult and was accomplished by removing a contaminated reservoir of diluted phenolic disinfectant followed by transient cleansing of the system with very high concentrations (84,000 ppm) of chlorine. This experience demonstrates that phenolics should be added to the list of disinfectants which can harbor Pseudomonas spp. in the clinical setting.

Estimation and verification of the environmental fate ofO-Benzyl-p-chlorophenol

O-Benzyl-p-chlorophenol (OBPC) has widespread use in the United States as a hospital phenolic disinfectant; annual production averages less than 4.5×106 kg. Disposal is primarily via municipal waste treatment where biodegradation removes 95% of the OBPC as confirmed by modeling and field measurements. Measured influent and effluent concentrations from 16 sites in the United States averaged 14.8 μg/L and 0.8 μg/L, respectively. These measured data confirm the utility of the Holman model (1981) for predicting the concentration of household chemicals during sewage treatment. OBPC is apparently rapidly metabolized by fish and has a low potential to bioconcentrate in biota (bioconcentration factor for OBPC is 75). Based upon laboratory studies, biodegradation and photolysis are the major transformation processes in the environment; hydrolysis and volatilization rates are insignificant. The five percent of the total OBPC reaching the aquatic environment was predicted by two models to partition to the water column resulting in average surface water concentrations of 0.001–0.008 μg/L. Environmental sampling at 18 sites in the eastern United States confirmed that the average concentration in surface waters was <0.11 tμg/L.

Heinz Body Hemolytic Anemia in Newborns and Failure of Laboratory Studies to Implicate a Phenolic Disinfectant

Two unrelated, white, female, premature infants in the same hospital nursery contemporaneously exhibited features of an acute, Heinz body hemolytic anemia: decreased levels of hemoglobin and hematocrit, anisocytosis, fragmented cells, hyperbilirubinemia, reticulocytosis, and red cell inclusion bodies. Physical examination and laboratory studies failed to reveal the etiology of this process. Epidemiologic studies indicated a possible association between the reaction and the improper use and inappropriately high concentration of a phenolic disinfectant. Such an association has been suggested previously between similar products and epidemics of hyperbilirubinemia. Despite extensive experimental efforts (four species, six routes of administration, newborn rats, splenectomized rats, direct incubation with age-matched human cord blood), the reaction could not be produced in the laboratory. It may be highly specific for the intact, human, premature infant. Perhaps the hyperbilirubinemia reported previously had an erythrocytic rather than hepatic origin.

Antiseptic and antibiotic resistance in gram-negative bacteria causing urinary tract infection in spinal cord injured patients.

Fifty-seven isolates of Gram-negative bacterial species from urinary tract infections in spinal cord injured patients were tested for their sensitivity to chlorhexidine, cetrimide, glutaraldehyde, phenyl mercuric nitrate (PMN), a phenolic disinfectant (Hycolin) and a proprietary antiseptic containing a mixture of picloxydine, octylphenoxypolyethoxyethanol and benzalkonium chloride (Resiguard). None of the isolates were resistant to glutaraldehyde, Hycolin or PMN but a substantial percentage were resistant to chlorhexidine (44 per cent), cetrimide (26 per cent) and Resiguard (42 per cent). The resistant organisms were members of the genera Proteus, Providencia and Pseudomonas and they were also generally resistant to five, six or seven antibiotics. Significant correlations were observed between multiplicity of antibiotic resistance and the minimum inhibitory concentrations of the three cationic antiseptics. It is suggested that an antiseptic policy for the bladder management of spinal cord injured patients that relies on the extensive use of cationic agents might lead to the selection of a flora of notoriously drug-resistant species.

Disinfection of surgical instruments

The degree of bacterial contamination of surgical instruments after operations and its reduction by cleaning and/or disinfection has been determined. Approximately 60 per cent of used instruments carried <10 1 micro-organisms, 80 per cent <10 2 and 90 per cent <10 3; and whether the operations were clean, clean-contaminated, contaminated or dirty did not significantly affect the microbial load. The contamination was not reduced by soaking instruments for 1 h in detergent, but an hour's immersion in a phenolic disinfectant reduced the levels to 80 per cent with <10 1 organisms and 98 per cent with <10 2. Similar reductions were obtained with a washer/ disinfector with a final rinse of water at >85 °C; and even better results with a different washer/disinfector without the final hot water rinse. The latter machine presumably had a better cleaning action. Instruments for manual processing should be disinfected before cleaning to minimize contamination of the cleaners' hands. However, they should preferably be processed in an efficient instrument-washer, which may not need a specific disinfection cycle, but must remain tightly closed to prevent contaminated splashes or aerosols.

Phenol and Neonatal Jaundice

The articles by Wysowski et al (Pediatrics 61:165, 1978) and Doan et al (Pediatrics 64:324, 1979), implicating the use of a phenolic disinfectant in the nursery as a cause of neonatal hyperbilirubinemia, led us to discontinue the use of phenolics and substitute chlorhexidine in its place. This change in policy was implemented with a certain degree of concern as "low level" disinfectants, such as chlorhexidine or quaternary ammonium compounds, have been implicated themselves as factors in the spread of nosocomial infections.1,2

Inactivation of Mycobacterium bovis in meat products.

The time-temperature combinations necessary to destroy Mycobacterium bovis in meat products were determined. In any given time, M. bovis was destroyed at temperatures 6 to 7 degrees C (ca. 12 degrees F) lower than those necessary for destruction of members of the Mycobacterium avium-Mycobacterium intracellulare complex. Hence, any processing heat adequate to kill M. avium-M. intracellulare-complex organisms will provide a very large safety factor with respect to M. bovis. Benzalkonium chloride treatment of wiener specimens for cultural examination effectively destroyed the normal flora of wiener emulsion without reducing the numbers of M. bovis. Treatment with a phenolic disinfectant followed by formaldehyde vapor was effective in disinfecting equipment contaminated with meat emulsion containing M. bovis.

A Comparative Investigation of the Bactericidal and Fungicidal Effects of Three Phenolic Disinfectants

Two methods, a capacity use‐dilution test and another employing geometrical dilution, are used when comparing the bactericidal and fungicidal effects of a phenolic disinfectant containing 45% (w/w) o‐phenylphenol in an aqueous soap solution of linseed oil (soap content 6·5% w/v) with the corresponding effects of the same phenolic compound in an aqueous soya oil soap solution (soap content 3·5% w/v). The soya oil soap did not change the disinfectant capacity on the different test organisms used. For the most resistant strain (Staphylococcus aureus) the usedilution concentration was evaluated to be slightly above 1%, i.e. 2%, which is much lower than the recommended use‐dilution concentration. However, using the same method and test organisms the capacity use‐dilution testing of a third phenolic disinfectant, containing p‐chloro‐m‐cresol and o‐benzyl‐p‐chlorophenol with a total of 9·2 (w/w) phenols in a detergent system, indicated that the recommended use‐dilution concentration should be doubled.