Disinfection of the skin with detergent preparations of Irgasan DP 300 and other antiseptics

The lethal effect of soap on Schistosoma mansoni cercariae in water

BACKGROUND

Schistosomiasis is a parasitic disease which is spread through skin contact with water containing Schistosoma cercariae. Drug treatment has been the main control method, but it does not prevent reinfection. The use of soap can be a complementary measure to reduce transmission. Therefore, this study investigates the quantitative effect of different soaps on the mortality of Schistosoma mansoni cercariae.

METHODOLOGY

Four soaps including two powder soaps (Kleesoft and Omo) and two bar soaps (B29 and Rungu) which are used in a schistosomiasis-endemic Tanzanian village were studied. S. mansoni cercariae were exposed to powder soaps of 0 (control), 10, 50, 75, 100 and 1000 mg/L and to bar soaps of 0 (control), 100, 500 and 1000 mg/L. The highest concentration of 1000 mg/L was selected based on the laboratory-estimated average soap concentration during handwashing. Cercariae were observed under a microscope after 0, 5, 15, 30, 45 and 60 minutes of exposure to determine their survival.

CONCLUSIONS

All four soaps can kill S. mansoni cercariae and this lethal effect was related to soap concentration and exposure time. At the highest concentration of 1000 mg/L, all cercariae were dead at 5 minutes post-exposure with two powder soaps and Rungu, while 100% cercarial death was achieved between 5 minutes to 15 minutes for B29. Almost all cercariae survived after being exposed to 10 mg/L powder soaps and 100 mg/L bar soaps for 60 minutes. Powder soaps were more lethal than bar soaps. Considering the widely varying concentrations of soap during real-world hygiene activities and the necessity for a very high soap concentration to eliminate all cercariae in a short 5-minute exposure, providing the efficacy of soap in preventing schistosomiasis becomes challenging. Future studies should investigate whether soap can influence alternative mechanisms such as making cercariae unable to penetrate the skin, thereby providing protection.

Application of Antiviral Polyoxometalates to Living Environments—Antiviral Moist Hand Towels and Stationery Items

Safe, secure, and environmentally friendly active substances should be developed. VB (virus block) refers to an antibacterial/antiviral mixture of two kinds of polyoxometalates (PMs), i.e., K11H[(VO)3(SbW9O33)2]·27H2O (VB2) and α-Na2[SbW9O33]9− (VB3), and polyhexamethylene biguanide (PHMB). VB was demonstrated to exert antiviral effects on cultured cells. The effects were maintained even in hygiene products or solids. The antiviral effects were analyzed by reverse transcription–polymerase chain reaction (RT–PCR), and the results were correlated with TCID50, potentially eliminating the need for handling infectious viruses. VB was demonstrated to be extremely effective (up to 99.99% inhibition) in cultured cells, with antibacterial/antiviral effects maintained in VB-containing hygiene products. VB was applied to solids, demonstrating their high applicability and versatility. VB withstands high temperatures regardless of materials because its effects are enhanced by more frequent contact with viruses and bacteria due to the increased surface area of the compound.

In vitro Antimicrobial Effects of Virus Block, Which Contains Multiple Polyoxometalate Compounds, and Hygienic Effects of Virus Block-Supplemented Moist Hand Towels

BACKGROUND

Historical evidence has verified the multifaceted antiviral efficacy of polyoxometalates (PMs).

METHODS

We carried out a study to investigate the antimicrobial effects of each of the 5 substances comprising virus block (VB): 3 PMs that have antibacterial and antiviral activity, an antibiotic agent, and an antibacterial agent. We also investigated the effectiveness of the addition of VB to moist hand towels in a study involving 120 volunteers. The time-dependent changes in metal ion concentrations in aqueous VB solution were analyzed using inductively coupled plasma atomic emission spectroscopy.

RESULTS

The metal elements in the aqueous VB solution remained stable for 12 weeks without undergoing time-dependent changes.

DISCUSSION

Further investigations were performed to study hand hygiene using moist hand towels in daily life settings. To this end, 120 volunteers provided 240 specimens that were used to investigate the presence of antibacterial compounds on the volunteers' hands before and after hand towel use. An aliquot of each specimen was suspended in phosphate-buffered saline and plated on agar media, and the number of colonies formed was counted. Normal bacterial flora found on the hands of the volunteers was investigated before and after the use of 4 different moist hand towels.

CONCLUSIONS

The effects of VB and PMs were superior to those of commercial moist hand towels, indicating that effective data were obtained that may be useful for the practical application of the tested items.

Occurrence, efficacy, metabolism, and toxicity of triclosan

Triclosan has broad-spectrum anti-microbial activity against most gram-negative and gram-positive bacteria. It is widely used in personal care products, household items, medical devices, and clinical settings. Due to its extensive use, there is potential for humans in all age groups to receive life-time exposures to triclosan, and, indeed, triclosan has been detected in human tissues and the environment. Data gaps exist regarding the chronic dermal toxicity and carcinogenicity of triclosan, which is needed for the risk assessment of triclosan. The US Food and Drug Administration (FDA) nominated triclosan to the National Toxicology Program (NTP) for toxicological evaluations. Currently, the NTP is conducting several dermal toxicological studies to determine the carcinogenic potential of triclosan, evaluate its endocrine and developmental-reproductive effects, and investigate the potential UV-induced dermal formation of chlorinated phenols and dioxins of triclosan. This paper reviews data on the human exposure, environmental fate, efficacy of anti-microbial activity, absorption, distribution, metabolism and elimination, endocrine disrupting effects, and toxicity of triclosan.

Safety and effect of chlorhexidine skin cleansing on skin flora of neonates in Bangladesh

BACKGROUND

Chlorhexidine cleansing of newborn skin is a highly promising intervention for reducing neonatal mortality in developing countries, yet little is known of the mechanism of action. This study examined the impact of a single skin cleansing of hospitalized newborn infants in Bangladesh with baby wipes containing 0.25% chlorhexidine on both qualitative and quantitative skin flora.

METHODS

Within 72 hours of birth, the skin of newborns admitted to Dhaka Shishu Hospital was wiped with baby wipes containing 0.25% chlorhexidine (n = 67) or placebo (n = 66) solution. Skin condition was assessed and skin swabs were taken from 3 sites (axillary, peri-umbilical, inguinal) at baseline and 2 hours, 24 hours, 3 days and 7 days after treatment. Skin flora was quantified and colonizing species were identified.

FINDINGS

Skin cleansing with chlorhexidine had no adverse effects on skin condition, and resulted in minimal reduction (mean 0.5 degrees C) in body temperature. Positive skin culture rates 2 hours after skin cleansing were approximately 35%-55% lower than the baseline rates for placebo and chlorhexidine groups at all 3 sites. For the chlorhexidine group, positive skin culture rates remained significantly lower than the baseline rates for 24 hours to 3 days, whereas for the placebo group, beyond the first 2-hour follow-up, these values were not lower than baseline in any of the 3 sites.

INTERPRETATION

Chlorhexidine skin treatment produced more extended skin cleansing effects than the placebo treatment. It is possible that the quantitative and qualitative reductions observed in the skin flora might contribute to reducing neonatal infections.

Efficacy of surgical preparation solutions in foot and ankle surgery

BACKGROUND

Previous studies have demonstrated higher infection rates following orthopaedic procedures on the foot and ankle as compared with procedures involving other areas of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to evaluate the efficacy of three different surgical skin-preparation solutions in eliminating potential bacterial pathogens from the foot.

METHODS

A prospective study was undertaken to evaluate 125 consecutive patients undergoing surgery of the foot and ankle. Each lower extremity was prepared with one of three randomly selected solutions: DuraPrep (0.7% iodine and 74% isopropyl alcohol), Techni-Care (3.0% chloroxylenol), or ChloraPrep (2% chlorhexidine gluconate and 70% isopropyl alcohol). After preparation, quantitative culture specimens were obtained from three locations: the hallux nailfold (the hallux site), the web spaces between the second and third and between the fourth and fifth digits (the toe site), and the anterior part of the tibia (the control site).

RESULTS

In the Techni-Care group, bacteria grew on culture of specimens obtained from 95% of the hallux sites, 98% of the toe sites, and 35% of the control sites. In the DuraPrep group, bacteria grew on culture of specimens obtained from 65% of the hallux sites, 45% of the toe sites, and 23% of the control sites. In the ChloraPrep group, bacteria grew on culture of specimens from 30% of the hallux sites, 23% of the toe sites, and 10% of the control sites. ChloraPrep was the most effective agent for eliminating bacteria from the halluces and the toes (p < 0.0001).

CONCLUSIONS

The use of effective preoperative preparation solution is an important step in limiting surgical wound contamination and preventing infection, particularly in foot and ankle surgery. Of the three solutions tested in the present study, the combination of chlorhexidine and alcohol (ChloraPrep) was most effective for eliminating bacteria from the forefoot prior to surgery.

Lipid biosynthesis as a target for antibacterial agents

Fatty acid biosynthesis, the first stage in membrane lipid biogenesis, is catalyzed in most bacteria by a series of small, soluble proteins that are each encoded by a discrete gene (Fig. 1; Table 1). This arrangement is termed the type II fatty acid synthase (FAS) system and contrasts sharply with the type I FAS of eukaryotes which is a dimer of a single large, multifunctional polypeptide. Thus, the bacterial pathway offers several unique sites for selective inhibition by chemotherapeutic agents. The site of action of isoniazid, used in the treatment of tuberculosis for 50 years, and the consumer antimicrobial agent triclosan were revealed recently to be the enoyl-ACP reductase of the type II FAS. The fungal metabolites, cerulenin and thiolactomycin, target the condensing enzymes of the bacterial pathway while the dehydratase/isomerase is inhibited by a synthetic acetylenic substrate analogue. Transfer of fatty acids to the membrane has also been inhibited via interference with the first acyltransferase step, while a new class of drugs targets lipid A synthesis. This review will summarize the data generated on these inhibitors to date, and examine where additional efforts will be required to develop new chemotherapeutics to help combat microbial infections.

Comparison of the antibacterial efficacy of 4% chlorhexidine gluconate and 1% triclosan handwash products in an acute clinical ward

The antibacterial efficacy of 4% chlorhexidine gluconate (CHG) and 1% triclosan as handwash antiseptics is well established. Few published studies have identified hand bacteria found in glove juice samples, and most studies have used nonclinical study subjects. We report a longitudinal comparative study to determine the effect of 4% CHG and 1% triclosan on the composition of the hand bacterial flora of clinical staff in a specialist surgical unit. Prehandwash and posthandwash samples were collected on 3 separate occasions throughout each day by using the glove juice method and a supervised handwashing technique. Total bacterial counts were determined as well as counts for specific pathogens including methicillin-resistant Staphylococcus aureus and coliforms. Both 4% CHG and 1% triclosan were found to effectively reduce the total hand bacterial count preduty (P =.0001). Four percent CHG also was consistently more effective at reducing the total count than was 1% triclosan. However, 1% triclosan eliminated methicillin-resistant S aureus, whereas 4% CHG failed to do so (P =.0001). Gram-negative bacteria were more likely to be eliminated after the use of 4% CHG compared with 1% triclosan. This study is the first to report the effects of 1% triclosan on the bacterial flora present on the hands of clinical staff and demonstrates the ability of 1% triclosan to eliminate methicillin-resistant S aureus.

Incidence of postoperative infection or positive culture after facial laser resurfacing: a pilot study, a case report, and a proposal for a rational approach to antibiotic prophylaxis

BACKGROUND

Laser skin resurfacing (LSR) has emerged as a popular procedure for facial rejuvenation; however, there are no clear guidelines regarding systemic antibiotic prophylaxis.

OBJECTIVE

We attempt to provide practical guidelines for antibiotic prophylaxis in LSR based on our experiences, pharmacology, and a review of the literature.

METHODS

In a pilot study, four consecutive full-face LSR patients were treated without oral or topical antibiotics. The next four patients received oral prophylaxis with a narrow spectrum antibiotic. We also report the case of a severe gram-negative infection after LSR.

RESULTS

For full-face LSR, 2 of 4 consecutive patients without antibiotic prophylaxis experienced focal Staphylococcus aureus infection. The next 4 consecutive patients, who had received gram-positive oral prophylaxis, were all culture negative after 2 days. All test sites (5 of 5) were culture negative despite the absence of systemic or topical antibiotics. One patient not in the pilot study receiving gram-positive antibiotic prophylaxis experienced a gram-negative infection.

CONCLUSION

We recommend narrow-spectrum gram-positive oral antibiotic coverage for full-face and regional LSR.

Triclosan: applications and safety

Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) is a nonionic, broad spectrum, antimicrobial agent that, because of its favorable safety profile, has been incorporated into a variety of many personal care products, including deodorant soaps, underarm deodorants, shower gels, and health care personnel handwashes. Triclosan exhibits a moderate degree of substantivity to the skin, and, in many products, it imparts a remnant antimicrobial effect. Although direct contact with the material under exaggerated exposure conditions causes dermal irritation in laboratory animals, it has only rarely been associated with skin irritation or sensitization in human being in formulated products. Acute, subacute/subchronic, and chronic toxicity profiles have been established to determine that triclosan is neither an acute oral toxicant nor that it acts as a carcinogen, mutagen, or teratogen. A new application for triclosan is in oral dentifrices for plaque control. Currently under investigation in the United States, it is approved for oral care application in Canada and many European countries.

Use of 0.3% triclosan (Bacti-Stat) to eradicate an outbreak of methicillin-resistant Staphylococcus aureus in a neonatal nursery

BACKGROUND

Once established in an institution, methicillin-resistant Staphylococcus aureus (MRSA) outbreaks have proved difficult to eradicate, despite intensive infection control measures. This report describes the nosocomial infection with MRSA of 22 male infants in a neonatal nursery during a 7-month period and the infection control procedures that effectively brought this outbreak under control and eliminated recurrence for more than 3 1/2 years.

METHODS

After a single index case of bullous impetigo caused by MRSA in a neonate discharged from the nursery 2 weeks previously, an additional 18 cases of MRSA skin infections were clustered in a 7-week period. Aggressive infection control measures were instituted, including changes in umbilical cord care, circumcision procedures, diapers, handwashing, gloves, gowns, linens, disinfection, placement in cohorts of neonates and staff, surveillance, and monitoring.

RESULTS

These measures were not effective in slowing the outbreak. The single additional measure of changing handwashing and bathing soap to a preparation containing 0.3% triclosan (Bacti-Stat) was associated with the immediate termination of the acute phase of the MRSA outbreak.

CONCLUSION

The nursery has remained free of MRSA for more than 3 1/2 years, attesting to the success of our program.

The sensitivity to chlorhexidine and cetyl pyridinium chloride of staphylococci on the hands of dental students and theatre staff exposed to these disinfectants

The aim of this investigation was to study the possible emergence of resistant isolates of the genus Staphylococcus on the hands of dental personnel who use 'Hibiscrub' (chlorhexidine-detergent preparation) and cetyl pyridinium-coated gloves. Resistance was determined by a rate-of-kill technique. In four dental student groups (first, second, third and fourth years) no microorganisms survived 30 min exposure to cetyl pyridinium chloride (CPC) or to chlorhexidine diacetate (CDA). In a theatre staff group, no microorganisms survived 30 s exposure to CPC; and only one of 23 isolates survived 30 min exposure to CDA, but was killed after 60 min exposure. It is concluded that staphylococci resistant to either of these disinfectants do not present a problem in dental students or theatre staff.

Hygienic hand disinfection: a comparative study with chlorhexidine detergents and soap

The efficacy of two chlorhexidine hand-wash detergents and liquid soap was compared in a laboratory trial using artificial contamination of fingers with Micrococcus and Serratia. Agents were assessed for both a rapid and sustained effect after a single contact, and for a cumulative persistent effect after multiple contact over four days. Disinfectant activities were compared by statistical analysis of log reduction factors and log count time gradients (decimal reduction times). The latter analysis attempted to accommodate significant subject variation in response to both agent and organism. All handwashing methods significantly reduced contamination levels. Both chlorhexidine formulations were significantly better than soap in their activity against Micrococcus, but were not more effective than soap in removing contamination with Serratia. Both chlorhexidine preparations showed significant skin persistence and were generally acceptable to subjects after prolonged use. Some effect of the formulation of the hand-wash on chlorhexidine activity was demonstrated.

Surgical hand disinfection: comparison of 4% chlorhexidine detergent solution and 2% triclosan detergent solution

The effect of 4% chlorhexidine detergent and 2% triclosan detergent on the resident flora of the hands was compared on 20 healthy volunteers. The initial and prolonged effects of the agents were assessed by a modification of the Peterson glove rinse test after multiple hand washes. Chlorhexidine detergent was significantly more effective than triclosan detergent (p less than 0.001) which in turn was more effective than non-medicated soap (p less than 0.001) for both initial and prolonged effect. Chlorhexidine, but not triclosan, showed a significantly greater prolonged effect than initial effect (p less than 0.01). Five volunteers (25%) experienced skin irritation with triclosan; no side effects were experienced with chlorhexidine.

An in-use comparison of chlorhexidine gluconate 4% w/v, glycol-poly-siloxane plus methylcellulose and a liquid soap in a special care baby unit

The effectiveness and harshness of three hand-wash agents, chlorhexidine gluconate 4%, glycol-poly-siloxane gel and a bland liquid soap were studied in-use in a Special Care Baby Unit (SCBU). Each product was used for consecutive 2-week periods by the same groups of 8 health care workers among the 56 in the SCBU. The first group had normal skin, the second had 'sensitive skin' and the third group were known MRSA nasal carriers. Blood agar and methicillin mannitol salt agar were inoculated before and after hand washing and differences in colony counts calculated. Nursing activities before washing were graded from clean to dirty on an eight-point scale and correlated with before-wash colony counts. Product acceptability was assessed with a self-reporting questionnaire. Chlorhexidine was the most effective product in reducing skin microflora but users preferred to wash with the gel preparation. The sensitive-skin group achieved the best effects from washing, irrespective of the product used. Nasal carriers of MRSA recorded the lowest reduction levels of methicillin-resistant organisms but achieved the same reduction levels as the normal-skin group for other microflora. No relationship could be established between the pre-wash activity and the pre-wash colony count. The weekly MRSA colonization rate in neonates on the SCBU remained unaffected by any of the products tested.

Evaluation of the skin disinfecting activity and cumulative effect of chlorhexidine and triclosan handwash preparations on hands artificially contaminated with Serratia marcescens

The initial and cumulative efficacy of two antiseptic handwash preparations in eliminating Serratia marcescens from hands was evaluated on volunteers. Two antiseptics with persistent skin antibacterial activity, 4% chlorhexidine gluconate in detergent and 1.5% triclosan in natural soap, were studied in a new protocol designed according to Food and Drug Administration guidelines. After a single handwash, both preparations exhibited a degerming action statistically superior to the mechanical elimination of the marker organism that was achieved by the nonmedicated controls. Following a further nine hand recontamination sequence with 10(9) colony-forming units (cfu)/mL S marcescens (mean predisinfection baseline, log10 6.6), the efficacy of chlorhexidine and triclosan was significantly augmented: the mean log10 reduction factors were 4.15 and 3.78, respectively. In the absence of internationally accepted testing standards for antiseptic handwash products, the significance of protocol variables is discussed. The advantages to preventative microbiology of antiseptics with persistent skin antibacterial activity are highlighted.

A comparison of triclosan and chlorhexidine preparations with 60 per cent isopropyl alcohol for hygienic hand disinfection

Four detergent preparations containing triclosan; two alcoholic products, containing triclosan and chlorhexidine respectively, and a detergent preparation containing chlorhexidine were compared with 60 per cent isopropyl alcohol following a single hand wash using Escherichia coli as the test organism. In vitro tests indicated that all had a high activity against hospital pathogens. The triclosan-containing preparations exhibited a significant pathogens. The triclosan-containing preparations exhibited a significant residual activity. Experiments in volunteers showed that 0.5 per cent alcoholic triclosan was significantly more effective than all other preparations tested. All the detergent preparations had an effect similar to that of 60 per cent isopropyl alcohol. None of the seven products evaluated was significantly less bactericidal than 60 per cent isopropyl alcohol.

An outbreak of streptococcal infection in a chicken factory

A large outbreak of streptococcal skin infection occurred late in the summer of 1978 in a factory which undertakes the slaughter, preparation and packing of chickens. In all, 103 episodes of infection occurred in 82 workers from a total factory establishment of 347. The highest incidence of infection was in the packing department where there was an attack rate of 44%. The routes of introduction of infection into and spread within the factory remain mostly unknown. Following the identification of cases and carriers and the institution of appropriate treatment and control measures the outbreak quickly declined. The responsible organism in the outbreak was Streptococcus pyogenes T-type 3/13/B3264, provisional M-type 'R78/55'. This is the first poultry factory outbreak in England to be reported.

Delayed antimicrobial effects of skin disinfection by alcohol

Aqueous suspensions of Staphylococcus aureus were deposited on a Millipore filter and then exposed for a few seconds to 70% ethyl alcohol. Viable counts of bacteria extracted from the filter immediately after exposure to alcohol, and, in replicate experiments, after a further period of 3 h, showed that the mean immediate reduction of 97.6% in viable counts after treatment with alcohol was followed by a further mean reduction of 67.1% in the further 3 h holding time; the same bacterial suspensions allowed to dry on Millipore filters without exposure to alcohol showed a significantly smaller mean reduction in viable counts (34.3%) during a further 3 h holding time. These findings support the view that the reported further fall in numbers of bacteria on hands while wearing gloves for 3 h after alcohol disinfection can be explained by sublethal damage to some of the bacteria, from which they can recover only if promptly inoculated on culture medium.

Metabolism of chlorodiphenyl ethers and Irgasan DP 300

1. In the rat chlorodiphenyl ethers are metabolized via two routes. The predominant reaction is aromatic hydroxylation; scission of the ether bond is a minor metabolic process. 2. In all cases, primary hydroxylation takes place ortho and meta to the ether bond. Ortho-hydroxylation leads to the formation of 'predioxins' in cases where the parent compounds contain a chlorine atom in one of the ortho positions in the second ring. 3. 5-Chloro-2-(2,4--dichlorophenoxy)phenol (Irgasan DP 300), a compound that meets the structural requirements of a predioxin, did not yield chlorodibenzo-p-dioxins or hydroxylated derivatives thereof. 4. Irgasan DP 300 is excreted unchanged in faeces and urine (partly conjugated) but is also hydroxylated to five different monohydroxy metabolites which were found in urine; three of these were also present in faeces. As a result of scission of the ether bond 2,4-dichlorophenol occurred in urine and faeces, and 4-chlorocatechol in urine. 5. Neither in the case of Irgasan DP 300, nor in that of chlorodiphenyl ethers with an ortho chlorine atom, could metabolic cyclization to chlorodibenzofurans or their hydroxylated derivatives be detected.

Failure of hand disinfection with frequent hand washing: a need for prolonged field studies

In a prolonged field trial a 4% chlorhexidine digluconate detergent scrub (Hibiscrub(R)), that had earlier proved to be an effective hand disinfectant, was studied in hospital wards. Finger tips were found to harbour more bacteria than the hand dorsum and the samples collected from them yielded more information on the bacteriological and dermatological effects of hand disinfectants in practice.In wards with a relatively low hand-washing frequency (less than 20 times in 8 hours) the bacteriological results resembled those obtained by in-use tests with volunteers. In the neonatal unit where the hand washing frequency was remarkably high, even occasionally over 100 times/8 h shift, an increase in the bacterial colony counts of the majority of the staff was recorded both before and after hand washing already after using the preparation for 1 week. Age, occupation and hand-washing frequency all correlated with the bacteriological results. Twenty-seven out of 37 persons complained of side effects such as wounds of finger tips and redness or heavy drying of the skin. Wounds, particularly on finger tips, resulted in the failure of disinfection. An increase in bacterial counts was sometimes noted without any dermatological or subjective changes. Drying of the skin was complained of less often when no increase in skin bacteria occurred.After the changeover of washing practice to a detergent followed by a rinse with spirit solution containing chlorhexidine and glycerol a decrease was recorded in the bacterial counts. It is concluded that more attention should be paid to long-term testing of hand washing and disinfection methods to ensure optimum final results in practice. It is obvious that the knowledge obtained from short time in-use testing cannot be applied to all conditions of use.

An evaluation of antiseptics used for hand disinfection in wards

The antibacterial effectiveness of hand antiseptics commonly used in wards was studied by laboratory and in-use tests and their acceptability assessed by means of a questionnaire passed to hospital staff. To determine the immediate and long-term antibacterial effects of the preparations the in-use tests were performed by groups of students. The greatest immediate reduction in bacterial counts on hands was obtained by products containing chlorhexidine. The long-term antibacterial effect was recorded with emulsions containing 3% hexachlorophane, 2% Irgasan CF3R or 4% chlorhexidine when used constantly on several consecutive days. Considerable discrepancies were recorded in the antibacterial effectiveness of some preparations when comparing laboratory and in-use test results. Therefore it is suggested that antiseptics should be tested by in-use tests which more closely resemble practical conditions before their use, or further trial, in hospital.

Comparison of two methods for assessing the removal of total organisms and pathogens from the skin

A standard hand-wash sampling technique was compared with a simple finger-streak sampling method in assessing the relative effectiveness of a number of alternative preparations used for disinfecting the surgeon's hands (alcoholic 0.5% chlorhexidine, alcoholic 0.1% tetrabrom-o-methyl phenol, a 4% chlorhexidine detergent solution, aqueous 0.5% chlorhexidine, 2% 'Irgasan' detergent solution and, as control, bar soap). There was a fairly good correlation between the results of assessment by the two methods after a single disinfection and after six disinfections, three on one day and three on the next. Significant differences were shown in 21 comparisons between treatments when the hand-wash sampling test was used, and 16 of these comparisons also showed a significant difference by the finger-streak test. Staphylococcus aureus was found in hand samplings from 5 out of 8 nurses in the Burns Unit of Birmingham Accident Hospital by the hand-wash sampling method and from 2 of the same 8 nurses by the finger-streak method; the numbers were small, and no Staph. aureus were isolated from the same hands after 1 min. wash in 70% ethyl alcohol. Similar sampling on 29 nurses in other wards showed Staph. aureus on 3 nurses (one in large numbers) by the hand-wash technique and on 1 nurse by the finger-streak test; in only 1 nurse whose hands showed Staph. aureus before disinfection was the organism found, by hand-wash sampling, after disinfection. Parallel sampling of nurses' hands after washing with soap and water and after disinfection with 95% ethanol showed larger numbers of Staph. aureus in a hospital for skin diseases than in a general hospital, and a lower incidence and somewhat lower density of Staph. aureus after ethanol treatment than after washing with soap and water; Gram-negative bacilli, on the other hand, were commoner on hands in the general than in the skin hospital, and present in much smaller numbers after disinfection with ethanol than after washing with soap and water. Antibiotic sensitivity tests showed the frequent recurrence on the hands of some nurses of multi-resistant Staph. aureus with resistance patterns similar to those found in infective lesions in some of the patients; different sensitivity patterns were usually found in staphylococci isolated from the nose. Even in wards where many patients were infected, carriage by nurses' hands of a particular strain of Staph. aureus did not seem to last for more than a few days.