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At least 19 recordsLinked to original sources

Use of germicides in the home and the healthcare setting: is there a relationship between germicide use and antibiotic resistance?

BACKGROUND: The spread of antibiotic-resistant pathogens represents an increasing threat in healthcare facilities. Concern has been expressed that the use of surface disinfectants and antiseptics may select for antibiotic-resistant pathogens. OBJECTIVE: To review the scientific literature on whether there is a link between use of germicides (ie, disinfectants and antiseptics) and bacterial resistance to antibiotics. In addition, we will review whether antibiotic-resistant bacteria exhibit altered susceptibility to germicides that are recommended for use as disinfectants or antiseptics. DESIGN: A review of the appropriate scientific literature. RESULTS: In the laboratory, it has been possible to develop bacterial mutants with reduced susceptibility to disinfectants and antiseptics that also demonstrate decreased susceptibility to antibiotics. However, the antibiotic resistance described was not clinically relevant because the test organism was rarely a human pathogen, the altered level of antimicrobial susceptibility was within achievable serum levels for the antibiotic, or the antibiotic tested was not clinically used to treat the study pathogen. Similarly, wild-type strains with reduced susceptibility to disinfectants (principally, quaternary ammonium compounds) and antiseptics (principally, triclosan) have been reported. However, because the concentration of disinfectants used in the healthcare setting greatly exceeds the concentration required to kill strains with reduced susceptibility to disinfectants, the clinical relevance of these observations is questionable. CONCLUSION: To date, there is no evidence that using recommended antiseptics or disinfectants selects for antibiotic-resistant organisms in nature. Disinfectants and antiseptics should be used when there are scientific studies demonstrating benefit or when there is a strong theoretical rationale for using germicides.

Anti-Bacterial Agents↗

Efficacy of hospital germicides against adenovirus 8, a common cause of epidemic keratoconjunctivitis in health care facilities.

The inactivation of virus-contaminated nonporous inanimate surfaces was investigated using adenovirus type 8, a common cause of epidemic keratoconjunctivitis. A 10-microl inoculum of adenovirus was placed onto each stainless steel disk (1-cm diameter), and the inoculum was allowed to air dry for 40 min. Twenty-one different germicides (including disinfectants and antiseptics) were selected for this study based on their current uses in health care. After a 1- or 5-minute exposure to 50 microl of the germicide, the virus-germicide test mixture was neutralized and assayed for infectivity. Using an efficacy criterion of a 3-log10 reduction in the titer of virus infectivity and regardless of the virus suspending medium (i.e., hard water, sterile water, and hard water with 5% fetal calf serum), only five disinfectants proved to be effective against the test virus at 1 min: 0.55% ortho-phthalaldehyde, 2.4% glutaraldehyde, 2.65% glutaraldehyde, approximately 6,000 ppm chlorine, and approximately 1,900 ppm chlorine. Four other disinfectants showed effectiveness under four of the five testing conditions: 70% ethanol, 65% ethanol with 0.63% quaternary ammonium compound, 79.6% ethanol with 0.1% quaternary ammonium compound, and 0.2% peracetic acid. Of the germicides suitable for use as an antiseptic, 70% ethanol achieved a 3-log10 reduction under four of the five test conditions. These results emphasize the need for proper selection of germicides for use in disinfecting noncritical surfaces and semicritical medical devices, such as applanation tonometers, in order to prevent outbreaks of epidemic keratoconjunctivitis.

Adenoviridae↗

Germicidal persistence of teat dips by modified excised teat procedure.

An excised teat protocol was modified to evaluate persistence of germicidal activity of teat dips over 8 h. Five teat dip formulations, iodophor (1%), chlorhexidine gluconate (.55%), linear dodecyl benzene sulfonic acid (1.94%), sodium chlorite-lactic acid in a water base, and sodium chlorite-lactic acid in a gel base were tested against Escherichia coli and Klebsiella oxytoca. Iodophor and chlorhexidine had high germicidal activity throughout 8 h, whereas dodecyl benzene sulfonic acid had little activity. Germicidal activity of both sodium chlorite-lactic acid teat dips was high initially but declined with time. The gel base dip, however, remained more germicidal than the water base dip. Results were similar for either organism for most teat dips. However, chlorhexidine was less effective and the gel base dip more effective against Klebsiella oxytoca than Escherichia coli. Standard errors often appeared higher for Klebsiella oxytoca than for Escherichia coli. These assays may prove useful for laboratory screening of teat dips to determine germicidal persistence over time.

Animals↗

Evaluation of postmilking teat germicides containing Lauricidin, saturated fatty acids, and lactic acid.

The efficacies of postmilking teat germicides containing Lauricidin (glyceryl monolaurate), saturated fatty acids, lactic acid, and lauric acid were determined against new IMI caused by Staphylococcus aureus and Streptococcus agalactiae in three controlled infection trials. In trial 1, a germicide was evaluated containing 1% Lauricidin, 5% caprylic and capric acids, 6% lactic acid, and .85% lauric acid. New IMI with Staph. aureus and Strep. agalactiae were reduced 81.3 and 49.6%, respectively. Trial 2 germicide involved an artificially aged sample of the formulation evaluated in trial 1. The germicide was aged at 40 degrees C for 5 mo, which was approximately equal to 2 yr at room temperature (24 degrees C). Reductions in new IMI were 81.2 and 27.5% for Staph. aureus and Strep. agalactiae, respectively. In trial 3, a teat germicide aged at ambient temperature for 33 mo, which was originally formulated to contain 1% Lauricidin, 5% caprylic and capric acids, and 6% lactic acid, was evaluated. Reductions in new IMI were 75.5 and 40.4% for Staph. aureus and Strep. agalactiae, respectively. The formulation evaluated in trial 1 was superior to other formulations in reducing new IMI by the two test organisms.

Animals↗

[Experiment observations of the germicidal effects of disinfectants on Vibro cholerae of El Tor biotype in different water bodies].

OBJECTIVE: To study the germicidal effect of disinfectant on vibro cholerae of El Tor biotype in different water bodies and to set a guidelines for disinfection in the epidemic foci of cholera. METHODS: The suspension quantitative bactericidal test was used to examine the germicidal effects of four kinds of disinfectants, including Chlorine compound disinfectant, Indophor, Chlorine dioxide and Glutarldehyde, on vibro cholerae of El Tor biotype in waste water from residential areas and hospitals, and water from ditches, rivers and seas. RESULTS: When germicidal rate for Vibrio Cholerae of El-Tor biotype in the five different kinds of water bodies reached to 100% in five minutes, concentrations of Chlorine compound disinfectant, Indophor, Chlorine dioxide and Glutaraldehyde were 25.0-250.0 mg/L, 100.0-250.0 mg/L, 10.0-25.0 mg/L and 100-500 mg/L, respectively. CONCLUSIONS: Germicidal effects of the four kinds of disinfectants on Vibrio Cholerae of El-Tor biotype differed, and so did germicidal effect of each of the same disinfectant on it in the five different kinds of water bodies. Concentrations of disinfectants needed to disinfected waste water was higher than that to disinfect natural water.

Chlorine Compounds↗

[Synergetic germicidal effect of ultrasonic with glutaraldehyde and its application in clinical disinfection].

OBJECTIVE: To study the synergetic germicidal effect of ulstrasonic with glutaraldehyde and the feasibility of combining ulstrasonic and glutaraldehyde to disinfect endocopes and medical instruments. METHODS: We determined the respective and the synergetic killing rates of Bacillus subtilis var. niger of ulstrasonic and glutaraldehyde using quantitative suspenion germicidal tests and simulated on-the-spot tests. RESULTS: In suspenion germicidal tests, because of the synergetic germicidal effect, the concentration of glutaraldehyde needed for sterilize spores was decreased from 20 mg/ml to 5 mg/ml for the same killing time(4 h), and when the concentrations were still 20 mg/ml, its killing time was shorten from 4 h to 1 h. Further more, the solutions containing 5 mg/ml glutaraldehyde could sterilize spores of Bacillus subtilis var. niger in 2 h. In the simulated on-the-spot tests, the concentration of glutaraldehyde needed for sterilization was decreased from 20 mg/ml to 5 mg/ml and its killing time was shorten from 4 h to 1 h under the synergetic germicidal effect. CONCLUSION: It indicats the feasibility of combining ulstrasonic and glutaraldehyde to disinfect instruments in clinic.

Bacillus subtilis↗

Experimental design and statistical analysis of an in-use test of germicidal detergents.

Present methodology for the in-use testing of germicidal detergents is too time-consuming for routine use by a hospital environmentalist. A simplified experimental design and statistical analysis, amenable to routine use, is presented for the in-use testing of germicidal detergents against water alone. As an illustration of our methodology we evaluated two germicidal detergents versus water alone. Under our conditions of use, it was found that water alone was equally and significantly as effective (p less than 0.001) as the two germicidal detergents in reducing microbial contamination of floors.

Anti-Infective Agents, Local↗

A disc-based quantitative carrier test method to assess the virucidal activity of chemical germicides.

Suspension tests for virucidal activity of chemical germicides are easier to perform, but they normally do not present the test product with a strong enough challenge. In contrast, carrier tests, where the test virus is dried on an animate or inanimate surface, offer the test formulation a higher level of challenge because it first has to penetrate successfully the inoculum to gain access to and inactivate the target organism on the carrier. Since pathogens in nature are normally found adsorbed to surfaces and/or embedded in organic or cellular debris, the results of carrier tests are more relevant to predicting the activity of chemical germicides under field situations. The method described below uses discs (1 cm in diameter) of brushed stainless steel discs as carriers. Ten micro l of the test virus in a soil load is placed on each disc and the inoculum dried under ambient conditions. The dried inoculum is then exposed to 50 micro l of the test formulation or a control solution for a defined contact time at the specified temperature. EBSS (0.95 ml) is added to each carrier holder to dilute/neutralize the germicide, the inoculum eluted and the eluates titrated in cell cultures to determine the degree of loss in virus viability. At least five test and three control carriers are used in each test. Controls are also included to test for toxicity of the test formulation to the host cells and any interference sub-cytotoxic levels of the formulation may have on the ability of the virus to infect the cells. The method has been used with several types of human and animal pathogenic viruses to test the activity of all major classes of chemical germicides against them.

Antiviral Agents↗

Efficacy of low-concentration iodophors for germicidal hand washing.

The efficacy of iodophor germicides containing different concentrations of available iodine against transient (inoculated) bacteria and the natural hand microflora was compared with chlorhexidine gluconate (2 and 4%) liquid detergent (Hibitane), non-germicidal soap and a tap water rinse. The tap water rinse was ineffective compared with all other treatments. Only 4% chlorhexidine gluconate liquid detergent and iodophor containing 0.75% available iodine were significantly better than the non-germicidal soap for reduction of transient bacteria, Escherichia coli and Pseudomonas fluorescens, that had been inoculated onto hands. These agents also caused a significant reduction in the number of 'natural' microorganisms released from hands after a standard 15 s hand wash. The low-concentration iodophor products and the product containing 2% chlorhexidine gluconate failed to give results significantly better than the non-germicidal control soap. Baird-Parker medium and standard aerobic plate counts were highly correlated (r = 0.82), so that for studies of Gram-negative bacteria inoculated onto hands as a transient microflora, counts on Baird-Parker medium give a reasonable indication of the natural (residual) hand microflora.

Chlorhexidine↗

The colonization of solid PVC surfaces and the acquisition of resistance to germicides by water micro-organisms.

Six common water bacteria were examined for their ability to colonize polyvinyl chloride (PVC) surfaces, survive various germicidal treatment, and re-establish themselves in sterile distilled water (SDW). For each test, two 30.4 cm PVC pipes attached to a 90 degrees PVC elbow were filled with 600 ml of distilled water inoculated with either Pseudomonas aeruginosa, Ps. cepacia, Ps. mesophilica, Acinetobacter anitratus, Mycobacterium chelonae or M. chelonae var. abscessus. After 8 weeks contaminated water was removed and the pipes were exposed to 600 ml of 1:213 iodophor disinfectant (ID), 1:128 phenolic detergent (P), 1:256 quaternary ammonium compound (QA), stock iodophor antiseptic (IA), 2% formaldehyde (F), 10-15 ppm free chlorine (C), 2% glutaraldehyde (G) and 70% ethanol (E). These germicides were periodically sampled, neutralized and examined for surviving organisms. After exposure for 7 d the germicides were removed and each pipe was refilled with SDW. This was assayed at 7 d intervals to determine microbial re-establishment. Samples were removed during microbial conditioning and examined by scanning electron microscopy (SEM). Pseudomonads were isolated directly from ID, QA, C, P and F, and mycobacteria from QA, IA, ID, P, G, C and F. Pseudomonas aeruginosa and Ps. cepacia survived in PVC pipes after 7 d of exposure to P, ID and C; Ps. mesophilica, after C and ID; and both mycobacteria, after C. SEM examination of PVC remnants revealed bacterial attachment and formation of extracellular material with embedded cells. These studies show that common water bacteria can attach and colonize the interior surface of PVC pipes and develop significant resistance to the action of certain germicides.(ABSTRACT TRUNCATED AT 250 WORDS)

Acinetobacter↗

Rapid screening method for Mycobactericidal activity of chemical germicides that uses Mycobacterium terrae expressing a green fluorescent protein gene.

The slow growth of mycobacteria in conventional culture methods impedes the testing of chemicals for mycobactericidal activity. An assay based on expression of the green fluorescent protein (GFP) by mycobacteria was developed as a rapid alternative. Plasmid pBEN, containing the gene encoding a red-shifted, high-intensity GFP mutant, was incorporated into Mycobacterium terrae (ATCC 15755), and GFP expression was observed by epifluorescence microscopy. Mycobactericidal activity was assessed by separately exposing a suspension of M. terrae(pBEN) to several dilutions of test germicides based on 7.5% hydrogen peroxide, 2.4% alkaline glutaraldehyde, 10% acid glutaraldehyde, and 15.5% of a phenolic agent for contact times ranging from 10 to 20 min (22 degrees C), followed by culture of the exposed cells in broth (Middlebrook 7H9) and measurement of fluorescence every 24 h. When the fluorescence was to be compared with CFU, the samples were plated on Middlebrook 7H11 agar and incubated for 4 weeks. No increase in fluorescence or CFU occurred in cultures in which the cells had been inactivated by the germicide concentrations tested. Where the test bacterium was exposed to ineffective levels of the germicides, fluorescence increased after a lag period of 1 to 7 days, corresponding to the level of bacterial inactivation. In untreated controls, fluorescence increased rapidly to reach a peak in 2 to 4 days. A good Pearson correlation coefficient (r > or =0.85) was observed between the intensity of fluorescence and the number of CFU. The GFP-based fluorescence assay reduced the turnaround time in the screening of chemical germicides for mycobactericidal activity to < or =7 days.

Anti-Bacterial Agents↗

[In vitro germicide action of disinfectant products used in the food industry].

There is a wide offer of disinfectant products, for the food industry, available in the market, such as chlorine, iodine and quaternary ammonium compounds and their respective derivatives. However, new alternative products have emerged, for instance grapefruit seed extract, and peracetic and lactic acids. The present study was carried out in order to analyze in vitro the germicide effect, from the grapefruit seed extract (400 ppm), peracetic acid (2000 ppm) and lactic acid (20,000 ppm) at the manufacturer recommended action time, and other additional times. The germicide effect was tested against microorganisms such as Escherichia coli, Staphylococcus aureus, Streptococcus faecalis and Pseudomonas aeruginosa. In each case, the death kinetic was determined through the evaluation of the germicide effect (%), specific death rate (t-1) and the decimal reduction time (min). From the evaluated products, the best germicidal effect at the manufacturer conditions was reached by peracetic acid (2000 ppm) at 1 min, which presented the lower decimal reduction times compared with the other tested microorganisms. Generally speaking, Gram positive microorganisms showed a greater sensibility to the disinfectant action.

Disinfectants↗

Monitoring human exposures to upper-room germicidal ultraviolet irradiation.

After decades of neglect, the resurgence of tuberculosis in the United States between 1985 and 1992 renewed interest in the use of upper room ultraviolet germicidal irradiation to interrupt the transmission of airborne infections. More recently the bioterrorism threat and the appearance of new pathogens with the potential for airborne spread, such as severe acute respiratory syndrome (SARS), have stimulated installations of upper-room irradiation systems. The objective is to flood the entire volume of a room above 6.5 ft with high intensity ultraviolet germicidal irradiation, while minimizing unintentional irradiance below 6.5 ft to avoid eye and skin irritation. Air exchanges between the upper and lower room result in air disinfection of the occupied space. Designers of these systems have adopted the practice of limiting the maximum lower room irradiance at every point to less than the continuous 8-hour time-weighted average threshold limit value, severely limiting the irradiation intensity in the upper room and thereby reducing one of the two major factors determining germicidal effectiveness, the other being room air mixing. The hypothesis of this study is that eye and skin exposure will be well below the recommended safe dose even when maximum eye-level irradiance levels in the room exceed the 8-hour continuous exposure threshold limit. The method employed was to have subjects wear a small photometer that recorded total ultraviolet dose over the period of exposure while subjects went about their normal routine, and comparing this value with a hypothetical dose calculated from the highest measured eye-level irradiance. The results of the study, based on a limited number of observations, confirmed the hypothesis. Observed doses were one-third to a factor of a hundred or more lower than the doses calculated from maximum eye-level irradiances measurements in the occupants' spaces.

Bioterrorism↗