Ineffective Disinfection Research Articles

Bacterial contamination on clinical surfaces and oxygen device accessories in the emergency unit of a tertiary health facility in Ghana

BackgroundNosocomial infections have gradually become an emerging threat to the healthcare system over the past decades and have been attributed to poor decontamination of hospital articles and weak antibacterial stewardship policies. This study sought to investigate the effect of disinfection on the prevalence and resistance profile of bacterial contaminants on oxygen device accessories, and clinical surfaces at the emergency unit of a tertiary health facility in Ghana.MethodsThe study employed a cross-sectional study design to evaluate the occurrence of bacteria on surfaces in a tertiary hospital. Luminal swabs of the oxygen device accessories and swabs from clinical surfaces used by healthcare providers were collected for isolation and identification of bacteria. The identified bacteria isolates were then tested for their susceptibility to antibacterial agents. Data from this study were analyzed using Excel (Microsoft Office Suite), and GraphPad Prism 8 software programs.ResultsA quarter of the total 44 bacterial isolates obtained from both post-disinfected and pre-disinfected surfaces were Gram-positive, with the remaining isolates being Gram-negative. Pseudomonas aeruginosa was the most frequent bacteria species isolated (41%) followed by Citrobacter sp. (21%). P. aeruginosa, S. aureus, and S. pneumoniae were found to be highly resistant to Chloramphenicol (36%), and Sulfamethoxazole (100%); whereas Ciprofloxacin (91%) was the most effective antibacterial drug used.ConclusionThe almost equal prevalence of multidrug-resistant bacteria from both post-disinfected and pre-disinfected surfaces of inanimate objects, and oxygen device accessories connote an ineffective disinfection process which may influence resistance in bacterial contaminants. This requires the overhaul of disinfection protocol and training of hospital staff, and rational use of antibacterial agents at the hospital to mitigating the burden of nosocomial infections.

Novel anti-Acanthamoebic properties of raloxifene sulfonate/sulfamate derivatives

Acanthamoeba are known to cause a vision threatening eye infection typically due to contact lens wear, and an infection of the central nervous system. The ability of these amoebae to switch phenotypes, from an active trophozoite to a resistant cyst form is not well understood; the cyst stage is often resistant to chemotherapy, which is of concern given the rise of contact lens use and the ineffective disinfectants available, versus the cyst stage. Herein, for the first time, a range of raloxifene sulfonate/sulfamate derivatives which target nucleotide pyrophosphatase/phosphodiesterase enzymes, were assessed using amoebicidal and excystation tests versus the trophozoite and cyst stage of Acanthamoeba. Moreover, the potential for cytopathogenicity inhibition in amoebae was assessed. Each of the derivatives showed considerable anti-amoebic activity as well as the ability to suppress phenotypic switching (except for compound 1a). Selected raloxifene derivatives reduced Acanthamoeba-mediated host cell damage using lactate dehydrogenase assay. These findings suggest that pyrophosphatase/phosphodiesterase enzymes may be valuable targets against Acanthamoeba infections.

Microbiological Profile of Primary Teeth with Irreversible Pulpitis and Pulp Necrosis with/without Abscess and their Susceptibility to Three Antibiotics as Intracanal Medication.

The ineffective disinfection potential of conventional intracanal medicaments to eliminate enteropathogens from root canal systems leads to their persistence contributing to endodontic treatment failures. Hence, the use of appropriate intracanal medicament becomes the essential phase to accomplishing comprehensive decontamination of the root canal system. When applied topically as an intracanal medicament, antibiotics eradicate residual microorganisms from tortuous endodontic spaces, minimizing the risk of systemic toxicity. To evaluate the prevalence of various bacterial species associated with signs of irreversible pulpitis and pulp necrosis with/without abscess in primary teeth root canals and their susceptibility against three antimicrobial agents. The pulp tissue and organic debris were retrieved from deciduous teeth (n = 50) from children between the age of 3-10 years and cultured. The bacterial identification and antibacterial profiling of isolated bacteria were done against clindamycin, metronidazole, and doxycycline through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assay. The MIC and MBC of each antibiotic were expressed as mean ± standard deviation (SD), range, and standard error (SE of the mean). The intergroup comparisons were done by the Kruskal-Wallis test, while intragroup pair-wise comparisons were done using the Wilcoxon signed-rank test. The confidence level will be set at 95%. Aerobic bacteria were found in 54%, microaerophilic bacteria in 76%, facultative anaerobes in 26%, and obligatory anaerobes were isolated from 30% of teeth. The intragroup and intergroup comparisons of test agent MIC revealed a nonsignificant difference (p > 0.05). The intragroup MBC comparisons of all the test agents revealed statistically nonsignificant (p > 0.05), while intergroup comparisons demonstrated nonsignificant (p > 0.05) to highly significant difference (p < 0.001). Clindamycin demonstrated promising antibacterial activity against most of the isolated bacteria, while against metronidazole and doxycycline, most of the bacteria were moderate to highly resistant. Determining the antibacterial agents' efficacy along with modifications can help to target maximum pathogenic microbes and reduce catastrophic endodontic therapy failures. Dahake PT, Kothari S. Microbiological Profile of Primary Teeth with Irreversible Pulpitis and Pulp Necrosis with/without Abscess and their Susceptibility to Three Antibiotics as Intracanal Medication. Int J Clin Pediatr Dent 2023;16(2):312-320.

Susceptibility of Clostridium sporogenes Spores to Selected Reference Substances and Disinfectants.

Research on the susceptibility of the spores of anaerobic bacteria such as Clostridium sporogenes or Clostridioides difficile is vital for assessing the sporicidal activity of disinfectants. The diverse susceptibility of anaerobic bacteria spores may lead to different disinfection parameters being determined by laboratories that prepare spore suspensions to test sporicidal effectiveness. The tests were performed using the suspension method according to PN-EN 13704:2018-09. In order to assess the susceptibility of the C. sporogenes spores, the criterion established for the C. difficile ribotype 027 spores was used in accordance with PN‑EN 17126:2019-01. The susceptibility of the C. sporogenes spores to glutardialdehyde corresponded to the susceptibility ranges established for the C. difficile ribotype 027 spores. The C. sporogenes spore suspension was susceptible to low concentrations of peracetic acid (0.01%). A disinfectant containing peracetic acid as the active substance showed high sporicidal activity at a low concentration (1%), a short contact time (15 minutes), and a high organic load (3.0 g/l bovine albumin + 3.0 ml/l sheep erythrocytes), as compared to a disinfectant with glutardialdehyde, which was sporicidal at a higher concentration (2.5%), at a longer contact time (60 minutes) and lower organic conditions (3.0 g/l bovine albumin). There is a need to define the minimum susceptibility criteria for the C. sporogenes spores to the reference substances most often found in disinfectants with sporicidal activity. Excessive susceptibility of the C. sporogenes spores to reference substances may result in low-performance parameters of disinfection products with sporicidal activity and lead to ineffective disinfection in practice.

Assessment of the prevalence of Pseudomonas aeruginosa among Iraqi patients with acne and study of their antibiotic susceptibility patterns

Background: Pseudomonas aeruginosa is found in soil and water all over the world. It prefers moist areas, such as wash basins, toilets, and swimming pools that are insufficiently chlorinated, and expired and ineffective disinfection solutions. Pseudomonas aeruginosa infections range from external infections such as acne. A simple, severe, life-threatening disorder that is highly antibiotic-resistant. Aims: The current study was undertaken to analyze the frequency of P. aeruginosa as a microbial skin infection patient with acne and study their antibiotic sensitivity patterns due to a rise in instances of acne among young people in Iraq. Methods: A total of 61 samples were taken from inflamed and pus discharge patients,27 males and 34 females, with acne vulgaris on the face. Samples were cultured on selective, enrichment, and special media then incubated for 18-24 hr. at 37 °C. Bacterial Isolates Identification was done using different culture media, Microscopic Examination with Gram stain, in addition to Biochemical tests. In addition to API 20E identification system and conformation by VITEK 2 compact system. Antibiotic susceptibility test is done using different antibiotics. Results: Pseudomonas aeruginosa isolates were found in 23 (37.70%)/ 61 of the samples, with 11 (47.83%) male and 12 (52.17%) female.

Transmission of Pan-resistant and Echinocandin-resistant Candida Auris Between Healthcare Facilities During the COVID-19 Pandemic

BackgroundCandida auris is a Texas notifiable condition requiring isolate submission to the state public health laboratory. C. auris spreads in healthcare through contact with contaminated surfaces and unclean hands. During the COVID-19 pandemic, pan-resistant and echinocandin-resistant C. auris were identified in Texas for the first time.MethodsIn January 2021, a long-term acute care hospital patient's isolate was identified as C. auris. Retrospective surveillance identified a 2020 case. Remote and onsite infection control assessments (ICARs) were conducted at healthcare facilities (HCFs) where the cases received care. Colonization screenings were conducted until the HCFs achieved two rounds of negative results. Cases and those pending screening results were placed on contact precautions. Epidemiologists provided education and resources to HCFs to mitigate identified infection prevention gaps. Antifungal susceptibility testing (AST) was performed at the Antibiotic Resistance (AR) Laboratory Network laboratory. Whole genome sequencing (WGS) was performed by the Centers for Disease Control and Prevention (CDC) Laboratory.ResultsThere were 47 C. auris cases with collection dates from November 20, 2020, to September 27, 2021, including 15 clinical and 32 colonized cases from 22 years to 89 years old with a mean age of 63. Sixty-six percent (n=31) were males. Common gaps from the 46 ICARs conducted at 42 HCFs included using ineffective disinfectants, not following manufacturer's instructions, reusing disposable personal protective equipment, and not conducting audits. There were 59 colonization screenings at 20 HCFs. AST revealed two pan-resistant, seven echinocandin-resistant, and thirty-one fluconazole resistant cases. CDC performed WGS on 16 isolates, revealing clusters within and between HCFs, including a cluster of resistant cases.ConclusionsWGS supported transmission of pan-resistant or echinocandin-resistant C. auris for the first time in the United States. The pandemic presented new infection control risks. Rapid surveillance detection, colonization screenings, infection control assessments, and education are instrumental to outbreak containment.

Anaemia in Lambs Caused by Mycoplasma ovis: Global and Australian Perspectives.

Simple SummaryMycoplasma ovis (formerly Eperythrozoon ovis) inhabits red blood cells and may cause their destruction, leading to anaemia, jaundice and death mainly in lambs, and condemnation of jaundiced carcases at abattoirs. Mycoplasmosis is spread during high-risk procedures that expose or share blood, especially when blood sucking flies and other insects are present on wounds that transfer infection. High-risk procedures include vaccination (re-use of needles), ear-tagging (ineffective disinfection), surgical castration and mulesing (in Australia), and potentially crutching and shearing, with outbreaks usually occurring up to 6 weeks later. Affected animals are weak, lagging in the ‘tail of the mob’ and collapsing when mustered. The investigation of other causes of anaemia and jaundice is required, particularly haemonchosis (Barbers pole worms) and malnutrition. The diagnosis involves the demonstration of M. ovis in blood smears and/or by PCR, although the absence of the parasite in smears from affected animals requires the examination of in-contact healthy animals. Treatment with antibiotics is ineffective. For its control, it is required that risky procedures are avoided during high insect activity and the yarding of stock within the next 6 weeks is minimised. Recent anecdotal observations suggest that improved farm practices, including fly control and pain/antiseptic wound dressing may potentially decrease M. ovis risk on some farms in some areas of Australia.Mycoplasma ovis (formerly Eperythrozoon ovis) is a haemotropic parasitic bacterium found within erythrocytes and distributed widely in global sheep and goat production regions. M. ovis is transmitted by biting flies and by contaminated instruments, causing morbidity and mortalities from anaemia, usually within 6 weeks following blood-exposure procedures, particularly vaccination, castration, ear tagging, mulesing, and occasionally crutching and shearing. Affected animals develop haemolytic anaemia and may have jaundice, causing abattoir condemnations. The typical history, clinical and pathological findings, display of M. ovis in blood smears and/or by PCR is diagnostic, although immune responses deplete M. ovis from smears; hence, in-contact healthy animals should be examined. Differential diagnoses include haemonchosis, fasciolosis, malnutrition (copper or vitamin B12 deficiency), and plant toxicities. M. ovis parasitaemia may persist, with recrudescence following stressful events, although most older sheep remain immune. Human infections have been reported. Inadequate socioeconomic data present difficulties in assessing the impact of M. ovis on production and as antimicrobial therapy is ineffective, its control requires management practices that minimize the impact of invasive procedures in periods when risks of M. ovis transmission are more likely. Although considered an emerging pathogen, recent improvements in welfare attitudes and husbandry practices on Australian sheep farms may potentially limit the transmission of M. ovis.

EXPERIMENTAL JUSTIFICATION OF THE EFFICIENCY OF BIOLIDE DISINFECTANT FOR DISPOSAL OF BACTERIAL INFECTIONS IN CONDITIONS OF INDUSTRIAL POULTRY

The materials of the article are devoted to the study of the bactericidal action of the newly developed «Biolaid» disinfectant at the first stage to determine the possibility of its use in the poultry industry to replace expensive, often toxic and ineffective disinfectants that have now flooded the market in Ukraine.&#x0D; Modern poultry farms are integrated enterprises, the structure of which consists of one continuous link with an incubator, own parent and industrial herds, production shops for processing products and feed production. One of the most important factors in the successful operation of such enterprises is quality disinfection.&#x0D; The problem of developing new cheap, safe, effective disinfectants remains relevant. The problem is supplemented by questions on the study of the effects of disinfectants on the indicators of general resistance in poultry and their impact on the productivity of birds, as such information is quite limited.&#x0D; Bacterial suspensions of test cultures with a concentration of 0.5–1.0 according to the McFarland standard (microbial load from 1.35×108 to 3.0×108 CFU/cm3) were prepared for the study by washing the colonies of the daily culture of microorganisms with trypton-soy agar (TCA) with sterile saline. The working dilutions of the experimental disinfectant were made according to the recommendations in the leaflet-tab, in concentrations of 0.1; 0.2; 0.25 and 0.5 % at exposures of 10, 20 and 30 minutes.&#x0D; The results of studies of the newly developed «Biolaid» disinfectant showed its high efficiency, proven experimentally, because at the level of 0.25 % concentration of the working dilution of the drug at an exposure of 30 minutes. complete neutralization of test cultures of Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 15442 was achieved without bacteriostatic effect, which testified to the effectiveness of the drug in its action on gram-negative and gram-positive pathogenic bacteria.

Evaluation of the Antimicrobial Efficacy of Elettaria cardamomum Oil, Trachyspermum ammi Oil and 5% Sodium Hypochlorite Against Enterococcus faecalis Biofilm Formed on Tooth Substrate

Context:The usual cause of nonfulfillment of endodontic therapy is the persistence of microorganisms in the root canal system due to ineffective disinfection. Enterococcus faecalis is one of the most prevalently isolated microorganisms following a failure in root canal treatments. Sodium hypochlorite is among the most effectively used irrigant solutions but has many shortcomings. Herbal alternatives for sodium hypochlorite might prove to be superior due to their high antimicrobial activity, biocompatibility, and their antioxidant and anti-inflammatory properties.Aims:This study is aimed to evaluate the antimicrobial efficacy of Trachyspermum ammi oil and Elettaria cardamomum oil against 2-week-old and 4-week-old E. faecalis biofilms formed on tooth substrate.Settings and Design:A pure culture of E. faecalis was grown on brain heart infusion agar, inoculated into brain heart infusion broth, and incubated at 37°C overnight. Single rooted human mandibular premolars were sectioned below cementoenamel junction, enlarged, and vertically sectioned along the midsagittal plane. The samples were then placed in tissue culture wells inoculated with 2 ml of the bacterial solution and incubated at 37°C.Materials and Methods:Group 1 E. cardamomum oil (cardamom), Group 2 T. ammi oil (ajwain), Group 3 5% sodium hypochlorite, and Group 4 Saline (control) (n = 10). At the end of the 2nd and 4th weeks, all groups were treated for 10 min with 3 ml of the respective solutions. Quantitative analysis was performed by serial dilution.Results:T. ammi oil and sodium hypochlorite treated teeth showed complete elimination of both the 2-week-old and 4-week-old E. faecalis biofilm. Meanwhile, saline and E. cardamomum oil-treated teeth still showed the presence of E. faecalis.Conclusions:The use of T. ammi oil as a root canal irrigant solution can be considered as an alternative to sodium hypochlorite.

Evaluation of the effectiveness of disinfection in dog shelter

Cleaning and disinfection are among the most important tasks in shelters and an important link in the prevention and battle against infectious diseases. Inadequate cleaning and ineffective disinfection can spread the disease to animals in the surrounding pens or to people during their daily contact and care of the animals. It is important to follow the order of the individual steps performed during hygiene procedures and carry out subsequent control of their efficacy. The aim of this study was to evaluate the effectiveness of disinfection by means of swabs taken from selected surfaces in a dog shelter – Happy dog, located in eastern Slovakia. The surfaces were disinfected with Savo Prim contains active substance sodium hypochlorite and anionic surfactant. For good cleaning effect was added disinfectant in a ratio of 1:5 to hot water at a temperature of 50°C and sprayed under pressure of 50 Bar. The effectiveness of mechanical cleaning followed by disinfection was evaluated by microbiological swabs from watering and food bowls, wall and floor. Swabs were taken before and after mechanical cleaning and disinfection, from 10cm2 areas. The surface area was wiped with a sterile cotton swab, the swab was placed in a sterile tube with 10ml of sterile saline solution and 0.1ml from this mixture was applied to Endo agar and meat peptone agar. Swabbing of the disinfected surfaces showed a significant decrease in TCB (total count of bacteria) and CB (coliform bacteria). However, on the walls and floors were detected small count of TCB and CB after disinfection in comparison with the counts detected before cleaning but the number of indicator bacteria was below the recommended value. Based on these observations, we can evaluate the hygienic program with the disinfection performed in the shelter as sufficient.

Design and implementation of the infection prevention program into risk management: Managing high level disinfection and sterilization in the outpatient setting.

Reusable, invasive medical devices within the outpatient setting pose a risk for patient harm. Ineffective disinfection of medical devices can potentially lead to transmission of pathogens between patients; and improper handling can lead to patient injury. A risk assessment was conducted, and the results strongly supported the necessity to develop a robust infection prevention program within the risk management department. This exclusive program was a proactive approach to preventing patient exposure within our healthcare system. Designing and integrating an Infection Prevention program into the Risk Management Department presented challenges, especially with the magnitude of devices and lack of standardization throughout our 33 clinics. Key components of the program included: capturing an accurate inventory of devices throughout the system, hiring a sterile processing expert, engaging support from senior leadership, adhering to rigorous auditing processes, and establishing a staff competency training structure. Since the program was launched 2 years ago, outcomes include: identification of high-risk practices with immediate resolution, increase in average clinic compliance to device reprocessing standards from 88% to 99%, elimination of 71% of scope reprocessing and 39% of instrument sterilization by clinic staff with allocation to central sterile processing departments, and development of a staff competency training structure.

Salmonella Infantis in Broiler Flocks in Slovenia: The Prevalence of Multidrug Resistant Strains with High Genetic Homogeneity and Low Biofilm-Forming Ability.

For almost a decade, the number of Salmonella enterica subspecies enterica serovar Infantis-positive broiler flocks has been steadily increasing in Slovenia, doubling the number of positive holdings in only a few years. Since multidrug resistant S. Infantis isolates are highly prevalent in the broiler meat industry and may represent a public health concern through the food chain, we aimed to investigate the antimicrobial susceptibility, genetic diversity, and biofilm-forming ability of S. Infantis from Slovenian broiler flocks. A total of 87 S. Infantis strains isolated from broiler faeces in the period between 2007 and 2013 were studied. The samples originated from 41 farms which were subcontractors of three major food business operators and from two autonomously operating holdings (farms). Isolates were phenotypically tested for their susceptibility to 14 antimicrobials from nine classes by determining the minimum inhibitory concentration with the microdilution method. Only 8% of the isolates were susceptible to all of the antimicrobial agents tested, while 88.5% of the isolates were multidrug resistant, with the most common resistance pattern CipNxSSuT (65.5%) followed by CipNxSuT (17.2%). Pulsed-field gel electrophoresis (PFGE) divided the strains into five clusters (A-E) comprising 16 distinct XbaI PFGE profiles. Sixty-five out of 87 isolates were grouped in clusters A and B, with the predominant PFGE profiles A1 and B1 encompassing 33 and 28 isolates, respectively. A vast majority of the isolates (75/87) showed >90% PFGE profile similarity. The biofilm-forming capacity of the tested isolates, determined with crystal violet assay in polystyrene microwell plates, was generally weak. The average biofilm formation for persistent strains was higher than for presumably nonpersistent strains; however, the difference was not significant. It seems that S. Infantis persistence on broiler farms is more related to its widespread occurrence in the broiler production chain and ineffective disinfection protocols than to its ability to form biofilm.

How Can We Ensure Water Mains Will Pass Bacteriological Tests?

Many factors in a pipeline installation can cause contamination and ineffective disinfection. However, carefully following all basic precautions will result in the highest possible passing percentage.

Potential for nosocomial transmission of Enterococcus faecalis from surfaces in dental operatories.

To assess the potential for nosocomial transmission of Enterococcus faecalis during root canal treatment by measuring its occurrence on surfaces in dental operatories in relation to the efficacy of disinfection routines. Eight dental clinics (two endodontic specialist clinics and six general dentistry clinics) were included. Bacterial sampling was conducted in duplicate after root canal treatment and collected before and after disinfection from four surfaces expected to be frequently disinfected and six surfaces expected to be occasionally disinfected. A total of 320 samples were collected. Overall, 40.6% (n = 130) exhibited bacterial growth, mostly consisting of environmental bacteria (36.3%) and to a lesser extent of bacteria from salivary contamination (3.4%). Only three surfaces, all of which were probably seldomly disinfected, were positive for E. faecalis (0.9%). Disinfection routines resulted in an increased contamination in the majority of general dentistry clinics: 64% (32/50) of the surfaces were contaminated prior to and 70% (35/50) after disinfection. Conversely, disinfection of surfaces in the specialist clinics reduced contamination levels by 10%. The origin of E. faecalis in secondary root canal infections remains unclear, as the potential for nosocomial transmission of enterococci from environmental surfaces in dental surgeries appears to be very small. The incorrect or ineffective disinfection procedures in general dentistry clinics needs to be addressed to counteract the risk for bacterial transmission in dental operatories.

Antimicrobial Irrigants in Endodontic Therapy. 2: Clinical Tips for Isolation and Irrigant Use.

This second article will concentrate on the clinical use of root canal irrigants, highlighting why commonly used techniques may be suboptimal and result in ineffective disinfection during endodontic therapy.

Contamination of bottles used for feeding reconstituted powdered infant formula and implications for public health

Microbial contamination of powdered infant formula (PIF) is known to cause gastrointestinal infections in infants. Of concern is intrinsic contamination of the formula with (for example) Salmonella enterica as well as extrinsic contamination from inappropriate handling or ineffective disinfection. The aim of this study was to evaluate organic and microbial contamination of 'in-use' bottles used for feeding infants powdered formula milk in South Wales, UK. To establish baseline contamination levels of 'in-use' bottles, 75 'uncleaned' and 150 'cleaned and ready to re-use' bottles used for feeding infants PIF were analyzed. The microbiological analysis included aerobic colony counts (ACCs), presence/absence and counts of Enterobacteriaceae and Staphylococcus aureus. The level of residual adenosine tri-phosphate (ATP) was determined as an indicator of organic soiling. All bottles were sampled in four sites; inner screwcap, bottle interior; bottle outer rim and teat interior. Microbial counts up to 10(5)/area were sampled and ATP levels up to 100,051 relative light units (RLUs) were obtained from 'uncleaned' bottles. Findings varied according to bottle site. Enterobacteriaceae and Staphylococcus aureus were isolated from 12-15% of 'unclean' bottles/components (up to 10(2) cfu/area sampled) and contamination was most frequently detected from the screw cap and teat interiors. Data indicated that after use, prior to cleaning, considerable microbial and organic soil remained in the cumulative bottles. Of the ready-to-use bottles reportedly cleaned and disinfected, some had ACCs up to 5.8 x 10(4) cfu/area sampled. Staphylococcus aureus was detected from 4% bottles/components but no Enterobacteriaceae were detected. Cumulatively, findings indicate the presence of organic soiling and the potential for survival of bacteria between infant feeds. There is a need for effective education on effective bottle decontamination procedures. This may be achieved by using an audience-centred approach to re-enforce messages to parents and caregivers to implement good hygiene practices, effectively wash and rinse items before disinfection and follow manufacturers' guidelines for disinfection.

Registration of disinfectants based on relative microbicidal activity.

Along with proper hand hygiene, disinfection of contaminated surfaces and medical instruments has been a key method of preventing patient-to-environment-to-patient transmission of infectious agents via the hands of healthcare workers.1-3 However, there is growing concern regarding the increase in antibiotic-resistant pathogens for which environmental and device contamination may play a role in disease transmission, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), Clostridium difficile, and multidrugresistant aerobic gram-negative bacilli (eg, Pseudomonas aeruginosa and Acinetobacter).1 Proper use of disinfectants plays an important role in reducing person-to-person transmission of these pathogens. For decades, the medical community in the United States has relied on the federal government’s disinfectant testing and registration program for assurance that registered disinfectants meet their label claims. However, recognized flaws in test methodologies could result in registration of ineffective disinfectants.4 Control measures should be instituted at the federal level to improve the test methodology and reduce the frequency of contaminated or ineffective disinfectants and the threat of serious healthcare-associated infections related to disinfectant use. We have previously reviewed the issues surrounding the selection and registration of high-level disinfectants and chemical sterilants.5 However, there are several unique aspects of testing and registration of low-level and intermediate-level disinfectants (eg, microbicidal testing methods) that warrant separate discussion. This article proposes a scheme for testing and registration of low-level and intermediate-level disinfectants that could be used by the U.S. Environmental Protection Agency (EPA). BACKGROUND Chemicals formulated as disinfectants in the United States are registered and regulated in interstate commerce by the Antimicrobial Division, Office of Pesticides Program, EPA. The authority for this activity was mandated by the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) in 1947. In June 1993, the U.S. Food and Drug Administration (FDA) and the EPA issued a “Memorandum of Understanding” that divided responsibility for review and surveillance of chemical disinfectants between the two agencies. Under the agreement, the FDA regulates disinfectants used on critical or semicritical medical devices and antiseptics and the EPA regulates disinfectants used on noncritical surfaces. In 1996, Congress passed the Food Quality Protection Act (FQPA). The Act amended FIFRA regarding several products regulated by both the EPA and the FDA. One provision of FQPA is that regulation of disinfectants used on critical and semicritical medical devices (the EPA continues to regulate non-medical disinfectants) was removed from the jurisdiction of the EPA and now rests solely with the FDA.1,6 Examples of disinfectants that are registered by the EPA with the intent of providing a public health benefit, therefore requiring efficacy data as a condition of their registration, include disinfectants used in hospitals and other healthcare settings on floors, walls, and medical equipment surfaces and household products claiming to have disinfectant activity. There are three types of disinfectant products that the EPA registers based on submitted efficacy data: limited, general or broad-spectrum, and hospital disinfectants. When a disinfectant is represented in its labeling for use in hospitals, medical clinics, dental offices, or any other medical-related facility, it must show

The possible effect of a sanitization program on intraspecies differentiation of Listeria monocytogenes strains isolated from a fish processing plant

Forty-seven Listeria monocytogenes strains isolated during a year in a selected Polish fish-processing plant as well as 7 L. monocytogenes strains of different origins (including a reference strain) were analyzed in our studies. Strains were isolated from raw fish fillets (flounder), frozen coated flounder fillets, coating ingredients, and the processing environment. Isolation of strains covered the period of a sanitization program introduced in the plant. L. monocytogenes was identified using conventional microbiological methods and the PCR technique. RAPD (random amplified polymorphic DNA) technique for fingerprinting was applied to analyze the intraspecies diversity. Six RAPD types (A – F) and seven unique strains were revealed as a result of fingerprinting with one persistent type isolated from July 1999 to February 2000. It was detected for the first time after one month of sanitization. Its occurrence could have been promoted by clone selection either due to ineffective disinfection or to resistance against the disinfectant. As L. monocytogenes mostly occurred on frozen products, this indicates that contamination could start during product freezing, cold storage, or handling. The results revealed that there is a crucial need for preparing sanitization schemes precisely targeted at L. monocytogenes to avoid its recurrence as persistent ‘in – house' strains. The possibility of incorrect interpretations of classical microbiological test results as well as the necessity to introduce assays based on nucleic acid analysis into epidemiological investigations were emphasized.

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.

Efficacy of Chemical Sterilants/Disinfectants Is There a Light at the End of the Tunnel?

Chemical sterilants/disinfectants are used to sterilize or disinfect instruments that cannot tolerate autoclave or gas sterilization. The Environmental Protection Agency (EPA) registers and approves these products for use. Registration is based on approval of data supplied by each manufacturer purporting to prove the efficacy of the product. As described in three previous articles by this author, these claims of efficacy are in question.1-3 Prior to 1982, the conducted limited testing of sterilants, and up to 30% of products failed these verification tests. Since 1982, no tests on manufacturers' claims have been performed by the EPA. Since 1982 and before, independent labs have disputed some of the claims, and the reported inconsistencies in performance have greatly worried infection control personnel. As a result, hearings were conducted by congressional committees, and the conclusions have been reported by the United States General Accounting Office.4 That report states that the EPA does not know whether disinfectants kill the germs claimed on product labels, and the extent to which ineffective disinfectants are marketed (with registration) is unknown.... Evidence exists that some registrants have submitted to the efficacy test data indicating that their disinfectants work, but have withheld other test data indicating that these disinfectants do not work as claimed.