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Changes in serum pneumoproteins caused by short-term exposures to nitrogen trichloride in indoor chlorinated swimming pools.

Nitrogen trichloride (NCl(3)) is an irritant gas released in the air of indoor pools sanitized with chlorine-based disinfectants. In the present study we investigated the effects of NCl(3) on the pulmonary epithelium of pool attendees by measuring the leakage into serum of three lung-specific proteins (pneumoproteins): the alveolar surfactant-associated proteins A and B (SP-A and SP-B) and the bronchiolar 16 kDa Clara cell protein (CC16). These pneumoproteins were measured in the serum of 29 recreational swimmers (16 children and 13 adults) before and after attending a chlorinated pool with a mean NCl(3) concentration of 490 microg m(-3). Pneumoprotein changes in serum were also studied in 14 trained swimmers performing an intensive 45 min standardized swimming session in a chlorinated pool (mean NCl(3) concentration of 355 microg m(-3)) and for the purposes of comparison in a non-chlorinated pool sanitized by the copper/silver method. Serum CC16 was not increased in recreational swimmers, but in trained swimmers serum levels of this protein peaked immediately after strenuous exercise, both in the copper/silver pool and in the chlorinated pool. This acute increase in airway permeability is probably the consequence of the mechanical stress on the epithelial barrier caused by overinflation and/or hyperventilation during intense exercise. Serum levels of SP-A and SP-B were unaffected by strenuous exercise in the copper/silver pool. The two proteins were, however, significantly increased in a time-dependent manner in recreational and trained swimmers attending the chlorinated pool. The intravascular leakage of SP-A and SP-B was already statistically significant after only 1 h of exposure to pool air without exercising and remained elevated for 12 h after. These changes were not associated with decrements in lung function. The ability of NCl(3) to acutely disrupt the lung epithelium barrier was confirmed in mice using serum CC16 and plasma proteins in bronchoalveolar lavage fluid as permeability markers. The significance of these permeability changes induced by NCl(3) in the deep lung is presently unknown. In view of the increasing and widespread human exposure to this gas not only in indoor pools but also in a variety of other situations, these findings warrant further study.

Adolescent↗

2nd World Water Forum.

The world is facing a water crisis. About one billion people lack access to safe water and three billion to appropriate sanitation. There will probably be two billion extra people on the planet by 2025; so while today's shortages are for fresh water and sanitation, tomorrow's are predicted to be for growing crops. Already, 10% of world food production is drawing down underground water faster than the recharge rates. Water also threatens to cause conflicts between regions--a state of affairs that is expected to worsen as this century progresses. To raise public awareness of these issues and pressurize politicians to act, the World Water Commission (WWC) held a Forum in March 2000 in The Hague. The Forum collected together a huge range of people from governments, non-government organizations (NGOs), workers for the environment and development, private sector water providers, trades unions and scientific institutes. They all discussed a document (World Water Vision: A Water Secure World, referred to as the Vision) drawn up by the WWC as a basis for action. The Forum culminated in a meeting of ministers from over 140 governments.

Conservation of Natural Resources↗

Nosocomial transmission and infection control aspects of parasitic and ectoparasitic diseases. Part III. Ectoparasites/summary and conclusions.

As a rule, both the standard of hygiene and sanitation prevalent in hospitals in the United States and the rarity of parasitic diseases compared to viral, bacterial, and fungal infections, reduce the hazard of nosocomial acquisition of parasites to relatively trivial levels. However, abetted by the resultant low index of suspicion on the part of clinical staff, certain parasitic microorganisms may at times cause significant morbidity and even mortality in both normal and immunocompromised patients, as summarized in this review. Also, the nosocomial acquisition of parasites may be somewhat underappreciated because the incubation period for clinical illness may be days to weeks and thus a hospital-acquired infection may not be recognized as such, particularly if the parasite is endemic locally. Parasitic diseases have been a much more significant problem in certain special facilities, such as custodial institutions for the mentally ill or retarded, where crowding, poor environmental sanitation, and low levels of personal hygiene have in the past allowed the rapid dissemination and endemic occurrence of a large variety of parasitic infections. It is likely that nosocomial transmission of parasites may be an even greater problem in some hospitals in the tropics, where strict hygienic standards are costly or otherwise more difficult to maintain, and where often an increased proportion of the patient population harbors one or more parasites. However, the exact magnitude of the problem in tropical hospitals is also more difficult to determine because nosocomial acquisition of a parasitic infection may not be distinguished easily versus exogenous infection or reactivation of latent infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

School and anaemia prevention: current reality and opportunities--a Tanzanian case study.

Iron deficiency anaemia is highly endemic in rural areas of Tanzania and in many developing countries. Its prevention among school children requires greater dissemination of knowledge of anaemia among children, teachers, parents and the general community. Associated improvements in the hygienic status of domestic and school environments are also often required. One-hundred-and-thirty-one anaemic children, 90 parents and 76 teachers were interviewed to ascertain their understanding of anaemia. Most children and parents had little knowledge of the symptoms, causes and prevention of anaemia. In addition to their iron-deficient diets, more than half of the children went to school without something to eat at breakfast and during school hours. However, parents and teachers were willing to work together to provide meals for the children. Poor sanitation in the children's homes and in schools was a little recognized factor which could pose a serious risk of anaemia. In addition, inadequate sanitation facilities and poor quality of physical environment prevailed both in the children's homes and in schools. The findings suggest the need for the establishment of a health-promoting schools network to provide a comprehensive framework for health promotion in schools as well as in homes in Tanzania and in other developing countries. Schools can be an ideal setting to positively influence a community's health status. Partnerships among teachers, parents and the wider community are required to identify, prioritize and ameliorate health problems.

Adult↗

A cost-benefit analysis of programmatic use of CVD 103-HgR live oral cholera vaccine in a high-risk population.

BACKGROUND: Cholera spread to Latin America in 1991; subsequently, cholera vaccination was considered as an interim intervention until long-term solutions involving improved water supplies and sanitation could be introduced. Three successive summer cholera outbreaks in northern Argentina and the licensing of the new single-dose oral cholera vaccine, CVD 103-HgR, raised questions of the cost and benefit of using this new vaccine. METHODS: This study explored the potential benefits to the Argentine Ministry of Health of treatment costs averted, versus the costs of vaccination with CVD 103-HgR in the relatively confined population of northern Argentina affected by the cholera outbreaks. Water supplies and sanitation in this area are poor but a credible infrastructure for vaccine delivery exists. RESULTS: In our cost-benefit model of a 3-year period (1992-1994) with an annual incidence of 2.5 case-patients per 1000 population and assumptions of vaccine efficacy of 75% and coverage of 75%, vaccination of targeted high risk groups would prevent 1265 cases. CONCLUSION: Assuming a cost of US$602 per treated case and of US$1.50 per dose of vaccine, the total discounted savings from use of vaccine in the targeted groups would be US$132,100. The projected savings would be altered less by vaccine coverage (range 75-90%) or efficacy (60-85%) changes than by disease incidence changes. Our analysis underestimated the true costs of cholera in Argentina because we included only medical expenditures; Indirect losses to trade and tourism had the greatest economic impact. However, vaccination with CVD 103-HgR was still cost-beneficial in the base case.

Adolescent↗

Epidemiology of Escherichia coli in the United States.

Current evidence suggests that diarrheagenic E. coli are not important causes of disease in the sanitized urban centers of the United States at this time. However, enterotoxigenic E. coli are a leading cause of diarrhea among travelers who visit developing countries. The failure of diarrheagenic E. coli pathogens to gain a foothold in this country, despite problems with enteropathogenic E. coli in nurseries during the 1940s and 1950s and the more recent multiple introductions of enterotoxigenic E. coli by travelers returning from developing areas of the world, demonstrates the epidemiologic impotence of diarrheagenic E. coli in the relatively sanitized environment of the United States. Nondiarrheagenic E. coli seem to be major pathogens in community-acquired and nosocomial infections in extraintestinal sites.

Developing Countries↗

History and epidemiology of hepatitis A virus.

Hepatitis A was clearly recognized as an entity separate from other types of hepatitis during World War II, but only later did studies provide convincing evidence of the prevalence and transmission of hepatitis A virus (HAV). Disease incidence varies over time and geography, with wide differences from country to country and even within cities. Noted recently is a shift in prevalence in cases from childhood to adulthood. Incidence figures are unreliable. Epidemiology of the disease is best defined by measurement of anti-HAV antibodies. HAV is a very stable virus, frequently found in urban sewage. Infections occur early in life when sanitation is poor and living conditions crowded, but improvements in sanitation and hygiene have delayed infection, resulting in increasing numbers of adults susceptible to HAV. Transmission of HAV by blood is rare. High-risk persons include injection drug users, institutionalized persons and their caretakers, and those who travel from low-prevalence to high-prevalence countries.

Hepatitis A↗

Evaluation of different linker regions for multimerization and coupling chemistry for immobilization of a proteinaceous affinity ligand.

Alkaline conditions are generally preferred for sanitization of chromatography media by cleaning-in-place (CIP) protocols in industrial biopharmaceutical processes. The use of such rigorous conditions places stringent demands on the stability of ligands intended for use in affinity chromatography. Here, we describe efforts to meet these requirements for a divalent proteinaceous human serum albumin (HSA) binding ligand, denoted ABD*dimer. The ABD*dimer ligand was constructed by genetic head-to-tail linkage of two copies of the ABD* moiety, which is a monovalent and alkali-stabilized variant of one of the serum albumin-binding motifs of streptococcal protein G. Dimerization was performed to investigate whether a higher HSA-binding capacity could be obtained by ligand multimerization. We also investigated the influence on alkaline stability and HSA-binding capacity of three variants (VDANS, VDADS and GGGSG) of the inter-domain linker. Biosensor binding studies showed that divalent ligands coupled using non-directed chemistry demonstrate an increased molar HSA-binding capacity compared with monovalent ligands. In contrast, equal molar binding capacities were observed for both types of ligands when using directed ligand coupling chemistry involving the introduction and recruitment of a unique C-terminal cysteine residue. Significantly higher molar binding capacities were also detected when using the directed coupling chemistry. These results were confirmed in affinity chromatography binding capacity experiments, using resins containing thiol-coupled ligands. Interestingly, column sanitization studies involving exposure to 0.1 M NaOH solution (pH 13) showed that of all the tested constructs, including the monovalent ligand, the divalent ligand construct containing the VDADS linker sequence was the most stable, retaining 95% of its binding capacity after 7 h of alkaline treatment.

Bacterial Proteins↗

Does the failure to acquire helminthic parasites predispose to Crohn's disease?

Two polarized patterns (Th1 and Th2) of cytokines regulate inflammatory responses. Each cytokine pattern inhibits production of the opposing pattern. Lymphocytes from inflamed intestine due to Crohn's disease secrete a Th1 pattern of cytokines. Crohn's disease is most prevalent in highly industrialized countries with temperate climates. It occurs rarely in tropical third world countries with poor sanitation. We propose that exposure to an environmental agent predisposes individuals to Crohn's disease. Parasitic worms (helminths) are common in tropical climates and in populations subject to crowding and poor sanitation. Children are most subject to helminthic colonization. Many helminths live within or migrate through the human gut where they interact with the mucosal immune system. The host mounts a mucosal response that includes Th2 cytokine production limiting helminthic colonization. Helminths and their eggs probably are the most potent stimulators of mucosal Th2 responses. The Th2 response provoked by parasitic worms can modulate immune reactions to unrelated parasitic, bacterial, and viral infections. Many people in developed countries now live in increasingly hygienic environments, avoiding exposure to helminths. Perhaps failure to acquire these parasites and experience mucosal Th2 conditioning predisposes to Crohn's disease, which is an overly active Th1 inflammation.

Animals↗

Appropriate technologies for environmental hygiene.

Appropriate technologies for environmental hygiene usually centre on the delivery of adequate and accessible water supply, and proper treatment and disposal of excreta and refuse. In the face of the International Drinking Water and Sanitation Decade of 1981-90, several research efforts are under way in the developing countries to develop technologies and approaches for improving environmental hygiene in both rural areas and urban squatter settlements. These are discussed and include the technical development and field testing of infiltration galleries, low-cost slow and fast filtration processes for water treatment, handpumps, on-site excreta disposal using aqua-privy and compost toilets, and excreta treatment and refuse through composting with refuse, biogas generation, fish culture and use of excreta as crop fertilizer. The relevant technology 'hardware' is but one of several components necessary for effective delivery of services. The dearth of qualified manpower at all levels is described as being the major constraint to the Water and Sanitation Decade.

Developing Countries↗

Demographics, Overlap, and Latency of Severe Cutaneous Adverse Reactions in an FDA Database.

IMPORTANCE: Severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS-TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP), and generalized bullous fixed drug eruption (GBFDE), are rare but life-threatening drug hypersensitivity syndromes. Due to their low incidence and diagnostic complexity, large-scale characterization of SCAR is challenging. OBJECTIVE: To characterize the demographics, causative agents, trends, latency, and phenotypic overlap of SCAR using a large-scale, sanitized pharmacovigilance dataset from FAERS (FDA Adverse Event Reporting System). DESIGN: Cross-sectional study of spontaneous adverse event reports. Cases were drawn from the U.S. Food and Drug Administration Adverse Event Reporting System (FDA FAERS) from January 2004 to December 2023 and subjected to sanitization and deduplication. Disproportionality analysis was used to characterize causative agents. Machine learning (random forest classifiers) was used to analyze predictors of drug latency and mortality. SETTING: Global pharmacovigilance reports submitted to FAERS. PARTICIPANTS: A total of 56,683 deduplicated SCAR reports were identified, representing 0.33% of reports during the study period. EXPOSURES: Suspected causative drugs, including both small molecules and biologics. MAIN OUTCOMES AND MEASURES: Main outcomes included the frequency and distribution of SCAR syndromes, reporting trends over time, latency from drug start to reaction onset, drug-specific disproportionality (PRR, ROR, IC), and co-reporting between SCAR types and related conditions. RESULTS: A total of 56,683 unique SCAR reports were identified, including SJS-TEN (28,871), DRESS (22,444), AGEP (6,183), and GBFDE (150). We identified 237 drugs with significant disproportionality for SCAR overall. Co-reporting between SCARs was significantly enriched (p < 1e-200), suggesting overlapping phenotypes. Latency varied by drug and syndrome (median: GBFDE 3 days, AGEP 4 days, SJS-TEN 12 days, DRESS 20 days). CONCLUSIONS AND RELEVANCE: SCAR syndromes display distinct but overlapping phenotypes, with variable latency and diverse causative agents. These findings, based on the largest SCAR dataset to date, highlight the need for improved classification frameworks and molecular validation. Large-scale pharmacovigilance, integrated with genomic and histopathologic data, will be critical to improving diagnosis, mechanistic understanding, and clinical management of SCAR.

Acute Generalized Exanthematous Pustulosis↗

Environmental health conditions in remote and rural aboriginal communities in western Australia.

During 1994-1995 environmental health conditions of about 13,760 persons in 155 remote and rural Aboriginal communities in 20 local shires in Western Australia (WA) were surveyed. A semiquantitative questionnaire sought data about the communities and their services, including water supplies, power, sanitation and disposal of solid and liquid waste; a separate section dealt with conditions of individual dwellings. Data were recorded by experienced local workers. Thirty-five communities considered to have the worst conditions were evaluated on-site by a team of senior personnel in mid-1995. Environmental health problems were prevalent and often serious: over one-third of the communities had water supply or sanitation problems and 70 per cent had housing problems, with overcrowding and substandard housing being commonplace. Thirty-six per cent had difficulties with waste water disposal, 37 per cent had no rubbish disposal, and in others, the methods of disposal were often inadequate; pests were problems in 44 per cent of communities and the hygiene and maintenance of communal toilets was unacceptable in 25 per cent. Seventy-two per cent had no on-site environmental health worker and 44 per cent had no on-site or visiting medical, nursing or health worker personnel. An action plan was developed and the highest-priority communities were targeted in a program of major works (for example, housing, drainage and sewerage) and minor works, which have been commenced. The remote-area environmental health workers' program is being expanded. Increased intersectoral collaboration and enhanced community involvement in decision making have occurred as a result of this work.

Child Welfare↗

The agony and the ecstasy.

The authors, who are from the Vessel Sanitation Program of the Centers for Disease Control and Prevention (CDC), summarize the recent outbreaks of acute gastroenteritis (AGE), which occurred on five different cruise ships. Attack rates among passengers ranged from 4% to 13% and among crew members from 0.2% to 3.3%. Subsequent epidemiological investigations by the CDC suggested that the incidence was higher, approaching 19-41% of passengers. Overall there were 21 outbreaks of AGE on 17 cruise ships, of which nine were documented to be due to norovirus, three due to bacterial agents, and nine of unknown cause. In general, subsequent outbreaks on each cruise ship were of the identical strain of norovirus by reverse transcriptase polymerase reaction, which suggests an embedded source. The authors conclude that in addition to emphasizing basic food and water sanitation measures, control efforts should include thorough and prompt disinfection of ships during cruises and isolation of ill crew-members and passengers for 72 hours.

Centers for Disease Control and Prevention, U.S.↗

Rapid health assessment in Aceh Jaya District, Indonesia, following the December 26 tsunami.

OBJECTIVES: To rapidly determine the public health impact of the Asian tsunami on the population of three communities in Aceh Jaya District, Indonesia, and to prioritize health interventions. METHODS: Rapid health assessment, utilizing direct observations, interviews with key informants, a single focus group discussion, town mapping, a review of medical records and a systematic random sample of the entire town of Calang, capital of Aceh Jaya District, Indonesia. RESULTS: Almost 100% of dwellings were destroyed in all three communities. For the town of Calang: only 18.2% of the pre-tsunami population remained 2 weeks following the disaster, with an estimated 70% of the population having died at the time of impact; government estimates of the remaining population were inflated by approximately 250%; mortality rates were not elevated post-tsunami; 100% of the population lacked access to sanitation and clean water; 85% of children under 5 years reported diarrhoea over the preceding 2 week period; 95% of individuals with a medical complaint reported satisfactory access to clinical care; acute malnutrition was not a significant problem; and over one-fifth of households were hosting an orphan. For the villages of Rigah and Sayeung: approximately 46.2 and 86.0% of the population survived the tsunami impact, respectively; mortality rates were not elevated post tsunami; 100% of the population lacked access to sanitation and clean water; diarrhoea was the main cause of morbidity; primary care services were available only in Rigah; and only Rigah had received external assistance. CONCLUSIONS: Almost two-thirds of the population of the three communities died as a result of the tsunami's impact. Although mortality rates were not elevated post tsunami, significant threats to public health persisted, especially water-borne diseases. Priority activities included emergent environmental health interventions, mobile clinics to the two villages and a more detailed assessment of the needs of orphans. Data were shared with agencies better placed to address needs in the areas of shelter and food aid.

Adolescent↗

Eradication of Salmonella and Arizona species from turtle hatchlings produced from eggs treated on commercial turtle farms.

On commercial turtle farms more than 40% of the hatchlings excrete detectable levels of Salmonella and Arizona spp. when hatched from nonsanitized eggs incubated in sawdust or dirt-filled chambers. Over a 3-year period on 10 farms, more than 10(6) turtle eggs were treated in an attempt to hatch Salmonella-free turtles. Eggs were sanitized in disinfectant, treated by temperature- or pressure-differential dip methods in solutions containing 500 micrograms or more of gentamicin sulfate per ml, and hatched in sanitized plastic chambers free of bedding material. The Salmonella and Arizona spp. infection levels for turtles produced from treated eggs were 0 and 1.12% for years 1 and 2, respectively, whereas infection levels for hatchlings produced from nontreated eggs during these periods were 47 and 44%, respectively. During year 3, dip solutions were filtered daily, treated at 100 degrees C for 15 min on a weekly basis to free the solution of microbial contaminants and egg protein, charged with gentamicin after 10,000 to 20,000 eggs had been treated to maintain antimicrobial activity at 500 micrograms/ml or more, and maintained at pH 6.0 to preserve optimal antimicrobial activity. The implementation of these measures in year 3 resulted in an infection level of 0.15% when the tissues of 3 of 1,959 hatchlings tested were positive for Salmonella and Arizona spp., whereas the tissues of 66 (49.0%) of 135 hatchlings produced from nontreated eggs were positive.

Animals↗

Curvularia haloperoxidase: antimicrobial activity and potential application as a surface disinfectant.

A presumed antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of evaluating its potential as a sanitizing agent. In the presence of hydrogen peroxide, Curvularia haloperoxidase facilitates the oxidation of halides, such as chloride, bromide, and iodide, to antimicrobial compounds. The Curvularia haloperoxidase system caused several-log-unit reductions in counts of bacteria (Pseudomonas spp., Escherichia coli, Serratia marcescens, Aeromonas salmonicida, Shewanella putrefaciens, Staphylococcus epidermidis, and Listeria monocytogenes), yeasts (Candida sp. and Rhodotorula sp.), and filamentous fungi (Aspergillus niger, Aspergillus tubigensis, Aspergillus versicolor, Fusarium oxysporum, Penicillium chrysogenum, and Penicillium paxilli) cultured in suspension. Also, bacteria adhering to the surfaces of contact lenses were killed. The numbers of S. marcescens and S. epidermidis cells adhering to contact lenses were reduced from 4.0 and 4.9 log CFU to 1.2 and 2.7 log CFU, respectively, after treatment with the Curvularia haloperoxidase system. The killing effect of the Curvularia haloperoxidase system was rapid, and 10(6) CFU of E. coli cells/ml were eliminated within 10 min of treatment. Furthermore, the antimicrobial effect was short lived, causing no antibacterial effect against E. coli 10 min after the system was mixed. Bovine serum albumin (1%) and alginate (1%) inhibited the antimicrobial activity of the Curvularia haloperoxidase system, whereas glucose and Tween 20 did not affect its activity. In conclusion, the Curvularia haloperoxidase system is an effective sanitizing system and has the potential for a vast range of applications, for instance, for disinfection of contact lenses or medical devices.

Bacteria↗

Inactivation of Bacillus endospores in envelopes by electron beam irradiation.

The anthrax incidents in the United States in the fall of 2001 led to the use of electron beam (EB) processing to sanitize the mail for the U.S. Postal Service. This method of sanitization has prompted the need to further investigate the effect of EB irradiation on the destruction of Bacillus endospores. In this study, endospores of an anthrax surrogate, B. atrophaeus, were destroyed to demonstrate the efficacy of EB treatment of such biohazard spores. EB exposures were performed to determine (i) the inactivation of varying B. atrophaeus spore concentrations, (ii) a D10 value (dose required to reduce a population by 1 log10) for the B. atrophaeus spores, (iii) the effects of spore survival at the bottom of a standardized paper envelope stack, and (iv) the maximum temperature received by spores. A maximum temperature of 49.2 degrees C was reached at a lethal dose of approximately 40 kGy, which is a significantly lower temperature than that needed to kill spores by thermal effects alone. A D10 value of 1.53 kGy was determined for the species. A surface EB dose between 25 and 32 kGy produced the appropriate killing dose of EB between 11 and 16 kGy required to inactivate 8 log10 spores, when spore samples were placed at the bottom of a 5.5-cm stack of envelopes.

Anthrax↗

Antimicrobial action of carvacrol at different stages of dual-species biofilm development by Staphylococcus aureus and Salmonella enterica serovar Typhimurium.

The effects of carvacrol, a natural biocide, on dual-species biofilms formed by Staphylococcus aureus and Salmonella enterica serovar Typhimurium were investigated with a constant-depth film fermentor. Biofilm development reached a quasi-steady state in 12 days at 25 degrees C with S. aureus predominance ( approximately 99%). Cryosectional analysis detected viable S. aureus and S. enterica serovar Typhimurium at depths of 320 and 180 mum from the film surface, respectively. Carvacrol pulses (1.0 mmol/h) inhibited S. aureus by 2.5 log CFU/biofilm during the early stages of film formation, ultimately causing a significant reduction (P < 0.001) of the staphylococcal population at quasi-steady state. Initial carvacrol pulsing elicited a 3 log CFU/biofilm reduction in viable S. enterica serovar Typhimurium, and additional periodic carvacrol pulses instigated significant inhibition of salmonellae (1 to 2 log CFU/biofilm) during biofilm development. Carvacrol pulsing reduced protein levels fivefold (P < 0.001) during initial biofilm development. Comparative studies with a peroxide-based commercial sanitizer (Spor-Klenz RTU) revealed that this commercial sanitizer was more biocidal than carvacrol during early biofilm development. When the biofilm reached quasi-steady state, however, periodic pulses with 1 mmol of carvacrol per h (P = 0.021) elicited a significantly higher inhibition than Spor-Klenz RTU (P = 0.772). Dual-species microcolonies formed under the influence of continuously fed low carvacrol concentrations (1.0 mmol/h) but failed to develop into a mature quasi-steady-state biofilm and did not reach any stage of film formation in the presence of high concentrations (5.0 mmol/h). These data show that carvacrol is an effective natural intervention to control dual-species biofilm formation.

Biofilms↗