Sublethal Sodium Hypochlorite Exposure: Impact on Resistance-Nodulation-Cell Division Efflux Pump Overexpression and Cross-Resistance to Imipenem.

Sodium hypochlorite (NaOCl) is widely used in public healthcare facilities; this exposure can result in the development of bacterial tolerance to disinfectants, which has known links to antibiotic cross-resistance. However, the mechanism through which cross-resistance to antibiotics and disinfectants develops remains ambiguous. Therefore, this study aimed to examine the phenotypic and transcriptomic changes caused by disinfectant exposure in Gram-negative bacteria and determine the cause of cross-resistance to antibiotics. The results demonstrated that the misuse of disinfectants plays an important role in the emergence of disinfectant resistance and in the increase in antibiotic resistance. Antibiotic resistance may occur from the exposure of Gram-negative bacteria to subminimal inhibitory concentrations (MICs) of NaOCl. Ten passages of Gram-negative bacteria in increasingly higher subMICs of the NaOCl disinfectant were sufficient to increase the MIC to >2500 µg/mL NaOCl, particularly in K. pneumoniae and P. aeruginosa. To determine the development of cross-resistance to antibiotics due to NaOCl exposure, the MICs for each antibiotic before and after the exposure of each strain to sublethal concentrations of NaOCl were compared. After overnight incubation with a sublethal concentration of NaOCl, a statistically significant increase in MIC was only observed for imipenem (p < 0.01). An investigation of the mechanism of cross-resistance by means of transcriptome analysis revealed that 1250 µg/mL of NaOCl-adapted K. pneumoniae and P. aeruginosa strains increased resistance to imipenem due to the increased expression of resistance-nodulation-cell division (RND) efflux pumps, such as AcrAB-TolC and MexAB/XY-OprM. Therefore, we suggest that exposure to NaOCl can influence the expression of RND efflux pump genes, contributing to imipenem cross-resistance.

Complex Infection-Control Measures with Disinfectant Switch Help the Successful Early Control of Carbapenem-Resistant Acinetobacter baumannii Outbreak in Intensive Care Unit.

A carbapenem-resistant Acinetobacter baumannii (CRAB) outbreak in an intensive care unit (ICU) was contained by an improved infection-control measure that included a disinfectant policy. In our retrospective cohort study, we describe the epidemiological investigations and infection-control measures during this outbreak. Descriptive analysis was used to summarize patient demographics, neurological diseases, surgical treatment, underlying diseases, infection, and outcomes. In December 2023, two CARB-positive patients were observed in the ICU, and four more patients became CRAB-positive in January. During this outbreak, there was an overlap of hospitalization periods among the CRAB-positive patients, and CRAB was isolated from the environment; the isolated CRAB strain was identical. Infection-control measures, including hand hygiene, contact precautions and isolation, surveillance, decolonization, environmental cleaning, and disinfection, were reviewed and modified. The aim of this study was to examine the molecular background of the effectiveness of the disinfectant shift used during successful outbreak control. Experiments were carried out to study the phenotypic sensitivity and genetic background of different disinfectant agents. A thorough analysis of the detected CRAB strain included whole-genome sequencing (WGS), investigation of the qacE and qacEΔ1 genes' relative expression by qPCR after exposure to different disinfectant solutions, as well as an analysis of biofilm formation. WGS analysis of the CRAB strain identified that an ST2 high-risk clone was responsible for the outbreak, which produced OXA-83 and ADC-30 beta-lactamases; in addition, qacE and qacEΔ1 genes were also detected, which confer resistance to disinfectants containing quaternary ammonium compounds (QACs). A qPCR analysis demonstrated that after exposure to different disinfectants, the gene expression levels of qacE and qacEΔ1 increased and correlated with concentrations of QACs of disinfectants. During the outbreak, the standard-of-care QAC-based disinfectant was changed to a mainly alcohol-based agent in the ICU, which contributed to the successful control of this outbreak, and no additional patients were identified with CRAB. We conclude that continuous surveillance and hand hygiene training combined with fast identification and reaction to new cases, as well as an in-depth analysis of multidrug-resistant outbreak strains and investigation of their disinfectant tolerance/resistance during an outbreak, are essential to effectively control the spread of nosocomial pathogens. The smart policy of disinfectant agent selection played a crucial role in controlling the outbreak and ensuring patient safety in the ICU.

Adaptations to cationic biocide exposure differentially influence virulence factors and pathogenicity in Pseudomonas aeruginosa.

Cationic biocides (CBs), which include quaternary ammonium compounds (QACs), are employed to mitigate the spread of infectious bacteria, but resistance to such surface disinfectants is rising. CB exposure can have profound phenotypic implications that extend beyond allowing microorganisms to persist on surfaces. Pseudomonas aeruginosa is a deadly bacterial pathogen that is intrinsically tolerant to a wide variety of antimicrobials and is commonly spread in healthcare settings. In this study, we pursued resistance selection assays to the QAC benzalkonium chloride and quaternary phosphonium compound P6P-10,10 to assess the phenotypic effects of CB exposure in P. aeruginosa PAO1 and four genetically diverse, drug-resistant clinical isolates. In particular, we sought to examine how CB exposure affects defensive strategies and the virulence-associated "offensive" strategies in P. aeruginosa. We demonstrated that development of resistance to BAC is associated with increased production of virulence-associated pigments and alginate as well as pellicle formation. In an in vivo infection model, CB-resistant PAO1 exhibited a decreased level of virulence compared to wild type, potentially due to an observed fitness cost in these strains. Taken together, these results illustrate the significant consequence CB resistance exerts on the virulence-associated phenotypes of P. aeruginosa.

Lysine and valine weaken antibiotic resistance in Salmonella Typhimurium induced by disinfectant stress.

Disinfectants are widely used in food production and environmental sanitation to prevent illness, but bacteria resistance to these disinfectants and co-resistance to antibiotics pose a threat to public health. This study investigated the impact of commonly used disinfectants on the resistance of Salmonella Typhimurium (ST) to disinfectants and antibiotics, and explored the metabolic mechanisms underlying the resistance changes. The results showed that subinhibitory concentrations of disinfectants had a minor impact on the resistance of ST to four disinfectants. However, chlorine-containing disinfectants stress enhanced bacteria resistance to ampicillin, while quaternary ammonium compounds stress increased resistance to tetracycline and gentamicin. Untargeted metabolomics analysis revealed significant changes in glutathione metabolism and lysine and valine degradation pathways after disinfectant exposure. Specifically, ST activated lysine decarboxylation, leading to a significant decrease in lysine levels after benzalkonium chloride exposure, while valine and leucine degradation pathways were activated by sodium hypochlorite stress. The addition of downregulated L-lysine and L-valine increased the sensitivity of ST to antibiotics, providing further evidence for the findings of metabolomics. This study provides guidance for the proper use of disinfectants in food processing and establishes a strategy based on metabolomics to control antibiotic-resistant bacteria.

EVALUATION OF THE CYSTICIDAL ACTIVITY OF CHLOROCRESOL AGAINST ACANTHAMOEBA POLYPHAGA.

Chlorocresol has antibacterial and antifungal properties, yet its effectiveness in eradicating Acanthamoeba spp. remains unexplored. Acanthamoeba species trophozoites are usually sensitive to biocides, whereas cysts tend to be more resistant. This study aimed to evaluate the cysticidal activity of chlorocresol against Acanthamoeba polyphaga. Chlorocresol concentrations of 0.02, 0.04, and 0.08% were prepared and A. polyphaga cysts were incubated at room temperature (28-37 C) for 1, 24, 48, and 72 hr at each concentration. Cyst viability was evaluated using trypan blue staining and the percentage of nonviable cysts was calculated. For qualification assays, treated cysts were cultured on nonnutrient agar medium coated with Escherichia coli, incubated at 30 C, observed under a stereomicroscope for 30 days, and inoculated into peptone-yeast extract-glucose medium at 30 C for 72 hr. The results revealed that the A. polyphaga cysts were susceptible to 0.02, 0.04, and 0.08% chlorocresol. Chlorocresol made a significant difference in viability (P < 0.001) compared with the nontreated control for the same incubation time. This is the first study to examine the efficacy of chlorocresol against A. polyphaga cysts and it was highly effective. Chlorocresol could thus serve as an alternative chemical disinfectant for the eradication of A. polyphaga cysts as well as a prophylactic against transmission of other pathogenic microorganisms for which Acanthamoeba species can act as a carrier.

Reactive species of plasma-activated water for murine norovirus 1 inactivation.

Human norovirus (HuNoV), the leading cause of foodborne acute gastroenteritis, poses a serious threat to public health. Traditional disinfection methods lead to destructions of food properties and functions, and/or environmental contaminations. Green and efficient approaches are urgently needed to disinfect HuNoV. Plasma-activated water (PAW) containing amounts of reactive species is an emerging nonthermal and eco-friendly disinfectant towards the pathogenic microorganisms. However, the disinfection efficacy and mechanism of PAW on HuNoV has not yet been studied. Murine norovirus 1 (MNV-1) is one of the most commonly used HuNoV surrogates to evaluate the efficacy of disinfectants. In the current study, the inactivation efficacy of MNV-1 by PAW was investigated. The results demonstrated that PAW significantly inactivated MNV-1, reducing the viral titer from approximately 6 log10 TCID50/mL to non-detectable level. The decreased pH, increased oxidation-reduction potential (ORP) and conductivity of PAW were observed compared with that of deionized water. Compositional analysis revealed that hydrogen peroxide (H2O2), nitrate (NO3-) and hydroxyl radical (OH) were the functional reactive species in MNV-1 inactivation. L-histidine could scavenge most of the inactivation effect in a concentration-dependent manner. Moreover, PAW could induce damage to viral proteins. Part of MNV-1 particles was destroyed, while others were structurally intact without infectiousness. After 45 days of storage at 4 °C, PAW generated with 80 % O2 and 100 % O2 could still reduce over 4 log10 TCID50/mL of the viral titer. In addition, PAW prepared using hard water induced approximately 6 log10 TCID50/mL reduction of MNV-1. PAW treatment of MNV-1-inoculated blueberries reduced the viral titer from 3.79 log10 TCID50/mL to non-detectable level. Together, findings of the current study uncovered the crucial reactive species in PAW inactivate MNV-1 and provided a potential disinfection strategy to combat HuNoV in foods, water, and environment.

Reuterin Enhances the Efficacy of Peracetic Acid Against Multi-species Dairy Biofilm.

Biofilms may contain pathogenic and spoilage bacteria and can become a recurring problem in the dairy sector, with a negative impact on product quality and consumer health. Peracetic acid (PAA) is one of the disinfectants most frequently used to control biofilm formation and persistence. Though effective, it cannot be used at high concentrations due to its corrosive effect on certain materials and because of toxicity concerns. The aim of this study was to test the possibility of PAA remaining bactericidal at lower concentrations by using it in conjunction with reuterin (3-hydroxypropionaldehyde). We evaluated the efficacy of PAA in pure form or as BioDestroy®, a PAA-based commercial disinfectant, on three-species biofilms formed by dairy-derived bacteria, namely Pseudomonas azotoformans PFlA1, Serratia liquefaciens Sl-LJJ01, and Bacillus licheniformis Bl-LJJ01. Minimum inhibitory concentrations of the three agents were determined for each bacterial species and the fractional inhibitory concentrations were then calculated using the checkerboard assay. The minimal biofilm eradication concentration (MBEC) of each antibacterial combination was then calculated against mixed-species biofilm. PAA, BioDestroy®, and reuterin showed antibiofilm activity against all bacteria within the mixed biofilm at respectively 760 ppm, 450 ppm, and 95.6 mM. The MBEC was lowered significantly to 456 ppm, 337.5 ppm, and 71.7 mM, when exposed to reuterin for 16 h followed by contact with disinfectant. Combining reuterin with chemical disinfection shows promise in controlling biofilm on food contact surfaces, especially for harsh or extended treatments. Furthermore, systems with reuterin encapsulation and nanotechnologies could be developed for sustainable antimicrobial efficacy without manufacturing disruptions.

Effects of antibiotic and disinfectant exposure on the mouse gut microbiome and immune function.

This study explores the effects of disinfectant and antibiotic exposure on gut health, focusing on gut microbiota balance and gut immune function. Our analysis indicates that disinfectants increase the proportion of Gram-positive bacteria, particularly increasing Staphylococcus levels, while antibiotics increase the proportion of Gram-negative bacteria, especially Bacteroides levels. These changes disrupt microbial harmony and affect the gut microbiome's functional capacity. Additionally, our research reveals that both disinfectants and antibiotics reduce colon length and cause mucosal damage. A significant finding is the downregulation of NLRC4, a key immune system regulator in the gut, accompanied by changes in immune factor expression. This interaction between chemical exposure and immune system dysfunction increases susceptibility to inflammatory bowel disease and other gut conditions. Given the importance of disinfectants in disease prevention, this study advocates for a balanced approach to their use, aiming to protect public health while minimizing adverse effects on the gut microbiome and immune function. IMPORTANCE: Disinfectants are extensively employed across various sectors, such as the food sector. Disinfectants are widely used in various sectors, including the food processing industry, animal husbandry, households, and pharmaceuticals. Their extensive application risks environmental contamination, impacting water and soil quality. However, the effect of disinfectant exposure on the gut microbiome and the immune function of animals remains a significant, unresolved issue with profound public health implications. This highlights the need for increased scrutiny and more regulated use of disinfectants to mitigate unintended consequences on gut health and maintain immune system integrity.

Hypervirulent Klebsiella pneumoniae with a hypermucoviscosity phenotype challenges strategies of water disinfection for its capsular polysaccharides.

Due to the strong pathogenicity of hypervirulent Klebsiella pneumoniae (hvKP), its performance against disinfectants in water should be understood to protect public health and ecological environment. Unfortunately, the disinfectant tolerance of hvKP with a hypermucoviscosity (HMV) phenotype is a critical underexplored area. Here, the tolerance of K. pneumoniae isolates to common disinfectants was evaluated, and its underlying mechanisms were clarified. Results showed that hvKP strains with HMV exhibited remarkable tolerance to triclosan (TCS), sodium hypochlorite (NaClO), and benzalkonium bromide (BB), surpassing that of low-virulent K. pneumoniae (lvKP) and Escherichia coli, which is the microbial indicator of drinking water quality. Ct value of NaClO reached 4.41 mg/L·min to kill 4-log hvKP, while the values were 2.52 and 2.28 mg/L·min to achieve 4-log killing of lvKP and E. coli, respectively. The curing of the virulence plasmid from hvKP strain K2044 revealed that capsular polysaccharide (CPS) synthesis, driven by the virulence plasmids, helped mitigate cell membrane injury and bacterial inactivation under NaClO stress; consequently, it provided a protective advantage to hvKP. Enhancing the antioxidative stress system to reduce ROS production and mitigate oxidative stress caused by NaClO further improved the disinfectant resistance of hvKP strains with HMV. This study emphasized that hvKP strains with HMV posed a considerable challenge to disinfection procedure of water treatment. It also revealed that an improved dosage of NaClO ensures bacteria killing, indicating the optimization of the design of water treatment processes involving disinfection strategies and technical parameters should be considered.

A systematic review and BMD modeling approach to develop an AOP for humidifier disinfectant-induced pulmonary fibrosis and cell death.

Dosimetry modeling and point of departure (POD) estimation using in vitro data are essential for mechanism-based hazard identification and risk assessment. This study aimed to develop a putative adverse outcome pathway (AOP) for humidifier disinfectant (HD) substances used in South Korea through a systematic review and benchmark dose (BMD) modeling. We collected in vitro toxicological studies on HD substances, including polyhexamethylene guanidine hydrochloride (PHMG-HCl), PHMG phosphate (PHMG-p), a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (CMIT/MIT), CMIT, and MIT from scientific databases. A total of 193 sets of dose-response data were extracted from 34 articles reporting in vitro experimental results of HD toxicity. The risk of bias (RoB) in each study was assessed following the office of health assessment and translation (OHAT) guideline. The BMD of each HD substance at different toxicity endpoints was estimated using the US Environmental Protection Agency (EPA) BMD software (BMDS). Interspecies- or interorgan differences or most critical effects in the toxicity of the HD substances were analyzed using a 95% lower confidence limit of the BMD (BMDL). We found a critical molecular event and cells susceptible to each HD substance and constructed an AOP of PHMG-p- or CMIT/MIT-induced damage. Notably, PHMG-p induced ATP depletion at the lowest in vitro concentration, endoplasmic reticulum (ER) stress, epithelial-to-mesenchymal transition (EMT), inflammation, leading to fibrosis. CMIT/MIT enhanced mitochondrial reactive oxygen species (ROS) production, oxidative stress, mitochondrial dysfunction, resulting in cell death. Our approach will increase the current understanding of the effects of HD substances on human health and contribute to evidence-based risk assessment of these compounds.

Effectiveness of Ultraviolet Radiation and Disinfectant Wipes in Reducing the Microbial Contamination of Mobile Phones in a Tertiary Care Hospital.

Background As mobile phones act as a potential source of microbial contamination, particularly in a hospital environment, the effectiveness of two most debated interventions namely ultraviolet radiation and disinfectant wipes in reducing the microbial contamination of mobile phones is compared. Objective To screen the mobile phones of healthcare personnel for the presence of microorganisms and to compare the effectiveness of ultraviolet radiation and disinfectant wipes in reducing microbial contamination. Methods and materials Pre-intervention and post-intervention swabs were collected before and after the use of each intervention respectively using 56 samples and cultured for growth in nutrient agar. Agar plates are subjected to quantitative analysis using bacterial colony count to reflect the efficacy of the specific intervention used. The data collected was entered in Microsoft Excel (Microsoft® Corp., Redmond, WA, USA) and analysis was done using standard statistical packages. Results While comparing the pre-intervention bacterial load with the post-intervention load, post-intervention bacterial contamination in terms of colony-forming units/CFU has drastically reduced after both interventions, which is validated by statistical significance. However, it was observed participants using disinfectant wipes as intervention had 2.07 times higher chance of having a low bacterial load which wasn't statistically significant. Conclusion Our study shows that with the use of any intervention from the above-mentioned interventions, bacterial load or bacterial contamination can be reduced significantly, thus pointing out that both ultraviolet radiation and disinfectant wipes are effective in reducing contamination of mobile phones. It was also found that male doctors have more bacterial load than females, which can be minimized by effectively changing behavioral habits.

Plasma-activated water: Candidate hand disinfectant for SARS-CoV-2 transmission disruption.

The global epidemic caused by SARS-CoV-2 has brought about worldwide burden and a sense of danger for more than two years, leading to a wide range of social, public health, economic and environmental issues. Self-inoculation through hands has been the primary way for environmental transmission of SARS-CoV-2. Plasma-activated water (PAW) has been reported as an effective, safe and environmentally friendly disinfectant against SARS-CoV-2. However, the inactivating effect of PAW on SARS-CoV-2 located on skin surface and its underlying mechanism of action have not been elucidated. In this study, PAW was prepared using an air-pressure plasma jet device. The antiviral efficiency of PAW1, PAW3, and PAW5 on the SARS-CoV-2 pseudovirus was 8.20 % (±2.88 %), 46.24 % (±1.79 %), and 91.71 % (±0.47 %), respectively. Additionally, determination of PAW's physicochemical properties, identification of major sterile effector in PAW, transmission electron microscopy analysis, malondialdehyde (MDA) assessment, SDS-PAGE, ELISA, and qPCR were conducted to reveal the virucidal mechanism of PAW. Our experimental results suggested that peroxynitrite, which was generated by the synergism of acidic environment and reactive species, was the major sterile effector of PAW. Furthermore, we found that PAW treatment significantly inactivated SARS-CoV-2 pseudovirus through the destruction of its structure of and the degradation of the viral RNA. Therefore, the possible mechanism for the structural destruction of SARS-COV-2 by PAW is through the action of peroxynitrite generated by the synergism of acidic environment and reactive species, which might react with and destroy the lipid envelope of SARS-CoV-2 pseudovirus. Nevertheless, further studies are required to shed light on the interaction mechanism of PAW-inherent RONS and viral components, and to confirm the determinant factors for virus inactivation of SARS-COV-2 by PAW. Therefore, PAW may be a candidate hand disinfectant used to disrupt the transmission of SARS-CoV-2.

Don't Rush with Your Brush: An In Vitro Study on Toothbrush Hygiene.

Aim: To evaluate the effectiveness of audiovisual (AV) aids in creating awareness of toothbrush hygiene. Materials and methods: This randomized trial study was conducted on 40 children aged 6-11 years. Children were given soft toothbrushes and then collected after brushing for 14 days. The toothbrushes were collected and sent to the laboratory for microbial culture evaluation. A questionnaire consisting of various questions regarding daily toothbrush hygiene practices was filled by the parents at the same time. After 14 days, brushes were collected, and the parents were shown an AV aid regarding toothbrush decontamination, parental awareness, and supervision. Those children were given new sets of toothbrushes and instructed to decontaminate them with chlorhexidine solution. After 14 days, the same questionnaire was filled out by the parents and toothbrushes were collected and immediately sent to the laboratory for microbial culture evaluation. Results: All the sampled toothbrushes had significant (p < 0.001) bacterial growth after 14 days of use. The use of disinfectant led to a 99.98% reduction in microbial colony counts. Hence, showed a significant result. Questionnaire analysis showed a positive parental approach toward maintaining toothbrush hygiene. Conclusion: Cleaning and disinfection of toothbrushes is crucial to stop the spread of disease since bacterial contamination cannot be 100% eliminated. AV aids can be effective tools for increasing awareness. Clinical significance: Through this study, we want to emphasize toothbrush hygiene and create awareness for the same through AV aid because a healthy toothbrush leads to healthy oral health. How to cite this article: Sharma S, Tandon S, Rai TS, et al. Don't Rush with Your Brush: An In Vitro Study on Toothbrush Hygiene. Int J Clin Pediatr Dent 2024;17(2):162-167.

Comparison of susceptibility of Pseudomonas aeruginosa isolated from keratitis to antibiotics and multipurpose disinfecting solutions.

PURPOSE: This study aimed to assess the susceptibility of ocular isolates of Pseudomonas aeruginosa to two multi-purpose disinfectant solutions (MPDS) and to determine if there was a relationship with resistance to antibiotics. METHODS: Twenty-three strains of P. aeruginosa isolated from microbial keratitis cases in Australia were utilized in this study. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of two commercially available MPDSs, Biotrue and cleadew MPS were determined. Additionally, the MIC of the strains to five antibiotics, ciprofloxacin, levofloxacin, gentamicin, ceftazidime, and imipenem, were analyzed. RESULTS: All strains were susceptible to 100 % of each of the MPDS. However, when MPDSs were diluted, cleadew MPS had significantly lower median MIC (median = 12.5 vs 25; p = 0.00008) and MBC (median = 25 vs 50; p = 0.0027) compared to Biotrue. All tested strains were susceptible to levofloxacin and gentamicin. Susceptibility rates to ciprofloxacin, imipenem, and ceftazidime were 52.2 %, 30.4 %, and 91.3 %, respectively. There were no significant relations between MIC or MBC to either MPDS and resistance to the antibiotics (p≧0.23). CONCLUSION: Both MPDSs were active against P. aeruginosa isolated from microbial keratitis in Australia. However, after dilution, cleadew MPS remained active against P. aeruginosa at lower concentrations. Certain strains of P. aeruginosa were resistant to imipenem, ceftazidime or ciprofloxacin. The lack of association of susceptibility to MPDS and antibiotics suggest that resistance to one did not predispose to resistance to the other.

An in-depth study on survival mechanism of bacterial isolates in disinfectants within the hospital environment.

Introduction: The emergence of disinfectant resistance has become a severe threat due to reduced effectiveness. This study was undertaken to determine how bacteria adapt to survive exposure to disinfectants in the busiest section of a tertiary care hospital in Varanasi, India. Methods: Four isolates (two Klebsiella pneumoniae, Kp1 and Kp2; two Pseudomonas aeruginosa, Pa1 and Pa2) were obtained from chlorhexidine (CHX)-based handwash during microbiological surveillance of "in-use disinfectants" in hospital. Six disinfectants [4% CHX, 2% glutaraldehyde, 7.5% hydrogen peroxide, 1% sodium hypochlorite and 0.1% benzalkonium chloride (BAC), and 70% ethyl alcohol] were tested against these four isolates to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Antibiotic profile, change in MIC on exposure to disinfectants and biofilm formation in the presence and absence of disinfectants was studied. Whole genome sequencing (WGS) was done to identify the resistance mechanisms. Result: The isolates showed the highest MBC/MIC ratio (4) against glutaraldehyde. Exposure to supra-inhibitory concentration of BAC for 21 days resulted in doubling of MIC/MBC. The majority (75%) of the isolates were multidrug resistant. All the isolates were strong biofilm producers. The reduction rate of biofilm formation decreased with an increase in the concentration of disinfectants (p = 0.05 for BAC). WGS revealed multiple AMR genes including bla DIM-1, disinfectant-resistant gene and efflux pump genes. Conclusion: The study emphasized the various adaptation strategies of these isolates for survival in disinfectant environment, thus posing a huge challenge for their control in the hospital environment.

Analysis of in vitro expression of virulence genes related to antibiotic and disinfectant resistance in Escherichia coli as an emerging periodontal pathogen.

The collective involvement of virulence markers of Escherichia coli as an emerging pathogen associated with periodontitis remains unexplained. This study aimed to implement an in vitro model of infection using a human epithelial cell line to determine the virulome expression related to the antibiotic and disinfectant resistance genotype and pulse field gel electrophoresis (PFGE) type in E. coli strains isolated from patients with periodontal diseases. We studied 100 strains of E. coli isolated from patients with gingivitis (n = 12), moderate periodontitis (n = 59), and chronic periodontitis (n = 29). The identification of E. coli and antibiotic and disinfectant resistance genes was performed through PCR. To promote the expression of virulence genes in the strains, an in vitro infection model was used in the human epithelial cell line A549. RNA was extracted using the QIAcube robotic equipment and reverse transcription to cDNA was performed using the QuantiTect reverse transcription kit (Qiagen). The determination of virulence gene expression was performed through real-time PCR. Overall, the most frequently expressed adhesion genes among the isolated strains of gingivitis, moderate periodontitis, and chronic periodontitis were fimH (48%), iha (37%), and papA (18%); those for toxins were usp (33%); those for iron acquisition were feoB (84%), fyuA (62%), irp-2 (61%), and iroN (35%); those for protectins were traT (50%), KpsMT (35%), and ompT (28%); and those for pathogenicity islands were malX (45%). The most common antibiotic and disinfectant resistance genes among gingivitis, moderate periodontitis, and chronic periodontitis strains were sul-2 (43%), blaSHV (47%), blaTEM (45%), tet(A) (41%), dfrA1 (32%), marR-marO (57%), and qacEA1 (79%). The findings revealed the existence of a wide distribution of virulome expression profiles related to the antibiotic and disinfectant resistance genotype and PFGE type in periodontal strains of E. coli. These findings may contribute toward improving the prevention and treatment measures for periodontal diseases associated with E. coli.

Evaluating the Expression of Efflux Pumps in Pseudomonas aeruginosa in Exposure to Sodium Dodecyl Sulfate, Didecyldimethylammonium Chloride, and Octenidine Dihydrochloride.

Emerging resistance of Gram-negative bacteria, including Pseudomonas aeruginosa, to commonly used detergents and disinfectant is encountering us with hazard. Inappropriate use of disinfectants has forced bacteria to gain resistance. The ability of bacteria to extrude substrates from the cellular interior to the external environment has enabled them to persist in exposure to toxic compounds, which is due to existence of transport proteins. Efflux pumps, in Gram-negative bacteria, are proteins responsible for exporting molecules outside of the cell, by crossing the two membranes. In this study, 40 P. aeruginosa strains from hospitals, clinics, and burn center laundries and 40 P. aeruginosa strains from urban laundries were collected. This study evaluated the minimum inhibitory concentration (MIC) level of sodium dodecyl sulfate (SDS), didecyldimethylammonium chloride (DDAC), and octenidine dihydrochloride (Od) in P. aeruginosa strains. The real-time PCR was carried out to evaluate the expression of MexAB-OprM, MexCD-OprJ, and MexXY-OprM efflux system. The obtained results indicated a higher MIC level for SDS, DDAC, and Od in medical laundries. The sub-MIC level of DDAC and Od increased the expression level of MexAB-OprM, MexCD-OprJ, and MexXY-OprM in P. aeruginosa strains, suggesting that efflux pumps contribute to disinfectant resistance in P. aeruginosa.

Antibacterial Activity of Brass against Antibiotic-Resistant Bacteria following Repeated Exposure to Hydrogen Peroxide/Peracetic Acid and Quaternary Ammonium Compounds.

Copper-containing materials are attracting attention as self-disinfecting surfaces, suitable for helping healthcare settings in reducing healthcare-associated infections. However, the impact of repeated exposure to disinfectants frequently used in biocleaning protocols on their antibacterial activity remains insufficiently characterized. This study aimed at evaluating the antibacterial efficiency of copper (positive control), a brass alloy (AB+®) and stainless steel (negative control) after repeated exposure to a quaternary ammonium compound and/or a mix of peracetic acid/hydrogen peroxide routinely used in healthcare settings. A panel of six antibiotic-resistant strains (clinical isolates) was selected for this assessment. After a short (5 min) exposure time, the copper and brass materials retained significantly better antibacterial efficiencies than stainless steel, regardless of the bacterial strain or disinfectant treatment considered. Moreover, post treatment with both disinfectant products, copper-containing materials still reached similar levels of antibacterial efficiency to those obtained before treatment. Antibiotic resistance mechanisms such as efflux pump overexpression did not impair the antibacterial efficiency of copper-containing materials, nor did the presence of one or several genes related to copper homeostasis/resistance. In light of these results, surfaces made out of copper and brass remain interesting tools in the fight against the dissemination of antibiotic-resistant strains that might cause healthcare-associated infections.

Assessing the Efficacy of Three Hatchery Disinfectants for the Inactivation of a Lake Sturgeon Herpesvirus (Family: Alloherpesviridae).

Infectious diseases are a leading cause of losses in the aquaculture industry and conservation programs globally. Simultaneously, infectious diseases pose a substantial risk to fish being hatchery-reared and released into natural habitats for conservation purposes, including the Great Lakes lake sturgeon (Acipenser fulvescens, i.e., GL-LST). Recently, an alloherpesvirus (lake sturgeon herpesvirus 2, i.e., LSHV-2) capable of inducing disease and/or mortality in adult and juvenile GL-LSTs was detected in two adult GL-LST populations. To begin developing disease prevention and/or control methods, in vitro experiments were designed to determine the susceptibility of LSHV-2 to disinfectants commonly used in hatchery and aquaculture facilities (Virkon®-Aquatic: potassium peroxymonosulfate; Ovadine®: polyvinylpyrrolidone iodine complex; and Perox-Aid®: hydrogen peroxide). Cultured LSHV-2 was exposed to each disinfectant at two concentrations (Virkon®-Aquatic: 0.5% and 1%; Ovadine®: 50 and 100 ppm; and Perox-Aid®: 500 and 1000 ppm) in duplicate for durations of 1, 10, and 30 min. Following exposure, the disinfectant was neutralized, and after a 14-day incubation period on a white sturgeon × lake sturgeon hybrid cell line (WSxLS), percent reduction was calculated by comparing the 50% tissue culture infectious doses (TCID50/mL) of the virus with and without disinfectant exposure. When exposed to Perox-Aid®, LSHV-2 percent reduction ranged from 58.7% to 99.5%. When exposed to Ovadine®, the percent reduction ranged from 99.4% to 100%. Lastly, the percent reduction when exposed to Virkon®-Aquatic was 100% for both concentrations and all timepoints. The results herein provide evidence that both Virkon®-Aquatic and Ovadine® are virucidal to LSHV-2 and may represent a means to reduce virus transmission risk under field settings.

A critical evaluation of contents, labeling, and cost of hand sanitizers marketed in India during COVID-19 pandemic.

Background: Antiseptics were introduced a long time ago, but their significance was noteworthy during the COVID-19 pandemic. Hand sanitizer plays a pivotal role as a preventive measure. Multiple national authorities have advocated for the application of Alcohol-Based Hand Sanitizers (ABHS). During the pandemic, a surge in demand and limited supply prompted numerous manufacturers to ramp up production. Consequently, it is imperative to scrutinize the composition, labeling, and price of hand sanitizers. Aims and Objective: To assess the contents, labeling, and price of hand sanitizers available in the Indian market. Methodology: Hand sanitizers, both online and offline, marketed in India between May 2019 and May 2022 were included. Hand sanitizers by local manufacturers without labeling were excluded. Contents and labeling of hand sanitizers were evaluated as per World Health Organization (WHO) recommendations. Price was assessed as a percentage cost variation. Result: Out of 79, the majority (98.73%) were ABHS, and 28.20% of them met the recommended criteria for "Adequate" alcohol concentration. Ethyl alcohol emerged as the most prevalent (69.23%), often accompanied by emollients, humectants, fragrances, and color additives. Notably, 69.62% of the hand sanitizers featured comprehensive labeling, while incomplete labels lacked essential details under "Warning and Cautions." The average price of hand sanitizers was Rs 505.11 ± 255.36. Conclusion: Choosing ABHS with appropriate alcohol concentrations in line with recommendations is crucial. To ensure the proper and safe use of hand sanitizers, individuals should follow the instructions provided on the product labels; both manufacturers and regulators are responsible for adhering to standards for hand sanitizers made available to the public.