Source Of Cross-contamination Research Articles

Assessment of the Hygienic Practices and Microbial Quality of Broiler Meat and its Contact Surfaces From Poultry Retail Outlet and Cold Room in Rivers State Nigeria

Poor hygiene and sanitary practices among poultry meat sellers can lead to the contamination of meat. This contamination can occur as a result of contamination from the contact surfaces in the cold room and retail outlet. The aim of the present study was to assess the sanitary quality of Broiler meat and its contact surfaces (apron, butcher hand, butcher table, bowl, butcher knife and weighing scale) in cold room and retail outlet. Swab samples were assessed for total bacteria count, total coliform count, total staphylococcus count and total fungal counts using Standard Microbiology methods. Mean Total viable count of each sample ranged from Log 10 cfu/cm2/g 3.64 to7.94 and 3.14 to 4.75 from the retail outlets and Cold-room respectively. Mean Total Staphylococcus count. of each sample ranged from Log 10 cfu/cm2/g 1.67to 4.67 and 2.01 to 3.87 from the retail outlets and Cold-room respectively. Counts from the retail outlets were significantly higher than counts in the cold room. Organisms isolated included ; Staphylococcus sp, Bacillus sp, Escherichia coli, Proteus sp, Salmonella sp, Aeromonas sp, Pseudomonas sp, Klebsiella sp and Enterobacter sp. Fungi isolated was Aspergillus sp, Saccharomyces sp, Penicillium sp and Rhodotorula sp. Antibiogram was carried out on the isolated organisms it was observed that Klebsiella sp and Enterobacter sp were resistant to most of the antibiotics used. In order to prevent cross-contamination of meat with isolated bacteria, appropriate cleaning and sanitization steps are required. According to the study, meat contact surfaces that were not thoroughly cleaned before usage, could function as a source of cross contamination. It is recommended that meat sellers especially in developing countries need proper education and training on good hygiene practice. Regulating agencies are also advised to ensure strict compliance by meat sellers to safety standards by embarking on routine inspection at retail outlets and market places.

Biofilm Formation From Listeria monocytogenes Isolated From Pangasius Fish-processing Plants

Biofilm formation of Listeria monocytogenes in food processing environments cause potential source of cross-contamination to foodstuffs; hence, the control of biofilm is currently addressed to find effective solutions for preventing biofilm formation or eliminating the established one. Forty-five strains of Listeria monocytogenes isolated from Pangasius fish-processing plants were studied for their capability to form a biofilm on 96-well microtiter plate by using the conventional crystal violet staining. Additionally, the inhibitory effect of biofilm formation by food additives including monascus pigment and ε-polylysine was examined. The average OD value showing biofilm mass of all 45 strains L. monocytogenes increased with an increasing temperature and time (p < 0.05). Monascus pigment and ε-polylysine significantly decreased biofilm formation by 80 ± 5.5% and 20 ± 5.9%, respectively, at the tested concentration (p < 0.05) Further, the effects of lysozyme (0.1 mg/mL) alone or in combination with slightly acidic hypochlorous water (SAHW) with 40 mg/L available chlorine or sodium hypochlorite (NaOCl) with 100 mg/L available chlorine against 7-d established biofilm of L. monocytogenes were investigated. The results indicated that slightly acidic hypochlorous water alone exhibited significant antibacterial activity (p < 0.05), decreasing the viable count by 5.2 ± 0.5 log CFU/mL. It seems that sequential treatment of lysozyme and SAHW showed an additional efficacy against biofilm of L. monocytogenes on polystyrene plate surface, reducing 70% of biomass of biofilm and 7.6 ± 0.3 log of biofilm viable cells (p < 0.05). Additionally, SAHW exhibited greater bactericidal activity against viable biofilm cells than NaOCl did. This result reveals that SAHW is a promising disinfectant agent against L. monocytogenes and the potential alternative to NaOCl in practice.

Contamination of UK firefighters personal protective equipment and workplaces

Firefighters’ personal protective equipment (PPE) is a potential source of chronic exposure to toxic contaminants commonly released from fires. These contaminants have also been found in fire stations. However, little research characterises the routes via which fire contaminants travel back to fire stations. The UK Firefighter Contamination Survey provides information on firefighters’ PPE provision, decontamination, and storage practices. All serving UK firefighters were eligible to take part in the survey, which comprised 64 questions. A total of 10,649 responses were included for analysis, accounting for roughly 24% of the UK’s firefighting workforce. Results revealed that most firefighters (84%) de-robe contaminated PPE/workwear after re-entering the appliance cab. There was a significant decreasing tendency to send PPE for cleaning after every incident with increasing seniority of role, length of service, and fire attendance frequency. Around one third of firefighters cleaned PPE after every incident. A number of issues were linked to external professional cleaning services, e.g. shrinkage, fit, turn-around time, and stock of reserve/pooled PPE. PPE storage was found to be a potential source of cross contamination, with almost half of firefighters (45%) indicating clean and dirty PPE is not stored separately. More than half of firefighters (57%) stored fire gloves (an item sent for professional decontamination by only 19% of firefighters, and never cleaned by 20%) within other items of PPE such as helmets, boots and tunic/trouser pockets. The survey’s results can be used to target gaps in decontamination measures within UK Fire and Rescue Services.

A Review on Significance of Public Health Issues Related to Poultry Campylobacteriosis

The goal of poultry industry worldwide is the production of safe food products, via efficient and goal-oriented health care to prevent the development of disease conditions in poultry. However, a several number of poultry diseases can negatively affects the breeding values and have the potential to be zoonotic and transmit the infections to humans such as campylobacteriosis. C. jejuni is highly prevalent in commercial poultry farms and act as major reservoirs of the infection. Horizontal transmission from the environment is considered to be the primary source of bacterial foodborne worldwide. The high prevalence of Campylobacter spp. in poultry meat is a result of several contamination and cross-contamination sources in the entire production chain. Recent investigations demonstrated that various stages of food processing in slaughterhouse and consumption of raw or undercooked poultry meat is considered the significant risk factor for human campylobacteriosis worldwide. Furthermore, survival factors such as biofilm formation and antimicrobial resistance, enable its persistence during food processing. On the other hand, the increase of multiple and multidrug-resistant Campylobacter worldwide is not only related to the over-consumption of antibiotics in human medicine, but also in poultry production chain as growth promotors and/or to treat and prevent bacterial infections. Antibiotic resistant Campylobacter presents an obvious and impending challenge to One Health. In the future, the consumer expectations for high standards quality of poultry products will strongly influence the production methods. This means that farmers, stockholders’, veterinarians, and all other partners involved in the production chain, will have to share more responsibilities and the cooperation should be intensified. This review represents an updated overview of the global epidemiology, the correlation of official control, the disease associated with food handler and the importance of food safety with respect to Campylobacteriosis.

Identification and Quantification of Staphylococcus Aureus in Saliva at Different Time Intervals Among Dental Personnel Wearing Surgical Masks During Sars Cov2- A Prospective Observational Study

Our world combats the rapid spread of Covid 19 by wearing face masks which have become the norm. But it's effect on oral microbiome is yet to be studied. Staphylococcus aureus is the leading cause of bacterial co-infection in Covid-19-affected patients worsening their prognosis. Dislodgement of this bacterium from the oral cavity is said to cause many systemic diseases. As dentists are more prone to an aerosolic environment and a potential source of cross-contamination, we intended to identify and quantify S. aureus in the saliva of dental personnel wearing surgical masks. Unstimulated whole saliva samples of 120 healthy dental professionals wearing surgical masks were cultured for S. aureus growth in Mannitol Salt Agar medium for 48 hours at 37°C. After 1 hour and 6 hours of mask usage, the number of colony-forming units counted. After 1 hour and 6 hours of mask usage, 56% and 52.5% demonstrated growth of S. aureus respectively. There was a statistically significant mean reduction of 1.61*103 colony forming units after 6 hours of mask usage. There is a reduction in the prevalence and number of colony-forming units of S. aureus in the unstimulated saliva of healthy dental professionals after 1 hour and 6 hours of surgical mask use. As a result, mask use not only controls the spread of Covid but may also aid in reducing the source and spread of S. aureus cross infection, lowering the risk of morbidity and mortality in diseased patients.

Characterization of Listeria monocytogenes biofilm formation kinetics and biofilm transfer to cantaloupe surfaces

Listeria monocytogenes biofilm is a consistent source of cross-contamination, both in housing storage and food processing environments. This study monitored the dynamic process of L. monocytogenes ST9 and ST87 biofilms, as well as their cross-contamination behaviors at various stages of formation. Scanning Electron Microscopy (SEM) captured the honeycomb-like structures and extracellular polymeric substances (EPS) during the biofilm formation. Confocal Laser Scanning Microscopy (CLSM) images illustrated that the ST87 strain formed a closed knitted chains network later than the ST9 strain. Moreover, structural parameters including bio-volume, mean thickness, porosity, and roughness could quantified the spatio-temporal differences of the biofilms. The transfer rates of biofilm cells to cantaloupes with the single contact had no significant difference at the initial adhesion, maturation, and dispersion stage (p > 0.05). Notably, the biofilm cells remained on the glass coupons when transferred to ten cantaloupe slices, indicating that biofilm cells transferred through cohesive failure. Meanwhile, the Logistic model could describe the transfer law of biofilm cells at different formation stages, as evaluated by Root Mean Square Error (RMSE) and R2adj. Additionally, the transfer rates were positively correlated with the hydrophobicity of L. monocytogenes ST87 biofilm cells measured by xylene. However, when the hydrophobicity of n-hexadecane was measured, the correlation was negative. This study illustrated the spatial and temporal differences during L. monocytogenes biofilms formation, and the transfer and residual of biofilm cells after a single and ten successive contacts at the specific stages. Our findings help in the quantitative microbiological risk assessment of fresh produce.

Assessment of drinking water access and household water insecurity: A cross sectional study in three rural communities of the Menoua division, West Cameroon

Water is a physiological need, key for survival. In limited water access situations, health, well-being, and productivity of households are negatively affected. Water insecurity refers to when access to adequate amount of clean water does not occur all the times for household members to lead a healthy and active life. A cross sectional study was conducted with 121 women from three rural communities in the West-Cameroon, to assess water insecurity experience and its correlation with related indicators. Specifically, this study aimed to: examine drinking water access by time spent on collection and distance to the water source, determine the prevalence of household water insecurity, and examine the relationship between water insecurity and diarrhea as well as drinking water access-related indicators. The main sources of drinking water included boreholes (69%), wells (13%), and rivers (12%). Each household spent an average total amount of 3 hours on water fetching. The mean duration of the drinking water stored was 4 days, after which the process was repeated. The majority of households (94.2%) were water insecure (total WATINE-17 score ≥1). About 61% reported drinking less water than they felt they should and 32% of them, said they had to drink dirty water. Water insecurity mean score was higher in households who reported diarrhea among their 0–5 years old children than their counterparts (p = 0.008). This study highlights the problem that good access to improved water source still represents in low-resource households of rural areas, with the subsequent complex interactions on women and children’s health. Future research on water management and storage is warranted to understand the sources of cross-contamination and to identify the potential points of intervention to ensure safe drinking water for rural households. Policies should be designed in order to incorporate systematic household water insecurity measurement in monitoring advancement towards 2030 SDG.

ATTITUDE TOWARDS COVID-19 IN DENTAL COLLEGE POPULATION: A CROSS SECTIONAL STUDY.

Introduction: In this COVID -19 pandemic dentists are at high risk of cross-infection. The dental practice is a source of cross contamination in the absence of adequate preventive measures. As COVID -19 is highly contagious and use of air rotors adds to air born route for transmission and dentist's proximity to the oropharyngeal area of the patient, a dental professional is always at higher risk. Therefore all the dental students and professionals should be competent with knowledge and must be aware of precautionary methods, social distancing, sanitization and vaccination. Aim: The present study is aimed to assess the attitude towards COVID-19 in dental college population Materials &amp; Methods: This study was conducted among 200 participants, the faculties and students in a dental college. A ten questions multiple choice questionnaire form was prepared on effect of COVID-19 on participant's life and distributed among the participants who were divided into two groups as faculty &amp; students, in the dental college and their response was tabulated and analyzed. Results: The results of this study suggested that majority of participants of both the groups strictly followed precautionary measures, followed social distancing, taken both the doses of vaccination and showed positive attitude towards prevention of further spread of corona virus. Conclusion: The participants in this study seemed to be aware of the detrimental effects of COVID-19 and had good knowledge, attitude and selfcare practice, which are necessary in preventing the spread of COVID-19.

Stability and Antibiofilm Efficiency of Slightly Acidic Electrolyzed Water Against Mixed-Species of Listeria monocytogenes and Staphylococcus aureus.

In the natural environment, most microorganisms live in mixed-species biofilms, in which the metabolism and growth of organisms are different from that in single-species biofilms. Adhesive bacteria and their biofilms on the surface of food processing equipment are the sources of cross-contamination, leading to the risk for humans. Slightly acidic electrolyzed water (SAEW) has been proposed as a novel sanitizer in the food and agriculture industry. In this study, we investigated the changes in the physical properties of SAEW under different conditions and the disinfection abilities of SAEW against spore-forming and non-spore-forming pathogens. Furthermore, we examined the disinfection abilities of SAEW after 12 months of shelf life on a mixed-species biofilm of Listeria monocytogenes Scott A and Staphylococcus aureus. The results showed that SAEW at 30 and 50 ppm achieved all-kill of the spore-forming pathogen Bacillus cereus within 30 s. Changes in the ACC and pH of the produced SAEW were generally affected by the storage conditions. Both spore-forming and non-spore-forming pathogens were not detected under treatment with 50 ppm SAEW for 5 min under HDPE-closed conditions throughout the whole storage period. Moreover, 25 mg/L SAEW can inactivate L. monocytogenes Scott A and S. aureus biofilm cells in ~2.45 and 2.57 log CFU/mL in biofilms within 5-min treatment. However, the decline of the two bacteria in the mixed-species biofilm was 1.95 and 1.43 log CFU/mL, respectively. The changes in the cell membrane permeability of the mixed-species biofilm under treatment with SAEW were observed by using atomic force microscopy and confocal laser scanning microscopy. L. monocytogenes Scott A was more sensitive to SAEW in the mixed-species biofilm cells. These findings exhibited strong antibiofilm activities of SAEW in impairing biofilm cell membranes, decreasing cell density, and eliminating biofilm, which suggest that SAEW is an excellent antibacterial agent in the food processing industries.

How to Make Personal Protective Equipment Spontaneously and Continuously Antimicrobial (Incorporating Oxidase-like Catalysts).

The inability of commercial personal protective equipment (PPE) to inactivate microbes in the droplets/aerosols they intercept makes used PPE a potential source of cross-contamination. To make PPE spontaneously and continuously antimicrobial, we incorporate PPE with oxidase-like catalysts, which efficiently convert O2 into reactive oxygen species (ROS) without requiring any externally applied stimulus. Using a single-atom catalyst (SAC) nanoparticle containing atomically dispersed copper atoms as the reactive centers (Cu-SAC) and a silver-palladium bimetallic alloy nanoparticle (AgPd0.38) as models for oxidase-like catalysts, we show that the incorporation of oxidase-like catalysts enables PPE to inactivate bacteria in the droplets/aerosols they intercept without requiring any externally applied stimulus. Notably, this approach works both for PPE that are fibrous and woven such as a commercial KN95 facial respirator and for those made of solid plastics such as an apron. This work suggests a feasible and global approach for preventing PPE from spreading infectious diseases.

Challenges in setting permitted daily exposure limits for pharmaceuticals: A review

When more than one drug is manufactured at a shared facility or equipment in pharmaceutical manufacturing, the potential carry-over of the retained residue of existing drug product on product contact parts of the equipment to the next product can be a source of cross contamination. Permitted daily exposure (PDE) is derived based on the complete nonclinical and clinical data available and is a dose that is unlikely to cause adverse effects if an individual is exposed, by any route, at or below this dose every day over a lifetime. The objective was to present a comprehensive review of available scientific knowledge for derivation of PDE. PubMed and ScienceDirect databases were searched using keywords "PDE" and "pharmaceuticals" and all the relevant literature up to March 2021 was reviewed. We have also calculated PDEs for Tobramycin (CAS No. 32986-56-4) and Acetyl Salicylic Acid (ASA, CAS No. 50-78-2). This research will be useful for scientists working in the PDE domain. The given examples emphasize the importance of use of human data in calculating PDE. The duty of the risk assessor entrusted with setting PDEs is to derive a data driven, scientifically justified value that is safe for patients, while avoiding unjustified conservativeness that puts unnecessary burden on manufacturing.

Nasopharyngeal temperature probes: is South Africa’s current decontamination process adequate?

Background: The standard practice in many institutions incorporates nasopharyngeal probes for temperature monitoring in patients undergoing general anaesthesia. Current disinfection guidelines for these devices are not clear and they are poorly adhered to. In South Africa, these temperature probes are reused and subjected to unstandardized decontamination processes. This study sought to investigate nasopharyngeal temperature probes as possible source for cross-contamination, and assess the efficacy of current disinfection practices for these probes.&#x0D; Methodology: This was an analytical double-blind randomized study of 4 different disinfection protocols for 48 nasopharyngeal temperature probes. The probes were randomized to disinfection protocols that included water wash, dry wipe, hibitane® and cidex® wash. After decontamination by the respective protocol, the probes were aseptically placed in nutrient broths, manually agitated and removed, and the broths were then inoculated onto blood agar plates. After 48 hours of aerobic culture incubation at 37oC, plates were examined for growth and bacteria identified using automated bioMérieux Vitek-2 microbial identification system. Chi square and logistic regression analyses were used to assess bacterial contamination rates of the disinfected probes, in order to infer the efficacy of the decontamination processes.&#x0D; Results: Of the 48 nasopharyngeal temperature probes disinfected by the different protocols, 22 (45.8%) had bacterial contamination, with frequency of isolation for coagulase negative staphylococci (44%), Bacillus cereus (20%), Staphylococcus aureus (10%), Enterobacter cloaca (7%), Pseudomonas aeruginosa (4%), Pseudomonas fluorescens (3%), Acinetobacter baumannii (3%), amongst other bacterial species. Dry wipe, and water and soap methods, had statistically significant higher contamination rates of 83.3% and 66.7% than hibitane® and cidex®, with 25.0% and 8.3% respectively (X2=17.69, p&lt;0.0001). The odds of contamination when water-wipe was used as a cleaning method was 6 times (OR=6.000; 95% CI=1.018-35.374, p=0.048) that of hibitane® method while the odds for dry-wipe was 15 times (OR=15.000, 95% CI=2.024-111.174, p=0.008). No statistically significant difference was observed in the contamination rates between cidex® and hibitane® disinfection methods(OR=0.273, 95% CI=0.024-3.093, p=0.294).&#x0D; Conclusion: These data shows that nasopharyngeal temperature probes are possible source of cross-contamination and pathogen transmission due to inadequacy of the decontamination processes for these temperature probes.

A disposable envelope for video-assisted intubating stylet during tracheal intubation in COVID-19 pandemic.

DEAR EDITOR, Tracheal intubation of patients with coronavirus disease-19 (COVID-19) is a potentially aerosol-generating procedure that requires a careful and efficient approach to ensure the safety of both patients and healthcare providers.1 Many guidelines recommend the use of video-assisted intubating devices (VAIDs) to increase the operator’s distance from the patient’s airway and the chance of first-pass success.2 When donned with personal protective equipment (PPE), the first-pass success rate and intubation time with VAIDs are not affected when compared with a direct laryngoscope.3 A VAID is usually a video laryngoscope or video intubating stylet. It mainly composes of four parts: monitor, main body, handle and its cable, and a blade or stylet. Compared with the traditional direct laryngoscope, VAIDs can be expensive to use and maintain with concerns for cost-effectiveness, quality, and environmental impact from the disposable blades or stylets. Moreover, the nondisposable parts of the equipment such as the handle, cable, and main body can be potential sources of cross-contamination if strict decontamination is not followed.4 An innovative and economic approach is to cover the entire VAID device with a disposable envelope, including the optic stylet, handle, and monitor during airway management. We explored this concept using a video optic intubating stylet (disposcope endoscope). An elastic, flexible heat-shrunk tube was designed and manufactured, which the optic style can be inserted easily without any lubricant. The end tip of the heat-shrunk tube consists of a transparent acrylic lens that does not block or in any way compromise the light and camera of the optic stylet. The handle is then covered by a disposable plastic drape. This setup ensures the video optic stylet is fully shielded during airway management or tracheal intubation. The demonstration is provided by supplementary appendix (https://youtu.be/XBh1W5Rki8k). After each procedure, the heat-shrunk tube and the plastic handle drape can be removed and disposed of. The heat-shrunk tube is very thin (thickness in 1.5 mm). After its fitting over the optic stylet, it still allows the loading of endotracheal tube equal to or larger than 5.5 ID in size. A pediatric optic stylet with a matching heat-shrunk tube is also developed, and it can be loaded with an endotracheal tube equal to or larger than 3 ID in size. The COVID-19 pandemic is not likely going to disappear and can potentially become a seasonal or endemic foe. Furthermore, infected asymptomatic and mildly symptomatic still confer a high risk of transmission. Routine and emergent airway management thus poses the risk of potential exposure and infection to healthcare workers during the procedure and postoperative decontamination.5 An affordable and practical disposable barrier method to the video-assisted airway device to protect the operators and reduce the associated cost.

Heresy or Breakthrough: Fibre Optic Cleaning Without Inspection and Call for an &amp;quot;Open Architecture&amp;quot; Fibre Optic Precision Cleaning Procedure

A new inspection device defines the three-dimensional nature of connector surface areas and potential debris in unseen and previously uncharacterized surfaces. Inspection and cleaning procedures emerged in 2006. There are limitations within these that are resolved with color digital photography of the three-dimensional surfaces rather than the limited two-dimensional perspectives of IEC 61300-3-35. The result is an update of cleaning processes that (only) consider 15-20% of a two-dimensional diameter of the area commonly termed an horizontal ‘end face’. Advanced inspection reveals not only the remaining ‘horizontal end face’, but also introduces and adds vertical surfaces to the ‘end face’ that result in a logical, obvious, and heretofore disregarded three-dimensional structure. (Figure 1) As well, the advanced inspection device reveals connector adapters which are commonly understood to be a source of cross-contamination of one connection to the other. Until this time, there has been no practical means to view connection adapters and alignment sleeve components. (Figure 2) All of these various surfaces may have debris that currently area not considered and are soil points that may induce cross-contamination. These surfaces, as to present an accurate definition of the connector, require redefinition from two dimensions to three. The results of this logical advance bring enhanced cleaning procedures, new tools, and more reliable transmissions for all fiber optic deployments. This means than instead of multiple recleaning, first time cleaning is more possible and successful deployments more probable. When existing standards were first written in 2006, there was less need for precision cleaning and inspection of these surfaces. As fibre optic capacities and transmission speeds have increased, awareness of the three-dimensional nature of connector surfaces leads network designers, installers, and researchers to adopt a higher standard of inspection and precision cleaning to meet the ever-advancing sciences of fibre optic transmission of all types. Each is equally mission critical and one open architecture cleaning procedure follows the crafts person and contractor and is written into specific network designs. In so doing, the network design itself becomes a training tool for subsequent deployments. A new inspection device defines the three-dimensional nature of connector areas and potential debris in unseen and previously uncharacterized surfaces. With IEC 61300-3-35, inspection and cleaning procedures emerged. There are limitations. One procedure is possible: adaptable to all cleaning products in a vendor neutral way.

Influence of Free Chlorine and Contact Time on the Reduction of Salmonella Cross-Contamination of Tomatoes in a Model Flume System

The process of washing tomatoes in dump (flume) tanks has been identified as a potential source of cross-contamination. This study's objective was to assess the potential for Salmonella enterica cross-contamination at various inoculation levels in the presence of free chlorine (HOCl) and organic matter. Uninoculated tomatoes were introduced into a laboratory-based model flume containing tomatoes inoculated with a cocktail of five rifampin-resistant S. enterica serovars at 104, 106, or 108 CFU per tomato in water containing 0 or 25 mg/L HOCl and 0 or 300 mg/L chemical oxygen demand (COD). Uninoculated tomatoes exposed to the inoculated tomatoes were removed from the water after 5, 30, 60, and 120 s and placed in bags containing tryptic soy broth supplemented with rifampin and 0.1% sodium thiosulfate. Following incubation, enrichment cultures were plated on tryptic soy agar supplemented with rifampin and xylose lysine deoxycholate agar to determine the presence of Salmonella. HOCl and pH were measured before and after each trial. The HOCl in water containing 300 mg/L COD significantly declined (P ≤ 0.05) by the end of each 120-s trial, most likely due to the increased demand for the oxidant. Higher inoculum levels and lower HOCl concentrations were significant factors (P ≤ 0.05) that contributed to increased cross-contamination. At 25 mg/L HOCl, no Salmonella was recovered under all conditions from uninoculated tomatoes exposed to tomatoes inoculated at 104 CFU per tomato. When the inoculum was increased to 106 and 108 CFU per tomato, cross-contamination was observed, independent of COD levels. The results from this study indicate that the currently required sanitizer concentration (e.g., 100 or 150 mg/L) for flume water may be higher than necessary and warrants reevaluation.

Microbial contamination of resin composites inside their dispensers: An increased risk of cross-infection?

ObjectivesTo evaluate the effects of microorganisms’ contamination inside the dispensing syringes of different types of resin-based composites (RBCs). MethodsThis study encompassed two sections. First, an anonymous electronic survey was submitted via Google forms to Italian dentists to acquire information about composite handling during clinical procedures. Then, a bench test was performed on nanohybrid RBCs differing in matrix chemistry and fillers [FiltekTM Supreme XTE (3MTM); Venus Pearl (Kulzer GmbH); Admira Fusion x-tra (Voco)] to evaluate the microbial viability on their surfaces with/out photocuring. Uncured RBCs were exposed to standardized inocula of Streptococcus Mutans, Candida Albicans, Lactobacillus Rhamnosus, or mixt plaque in an in vitro model reproducing clinical restorative procedures. Half of the RBC specimens were cured after exposure. Microbial viability was assessed using an MTT-based test. Statistical analysis included three-way ANOVA and Tukey's tests (p<0.05). ResultsAmong 300 dentists completing the survey, the majority declared to use the spatula to carry the RBCs from the syringe to the dental cavity (50% same spatula; 35% two spatulas). However, 80% of respondents had personal feelings that using one spatula could be a source of cross-contamination. In vitro results using one spatula showed microbial contamination of all RBCs after one hour of storage. The contamination levels depended on the used strain and RBC type (p<0.0001), but photocuring did not reduce contamination (p = 0.2992). ConclusionsMicrobial species’ viability on uncured RBCs and after photocuring shows the existence of a considerable risk of cross-infection. Clinical procedures in Restorative Dentistry need to acknowledge and to reduce such risk during RBCs handling. Clinical significanceDentists must be aware of the possibility of cross-infection during restorative procedures, especially when the same spatula is repeatedly used for placing RBC in the cavity.

Cross-Contamination as a Problem in Collection and Analysis of Environmental Samples Containing Microplastics—A Review

Research conducted so far on the presence of microplastics in the environment shows that these items are ubiquitous pollutants and therefore constitute an inherent part of our lives. This constitutes a significant problem in many aspects, and one of them is the correct identification of microplastics in environmental samples. Environmental samples can be easily contaminated by plastic microparticles from other sources if proper precautions are not taken during sampling and analysis. The consequence of not taking this cross-contamination into account when analysing the results may be their significant overestimation. This review aims to draw attention to the problem of cross-contamination that accompanies the collection and analysis of samples for the presence of microplastics, and to discuss this issue in a comprehensive manner. The article indicates potential sources of cross-contamination, lists the mitigation methods, and describes the possibilities of assessing this type of contamination. Moreover, the review examines how cross-contamination control appears in practice, based on the available literature data.

Cross-contamination in molecular laboratories: A challenge to COVID-19 testing in Bangladesh

Rapid and accurate laboratory diagnosis of SARS-CoV-2 infection is crucial for the management of COVID-19 patients and control of the spread of the virus. At the start of the COVID-19 pandemic, Bangladesh had only one government molecular laboratory where real-time RT-PCR will be performed to diagnose SARS-CoV-2 infection. With the increasing number of suspected cases requiring confirmation diagnostic testing, there was a requirement to quickly expand capacity for large-scale testing. The government of Bangladesh established over 100 molecular laboratories within one year to test COVID-19. To fulfil the requirement for expanded testing, the government was compelled to recruit laboratory employees with inadequate experience, technical knowledge, and skills in molecular assays, particularly in processing specimens, interpreting results, recognizing errors, and troubleshooting. As a result, the risk of diagnostic errors, such as cross-contamination, is increased, as is that the risk of false-positive results, which might risk the patient’s health and undermine the efficacy of public health policies, public health response, surveillance programs, and restrictive measures aimed toward containing the outbreak. This review article aims to explain different sources of crosscontamination in the COVID-19 RT-PCR laboratories and the way to forestall them in efficient and practical ways.

Bacterial contamination of the smartphones of healthcare workers in a German tertiary-care hospital before and during the COVID-19 pandemic

BackgroundAssuming that hygiene measures have improved significantly due to COVID-19, we aimed to investigate bacterial colonization on smartphones (SPs) owned by healthcare workers (HCWs) before and during the pandemic. MethodsEmploying a before-and-after study design, randomly selected HCWs were included. Devices underwent sampling under real-life conditions, without prior manipulation. Swabs were collected in 2012 (pre-pandemic) and 2021 to determine microbial colonization. Isolates were identified by MALDI-TOF mass spectrometry and underwent microbiological susceptibility testing. ResultsThe final analysis included 295 HCWs (67% female, mean age 34 years) from 26 wards. Bacterial contamination was present on 293 of 295 SP screens (99.3%). The proportion of clinically relevant bacterial pathogens (eg Staphylococcus aureus, enterococci, Enterobacterales, non-fermenting bacteria) ranged from 21.2% in 2012 to 39.8% in 2021. Resistance profiles revealed a proportion of multidrug-resistant bacteria such as MRSA and VRE of less than 2%. The comparison of before-and-after sampling showed a significant increase in smartphone use during work from 2012 to 2021 with a simultaneous increase in cleaning intensity, probably as a result of the COVID-19 pandemic. ConclusionsBacterial contamination of SPs within the hospital is of concern and can serve as a source of cross-contamination. Hence, in addition to excellent hand hygiene, SPs must be carefully disinfected after handling in healthcare. Behavioral changes related to the COVID-19 pandemic could have a significant impact if implemented sustainably in everyday clinical practice.

Mobile phones of anesthesiologists as reservoirs of nosocomial bacteria in a quaternary teaching hospital: an observational study

BackgroundMobile phones in hospital settings have been identified as an important source of cross-contamination because of the low frequency with which mobile phones are cleaned by health workers and cyclical contamination of the hands and face. The aim of this study was to investigate whether the mobile phones of the anesthesia team at a teaching hospital are potential reservoirs of nosocomial bacteria. In addition, differences in device sanitization and hand hygiene habits between attending and resident anesthesiologists were correlated with mobile phone colonization. MethodsA prevalence study was conducted over a 6-month period from 2017 to 2018 that involved the collection of samples from the mobile phones of the anesthesiology team and culturing for surveillance. A questionnaire was administered to assess the mobile phone sanitization and hand washing routines of the anesthesia team in specific situations. ResultsBacterial contamination was detected for 86 of the 128 mobile phones examined (67.2%). A greater presence of Micrococcus spp. on devices was correlated with a higher frequency of mobile phone use (p=0.003) and a lower frequency of sanitization (p=0.003). The presence of bacteria was increased on the mobile phones of professionals who did not perform handwashing after tracheal intubation (p=0.003). ConclusionHand hygiene and device sanitization habits were more important than the use behavior, as a higher presence of bacteria correlated with poorer hygiene habits. Furthermore, handwashing is the best approach to prevent serious colonization of mobile devices and the possible transmission of pathogens to patients under the care of anesthesiologists.