Microbial monitoring of the hospital environment: why and how?

Prevalence of multi-drug resistant bacteria in intensive care units at Tripoli University Hospital, Tripoli, Libya

Among hospitalized patients worldwide, infections caused by multidrug-resistant (MDR) bacteria are a major cause of morbidity and mortality. This study aimed to isolate MDR bacteria from five intensive care units (ICUs) at Tripoli University Hospital (TUH). A prospective cross-sectional study was conducted over a seven-month period (September 2022 to March 2023) across five ICUs at TUH. A total of 197 swabs were collected from Patients', healthcare workers' and ICUs equipment. Samples collected from patients were nasal swabs, oral cavity swabs, hand swabs, sputum specimens, skin swabs, umbilical venous catheter swabs, and around cannula. Swabs collected from health care workers were nasal swabs, whereas ICUs equipment's samples were from endotracheal tubes, oxygen masks, and neonatal incubators. Identification and antimicrobial susceptibility test was confirmed by using MicroScan auto SCAN 4 (Beckman Coulter). The most frequent strains were Gram negative bacilli 113 (57.4%) with the predominance of Acinetobacter baumannii 50/113 (44%) followed by Klebsiella pneumoniae 44/113 (40%) and Pseudomonas aeruginosa 6/113 (5.3%). The total Gram positive bacterial strains isolated were 84 (42.6%), coagulase negative Staphylococci 55 (66%) with MDRs (89%) were the most common isolates followed by Staphylococcus aureus 15 (17.8%). Different antibiotics were used against these isolates; Gram- negative isolates showed high resistance rates to ceftazidime, gentamicin, amikacin and ertapenem. A. baumannii were the most frequent MDROs (94%), and the highest resistance rates in Gram-positive strains were observed toward ampicillin, oxacillin, ampicillin/sulbactam and Cefoxitin, representing 90% of total MDR Gram-positive isolates. ESBL and MRS were identified in most of strains. The prevalence of antibiotic resistance was high for both Gram negative and Gram positive isolates. This prevalence requires strict infection prevention and control intervention, continuous monitoring, implementation of effective antibiotic stewardship, immediate, concerted and collaborative action to monitor its prevalence and spread in the hospital.

Trends in viable microbial bioburden on surfaces within a paediatric bone marrow transplant unit

BACKGROUND

Despite their role being historically overlooked, environmental surfaces have been shown to play a key role in the transmission of pathogens causative of healthcare-associated infection. To guide infection prevention and control (IPC) interventions and inform clinical risk assessments, more needs to be known about microbial surface bioburdens.

AIM

To identify the trends in culturable bacterial contamination across communal touch sites over time in a hospital setting.

METHODS

Swab samples were collected over nine weeks from 22 communal touch sites in a paediatric bone marrow transplant unit. Samples were cultured on Columbia blood agar and aerobic colony counts (ACC) per 100 cm2 were established for each site. Individual colony morphologies were grouped and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or 16s rDNA sequencing.

FINDINGS

Highest mean counts were observed for sites associated with ward management activity and computer devices (3.29 and 2.97 ACC/100 cm2 respectively). A nurses' station keyboard had high mean ACC/100 cm2 counts (10.67) and diversity, while laundry controls had high mean ACC/100 cm2 counts (4.70) and low diversity. Micrococcus luteus was identified in all sampling groups. Clinical staff usage sites were contaminated with similar proportions of skin and environmental flora (52.19-46.59% respectively), but sites associated with parental activities were predominantly contaminated by environmental microflora (86.53%).

CONCLUSION

The trends observed suggest patterns in microbial loading based on site activities, surface types and user groups. Improved understanding of environmental surface contamination could help support results interpretation and IPC interventions, improving patient safety.

Is ultraviolet light disinfection fit to be the future standard for the disinfection of flexible endoscopes without a working channel?

OBJECTIVE

To investigate colony-forming unit (CFU) reduction on contaminated flexible endoscopes (FEs) without a working channel after UV-C light disinfection, compared to the current disinfection method with the endoscope washer disinfector (EWD).

DESIGN, SETTING AND PARTICIPANTS

After pharyngolaryngoscopy, a manual pre-cleaning with tap water was performed. A culture was then collected by rolling the distal 8-10 cm of the FE over an Agar plate. The FE was disinfected using the D60 (60-s disinfection process with UV-C light) or the EWD (gold standard reprocessing process with water and chemicals). Another culture was then taken. After incubation, a CFU count was performed.

RESULTS

A total of 200 FEs without a working channel were divided equally between the two disinfection groups. After clinical use and manual pre-cleaning, 84 of the 100 (84.0%) (UV-C light group) and 79 of the 100 (79.0%) (EWD) FEs were contaminated with at least 1 CFU. FEs that showed no contamination after use were excluded from further analysis. After disinfection with UV-C light, 72 (85.7%) FEs showed no contamination (i.e., 0 CFUs) versus 66 (83.5%) FEs after reprocessing with the EWD.

CONCLUSION

There is no difference in CFUs reduction on contaminated FEs without a working channel between UV-C light disinfection and the current gold standard, the EWD.

Preventing Multidrug-Resistant Bacterial Transmission in the Intensive Care Unit with a Comprehensive Approach: A Policymaking Manual

Patients referred to intensive care units (ICU) commonly contract infections caused by multidrug-resistant (MDR) bacteria, which are typically linked to complications and high mortality. There are numerous independent factors that are associated with the transmission of these pathogens in the ICU. Preventive multilevel measures that target these factors are of great importance in order to break the chain of transmission. In this review, we aim to provide essential guidance for the development of robust prevention strategies, ultimately ensuring the safety and well-being of patients and healthcare workers in the ICU. We discuss the role of ICU personnel in cross-contamination, existing preventative measures, novel technologies, and strategies employed, along with antimicrobial surveillance and stewardship (AMSS) programs, to construct effective and thoroughly described policy recommendations. By adopting a multifaceted approach that combines targeted interventions with broader preventive strategies, healthcare facilities can create a more coherent line of defense against the spread of MDR pathogens. These recommendations are evidence-based, practical, and aligned with the needs and realities of the ICU setting. In conclusion, this comprehensive review offers a blueprint for mitigating the risk of MDR bacterial transmission in the ICU, advocating for an evidence-based, multifaceted approach.

Safe infant feeding in healthcare facilities: Assessment of infection prevention and control conditions and behaviors in India, Malawi, and Tanzania

Infants need to receive care in environments that limit their exposure to pathogens. Inadequate water, sanitation, and hygiene (WASH) environments and suboptimal infection prevention and control practices in healthcare settings contribute to the burden of healthcare-associated infections, which are particularly high in low-income settings. Specific research is needed to understand infant feeding preparation in healthcare settings, a task involving multiple behaviors that can introduce pathogens and negatively impact health. To understand feeding preparation practices and potential risks, and to inform strategies for improvement, we assessed facility WASH environments and observed infant feeding preparation practices across 12 facilities in India, Malawi, and Tanzania serving newborn infants. Research was embedded within the Low Birthweight Infant Feeding Exploration (LIFE) observational cohort study, which documented feeding practices and growth patterns to inform feeding interventions. We assessed WASH-related environments and feeding policies of all 12 facilities involved in the LIFE study. Additionally, we used a guidance-informed tool to carry out 27 feeding preparation observations across 9 facilities, enabling assessment of 270 total behaviors. All facilities had 'improved' water and sanitation services. Only 50% had written procedures for preparing expressed breastmilk; 50% had written procedures for cleaning, drying, and storage of infant feeding implements; and 33% had written procedures for preparing infant formula. Among 270 behaviors assessed across the 27 feeding preparation observations, 46 (17.0%) practices were carried out sub-optimally, including preparers not handwashing prior to preparation, and cleaning, drying, and storing of feeding implements in ways that do not effectively prevent contamination. While further research is needed to improve assessment tools and to identify specific microbial risks of the suboptimal behaviors identified, the evidence generated is sufficient to justify investment in developing guidance and programing to strengthen infant feeding preparation practices to ensure optimal newborn health.

Detection of hospital environmental contamination during SARS-CoV-2 Omicron predominance using a highly sensitive air sampling device

Background and objectives

The high transmissibility of SARS-CoV-2 has exposed weaknesses in our infection control and detection measures, particularly in healthcare settings. Aerial sampling has evolved from passive impact filters to active sampling using negative pressure to expose culture substrate for virus detection. We evaluated the effectiveness of an active air sampling device as a potential surveillance system in detecting hospital pathogens, for augmenting containment measures to prevent nosocomial transmission, using SARS-CoV-2 as a surrogate.

Methods

We conducted air sampling in a hospital environment using the AerosolSense^TM air sampling device and compared it with surface swabs for their capacity to detect SARS-CoV-2.

Results

When combined with RT-qPCR detection, we found the device provided consistent SARS-CoV-2 detection, compared to surface sampling, in as little as 2 h of sampling time. The device also showed that it can identify minute quantities of SARS-CoV-2 in designated "clean areas" and through a N95 mask, indicating good surveillance capacity and sensitivity of the device in hospital settings.

Conclusion

Active air sampling was shown to be a sensitive surveillance system in healthcare settings. Findings from this study can also be applied in an organism agnostic manner for surveillance in the hospital, improving our ability to contain and prevent nosocomial outbreaks.

Evaluating the environmental microbiota across four National Health Service hospitals within England

Hospital surfaces contaminated with microbial soiling, such as dry surface biofilms (DSBs), can act as a reservoir for pathogenic micro-organisms, and inhibit their detection and removal during routine cleaning. Studies have recognized that such increases in bioburden can hinder the impact of disinfectants and mask the detection of potential pathogens. Cleanliness within healthcare settings is often determined through routine culture-based analysis, whereby surfaces that exhibit >2.5 colony-forming units (CFU) per cm² pose a risk to patient health; therefore, any underestimation could have detrimental effects. This study quantified microbial growth on high-touch surfaces in four hospitals in England over 19 months. This was achieved using environmental swabs to sample a variety of surfaces within close proximity of the patient, and plating these on to non-specific low nutrient detection agar. The presence of DSBs on surfaces physically removed from the environment was confirmed using real-time imaging through episcopic differential interference contrast microscopy combined with epifluorescence. Approximately two-thirds of surfaces tested exceeded the limit for cleanliness (median 2230 CFU/cm²), whilst 83% of surfaces imaged with BacLight LIVE/DEAD staining confirmed traces of biofilm. Differences in infection control methods, such as choice of surface disinfectants and cleaning personnel, were not reflected in the microbial variation observed and resulting risk to patients. This highlights a potential limitation in the effectiveness of the current standards for all hospital cleaning, and further development using representative clinical data is required to overcome this limitation.

Environmental bacterial and fungal contamination in high touch surfaces and indoor air of a paediatric intensive care unit in Maputo Central Hospital, Mozambique in 2018

Background

The hospital environment serves as a reservoir of microorganisms which may be associated with healthcare-associated infections (HCAI). The study of environmental contamination with microorganisms is a method for the assessment of hospital environmental hygiene. We sought to evaluate the environmental colonisation of a national reference hospital unit, using the total aerobic colony count (ACC) and the isolated microorganisms, as assessment tools.

Methods

A cross-sectional study was conducted in the Paediatric Intensive Care Unit (PICU) of the Hospital Central de Maputo during a four-week period in 2018. Surfaces and air were sampled before and after room cleaning, using swabs and passive air method. Those samples were processed at the microbiology laboratory where total ACC levels were evaluated, and microorganisms were isolated, identified and assessed for antibiotic susceptibility.

Discussion

Comparison of the total median ACC of the indoor air (287 cfu/m³ before and 195 cfu/m³ after) and surfaces (0.38 cfu/cm² before and 0.33 cfu/cm² after) before and after room cleaning did not show significant differences (P>0.05). Microorganisms of epidemiological importance, including coagulase negative staphylococci (CoNS), Klebsiella pneumoniae and Serratia odorifera were isolated and all of these three were multi-drug resistant (MDR).

Conclusion

The results showed controlled contamination levels on high touch surfaces in the patient environment and a high level of contamination of the indoor air suggesting deficiencies in the PICU environmental decontamination process. There was evidence of the presence of fungi and MDR species of epidemiological importance in the context of HCAI.

The antibacterial potency and antibacterial mechanism of a commercially available surface-anchoring quaternary ammonium salt (SAQAS)-based biocide in vitro

AIMS

To determine the antimicrobial potency of a surface-anchored quaternary ammonium salt (SAQAS)-based biocide during in vitro wet and dry fomite assays and to determine the mechanism of killing bacteria on the surface.

METHODS AND RESULTS

Wet and dry fomite assays were established in vitro for a commercially available biocide (SAQAS-A) applied to glass and low-density polyethylene (LDPE) surfaces. Both wet and dry fomite tests showed the active killing of Gram-positive and Gram-negative bacteria but not endospores. Assays measuring membrane permeability (ATP and DNA release), bacterial membrane potential and bacterial ROS production were correlated with the time-to-kill profiles to show SAQAS-A activity in suspension and applied to a surface.

CONCLUSIONS

SAQAS-A is an effective biocide against model strains of vegetative bacteria. The killing mechanism for SAQAS-A observed minimal membrane depolarization, a surge in ROS production and assessment of membrane permeability supported the puncture of cells in both suspension and surface attachment, leading to cell death.

SIGNIFICANCE AND IMPACT OF THE STUDY

SAQAS represents effective surface biocides against single challenges with bacteria through a mechanical killing ability that supports real-world application if their durability can be demonstrated to maintain residual activity.

The Evaluation of Electrolyzed Water, Sodium Dichloroisocyanurate and Peracetic Acid with Hydrogen Peroxide for the Disinfection of Patient Room Surfaces

BACKGROUND

Sporicidal disinfectants are necessary to control Clostridioides difficile and Candida auris. Novel application methods such as electrostatic sprayers may increase disinfection effectiveness. We employed a standardized protocol to assess three sporicidal disinfectants: electrolyzed water (EW), sodium dichloroisocyanurate (NaDCC) and peracetic acid/hydrogen peroxide (PAA/H₂O₂).

METHODS

The study was conducted at two New York City hospitals (1,082 total beds) over an 18-month period. The three chemicals were applied by housekeeping personnel following the hospital protocol; the use of electrostatic sprayers was incorporated into EW and NaDCC. In randomly selected rooms, five surfaces were sampled for microbial colony counts after cleaning. Data analyses were performed using negative binomial logistic regression.

RESULTS

We collected 774 samples. NaDCC-disinfected surfaces had a lower mean colony count (14 CFU) compared to PAA/H₂O₂ (18 CFU, p=0.36) and EW (37 CFU, p<.001). PAA/H₂O₂ and EW had more samples with any growth (both p<.05) compared to NaDCC. NaDCC applied with wipes and an electrostatic sprayer had the lowest number of samples with no growth and <2.5 CFU/cm² (difference not significant).

CONCLUSIONS

The use of NaDCC for surface disinfection resulted in the lowest bacterial colony counts on patient room high touch surfaces in our study.

Survey on the current status of the indication and implementation protocols for bile replacement in patients with external biliary drainage with special reference to infection control

PURPOSE

This survey of bile replacement (BR) was conducted on patients with external biliary drainage to assess the current status of indication and implementation protocol of BR with special reference to infection control.

METHODS

A 12-item questionnaire regarding the performance of perioperative BR was sent to 124 institutions in Japan.

RESULTS

BR was performed in 29 institutions, and the indication protocol was introduced in 19. BR was performed preoperatively in 11 institutions, pre- and postoperatively in 12, and postoperatively in 6. The methods used for BR administration included oral intake (n = 10), nasogastric tube (n = 1), enteral nutrition tube (n = 3), oral intake and enteral nutrition tube (n = 6), oral intake or nasogastric tube (n = 2), nasogastric tube and enteral nutrition tube (n = 2), and oral intake or nasogastric tube and enteral nutrition tube (n = 5). In 10 of 29 institutions, isolation of multidrug-resistant organisms and a high bacterial load were considered contraindications for the use of BR. Seven institutions experienced environmental contamination.

CONCLUSIONS

Given the different implementation of BR among institutions, the appropriate indication and protocols for BR should be established for infection control.

Prevalence and Antimicrobial Resistance of Paeniclostridium sordellii in Hospital Settings

(1) Background: The purpose of this study was to determine the prevalence of clostridia strains in a hospital environment in Algeria and to evaluate their antimicrobial susceptibility to antibiotics and biocides. (2) Methods: Five hundred surface samples were collected from surfaces in the intensive care unit and surgical wards in the University Hospital of Tlemcen, Algeria. Bacterial identification was carried out using MALDI-TOF-MS, and then the minimum inhibitory concentrations (MICs) of various antimicrobial agents were determined by the E-test method. P. sordellii toxins were searched by enzymatic and PCR assays. Seven products intended for daily disinfection in the hospitals were tested against Clostridium spp. spore collections. (3) Results: Among 100 isolates, 90 P. sordellii were identified, and all strains were devoid of lethal and hemorrhagic toxin genes. Beta-lactam, linezolid, vancomycin, tigecycline, rifampicin, and chloramphenicol all proved effective against isolated strains. Among all strains tested, the spores of P. sordellii exhibited remarkable resistance to the tested biocides compared to other Clostridium species. The (chlorine-based 0.6%, 30 min), (glutaraldehyde solution 2.5%, 30 min), and (hydrogen peroxide/peracetic acid 3%, 15 min) products achieved the required reduction in spores. (4) Conclusions: Our hospital’s current cleaning and disinfection methods need to be optimized to effectively remove spores from caregivers’ hands, equipment, and surfaces.

Bacterial colonization dynamics and antibiotic resistance gene dissemination in the hospital environment after first patient occupancy: a longitudinal metagenetic study

BACKGROUND

Humans spend the bulk of their time in indoor environments. This space is shared with an indoor ecosystem of microorganisms, which are in continuous exchange with the human inhabitants. In the particular case of hospitals, the environmental microorganisms may influence patient recovery and outcome. An understanding of the bacterial community structure in the hospital environment is pivotal for the prevention of hospital-acquired infections and the dissemination of antibiotic resistance genes. In this study, we performed a longitudinal metagenetic approach in a newly opened ward at the Charité Hospital (Berlin) to characterize the dynamics of the bacterial colonization process in the hospital environment after first patient occupancy.

RESULTS

The sequencing data showed a site-specific taxonomic succession, which led to stable community structures after only a few weeks. This data was further supported by network analysis and beta-diversity metrics. Furthermore, the fast colonization process was characterized by a significant increase of the bacterial biomass and its alpha-diversity. The compositional dynamics could be linked to the exchange with the patient microbiota. Over a time course of 30 weeks, we did not detect a rise of pathogenic bacteria in the hospital environment, but a significant increase of antibiotic resistance determinants on the hospital floor.

CONCLUSIONS

The results presented in this study provide new insights into different aspects of the environmental microbiome in the clinical setting, and will help to adopt infection control strategies in hospitals and health care-related buildings. Video Abstract.

Ten Thousand-Fold Higher than Acceptable Bacterial Loads Detected in Kenyan Hospital Environments: Targeted Approaches to Reduce Contamination Levels

Microbial monitoring of hospital surfaces can help identify target areas for improved infection prevention and control (IPCs). This study aimed to determine the levels and variations in the bacterial contamination of high-touch surfaces in five Kenyan hospitals and identify the contributing modifiable risk factors. A total of 559 high-touch surfaces in four departments identified as high risk of hospital-acquired infections were sampled and examined for bacterial levels of contamination using standard bacteriological culture methods. Bacteria were detected in 536/559 (95.9%) surfaces. The median bacterial load on all sampled surfaces was 6.0 × 10⁴ CFU/cm² (interquartile range (IQR); 8.0 × 10³–1.0 × 10⁶). Only 55/559 (9.8%) of the sampled surfaces had acceptable bacterial loads, <5 CFU/cm². Cleaning practices, such as daily washing of patient sheets, incident rate ratio (IRR) = 0.10 [95% CI: 0.04–0.24], providing hand wash stations, IRR = 0.25 [95% CI: 0.02–0.30], having running water, IRR = 0.19 [95% CI: 0.08–0.47] and soap for handwashing IRR = 0.21 [95% CI: 0.12–0.39] each significantly lowered bacterial loads. Transporting dirty linen in a designated container, IRR = 72.11 [95% CI: 20.22–257.14], increased bacterial loads. The study hospitals can best reduce the bacterial loads by improving waste-handling protocols, cleaning high-touch surfaces five times a day and providing soap at the handwash stations.

Aptasensor for the detection of Methicillin resistant Staphylococcus aureus on contaminated surfaces

There is mounting evidence that contaminated hospital environment plays a crucial role in the transmission of nosocomial pathogens such as MRSA. The institution of infection control protocols is predicated on the early laboratory detection of the pathogen from relevant samples. Processing of environmental samples for the presence of bacterial contaminants in the clinical environment is poorly standardized when compared with analysis of clinical samples. The various laboratory methods available for processing environmental samples are difficult to standardized and most require a long turnaround time before results are available. In this study, we present a report of the performance of a novel pathogen aptasensor swab designed to qualitatively and quantitatively detect MRSA, on contaminated non-absorbable surfaces. The visual detection limit of the MRSA aptasensor swab was less than 100 CFU/ml and theoretically using a standard curve, was 2 CFU/ml. A relatively short turnaround time of 5 min was established for the assay while the linear range of quantitation was 10²-10⁵ CFU/ml. Engineered aptasensor targets MRSA selectively and binds to none of the other tested bacterial pathogen, on a multi-contaminated surface. This novel detection tool was easy to use and relatively cheap to produce.

Efficacy of Three Commercial Disinfectants in Reducing Microbial Surfaces' Contaminations of Pharmaceuticals Hospital Facilities

To evaluate and validate the efficacy of disinfectants used in our cleaning procedure, in order to reduce pharmaceutical hospital surfaces' contaminations, we tested the action of three commercial disinfectants on small representative samples of the surfaces present in our hospital cleanrooms. These samples (or coupons) were contaminated with selected microorganisms for the validation of the disinfectants. The coupons were sampled before and after disinfection and the microbial load was assessed to calculate the Log₁₀ reduction index. Subsequently, we developed and validated a disinfection procedure on real surfaces inside the cleanrooms intentionally contaminated with microorganisms, using approximately 10⁷-10⁸ total colony forming units per coupon. Our results showed a bactericidal, fungicidal, and sporicidal efficacy coherent to the acceptance criteria suggested by United States Pharmacopeia 35 <1072>. The correct implementation of our cleaning and disinfection procedure, respecting stipulated concentrations and contact times, led to a reduction of at least 6 Log₁₀ for all microorganisms used. The proposed disinfection procedure reduced the pharmaceutical hospital surfaces' contaminations, limited the propagation of microorganisms in points adjacent to the disinfected area, and ensured high disinfection and safety levels for operators, patients, and treated surfaces.

Evaluation of Antibacterial Activity of Three Quaternary Ammonium Disinfectants on Different Germs Isolated from the Hospital Environment

BACKGROUND

The microbiological risk of the hospital environment, including inert surfaces, medical devices, and equipment, represents a real problem.

OBJECTIVE

This study is aimed at demonstrating and assessing the antibacterial activity of three synthetic disinfectants classified as quaternary ammoniums on different bacterial strains (Gram-negative and Gram-positive like Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus) isolated from the hospital environment. The reference strains included Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853 used as negative control strains.

METHOD

Three quaternary ammonium disinfectants were tested: DDN9® (0.5%) which contains didecylmethylpolyoxyethylammonium propionate as an active substance, spray (0.4%) containing quaternary ammonium compounds, and Phagosurf ND® (0.4%) with didecyldimethylammonium chloride. Their effect was evaluated using the disk diffusion technique and the broth dilution methods, allowing the Minimum Inhibitory Concentration (MIC) and then the Minimum Bactericidal Concentration (MBC).

RESULT

Only the growth of Gram-positive bacteria and some strains of Gram-negative bacteria were inhibited by the three synthetic disinfectants. NDD9® demonstrated an antibacterial effect only against the Gram-positive strains (S. aureus and S. aureus ATCC 29213) with a MIC of 0.25 mg/ml. The disinfectant spray showed effect against all four strains including E. coli (9), S. aureus, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 with an inhibitory concentration of 4 mg/ml, while the growth of S. aureus ATCC 29213 was inhibited at 2 mg/ml. The third disinfectant, Phagosurf ND®, inhibited only the growth of S. aureus ATCC 29213 at a MIC of 4 mg/ml.

CONCLUSION

This study is the first here in Morocco to evaluate the bacterial activity of products intended for the control of the healthcare environment. The results obtained on the three disinfectants tested reveal an ineffectiveness against some isolated strains from the hospital environment.

Comparing intervention strategies for reducing Clostridioides difficile transmission in acute healthcare settings: an agent-based modeling study

Background

Clostridioides difficile infection (CDI) is one of the most common healthcare infections. Common strategies aiming at controlling CDI include antibiotic stewardship, environmental decontamination, and improved hand hygiene and contact precautions. Mathematical models provide a framework to evaluate control strategies. Our objective is to evaluate the effectiveness of control strategies in decreasing C. difficile colonization and infection using an agent-based model in an acute healthcare setting.

Methods

We developed an agent-based model that simulates the transmission of C. difficile in medical wards. This model explicitly incorporates healthcare workers (HCWs) as vectors of transmission, tracks individual patient antibiotic histories, incorporates varying risk levels of antibiotics with respect to CDI susceptibility, and tracks contamination levels of ward rooms by C. difficile. Interventions include two forms of antimicrobial stewardship, increased environmental decontamination through room cleaning, improved HCW compliance, and a preliminary assessment of vaccination.

Results

Increased HCW compliance with CDI patients was ranked as the most effective intervention in decreasing colonizations, with reductions up to 56%. Antibiotic stewardship practices were highly ranked after contact precaution compliance. Vaccination and reduction of high-risk antibiotics were the most effective intervention in decreasing CDI. Vaccination reduced CDI cases to up to 90%, and the reduction of high-risk antibiotics decreased CDI cases up to 23%.

Conclusions

Overall, interventions that decrease patient susceptibility to colonization by C. difficile, such as antibiotic stewardship, were the most effective interventions in reducing both colonizations and CDI cases.

High levels of toxigenic Clostridioides difficile contamination of hospital environments: a hidden threat in hospital-acquired infections in Kenya

Introduction

The contribution of Clostridioides difficile (formerly Clostridium difficile) to the burden of hospital-associated infections (HAIs) remains undetermined in many African countries.

Aim

This study aimed to identify a sensitive and readily adaptable C. difficile detection assay and to evaluate the C. difficile HAI risk in Kenya.

Methodology

Sterile swabs in neutralizing buffer were used to sample equipment or surfaces that patients and clinical staff touched frequently. These swabs were either plated directly on chromogenic agar or cultured in an enrichment broth before plating. The swab suspensions, enrichment broth and plate cultures were screened by quantitative PCR (qPCR) to determine the most efficient detection method. The HAI risk was evaluated by testing the C. difficile-positive samples by qPCR for the A, B and binary toxins.

Results

C. difficile was detected on 4/57 (7.0 %) equipment and surfaces by direct culture. The additional enrichment step increased the detection rate 10-fold to 43/57 (75.4 %). In total, 51/57 (89.5 %) environmental samples were positive for C. difficile detected through either culture or qPCR. The genes encoding the primary toxins, tcdA and tcdB, were detected on six surfaces, while the genes encoding the binary toxins, cdtA and cdtB, were detected on 2/57 (3.5 %) and 3/57 (5.3 %) surfaces, respectively. Different C. difficile toxin gene profiles were detected: the tcdA+/tcdB− gene profile on 4/10 (40 %) high-touch surfaces, tcdA−/tcdB+ on 3/10 (30 %) surfaces, tcdA+/tcdB+/cdtA+/cdtB+ on 2/10 (20 %) surfaces and tcdA−/tcdB+/cdtB+ on one high-touch surface.

Conclusion

The widespread contamination of hospital environments by toxigenic C. difficile gives a strong indication of the high risk of C. difficile infections (CDIs). The two-step culture process described can easily be adapted for monitoring hospital environment contamination by C. difficile.

Microbial contamination and efficacy of disinfection procedures of companion robots in care homes

Background

Paro and other robot animals can improve wellbeing for older adults and people with dementia, through reducing depression, agitation and medication use. However, nursing and care staff we contacted expressed infection control concerns. Little related research has been published. We assessed (i) how microbiologically contaminated robot animals become during use by older people within a care home and (ii) efficacy of a cleaning procedure.

Methods

This study had two stages. In stage one we assessed microbial load on eight robot animals after interaction with four care home residents, and again following cleaning by a researcher. Robot animals provided a range of shell-types, including fur, soft plastic, and solid plastic. Stage two involved a similar process with two robot animals, but a care staff member conducted cleaning. The cleaning process involved spraying with anti-bacterial product, brushing fur-type shells, followed by vigorous top-to-tail cleaning with anti-bacterial wipes on all shell types. Two samples were taken from each of eight robots in stage one and two robots in stage two (20 samples total). Samples were collected using contact plate stamping and evaluated using aerobic colony count and identification (gram stain, colony morphology, coagulase agglutination). Colony counts were measured by colony forming units per square centimetre (CFU/cm²).

Results

Most robots acquired microbial loads well above an acceptable threshold of 2.5 CFU/cm² following use. The bacteria identified were micrococcus species, coagulase negative staphylococcus, diptheriods, aerobic spore bearers, and staphylococcus aureus, all of which carry risk for human health. For all devices the CFU/cm² reduced to well within accepted limits following cleaning by both researcher and care staff member.

Conclusions

Companion robots will acquire significant levels of bacteria during normal use. The simple cleaning procedure detailed in this study reduced microbial load to acceptable levels in controlled experiments. Further work is needed in the field and to check the impact on the transmission of viruses.

Cleaning and disinfection of crates and trucks used for duck transport: field observations during the H5N8 avian influenza outbreaks in France in 2017

Transport of infected birds is thought to play a key role in the spread of avian influenza (AI) on poultry farms during epizootic outbreaks. Ensuring efficient cleaning and disinfection (C&D) of equipment used for transport is needed to prevent the spread of AI. This study aimed to evaluate the efficacy against the AI virus of C&D protocols applied on trucks and crates used for the transport of ducks during the H5N8 AI outbreaks in France in 2017. In 3 abattoirs, 16 transport vehicles and their crates were sampled by swabbing to detect the influenza type A genome by real-time reverse-transcription polymerase chain reaction. Vehicles were tested before and after decontamination, which was carried out in accordance with the abattoirs' protocols. A total of 86 samples out of 299 collected before C&D were positive for AI (29%); 7 trucks out of 16 transported crates detected positive for AI. After C&D, the AI genome was detected in 56 samples out of 308 (18%). Ten trucks were loaded with a shipment of AI-positive crates. Eight vehicles were detected positive in the cabin, on the truck bed, and/or on the wheels. Despite reinforcement of C&D, the efficacy of decontamination was variable among slaughterhouses. The efficacy seemed to depend on the initial contamination load, C&D protocols, and how the protocol is implemented. Breaks in biosecurity measures led to frequent contamination of trucks after C&D. Observational studies during animal health crises are of interest to analyze practices in emergency conditions and to put forward measures aimed at increased preparedness.

Infectious Risk of the Hospital Environment in the Center of Morocco: A Case of Care Unit Surfaces

BACKGROUND

Equipment and hospital surfaces constitute a microbial reservoir that can contaminate hospital users and thus create an infectious risk. The aim of this work, which was carried out for the first time at a hospital in Meknes (regional hospital in the center of Morocco), is to evaluate the microbiological quality of surfaces and equipment in three potential risk areas (burn unit, operating room, and sterilization service).

METHODS

This study was carried out over a period of 4 months (February-May 2017). A total of 60 samples were taken by swabbing according to the standard (ISO/DIS 14698-1 (2004)) in an environment of dry area and equipment after biocleaning. Isolation and identification were performed according to conventional bacteriological methods and by microscopic observation for fungi.

RESULTS

The study showed that 40% of surface samples were contaminated after biocleaning. The burn unit recorded a percentage of 70% contamination (p value <0.001), 13% for the sterilization service, and 7% for the operating room. 89% of the isolates were identified as Gram-positive bacteria against 11% for fungi (p value <0.001). Bacterial identification showed coagulase-negative staphylococci (32%), Bacillus spp. (16%), Corynebacterium (8%), and oxidase-negative Gram-positive bacillus (40%) while fungal identification showed Aspergillus niger (n = 2) and Aspergillus nidulans (n = 1).

CONCLUSION

To control the infectious risk related to equipment and hospital surfaces, it would be necessary to evaluate the disinfection protocol applied in these units.

Effect of thermal control of dry fomites on regulating the survival of human pathogenic bacteria responsible for nosocomial infections

We monitored the survival of human pathogenic bacteria [Escherichia coli (ATCC), extended-spectrum β-lactamase-producing E. coli (Clinical isolate), New Delhi metallo-β-lactamase-producing E. coli (clinical isolate), Staphylococcus aureus (ATCC)] on dry materials (vinyl chloride, aluminum, plastic, stainless steel) at distinct temperatures (room temperature or 15°C–37°C). These bacteria favored a lower temperature for their prolonged survival on the dry fomites, regardless of the material type. Interestingly, when mixed with S. aureus, E. coli survived for a longer time at a lower temperature. Cardiolipin, which can promote the survival of S. aureus in harsh environments, had no effect on maintaining the survival of E. coli. Although the trends remained unchanged, adjusting the humidity from 40% to 60% affected the survival of bacteria on dry surfaces. Scanning electron microscopic analysis revealed no morphological differences in these bacteria immediately before or after one day of dry conditions. In addition, ATP assessment, a method used to visualize high-touch surfaces in hospitals, was not effective at monitoring bacterial dynamics. A specialized handrail device fitted with a heater, which was maintained at normal human body core temperature, successfully prohibited the prolonged survival of bacteria [Enterococcus faecalis (ATCC), E. coli (ATCC), Pseudomonas aeruginosa (ATCC), S. aureus (ATCC), Acinetobacter baumannii (clinical isolate), and Serratia marcescens (clinical isolate)], with the exception of spore-forming Bacillus subtilis (from our laboratory collection) and the yeast-like fungus Candida albicans (from our laboratory collection)] on dry surfaces. Taken together, we concluded that the tested bacteria favor lower temperatures for their survival in dry environments. Therefore, the thermal control of dry fomites has the potential to control bacterial survival on high-touch surfaces in hospitals.

Evaluation of antibiotic susceptibility patterns of pathogens isolated from routine laboratory specimens at Ndola Teaching Hospital: A retrospective study

Periodic monitoring of antibiotic susceptibility patterns in clinical settings is vital to ascertain the potency as well as re-establishing empirical therapy. This retrospective study aimed to evaluate the antibiotic susceptibility patterns of pathogens isolated from routine laboratory specimens at Ndola Teaching Hospital. A retrospective study was conducted on routine specimens received between May 2016 and July 2018. Specimens were cultured on standard media and Kirby-Bauer disc diffusion method was used for susceptibility testing in accordance with the Clinical and Laboratory Standard Institute's recommendations. A total of 693 specimens were analyzed, of which 65.9% (457) specimens came from inpatient departments and 49.1% (340) came from female patients. The commonest specimens were urine (58.6%), blood (12.7%) and wound swabs (8.5%), and the most common microorganisms were coliform (29.3%), Staphylococcus aureus (15.4%), coagulase negative Staphylococci (CoNS, 13.4%), and Escherichia coli (13%). The highest percentage of resistance to any particular antibiotic was co-trimoxazole (91.7%, 33) followed by nalidixic acid (75.2%, 279), norfloxacin (69.0%, 100), ceftazidime (55.7%, 185), nitrofurantoin (46.6%, 191), chloramphenicol (43%, 111) and ciprofloxacin (8.6%, 271). Furthermore, patient location had resistance effect on coliform (p = 0.014), CoNS (p = 0.031), Streptococcus species (p = 0.024) and Klebsiella species (p = 0.004) to nitrofurantoin, ceftazidime, nitrofurantoin and chloramphenicol, respectively. Besides coliform, resistance of Enterobacter species to ceftazidime and Proteus species to nalidixic acid were more from female patients. Generally, the most effective antibiotics were chloramphenicol and nitrofurantoin with addition of ceftazidime on blood pathogens and ciprofloxacin on wound swab pathogens. The common isolates were coliform, S. aureus, coagulase negative Staphylococci and Escherichia coli. The resistance of most bacteria to ceftazidime and nitrofurantoin were influenced by both gender and location. Our study presents a broad overview of the resistance profiles of bacterial isolates. However, more nosocomial prevalence and antibiogram studies on individual routine specimens are required to provide a more detailed picture of resistance patterns.

Microbiological evaluation of environmental cleanliness in haematopoietic cell transplant patient rooms: implementing JACIE standards

BACKGROUND

Environmental hygiene is one of the most important strategies to prevent hospital-acquired infections by reducing pathogens in haematopoietic cell transplant (HCT) patient rooms. This study was designed in response to JACIE requirements for microbiological monitoring, and aimed to assess environmental hygiene in protective isolation rooms.

METHODS

Environmental cleanliness was assessed by measuring microbial loads in at-rest and operational conditions sampled from target surfaces, and in passive and active air from rooms occupied by patients with different grades of neutropenia. The study also evaluated whether microbial loads were influenced by isolation precautions.

RESULTS

The failure rate of cleanliness on target surfaces in at-rest conditions was 0% compared with 37% for surfaces and 13% for passive and active air samples in operational conditions. Differences in failure rates were observed in the rooms of patients with different levels of neutropenia (P=0.036 for surfaces, 0.028% for passive air). No relationship was found between infections and microbial loads.

CONCLUSIONS

Microbiological assessment integrated with an enhanced monitoring programme for hospital hygiene provides invaluable information to drive infection control policies in HCT patients. These results highlight the need to set and validate strict standards for the assessment of cleanliness in a clinical setting.

Bacteriological Monitoring of Inanimate Surfaces and Equipment in Some Referral Hospitals in Assiut City, Egypt

Hospital-acquired infections represent a serious public health problem in all countries. It is clear that monitoring of the hospital environment is an essential element in the control and a part of the policy for preventing nosocomial infections. It allows a better understanding of the microbial ecology for the purpose of conducting preventive and corrective actions. The aims of this work were to determine the percentage of bacterial contamination of environmental samples and to identify potential nosocomial pathogens isolated from environments of seven referral hospitals from 2009 to 2015. By using the swab technique, 12863 samples were collected. Qualitative and quantitative cultures were performed. The organisms were primarily identified by colony morphology, microscopy of Gram stain, and standard biochemical tests. 25.6% of total samples showed contamination (93% was monomicrobial and 7.0% was polymicrobial). The predominant species was coagulase-negative staphylococcus (CNS) (32%), followed by methicillin-resistant S. aureus (MRSA) (26%) and then K. pneumonia (10.6%). The percentage of contamination varied among the covered hospitals and according to the year of monitoring with highly statistically significant difference (p value < 0.001). Direct contact with environmental surfaces or equipment transmits the majority of nosocomial infection. Major nosocomial pathogens have been identified. Hospital managers and healthcare bodies must be aware of the reality of the concept of environmental bacterial tanks and the need for respect of biocleaning procedures and choice of biocleaning tools.

Methods for quantification of growth and productivity in anaerobic microbiology and biotechnology

Anaerobic microorganisms (anaerobes) possess a fascinating metabolic versatility. This characteristic makes anaerobes interesting candidates for physiological studies and utilizable as microbial cell factories. To investigate the physiological characteristics of an anaerobic microbial population, yield, productivity, specific growth rate, biomass production, substrate uptake, and product formation are regarded as essential variables. The determination of those variables in distinct cultivation systems may be achieved by using different techniques for sampling, measuring of growth, substrate uptake, and product formation kinetics. In this review, a comprehensive overview of methods is presented, and the applicability is discussed in the frame of anaerobic microbiology and biotechnology.

Healthcare-associated infections: bacteriological characterization of the hospital surfaces in the University Hospital of Abomey-Calavi/so-ava in South Benin (West Africa)

Background

Healthcare-associated infections have become a public health problem, creating a new burden on medical care in hospitals. The emergence of multidrug-resistant bacteria poses a difficult task for physicians, who have limited therapeutic options. The dissemination of pathogens depends on “reservoirs”, the different transmission pathways of the infectious agents and the factors favouring them. Contaminated environmental surfaces are an important potential reservoir for the transmission of many healthcare-associated pathogens. Pathogens can survive or persist in the environment for months and be a source of infection transmission when appropriate hygiene and disinfection procedures are inefficient. The aim of this study was to identify bacterial species from hospital surfaces in order to effectively prevent healthcare-associated infections.

Methods

Samples were taken from surfaces at the University Hospital of Abomey-Calavi/So-Ava in South Benin (West Africa). To achieve the objective of this study, 160 swab samples of hospital surfaces were taken as recommended by the International Organization for Standardization (ISO 14698-1). These samples were analysed in the bacteriology section of the National Laboratory for Biomedical Analysis. All statistical analyses were performed using SPSS Statistics 21 software. A Chi Square Test was used to test the association between the Results of culture samples and different care units.

Results

Of the 160 surface samples, 65% were positive for bacteria. The frequency of isolation was predominant in Paediatrics (87.5%). The positive samples were 64.2% Gram-positive bacteria and 35.8% of Gram-negative bacteria. Staphylococcus aureus predominated (27.3%), followed by Bacillus spp. (23.3%).

The proportion of other microorganisms was negligible. S. aureus and Staphylococcus spp. were present in all care units. There was a statistically significant association between the Results of culture samples and different care units (χ2 = 12.732; p = 0.048).

Conclusion

The bacteria found on the surfaces of the University Hospital of Abomey-Calavi/So-Ava’s care environment suggest a risk of healthcare-associated infections. Adequate hospital hygiene measures are required. Patient safety in this environment must become a training priority for all caregivers.

Molecular identification and genotyping of Acinetobacter baumannii isolated from burn patients by PCR and ERIC-PCR

BACKGROUND

Acinetobacter baumannii is one of the most important agents of hospital infections. Rapid and accurate identification and genotyping of A. baumannii is very important, especially in burn hospitals in order to prevent the spread of related nosocomial infections and to further epidemiological studies.

MATERIAL AND METHODS

For two months, 82 A. baumannii isolates were collected from burn wound swabs of patients in a major burn hospital in Tehran. A. baumannii isolates were identified by conventional microbiological test and polymerase chain reaction (PCR) using the primers of blaOXA-51 gene, while the genetic linkage of A. baumannii isolates was investigated by enterobacterial repetitive intragenic consensus (ERIC)-PCR technique. Similarity, a cut-off of ⩾ 95% was considered for classifying the genotypes.

RESULTS

The molecular test (PCR) confirmed 97.56% of phenotypic results for the detection of A. baumannii isolates. ERIC-PCR results revealed 14 different ERIC patterns (ERIC-types) including 11 common types and three unique types.

CONCLUSION

Our findings show that we can simply and quickly detect A. baumannii isolates by PCR using blaOXA genes and genetic diversity by ERIC-PCR, respectively. These rapid and simple techniques for the routine screening and identification of clinical A. baumannii isolates could be useful with epidemic potential.

Study of the Effectiveness of Multipurpose Solutions on the Bacterial Disinfection of Silicone Hydrogel Contact Lenses In Vitro

OBJECTIVES

To assess the antimicrobial effectiveness of multipurpose solutions in regard to the disinfection of silicone hydrogel contact lenses (CL) using a study of clinical bacterial isolates from ocular material.

METHODS

Three multipurpose solutions (solution A: polyhexamethylene biguanide 0.00025 g/100 mL; solution B: polyquaternary-1 0.001% and myristamidopropyl dimethylamine 0.0006%; and solution C: polyaminopropyl biguanide 0.00013% and polyquaternary 0.0001%) were used as a 3-phase disinfection on silicone hydrogel CL contaminated with bacteria from clinical isolates that were divided into five groups (group 1: Pseudomonas aeruginosa; group 2: Staphylococcus aureus; group 3: Staphylococcus epidermidis; group 4: Streptococcus spp; and group 5: enterobacteria).

RESULTS

No differences were observed between the 24- and 48-hr measurements in any of the samples, and the positivity of microorganisms in T0 was 100% for all solutions; it was 0% in T3. Therefore, only steps T1 (rubbing followed by rinsing) and T2 (rubbing followed by rinsing and immersion of CL into solution) were considered for analysis at the 24-hr measurement time. Throughout the phases, a decrease in the number of bacteria was observed, culminating in the elimination (no recovery) of all microorganisms in the three solutions.

CONCLUSIONS

At the end of the proposed process, the tested solutions were effective.

Transmission of Staphylococcus aureus from dry surface biofilm (DSB) via different types of gloves

Background

Pathogens can survive for extended periods when incorporated into biofilm on dry hospital surfaces (ie, dry-surface biofilm, DSB). Bacteria within biofilm are protected from desiccation and have increased tolerance to cleaning agents and disinfectants.

Objective

We hypothesized that gloved hands of healthcare personnel (HCP) become contaminated with DSB bacteria and hence may transmit bacteria associated with healthcare-associated infections (HAIs).

Method

Staphylococcus aureus DSB was grown in vitro on coupons in a bioreactor over 12 days with periodic nutrition interspersed with long periods of dehydration. Each coupon had ~107 DSB bacterial cells. Transmission was tested with nitrile, latex, and surgical gloves by gripping DSB-covered coupons then pressing finger tips onto a sterile horse blood agar surface for up to 19 consecutive touches and counting the number of colony-forming units (CFU) transferred. Coupons were immersed in 5% neutral detergent to simulate cleaning, and the experiment was repeated.

Results

Bacterial cells were readily transmitted by all 3 types of gloves commonly used by HCP. Surprisingly, sufficient S. aureus to cause infection were transferred from 1 DSB touch up to 19 consecutive touches. Also, 6 times more bacteria were transferred by nitrile and surgical gloves than to latex gloves (P <.001). Treating the DSB with 5% neutral detergent increased the transmission rate of DSB bacteria 10-fold.

Conclusion

Staphylococcus aureus incorporated into environmental DSB and covered by extracellular polymeric substances readily contaminates gloved hands and can be transferred to another surface. These results confirm the possibility that DSB contributes to HAI acquisition.

Comparison of nylon-flocked swab and cellulose sponge methods for carbapenem-resistant Enterobacteriaceae and gram-negative organism recovery from high-touch surfaces in patient rooms

The ideal sampling method and benefit of qualitative versus quantitative culture for carbapenem-resistant Enterobacteriaceae (CRE) recovery in hospitalized patient rooms and bathrooms is unknown. Although the use of nylon-flocked swabs improved overall gram-negative organism recovery compared with cellulose sponges, they were similar for CRE recovery. Quantitative culture was inferior and unrevealing beyond the qualitative results.

Outbreak report: a nosocomial outbreak of vancomycin resistant enterococci in a solid organ transplant unit

Background

Vancomycin resistant enterococci (VRE) are an emerging problem in health care settings. The purpose of the investigation was to assess the extent of the outbreak including environmental contamination and to limit further transmission.

Methods

We used retrospective patient and laboratory data including pulse field gel electrophoresis (PFGE) typing and virulence and resistance gene analysis. For comparison of medians the Mann-Whitney and for comparison of proportions the Fisher exact tests were used.

Results

PFGE typing of VRE strains of an outbreak of 15 VRE cases in a solid transplant unit revealed that nine of the cases belonged to one identical pattern (A), which was only found twice in the environment. Eleven further positive environmental samples showed a different, but identical PFGE pattern E. Only one patient was infected with this environmental strain.

Two of nine (22.2%) PFGE A, but nine of eleven (81.2%) PFGE E samples were positive for gelatinase E (p = 0.01), which is described as enhancing biofilm production, suggesting a survival benefit for this strain on inanimate surfaces.

Conclusion

Routine disinfection was not able to stop the cluster, but after repeated enforcement of the infection prevention and control (IPC) bundle such as training, strict adherence to hand hygiene and surface disinfection no further cases were observed. We conclude that certain VRE strains predominate in the environment whereas others predominate in humans. Enforcement of the IPC bundle is essential for controlling VRE outbreaks and reducing further transmission.

Long-term metabolic persistence of gram-positive bacteria on health care-relevant plastic

BACKGROUND

Health care-associated opportunistic pathogens Staphylococcus aureus and Enterococcus faecium persist on dry environments and can contribute to organism transmission through contact. These organisms can be monitored on surfaces by culture, molecular methods, or metabolic assays. This study was designed to determine the kinetics of bacterial persistence on acrylonitrile butadiene styrene, a plastic commonly used in the manufacture of bedrails.

MATERIALS AND METHODS

Polymerase chain reaction for genomic DNA was used to confirm the presence of bacteria cells on this plastic irrespective of viability. Bacterial viability was measured by culture, ATP quantification, and a metabolic assay at time points up to and longer than 1 year.

RESULTS

Polymerase chain reaction confirmed the presence of bacteria on the plastic for the entire time period studied. However, S aureus culturability was reduced after 3 and 7 weeks; neither organism was culturable after 1 year. At 7 weeks, ATP levels were reduced for both organisms, paralleling S aureus culturability but indicating that ATP quantification did not predict E faecium culturability. S aureus-reducing potential was reduced after 7 weeks, whereas E faecium-reducing potential reached the level of fresh inoculum after 12 hours in broth culture. Low but significant levels of metabolic activity were detected for each organism after 1 year.

CONCLUSIONS

S aureus and E faecium cells may retain viability on plastic for longer than 1 year.

Visual Detection of Multiple Nucleic Acids in a Capillary Array

Multi-target, short time, and resource-affordable methodologies for the detection of multiple nucleic acids in a single, easy to operate test are urgently needed in disease diagnosis, microbial monitoring, genetically modified organism (GMO) detection, and forensic analysis. We have previously described the platform called CALM (Capillary Array-based Loop-mediated isothermal amplification for Multiplex visual detection of nucleic acids). Herein, we describe improved fabrication and performance processes for this platform. Here, we apply a small, ready-to-use cassette assembled by capillary array for multiplex visual detection of nucleic acids. The capillary array is pre-treated into a hydrophobic and hydrophilic pattern before fixing loop-mediated isothermal amplification (LAMP) primer sets in capillaries. After assembly of the loading adaptor, LAMP reaction mixture is loaded and isolated into each capillary, due to capillary force by a single pipetting step. The LAMP reactions are performed in parallel in the capillaries. The results are visually read out by illumination with a hand-held UV flashlight. Using this platform, we demonstrate monitoring of 8 frequently appearing elements and genes in GMO samples with high specificity and sensitivity. In summary, the platform described herein is intended to facilitate the detection of multiple nucleic acids. We believe it will be widely applicable in fields where high-throughput nucleic acid analysis is required.

Effect of automated ultraviolet C-emitting device on decontamination of hospital rooms with and without real-time observation of terminal room disinfection

BACKGROUND

We studied the effectiveness of an ultraviolet C (UV-C) emitter in clinical settings and compared it with observed terminal disinfection.

METHODS

We cultured 22 hospital discharge rooms at a tertiary care academic medical center. Phase 1 (unobserved terminal disinfection) included cultures of 11 high-touch environmental surfaces (HTSs) after terminal room disinfection (AD) and after the use of a UV-C-emitting device (AUV). Phase 2 (observed terminal disinfection) included cultures before terminal room disinfection (BD), AD, and AUV. Zero-inflated Poisson regression compared mean colony forming units (CFU) between the groups. Two-sample proportion tests identified significance of the observed differences in proportions of thoroughly cleaned HTSs (CFU < 5). Significant P value was determined using the Bonferroni corrected threshold of α = .05/12 = .004.

RESULTS

We obtained 594 samples. Risk of overall contamination was 0.48 times lower in the AUV group than in the AD group (P < .001), with 1.04 log₁₀ reduction. During phase 1, overall proportion of HTSs with <5 CFUs increased in AUV versus AD by 0.12 (P = .001). During phase 2, it increased in AD versus BD by 0.45 (P < .001), with no significant difference between AD and AUV (P = .02).

CONCLUSIONS

Use of UV-C with standard cleaning significantly reduced microbial burden and improved the thoroughness of terminal disinfection. We found no further benefit to UV-C use if standard terminal disinfection was observed.

What Healthcare Workers Should Know about Environmental Bacterial Contamination in the Intensive Care Unit

Intensive care unit- (ICU-) acquired infections are a major health problem worldwide. Inanimate surfaces and equipment contamination may play a role in cross-transmission of pathogens and subsequent patient colonization or infection. Bacteria contaminate inanimate surfaces and equipment of the patient zone and healthcare area, generating a reservoir of potential pathogens, including multidrug resistant species. Traditional terminal cleaning methods have limitations. Indeed patients who receive a bed from prior patient carrying bacteria are exposed to an increased risk (odds ratio 2.13, 95% confidence intervals 1.62-2.81) of being colonized and potentially infected by the same bacterial species of the previous patient. Biofilm formation, even on dry surfaces, may play a role in reducing the efficacy of terminal cleaning procedures since it enables bacteria to survive in the environment for a long period and provides increased resistance to commonly used disinfectants. No-touch methods (e.g., UV-light, hydrogen peroxide vapour) are under investigation and further studies with patient-centred outcomes are needed, before considering them the standard of terminal cleaning in ICUs. Healthcare workers should be aware of the role of environmental contamination in the ICU and consider it in the broader perspective of infection control measures and stewardship initiatives.

Flocked nylon swabs versus RODAC plates for detection of multidrug-resistant organisms on environmental surfaces in intensive care units

To compare two culture methods [nylon fiber flocked swabs with broth enrichment versus RODAC ('replicate organism detection and counting') plates] for recovery of multidrug-resistant organisms, 780 environmental surfaces in 63 rooms of patients on contact precautions in four intensive care units at one hospital were examined. Among sites that had at least one positive culture, swab culture with broth enrichment detected the target organisms more frequently than RODAC plates (37.5% vs 26.0%, P = 0.06). There was moderate agreement between the two methods (κ = 0.44) with agreement better for small or flat surfaces compared to large or irregular surfaces.

How well does transfer of bacterial pathogens by culture swabs correlate with transfer by hands?

In laboratory testing and in isolation rooms, pickup and transfer of health care-associated pathogens by premoistened rayon swabs correlated well with pickup and transfer by bare hands or moistened gloves. These results suggest that swab cultures provide a useful surrogate indicator of the risk for pathogen pickup and transfer by hands.

DNA decontamination methods for internal quality management in clinical PCR laboratories

BACKGROUND

The polymerase chain reaction (PCR) technique, one of the most commonly applied methods in diagnostic and molecular biology, has a frustrating downside: the occurrence of false-positive signals due to contamination. In previous research, various DNA decontamination methods have been developed to overcome this limitation. Unfortunately, the use of random or poorly focused sampling methods for monitoring air and/or object surfaces leads to the incomplete elimination during decontamination procedures. We herein attempted to develop a novel DNA decontamination method (environmental surveillance, including surface and air sampling) and quality management program for clinical molecular diagnostic laboratories (or clinical PCR laboratories).

METHODS

Here, we performed a step-by-step evaluation of current DNA decontamination methods and developed an effective procedure for assessing the presence of decontaminating DNA via PCR analysis. Performing targeted environmental surveillance by sampling, which reached optimal performance over 2 weeks, and the decontamination process had been verified as reliable. Additionally, the process was validated to not affect PCR amplification efficiency based on a comparative study.

RESULTS

In this study, effective guidelines for DNA decontamination were developed. The method employed ensured that surface DNA contamination could be effectively identified and eliminated. Furthermore, our study highlighted the importance of overall quality assurance and good clinical laboratory practices for preventing contamination, which are key factors for compliance with regulatory or accreditation requirements.

CONCLUSIONS

Taken together, we provided the evidence that the presented scheme ranged from troubleshooting to the elimination of surface contamination, could serve as critical foundation for developing regular environmental surveillance guidelines for PCR laboratories.

Promising silicones modified with cationic biocides for the development of antimicrobial medical devices

We have tested silicones containing 2% or 5% of the cationic biocides polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS), 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM-BF₄) or 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF₄) against the major relevant bacterial and yeast species in health care-associated infections (HCAI). Study conducted according to the international standard ISO 22196 revealed that silicones containing 2% or 5% DMIM-BF₄ or 5% PHMG-DBS presented the highest antimicrobial activity, leading to a logarithmic growth reduction of 3.03 to 6.46 and 3.65 to 4.85 depending on the bacterial or fungal species. Heat-pretreated silicones containing 2% DMIM-BF₄ kept a high activity, with at least a 3-log reduction in bacterial growth, except against P. aeruginosa where there was only a 1.1-log reduction. After 33days, the release ratio of cationic biocide from silicone films containing 5% of DMIM-BF₄ was found to be 5.6% in pure water and 1.9% in physiological saline solution, respectively. No leaching of PHMG-DBS polymeric biocide was detected under the same conditions. These results demonstrate unambiguously that silicones containing 2% DMIM-BF₄ or 5% PHMG-DBS present high antimicrobial activity, as well as high leaching resistance and therefore may be good candidates for the development of safer medical devices.