Influence of biological fluids in bacterial viability on different hospital surfaces and fomites

Reservoirs of Nosocomial Pathogens in Intensive Care Units: A Systematic Review

Background

Nosocomial pathogens are known to exacerbate morbidity and mortality in contemporary critical healthcare. Hospital fomites, which include inanimate surfaces, have been identified as "breeding grounds" for pathogens that cause nosocomial infections. This systematic review aimed to deliver incisive insights on nosocomial pathogens in intensive care units (ICUs) and the role of fomites as potential reservoirs for their transmission.

Method

An extensive exploration of electronic databases, including PubMed and Scopus, from 1990 to 2023, was carried out between 25th and 29th May 2023, per standard PRISMA guidelines. Information were extracted from articles that reported on fomites in the ICU. Studies that did not quantitatively report the fomite contamination, and those that exclusively took samples from patients in the ICU were excluded from the analysis.

Results

About 40% of the total samples collected on fomites from all the studies yielded microbial growth, with species of Staphylococcus being the most predominant. Other prevalent microbes were Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Candida spp., Enterococcus sp., and Enterobacter sp. The neonatal intensive care unit (NICU) had the highest proportion of contaminated fomites. Among known fomites, the sphygmomanometer exhibited a 100% detection rate of nosocomial pathogens. This included E. aerogenes, Staphylococcus aureus, coagulase-negative Staphylococci (CoNS), E. coli, and K. pneumoniae. Multidrug-resistant (MDR) bacteria, such as methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococci (VRE), extended-spectrum beta-lactamase (ESBL)-producing E. coli, and MDR Pseudomonas aeruginosa were commonly isolated on fomites in the ICUs.

Conclusion

Many fomites that are readily used in patient care in the ICU harbour nosocomial pathogens. The most common fomite appeared to be mobile phones, sphygmomanometers, and stethoscopes, with Staphylococcus being the most common contaminant. Consequently, the need for rigorous disinfection and sterilization protocols on fomites in the ICU cannot be overemphasized. Additionally, heightened awareness on the subject among health professionals is crucial to mitigating the risk and burden of nosocomial infections caused by drug-resistant bacteria.

How long do nosocomial pathogens persist on inanimate surfaces? A scoping review

Healthcare hygiene plays a crucial role in the prevention of healthcare-associated infections. Patients admitted to a room where the previous occupant had a multi-drug-resistant bacterial infection are at an increased risk of colonization and infection with the same organism. A 2006 systematic review by Kramer et al. found that certain pathogens can survive for months on dry surfaces. The aim of this review is to update Kramer et al.'s previous review and provide contemporary data on the survival of pathogens relevant to the healthcare environment. We systematically searched Ovid MEDLINE, CINAHL and Scopus databases for studies that described the survival time of common nosocomial pathogens in the environment. Pathogens included in the review were bacterial, viral, and fungal. Studies were independently screened against predetermined inclusion/exclusion criteria by two researchers. Conflicts were resolved by one of two senior researchers. A spreadsheet was developed for the data extraction. The search identified 1736 studies. Following removal of duplicates and application of the search criteria, the synthesis of results from 62 included studies were included. 117 organisms were reported. The longest surviving organism reported was Klebsiella pneumoniae which was found to have persisted for 600 days. Common pathogens of concern to infection prevention and control, can survive or persist on inanimate surfaces for months. This data supports the need for a risk-based approach to cleaning and disinfection practices, accompanied by appropriate training, audit and feedback which are proven to be effective when adopted in a 'bundle' approach.

Klebsiella pneumoniae infection in cynomolgus monkeys at primate research center facility in Indonesia

BACKGROUND

Klebsiella pneumoniae infection in nonhuman primates has been widely reported and causes significant morbidity and mortality. Animal deaths occur routinely at the Primate Research Center of IPB University. The results of necropsy and culture suggested a K. pneumoniae infection.

METHODS

A mass health assessment of Cynomolgus monkeys (n = 429) was carried out by physical examination and molecular targeting K. pneumoniae (n = 96), family of Coronaviridae (n = 148) and Paramyxoviridae (n = 148).

RESULTS

A total of 49.18% of the animals had clinical symptoms of respiratory disorders, abscesses, trauma, and others. PCR results indicated that 28.57% were positive for K. pneumoniae with 35.71% mortality, while all samples were negative for both virus families.

CONCLUSIONS

There have been outbreaks caused by K. pneumoniae and/or K. pneumoniae subsp. pneumoniae. This disease is chronic, infects all of the buildings, and no tendency for disease transmission according to gender and age class.

The viability of spores is the key factor for microbial induced calcium carbonate precipitation

While previous studies mainly focused on the total number of spores as an index to predict the calcium precipitation activity (CPA) of bacterial strains, the effect of viability of spores on microbial-induced calcium precipitation (MICP) has remained highly ignored. Therefore, for the first time, we have attempted to optimize the sporulation process in terms of viable spore production and, most importantly, aimed to build a correlation between viable spores and CPA. The results have shown that for the sporulation of Bacillus sp. H4, starch and peptone are the optimal carbon and nitrogen sources, respectively. One gram per liter of sodium chloride promotes CPA and production of viable spores, whereas an increase of sodium chloride concentration beyond 8 g L^-1 significantly reduces CPA without reducing the quantity of viable spores. Exogenous conditions such as seed age, inoculation quantity, and liquid volume only pose slight influence on the sporulation and CPA. Conclusively, the spores produced under optimized conditions are more morphologically uniform and display a 20% increase in CPA compared to pre-optimized spores. Furthermore, by combining the results of heatmap analysis, it can be concluded that not only the quantity, but also the quality of viable spores is important for bacterial strain to develop high CPA and effective MICP process. This study sheds light on the breadth of biomineralization activity based on viable spores and is an imperative step toward the intelligible design of MICP-based engineering solutions. KEY POINTS: • Viability of spores is a key controlling factor in calcium precipitation activity (CPA). • Spores produced under optimized conditions display a 20% increase in CPA. • Quality of viable spores is imperative for bacterial strains to develop high CPA.

Physics of self-assembly and morpho-topological changes of Klebsiella pneumoniae in desiccating sessile droplets

HYPOTHESIS

The bacteria suspended in pure water self-assemble into unique patterns depending on bacteria-bacteria, bacteria-substrate and bacteria-liquid interactions. The physical forces acting on bacteria vary based on their respective spatial location inside the droplet cause an assorted magnitude of physical stress. The shear and dehydration induced stress on pathogens(bacteria) in drying bio-fluid droplets alters the viability and infectivity.

EXPERIMENTS

We have investigated the flow and desiccation-driven self-assembly of Klebsiella pneumoniae in the naturally evaporating sessile droplets. Klebsiella pneumoniae exhibits extensive changes in its morphology and forms unique patterns as the droplet dries, revealing hitherto unexplored rich physics governing its survival and infection strategies. Self-assembly of bacteria at the droplet contact line is characterized by order-to-disorder packing transitions with high packing densities and excessive deformations (analysed using scanning electron microscopy and atomic force microscopy). In contrast, thin-film instability-led hole formation at the center of the droplet engenders spatial packing of bacteria analogous to honeycomb weathering.

FINDINGS

Self-assembly favors the bacteria at the rim of the droplet, leading to enhanced viability and pathogenesis on the famously known "coffee ring" of the droplet compared to the bacteria present at the center of the droplet residue. Mechanistic insights gained via our study can have far-reaching implications for bacterial infection through droplets, e.g., through open wounds.

Inanimate Surfaces as a Source of Hospital Infections Caused by Fungi, Bacteria and Viruses with Particular Emphasis on SARS-CoV-2

The carriers of nosocomial infections are the hands of medical personnel and inanimate surfaces. Both hands and surfaces may be contaminated as a result of contact with the patient, their body fluids, and touching contaminated surfaces in the patient's surroundings. Visually clean inanimate surfaces are an important source of pathogens. Microorganisms have properties thanks to which they can survive in unfavorable conditions, from a few days to several months. Bacteria, viruses and fungi are able to transmit from inanimate surfaces to the skin of the patient and the medical staff. These pathogens include SARS-CoV-2, which can survive on various types of inanimate surfaces, being a potential source of infection. By following the recommendations related to washing and disinfecting hands and surfaces, and using appropriate washing and disinfecting agents with a broad biocidal spectrum, high material compatibility and the shortest duration of action, we contribute to breaking the chain of nosocomial infections.

Study of the persistence of selected Gram-negative bacteria pathogens of healthcare-associated infections on hospital fabrics

BACKGROUND

The ability of healthcare associate infection (HAI) pathogens to persist on fomites is crucial to their transmission within the healthcare setting, this study evaluated the persistence of 3 common HAI pathogens on fabrics materials commonly used in healthcare settings.

METHODS

Persistence of bacteria species on fabric was investigate by inoculating standardized inoculum prepared from the clinical isolates of Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii on sterile swatches of 100% cotton, microfiber and polyester. Viable bacteria persisting on the inoculated fabrics were evaluated immediate after inoculation and subsequently at 96-hour interval for 32 days using the drop plate technique. The effect of moisture on the persistence of the studied bacteria isolates was also evaluated.

RESULTS

Between 3 and 6 log reduction in the viability of the inoculated bacteria cells were observed after 32 days of inoculation on fabrics. Generally, lower viable cells were recovered from the microfiber fabrics compared to others, while higher viable cells were recovered from wet fabrics compared to the dry fabrics in this study.

DISCUSSION AND CONCLUSIONS

This study demonstrated that HAI bacteria pathogens can persist for more than a month on hospital fabrics, and that their persistence can be enhanced by moisture.

Microbial Air Quality in Healthcare Facilities

There is increasing evidence that indoor air quality and contaminated surfaces provide an important potential source for transmission of pathogens in hospitals. Airborne hospital microorganisms are apparently harmless to healthy people. Nevertheless, healthcare settings are characterized by different environmental critical conditions and high infective risk, mainly due to the compromised immunologic conditions of the patients that make them more vulnerable to infections. Thus, spread, survival and persistence of microbial communities are important factors in hospital environments affecting health of inpatients as well as of medical and nursing staff. In this paper, airborne and aerosolized microorganisms and their presence in hospital environments are taken into consideration, and the factors that collectively contribute to defining the infection risk in these facilities are illustrated.

Bioburden contamination and Staphylococcus aureus colonization associated with firefighter's ambulances

Ambulance vehicles are an essential part of emergency clinical services. Bioburden control in ambulances, through cleaning and disinfection, is crucial to minimize hospital-acquired infections, cross contamination and exposure of patients and ambulances' crew. In Portugal, firefighter crews are responsible, besides fire extinction, for first aid and urgent pre-hospital treatment. This study assessed the bioburden in Portuguese firefighters' ambulances with a multi-approach protocol using active and passive sampling methods. Fungal resistance profile and mycotoxins detection in ambulances' ambient, and S. aureus (SA) prevalence and resistance profile in ambulances' ambient and colonization in workers were also investigated. Toxigenic fungi with clinical relevance, namely Aspergillus section Fumigati, were found on ambulance's air in the hazardous dimension range. Interestingly, surface contamination was higher after cleaning in several sampling sites. Prevalence of S. aureus was 3% in environmental samples, of which 2% were methicillin-sensitive (MSSA) and 1% methicillin-resistant (MRSA). About 2.07 fungal species were able to grow in at least one azole, ranging from one (44% samples) to five (6% samples) species in each azole. Mycotoxins were detected in mops and electrostatic dust cloths. Colonization by S. aureus in the firefighter crew was observed with a high associated prevalence, namely 48%, with a 24% prevalence of MSSA (8/33) and 21% of MRSA (7/33). Additional studies are needed to determine the potential risk of infection transmission between different vehicle fleets and under varying conditions of use. This will strengthen the paramedic sector's mission to save lives without putting their own health and safety at risk.

Persistence of Pathogens on Inanimate Surfaces: A Narrative Review

For the prevention of infectious diseases, knowledge about transmission routes is essential. In addition to respiratory, fecal-oral, and sexual transmission, the transfer of pathogens via surfaces plays a vital role for human pathogenic infections-especially nosocomial pathogens. Therefore, information about the survival of pathogens on surfaces can have direct implications on clinical measures, including hygiene guidelines and disinfection strategies. In this review, we reviewed the existing literature regarding viral, bacterial, and fungal persistence on inanimate surfaces. In particular, the current knowledge of the survival time and conditions of clinically relevant pathogens is summarized. While many pathogens persist only for hours, common nosocomial pathogens can survive for days to weeks under laboratory conditions and thereby potentially form a continuous source of transmission if no adequate inactivation procedures are performed.

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.

Perfil de resistencia genotípica y fenotípica presente en bacterias aisladas a partir de fómites en Armenia, Quindío-Colombia período junio-julio 2019

Introducción: La antibiótico-resistencia es un fenómeno por el cual las bacterias logran sobrevivir al tratamiento con antimicrobianos; con incidencia en ambientes intra y extrahospitalarios como: fuentes hídricas, sector agrario/ganadero y fómites. Objetivo: Describir bacterias presentes en fómites de alta circulación en una región centro-occidental de Colombia junto a su perfil de sensibilidad fenotípica y presencia de genes para betalactamasas tipo TEM-full, OXA-3 y SHV-full. Metodología: Se aislaron cepas bacterianas de billetes, pasamanos de escaleras eléctricas y botones de cajeros automáticos; se evaluó su perfil de sensibilidad fenotípica por medio de concentración mínima inhibitoria-técnica automatizada/Vitek2® y genes para betalactamasas tipo TEM-full, OXA-3 y SHV-full mediante PCR convencional. Resultados: Se obtuvo 30 aislados; Acinetobacter baumannii complex, fue la más común; el fómite con mayor aislados y resistencia fueron los billetes; el 53% portó al menos uno de los genes estudiados. Se identificaron bacterias gramnegativas con resistencia frente a: Imipinem, Piperacilina/Tazobactam, Colistina, Ceftazidima, Tigeciclina y Ceftriaxona; bacterias grampositivas con resistencia frente a: Quinupristina/Dalfopristina, Minociclina, Tetraciclina, Teicoplanina, Nitrofuratoina, Oxacilina, Clindamicina, Trimetropina-sulfametoxazol, y Minociclina. Conclusión: Teniendo en cuenta la circulación de cepas con estas resistencias, es importante la educación en la comunidad para evitar la adquisición o propagación de infecciones por manipulación inadecuada de fómites.

Eye-Catching Microbes-Polyphasic Analysis of the Microbiota on Microscope Oculars Verifies Their Role as Fomites

Microscopes are used in virtually every biological and medical laboratory. Previous cultivation-based studies have suggested that direct contact with microscope eyepieces increases the risk of eye infections. To obtain a deeper insight into the microbiota on oculars, we analysed 10 recently used university microscopes. Their left oculars were used for a cultivation-based approach, while the right oculars served for massive gene sequencing. After cleaning with isopropyl alcohol, the oculars were re-sampled and analysed again. All oculars were found to be contaminated with bacteria, with a maximum load of 1.7 × 10³ CFU cm^-2. MALDI Biotyping revealed mainly Cutibacterium (68%), Staphylococcus (14%) and Brevibacterium (10%), with the most abundant species being Cutibacterium acnes (13%) and Staphylococcus capitis (6%). Cleaning reduced the microbial load by up to 2 log scales. Within 10 uncleaned and 5 cleaned samples, 1480 ASVs were assigned to 10 phyla and 262 genera. The dominant genera before cleaning were Cutibacterium (78%), Paracoccus (13%), Pseudomonas (2%) and Acinetobacter (1%). The bacteriota composition on the cleaned oculars was similar; however, it probably largely represented dead bacteria. In summary, used oculars were significantly contaminated with skin and environmental bacteria, including potential pathogens. Regular cleaning is highly recommended to prevent eye and skin infections.

How long can nosocomial pathogens survive on textiles? A systematic review

Aims: Healthcare-associated infections linked to contaminated textiles are rare but underline their potential role as a source for transmission. The aim of the review was to summarize the experimental evidence on the survival and persistence of the different types of nosocomial pathogens on textiles.

Methods: A literature search was performed on MedLine. Original data on the survival of bacteria, mycobacteria, and fungi and persistence of viruses on textiles were evaluated.

Results: The survival of bacteria at room temperature was the longest on polyester (up to 206 days), whereas it was up to 90 days for some species on cotton and mixed fibers. Only low inocula of 100 CFU were found on all types of textiles with a short survival time of ≤3 days. Most bacterial species survived better at elevated air humidity. The infectivity of viruses on textiles is lost much faster at room temperature, typically within 2–4 weeks.

Conclusions: Contaminated textiles or fabrics may be a source of transmission for weeks. The presence of pathogens on the coats of healthcare workers is associated with the presence of pathogens on their hands, demonstrating the relevance of textile contamination in patient care.

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.

Bacteria on the Soles of Patient-Issued Nonskid Slipper Socks: An Overlooked Pathogen Spread Threat?

BACKGROUND

This is the first study to determine whether nonskid slipper socks in contact with the hospital floor and worn into bed contaminate bed linen.

PURPOSE

The main purpose of the study was to determine whether contamination of hospital linen occurred with bacteria transferred from the soles of nonskid slipper socks that have touched the floor.

METHODS

This study mimicked real patients walking on a hospital floor wearing slipper socks and getting back into bed with the slipper socks on. Swab samples were collected from the surfaces of the hospital floor, nonskid slipper sock bottoms, and bed linen in 2 Midwestern hospitals. From the samples, bacterial isolates were identified and tested for antibiotic resistance.

RESULTS

Isolates obtained from the samples were identified on all 3 surfaces at both hospitals, indicating spread of the bacteria from floor to the bed linen via the nonskid slipper socks. Antibiotic sensitivity test revealed that a significant number of isolates collected were resistant to at least 2 antibiotics tested.

CONCLUSION

This study demonstrates cross-contamination of bed linen with potentially pathogenic bacteria present on the hospital floor via contact with patient-worn nonskid slipper socks. A simple practice change regarding the wearing of slipper socks could play an important role in preventing pathogen transfer to the bed linen. Awareness of the likelihood of hand contamination after touching the sock bottoms that have come in contact with the hospital floor should also be considered.

The Role of Environmental Contamination in the Transmission of Nosocomial Pathogens and Healthcare-Associated Infections

PURPOSE OF REVIEW

The aim of this review is to highlight the role of environmental contamination in healthcare-associated infections (HAIs) and to discuss the most commonly implicated nosocomial pathogens.

RECENT FINDINGS

Recent studies suggest that environmental contamination plays a significant role in HAIs and in the unrecognized transmission of nosocomial pathogens during outbreaks, as well as ongoing sporadic transmission. Several pathogens can persist in the environment for extended periods and serve as vehicles of transmission and dissemination in the hospital setting. Cross-transmission of these pathogens can occur via hands of healthcare workers, who become contaminated directly from patient contact or indirectly by touching contaminated environmental surfaces. Less commonly, a patient could become colonized by direct contact with a contaminated environmental surface. This review describes the role of environmental contamination in HAIs and provides context for reinforcing the importance of hand hygiene and environmental decontamination for the prevention and control of HAIs.

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.