Textiles as fomites in the healthcare system

Factors affecting biofilm formation by bacteria on fabrics

Fabrics act as fomites for microorganisms, thereby playing a significant role in infection transmission, especially in the healthcare and hospitality sectors. This study aimed to examine the biofilm formation ability of four nosocomial infection-causing bacteria (Acinetobacter calcoaceticus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) on cotton, polyester, polyester-cotton blend, silk, wool, viscose, and nylon, used frequently in the healthcare sector, by qualitative and quantitative methods. The impact of temperature, pH, and relative humidity (RH) on biofilm formation was also assessed. P. aeruginosa and S. aureus were strong biofilm producers, while E. coli produced weak biofilm. Wool (maximum roughness) showed the highest bacterial load, while silk (lowest roughness) showed the least. P. aeruginosa exhibited a higher load on all fabrics, than other test bacteria. Extracellular polymeric substances were characterized by infrared spectroscopy. Roughness of biofilms was assessed by atomic force microscopy. For biofilm formation, optimum temperature, pH, and RH were 30 °C, 7.0, and 62%, respectively. MgCl2 and CaCl2 were the most effective in removing bacterial biofilm. In conclusion, biofilm formation was observed to be influenced by the type of fabric, bacteria, and environmental conditions. Implementing recommended guidelines for the effective disinfection of fabrics is crucial to curb the risk of nosocomial infections. In addition, designing modified healthcare fabrics that inhibit pathogen load could be an effective method to mitigate the transmission of infections.

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.

Enhanced bactericidal performance of textiles through compound antimicrobial agents

This study aims to explore the essential functional requirements associated with controlling the proliferation of microbes in the domain of textiles used in public health areas. Herein, three antimicrobial agents, specifically iodopropylbutylcarbamate (IPBC), 1-hydroxypyridine-2-thioketone zinc (ZPT), and 2-octyl-3-isothiazolinone (OIT), were chosen for fabric finishing based on their notable effectiveness, minimal toxicity, cost-efficiency, and chemical stability. Utilizing Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as representative bacterial strains, the Minimum Inhibitory Concentration (MIC50) of individual and combined antimicrobial agents was measured, and their antimicrobial effectiveness was rigorously evaluated. Concurrently, the antimicrobial effectiveness, whiteness, and mechanical durability of the fabric following antimicrobial treatment were thoroughly examined. The results demonstrate that some combinations of the three antimicrobial agents elicit additive effects on both S. aureus and E. coli. Notably, at an equivalent ratio of IPBC, ZPT, and OIT and a total concentration of 0.2 wt. %, the inhibition rates against both bacterial strains surpass 99%. Upon application to nylon fabric, the treated material demonstrates significant antimicrobial properties, with minimal reduction observed in the whiteness and tensile strength of the treated nylon. This study provides practicable strategies relevant to the production of textiles endowed with antimicrobial properties.

Poly(Allylamine Hydrochloride) and ZnO Nanohybrid Coating for the Development of Hydrophobic, Antibacterial, and Biocompatible Textiles

In healthcare facilities, infections caused by Staphylococcus aureus (S. aureus) from textile materials are a cause for concern, and nanomaterials are one of the solutions; however, their impact on safety and biocompatibility with the human body must not be neglected. This study aimed to develop a novel multilayer coating with poly(allylamine hydrochloride) (PAH) and immobilized ZnO nanoparticles (ZnO NPs) to make efficient antibacterial and biocompatible cotton, polyester, and nylon textiles. For this purpose, the coated textiles were characterized with profilometry, contact angles, and electrokinetic analyzer measurements. The ZnO NPs on the textiles were analyzed by scanning electron microscopy and inductively coupled plasma mass spectrometry. The antibacterial tests were conducted with S. aureus and biocompatibility with immortalized human keratinocyte cells. The results demonstrated successful PAH/ZnO coating formation on the textiles, demonstrating weak hydrophobic properties. Furthermore, PAH multilayers caused complete ZnO NP immobilization on the coated textiles. All coated textiles showed strong growth inhibition (2-3-log reduction) in planktonic and adhered S. aureus cells. The bacterial viability was reduced by more than 99%. Cotton, due to its better ZnO NP adherence, demonstrated a slightly higher antibacterial performance than polyester and nylon. The coating procedure enables the binding of ZnO NPs in an amount (<30 µg cm-2) that, after complete dissolution, is significantly below the concentration causing cytotoxicity (10 µg mL-1).