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 Table of Contents  
Year : 2022  |  Volume : 10  |  Issue : 1  |  Page : 6-9

Bacterial counts of hospital linen and effectiveness of laundry process: A need for consensus on microbial sterility of hospital linen

1 Department of Hospital Administration, Post Graduate Institute of Medical Education and Research, Chandigarh, Punjab, India
2 Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh; Department of Microbiology, All India Institute of Medical Sciences, Bathinda, Punjab, India
3 Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, Punjab, India

Date of Submission25-Jan-2022
Date of Acceptance13-Sep-2022
Date of Web Publication12-Nov-2022

Correspondence Address:
Dr. Raman Sharma
Department of Hospital Administration, Post Graduate Institute of Medical Education and Research, Chandigarh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpsic.jpsic_1_22

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Background: Health care linen is a source of healthcare-associated infections. Hospital laundry services play a vital role in linen decontamination. Effective laundry is essential in preventing hospital-acquired infections, especially in multidrug-resistant organisms.
Aims and Objectives: The study aimed to check the microbial load in linen after the laundry process and the during the supply chain in the hospital. We investigated the bacterial load in linen before and after the laundering process and the linen from stored linen banks.
Materials and Methods: Linens (n=125) from the hospital were collected in different stages of the laundry process [31 linen before decontamination; 94 linen after decontamination (Post washing = 30; Linen Bank = 34; Ward 30)]. A square inch of linen from each linen was vortexed in normal saline, and colony forming units (CFU)/inch of linen were calculated using appropriate media. The identification and susceptibility of organisms were performed using MALDI-TOF MS and CLSI disk diffusion methods, respectively. The difference in the load of the organism was analysed between different stages of the laundry and storage process.
Results: We found that100% of pre-decontamination linen harbour viable organisms (22.59% including multidrug-resistant pathogenic organisms: MDROs), which decreased to 40% (no MDROs) post-decontamination. The overall load was reduced by a factor of 103.77.
Conclusion: The microbial contamination of linen is common, and there is an urgent need to develop consensus on the microbial examination frequency and acceptable range of organisms on hospital linen worldwide.

Keywords: Bacterial load, decontamination, hospital, hospital linen, laundry

How to cite this article:
Sharma R, Krishnamoorthi S, Kumar A, Biswal M, Koushal V. Bacterial counts of hospital linen and effectiveness of laundry process: A need for consensus on microbial sterility of hospital linen. J Patient Saf Infect Control 2022;10:6-9

How to cite this URL:
Sharma R, Krishnamoorthi S, Kumar A, Biswal M, Koushal V. Bacterial counts of hospital linen and effectiveness of laundry process: A need for consensus on microbial sterility of hospital linen. J Patient Saf Infect Control [serial online] 2022 [cited 2023 Jun 7];10:6-9. Available from: https://www.jpsiconline.com/text.asp?2022/10/1/6/361001

  Introduction Top

Hospital linen has been linked to the numerous outbreaks of hospital-acquired infections (HAIs). The laundry is an indispensable allied health service that ensures prevention as well as containment of hospital infections by providing clean health care linen.[1],[2] Occupational safety and health administration (OSHA) has defined laundry contamination as 'laundry contaminated with blood or bodily secretions or sharps'. The contamination by the bacteria can be as high as 106–108 colony-forming units (CFU)/100 cm2 of fabric leading to nosocomial transmission.[3] Whether the level of linen contamination correlates with HAI risk is not known, but studies of contamination on hard surfaces have used <2.5 CFU/cm2 aerobic colonies and <1 CFU/cm2 for specific indicator organisms as acceptable limits. It is not clearly known if these levels for hard surface contamination can be applied to hospital linen that is in contact with patients.[4]

The present study was carried out in one of the multispecialty tertiary care hospital of North India to analyse the effectiveness of laundering on linen bacterial decontamination.

  Materials and Methods Top

Laundering parameters

Laundering process of the institute included handling and collection of soiled linen with universal precaution from different hospital areas in leak-resistant bags, transportation to laundry and sorting of those linen from hard objects for further processing. The linens items are agitated in water to remove substantial amount of microorganisms before washing step. For washing various materials used, also acting as antimicrobial measures, include detergents (4 g/kg linen), dry cleaning agents, bleaching powder (1.5 g, i.e. chlorine residual levels of 50–150 ppm), soda ash (8.5 g/kg linen) and whitening agents (0.65 g neel). The washing cycle of minimum of 45 min at the water temperature of at least 75°C–80°C is followed. After washing and hydro-extraction process, cleaned and wet clothing are dried in flat bed steam press, ironed at a temperature of 160°C and then properly packed to prevent inadvertent contamination during loading, transportation, unloading and stored in linen bank or delivered to wards.

Linen sample processing for bacterial count

A total of 125 linen items including bed sheets (n = 70) and personal-protective gowns (55) were collected from hospital laundry before and after wash (n = 31 and 30, respectively), linen bank after wash (n = 34) and wards after final distribution (n = 30) over 5 months (February − June of 2018).

To collect the samples, the linen was packed in sterile wrapper and transported to the hospital infection surveillance laboratory in the department of medical microbiology for its qualitative and quantitative microbiological assessment. Ethical approval was taken from the Institutional Ethics Committee to conduct the study.

All linen samples were processed in biosafety cabinet level IIB. One square inch of each linen sample was cut using sterile scissors and transferred into 15 ml Falcon tube containing 4 ml of normal saline. The tubes were agitated using a vortex machine for 15 min. One microlitre (1μl) of elute was inoculated on 5% sheep blood and MacConkey agar and incubated aerobically at 37°C for 48 h. Thus, CFUs per square inch of linen (CFU/square inch) were calculated from the inoculated culture plate semi quantitatively and the organisms grown on culture were identified by Bruker Biotyper MALDI-TOF with on-plate extraction protocol. Spectra acquired was recorded in the positive linear mode at 20 Hz laser frequency, ion source (1 Voltage of 20 kV), ion source (2 Voltages of 8.5 kV), 2,000 to 20,000 Da mass range.

The median and range of bacterial load in both the groups of linen (prior and after decontamination process) were calculated. All organisms isolated which are known pathogens were tested for antibiotic-susceptibility pattern according to the Clinical Laboratory Standard Institute.

  Results Top

Bacterial load assessment

Bacterial counts in pre-decontamination linen

All 31 linen samples collected before decontamination process grew bacteria with range of 103.477 − 106 CFU/square inch with a median of 103.778 CFU/square inch. Known pathogenic organisms were present in the range of 0 −106 (median of 0) [Table 1]. Seven linen samples had pathogenic bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Acinetobacter junii, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus aureus and Staphylococcus warneri), whereas 24 had non-pathogenic organisms (Micrococcus luteus, Exiguobacterium aurentiacum, Brevundimonas vesicularis, Pseudomonas monteilii, Kocuria species, Arthrobacter spp. and Bacillus spp).
Table 1: Microbiological quality of linen obtained from different area

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Bacterial counts in post-decontamination linen

Fifty-four of 94 linen samples (57.44%) collected after the decontamination process were found having bacterial growth. Viable organisms per square inch of linen were found having median value of 102.602 CFU/square inch with the range of 0 − 105.6 CFU/square inch [Table 1]. The median of pathogens per square inch of linen was 0 with range of 0–105.6 CFU/square inch.

Out of 54 linen items pathogens (S. hominis, S. aureus, S. warneri, K. pneumoniae and A. baumannii,) were found in 15 (27.77%) linen items, whereas opportunists (M. luteus, E. aurentiacum and aerobic spore bearing bacilli) were detected in the remaining 39 samples.

Effectiveness of decontamination process

Out of the total samples (94) tested in post-decontamination phase, 42.5% of samples were found to be sterile (103−106 reduction of bacterial load compared to pre-decontamination load). Although 57.4% of samples still harboured approximately 102−105 CFU/square inch, there was a log10 reduction factor of 1 when compared to pre-decontamination load. In total there was 101.176 reduction achieved in post-decontamination process compared to pre-decontamination process. It was found that there was 103.778 reduction post-wash in laundry as compared to linen bank storage (reduced by a factor of 100.787) and end level usage, i.e. wards (reduced by a factor of 100.875) [Table 1].

The overall viable bacterial load of all pre-decontamination samples (100%) was more than 103 CFU/square inch. The percentage of samples with load more than 103/square inch was reduced to 36.63% after washing step and again increased to 49.99% and 46.66% in linen bank and end level usage, respectively [Figure 1]a. When considering bacterial load of pathogenic organism, 22.56% of pre-decontamination samples harboured more than 103/square inch organism and the load was reduced to 9.99% after washing step and again increased to 11.76% and 6.66% in linen bank and end level usage, respectively [Figure 1]b.
Figure 1: Percentage of linen showing log reduction from baseline levels. (a) All viable organisms. (b) All pathogenic organisms

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Antimicrobial susceptibility of pathogenic organisms isolated

Eight out of nine well-documented pathogenic isolates (88.88%) from linen collected before decontamination exhibited multidrug-resistant organisms (MDROs). Twelve out of 15 pathogens isolated post-decontamination process from linen bank and end user wards were MDROs but none from immediate post-wash linens (data can be provided).

  Discussion Top

In the recent years, the impact of laundering to reduce microbial contamination has mounted and basis for this on a large extent is the increased frequency of outbreaks caused by multi-resistant bacteria in healthcare as well as in community. The present study was aimed to analyse the effectiveness of laundering process in a professional laundry for bacterial decontamination. It is a well-known fact that different variables affect laundering outcome namely type of microorganisms, washing machine, type of linen, laundering equipment, quality of detergents used, transportation and storage of linen in user areas, etc.[5] Some studies have just focused on washing temperature, washing duration, whereas, others have emphasised on drying temperature, ironing or the energy costs.[6] In a study by Hall TJ with conventional washing machines used in healthcare facilities, temperature was frequently lowered to 30°C-40°C so as not to damage the clothes, but, at these temperatures, the risk of laundry malodour and contamination is obvious.[7] In the present study, laundering had been done at the temperatures of 57.2°C –62.7°C (135°F–145°F) followed by ironing of linen at a temperature of 160°C, and it was found sufficient to get the significant linen decontamination results.

There are the reports of contaminated linen with bacterial loads of 106 − 108 CFU/100 cm2 of linen leading to HAIs and the effect of laundering in minimising this risk.[3] In the present study, in post-decontamination phase, 42.5% of samples were found to be sterile (bacterial load reduced by a factor of 103 − 106 compared to pre-decontamination load), whereas, in 57.4% of samples there was a log10 reduction factor of 1 as compared to pre-decontamination load (reduced by a factor of 102 − 105 CFU/square inch).

This study shows that although washing procedures are sufficiently effective for the removal of microorganisms, recontamination may occur even after washing and before contact with the patient. It was also observed that there were slight increases in those MDROs after post-wash step while storing in linen bank and end user level (i.e., wards) which can be explained due to storage at high ambient temperature, frequent handling while packing and transportation. The median load in post-wash samples was 0 (interquartile range-103.607) (i.e. reduced by a factor of 103.77 reductions in post-wash step).

In a study by Hambraeus, it was found that contamination may also occur post-wash and before contact with the patient as 14% of clean clothes were found to be contaminated by S. aureus, and 10% by Clostridium species.[8] The study of Wong found that counts on clean white coats were around 2 CFU/25 cm2, whereas on the contrary, other studies found bed sheets sampled before use did not appear to carry microbial loads.[9] In the present study itself, 42.5% of linen samples leaving the laundry appear to be free from contamination although were not claimed to be sterile, whereas in 57.4% of samples still harboured microorganisms approximately 102-105 CFU/square inch. In other words, from pre-contamination sample load of 100% (load more than 103 CFU/square inch), it reduced to 36.63% (with load more than 103 CFU/square inch) post-wash and it again increased to 49.99% and 46.66% in linen bank and end level usage respectively and most of these bacterial growth found on 'clean' linen were likely to be originated during transporting, storage in linen bank and wards itself. Moreover, most of these microorganisms found in the linen samples were the usual skin microflora or saprophytic bacteria from the environment. In the studies of Srinivasan M, Banville RR, Hooker EA most prevalent microorganisms found were Gram-positive cocci, whereas, studies of Treakle AM, Perry C, Babb JR focusing specifically on HAI prevalent pathogens found were S. aureus or enterococci. In the present study, both pathogenic and opportunistic organisms were found. In the study by Sundermann et al., linen contaminated with Mucorales in 47% of transplant and cancer hospitals failed to achieve 'hygienically clean' standards in 20% of centres post-wash and it was suggested that healthcare professionals should develop reasonable standards for producing, testing and certifying hygienically clean linen that balances patient safety, workflow and costs.[10] Although there is a lack of clear cutoffs for organism load to define the HCL as hygienically clean, US Pharmacopeia 61 and RAL-GZ-992/2 methods were used in this study.[10] The study looked into the contamination by moulds only, and the total aerobic bacterial count was not evaluated.

There is, however, no guideline on the acceptable level of bacterial (both pathogenic and non-pathogenic) organisms on processed, ready-to-use hospital linen. How clean should hospital linen be? It is the need of the hour to work towards achieving a consensus on the same.

  Conclusion Top

In our laundry, the freshly-laundered linen was showing more than 10% contamination of MDROs overall, although individually, some MDROs were found to be much less abundant. To conclude, microbial contamination of linen is common and there is an urgent need to develop the consensus on the microbial examination frequency of linen and acceptable range of organism on hospital line worldwide.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Gomes Libert Anil Sharma Yashpal SR. Support services. In: Anil GL, RK Sarma, Yashpal S, editors. Hospital Administration: Principles and Practice SE. Ch. 05. New Delhi, India: Jaypee Brothers Pvt Ltd; 2013. p. 94-178.  Back to cited text no. 1
Sakharkar BM, editor. Role of hospitals in health care. In: Principles of Hospital Administration and Planning SE. Ch. 01. New Delhi, India: Jaypee Brothers Pvt Ltd; 2009. p. 1-20.  Back to cited text no. 2
Blaser MJ, Smith PF, Cody HJ, Wang WL, LaForce FM. Killing of fabric-associated bacteria in hospital laundry by low-temperature washing. J Infect Dis 1984;149:48-57.  Back to cited text no. 3
Dancer SJ. How do we assess hospital cleaning? A proposal for microbiological standards for surface hygiene in hospitals. J Hosp Infect 2004;56:10-5.  Back to cited text no. 4
Christian RR, Manchester JT, Mellor MT. Bacteriological quality of fabrics washed at lower-than-standard temperatures in a hospital laundry facility. Appl Environ Microbiol 1983;45:591-7.  Back to cited text no. 5
Wilcox MH, Jones BL. Enterococci and hospital laundry. Lancet 1995;345:594.  Back to cited text no. 6
Hall TJ, Wren MW, Jeanes A, Gant VA. Decontamination of laundry at low temperature with CuWB50, a novel copper-based biocidal compound. Am J Infect Control 2009;37:478-83.  Back to cited text no. 7
Hambraeus A, Bengtsson S, Laurell G. Bacterial contamination in a modern operating suite. 4. Bacterial contamination of clothes worn in the suite. J Hyg (Lond) 1978;80:175-81.  Back to cited text no. 8
Malnick S, Bardenstein R, Huszar M, Gabbay J, Borkow G. Pyjamas and sheets as a potential source of nosocomial pathogens. J Hosp Infect 2008;70:89-92.  Back to cited text no. 9
Sundermann AJ, Clancy CJ, Pasculle AW, Liu G, Cumbie RB, Driscoll E, et al. How clean is the linen at my hospital? The mucorales on unclean linen discovery study of large United States transplant and cancer centers. Clin Infect Dis 2019;68:850-3.  Back to cited text no. 10


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  [Table 1]


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