Microbiological contamination of hospital textile, effectiveness of new laundry detergent

Microbiological contamination of hospital textile, effectiveness of new laundry detergent

Keywords: textile hygiene; disinfection; hospital-acquired infections

Lak.Mandana, Asem.Nazila,

Padideh Shimi Gharb, Golrang Industrial Group

4th floor, no 22, Yas building, Tavanir St, Valiasr St. Tehran, Iran

Introduction:

Hospital linen is clearly recognized as a potential reservoir for microorganisms and could be a vector of disease transmission. Contaminated textiles and fabrics often contain high numbers of microorganisms. During laundering, along with new laundry powder, chemical inactivation of microbes on fabrics can be achieved by using new bleach component. Surfactant in formulation will also exert some chemical inactivation action against certain species.

Materials and methods:

Germ carriers made of cotton fabric are contaminated with a test suspension of microorganisms. After drying the carriers are transferred into cotton bags and then the disinfection process in the washing machine is performed. At the end of the disinfection step of the procedure, each carrier is transferred into a separate tube containing neutralizer. The number of surviving bacteria in each sample is determined and the reduction rate is calculated.

Results:

Results showed that there was a reduction of bacteria with 7-8 log10 CFU after 40 min exposure to 5 g/l detergent powder in laundering process.

Discussion:

Several tons of laundry is produced in hospitals every day. Textiles are a common material in healthcare facilities; therefore it is important that they do not pose as a vehicle for the transfer of pathogens to patients or hospital workers. Thus laundering is necessary. During laundering, chemical inactivation of microbes on fabrics achieved the washing cycle along with new laundry powder reduced the number of bacteria with 7-8 log10 CFU


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Microbiological contamination of hospital textile, effectiveness of new laundry detergent

Mandana Lak*, Nazila Asem, Babak Babajanzadeh, Majid Abedi Iran, Tehran, Golrang Industrial Group, Padideh Shimi Gharb

M.lak @psgiran.com

Introduction:

Hospital linen is clearly recognized as a potential reservoir for microorganisms and could be a vector of disease transmission. Contaminated textiles and fabrics often contain high numbers of microorganisms from body substances. Textiles are a common material in healthcare facilities; therefore it is important that they do not pose as a vehicle for the transfer of pathogens to patients or hospital workers. During the course of use hospital textiles become contaminated and laundering is necessary. Laundering of healthcare textiles is most commonly adequate, but in some instances, due to inappropriate disinfection or subsequent recontamination, the textiles may become a contaminated inanimate surface with the possibility to transfer pathogens.

 Materials and methods:

  • test organisms:
    • Pseudomonas aeruginosa ATCC 15442.
    • Escherichia coli ATCC 10536.
    • Staphylococcus aureus ATCC 6538.
    • Enterococcus hirae ATCC 10541.
  • Cotton carriers: The germ carriers are prepared by using standard cotton fabric thoroughly cooked in double-distilled water three times. The fabric is cut into 1 cm2 cotton carriers and Autoclaved.
  • Bacterial test suspension: For harvesting the bacteria, 10 ml of 0,9 % NaCl solution are pipetted into the plates and the bacteria are washed off, resuspended and centrifuged 15 min at 3000g. The number of cells in the suspension shall be at least 1,5 x 109 cfu/ml.
  • Inoculation of the carriers: The germ carriers are dipped in the test suspension to wet them completely. The carriers should stay in the suspension for 15 min. Subsequently the germ carriers are transferred in open Petri dishes until visual dryness. The cleaning and disinfection cycle shall be performed in accordance to the pre-designed procedure process temperature 40C,contact time 30 min, 5% laundry powder in washing machine.
  • Calculation: Incubate the plates of test organisms, Calculate the numbers of cfu/ml in the test suspension.

Results:

Microbial counts of the test suspension N0 and validation suspension Nv0

Microbial counts after the treatment with the laundry detergent Na

Calculations: Microbial reduction rate per test germ:

lgR = lgN0 – lgNa

Microbial reduction for E. coli ATCC 10536

Microbial reduction for S. aureus ATCC 6538

Microbial reduction for E. hirae ATCC 10541

Microbial reduction for P. aeruginosa ATCC 15442

Discussion:

Antibacterial action of powder laundry detergent: The laundry detergent was tested according to a protocol close to the standard EN 16616:2015. For the test bacteria S. aureus (reduction rate > 5.15 log10), E. coli (reduction rate >5.30 log10) and P. aeruginosa (reduction rate > 5.17 log10), a bacterial reduction of > 5 log10 steps or 99.999% was detected. This corresponds to the requirement of EN 16616:2015 for a disinfectant (> 5 log10-step reduction or 99.999 % reduction) and shows clearly an antibacterial action of the laundry detergent. For the test bacteria Enterococcus hirae the requirement of a 5 log10-step reduction could barely be achieved (reduction rate > 4.79 log10). However, all tested bacteria were reduced for > 4 log10 -steps or 99,99%, which is a good result for a household laundering process were a disinfecting action is not needed.

Conclusion:

The powder laundry detergent shows an antimicrobial action of > 4.7 log10 -steps or >99.99% against the test bacteria S. aureus, E. coli, E. hirae and P. aeruginosa. The requirements of the standard EN 16616:2015 of a 5 log10 -reduction or 99.999% could not be met by all test bacteria. Enterococcus hirae was the limiting test germ in this test