For the first time in history, researchers have identified a washing machine as a reservoir of multi-antibiotics resistant pathogens. The pathogens, identified as a Klebsiella oxytoca clone, were transferred several times to newborns in neonatal intensive care in a German pediatric hospital. The transmission of the disease was only interrupted after the washing machine was removed from the hospital. The study was published in the journal Applied and Environmental Microbiology.
According to first author Ricarda M. Schmithausen, PhD it was a very unusual case for the hospital because the transmission took place in a domestic washing machine. Hospitals generally use special washing machines and washing processes that use high-temperature washing and disinfection products in accordance with German hospital hygiene directives.
This case could end up influencing how domestic washing machines are used said Dr. Schmithausen, Medical Director of the Institute of Hygiene and Public Health. The temperature of the water used in household washing machines falls to well below 60°C (140°F) to save energy, making them less deadly for pathogens. According to the report, resistance genes, as well as various microorganisms, can persist in domestic washing machines at reduced temperatures.
Elderly people with open wounds or bladder catheters, or younger people who suffer from severe wounds or infections, washing should be done at higher temperatures or with effective disinfectants to prevent the transmission of dangerous pathogens said Martin Exner, MD, Chairman of the Institute for Hygiene and Public Health. This is an increasing challenge for hygienists, as the number of people receiving nursing care from family members continues to rise.
In the hospital where the washing machine caused the transmission Klebsiella oxytoca, standard screening procedures showed the presence of pathogens in intensive care children. The researchers eventually identified the source of the pathogens in the washing machine after having found no contaminants in the incubators or carriers amongst the medical staff that was in contact with the babies.
The clothes that carried the infection K. oxytoca to the babies were caps and socks which were used to help them stay warm in incubators, because newborns can quickly get cold, even in incubators.
The researchers believed that the pathogens were distributed to the clothes after the washing process, by the remaining water on the rubber mantle or through the final rinsing process in which unheated, non-detergent water flowed through the detergent chamber. The study advises that changes in the design of the washing machine to prevent the accumulation of water in which micro-organisms may ensue and contaminate clothing. Though, it is not yet known how and from what source the pathogens entered the washing machine.
Although the Infants in the intensive care units were colonized, they did not get infected with K. oxytoc. Colonization means that the pathogens are harmless, either because they have not yet attacked the tissues in which they can cause disease, or because the immune system prevented that from happening.