In the field of healthcare, practitioners are vigilant in hand-washing as they want to avoid the spread of infection. In fact, it is common and expected of healthcare providers to wash their hands in between patients.

However, studies have shown that sinks may contain harmful bacteria. This has stirred up speculation that hand-washing in hospital sinks may even do more harm than good.

Culturing hospital sinks' drain pipes

There have been several reports that revealed the growth of drug-resistant bacteria in the drainpipes of hospital sinks. After coming into contact with a patient, the healthcare provider would proceed to wash his hands. The purpose of this is to wash off the pathogens that his hands may have picked up.

However, the pathogens that were essentially washed off would then stay within the drain pipe or P-trap of the sink. It is good to note that intravenous fluids, drinks, and feeding supplements are often emptied out in hospital sinks. These substances serve as nutrients for bacteria, causing it to grow and spread to other sinks.

Dr. Amy Mathers from the University of Virginia School of Medicine, together with several other researchers, conducted a study to determine how pipe-dwelling bacteria affected patients. They performed this by first setting up five hospital sinks, with one harbouring E. coli in the drainage.

The researchers later began a dispersion method. This was where they noted that the ‘splash’ from the water upon turning on the faucet causes the bacteria to disperse.

This showed that dispersion of the bacteria would reach the soap dishes as well as the faucet itself. With the bacteria then transferred to these objects, it will then spread to the healthcare providers’ hands and consequently to the hands of the patient. The study was published earlier this year.

The spread of ESBL may infect patients

A 2014 study by I. Wolf and colleagues looked into the spread of extended-spectrum beta lactamase (ESBL) from the room sink to the patient. Over a 20 week screening period, four ICU patients were infected with ESBL.

It was later established that the transfer had taken place from the sink to the patient. It was noted that in four ICU patients, transmission of the infection was from the hospital sink to the patient.

This was discovered as the sinks were noted to be identifiable sources of ESBLs before the ICU transfer. In fact, one of these patients were infected by ESBL-positive E. cloacae and unfortunately passed away.

How hospital sinks should be cleansed

ESBL is a common isolate and has been colonising ICU patients for several years to date. Cleaning sinks with chlorine or other disinfectants have shown to be ineffective, due to their reduced sensitivity or resistance to ESBL.

Studies have shown that the bacteria in a biofilm has reduced sensitivity to chlorine and is deemed as ‘not completely effective’ in disinfecting. A solution that seemed more permanent was to substitute sinks or to change the siphons with new ones.

Another was the introduction of self-disinfecting siphons. These are made to prevent the growth of biofilm in sinks which serve as the medium for growth of these organisms.

The cleansing process is done through heating and ultrasound, electromagnetic cleansing and antibacterial coating. It is deemed to be cost-effective, as it was likely to decrease the emergence of hospital acquired infections and hospital stays due to the faster recovery of patients. MIMS

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