All healthcare facilities and hospitals need to step up their hand washing techniques as well as use of alcohol based hand sanitizers after reports of emergence of hospital super bacteria that are becoming more tolerant to alcohol.
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Microbiologists explain that most hand sanitizers contain alcohols such as isopropanol as their key component. Use of hand sanitizers routinely in the hospital set ups has prevented the rising rates of hospital infections of methicillin-resistant Staphylococcus aureus (MRSA) to an extent. However while these sanitizers have to an extent prevented MRSA infections, there is a parallel growth of vancomycin-resistant enterococci, or VRE that is becoming tolerant to alcohol.
The results of the research are published in the latest issue of the journal Science Translational Medicine.
According to Prof Timothy Stinear, co-author of the research from the University of Melbourne that pointed out this new development, this should be a “wake up call” to the infection control teams at the hospitals worldwide. He said that if VRE is to be controlled then there should be alternative techniques of cleansing the hands than using alcohol based hand sanitizers. He said that chlorine based disinfectants and screening and isolation of patients can be good alternatives.
According to Stinear, VRE is most commonly caused by the Enterococcus faecium and cases are on the rise in Australia and England. Many of these cases can become life threatening and difficult to treat. The VRE, he explained gets colonized within the patient’s gut and spreads to the blood vessels leading to sepsis.
This is resistant to almost all antibiotics and is thus very difficult to get rid of he said. These bacteria can also migrate within the blood stream to get lodged over the heart valves and prosthetic devices. He explained that healthy individuals do not get infected with VRE and it is only those with a supressed or compromised immunity that are at risk.
In the study the team of researchers found Enterococcus faecium bacteria from patients. They exposed a total of 139 samples of these bacteria in the labs to an isopropanol-based solution for five minutes.
The samples came from different patients in two different hospitals in Melbourne between 1997 and 2015. Alcohol based hand sanitizers came into use from the early 2000s and by 2015 there was a ten-fold rise in its uptake.
The team noted that with passage of time the bacterial samples seemed to have become more and more tolerant to alcohol. Stinear said that after 2010, there was a ten times rise in tolerance to alcohol when compared to earlier strains.
The team then noted that the alcohol concentration they had used in the lab was more dilute than the actual solutions used in hospitals.
Then they set up another round of experiments to see if the bacteria could resist the commonly used concentrations of alcohol. Four isolates of the bacteria were taken and two of these were tolerant to alcohol in the earlier experiment.
These were spread in different cages and then they were wiped using the isopropanol wipes of the concentration used in hospitals. Mice were allowed to stay in the cages for an hour before they were taken out. The guts of the mice were tested for the bacteria after a week.
The results showed that the alcohol tolerant strains were not eliminated with the isopropanol wipes and the mice that were exposed to these strains got infected. Stinear said that this proves that these bacteria can escape the “standard infection control procedures” followed in the hospitals.
The team is now working on studying the genetic mutations in these alcohol resistant strains of the Enterococcus faecium isolates to understand how they are evolving to resist disinfection efforts.
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