A study found that hospital sink drains harbor dangerous bacteria, including antibiotic-resistant strains.
Despite thorough cleaning, bacteria persist and spread, posing risks to vulnerable patients. Some strains even resist last-resort antibiotics, highlighting a major public health concern.
Deadly Infections Lurking in Hospitals
When we go to the hospital, we expect to get better — not to leave with a new infection. Yet, healthcare-associated infections (HAIs) are a growing global problem, consuming an estimated 6% of hospital budgets worldwide. In the European Union alone, HAIs lead to over 3.5 million cases annually, causing 2.5 million disability-adjusted life years, costing up to €24 billion (~$25 billion), and contributing to 90,000 deaths. In the United States, they rank as the sixth leading cause of death.
HAIs spread more easily in patients with weakened immune systems and in hospitals where hygiene protocols are not strictly followed. Additionally, the widespread use of antibiotics in hospitals promotes the survival of resistant bacteria. When these bacteria carry resistance genes on mobile genetic elements, they can transfer those traits to other bacterial species, increasing the risk of new and potentially more dangerous infections.
Bacteria Hiding in Hospital Sinks
“Here we show that hospital sink drains host bacterial populations that change over time, despite impeccable cleaning protocols in the particular hospital we looked at,” said Dr. Margarita Gomila, a professor at the University of the Balearic Islands in Spain, and the senior author of a study in Frontiers in Microbiology.
“These results highlight that controlling bacterial growth in drains, and preventing colonization by new strains of such hard-to-disinfect niches, is likely a global problem.”
Rigorous Cleaning Protocols, But Are They Enough?
Gomila and her coworkers focused on sink drains in a single modern university hospital on the island of Majorca, built in 2001 and managed by the health service of the Balearic Islands. Cleaning protocols there are state-of-the-art: sinks and their drains are routinely cleaned with bleach, as well as disinfected with chemicals and pressurized steam every fortnight, or every month in non-patient areas. Once a year, drainpipes are hyperchlorinated at low temperatures.
Four times between February 2022 and February 2023, they used cotton swabs to sample six drains in each of five wards: two for intensive care, including a brand-new one; one ward each for hematology, short stays, and general medicine; as well as a microbiology laboratory. They cultured the sampled bacteria on five different media and at two different temperatures, and identified the resulting 1,058 isolates with DNA barcoding and mass spectrometry. They then used an automated platform to test whether each of the 219 isolates was resistant to a range of antibiotics.
Diverse and Persistent Bacterial Colonies
The authors identified a total of 67 different species from the drains. The diversity in most drains went up and down over time with no clear pattern – seasonal or otherwise. The greatest diversity occurred in general medicine and intensive care, while the fewest isolates were found in the microbiology laboratory. Strikingly, the new intensive care unit, which opened in July 2022, already showed a high level of bacterial diversity from the opening, on a par with its longer-established twin.
The Most Dangerous Pathogens Found
Dominant across wards were six Stenotrophomonas species as well as Pseudomonas aeruginosa, a pathogen known to cause ventilator-associated pneumonia and sepsis, and characterized by the WHO as one of the greatest threats to humans in terms of antibiotic resistance. At least 16 other Pseudomonas species were also found at various times and in various wards, but especially in the short-stay ward.
Other notorious hospital-associated pathogens found repeatedly were Klebsiella pneumoniae in the general medicine ward, Acinetobacter johnsonii and Acinetobacter ursingii in general medicine and intensive care, Enterobacter mori and Enterobacter quasiroggenkampii in the short-stay ward, and Staphylococcus aureus in intensive care and hematology.
“The bacteria we found may originate from many sources, from patients, medical personnel, and even the environment surrounding the hospital. Once established in sink drains, they can spread outwards, posing significant risks to immunocompromised patients above all,” said Gomila.
Antibiotic Resistance: A Growing Concern
Of the species found here, Klebsiella, Enterobacter, and P. aeruginosa feature among the so-called ESKAPE group of bacteria, known to thrive in hospital settings and to show frequent multi-resistance and a high potential for causing illness.
In the present study, 21% of P. aeruginosa isolates were found to be resistant to at least one class of antibiotics. Multiple Klebsiella and Enterobacter strains detected proved resistant to the third-generation antibiotic cephalosporin, but not to the carbapenems commonly used today against multidrug-resistant infections.
Worryingly, the blaVIM gene, which makes its carriers resistant even to carbapenems, was detected sporadically in a minority of P. aeruginosa strains from the two intensive care wards, the general medicine ward, and the short-stay ward.
Hospital Drains: A Hidden Reservoir of Superbugs
The authors concluded that hospital drains can serve as reservoirs for both known and emerging pathogens, some of which exhibit strong antibiotic resistance.
“Cleaning protocols are important and should be frequently applied, especially in wards that are kept separate precisely to slow the spread of potentially harmful bacteria. But to get to the bottom of the problem, it’s essential to study the source of these bacteria and their routes of transmission,” reminded first author José Laço, a PhD student in Gomila’s laboratory.
Reference: “Yearlong analysis of bacterial diversity in hospital sink drains: culturomics, antibiotic resistance and implications for infection control” by José Laço, Sergi Martorell, Maria del Carmen Gallegos and Margarita Gomila, 18 November 2024, Frontiers in Microbiology.
DOI: 10.3389/fmicb.2024.1501170
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
17 Comments
Bacteria is SUPPOSED to be washed off one’s hands and into a drain. It should not be surprising that one would find bacteria in drains.
But how often are sink basins cleaned, which bacteria from drains may climb up into and thereby contaminate those washing their hands?
BTW: Both times that I contacted Covid was in a hospital and then in a medical office!
Well only the bacterial with legs, maybe arms and possibly climbing gear.
What about ultraviolet systems, aimed directly down drains, and exposed for a period, say 15 minutes or so!? Are there any such devices out there!? And maybe sterilizing a room in the same manner. For about 30 minutes or whatever it takes. These are the only other sterilizing methods I can think of.
Our hospital used the UV devices on a regular basis. They discontinued their use, and now the rate of hospital acquired infection rate has significantly increased!
The material drains are made of makes a big difference also. It’s proven copper plumbing helps avoid spreading pathogens in drains. I suppose silver would be even better. Both silver and copper have antibiotic characteristics.
Did you read the entire article? Maybe you didn’t comprehend the medical terminology. You gave a childlike response to a subject you are not competent in. Try using a dictionary. It’s sad people are still walking around in the 1800s in ignorance.
1800s ???
I stumbled across this article and have a general question if anyone might know: Is it a requirement that bacteria such as Pseudomonas aeruginosa, Klebsiella pneumoniae, and others be reported? If so, what agencies obtain this information? Also, is it public information to find out/know what bacteria are prevalent at medical facilities? Long story short, during a US hospital stay in 2023 my mom contracted 4 of the ESKAPE bacteria but doctor’s always downplayed the significance of the bacteria. It has taken me all of 2024 to comb through 6,000 pages of medical records to find all 8 bacteria that infected her and had deadly consequences. Thank you.
What about bleach down the drains?
You read my mind.
They stopped using bleach over 30 years ago. For HEALTH AND SAFETY REASONS.!
Hospitals must do a better job at controlling infectious agents in their premises! Many are doing a below standards control!
Remove the curtains between each bed. They are disgusting
Change and rotate the cleaning agents so bacteria do not become resistant to the cleaning agents.
Be aware of biofilms and mitigate against. Not familiar with the how, I just know they can develop almost anywhere.
I like the copper or silver pipes idea.
UV sterilization should be standard!
What about bacteriophage agents?
Come on people. We can figure this out. Nobody should die or lose a limb to this. The numbers are unacceptable!
What if there was a continous water flow. Washing the bacteria down and away continously. You could use a recycle design with multiple filters to save water. Stagnant water is like a vacation resort for microbes.
And now…the Center for Disease Control has had a very significant drop in personnel. At a time when most needed. Reports such a this never reach the general public until it’s way too late. Hospital drains … drug resistant… I do not believe it takes a genius to know where those drains lead. Or how much bigger than hospital drains that this really is. Drug resistant strains are just exactly THAT. Drug/chemical resistant. Water treatment plants do not and will not have any type of defense against what the WORLD has come to know as bacteria that are resistant to any form of known defense known to man. Now I’m not a political person although I do try to stay informed. And I’m not one to go to church just because the doors open and feel myself a good Christian if I did. But I AM a spiritual individual. And I DO KNOW there’s something much bigger than ourselves. And If ever there were a time to know exactly which side of the PROVERBIAL “fence” to make damn sure on which you stand firm … that time is now.