What's growing in your sink What's growing in your sink

What’s Growing in Your Sink?

By: Kelly D. Ogle, BSDH, MIOP, CMPM, CHOP®
Director of OSHA and HIPAA Services

Handwashing is a good thing—or is it?  What happens to the bacteria removed from the hands?

The Centers for Disease Control and Prevention (CDC) published on its website a study about nosocomial infections  (now called “healthcare acquired infections,” or HAIs) that were traced back to hospital sinks.

The study, also published on several media outlets, focused on a multiple drug-resistant strain of Pseudomonas aeruginosa, but several other resistant organisms were found as well. The environmental study was prompted by an unusually high incidence of these organisms and the diversity of the organisms found in patients treated at a hospital in France.

After seeing these findings, a research team in California studied possible mechanisms of the spread of these organisms and theorized that water from the faucet flows straight into the drain, allowing splashes that could contaminate the sink and any surrounding area, including hands (during handwashing) and mouths (while brushing teeth). These organisms were also found in tub and shower drains from bathing or showering. Even healthcare workers washing their hands could become contaminated, passing the infections to yet other patients.

The organisms had colonized in the elbow (U-shaped trap that holds water) of the drain pipes, making disinfection nearly impossible. The hospital tried taking the pipes apart, scrubbing them and cleaning them with bleach.  After many days of spraying the insides of the pipes with bleach, the drug-resistant pathogens finally were defeated.

Source: Amoureux L, Riedweg K, Chapuis A, Bador J, Siebor E, Péchinot A, et al. Nosocomial Infections with IMP-19−Producing Pseudomonas aeruginosa Linked to Contaminated Sinks, France. Emerg Infect Dis. 2017;23(2):304-307. https://dx.doi.org/10.3201/eid2302.160649

What does this mean to you?

Most obviously, the sinks in your practices could be similarly contaminated, though probably not with these hardy drug-resistant organisms. The recommended method for preventing the bacterial colonization of sinks is daily scrubbing and flushing with bleach.

This is also important in home sinks, both kitchen sinks and bathroom sinks. One study revealed that the bathroom sink in a home can have up to 500,000 bacteria per square inch—so scrub and bleach frequently!  Especially when someone living or visiting there has been ill.

What types of bacteria are found in sinks? 
  • Salmonella, which causes typhoid diseases and gastrointestinal infections
  • Campylobacter jejuni, which causes foodborne and GI illnesses
  • Escherichia coli, which is ubiquitous in the environment and only problematic if pathogenic strains are present
  • Stahylococcus aureus, known to cause skin and soft tissue infections as well as gastrointestinal illnesses
What are the most germ-ridden places in your home and what can you do about it?
  1. The kitchen sink is the worst offender (scrub and bleach!), with the kitchen sponge being a perfect growth and transport media. Disinfect that sponge daily with bleach or place it, wet, in the microwave for 1 minute (or replace it).
  2. Your toothbrush holds up to 100 million germs, but many came from your own mouth and are probably harmless. Rinse your toothbrush well after each use and dry thoroughly.
  3. TV remotes and computer keyboards should be wiped with a disinfecting wipe frequently.
  4. Ever noticed a pink or red slimy substance forming in your tub, sink, shower or toilet bowl? That’s Serratia marcescens, which may cause respiratory, wound, and urinary tract infections in susceptible individuals. Scrub with cleaner and then soak with bleach, rinsing well after 20 minutes.