Inappropriate use of antibiotics and C. diff: what is the connection?

Antimicrobial resistance (AMR) is a natural phenomenon occurring when microorganisms – such as viruses, bacteria, fungi, and parasites – become resistant to the antimicrobial medicines designed to fight them. In other words, these medicines become less and less effective or totally ineffective in treating the infections caused by these resistant microorganisms. That’s why AMR is considered a growing public health issue.

As we know, the misuse and overuse of antimicrobials in humans, animals and plants are among the major contributors to the development of AMR in microorganisms. For instance, let’s consider antibiotics, medicines used to treat infections caused by bacteria. The inappropriate use of antibiotics may contribute to the development of resistant bacteria and their spread in patients within and across hospitals, countries, and globally.

But there is more. Do you know that the incorrect use of antibiotics can raise the risk of Clostridioides difficile infection? Have you ever heard about that?

Its name sounds like a tongue-twister, but this microorganism is not at all friendly, believe me. As a matter of fact, Clostridioides difficile (also named C. diff) is the most common cause of diarrhoea in hospitalised patients and is one of the most important microorganisms related to healthcare-associated infections.

Please, let me introduce you to this bug.

C. diff is a rod-shaped bacterium that is rarely found in the intestine of healthy adults. It has got the ability to form spores by surrounding itself with a very strong structure. It is this sort of a “shell” that enables C. diff to survive in harsh environmental conditions.

It is transmitted through the faecal-oral route. For example, in healthcare facilities C. diff can be acquired through the ingestion of spores contaminating the hands of other patients or healthcare workers, or from environmental surfaces. These swallowed spores survive the acid environment of the stomach, and then germinate in the intestine (in plain words, it means that C. diff bacteria come out of their “shells” and become active). Here, they can produce toxins (called toxin A and toxin B), which are responsible for the clinical manifestations of the infection.

Symptoms and signs may vary, from diarrhoea to fulminant sepsis with toxic megacolon, a severe condition characterised by high mortality.

There are several risk factors for C. diff infection.

The use – and clearly misuse and overuse, as well – of antibiotics is one of the risk factors. Indeed, as observed by several studies, the risk of C. diff infection increases when the duration of the antibiotic therapy exceeds 10 days. Moreover, the risk of infection increases up to 6 times during and in the month following antibiotic therapy. Nearly all antibiotics have been associated with C. diff infection; however, clindamycin, penicillins, third-generation cephalosporins and fluoroquinolones pose the greatest risk.

Now, you might be wondering: how does it happen? And why?

In our intestine both “good” and “bad” bacteria live together in a balance for protecting our body from infections and maintaining health. In normal conditions, “good” bacteria help to keep other bacteria, such as C. diff, in check. The use of antibiotics inevitably changes the normal intestinal flora by upsetting this delicate balance between microorganisms. This alteration may create favourable conditions for the proliferation of C. diff bacteria which finally can start producing bad toxins responsible for infection. That’s the problem.

In order to prevent and stop C. diff some basic measures must be promptly implemented.

Hand hygiene with soap and water is the golden rule. Indeed, the transmission of spores occurs mainly through contaminated hands. This is the cornerstone of prevention and control of all healthcare-associated infections, and especially for C. diff infection. Indeed, alcohol-based hand disinfectants are not effective against C. diff spores.

Moreover, in healthcare facilities patients with established (or even suspected) C. diff infection must undergo contact isolation precautions promptly. These measures must be followed by visitors and healthcare workers before entering and after leaving the patient’s room in order to prevent spores from spreading, thus reducing transmission between patients and environmental contamination.

Then, do not forget adequate environmental disinfection. Preventing C. diff infection in hospitals is a challenge because spores can survive on surfaces for months, and thorough cleaning and disinfection are necessary to remove them from the environment (for example, on the bed, floor, sink and light switches). Disinfection with sodium hypochlorite solutions is generally recommended in areas of healthcare facilities contaminated with C. diff.

The last but not the least, the appropriate use of antibiotics play an essential role in preventing C. diff infection, for the reasons we mentioned earlier.

In conclusion, we have learnt that the judicious use of antibiotics is crucial not only to counteract the emergence and spread of bacterial AMR.

Using these essential and life-saving medicines responsibly is also essential to reduce the risk of C. diff infection. Only take antibiotics when prescribed for you by your doctor, and always follow your doctor’s advice and instructions when taking antibiotics. Don’t forget it.