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Explainer: What Is a Healthcare-Associated Infection?

Explainer: What Is a Healthcare-Associated Infection?

This is the first of two explainers associated with Priyanka Pulla’s report on healthcare-associated infections and accreditation issues.

When patients contract an infection after being admitted to a hospital, they are said to have a healthcare-associated infection (HAI). The most common microbes that cause HAIs in India today are gram-negative bacteria – a class of bacteria that have a protective outer cell membrane that helps resist several antibiotics. Gram-negative bacteria often encountered in Indian hospitals include Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii.

Gram-positive bacteria, like Staphylococcus aureus, are more common in the US. Because they lack the outer membranes, they are less intrinsically able to resist antibiotics, although they can also develop resistance quickly after being exposed to antibiotics. Some studies suggest the predominance of gram-negative bacteria in warm countries like India compared to gram-positive ones in temperate climes, might be due to weather differences.

How do HAIs spread?

Hospital bugs can spread from patient to patient in a thousand insidious ways. For one, devices like urinary catheters, which breach the body’s natural barriers (like the skin or mucous membranes), can transport bacteria from a nurse’s hands to the patient’s urinary tract. There, the bugs can trigger a catheter-associated urinary-tract infection, a common HAI.

Often, HAIs can emerge from within a sick patient’s own body. For example, a ventilator’s breathing tube could transfer bacteria from a person’s mouth into their lungs. The heavy doses of antibiotics could also disrupt a patient’s microbiome, leading to pathogens like Clostridium difficile multiplying and causing an infection. Some studies suggest that a majority of HAIs come from sources within the body and that medical devices and antibiotic treatment simply heighten the risk of overt infection.

A third way that HAI bugs spread is by lingering on hospital surfaces, even inside bottles of medicine. In 2018, Chennai’s Apollo Hospital reported that patients in one of its critical-care units had contracted infections from the bacterium Burkholderia cepacia, likely from a batch of ultrasound gel.

To find the source of the infection, Apollo’s infection-control team tested surfaces in the critical care unit, like patient bed-railing and ECG machines. The only place they could find the bug was inside bottles of opened and unopened ultrasound gel, suggesting the gel had been contaminated during manufacturing.

“When the hospital did the ultrasounds, the patients became colonised [with B. cepacia]. From there, the bug got into the central line,” V. Ramasubramanian, a member of Apollo’s infection-control team, said. The hospital subsequently switched to a sterile ultrasound-gel product and after which there were no more B. cepacia cases.

Drug manufacturers are not always the source of contamination. Usually the hospitals’ own infection-control practices are at fault. Careless acts like reusing saline bottles for cleaning the intravenous lines of multiple patients can introduce hospital bugs into the bottles. This is why CDC guidelines for infection-control recommend against such reuse. But healthcare workers still do it.

After an outbreak of B. cepacia in the surgical ICU of Srinagar’s Sher-i-Kashmir Institute of Sciences, an investigation revealed multiple infection-control lapses, including the reuse of saline bottles to flush IV lines. This bottle had become contaminated with B. cepacia, and could have helped the bug spread to other patients inside the ICU.

How do hospitals control HAIs?

Keeping such microbes in check requires hospitals to have strong infection-control protocols, many of which have been shown to cut HAI rates. Chief among them is hand hygiene, or washing or sanitising one’s hands at critical times. Merlin Moni, a clinician and a member of the infection-control team at the Amrita Institute of Medical Sciences, Kochi, said doctors sometimes have to sanitise their hands up to 30 times a day.

Motivating healthcare personnel to wash hands and use alcoholic hand-rubs requires the hospital to repeatedly train them as well as stock hand-sanitisers and soap at critical stations. For example, the Sir Gangaram Hospital in Delhi has a policy of placing alcoholic hand-rubs next to every bed in patient wards.

Availability matters. The WHO guidelines state that a big reason why people don’t clean their hands is because there is no soap available. But other factors matter as well. For example, healthcare workers avoid soaps that dry the hands too much. So the WHO recommends hospitals pick a product that is gentle on the skin as well as distribute moisturisers to workers.

There’s more than hand-hygiene, of course, including many precautions that hospitals must take to keep HAIs at bay. The ICMR’s infection control guidelines for example, lists 14 chapters of such precautions. Among them, doctors and nurses must use personal protective equipment such as gloves and masks when interacting with infectious patients. The hospital must ensure beds are 1-2 meters apart. Frequently touched environmental surfaces, like the railing of a patient’s bed and medicine supply carts, must be routinely cleaned. Healthcare workers must be screened frequently to check if they’re carrying dangerous bugs like the methicillin-resistant Staphylococcus aureus, so they don’t give it patients.

A particularly important aspect of avoiding infections from invasive devices is the implementation of ‘care bundles’ — a set of five or five practices that healthcare workers follow while hooking someone up to a ventilator, central line or other device that penetrate the body. Care bundles for preventing ventilator-associated pneumonia, for instance, require patients to lie down at a 45º angle, if possible, preventing the patient from aspirating pathogens and minimising the chance of pneumonia.

Reporting for this article was funded by the European Journalism Center (EJC) through its Global Health Fellowship Program.

Priyanka Pulla is a science writer.

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