Antibiotic resistant bugs brew trouble

Sanjeet Bagcchi

doi:10.1038/nindia.2011.103 Published online 13 July 2011

Indiscriminate use of antibiotics in hospitals has resulted in serious drug resistance among a group of bacteria responsible for hospital-associated infections globally, a new study has found.

The study analysed data over 10 years (1999 to 2008) to determine the trend between drug resistance in bacteria and antibiotic consumption in patients admitted to hospitals. Researchers Chand Wattal and colleagues from New Delhi-based Sir Ganga Ram Hospital concluded that emergence of multidrug-resistant bacteria, such as Pseudomonas aeruginosa and Acinetobacter baumannii could be associated with the heavy use of antibiotics.

The researchers began by selecting these these two groups of bacteria considering the global threat they pose in hospital-acquired infections.

"These two bacteria stand a better chance of causing hospital associated infection since they predominantly belong to the environment where they can stay for a long period of time," Wattal says. If the hospital's disinfection policy is not in place, these organisms can jump on to patients via healthcare workers," he explains.

The researchers studied 69010 blood culture samples from hospitalised patients. From these, they analysed as many as 771 isolates of P. aeruginosa and 754 of A. baumannii. They found an overall increasing trend of antibiotic consumption in the hospitalised patients. A. baumannii showed resistance against three antibacterial drugs — fluoroquinolones, aminoglycosides, and carbapenems — and P. aeruginosa showed resistance against aminoglycosides group of antibiotics. Particularly for A. baumannii, heavy use of carbapenems was associated with the development of significant drug resistance, the researchers found.

"Our study has brought to the fore the significance of creating a database over a period of time to understand the evolution of antimicrobial resistance in a particular healthcare setting," says Wattal. "Since antibiotic resistance in microbes is a natural and evolving process, it is necessary to watch the trends of the development of resistance along the consumption of antibiotics in a geographical setting," he says.

However, indiscriminate use of antibiotics could be one of the factors, but not the only factor in sustaining drug resistance in bacteria, Wattal says. "In the absence of antibiotic policy in most Indian hospitals, inappropriate use of antibiotics is practiced, more so because of the lack of infectious disease specialists or medical microbiologists not practicing clinical microbiology in the country," he continues.

Swapan Jana, Secretary of a Kolkata-based Non-Governmental Organization, Society for Social Pharmacology, says these findings imply that doctors should not only stay alert regarding hospital-associated infections, they should also be cautious regarding the overuse and misuse of antibacterial drugs.

Jana suggests that in order to protect patients from the overuse and misuse of antibiotics, hospitals should enforce an antibiotic policy and establish active infection control committees.

"High end antibiotics such as carbapenems should be prescribed after approval from a medical microbiologist or infectious diseases specialist," Wattal recommends. "Also, the purchase of high end antibiotics over the counter should be restricted," he adds.


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