David Brill
Rising levels of drug resistance among Acinetobacter Baumannii are causing serious concern among infectious disease experts, who are calling for urgent international attention to the issue.
The bug is particularly prevalent in hospitals in Southeast Asia, with Taiwan and Korea seemingly the worst affected.
The rapidly dwindling number of treatment options could soon herald the dawn of the “post-antibiotic era,” according to a specialist from Singapore, where extensively drug-resistant strains have already been reported.
A. Baumannii resistance rates are increasing globally, with around half of strains presently thought to be resistant to at least one antibiotic. Nearly 20 percent of strains are resistant to all but one or two agents.
Reports have already emerged of pandrug resistant strains, which – although rare at present – will beome increasingly common if the problem is not addressed, said Professor Matthew Falagas, an international expert who published a recent high-profile review calling for more research into treatment options. [Lancet Infect Dis 2008 Dec;8(12):751-62]
“We should be worried because we have never heard before of bugs which affect humans where we do not have an antibiotic to provide,” he told Medical Tribune.
“The issue of pan-drug resistance needs international attention. Public health organizations and local infection controls at the country level should disseminate guidelines on this issue,” he said, adding that in some hospitals the significance of the bug is already on a par with methicillin-resistant S. Aureus (MRSA).
A. Baumannii mainly affects seriously ill patients in intensive care units and burn wards. Although less common than other hospital-based infections, the bug can cause significant morbidity and mortality, placing a heavy drain upon hospital resources through repeated hospitalizations and increased lengths of stay.
A Singapore study found that 69 percent of A. Baumannii strains in one intensive care unit were resistant to carbapenem. Nearly 20 percent of isolates from all the nation’s hospitals were resistant to everything except the polymixins, which can cause significant toxicity to the brain and kidneys. [Emerg Infect Dis 2007 Dec;13(12):1944-7]
“Its ability to acquire resistance is a big concern because there aren’t going to be many treatment options available,” said Dr. Tan Thuan Tong, an infectious diseases consultant at Singapore General Hospital.
“We foresee a time when you get strains that are not treatable and you just try your luck with various combinations that might act in a synergistic manner,” he said, adding that such a scenario could arise in Singapore within the next 5 years.
Around 30 to 40 percent of patients who get a multidrug-resistant A. Baumannii bloodstream infection may die, according to Tan, but he added that the directly attributable mortality is not clear-cut since patients are often critically ill for other reasons.
Falagas, meanwhile, called on hospitals worldwide to decrease the usage of antibiotics and promote stricter infection prevention and control measures, particularly with regard to hand hygiene. He added that research is now ongoing to find new antibiotics for Gram-negative bacteria, but said that the process has been too slow getting started.
“The scientific community and the pharmaceutical companies have focused attention on Gram-positives without understanding the significance of Gram-negatives as healthcare-associated infections, and especially A. Baumannii,” said Falagas, who is director of the Alfa Institute of Biomedical Sciences in Athens, Greece, and an adjunct associate professor at Tufts University
School of Medicine, Boston, US.
Singapore has already begun to acknowledge the growing problem of antimicrobial resistance, with a group of experts publishing a recent position paper advocating stricter controls on the use of antibiotics. [Singapore Med J 2008 Oct;49(10):749-55]
“In the 18th and 19th century, there were no antibiotics and treatment was with drainage of pus, amputation and other surgical approaches. If you have infections with these untreatable bugs, then you are back to the days when you can’t do anything,” added Tan.
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