Tamiflu resistant influenza reported in Australia

Over two dozen cases of H1N1 swine flu that are resistant to Tamiflu have been reported in Australia in the largest outbreak of the drug-evasive influenza strain to date.
Viruses from 25 out of 184 patients in the Newcastle area of eastern Australia infected with the pandemic strain had a genetic mutation that reduces the potency of Tamiflu, Bloomberg reports. The cases, first reported in May, raise concern that the resistant strain may spread, leaving doctors unable to use their preferred treatment for influenza.
The report of the drug-resistant infection was distributed by the International Society for Infectious Diseases' ProMED-mail program. According to the World Health Organization's Collaborating Center for Influenza in Melbourne, GlaxoSmithKline Plc's Relenza drug is effective against the mutant strain.
“As long as it’s isolated to Newcastle and that region, it’s not so much of a problem,” Ian Barr, the center’s deputy director, said in a telephone interview, Bloomberg reports. “If it spreads further, it might be a concern. Fortunately, we’re heading toward the end of our flu season.”
None of those infected had taken Tamiflu prior to being tested for flu. Out of 16 patients interviewed by the scientists, none had a history of immune suppression. None of the patients was admitted to an intensive care unit or died from the strain. Virological analysis and further interviews are ongoing, the scientists said.
Studies have shown that Tamiflu-resistant bugs develop sporadically in 0.4 to four percent of adults and children treated for seasonal influenza. Tamiflu and Relenza, an inhaled powder, reduce the duration and severity of flu symptoms by 24 to 30 hours of treatment begins within the first two days of illness. Both drugs work by blocking the neuraminidase protein on the surface of influenza particles that allows the virus to spread from infected cells to other cells.
Mutant H1N1 viruses evade Tamiflu through a single genetic change called the H275Y mutation, which prevents the medicine from attaching to neuraminidase and enables the pathogen to spread.
The first outbreak of cases of seasonal flu with the mutation was recorded in January 2008 in Norway, according to Bloomberg. bBy the following August ,widespread resistance was reported in 40 countries in North and South America, Africa, Asia, Australia and Europe.