Dr. Patrick Charles, a PhD researcher and Austin Health Infectious Diseases consultant, says that only five per cent of people admitted to hospital with community-acquired pneumonia have infections caused by organisms that can not be successfully treated with the combination of penicillin and an "atypical" antibiotic, such as doxycycline or erythromycin.
He came to this conclusion after analysing samples of blood, urine, sputum and viral swabs of the nose and throat taken from 885 patients admitted to six Australian hospitals over 28 months from 2004 to 2006.
The study revealed that most cases of pneumonia were caused by easy to treat bacteria such as the pneumococcus or Mycoplasma, or alternatively by respiratory viruses that do not require antibiotic therapy.
"The study results show that current Australian guidelines for prescribing antibiotics for pneumonia are appropriate. It shows that Australian doctors should resist the push which is occurring in some parts of the world - particularly the US - to prescribe broad spectrum antibiotics to treat essentially all possible causes,'' Dr. Charles said.
He said that the trend towards broad-spectrum antibiotics was being driven by laboratory-based studies, wherein the bacterial isolates would often come from highly selected patients with more difficult to treat disease.
He also highlighted the fact that the fear of litigation made some doctors unnecessarily opt for more aggressive treatments.
"The emergence of antibiotic-resistant bacterial pathogens is one of the biggest threats to Australian health care standards and is closely linked to the inappropriate use of antibiotics. By continuing to use more traditional antibiotics to treat most cases of pneumonia, Australian doctors can limit or delay the emergence of more resistant strains of bacteria,'' he said.
"By using the broad-spectrum antibiotics less often, we can also prolong the effective lifespan of these drugs. Furthermore, in the US, Canada and some parts of Europe, they are seeing some serious complications which appear to be related to the overuse of some classes of broad-spectrum antibiotics that are frequently used there to treat respiratory infections," he added.