MONTREAL — European and North American experts continue to disagree about the management of mild community-acquired pneumonia, with the debate centering on the overuse of wide-spectrum antibiotics.
New guidelines released jointly by the Infectious Diseases Society of America and the American Thoracic Society recommend that empiric treatment of mild CAP in previously healthy individuals should include a macrolide to cover not only the most common pathogen (Streptococcus pneumoniae) but also atypical pathogens (Clin. Infect. Dis. 2007;44 [suppl. 2]:S29–72). In contrast, European guidelines do not target atypical pathogens, recommending β-lactams as the only treatment of choice (Eur. Respir. J. 2005;26:1138–80).
“If and when we get rapid diagnostic tests [to identify specific pathogens], this [will be] a moot point, but right now all we can do is base our treatment decisions on an empiric approach,” Dr. Thomas File, professor of internal medicine and head of infectious diseases at Northeastern Ohio Universities, Rootstown, said at an international conference on community-acquired pneumonia.
European and North American experts agree that roughly 40% of mild CAP may be caused by atypical pathogens, but Europeans are prepared to ignore these pathogens in their choice of empiric therapy because these infections are usually self-resolving, said Dr. Jean-Claude Pechère, a professor of medicine at the University of Geneva.
“In this way, we can avoid a lot of antibiotic overuse,” he said in an interview. “In the context of increasing resistance, it's a big public health issue.”
Although many atypical CAP infections are self-resolving, the evidence shows that antibiotics can speed recovery, Dr. File said at the conference, sponsored by the International Society of Chemotherapy. “People get sick, and people are off work or school. If, by treating them, we can help them resolve their illness quicker, then we think it's worthwhile,” he said in an interview.
However, new evidence suggests coverage of atypical pathogens also may improve mortality, at least in hospitalized patients, Dr. File said. An analysis of more than 2,000 patients found that, compared with those treated only for typical pathogens, those treated with atypical coverage had decreased time to clinical stability (3.2 vs. 3.7 days), decreased length of hospital stay (6.1 vs. 7.1 days), decreased total mortality (7.0% vs. 11.1%), and decreased CAP-related mortality (3.8% vs. 6.4%) (Am. J. Respir. Crit. Care Med. 2007; doi:10.1164/rccm.200603–350OC).
“The significant global presence of atypical pathogens and the better outcomes associated with antimicrobial regimens with atypical coverage support empiric therapy for all hospitalized patients with CAP with a regimen that covers atypical pathogens,” the authors concluded.
The atypical pathogens responsible for mild CAP include Mycoplasma pneumoniae and Chlamydia pneumoniae. Dr. Pechère and Dr. File agreed that the third atypical pathogen, Legionella, without question should be treated immediately and aggressively, because it is associated with a high mortality rate.
According to Dr. Pechère, the North American guidelines “promote overuse” of antibiotics. But Dr. File sees it differently. The IDSA/ATS guidelines underscore the necessity of a chest x-ray in the diagnosis of CAP, thus ensuring that only radiographically confirmed cases are treated. “If the decision is based on a positive chest x-ray, then we feel all those patients warrant antimicrobial therapy—because it's unlikely that they've got viral bronchitis if they've got true infiltrate.”
But this is not the scenario in Europe, he said, where x-ray confirmation is not required for the diagnosis of CAP. The overuse of antibiotics in respiratory infection is not from overtreating pneumonia, it's from overtreating viral infections, which are much more common.
'Right now all we can do is base our treatment decisions on an empiric approach.' DR. FILE