established by various professional societies throughout the world.
Although recommendations on the approach to treatment and the use of
antimicrobials may vary, these guidelines aim to standardize care to ensure
patients receive the most appropriate therapy according to local health
practices, epidemiology and bacterial susceptibility patterns. The etiology of
CAP is, therefore, a crucial facet to be considered in the development of such
guidelines.
IDENTIFICATION OF LIKELY PATHOGENS
Professor File looked at the most common etiologies according to the severity
of CAP in North America . Three etiologic studies, conducted in the
United States, Japan and Spain, showed S pneumoniae to be the predominant
causative agent in patients requiring hospitalization. The atypical pathogens
were also significant in these studies.
THE IMPORTANCE OF RESISTANCE PATTERNS
Another important factor in the development of CAP guidelines is increasing
penicillin resistance, particularly of S pneumoniae. Penicillin-resistant S
pneumoniae may also be resistant to other antibiotics, most commonly
cephalosporins and macrolides
ANTIMICROBIAL THERAPY FOR CAP
Initial treatment of CAP is invariably empiric. Guidelines should, therefore,
advocate the use of those antimicrobials that provide coverage of both the
most likely pathogens and resistant strains.
Advantages of the fluoroquinolones
The newer fluoroquinolones, with enhanced antipneumococcal activity, are
useful agents in the treatment of pneumonia. These agents have rapid
bactericidal activity against key CAP pathogens. Levofloxacin is currently the
only fluoroquinolone approved for use against penicillin-resistant S
pneumoniae.
The newer fluoroquinolones also penetrate well into respiratory tissues,
providing coverage of extracellular and intracellular pathogens.
THE APPROACH TO TREATMENT
The 2 fundamental treatment principles of most CAP guidelines are to treat
early and to cover likely pathogens.
Practice guidelines usually categorize all CAP patients based on an
assessment of site of therapy, the presence of comorbidity and modifying
factors (eg, risk factors for drug-resistant S pneumoniae, especially in the
elderly and those recently treated with antimicrobials).
Outpatient CAP
For outpatient treatment, a distinction is made between "simple"
and "complex" CAP. Simple CAP patients have no cardiopulmonary disease and
no risk factors for drug-resistant S pneumoniae. In these patients, the IDSA
and ATS guidelines recommend a macrolide or doxycycline.
In outpatients with more complex CAP, that is, with cardiopulmonary disease
or risk factors for drug-resistant S pneumoniae (ie, recent antimicrobial
therapy, recent hospitalization, or attendance at a day-care center), these
guidelines suggest therapy with:
● A ß-lactam combined with a macrolide or doxycycline; OR
● An antipneumococcal fluoro-quinolone alone.
The Canadian and ATS guidelines endorse the use of a macrolide or
doxycycline in uncomplicated outpatient CAP. Japanese guidelines recommend
the use of a ß-lactam for bacterial pneumonia and a macrolide or tetracycline
for atypical pneumonia.
General-ward CAP
Practice guidelines from North America are quite similar in their
recommendations for the empiric hospital treatment of CAP. One of 2 regimens
is suggested:
● an intravenous ß-lactam (usually a third-generation cephalosporin, such
as ceftriaxone or cefotaxime) with a macrolide; OR
● an intravenous antipneumococcal fluoroquinolone alone.
The Canadian guidelines, however, recommend a fluoroquinolone as first
line. The ATS guidelines also list monotherapy with intravenous azithromycin
as an option for very low-risk patients. In Asia, fluoroquinolones are endorsed
in Japan for patients without modifying factors, and in Singapore, Thailand and
Taiwan as an alternative therapy.
기사요지
노스이스턴의대 토마스 필레 교수가 `아시아지역 원외폐렴(CAP) 치료지침 회의`에 참석, 발표
한 내용. `CAP 치료에 있어 Fluoroquinolone계 항생제의 역할`을 주내용으로 하고 있다.
심폐질환이나 약물내성 폐렴연쇄상구균 위험인자(항생제 치료·입원)를 갖고 있는 CAP 외래환
자의 경우, β-lactam계와 macrolide 및 doxycycline계 항생제의 병용 또는
antipneumococcal fluoro-quinolone계 항생제 단일요법이 권고된다.
북미 임상지침도 CAP의 병원치료에 있어 정맥투여 β-lactam계(ceftriaxone·cefotaxime
와 같은 3세대 cephalosporin)와 macrolide계의 병용 또는 정맥투여 antipneumococcal
fluoro-quinolone계의 단일요법을 권고하고 있다. 반면, 캐나다 지침은 fluoroquinolone
계 항생제를 1차선택제로 강조하기도 한다.
정리·이상돈 기자 sdlee@kimsonline.co.kr