Abstract
A nationwide multicenter study (including 25 laboratories) of the antimicrobial susceptibility of bacterial pathogens commonly associated with community-acquired lower respiratory tract infections (LRTI),
with testing undertaken in a central laboratory, was conducted in Portugal in 1999. Antimicrobial resistance in
Haemophilus influenzae
has not increased in the last decade. Of the 498 isolates tested,
12.4% produced β-lactamase and >95% were susceptible to all antimicrobials except ampicillin. In contrast, there was a rapid increase of resistance in
Streptococcus pneumoniae
. Of the 312
isolates tested, 24.7% exhibited decreased susceptibility to penicillin (13.5% showed low-level and 11.2% high-level resistance), 13.8% were resistant to erythromycin, clarithromycin and azithromycin, and
13.6% to cefuroxime and to tetracycline. Of the 38
Moraxella catarrhalis
tested, 81.6% produced β-lactamase. Resistance to penicillin, cefuroxime, erythromycin, clarithromycin, and azithromycin
in
S. pneumoniae
and β-lactamase production in
H. influenzae
were significantly higher in pediatric patients than in adults. Overall, amoxycillin/clavulanate was the most active antimicrobial
agent
in vitro
against
H. influenzae
,
S. pneumoniae
, and
M. catarrhalis
isolated from patients with community-acquired LRTI in Portugal.