A Multicenter Study of the Antimicrobial Susceptibility of Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis Isolated from Patients with Community-Acquired Lower Respiratory Tract Infections in 1999 in Portugal

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 beta-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 beta-lactamase. Resistance to penicillin, cefuroxime, erythromycin, clarithromycin, and azithromycin in S. pneumoniae and beta-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.

Antimicrobial susceptibility of Haemophilus influenzae, Haemophilus parainfluenzae and Moraxella catarrhalis isolated from adult patients with respiratory tract infections in four southern European countries

“…The rate of clarithromycin-resistance found in this study is rather low but in one study carried out in Spain, up to 22.6% of H. influenzae isolates were resistant to this antibiotic [3]. Resistance or diminished susceptibility to such drugs has also been previously reported [3,5,6,10]. Resistance to other antibiotics not tested in the present study has been reported as low for chloramphenicol (0% in Italy and Portugal and 3.6% in Spain) [2], 3.2% in Portugal and 10.6% in Greece for tetracycline [4,6] and less than 0.3% in Spain and Italy for fluoroquinolones [1,2,5].…”

“…Resistance or diminished susceptibility to such drugs has also been previously reported [3,5,6,10]. Resistance to other antibiotics not tested in the present study has been reported as low for chloramphenicol (0% in Italy and Portugal and 3.6% in Spain) [2], 3.2% in Portugal and 10.6% in Greece for tetracycline [4,6] and less than 0.3% in Spain and Italy for fluoroquinolones [1,2,5]. However resistance to cotrimoxazole is reported to be high in Spain (42.5%) [2], and low in Italy (9.3%) [2], Portugal (8.3%) [2], and Greece (5.3%) [4].…”

“…These were from 2% in Italy [2], 12.6% in Portugal [2], 28% in Greece, [4] to 31.7% in Spain [2]. However, differences within the same country are commonly found (7.9-47.9%, in Spain, and 8.1-13.8% in Portugal) [5,6]. Although we did not investigate ␤-lactamase production, the great differences in MIC values between amoxicillin (MIC 90 = 8 mg/l) and amoxicillin/clavulanate (MIC 90 = 1 mg/l) suggest a very high rate of production.…”

“…New antibiotics should also be tested because the resistance problem is reducing treatment options. As increased rates of antibiotic resistant isolates have been described in countries from the south of Europe [1][2][3][4][5][6], we developed the Antibiotic Resistant Isolates in Southern European countries (ARISE) project as a point prevalence study that looked at isolates collected over a relatively narrow period of time. At the same time cefditoren, a new cephem antibiotic [7,8] was studied and this paper shows the results obtained with H. influenzae, H. parainfluenzae and M. catarrhalis.…”

Denmark 14 -230 Clone as an Increasing Cause of Pneumococcal Infection in Portugal within a Background of Diverse Serotype 19A Lineages

“…Serotyping was performed by the standard capsular reaction test with a chessboard system (36) and specific sera (Statens Serum Institut, Copenhagen, Denmark). Etest strips (AB Biodisk, Solna, Sweden) were used to determine the MICs for penicillin, as described previously (25), and the Clinical and Laboratory Standards Institute (CLSI) recommended breakpoints (10) were used to interpret the MICs. The isolates were further characterized by determining their susceptibilities to co-trimoxazole, levofloxacin, erythromycin, clindamycin, tetracycline, and chloramphenicol by the Kirby-Bauer disk diffusion technique, according to the CLSI recommendations and interpretative criteria (10).…”