ABSTRACT
Resistance of 235 Haemophilus influenzae clinical isolates from Istanbul Medical Faculty Hospital, Turkey were determined against 19 antibiotics by disc diffusion method, and minimum inhibitory concentrations (MICs) of those found resistant to ampicillin, cefuroxim, chloramphenicol and meropenem were measured using E-test. Ampicillin-resistant isolates producing beta-lactamase as demonstrated by a nitrocefin assay were analyzed for the presence of TEM-1 and ROB-1 genes by PCR. Eleven percent of the isolates were resistant to ampicillin (10 µg/ml), of which 73% were beta-lactamase positive and carried TEM-1 gene, but none were positive for ROB-1 gene. All isolates susceptible to amoxicillin-clavulanate (20/10 µg/ml), azithromycin (15 µg/ml), aztreonam (30 µg/ml), cefotaxime (30 µg/ml), ceftriaxone (30 µg/ml), ciprofloxacin (5 µg/ml), levofloxacin (5 µg/ml), and telithromycin (15 µg/ml) but 24%, 15%, 4%, 4%, 2%, 1%, 1%, 0.5%, 0.5% and 0.5% were resistant to trimethoprim-sulfamethoxazole (1.25/23.75 µg/ml), tetracycline (30 µg/ml), cefaclor (30 µg/ml), clarithromycin (15 µg/ml), cefuroxime (30 µg/ml), meropenem (10 µg/ml), chloramphenicol (30 µg/ml), ampicillin-sulbactam (10/10 µg/ml), nalidixic acid (30 µg/ml), and fosfomycin (30 µg/ml), respectively. MIC values of three cefuroxime-resistant isolates was 24, 48 and > 256 µg/ml, respectively; of two meropenem-resistant strains > 256 µg/ml; and of two chloramphenicol-susceptible isolates (by disc diffusion method) 6 µg/ml (considered as intermediate susceptible). Multiple- antibiotics resistance was detected in 15% of the strains, with resistance to 2, 3, 4, 5 and 6 antibiotics in 8.5%, 4%, 2%, 0.5% and 0.5% of the isolates, respectively. By identifying beta-lactamase-negative ampicillin-resistant H. influenzae, empirical therapy with beta-lactam/beta-lactamase inhibitor combinations and second generation cephalosporins would be inappropriate for such patients (approximately 3%). Our findings will contribute to the epidemiological and clinical data regarding H. influenzae infection in Turkey.
Subject(s)
Anti-Bacterial Agents/pharmacology , Haemophilus Infections/microbiology , Haemophilus influenzae/genetics , beta-Lactam Resistance/genetics , beta-Lactamases/genetics , Female , Haemophilus Infections/epidemiology , Haemophilus influenzae/drug effects , Haemophilus influenzae/physiology , Humans , Male , Microbial Sensitivity Tests , Polymerase Chain Reaction , TurkeyABSTRACT
BACKGROUND: We compared the in vitro activities of tigecycline with those of other agents against 97 Streptococcus pneumoniae, 140 Haemophilus influenzae and 54 Moraxella catarrhalis strains isolated in two large university hospitals in Istanbul. METHODS: For analysis, the agar dilution method was used. RESULTS: For S. pneumoniae isolates, 32% were not susceptible to penicillin (28.9% intermediate and 3.1% resistant). Cefotaxime, telithromycin, moxifloxacin and linezolid were fully active. Tigecycline had a 90% minimum inhibitory concentration (MIC(90)) of 0.12 microg/ml. For H. influenzae, 8.57% were not susceptible to ampicillin, among which 8 possessed beta-lactamase (5.7%). Four (2.87%) H. influenzae isolates with beta-lactamase-negative and ampicillin-resistant phenotype were found. All isolates were susceptible to ceftriaxone, azithromycin, ciprofloxacin, levofloxacin and moxifloxacin. MIC(90) for tigecycline was 0.5 microg/ml. Of 54 M. catarrhalis isolates, 88.9% possessed beta-lactamase. Tigecycline and fluoroquinolones were highly active (MIC(90) < or =0.12 microg/ml). CONCLUSIONS: Linezolid, telithromycin, newer fluoroquinolones and tigecycline all have excellent in vitro activities against the 3 respiratory pathogens.
Subject(s)
Anti-Bacterial Agents/pharmacology , Haemophilus influenzae/drug effects , Minocycline/analogs & derivatives , Moraxella catarrhalis/drug effects , Streptococcus pneumoniae/drug effects , Drug Resistance, Multiple, Bacterial , Haemophilus influenzae/isolation & purification , Hospitals, University , Humans , Microbial Sensitivity Tests , Minocycline/pharmacology , Moraxella catarrhalis/isolation & purification , Streptococcus pneumoniae/isolation & purification , Tigecycline , TurkeyABSTRACT
The in vitro activity of telithromycin was compared with erythromycin A, azithromycin, clarithromycin, moxifloxacin, gemifloxacin, levofloxacin, ciprofloxacin, penicillin G, ampicillin, cefuroxime and ceftriaxone against 336 consecutive strains (83 Streptococcus pneumoniae, 168 Haemophilus influenzae and 85 Moraxella catarrhalis) isolated from patients with community-acquired respiratory tract infections. Telithromycin (MIC(90), 0.008 mg/l) was the most active drug against S. pneumoniae. Telithromycin was also highly active against M. catarrhalis (MIC(90), 0.06 mg/l), but less active against H. influenzae (MIC(90), 4 mg/l).
