Comparative in-vitro activity of levofloxacin against isolates of bacteria from adult patients with community-acquired lower respiratory tract infections

Abstract

This study was conducted to evaluate the activity of levofloxacin in comparison with a range of antibacterial agents against recent isolates obtained consecutively from patients with community-acquired pneumonia (CAP) or acute exacerbation of chronic bronchitis (AECB) during the period 1995 to 1996. Susceptibility testing was carried out by either microdilution or the Etest, and interpreted according to NCCLS breakpoints. The activity of levofloxacin was compared with that of amoxycillin, amoxycillin-clavulanate, cefuroxime, cefixime, erythromycin, roxithromycin, clarithromycin, azithromycin, ofloxacin and ciprofloxacin. Clinically significant numbers of bacteria were recovered from 31 CAP and 94 AECB specimens. The predominant bacterial species in the CAP specimens were Streptococcus pneumoniae (21 isolates) and Haemophilus influenzae (four isolates). The AECB isolates mainly consisted of S. pneumoniae (38%), Moraxella catarrhalis (26%), H. influenzae (19%) and Pseudomonas aeruginosa (10%). The overall percentage susceptible of the isolates for each antibiotic was: amoxycillin, 64%; amoxycillin-clavulanate, 89%; cefuroxime, 87%; cefixime, 78%; erythromycin, 85%; roxithromycin, 87%; clarithromycin, 87%; azithromycin, 85%; ofloxacin, 95%; ciprofloxacin, 95%; and levofloxacin, 97%. The activities of levofloxacin and the other agents were also compared against 40 S. pneumoniae isolates, of which 20 were penicillin-non-susceptible, recovered from CAP and AECB specimens during the period 1994 to 1996. These strains were all susceptible to levofloxacin, but only 50% were susceptible to ciprofloxacin and 80% to ofloxacin. Twenty M. catarrhalis, 20 H. influenzae and 20 methicillin-susceptible S. aureus isolates were also all susceptible to levofloxacin. Furthermore, 20 community-acquired P. aeruginosa isolates showed similar percentage susceptible rates to levofloxacin and ciprofloxacin. These in-vitro results suggest that levofloxacin may be useful in the treatment of community-acquired lower respiratory tract infections.

Comparative in vitro Activity of Levofloxacin and Ciprofloxacin against Bacterial Isolates from Neutropenic Patients

“…In contrast to others [16,18,21,22], we did notice a reduced susceptibility to levofloxacin and ciprofloxacin of P. aeruginosa, still an important and frequent pathogen in neutropenic patients. Further, a partial (70%) cross-resistance occurred in P. aeruginosa isolates, thus confirming the recent finding by Segatore et al [21] who assessed the activity of levofloxacin against P. aeruginosa isolated from intensive care units, and haematology and oncology wards.…”

Bacterial Pneumonia at King Abdulaziz University Hospital: A Comparison between Hospital- and Community-Acquired

“…The American Thoracic Society guidelines stress the use of empirical treatment as pathogen identification can be difficult [1]. We found that ampicillin, co-amoxiclav, fluoroquinolone, secondgeneration cephalosporin, erythromycin and tetracycline can be used empirically in the treatment of CAP, while aminoglycosides and imipenem can be used in HAP, a finding in agreement with the recommendations of others [1,2,15,[22][23][24][25][26][27][28]. Mortality from pneumonia (both CAP and HAP) has been reported to range from 10 to 70% [13,[29][30][31], with a better prognosis for CAP than HAP [32], a finding similar to our own.…”

“…Mycoplasma, Legionella sp., Chlamydia pneumoniae) can account for 30% of the cases of CAP [2,10]. Other pathogens include H. influenzae, Staphylococcus aureus, and M. catarrhalis [11][12][13][14][15]. Our study showed that S. pneumoniae was isolated in only 3% of the cases of CAP while H. influenzae was the commonest Number and percent (in parentheses) are given.…”

Fluoroquinolones for Respiratory Infections

“…Levofloxacin provides a useful empiric alternative to ciprofloxacin for patients in whom the role of P aeruginosa is unclear and for whom broader coverage for atypical and Grampositive pathogens also is desired. 33 Newer fluoroquinolones lose activity against Pseudomonas but increase activity against atypical, Gram-positive, and anaerobic pathogens. Unfortunately, the treatment of acute purulent exacerbations of chronic bronchitis with a fluoroquinolone can induce resistant isolates.…”