Moxifloxacin vs ampicillin/sulbactam in aspiration pneumonia and primary lung abscess

BACKGROUND: Aspiration pneumonia (AP) and primary lung abscess (PLA), are diseases following aspiration of infectious material from the oropharynx or stomach. An antibiotic therapy, also covering anaerobic pathogens, is the treatment of choice. In this study we compared moxifloxacin (MXF) and ampicillin/sulbactam (AMP/SUL) concerning efficacy and safety in the treatment of AP and PLA. METHODS: Patients with pulmonary infections following aspiration were included in a prospective, open-label, randomized, multicenter trial. Sequential antibiotic therapy with MXF or AMP/SUL was administered until complete radiologic and clinical resolution. RESULTS: A total of 139 patients with AP and PLA were included, 96 were evaluable for efficacy (EE, 48 patients in each treatment group). The overall clinical response rates in both groups were numerically identical (66.7%). MXF and AMP/SUL were both well tolerated, even after long-term administration [median duration of treatment (range) in days MXF versus AMP/SUL: AP 11 (4-45) vs 9 (3-25), PLA 30.5 (7-158) vs 35 (6-90)]. CONCLUSION: In the treatment of aspiration-associated pulmonary infections moxifloxacin appears to be clinically as effective and as safe as ampicillin/sulbactam; but, however, having the additional benefit of a more convenient (400 mg qd) treatment.

Antibacterial activity of moxifloxacin on bacteria associated with periodontitis within a biofilm

The activity of moxifloxacin was compared with ofloxacin and doxycycline against bacteria associated with periodontitis within a biofilm (single strain and mixed population) in vitro. Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of moxifloxacin, ofloxacin and doxycyline were determined against single strains and mixed populations in a planktonic state. Single-species biofilms of two Porphyromonas gingivalis and two Aggregatibacter actinomycetemcomitans strains and a multi-species biofilm consisting of 12 species were formed for 3 days. The minimal biofilm eradication concentrations (MBECs) were determined after exposing the biofilms to the antibacterials (0.002 - 512 µg ml-1) for 18 h, addition of nutrient broth for 3 days and subsequent subcultivation. Photographs were taken by using confocal laser scanning microscopy and scanning electron microscopy. The MICs and MBCs did not differ between ofloxacin and moxifloxacin against A. actinomycetemcomitans, moxifloxacin was more active than the other tested antibacterials against anaerobes and the mixed population. The single-species biofilms were eradicated by moderate concentrations of the antibacterials, the lowest MBECs were always found for moxifloxacin (2-8 µg ml-1). MBECs against the multi-species biofilms were 128 µg ml-1, >512 µg ml-1 and >512 µg ml-1 for moxifloxacin, ofloxacin and doxycycline, respectively. In summary, moxifloxacin in a topical formulation may have potential as an adjunct to mechanical removal of the biofilms.

Treatment failure in pneumonia: Impact of antibiotic treatment and cost analysis

The aim of this study was to investigate treatment failure (TF) in hospitalised community-acquired pneumonia (CAP) patients with regard to initial antibiotic treatment and economic impact. CAP patients were included in two open, prospective multicentre studies assessing the direct costs for in-patient treatment. Patients received treatment either with moxifloxacin (MFX) or a nonstandardised antibiotic therapy. Any change in antibiotic therapy after >72 h of treatment to a broadened antibiotic spectrum was considered as TF. Overall, 1,236 patients (mean ± SD age 69.6 ± 16.8 yrs, 691 (55.9%) male) were included. TF occurred in 197 (15.9%) subjects and led to longer hospital stay (15.4 ± 7.3 days versus 9.8 ± 4.2 days; p < 0.001) and increased median treatment costs (€2,206 versus €1,284; p<0.001). 596 (48.2%) patients received MFX and witnessed less TF (10.9% versus 20.6%; p < 0.001). After controlling for confounders in multivariate analysis, adjusted risk of TF was clearly reduced in MFX as compared with β-lactam monotherapy (adjusted OR for MFX 0.43, 95% CI 0.27-0.68) and was more comparable with a β-lactam plus macrolide combination (BLM) (OR 0.68, 95% CI 0.38-1.21). In hospitalised CAP, TF is frequent and leads to prolonged hospital stay and increased treatment costs. Initial treatment with MFX or BLM is a possible strategy to prevent TF, and may thus reduce treatment costs.

T cell-mediated hypersensitivity to quinolones: mechanisms and cross-reactivity

BACKGROUND: Quinolones are widely used, broad spectrum antibiotics that can induce immediate- and delayed-type hypersensitivity reactions, presumably either IgE or T cell mediated, in about 2-3% of treated patients. OBJECTIVE: To better understand how T cells interact with quinolones, we analysed six patients with delayed hypersensitivity reactions to ciprofloxacin (CPFX), norfloxacin (NRFX) or moxifloxacin (MXFX). METHODS: We confirmed the involvement of T cells in vivo by patch test and in vitro by means of the lymphocyte proliferation test (LTT). The nature of the drug-T cell interaction as well as the cross-reactivity with other quinolones were investigated through the generation and analysis (flow cytometry and proliferation assays) of quinolone-specific T cell clones (TCC). RESULTS: The LTT confirmed the involvement of T cells because peripheral blood mononuclear cells (PBMC) mounted an enhanced in vitro proliferative response to CPFX and/or NRFX or MXFX in all patients. Patch tests were positive after 24 and 48 h in three out of the six patients. From two patients, CPFX- and MXFX-specific CD4(+)/CD8(+) T cell receptor (TCR) alphabeta(+) TCC were generated to investigate the nature of the drug-T cell interaction as well as the cross-reactivity with other quinolones. The use of eight different quinolones as antigens (Ag) revealed three patterns of cross-reactivity: clones exclusively reacting with the eliciting drug, clones with a limited cross-reactivity and clones showing a broad cross-reactivity. The TCC recognized quinolones directly without need of processing and without covalent association with the major histocompatability complex (MHC)-peptide complex, as glutaraldehyde-fixed Ag-presenting cells (APC) could present the drug and washing quinolone-pulsed APC removed the drug, abrogating the reactivity of quinolone-specific TCC. CONCLUSION: Our data show that T cells are involved in delayed immune reactions to quinolones and that cross-reactivity among the different quinolones is frequent.

New therapies for pneumococcal meningitis

The treatment of pneumococcal meningitis remains a major challenge, as reflected by the continued high morbidity and case fatality of the disease. The worldwide increase of penicillin-resistant pneumococci and more recently cephalosporin- and vancomycin-tolerant pneumococci has jeopardised the efficacy of standard treatments based on extended spectrum cephalosporins alone or in combination with vancomycin. This review provides a summary of newly developed antibiotics tested in the rabbit meningitis model. In particular, newer beta-lactam monotherapies (cefepime, meropenem, ertapenem), recently developed quinolones (garenoxacin, gemifloxacin, gatifloxacin, moxifloxacin) and a lipopeptide antibiotic (daptomycin) are discussed. A special emphasis is placed on the potential role of combination treatments with some of the new compounds, which are of interest based on the background of increasing resistance problems due to their often synergistic activity in the rabbit model of pneumococcal meningitis.

Fluoroquinolones in the Treatment of Meningitis

The continuous increase of resistant pathogens causing meningitis has limited the efficacy of standard therapeutic regimens. Due to their excellent activity in vitro and their good penetration into the cerebrospinal fluid (CSF), fluoroquinolones appear promising for the treatment of meningitis caused by gram-negative microorganisms, ie, Neisseria meningitidis and nosocomial gram-negative bacilli. The newer fluoroquinolones (moxifloxacin, gemifloxacin, gatifloxacin, and garenoxacin) have excellent activity against gram-positive microorganisms. Studies in animal models and limited clinical data indicate that they may play a future role in the treatment of pneumococcal meningitis. Analysis of pharmacodynamic parameters suggests that CSF concentrations that produce a C(peak)/minimal bactericidal concentration (MBC) ratio of at least 5 and concentrations above the MBC during the entire dosing interval are a prerequisite for maximal bactericidal activity in meningitis. Of interest, newer fluoroquinolones act synergistically with vancomycin and beta-lactam antibiotics (ceftriaxone, cefotaxime, meropenem) against penicillin-resistant pneumococci in experimental rabbit meningitis, potentially providing a new therapeutic strategy. Clinical trials are needed to further explore the usefulness of quinolones as single agents or in combination with other drugs in the therapy of pneumococcal meningitis.