Ofloxacin. A reappraisal of its antimicrobial activity, pharmacology and therapeutic use

Exploring the environmental pathways and challenges of fluoroquinolone antibiotics: A state-of-the-art review

Fluoroquinolone (FQ) antibiotics have become a subject of growing concern due to their increasing presence in the environment, particularly in the soil and groundwater. This review provides a comprehensive examination of the attributes, prevalence, ecotoxicity, and remediation approaches associated with FQs in environmental matrices. The paper discusses the physicochemical properties that influence the fate and transport of FQs in soil and groundwater, exploring the factors contributing to their prevalence in these environments. Furthermore, the ecotoxicological implications of FQ contamination in soil and aquatic ecosystems are reviewed, shedding light on the potential risks to environmental and human health. The latter part of the review is dedicated to an extensive analysis of remediation approaches, encompassing both in-situ and ex-situ methods employed to mitigate FQ contamination. The critical evaluation of these remediation strategies provides insights into their efficacy, limitations, and environmental implications. In this investigation, a correlation between FQ antibiotics and climate change is established, underlining its significance in addressing the Sustainable Development Goals (SDGs). The study further identifies and delineates multiple research gaps, proposing them as key areas for future investigational directions. Overall, this review aims to consolidate current knowledge on FQs in soil and groundwater, offering a valuable resource for researchers, policymakers, and practitioners engaged in environmental management and public health.

Abdel Salam R, M. Hadad G, Abdelshakour MA. Ecological spectroscopic methodologies for quantifying co-administered drugs in human plasma by photochemical quantum mechanical simulation

Urinary tract infections (UTIs) constitute the second most prevalent bacterial infections in the elderly demographic. The treatment landscape involves various antibiotics targeting the causative organisms; nevertheless, the emergence of resistance significantly impacts therapeutic effectiveness. Presently, a fixed-dose pharmaceutical combination is advocated to optimize patient outcomes by mitigating the risks of bacterial resistance and associated side effects. Ofloxacin (OFL) and cefpodoxime proxetil (CPD) combinations, co-administered with flavoxate hydrochloride (FLV), have demonstrated efficacy in UTI cases, offering relief from concomitant symptoms. In the pharmaceutical market, fixed-dose combinations have gained prominence, driven by advantages such as enhanced patient medication adherence and compliance. In the realm of analytical chemistry, the integration of green practices in the initial phases of method development is exemplified by the Greenness by Design (GbD) strategy. While univariate spectroscopic methods are conventionally considered suboptimal compared to chemometric techniques for resolving intricate mixtures, GbD approach, when applied to UV spectroscopy, enable univariate methods to attain comparable or superior outcomes. GbD adopts a systematic approach to optimize experimental conditions, minimizing environmental impact and maximizing analytical performance. Critical to GbD applications in UV spectroscopy is solvent selection, influencing spectral resolution and measurement sensitivity. GbD employs a combination of in-vitro and in-silico experiments to evaluate solute-solvent interactions with underlying photochemical quantum phenomena affecting the resulting spectral morphology, identifying an optimal compromise solvent with high resolution and minimal ecological impact. Consequently, it facilitates the efficient resolution of spectral overlapping and determination of complex mixtures in UV spectroscopy using univariate methods. Comparative analysis with chemometric techniques, acknowledged as potent spectral resolving methods, demonstrated that GbD-based univariate methods performed equivalently. The methodology was validated according to ICH recommendations, establishing a linear quantitation range (2-30 μg/mL) and a limit of detection (0.355-0.414 μg/mL) for the three drugs in human plasma. The greenness of the developed methodology was affirmed through the AGREE assessment protocol, confirming its environmentally conscious attributes.

Three developed spectrophotometric methods for determination of a mixture of ofloxacin and ornidazole; application of greenness assessment tools

This work is dedicated to the greenness estimation of three proposed spectrophotometric techniques [e.g., ratio difference (RD), mean centering of ratio spectra (MCR) and continuous wavelet transform of ratio spectra (CWT)] for the determination of a binary combination named Ofloxacin (OFL) and Ornidazole (ORN). Applying the green analytical chemistry methods to assess the proposed methods has widely attained the analytical community care. The greenness assessment was performed via three evaluation approaches; the "Analytical Eco-Scale", the "National Environmental Method Index" (NEMI) and "Green Analytical Procedure Index" (GAPI). Following the examination of the zero spectrum of OFL and ORN, it is observed that OFL and ORN spectra are overlapped, so they can be detected by the methods mentioned previously. The ratio difference method was carried out at wavelengths of 294.6 nm and 265.6 nm for OFL, 292 nm and 315 nm for ORN. The linear range was (2-15 µg/mL) for OFL and (3-30 µg/mL) for ORN. The MCR method based on the use of mean centered ratio spectra in dual steps and calculating the second ratio spectra mean centered values at 294.6 nm for OFL and 315 nm for ORN. The continuous wavelet transformation which carried out using MATLAB at wavelengths of 265 nm for OFL and 306 for ORN. These techniques were intended for the binary mixture analysis in bulk powder and pharmaceutical formulations with high recoveries. The developed methods were validated according to ICH guidelines. All techniques were statistically compared to either an official method for OFL or a reported method for ORN and the results indicate that there were not any significant differences.

A Literature-Based Review and Analysis of the Pharmacodynamics of the Dose Frequency of Topical 0.3% Ciprofloxacin and 0.3% Ofloxacin in the Day-1 Treatment of Bacterial Keratitis

Purpose: To determine the appropriate dose frequency for the second-generation fluoroquinolones (2FQs), ciprofloxacin 0.3% and ofloxacin 0.3%, in the day-1 treatment of bacterial keratitis (BK) based on the corneal concentrations achievable and required Minimum Inhibitory Concentration₉₀ (MIC₉₀) of common BK isolates. Methods: Literature-based ocular MIC₉₀ required to treat bacterial isolates of BK patients were determined for each fluoroquinolone. Published corneal concentrations for each 2FQ, and the drop regimens used to reach these concentrations, were then analyzed to determine the relationship between the corneal 2FQ concentration and the amount of drug applied per hour and the total amount applied. Results: Significant relationships were found to exist for corneal concentrations of both ciprofloxacin and ofloxacin and the amount of drug applied per hour (both P = 0.005), and the total amount of drug applied (P = 0.003 and P = 0.0004, respectively). Derived ciprofloxacin drops/hour corneal concentrations agreed well with both a literature-based regimen and the manufacturers' day-1 drop regimen for various MIC₉₀. Derived ofloxacin drops per hour indicated a higher rate than that suggested by the manufacturer. Conclusions: Both a literature-based and the manufacturers' drop regimens for the day-1 treatment of BK using 0.3% ciprofloxacin have a pharmacodynamic basis, which is related to the required MIC₉₀ of commonly encountered isolates in BK. Dose frequency for 0.3% ofloxacin should be in line with the manufacturers' maximum suggested drop regimen. Commonly suggested drop regimens below these recommendations for either FQ may need to be revised in view of these findings.

Effects of ofloxacin on the structure and function of freshwater microbial communities

Ofloxacin (OFL) is a broad-spectrum fluoroquinolone antibiotic frequently used in clinic for treating bacterial infections. The discharged OFL would inevitably enter into aquatic ecosystems, affecting the growth of non-target microorganisms, which may result in micro-ecosystem imbalance. To the best of our knowledge, researches in this area are rather sparse. The present study evaluated the response of photosynthetic microorganisms (cyanobacteria, eukaryotic algae) and aquatic microbial community to OFL in a microcosm. Results showed that ofloxacin presented an inhibitory effect on the growth Microcystis aeruginosa. Although 0.1 mg/L OFL has no significant impact on alpha diversity of the microbial communities, it obviously altered the structure and decreased the species interaction of prokaryotic community by reducing the capacities of nitrogen fixation, photosynthetic and metabolic capacity of the microbial community. This study pointed out that the residual OFL in water would disturb the balance of the aquatic micro-ecology, suggesting that more attentions should be given to the negative effects of antibiotics and other bioactive pollutants on aquatic environments.

Piperazine based antimicrobial polymers: a review

Microbial infections are a life threatening concern in several areas, which include the biomedical sector, healthcare products, water purification systems, and food packaging. Polymers with low molecular weight bioactive agents or disinfectants help the scientific community to reduce the lethality rate caused by pathogenic microbes. Antimicrobial polymeric approach is one of the advanced approaches made by researchers in concern with the problems associated with small molecules that restrict their applications in broad spectrum. History reveals the synthesis of numerous antimicrobial polymers using various antimicrobial agents but lacks the use of piperazine molecule, which is of pharmaceutical importance. This review gives an insight into the current and future perspective for the development of piperazine-based antimicrobial polymers.

Electrocatalytic removal of fluroquinolones from simulated pharmaceutical effluent: Chemometric analysis, chemical blueprint of electrodes and generated sludge

Electrocatalytic removal of fluroquinolones from simulated pharmaceutical effluent is studied in this work. The effects of parameters like NaCl concentration, pH and initial concentration of Ofloxacin were studied. The synergistic effect of H₂O₂ on the degradation of Ofloxacin paves the way to move towards radical based chemistry. The process was modelled and statistically evaluated through Central Composite Design approach towards the maximum concentration of Ofloxacin degraded (for 0.8 mM) as 0.46 mM at pH-3.0 and the concentration of H₂O₂ at 0.2 mM. The model was analyzed mathematically and observed as saddle response based on canonical and ridge analysis. The process follows pseudo first order kinetics with k = 0.047 min^-1 and reaction rate of 13.6 mg.L^-1.min^-1. The mineralization efficiency of the process was studied using Total Organic Carbon analysis and 76.5% removal efficiency was obtained on the simulated pharmaceutical effluent containing Ofloxacin, Ciprofloxacin and Norfloxacin. The crystal structure of the green and red colour sludge was determined by XRD to be lepidocrocite (a = 3.87 Å, b = 12.4 Å, c = 3.06 Å) and gupeiite (a = 5.6620 Å), respectively. The elemental composition of sludge and electrodes were found using SEM-EDX. Morphological change in electrode surface was determined using roughness plot.

Anti-inflammatory, pro-proliferative and antimicrobial potential of the compounds isolated from Daemonorops draco (Willd.) Blume

ETHNO-PHARMACOLOGICAL RELEVANCE

Daemonorops draco (D. draco) commonly known as "Dragon's blood" is one of the most used plants by Momok, Anak Dalam and Talang Mamak tribes from Indonesia as a remedy for wound healing.

AIM OF THE STUDY

This study aimed to identify the extract, fractions and compounds responsible for the anti-inflammatory and pro-proliferative activities of the D. draco resin. Additionally, the antimicrobial activity against two bacteria and one yeast species was analysed.

MATERIALS AND METHODS

Bio-guided isolation of compounds with anti-inflammatory, pro-proliferative and antimicrobial activities from the D. draco resin was carried out by measuring: the inhibition of NF-κB and activation of Nrf2 in THP-1, HaCaT, NIH-3T3 cells; cell proliferation in NIH-3T3 and HaCaT cells; and the antimicrobial effect on E. coli, S. aureus and C. albicans.

RESULTS

Guided isolation by bioassay gave rise to the isolation and characterisation by nuclear magnetic resonance and mass spectrometry of three compounds: 1 (Bexarotene), 2 (Taspine) and 3 (2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone). All compounds showed NF-κB inhibitory activity with IC₅₀ values of 0.10-0.13, 0.22-0.24 and 3.75-4.78 μM, respectively, while the positive control, Celastrol, had an IC₅₀ of 7.96 μM. Likewise, all compounds showed an activating effect of Nrf2 with EC₅₀ values of 5.34-5.43, 163.20-169.20 and 300.82-315.56 nM, respectively, while the positive control, CDDO-Me, had an EC₅₀ of 0.11 nM. In addition, concerning the pro-proliferative activity, compound 1 (IC₅₀ = 8.62-8.71 nM) showed a capacity of 100%, compound 2 (IC₅₀ = 166-171 nM) showed a capacity of 75%, and compound 3 (IC₅₀ = 469-486 nM) showed a capacity of 65%, while FSB 10% (positive control) had a pro-proliferative activity of 100% in the NIH3T3 cell lines (fibroblasts) and HaCaT (keratinocytes). Finally, all the compounds showed antimicrobial activity with MIC values of 0.12-0.16, 0.31-0.39 and 3.96-3.99 μM, respectively, in S. aureus, E. coli and C. albicans strains, while the positive control, Ofloxacin, had a MIC of 27.65 μM.

CONCLUSION

This study managed to isolate, for the first time, three compounds (Bexarotene, Taspine and 2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone) from the resin of D. draco, with anti-inflammatory, and pro-proliferative as well as antimicrobial activities.

Size-Dependent Inhibitory Effects of Antibiotic Nanocarriers on Filamentation of E. coli

Multidrug membrane transporters exist in both prokaryotic and eukaryotic cells, which causes multidrug resistance (MDR) and urgent need of new and more effective therapeutic agencies. In this study, we used three different sized antibiotic nanocarriers to study their mode of actions and their size-dependent inhibitory effects against Escherichia coli (E. coli). The antibiotic nanocarriers (AgMUNH-Oflx NPs) with 8.6×10², 9.4×10³ and 6.5×10⁵ Oflx molecules per nanoparticle (NP) were prepared by functionalizing the Ag NPs (2.4 ± 0.7, 13.0 ± 3.1 and 92.6 ± 4.4 nm) with a monolayer of 11-amino-1-undecanethiol (MUNH₂) and covalently linking ofloxacin (Oflx) with the amine group of AgMUNH₂ NPs, respectively. We designed a modified cell culture medium for nanocarriers to be stable (non-aggregated) over 18 h of cell culture, which enables us to quantitatively study their size and dose dependent inhibitory effects against E. coli. We found that inhibitory effects of Oflx against E. coli highly depend upon dose of Oflx and size of nanocarriers, showing that the equal amount of Oflx delivered by the largest nanocarriers (92.6 ± 4.4 nm) were the most potent with the lowest minimum inhibitory concentration (MIC₅₀) and created the longest and highest percentage of filamentous cells, while the smallest nanocarriers (2.4 ± 0.7) were the least potent with the highest MIC₅₀ and produced the shortest and lowest percentage of filamentous cells. Interestingly, the same amount of Oflx on 2.4 ± 0.7 nm nanocarriers showed the 2x higher MIC and created the 2x shorter filamentous cells than free Oflx, while the Oflx on 13.0 ± 3.1 and 92.6 ± 4.4 nm nanocarriers exhibited 2x and 6x lower MICs, and produced 2x and 3x longer filamentous cell than free Oflx, respectively. Notably, three sized AgMUNH₂ NPs (absence of Oflx) showed negligible inhibitory effects and did not create filamentous cells. The results show that the filamentation of E. coli highly depends upon the sizes of nanocarriers, which leads to the size-dependent inhibitory effects of nanocarriers against E. coli.

Co-Amorphous Formation of High-Dose Zwitterionic Compounds with Amino Acids To Improve Solubility and Enable Parenteral Delivery

Solubilization of parenteral drugs is a high unmet need in both preclinical and clinical drug development. Recently, co-amorphous drug formulation has emerged as a new strategy to solubilize orally dosed drugs. The aim of the present study is to explore the feasibility of using the co-amorphous strategy to enable the dosing of parenteral zwitterionic drugs at a high concentration. A new screening procedure was established with solubility as the indicator for co-amorphous co-former selection, and lyophilization was established as the method for co-amorphous formulation preparation. Various amino acids were screened, and tryptophan was found to be the most powerful in improving the solubility of ofloxacin when lyophilized with ofloxacin at a 1:1 weight ratio, with more than 10 times solubility increase. X-ray powder diffraction showed complete amorphization of both components, and an elevated T_g compared with the theoretical value was observed in differential scanning calorimetry. Fourier transform infrared spectroscopy revealed that hydrogen bonding and π-π stacking were possibly involved in the formation of a co-amorphous system in the solid state. Further solution-state characterization revealed the involvement of ionic interactions and π-π stacking in maintaining a high concentration of ofloxacin in solution. Furthermore, co-amorphous ofloxacin/tryptophan at 1:1 weight ratio was both physically and chemically stable for at least 2 months at 40 °C/75% RH. Lastly, the same screening procedure was validated with two more zwitterionic compounds, showing its promise as a routine screening methodology to solubilize and enable the parenteral delivery of zwitterionic compounds.

High Dose Ofloxacin-induced Bimodal Hallucinations in a 4 Years Old Child

Ofloxacin is a commonly used quinolone antibiotic both in adults as well as children. It is generally safe and well tolerated. Rarely, neurological and psychiatric adverse reactions are reported to occur with ofloxacin. We report a case of a child who developed delirium after ofloxacin treatment, that resolved after medication discontinuation and treatment with low dose olanzapine.

Design, characterization, and aerosolization of organic solution advanced spray-dried moxifloxacin and ofloxacin dipalmitoylphosphatidylcholine (DPPC) microparticulate/nanoparticulate powders for pulmonary inhalation aerosol delivery

The aim of this study was to design and develop respirable antibiotics moxifloxacin (MOXI) hydrochloride and ofloxacin (OFLX) microparticles and nanoparticles, and multifunctional antibiotics particles with or without lung surfactant 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) for targeted dry powder inhalation delivery as a pulmonary nanomedicine. Particles were rationally designed and produced by advanced spray-drying particle engineering from an organic solution in closed mode (no water) from dilute solution. Scanning electron microscopy indicated that these particles had both optimal particle morphology and surface morphology, and the particle size distributions were suitable for pulmonary delivery. Comprehensive and systematic physicochemical characterization and in vitro aerosol dispersion performance revealed significant differences between these two fluoroquinolone antibiotics following spray drying as drug aerosols and as cospray-dried antibiotic drug: DPPC aerosols. Fourier transform infrared spectroscopy and confocal Raman microspectroscopy were employed to probe composition and interactions in the solid state. Spray-dried MOXI was rendered noncrystalline (amorphous) following organic solution advanced spray drying. This was in contrast to spray-dried OFLX, which retained partial crystallinity, as did OFLX:DPPC powders at certain compositions. Aerosol dispersion performance was conducted using inertial impaction with a dry powder inhaler device approved for human use. The present study demonstrates that the use of DPPC offers improved aerosol delivery of MOXI as cospray-dried microparticulate/nanoparticulate powders, whereas residual partial crystallinity influenced aerosol dispersion of OFLX and most of the compositions of OFLX:DPPC inhalation powders.

Preparation and evaluation of ofloxacin-loaded palmitic acid solid lipid nanoparticles

The purpose of this study was to use solid lipid nanoparticles (SLN) to improve the pharmacological activity of ofloxacin. Ofloxacin-loaded SLN were prepared using palmitic acid as lipid matrix and poly vinyl alcohol (PVA) as emulsifier by a hot homogenization and ultrasonication method. The physicochemical characteristics of SLN were investigated by optical microscope, scanning electron microscopy, and photon correlation spectroscopy. Pharmacokinetics was studied after oral administration in mice. In vitro antibacterial activity and in vivo antibacterial efficacy of the SLN were investigated using minimal inhibitory concentrations (MIC) and a mouse protection model. The results demonstrated that the encapsulation efficiency, loading capacity, diameter, polydispersivity index, and zeta potential of the nanoparticles were 41.36% ± 1.50%, 4.40% ± 0.16%, 156.33 ± 7.51 nm, 0.26 ± 0.04, and −22.70 ± 1.40 mv, respectively. The SLN showed sustained release and enhanced antibacterial activity in vitro. Pharmacokinetic results demonstrated that SLN increased the bioavailability of ofloxacin by 2.27-fold, and extended the mean residence time of the drug from 10.50 to 43.44 hours. Single oral administrations of ofloxacin-loaded nanoparticles at 3 drug doses, 5 mg/kg, 10 mg/kg, and 20 mg/kg, all produced higher survival rates of lethal infected mice compared with native ofloxacin. These results indicate that SLN might be a promising delivery system to enhance the pharmacological activity of ofloxacin.

Therapeutic drug monitoring in antituberculosis chemotherapy: clinical perspectives

BACKGROUND

Therapeutic drug monitoring (TDM) represents an area where multidisciplinary service is rendered for optimization of clinical care, through enabling maximum drug therapeutic efficacy and minimum drug toxicity. This is a recently developed field for antituberculosis chemotherapy. The other goals of TDM principally include study and management of pharmacokinetic drug-drug and drug-disease interactions as well as the evaluation of new fixed-dose combinations (FDC) developed for treatment of tuberculosis.

CONCLUSION

In the years to come, with the advancement in knowledge, technology and expertise, it is hoped that TDM, as a novel paradigm of care in tuberculosis, may gain expanding indications and reach a new horizon.

Ofloxacin/beta-cyclodextrin complexation

Ofloxacin (OFX) is a fluorquinolone characterized by photochemical instability. With the goal to improve its photostability in aqueous solutions, the complexation of ofloxacin with beta-cyclodextrin was investigated. The complexes showed a water solubility enhancement of approximately 2.6 times; nevertheless, the photodegradation of ofloxacin was not reduced. The complexes obtained were characterized by thermal and 1H nuclear magnetic resonance (NMR) analysis, which revealed an interaction between ofloxacin and beta-cyclodextrin. The last analysis indicated that only partial inclusion of the N-methylpiperazinyl moiety occurred, which can explain the fact that photostabilization was not improved. This partial inclusion phenomenon could be explained also by computer-aided molecular modeling.

Influence of dose on the distribution kinetics of ciprofloxacin and ofloxacin in the isolated hindlimb of the rat

The aim of this study was to determine whether the dose influences the distribution kinetics of ciprofloxacin and ofloxacin in muscle- bone- and skin-tissues included in the isolated hindlimb of the rat. Experiments were carried out in the isolated perfused hindlimb of the rat, administering a single dose of 45, 450 or 900 microg of each quinolone as a bolus injection. Outflow perfusate samples were collected for 20 min and drug levels were determined by an HPLC technique. The mean transit time (MTT) and the distribution volume of ciprofloxacin significantly increased with the dose injected (MTT=1.47+/-0.69, 8.74+/-0.27 and 9.52+/-2.95 min for 45, 450 and 900 microg, respectively). A similar situation was observed with ofloxacin, although the increase in these parameters was less pronounced (MTT=3.65+/-0.86, 7.92+/-2.03 and 8.32+/-1.70 min for 45, 450 and 900 microg, respectively). The distribution of ciprofloxacin and ofloxacin in the rat hindlimb appears to be a dose-dependent process, at least for the dose range considered in this study. This might explain the high variability in the distribution coefficients reported for these drugs in literature.

Penetration of topical and oral ofloxacin into the aqueous and vitreous humor of inflamed rabbit eyes

PURPOSE

This study aimed to investigate the penetration of topical and oral ofloxacin into aqueous humor and vitreous humor in post-traumatic endophthalmitis model in rabbits.

METHODS

A standardized intraocular infection after penetrating injury was made in the right eyes of 16 rabbits. Intraocular infection was induced by intravitreal injection of a suspension of Staphylococcus aureus. The intact left eyes were maintained as controls. The animals were divided randomly into two groups. (1) In the topical group, two drops of ofloxacin 0.3% eyedrops were instilled to both eyes every 30 min for 4 h. (2) In the topical-oral group, two doses of 25 mg/kg of ofloxacin at 12-h intervals were given orally, then the protocol of the first group was applied. Aqueous and vitreous humor samples were taken 30 min after the last drop. Ofloxacin concentrations were measured by using HPLC.

RESULTS

Mean aqueous levels of ofloxacin in control eyes were: 3.25 +/- 2.55 microg/ml in topical group. 4.58 +/- 5.39 microg/ml in topical-oral group. Mean aqueous levels in inflamed eyes were: 5.21 +/- 4.55 microg/ml in topical group, 10.34 +/- 8.88 microg/ml in topical-oral group. Mean vitreous levels of ofloxacin in control eyes were: 0.17 +/- 0.07 microg/ml in topical group, 1.30 +/- 1.23 microg/ml in topical-oral group. Mean vitreous levels in inflamed eyes were: 0.35 +/- 0.22 microg/ml in topical group, 3.48 +/- 2.69 microg/ml in topical-oral group. There was no significant difference among the groups (P > 0.05), however.

CONCLUSIONS

The result of this study suggests that oral supplementation of ofloxacin to topical instillation increased the ocular levels of ofloxacin in the post-traumatic endophthalmitis model. Mean drug concentrations in aqueous and vitreous humors were above the 90% minimum inhibitory concentrations (MIC90) for most of the common microorganisms causing endophthalmitis in all eyes, except in the vitreous humors of the intact eyes instilled topically.

Outcomes of patients with multidrug-resistant pulmonary tuberculosis treated with ofloxacin/levofloxacin-containing regimens

OBJECTIVE

To analyze outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) treated with ofloxacin/levofloxacin-containing regimens.

MATERIALS AND METHODS

From February 1990 through June 1997, 63 MDR-TB patients (with bacillary resistance to at least isoniazid and rifampin in vitro) were analyzed retrospectively. Twenty-two patients (34.9%) had had no previous antituberculosis chemotherapy. Each patient received either ofloxacin (53) or levofloxacin (10) even though 13 patients had bacilli resistant to ofloxacin in vitro. The other accompanying drugs mainly included aminoglycosides, cycloserine, ethionamide/prothionamide, and pyrazinamide. Sputum smear and culture examinations for acid-fast bacilli (AFB) were performed monthly for the initial 6 months and then at 2- to 3-month intervals until the end of treatment. Comparison was made between clinical successes and failures using univariate and multiple logistic regression analyses for the following variables: age, sex, presence of cavitation, extent of disease, sputum smear positivity, in vitro resistance to ofloxacin, in vitro resistance to streptomycin and/or ethambutol, treatment adherence, and the number of drugs per regimen.

RESULTS

Fifty-one patients (81.0%) were cured, nine patients (14.3%) failed, and three patients (4.7%) died. For the entire group, the mean duration of treatment was 14.0 months, and the mean number of drugs was 4.7. Mean durations of chemotherapy in successful and failed patients were 14.5 and 14.2 months, respectively. Mean time for sputum smear and culture conversions were 1.7 and 2.1 months, respectively. Only cavitation, resistance to ofloxacin, and poor adherence were found to be variables independently associated with adverse outcomes (p < 0.05; odds ratios = 15.9, 13.5, 12.8, respectively). Negative sputum cultures after 2 and 3 months of therapy were 100% predictive of cure. Positive sputum cultures after 2 and 3 months were 52.3% and 84.6% predictive of failure, respectively. One patient (2.1%) relapsed after apparent cure. Twenty-five patients experienced adverse drug reactions, but only 12 of them needed drug modifications.

CONCLUSION

Most MDR-TB patients can be treated effectively with ofloxacin/levofloxacin-containing regimens. Presence of cavitation, resistance to ofloxacin in vitro, and poor adherence to therapy portend treatment failure. Monitoring monthly sputum culture for AFB in the initial months of chemotherapy helps predict clinical outcomes.

Penetration of topical, oral, and combined administered ofloxacin into the subretinal fluid

AIMS

To assess the subretinal fluid (SRF) levels of ofloxacin following topical, oral or combined administration.

METHODS

31 patients undergoing conventional retinal reattachment surgery were randomly assigned to three groups. Nine patients received topical ofloxacin, 11 patients received oral ofloxacin, and the other 11 patients received combined administration. Collected SRF samples were analysed for drug level by using high performance liquid chromatography.

RESULTS

SRF drug levels after oral and combined administration were significantly higher than that after topical administration (p=0.0002 and p=0.0002, respectively) while there was no significant difference between oral and combined administration (p=0.0844).

CONCLUSIONS

Ocular bioavailability of ofloxacin in SRF after oral and combined administration is equivalent. The addition of oral ofloxacin to topical therapy increased drug SRF penetration sixfold.

Therapeutic drug monitoring in antituberculosis chemotherapy

Therapeutic drug monitoring in antituberculosis chemotherapy may play a strategic role in improving outcomes in selected patients. The most important use is in assisting clinicians to optimize therapy to achieve success and minimize toxicity. The other principal indication lies in the management of interaction of antituberculosis drugs with other drugs.

Increasing ciprofloxacin resistance among prevalent urinary tract bacterial isolates in Bangladesh

Ciprofloxacin was evaluated along with other commonly used antibiotics against a total of 425 clinical isolates obtained from urine samples. Samples were collected from outdoor patients from different parts of Dhaka city. Susceptibility tests were done by the standardized disk diffusion method. Among the tested drugs, the percent susceptible rates observed were: ciprofloxacin (74%), ampicillin (29%), cephalexin (54%) and trimethoprim-sulfamethoxazole (43%) tested against all organisms; gentamicin (73%) tested against gram-negative organisms and erythromycin (72%) tested against gram-positive organisms. Ciprofloxacin showed better activity against gram-negative isolates (80%) compared to the other antibiotics. However, strains highly resistant to ciprofloxacin were detected among commonly isolated gram-negative urinary pathogens: Escherichia coli (18%), Klebsiella species (19%) and Pseudomonas species (30%). Overall susceptibility rate for gram-positive cocci was significantly low for all the antibiotics tested including ciprofloxacin (62%). Minimal inhibitory concentration (MIC) of ciprofloxacin was measured for all resistant and susceptible urinary tract infection (UTI) isolates. This study indicates emerging ciprofloxacin resistance among most UTI bacterial pathogens. Increasing resistance against ciprofloxacin demands coordinated monitoring of its activity, and rationale use of the antibiotic in UTI.

Antimicrobial interactions (synergy) of teicoplanin with two broad-spectrum drugs (cefotaxime, ofloxacin) tested against gram-positive isolates from Germany and the United States

Teicoplanin, a glycopeptide, has been widely used in some nations alone and in empiric therapy combinations to address infections caused by Gram-positive cocci. However, glycopeptide resistance and the increasing incidence of oxacillin-resistant staphylococci have compromised contemporary chemotherapy. In this study, teicoplanin was tested in combinations with ampicillin, cefotaxime with and without desacetylcefotaxime, and ofloxacin against 151 Gram-positive cocci to assess the potential for enhanced action. The strains included recent isolates from the United States and Germany having well-characterized resistance mechanisms (oxacillin-resistant staphylococci, vancomycin-resistant enterococci), each tested by NCCLS methods, checkerboard synergy tests, and kill-curves. Teicoplanin alone was active (MIC90s, 0.25-2 micrograms/mL) against all species except vanA enterococci. Drug interactions of teicoplanin with beta-lactams revealed synergy and partial synergy versus oxacillin-resistant Staphylococcus spp. (67-100%) and vancomycin-resistant enterococci (70-100%), many at clinically achievable drug concentrations. However, confirming kill-curve experiments showed static action and no significant bactericidal effect. Combinations of ofloxacin with teicoplanin or cefotaxime plus desacetylcefotaxime showed a dominant additive and indifferent interaction. Teicoplanin continues to be a viable alternative to vancomycin, especially in combination therapy with selected broad-spectrum cephalosporins or fluoroquinolones. Many emerging pathogens that test resistant to individual drugs appear to be inhibited by tested combinations, extending their potential clinical utility.

Corneal tissue levels of topically applied ofloxacin

PURPOSE

To evaluate the levels of ofloxacin (Ocuflox) in human corneal tissue in patients exposed to various dosing regimens and application methods.

SETTING

Corneal Consultants of Indiana, Indianapolis, Indiana, USA.

METHODS

Forty patients meeting inclusion criteria were recruited from persons scheduled to have penetrating keratoplasty (PKP). Patients were placed into one of two study groups of 20 each based on dosing regimen and application method. The SAS GLM (General Linear Models) procedure was used to test for differences in mean Ocuflox tissue concentration among study groups and for interaction effects of preoperative diagnosis, trephine size, dosing regimen, and corneal integrity.

RESULTS

Corneal tissue concentrations of Ocuflox were elevated significantly by varying drug application methods and dosing schedules before PKP. Eyes receiving medication every 15 minutes for 4 hours had significantly higher levels of Ocuflox than those receiving the drug in six doses over 24 hours before surgery. Ocuflox concentrations exceeded the MIC90 (minimum inhibitory concentration) for key ocular pathogens in essentially all cornea specimens studied.

CONCLUSION

Ocuflox penetration was improved by administering it in a controlled setting at 15 minute intervals over 4 hours. The drug provided high tissue levels in both the cornea and aqueous humor, which together with its broad range of antibacterial coverage, should make it a good choice for prophylactic treatment.

Suspected Ofloxacin-Induced Seizures in an Elderly Patient

Objective:

To report a case of probable ofloxacin-induced seizures.

Case Summary:

A 74-year-old white man received a single intravenous dose of ofloxacin administered over a 60-minute period. Approximately 4 hours later, he developed seizure-like tremors in all extremities, fecal incontinence, and shortness of breath with harsh, labored breathing. Ofloxacin was discontinued, and the seizure-like tremors subsided within 4 hours of onset.

Discussion:

The time course of events suggested that ofloxacin was the cause of a suspected seizure in this patient. Other causes of seizure were ruled out. Seizures have been reported in less than 1% of patients receiving ofloxacin.

Conclusions:

Ofloxacin can cause seizures, and healthcare providers should be aware of the potential for this adverse effect.

Antimicrobial activity of human pancreatic juice and its interaction with antibiotics

Pancreatic juice (PJ) should be a factor of variability in the antimicrobial activity of antibiotics eliminated by the pancreas during pancreatic infections. We studied its effects on the activity of antimicrobial drugs with different mechanisms of action. Samples of pure PJ were collected from 16 patients with stabilized external pancreatic fistulas. The antimicrobial activity of the juice at different concentrations (from 1.25 to 100%) alone and in combination with mezlocillin, imipenem, ceftriaxone, gentamicin, ofloxacin, and ciprofloxacin was studied by a microbiological method (continuous turbidimetric recording of bacterial growth). The human PJ showed dose-dependent antimicrobial activity that increased directly with the concentration. The activity of the antibiotics at bactericidal concentrations were not modified by the PJ, while the combination with subinhibitory concentrations produced the following variable and different effects: (i) additivity with mezlocillin, ceftriaxone, gentamicin, and ciprofloxacin and autonomy (no interaction) with imipenem and ofloxacin against Providencia rettgeri and (ii) additivity with ceftriaxone, ofloxacin, gentamicin, imipenem, and mezlocillin and autonomy with ciprofloxacin against Escherichia coli. In the presence of PJ, fluoroquinolones showed constant positive effects, while beta-lactams showed more variable antimicrobial activity. Antibiotic concentrations and PJ pharmacodynamics are the main factors determining the final effect of the interaction in vitro. These results may be useful in choosing antibiotics for the treatment of pancreatic infections when they are supplemented with the pharmacokinetic data for each drug.

Penetration of gentamicin and ofloxacin in human vitreous after systemic administration

BACKGROUND

Data on the penetration of antibiotics into the aqueous humor in man and animals, as well as on the intravitreal penetration in animals, are numerous. Data on their intravitreal penetration in humans, however, are sparce. The intravitreal penetration of gentamicin was studied in different ocular pathologies to see whether these alter the vitreal pharmacodynamics. The intravitreal penetration of ofloxacin, a fluoroquinolone, was determined to see whether levels sufficient to treat infectious endophthalmitis could be reached.

METHODS

The intravitreal penetration of gentamicin and ofloxacin was studied in patients undergoing pars plana vitrectomy for various ocular pathologies. Those with recent hemorrhages and those already receiving general antibiotic treatment were excluded.

RESULTS

Gentamicin was found to penetrate the vitreous very poorly. No difference could be found between the various pathologies: trauma, diabetes, proliferative vitreoretinopathy, longstanding vitreous hemorrhage and macular pucker gave the same poor penetration. The ofloxacin levels were higher but did not reach the MIC90 levels of most organisms involved in bacterial endophthalmitis.

CONCLUSION

The hemato-ocular barrier is more difficult to cross than originally thought. Different ocular pathologies do not alter the ocular barrier substantially. Ofloxacin alone does not seem to be sufficient for the treatment of established bacterial endophthalmitis.

Ofloxacin versus trimethoprim-sulfamethoxazole in the treatment of patients with acute exacerbation of chronic bronchitis. Study of Ofloxacin in Lower Respiratory Tract Infections Research Group

An open-label, randomized, comparative, parallel-group study of ofloxacin and trimethoprim-sulfamethoxazole was performed in 162 outpatients diagnosed with acute exacerbation of chronic bronchitis. Ofloxacin 400 mg once daily was administered orally; the dose could be increased to 400 mg twice daily if patients had not improved after 72 hours of treatment. The other treatment group received trimethoprim-sulfamethoxazole 960 mg twice daily orally. The duration of treatment was 10 to 14 days for both treatment groups. Successful clinical response (defined as cure or major improvement in symptoms) was achieved in 65 (80.2%) patients in the ofloxacin group and in 42 (51.9%) patients in the trimethoprim-sulfamethoxazole group; the differences between groups were statistically significant. Bacteriologic success (classified as eradication or presumptive eradication of the causative pathogen) was achieved in 27 (50.0%) patients in the ofloxacin group and in 16 (29.1%) patients in the trimethoprim-sulfamethoxazole group; these differences between groups were also statistically significant. Reinfection occurred in 18 (33.3%) and 4 (7.3%) patients treated with ofloxacin and trimethoprim-sulfamethoxazole, respectively. No serious adverse events were reported.

Ofloxacin: Why the Increased Popularity?

Objective:

To provide a rationale for the increasing use of ofloxacin as a substitute for ciprofloxacin, and to review the appropriate use of these agents.

Data Source:

A MEDLINE search was conducted to identify relevant literature. References in those articles were reviewed for additional published information.

Study Selection:

Published review articles and clinical trials on ofloxacin were reviewed, with particular emphasis on pharmacoeconomics, pharmacodynamics, and studies evaluating the safety and efficacy of ofloxacin.

Data Synthesis:

Ofloxacin is a broad-spectrum antimicrobial agent that has in vitro activity similar to that of ciprofloxacin. Ciprofloxacin exhibits lower minimum inhibitory concentrations for Pseudomonas aeruginosa, and ofloxacin is more active against Chlamydia trachomatis and gram-positive aerobic organisms. Both agents have limited anaerobic activity. Unlike ciprofloxacin, ofloxacin is 100% bioavailable, exhibits a greater area under the concentration curve, contributing to its bactericidal activity, and is eliminated primarily by the kidney. Both ciprofloxacin and ofloxacin have long half-lives, allowing twice-daily dosing. However, because a decrease in renal function often accompanies increasing age, ofloxacin can be administered once daily in the elderly. Both agents have a large volume of distribution and exhibit excellent tissue and cell penetration. Several clinical studies have demonstrated ofloxacin's effectiveness in treating a variety of systemic infections caused by susceptible organisms, including P. aeruginosa. Adverse effects are infrequent with both fluoroquinolones, and if they occur such effects are usually gastrointestinal in nature. Ofloxacin has a much lower incidence of drug interactions, in particular with theophylline and caffeine. Ofloxacin is less expensive than ciprofloxacin.

Conclusions:

Overall, the activity of ofloxacin is similar to that of ciprofloxacin and the two agents are therapeutically equivalent. The data presented warrant routine therapeutic substitution of ofloxacin for ciprofloxacin. Ciprofloxacin should be reserved for instances in which specific prescribing criteria are met.

A double-blind comparative study of ofloxacin otic drops versus neomycin-polymyxin B-hydrocortisone otic drops in the medical treatment of chronic suppurative otitis media

Active chronic suppurative otitis media poses a management problem when patients are being considered for surgical treatment. Topical antibiotics have demonstrated varying degrees of success in the management of discharging ears. The introduction of quinolones has revived interest in these topical agents. This double-blind study compares two antibiotics, namely ofloxacin and neomycin-polymyxin B, with similar in vitro sensitivities to Gram positive and Gram negative organisms. Fifty-two patients were selected randomly and the results show that ofloxacin eardrops have marginal benefits in symptomatic improvement (89 per cent versus 79 per cent, p = 0.27) and bacterial eradication (81 per cent versus 75 per cent, p = 0.81) in active chronic suppurative otitis media. Significantly fewer patients (seven per cent versus 29 per cent, p = 0.04) in the ofloxacin group had active disease at the end of the two-week treatment. We recommend the use of ofloxacin eardrops in managing active chronic suppurative otitis media since it has high clinical efficacy, contains no steroid component and has no demonstrated risk of ototoxicity.

Prevalence of important pathogens and antimicrobial activity of parenteral drugs at numerous medical centers in the United States, I. Study on the threat of emerging resistances: real or perceived? Fluoroquinolone Resistance Surveillance Group

Forty-three medical centers participated in a national (United States) surveillance study of parenteral antimicrobial agents as empiric therapy of pathogens isolated from blood, skin wounds, respiratory tract, and urine (> 8500 strains, 200 per laboratory). All laboratories tested each organism by the same reagent disks and/or Etest (AB Biodisk, Solna, Sweden) strips. Quality control results validated all laboratories for analyses. The most common isolates were Escherichia coli (1648), Staphylococcus aureus (1408), Pseudomonas aeruginosa (1003), Klebsiella species (792), and the enterococci (684). Among the tested drugs the percent susceptible rates observed were ofloxacin (83.4%), ciprofloxacin (82.0%), and cefuroxime (62.9%) tested against all organisms; cefazolin (54.7%) and ceftazidime (76.7%) tested against all nonfastidious aerobes; gentamicin (91.2%), imipenem (95.3%), ticarcillin-clavulanate (78.2%), and ceftriaxone (66.2%) tested against Gram-negative organisms only; and vancomycin (97.9%) and erythromycin (49.2%) tested against Gram-positive aerobes. Several drug-resistant species appear to be emerging or increasing in the United States: (a) vancomycin-resistant enterococci (7.9%, mostly Enterococcus faecium); (b) oxacillin-resistant S. aureus (21.0%); (c) third-generation cephalosporin-resistant Enterobacteriaceae, including E. coli and Klebsiella species with extended-spectrum beta-lactamases (approximately 1.3%-8.6%); (d) penicillin-resistant Streptococcus pneumoniae (17.8%); and (e) ciprofloxacin-resistant P. aeruginosa (14.9%). Fluoroquinolone resistance among the enteric bacilli was confirmed in 60 of 66 referred strains (0.8% of total strains), and cross-resistance was high among ciprofloxacin, ofloxacin, lomefloxacin, fleroxacin, and norfloxacin (98.3%-100%). Seventeen strains of fluoroquinolone-resistant enteric bacilli (0.2% of total) also harbored an ESBL and resistance to aminoglycosides. Clonal spread within medical centers was observed with the ESBL-producing Klebsiella pneumoniae. This national clinical isolate data base continues to demonstrate broad fluoroquinolone efficacy (ofloxacin > ciprofloxacin) against hospital-based pathogens and many strains of emerging resistant bacteria. Continued US surveillance studies are urged to monitor emerging antimicrobial resistance and to guide interventions to minimize its occurrence.

Levofloxacin. A review of its antibacterial activity, pharmacokinetics and therapeutic efficacy

Levofloxacin, an oral fluoroquinolone antibacterial agent, is the optical S-(-) isomer of ofloxacin. In vitro it is generally twice as potent as ofloxacin. Levofloxacin is active against most aerobic Gram-positive and Gram-negative organisms and demonstrates moderate activity against anaerobes. Drug penetration into body tissues and fluids is rapid and widespread after oral administration. In clinical trials conducted in Japan, oral levofloxacin has demonstrated antibacterial efficacy against a variety of infections, including upper and lower respiratory tract, genitourinary, obstetric, gynaecological and skin and soft tissues. In comparative trials with ofloxacin, levofloxacin, at half the daily dosage of ofloxacin, showed equivalent efficacy and a reduced incidence of adverse effects in the treatment of lower respiratory tract and complicated urinary tract infections. Levofloxacin has a tolerability profile similar to that of other oral fluoroquinolones, with gastrointestinal and central nervous system effects reported most commonly. Theophylline dosage adjustment does not appear to be necessary in patients receiving concomitant levofloxacin. Coadministration with antacids or with other drugs containing divalent or trivalent cations reduces levofloxacin absorption. Thus, levofloxacin has potential as a broad spectrum antibacterial drug in the treatment of a variety of infections. However, clinical trials recruiting non-Japanese patients are in progress and these results will form a basis on which future recommendations for the broader use of levofloxacin can be made.

North American (United States and Canada) comparative susceptibility of two fluoroquinolones: ofloxacin and ciprofloxacin. A 53-medical-center sample of spectra of activity. North American Ofloxacin Study Group

Ofloxacin, a newer broad-spectrum fluoroquinolone, was evaluated against > 12,000 clinical isolates in a multicenter surveillance trial in the United States and Canada using the standardized disk diffusion method. A total of 53 geographically diverse clinical microbiology laboratories contributed zone diameter results for ofloxacin, ciprofloxacin, and norfloxacin for urinary tract infection (UTI) isolates; and ofloxacin and ciprofloxacin for respiratory tract infection (RTI) isolates, skin and soft tissue infection (SSTI) isolates, and genital tract pathogen isolates. In both the USA and Canada, ofloxacin was shown to have the wide spectrum of activity as follows: RTI isolates, ofloxacin (92.2%-93.8% susceptible) > ciprofloxacin (89.5%-90.4%); SSTI isolates, ofloxacin (87.1%-93.6%) > ciprofloxacin (78.8%-90.4%); UTI isolates, ofloxacin (91.6%-92.5%) > norfloxacin (87.3%-91.7%) > ciprofloxacin (86.4%-89.7%); and genital tract isolates, ofloxacin (94.0%) > ciprofloxacin (85.4%) (Canada only). US strains resistant to ofloxacin were confirmed by reference laboratory tests. Confirmed ofloxacin resistance, other than among staphylococci or nonenteric bacilli, was rare. The species most often found to be resistant to both ofloxacin and ciprofloxacin were methicillin-resistant staphylococci, Acinetobacter spp., and Enterococcus spp. From these contributing US and Canadian laboratory studies, ofloxacin appears to have a balanced spectrum of potential clinical use (91.8% susceptible aerobic isolates), particularly against Gram-positive pathogens and some species resistant to ciprofloxacin. The combined overall isolate (12,241 isolates) rates of susceptibility for ciprofloxacin (four infection sites) and norfloxacin (UTI only) were 87.3% and 88.8%, respectively. Monitoring for increasing fluoroquinolone resistance should be considered, however, as greater use of drugs in this class develops.

The North American component (the United States and Canada) of an International Comparative MIC trial monitoring ofloxacin resistance

Common lots of reference MIC (minimum inhibitory concentration) method reagents were used to monitor ofloxacin, a newer fluoroquinolone, and 13 other drugs against 3200 recent clinical isolates in February-April 1992. Five medical centers in the United States and Canada contributed 640 strains per facility as follows: Escherichia coli, Staphylococcus aureus, coagulase-negative staphylococci, Klebsiella spp., and Pseudomonas aeruginosa (100 strains each); Streptococcus pneumoniae (40 strains); and Enterobacter cloacae, Serratia marcescens, Salmonella spp., Haemophilus influenzae, and Moraxella catarrhalis (20 strains each). Quality-control strains were processed concurrently, MICs recorded, and data processed at a common location. Selected ofloxacin-resistant isolates were retested at a reference laboratory to confirm resistances and determine cross-resistant patterns. Results indicate the following (a) fluoroquinolones were superior in usable spectrum of activity to other orally administered drugs (for example, cefaclor, cefixime, ampicillin, amoxicillin-clavulanate, minocycline, oxacillin, and trimethoprim-sulfamethoxazole); (b) ofloxacin and ciprofloxacin were generally equal to gentamicin and cefotaxime against commonly isolated Gram-negative pathogens; (c) fluoroquinolone resistance was rare among enteric bacilli, pneumococci (ciprofloxacin > ofloxacin), H. influenzae, and M. catarrhalis, but more common among oxacillin-resistant staphylococci and P. aeruginosa; (d) cross resistance was generally observed between ofloxacin and ciprofloxacin but was species or genus dependent; and (e) a new fluoroquinolone, levofloxacin, demonstrated promising activity against contemporary pathogens.

Postantibiotic effects of amikacin and ofloxacin on Mycobacterium fortuitum

A study of postantibiotic effects (PAE) in vitro of amikacin and ofloxacin on Mycobacterium fortuitum isolates from sternotomy wounds by use of the dilution method for drug removal showed that both drugs exhibited good bactericidal activities, with the PAE of amikacin lasting from 13.5 to 27.6 h and the PAE of ofloxacin lasting from 1.2 to 5.0 h. These laboratory results concur with our experience of the efficacy of once-daily dosing with these drugs in the treatment of infections caused by M. fortuitum. These data may have therapeutic implications in guiding the scheduling of the administration of drugs in these infections, which require a long duration of therapy.

Effect of seven fluoroquinolones on the determination of serum creatinine by the picric acid and enzymatic methods

OBJECTIVE

To investigate in vitro the interaction of seven fluoroquinolone antibiotics with the determination of serum creatinine by the picric acid and enzymatic methods.

DESIGN

This blind, in vitro study assayed duplicate serum samples for creatinine by the picric acid and enzymatic methods with averaged spiked concentrations of 2.71, 13.56, 27.12, and 108.47 mumol/L of ciprofloxacin, fleroxacin, lomefloxacin, ofloxacin, 1-ofloxacin, sparfloxacin, and temafloxacin. Cefoxitin (in concentrations of 233.9, 1169.6, 1754.4, and 2339.2 mumol/L) was used as a positive control for the picric acid assay.

SETTING

University-affiliated hospital, Department of Pharmaceutical Services and Clinical Chemistry section of the Department of Pathology.

MAIN OUTCOME MEASURE

The serum creatinine samples spiked with the seven substituted fluoroquinolones and cefoxitin were assayed by both the picric acid and enzymatic assays. Statistical analysis compared the spiked samples with blank serum by Student's t-test and concentration ranges were compared by analysis of variance. A statistically significant interference with serum creatinine was p < 0.05.

RESULTS

None of the substituted fluoroquinolones interfered significantly with the determination of serum creatinine by either method. Cefoxitin significantly interfered with the determination of serum creatinine by the picric acid method.

CONCLUSIONS

Fluoroquinolones do not interfere with the determination of serum creatinine by either the picric acid or enzymatic method.

Ofloxacin, a new broad-spectrum fluoroquinolone. Results from a Multicenter, National Comparative Activity Surveillance Study. The Ofloxacin Surveillance Group

Ofloxacin, a newer broad-spectrum fluoroquinolone, was evaluated against 6967 clinical isolates in a multicenter surveillance trial using a standardized disk diffusion method. Thirty-five geographically diverse laboratories contributed zone diameter results for two (ofloxacin and ciprofloxacin) to five (ofloxacin, ciprofloxacin, ampicillin, cefaclor, and cefixime) antimicrobial agents, depending on the site of infection. Ofloxacin was determined to have the widest spectrum of activity and potential empiric use (90.6%, range 87.1%-92.2%) for respiratory tract, urinary tract, and cutaneous infections. The spectrum was superior to ciprofloxacin (average 85.3% versus three sites), ampicillin (35.5%, respiratory tract), cefaclor (60.5%, respiratory tract), cefixime (60.9%, respiratory tract), and norfloxacin (87.3%, urinary tract). Strains resistant to ofloxacin (35 isolates, 0.5%) were confirmed by reference laboratory tests and cross resistance was observed among several current and investigational fluoroquinolone agents. The species most often found to be fluoroquinolone resistant among the Enterobacteriaceae were Klebsiella pneumoniae, Serratia marcescens, and Providencia spp. Monitoring for increasing fluoroquinolone resistance should be considered as greater use of drugs in this class develops. By these cited statistics, ofloxacin appears to have a broad and balanced spectrum of potential use, particularly against Gram-positive pathogens.