Intravenous piperacillin/tazobactam plus fluoroquinolone prophylaxis prior to prostate ultrasound biopsy reduces serious infectious complications and is cost effective

Infectious complications related to prostate ultrasound and biopsy have increased in the past decade with the emergence of increasing fluoroquinolone bacterial resistance. We investigated the addition of intravenous (iv) piperacillin/tazobactam immediately prior to prostate ultrasound and biopsy with standard fluoroquinolone prophylaxis to determine if it would decrease the incidence of serious infectious complications after prostate ultrasound and biopsy. Group 1 patients were a historic control of 197 patients who underwent prostate ultrasound and biopsy with standard fluoroquinolone prophylaxis. Group 2 patients, 104 patients, received standard fluoroquinolone prophylaxis and the addition of a single dose of iv piperacillin/tazobactam 30 minutes prior to prostate ultrasound and biopsy. There were ten serious bacterial infectious complications in group 1 patients. No patients in group 2 developed serious bacterial infections after prostate ultrasound and biopsy. There was approximately a 5% incidence of serious bacterial infection in group 1 patients. Subgroup analysis revealed an almost 2.5 times increased risk of infection in diabetes patients undergoing prostate ultrasound and biopsy. There was a 10% risk of serious bacterial infection in diabetics compared with a 3.8% risk group 1 nondiabetes patients. The addition of a single dose of iv piperacillin/tazobactam along with standard fluoroquinolone prophylaxis substantially reduces the risk of serious bacterial infection after prostate ultrasound and biopsy (P < 0.02).

The clinical impact of fluoroquinolone resistance in patients with E coli bacteremia

BACKGROUND

There are limited data on fluoroquinolone resistance and its impact on mortality in cases of Escherichia coli bloodstream infection (BSI).

OBJECTIVE

To determine risk factors for in-hospital mortality among patients with E coli BSIs.

DESIGN

A retrospective case-control study.

SETTING

A 1250-bed tertiary academic medical center.

PATIENTS

Patients with fluoroquinolone-resistant E coli BSI from January 1, 2000 through December 31, 2005 with 1:1 matched control patients with fluoroquinolone-sensitive E coli BSI. INDEPENDENT OUTCOME: In-hospital mortality.

RESULTS

A total of 93 cases and 93 control patients were included. Compared with control patients, cases were more likely to be admitted from a long-term care facility (35% vs. 9%; P < .001) and to have a hospital-acquired bacteremia (54% vs. 33%; P = .008). Crude mortality was 26% for cases and 8% for controls (P = .002). On univariate analysis, predictors for in-hospital mortality included female gender, admission from a long-term care facility, APACHE II score >10, Charlson comorbidity score >4, cardiac dysfunction, cirrhosis, renal dysfunction, treatment with corticosteroids, and a fluoroquinolone-resistant E coli bacteremia. On multivariate analysis, independent risk factors for in-hospital mortality were cirrhosis (adjusted odds ratio [aOR], 7.2; confidence interval [CI], 1.7-29.8; P = .007), cardiac dysfunction (aOR, 3.9; CI, 1.6-9.4; P = .003), and infection with a fluoroquinolone-resistant E coli isolate (aOR, 3.9; CI, 1.5-10.2; P = .005).

CONCLUSIONS

After controlling for severity of illness and multiple comorbidities only fluoroquinolone resistance, cirrhosis, and cardiac dysfunction independently predicted mortality in patients with E coli bacteremia.

Besifloxacin ophthalmic suspension: emerging evidence of its therapeutic value in bacterial conjunctivitis

Objective

To outline the pharmacodynamics, efficacy and safety of besifloxacin ophthalmic suspension 0.6% in the treatment of bacterial conjunctivitis.

Quality of Evidence

MEDLINE database was searched to review recent pharmacodynamic and clinical studies evaluating besifloxacin and comparing besifloxacin to other topical antibiotics for ophthalmic use. Findings were limited to full-text articles from clinical journals in the English language.

Main Message

Bacterial resistance is a common source for treatment failure in bacterial conjunctivis. Besifloxacin, a novel fourth generation synthetic fluoroquinolone is likely to show lower resistance rates due to its mechanism of action and its short-term use for ocular infections only (decreased systemic exposure). Besifloxacin displays improved pharmacodynamic properties compared to other commonly used fluoroquinolones and has shown to be efficacious and safe in clinical studies.

Conclusion

Besifloxacin ophthalmic suspension 0.6% provides safe and efficacious treatment for bacterial conjunctivitis. The factors leading to bacterial resistance are diminished, which allows besifloxacin to be a favorable treatment option.

The prevalence of fluoroquinolone resistance mechanisms in colonizing Escherichia coli isolates recovered from hospitalized patients

BACKGROUND

Fluoroquinolones are the most commonly prescribed antimicrobials. The epidemiology of fecal colonization with Escherichia coli demonstrating reduced susceptibility to fluoroquinolones remains unclear.

METHODS

During a 3-year period (15 September 2004 through 19 October 2007), all patients hospitalized for >3 days were approached for fecal sampling. All E. coli isolates with reduced susceptibility to fluoroquinolones (minimum inhibitory concentration [MIC] of levofloxacin, 0.125 microg/mL) were identified. We characterized gyrA and parC mutations and organic solvent tolerance. Isolates were compared using pulsed-field gel electrophoresis.

RESULTS

Of 353 patients colonized with E. coli demonstrating reduced fluoroquinolone susceptibility, 300 (85.0%) had 1 gyrA mutation, 161 (45.6%) had 1 parC mutation, and 171 (48.6%) demonstrated organic solvent tolerance. The mean numbers of total mutations (ie, gyrA and parC) for E. coli isolates with a levofloxacin MIC of 8 microg/mL versus <8.0 microg/mL were 2.70 and 0.82 (P < .001). Of the 136 E. coli isolates with a levofloxacin MIC of 8 microg/mL, 90 (66.2%) demonstrated a nalidixic acid MIC of 16 microg/mL. Significant differences were found over time in the proportion of E. coli isolates demonstrating gyrA mutation, parC mutation, and organic solvent tolerance. There was little evidence of clonal spread of isolates. Conclusions. Gastrointestinal tract colonization with E. coli demonstrating reduced susceptibility to levofloxacin is common. Although 40% of study isolates exhibited a levofloxacin MIC of <8 microg/mL (and would thus be missed by current Clinical and Laboratory Standards Institute breakpoints), nalidixic acid resistance may be a useful marker for detection of such isolates. Significant temporal changes occurred in the proportion of isolates exhibiting various resistance mechanisms.

Concentrations of besifloxacin, gatifloxacin, and moxifloxacin in human conjunctiva after topical ocular administration

PURPOSE

To evaluate the pharmacokinetic properties of besifloxacin, gatifloxacin, and moxifloxacin in the conjunctival tissue of healthy volunteers after topical application.

METHODS

One-hundred eight (108) subjects were randomly assigned to receive one drop of besifloxacin (0.6% suspension), gatifloxacin (0.3% solution), or moxifloxacin (0.5% solution) ophthalmic formulations in one eye prior to conjunctival biopsy. Conjunctival samples were taken from subjects at either 15 minutes, 30 minutes, 2 hours, 6 hours, 12 hours, or 24 hours after dosing.

RESULTS

All three fluoroquinolones reached a peak mean concentration 15 minutes after dosing. The mean concentrations of besifloxacin, gatifloxacin, and moxifloxacin at 15 minutes were 2.30 +/- 1.42 mug/g, 4.03 +/- 3.84 mug/g, and 10.7 +/- 5.89 mug/g, respectively. Concentrations decreased with each subsequent time point. At 24 hours after dosing, concentrations of besifloxacin were measurable in 4 of 6 subjects, compared with 3 of 6 subjects for gatifloxacin and 2 of 6 subjects for moxifloxacin. Besifloxacin had the greatest mean residence time (4.7 hours) in the conjunctival tissue. With regard to methicillin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis, besifloxacin had the greatest area-under-the-curve (AUC) to MIC(90) ratio. Nine percent (9%) of study subjects (N = 7) experienced a transient reduction in visual acuity.

CONCLUSION

All three fluoroquinolones were well tolerated and reached levels in the conjunctiva above the MIC(90)s of methicillin-sensitive S. aureus and S. epidermidis for at least 2 hours.

Intraocular penetration of sequentially instilled topical moxifloxacin, gatifloxacin, and levofloxacin

Purpose:

The objective of the study was to compare the intraocular penetration levels of the newer fluoroquinolones, moxifloxacin, gatifloxacin, and levofloxacin in the rabbit’s cornea, aqueous humor, and conjunctiva after topical instillation.

Methods:

0.5% moxifloxacin, 0.3% gatifloxacin, and 0.5% levofloxacin were instilled in random sequence in both eyes of nine New Zealand White rabbits at two-minute intervals. Instillation was repeated every 15 minutes for a total of three drops of each fluoroquinolone per eye. Three additional animals had only moxifloxacin instilled bilaterally using the same schedule. Sixty minutes after the final instillation, the rabbits were sacrificed for determination of corneal, aqueous humor, and conjunctival fluoroquinolone concentrations using high-performance liquid chromatography.

Results:

Moxifloxacin achieved significantly higher concentrations than levofloxacin and gatifloxacin in the cornea (P = 0.0102 and P = 0.0006, respectively), aqueous humor (P = 0.0015 and P < 0.0001, respectively), and conjunctiva (P = 0.0191 and P = 0.0236, respectively).

Conclusions:

0.5% moxifloxacin eyedrops provided superior intraocular penetration in rabbits’ eyes compared with the two other fluoroquinolones, 0.5% levofloxacin and 0.3% gatifloxacin.

Tuberculosis pharmacotherapy: strategies to optimize patient care

INTRODUCTION

The treatment of tuberculosis (TB) is a mature discipline, with more than 60 years of clinical experience accrued across the globe. The requisite Multi-drug treatment of drug-susceptible TB, however, lasts 6 months and has never been optimized according to current standards. Multi-drug resistant TB and TB in individuals coinfected with HIV present additional treatment challenges.

OBJECTIVE

This article reviews the role that existing drugs and new compounds could have in shortening or improving treatment for TB. The key to treatment shortening seems to be sterilizing activity, or the ability of drugs to kill mycobacteria that persist after the initial days of multi-drug treatment.

RESULTS

Among existing anti-TB drugs, the rifamycins hold the greatest potential for shortening treatment and improving outcomes, in both HIV-infected and HIV-uninfected populations, without dramatic increases in toxicity. Clinical studies underway or being planned, are supported by in vitro , animal and human evidence of increased sterilizing activity--without significant increases in toxicity--at elevated daily doses. Fluoroquinolones also seem to have significant sterilizing activity. At present, at least two class members are being evaluated for treatment shortening with different combinations of first-line drugs. However, in light of apparent rapid selection for fluoroquinolone-resistant mutants, relative frequency of serious adverse events and a perceived need to 'reserve' fluoroquinolones for the treatment of drug-resistant TB, their exact role in TB treatment remains to be determined. Other possible improvements may come from inhaled delivery or split dosing (linezolid) of anti-TB drugs for which toxicity (ethionamide) or lack of absorption (aminoglycosides and polypeptides) precludes delivery of maximally effective, oral doses, once daily. New classes of drugs with novel mechanisms of action, nitroimidazopyrans and a diarylquinoline, among others, may soon provide opportunities for improving treatment of drug-resistant TB or shortening treatment of drug-susceptible TB.

CONCLUSION

More potential options for improved TB treatment currently exist than at any other time in the last 30 years. The challenge in TB pharmacotherapy is to devise well-tolerated, efficacious, short-duration regimens that can be used successfully against drug-resistant and drug-resistant TB in a heterogeneous population of patients.

Assessing sensitivity to antibacterial topoisomerase II inhibitors

Both prokaryotes and eukaryotes have two major classes of topoisomerases that make transient single- or double-strand cuts in DNA. While these enzymes play critical roles in cellular processes, they are also important targets of therapeutic agents. This unit describes assays to use in characterizing topoisomerase II-targeting agents in vitro and in bacterial cells. It provides protocols for characterizing the action of small molecules against bacterial type II topoisomerases in vitro and the in vivo effects of putative topoisomerase II-targeting antibiotics, as well as for measuring trapped enzyme/DNA covalent complexes, the major cytotoxic lesion induced by fluoroquinolones.

Skin and skin structure infections: treatment with newer generation fluoroquinolones

Skin and skin structure infections (SSSI) are an emerging issue in healthcare. They are responsible for increasing heathcare utilization, both in hospitalizations and intravenous antibiotic use. SSSI are caused by an evolving variety of pathogens, including Gram-positive, Gram-negative, and anaerobic bacteria. In combination with mounting resistance patterns, this diverse range of bacteria mandate empiric broad-spectrum antibiotic coverage. Historically, cephalosporins and penicillins have been the mainstay of treatment, but recent data suggest newer generation fluoroquinolones are being used with increasing frequency. In 2005, moxifloxacin joined gatifloxacin and levofloxacin as newer generation fluoroquionolones with Food and Drug Administration indications for SSSIs. Even within this group there exist subtle differences that impact optimal management. This paper offers the clinician a comparative review of the antimicrobial spectrum, pharmacodynamics, pharmacokinetics, and clinical efficacy data to support the appropriate use of fluoroquinolones in SSSIs.

Lens concentration of ofloxacin and lomefloxacin in an experimental endophthalmitis model

Abstract.

BACKGROUND

Bacterial endophthalmitis is a serious complication of ocular surgery and penetrating trauma. The primary causative organisms are strains of Staphylococcus aureus and Staphylococcus epidermidis. Fluoroquinolones are widely used to treat endophthalmitis. There are a few studies on the penetration of fluoroquinolones into the lens in inflamed eyes. A literature search did not identify any data regarding penetration of topical ofloxacin into the lens in normal and inflamed eyes.

OBJECTIVE

The aim of this study was to determine the penetration of topical ofloxacin and lomefloxacin into the lens in a rabbit endophthalmitis model.

METHODS

New Zealand white rabbits were randomly divided into 2 groups. The left eyes were infected with an intravitreal inoculation of S aureus. The right eyes were used as a noninoculated control. Groups 1 and 2 received topical ofloxacin and lomefloxacin treatment, respectively, 24 hours after the inoculation. Two drops of the study drugs were instilled in the eyes every 30 minutes for 3 hours and then every 60 minutes for 3 hours. Lens samples were obtained 30 minutes after the last ofloxacin or lomefloxacin drops were administered. High-performance liquid chromatography was used to determine the fluoroquinolone concentration.

RESULTS

Ten rabbits were equally divided into the 2 treatment groups. There was no significant difference in mean (SD) lens concentrations between the control and inoculated eyes in either treatment group-ofloxacin (0.26 [0.32] μg/mL vs 0.11 [0.05] μg/mL, respectively) and lomefloxacin (0.50 [0.87] μg/mL vs 0.12 [0.08] μg/mL, respectively).

CONCLUSION

The results of this small experimental study found that topical ofloxacin and lomefloxacin can accumulate in the crystalline lens after installation. Inflammation did not affect the penetration of ofloxacin or lomefloxacin into the lens.

Life-threatening infantile diarrhea from fluoroquinolone-resistant Salmonella enterica typhimurium with mutations in both gyrA and parC

Salmonella Typhimurium DT12, isolated from a 35-day-old infant with diarrhea, was highly resistant to ampicillin, tetracycline, chloramphenicol, streptomycin, gentamycin, sulfamethoxazole/trimethoprim, nalidixic acid, and fluoroquinolones. The patient responded to antibiotic therapy with fosfomycin. Multidrug-resistance may become prevalent in Salmonella infections in Japan, as shown in this first case of a patient infected with fluoroquinolone-resistant Salmonella.

Fluoroquinolone resistance in Campylobacter jejuni isolates in travelers returning to Finland: association of ciprofloxacin resistance to travel destination

Ciprofloxacin resistance was analyzed in 354 Campylobacter jejuni isolates collected during two study periods (1995-1997 and 1998-2000) from travelers returning to Finland. The increase in resistance between the two periods was significant among all isolates (40% vs. 60%; p<0.01), as well as among those from Asia alone (45% vs. 72%; p<0.01).

Accumulation of ciprofloxacin and minocycline by cultured human gingival fibroblasts

Through a mechanism that is unclear, systemic fluoroquinolones and tetracyclines can attain higher levels in gingival fluid than in blood. We hypothesized that gingival fibroblasts take up and accumulate these agents, thereby enhancing their redistribution to the gingiva. Using fluorescence to monitor transport activity, we characterized the accumulation of fluoroquinolones and tetracyclines in cultured human gingival fibroblast monolayers. Both were transported in a concentrative, temperature-dependent, and saturable manner. Fibroblasts transported ciprofloxacin and minocycline with K(m) values of 200 and 108 micro g/mL, respectively, at maximum velocities of 4.62 and 14.2 ng/min/ micro g cell protein, respectively. For both agents, transport was most efficient at pH 7.2 and less efficient at pH 6.2 and 8.2. At steady state, the cellular/extracellular concentration ratio was > 8 for ciprofloxacin and > 60 for minocycline. Thus, gingival fibroblasts possess active transporters that could potentially contribute to the relatively high levels these agents attain in gingival fluid.

An in vitro model of ciprofloxacin and minocycline transport by oral epithelial cells

BACKGROUND

Fluoroquinolones and tetracyclines can penetrate epithelial cells, but the mechanism by which they cross the plasma membrane is unclear. In this study, a cell line derived from oral epithelium was used as a model to demonstrate a role for active transport.

METHODS

Transport of ciprofloxacin and minocycline by confluent cell monolayers was assayed by measuring the increase in cell-associated fluorescence.

RESULTS

Uptake of both agents was saturable and was inhibited at low temperatures. At 37 degrees C, the cells transported ciprofloxacin and minocycline with Km values of 351 and 133 microg/ml, respectively, and maximum velocities of 5.11 and 13.4 ng/min/microg cell protein, respectively. When ciprofloxacin and minocycline were removed from the extracellular medium, the intracellular levels of both agents decreased. Ciprofloxacin efflux from loaded cells occurred more rapidly than with minocycline. Cells accumulated intracellular drug levels that were at least 8-fold higher than extracellular levels for ciprofloxacin and at least 40-fold higher for minocycline. Transport of ciprofloxacin and minocycline was significantly influenced by pH and was most favorable at pH 7.7 and 7.2, respectively. While ciprofloxacin transport was Na+ independent, minocycline transport was strongly inhibited when sodium in the medium was replaced with choline. Transport of both agents was inhibited by a variety of organic cations, but the pattern of inhibition was different. Papaverine, phenylephrine, and doxycycline competitively inhibited minocycline transport, but inhibited ciprofloxacin transport by a non-competitive mechanism.

CONCLUSIONS

Epithelial cells take up ciprofloxacin and minocycline via different active transport systems. These transporters may play an important role in enhancing the effectiveness of these agents against invasive pathogens.

Multiple pathways for fluoroquinolone secretion by human intestinal epithelial (Caco-2) cells

1. Human intestinal epithelial Caco-2 cells, T84 cells, and MDCKII cells transfected with human MDR1, were used to investigate the mechanistic basis of transintestinal fluoroquinolone secretion. 2. The fluoroquinolone grepafloxacin was secreted across Caco-2 monolayers by a saturable process (V(max)=16.9 +/- 3.4 nmol.cm(-2).h(-1)). Net secretion was reduced by 2-deoxyglucose/azide treatment to reduce intracellular ATP. 3. Grepafloxacin inhibited [(14)C]-ciprofloxacin (100 microM) secretion across Caco-2 monolayers (K(0.5)=0.8 mM), and concurrently increased the cellular accumulation of ciprofloxacin from the basal medium, indicating inhibition of export across the apical membrane. 4. The unconjugated bile acid, cholic acid, was secreted across Caco-2 monolayers, and this secretion was sensitive to inhibition by the MRP-selective inhibitor MK-571, suggesting MRP2 involvement. Secretion of cholic acid (10 microM) across the apical membrane was also inhibited by grepafloxacin (K(0.5)=0.3 mM), but not by ciprofloxacin. 5. In MDCKII-MDR1 monolayers, net secretion of grepafloxacin was increased by 3.5 fold compared with untransfected controls. Neither ciprofloxacin nor cholic acid showed net secretion in either MDCKII or MDCKII-MDR1 monolayers, showing that in contrast to grepafloxacin, neither are substrates for MDR1. 6. In T84 monolayers, which express MDR1 but not MRP2, neither ciprofloxacin nor cholic acid was secreted, whilst the V(max) for grepafloxacin secretion was lower than in Caco-2 cells, which express both MDR1 and MRP2. 7. In conclusion, the transepithelial secretion of grepafloxacin is mediated by both MRP2 and MDR1, whereas ciprofloxacin is a substrate for neither. Grepafloxacin also competes for the ciprofloxacin-sensitive pathway, which remains to be elucidated.