Trovafloxacin compared with levofloxacin, ofloxacin, ciprofloxacin, azithromycin and clarithromycin against unusual aerobic and anaerobic human and animal bite-wound pathogens

A Review of New Fluoroquinolones : Focus on their Use in Respiratory Tract Infections

The new respiratory fluoroquinolones (gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin, and on the horizon, garenoxacin) offer many improved qualities over older agents such as ciprofloxacin. These include retaining excellent activity against Gram-negative bacilli, with improved Gram-positive activity (including Streptococcus pneumoniae and Staphylococcus aureus). In addition, gatifloxacin, moxifloxacin and garenoxacin all demonstrate increased anaerobic activity (including activity against Bacteroides fragilis). The new fluoroquinolones possess greater bioavailability and longer serum half-lives compared with ciprofloxacin. The new fluoroquinolones allow for once-daily administration, which may improve patient adherence. The high bioavailability allows for rapid step down from intravenous administration to oral therapy, minimizing unnecessary hospitalization, which may decrease costs and improve quality of life of patients. Clinical trials involving the treatment of community-acquired respiratory infections (acute exacerbations of chronic bronchitis, acute sinusitis, and community-acquired pneumonia) demonstrate high bacterial eradication rates and clinical cure rates. In the treatment of community-acquired respiratory tract infections, the various new fluoroquinolones appear to be comparable to each other, but may be more effective than macrolide or cephalosporin-based regimens. However, additional data are required before it can be emphatically stated that the new fluoroquinolones as a class are responsible for better outcomes than comparators in community-acquired respiratory infections. Gemifloxacin (except for higher rates of hypersensitivity), levofloxacin, and moxifloxacin have relatively mild adverse effects that are more or less comparable to ciprofloxacin. In our opinion, gatifloxacin should not be used, due to glucose alterations which may be serious. Although all new fluoroquinolones react with metal ion-containing drugs (antacids), other drug interactions are relatively mild compared with ciprofloxacin. The new fluoroquinolones gatifloxacin, gemifloxacin, levofloxacin, and moxifloxacin have much to offer in terms of bacterial eradication, including activity against resistant respiratory pathogens such as penicillin-resistant, macrolide-resistant, and multidrug-resistant S. pneumoniae. However, ciprofloxacin-resistant organisms, including ciprofloxacin-resistant S. pneumoniae, are becoming more prevalent, thus prudent use must be exercised when prescribing these valuable agents.

Comparative activity of pradofloxacin against anaerobic bacteria isolated from dogs and cats

OBJECTIVES

To compare the intrinsic activity of pradofloxacin, a new fluoroquinolone developed for use in veterinary medicine, with other fluoroquinolones, against anaerobic bacteria isolated from dogs and cats.

METHODS

One hundred and forty-one anaerobes were isolated from dogs and cats and comparative MICs of pradofloxacin, marbofloxacin, enrofloxacin, difloxacin and ibafloxacin were determined according to standardized agar dilution methodology.

RESULTS

Pradofloxacin exerted the greatest antibacterial activity followed by marbofloxacin, enrofloxacin, difloxacin and ibafloxacin. Based on the distinctly lower MIC(50), MIC(90) and mode MIC values, pradofloxacin exhibited a higher in vitro activity than any of the comparator fluoroquinolones.

CONCLUSIONS

Pradofloxacin, a novel third-generation fluoroquinolone, has broad-spectrum anti-anaerobe activity and offers utility as single-drug therapy for mixed aerobic/anaerobic infections.

Thigh abscess caused by Eikenella corrodens and Streptococcus intermedius: A case report

A 35-year-old Chinese female has a large thigh abscess without a clear source. No underlying diseases were revealed in the patient. The combination of clindamycin and cefazolin or vancomycin was administered but without a clinical response. Eikenella corrodens and Streptococcus intermedius were isolated from puncture drainage. Then, ceftriaxone was administered and a surgery of incision and further draining was carried. Eventually, the patient recovered. To our knowledge, this is the first case of thigh abscess in a previous healthy adult.

Effects of gyrase mutation on the growth kinetics of ciprofloxacin-resistant strains of Clostridium perfringens

To investigate the effect of gyrA mutation on resistance of Clostridium perfringens to fluoroquinolones, a ciprofloxacin-resistant mutant was developed. The mutant had a single substitution in gyrA at position 87 (Asp to Tyr) and no additional mutations in gyrB, parC or parE. The MIC values of gatifloxacin and ciprofloxacin for this strain were 16 and 32-fold higher than those for the wild type, which were 0.125 and 0.250 microg/mL, respectively. The resistant mutant grew equally well in the presence or absence of 5 microg/mL of ciprofloxacin or 1 microg/mL of gatifloxacin and grew to lower cell densities with up to 30 microg/mL of ciprofloxacin or 5 microg/mL of gatifloxacin. Higher concentrations of fluoroquinolones resulted in increases in the time required to reach the end of the exponential phase and in lower cell densities at the end. The efflux pump inhibitor reserpine did not affect susceptibility to fluoroquinolones. The substitution of Asp 87 to Tyr in gyrA may have protected C. perfringens from low concentrations of ciprofloxacin and gatifloxacin and enabled survival and growth at higher concentrations.

Genetic determinant of intrinsic quinolone resistance in Fusobacterium canifelinum

Fourteen fluoroquinolone-resistant fusobacterial strains, originating from cats or dogs, were characterized by sequencing of the 16S-23S and 16S rRNA genes and DNA-DNA hybridization and were described as a new species, Fusobacterium canifelinum. All of the strains are intrinsically resistant (MIC, >4 g/ml) to levofloxacin and other fluoroquinolones. Compared to the quinolone resistance-determining region (gyrA) of the susceptible relative F. nucleatum, we found that Ser79 was replaced with leucine and Gly83 was replaced with arginine.

North American wild mammalian injuries

Wild animal injuries are distinct from other injuries sustained by humans; tearing, cutting, penetrating, and crushing injuries are sometimes combined with falls and large animal forces causing blunt trauma. Bites from attacking animals may cause local infection, and wounds are potentially contaminated with a variety of pathogens. In addition, animals can transmit systemic diseases, many of which induce substantial morbidity and mortality. To compound the problem, many animal attacks occur in remote or wilderness areas and involve substantial delays in the time to notification, rescue, and presentation to definitive care. This article discusses attacks by the most common North American wild mammals.

Levofloxacin: a review of its use in the treatment of bacterial infections in the United States

Levofloxacin (Levaquin) is a fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and Gram-negative bacteria and atypical respiratory pathogens. It is active against both penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae. The prevalence of S. pneumoniae resistance to levofloxacin is <1% overall in the US.A number of randomised comparative trials in the US have demonstrated the efficacy of levofloxacin in the treatment of infections of the respiratory tract, genitourinary tract, skin and skin structures. Sequential intravenous to oral levofloxacin 750mg once daily for 7-14 days was as effective in the treatment of nosocomial pneumonia as intravenous imipenem/cilastatin 500-1000mg every 6-8 hours followed by oral ciprofloxacin 750mg twice daily in one study. In patients with mild to severe community-acquired pneumonia (CAP), intravenous and/or oral levofloxacin 500mg once daily for 7-14 days achieved clinical and bacteriological response rates similar to those with comparator agents, including amoxicillin/clavulanic acid, clarithromycin, azithromycin, ceftriaxone and/or cefuroxime axetil and gatifloxacin. A recent study indicates that intravenous or oral levofloxacin 750mg once daily for 5 days is as effective as 500mg once daily for 10 days, in the treatment of mild to severe CAP. Exacerbations of chronic bronchitis and acute maxillary sinusitis respond well to treatment with oral levofloxacin 500mg once daily for 7 and 10-14 days, respectively. Oral levofloxacin was as effective as ofloxacin in uncomplicated urinary tract infections and ciprofloxacin or lomefloxacin in complicated urinary tract infections. In men with chronic bacterial prostatitis treated for 28 days, oral levofloxacin 500mg once daily achieved similar clinical and bacteriological response rates to oral ciprofloxacin 500mg twice daily. Uncomplicated skin infections responded well to oral levofloxacin 500mg once daily for 7-10 days, while in complicated skin infections intravenous and/or oral levofloxacin 750mg for 7-14 days was at least as effective as intravenous ticarcillin/clavulanic acid (+/- switch to oral amoxicillin/clavulanic acid) administered for the same duration. Levofloxacin is generally well tolerated, with the most frequently reported adverse events being nausea and diarrhoea; in comparison with some other quinolones it has a low photosensitising potential and clinically significant cardiac and hepatic adverse events are rare.

CONCLUSION

Levofloxacin is a broad-spectrum antibacterial agent with activity against a range of Gram-positive and Gram-negative bacteria and atypical organisms. It provides clinical and bacteriological efficacy in a range of infections, including those caused by both penicillin-susceptible and -resistant strains of S. pneumoniae. Levofloxacin is well tolerated, and is associated with few of the phototoxic, cardiac or hepatic adverse events seen with some other quinolones. It also has a pharmacokinetic profile that is compatible with once-daily administration and allows for sequential intravenous to oral therapy. The recent approvals in the US for use in the treatment of nosocomial pneumonia and chronic bacterial prostatitis, and the introduction of a short-course, high-dose regimen for use in CAP, further extend the role of levofloxacin in treating bacterial infections.

Bite Wound Infections

Patients with mammalian bite wounds account for hundreds of thousands of emergency department, urgent care center, and physician office visits in the United States each year. The types of wounds encountered by physicians range from insignificant scratches to life-threatening neck and facial injuries. Infectious complications of bite wounds are common, and the consequences of these infections are significant and sometimes disabling. This article reviews the infectious complications of cat, dog, and human bite wounds. The prevention of tetanus and rabies virus infection, the appropriate antimicrobial treatment of bacterial infections, and the frequent need for surgical consultation and intervention are emphasized.

In vitro activities of tigecycline (GAR-936) and 12 other antimicrobial agents against 90 Eikenella corrodens clinical isolates

The activity of tigecycline was compared with those of other antimicrobials against 90 isolates of Eikenella corrodens. The MIC at which 90% of the isolates were inhibited was 2 micro g/ml for tigecycline and 1, </=0.5/0.25, 0.5, </=0.12, </=2, and 0.5 micro g/ml for ampicillin, amoxicillin-clavulanate, cefotaxime, imipenem, chloramphenicol, and ciprofloxacin, respectively.

The role of quinolones in abdominal surgery

The quinolone antibiotics have been a major advance for the treatment of various types of infections. These agents have generally good safety profiles, broad-spectrum activity, and favorable pharmacokinetics. In addition, several of these antibiotics are available in both intravenous and oral formulations, which allows for sequential therapy resulting in potential cost savings. However, patients can develop serious central nervous system side effects (seizures) and phototoxicity. In addition, the bioavailability of agents in this class can be reduced by coadministration with cations, such as magnesium, aluminum, calcium, and iron, which may make bioavailability unpredictable in patients. Although older quinolones such as ciprofloxacin were effective as prophylactic agents for biliary procedures and colorectal surgery and for the treatment of intra-abdominal infections, the use of these older quinolones was limited by the development of resistant organisms. In addition, because these agents had poor activity against anaerobes such as Bacteroides fragilis, the agents had to be combined with an antianaerobic agent, such as metronidazole, when anaerobic coverage was required. Recently, a new quinolone, trovafloxacin, has become available. Trovafloxacin has demonstrated increased activity against anaerobes in animal and human studies. However, the clinical profile of trovafloxacin for abdominal infections has not been fully demonstrated, and there is some concern that its activity against aerobic gram-negative bacilli, especially Pseudomonas aeruginosa, may not equal that of ciprofloxacin. Moreover, the safety profile of trovafloxacin is disadvantageous owing to reports of severe hepatic toxicity.

In vitro activities of garenoxacin (BMS-284756) against 170 clinical isolates of nine Pasteurella species

The in vitro susceptibilities of 170 clinical isolates plus 12 American Type Culture Collection strains of Pasteurella species comprising nine species and three Pasteurella multocida subspecies were studied by an agar dilution method. Garenoxacin (BMS-284756), a new des-fluoro(6) quinolone, was active at 90% of the strains susceptible to Collapse

Key Words Collapse

MESH Headings

• Anti-Infective Agents/pharmacology
• Bites and Stings/microbiology
• Culture Media
• Drug Resistance, Bacterial
• Fluoroquinolones
• Humans
• Indoles
• Microbial Sensitivity Tests
• Pasteurella/drug effects
• Pasteurella Infections/microbiology
• Quinolones
• United States

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Grants Collapse

Affiliation(s)

Ellie J C Goldstein R. M. Alden Research Laboratory, Santa Monica-University of California, Los Angeles, Medical Center, Santa Monica, California 90404, USA.
Diane M Citron
C Vreni Merriam
Yumi A Warren
Kerin L Tyrrell
Helen T Fernandez

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In vitro activities of a new des-fluoroquinolone, BMS 284756, and seven other antimicrobial agents against 151 isolates of Eikenella corrodens

The des-fluoroquinolone BMS 284756 was active in vitro against all 151 clinical strains of Eikenella corrodens at a MIC of < or = 0.25 microg/ml and was comparable in activity to moxifloxacin and levofloxacin. The MIC at which 90% of the isolates were inhibited by penicillin G was 2 microg/ml; MICs for 8.6% of the strains (13 of 151) were > or = 4 microg/ml, including for two beta-lactamase-producing isolates. Amoxicillin-clavulanate and ampicillin-sulbactam inhibited all strains at a MIC of < or = 1 microg/ml.

Penetration of levofloxacin into skin tissue after oral administration of multiple 750 mg once-daily doses

OBJECTIVE

To probe the pharmacokinetic basis for the use of levofloxacin for complicated skin and skin-structure infections (SSSIs) at a once-daily dosage of 750 mg by investigating its penetration into skin tissue.

METHOD

Ten healthy volunteers were administered three oral, once-daily 750 mg doses of levofloxacin, and levofloxacin concentrations were subsequently measured over time (0.5-24 h) in skin-punch biopsy tissue and plasma.

RESULTS

Skin tissue concentrations consistently exceeded those in plasma at every time point, with tissue/plasma ratios of 1.37 +/- 0.81 for peak concentration and 1.97 +/- 0.35 for area under the concentration versus time curve. Three of the ten subjects reported treatment-emergent adverse events (AEs) that were considered unrelated to treatment. An 11th subject who had enrolled in the study withdrew after AEs of mild severity that were possibly related to the study drug.

CONCLUSION

The results support the clinical usage of levofloxacin 750 mg once-daily for complicated SSSIs.

A critical review of the fluoroquinolones: focus on respiratory infections

The new fluoroquinolones (clinafloxacin, gatifloxacin, gemifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin) offer excellent activity against Gram-negative bacilli and improved Gram-positive activity (e.g. against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Ciprofloxacin still maintains the best in vitro activity against Pseudomonas aeruginosa. Clinafloxacin, gatifloxacin, moxifloxacin, sitafloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (e.g. Bacteroides fragilis) versus ciprofloxacin. All of the new fluoroquinolones display excellent bioavailability and have longer serum half-lives than ciprofloxacin allowing for once daily dose administration. Clinical trials comparing the new fluoroquinolones to each other or to standard therapy have demonstrated good efficacy in a variety of community-acquired respiratory infections (e.g. pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis). Limited data suggest that the new fluoroquinolones as a class may lead to better outcomes in community-acquired pneumonia and acute exacerbations of chronic bronchitis versus comparators. Several of these agents have either been withdrawn from the market, had their use severely restricted because of adverse effects (clinafloxacin because of phototoxicity and hypoglycaemia; grepafloxacin because of prolongation of the QTc and resultant torsades de pointes; sparfloxacin because of phototoxicity; and trovafloxacin because of hepatotoxicity), or were discontinued during developmental phases. The remaining fluoroquinolones such as gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin have adverse effect profiles similar to ciprofloxacin. Extensive post-marketing safety surveillance data (as are available with ciprofloxacin and levofloxacin) are required for all new fluoroquinolones before safety can be definitively established. Drug interactions are limited; however, all fluoroquinolones interact with metal ion containing drugs (eg. antacids). The new fluoroquinolones (gatifloxacin, gemifloxacin, levofloxacin and moxifloxacin) offer several advantages over ciprofloxacin and are emerging as important therapeutic agents in the treatment of community-acquired respiratory infections. Their broad spectrum of activity which includes respiratory pathogens such as penicillin and macrolide resistant S. pneumoniae, favourable pharmacokinetic parameters, good bacteriological and clinical efficacy will lead to growing use of these agents in the treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute sinusitis. These agents may result in cost savings especially in situations where, because of their potent broad-spectrum activity and excellent bioavailability, they may be used orally in place of intravenous antibacterials. Prudent use of the new fluoroquinolones will be required to minimise the development of resistance to these agents.

In vitro activities of the des-fluoro(6) Quinolone BMS-284756 against aerobic and anaerobic pathogens isolated from skin and soft tissue animal and human bite wound infections

BMS-284756, a new des-fluoro(6) quinolone, was very active against 240 aerobic and 180 anaerobic isolates from bite victims. It inhibited 403 of 420 (96%) isolates, including those of Moraxella spp., CDC group EF-4, and Eikenella corrodens at < or = 2 microg/ml and those of all Pasteurella spp. and Bergeyella zoohelcum at < or = 0.015 microg/ml. Fusobacterium russii and 6 of 11 Fusobacterium nucleatum isolates of animal bite origin were resistant, but isolates of human bite origin were susceptible, which suggests that they were of a different subspecies.

Ofloxacin-loaded liposomes: in vitro activity and drug accumulation in bacteria

Different ofloxacin-loaded unilamellar vesicles were prepared by the extrusion technique, and their antimicrobial activities were determined in comparison to those of the free drug by means of MIC determinations with both American Type Culture Collection standards and wild-type bacterial strains (six strains of Enterococcus faecalis, seven strains of Escherichia coli, six strains of Staphylococcus aureus, and six strains of Pseudomonas aeruginosa). The accumulation of ofloxacin and liposome-ofloxacin was measured by determining the amount of the drug inside the bacteria as a function of time. Encapsulated fluoroquinolone yielded MICs which were at least twofold lower than those obtained with the free drug. In particular, liposomes made up of dimyristoylphosphatidylcholine-cholesterol-dipalmitoylphosphatidylser ine and dimyristoylphosphatidylcholine-cholesterol-dihexadecylphosphate (4:3:4 molar ratio) provided the best improvement in antimicrobial activity against the various bacterial strains investigated. The liposome formulation produced higher intracellular fluoroquinolone concentrations than those achieved simultaneously with the free drug in both E. coli and P. aeruginosa.

Levofloxacin

Levofloxacin (DR-3355, Daiichi) is a new fluoroquinolone antibiotic which is the active isomer of ofloxacin (DL-8280, Daiichi). By removing the inactive isomer, the in vitro activity of levofloxacin is 8-128 times higher than that of ofloxacin. This means that bacterial species, which have borderline susceptibility to ofloxacin and other first generation fluoroquinolones (e.g., pneumococci and organisms causing atypical pneumonia), are considerably more sensitive to levofloxacin. The pharmacokinetics of levofloxacin, which is available for both oral and i.v. administration, are characterised by a very high bioavailability, low (30-40%) protein binding, high tissue concentrations and elimination via the kidneys with minimal liver metabolism. As a consequence of the low degree of metabolism, levofloxacin does not interact with other drugs to any major extent. The safety and efficacy of levofloxacin are well documented in lower respiratory tract infections, skin and soft tissue infections, and urinary tract infections. The safety profile seems advantageous and the risks of phototoxicity, CNS toxicity and cardiac reactions (prolongation of QT-time) are low. Serious liver toxicity, leading to the recent withdrawal of trovafloxacin, has not been a problem in levofloxacin studies. Levofloxacin is a valuable addition to the group of fluoroquinolone antibiotics.

Activity of gatifloxacin compared to those of five other quinolones versus aerobic and anaerobic isolates from skin and soft tissue samples of human and animal bite wound infections

The activity of gatifloxacin against 308 aerobes and 112 anaerobes isolated from bite wound infections was studied. Gatifloxacin was active at </=0.016 microg/ml against all 148 Pasteurella isolates (eight species and three subspecies) tested and all other aerobes tested, including Actinobacillus-Haemophilus spp., Eikenella corrodens, Neisseria weaveri, Weeksella zoohelcum, staphylococci, and streptococci. Fusobacteria were sometimes resistant. Gatifloxacin MICs at which 90% of the isolates were inhibited were 0. 125 microg/ml against Bacteroides tectum and Prevotella spp., 0.25 microg/ml against Porphyromonas spp., and 0.5 microg/ml against peptostreptococci.

Linezolid activity compared to those of selected macrolides and other agents against aerobic and anaerobic pathogens isolated from soft tissue bite infections in humans

Linezolid was tested against 420 aerobes and anaerobes, including 148 Pasteurella isolates, by an agar dilution method. Linezolid was active against all Pasteurella multocida subsp. multocida and P. multocida subsp. septica isolates and most Pasteurella canis, Pasteurella dagmatis, and Pasteurella stomatis isolates. The MIC was </=2 microg/ml for staphylococci, streptococci, EF-4b, Weeksella zoohelcum, Fusobacterium nucleatum, other fusobacteria, Porphyromonas spp., Prevotella spp., peptostreptococci, and almost all Bacteroides tectum isolates.

Bacteriologic analysis of infected dog and cat bites. Emergency Medicine Animal Bite Infection Study Group

BACKGROUND AND METHODS

To define better the bacteria responsible for infections of dog and cat bites, we conducted a prospective study at 18 emergency departments. To be eligible for enrollment, patients had to meet one of three major criteria for infection of a bite wound (fever, abscess, and lymphangitis) or four of five minor criteria (wound-associated erythema, tenderness at the wound site, swelling at the site, purulent drainage, and leukocytosis). Wound specimens were cultured for aerobic and anaerobic bacteria at a research microbiology laboratory and, in some cases, at local hospital laboratories.

RESULTS

The infected wounds of 50 patients with dog bites and 57 patients with cat bites yielded a median of 5 bacterial isolates per culture (range, 0 to 16) at the reference laboratory. Significantly more isolates grew at the reference laboratory than at the local laboratories (median, 1; range, 0 to 5; P<0.001). Aerobes and anaerobes were isolated from 56 percent of the wounds, aerobes alone from 36 percent, and anaerobes alone from 1 percent; 7 percent of cultures had no growth. Pasteurella species were the most frequent isolates from both dog bites (50 percent) and cat bites (75 percent). Pasteurella canis was the most common isolate of dog bites, and Past. multocida subspecies multocida and septica were the most common isolates of cat bites. Other common aerobes included streptococci, staphylococci, moraxella, and neisseria. Common anaerobes included fusobacterium, bacteroides, porphyromonas, and prevotella. Isolates not previously identified as human pathogens included Reimerella anatipestifer from two cat bites and Bacteroides tectum, Prevotella heparinolytica, and several porphyromonas species from dog and cat bites. Erysipelothrix rhusiopathiae was isolated from two cat bites. Patients were most often treated with a combination of a beta-lactam antibiotic and a beta-lactamase inhibitor, which, on the basis of the microbiologic findings, was appropriate therapy.

CONCLUSIONS

Infected dog and cat bites have a complex microbiologic mix that usually includes pasteurella species but may also include many other organisms not routinely identified by clinical microbiology laboratories and not previously recognized as bite-wound pathogens.