Efficacy and safety of cefovecin for the treatment of urinary tract infections in cats

OBJECTIVES: To determine the efficacy and safety of cefovecin (Convenia); Pfizer Animal Health) in the treatment of urinary tract infections in cats. METHOD: A multi-centre, masked, randomised study was conducted in cats presenting with clinical signs indicative of urinary tract infections. Cephalexin (Rilexine); Virbac) administered orally twice daily at 15 mg/kg bodyweight for 14 days was compared with a single subcutaneous injection of cefovecin in cats. The primary efficacy parameter assessed was bacterial elimination of the pretreatment uropathogen. RESULTS: Four hundred and thirty-four cats were screened for urinary tract infections. One hundred and eighty-five cats were treated with either cefovecin (n=124) or cephalexin (n=61). Ninety-seven cats (22.2 per cent) had confirmed bacteriuria and 82 cats were included in efficacy analysis. Escherichia coli was eliminated in 76.7 per cent (23 of 30) of cefovecin-treated cats compared with 62.5 per cent (10 of 16) of cephalexin-treated cats. Cefovecin demonstrated statistical non-inferiority compared with cephalexin for bacterial elimination. There were no suspected adverse drug reactions attributable to treatment with cefovecin or cephalexin. CLINICAL SIGNIFICANCE: Cefovecin was demonstrated to be an effective and safe treatment for urinary tract infections.     

Clinical efficacy and safety of cefovecin in the treatment of canine pyoderma and wound infections

OBJECTIVES: To determine the efficacy and safety of cefovecin in the treatment of bacterial skin infections in dogs. METHOD: Dogs with superficial or deep pyoderma or wounds/abscesses were enrolled in three separate studies. Dogs (354) were randomised to treatment and received either cefovecin administered by subcutaneous injection at 14 day intervals, as clinically necessary, or amoxicillin/clavulanic acid as oral tablets twice daily for 14 days. Courses of treatment were repeated at 14 day intervals up to a total of four courses. Clinicians responsible for assessing lesions were masked to treatment allocation. Only animals where the presence of a pretreatment bacterial pathogen was confirmed were included in the analysis of efficacy. Cases were evaluated for clinical efficacy at 28 days after initiation of the final course of treatment. Clinical efficacy was assessed by scoring the clinical signs typical of skin infections. RESULTS: Cefovecin demonstrated statistical non-inferiority compared with amoxicillin/clavulanic acid for all three clinical diagnoses; for cefovecin, up to 96.9 per cent efficacy was observed versus 92.5 per cent for amoxicillin/clavulanic acid. CLINICAL SIGNIFICANCE: Cefovecin was shown to be as effective as amoxicillin/clavulanic acid administered orally in the treatment of bacterial skin infections in dogs. Cefovecin offers the additional benefit of eliminating owner non-compliance.     

International disease surveillance. International disease monitoring, October to December 2004

To assess whether the rates of antimicrobial susceptibility in bacteria isolated from the urine of dogs with urinary tract infections are similar to those of bacteria isolated from bitches with pyometra, the antimicrobial resistance of Escherichia coli isolated from the two groups were determined and compared. The samples were collected in Sweden between April 2002 and March 2003, and potential changes over time were assessed by comparing the results with corresponding data from 1991 to 1993. Among 80 isolates of E coli from cases of pyometra, the proportions that were resistant to the antimicrobials used in canine practice were generally low (ampicillin 10 per cent, enrofloxacin 4 per cent, gentamicin 0 per cent, streptomycin 5 per cent, sulfamethoxazole 8 per cent, tetracycline 4 per cent and trimethoprim 2 per cent) and similar to the proportions reported previously. Significantly lower proportions of resistance were recorded among the pyometra isolates than among 92 isolates from urine samples submitted by animal hospitals to ampicillin (P=0.04), streptomycin (P=0.002) and tetracycline (P=0.03), but there were no differences between the pyometra isolates and 113 isolates from urine samples submitted by animal clinics.     

Comparison of three techniques for the diagnosis of urinary tract infections in dogs with urolithiasis

OBJECTIVES: To identify an appropriate sampling technique(s) to accurately detect the bacteria causing urinary tract infections in dogs with urolithiasis. METHODS: Twenty-one dogs with urolithiasis were included in the study. Three types of samples were taken from each dog. Urine was collected by cystocentesis, and a urinary bladder mucosal biopsy and urolith were retrieved during cystotomy. The samples were then cultured on blood agar and MacConkey's agar to identify the bacteria associated with urinary tract infections. RESULTS: Bacterial urinary tract infection was found in 16 cases (76.19 per cent). The most prevalent bacteria found to cause urinary tract infection were Escherichia coli (n=7), followed by coagulase-positive Staphylococcus species (n=4), Klebsiella pneumoniae (n=2), Pseudomonas aeruginosa (n=2) and Proteus mirabilis (n=1). In the case of a positive urine culture, the same bacteria were also cultured from the urinary bladder mucosal biopsy alone or from both the urinary bladder mucosal biopsy and urolith. However, in the case of a negative urine culture, bacteria were found to be present in the urinary bladder mucosal biopsy or urolith cultures in 23.81 per cent of dogs. The uroliths that gave positive culture results were either infection-induced uroliths composed of struvite and calcium carbonate phosphate, ammonium acid urate only or metabolic uroliths composed of calcium oxalate and calcium phosphate, or calcium phosphate only. All the uroliths that gave negative culture results were metabolic uroliths composed of calcium oxalate and/or calcium phosphate, and uric acid and calcium phosphate. CLINICAL SIGNIFICANCE: When the culture from the urine obtained by cystocentesis is negative, cultures of urinary bladder mucosal biopsy and urolith are recommended in dogs with urolithiasis in order to accurately assess the microbiological status of the urinary tract.     

Four-year survey of urinary tract infections in calves in Israel

The prevalence of urinary tract infections in calves aged seven days to three months in three dairy cattle herds ranged from 0.5 to 1.6 per cent, with an average of 1.1 per cent. The mortality rate reached 16.1 per cent. The morbidity rate of the female calves was 1.4 per cent and that of the male calves 0.8 per cent. The bacteria isolated from urine, and from vaginal and preputial swabs were Escherichia coli (35 per cent), Corynebacterium renale (14 per cent), plasma coagulase-negative Staphylococcus species (12 per cent), Pseudomonas aeruginosa (12 per cent), Proteus species (12 per cent) and Arcanobacterium pyogenes (5 per cent). The affected calves had a significantly lower serum concentration of inorganic phosphorus (P < 0.01).     

Efficacy and safety of cefovecin in treating bacterial folliculitis, abscesses, or infected wounds in dogs

OBJECTIVE: To evaluate the efficacy and safety of administration of cefovecin, compared with cefadroxil, for treatment of naturally occurring secondary superficial pyoderma, abscesses, and infected wounds in dogs. DESIGN: Multicenter, randomized, positive-controlled clinical trial. ANIMALS: 235 client-owned dogs. PROCEDURES: Dogs with clinical signs of skin infection confirmed via bacteriologic culture were randomly allocated to receive a single SC injection of cefovecin (8 mg/kg [3.6 mg/lb]) followed by placebo administered PO twice daily for 14 days or cefadroxil (22 mg/kg [10 mg/lb]) administered PO twice daily for 14 days following a placebo injection. Two 14-day treatment courses were permitted. Treatment success was defined as reduction of clinical signs to mild or absent at the final assessment. RESULTS: Clinical efficacy achieved with cefovecin in dogs was equivalent to that observed with cefadroxil. At the final assessment, 14 days following the completion of treatment (on day 28 or 42), 92.4% (109/118) of the cefovecin group and 92.3% (108/117) of the cefadroxil group were treatment successes. There were no serious adverse events or deaths related to treatment. CONCLUSIONS AND CLINICAL RELEVANCE: A single cefovecin injection (8 mg/kg) administered SC, which could be repeated once after 14 days, was safe and effective against naturally occurring skin infections in dogs and as effective as cefadroxil administered PO twice daily for 14 or 28 days.     

Multidrug-resistant E. coli and enterobacter extraintestinal infection in 37 dogs

BACKGROUND: Extraintestinal infections caused by multidrug-resistant (MDR) Escherichia coli and Enterobacter are becoming more common in veterinary medicine. OBJECTIVE: To generate hypotheses for risk factors for dogs acquiring extraintestinal infection caused by MDR E. coli and Enterobacter, describe antimicrobial resistance profiles and analyze treatment and clinical outcomes. ANIMALS: Thirty-seven dogs diagnosed with extraintestinal infection caused by MDR E. coli and Enterobacter spp. between October 1999 and June 2006. METHODS: Retrospective case series assembled from hospital records data, including clinical history before 1st MDR isolation and treatment outcome. Identity and antimicrobial susceptibility profiles were confirmed by standard microbiological techniques for 57 isolates. RESULTS: Most dogs had an underlying disease condition (97%), received prior antimicrobial treatment (87%), were hospitalized for >or =3 days (82%), and had a surgical intervention (57%). The urinary tract was the most common infection site (62%), and urinary catheterization, bladder stasis, or both were common among dogs (24%). Some dogs were treated with high doses of co-amoxyclavulanate (n = 14) and subsequently recovered even though the isolates showed in vitro resistance to this antimicrobial. Other dogs were successfully treated with chloramphenicol (n = 11) and imipenem (n = 2). CONCLUSION AND CLINICAL IMPORTANCE: Predisposing disease condition, any prior antimicrobial use rather than a specific class of antimicrobial, duration of hospitalization, and type of surgical procedure might be risk factors for acquiring MDR extraintestinal infections. Whereas culture and sensitivity results can indicate use of last-resort antimicrobials such as imipenem for MDR infections, some affected dogs can recover after administration of high doses of co-amoxyclavulanate.     

Nonenteric Escherichia coli isolates from dogs: 674 cases (1990-1998)

OBJECTIVE: To determine nonenteric sites associated with Escherichia coli isolates in dogs and the antimicrobial susceptibilities of the isolates. DESIGN: Retrospective study. SAMPLE POPULATION: 17,000 canine specimens. PROCEDURE: Medical records of 17,000 canine specimens submitted for bacteriologic culture were examined and the number of isolations of E coli was determined. For these cases, records were further examined with respect to body system involvement, sex, concurrent infection with other species of bacteria, and antimicrobial susceptibility. RESULTS: 674 E coli isolates (424 from urine, 62 from the skin, 52 from the respiratory tract, 45 from the ear, 43 from the female reproductive tract, 25 from the male reproductive tract, and 23 from other organ systems) were identified. There was a significantly higher proportion of isolates from urine specimens from spayed females than from sexually intact females or males. Escherichia coli was isolated in pure culture from 65.9% of the specimens. Most E coli isolates were susceptible to norfloxacin (90%), enrofloxacin (87.5%), gentamicin (90.7%), and amikacin (85.9%). CONCLUSIONS AND CLINICAL RELEVANCE: Most nonenteric E coli infections in dogs involve the urinary tract. Amikacin, gentamicin, norfloxacin, and enrofloxacin have the highest efficacy against canine E coli isolates. For E coli isolates from dogs, in vitro susceptibility to commonly used antimicrobial agents has remained fairly stable during the past decade.     

Usefulness of cefovecin disk‐diffusion test for predicting mecA gene‐containing strains of Staphylococcus pseudintermedius and clinical efficacy of cefovecin in dogs with superficial pyoderma

Background –  Cefovecin has been widely used to treat skin infections in dogs. The relationship of the cefovecin disk‐diffusion test results to the presence of the mecA gene and the clinical efficacy of cefovecin have not been fully evaluated. Hypothesis/Objectives –  To determine the usefulness of an in vitro cefovecin disk‐diffusion test in predicting the presence of the mecA gene in Staphylococcus pseudintermedius, as well as the in vivo efficacy of cefovecin therapy in dogs with superficial pyoderma. Methods –  Twenty‐six S. pseudintermedius strains isolated from 22 dogs with pyoderma were used. In vitro disk‐diffusion test results of cefovecin were compared with agar‐dilution test results, the presence of the mecA gene, and the improvement in clinical scores of dogs with superficial pyoderma at 14 days post treatment. Results –  There was a significant linear correlation (r = ?0.83) between the diameter of the obvious zone of inhibition by disk diffusion and the minimal inhibitory concentration for cefovecin (P < 0.0001). Receiver operating characteristic analysis revealed that zone diameters between 25 and 27 mm exhibited better sensitivity (92.9%) and specificity (100.0%) for detection of strains carrying the mecA gene. The mean improvement in clinical scores in dogs carrying cefovecin‐resistant strains was significantly lower than in dogs carrying cefovecin‐susceptible strains (P < 0.01). Conclusions and clinical importance –  The cefovecin disk‐diffusion test with a cut‐off value estimated in this study was valuable for predicting mecA gene carriage in S. pseudintermedius, as well as the in vivo efficacy of cefovecin therapy in dogs with superficial pyoderma caused by S. pseudintermedius.     

Pipemidic acid, a new treatment for recurrent urinary tract infection in small animals

A new chemotherapeutic agent, pipemidic acid, was used to treat 14 dogs and 2 cats with recurrent urinary tract infection caused by multiresistent strains of Escherichia coli and Proteus spp. Bacterial culture of the urine after treatment revealed disappearance of the microorganisms in all patients. It is concluded that pipemidic acid is a promising chemotherapeutic agent for urinary tract infections caused by multiresistant E. coli and Proteus spp., with the condition that bacterial culture during the course of treatment is obligatory.     

Evaluation of catheter-associated urinary tract infections and multi-drug-resistant Escherichia coli isolates from the urine of dogs with indwelling urinary catheters

OBJECTIVE: To determine the frequency of urinary tract infections (UTIs) in dogs with indwelling urinary catheters in an intensive care unit (ICU) and the frequency of multi-drug-resistant (MDR) Escherichia coli UTIs in those dogs. DESIGN: Prospective study. ANIMALS: All dogs in the ICU with an indwelling urinary catheter from January 2003 through December 2003. PROCEDURES: Urine samples and rectal swab specimens were collected at admission and every 3 days until discharge from the hospital. Escherichia coli isolates from urine samples and rectal swab specimens and those from dogs that were temporally or spatially associated with dogs with MDR E coli UTIs underwent antimicrobial susceptibility testing. Pulsed-field gel electrophoresis was performed on MDR isolates from urine and rectal swab specimens. RESULTS: Urinary catheters were placed in 137 dogs. Twenty-six UTIs were diagnosed, 15 on the day of admission and 11 after 3 or more days of catheterization. Of 12 dogs with E coli UTIs, 6 were infected at admission and 6 acquired the infection in the ICU. Two MDR E coli UTIs were detected, 1 of which was acquired in the ICU. One MDR E coli urinary isolate had an electrophoresis pattern similar to that of rectal isolates from the same dog. Urinary E coli isolates were most frequently resistant to ampicillin and cephalothin. CONCLUSIONS AND CLINICAL RELEVANCE: The ICU-acquired MDR E coli UTI likely originated from the dog's intestinal flora during hospitalization. Dogs that have been referred from a community practice may have MDR E coli UTIs at the time of admission.     

Gentamicin for treatment of resistant urinary tract infections in dogs.

Gentamicin was administered parenterally for 6 days to 43 dogs with urinary tract infections. The daily dosage of 6.6 mg/kg (3 mg/lb) was divided into equal parts and given IM or SC at 8-hour intervals. Dogs selected for treatment with gentamicin had urinary infections that had not responded to treatment with other antimicrobial agents or had bacterial isolates from urine that were resistant to several antimicrobial agents on in vitro susceptibility tests. Response to treatment, defined as negative urine culture on the last day of therapy or 4 to 14 days after completion of the therapeutic course, included 20 of 22 (91%) infections caused by Escherichia coli, 8 of 9 (89%) infections caused by Kebsiella pneumoniae, 6 of 7 (86%) infections caused by Proteus spp, and 6 of 7 infections caused by Pseudomonas spp. These four species comprised 84% of the bacteria isolated from the dogs in this study.     

Comparison of a chlorhexidine and a benzoyl peroxide shampoo as sole treatment in canine superficial pyoderma

The clinical and antibacterial efficacy of two shampoos used as a sole antibacterial treatment in dogs with superficial pyoderma were investigated and compared. In a randomised, partially blinded study, a 3 per cent chlorhexidine gluconate shampoo (Chlorhex 3; Leo Animal Health) was compared against a 2.5 per cent benzoyl peroxide shampoo (Paxcutol; Virbac) in 22 dogs with superficial pyoderma. Dogs were washed two to three times weekly with a 10-minute contact time over 21 days. Clinical scores and bacterial counts were assessed on days 1, 8 and 22 and compared within and between treatment groups; overall response was assessed at the end of the study. Twenty dogs completed the study; 15 (68.2 per cent) showed an overall clinical improvement and the clinical signs resolved in three chlorhexidine-treated dogs. In the chlorhexidine-treated group, scores for papules/pustules (P<0.001), investigator-assessed pruritus (P=0.003), total bacterial counts (P=0.003) and counts for coagulase-positive staphylococci (P=0.003) were reduced after three weeks. Scores and bacterial counts did not vary significantly in the benzoyl peroxide-treated group.     

Urinary tract infection induced by intermittent urethral catheterization in dogs.

Sterilized and unsterilized catheters were passed into the urinary bladders of 9 clinically normal adult male dogs once daily for 5 consecutive days, and the dogs were examined for up to 30 days to determine whether urinary tract infections developed. Two dogs that were catheterized with clean unsterilized catheters (1 clinically normal dog and 1 dog given immunosuppressant drugs) developed persistent cystitis and pyelonephritis due to infection with Proteus sp. One dog given immunosuppressant drugs developed a mixed bacterial infection (Proteus sp and Escherichia coli) that resolved without treatment between 22 and 30 days later.     

Clavulanate-potentiated amoxycillin: activity in vitro and bioavailability in the dog

Clavulanic acid is an inhibitor of beta-lactamase (penicillinase) and when used with amoxycillin the resulting combination becomes active against most bacteria resistant to amoxycillin through production of beta-lactamase. A total of 551 bacterial isolates from dogs and cats were examined by disc sensitivity testing, which showed that there was amoxycillin resistance particularly among staphylococci (50 per cent), Klebsiella species (97 per cent) and Escherichia coli (28 per cent). A combination of potassium clavulanate and amoxycillin reduced the incidence of resistance to 0.3, 3 and 7 per cent, respectively. Minimum inhibitory concentrations were determined for a number of the isolates and showed marked reductions in the presence of potassium clavulanate. A formulation containing amoxycillin trihydrate and potassium clavulanate (4:1) was dosed to beagles at 12.5 mg/kg. Concentrations of the drugs in blood, tissue fluid and skin showed that both drugs were sufficiently well absorbed and distributed to allow a prediction of efficacy against infections caused by beta-lactamase producing bacteria.     

Efficacy, safety and palatability of a new broad-spectrum anthelmintic formulation in dogs

The efficacy, safety and palatability of a new flavoured chewable anthelmintic tablet were investigated in dogs. The efficacy, based on worm counts, of a single recommended therapeutic dose (RTD) of 5 mg pyrantel + 20 mg oxantel + 5 mg praziquantel/kg bodyweight was assessed in experimental infections (EI) and natural infections (NI) with Trichuris vulpis, Echinococcus granulosus and Toxocara canis. For T vulpis, the efficacy of the treatment was 99.3 per cent in EI (comparing groups of six treated and six control dogs) and 100 per cent in NI (nine treated and nine control dogs). For E granulosus, the efficacy was more than 99.9 per cent in EI (11 treated and 11 control dogs). For T canis, the efficacy was 94.3 per cent in EI (10 treated and 10 control dogs) and 100 per cent in NI (12 treated and 13 control dogs). In a field study, Ancylostoma caninum (11 dogs) and T canis (11 dogs) faecal egg counts were reduced by more than 99 per cent, and in eight dogs with Dipylidium caninum proglotides in the faeces the efficacy was 100 per cent. The tablets were readily consumed by 56 of 64 (87.5 per cent) privately owned dogs. Safety was assessed in groups of six dogs treated either once with twice the RTD, once with six times the RTD, with twice the RTD on three consecutive days, or untreated. There were no significant differences in blood parameters between the groups, and no abnormal clinical findings. Two dogs treated with six times the RTD vomited, but no vomiting was observed when administration was repeated two days later.     

Antibiotic susceptibility of bacterial isolates from corneal ulcers of dogs in Taiwan

OBJECTIVES: To analyse antibiotic susceptibility of bacteria associated with ulcerative keratitis in dogs. METHODS: Bacteria isolated from 190 eyes with ulcerative keratitis were identified, and the antibiotic susceptibility of isolates was studied. RESULTS: In total, 258 species of bacteria were isolated from the 190 eyes. Of the isolates, 78 per cent were Gram-positive and 28 per cent were Gram-negative bacteria. The most commonly isolated Gram-positive bacteria in dogs were Staphylococcus spp (49 per cent), Streptococcus spp (7 per cent) and Corynebacterium spp (7 per cent); while Pseudomonas aeruginosa (7.6 per cent) and Escherichia coli (5.8 per cent) were the commonest Gram-negative pathogens. Resistance to commonly used ophthalmic antibiotics was seen in Staphylococcus, Streptococcus, Corynebacterium, Pseudomonas and Escherichia species isolates. CLINICAL SIGNIFICANCE: Isolates from dogs with corneal ulcers in Taiwan may be resistant to several commonly used ophthalmic preparations. Ciprofloxacin showed good action against most isolates, with the notable exception of Streptococcus species. Chloramphenicol or cephalothin had the best in vitro action against the Streptococcus species isolates.     

Chloramphenicol for oral treatment of canine urinary tract infections.

Chloramphenicol was administered orally for 7 to 14 days to 83 dogs with urinary tract infections. The daily dosage of 99 mg/kg (45 mg/lb) was divided into 3 equal parts and administered at 8-hour intervals. Response to treatment (negative urine culture after treatment) varied from 84% (11 to 13) for infections caused by Staphylococcus aureus to 51% (24 of 47) for those caused by Escherichia coli; 82% (14 of 17) of the infections caused by Streptococcus spp and 63% (7 of 11) of those caused by Proteus mirabilis responded to treatment. These 4 species comprised 88% of the bacteria isolated from the dogs.