Clinical evaluation of antiviral combination treatment in cats with feline herpesvirus-1 infection

Feline herpesvirus-1 (FHV-1) can cause lifelong problems such as rhinotracheitis and ocular disease due to latency and reactivation in affected cats. The particular effects of antiviral drugs have been separately investigated in previous studies for decades and little is known about the combination treatment in active FHV-1 infection. Therefore, we aimed to evaluate the effects of antiviral combination on clinical effectiveness in cats with naturally occurring FHV-1 infection. 28 cats suffering from clinical signs of sneezing, nasal congestion, conjunctivitis, and eye/nose discharge were involved in this study following FHV-1 DNA detection by PCR assay in oculo-oropharyngeal samples. The treatment protocol was as follows: oral famciclovir and L-lysine, ophthalmic acyclovir, and subcutaneous amoxicillin plus clavulanic acid. The symptoms improved each day and total recovery success rate was 80% reduction in clinical scores at the end of the treatment on day 10 (p<0.001). Additionally, PCR was found to be negative for FHV-1 DNA in 82.1% of the samples after the treatment. There were mild decreases in neutrophil and monocyte counts (p>0.05). The arginine to lysine ratio decreased in favour of lysine (p<0.01). As a result, the antiviral combination treatment with famciclovir, L-lysine and ophthalmic acyclovir, and antibacterial drug appears to be clinically effective for the treatment of naturally occurring active FHV-1 infection in cats. In addition, any adverse clinical effect has not been determined associated with the antiviral combination during the study.

Isolation of pathogenic aerobic bacteria from the blood of septicaemic neonatal calves and the susceptibility of isolates to various antibiotics

An automated blood culture system (BACTEC 9240) was used for the isolation of aerobic bacteria from the blood of septicaemic neonatal calves. Blood samples were collected from 90 clinically septicaemic and 20 healthy neonatal calves and inoculated into blood culture bottles. There were 89 significant isolates from 90 positive blood cultures using the BACTEC system. Escherichia coli was the most common pathogen detected accounting for 56 (63 %) out of 89 isolates. The other pathogens were β-haemolytic streptococci (15.7 %), Staphylococcusaureus (10.1 %), Klebsiella sp. (5.6 %) and Corynebacterium sp. (5.6 %). All isolates showed a susceptibility rate of 100 % to enrofloxacin, cefepim, cefoperazone / sulbactam, imipenem and meropenem while some of them were ranged from 75 to 91.7 % susceptible to amoxicillin / clavulanic acid, ampicillin / sulbactam, gentamicin and cephalosporins.

Assessment of drug-induced QT interval prolongation in conscious rabbits

INTRODUCTION

Most preclinical trials are designed to identify potential torsadogenicity test only for surrogates of torsade de pointes, most commonly prolongation of the heart rate corrected QT interval (QTc). This study was conducted to determine which correction method best accounts for the effects of changes in the RR interval on the QT interval of conscious rabbits. This study was also conducted to validate the use of conscious, sling-trained rabbits to assess the QTc interval, and to evaluate the reliability and accuracy of this preparation in predicting drug-induced QTc prolongation in humans.

METHODS

ECGs were recorded via bipolar transthoracic ECG leads in 7 conscious rabbits previously trained to rest quietly in slings. The heart rate was slowed with 2.0 mg/kg zatebradine to assess the effects of heart rate on the QT interval. The same ECG and sling preparation was used to evaluate the effects in of three drugs known to be torsadogenic in humans (cisapride, dofetilide and haloperidol), two drugs known to be non-torsadogenic in humans (propranolol and enalaprilat) and a control article (vehicle). All of the test articles were administered intravenously to 4 rabbits, and both RR and QT intervals were measured and the corrected QT values were calculated by an investigator blinded to the test article, utilizing our own algorithm (QTc=QT/(RR)(0.72)) which permitted the least dependency of QTc on RR interval.

RESULTS

The following regression equations were obtained relating QT to RR: QT=2.4RR(0.72), r(2)=0.79, with RR intervals varying between 210 and 350 ms. QTc lengthened significantly in all conscious rabbits given intravenous cisapride, dofetilide and haloperidol (p<0.05), and QTc did not change with DMSO (vehicle control), propranolol or enalaprilat.

DISCUSSION

Results indicate that a bipolar transthoracic ECG recorded in conscious, sling-trained rabbits may provide an easy and economical methodology useful in predicting QTc lengthening of novel pharmacological entities.