ABSTRACT The aim of this study was to evaluate the effect of florfenicol treatment at doses of 10 and 20 mg/kg administered IM, in the treatment of canine pyoderma due to Staphylococcus intermedius, using pharmacokinetic/pharmacodynamic modelling (PK/ PD). A Monte Carlo simulation of the pharmacokinetic and pharmacodynamic parameters was performed, followed by a PK/PD modelling to determine the efficacy rates in the treatment of bacterial infection, according to the minimum inhibitory concentration (MIC) of S. intermedius, using the range between 0.25 and 2 µg/ml. The probabilities of obtaining the bacteriological eradication index with the 10 mg/kg dose were 97, 77, 7 and 1%, and with the 20 mg/kg dose it was 95, 87, 61 and 7%, according to bacterial MICs of 0.25, 0.5, 1 and 2 µg/ml, respectively. The probability of obtaining a bacteriological cure after treatment with the 10 mg/kg dose decreased significantly for infections caused by microorganisms with MICs higher than 0.5 µg/ml (p<0.01), while for the 20 mg/kg dose kg was with MIC greater than 1 µg/ml (p<0.01). The results show the need to incorporate bacteriological isolation, the determination of MIC and the optimization of therapeutic doses based on bacterial susceptibility in the therapeutic protocol in order to avoid therapeutic failures and, consequently, the increase in the development of microbial resistance.

RESUMEN El objetivo del presente trabajo fue evaluar el efecto del tratamiento con florfenicol en las dosis de 10 y 20 mg/kg administrados por vía IM, en el tratamiento de la pioderma canina por Staphylococcus intermedius, utilizando el modelamiento farmacocinético/ farmacodinámico (PK/PD). Se hizo una simulación de Monte Carlo de los parámetros farmacocinéticos y farmacodinámicos y luego se realizó el análisis PK/PD para determinar las tasas de eficacia en el tratamiento de la infección bacteriana, según la concentración inhibitoria mínima (CIM) del S.intermedius, utilizando el intervalo entre 0.25 y 2 µg/ml. Las probabilidades de obtener el índice de erradicación bacteriológica con la dosis de 10 mg/kg fue de 97, 77, 7 y 1%, y con la dosis de 20 mg/kg fue de 95, 87, 61 y 7%, según las CIMs bacterianas de 0.25, 0.5, 1 y 2 µg/ml, respectivamente. La probabilidad de obtener la cura bacteriológica después del tratamiento con la dosis de 10 mg/kg disminuyó de forma significativa para infecciones causadas por microrganismos con CIM superior a 0.5 µg/ml (p<0.01), mientras que para la dosis de 20 mg/kg fue con CIM mayor de 1 µg/ml (p<0.01). El resultado evidencia la necesidad de incorporar en el protocolo terapéutico el aislamiento bacteriológico, la determinación de la CIM y la optimización de dosis terapéuticas basadas en la susceptibilidad bacteriana a fin de evitar fallas en terapéuticas y, consecuentemente, el incremento del desarrollo de resistencia microbiana.

Descreve-se um surto de abscesso mandibular em ovelhas da raça Bergamácia no município de Botucatu, estado de São Paulo. Do rebanho de 120 animais, 35 apresentaram aumento de volume mandibular com a presença de nódulos únicos, de consistência pétrea, de diferentes tamanhos, fistulados ou não e sem indicativos de inflamação dos tecidos moles adjacentes. Os animais eram criados em pasto de Panicum maximum cv. Tanzânia com água e sal mineral ad libitum e everminados, via oral, com pistolas dosificadoras. O material para diagnóstico microbiológico e antibiograma foi coletado de cinco animais acometidos, por punção e aspiração dos nódulos. Dos 35 animais acometidos, 19 foram submetidos ao exame radiográfico, um ao exame tomográfico e outro à biópsia óssea da região submandibular. O único ovino que morreu, encontrava-se em estado de caquexia provavelmente devido à localização do aumento de volume que afetou a implantação dos dentes molares daquela região impedindo a apreensão e mastigação adequadas levando a perda da condição corporal e morte. Ao exame necroscópico, observaram-se áreas de necrose caseosa na mandíbula direita de onde isolou-se Pseudomonas aeruginosa. O tratamento utilizado foi baseado na aplicação de iodeto de sódio a 10% por via intramuscular e antibioticoterapia segundo antibiograma com enrofloxacina por via intramuscular, porém com pouca eficácia. Diante do quadro clínico, dos dados de anamnese, da localização das lesões no tecido ósseo mandibular, do resultado do cultivo microbiológico, das alterações radiográficas e tomográficas foi feito o diagnóstico de abscesso mandibular causado por Pseudomonas aeruginosa.

We describe an outbreak of mandibular abscess in Bergamácia sheep from the municipality of Botucatu, São Paulo, Brazil. In a herd of 120 sheep, 35 showed an increase of the mandibular volume with presence of a single nodule of stony consistency and different sizes, often fistulated but with no signs of inflammation in the surrounding soft tissues. The sheep were raised on a Panicum maximum cv. Tanzania pasture, with water and mineral salt ad libitum, and were treated orally against parasites with drenching pistols. Material for microbiological diagnosis and antibiogram was collected from the nodules of five affected sheep, through puncture and aspiration. From 35 affected sheep, 19 were submitted to radiographic examination, one was submitted to computer tomography and another to bone biopsy of the submandibular region. The only sheep that died was in a state of cachexia, probably due to the location of the volume increase which affected the molar hindering apprehension and appropriate chewing. Necropsy revealed areas of caseous necrosis in the jaw, from where Pseudomonas aeruginosa was isolated. The sheep were treated with intramuscular application of 10% sodium iodide and the antobiotgic enrofloxacin, but with little efficacy. Based on the clinical data from medical records, the location of lesions in the jaw bone, the result of microbiological culture, radiographic and computer tomography, the diagnosis of mandibular abscesses due to Pseudomonas aeruginosa infection was made.