45 %
55 %

Published on November 19, 2007

Author: Dixon


DEEP BACTERIAL INFECTIONS OF DOGS AND CATS:  DEEP BACTERIAL INFECTIONS OF DOGS AND CATS VMED 5372 Infectious Diseases Dr. Foil OVERVIEW:  OVERVIEW Actinomycosis Nocardiosis Mycobacterial Diseases Tuberculosis Leprosy Atypical Mycobacterial Infection What Do I Need to Know?:  What Do I Need to Know? Really basic microbiology How Acquired? Common Presenting Signs Basic Diagnostic Parameters Basic Treatment Parameters DDX for Mycetoma Actinomycosis:  Actinomycosis Actinomyces spp -- branching, filamentous anaerobic or microaerophilic inhabitants (commensals) of oral cavities of animals and man Actinomycosis:  Actinomycosis Infections are associated with puncture wounds inc. bite wounds Many cases are associated with migrating plant foreign bodies Actinomycosis:  Actinomycosis Adult large breed (sporting breed) dogs are most commonly affected Clinical Features :  Clinical Features Localized pyogranulomas, abscesses or body cavity effusion are seen Most abscesses or draining tracts are found on the head or neck SULFUR GRAINS:  SULFUR GRAINS Exudate is like tomato soup with sulfur grains! Sulfur grains are soft mucoid clumps of organisms CAUSES OF MYCETOMA:  CAUSES OF MYCETOMA Actinomycotic Mycetoma Botryomycosis Eumycotic Mycetoma Pseudomycetoma Actinomyces, Nocardia or other actinomycete Other bacterial infections e.g. Staph Saprophytic fungi Microsporum canis in Persian cats PYOTHORAX:  PYOTHORAX Often associated with plant foreign body Clinical signs = exercise intolerance, weight loss, fever, tachypnea, dyspnea Occasionally, tracts will form through the chest wall Osteomyelitis:  Osteomyelitis Often vertebrae or long bones Often associated with bite wounds Skin Infections:  Skin Infections Cytologic Diagnosis:  Cytologic Diagnosis Careful examination of exudate for sulfur granules These can be crushed and smeared on glass slides Gm positive filamentous branching rods ALL ACTINOMYCETES have similar morphology ANAEROBIC CULTURE:  ANAEROBIC CULTURE A large quantity of exudate WITH sulfur grains is needed to the microbiology lab, fast, in capped syringe Anaerobic transport media even better A large sample of affected tissue may be an alternative 3 PRINCIPLES OF THERAPY:  3 PRINCIPLES OF THERAPY L Lavage and drainage of affected areas. L Debridement of granulation tissue and granulomatous masses. L Long-term antibiotic therapy (weeks to months) ANTIBIOTICS FOR ACTINO:  ANTIBIOTICS FOR ACTINO Penicillin is the drug of choice Pen G 100,000 units/kg q 12-24 h IM, SQ Pen V 50 mg/kg q 8 h PO). Alternatives: erythromycin, minocycline, clindamycin, or chloramphenicol Sensitivity testing is recommended Nocardiosis:  Nocardiosis Nocardia spp are aerobic saprophytic organisms found in rich soil N. asteroides complex N. nova is most commonly associated with disease in dogs and cats N. brasiliensis and N. caviae are sometimes isolated Nocardia infections are much less common (1:9) than Actinomyces in dogs Nocardiosis:  Nocardiosis Infection associated with wound contamination with soil or by inhalation. Inhalation infection or dissemination from a localized infection occurs in immunocompromised hosts Nocardia --3 major forms:  Nocardia --3 major forms Localized: Non-healing wounds with local extension possible, regional lymph node abscessation. Sulfur granules may or may not be present Pyothorax: Signs similar to Actinomycosis but more acutely ill. Sulfur granules may or may not be present. Disseminated form: resembles canine distemper Cytologic Diagnosis:  Cytologic Diagnosis Beaded, filamentous Gram-positive rods Acid-fast stain MAY be positive AEROBIC CULTURE:  AEROBIC CULTURE May require up to 2 weeks SLOW Acid-fast stains on colonies in culture may be more successful than those on tissue or exudate THERAPY:  THERAPY Except in disseminated disease, the 3 therapeutic principles given for Actinomycosis apply First choice antibiotics: Triple sulfa, sulfadiazine or sulfamethoxazole Amikacin, enrofloxacin or minocycline are other choices Streptomyces – another Actinomycete:  Streptomyces – another Actinomycete MYCOBACTERIA:  MYCOBACTERIA Mycobacteria are aerobic, non-spore forming, non-motile, gram-positive, acid-fast, large, slender, beaded rods MYCOBACTERIA:  MYCOBACTERIA Tuberculous Group Leprosy Group Saprophytic (Atypical) Groups I-IV M. tuberculosis M. bovis M. avium M. leprae M. lepraemurium M. avium-intercellulare M. fortuitum group M. chelonae group M. smegmatis group Tuberculosis in Dogs and Cats:  Tuberculosis in Dogs and Cats Incidence increasing because of AIDS Increasing incidence of multiple-drug resistant TB Exposure to infectious body fluids is means of transmission This is a reverse zoonosis – most important in dogs TB -- Forms of Disease:  TB -- Forms of Disease Bronchopulmonary Gastrointestinal Disseminated In all 3 forms, dogs and cats often develop oropharyngeal lesions BRONCHPULMONARY TB:  BRONCHPULMONARY TB ADL, fever, weight loss, and cough Oropharyngeal -- dysphagia, retching, ptyalism, tonsillar enlargement Chest radiographs -- tracheobronchial lymphadenopathy, interstitial to finely granular to consolidating parenchymal infiltrate, calcified nodular densities or pleural or pericardial effusion GASTROINTESTINAL TB:  GASTROINTESTINAL TB Oropharyngeal Symptoms Weight Loss, Anemia, Vomiting Malabsorption Type of Diarrhea Mesenteric Lymph Node Enlargement and Thickened Bowel Loops Palpable DIAGNOSIS:  DIAGNOSIS Can be very challenging Cytologic Examination –Lg Gm + Rods; Acid-Fast Tissue for Path & Culture Large Amounts of Exudate or BX for Culture TB Take Several Weeks; Require Special Agars Intradermal Skin Testing May Be Useful for Dogs but Not Cats TREAT TB?:  TREAT TB? Treatment of Dogs and Cats Is Usually Not Recommended Only With Permission From Public Health Authorities Agents in Combination As in Humans Isoniazid With Rifampin, Streptomycin or Ethambutol (2 Drugs) Atypical Mycobacterial Infections:  Atypical Mycobacterial Infections Atypical Mycobacterial Pyogranulomatous Panniculitis Pulmonary Disease Disseminated Disease ATYPICALS – WHERE?:  ATYPICALS – WHERE? Saprophytic Mycobacteria are ubiquitous in moist sites in the environment. They have been isolated from soil, water, drain pipes, and even bandage materials in hospitals. They are common laboratory contaminants DDX PANNICULITIS:  DDX PANNICULITIS Infectious causes: nocardiosis, actinomycosis, pythiosis, sporotrichosis, botryomycosis, eumycotic mycetoma, blastomycosis, cryptococcosis, tuberculosis, chronic abscessation secondary to FeLV or FIV infection, Rhodococcus equi abscess, bacterial L-forms Non-infectious causes: lymphoreticular or mammary neoplasia, foreign body, nutritional pansteatitis and sterile nodular panniculitis How Is It Acquired?:  How Is It Acquired? MB enter through contaminated wounds Entry in SQ fat is especially important Patients are not immunosuppressed What Does It Look Like?:  What Does It Look Like? Nodular to ulcerative, fibrosing Greasy hemorrhagic purulent exudate Opening of new drainage sites *Surgical excision is typically followed by rapid recrudescence at the surgery site* DIAGNOSIS:  DIAGNOSIS Culture of biopsy-obtained tissues is most reliable The Type IV organisms grow rapidly on either standard or enriched agars Specific ID should always be requested; +/- C & S testing DIAGNOSIS:  DIAGNOSIS Can be Dx’d presumptively on Histopath Takes experience and a Vet Pathologist Special processing for Acid-Fast Stains TREATMENT:  TREATMENT Long-term therapy Relapse on or after tx a problem Surgical debridement Drugs most often effective for fortuitum group -- amikacin, cefoxitin, sulfonamides, fluoroquinolones; +/- clarithromycin and doxycycline, clofazimine. Antituberculosis drugs are not effective

Add a comment

Related presentations

Related pages

Bacterial Infection (Pyoderma) of the Skin in Dogs | petMD

Pyoderma refers to a bacterial infection of the skin that is ... Bacterial Infection (Pyoderma) of the Skin ... article can affect both dogs and cats.
Read more

Bacterial Infection (Pyoderma) of the Skin in Cats | petMD

Pyoderma refers to a bacterial infection of the skin that is generally ... Dogs and cats are expert at hiding ... or if there is a deep ...
Read more

Bacterial Infections in Cats - Veterinary Medical ...

It is also important to keep in mind that most Staph infections in dogs and cats are ... There are a several other odd bacterial infections that do not ...
Read more

Bacterial Skin Infection DOGS - ANIMAL HOSPITAL OF ...

This is a serious bacterial infection with ... rupture of infected hair follicles caused by deep fungal infections, ... At Animal Hospital of Montgomery, ...
Read more

Overview of Pyoderma: Pyoderma: Merck Veterinary Manual

... pyoderma refers to bacterial infections of ... sign of bacterial pyoderma in both dogs and cats is ... of deep pyoderma in dogs are ...
Read more

How to Treat Your Dog's Bacterial Skin Infection - PetMeds ...

Home Pet Education How to Treat Your Dog's Bacterial Skin Infection. ... Bacterial skin infections in dogs often result from an underlying immune disorder.
Read more

Deep Fungal Infections in Cats |

Home Cat Health Infectious Diseases Deep Fungal Infections. ... while the deep infection ... Much more commonly seen in dogs than cats, this infection ...
Read more


DIAGNOSIS AND TREATMENT OF SUPERFICAL AND DEEP BACTERIAL ... in dogs and cats, ... used for superficial infections of the skin. Many dogs with deep ...
Read more