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R. S. Mueller

Bacterial dermatoses

Bacterial dermatoses, also called pyodermas, are rare in the cat despite being so common in the dog ^w. The main reasons for this are perhaps the smali number of bacteria on the skin and coat of the cat and also the importance of grooming in cats^5fi. Bacterial skin infections are most often secondary to trauma, bites or scratches and resolve easily with suitable antimicrobial treatment. On the other hand, some specific bacterial infections, possibly secondary to a systemie illness (e.g. retrovirus infection), can be difficult both to diagnose and to treat.

Abscesses

Aetiopathogenesis

Abscesses are soft tissue infections, caused by the introduction of bacteria into subcutaneous connective tissue, with a bite or scratch. The bacteria responsible belong to resident orał flora. They may be facultative or obligatory anaerobes, including gram negative bacilli such as Pasteurella multocida, Fusobacteńum spp., spirochaetes and gram-positive cocci, in particular B-haemolytic streptococci^A. Entire males are predisposed because of their aggressive naturę.

Clinical features

Dermatological signs are characterised by mostly well-circumscribed and fluctuant, painful swellings which subseąuently burst. Bite marks are sometimes visible. Abscesses do not localise in any one particular place although the face, neck and limbs (Fig. 6 : 1) are most affected in dominant cats and the taił is a typical site in submissive cats.

Systemie signs such as fever, anorexia, lethargy, and regional lymphadenopathy are almost invariable. Diagnosis

Diagnosis is easy and based on the history and clinical signs. Cytological examination of pus, bacterial culture and antibiotic sensitivity, and screening for retroviruses are necessary in recurrent cases.

Treatment

Lancing, surgical drainage and flushing with antiseptic Solutions such as chlorhexidine (0.5%), dilute povidone-iodine or 3% hydrogen peroxide, is necessary in the majority of cases.

Systemie antimicrobial treatment involves the use of broad spectrum antibiotics for about 10 days. As Pasteurella multocida is freąuently isolated, penicillins are the antibiotic of choice. When anaerobic bacteria are present, clindamycin is a good choice of antibiotic (Table 6:1).

Castration and modification of lifestyle, by keeping the cat indoors, may reduce the likelihood of recurrence \