A third case-control study examined the potential dietary risk factors for 92 Scottish terriers > 6 years of age with TCC (cases) and a comparable group of 83 Scottish terriers with no recent history of urinary tract disease (controls). Dog owners completed a questionnaire regarding their dogs' diet and intake of vitamin supplements in the previous year. Dry commercial dog food was the predominant food type consumed daily by > 95% of the case and control dogs, and the length of time dogs were maintained on the reported diet was 7.9 ± 3.1 yr.

After adjustment for age, weight, neuter status, and coat color, consumption of vegetables at least 3 times/wk was associated with a 70% overall reduction in risk of developing TCC (odds ratio, 0.30). The most frequently consumed vegetables were in the yellow-orange group, with carrots fed most often. For individual vegetable types, the risk of developing TCC was reduced 90% with consumption of any green leafy vegetables (odds ratio, 0.12) and 70% with any yellow-orange vegetables (odds ratio, 0.31). These findings are believed to relate to the presence of carotenoids and retinol in green and yellow vegetables, which apparently convey a protective effect against developing bladder cancer in humans and in chemically-induced neoplasms of the bladder in rodents.

Consumption of cruciferous vegetables also reduced the risk of developing TCC, but not significantly (odds ratio, 0.22), possibly because of inadequate sample size as the study population of 175 yielded only a 60% power to detect an 80% decreased risk of TCC. Similarly, the power of the study to detect a 50% reduction in TCC risk associated with daily vitamin supplementation (vitamins E and C) was also low (25%) because of inadequate sample size. Conclusion: Results suggest that consumption of certain vegetables may prevent or slow the development of TCC in Scottish terriers.

Tests Available for Detecting TCC:
BTA (Bladder Tumor Antigen)—Test Code 4383. Sample requirement, 2 mL fresh urine; test s ensitivity 90%, test specificity 78%.
Urine Cytology, preferred urinalysis method with evaluation of cytospin preparation.

References: Glickman et al, JAVMA 224:1290-1297, 2004; Raghavan et al, JAVMA 225:389-394,2004 and JAVMA 227:94-100, 2005.

People: Use topical ointment (Bactroban¨, mupiricin), nasally, q 12 h for 5 d.

Pets: Infections with MRSA in dogs have been reported but their potential role as a reservoir for human infection is controversial. All MRSA reported to date in pets bare the genomic signature of human isolates, indicating a human-to-pet migration. Staph. aureus is not normally a long-term colonizing organism in pets. If found in a nasal or skin swab of an asymptomatic pet, the organism is more likely a transient pathogen from a human host rather than a true colonizing organism. Identification and or treatment of all humans in the household is of primary concern. The role of pets as chronic carriers of human pathogens is not well understood, although prudence is wise. Pets should not be allowed direct contact with any individual who is immunocompromized until the pets have been cultured negative for MRSA. No procedure has been demonstrated to be effective in decontaminating pets. Eradication of the MRSA carrier state from people in the household usually will be effective in removing the organism from the pet.

Of more concern in veterinary medicine is the potential for host adapted Staphylococcal species to acquire the resistance patterns seen in MRSA. Staph. intermedius is the coagulase-positive commensal Staph. spp. of dogs and cats.

The vast majority of Staph. intermedius isolates in dogs and cats do not show methicillin resistance.

Literature reports on Staph. intermedius isolates from dogs and cats and methicillin resistance have given conflicting results: Data from University of Tennessee with 57 Staph. intermedius isolates, only 2 were methicillin resistant, although 50% had the mecA gene detected by PCR testing, suggesting that it may not have been expressed. From the University of Illinois, of 25 methicillin-resistant Staph. intermedius isolates, 23 had mecA gene, and the non-methicillin-resistant isolates did not have the mecA gene. Further work is needed to determine the value of mecA gene detection on veterinary isolates.

Coagulase negative Staphylococcus spp. isolates (such as Staph. schleiferi) in dogs and cats appear to be more commonly detected with methicillin-resistance than do the coagulase positive isolates. These are usually reported from canine pyodermas.

Lack of clinical response to use of any b-lactam antibiotic (e.g. penicillins or cephalosporins)—even if in vitro testing indicates that they are sensitive—indicates that these antibiotics should not be used to treat an MRS infection.

Other choices:

• TMS
  Better than average success against MRS, but not a drug commonly recommended in veterinary medicine, because of potential for adverse reactions.
  
• Quinolones
  
• Vancomycin
  Several disadvantages: very nephrotoxic in dogs; needs to be administered q 6 h by IV route.
  
• Zyvox (Linezolid)
  Member of new family of antibiotics (oxazalinozodes); can be administered enterally or parenterally. Pharmacokinetic evaluation in dogs indicates the effective dose is 20-30 mg/kg q 12 h. Low toxicity, but very expensive. Use only if no other choice; for example, in multi-drug resistant MRS. Zyvox is also effective against vancomycin-resistant enterococcus.

Contributed by Dr. David Aucoin, Zoasis Corp., Diplomate ACVCP