Scientific Investigation and Veterinary information N.14

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The use of Antiseptics in Veterinary DermatologyLuca Guardabassi

Assistant Professor of Clinical Microbiology, University of Copenhagen (Denmark)

Giovanni Ghibaudo DVM, Clinica Veterinaria Malpensa di Samarate, Varese (Italy)

icf informa n°1Malassezia Dr.ssa Fabia Scarampella - Dr.ssa Chiara Noli

icf informa n°2OtocariasiDr. Fabrizio Fabbrini

icf informa n°3PiodermitiDr.ssa Silvia Schiavi - Dr.ssa Antonella Vercelli

icf informa n°4Malattia paradontaleDr.ssa Dea Bonello

icf informa n°5Malattie del canale auricolare esternoDr.ssa Luisa Cornegliani - Dr Giovanni Ghibaudo

icf informa n°6La pulizia dell’orecchioDr.ssa Chiara Tiegh

icf informa n°7SeborreaDr Francesco Albanese

icf informa n°8Dermatite atopicaDr.ssa Franca Galeotti

icf informa n°9OtitiDr Massimo Beccati

icf informa n°10Tris-EDTADr Giovanni Ghibaudo

icf informa n°11Piodermiti e Piodermiti ricorrentiDr. Fabrizio Fabbrini

icf informa n°12Utilizzo prodotti icf in corso di Piodermite e Dermatiteda Malassezia nel caneLaboratorio icf

icf bulletin n°14Utilizzo dei prodotti antisettici in dermatologia veterinariaDr L. Guardabassi - Dr G. Ghibaudo

List of publications

Bulldog male 2 y.o. Skin fold intetrigo

www.icfpet.comScientific Investigation and Veterinary information

The use of Antiseptics in Veterinary DermatologyLuca Guardabassi

Assistant Professor of Clinical Microbiology, University of Copenhagen (Denmark)Giovanni Ghibaudo

DVM, Clinica Veterinaria Malpensa di Samarate, Varese (Italy)

The recent development of multi-resistant bacteria in veterinary medicine, especially methicillin-resistant staphylococci, highlights a need for alternative therapeutic approaches able to eliminate bacte-rial strains that are virtually resistant to all oral antibiotics, while minimising further selection of antibiotic-resistant strains. Among the various recommendations made by experts in the veterinary field (1), topical use of antimicrobial products, including antiseptics, seems the simple and effective treatment for surface skin multi-resistant bacterial infections. Besides clinical efficacy, local antimicrobial treat-ment limits the spread of these bacteria, thus reducing the need for last-resort broad-spectrum systemic antibiotics, which are the main cause behind the spread of antibiotic-resistant bacteria. In veterinary dermatology, situations in which topical antiseptic treatment is a valid alternative to systemic antibiotic therapy are frequent (2, 3). These situations include otitis externa and some forms of surface pyoderma (which only present bacterial overgrowth) such as intertrigo or pyotraumatic dermatitis, and localised surface pyoderma such as mucocutaneous pyoderma

The use of antiseptics that possess antibacterial proper-ties presents many advantages compared to systemic antibiotic therapy. These advantages can be summarised in the five points listed below.

1) Clinical efficacy towards multi-resistant bacterial strains. Antiseptics target microorganisms by mechanisms of action that differ from those of antibiotics. Studies in human medicine have found that antiseptic products have the same efficacy against bacteria that are resistant and sensitive to antibiotics. For instance, various studies on methicillin-resistant Staphylococcus aureus (MRSA) have proved that methicillin-resistance does not influence susceptibility to chlorhexidine (4), which is currently used successfully to decolonise MRSA in humans (5).

Local antimicrobial treatment is an alternative or complimentary approach to antibiotic treatment of methicillin-resistant S. intermedius infections that

have recently emerged in small animals. (6)

Foto G.Ghibaudo

2) Broad spectrum antimicrobial action. While antibiotics, even the broad-spectrum ones, possess a limited spectrum of activity (i.e. cephalospo-rins are not active against Pseudomonas aeruginosa and Malassezia), some antiseptics such as chlorhexedi-ne and phytosphyngosine are microbicidal against almost all the main pathogens in veterinary dermatolo-gy, including staphylococci, streptococci, gram-negative rods (with the sole exception of certain P. aeruginosa strains) and yeasts. The choice of antisepti-cs is therefore particularly advantageous in the treat-ment of mixed infections that involve various bacterial species and microorganisms. This phenomenon is rather common in otitis externa in dogs and infected wounds.3) Complimentary non-antimicrobial properties. Most antiseptics possess secondary beneficial proper-ties in addition to their antimicrobial action. Chlorhexidine’s emollient property is useful for dry and dehydrated skin. Benzoyl peroxide is a keratolytic, antipruritic and degreasing agent.Phytosphyngosine is a natural component of the corne-al layer; it guarantees epidermal barrier function with keratomodulating effects and by controlling sebum production, besides performing a local antiinflammato-ry action. Tris-EDTA has a synergic action with various antibiotics, and it is highly recommended for infections caused by gram-negative rods. The synergic effect seems to issue from a series of mechanisms related to the increase in pH and kelation of divalent cations.

Moreover, Tris-EDTA increases sensitivity in P. aeruginosaI strains resistant to fluoroquinolones, most likely by inhibiting their resistance mechanism. Hence, cases of otitis externa associated with resistant strains can be successfully treated by com-bining Tris-EDTA and chlorhexidine for topical administration. This combination is synergic and, therefore, allows the use of low doses of chlorhexidi-ne (0.15%) that are not ototoxic. (7, 8, 9)4) Low impact on the spreading of resistance. According to the current scientific knowledge, antiseptics do not seem to directly enhance selection of antibiotic resistance and, above all, bacteria do not seem to acquire resistance to the antiseptic concen-trations used for topical treatment. Though bacterial strains that have acquired resistance to antiseptics and disinfectants have been detected, this phenome-non does not seem to be of clinical importance since the antiseptic concentrations used in clinical practice are notably higher than those required to eliminate “resistant” strains. (4, 10, 11)

Foto G.Ghibaudo

Foto G.Ghibaudo

Pyoderma in a cat 7 y.o. male with atopic dermatitis

5) Action circumscribed to the site of the infection. Antiseptics are not absorbed in the blood stream and solely act on the site of infection. Hence, most antisep-tics have no secondary effects on animal health. Inste-ad, antibiotics are a frequent cause of side-effects such as vomiting, diarrhoea, allergies, etc. Moreover, unlike oral antibiotics, antiseptics do not influence the com-position of intestinal microflora, for instance by selec-ting pathogenic bacteria such as Clostridium difficile or by encouraging the development of antibiotic-resistance in opportunist pathogens like Escherichia coli and Enterococcus faecium.All antiseptic products must be used following the indications and the concentrations indicated in the product leaflet.

Foto G.Ghibaudo

Coltura AS Staphylococcus pseudoitermedius

Foto G.Ghibaudo

Coltura batterica su Agar-sangue

The product’s clinical efficacy is ensured by close compliance with exposure times and by educating owners to strictly follow the application times and frequency recommended in the veterinary prescrip-tion. To avoid product contamination, all dilutions must be prepared with sterile water, and solutions must be stored as specified according to the manufacturer’s instructions. Although Tris-EDTA has a synergic effect when combined with certain antibiotics, it would be wrong to stretch this proper-ty to all antiseptic products.

This article highlights the advantages of using antiseptics in veterinary dermatology but it also aims at promoting their rational and appropriate use.

Using Antiseptics in Veterinary Dermatology

1) Guardabassi L., Houser G. A., Frank L. A. and Papich M. G. et al. 2008. Guidelines for antimi-crobial use in small animals. In “Guide to antimi-crobial use in animals”. Eds. Guardabassi L., Jensen L. B. and Hilde K. pp. 183-206. Blackwell Publishing. 2) Guaguere E. 1996. Topical treatment of canine and feline pyoderma. Veterinary Dermatology 7: 145-151.3) Lloyd D. H. 2006. Update on Therapy of Canine Pyoderma. World Small Animal Veterinary Association World Congress Proceedings. (http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2006&PID=15762&O=Generic)4) Weber D. J. And Rutala W. A. Use of germici-des in the home and the healthcare setting: is there a relationship between germicide use and antibio-tic resistance? Infection Control and Hospital Epidemiology 10: 1107-1119.5) Simor A. E., Phillips E., McGeer A., Konvalin-ka A., Loeb M., Devlin R. H. and Kiss A. 2006. Randomized controlled trial of chlorhexidine gluconate for washing, intranasal mupirocin, and rifampin and doxycycline versus no treatment for the eradication of methicillin-resistant Staphylo-coccus aureus colonization. Clinical Infectious Diseases 44:178–185.

Luca GuardabassiAssistant Professor of Clinical Microbiology, University of Copenhagen (Denmark)

Giovanni Ghibaudo DVM, Clinica Veterinaria Malpensa di Samarate, Varese (Italy)

6) Loeffler A., Linek M., Moodley A., Guardabassi L., Sung J. M. L., Winkler M., Weiss R. And Lloyd D. H. 2007. First report of multiresistant, mecA-positive Staphylococcus intermedius in Europe: 12 cases from a veterinary dermatology referral clinic in Germany.Veterinary Dermatology 18: 412-421.7) Ghibaudo G., Cornegliani L., Martino P. Effica-cia e tolleranza di una soluzione con tris-EDTA e clorexidina digluconato 0,15% (Otodine®) nella terapia dell’otite cronica batterica esterna canina. 2007 Summa n.4, pp.23-30. 8) Merchant SR, Neer TM, Tedford BL, et al. Ototoxicity assessment of a chlorhexidine otic preparation in dogs. Prog Vet Neurol 1993;9) Mills P.C. et coll.: Ototoxicity and tolerance assessment of a TrisEDTA and polyhexamethylene biguanide ear flush formulation in dogs, J. vet. Pharmacol. Therap. 28, 391–397, 2005.10) Russell A. 2003. Biocide use and antibiotic resistance: the relevance of laboratory findings to clinical and environmental situations. The Lancet Infectious Diseases 3: 794 – 803.11) Vali L., Davies S. E., Lai L. L. G., Dave J. and Amyes S. G. B.. 2008. Frequency of biocide resistance genes, antibiotic resistance and the effect of chlorhexidine exposure on clinical methicillin-resistant Staphylococcus aureus isolates. Journal of Antimicrobial Chemotherapy 61: 524-532.

References

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