Desember / December 2025 The Monthly Magazine of the SOUTH AFRICAN VETERINARY ASSOCIATION Die Maandblad van die SUID-AFRIKAANSE VETERINÊRE VERENIGING Three Thieves in the Night: subclinical diseases of dairy herds CPD THEME Small Animal Practice nuus•news Access to CPD Articles: https://www.sava.co.za/vetnews-2025/ VET
Dagboek • Diary February 2026 March 2026 June 2026 September 2026 SAEVA Congress 2026 19 - 22 February Venue: Champagne Sports Resort, Drakensberg, KwaZulu Natal Info: https://vetlink.co.za/saeva-congress-2026/ Wildlife Group of the SAVA Congress 2026 12 - 14 March Venue: 26° South Hotel , Muldersdrift, Gauteng Info: https://vetlink.co.za/wildlife-group-2026/ NVCG: The Veterinary Masterclass: Neurology 17 - 18 March Venue: Cape Town Chrystal Towers, Century City 19 - 20 March Venue: Johannesburg, Midrand Premier Hotel Vetlink: https://vetlink.co.za/nvcg-roadshow-march/ or +27 12 346 1590 13th Int Crustacean Society Mid-Year Meeting 01-04 June Venue: STIAS – Stellenbosch Info: https://tcs2026.com/ RuVASA Congress 2026 08 - 10 June Venue: Champagne Sports Resort, Drakensberg, KZN Info: https://vetlink.co.za/ruvasa-congress-2026/ NVCG: The Vet Masterclass: Medicine & Dermatology 19 - 20 September Venue:Johannesburg, Midrand Premier Hotel 21 - 22 September Venue: Cape Town Chrystal Towers, Century City Vetlink: https://vetlink.co.za/nvcg-roadshow-dermmed/ or +27 12 346 1590 13th Biennial SAVA & Para-Veterinary Congress September (date to be confirmed) Venue: to be confirmed (Gauteng) Info: corne@savetcon.co.za This congress is not yet listed on the website as too little information is available at the moment. Watch this space for more information. SAAVT Biennial Congress 30 September - 01 October Venue: Krystal Beach Hotel – Gordon’s Bay Info: conference@savetcon.co.za Ongoing / Online 2025 SAVETCON: Webinars Info: Corné Engelbrecht, SAVETCON, 071 587 2950, corne@savetcon.co.za / https://app.livestorm.co/svtsos Acupuncture – Certified Mixed Species Course Info: Chi University: https://chiu.edu/courses/cva#aboutsouthafrica@tcvm.com SAVA Johannesburg Branch CPD Events Monthly - please visit the website for more info. Venue: Johannesburg Country Club Info: Vetlink - https://savaevents.co.za/ Introduction to Animal Welfare Science 2 CPD POINTS • 1 HOUR • SELF-PACED ONLINE MODULE With a extended conversation between Dr Bert Mohr (Veterinary Specialist, PhD) and Dr Bevin Meyer (Veterinarian, MSc) SAVC ACCREDITED CPD A look at how animals’ ability to feel shapes our responsibility to promote their wellbeing — and explores evolving societal perceptions of animal welfare and consciousness. VC_Ad_90x120.indd 1 2025/11/28 12:11
Vetnuus | December 2025 1 Contents I Inhoud President: Dr Ziyanda Qwalela president@sava.co.za Interim General Manager: Ms Sonja Ludik sonja@sava.co.za/ +27 (0)12 346 1150 Editor VetNews: Ms Andriette van der Merwe vetnews@sava.co.za Accounts / Bookkeeping: Ms Shaye Hughes accounts@sava.co.za/+27 (0)12 346 1150 Reception: Ms Hanlie Swart reception@sava.co.za/ +27 (0)12 346 1150 Marketing & Communications: Ms Sonja van Rooyen marketing@sava.co.za/ +27 (0)12 346 1150 Membership Enquiries: Ms Debbie Breeze debbie@sava.co.za/ +27 (0)12 346 1150 Vaccination Booklets: Ms Debbie Breeze debbie@sava.co.za/ +27 (0)12 346 1150 South African Veterinary Foundation: Ms Debbie Breeze savf@sava.co.za/ +27 (0)12 346 1150 Community Veterinary Clinics: Ms Claudia Cloete manager@savacvc.co.za/ +27 (0)63 110 7559 SAVETCON: Ms Corné Engelbrecht corne@savetcon.co.za/ +27 (0)71 587 2950 VetNuus is die amptelike publikasie van die Suid Afrikaanse Veterinêre Vereeniging (SAVV). Alle regte word voorbehou. Geen deel van hierdie publikasie mag aangehaal, gedupliseer, versprei of aan die publiek beskikbaar gestel word in enige vorm sonder die uitdruklike skriftelike toestemming van die SAVV nie.Hierdie publikasie is uitsluitelik bedoel vir veearts en veearts verwante professionele persone soos deur die Suid Afriaanse Veterinêre Raad erken word. Wyl alles moontlik gedoen word om om die akkuraatheid van die inhoud te verseker, aanvaar nie die redaksie, SAVV of enige van die personeel, lede, werknemers of agente enige regsaanspreeklikheid vir enige verlies, skade of bevooroordeeldheid, hetsy direk of indirek, wat mag spruit uit enige stelling, feit, opinie, advertensie of aanbeveling hierin gepubliseer. Enige advertensie of verwysing na n spesifieke produk is toevallig en word nie noodwending onderskryf of aanbeveel deur die SAVV nie. VetNews is the official publication of the South African Veterinary Association (SAVA). All rights are reserved. No part of this publication may be quoted, reproduced, distributed, or made publicly available in any form or by any means without the prior express written consent of SAVA. This publication is intended solely for veterinarians and paraveterinary professionals as recognised by the South African Veterinary Council. While every effort is made to ensure the accuracy of the content, neither the editorial board, SAVA, nor any of its office bearers, members, employees, or agents shall be held liable for any loss, damage, or prejudice, whether direct or consequential, arising from any statement, fact, opinion, advertisement, or recommendation published herein. The inclusion of advertising or reference to specific products or services does not imply endorsement by SAVA. STREET ADDRESS 47 Gemsbok Ave, Monument Park, Pretoria, 0181, South Africa POSTAL ADDRESS P O Box 25033, Monument Park Pretoria, 0105, South Africa TELEPHONE +27 (0)12 346-1150 FAX General: +27 (0) 86 683 1839 Accounts: +27 (0) 86 509 2015 WEB www.sava.co.za CHANGE OF ADDRESS Please notify the SAVA by email: debbie@sava.co.za or letter: SAVA, P O Box 25033, Monument Park, Pretoria, 0105, South Africa CLASSIFIED ADVERTISEMENTS (Text to a maximum of 80 words) Sonja van Rooyen assistant@sava.co.za +27 (0)12 346 1150 DISPLAY ADVERTISEMENTS Sonja van Rooyen assistant@sava.co.za +27 (0)12 346 1150 DESIGN AND LAYOUT Sonja van Rooyen PRINTED BY Business Print: +27 (0)12 843 7638 VET Diary / Dagboek II Dagboek • Diary Regulars / Gereeld 2 From the President 4 Editor’s notes / Redakteurs notas Articles / Artikels 6 Antimicrobial Resistance Profile of Staphylococcus pseudintermedius Isolated from Dogs.... 13 Mobile Apps in Veterinary Medicine 16 Editorial Piece: Dr Cynthia Otto, DVM, PhD 22 Encouraging Mid-Point Results from SAVA Resiliency Pilot Signal Hope for South African Veterinarians Association / Vereniging 30 CVC News 34 SAVA Benefits 36 SAVA News 38 In Memoriam Vet's Health / Gesondheid 40 Life Coaching Technical / Tegnies 41 Ophthalmology Column 44 Royal Canin Column Marketplace / Markplein 46 Marketplace Jobs / Poste 47 Jobs / Poste 48 Classifieds / Snuffeladvertensies 16 22 Click on the image to access Vetnews CPD articles « nuus•news 30
Vetnews | Desember 2025 2 « BACK TO CONTENTS I trust that members have had a fruitful year, and as we approach the close of 2025, may we all find renewed purpose and pride in the vital role we play in society. This season in the life of our profession reminds us that veterinary service in South Africa is both a privilege and a profound responsibility. Each month brings new challenges and opportunities, and with them, renewed appreciation for the contribution veterinarians make in safeguarding animal health, public health, food security, and the trust our society places in us. Over the past month, several important engagements took place, including the SAVA Annual General Meeting. At the AGM, the SAVA financial statements were formally presented, and more importantly, SAVA received a clean audit opinion. My sincere thanks go to the team from our accounting firm who worked tirelessly to ensure that all required information was provided to the auditors within the agreed timeframes. Receiving a clean audit report affirms our commitment to transparency, accountability, and sound governance — principles that remain central to the confidence our members place in both the SAVA Board and the Association. We also welcomed new members to the SAVA Board: • Dr Melvyn Greenberg, President-Elect • Dr David Pretorius, Finance Director • Dr Jana Prinsloo, Elected Member • Dr Didi Claassen, Elected Member • Dr Erik Verreyne, Elected Member I extend my warmest congratulations to each of them and look forward to the leadership, insight, and energy they will bring. At the same time, we express deep gratitude to our outgoing members — Dr Jono Savadier, Dr Tom Spencer, Maryke Badenhorst, and Dr Paul van der Merwe. It has truly been a pleasure serving alongside you. Your dedication, wisdom, and commitment have strengthened the Association in immeasurable ways. Notably, certain amendments to the Memorandum of Incorporation (MoI) of the Association were adopted, while others require further engagement. These will be discussed and refined for presentation either at a Special General Meeting or at the next AGM. The relationship between SAVA, its Special Interest Groups, and its branches once again came into strong focus,a reminder of the importance of cohesion, clarity, and collaboration within our organisational structures. I must share, however, that it has come to my attention that some groups and branches have recently used the SAVA letterhead in communications on matters that were neither discussed with nor endorsed by the SAVA leadership. This practice undermines the democratic processes, accountability structures, and the spirit of openness and governanceconscious leadership on which SAVA is built. I wish to gently but firmly remind all structures that the SAVA letterhead represents the official position of the Association, and its use must reflect duly authorised communication channels and decisions. That said, we continue to battle a protracted Foot-and-Mouth Disease (FMD) outbreak, which has placed immense pressure on veterinarians, farmers, and provincial veterinary services alike. The recent press statement issued by the Minister of Agriculture signals a significant policy shift, endorsing mass vaccination of cattle beginning in the affected provinces: North West, KwaZulu-Natal, Free State, Gauteng, and Mpumalanga. As SAVA, we welcome the ongoing evaluation of national disease-management policy and trust that the weeks ahead will bring further engagement and clarity on the pathway South Africa will adopt regarding FMD control. It remains our hope that this direction will align with the WOAH Progressive Control Pathway for FMD, ensuring an evidence-based, sustainable, and internationally credible approach that focuses on enabling industry growth and sustainable enterprises for both the commercial and emerging sector. Rabies also remains a serious scourge in our country, continuing to claim preventable human and animal lives. Let us continue to encourage our clients, communities, and the broader public to adhere to essential control measures — most importantly the vaccination of pets, early reporting of suspicious cases, and rapid response to potential exposures. The recent detection of rabies in Cape Fur seal populations remains a major concern, highlighting the evolving nature of this disease and reinforcing the need for sustained surveillance, intersectoral collaboration, and strong public awareness. This issue of Vetnews places special focus on small animals, spotlighting the critical work being undertaken across companion-animal practice, community outreach, and welfare organisations. Small-animal clinicians play an indispensable role in strengthening the bond between people and their animals, improving public health, and contributing to the broader One Health agenda. Their work is often deeply personal, profoundly impactful, and at the heart of many communities — and we are proud to highlight their contributions in this edition. I would like to extend my sincere appreciation to the SAVA personnel. Your professionalism, resilience, and commitment have carried the Association through an exceptionally busy and demanding year. Despite the challenges of recent years, you have continued to serve our members with dedication and excellence. Thank you for your hard work, patience, and unwavering support to the Board and the broader profession. I would also like to thank the Pig Veterinary Society leadership for their generous donation of an overhead projector for the SAVA Boardroom — a gesture that is sincerely appreciated. As we approach the festive season, I wish all our members, partners, and their families a peaceful and restorative holiday period. May it bring rest, joy, and meaningful time with loved ones. May the close of 2025 be marked with gratitude, and may 2026 greet us with strength, clarity, and shared purpose. v Groetnis! Ziyanda From the President Dear members, What a year!
Vetnuus | December 2025 3 To find out more: You are looking for a be琀琀er way to exit from or sell your practice. You want to become a shareholder. www.companion.partners WhatsApp View Video Download Value Proposition co.mpanion is not a corporate body, it is a professional owned and led veterinary model that is right for you if: Building be琀 琀er practice together. co.llaborative model that gives you the ownership, support and autonomy Image: Dr Werner Odendaal, Shareholder & Team Member,
Vetnews | Desember 2025 4 « BACK TO CONTENTS This months Vetnews’ has a very exciting article on the midterm results of the resiliency program presented by The Lincoln Institute Of Veterinary Business from Australia. Late last year, 65 participants were recruited from SAVA members. In February the program kicked off with weekly assignments and deep-dive sessions every three months. This month the halfway point results were received. The program focusses on the development of veterinary soft skills. It aims to enable the veterinarian to firstly care for him/herself, better the relationship with colleagues and to better the relationship with clients. Have a look at the great feedback from some of the participants and what the statistics are showing. Further, find an interview with Dr (Prof) Cindy Otto. Prof Otto was one of the veterinarians at Ground Zero after the 911 attacks in America. Subsequently she started up a working dog training and treatment centre in Pennsylvania. It is fascination to read the work she has done and the rewards she has achieved. We have a look the AMR profile of S. pseudintermedius isolated in dogs with Otitis Externa and Healthy dogs, as well as he role of mobile apps in Veterinary Medicine. Decembers is a time of celebration for most. But there will always be the veterinarian, the nurse, the technician, the kennel hand, the receptionist and related personnel that will keep the ship afloat. We see you, we salute you. We honour your dedication. For the rest of us who will be enjoying some time off, going away or staying home, being alone or entertaining friends or family, please drive safely, enjoy your time off and be mindful of yourself and others. May you enjoy your Christmas time! Andriette v From the Editor Editor’s notes / Redakteurs notas Death leaves a heartache no one can heal, love leaves a memory no one can steal. Maria Elizabeth (Elize) Nicholas 06 Maart 1950 – 30 November 2025 May her soul rest in peace.
Vetnuus | December 2025 5 Hill’s Science Plan Small & Mini Mousses offer a deliciously soft taste and texture with specialised nutrition fit for their size! The right combination of protein, fats and carbohydrates provide the energy they need. 1 Powerful blend of antioxidants to support their immune system. 2 Easy-to-digest ingredients to promote gut health. 3 V35196, V35192 © Hill’s Pet Nutrition, Inc. 2025 small in size, big on benefits
Vetnews | Desember 2025 6 « BACK TO CONTENTS Antimicrobial Resistance Profile of Staphylococcus pseudintermedius Isolated from Dogs with Otitis Externa and Healthy Dogs: Veterinary and Zoonotic Implications Ionela Popa 1, Ionica Iancu 2*, Vlad Iorgoni 2, Janos Degi 2, Alexandru Gligor 2, Kalman Imre 3, Emil Tîrziu 4, Timea Bochis1, Călin Pop1, Ana-Maria Plotuna5, Paula Nistor 2, Marius Pentea 6, Viorel Herman 2 and Ileana Nichita 4 1 Department of Semiology, Faculty of Veterinary Medicine, University of Life Sciences “King Mihai I”, 300645 Timisoara, Romania; ionela.popa@usvt.ro (I.P.); timea. bochis@usvt.ro (T.B.); calinpop@usvt.ro (C.P.) 2 Department of Infectious Diseases and Preventive Medicine, Faculty of Veterinary Medicine, University of Life Sciences “King Mihai I”, 300645 Timisoara, Romania; vlad. iorgoni@usvt.ro (V.I.); janosdegi@usvt.ro (J.D.); alexandru.gligor@usvt.ro (A.G.); paula.nistor@usvt.ro (P.N.); viorel.herman@fmvt.ro (V.H.) 3 Department of Food Safety and Hygiene, Faculty of Veterinary Medicine, University of Life Sciences “King Mihai I”, 300645 Timisoara, Romania; almanimre@usvt.ro 4 Department of Microbiology, Faculty of Veterinary Medicine, University of Life Sciences “King Mihai I”, 300645 Timisoara, Romania; emiltirziu@usvt.ro (E.T.) 5 Department of Animal Nutrition, University of Life Sciences “King Mihai I”, 300645 Timisoara, Romania; anamaria.plotuna@usvt.ro 6 Department of Anatomy, University of Life Sciences “King Mihai I”, 300645 Timisoara, Romania; mariuspentea@usvt.ro * Correspondence: ionica.iancu@usvt.ro Abstract Background/Objectives: Staphylococcus pseudintermedius (S. pseudintermedius) is an opportunistic pathogen frequently isolated from dogs, involved in a wide range of infections, particularly otitis externa. Increasing antimicrobial resistance (AMR), including methicillin-resistant S. pseudintermedius (MRSP), poses significant challenges for veterinary and potentially human health. This study aimed to assess the prevalence and antimicrobial resistance profiles of S. pseudintermedius in dogs with otitis externa compared to clinically healthy dogs. Methods: Between 2022 and 2025, samples were collected from 400 dogs with otitis externa and 360 healthy dogs in veterinary clinics from Timis, oara. Ear swabs were processed by conventional microbiological techniques and confirmed using MALDI-TOF MS. Antimicrobial susceptibility was tested using the VITEK® 2 Compact system, following CLSI VET01, Fifth Edition (2018) standards. Fourteen antimicrobials from 11 classes were evaluated. Results: S. pseudintermedius was isolated in 40% of dogs with otitis externa and in 21.1% of healthy dogs. The highest resistance in both groups was observed to tetracycline (37.5% and 25%, respectively). No resistance was recorded to linezolid, vancomycin, teicoplanin, tigecycline, or fusidic acid. MRSP strains were identified in 1.2% of dogs with otitis, displaying multidrug resistance (MDR). MDR strains were also detected in 8.7% of diseased and 4% of healthy dogs, indicating the potential for subclinical reservoirs. Conclusions: The findings highlight the notable prevalence and AMR of S. pseudintermedius in both symptomatic and asymptomatic dogs. The detection of MRSP and MDR strains emphasises the need for prudent antibiotic use and continuous AMR surveillance in veterinary medicine to mitigate zoonotic risks and preserve antimicrobial efficacy. 1. Introduction S. pseudintermedius, an opportunistic pathogen, is commonly isolated from clinically healthy dogs and is notably involved in a wide spectrum of animal infections [1]. This bacterium can colonise between 46% and 92% of healthy dogs [2]. S. pseudintermedius is recognised as a key pathogen in dogs, has also occasionally been linked to cases of human infection [3,4], while it also plays a significant role in infections among cats [4]. The growing identification of S. pseudintermedius isolated from canine cases of otitis externa and soft tissue or skin infections represents a rising concern in the veterinary field, primarily due to its considerable resistance to antimicrobials and a broad range of virulence factors [5]. Antimicrobial resistance (AMR) has become a major global health issue, widely recognised as one of the most critical threats of this century, with implications for both human and animal health [6–9]. In recent years, there has been an observed increase in the frequency of methicillin-resistant S. pseudintermedius (MRSP) strains, both in sick dogs and in clinically healthy ones [10]. The spread of MRSP has come to represent a major issue in veterinary practice [11]. MRSP resistance is determined by the presence of the mecA gene, integrated into a mobile genetic element known as the staphylococcal chromosomal cassette mec (SCCmec). This gene confers resistance to most beta-lactam antibiotics, except for ceftaroline and ceftobiprole, which are part of the fifth generation of cephalosporins [11,12]. The mecA gene encodes a structurally altered penicillin-binding protein with low affinity for nearly all beta-lactam antibiotics [10,13]. Consequently, these antibiotics no longer represent a barrier to bacterial cell wall synthesis, unlike under normal circumstances when beta-lactams bind to the penicillin-binding protein and thereby inhibit the bacterium’s ability to construct its cell wall [13]. In addition, the SCCmec acquired by MRSP is a mobile genetic element [10–13] that may also carry other resistance genes, contributing, along with other mobile genetic elements, to multidrug resistance patterns (MDR) [12]. Resistance of MRSP strains has also often been observed within other classes of antimicrobials, namely: aminoglycosides, fluoroquinolones, macrolides [11,12], trimethoprim–sulfamethoxazole, lincosamides, tetracyclines, and chloramphenicol [12]. S. pseudintermedius can be transmitted to humans, particularly those in close contact with dogs, potentially causing zoonotic infections such as abscesses, infected bite wounds, pneumonia, bloodstream infections, and septic arthritis [10]. Consequently, MRSP has become an increasingly significant concern in veterinary as well as human medicine, due to the limited treatment options available [14].
Vetnuus | December 2025 7 Leading Article The objectives of this study were to determine the prevalence of S. pseudintermedius in dogs with otitis externa compared to clinically healthy dogs, to characterise the antimicrobial resistance profiles of the isolates against both veterinary and human-use antibiotics, to identify MRSP and MDR strains, and to assess their potential zoonotic implications. These aims were designed to provide a clearer understanding of the epidemiological role of S. pseudintermedius in canine populations and to support strategies for prudent antimicrobial use in veterinary medicine. 2. Results 2.1 Prevalence of S. pseudintermedius Isolated from Dogs with Otitis Externa and from the Ears of Healthy Dogs. Out of 400 samples collected from dogs diagnosed with otitis externa, S. pseudintermedius was isolated in 160 cases, representing a prevalence rate of 40%. From the ears of clinically healthy dogs, the bacterium was identified in 76 out of 360 samples, corresponding to a prevalence of 21.1%. 2.2 Antimicrobial Resistance of S. pseudintermedius Strains Isolated from Dogs with Otitis Externa. Among dogs with otitis externa, S. pseudintermedius showed the highest resistance to tetracycline (37.5%, n = 60). No resistance was observed to linezolid, teicoplanin, vancomycin, fusidic acid, and tigecycline, with 100% susceptibility (n = 160) (Table 1). Antimicrobial Class Antimicrobial Number of Strains Tested Susceptible, n (%) Resistant, n (%) Beta-lactams Penicillin 160 123 (80.3) 37 (19.7) Oxacillin 160 158 (98.7) 2 (1.3) Aminoglycosides Gentamicin 160 158 (98.7) 2 (1.3) Tetracyclines Tetracycline 160 100 (62.5) 60 (37.5) Fluoroquinolones Ciprofloxacin 160 158 (98.7) 2 (1.3) Moxifloxacin 160 158 (98.7) 2 (1.3) Macrolides Erythromycin 160 158 (98.7) 2 (1.3) Lincosamides Clindamycin 160 125 (78.1) 35 (21.9) Oxazolidinones Linezolid 160 160 (100) 0 (0) Glycopeptides Teicoplanin 160 160 (100) 0 (0) Vancomycin 160 160 (100) 0 (0) Fusidans Fusidic acid 160 160 (100) 0 (0) Glycylcyclines Tigecycline 160 160 (100) 0 (0) Sulfonamides + Pyrimidines Trimethoprim + Sulfamethoxazole 160 154 6.2) 6(3.8) Table 1. Antimicrobial resistance of S. pseudintermedius strains isolated from dogs with otitis externa 2.3 Antimicrobial Resistance of S. pseudintermedius Strains Isolated from the Ears of Healthy Dogs. Additionally, S. pseudintermedius isolated from samples collected from the ears of healthy dogs exhibited the highest resistance to tetracycline as well, at a rate of 25% (n = 19) (Table 2). Antimicrobial Class Antimicrobial Number of Strains Tested Susceptible, n (%) Resistant, n (%) Beta-lactams Penicillin 76 61 (80.3) 15 (19.7) Oxacillin 76 76 (100) 0 (0) Aminoglycosides Gentamicin 76 76 (100) 0 (0) Tetracyclines Tetracycline 76 57 (75) 19 (25) Fluoroquinolones Ciprofloxacin 76 76 (100) 0 (0) Moxifloxacin 76 76 (100) 0 (0) Macrolides Erythromycin 76 76 (100) 0 (0) Lincosamides Clindamycin 76 59 (77.6) 17 (22.4) Oxazolidinones Linezolid 76 76 (100) 0 (0) Glycopeptides Teicoplanin 76 76 (100) 0 (0) Vancomycin 76 76 (100) 0 (0) Fusidans Fusidic acid 76 76 (100) 0 (0) Glycylcyclines Tigecycline 76 76 (100) 0 (0) Sulfonamides + Pyrimidines Trimethoprim + Sulfamethoxazole 76 76 (100) 0 (0) Table 2. Antimicrobial resistance of S. pseudintermedius strains isolated from the ears of healthy dogs
Vetnews | Desember 2025 8 « BACK TO CONTENTS Analysis by antimicrobial class revealed that the most frequent resistance in both groups occurred within the tetracycline class. In isolates from dogs with otitis externa, 37.5% were resistant to tetracyclines, 23.1% to β-lactams, and 21.9% to lincosamides. In isolates from the ears of healthy dogs, the corresponding resistance rates were 25%, 19.7%, and 22.4%, respectively. All isolates were fully susceptible to glycopeptides, oxazolidinones, fusidanes, and glycylcyclines (Table 2). 2.4 Distribution of MDR and MRSP Strains. Regarding MDR, 14 strains (8.7%) were isolated from samples collected from dogs with otitis externa (Table 3), while 3 strains (4%) were isolated from samples taken from the ears of healthy dogs (Table 4). Additionally, two MRSP strains (1.2%) were isolated from samples collected from dogs with otitis externa (Table 3). Regarding the MRSP strains, in addition to resistance to β-lactam antibiotics, they also exhibited resistance to antimicrobials from the following classes: aminoglycosides, tetracyclines, fluoroquinolones, macrolides, lincosamides, and sulfonamides + pyrimidines (Table 3). A comparative statistical analysis of S. pseudintermedius prevalence and antimicrobial resistance between isolates from dogs with otitis externa and those from clinically healthy dogs is presented below (Table 5). This analysis includes p-values, false discovery rate (FDR)-adjusted q-values, risk differences (RD), and relative risks (RR) with 95% confidence intervals, providing an inferential assessment of the significance and magnitude of the observed differences. Antimicrobial Resistance Number of Strains and Percentage Susceptible to all tested antimicrobials 61 (38.1%) PEN 14 (8.8%) TET 37 (23.1%) CLI 25 (15.6%) TET + PEN 9 (5.6%) PEN + TET + CLI 8 (5%) PEN + TET + SXT 4 (2.5%) PEN + OXA + GEN + TET + CIP + MXF + ERY + CLI + SXT 2 (1.2%) Table 3: Antimicrobial resistance profiles of S. pseudintermedius strains isolated from dogs with otitis externa (distribution according to the resistance profile of each strain) Antimicrobial Resistance Number of Strains and Percentage Susceptible to all tested antimicrobials 31 (40.8%) CLI 14 (18.4%) TET 16 (21.1%) PEN 12 (15.8%) PEN + TET + CLI 3 (4%) Table 4. Antimicrobial resistance of S. pseudintermedius strains isolated from the ears of healthy dogs (distribution based on resistance profile of each isolate) Antimicrobial/ Parameter Otitis Externa (n/N, %) Healthy Dogs (n/N, %) p-Value q-Value (FDR) Risk Difference (%, 95% CI) Relative Risk (95% CI) Prevalence (S. pseudintermedius) 160/400 (40.0%) 76/360 (21.1%) <0.0001 — 18.9% (12.2%, 25.6%) 1.90 (1.52–2.36) Penicillin resistance 37/160 (23.1%) 15/76 (19.7%) 0.5712 0.6614 3.4% (−8.4%, 15.2%) 1.17 (0.67–2.04) Oxacillin resistance (MRSP) 2/160 (1.3%) 0/76 (0.0%) 0.5303 0.6614 1.3% (−1.3%, 4.0%) 3.39 (0.17–66.7) Gentamicin resistance 2/160 (1.3%) 0/76 (0.0%) 0.5303 0.6614 1.3% (−1.3%, 4.0%) 3.39 (0.17–66.7) Tetracycline resistance 60/160 (37.5%) 19/76 (25.0%) 0.0714 0.1429 12.5% (−1.1%, 26.1%) 1.50 (0.96–2.33) Ciprofloxacin resistance 2/160 (1.3%) 0/76 (0.0%) 0.5303 0.6614 1.3% (−1.3%, 4.0%) 3.39 (0.17–66.7) Moxifloxacin resistance 2/160 (1.3%) 0/76 (0.0%) 0.5303 0.6614 1.3% (−1.3%, 4.0%) 3.39 (0.17–66.7) Erythromycin resistance 2/160 (1.3%) 0/76 (0.0%) 0.5303 0.6614 1.3% (−1.3%, 4.0%) 3.39 (0.17–66.7) Clindamycin resistance 35/160 (21.9%) 17/76 (22.4%) 0.9284 0.9284 −0.5% (−12.8%, 11.8%) 0.98 (0.58–1.64) Trimethoprim– Sulfamethoxazole resistance 6/160 (3.8%) 0/76 (0.0%) 0.1832 0.3664 3.8% (−0.9%, 8.4%) 6.15 (0.35–107.8) MDR (≥3 classes) 14/160 (8.7%) 3/76 (4.0%) 0.2845 0.4735 4.7% (−3.9%, 13.3%) 2.17 (0.64–7.31) MRSP (oxacillin-resistant) 2/160 (1.3%) 0/76 (0.0%) 0.5303 0.6614 1.3% (–1.3%, 4.0%) 1.39 0.17–66.7) Legend: PEN—penicillin; OXA—oxacillin; GEN—gentamicin; TET—tetracycline; CIP—ciprofloxacin; MXF— moxifloxacin; ERY—erythromycin; CLI—clindamycin; SXT—trimethoprim + sulfamethoxazole. Legend: PEN—penicillin; CLI—clindamycin; TET—tetracycline. Table 5. Statistical comparison of antimicrobial resistance rates in S. pseudintermedius isolates from dogs with otitis externa and from clinically healthy dogs Leading Article Antimicrobial Resistance Profile of Staphylococcus pseudintermedius ..... <<< 7
Vetnuus | December 2025 9 Note: p-values < 0.05 were considered statistically significant. False discovery rate (FDR)-adjusted q-values were calculated using the Benjamini–Hochberg procedure and are presented for comparisons involving multiple antimicrobial resistance outcomes. The prevalence comparison was not included in the multiple testing correction as it represents a single test; therefore, only the raw p-value is reported for this parameter. Risk difference (RD) and relative risk (RR) are provided with 95% confidence intervals (CI). RD represents the absolute difference in resistance proportions between the two groups, whereas RR reflects the relative likelihood of resistance in isolates from dogs with otitis externa compared to those from clinically healthy dogs. 3. Discussion The prevalence of S. pseudintermedius in this study was 40%, which is consistent with findings reported by Hassan et al. [15] (41.6%) and Penna et al. [16] (38.4%), and somewhat higher than the 31.5% reported by De Martino et al. [17]. These similarities may reflect broadly comparable epidemiological conditions and sampling strategies across studies, such as targeting clinical isolates from companion animals with similar clinical presentations. However, slight differences in prevalence could stem from geographic variability, including differences in population density, pet ownership practices, and local veterinary diagnostic capacities. Moreover, differences in study design, such as sample size or inclusion criteria, could also influence prevalence rates and partially account for the variability observed across studies. AMR profile revealed a predominance of tetracycline resistance (37.5%) (Table 1), consistent with De Martino et al. [17] (35.5%) and Rosales et al. [18] (41.7%). The slightly lower or higher values observed in these studies likely reflect variations in local antimicrobial usage patterns. For example, tetracyclines remain widely used in veterinary medicine due to their broad-spectrum activity and affordability, which may contribute to a sustained selective pressure favouring resistant strains. The even higher resistance rate reported by Tesin et al. [19] (52%) may be influenced by regional overuse or misuse of tetracyclines, as well as the inclusion of isolates from animals with recurrent infections, where resistance is typically higher. Resistance to penicillin was observed in 23.1% of isolates. This rate is considerably lower than the values reported by Bourély et al. [20] (68.5%), Rosales et al. [18] (69%), and Scherer et al. [21] (77.3%), but higher than the 7% reported by Rubin et al. [22]. Several factors may account for these discrepancies. First, methodological differences, such as the antimicrobial susceptibility testing method employed (e.g., disk diffusion vs. MIC determination), the inclusion or exclusion of intermediate isolates, and the interpretive criteria applied (e.g., CLSI vs. CA-SFM), can significantly influence reported resistance rates [22]. Second, the studies differ in the bacterial populations analysed: while our study focused exclusively on S. pseudintermedius, others may have included mixed staphylococcal species or isolates preselected based on methicillin susceptibility, which could introduce selection bias. Third, regional variation in antimicrobial stewardship strategies, veterinary prescribing behaviours, and regulatory frameworks likely contributes to differences in resistance patterns. Given these substantial methodological and epidemiological differences, direct comparisons across studies should be interpreted with caution. Clindamycin resistance was observed in 21.9% of isolates, aligning with Rosales et al. [18] (29.4%) but higher than the 9% reported by Norström et al. [23]. These differences may reflect variation in the therapeutic use of lincosamides across regions. Moreover, Norström et al. [23] isolated S. pseudintermedius from both otic and skin infections, and it is possible that site-specific differences in bacterial populations or exposure to clindamycin contributed to the lower resistance observed. Gentamicin resistance was low (1.3%) in our study, which matches the 1% reported by Bugden [24] and is notably lower than values from De Martino et al. [17] (11.1%), Bourély et al. [20] (13.5%), and Rosales et al. [18] (17.6%). This finding may suggest that aminoglycosides are either used sparingly or mainly in severe infections where culture and sensitivity testing are performed, limiting their contribution to resistance selection. Similarly, erythromycin resistance was very limited (1.3%), in stark contrast to the much higher rates reported by Rosales et al. [18] (29.7%), Bourély et al. [20] (29.8%), and especially Penna et al. [16] (80%). These discrepancies likely reflect regional differences in antimicrobial policies and prescription behaviours, and possibly different exposure histories of the bacterial populations sampled. Trimethoprim-sulfamethoxazole resistance was found in only 3.8% of isolates, consistent with Rubin et al. [22] (5%), but considerably lower than rates reported by Rosales et al. [18] (18%) and De Martino et al. [17] (46.6%). The low resistance rate observed in our study may indicate either limited use of this antibiotic in clinical veterinary practice or its continued efficacy due to stewardship efforts. It is also possible that local veterinary guidelines prioritise other antimicrobials, thus reducing the selective pressure for resistance to this compound. In the present study, the susceptibility of S. pseudintermedius isolates was assessed with respect to several antimicrobials reserved solely for human use. This included linezolid, vancomycin, tigecycline, and teicoplanin—agents classified as important and reserved for the treatment of human infections. Additionally, moxifloxacin, a fluoroquinolone approved for human use, was tested [25]. All isolates were susceptible to antibiotics reserved for human use (linezolid, vancomycin, tigecycline, and teicoplanin), demonstrating 100% susceptibility (n = 160) (Tables 1 and 2). In contrast, a resistance rate of 1.3% (n = 2) was observed for moxifloxacin (Table 1). The monitoring of AMR should extend beyond agents exclusively used in veterinary medicine, given the zoonotic threat posed by MRSP and its capacity to spread AMR genes via horizontal gene transfer [26]. Regarding MDR strains, they were isolated at a rate of 8.7% in this study (Table 3). Our findings differ from those reported by Viegas et al. [11], who documented an MDR prevalence of 14.5% among S. pseudintermedius strains isolated from canine external otitis cases. The proliferation of MDR bacterial strains constitutes a critical threat to global health, as underscored by the World Health Organisation. The rising incidence of infections attributable to MDR organisms, alongside the dwindling efficacy of current therapeutic options, is projected to contribute to increased fatality levels among animal and human hosts affected by such diseases. MDR is generally defined by resistance to antimicrobial agents spanning a minimum of three distinct antimicrobial classes [27]. Regarding the MRSP strains, they were isolated at a rate of 1.2% in this study (Table 3). Leading Article
Vetnews | Desember 2025 10 « BACK TO CONTENTS Our results differ from those reported by Viegas et al. [11], who found MRSP strains in 17.6% of dogs with external otitis. According to the literature, the prevalence of MRSP among canine populations shows wide variation, with reported values spanning from 0% to 60% [11]. It is important to note that drawing direct comparisons across studies can be challenging, as MRSP prevalence is influenced by multiple factors, including the study population, sample type, geographic location, and methodological approach [11]. According to CLSI guidelines, staphylococci showing resistance to oxacillin are interpreted as resistant to each class of β-lactam antibiotics. In antimicrobial susceptibility testing, methicillin was substituted with oxacillin due to its greater stability [28]. Beyond their resistance to β-lactam antibiotics, MRSP strains commonly possess resistance to several other antimicrobial drug classes [13]. Regarding penicillin resistance among S. pseudintermedius strains isolated from the ears of healthy dogs, the prevalence observed in this study was 19.7% (Table 2). This value is lower than the 39.9% reported by Rubin and Chirino-Trejo [29], who analysed isolates from nasal, pharyngeal, and rectal sites. One possible explanation for this discrepancy is the anatomical site of sampling, as microbial populations and resistance profiles can vary significantly between different body regions due to differences in local microenvironments and antimicrobial exposure. In addition, geographic variation and differences in antimicrobial use practices between populations or regions may also contribute to this divergence. Similarly, the tetracycline resistance rate in our study was 25%, closely aligning with the 23.5% reported by Rubin and ChirinoTrejo [29]. This consistency might suggest a more stable pattern of tetracycline resistance across different body sites and potentially across different geographical regions. However, the similarity could also reflect the widespread and long-term use of tetracyclines in veterinary medicine, which may have exerted consistent selective pressure over time. Regarding MRSP, no strains were identified in our study. This is consistent with the findings of Rubin and Chirino-Trejo [29], who also reported no MRSP in clinically healthy dogs. The absence of MRSP in both studies could indicate a relatively low prevalence of methicillin resistance in S. pseudintermedius among healthy canine populations, at least in the sampled regions. It may also suggest that MRSP carriage is more closely associated with clinical infections [30] or prior antimicrobial exposure, which were not present in the healthy dogs studied. The current understanding of the epidemiology, zoonotic potential, and antimicrobial resistance patterns of S. pseudintermedius in healthy canine carriers remains limited. Given the implications for both veterinary and public health, further investigations are essential to better characterise and address these critical areas [29]. In this study, the S. pseudintermedius strains isolated from dogs with otitis externa exhibited a more diverse and extensive antimicrobial resistance profile compared to those isolated from clinically healthy dogs. Although the proportion of strains susceptible to all tested antimicrobials was relatively similar between the two groups (38.1% in dogs with otitis externa vs. 40.8% in healthy dogs), resistance to tetracycline, penicillin, and clindamycin was more frequently observed among pathogenic strains. Notably, MRSP strains were exclusively isolated from dogs with otitis externa. All isolates were susceptible to antibiotics reserved for human medicine—such as linezolid, teicoplanin, vancomycin, and tigecycline—which were included in the testing panel due to the zoonotic potential of S. pseudintermedius. No resistance was observed to fusidic acid either. These findings support the notion that S. pseudintermedius strains isolated from both healthy and diseased dogs may harbour antimicrobial resistance and pose potential risks for zoonotic transmission, although strains associated with otitis externa tend to exhibit more frequent and complex resistance patterns. Recent research has shown that S. pseudintermedius, particularly methicillin-resistant strains (MRSP), may pose a zoonotic risk. Sequence types such as ST45, ST71, and ST121 were detected in both companion animals and human clinical samples, and wholegenome comparisons revealed high similarity between isolates, suggesting possible recent interspecies transmission [31]. Genomic analysis revealed notable diversity, including 23 STs among animal-derived strains and ten novel variants. Most isolates carried common resistance genes like mecA and blaZ, along with others conferring resistance to aminoglycosides, macrolides, and tetracyclines. Virulence factors such as sps, ica, and leukotoxin genes were also present and appeared to vary by sequence type, suggesting host adaptation [31]. While no direct correlation between host and ST was found, the genetic overlap between isolates from animals and humans highlights the zoonotic potential of MRSP and supports the need for One Health surveillance strategies [31]. Mobile genetic elements, such as SCCmec types III, IVg, V, and VII, were identified across MRSP isolates and played a key role in the dissemination of resistance genes, particularly mecA. Specific point mutations associated with fluoroquinolone resistance (e.g., grlA S80I and gyrA S84L) were frequently observed, especially in ST71 and ST339. These genomic features, alongside the presence of biocide resistance and virulence-associated genes, underline the adaptability of S. pseudintermedius and its potential to persist in both veterinary and human environments [32]. Moreover, the recent literature provides additional context that complements our findings. Regional studies have highlighted the clinical relevance of S. pseudintermedius and other staphylococcal species isolated from cutaneous and mucosal infections in companion animals [33,34]. Comprehensive reviews have described major epidemiological shifts in MRSP prevalence and explored alternative therapeutic strategies to address emerging resistance patterns [35]. Large-scale surveillance investigations from European veterinary clinics have further reported substantial MDR prevalence and complex co-resistance profiles among S. pseudintermedius isolates [36]. In addition, meta-analyses of canine otitis externa and pyoderma cases confirm a wide range of prevalence values across geographical regions [37], while recent studies emphasise the influence of host-related and managementassociated factors on the development and spread of antimicrobial resistance in canine populations [38]. The statistical analysis further reinforces the robustness of our findings, demonstrating significant differences in prevalence and antimicrobial resistance between isolates from diseased and clinically healthy dogs. The inclusion of p-values, FDR-adjusted q-values, and relative risk estimates provides quantitative evidence of these differences, underscoring their clinical and epidemiological relevance. 3.1 Limitations. This study has some limitations. The sampling was restricted to a single urban area, which may affect the generalizability of the findings. Furthermore, genetic characterisation of resistance determinants was not performed. Leading Article
Vetnuus | December 2025 11 3.2 Strengths. By documenting the presence of methicillin-resistant and multidrug-resistant S. pseudintermedius in dogs, this study highlights the zoonotic risks and reinforces the importance of prudent antimicrobial use within a One Health perspective. 4. Materials and Methods 4.1 Study Design. The study was conducted between 2022 and 2025 and involved the collection of samples from dogs diagnosed with otitis externa, as well as from clinically healthy dogs presented for routine procedures (such as sterilisation, vaccination, or deworming) at various veterinary clinics in Timisoara, Romania. 4.2 Sample Collection Samples were collected from 400 dogs presenting clinical signs of otitis externa and from 360 clinically healthy dogs. Bilateral ear swabs were taken using sterile cotton swabs, which were immediately placed in Amies (Oxoid, Basingstoke, UK) transport medium and stored at 4 ºC for a maximum of 24 h before processing. Samples were collected from 400 dogs presenting clinical signs of otitis externa and 360 clinically healthy dogs. Bilateral ear swabs were obtained using sterile cotton swabs, placed in Amies transport medium, and stored at 4 ºC for a maximum of 24 h before processing. Although samples were collected from both ears, only one S. pseudintermedius isolate per dog was included in the final analysis. This methodological choice was made to prevent pseudoreplication and overrepresentation of clonal isolates from the same individual, which could bias prevalence and antimicrobial resistance estimations. By focusing on a single representative isolate per host, the study ensured that epidemiological comparisons between diseased and healthy dogs reflected true host-level dynamics rather than intra-individual variability. In cases where multiple S. pseudintermedius isolates displaying identical antimicrobial resistance profiles were recovered from the same animal, only one representative isolate was retained to avoid data duplication and potential overestimation of strain prevalence. While this approach may have limited the detection of intra-host diversity and potential strain coexistence, it provided a more robust and accurate assessment of S. pseudintermedius occurrence and resistance patterns across the study population. This strategy aligns with standard epidemiological practices for prevalence and resistance studies, emphasising comparability between clinical and healthy cohorts. We acknowledge that phenotypic similarity does not necessarily imply clonal identity, as horizontal gene transfer or convergent evolution may result in similar resistance phenotypes among distinct strains. Therefore, future research incorporating molecular typing techniques, such as multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), or whole-genome sequencing (WGS), is warranted to explore intra-host diversity and confirm genetic relatedness among S. pseudintermedius isolates. 4.3 Bacterial Isolation and Species Identification Ear swab samples were cultured on two types of media: Columbia agar supplemented with 5% sheep blood ((Oxoid, Basingstoke, UK), a non-selective enriched medium that allows hemolysis evaluation, and Chapman agar (Mannitol Salt Agar; bioMérieux, Marcy-l’Étoile, France), a selective and differential medium for the isolation of halotolerant staphylococci and their differentiation based on mannitol fermentation. The plates were incubated aerobically at 35 ◦C for 18–24 h. Suspected colonies were selected based on characteristic morphology and subjected to Gram staining, catalase testing, and, when appropriate, coagulase testing. Suspect colonies were subcultured to obtain pure isolates, which were subsequently identified using MALDI-TOF mass spectrometry. Before antimicrobial susceptibility testing, presumptive S. pseudintermedius isolates were identified using MALDI-TOF MS (matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry; Bruker Daltonik, Bremen, Germany). Bacterial protein extracts were prepared following a standard ethanol/formic acid protocol. A volume of 1 µL from the prepared sample was placed on a MALDI target plate and subsequently layered with 1 µL of matrix solution composed of α-cyano-4-hydroxycinnamic acid (10 mg/ mL), prepared in 50% acetonitrile mixed with 2.5% trifluoroacetic acid. Spectra acquisition was performed using a Microflex™ mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany), and data were processed via MALDI BioTyper™ 3.0 software (Bruker Daltonik GmbH, Bremen, Germany). Species determination was based on spectral comparison against the manufacturer’s database. According to the scoring criteria provided by Bruker, values ≥ 2.0 were accepted as reliable species-level identification, whereas scores ranging from 1.7 to 1.99 were interpreted as indicative of genus-level classification [39]. Quality control (QC) for MALDI-TOF identification was initially performed using Staphylococcus aureus ATCC 25923 as a general control strain, in accordance with manufacturer recommendations. To further ensure the accuracy of species identification, a representative subset of isolates was re-analysed using the wellcharacterised S. pseudintermedius DSM 21284 reference strain as a species-specific QC. The results confirmed the identity of all isolates originally included in the study, thereby reinforcing the robustness of the identification procedure. Moreover, the Bruker Biotyper database used in this study contained manufacturer-validated protein spectra for S. pseudintermedius, ensuring accurate and reliable identification. The Biotyper database used included manufacturer-validated protein spectra for S. pseudintermedius. 4.4 Antimicrobial Susceptibility Testing (AST) Antimicrobial susceptibility was assessed with the VITEK® 2 Compact system (bioMérieux, Marcy-l’Étoile, France), in line with the manufacturer’s recommendations. Initially, pure bacterial colonies were isolated, and suspensions were made in sterile saline, with turbidity adjusted to correspond to the 0.5 McFarland standard. To evaluate resistance, specific cards for Gram-positive strains (VITEK® AST-GP79; bioMérieux, Marcy-l’Étoile, France) were employed [40]. Antimicrobial susceptibility profiling was performed using 14 antimicrobial agents belonging to 11 different classes. The tested substances included: penicillin and oxacillin (β-lactams); gentamicin (aminoglycosides); tetracycline (tetracyclines); ciprofloxacin and moxifloxacin (fluoroquinolones); erythromycin (macrolides); clindamycin (lincosamides); linezolid (oxazolidinones); teicoplanin and vancomycin (glycopeptides); fusidic acid (fusidanes); tigecycline (glycylcyclines); and trimethoprim–sulfamethoxazole (sulfonamides + pyrimidines). Leading Article >>>12
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