Department: Pathobiology and Population Sciences

Campus: Hawkshead

Research Groups: Antimicrobial Resistance, Host-Pathogen Interactions and Vaccinology, IRLFS (Research Programme)

Luca is Professor of Veterinary Bacteriology in the Pathobiology & Population Sciences department at the Royal Veterinary College.

Luca received his DVM from the Faculty of Veterinary Medicine of the University of Pisa (Italy) in 1994. He developed his career as a microbiologist in Denmark, where he completed his PhD in Veterinary Microbiology at the Royal Veterinary and Agricultural University in 2000 and became Professor at the University of Copenhagen in 2012. Since 2005, he is de facto Diplomate of the European College of Veterinary Public Health (ECVPH). He joined the Royal Veterinary College in December 2018 and continues to work half-time for the University of Copenhagen as Professor on One Health Antimicrobial Resistance. Among his honorary offices, Luca is the chair of the Therapeutic Guidelines Group in the World Small Animal Veterinary Association (WSAVA, and the Science Officer of the Veterinary Microbiology Group in the European Society for Clinical Microbiology and Infectious Diseases (ESCMID,

Luca is a One Health microbiologist specialized in antimicrobial resistance. His research encompasses molecular, epidemiological and clinical aspects of antimicrobial resistance, ranging from the origins of antimicrobial resistance to the discovery of new antibacterial strategies. Among the highlights, his research has contributed to a better understanding of the environmental origins of some of the most feared resistance determinants in human medicine, namely glycopeptide resistance operons in Gram-positive bacteria and carbapenemase-encoding genes in Gram-negative bacteria. Furthermore, his work has shed lights into the evolution and transmission patterns of plasmids encoding extended-spectrum β-lactamase (ESBL) across different animal species, and led to the identification of microbial, host and farm-related factors enhancing pig colonization and transmission of methicillin-resistant Staphylococcus aureus (MRSA). His current research utilizes cutting-edge technologies based on Next Generation Sequencing (RNA Seq, Tna Seq and shotgun metagenomics) to identify drug targets for antibiotic potentiation and to assess the effects of antibiotics and alternatives to antibiotics (e.g. phages, probiotics, prebiotics and immunostimulants) on the gut microbiome.

Luca is the coordinator of a large EU Innovation Action project on Alternatives to Veterinary Antimicrobials (AVANT, 2020-2024) involving 8 industries, 5 universities and the Federation of Veterinarians of Europe (FVE). He is also a partner in the Marie Curie Innovative Training Network (ITN) entitled "Combatting Antimicrobial Resistance Network" (CARTNET, 2018-2022) and the JPIAMR Global Antimicrobial Resistance Platform for ONE Burden Estimates (GAP-ONE, 2019-2020). Among his past projects, he was Principal Investigator of the University of Copenhagen Research Centre for Control of Antibiotic Resistance (UC-Care, 2012-2016), coordinated  the Marie Curie ITN TRAIN-ASAP (2012-2016) and participated in several other EU-funded projects such as PILGRIM (2009-2011), EvoTAR (2011-2015) and CALLISTO (2012-2015). 

Publications in peer-reviewed scientific journals:

  1. Møller TSB, Liu G, Hartman HB, Rau MH, Mortensen S, Thamsborg K, Johansen AE, Sommer MOA, Guardabassi L, Poolman MG, Olsen JE. Global responses to oxytetracycline treatment in tetracycline-resistant Escherichia coli. 
    Sci Rep. 2020 May 21;10(1):8438. doi: 10.1038/s41598-020-64995-1.

  2. Pirolo M, Sieber RN, Moodley A, Visaggio D, Artuso I, Gioffrè A, Casalinuovo F, Spatari G, Guardabassi L, Stegger M, Visca P.
    Local and transboundary transmission of methicillin-resistant Staphylococcus aureus sequence type 398 through pig trading. 
    Appl Environ Microbiol. 2020 May 1:AEM.00430-20. doi: 10.1128/AEM.00430-20.

  3. Lhermie G, La Ragione RM, Weese JS, Olsen JE, Christensen JP, Guardabassi L.
    Indications for the use of highest priority critically important antimicrobials in the veterinary sector.
    J Antimicrob Chemother. 2020 Apr 2:dkaa104. doi: 10.1093/jac/dkaa104. [Review]

  4. Skov R, Varga A, Matuschek E, Åhman J, Bemis D, Bengtsson B, Sunde M, Humphries R, Westblade L, Guardabassi L, Kahlmeter G 
    EUCAST disc diffusion criteria for the detection of mecA-Mediated β-lactam resistance in Staphylococcus pseudintermedius: oxacillin versus cefoxitin.  .Clin Microbiol Infect. 2020 Jan;26(1):122.e1-122.e6. doi: 10.1016/j.cmi.2019.05.002.

  5. Espinosa-Gongora C, Jessen LR, Kieler IN, Damborg P, Bjørnvad CR, Gudeta DD, Pires Dos Santos T, Sablier-Gallis F, Sayah-Jeanne S, Corbel T, Nevière A, Hugon P, Saint-Lu N, de Gunzburg J, Guardabassi L 
    Impact of oral amoxicillin and amoxicillin/clavulanic acid treatment on bacterial diversity and β-lactam resistance in the canine faecal microbiota. J Antimicrob Chemother. 2020 Feb 1;75(2):351-361. 

  6. Wegener A, Damborg P, Guardabassi L, Moodley A, Mughini-Gras L, Duim B, Wagenaar JA, Broens EM.
    Specific staphylococcal cassette chromosome mec (SCCmec) types and clonal complexes are associated with low-level amoxicillin/clavulanic acid and cefalotin resistance in methicillin-resistant Staphylococcus pseudintermedius.  J Antimicrob Chemother. 2020 Mar 1;75(3):508-511. doi: 10.1093/jac/dkz509.

  7. Anjum M, Madsen JS, Nesme J, Jana B, Wiese M, Jasinskyte D, Nielsen DS, Sørensen SJ, Dalsgaard A, Moodley A, Bortolaia V, Guardabassi L. 2019. Fate of CMY-2-encoding plasmids introduced into the human fecal microbiota by exogenous Escherichia coli. Antimicrob Agents Chemother [Epub ahead of print].
  8. Skov R, Varga A, Matuschek E, Åhman J, Bemis D, Bengtsson B, Sunde M, Humphries R, Westblade L, Guardabassi L, Kahlmeter G. 2019. EUCAST disc diffusion criteria for the detection of mecA-Mediated β-lactam resistance in Staphylococcus pseudintermedius: oxacillin versus cefoxitin. Clin Microbiol Infect [Epub ahead of print]
  9. Guardabassi L, Moodley A, Williams A, Stegger M, Damborg P, Halliday-Simmonds I, Butaye P. 2019. High Prevalence of USA300 Among Clinical Isolates of Methicillin-Resistant Staphylococcus aureuson St. Kitts and Nevis, West Indies. Front Microbiol 10:1123.
  10. Weese JS, Blondeau J, Boothe D, Guardabassi L, Gumley N, Papich M, Jessen LR, Lappin M, Rankin S, Westropp JL, Sykes J. 2019. International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J 247:8-25.
  11. Greco I, Hansen JE, Jana B, Molchanova N, Oddo A, Thulstrup PW, Damborg P, Guardabassi L, Hansen PR.2019. Structure-Activity Study, Characterization, and Mechanism of Action of an Antimicrobial Peptoid D2 and Its d- and l-Peptide Analogues. Molecules 24(6). pii: E1121.
  12. Baker KR, Jana B, Hansen AM, Vissing KJ, Nielsen HM, Franzyk H, Guardabassi L. 2019. Repurposing azithromycin and rifampicin against Gram-negative pathogens by combination with peptide potentiators. Int J Antimicrob Agents 53:868:872.
  13. Greco I, Plahn Emborg A, Jana B, Molchanova N, Oddo A, Damborg P, Guardabassi L, Hansen PR. 2019. Characterization, mechanism of action and optimization of activity of a novel peptide-peptoid hybrid against bacterial pathogens involved in canine skin infectionsSci Rep 9: 3679.
  14. Magnowska Z, Jana B, Brochmann RP, Hesketh A, Lametsch R, De Gobba C, Guardabassi L
    Carprofen-induced depletion of proton motive force reverses TetK-mediated doxycycline resistance in methicillin-resistant Staphylococcus pseudintermedius  Sci Rep. 2019 Nov 28;9(1):17834. doi: 10.1038/s41598-019-54091-4
  15. Brochmann PR, Hesketh A, Jana B, Brodersen GH, Guardabassi L. 2018. Transcriptome analysis of extended-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus exposed to cefotaximeSci Rep 8: 16076.
  16. Moodley A, Kot W, Nälgård S, Jakociune D, Neve H, Hansen LH, Guardabassi L, Vogensen FK. 2019. Isolation and characterization of bacteriophages active against methicillin-resistant Staphylococcus pseudintermedius. Res Vet Sci 122:81-85.
  17. Brochmann PR, Hesketh A, Jana B, Brodersen GH, Guardabassi L. 2018. Transcriptome analysis of extended-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus exposed to cefotaxime. Sci Rep 8:16076.
  18. Guardabassi L, Apley M, Olsen JE, Toutain PL, Weese S. 2018. Optimization of Antimicrobial Treatment to Minimize Resistance Selection. Microbiol Spectr 6(3).
  19. Larsen RF, Boysen L, Jessen LR, Guardabassi L, Damborg P. 2018. Diversity of Staphylococcus pseudintermedius in carriage sites and skin lesions of dogs with superficial bacterial folliculitis: potential implications for diagnostic testing and therapy. Vet Dermatol [Epub ahead of print].
  20. Loeffler A, Morris DO, Davis MF, Guardabassi L, Weese S. 2018. Response to "A concern with the clinical consensus guidelines on meticillin-resistant staphylococci". Vet Dermatol 29: 175.
  21. Anjum M, Madsen JS, Espinosa-Gongora C, Jana B, Wiese M, Nielsen DS, Sørensen SJ, Moodley A, Bortolaia V, Guardabassi L. 2018. A culture-independent method for studying transfer of IncI1 plasmids from wild-type Escherichia coli in complex microbial communities. J Microbiol Methods 152:18-26.
  22. Klitgaard RN, Jana B, Guardabassi L, Nielsen KL, Løbner-Olesen A. 2018. DNA Damage Repair and Drug Efflux as Potential Targets for Reversing Low or Intermediate Ciprofloxacin Resistance in E. coli K-12. Front Microbiol 9:1438.
  23. Niero G, Bortolaia V, Vanni M, Intorre L, Guardabassi L, Piccirillo A. 2018.High diversity of genes and plasmids encoding resistance to third-generation cephalosporins and quinolones in clinical Escherichia coli from commercial poultry flocks in Italy. Vet Microbiol 216:93-98.
  24. Onwugamba FC, Fitzgerald JR, Rochon K, Guardabassi L, Alabi A, Kühne S, Grobusch MP, Schaumburg F. 2018. The role of 'filth flies' in the spread of antimicrobial resistance. Travel Med Infect Dis 22:8-17.
  25. Sørensen TM, Bjørnvad CR, Cordoba G, Damborg P, Guardabassi L, Siersma V, Bjerrum L, Jessen LR. 2018. Effects of diagnostic work-up on medical decision-making for canine urinary tract infection: an observational study in Danish small animal practices. J Vet Intern Med 32:743-751.
  26. Saeed K, Gould I, Espositio S, Ahmad-Saeed N, Ahmed SS, Alp E, Bal AM, Bassetti M, Bonnet E, Chan M, Coombs G, Dancer SJ, David MZ, De Simone G, Dryden M, Guardabassi L, Hanitsch LG, Hijazi K, Krüger R, Lee A, Leistner R, Pagliano P, Righi E, Schneider-Burrus S, Skov RL, Tattevin P, Van Wamel W, Vos MC, Voss A; International Society of Chemotherapy. 2018. Panton-Valentine leukocidin-positive Staphylococcus aureus: a position statement from the International Society of Chemotherapy. Int J Antimicrob Agents 51:16-25.
  27. Baker, K R; Siguroardottir, H H; Jana, B; Guardabassi, L
    Cephem Potentiation by Inactivation of Nonessential Genes Involved in Cell Wall Biogenesis of β-Lactamase-Producing Escherichia coli, ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 61(3): e01773-16. (2017)
  28. Ventrella G, Moodley A, Grandolfo E, Parisi A, Corrente M, Buonavoglia D, Guardabassi L. 2017. Frequency, antimicrobial susceptibility and clonal distribution of methicillin-resistant Staphylococcus pseudintermedius in canine clinical samples submitted to a veterinary diagnostic laboratory in Italy: A 3-year retrospective investigation. Vet Microbiol 211:103-106.
  29. Bateman MD, de Vries SPW, Gupta S, Guardabassi L, Cavaco LM, Grant AJ, Holmes MA. 2017. Genome and plasmid sequences of Escherichia coli KV7, an extended-spectrum β-lactamase isolate derived from feces of a healthy pig. Genome Announc 5: e00595-17.
  30. Yassin AK, Gong J, Kelly P, Lu G, Guardabassi L, Wei L, Han X, Qiu H, Price S, Cheng D, Wang C. 2017. Antimicrobial resistance in clinical Escherichia coli isolates from poultry and livestock, China. PLoS One 12:e0185326.
  31. Guardabassi L. 2017. Antimicrobial resistance: a global threat with remarkable geographical differences. N Z Vet J. 65:57-59.
  32. Jana B, Cain AK, Doerrler WT, Boinett CJ, Fookes MC, Parkhill J, Guardabassi L. 2017. The secondary resistome of multidrug-resistant Klebsiella pneumoniae. Sci Rep 7:42483.
  33. Lappin MR, Blondeau J, Booth D, Breitschwerdt EB, Guardabassi L, Lloyd DH, Papich MG, Rankin SC, Sykes JE, Turnidge J, Weese JS. 2017. Antimicrobial use guidelines for treatment of respiratory tract disease in dogs and cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases. J Vet Intern Med 31:279-294.
  34. Guardabassi L, Damborg P, Stamm I, Kopp PA, Broens EM, Toutain PL, ESCMID Study Group for Veterinary Microbiology. 2017. Diagnostic microbiology in veterinary dermatology: present and future. Vet Dermatol 28:146-e30.
  35. Schoster A, Staempfli HR, Guardabassi L, Jalali M, Weese JS. 2017. Comparison of the fecal bacterial microbiota of healthy and diarrheic foals at two and four weeks of life. BMC Vet Res 13(1):144.
  36. Morris DO, Loeffler A, Davis MF, Guardabassi L, Weese JS. 2017. Recommendations for approaches to meticillin-resistant staphylococcal infections of small animals: diagnosis, therapeutic considerations and preventative measures.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 28:304-e69.
  37. Islam MZ, Espinosa-Gongora C, Damborg P, Sieber RN, Munk R, Husted L, Moodley A, Skov R, Larsen J, Guardabassi L. 2017. Horses in Denmark are a reservoir of diverse clones of methicillin-resistant and -susceptible Staphylococcus aureus. Front Microbiol 8:543.
  38. Rolo J, Worning P, Boye Nielsen J, Sobral R, Bowden R, Bouchami O, Damborg P, Guardabassi L, Perreten V, Westh H, Tomasz A, de Lencastre H, Miragaia M. 2017. Evidence for the evolutionary steps leading to mecA-mediated β-lactam resistance in staphylococci. PLoS Genet. 13:e1006674.
  39. Rolo J, Worning P, Nielsen JB, Bowden R, Bouchami O, Damborg P, Guardabassi L, Perreten V, Tomasz A, Westh H, de Lencastre H, Miragaia M. 2017. Evolutionary origin of the Staphylococcal Cassette Chromosome mec (SCCmec). Antimicrob Agents Chemother 61: e02302-16.
  40. Gudeta DD, Bortolaia V, Pollini S, Docquier JD, Rossolini GM, Amos GC, Wellington EM, Guardabassi L. 2016. Expanding the Repertoire of Carbapenem-Hydrolyzing Metallo-ß-Lactamases by Functional Metagenomic Analysis of Soil Microbiota. Front Microbiol 7:1985.
  41. Baker KR, Sigurðardóttir HH, Jana B, Guardabassi L. 2016. Cephem potentiation by inactivation of nonessential genes involved in cell wall biogenesis of β-lactamase-producing Escherichia coli. Antimicrob Agents Chemother 61: e01773-16.
  42. Sadaka C, Kanellos T, Guardabassi L, Boucher J, Watts JL. 2016. Evaluation of veterinary-specific interpretive criteria for susceptibility testing of Streptococcus equi subspecies equi with trimethoprim-sulfamethoxazole and trimethoprim-sulfadiazine. J Clin Microbiol 55:326-330.
  43. Sørensen TM, Jensen AB, Damborg P, Bjørnvad CR, Guardabassi L, Jessen LR. 2016. Evaluation of different sampling methods and criteria for diagnosing canine urinary tract infection by quantitative bacterial culture. Vet J 216:168-73.
  44. Marques C, Gama LT, Belas A, Bergström K, Beurlet S, Briend-Marchal A, Broens EM, Costa M, Criel D, Damborg P, van Dijk MA, van Dongen AM, Dorsch R, Espada CM, Gerber B, Kritsepi-Konstantinou M, Loncaric I, Mion D, Misic D, Movilla R, Overesch G, Perreten V, Roura X, Steenbergen J, Timofte D, Wolf G, Zanoni RG, Schmitt S, Guardabassi L, Pomba C. 2016. European multicenter study on antimicrobial resistance in bacteria isolated from companion animal urinary tract infections. BMC Vet Res 12:213.
  45. Espinosa-Gongora C, Larsen N, Schønning K, Fredholm M, Guardabassi L. 2016. Differential analysis of the nasal microbiome of pig carriers or non-carriers of Staphylococcus aureusPLoS One 11:e0160331.
  46. Pires Dos Santos T, Damborg P, Moodley A, Guardabassi L. 2016. Systematic Review on global epidemiology of methicillin-resistant Staphylococcus pseudintermedius: inference of population structure from multilocus sequence typing data. Front Microbiol 7:1599.
  47. Baker KR, Jana B, Franzyk H, Guardabassi L. 2016. A high-throughput approach to identify compounds that impair envelope integrity in Escherichia coliAntimicrob Agents Chemother 60:5995-6002.
  48. Damborg P, Moodley A, Aalbæk B, Ventrella G, Dos Santos TP, Guardabassi L. 2016. High genotypic diversity among methicillin-resistant Staphylococcus pseudintermedius isolated from canine infections in Denmark. BMC Vet Res 12:131.
  49. Brochmann RP, Helmfrid A, Jana B, Magnowska Z, Guardabassi L. 2016. Antimicrobial synergy between carprofen and doxycycline against methicillin-resistant Staphylococcus pseudintermedius ST71. BMC Vet Res 12:126.
  50. Møller TS, Rau MH, Bonde CS, Sommer MO, Guardabassi L, Olsen JE. 2016. Adaptive responses to cefotaxime treatment in ESBL-producing Escherichia coli and the possible use of significantly regulated pathways as novel secondary targets. J Antimicrob Chemother 71:2449-59.
  51. Hansen KH, Bortolaia V, Nielsen CA, Nielsen JB, Schønning K, Agersø Y, Guardabassi L. 2016. Host-specific patterns of genetic diversity among IncI1-Iγ and IncK plasmids encoding CMY-2 β-lactamase in Escherichia coli isolates from humans, poultry meat, poultry and dogs in Denmark. Appl Environ Microbiol 82:4705-14.
  52. Møller TS, Overgaard M, Nielsen SS, Bortolaia V, Sommer MO, Guardabassi L, Olsen JE. 2016. Relation between tetR and tetA expression in tetracycline resistant Escherichia coliBMC Microbiol 16:39.
  53. Gudeta DD, Bortolaia V, Jayol A, Poirel L, Nordmann P, Guardabassi L. 2016. Chromobacterium spp. harbour Ambler class A β-lactamases showing high identity with KPC. J Antimicrob Chemother. 71:1493-6.
  54. Schoster A, Guardabassi L, Staempfli HR, Abrahams M, Jalali M, Weese JS. 2016. The longitudinal effect of a multi-strain probiotic on the intestinal bacterial microbiota of neonatal foals. Equine Vet J 48:689-696.
  55. Bortolaia V, Espinosa-Gongora C, Guardabassi L. 2016. Human health risks associated with antimicrobial-resistant enterococci and Staphylococcus aureus on poultry meat. Clin Microbiol Infect 22:130-40.
  56. Damborg P, Broens EM, Chomel BB, Guenther S, Pasmans F, Wagenaar JA, Weese JS, Wieler LH, Windahl U, Vanrompay D, Guardabassi L. 2016. Bacterial zoonoses transmitted by household pets: state-of-the-art and future perspectives for targeted research and policy actions. J Comp Pathol. 155(Suppl 1):S27-40.
  57. Cito F, Rijks J, Rantsios AT, Cunningham AA, Baneth G, Guardabassi L, Kuiken T, Giovannini A. 2016. Prioritization of companion animal transmissible diseases for policy intervention in Europe. J Comp Pathol 155(Suppl 1):S18-26.
  58. Katakweba AS, Muhairwa AP, Espinosa-Gongora C, Guardabassi L, Mtambo MM, Olsen JE. 2016. spa typing and antimicrobial resistance of Staphylococcus aureus from healthy humans, pigs and dogs in Tanzania. J Infect Dev Ctries 10:143-8.

Luca teaches microbiology on multiple courses, including BVetMed. He also supervises graduate PhD students with theses related to veterinary bacteriology.

Luca is an internationally recognized specialist in clinical microbiology and has contributed to numerous ongoing education activities in antimicrobial stewardship targeting veterinary practitioners and nurses. He is a member of the Antimicrobial Guidelines Working International Society for Companion Animal Infectious Diseases (ISCAID) and participates in other national and international expert groups dedicated to the development of antibiotic use guidelines for companion animal practice.

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