{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,29]],"date-time":"2026-08-29T21:10:46Z","timestamp":1788037846942,"version":"build-2784847793"},"reference-count":42,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,7,26]],"date-time":"2025-07-26T00:00:00Z","timestamp":1753488000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"University of Zagreb School of Medicine","award":["10106-24-1294"],"award-info":[{"award-number":["10106-24-1294"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Background\/objectives: Proteus mirabilis is a frequent causative agent of urinary and wound infections in both community and hospital settings. It develops resistance to expanded-spectrum cephalosporins (ESCs) due to the production of extended-spectrum \u03b2-lactamases (ESBLs) or plasmid-mediated AmpC \u03b2-lactamases (p-AmpCs). Recently, carbapenem-resistant isolates of P. mirabilis emerged due to the production of carbapenemases, mostly belonging to Ambler classes B and D. Here, we report an outbreak of infections due to carbapenem-resistant P. mirabilis that were observed in a psychiatric hospital in Zagreb, Croatia. The characteristics of ESBL and carbapenemase-producing P. mirabilis isolates, associated with an outbreak, were analyzed. Materials and methods: The antibiotic susceptibility testing was performed by the disk-diffusion and broth dilution methods. The double-disk synergy test (DDST) and inhibitor-based test with clavulanic and phenylboronic acid were applied to screen for ESBLs and p-AmpCs, respectively. Carbapenemases were screened by the modified Hodge test (MHT), while carbapenem hydrolysis was investigated by the carbapenem inactivation method (CIM) and EDTA-carbapenem-inactivation method (eCIM). The nature of the ESBLs, carbapenemases, and fluoroquinolone-resistance determinants was investigated by PCR. Plasmids were characterized by PCR-based replicon typing (PBRT). Selected isolates were subjected to molecular characterization of the resistome by an Inter-Array Genotyping Kit CarbaResisit and whole-genome sequencing (WGS). Results: In total, 20 isolates were collected and analyzed. All isolates exhibited resistance to amoxicillin alone and when combined with clavulanic acid, cefuroxime, cefotaxime, ceftriaxone, cefepime, imipenem, ceftazidime\u2013avibactam, ceftolozane\u2013tazobactam, gentamicin, amikacin, and ciprofloxacin. There was uniform susceptibility to ertapenem, meropenem, and cefiderocol. The DDST and combined disk test with clavulanic acid were positive, indicating the production of an ESBL. The MHT was negative in all except one isolate, while the CIM showed moderate sensitivity, but only with imipenem as the indicator disk. Furthermore, eCIM tested positive in all of the CIM-positive isolates, consistent with a metallo-\u03b2-lactamase (MBL). PCR and sequencing of the selected amplicons identified VIM-1 and VIM-4. The Inter-Array Genotyping Kit CarbaResist and WGS identified \u03b2-lactam resistance genes blaVIM, blaCTX-M-15, and blaTEM genes; aminoglycoside resistance genes aac(3)-IId, aph(6)-Id, aph(3\u2033)-Ib, aadA1, armA, and aac(6\u2032)-IIc; as well as resistance genes for sulphonamides sul1 and sul2, trimethoprim dfr1, chloramphenicol cat, and tetracycline tet(J). Conclusions: This study revealed an epidemic spread of carbapenemase-producing P. mirabilis in two wards in a psychiatric hospital. Due to the extensively resistant phenotype (XDR), therapeutic options were limited. This is the first report of carbapenemase-producing P. mirabilis in Croatia.<\/jats:p>","DOI":"10.3390\/pathogens14080737","type":"journal-article","created":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T10:51:14Z","timestamp":1753699874000},"page":"737","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Outbreak Caused by VIM-1- and VIM-4-Positive Proteus mirabilis in a Hospital in Zagreb"],"prefix":"10.3390","volume":"14","author":[{"given":"Branka","family":"Bedeni\u0107","sequence":"first","affiliation":[{"name":"Biomedical Research Institute-BIMIS, University of Zagreb School of Medicine, 10000 Zagreb, Croatia"},{"name":"Clinical Department for Clinical Microbiology, Infection Control and Prevention, School of Medicine, University Hospital Center Zagreb, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1592-4559","authenticated-orcid":false,"given":"Gernot","family":"Zarfel","sequence":"additional","affiliation":[{"name":"Diagnostic and Research Institute for Hygiene, Microbiology and Environmental Medicine, Medical University Graz, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-6579-5089","authenticated-orcid":false,"given":"Josefa","family":"Luxner","sequence":"additional","affiliation":[{"name":"Diagnostic and Research Institute for Hygiene, Microbiology and Environmental Medicine, Medical University Graz, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6937-521X","authenticated-orcid":false,"given":"Andrea","family":"Grisold","sequence":"additional","affiliation":[{"name":"Diagnostic and Research Institute for Hygiene, Microbiology and Environmental Medicine, Medical University Graz, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marina","family":"Na\u0111","sequence":"additional","affiliation":[{"name":"University of Zagreb School of Medicine,10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maja","family":"Anu\u0161i\u0107","sequence":"additional","affiliation":[{"name":"Department of Clinical Microbiology, Dr Andrija \u0160tampar Teaching Institute of Public Health Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vladimira","family":"Ti\u010di\u0107","sequence":"additional","affiliation":[{"name":"Department of Clinical Microbiology, Dr Andrija \u0160tampar Teaching Institute of Public Health Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2365-8975","authenticated-orcid":false,"given":"Verena","family":"Dobretzberger","sequence":"additional","affiliation":[{"name":"Department of Molecular Diagnostics, Austrian Institute for Technology, 1210 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1301-6197","authenticated-orcid":false,"given":"Ivan","family":"Bari\u0161i\u0107","sequence":"additional","affiliation":[{"name":"Department of Molecular Diagnostics, Austrian Institute for Technology, 1210 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3282-0973","authenticated-orcid":false,"given":"Jasmina","family":"Vrane\u0161","sequence":"additional","affiliation":[{"name":"Department of Clinical Microbiology, Dr Andrija \u0160tampar Teaching Institute of Public Health Zagreb, 10000 Zagreb, Croatia"},{"name":"Department of Medical Microbiology and Parasitology, University of Zagreb School of Medicine, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Sanches, M.S., Silva, L.C., Silva, C.R.D., Montini, V.H., Oliva, B.H.D., Guidone, G.H.M., Nogueira, M.C.L., Menck-Costa, M.F., Kobayashi, R.K.T., and Vespero, E.C. (2023). Prevalence of Antimicrobial Resistance and Clonal Relationship in ESBL\/AmpC-Producing Proteus mirabilis Isolated from Meat Products and Community-Acquired Urinary Tract Infection (UTI-CA) in Southern Brazil. Antibiotics, 10.","DOI":"10.3390\/antibiotics12020370"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Li, Y., Yin, M., Fang, C., Fu, Y., Dai, X., Zeng, W., and Zhang, L. (2023). Genetic analysis of resistance and virulence characteristics of clinical multidrug-resistant Proteus mirabilis isolates. Front. Cell. Infect. Microbiol., 11.","DOI":"10.3389\/fcimb.2023.1229194"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Girlich, D., Bonnin, R.A., Dortet, L., and Naas, T. (2020). Genetics of Acquired Antibiotic Resistance Genes in Proteus spp. Front. Microbiol., 21.","DOI":"10.3389\/fmicb.2020.00256"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1098\/rstb.1980.0049","article-title":"The structure of \u03b2-lactamases","volume":"289","author":"Ambler","year":"1980","journal-title":"Philos. Trans. R. Soc. Lond. B Biol. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"657","DOI":"10.1128\/CMR.18.4.657-686.2005","article-title":"Extended-spectrum \u03b2-lactamases: A clinical update","volume":"18","author":"Paterson","year":"2005","journal-title":"Clin. Microbiol. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Cant\u00f3n, R., Gonz\u00e1lez-Alba, J.M., and Gal\u00e1n, J.C. (2012). CTX-M Enzymes: Origin and Diffusion. Front. Microbiol., 2.","DOI":"10.3389\/fmicb.2012.00110"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.drup.2016.09.002","article-title":"The rapid spread of carbapenem-resistant Enterobacteriaceae","volume":"9","author":"Potter","year":"2016","journal-title":"Drug Resist. Updat."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1185","DOI":"10.1099\/jmm.0.016964-0","article-title":"High prevalence and molecular characterization of extended-spectrum \u03b2-lactamase-producing Proteus mirabilis strains in southern Croatia","volume":"59","author":"Mohar","year":"2010","journal-title":"J. Med. Microbiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1007\/s00508-016-1005-x","article-title":"Emergence of multidrug-resistant Proteus mirabilis in a long-term care facility in Croatia","volume":"128","author":"Firis","year":"2016","journal-title":"Wien. Klin. Wochenschr."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1089\/mdr.2020.0002","article-title":"Molecular Characterization of \u03b2-Lactam Resistance and Antimicrobial Susceptibility to Possible Therapeutic Options of AmpC-Producing Multidrug-Resistant Proteus mirabilis in a University Hospital of Split, Croatia","volume":"27","author":"Soprek","year":"2021","journal-title":"Microb. Drug Resist."},{"key":"ref_11","unstructured":"European Committee for Antimicrobial Susceptibility Testing (2024, October 01). Breakpoint Tables for Interpretation of MICs and Zone Diameters. Version 12. Available online: http:\/\/www.eucast.org."},{"key":"ref_12","unstructured":"Clinical Laboratory Standard Institution (2018). Performance Standards for Antimicrobial Susceptibility Testing, Clinical and Laboratory Standards Institute. [28th ed.]."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1111\/j.1469-0691.2011.03570.x","article-title":"Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: An international expert proposal for interim standard definitions for acquired resistance","volume":"18","author":"Magiorakos","year":"2002","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"867","DOI":"10.1093\/clinids\/10.4.867","article-title":"Extended broad-spectrum beta-lactamases conferring transferable resistance to newer beta-lactam agents in Enterobacteriaceae: Hospital prevalence and susceptibility patterns","volume":"10","author":"Jarlier","year":"1988","journal-title":"Rev. Infect. Dis."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1128\/CMR.00036-08","article-title":"AmpC \u03b2-lactamases","volume":"22","author":"Jacoby","year":"2009","journal-title":"J. Clin. Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"MacDonald, J.W., and Chibabhai, V. (2019). Evaluation of the RESIST-4 O.K.N.V Immunochromatographic Lateral Flow Assay for the Rapid Detection of OXA-48, KPC, NDM and VIM Carbapenemases from Cultured Isolates. Access Microbiol., 1.","DOI":"10.1099\/acmi.0.000031"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4623","DOI":"10.1128\/JCM.41.10.4623-4629.2003","article-title":"Evaluation of the Hodge Test and the Imipenem-EDTA-double-disk Synergy Test for Differentiating Metallo-\u03b2-lactamase-producing Isolates of Pseudomonas spp. and Acinetobacter spp","volume":"41","author":"Lee","year":"2003","journal-title":"J. Clin. Microbiol."},{"key":"ref_18","unstructured":"CLSI (2021). Performance Standards for Antimicrobial Susceptibility Testing, M100, Clinical and Laboratory Standards Institute. [31st ed.]."},{"key":"ref_19","first-page":"203","article-title":"Molecular characterization by PCR restriction fragment polymorphism of TEM \u03b2-lactamases","volume":"134","author":"Arlet","year":"1995","journal-title":"FEMS Microbiol. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"398","DOI":"10.1007\/BF01690097","article-title":"Detection of genes coding for extended-spectrum SHV \u03b2-lactamases in clinical isolates by a molecular genetic method, and comparison with the E test","volume":"15","author":"Kayser","year":"1996","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1093\/jac\/dkh424","article-title":"Community and hospital spread of Escherichia coli producing CTX-M extended-spectrum \u03b2-lactamases in the UK","volume":"54","author":"Woodford","year":"2004","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1016\/S1473-3099(06)70599-0","article-title":"The worldwide emergence of plasmid-mediated quinolone resistance","volume":"6","author":"Robicsek","year":"2006","journal-title":"Lancet Infect. Dis."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.diagmicrobio.2010.12.002","article-title":"Multiplex PCR for Detection of Acquired Carbapenemases Genes. Diagn","volume":"70","author":"Poirel","year":"2011","journal-title":"Microbiol. Infect. Dis."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1016\/j.ijantimicag.2006.01.004","article-title":"Multiplex PCR for genes encoding prevalent OXA carbapenemases","volume":"27","author":"Woodford","year":"2006","journal-title":"Int. J. Antimicrob. Agents"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2153","DOI":"10.1128\/JCM.40.6.2153-2162.2002","article-title":"Detection of plasmid-mediated AmpC \u03b2-lactamase genes in clinical isolates by using multiplex PCR","volume":"40","author":"Hanson","year":"2002","journal-title":"J. Clin. Microbiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1093\/jac\/dki412","article-title":"Multiplex PCR for rapid detection of genes encoding CTX-M extended-spectrum \u03b2-lactamases","volume":"57","author":"Woodford","year":"2006","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_27","first-page":"161","article-title":"Diversity of CTX-M \u03b2-lactamases and Their Promoter Regions from Enterobacteriaceae Isolated in Three Parisian Hospitals","volume":"209","author":"Saladin","year":"2002","journal-title":"FEMS. Microbiol. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2640","DOI":"10.1093\/jac\/dks261","article-title":"Identification of acquired antimicrobial resistance genes","volume":"67","author":"Zankari","year":"2012","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_29","unstructured":"Lorian, V. (1986). The characterization of R plasmids and the detection of plasmid-specified genes. Antibiotics in Laboratory Medicine, Williams and Wilkins. [2nd ed.]."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/j.mimet.2005.03.018","article-title":"Identification of plasmids by PCR-based replicon typing","volume":"63","author":"Carattoli","year":"2005","journal-title":"J. Microbiol. Methods"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Carattoli, A., Seiffert, S.N., Schwendener, S., Perreten, V., and Endimiani, A. (2015). Differentiation of IncL and IncM Plasmids Associated with the Spread of Clinically Relevant Antimicrobial Resistance. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0123063"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Shaaban, M., Elshaer, S.L., and Abd El-Rahman, O.A. (2022). Prevalence of extended-spectrum \u03b2-lactamases, AmpC, and carbapenemases in Proteus mirabilis clinical isolates. BMC Microbiol., 11.","DOI":"10.1186\/s12866-022-02662-3"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"667","DOI":"10.1128\/JCM.01872-09","article-title":"Detecting VIM-1 production in Proteus mirabilis by an imipenem-dipicolinic acid double disk synergy test","volume":"48","author":"Miriagou","year":"2010","journal-title":"J. Clin. Microbiol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"4024","DOI":"10.1128\/AAC.00470-12","article-title":"Characterization of a transmissible plasmid encoding VEB-1 and VIM-1 in Proteus mirabilis","volume":"56","author":"Papagiannitsis","year":"2012","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"106060","DOI":"10.1016\/j.ijantimicag.2020.106060","article-title":"Clonal outbreak caused by VIM-4-producing Proteus mirabilis in a Greek tertiary-care hospital","volume":"56","author":"Protonotariou","year":"2020","journal-title":"Int. J. Antimicrob. Agents"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1089\/mdr.2016.0026","article-title":"Dissemination of a Multidrug-Resistant VIM-1- and CMY-99-Producing Proteus mirabilis Clone in Bulgaria","volume":"23","author":"Markovska","year":"2017","journal-title":"Microb. Drug. Resist."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Fritzenwanker, M., Falgenhauer, J., Hain, T., Imirzalioglu, C., Chakraborty, T., and Yao, Y. (2025). The Detection of Extensively Drug-Resistant Proteus mirabilis Strains Harboring Both VIM-; and VIM-75 Metallo-\u03b2-Lactamases from Patients in Germany. Microorganisms, 25.","DOI":"10.3390\/microorganisms13020266"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Bedeni\u0107, B., Brati\u0107, V., Mihaljevi\u0107, S., Luki\u0107, A., Vidovi\u0107, K., Reiner, K., Sch\u00f6enthaler, S., Bari\u0161i\u0107, I., Zarfel, G., and Grisold, A. (2023). Multidrug-Resistant Bacteria in a COVID-19 Hospital in Zagreb. Pathogens, 12.","DOI":"10.3390\/pathogens12010117"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2353310","DOI":"10.1080\/22221751.2024.2353310","article-title":"OXA-48-like carbapenemases in Proteus mirabilis\u2014Novel genetic environments and a challenge for detection","volume":"13","author":"Sattler","year":"2024","journal-title":"Emerg. Microbes. Infect."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"e00191-19","DOI":"10.1128\/AAC.00191-19","article-title":"Carbapenem-Susceptible OXA-23-Producing Proteus mirabilis in the French Community","volume":"63","author":"Potron","year":"2019","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Bonnin, R.A., Girlich, D., Jousset, A.B., Gauthier, L., Cuzon, G., and Bogaerts, P. (2020). A single Proteus mirabilis lineage from human and animal sources: A hidden reservoir of OXA-23 or OXA-58 carbapenemases in Enterobacterales. Sci. Rep., 8.","DOI":"10.1038\/s41598-020-66161-z"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Mendon\u00e7a, J., Guedes, C., Silva, C., S\u00e1, S., Oliveira, M., Accioly, G., Baylina, P., Barata, P., Pereira, C., and Fernandes, R. (2022). New CTX-M Group Conferring \u03b2-Lactam Resistance: A Compendium of Phylogenetic Insights from Biochemical, Molecular, and Structural Biology. Biology, 11.","DOI":"10.3390\/biology11020256"}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/14\/8\/737\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:16:39Z","timestamp":1760033799000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/14\/8\/737"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,26]]},"references-count":42,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2025,8]]}},"alternative-id":["pathogens14080737"],"URL":"https:\/\/doi.org\/10.3390\/pathogens14080737","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,26]]}}}