{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:56:33Z","timestamp":1787028993850,"version":"build-2736575974"},"reference-count":51,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,5,4]],"date-time":"2025-05-04T00:00:00Z","timestamp":1746316800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Kytococcus belongs to the family Kytococcaceae, in the order Micrococcales, in the class Actinomycetes, and the phylum Actinomycetota. Kytococcus are aerobic, Gram-positive, non-spore forming bacteria that form coccoid, non-motile, non-encapsulated cells, and their colonies on agar have a yellow color. Infections by these species are increasingly identified nowadays. This narrative review aimed to present all available cases of Kytococcus spp. infections in humans, emphasizing data on the epidemiology, antimicrobial resistance, antimicrobial treatment, and mortality. A narrative review based on a literature search of the PubMed\/MedLine and Scopus databases was performed. Results: In total, 26 articles providing data on 30 patients with Kytococcus spp. infections were included in this analysis. The median age was 59.5 years, while 56.7% were male. The presence of a prosthetic cardiac valve was the main predisposing factor in 36.7% of patients (100% among those with infective endocarditis), while immunosuppression due to underlying hematological malignancy under chemotherapy was the second most common. Bacteremia was the most common type of infection, with infective endocarditis being the most common subtype in this infection type, while respiratory tract infections and osteoarticular infections were also relatively common. K. schroeteri was the most commonly identified species. Microbial identification required the use of advanced molecular techniques such as 16s rRNA sequencing in most cases. Kytotoccus spp. was resistant to all beta-lactams with the exception of carbapenems and macrolides. The most commonly used antimicrobials were vancomycin and rifampicin. Mortality was significant (30%). Due to the potential of Kytotoccus spp. to cause infective endocarditis in patients with prosthetic cardiac valves and respiratory tract infections with concomitant bacteremia in patients with hematological malignancy under chemotherapy along with the difficulties in pathogen identification, clinicians and laboratory personnel should consider this pathogen in the differential diagnosis in patients with typical predisposing factors and clinical presentation, especially when traditional microbiological techniques are used for pathogen identification.<\/jats:p>","DOI":"10.3390\/microorganisms13051072","type":"journal-article","created":{"date-parts":[[2025,5,4]],"date-time":"2025-05-04T20:09:14Z","timestamp":1746389354000},"page":"1072","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Kytococcus Species Infections in Humans\u2014A Narrative Review"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1082-5674","authenticated-orcid":false,"given":"Petros","family":"Ioannou","sequence":"first","affiliation":[{"name":"School of Medicine, University of Crete, 71003 Heraklion, Greece"},{"name":"Internal Medicine Department, University Hospital of Heraklion, 71110 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eleni","family":"Kampanieri","sequence":"additional","affiliation":[{"name":"Internal Medicine Department, General Hospital of Chania, 73300 Chania, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-6443-548X","authenticated-orcid":false,"given":"Stergos","family":"Koukias","sequence":"additional","affiliation":[{"name":"Internal Medicine Department, Venizeleio General Hospital, 71409 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stella","family":"Baliou","sequence":"additional","affiliation":[{"name":"School of Medicine, University of Crete, 71003 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3695-0759","authenticated-orcid":false,"given":"Andreas G.","family":"Tsantes","sequence":"additional","affiliation":[{"name":"Laboratory of Hematology and Blood Bank Unit, \u201cAttikon\u201d University Hospital, School of Medicine, National and Kapodistrian University of Athens, 12462 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0255-5926","authenticated-orcid":false,"given":"Diamantis","family":"Kofteridis","sequence":"additional","affiliation":[{"name":"School of Medicine, University of Crete, 71003 Heraklion, Greece"},{"name":"Internal Medicine Department, University Hospital of Heraklion, 71110 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"682","DOI":"10.1099\/00207713-45-4-682","article-title":"Taxonomic Dissection of the Genus Micrococcus: Kocuria Gen. Nov., Nesterenkonia Gen. Nov., Kytococcus Gen. Nov., Dermacoccus Gen. Nov., and Micrococcus Cohn 1872 Gen. Emend","volume":"45","author":"Stackebrandt","year":"1995","journal-title":"Int. J. Syst. Bacteriol."},{"key":"ref_2","first-page":"137","article-title":"The Phylogenetic Structure of the Coryneform Group of Bacteria","volume":"1","author":"Stackebrandt","year":"1980","journal-title":"Zentralblatt F\u00fcr Bakteriol. Abt Orig. C Allg. Angew. \u00d6kol. Mikrobiol."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Nouioui, I., Carro, L., Garc\u00eda-L\u00f3pez, M., Meier-Kolthoff, J.P., Woyke, T., Kyrpides, N.C., Pukall, R., Klenk, H.-P., Goodfellow, M., and G\u00f6ker, M. (2018). Genome-Based Taxonomic Classification of the Phylum Actinobacteria. Front. Microbiol., 9.","DOI":"10.3389\/fmicb.2018.02007"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"e01081-19","DOI":"10.1128\/MRA.01081-19","article-title":"Draft Genome Sequence of Kytococcus schroeteri Strain H01, Isolated from Human Skin","volume":"8","author":"Boukerb","year":"2019","journal-title":"Microbiol. Resour. Announc."},{"key":"ref_5","unstructured":"(2025, May 03). NCBI Taxonomy Browser for Kytococcus, Available online: https:\/\/www.ncbi.nlm.nih.gov\/Taxonomy\/Browser\/wwwtax.cgi?mode=Info&id=57499."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1493","DOI":"10.3201\/eid0911.020683","article-title":"Prosthetic Valve Endocarditis Due to Kytococcus schroeteri","volume":"9","author":"Becker","year":"2003","journal-title":"Emerg. Infect. Dis."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1007\/s00277-003-0831-x","article-title":"Fatal Hemorrhagic Pneumonia Caused by Infection Due to Kytococcus sedentarius\u2014A Pathogen or Passenger?","volume":"83","author":"Levenga","year":"2004","journal-title":"Ann. Hematol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"179","DOI":"10.3201\/eid1101.040761","article-title":"Kytococcus schroeteri Endocarditis","volume":"11","author":"Bouet","year":"2005","journal-title":"Emerg. Infect. Dis."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"E11","DOI":"10.1016\/j.jinf.2004.06.013","article-title":"Fatal Bacteremic Pneumonia","volume":"51","author":"Mohammedi","year":"2005","journal-title":"J. Infect."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1187","DOI":"10.1128\/JCM.44.3.1187-1189.2006","article-title":"Endocarditis Due to Kytococcus schroeteri: Case Report and Review of the Literature","volume":"44","author":"Mnif","year":"2006","journal-title":"J. Clin. Microbiol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/j.ijid.2007.06.011","article-title":"Kytococcus schroeteri, a Rare Agent of Endocarditis","volume":"12","author":"Renvoise","year":"2008","journal-title":"Int. J. Infect. Dis."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1007\/s00508-007-0903-3","article-title":"Kytococcus schroeteri: A Probably Underdiagnosed Pathogen Involved in Prosthetic Valve Endocarditis","volume":"120","author":"Aepinus","year":"2008","journal-title":"Wien. Klin. Wochenschr."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e153","DOI":"10.1016\/j.ijid.2008.09.004","article-title":"Kytococcus schroeteri Infection of a Ventriculoperitoneal Shunt in a Child","volume":"13","author":"Jourdain","year":"2009","journal-title":"Int. J. Infect. Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"bcr0620103064","DOI":"10.1136\/bcr.06.2010.3064","article-title":"Kytococcus schroeteri Prosthetic Valve Endocarditis","volume":"2010","author":"Yousri","year":"2010","journal-title":"BMJ Case Rep."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1099\/jmm.0.010454-0","article-title":"Postoperative Spondylodiscitis Due to Kytococcus schroeteri in a Diabetic Woman","volume":"59","author":"Jacquier","year":"2010","journal-title":"J. Med. Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"138","DOI":"10.1007\/s15010-009-9295-4","article-title":"Kytococcus schroeteri Pneumonia in Two Patients with a Hematological Malignancy","volume":"38","author":"Hodiamont","year":"2010","journal-title":"Infection"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"252","DOI":"10.3747\/pdi.2009.00086","article-title":"Peritoneal Dialysis-Associated Peritonitis Due to Kytococcus sedentarius","volume":"30","author":"Chaudhary","year":"2010","journal-title":"Perit. Dial. Int. J. Int. Soc. Perit. Dial."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1121","DOI":"10.1001\/archdermatol.2011.242","article-title":"Fatal Kytococcus schroeteri Infection with Crusted Papules and Distinctive Histologic Plump Tetrads","volume":"147","author":"Nagler","year":"2011","journal-title":"Arch. Dermatol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1077","DOI":"10.1177\/039139881203501206","article-title":"Vascular Homograft Use in a Femoropopliteal Rare Bacterial Infection Bypass","volume":"35","author":"Dainese","year":"2012","journal-title":"Int. J. Artif. Organs"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"750","DOI":"10.1099\/jmm.0.035493-0","article-title":"Kytococcus schroeteri Endocarditis Successfully Managed with Daptomycin: A Case Report and Review of the Literature","volume":"61","author":"Liu","year":"2012","journal-title":"J. Med. Microbiol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"522","DOI":"10.1128\/JCM.01245-11","article-title":"Pneumonia and Bacteremia Due to Kytococcus schroeteri","volume":"50","author":"Blennow","year":"2012","journal-title":"J. Clin. Microbiol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1007\/s15010-012-0250-9","article-title":"First Report of Chronic Implant-Related Septic Arthritis and Osteomyelitis Due to Kytococcus schroeteri and a Review of Human K. Schroeteri Infections","volume":"40","author":"Chan","year":"2012","journal-title":"Infection"},{"key":"ref_23","first-page":"217307","article-title":"Kytococcus schroeteri Bacteremia in a Patient with Hairy Cell Leukemia: A Case Report and Review of the Literature","volume":"2015","author":"Amaraneni","year":"2015","journal-title":"Case Rep. Infect. Dis."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1097\/01.ccm.0000510444.50180.91","article-title":"1771: Kytococcus bacteremia in a pediatric patient with myelodysplastic syndrome","volume":"44","author":"DeMartini","year":"2016","journal-title":"Crit. Care Med."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"e304","DOI":"10.1097\/INF.0000000000002014","article-title":"First Case of Bacteremia Caused by Kytococcus schroeteri in a Child With Congenital Adrenal Hyperplasia","volume":"37","author":"Bayraktar","year":"2018","journal-title":"Pediatr. Infect. Dis. J."},{"key":"ref_26","first-page":"6936472","article-title":"Postoperative Hardware-Related Infection from Kytococcus schroeteri: Its Association with Prosthetic Material and Hematological Malignancies\u2014A Report of a Case and Review of Existing Literature","volume":"2019","author":"Shah","year":"2019","journal-title":"Case Rep. Infect. Dis."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"230","DOI":"10.3390\/idr13010026","article-title":"Insight into Kytococcus schroeteri Infection Management: A Case Report and Review","volume":"13","author":"Bagelman","year":"2021","journal-title":"Infect. Dis. Rep."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Lim, K.R., Son, J.S., and Moon, S. (2021). Case Report of Infectious Spondylitis Caused by Kytococcus sedentarius. Medicina, 57.","DOI":"10.3390\/medicina57080797"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Zellner, A.A., Hischebeth, G.T., Molitor, E., Wirtz, D.C., and Randau, T.M. (2023). Periprosthetic Joint Infection Caused by Kytococcus schroeteri: The First Reported Case and a Review of the Literature. Diagn. Microbiol. Infect. Dis., 106.","DOI":"10.1016\/j.diagmicrobio.2023.115922"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.ijmmb.2022.09.001","article-title":"A Case of Kytococcus schroeteri Prosthetic Valve Endocarditis in a Patient with COVID-19 Infection","volume":"42","author":"Shah","year":"2023","journal-title":"Indian J. Med. Microbiol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e1344","DOI":"10.1097\/IPC.0000000000001344","article-title":"Kytococcus schroeteri: An Emerging Cause of Prosthetic Valve Endocarditis","volume":"22","author":"Pandey","year":"2024","journal-title":"Infect. Dis. Clin. Pract."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1016\/j.jiac.2019.10.019","article-title":"Half of \u201cMicrococcus Spp.\u201d Cases Identified by Conventional Methods Are Revealed as Other Life-Threatening Bacteria with Different Drug Susceptibility Patterns by 16S Ribosomal RNA Gene Sequencing","volume":"26","author":"Noguchi","year":"2020","journal-title":"J. Infect. Chemother. Off. J. Jpn. Soc. Chemother."},{"key":"ref_33","first-page":"e53176","article-title":"Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS","volume":"113","author":"Gunzer","year":"2016","journal-title":"J. Vis. Exp. JoVE"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2182","DOI":"10.1128\/JCM.00492-13","article-title":"Identification of Rare Pathogenic Bacteria in a Clinical Microbiology Laboratory: Impact of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry","volume":"51","author":"Seng","year":"2013","journal-title":"J. Clin. Microbiol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.mimet.2012.10.014","article-title":"Use of MALDI-TOF Mass Spectrometry for Identification of Bacteria That Are Difficult to Culture","volume":"92","author":"Biswas","year":"2013","journal-title":"J. Microbiol. Methods"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1001\/archinternmed.2008.603","article-title":"Clinical Presentation, Etiology, and Outcome of Infective Endocarditis in the 21st Century: The International Collaboration on Endocarditis-Prospective Cohort Study","volume":"169","author":"Murdoch","year":"2009","journal-title":"Arch. Intern. Med."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/j.amjcard.2025.02.023","article-title":"Epidemiological Profile and Mortality of Infective Endocarditis Over the Past Decade: A Systematic Review and Meta-Analysis of 133 Studies","volume":"244","author":"Tzoumas","year":"2025","journal-title":"Am. J. Cardiol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"21","DOI":"10.3947\/ic.2018.50.1.21","article-title":"Epidemiology, Microbiological and Clinical Features, Treatment, and Outcomes of Infective Endocarditis in Crete, Greece","volume":"50","author":"Papakonstantinou","year":"2018","journal-title":"Infect. Chemother."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Dropulic, L.K., and Lederman, H.M. (2016). Overview of Infections in the Immunocompromised Host. Microbiol. Spectr., 4.","DOI":"10.1128\/microbiolspec.DMIH2-0026-2016"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"S156","DOI":"10.1093\/infdis\/jiaa320","article-title":"Sepsis in Immunocompromised Patients Without Human Immunodeficiency Virus","volume":"222","author":"McCreery","year":"2020","journal-title":"J. Infect. Dis."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1182\/asheducation-2003.1.438","article-title":"Infections in Patients with Hematological Cancer: Recent Developments","volume":"2003","author":"Blijlevens","year":"2003","journal-title":"Hematology"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"5494","DOI":"10.7150\/jca.50802","article-title":"A Practical Update on the Epidemiology and Risk Factors for the Emergence and Mortality of Bloodstream Infections from Real-World Data of 3014 Hematological Malignancy Patients Receiving Chemotherapy","volume":"12","author":"Chen","year":"2021","journal-title":"J. Cancer"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1016\/j.jinf.2010.03.006","article-title":"The Microbiology of Chronic Osteomyelitis: Prevalence of Resistance to Common Empirical Anti-Microbial Regimens","volume":"60","author":"Sheehy","year":"2010","journal-title":"J. Infect."},{"key":"ref_44","first-page":"23","article-title":"Gram-Negative Bacteria as Emerging Pathogens Affecting Mortality in Skin and Soft Tissue Infections","volume":"22","author":"Ioannou","year":"2018","journal-title":"Hippokratia"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"316","DOI":"10.3747\/pdi.2011.00058","article-title":"Microbiology of Peritonitis in Peritoneal Dialysis Patients with Multiple Episodes","volume":"32","author":"Nessim","year":"2012","journal-title":"Perit. Dial. Int. J. Int. Soc. Perit. Dial."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"752","DOI":"10.1016\/j.jmii.2018.10.013","article-title":"Microbiology of Peritoneal Dialysis-Related Infection and Factors of Refractory Peritoneal Dialysis Related Peritonitis: A Ten-Year Single-Center Study in Taiwan","volume":"52","author":"Wang","year":"2019","journal-title":"J. Microbiol. Immunol. Infect. Wei Mian Yu Gan Ran Za Zhi"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/j.jvs.2020.12.071","article-title":"Microbial Evolution of Vascular Graft Infections in a Tertiary Hospital Based on Positive Graft Cultures","volume":"74","author":"Martins","year":"2021","journal-title":"J. Vasc. Surg."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1056\/NEJMoa1710926","article-title":"Oral versus Intravenous Antibiotics for Bone and Joint Infection","volume":"380","author":"Li","year":"2019","journal-title":"N. Engl. J. Med."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1684\/ejd.2014.2376","article-title":"Pitted Keratolysis in an Adolescent, Diagnosed Using Conventional and Molecular Microbiology and Successfully Treated with Fusidic Acid","volume":"24","author":"Papaparaskevas","year":"2014","journal-title":"Eur. J. Dermatol. EJD"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1159\/000512751","article-title":"Analysis of Kytococcus sedentarius Strain Isolated from a Dehumidifier Operating in a University Lecture Theatre: Systems for Aerobic Respiration, Resisting Osmotic Stress, and Sensing Nitric Oxide","volume":"31","author":"Alhadlaq","year":"2021","journal-title":"Microb. Physiol."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"20406223231173891","DOI":"10.1177\/20406223231173891","article-title":"Trends in Mortality from Infection among Patients with Hematologic Malignancies: Differences According to Hematologic Malignancy Subtype","volume":"14","author":"Yin","year":"2023","journal-title":"Ther. Adv. Chronic Dis."}],"container-title":["Microorganisms"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2607\/13\/5\/1072\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:26:55Z","timestamp":1760030815000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2607\/13\/5\/1072"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,4]]},"references-count":51,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2025,5]]}},"alternative-id":["microorganisms13051072"],"URL":"https:\/\/doi.org\/10.3390\/microorganisms13051072","relation":{},"ISSN":["2076-2607"],"issn-type":[{"value":"2076-2607","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,5,4]]}}}