{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:31:09Z","timestamp":1787027469254,"version":"build-2736575974"},"reference-count":35,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2022,11,11]],"date-time":"2022-11-11T00:00:00Z","timestamp":1668124800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the research center at King Fahd Medical City, Riyadh, Internal Research Fund (IRF)","award":["019-051"],"award-info":[{"award-number":["019-051"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background: Whole-genome sequencing is one of the best ways to investigate resistance mechanisms of clinical isolates as well as to detect and identify circulating multi-drug-resistant (MDR) clones or sub-clones in a given hospital setting. Methods: Here, we sequenced 37 isolates of Acinetobacter baumannii, 10 Klebsiella pneumoniae, and 5 Pseudomonas aeruginosa collected from the biobank of the hospital setting of the King Fahad Medical City. Complete phenotypic analyses were performed, including MALDI-TOF identification and antibiotic susceptibility testing. After the genome assembly of raw data, exhaustive genomic analysis was conducted including full resistome determination, genomic SNP (gSNP) analysis, and comparative genomics. Results: Almost all isolates were highly resistant to all tested antibiotics, including carbapenems and colistin. Resistome analysis revealed many antibiotic resistance genes, including those with resistance to \u03b2-lactams, aminoglycosides, macrolides, tetracyclines, sulfamids, quinolones, and phenicols. In A. baumannii isolates, the endemic carbapenemase blaOXA-23 gene was detected in 36 of the 37 isolates. Non-synonymous mutations in pmrB were detected in almost all of the isolates and likely mediated colistin resistance. Interestingly, while classical analyses, such as MLST, revealed the predominance of an ST2 clone in A. baumannii isolates, the genomic analysis revealed the presence of five circulating sub-clones and identified several isolate transmissions between patients. In the 10 K. pneumoniae isolates, several resistance genes were identified, and the observed carbapenem resistance was likely mediated by overexpression of the detected extended-spectrum-\u03b2-lactamase (ESBL) genes associated with low membrane permeability as few carbapenemase genes were detected with just blaOXA-48 in three isolates. Colistin resistance was mediated either by non-synonymous mutations in the MgrB regulator, PmrA, PmrB, and PhoQ proteins or the presence of the MCR-1 protein. Here, gSNP analysis also revealed the existence of bacterial clones and cases of isolate transmissions between patients. The five analyzed P. aeruginosa isolates were highly resistant to all tested antibiotics, including carbapenems mediated by loss or truncated OprD porin, and colistin resistance was associated with mutations in the genes encoding the PmrA, PmrB, or PhoQ proteins. Conclusion: We demonstrate here the usefulness of whole-genome sequencing to exhaustively investigate the dissemination of MDR isolates at the sub-clone level. Thus, we suggest implementing such an approach to monitor the emergence and spread of new clones or sub-clones, which classical molecular analyses cannot detect. Moreover, we recommend increasing the surveillance of the endemic and problematic colistin resistance mcr-1 gene to avoid extensive dissemination.<\/jats:p>","DOI":"10.3390\/antibiotics11111597","type":"journal-article","created":{"date-parts":[[2022,11,14]],"date-time":"2022-11-14T02:32:01Z","timestamp":1668393121000},"page":"1597","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Genomic Characterization of Colistin-Resistant Isolates from the King Fahad Medical City, Kingdom of Saudi Arabia"],"prefix":"10.3390","volume":"11","author":[{"given":"Liliane","family":"Okdah","sequence":"first","affiliation":[{"name":"King Abdullah International Medical Research Center, National Guard Health Affairs, Riyadh 1126, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammed Saeed","family":"AlDosary","sequence":"additional","affiliation":[{"name":"Pathology and Clinical Laboratory Medicine Administration, King Fahad Medical City, Riyadh 11525, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abeer","family":"AlMazyed","sequence":"additional","affiliation":[{"name":"Pathology and Clinical Laboratory Medicine Administration, King Fahad Medical City, Riyadh 11525, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hussain Mushabbab","family":"Alkhurayb","sequence":"additional","affiliation":[{"name":"Pathology and Clinical Laboratory Medicine Administration, King Fahad Medical City, Riyadh 11525, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meshari","family":"Almossallam","sequence":"additional","affiliation":[{"name":"Pathology and Clinical Laboratory Medicine Administration, King Fahad Medical City, Riyadh 11525, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yousef sultan","family":"Al Obaisi","sequence":"additional","affiliation":[{"name":"Pathology and Clinical Laboratory Medicine Administration, King Fahad Medical City, Riyadh 11525, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammed Ali","family":"Marie","sequence":"additional","affiliation":[{"name":"Clinical Laboratory Sciences Department, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0381-9524","authenticated-orcid":false,"given":"Tamir","family":"Abdelrahman","sequence":"additional","affiliation":[{"name":"Laboratoire National de Sant\u00e9 (LNS), F3XP+Q4 Dudelange, Luxembourg"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6466-2324","authenticated-orcid":false,"given":"Seydina M.","family":"Diene","sequence":"additional","affiliation":[{"name":"MEPHI, IRD, APHM, IHU-Mediterranee Infection, Facult\u00e9 de Pharmacie, Aix-Marseille University, 13005 Marseille, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1177\/003335491412900402","article-title":"Antibiotic Resistance: A Public Health Crisis","volume":"129","author":"Lushniak","year":"2014","journal-title":"Public Health Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5873","DOI":"10.1128\/AAC.01019-15","article-title":"Carbapenemase-Producing Klebsiella Pneumoniae, a Key Pathogen Set for Global Nosocomial Dominance","volume":"59","author":"Pitout","year":"2015","journal-title":"Antimicrob. 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