{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,28]],"date-time":"2026-07-28T02:54:18Z","timestamp":1785207258323,"version":"3.55.0"},"reference-count":26,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,5,26]],"date-time":"2023-05-26T00:00:00Z","timestamp":1685059200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Internal Grant of College of Medicine"},{"name":"Health Sciences, Sultan Qaboos University, Muscat, Oman"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Background: The diminishing antimicrobial options for the treatment of XDR and PDR Acinetobacter baumannii is an increasing concern. In this study, we assessed the in vitro synergy of the fosfomycin (FOS) with meropenem (MEM), amikacin (AK), tigecycline (TGC), and colistin (CL) in whole genome sequenced isolates. Methods: Non-replicate whole genome sequenced (illumina next-generation sequencing platform, Clevergene, India), A. baumanii (7 XDR, 1PDR) were subjected to in vitro synergy testing by checkerboard (CB) and time kill assay (TKA) after MIC determination, with glucose-6-phosphate being incorporated in all runs. FOS was used as a cornerstone drug in four combinations and colistin in one. ResFinder, MLST, PlasmidFinder, and CSIPhylogeny tools were used. Results: Mortality occurred in three patients. Diverse MLST were observed, ST-1962 (3 isolates) and one each of ST2062, ST2063, ST1816, ST1806, ST234. FOS MICs ranged from 32 to 128 mg\/L, MEM MIC: 16\u201364 mg\/L, TGC MIC: \u22642\u2013\u22644 mg\/L and AK MIC: &gt;512 mg\/L. CL: MIC range, 0.25\u2013\u22642 mg\/L, PDR MIC &gt; 16 mg\/L. Synergy results by CB: FOS-MEM: synergy in \u215e (90%) isolates. Synergy lowered MEM MICs to susceptibility breakpoints in 6\/8 cases. CL-MEM: Excellent synergy (3\/3) isolates. FOS-AK: Indifference in \u215e, antagonism \u215b (AK-susceptible isolate). FOS-TGC: Partial synergy (PS) in 8\/8 (TGC MIC dropped to \u22640.25 mg\/L in 3\/8). In the PDR isolate, synergy was seen in FOS-MEM, CL-MEM, PS in FOS-CL, FOS-TGC, indifference in FOS-AK. TKA: Excellent synergy was observed with FOS-MEM from 4 h, while FOS-AK and FOS-TGC demonstrated synergy at 24 h. Synergy was achieved despite presence of widespread resistance markers against aminoglycosides (AacAad, AadA, AadB, Aph3\u2033Ia, ArmA, Arr, StrA, StrB), beta-lactams (ADC, BlaA1, BlaA2, Zn-dependent_hydrolase, OXA-23, OXA-51, PER-1,TEM-1D, CARB-5, Mbl), sulphonamides (SulII, SulI), phenicols (CatBx, CmlA), macrolides (MphE, MsrE) and tetracycline (TetB) were widespread. Carbapenemase, CARB-5 was present in one isolate. Beta-lactamase genes OXA-23, OXA-51, BlaA2, Zn-dependent_hydrolase, ADC, Mbl and macrolide resistance genes MphE, MsrE were present in all 8 isolates. Conclusions: FOS-MEM and CL-MEM are promising combinations against A. baumannii. Synergy of FOS-MEM in intrinsically resistant A. baumannii shows that this antibiotic combination might be useful in treating such XDR and PDR pathogens.<\/jats:p>","DOI":"10.3390\/microorganisms11061409","type":"journal-article","created":{"date-parts":[[2023,5,27]],"date-time":"2023-05-27T16:10:53Z","timestamp":1685203853000},"page":"1409","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Exploring Synergistic Combinations in Extended and Pan-Drug Resistant (XDR and PDR) Whole Genome Sequenced Acinetobacter baumannii"],"prefix":"10.3390","volume":"11","author":[{"given":"Munawr AL","family":"Quraini","sequence":"first","affiliation":[{"name":"Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zaaema AL","family":"Jabri","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4594-852X","authenticated-orcid":false,"given":"Hiba","family":"Sami","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Jawahar Lal Nehru Medical College, AMU, Aligarh 202001, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8456-5874","authenticated-orcid":false,"given":"Jaspreet","family":"Mahindroo","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1198-6138","authenticated-orcid":false,"given":"Neelam","family":"Taneja","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zakariya AL","family":"Muharrmi","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ibrahim AL","family":"Busaidi","sequence":"additional","affiliation":[{"name":"Infectious Diseases Unit, Sultan Qaboos University Hospital, Muscat 123, Oman"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meher","family":"Rizvi","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1111\/2049-632X.12125","article-title":"Acinetobacter baumannii: Evolution of a global pathogen","volume":"71","author":"Antunes","year":"2014","journal-title":"Pathog. 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