Analysis of Antimicrobial Resistance and Infection Characteristics of Myroides odoratimimus Harboring the blaMOC-1 Metallo-β-Lactamase Gene

Rong Ding, Guiping Xia, Huacheng TongClinical Laboratory, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Huacheng Tong, Email [email protected]: To investigate the drug resistance genotype and phenotypic characteristics of a clinical isolate of Myroides odoratimimus producing metallo-β-lactamase, so as to provide reference for the diagnosis and treatment of similar severe infections in critical care settings. A Gram-negative bacillus isolated from blood cultures of an elderly patient with severe bloodstream infection was identified using the Vitek 2 Compact system combined with 16S rRNA gene sequencing. Antimicrobial susceptibility testing was performed using the broth microdilution method to determine minimum inhibitory concentrations (MICs). Metallo-β-lactamase phenotype was identified by the modified carbapenem inactivation method (mCIM) combined with the EDTA-modified carbapenem inactivation method (eCIM). The isolate was identified as Myroides odoratimimus. Both mCIM and eCIM tests were positive, confirming the production of metallo-β-lactamase. Whole-genome sequencing and database comparison revealed the presence of the blaMOC-1 gene in this strain, and PCR amplification followed by sequencing of electrophoretic bands yielded a 629-bp blaMOC-1 sequence. Antimicrobial susceptibility testing showed that the isolate exhibited broad-spectrum resistance and was only susceptible to minocycline, doxycycline, levofloxacin, and cefepime. The patient presented with severe septic shock, showed no response to empirical therapy, developed multiple organ injury, and exhibited abnormally elevated biomarkers of inflammation, metabolism, and cardiovascular function. The findings of this study suggest that the blaMOC-1 gene is carried by this strain and is associated with its broad-spectrum antimicrobial resistance characteristics.Keywords: Myroides odoratimimus, metallo-β-lactamase, blaMOC-1 gene, septic shock, drug resistance