Resistome analysis of multidrug-resistant Klebsiella pneumoniae L-15 harboring blaCTX-M-15 isolated from a diabetic foot ulcer using a low-volume portable broth medium

Diabetes mellitus is one of the most prevalent non-communicable diseases in Indonesia. Diabetic foot ulcer (DFU) infections are among the most severe complications, often leading to bacteremia and mortality. This study aimed to apply a low-volume broth medium supplemented with antibiotics for screening multidrug-resistant (MDR) bacteria. We used modified low-volume medium for bacterial isolation from diabetic foot ulcers. Bacterial identification and antimicrobial susceptibility testing were performed, followed by whole-genome sequencing for resistome analysis. Out of 15 DFU samples, 5 yielded bacteria resistant to amoxicillin and ceftriaxone. Molecular identification using the partial 16S rRNA gene classified these isolates as Klebsiella pneumoniae , Pseudomonas aeruginosa , Proteus mirabilis , and Providencia sp. Notably, 5 out of 7 isolates were categorized as MDR due to their resistance to more than three antimicrobial classes. Furthermore, K. pneumoniae L15 exhibited high-level resistance to ceftriaxone with a minimum inhibitory concentration (MIC) of ≥128 µg mL −1 . Resistome analysis of K. pneumoniae L15 revealed the presence of aph , bla CTX-M-15 , catA2 , fosA , qnrS1 , sul2 , and tetA . Interestingly, bla CTX-M-15 was flanked by mobile genetic elements (MGEs), specifically Tn3 upstream and IS1380 downstream. The bla CTX-M-15 gene structure identified in this study has also been reported in various other Gram-negative bacteria. Detection and analysis of MDR bacterial pathogens in DFU is important for patients care and to decrease spread of MDR pathogens. The bla CTX-M-15 gene in this K. pneumoniae isolate is putatively capable of disseminating to other bacteria via MGEs. Multilocus sequence typing (MLST) determination showed K. pneumoniae L15 in this study belongs to ST14464.