The following is a summary of “Comparative genomic analysis of strong biofilm-forming Klebsiella pneumoniae isolates uncovers novel ISEcp1-mediated chromosomal integration of a full plasmid-like sequence,” published in the December 2023 issue of Infectious Disease by Hamed et al.

Researchers conducted a retrospective analysis of Klebsiella pneumoniae’s genome, aiming to decipher the genetic forces driving its biofilm formation, a critical aspect of its resilience.

They screened clinical isolates for biofilm formation using the crystal violet assay. Antimicrobial resistance (AMR) profiles were evaluated through disk diffusion and broth microdilution tests. PCR explored correlations between biofilm formation and virulence and resistance genes. Draft genomes of three strongly biofilm-forming isolates were generated using Illumina sequencing.

The results showed a significant association of the siderophore-coding gene iutA with enhanced biofilm formation. ST1399-KL43-O1/O2v1 and ST11-KL15-O4 were classified as multidrug-resistant strain K21 and extensively drug-resistant strain K237, respectively. ST1999-KL38-O12 was identified as K57. Correlated with CRISPR/Cas distribution, K21, and K237 exhibited more plasmid replicons and prophage sequences than K57. Acquired AMR genes (bla _OXA-48, rmtF, aac(6′)-Ib, and qnrB) and (bla _NDM-1, bla _CTX-M, aph(3′)-VI, qnrS, and aac(6′)-Ib-cr) were found in K237 and K21, respectively. The latter displayed a novel ISEcp1-mediated chromosomal integration of replicon type IncM1 plasmid-like structure containing bla _CTX-M-14 and aph(3′)-VI, disrupting rcsC. K21 harbored plasmid-mediated heavy metal resistance genes merACDEPRT and arsABCDR, along with exclusively carrying the acquired virulence genes mrkABCDF and the hypervirulence-associated genes iucABCD-iutA and rmpA/A2. Pangenome analysis revealed NTUH-K2044 accessory genes most frequently shared with K21.

They concluded that despite lower insect virulence, multidrug-resistant K21, harboring unique genetic traits, poses a severe threat, demanding regional attention.

Source: tandfonline.com/doi/full/10.1080/23744235.2023.2272624