Biology subjects

Mantzouratou, A.

Publications and source records attributed to Mantzouratou, A..

2 recordsLinked to original sources

bioRxiv2022

Bioinformatic analyses of plasmid resistome changes in pOXA-48

Infections caused by carbapenem resistant Enterobacteriales (CPE) represent a significant threat in clinical settings. blaOXA-48 is one of the most frequent carbapenemase genes among Enterobacteriales. The blaOXA-48 is typically encoded on the prototypical IncL conjugative pOXA-48 plasmid. The pOXA-48 plasmid encodes only the blaOXA-48 resistance gene. However, aminoglycoside and extended spectrum {beta}-lactamase (ESBL) resistance genes have also been detected on the same pOXA-48 plasmid backbone. These pOXA-48 plasmids encoding additional antimicrobial resistance (AMR) genes have been associated with both poor patient outcome and increased minimal inhibitory concentrations (MICs) to antibiotics including broad-spectrum cephalosporins. The blaOXA-48 gene was sourced from the pOXA-48 reference plasmid and set as a query using the BLASTn tool. Non-duplicate blaOXA-48 containing plasmids were downloaded, incompatibility typed and annotated for resistance genes using ResFinder 4.0. Bioinformatic analyses identified three distinct variants of the pOXA-48 plasmid encoding 4, 5, and 6 antimicrobial resistance genes. All plasmids encoded the ESBL blaCTX-M-14b, blaOXA-48 and either 2, 3 or 4 aminoglycoside resistance genes, in addition to conjugative transfer machinery. Plasmid variants 1 and 3 encoded aminoglycoside genes bracketed between IS26 and ISEc63 insertion elements, forming a potential transposon. The potential transposon structure had resemblance to the Tn5393 transposon (accession: M96392), including both aph(3)-Ib, aph(6)-Id genes, and a Tn3 resolvase. The IS element ISEcp1 lies upstream of blaCTX-M-14b. All three plasmid variants appear related. Notably, all pOXA-48 plasmid variants were identified in multiple countries. In particular, variant 1 including 6 AMR genes was detected in 7 unique countries. Plasmids encoding additional AMR genes were associated with clinical/surveillance samples suggesting antibiotic pressure in clinical settings may promote changes in the resistome of pOXA-48. Acquisition of pOXA-48 resistant plasmids carrying additional AMR genes beyond blaOXA-48 can change the resistome of susceptible isolates in a single-step, rendering previously susceptible strains refractory to almost all available treatment options.

microbiology↗

bioRxiv2021

Plasmids as donors of Insertion Sequence elements mediating colistin resistance in Klebsiella pneumoniae

Colistin is a last resort antibiotic for the treatment of carbapenemase producing Klebsiella pneumoniae (CRKP). In line with rising colistin use worldwide, colistin resistant Klebsiella pneumoniae (K. pneumoniae) isolates have emerged. The disruption of mgrB by insertion sequences (ISs) has been widely reported worldwide representing a mechanism mediating colistin resistance. Evidence suggests plasmids encode mobilizable IS elements which preferentially integrate into the mgrB gene in K. pneumoniae causing gene inactivation and colistin resistance. Recognised IS elements targeting mgrB include ISL3 (ISKpn25), IS5 (ISKpn26), ISKpn14 and IS903B-like elements. K. pneumoniae represents the single largest species carrying plasmids encoding these IS elements. For IS presence among species, 1000 BLASTn hits were downloaded and filtered for plasmids. Additionally, the top 120 BLASTn non-duplicate circularised plasmid contig hits for each IS element were typed for incompatibility (Inc) group and carbapenemase gene presence. IS903B was found in 28 unique Inc groups, while ISKpn25 was largely carried by IncFIB(pQil) plasmids. ISKpn26 and ISKpn14 were most often found associated with IncFII(pHN7A8) plasmids. Of the 34 unique countries which contained any of the IS elements, ISKpn25 was identified from 26. ISKpn26, ISKpn14, and IS903B insertion sequences were identified from 89.3%, 44.9% and 23.9% plasmid samples from China. Plasmids carrying ISKpn25, ISKpn14, and ISKpn26 IS elements are 12.18, 27.0, and 44.43 times more likely to carry carbapenemase genes relative to plasmids carrying the IS element IS903B. Moreover, plasmids carrying ISKpn26, ISKpn25, and ISKpn14 were 6.10, 28.82, and 31.47 times more likely to be sourced from a clinical environmental setting than the environment relative to IS903B IS harboring plasmid. ISKpn25 present on IncFIB(pQil) sourced from clinical settings is established across multiple countries, while ISKpn26, ISKpn14, and IS903B appear most often in China. High carbapenemase presence in tandem with IS elements may help promote an extensively drug resistant profile in K. pneumoniae limiting already narrow therapeutic treatment options.

microbiology↗