title: Predominance of IncL/M and IncF plasmid types among CTX-M-ESBL-producing Escherichia coli and Klebsiella pneumoniae in Bulgarian hospitals.
abstract: Our objective was to investigate the plasmid replicon-types involved in spread of ESBLs among Bulgarian Klebsiella pneumoniae and Escherichia coli. Sixty-three isolates, with transferable beta-lactam resistance determinants, collected between 2007 and 2009 in six medical institutions, were analysed with respect to their antimicrobial susceptibility, ESBL-, RAPD-, and plasmid replicon-type. Phylogenetic typing and screening for the O25b-ST131 lineage were carried out for E. coli. The predominant ESBLs were CTX-M-15 (81%) among E. coli and CTX-M-3 (58%) among K. pneumoniae. Other sporadically found ESBLs were SHV-12 and TEM-139, and for the first time in Bulgaria, CTX-M-1 and CTX-M-14. Replicon typing revealed that plasmids carrying blaCTX-M-3 exclusively belonged to IncL/M-type, while blaCTX-M-15 was predominantly (94%) associated with IncF-type plasmids. Among E. coli, 59% of the isolates were clonally related. Isolates of that cluster produced CTX-M-15, belonged to the O25b-ST131 lineage, predominantly harboured plasmids with the FIA replicon, and were found in five centres. Among CTX-M-3-producing K. pneumoniae, two prevailing RAPD-types were found, one remained restricted to one centre and the second was found in three centres. The incompatibility groups IncN and IncA/C linked with blaSHV-12 respectively blaTEM-139 were found only once. To the best of our knowledge, this is the first detailed investigation of plasmids carrying ESBL genes among Bulgarian isolates demonstrating wide distribution of conjugative IncF plasmids among CTX-M-15-producing E. coli and IncL/M plasmids among CTX-M-3 positive K. pneumoniae isolates.
authors.affiliation: Department of Medical Microbiology, Medical University, Sofia, Bulgaria.
authors.forename: Rumyana
authors.initials: R
authors.lastname: Markovska
authors.forename: Ines
authors.initials: I
authors.lastname: Schneider
authors.forename: Dobrinka
authors.initials: D
authors.lastname: Ivanova
authors.forename: Ivan
authors.initials: I
authors.lastname: Mitov
authors.forename: Adolf
authors.initials: A
authors.lastname: Bauernfeind
mesh_terms: D001483:Base Sequence; D002031:Bulgaria; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy; D006761:Hospitals; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058889:Molecular Typing; D010957:Plasmids / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics
chemical_list: C473109:beta-lactamase CTX-M-15; C417271:beta-lactamase CTX-M-3; C107198:beta-lactamase SHV-12; C055184:beta-lactamase TEM-3; D001618:beta-Lactamases
keywords: CTX-M; Enterobacteriaceae; IncF; IncL/M; replicon typing