title: Emergence of Carbapenem-Resistant Klebsiella pneumoniae: Progressive Spread and Four-Year Period of Observation in a Cardiac Surgery Division.
abstract: Frequent use of carbapenems has contributed to the increase to K. pneumoniae strains resistant to this class of antibiotics (CRKP), causing a problem in the clinical treatment of patients. This investigation reports the epidemiology, genetic diversity, and clinical implication of the resistance to drugs mediated by CRKP in our hospital. A total of 280 K. pneumoniae strains were collected; in particular 98/280 (35%) were CRKP. Sequencing analysis of CRKP isolated strains showed that 9/98 of MBL-producing strains carried the bla VIM-1 gene and 89/98 of the isolates were positive for bla KPC-2. Antimicrobial susceptibility tests revealed a complete resistance to third-generation cephalosporins and a moderate resistance to tigecycline, gentamicin, and fluoroquinolones with percentages of resistance of 61%, 64%, and 98%, respectively. A resistance of 31% was shown towards trimethoprim-sulfamethoxazole. Colistin was the most active agent against CRKP with 99% of susceptibility. Clonality was evaluated by PFGE and MLST: MLST showed the same clonal type, ST258, while PFGE analysis indicated the presence of a major clone, namely, pulsotype A. This finding indicates that the prevalent resistant isolates were genetically related, suggesting that the spread of these genes could be due to clonal dissemination as well as to genetic exchange between different clones.
authors.affiliation: Research Laboratories-Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy.
authors.forename: Fortunata
authors.identifier: 0000-0002-9472-8873
authors.initials: F
authors.lastname: Lombardi
authors.affiliation: Clinical Microbiology Laboratory, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Gaia
authors.affiliation: Research Laboratories-Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy.
authors.forename: Rea
authors.initials: R
authors.lastname: Valaperta
authors.affiliation: Clinical Microbiology Laboratory, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Cornetta
authors.affiliation: Clinical Microbiology Laboratory, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Milvana Rosa
authors.initials: MR
authors.lastname: Tejada
authors.affiliation: Research Laboratories-Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy.
authors.forename: Luca
authors.identifier: 0000-0002-8047-5545
authors.initials: L
authors.lastname: Di Girolamo
authors.affiliation: Clinical Microbiology Laboratory, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Moroni
authors.affiliation: Clinical Microbiology Laboratory, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Ramundo
authors.affiliation: Service Lab Fleming Research, Milan, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Colombo
authors.affiliation: Service Lab Fleming Research, Milan, Italy.
authors.forename: Massimiliano
authors.identifier: 0000-0002-0522-3962
authors.initials: M
authors.lastname: Valisi
authors.affiliation: Research Laboratories-Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy ; Clinical Microbiology Laboratory, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Elena
authors.identifier: 0000-0001-6311-7618
authors.initials: E
authors.lastname: Costa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015780:Carbapenems / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003091:Colistin / Q000008:administration & dosage; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005260:Female; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000235:genetics* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D008297:Male; D008875:Middle Aged; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D015780:Carbapenems; C417264:VIM-1 metallo-beta-lactamase; D001618:beta-Lactamases; C547585:beta-lactamase KPC-2, Klebsiella pneumoniae; D003091:Colistin