Piotr Majewski1, Piotr Wieczorek2, Izabela Łapuć3, Dominika Ojdana2, Anna Sieńko2, Paweł Sacha2, Janusz Kłoczko3, Elżbieta Tryniszewska2. 1. Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland. Electronic address: piotr.majewski@umb.edu.pl. 2. Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Bialystok, Poland. 3. Department of Hematology, Medical University Hospital of Bialystok, Bialystok, Poland.
Abstract
OBJECTIVES: The growing incidence of multidrug-resistant (MDR) bacteria is an emerging challenge in modern medicine. The utility of carbapenems, which are considered 'last-line' agents, is being diminished by the growing incidence of various resistance mechanisms in Gram-negative bacteria. A molecular investigation was performed of an MDR carbapenem-resistant Citrobacter freundii of sequence type 8 (ST8) isolated from a hematology patient with acute myeloid leukemia. METHODS: Multilocus sequence typing and analysis of the nucleotide sequence of the class I integron were performed using PCR and Sanger sequencing. Transformation of the resistance plasmid isolated following the alkaline lysis method was performed using chemically competent E. coli TOP10. RESULTS: Molecular analysis of the carbapenem-resistant C. freundii revealed the presence of the VIM-4 isoenzyme located on the ∼55-kb transferable resistance plasmid. Interestingly, the blaVIM-4 gene was inserted into an unusual gene cassette containing a 169-bp direct repeat of the 3' segment of the blaVIM-4 gene. CONCLUSIONS: All unusual gene cassettes containing VIM-DR (direct repeat) described thus far have been harbored by non-fermenters, i.e., Acinetobacter and Pseudomonas, underscoring the importance of resistance determinant mobility, which may go even beyond genus, family, and order boundaries. Great efforts need to be taken to explore pathways of resistance to 'last-resort' antimicrobials, especially among clinically relevant pathogens.
OBJECTIVES: The growing incidence of multidrug-resistant (MDR) bacteria is an emerging challenge in modern medicine. The utility of carbapenems, which are considered 'last-line' agents, is being diminished by the growing incidence of various resistance mechanisms in Gram-negative bacteria. A molecular investigation was performed of an MDR carbapenem-resistant Citrobacter freundii of sequence type 8 (ST8) isolated from a hematology patient with acute myeloid leukemia. METHODS: Multilocus sequence typing and analysis of the nucleotide sequence of the class I integron were performed using PCR and Sanger sequencing. Transformation of the resistance plasmid isolated following the alkaline lysis method was performed using chemically competent E. coli TOP10. RESULTS: Molecular analysis of the carbapenem-resistant C. freundii revealed the presence of the VIM-4 isoenzyme located on the ∼55-kb transferable resistance plasmid. Interestingly, the blaVIM-4 gene was inserted into an unusual gene cassette containing a 169-bp direct repeat of the 3' segment of the blaVIM-4 gene. CONCLUSIONS: All unusual gene cassettes containing VIM-DR (direct repeat) described thus far have been harbored by non-fermenters, i.e., Acinetobacter and Pseudomonas, underscoring the importance of resistance determinant mobility, which may go even beyond genus, family, and order boundaries. Great efforts need to be taken to explore pathways of resistance to 'last-resort' antimicrobials, especially among clinically relevant pathogens.
Authors: José Ramos-Vivas; Itziar Chapartegui-González; Marta Fernández-Martínez; Claudia González-Rico; John Barrett; Jesús Fortún; Rosa Escudero; Francesc Marco; Laura Linares; Javier Nieto; Maitane Aranzamendi; Patricia Muñoz; Maricela Valerio; Jose María Aguado; Fernando Chaves; Irene Gracia-Ahufinger; Aurora Paez-Vega; Luis Martínez-Martínez; María Carmen Fariñas Journal: Front Cell Infect Microbiol Date: 2020-09-16 Impact factor: 5.293