1
|
Carrasco LDDM, Dabul ANG, Boralli CMDS, Righetto GM, Carvalho ISE, Dornelas JV, Martins da Mata CPS, de Araújo CA, Leite EMM, Lincopan N, Camargo ILBDC. Polymyxin Resistance Among XDR ST1 Carbapenem-Resistant Acinetobacter baumannii Clone Expanding in a Teaching Hospital. Front Microbiol 2021; 12:622704. [PMID: 33897637 PMCID: PMC8063854 DOI: 10.3389/fmicb.2021.622704] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen primarily associated with multidrug-resistant nosocomial infections, for which polymyxins are the last-resort antibiotics. This study investigated carbapenem-resistant A. baumannii strains exhibiting an extensively drug-resistant (XDR) phenotype, including four isolates considered locally pan drug-resistant (LPDR), isolated from inpatients during an outbreak at a teaching hospital in Brazil. ApaI DNA macrorestriction followed by PFGE clustered the strains in three pulsotypes, named A to C, among carbapenem-resistant A. baumannii strains. Pulsotypes A and B clustered six polymyxin-resistant A. baumannii strains. MLST analysis of representative strains of pulsotypes A, B, and C showed that they belong, respectively, to sequence types ST1 (clonal complex, CC1), ST79 (CC79), and ST903. Genomic analysis of international clones ST1 and ST79 representative strains predicted a wide resistome for β-lactams, aminoglycosides, fluoroquinolones, and trimethoprim-sulfamethoxazole, with blaOXA–23 and blaOXA–72 genes encoding carbapenem resistance. Amino acid substitutions in PmrB (Thr232Ile or Pro170Leu) and PmrC (Arg125His) were responsible for polymyxin resistance. Although colistin MICs were all high (MIC ≥ 128 mg/L), polymyxin B MICs varied; strains with Pro170Leu substitution in PmrB had MICs > 128 mg/L, while those with Thr232Ile had lower MICs (16–64 mg/L), irrespective of the clone. Although the first identified polymyxin-resistant A. baumannii strain belonged to ST79, the ST1 strains were endemic and caused the outbreak most likely due to polymyxin B use. The genome comparison of two ST1 strains from the same patient, but one susceptible and the other resistant to polymyxin, revealed mutations in 28 ORFs in addition to pmrBC. The ORF codifying an acyl-CoA dehydrogenase has gained attention due to its fatty acid breakdown and membrane fluidity involvement. However, the role of these mutations in the polymyxin resistance mechanism remains unknown. To prevent the dissemination of XDR bacteria, the hospital infection control committee implemented the patient bathing practice with a 2% chlorhexidine solution, a higher concentration than all A. baumannii chlorhexidine MICs. In conclusion, we showed the emergence of polymyxin resistance due to mutations in the chromosome of the carbapenem-resistant A. baumannii ST1, a high-risk global clone spreading in this hospital.
Collapse
Affiliation(s)
- Letícia Dias de Melo Carrasco
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| | - Andrei Nicoli Gebieluca Dabul
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| | - Camila Maria Dos Santos Boralli
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| | - Gabriela Marinho Righetto
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| | - Iago Silva E Carvalho
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| | - Janaína Valerini Dornelas
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| | | | | | | | - Nilton Lincopan
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ilana Lopes Baratella da Cunha Camargo
- Laboratory of Molecular Epidemiology and Microbiology, Department of Physics and Interdisciplinary Science, São Carlos Institute of Physics, University of São Paulo, São Paulo, Brazil
| |
Collapse
|
2
|
Camargo CH, Cunha MPV, de Barcellos TAF, Bueno MS, Bertani AMDJ, dos Santos CA, Nagamori FO, Takagi EH, Chimara E, de Carvalho E, Tiba-Casas MR. Genomic and phenotypic characterisation of antimicrobial resistance in carbapenem-resistant Acinetobacter baumannii hyperendemic clones CC1, CC15, CC79 and CC25. Int J Antimicrob Agents 2020; 56:106195. [DOI: 10.1016/j.ijantimicag.2020.106195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 07/29/2020] [Accepted: 10/04/2020] [Indexed: 12/17/2022]
|
3
|
Tavares LCB, de Vasconcellos FM, de Sousa WV, Rocchetti TT, Mondelli AL, Ferreira AM, Montelli AC, Sadatsune T, Tiba-Casas MR, Camargo CH. Emergence and Persistence of High-Risk Clones Among MDR and XDR A. baumannii at a Brazilian Teaching Hospital. Front Microbiol 2019; 9:2898. [PMID: 30662431 PMCID: PMC6328482 DOI: 10.3389/fmicb.2018.02898] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 11/12/2018] [Indexed: 01/04/2023] Open
Abstract
Dissemination of carbapenem-resistant Acinetobacter baumannii is currently one of the priority themes discussed around the world, including in Brazil, where this pathogen is considered endemic. A total of 107 carbapenem-resistant A. baumannii (CRAB) isolates were collected from patients with bacteraemia attended at a teaching hospital in Brazil from 2008 to 2014. From these samples, 104 (97.2%) carried blaOXA−23−like, all of them associated with ISAba1 The blaOXA−231 (1.9%) and blaOXA−72 (0.9%) genes were also detected in low frequencies. All isolates were susceptible to minocycline, and 38.3% of isolates presented intermediate susceptibility to tigecycline (MIC = 4 μg/ml). Molecular typing assessed by multi-locus sequence typing demonstrated that the strains were mainly associated with clonal complexes CC79 (47.4%), followed by CC1 (16.9%), and CC317 (18.6%), belonging to different pulsotypes and in different prevalences over the years. Changes in the clones' prevalence reinforce the need of identifying and controlling CRAB in hospital settings to preserve the already scarce therapeutic options available.
Collapse
Affiliation(s)
- Laís Calissi Brisolla Tavares
- Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, Brazil
| | | | | | | | | | | | | | | | | | - Carlos Henrique Camargo
- Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.,Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, Brazil
| |
Collapse
|