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Jayol A, Poirel L, André C, Dubois V, Nordmann P. Detection of colistin-resistant Gram-negative rods by using the SuperPolymyxin medium. Diagn Microbiol Infect Dis 2018; 92:95-101. [DOI: 10.1016/j.diagmicrobio.2018.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 10/16/2022]
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102
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Uechi K, Tada T, Shimada K, Nakasone I, Kirikae T, Fujita J. Emergence of a carbapenem-resistant and colistin-heteroresistant Enterobacter cloacae clinical isolate in Japan. J Infect Chemother 2018; 25:285-288. [PMID: 30279112 DOI: 10.1016/j.jiac.2018.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 08/08/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
Abstract
A carbapenem-resistant and colistin-heteroresistant clinical isolate of Enterobacter cloacae was obtained from an inpatient in Okinawa, Japan. The minimum inhibitory concentrations of both imipenem and meropenem were 32 μg/mL. The isolate showed heteroresistance to colistin using the Etest method and resistance to colistin using the broth microdilution method. It had a disrupted ompC and a mutation in the promoter region of blaACT-2, but did not harbor any genes encoding carbapenemase. The disruption of ompC and the mutation in blaACT-2 was associated with the carbapenem resistance of this isolate. This isolate also had mutations in pmrAB and phoPQ encoding two-component regulatory systems, which may be associated with colistin heteroresistance.
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Affiliation(s)
- Kohei Uechi
- Department of Infectious Diseases, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan; Division of Clinical Laboratory and Blood Transfusion, University Hospital of the Ryukyus, Okinawa, Japan
| | - Tatsuya Tada
- Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan; Department of Infectious Disease, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kayo Shimada
- Department of Infectious Disease, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Isamu Nakasone
- Control and Prevention of Infectious Disease, University Hospital of the Ryukyus, Okinawa, Japan
| | - Teruo Kirikae
- Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan; Department of Infectious Disease, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
| | - Jiro Fujita
- Department of Infectious Diseases, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
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103
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Barragán-Prada H, Ruiz-Hueso P, Tedim AP, González-Candelas F, Galán JC, Cantón R, Morosini MI. Emergence and dissemination of colistin-resistant Klebsiella pneumoniae isolates expressing OXA-48 plus CTX-M-15 in patients not previously treated with colistin in a Spanish university hospital. Diagn Microbiol Infect Dis 2018; 93:147-153. [PMID: 30266401 DOI: 10.1016/j.diagmicrobio.2018.08.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 08/28/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022]
Abstract
Dissemination of multidrug-resistant Klebsiella pneumoniae in the hospital environment represents a primary target of resistance containment and stewardship programs. At present, polymyxins, mostly in combination, exemplify a last-resort alternative. Colistin-resistant K. pneumoniae isolates harboring OXA-48 plus CTX-M-15 (n = 21) with the simultaneous colistin-susceptible counterparts (n = 9) were recovered from 14 hospitalized patients (January 2014-January 2015) admitted in different wards. In most cases, patients had not previously received colistin. Genetic relatedness experiments demonstrated that 93% (28/30) of isolates belonged to the ST11 high-risk clone. Heteroresistance and the fitness cost of colistin resistance were addressed in susceptible and resistant isolates as well as in in vitro-obtained stable mutants, and results appeared to be strain dependent. Whole genome sequencing demonstrated molecular changes in pmrA, pmrB, and mgrB genes. Plasmid-mediated colistin resistance genes were not found. Colistin resistance in multidrug-resistant K. pneumoniae isolates should be continuously monitored to detect its potential emergence, even in patients not previously exposed to colistin.
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Affiliation(s)
- Hugo Barragán-Prada
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Paula Ruiz-Hueso
- Unidad Mixta "Infección y Salud Pública" FISABIO-Instituto de Biología Integrativa de Sistemas (I2SysBio), Universitat de València, Spain; CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana P Tedim
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
| | - Fernando González-Candelas
- Unidad Mixta "Infección y Salud Pública" FISABIO-Instituto de Biología Integrativa de Sistemas (I2SysBio), Universitat de València, Spain; CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Carlos Galán
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos los III, Madrid, Spain.
| | - María-Isabel Morosini
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos los III, Madrid, Spain
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104
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Kim SJ, Ko KS. Diverse genetic alterations responsible for post-exposure colistin resistance in populations of the same strain of Klebsiella pneumoniae. Int J Antimicrob Agents 2018; 52:425-429. [DOI: 10.1016/j.ijantimicag.2018.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 03/24/2018] [Accepted: 06/16/2018] [Indexed: 02/03/2023]
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105
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Uz Zaman T, Albladi M, Siddique MI, Aljohani SM, Balkhy HH. Insertion element mediated mgrB disruption and presence of ISKpn28 in colistin-resistant Klebsiella pneumoniae isolates from Saudi Arabia. Infect Drug Resist 2018; 11:1183-1187. [PMID: 30147346 PMCID: PMC6101004 DOI: 10.2147/idr.s161146] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background In Klebsiella pneumoniae, mgrB and components of pmrHFIJKLM operon play a major role in colistin resistance. Methods We analyzed 23 nonduplicating colistin-resistant K. pneumoniae isolates, collected during the years 2011–2015, for the possible mechanism underlying their nonsusceptibility to colistin. Isolates were tested for their minimum inhibitory concentrations and antibiotic resistance determinants and genotyped by multilocus sequence typing (MLST). The MLST genes, antibiotic-resistant genes, and the genes of two component system (TCS), including mgrB, PhoQ/PhoP, pmrA/B, and CrrAB, were investigated by PCR amplification and Sanger sequencing. Results All isolates were distributed in eight sequence types (STs) and showed mutations either in mgrB or PhoP genes. ISKpn14 was found in 10, ISKpn28 in four, and IS903 in three isolates. One isolate showed deletion of a single nucleotide in mgrB open reading frame causing premature stop codon. L26Q substitution in PhoP was found in five isolates. Conclusion The mutations in mgrB were mostly mediated by insertion elements (IS). ISKpn14 is the major IS while ISKpn28 is reported for the first time in mediating mgrB disruption. IS903, an IS5 family member, involved in mgrB disruption in three ST-152 NDM-1-positive isolates, was previously responsible for omp-36 disruption in our carbapenem-resistant K. pneumoniae and appears to contribute to transform the isolates into a pan-drug ones. Also, the abundance of insertion sites in mgrB indicates the plasticity of this gene. In our isolates, IS-mediated colistin resistance appears to be a later phenomenon than mutation in PhoP gene.
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Affiliation(s)
- Taher Uz Zaman
- Infectious Diseases Research Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia,
| | - Maha Albladi
- Infectious Diseases Research Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia,
| | | | - Sameera M Aljohani
- Microbiology Section, King Abdulaziz Medical City, Riyadh, Saudi Arabia.,Department of Microbiology, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Hanan H Balkhy
- Infectious Diseases Research Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia, .,Department of Infection Prevention and Control, King Abdulaziz Medical City, National Guards Health Affairs, Riyadh, Saudi Arabia
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106
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Colistin Does Not Potentiate Ceftazidime-Avibactam Killing of Carbapenem-Resistant Enterobacteriaceae In Vitro or Suppress Emergence of Ceftazidime-Avibactam Resistance. Antimicrob Agents Chemother 2018; 62:AAC.01018-18. [PMID: 29891598 DOI: 10.1128/aac.01018-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 06/04/2018] [Indexed: 11/20/2022] Open
Abstract
We tested ceftazidime-avibactam and colistin against 24 carbapenem-resistant Enterobacteriaceae (CRE) isolates by time-kill studies. Ceftazidime-avibactam at 0.25×, 1×, and 4× the MIC was bactericidal against 8%, 21%, and 88% of the isolates, respectively. Colistin (2 μg/ml) was bactericidal against 83% (12 h) and 42% (24 h) of the isolates. In combination, synergy and antagonism were identified against 13% and 46% of the isolates, respectively. The combination did not suppress ceftazidime-avibactam resistance. Colistin plus ceftazidime-avibactam did not provide a benefit over ceftazidime-avibactam against most CRE isolates.
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107
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Esposito EP, Cervoni M, Bernardo M, Crivaro V, Cuccurullo S, Imperi F, Zarrilli R. Molecular Epidemiology and Virulence Profiles of Colistin-Resistant Klebsiella pneumoniae Blood Isolates From the Hospital Agency "Ospedale dei Colli," Naples, Italy. Front Microbiol 2018; 9:1463. [PMID: 30061868 PMCID: PMC6054975 DOI: 10.3389/fmicb.2018.01463] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/12/2018] [Indexed: 11/13/2022] Open
Abstract
Resistance to colistin is increasingly reported in Klebsiella pneumoniae clinical isolates. The aim of this study was to analyze the molecular epidemiology and virulence profiles of 25 colistin-resistant K. pneumoniae blood isolates from the Hospital Agency “Ospedale dei Colli,” Naples, Italy, during 2015 and 2016. Colistin MIC values of isolates ranged from 4 to 256 mg/L. The inactivation of the mgrB gene, encoding a negative regulator of the PhoQ/PhoP signaling system, was the most frequent mechanism of colistin resistance found in 22 out of 25 isolates. Of these, 10 isolates assigned to ST512 and PFGE types A and A4 showed identical frameshift mutation and premature termination of mgrB gene; 4 isolates assigned to ST258 and PFGE types A1 showed non-sense, frameshift mutation, and premature termination; 3 and 1 isolates assigned to ST258 and PFGE A2 and ST512 and PFGE A3, respectively, had insertional inactivation of mgrB gene due to IS5-like mobile element; 2 isolates assigned to ST101 and 1 to ST392 had missense mutations in the mgrB gene, 1 isolate assigned to ST45 showed insertional inactivation of mgrB gene due to IS903-like mobile element. phoQ missense mutations were found in 2 isolates assigned to ST629 and ST101, respectively, which also showed a missense mutation in pmrA gene. The mcr-1-2-3-4 genes were not detected in any isolate. Colistin-resistant K. pneumoniae isolates showed variable virulence profiles in Galleria mellonella infection assays, with the infectivity of two isolates assigned to ST45 and ST629 being significantly higher than that of all other strains (P < 0.001). Interestingly, colistin MIC values proved to make a significant contribution at predicting lethal doses values (LD50 and LD90) of studied isolates in G. mellonella. Our data show that MgrB inactivation is a common mechanism of colistin resistance among K. pneumoniae in our clinical setting. The presence of identical mutations/insertions in isolates of the same ST and PFGE profile suggests the occurrence of clonal expansion and cross-transmission. Although virulence profiles differ among isolates irrespective of their genotypes, our results suggest that high colistin MIC could predict lower infectivity capability of the isolates.
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Affiliation(s)
- Eliana P Esposito
- Department of Public Health, University of Naples "Federico II,", Naples, Italy
| | - Matteo Cervoni
- Department of Biology and Biotechnology "Charles Darwin," Sapienza University of Rome, Rome, Italy.,Laboratory Affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Mariano Bernardo
- Azienda Ospedaliera di Rilievo Nazionale (AORN) dei Colli, V. Monaldi Hospital, Naples, Italy
| | - Valeria Crivaro
- Azienda Ospedaliera di Rilievo Nazionale (AORN) dei Colli, V. Monaldi Hospital, Naples, Italy
| | - Susanna Cuccurullo
- Azienda Ospedaliera di Rilievo Nazionale (AORN) dei Colli, V. Monaldi Hospital, Naples, Italy
| | - Francesco Imperi
- Department of Biology and Biotechnology "Charles Darwin," Sapienza University of Rome, Rome, Italy.,Laboratory Affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples "Federico II,", Naples, Italy.,Centro di Ingegneria Genetica (CEINGE) Biotecnologie Avanzate, Naples, Italy
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108
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Cain AK, Boinett CJ, Barquist L, Dordel J, Fookes M, Mayho M, Ellington MJ, Goulding D, Pickard D, Wick RR, Holt KE, Parkhill J, Thomson NR. Morphological, genomic and transcriptomic responses of Klebsiella pneumoniae to the last-line antibiotic colistin. Sci Rep 2018; 8:9868. [PMID: 29959380 PMCID: PMC6026146 DOI: 10.1038/s41598-018-28199-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 06/08/2018] [Indexed: 11/09/2022] Open
Abstract
Colistin remains one of the few antibiotics effective against multi-drug resistant (MDR) hospital pathogens, such as Klebsiella pneumoniae. Yet resistance to this last-line drug is rapidly increasing. Characterized mechanisms of colR in K. pneumoniae are largely due to chromosomal mutations in two-component regulators, although a plasmid-mediated colR mechanism has recently been uncovered. However, the effects of intrinsic colistin resistance are yet to be characterized on a whole-genome level. Here, we used a genomics-based approach to understand the mechanisms of adaptive colR acquisition in K. pneumoniae. In controlled directed-evolution experiments we observed two distinct paths to colistin resistance acquisition. Whole genome sequencing identified mutations in two colistin resistance genes: in the known colR regulator phoQ which became fixed in the population and resulted in a single amino acid change, and unstable minority variants in the recently described two-component sensor crrB. Through RNAseq and microscopy, we reveal the broad range of effects that colistin exposure has on the cell. This study is the first to use genomics to identify a population of minority variants with mutations in a colR gene in K. pneumoniae.
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Affiliation(s)
- Amy K Cain
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK. .,Chemistry and Biomolecular Sciences, Macquarie University, Sydney, Australia.
| | - Christine J Boinett
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK. .,Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Würzburg, D-97080, Germany
| | - Janina Dordel
- Department of Biology, Drexel University, Philadelphia, 19104, PA, USA
| | - Maria Fookes
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Matthew Mayho
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | | | - David Goulding
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Ryan R Wick
- Centre for Systems Genomics, The University of Melbourne, Melbourne, VIC, Australia
| | - Kathryn E Holt
- Centre for Systems Genomics, The University of Melbourne, Melbourne, VIC, Australia.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Nicholas R Thomson
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK. .,Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
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109
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Porreca AM, Sullivan KV, Gallagher JC. The Epidemiology, Evolution, and Treatment of KPC-Producing Organisms. Curr Infect Dis Rep 2018; 20:13. [PMID: 29730830 DOI: 10.1007/s11908-018-0617-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE OF REVIEW The purpose of this review is to investigate the evolution and epidemiology of Klebsiella pneumoniae carbapenemase (KPC)-producing organisms and the current and future treatment options for infections caused by KPC-producing isolates. RECENT FINDINGS The emergence of resistance in Enterobacteriaceae producing carbapenemases globally has increased the challenges in treating infections caused by these organisms. One of the prominent mechanisms of resistance is the production of KPC enzymes. Infections caused by organisms producing KPCs have limited treatment options and are associated with poor clinical outcomes. The rapid rise of KPC-producing organisms necessitated the use of drugs with pharmacokinetic and toxicity limitations, including polymyxins, tigecycline, fosfomycin, and aminoglycosides. The availability of new beta-lactamase inhibitor combinations that are effective against KPC-producing organisms represent an advance in safety and efficacy. Several agents are currently being studied that have activity against KPC-producing organisms and appear to represent promising additions to our armamentarium. KPC-producing organisms cause infections with high morbidity and mortality. Limited treatment options are available, though new therapies have been developed. Pipeline agents are likely to have a place in therapy for the treatment of infections caused by KPC-producing isolates.
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Affiliation(s)
- Ann Marie Porreca
- Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, PA, USA
| | - Kaede V Sullivan
- Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Jason C Gallagher
- Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, PA, USA.
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110
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Synergistic Activity of Colistin/Fosfomycin Combination against Carbapenemase-Producing Klebsiella pneumoniae in an In Vitro Pharmacokinetic/Pharmacodynamic Model. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5720417. [PMID: 29850537 PMCID: PMC5937563 DOI: 10.1155/2018/5720417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/27/2018] [Accepted: 03/20/2018] [Indexed: 11/18/2022]
Abstract
Carbapenemase-producing Klebsiella pneumoniae is globally recognized as one of the greatest threats to public health, and combination therapy may be the chemotherapeutic option. In the present study, we aimed to evaluate the antibacterial effects of colistin/fosfomycin combination against carbapenemase-producing K. pneumoniae. The antibacterial effects were determined in a one-compartment in vitro pharmacokinetic model over a period of 24 h. The initial inoculum was 108 CFU/mL. Low, medium, and high Cmax values of colistin at 0.5, 2, and 5 mg/L as well as Cmax of fosfomycin at 100 mg/L were simulated in the model. Doses of both colistin and fosfomycin were given every 8 h until 24 h. For the colistin- and fosfomycin-susceptible isolate KP47, three combination regimens showed greater killing effect compared with colistin monotherapy. The greatest killing effect was observed in combination regimen containing 5 mg/L colistin. For colistin-heteroresistant and fosfomycin-susceptible isolate KP79, combination regimen containing low dose colistin (0.5 mg/L) showed no synergistic or additive effects. However, combination regimens containing 2 and 5 mg/L colistin maintained the bactericidal effect until 24 h compared with colistin monotherapy. For colistin-heteroresistant and fosfomycin-resistant isolates KP42 and KP11, bactericidal activity was barely enhanced by combination regimens. Moreover, combination regimen containing 5 mg/L colistin could only prevent the emergence of colistin-resistant subpopulation in colistin and fosfomycin-susceptible isolate. It is necessary to know the resistant patterns of the K. pneumoniae before using combination of colistin and fosfomycin in clinical practice.
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111
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Mendelson M, Brink A, Gouws J, Mbelle N, Naidoo V, Pople T, Schellack N, van Vuuren M, Rees H. The One Health stewardship of colistin as an antibiotic of last resort for human health in South Africa. THE LANCET. INFECTIOUS DISEASES 2018; 18:e288-e294. [PMID: 29673734 DOI: 10.1016/s1473-3099(18)30119-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 11/20/2017] [Accepted: 12/19/2017] [Indexed: 10/17/2022]
Abstract
Increasing reliance on antibiotics of last resort to treat the rising numbers of multidrug-resistant bacterial infections in people has focused attention on how shared-use antibiotics are managed and regulated across human and animal health. Discussions at international and national levels have intensified since the identification of new plasmid-mediated genes for colistin resistance in 2016, first in China and subsequently in many other countries, removing the last line of defense against multidrug-resistant Gram-negative bacterial infections with carbapenem resistance. South Africa has reacted to this threat by doing a situational analysis and review of the existing legislation concerning colistin use in animals and people, to inform which course of action to take. The experiences shared in this Personal View outline the process, institution of governance with widespread stakeholder engagement, surveillance, and interventions that South Africa has taken towards optimising the shared use of colistin. The instigation of stewardship guided by the principles of the One Health concept for shared-use antibiotics at the country level is a crucial component of any action plan to combat antibiotic resistance, and is as relevant to other existing antibiotics and new chemical entities that will be forthcoming from an invigorated antibiotic pipeline as it is to colistin.
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Affiliation(s)
- Marc Mendelson
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa.
| | - Adrian Brink
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa; Ampath National Laboratory Services, Milpark Hospital, Johannesburg, South Africa
| | - Joey Gouws
- South African Medicines Control Council, Department of Health, Pretoria, South Africa
| | - Nontombi Mbelle
- Department of Medical Microbiology, University of Pretoria, Pretoria, South Africa
| | - Vinny Naidoo
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | | | - Natalie Schellack
- Division of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, South Africa
| | - Moritz van Vuuren
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Helen Rees
- South African Medicines Control Council, Department of Health, Pretoria, South Africa; Wits Reproductive Health and HIV Institute, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa; London School of Hygiene & Tropical Medicine, London, UK
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112
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Martin RM, Bachman MA. Colonization, Infection, and the Accessory Genome of Klebsiella pneumoniae. Front Cell Infect Microbiol 2018; 8:4. [PMID: 29404282 PMCID: PMC5786545 DOI: 10.3389/fcimb.2018.00004] [Citation(s) in RCA: 467] [Impact Index Per Article: 77.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/05/2018] [Indexed: 12/22/2022] Open
Abstract
Klebsiella pneumoniae is a Gram-negative pathogen that has a large accessory genome of plasmids and chromosomal gene loci. This accessory genome divides K. pneumoniae strains into opportunistic, hypervirulent, and multidrug-resistant groups and separates K. pneumoniae from two closely related species, Klebsiella variicola and Klebsiella quasipneumoniae. Some strains of K. pneumoniae act as opportunistic pathogens, infecting critically ill and immunocompromised patients. These K. pneumoniae are a common cause of health-care associated infections including pneumonia, urinary tract infections (UTIs), and bloodstream infections. K. variicola and K. quasipneumoniae are often clinically indistinguishable from opportunistic K. pneumoniae. Other strains of K. pneumoniae are hypervirulent, infecting healthy people in community settings and causing severe infections including pyogenic liver abscess, endophthalmitis, and meningitis. A third group of K. pneumoniae encode carbapenemases, making them highly antibiotic-resistant. These strains act as opportunists but are exceedingly difficult to treat. All of these groups of K. pneumoniae and related species can colonize the gastrointestinal tract, and the accessory genome may determine if a colonizing strain remains asymptomatic or progresses to cause disease. This review will explore the associations between colonization and infection with opportunistic, antibiotic-resistant, and hypervirulent K. pneumoniae strains and the role of the accessory genome in distinguishing these groups and related species. As K. pneumoniae infections become progressively more difficult to treat in the face of antibiotic resistance and hypervirulent strains, an increased understanding of the epidemiology and pathogenesis of these bacteria is vital.
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Affiliation(s)
| | - Michael A. Bachman
- Department of Pathology, Michigan Medicine, University of Michigan, Ann Arbor, MI, United States
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113
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Abstract
The test is inexpensive, easy to perform, sensitive, specific, and can be completed in <2 hours. For identification of polymyxin resistance in Enterobacteriaceae, we developed a rapid test that detects glucose metabolization associated with bacterial growth in the presence of a defined concentration of colistin or polymyxin B. Formation of acid metabolites is evidenced by a color change (orange to yellow) of a pH indicator (red phenol). To evaluate the test, we used bacterial colonies of 135 isolates expressing various mechanisms of colistin resistance (intrinsic, chromosomally encoded, and plasmid-mediated MCR-1) and 65 colistin-susceptible isolates. Sensitivity and specificity were 99.3% and 95.4%, respectively, compared with the standard broth microdilution method. This new test is inexpensive, easy to perform, sensitive, specific, and can be completed in <2 hours. It could be useful in countries facing endemic spread of carbapenemase producers and for which polymyxins are last-resort drugs.
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Abdul Momin MHF, Bean DC, Hendriksen RS, Haenni M, Phee LM, Wareham DW. CHROMagar COL-APSE: a selective bacterial culture medium for the isolation and differentiation of colistin-resistant Gram-negative pathogens. J Med Microbiol 2017; 66:1554-1561. [DOI: 10.1099/jmm.0.000602] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Muhd Haziq F. Abdul Momin
- Antimicrobial Research Group, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - David C. Bean
- School of Applied and Biomedical Sciences, Federation University Australia, Ballarat, Australia
| | - Rene S. Hendriksen
- Technical University of Denmark, National Food Institute, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics, European Union Reference Laboratory for Antimicrobial Resistance (EURL-AMR), Kgs Lyngby, Denmark DK-2800, Denmark
| | - Marisa Haenni
- Unité Antibiorésistance et Virulence Bactériennes, Université Lyon-ANSES Site de Lyon, Lyon, France
| | - Lynette M. Phee
- Antimicrobial Research Group, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Division of Infection, Barts Health NHS Trust, London, UK
| | - David W. Wareham
- Antimicrobial Research Group, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Division of Infection, Barts Health NHS Trust, London, UK
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115
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Polymyxins: Antibacterial Activity, Susceptibility Testing, and Resistance Mechanisms Encoded by Plasmids or Chromosomes. Clin Microbiol Rev 2017; 30:557-596. [PMID: 28275006 DOI: 10.1128/cmr.00064-16] [Citation(s) in RCA: 910] [Impact Index Per Article: 130.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Polymyxins are well-established antibiotics that have recently regained significant interest as a consequence of the increasing incidence of infections due to multidrug-resistant Gram-negative bacteria. Colistin and polymyxin B are being seriously reconsidered as last-resort antibiotics in many areas where multidrug resistance is observed in clinical medicine. In parallel, the heavy use of polymyxins in veterinary medicine is currently being reconsidered due to increased reports of polymyxin-resistant bacteria. Susceptibility testing is challenging with polymyxins, and currently available techniques are presented here. Genotypic and phenotypic methods that provide relevant information for diagnostic laboratories are presented. This review also presents recent works in relation to recently identified mechanisms of polymyxin resistance, including chromosomally encoded resistance traits as well as the recently identified plasmid-encoded polymyxin resistance determinant MCR-1. Epidemiological features summarizing the current knowledge in that field are presented.
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High-Level Resistance to Colistin Mediated by Various Mutations in the crrB Gene among Carbapenemase-Producing Klebsiella pneumoniae. Antimicrob Agents Chemother 2017; 61:AAC.01423-17. [PMID: 28874377 DOI: 10.1128/aac.01423-17] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/30/2017] [Indexed: 11/20/2022] Open
Abstract
Mutations in crrAB genes encoding a two-component regulator involved in modifications of lipopolysaccharide were searched for among a collection of colistin-resistant Klebsiella pneumoniae isolates. Four isolates, respectively, producing carbapenemases NDM-1, OXA-181, or KPC-2 showed mutated CrrB proteins compared with those in wild-type strains. Complementation assays with a wild-type CrrB protein restored the susceptibility to colistin in all cases, confirming the involvement of the identified substitutions in the resistance phenotype.
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117
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Denervaud-Tendon V, Poirel L, Connolly LE, Krause KM, Nordmann P. Plazomicin activity against polymyxin-resistant Enterobacteriaceae, including MCR-1-producing isolates. J Antimicrob Chemother 2017; 72:2787-2791. [DOI: 10.1093/jac/dkx239] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/15/2017] [Indexed: 11/13/2022] Open
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Telke AA, Olaitan AO, Morand S, Rolain JM. soxRS induces colistin hetero-resistance in Enterobacter asburiae and Enterobacter cloacae by regulating the acrAB-tolC efflux pump. J Antimicrob Chemother 2017; 72:2715-2721. [DOI: 10.1093/jac/dkx215] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 06/07/2017] [Indexed: 11/13/2022] Open
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Schürch AC, van Schaik W. Challenges and opportunities for whole-genome sequencing-based surveillance of antibiotic resistance. Ann N Y Acad Sci 2017; 1388:108-120. [PMID: 28134443 DOI: 10.1111/nyas.13310] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 12/13/2022]
Abstract
Infections caused by drug-resistant bacteria are increasingly reported across the planet, and drug-resistant bacteria are recognized to be a major threat to public health and modern medicine. In this review, we discuss how whole-genome sequencing (WGS)-based approaches can contribute to the surveillance of the emergence and spread of antibiotic resistance. We outline the characteristics of sequencing technologies that are currently most used for WGS (Illumina short-read technologies and the long-read sequencing platforms developed by Pacific Biosciences and Oxford Nanopore). The challenges posed by the analysis of sequencing data sets for antimicrobial-resistance determinants and the solutions offered by modern bioinformatics tools are discussed. Finally, we illustrate the power of WGS-based surveillance of antimicrobial resistance by summarizing recent studies on the spread of the multidrug-resistant opportunistic pathogen Klebsiella pneumoniae and the transferable colistin-resistance gene mcr-1, in which high-throughput WGS analyses played essential roles. The implementation of WGS for surveillance of antibiotic-resistant bacteria is technically feasible and cost effective and provides actionable results with reference to infection control. Consequently, the time has come for laboratories to implement routine genome sequencing as part of their surveillance programs for antibiotic-resistant bacteria.
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Affiliation(s)
- Anita C Schürch
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
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120
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Colistin and Polymyxin B Susceptibility Testing for Carbapenem-Resistant and mcr-Positive Enterobacteriaceae: Comparison of Sensititre, MicroScan, Vitek 2, and Etest with Broth Microdilution. J Clin Microbiol 2017; 55:2609-2616. [PMID: 28592552 DOI: 10.1128/jcm.00268-17] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/03/2017] [Indexed: 11/20/2022] Open
Abstract
Colistin and polymyxin B remain part of the last line of antibiotics for multidrug-resistant Gram-negative bacteria, such as carbapenem-resistant Enterobacteriaceae Current joint EUCAST-CLSI recommendations are for broth microdilution (BMD) to be performed for MIC testing of colistin. Commercial susceptibility testing methods were evaluated and compared against the reference BMD, using a susceptibility breakpoint of ≤2 mg/liter for both colistin and polymyxin B. Seventy-six Enterobacteriaceae were included, of which 21 were mcr-1 positive (18 Escherichia coli isolates, 2 Klebsiella pneumoniae isolates, and 1 Enterobacter aerogenes isolate). Rates of essential agreement (EA) of colistin test results between BMD and Vitek 2, Sensititre, and Etest were 93.4%, 89.5%, and 75.0%, respectively. Rates of EA of polymyxin B test results between BMD and Vitek 2, Sensititre, and Etest were 96.1%, 96.1%, and 48.7%, respectively. A positive MIC correlation with a categorical agreement of >90% was achieved for Sensititre (colistin Spearman's ρ = 0.863, and polymyxin B Spearman's ρ = 0.877) and Vitek 2 (polymyxin B [only] Spearman's ρ = 0.8917). Although a positive MIC correlation (Spearman's ρ = 0.873) with the reference method was achieved for colistin testing with Vitek 2, categorical agreement was <90%, with very major error rates of 36%. Correlation with the Etest MIC was lower, with very major error rates of 12% (colistin) and 26.1% (polymyxin B). MicroScan (colistin) categorical agreement was 88.2%, with a very major error rate of 4%. Colistin MICs for 15 of the 21 mcr-1-positive isolates were >2 mg/liter, and polymyxin MICs for 17 of them were >2 mg/liter by broth microdilution. The use of a lower breakpoint of ≤1 mg/liter further improves detection of mcr-1 for all testing methods. However, further data on the correlation between MICs and clinical outcome are required to determine the most suitable breakpoint to guide clinical management.
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121
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Deciphering Heteroresistance to Colistin in a Klebsiella pneumoniae Isolate from Marseille, France. Antimicrob Agents Chemother 2017; 61:AAC.00356-17. [PMID: 28416544 DOI: 10.1128/aac.00356-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/06/2017] [Indexed: 11/20/2022] Open
Abstract
Here, we report the description of a colistin-heteroresistant Klebsiella pneumoniae isolate fortuitously isolated from the stool sample of a patient with suspicion of tuberculosis in a public hospital of Marseille, France. In the colistin-resistant subpopulation, a mutation in the mgrB gene leading to a premature stop codon was found, and the hypermucoviscous phenotype was lost. Susceptibility to other antibiotics remained unchanged. To our knowledge, this is the first identification of such a colistin-heteroresistant Klebsiella pneumoniae isolate in France.
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122
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Neuner EA, Gallagher JC. Pharmacodynamic and pharmacokinetic considerations in the treatment of critically Ill patients infected with carbapenem-resistant Enterobacteriaceae. Virulence 2017; 8:440-452. [PMID: 27589330 PMCID: PMC5477717 DOI: 10.1080/21505594.2016.1221021] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 01/20/2023] Open
Abstract
Carbapenem-Resistant Enterobacteriaceae (CRE) are an emerging healthcare crisis. Infections due to CRE are associated with high morbidity and mortality, especially in critically ill patients. Due to the multi-drug resistant nature of these infections only limited treatment options are available. Antimicrobials that have been described for the treatment of CRE infections include carbapenems, polymyxins, fosfomycin, tigecycline, aminoglycosides, and ceftazidime-avibactam. Given the limited treatment options it is imperative the pharmacokinetic and pharmacodynamics (PK-PD) characteristics of these agents are considered to optimize treatment regimens. This review will focus on the PK-PD challenges of the current treatment options for CRE infections.
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Affiliation(s)
| | - Jason C. Gallagher
- Department of Pharmacy Practice, Infectious Diseases, Temple University, Philadelphia, PA, USA
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123
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New Polymyxin B Dosing Strategies To Fortify Old Allies in the War against KPC-2-Producing Klebsiella pneumoniae. Antimicrob Agents Chemother 2017; 61:AAC.02023-16. [PMID: 28167549 DOI: 10.1128/aac.02023-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 01/30/2017] [Indexed: 11/20/2022] Open
Abstract
Pharmacodynamics of a polymyxin B, meropenem, and rifampin triple combination were examined against Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) ST258. In time-kill experiments against three KPC-Kp isolates, triple combination generated 8.14, 8.19, and 8.29 log10 CFU/ml reductions within 24 h. In the hollow-fiber infection model, the triple combination caused maximal killing of 5.16 log10 CFU/ml at 78 h and the time required for regrowth was more than doubled versus the 2-drug combinations. Remarkably, combinations with a high single-dose polymyxin B burst plus rifampin preserved KPC-Kp polymyxin susceptibility (MIC240 h = 0.5 mg/liter) versus the same combination with traditionally dosed polymyxin B, where resistance was amplified (MIC240 h = 32 mg/liter).
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124
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Jeannot K, Bolard A, Plésiat P. Resistance to polymyxins in Gram-negative organisms. Int J Antimicrob Agents 2017; 49:526-535. [PMID: 28163137 DOI: 10.1016/j.ijantimicag.2016.11.029] [Citation(s) in RCA: 255] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/10/2016] [Accepted: 11/25/2016] [Indexed: 12/30/2022]
Abstract
Polymyxins have recently been re-introduced into the therapeutic arsenal to combat infections caused by multidrug-resistant Gram-negative bacteria. However, the emergence of strains resistant to these last-resort drugs is becoming a critical issue in a growing number of countries. Both intrinsic and transferable mechanisms of polymyxin resistance have been characterised. These mechanisms as well as the epidemiological data regarding four relevant bacterial pathogens (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa) are considered in this review. A special focus is made on plasmid-mediated resistance and the spread of mcr genes.
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Affiliation(s)
- Katy Jeannot
- Laboratoire de bactériologie, Centre national de référence (CNR) de la résistance aux antibiotiques, Centre hospitalier universitaire (CHRU) de Besançon, boulevard Fleming, 25000 Besançon, France.
| | - Arnaud Bolard
- Laboratoire de bactériologie, Centre national de référence (CNR) de la résistance aux antibiotiques, Centre hospitalier universitaire (CHRU) de Besançon, boulevard Fleming, 25000 Besançon, France
| | - Patrick Plésiat
- Laboratoire de bactériologie, Centre national de référence (CNR) de la résistance aux antibiotiques, Centre hospitalier universitaire (CHRU) de Besançon, boulevard Fleming, 25000 Besançon, France
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125
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Mechanisms of Increased Resistance to Chlorhexidine and Cross-Resistance to Colistin following Exposure of Klebsiella pneumoniae Clinical Isolates to Chlorhexidine. Antimicrob Agents Chemother 2016; 61:AAC.01162-16. [PMID: 27799211 DOI: 10.1128/aac.01162-16] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 10/09/2016] [Indexed: 12/16/2022] Open
Abstract
Klebsiella pneumoniae is an opportunistic pathogen that is often difficult to treat due to its multidrug resistance (MDR). We have previously shown that K. pneumoniae strains are able to "adapt" (become more resistant) to the widely used bisbiguanide antiseptic chlorhexidine. Here, we investigated the mechanisms responsible for and the phenotypic consequences of chlorhexidine adaptation, with particular reference to antibiotic cross-resistance. In five of six strains, adaptation to chlorhexidine also led to resistance to the last-resort antibiotic colistin. Here, we show that chlorhexidine adaptation is associated with mutations in the two-component regulator phoPQ and a putative Tet repressor gene (smvR) adjacent to the major facilitator superfamily (MFS) efflux pump gene, smvA Upregulation of smvA (10- to 27-fold) was confirmed in smvR mutant strains, and this effect and the associated phenotype were suppressed when a wild-type copy of smvR was introduced on plasmid pACYC. Upregulation of phoPQ (5- to 15-fold) and phoPQ-regulated genes, pmrD (6- to 19-fold) and pmrK (18- to 64-fold), was confirmed in phoPQ mutant strains. In contrast, adaptation of K. pneumoniae to colistin did not result in increased chlorhexidine resistance despite the presence of mutations in phoQ and elevated phoPQ, pmrD, and pmrK transcript levels. Insertion of a plasmid containing phoPQ from chlorhexidine-adapted strains into wild-type K. pneumoniae resulted in elevated expression levels of phoPQ, pmrD, and pmrK and increased resistance to colistin, but not chlorhexidine. The potential risk of colistin resistance emerging in K. pneumoniae as a consequence of exposure to chlorhexidine has important clinical implications for infection prevention procedures.
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126
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The polymyxin B-induced transcriptomic response of a clinical, multidrug-resistant Klebsiella pneumoniae involves multiple regulatory elements and intracellular targets. BMC Genomics 2016; 17:737. [PMID: 27801293 PMCID: PMC5088521 DOI: 10.1186/s12864-016-3070-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Background The emergence of multidrug-resistant Klebsiella pneumoniae is a major public health concern. Many K. pneumoniae infections can only be treated when resorting to last-line drugs such as polymyxin B (PB). However, resistance to this antibiotic is also observed, although insufficient information is described on its mode of action as well as the mechanisms used by resistant bacteria to evade its effects. We aimed to study PB resistance and the influence of abiotic stresses in a clinical K. pneumoniae strain using whole transcriptome profiling. Results We sequenced 12 cDNA libraries of K. pneumoniae Kp13 bacteria, from two biological replicates of the original strain Kp13 (Kp13) and five derivative strains: induced high-level PB resistance in acidic pH (Kp13pH), magnesium deprivation (Kp13Mg), high concentrations of calcium (Kp13Ca) and iron (Kp13Fe), and a control condition with PB (Kp13PolB). Our results show the involvement of multiple regulatory loci that differentially respond to each condition as well as a shared gene expression response elicited by PB treatment, and indicate the participation of two-regulatory components such as ArcA-ArcB, which could be involved in re-routing the K. pneumoniae metabolism following PB treatment. Modules of co-expressed genes could be determined, which correlated to growth in acid stress and PB exposure. We hypothesize that polymyxin B induces metabolic shifts in K. pneumoniae that could relate to surviving against the action of this antibiotic. Conclusions We obtained whole transcriptome data for K. pneumoniae under different environmental conditions and PB treatment. Our results supports the notion that the K. pneumoniae response to PB exposure goes beyond damaged membrane reconstruction and involves recruitment of multiple gene modules and intracellular targets. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3070-y) contains supplementary material, which is available to authorized users.
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127
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Genomic Characterization of Colistin Heteroresistance in Klebsiella pneumoniae during a Nosocomial Outbreak. Antimicrob Agents Chemother 2016; 60:6837-6843. [PMID: 27600049 DOI: 10.1128/aac.01344-16] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/28/2016] [Indexed: 01/11/2023] Open
Abstract
Klebsiella pneumoniae is emerging as an important nosocomial pathogen due to its rapidly increasing multidrug resistance, which has led to a renewed interest in polymyxin antibiotics, such as colistin, as antibiotics of last resort. However, heteroresistance (i.e., the presence of a subpopulation of resistant bacteria in an otherwise susceptible culture) may hamper the effectiveness of colistin treatment in patients. In a previous study, we showed that colistin resistance among extended-spectrum-beta-lactamase (ESBL)-producing K. pneumoniae isolates emerged after the introduction of selective digestive tract decontamination (SDD) in an intensive care unit (ICU). In this study, we investigated heteroresistance to colistin among ESBL-producing K. pneumoniae isolates by using population analysis profiles (PAPs). We used whole-genome sequencing (WGS) to identify the mutations that were associated with the emergence of colistin resistance in these K. pneumoniae isolates. We found five heteroresistant subpopulations, with colistin MICs ranging from 8 to 64 mg/liter, which were derived from five clonally related, colistin-susceptible clinical isolates. WGS revealed the presence of mutations in the lpxM, mgrB, phoQ, and yciM genes in colistin-resistant K. pneumoniae isolates. In two strains, mgrB was inactivated by an IS3-like or ISKpn14 insertion sequence element. Complementation in trans with the wild-type mgrB gene resulted in these strains reverting to colistin susceptibility. The MICs for colistin-susceptible strains increased 2- to 4-fold in the presence of the mutated phoQ, lpxM, and yciM alleles. In conclusion, the present study indicates that heteroresistant K. pneumoniae subpopulations may be selected for upon exposure to colistin. Mutations in mgrB and phoQ have previously been associated with colistin resistance, but we provide experimental evidence for roles of mutations in the yciM and lpxM genes in the emergence of colistin resistance in K. pneumoniae.
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128
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Cherkaoui A, Diene SM, Renzoni A, Emonet S, Renzi G, François P, Schrenzel J. Imipenem heteroresistance in nontypeable Haemophilus influenzae is linked to a combination of altered PBP3, slow drug influx and direct efflux regulation. Clin Microbiol Infect 2016; 23:118.e9-118.e19. [PMID: 27756711 DOI: 10.1016/j.cmi.2016.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/01/2016] [Accepted: 10/10/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To investigate the potential roles of PBPs, efflux pumps and slow drug influx for imipenem heteroresistance in nontypeable Haemophilus influenzae (NTHi). METHODS Fifty-nine NTHi clinical isolates examined in this study were collected at Geneva University Hospitals between 2009 and 2014. Alterations in PBPs were investigated by gene sequencing. To evaluate the affinities of the PBPs to imipenem, steady-state concentration-response experiments were carried out using imipenem in a competition assay with Bocillin-FL. The effect of the carbonyl cyanide m-chlorophenylhydrazone (CCCP) on imipenem susceptibility was assessed using broth dilution and viable cell counting. Using whole-genome sequencing, we explored the potential roles of outer membrane protein P2 (OmpP2), LytM proteins and the dcw gene cluster in imipenem heteroresistance. RESULTS All 46 imipenem-heteroresistant isolates (IMIhR) harboured amino acid substitutions in the ftsI gene, which encodes PBP3, corresponding to 25 different mutation patterns that varied from the ftsI gene mutation patterns found in imipenem-susceptible isolates. Among all PBPs, the highest affinity to imipenem was documented for PBP3 (IC50, 0.004 μg/mL). Different amino acid substitutions and insertions were noted in OmpP2, suggesting a relationship with imipenem heteroresistance. The IMIhR isolates were affected by CCCP differently and displayed a higher percentage of killing by imipenem in CCCP-treated cells at concentrations ranging between 0.5 and 8 μg/mL. CONCLUSIONS The present study provides robust evidence indicating that in combination with the altered PBP3, the slowed drug influx and its enhanced efflux due to the loss of regulation led to the development of imipenem heteroresistance in NTHi.
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Affiliation(s)
- A Cherkaoui
- Bacteriology Laboratory, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland.
| | - S M Diene
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - A Renzoni
- Bacteriology Laboratory, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - S Emonet
- Bacteriology Laboratory, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - G Renzi
- Bacteriology Laboratory, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - P François
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - J Schrenzel
- Bacteriology Laboratory, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland; Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
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129
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Karaiskos I, Souli M, Galani I, Giamarellou H. Colistin: still a lifesaver for the 21st century? Expert Opin Drug Metab Toxicol 2016; 13:59-71. [DOI: 10.1080/17425255.2017.1230200] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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130
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Baron S, Hadjadj L, Rolain JM, Olaitan AO. Molecular mechanisms of polymyxin resistance: knowns and unknowns. Int J Antimicrob Agents 2016; 48:583-591. [PMID: 27524102 DOI: 10.1016/j.ijantimicag.2016.06.023] [Citation(s) in RCA: 288] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/14/2016] [Accepted: 06/23/2016] [Indexed: 12/19/2022]
Abstract
Colistin, also referred to as polymyxin E, is an effective antibiotic against most multidrug-resistant Gram-negative bacteria and is currently used as a last-line drug for treating severe bacterial infections. Colistin resistance has increased gradually for the last few years, and knowledge of its multifaceted mechanisms is expanding. This includes the newly discovered plasmid-mediated colistin resistance gene mcr-1, which has been detected in over 20 countries within 3 months of its first report. We previously reported all of the known mechanisms of polymyxin resistance in our first review in 2014, but an update seems necessary in 2016, considering the significant recent discoveries that have been made in this domain. This review provides an update about what is already known, what is new, and some unresolved questions with respect to colistin resistance.
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Affiliation(s)
- Sophie Baron
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France
| | - Linda Hadjadj
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France
| | - Jean-Marc Rolain
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France.
| | - Abiola Olumuyiwa Olaitan
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), CNRS-IRD UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France.
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131
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Hjort K, Nicoloff H, Andersson DI. Unstable tandem gene amplification generates heteroresistance (variation in resistance within a population) to colistin in Salmonella enterica. Mol Microbiol 2016; 102:274-289. [PMID: 27381382 DOI: 10.1111/mmi.13459] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/01/2016] [Accepted: 07/04/2016] [Indexed: 11/30/2022]
Abstract
Heteroresistance, a phenomenon where subpopulations of a bacterial isolate exhibit different susceptibilities to an antibiotic, is a growing clinical problem where the underlying genetic mechanisms in most cases remain unknown. We isolated colistin resistant mutants in Escherichia coli and Salmonella enterica serovar Typhimurium at different concentrations of colistin. Genetic analysis showed that genetically stable pmrAB point mutations were responsible for colistin resistance during selection at high drug concentrations for both species and at low concentrations for E. coli. In contrast, for S. Typhimurium mutants selected at low colistin concentrations, amplification of different large chromosomal regions conferred a heteroresistant phenotype. All amplifications included the pmrD gene, which encodes a positive regulator that up-regulates proteins that modify lipid A, and as a result increase colistin resistance. Inactivation and over-expression of the pmrD gene prevented and conferred resistance, respectively, demonstrating that the PmrD protein is required and sufficient to confer resistance. The heteroresistance phenotype is explained by the variable gene dosage of pmrD in a population, where sub-populations with different copy number of the pmrD gene show different levels of colistin resistance. We propose that variability in gene copy number of resistance genes can explain the heteroresistance observed in clinically isolated pathogenic bacteria.
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Affiliation(s)
- Karin Hjort
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Hervé Nicoloff
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
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132
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Guérin F, Isnard C, Sinel C, Morand P, Dhalluin A, Cattoir V, Giard JC. Cluster-dependent colistin hetero-resistance inEnterobacter cloacaecomplex. J Antimicrob Chemother 2016; 71:3058-3061. [DOI: 10.1093/jac/dkw260] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/25/2016] [Accepted: 06/01/2016] [Indexed: 12/22/2022] Open
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133
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Rapid Detection of Polymyxin-Resistant Enterobacteriaceae from Blood Cultures. J Clin Microbiol 2016; 54:2273-7. [PMID: 27307457 DOI: 10.1128/jcm.00918-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/08/2016] [Indexed: 11/20/2022] Open
Abstract
Enterobacterial strains resistant to polymyxins are being increasingly reported worldwide. The conventional methods for detection of colistin-resistant isolates such as broth microdilution remain time-consuming (24 to 48 h), and methods such as disc diffusion and Etest are not reliable. Recently, the rapid polymyxin NP test was developed for rapid identification of polymyxin-resistant Enterobacteriaceae This test is based on the detection of glucose metabolism related to bacterial growth in the presence of a defined concentration of colistin (or polymyxin B). The formation of acid metabolites is evidenced by a color change of a pH indicator (red phenol) in less than 2 h. In this study, the polymyxin NP test was evaluated for detection of colistin-resistant Enterobacteriaceae directly from blood cultures. The test was performed with 73 blood culture sets (either spiked or clinical blood cultures) with various enterobacterial species. The test exhibited excellent discrimination between polymyxin-resistant and polymyxin-susceptible enterobacterial isolates, and results are obtained from blood cultures within 4 h. It is easy to perform and requires neither subculture nor a centrifugation step. This test is rapid, specific, and sensitive and allows early identification of polymyxin-resistant Enterobacteriaceae directly from blood cultures.
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135
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Amino Acid Substitutions of CrrB Responsible for Resistance to Colistin through CrrC in Klebsiella pneumoniae. Antimicrob Agents Chemother 2016; 60:3709-16. [PMID: 27067316 DOI: 10.1128/aac.00009-16] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/31/2016] [Indexed: 12/21/2022] Open
Abstract
Colistin is a last-resort antibiotic for treatment of carbapenem-resistant Klebsiella pneumoniae A recent study indicated that missense mutations in the CrrB protein contribute to colistin resistance. In our previous study, mechanisms of colistin resistance were defined in 17 of 26 colistin-resistant K. pneumoniae clinical isolates. Of the remaining nine strains, eight were highly resistant to colistin. In the present study, crrAB sequences were determined for these eight strains. Six separate amino acid substitutions in CrrB (Q10L, Y31H, W140R, N141I, P151S, and S195N) were detected. Site-directed mutagenesis was used to generate crrB loci harboring individual missense mutations; introduction of the mutated genes into a susceptible strain, A4528, resulted in 64- to 1,024-fold increases in colistin MICs. These crrB mutants showed increased accumulation of H239_3062, H239_3059, pmrA, pmrC, and pmrH transcripts by quantitative reverse transcription (qRT)-PCR. Deletion of H239_3062 (but not that of H239_3059) in the A4528 crrB(N141I) strain attenuated resistance to colistin, and H239_3062 was accordingly named crrC Similarly, accumulation of pmrA, pmrC, and pmrH transcripts induced by crrB(N141I) was significantly attenuated upon deletion of crrC Complementation of crrC restored resistance to colistin and accumulation of pmrA, pmrC, and pmrH transcripts in a crrB(N141I) ΔcrrC strain. In conclusion, novel individual CrrB amino acid substitutions (Y31H, W140R, N141I, P151S, and S195N) were shown to be responsible for colistin resistance. We hypothesize that CrrB mutations induce CrrC expression, thereby inducing elevated expression of the pmrHFIJKLM operon and pmrC (an effect mediated via the PmrAB two-component system) and yielding increased colistin resistance.
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136
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Silva A, Sousa AM, Alves D, Lourenço A, Pereira MO. Heteroresistance to colistin in Klebsiella pneumoniae is triggered by small colony variants sub-populations within biofilms. Pathog Dis 2016; 74:ftw036. [PMID: 27140200 DOI: 10.1093/femspd/ftw036] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2016] [Indexed: 01/29/2023] Open
Abstract
The emergence of Klebsiella pneumoniae multidrug-resistant strains paves the way to the re-introduction of colistin as a salvage therapy. However, recent planktonic studies have reported several cases of heteroresistance to this antimicrobial agent. The aim of this present work was to gain better understanding about the response of K. pneumoniae biofilms to colistin antibiotherapy and inspect the occurrence of heteroresistance in biofilm-derived cells. Biofilm formation and its susceptibility to colistin were evaluated through the determination of biofilm-cells viability. The profiling of planktonic and biofilm cell populations was conducted to assess the occurrence of heteroresistance. Colony morphology was further characterized in order to inspect the potential role of colistin in K. pneumoniae phenotypic differentiation. Results show that K. pneumoniae was susceptible to colistin in its planktonic form, but biofilms presented enhanced resistance. Population analysis profiles pointed out that K. pneumoniae manifest heteroresistance to colistin only when grown in biofilm arrangements, and it was possible to identify a resistant sub-population presenting a small colony morphology (diameter around 5 mm). To the best of our knowledge, this is the first report linking heteroresistance to biofilm formation and a morphological distinctive sub-population. Moreover, this is the first evidence that biofilm formation can trigger the emergence of heteroresistance in an apparently susceptible strain.
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Affiliation(s)
- Ana Silva
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Diana Alves
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Anália Lourenço
- ESEI-Escuela Superior de Ingeniería Informática, Universidad de Vigo, Ourense, Spain CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
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138
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Colistin Resistance Caused by Inactivation of the MgrB Regulator Is Not Associated with Decreased Virulence of Sequence Type 258 KPC Carbapenemase-Producing Klebsiella pneumoniae. Antimicrob Agents Chemother 2016; 60:2509-12. [PMID: 26824959 DOI: 10.1128/aac.02981-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/07/2016] [Indexed: 01/10/2023] Open
Abstract
Using aGalleria mellonellaanimal model, we compared the virulence of two sequence type 258 (ST258) KPC-producingKlebsiella pneumoniaestrains, which were representative of the two clades of this clonal lineage, with that of isogenic colistin-resistantmgrBmutants. With both strains, themgrBmutants did not exhibit modification in virulence. In theG. mellonellamodel, the clade 1 strain (capsular typecps-1[wzi29, producing KPC-2]) was significantly more virulent than the clade 2 strain (capsular typecps-2[wzi154, producing KPC-3]).
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139
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Correlation of β-Lactamase Production and Colistin Resistance among Enterobacteriaceae Isolates from a Global Surveillance Program. Antimicrob Agents Chemother 2015; 60:1385-92. [PMID: 26666920 DOI: 10.1128/aac.01870-15] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 12/05/2015] [Indexed: 02/08/2023] Open
Abstract
The increasing use of carbapenems for treating multidrug-resistant (MDR) Gram-negative bacterial infections has contributed to the global dissemination of carbapenem-resistant Enterobacteriaceae (CRE). Serine and metallo-β-lactamases (MBLs) that hydrolyze carbapenems have become prevalent and endemic in some countries, necessitating the use of older classes of agents, such as colistin. A total of 19,719 isolates of Enterobacteriaceae (excluding Proteeae and Serratia spp., which have innate resistance to colistin) were collected from infected patients during 2012 and 2013 in a global surveillance program and tested for antimicrobial susceptibility using CLSI methods. Isolates of CRE were characterized for carbapenemases and extended-spectrum β-lactamases (ESBLs) by PCR and sequencing. Using EUCAST breakpoints, the rate of colistin susceptibility was 98.4% overall, but it was reduced to 88.0% among 482 carbapenemase-positive isolates. Colistin susceptibility was higher among MBL-positive isolates (92.6%) than those positive for a KPC (87.9%) or OXA-48 (84.2%). Of the agents tested, only tigecycline (MIC90, 2 to 4 μg/ml) and aztreonam-avibactam (MIC90, 0.5 to 1 μg/ml) consistently tested with low MIC values against colistin-resistant, ESBL-positive, and carbapenemase-positive isolates. Among the 309 (1.6%) colistin-resistant isolates from 10 species collected in 38 countries, 58 carried a carbapenemase that included KPCs (38 isolates), MBLs (6 isolates), and OXA-48 (12 isolates). These isolates were distributed globally (16 countries), and 95% were Klebsiella pneumoniae. Thirty-nine (67.2%) isolates carried additional ESBL variants of CTX-M, SHV, and VEB. This sample of Enterobacteriaceae demonstrated a low prevalence of colistin resistance overall. However, the wide geographic dispersion of colistin resistance within diverse genus and species groups and the higher incidence observed among carbapenemase-producing MDR pathogens are concerning.
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140
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Dafopoulou K, Zarkotou O, Dimitroulia E, Hadjichristodoulou C, Gennimata V, Pournaras S, Tsakris A. Comparative Evaluation of Colistin Susceptibility Testing Methods among Carbapenem-Nonsusceptible Klebsiella pneumoniae and Acinetobacter baumannii Clinical Isolates. Antimicrob Agents Chemother 2015; 59:4625-30. [PMID: 26014928 PMCID: PMC4505270 DOI: 10.1128/aac.00868-15] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 05/17/2015] [Indexed: 11/20/2022] Open
Abstract
We compared six colistin susceptibility testing (ST) methods on 61 carbapenem-nonsusceptible Klebsiella pneumoniae (n = 41) and Acinetobacter baumannii (n = 20) clinical isolates with provisionally elevated colistin MICs by routine ST. Colistin MICs were determined by broth microdilution (BMD), BMD with 0.002% polysorbate 80 (P80) (BMD-P80), agar dilution (AD), Etest, Vitek2, and MIC test strip (MTS). BMD was used as the reference method for comparison. The EUCAST-recommended susceptible and resistant breakpoints of ≤2 and >2 μg/ml, respectively, were applied for both K. pneumoniae and A. baumannii. The proportions of colistin-resistant strains were 95.1, 77, 96.7, 57.4, 65.6, and 98.4% by BMD, BMD-P80, AD, Etest, MTS, and Vitek2, respectively. The Etest and MTS methods produced excessive rates of very major errors (VMEs) (39.3 and 31.1%, respectively), while BMD-P80 produced 18% VMEs, AD produced 3.3% VMEs, and Vitek2 produced no VMEs. Major errors (MEs) were rather limited by all tested methods. These data show that gradient diffusion methods may lead to inappropriate colistin therapy. Clinical laboratories should consider the use of automated systems, such as Vitek2, or dilution methods for colistin ST.
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Affiliation(s)
- Konstantina Dafopoulou
- Department of Microbiology, Medical School, University of Athens, Athens, Greece Department of Hygiene and Epidemiology, Medical School, University of Thessaly, Larissa, Greece
| | - Olympia Zarkotou
- Department of Microbiology, Medical School, University of Athens, Athens, Greece
| | | | | | - Vasiliki Gennimata
- Department of Microbiology, Medical School, University of Athens, Athens, Greece
| | - Spyros Pournaras
- Department of Microbiology, Medical School, University of Athens, Athens, Greece
| | - Athanasios Tsakris
- Department of Microbiology, Medical School, University of Athens, Athens, Greece
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141
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Large Nosocomial Outbreak of Colistin-Resistant, Carbapenemase-Producing Klebsiella pneumoniae Traced to Clonal Expansion of an mgrB Deletion Mutant. J Clin Microbiol 2015. [PMID: 26202124 DOI: 10.1128/jcm.01017-15] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe a large hospital outbreak (93 bloodstream infections) of colistin-resistant Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae isolates which was mirrored by increased colistin consumption. The outbreak was mostly traced to the clonal expansion of an mgrB deletion mutant of an ST512 strain that produced KPC-3.
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