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Zhang X, Zeng W, Kong J, Huang Z, Shu H, Tang M, Qian C, Xu C, Zhou T, Ye J. The prevalence and mechanisms of heteroresistance to ceftazidime/avibactam in KPC-producing Klebsiella pneumoniae. J Antimicrob Chemother 2024; 79:1865-1876. [PMID: 38842536 DOI: 10.1093/jac/dkae174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/14/2024] [Indexed: 06/07/2024] Open
Abstract
OBJECTIVES To investigate the prevalence and mechanisms of ceftazidime/avibactam heteroresistance in KPC-producing Klebsiella pneumoniae (KPC-KP) isolates, as well as the role of heteroresistance in the transition of ceftazidime/avibactam susceptibility to resistance. METHODS Clinical KPC-KP isolates were obtained from a tertiary hospital in China from 2016 to 2017 and 2019 to 2020. Antimicrobial susceptibility was determined by the broth microdilution method. Population analysis profiles were used to assess ceftazidime/avibactam heteroresistance. WGS and molecular cloning were conducted to reveal heteroresistance mechanisms and molecular characteristics. RESULTS The findings indicated that the transition of ceftazidime/avibactam susceptibility to resistance during the treatment of KPC-KP infection is primarily attributed to the heteroresistance exhibited by KPC-KP isolates towards ceftazidime/avibactam. Among 355 ceftazidime/avibactam-susceptible KPC-KP isolates (indicating a resistance rate of 0%), 41 (11.55%) exhibited ceftazidime/avibactam heteroresistance, with the primary mechanism being the presence of KPC mutant subpopulations. These KPC variants, arising from point mutations, deletions and insertions, significantly increased ceftazidime/avibactam resistance while alongside enhanced carbapenem susceptibility. Notably, 11 new KPC variants were identified. Furthermore, four heteroresistant isolates were caused by mixed infection involving subpopulations carrying NDM-1 or NDM-5. Phylogenetic analysis indicated that the clonal spread of ST11-KL64 KPC-KP may be correlated with the prevalence of heteroresistance. CONCLUSIONS Ceftazidime/avibactam heteroresistance, primarily driven by pre-existing KPC variants, underscores the importance of considering heteroresistance in ceftazidime/avibactam therapeutics. Awareness of these dynamics is crucial for the effective and sustainable clinical application of ceftazidime/avibactam.
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Affiliation(s)
- Xiaotuan Zhang
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Weiliang Zeng
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jingchun Kong
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Zeyu Huang
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Hongyun Shu
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Miran Tang
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Changrui Qian
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Chunquan Xu
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Tieli Zhou
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jianzhong Ye
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
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2
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Lynch JP, Clark NM, Zhanel GG. Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options. Semin Respir Crit Care Med 2022; 43:97-124. [PMID: 35172361 DOI: 10.1055/s-0041-1741019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.
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Affiliation(s)
- Joseph P Lynch
- Division of Pulmonary, Critical Care Medicine, Allergy, and Clinical Immunology; Department of Medicine; The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Nina M Clark
- Division of Infectious Diseases, Department of Medicine, Loyola University Medical Center, Maywood, Illinois
| | - George G Zhanel
- Department of Medical Microbiology/Infectious Diseases, University of Manitoba, Max Rady College of Medicine, Winnipeg, Manitoba, Canada
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3
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Yamazaki T, Matsuo J. Mutation frequency of Escherichia coli isolated from river water: potential role in the development of antimicrobial resistance. Can J Microbiol 2021; 67:651-656. [PMID: 33756093 DOI: 10.1139/cjm-2020-0547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bacteria acquire genetic variations that help them to adapt to stressful environmental conditions, and these changes may be associated with the development of antimicrobial resistance. In this study, we investigated the mutation frequencies of 270 isolates of Escherichia coli from river water, which represents a relatively unstressful environment. As we predicted, mutation frequencies of the E. coli isolates ranged from <1 × 10-11 to 6.3 × 10-8 (median, 1.7 × 10-9), and a strong mutator (≥ 4 × 10-7) was not detected. To better understand the role of mutation frequency in the development of antimicrobial resistance, we assessed antimicrobial sensitivity after exposure of the E. coli isolates to subinhibitory concentrations of ciprofloxacin, as a surrogate for stress. We found that antimicrobial resistance increased in bacteria with a low mutation frequency after exposure, and the relative increase in antimicrobial resistance generally increased, depending on the mutation frequency. Thus, mutation frequency may contribute to the development of antimicrobial resistance of bacteria in natural environments.
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Affiliation(s)
- Tomohiro Yamazaki
- School of Medical Technology, Health Sciences University of Hokkaido, Ainosato 2-5, Kita-ku, Sapporo 002-8072, Japan.,School of Medical Technology, Health Sciences University of Hokkaido, Ainosato 2-5, Kita-ku, Sapporo 002-8072, Japan
| | - Junji Matsuo
- School of Medical Technology, Health Sciences University of Hokkaido, Ainosato 2-5, Kita-ku, Sapporo 002-8072, Japan.,School of Medical Technology, Health Sciences University of Hokkaido, Ainosato 2-5, Kita-ku, Sapporo 002-8072, Japan
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4
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Karakonstantis S, Saridakis I. Colistin heteroresistance in Acinetobacter spp.: systematic review and meta-analysis of the prevalence and discussion of the mechanisms and potential therapeutic implications. Int J Antimicrob Agents 2020; 56:106065. [PMID: 32599229 DOI: 10.1016/j.ijantimicag.2020.106065] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/30/2020] [Accepted: 06/20/2020] [Indexed: 01/29/2023]
Abstract
BACKGROUND Colistin is one of the few remaining options for carbapenem-resistant Acinetobacter baumannii (A. baumannii); however, emergence of resistance from heteroresistant populations is possible. This review aimed to systematically search and consolidate the literature on the prevalence, mechanisms and therapeutic implications of colistin heteroresistance in Acinetobacter spp. METHODS A systematic search was conducted in PubMed and Scopus. The pooled prevalence of colistin heteroresistance was calculated using meta-analysis of proportions with the Freeman-Tukey transformation and the random-effects (DerSimonian and Laird) method. RESULTS Based on 15 studies the prevalence of colistin heteroresistance was 33% (95% CI 16-53%) but considerable heterogeneity was observed (I2 = 96%, P < 0.001). Prior exposure to colistin was associated with a higher proportion of resistant subpopulations. Colistin heteroresistance may result from chromosomal mutations in resistant subpopulations (predominantly in PmrAB and lpx genes) resulting in lipopolysaccharide modification or loss, or overexpression of efflux pumps. No dosage scheme of colistin monotherapy can prevent the emergence of resistant subpopulations in vitro, but few studies have reported in vivo emergence of resistance from heteroresistant A. baumannii during treatment, and studies examining the correlation between heteroresistance and clinical/microbiological outcomes are lacking. Several colistin-based combinations have been shown in vitro to prevent the emergence of the resistant subpopulations but none have been translated so far into clinical benefit. Reasons for this discrepancy are discussed. CONCLUSIONS Colistin heteroresistance was common but highly variable between studies. The impact of colistin heteroresistance (frequency of emergent resistance during treatment and correlation with treatment outcomes) requires further study.
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Affiliation(s)
- Stamatis Karakonstantis
- School of Medicine, University of Crete, Heraklion, Crete, Greece; Internal Medicine Department, General Hospital of Heraklion Venizeleio, Heraklion, Crete, Greece.
| | - Ioannis Saridakis
- Internal Medicine Department, General Hospital of Heraklion Venizeleio, Heraklion, Crete, Greece
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5
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The fitness challenge of studying molecular adaptation. Biochem Soc Trans 2020; 47:1533-1542. [PMID: 31642877 DOI: 10.1042/bst20180626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/30/2019] [Accepted: 10/02/2019] [Indexed: 11/17/2022]
Abstract
Advances in bioinformatics and high-throughput genetic analysis increasingly allow us to predict the genetic basis of adaptive traits. These predictions can be tested and confirmed, but the molecular-level changes - i.e. the molecular adaptation - that link genetic differences to organism fitness remain generally unknown. In recent years, a series of studies have started to unpick the mechanisms of adaptation at the molecular level. In particular, this work has examined how changes in protein function, activity, and regulation cause improved organismal fitness. Key to addressing molecular adaptations is identifying systems and designing experiments that integrate changes in the genome, protein chemistry (molecular phenotype), and fitness. Knowledge of the molecular changes underpinning adaptations allow new insight into the constraints on, and repeatability of adaptations, and of the basis of non-additive interactions between adaptive mutations. Here we critically discuss a series of studies that examine the molecular-level adaptations that connect genetic changes and fitness.
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Sequence type-258 carbapenem-resistant Klebsiella pneumoniae isolates in which ceftazidime-avibactam resistance emerged are not hypermutators. Diagn Microbiol Infect Dis 2019; 96:114954. [PMID: 31864758 DOI: 10.1016/j.diagmicrobio.2019.114954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 11/02/2019] [Accepted: 11/06/2019] [Indexed: 11/21/2022]
Abstract
Ceftazidime-avibactam resistance among carbapenem-resistant Klebsiella pneumoniae at our hospital has emerged in sequence type (ST)-258, clade II isolates. We investigated hypermutability of ST258, clade II (n = 6) and clade I K. pneumoniae (n = 8) using a standard rifampin assay. Mutational frequencies were ≤10-7.1, indicating that isolates were not hypermutators. Mutational frequencies did not differ between clade II and I isolates. Ceftazidime-avibactam resistance among ST258, clade II K. pneumoniae is most likely a reflection of our hospital's ecology.
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7
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Rutten JP, Hogeweg P, Beslon G. Adapting the engine to the fuel: mutator populations can reduce the mutational load by reorganizing their genome structure. BMC Evol Biol 2019; 19:191. [PMID: 31627727 PMCID: PMC6800497 DOI: 10.1186/s12862-019-1507-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/02/2019] [Indexed: 11/24/2022] Open
Abstract
Background Mutators are common in bacterial populations, both in natural isolates and in the lab. The fate of these lineages, which mutation rate is increased up to 100 ×, has long been studied using population genetics models, showing that they can spread in a population following an environmental change. However in stable conditions, they suffer from the increased mutational load, hence being overcome by non-mutators. However, these results don’t take into account the fact that an elevated mutation rate can impact the genetic structure, hence changing the sensitivity of the population to mutations. Here we used Aevol, an in silico experimental evolution platform in which genomic structures are free to evolve, in order to study the fate of mutator populations evolving for a long time in constant conditions. Results Starting from wild-types that were pre-evolved for 300,000 generations, we let 100 mutator populations (point mutation rate ×100) evolve for 100,000 further generations in constant conditions. As expected all populations initially undergo a fitness loss. However, after that the mutator populations started to recover. Most populations ultimately recovered their ancestors fitness, and a significant fraction became even fitter than the non-mutator control clones that evolved in parallel. By analyzing the genomes of the mutators, we show that the fitness recovery is due to two mechanisms: i. an increase in robustness through compaction of the coding part of the mutator genomes, ii. an increase of the selection coefficient that decreases the mean-fitness of the population. Strikingly the latter is due to the accumulation of non-coding sequences in the mutators genomes. Conclusion Our results show that the mutational burden that is classically thought to be associated with mutator phenotype is escapable. On the long run mutators adapted their genomes and reshaped the distribution of mutation effects. Therewith the lineage is able to recover fitness even though the population still suffers the elevated mutation rate. Overall these results change our view of mutator dynamics: by being able to reduce the deleterious effect of the elevated mutation rate, mutator populations may be able to last for a very long time; A situation commonly observed in nature.
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Affiliation(s)
- Jacob Pieter Rutten
- Theoretical Biology and Bioinformatics group,Utrecht University, Padualaan 8, Utrecht, Netherlands.,Université de Lyon, INRIA, CNRS, INSA-Lyon, Beagle Team, LIRIS, UMR5205, Villeurbanne, 69601, France
| | - Paulien Hogeweg
- Theoretical Biology and Bioinformatics group,Utrecht University, Padualaan 8, Utrecht, Netherlands
| | - Guillaume Beslon
- Université de Lyon, INRIA, CNRS, INSA-Lyon, Beagle Team, LIRIS, UMR5205, Villeurbanne, 69601, France.
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8
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Hornsey M, Wareham DW. Effects of In vivo Emergent Tigecycline Resistance on the Pathogenic Potential of Acinetobacter baumannii. Sci Rep 2018. [PMID: 29523824 PMCID: PMC5844891 DOI: 10.1038/s41598-018-22549-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Multidrug-resistant lineages of Acinetobacter baumannii (MDRAB) are important nosocomial pathogens. As tigecycline remains active against most MDRAB we sought to investigate whether tigecycline resistance impacts biological fitness. The effects of treatment-emergent tigecycline resistance were investigated in vitro and in vivo using two pre- (AB210; W6976) and post-therapy (AB211; W7282) clinical pairs, recovered from individual patients, where tigecycline resistance was associated with up-regulated efflux activity. All isolates belonged to the same epidemic UK lineage. Significant differences were observed in end-point survival proportions between AB210 and AB211, but not between W6976 and W7282, using the Galleria mellonella infection model. Isolate AB211 outcompeted AB210 in vivo, in contrast to isolate W7282, which was outcompeted by its pre-therapy counterpart, W6972. Whole-genome sequencing of isolates W6976 and W7282 revealed a mutation in the adeABC regulatory gene, adeS in W7282; resulting in a Ser-8 → Arg substitution. Previous whole-genome comparison of AB210 and AB211 also identified a non-synonymous mutation in adeS, among several other lesions in genes involved in biofilm formation and DNA mismatch repair; consistent with the phenotypic differences described here. In conclusion, the differing effects on the wider phenotype were not predictable from the antibiograms or clonal lineage, despite a common mechanism of tigecycline resistance.
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Affiliation(s)
- Michael Hornsey
- Antimicrobial Research Group, Centre for Immunology and Infectious Disease, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University London, London, UK
| | - David W Wareham
- Antimicrobial Research Group, Centre for Immunology and Infectious Disease, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University London, London, UK. .,Division of Infection, Barts & The London NHS Trust, London, UK.
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9
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Graña-Miraglia L, Lozano LF, Velázquez C, Volkow-Fernández P, Pérez-Oseguera Á, Cevallos MA, Castillo-Ramírez S. Rapid Gene Turnover as a Significant Source of Genetic Variation in a Recently Seeded Population of a Healthcare-Associated Pathogen. Front Microbiol 2017; 8:1817. [PMID: 28979253 PMCID: PMC5611417 DOI: 10.3389/fmicb.2017.01817] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/06/2017] [Indexed: 12/11/2022] Open
Abstract
Genome sequencing has been useful to gain an understanding of bacterial evolution. It has been used for studying the phylogeography and/or the impact of mutation and recombination on bacterial populations. However, it has rarely been used to study gene turnover at microevolutionary scales. Here, we sequenced Mexican strains of the human pathogen Acinetobacter baumannii sampled from the same locale over a 3 year period to obtain insights into the microevolutionary dynamics of gene content variability. We found that the Mexican A. baumannii population was recently founded and has been emerging due to a rapid clonal expansion. Furthermore, we noticed that on average the Mexican strains differed from each other by over 300 genes and, notably, this gene content variation has accrued more frequently and faster than the accumulation of mutations. Moreover, due to its rapid pace, gene content variation reflects the phylogeny only at very short periods of time. Additionally, we found that the external branches of the phylogeny had almost 100 more genes than the internal branches. All in all, these results show that rapid gene turnover has been of paramount importance in producing genetic variation within this population and demonstrate the utility of genome sequencing to study alternative forms of genetic variation.
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Affiliation(s)
- Lucía Graña-Miraglia
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Luis F Lozano
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Consuelo Velázquez
- Departamento de Enfermedades Infecciosas, Instituto Nacional de CancerologíaMexico, Mexico
| | | | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
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10
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11
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Deiham B, Douraghi M, Adibhesami H, Yaseri M, Rahbar M. Screening of mutator phenotype in clinical strains of Acinetobacter baumannii. Microb Pathog 2017; 104:175-179. [PMID: 28111327 DOI: 10.1016/j.micpath.2017.01.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/12/2017] [Accepted: 01/18/2017] [Indexed: 11/30/2022]
Abstract
To our knowledge, no study has considered the growing colonies of A. baumannii in the inhibition zone of antibiotic disks as an indication of mutator. Here, we screened the mutator phenotype in a large series of clinical strains of A. baumannii. A collection of 300 strains were tested for antibiotic susceptibility and yielding colonies in the inhibition zone of antibiotic disks. The mutation frequency (MF) of strains was determined using rifampicin screen agar (300 μg/mL). Among strains tested, 180 had colonies in the inhibition zone of at least one or more than one (≤7) antibiotic. Sixty strains also generated mutant colonies on rifampicin screen agar with MF mean of 4.9 × 10-9. One strain was found with 59-fold (2.9 × 10-7) increase of MF than the mean value, only yielded colonies in the inhibition zone of imipenem, and classified as strong mutator or hypermutator. The MF ranged from 1 × 10-12 to 6.6 × 10-10 in remaining strains (n = 59), corresponded to non-mutator phenotype. There was a significant correlation between the number of colonies that grew in inhibition zone of amikacin disk and MF (P = 0.002). We showed that mutator phenotype emerged among clinical strains of A. baumannii as expected frequency in other bacterial species from non-chronic infections. This study revealed that wide screening of strains yielding colonies in the inhibition zone of antibiotics can be utilized to identify mutators. The mutant colonies need to be considered as a subpopulation of bacteria that may affect the interpretation of antibiotic susceptibility testing and consequently lead to treatment failure.
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Affiliation(s)
- Behnaz Deiham
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoumeh Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Habibeh Adibhesami
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Yaseri
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Rahbar
- Department of Microbiology, Reference Health Laboratories, Ministry of Health, Tehran, Iran
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12
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Mutation tendency of mutator Plasmodium berghei with proofreading-deficient DNA polymerase δ. Sci Rep 2016; 6:36971. [PMID: 27845384 PMCID: PMC5109483 DOI: 10.1038/srep36971] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/21/2016] [Indexed: 12/05/2022] Open
Abstract
In this study, we investigated the mutation tendency of a mutator rodent malaria parasite, Plasmodium berghei, with proofreading-deficient DNA polymerase δ. Wild-type and mutator parasites were maintained in mice for over 24 weeks, and the genome-wide accumulated mutations were determined by high-throughput sequencing. The mutator P. berghei had a significant preference for C/G to A/T substitutions; thus, its genome had a trend towards a higher AT content. The mutation rate was influenced by the sequence context, and mutations were markedly elevated at TCT. Some genes mutated repeatedly in replicate passage lines. In particular, knockout mutations of the AP2-G gene were frequent, which conferred strong growth advantages on parasites during the blood stage but at the cost of losing the ability to form gametocytes. This is the first report to demonstrate a biased mutation tendency in malaria parasites, and its results help to promote our basic understanding of Plasmodium genetics.
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McGann P, Bunin JL, Snesrud E, Singh S, Maybank R, Ong AC, Kwak YI, Seronello S, Clifford RJ, Hinkle M, Yamada S, Barnhill J, Lesho E. Real time application of whole genome sequencing for outbreak investigation - What is an achievable turnaround time? Diagn Microbiol Infect Dis 2016; 85:277-282. [PMID: 27185645 DOI: 10.1016/j.diagmicrobio.2016.04.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/30/2016] [Accepted: 04/27/2016] [Indexed: 12/20/2022]
Abstract
Whole genome sequencing (WGS) is increasingly employed in clinical settings, though few assessments of turnaround times (TAT) have been performed in real-time. In this study, WGS was used to investigate an unfolding outbreak of vancomycin resistant Enterococcus faecium (VRE) among 3 patients in the ICU of a tertiary care hospital. Including overnight culturing, a TAT of just 48.5 h for a comprehensive report was achievable using an Illumina Miseq benchtop sequencer. WGS revealed that isolates from patient 2 and 3 differed from that of patient 1 by a single nucleotide polymorphism (SNP), indicating nosocomial transmission. However, the unparalleled resolution provided by WGS suggested that nosocomial transmission involved two separate events from patient 1 to patient 2 and 3, and not a linear transmission suspected by the time line. Rapid TAT's are achievable using WGS in the clinical setting and can provide an unprecedented level of resolution for outbreak investigations.
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Affiliation(s)
- Patrick McGann
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Jessica L Bunin
- Department of Critical Care, Tripler Army Medical Center, Honolulu, HI, USA
| | - Erik Snesrud
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Seema Singh
- Department of Pathology, Tripler Army Medical Center, Honolulu, HI, USA
| | - Rosslyn Maybank
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Ana C Ong
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Yoon I Kwak
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Scott Seronello
- Department of Pathology, Tripler Army Medical Center, Honolulu, HI, USA
| | - Robert J Clifford
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Mary Hinkle
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Stephen Yamada
- Infectious Diseases Service, Tripler Army Medical Center, Honolulu, HI, USA
| | - Jason Barnhill
- Department of Pathology, Tripler Army Medical Center, Honolulu, HI, USA
| | - Emil Lesho
- Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD, USA
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