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Sivasankar S, Premnath MA, Boppe A, Grobusch MP, Jeyaraj S. Screening of MMV pandemic response and pathogen box compounds against pan-drug-resistant Klebsiella pneumoniae to identify potent inhibitory compounds. New Microbes New Infect 2023; 55:101193. [PMID: 38046897 PMCID: PMC10690571 DOI: 10.1016/j.nmni.2023.101193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 12/05/2023] Open
Abstract
Background The recent emergence of pan-drug-resistant (PDR) K. pneumoniae strains hinders the success rate of treatment procedures for patients. High mortality, extended duration of hospitalization with high costs is associated with such infections. Discovery and identification of new drugs are inevitable to combat PDR clinical pathogens. We aim to identify and evaluate new compounds in vitro against a PDR clinical K. pneumoniae isolate using compounds of Pathogen Box and Pandemic Response Box from Medicines for Malaria Venture (MMV). Methods The PDR strain was initially screened with the 601 compounds from both Boxes at 10 μM concentration. Formation of dormant cells against the drug activity was assessed using persister assay. MIC was determined for the drugs inhibiting PDR K. pneumoniae during initial screening. Results Five compounds were identified to inhibit the test strain. MMV1580854 (94.60 %), MMV1579788 (94.65 %), MMV1578574 (eravacycline; 93.13 %), MMV1578566 (epetraborole; 95.29 %) and MMV1578564 (96.32 %) were able to exhibit a higher percentage of growth inhibition. Persisters were found to be growing in a range from 104 to 107 CFU/ml. Minimum inhibitory concentrations (MIC) of all compounds were ≥ 2 μM except for MMV1579788, which had a MIC of ≥ 5 μM. Conclusion Five novel compounds were identified against the highly evolved pan-drug-resistant K. pneumoniae. Among the five, epetraborole andMMV1578564 were identified as highly potent based on the persister frequency and MICs. The pan-drug resistant clinical isolate used in this study was found to be acting differently from the reference or wild type strains against the test compounds in a previous study.
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Affiliation(s)
- Seshan Sivasankar
- PSG Center for Molecular Medicine and Therapeutics, PSG Institute of Medical Sciences and Research, Coimbatore, India
- PSG Center for Genetics and Molecular Biology, Off Avinashi Road, Coimbatore, India
| | - Mari Abinaya Premnath
- PSG Center for Molecular Medicine and Therapeutics, PSG Institute of Medical Sciences and Research, Coimbatore, India
- PSG Center for Genetics and Molecular Biology, Off Avinashi Road, Coimbatore, India
| | - Appalaraju Boppe
- Department of Microbiology, PSG Institute of Medical Sciences and Research, Coimbatore, India
| | - Martin Peter Grobusch
- Centre de Recherches Médicales de Lambaréné CERMEL, Hospital Albert Schweitzer, BP 242, Lambaréné, Gabon
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, Amsterdam Infection and Immunity, Amsterdam Public Health, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, the Netherlands
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Center for Infection Research (DZIF), Tubingen, Germany
- Masanga Medical Research Unit, Masanga, Sierra Leone
- Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Sankarganesh Jeyaraj
- PSG Center for Molecular Medicine and Therapeutics, PSG Institute of Medical Sciences and Research, Coimbatore, India
- PSG Center for Genetics and Molecular Biology, Off Avinashi Road, Coimbatore, India
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Detection of synergistic antimicrobial resistance mechanisms in clinical isolates of Pseudomonas aeruginosa from post-operative wound infections. Appl Microbiol Biotechnol 2021; 105:9321-9332. [PMID: 34797390 DOI: 10.1007/s00253-021-11680-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/20/2021] [Accepted: 11/02/2021] [Indexed: 12/11/2022]
Abstract
Infections caused by carbapenem-resistant Pseudomonas aeruginosa are life-threatening due to its synergistic resistance mechanisms resulting in the ineffectiveness of the used antimicrobials. This study aimed to characterize P. aeruginosa isolates for antimicrobial susceptibility, biofilm formation virulence genes, and molecular mechanisms responsible for resistance against various antimicrobials. Out of 700 samples, 91 isolates were confirmed as P. aeruginosa which were further classified into 19 non-multidrug-resistant (non-MDR), 7 multidrug-resistant (MDR), 19 extensively drug-resistant (XDR), and 8 pan drug-resistant (PDR) pulsotypes based on standard Kirby Bauer disc diffusion test and pulse field gel electrophoresis. In M9 minimal media, strong biofilms were formed by the XDR and PDR pulsotypes as compared to the non-MDR pulsotypes. The virulence genes, responsible for the worsening of wounds including LasB, plcH, toxA, and exoU, were detected among all MDR, XDR, and PDR pulsotypes. Carbapenemase activity was phenotypically detected in 45% pulsotypes and the responsible genes were found as blaGES (100%), blaVIM (58%), blaIMP (4%), and blaNDM (4%). Real-time polymerase chain reaction showed the concomitant use of multiple mechanisms such as oprD under-expression, enhanced efflux pump activity, and ampC overexpression in the resistant isolates. Polymyxin is found as the only class left with more than 80% susceptibility among the isolates which is an alarming situation suggesting appropriate measures to be taken including alternative therapies. KEY POINTS: • Multidrug-resistant P. aeruginosa isolates formed stronger biofilms in minimal media. • Only polymyxin antimicrobial was found effective against MDR P. aeruginosa isolates. • Under-expression of oprD and overexpression of ampC were found in resistant isolates.
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Wang Z, Yu F, Shen X, Li M. A Polyclonal Spread Emerged: Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Isolates from the Intensive Care Unit in a Chinese Tertiary Hospital. Pol J Microbiol 2021; 69:311-319. [PMID: 33574860 PMCID: PMC7810120 DOI: 10.33073/pjm-2020-034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/08/2020] [Accepted: 07/22/2020] [Indexed: 12/12/2022] Open
Abstract
Carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates often cause nosocomial infections with limited therapeutic options and spread rapidly worldwide. In this study, we revealed a polyclonal emergence of CRKP isolates from the intensive care unit in a Chinese tertiary hospital. We applied a series of methods including automated screening, antimicrobial susceptibility testing, the modified carbapenem inacti vation method (mCIM), PCR amplification, DNA sequencing, and multilocus sequence typing (MLST) to characterize 30 non-duplicated CRKP isolates along with the collection of the related medical records. The results showed the polyclonal spread of CRKP isolates belonged to ST722, ST1446, ST111, ST896, ST290, and ST11. Among them, ST722 and ST1446 were two novel types of K. pneumoniae, and ST896 isolate harboring blaKPC-2 was also found for the first time. Since the polyclonal spread of CRKP in the same ward is rare, the silent clonal evolution with the switching genotypes prompts us to stay alert for outbreaks caused by novel subclones.
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Affiliation(s)
- Zhengzheng Wang
- Department of Clinical Laboratory, Hwa Mei Hospital, University of Chinese Academy of Sciences, Ningbo, Zhejiang, China.,Ningbo Institute of Life and Health, University of Chinese Academy of Sciences, Ningbo, Zhejiang, China
| | - Fangyou Yu
- Department of Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaofei Shen
- Department of Respiratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Meilan Li
- Emergency Intensive Care Unit, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
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Yang SK, Yusoff K, Thomas W, Akseer R, Alhosani MS, Abushelaibi A, Lim SHE, Lai KS. Lavender essential oil induces oxidative stress which modifies the bacterial membrane permeability of carbapenemase producing Klebsiella pneumoniae. Sci Rep 2020; 10:819. [PMID: 31964900 PMCID: PMC6972767 DOI: 10.1038/s41598-019-55601-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 11/30/2019] [Indexed: 12/13/2022] Open
Abstract
Misuse of antibiotics in the clinical and agricultural sectors has caused the emergence of multidrug-resistant (MDR) Klebsiella pneumoniae which contributes a threat to human health. In this study, we assessed the feasibility of lavender essential oil (LVO) as an antimicrobial agent in combinatory therapy with meropenem in suppressing the growth of carbapenemase-producing K. pneumoniae (KPC-KP). Synergistic interactions between LVO and meropenem were detected, which significantly reduce the inhibitory concentration of both LVO and meropenem by 15 and 4-fold respectively. Comparative proteomic profiling identified a disruption in the bacterial membrane via oxidative stress that was indicated by loss of membrane and cytoplasmic proteins and the upregulation of oxidative regulators. As a proof of concept, zeta potential measurements showed a change in cell surface charge while outer membrane permeability measurement indicated an increase in membrane permeability following exposure to LVO. This was indicative of a disrupted outer membrane. Ethidium bromide influx/efflux assays demonstrated no significant efflux pump inhibition by LVO, and scanning electron microscopy revealed irregularities on the cell surface after exposure to LVO. Oxidative stress was also detected with increased level of ROS and lipid peroxidation in LVO-treated cells. In conclusion, our data suggest that LVO induced oxidative stress in K. pneumoniae which oxidizes the outer membrane, enabling the influx of generated ROS, LVO and meropenem into the bacterial cells, causing damage to the cells and eventually death.
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Affiliation(s)
- Shun-Kai Yang
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates
| | - Khatijah Yusoff
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Warren Thomas
- Perdana University-Royal College of Surgeons in Ireland School of Medicine, Perdana University, MAEPS Building, 43400, Serdang, Selangor, Malaysia
| | - Riaz Akseer
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates
| | - Maryam Sultan Alhosani
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates
| | - Aisha Abushelaibi
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates
| | - Swee-Hua-Erin Lim
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates. .,Perdana University-Royal College of Surgeons in Ireland School of Medicine, Perdana University, MAEPS Building, 43400, Serdang, Selangor, Malaysia.
| | - Kok-Song Lai
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates.
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Qian W, Sun Z, Wang T, Yang M, Liu M, Zhang J, Li Y. Antimicrobial activity of eugenol against carbapenem-resistant Klebsiella pneumoniae and its effect on biofilms. Microb Pathog 2019; 139:103924. [PMID: 31837416 DOI: 10.1016/j.micpath.2019.103924] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 01/01/2023]
Abstract
A preliminary study found that eugenol expressed an antibacterial activity against Klebsiella pneumoniae. However, the mechanism of action of eugenol against K. pneumoniae still remains unexplored. The aim of this study was to gain further insight into the antibacterial effect of eugenol against carbapenem-resistant Klebsiella pneumoniae (CRKP) and possible mode of action. Here, minimum inhibitory concentration (MIC) of eugenol against CRKP strains was determined using the agar dilution method. Moreover, variations in intracellular ATP concentration, intracellular pH (pHin), membrane potential and membrane integrity were measured to evaluate the effect of eugenol on cell membrane. Besides, changes in cell structure and biofilm formation of CRKP as well as biofilm-associated cell damage were determined using field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and confocal laser scanning microscopy (CLSM). Finally, gene expression of biofilm-related biosynthesis was investigated. The results showed that MICs of eugenol against four tested CRKP were 0.2 mg/mL. Eugenol damaged the cell membrane of CRKP, as evidenced by decreased intracellular ATP concentration, reduced pHin and cell membrane hyperpolarization, coupled with enhanced membrane permeability. Furthermore, eugenol compromised cell structure and induced loss of intracellular components of CRKP. Additionally, eugenol inhibited biofilm formation and inactivated biofilm CRKP cells. Finally, eugenol presented strong inhibitory effects on biofilm formation and biofilm-associated gene expression, and inactivated CRKP cells growing in biofilms. These findings suggest that eugenol exhibits antimicrobial effect against CRKP strains and could be potentially used to control CRKP-related infections.
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Affiliation(s)
- Weidong Qian
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China
| | - Zhaohuan Sun
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China
| | - Ting Wang
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China
| | - Min Yang
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China
| | - Miao Liu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China
| | - Jianing Zhang
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, PR China
| | - Yongdong Li
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo, 315010, PR China.
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Whole Genome Sequencing of Extended Spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae Isolated from Hospitalized Patients in KwaZulu-Natal, South Africa. Sci Rep 2019; 9:6266. [PMID: 31000772 PMCID: PMC6472517 DOI: 10.1038/s41598-019-42672-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 04/02/2019] [Indexed: 01/26/2023] Open
Abstract
Extended spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae remain a critical clinical concern worldwide. The aim of this study was to characterize ESBL-producing K. pneumoniae detected within and between two hospitals in uMgungundlovu district, South Africa, using whole genome sequencing (WGS). An observational period prevalence study on antibiotic-resistant ESKAPE (i.e. Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) bacteria was carried out in hospitalized patients during a two-month period in 2017. Rectal swabs and clinical specimens were collected from patients hospitalized and were screened for ESBL-producing, Gram-negative ESKAPE bacteria using cefotaxime-containing MacConkey agar and ESBL combination disk tests. Nine confirmed ESBL-K. pneumoniae isolated from six patients and two hospitals were whole genome sequenced using an Illumina MiSeq platform. Genome sequences were screened for presence of integrons, insertion sequences, plasmid replicons, CRISPR regions, resistance genes and virulence genes using different software tools. Of the 159 resistant Gram-negative isolates collected, 31 (19.50%) were ESBL-producers, of which, nine (29.03%) were ESBL-K. pneumoniae. The nine K. pneumoniae isolates harboured several β-lactamase genes, including blaCTX-M-15, blaTEM-1b, blaSHV-1, blaOXA-1 concomitantly with many other resistance genes e.g. acc(6')-lb-cr, aadAI6, oqxA and oqxB that confer resistance to aminoglycosides and/or fluoroquinolones, respectively. Three replicon plasmid types were detected in both clinical and carriage isolates, namely ColRNAI, IncFIB(K), IncF(II). Sequence type ST152 was confirmed in two patients (one carriage isolate detected on admission and one isolate implicated in infection) in one hospital. In contrast, ST983 was confirmed in a clinical and a carriage isolate of two patients in two different hospitals. Our data indicate introduction of ESBL-producing K. pneumoniae isolates into hospitals from the community. We also found evidence of nosocomial transmission within a hospital and transmission between different hospitals. The Clustered Regularly Interspaced Palindromic Repeats (CRISPR)-associated cas3 genes were further detected in two of the nine ESBL-KP isolates. This study showed that both district and tertiary hospital in uMgungundlovu District were reservoirs for several resistance determinants and highlighted the necessity to efficiently and routinely screen patients, particularly those receiving extensive antibiotic treatment and long-term hospitalization stay. It also reinforced the importance of infection, prevention and control measures to reduce the dissemination of antibiotic resistance within the hospital referral system in this district.
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Wise MG, Horvath E, Young K, Sahm DF, Kazmierczak KM. Global survey of Klebsiella pneumoniae major porins from ertapenem non-susceptible isolates lacking carbapenemases. J Med Microbiol 2018; 67:289-295. [DOI: 10.1099/jmm.0.000691] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mark G. Wise
- International Health Management Associates, Schaumburg, Illinois, USA
| | - Elizabeth Horvath
- International Health Management Associates, Schaumburg, Illinois, USA
| | | | - Daniel F. Sahm
- International Health Management Associates, Schaumburg, Illinois, USA
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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: 443] [Impact Index Per Article: 73.8] [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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Dsouza R, Pinto NA, Hwang I, Cho Y, Yong D, Choi J, Lee K, Chong Y. Panel strain of Klebsiella pneumoniae for beta-lactam antibiotic evaluation: their phenotypic and genotypic characterization. PeerJ 2017; 5:e2896. [PMID: 28133574 PMCID: PMC5251932 DOI: 10.7717/peerj.2896] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/10/2016] [Indexed: 01/21/2023] Open
Abstract
Klebsiella pneumoniae is responsible for numerous infections caused in hospitals, leading to mortality and morbidity. It has been evolving as a multi-drug resistant pathogen, acquiring multiple resistances such as such as horizontal gene transfer, transposon-mediated insertions or change in outer membrane permeability. Therefore, constant efforts are being carried out to control the infections using various antibiotic therapies. Considering the severity of the acquired resistance, we developed a panel of strains of K. pneumoniae expressing different resistance profiles such as high-level penicillinase and AmpC production, extended spectrum beta-lactamases and carbapenemases. Bacterial strains expressing different resistance phenotypes were collected and examined for resistance genes, mutations and porin alterations contributing to the detected phenotypes. Using the Massive parallel sequencing (MPS) technology we have constructed and genotypically characterized the panel strains to elucidate the multidrug resistance. These panel strains can be used in the clinical laboratory as standard reference strains. In addition, these strains could be significant in the field of pharmaceuticals for the antibiotic drug testing to verify its efficiency on pathogens expressing various resistances.
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Affiliation(s)
- Roshan Dsouza
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine , Seoul , South Korea
| | - Naina Adren Pinto
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, South Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, South Korea
| | - InSik Hwang
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, South Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, South Korea
| | | | - Dongeun Yong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine , Seoul , South Korea
| | - Jongrak Choi
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine , Seoul , South Korea
| | - Kyungwon Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine , Seoul , South Korea
| | - Yunsop Chong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine , Seoul , South Korea
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