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Lo CKF, Ritchie G, Bilawka J, Gowland L, Chorlton SD, Jang W, Matic N, Romney MG, Stefanovic A, Lowe CF. Evaluating the accuracy of the MBT Lipid Xtract Kit for assessing colistin resistance in comparison to broth microdilution. J Med Microbiol 2024; 73:001881. [PMID: 39222340 PMCID: PMC11368154 DOI: 10.1099/jmm.0.001881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 08/04/2024] [Indexed: 09/04/2024] Open
Abstract
Colistin resistance testing methods such as broth microdilution (BMD) are time-consuming and labour intensive for clinical laboratories. MBT Lipid Xtract Kit on MALDI Biotyper Sirius System (Bruker, Billerica, MA, USA) utilizes lipidomic analysis to identify specific cell wall modifications associated with colistin resistance. We compared MBT to BMD (ComASP Colistin, Liofilchem) across 36 Gram-negative isolates (non-resistant MIC ≤2 µg ml-1, resistant MIC ≥4 µg ml-1). All samples were tested twice on MBT with discrepant results repeated before assessing categorical agreement between MBT and BMD. 44.4% (16/36) of isolates were colistin resistant via BMD. MBT Lipid Xtract had 80.6% agreement (29/36) with BMD, with 5/7 discrepancies corrected to match upon repeat testing. There was 100% agreement for Escherichia coli isolates (n=16). The whole-genome sequencing was completed on the two discrepant Klebsiella pneumoniae isolates, with variants within colistin resistance-associated loci identified (MIC 0.5 µg ml-1: arnC S30T, pmrB T246A, lapB N212T, lpxM S253G, crrB Q287K and MIC >16 µg ml-1: arnC S30T, pmrB R90insRN, pmrB T246A, pmrA E57G, lpxM S253G). Further evaluation, particularly for non-E. coli, of MBT is required prior to implementation in clinical laboratories.
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Affiliation(s)
- Calvin Ka-Fung Lo
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gordon Ritchie
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Jennifer Bilawka
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Leah Gowland
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | | | - Willson Jang
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Nancy Matic
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Marc G. Romney
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Aleksandra Stefanovic
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Christopher F. Lowe
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Medical Microbiology and Virology, Providence Health Care, St. Paul’s Hospital, Vancouver, British Columbia, Canada
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Fang C, Zhou Z, Zhou M, Li J. Rapid detection of ceftriaxone-resistant Salmonella by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry combined with the ratio of optical density. Ann Clin Microbiol Antimicrob 2024; 23:70. [PMID: 39113073 PMCID: PMC11308677 DOI: 10.1186/s12941-024-00729-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 07/29/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND The increased resistance rate of Salmonella to third-generation cephalosporins represented by ceftriaxone (CRO) may result in the failure of the empirical use of third-generation cephalosporins for the treatment of Salmonella infection in children. The present study was conducted to evaluate a novel method for the rapid detection of CRO-resistant Salmonella (CRS). METHODS We introduced the concept of the ratio of optical density (ROD) with and without CRO and combined it with matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) to establish a new protocol for the rapid detection of CRS. RESULTS The optimal incubation time and CRO concentration determined by the model strain test were 2 h and 8 µg/ml, respectively. We then conducted confirmatory tests on 120 clinical strains. According to the receiver operating characteristic curve analysis, the ROD cutoff value for distinguishing CRS and non-CRS strains was 0.818 [area under the curve: 1.000; 95% confidence interval: 0.970-1.000; sensitivity: 100.00%; specificity: 100%; P < 10- 3]. CONCLUSIONS In conclusion, the protocol for the combined ROD and MALDI-TOF MS represents a rapid, accurate, and economical method for the detection of CRS.
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Affiliation(s)
- Chao Fang
- Department of Clinical Laboratory, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No. 3333 Binsheng road, Hangzhou, Zhejiang Province, China.
| | - Zheng Zhou
- Department of Clinical Laboratory, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No. 3333 Binsheng road, Hangzhou, Zhejiang Province, China
| | - Mingming Zhou
- Department of Clinical Laboratory, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No. 3333 Binsheng road, Hangzhou, Zhejiang Province, China
| | - Jianping Li
- Department of Clinical Laboratory, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No. 3333 Binsheng road, Hangzhou, Zhejiang Province, China
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Mosaffa F, Saffari F, Veisi M, Tadjrobehkar O. Some virulence genes are associated with antibiotic susceptibility in Enterobacter cloacae complex. BMC Infect Dis 2024; 24:711. [PMID: 39030479 PMCID: PMC11264964 DOI: 10.1186/s12879-024-09608-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 07/12/2024] [Indexed: 07/21/2024] Open
Abstract
BACKGROUND Enterobacter cloacae complex (ECC) including different species are isolated from different human clinical samples. ECC is armed by many different virulence genes (VGs) and they were also classified among ESKAPE group by WHO recently. The present study was designed to find probable association between VGs and antibiotic susceptibility in different ECC species. METHODS Forty-five Enterobacter isolates that were harvested from different clinical samples were classified in four different species. Seven VGs were screened by PCR technique and antibiotic susceptibility assessment was performed by disk-diffusion assay. RESULT Four Enterobacter species; Enterobacter cloacae (33.3%), Enterobacter hormaechei (55.6%), Enterobacter kobei (6.7%) and Enterobacter roggenkampii (4.4%) were detected. Minimum antibiotic resistance was against carbapenem agents and amikacin even in MDR isolates. 33.3% and 13.3% of isolates were MDR and XDR respectively. The rpoS (97.8%) and csgD (11.1%) showed maximum and minimum frequency respectively. Blood sample isolated were highly virulent but less resistant in comparison to the other sample isolates. The csgA, csgD and iutA genes were associated with cefepime sensitivity. CONCLUSION The fepA showed a predictory role for differentiating of E. hormaechei from other species. More evolved iron acquisition system in E. hormaechei was hypothesized. The fepA gene introduced as a suitable target for designing novel anti-virulence/antibiotic agents against E. hormaechei. Complementary studies on other VGs and ARGs and with bigger study population is recommended.
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Affiliation(s)
- Fatemeh Mosaffa
- Departement of Medical Microbiology (Bacteriology & Virology), Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Fereshteh Saffari
- Departement of Medical Microbiology (Bacteriology & Virology), Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Mahin Veisi
- Departement of Medical Microbiology (Bacteriology & Virology), Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Omid Tadjrobehkar
- Departement of Medical Microbiology (Bacteriology & Virology), Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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González-Gómez JP, Rodríguez-Arellano SN, Gomez-Gil B, Vergara-Jiménez MDJ, Chaidez C. Genomic and biological characterization of bacteriophages against Enterobacter cloacae, a high-priority pathogen. Virology 2024; 595:110100. [PMID: 38714025 DOI: 10.1016/j.virol.2024.110100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 04/20/2024] [Accepted: 05/02/2024] [Indexed: 05/09/2024]
Abstract
Enterobacter cloacae is a clinically significant pathogen due to its multi-resistance to antibiotics, presenting a challenge in the treatment of infections. As concerns over antibiotic resistance escalate, novel therapeutic approaches have been explored. Bacteriophages, characterized by their remarkable specificity and ability to self-replicate within target bacteria, are emerging as a promising alternative therapy. In this study, we isolated and partially characterized nine lytic bacteriophages targeting E. cloacae, with two selected for comprehensive genomic analysis based on their host range and bacteriolytic activity. All identified phages exhibited a narrow host range, demonstrated stability within a temperature range of 30-60 °C, displayed pH tolerance from 3 to 10, and showed an excellent bacteriolytic capacity for up to 18 h. Notably, the fully characterized phage genomes revealed an absence of lysogenic, virulence, or antibiotic-resistance genes, positioning them as promising candidates for therapeutic intervention against E. cloacae-related diseases. Nonetheless, translating this knowledge into practical therapeutic applications mandates a deeper understanding of bacteriophage interactions within complex biological environments.
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Affiliation(s)
- Jean Pierre González-Gómez
- Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (LANIIA), Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Carretera a Eldorado km 5.5, Campo El Diez, 80110, Culiacan, Sinaloa, Mexico
| | | | - Bruno Gomez-Gil
- Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Unidad Mazatlán en Acuicultura y Manejo Ambiental, AP 711, Mazatlan, Sinaloa, Mexico
| | | | - Cristobal Chaidez
- Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (LANIIA), Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Carretera a Eldorado km 5.5, Campo El Diez, 80110, Culiacan, Sinaloa, Mexico.
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2021-2022. MASS SPECTROMETRY REVIEWS 2024. [PMID: 38925550 DOI: 10.1002/mas.21873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/05/2024] [Accepted: 02/12/2024] [Indexed: 06/28/2024]
Abstract
The use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates is a well-established technique and this review is the 12th update of the original article published in 1999 and brings coverage of the literature to the end of 2022. As with previous review, this review also includes a few papers that describe methods appropriate to analysis by MALDI, such as sample preparation, even though the ionization method is not MALDI. The review follows the same format as previous reviews. It is divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of computer software for structural identification. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other general areas such as medicine, industrial processes, natural products and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. MALDI is still an ideal technique for carbohydrate analysis, particularly in its ability to produce single ions from each analyte and advancements in the technique and range of applications show little sign of diminishing.
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Smith RD, Zhan M, Zhang S, Leekha S, Harris A, Doi Y, Evans S, Kristie Johnson J, Ernst RK. Comparison of three rapid diagnostic tests for bloodstream infections using Benefit-risk Evaluation Framework (BED-FRAME). J Clin Microbiol 2024; 62:e0109623. [PMID: 38054730 PMCID: PMC10793330 DOI: 10.1128/jcm.01096-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/20/2023] [Indexed: 12/07/2023] Open
Abstract
Rapid diagnostic tests (RDTs) for bloodstream infections have the potential to reduce time to appropriate antimicrobial therapy and improve patient outcomes. Previously, an in-house, lipid-based, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) method, Fast Lipid Analysis Technique (FLAT MS), has shown promise as a rapid pathogen identification method. In this study, FLAT MS for direct from blood culture identification was evaluated and compared to FDA-cleared identification methods using the Benefit-risk Evaluation Framework (BED-FRAME) analysis. FLAT MS was evaluated and compared to Bruker Sepsityper and bioMérieux BioFire FilmArray BCID2 using results from a previous study. For this study, 301 positive blood cultures were collected from the University of Maryland Medical Center. The RDTs were compared by their sensitivities, time-to-results, hands-on time, and BED-FRAME analysis. The overall sensitivity of all platforms compared to culture results from monomicrobial-positive blood cultures was 88.3%. However, the three RDTs differed in their accuracy for identifying Gram-positive bacteria, Gram-negative bacteria, and yeast. Time-to-results for FLAT MS, Sepsityper, and BioFire BCID2 were all approximately one hour. Hands-on times for FLAT MS, Sepsityper, and BioFire BCID2 were 10 (±1.3), 40 (±2.8), and 5 (±0.25) minutes, respectively. BED-FRAME demonstrated that each RDT had utility at different pathogen prevalence and relative importance. BED-FRAME is a useful tool that can used to determine which RDT is best for a healthcare center.
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Affiliation(s)
- Richard D. Smith
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA
| | - Min Zhan
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Shanshan Zhang
- Biostatistics Center and the Department of Biostatistics and Bioinformatics, The George Washington University, Washington, D.C., USA
| | - Surbhi Leekha
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Anthony Harris
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yohei Doi
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Scott Evans
- Biostatistics Center and the Department of Biostatistics and Bioinformatics, The George Washington University, Washington, D.C., USA
| | - J. Kristie Johnson
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA
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Rubens RS, Arruda IDSA, Almeida RM, Nóbrega YKDM, Carneiro MDS, Dalmolin TV. Challenges in the Detection of Polymyxin Resistance: From Today to the Future. Microorganisms 2024; 12:101. [PMID: 38257928 PMCID: PMC10818861 DOI: 10.3390/microorganisms12010101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
Antimicrobial resistance is known to be one of the greatest global threats to human health, and is one of the main causes of death worldwide. In this scenario, polymyxins are last-resort antibiotics to treat infections caused by multidrug-resistant bacteria. Currently, the reference test to evaluate the susceptibility of isolates to polymyxins is the broth microdilution method; however, this technique has numerous complications and challenges for use in laboratory routines. Several phenotypic methods have been reported as being promising for implementation in routine diagnostics, including the BMD commercial test, rapid polymyxin NP test, polymyxin elution test, culture medium with polymyxins, and the Polymyxin Drop Test, which require materials for use in routines and must be easy to perform. Furthermore, Sensititre®, molecular tests, MALDI-TOF MS, and Raman spectroscopy present reliable results, but the equipment is not found in most microbiology laboratories. In this context, this review discusses the main laboratory methodologies that allow the detection of resistance to polymyxins, elucidating the challenges and perspectives.
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Affiliation(s)
- Rebeca Siqueira Rubens
- Laboratório de Microbiologia e Imunologia Clínica (LabMIC), Departamento de Farmácia, Faculdade de Ciências da Saúde, Universidade de Brasília (UnB), Brasília 70910-900, DF, Brazil; (R.S.R.); (I.d.S.A.A.); (R.M.A.); (Y.K.d.M.N.)
| | - Isabel de Souza Andrade Arruda
- Laboratório de Microbiologia e Imunologia Clínica (LabMIC), Departamento de Farmácia, Faculdade de Ciências da Saúde, Universidade de Brasília (UnB), Brasília 70910-900, DF, Brazil; (R.S.R.); (I.d.S.A.A.); (R.M.A.); (Y.K.d.M.N.)
| | - Rosane Mansan Almeida
- Laboratório de Microbiologia e Imunologia Clínica (LabMIC), Departamento de Farmácia, Faculdade de Ciências da Saúde, Universidade de Brasília (UnB), Brasília 70910-900, DF, Brazil; (R.S.R.); (I.d.S.A.A.); (R.M.A.); (Y.K.d.M.N.)
| | - Yanna Karla de Medeiros Nóbrega
- Laboratório de Microbiologia e Imunologia Clínica (LabMIC), Departamento de Farmácia, Faculdade de Ciências da Saúde, Universidade de Brasília (UnB), Brasília 70910-900, DF, Brazil; (R.S.R.); (I.d.S.A.A.); (R.M.A.); (Y.K.d.M.N.)
| | | | - Tanise Vendruscolo Dalmolin
- Laboratório de Microbiologia e Imunologia Clínica (LabMIC), Departamento de Farmácia, Faculdade de Ciências da Saúde, Universidade de Brasília (UnB), Brasília 70910-900, DF, Brazil; (R.S.R.); (I.d.S.A.A.); (R.M.A.); (Y.K.d.M.N.)
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Rogga V, Kosalec I. Untying the anchor for the lipopolysaccharide: lipid A structural modification systems offer diagnostic and therapeutic options to tackle polymyxin resistance. Arh Hig Rada Toksikol 2023; 74:145-166. [PMID: 37791675 PMCID: PMC10549895 DOI: 10.2478/aiht-2023-74-3717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/01/2023] [Accepted: 07/01/2023] [Indexed: 10/05/2023] Open
Abstract
Polymyxin antibiotics are the last resort for treating patients in intensive care units infected with multiple-resistant Gram-negative bacteria. Due to their polycationic structure, their mode of action is based on an ionic interaction with the negatively charged lipid A portion of the lipopolysaccharide (LPS). The most prevalent polymyxin resistance mechanisms involve covalent modifications of lipid A: addition of the cationic sugar 4-amino-L-arabinose (L-Ara4N) and/or phosphoethanolamine (pEtN). The modified structure of lipid A has a lower net negative charge, leading to the repulsion of polymyxins and bacterial resistance to membrane disruption. Genes encoding the enzymatic systems involved in these modifications can be transferred either through chromosomes or mobile genetic elements. Therefore, new approaches to resistance diagnostics have been developed. On another note, interfering with these enzymatic systems might offer new therapeutic targets for drug discovery. This literature review focuses on diagnostic approaches based on structural changes in lipid A and on the therapeutic potential of molecules interfering with these changes.
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Affiliation(s)
- Vanessa Rogga
- University of Zagreb Faculty of Pharmacy and Biochemistry, Department of Microbiology, Zagreb, Croatia
| | - Ivan Kosalec
- University of Zagreb Faculty of Pharmacy and Biochemistry, Department of Microbiology, Zagreb, Croatia
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Lakshmanan D, Ramasamy D, Subramanyam V, Saravanan SK. Mobile colistin resistance (mcr) genes and recent developments in colistin resistance detection. Lett Appl Microbiol 2023; 76:ovad102. [PMID: 37673673 DOI: 10.1093/lambio/ovad102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/17/2023] [Accepted: 09/05/2023] [Indexed: 09/08/2023]
Abstract
The peptide antibiotic colistin has been reserved as a last resort antibiotic treatment option for cases where other antibiotics including carbapenems have failed. Recent emergence of colistin resistance and discovery of mobile colistin resistance (mcr) genes, which encode the cell wall modifying phosphoethanolamine transferase enzyme, complicates the issue. The mcr genes have been associated with conjugative plasmids and can be horizontally transferred between different bacterial species. The global spread of mcr genes has been extensively documented and this warrants surveillance of the resistance genes in the community. However, susceptibility testing of colistin is fraught with practical challenges owing to the chemical nature of the drug and multiple mechanisms of resistance. Although broth microdilution is the current gold standard for colistin susceptibility testing, the method poses technical challenges. Hence, alternative detection methods for screening colistin resistance are the need of the hour. Several methods have been studied in the recent times to address this issue. In this review, we discuss some of the recent developments in the detection of colistin resistance.
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Affiliation(s)
- Divya Lakshmanan
- Mahatma Gandhi Medical Advanced Research Institute (MGMARI), Sri Balaji Vidyapeeth (Deemed-to-be-University), Pillayarkuppam, Pondicherry 607042, India
| | - Dhamodharan Ramasamy
- Mahatma Gandhi Medical Advanced Research Institute (MGMARI), Sri Balaji Vidyapeeth (Deemed-to-be-University), Pillayarkuppam, Pondicherry 607042, India
| | - Veni Subramanyam
- Mahatma Gandhi Medical Advanced Research Institute (MGMARI), Sri Balaji Vidyapeeth (Deemed-to-be-University), Pillayarkuppam, Pondicherry 607042, India
| | - Suresh Kumar Saravanan
- Mahatma Gandhi Medical Preclinical Research Centre (MGMPRC), Sri Balaji Vidyapeeth (Deemed-to-be-University), Pillayarkuppam, Pondicherry 607402, India
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Pětrošová H, Mikhael A, Culos S, Giraud-Gatineau A, Gomez AM, Sherman ME, Ernst RK, Cameron CE, Picardeau M, Goodlett DR. Lipid A structural diversity among members of the genus Leptospira. Front Microbiol 2023; 14:1181034. [PMID: 37303810 PMCID: PMC10248169 DOI: 10.3389/fmicb.2023.1181034] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Lipid A is the hydrophobic component of bacterial lipopolysaccharide and an activator of the host immune system. Bacteria modify their lipid A structure to adapt to the surrounding environment and, in some cases, to evade recognition by host immune cells. In this study, lipid A structural diversity within the Leptospira genus was explored. The individual Leptospira species have dramatically different pathogenic potential that ranges from non-infectious to life-threatening disease (leptospirosis). Ten distinct lipid A profiles, denoted L1-L10, were discovered across 31 Leptospira reference species, laying a foundation for lipid A-based molecular typing. Tandem MS analysis revealed structural features of Leptospira membrane lipids that might alter recognition of its lipid A by the host innate immune receptors. Results of this study will aid development of strategies to improve diagnosis and surveillance of leptospirosis, as well as guide functional studies on Leptospira lipid A activity.
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Affiliation(s)
- Helena Pětrošová
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- University of Victoria Genome British Columbia Proteomics Center, University of Victoria, Victoria, BC, Canada
| | - Abanoub Mikhael
- University of Victoria Genome British Columbia Proteomics Center, University of Victoria, Victoria, BC, Canada
| | - Sophie Culos
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | | | - Alloysius M. Gomez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Matthew E. Sherman
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States
| | - Caroline E. Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, WA, United States
| | - Mathieu Picardeau
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Biology of Spirochetes Unit, Paris, France
| | - David R. Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- University of Victoria Genome British Columbia Proteomics Center, University of Victoria, Victoria, BC, Canada
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Yang H, Smith RD, Sumner KP, Goodlett DR, Johnson JK, Ernst RK. A Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Direct-from-Urine-Specimen Diagnostic for Gram-Negative Pathogens. Microbiol Spectr 2022; 10:e0373022. [PMID: 36255333 PMCID: PMC9769899 DOI: 10.1128/spectrum.03730-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 01/10/2023] Open
Abstract
Urinary tract infections (UTIs) pose a major public health burden. The vast majority of UTIs are caused by Gram-negative bacteria. Current culture-based pathogen identification methods may require up to 24 to 48 h of incubation. In this study, we developed and evaluated a method for Gram-negative pathogen identification direct from urine, without culture, via matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in approximately 1 h. Urine samples were collected (n = 137) from the University of Maryland Medical Center clinical microbiology laboratory. To identify bacteria direct from urine, two methods were evaluated. First, 1 μL of urine was directly spotted onto the MALDI target plate, and second, 1 mL of urine was centrifuged at 8,000 rpm for 5 min before processing using the fast lipid analysis technique (FLAT). Mass spectra were acquired on the Bruker MALDI Biotyper sirius system in the negative-ion mode. Results were compared to those of standard culture methods. When 1 μL of urine was directly spotted, positive agreement was 81.5% (101/124) and, after centrifugation, 94.4% (117/124) relative to that of standard culture methods. Negative agreement for both methods was 100% (13/13). The time to results for both of the specimen preparation methods using the FLAT extraction protocol was approximately 1 h, with minimal hands-on time required (<5 min). The ability to rapidly identify pathogens directly from urine, without the need for culture, allows for faster turnaround times and, potentially, improved patient outcomes. Overall, the FLAT extraction protocol, in combination with lipid A identification, provides a reproducible and accurate method to rapidly identify urinary pathogens. IMPORTANCE This study describes and evaluates a direct-from-urine extraction method that allows identification of Gram-negative bacteria via MALDI-TOF MS within 1 h. Currently, identification of urinary pathogens requires 24 h of culture prior to identification. While this method may not replace culture, we demonstrate its utility in screening for common urinary pathogens. By providing identifications in under 1 h, clinicians can potentially treat patients sooner with more-targeted antimicrobial therapy. In turn, earlier treatment can improve patient outcome and antimicrobial stewardship. Furthermore, MADLI-TOF MS is a readily available, easy-to-use diagnostic tool in clinical laboratories, making implementation of this method possible.
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Affiliation(s)
- Hyojik Yang
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
| | - Richard D. Smith
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Department of Pathology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Kylie P. Sumner
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - David R. Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
- International Centre for Cancer Vaccine Science, University of Gdansk, Gdansk, Poland
| | - J. Kristie Johnson
- Department of Pathology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
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Sherman ME, Smith RD, Gardner FM, Goodlett DR, Ernst RK. A Sensitive GC-MS Method for Quantitation of Lipid A Backbone Components and Terminal Phosphate Modifications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:2301-2309. [PMID: 36326685 PMCID: PMC9933694 DOI: 10.1021/jasms.2c00266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Lipid A, the hydrophobic anchor of lipopolysaccharide (LPS) present in the outer membrane of Gram-negative bacteria, serves as a target for cationic antimicrobial peptides, such as polymyxins. Membrane stress from polymyxins results in activation of two-component regulatory systems that produce lipid A modifying enzymes. These enzymes add neutral moieties, such as aminoarabinose (AraN) and ethanolamine (EtN) to lipid A terminal phosphates that mask the phosphate's negative charge and inhibit electrostatic interaction with the cationic polymyxins. Currently, these modifications may be detected by MALDI-TOF MS; however, this analysis is only semiquantitative. Herein we describe a GC-MS method to quantitate lipid A backbone components, glucosamine (GlcN) and inorganic phosphate (Pi), along with terminal phosphate modifications AraN and EtN. In this assay, lipid A is isolated from Gram-negative bacterial samples, hydrolyzed into its individual moieties, and derivatized via methoximation followed by silylation prior to analysis via GC-MS. Changes in AraN and EtN quantity were characterized using a variety of regulatory mutants of Salmonella, revealing differences that were not detected using MALDI-TOF MS analysis. Additionally, an increase in the abundance of AraN and EtN modifications were observed when resistant Enterobacter and Escherichia coli strains were grown in the presence of colistin (polymyxin E). Lastly, increased levels of Pi were found in bisphosphorylated lipid A compared to monophosphorylated lipid A samples. Because lipid A modifications serve as indicators of polymyxin resistance in Gram-negative bacteria, this method provides the capacity to monitor polymyxin resistance by quantification of lipid A modification using GC-MS.
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Affiliation(s)
- Matthew E Sherman
- Department of Microbial Pathogenesis, University of Maryland─Baltimore, Baltimore, Maryland 21201, United States
| | - Richard D Smith
- Department of Microbial Pathogenesis, University of Maryland─Baltimore, Baltimore, Maryland 21201, United States
| | - Francesca M Gardner
- Department of Microbial Pathogenesis, University of Maryland─Baltimore, Baltimore, Maryland 21201, United States
| | - David R Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- University of Gdansk, International Centre for Cancer Vaccine Science, Gdansk, 80-210, Poland
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland─Baltimore, Baltimore, Maryland 21201, United States
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Zhang C, Sun L, Wang D, Li Y, Zhang L, Wang L, Peng J. Advances in antimicrobial resistance testing. Adv Clin Chem 2022; 111:1-68. [DOI: 10.1016/bs.acc.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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