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Khan K, Jalal K, Uddin R. Pangenome diversification and resistance gene characterization in Salmonella Typhi prioritized RfaJ as a significant therapeutic marker. J Genet Eng Biotechnol 2023; 21:125. [PMID: 37975995 PMCID: PMC10656401 DOI: 10.1186/s43141-023-00591-w] [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: 07/21/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND Salmonella Typhi stands as the etiological agent responsible for the onset of human typhoid fever. The pressing demand for innovative therapeutic targets against S. Typhi is underscored by the escalating prevalence of this pathogen and the severe nature of its infections. Consequently, this study employs pangenome analysis to scrutinize 119 S. Typhi-resistant strains, aiming to identify the most promising therapeutic targets originating from its core genome. RESULTS Subtractive genomics was employed to systematically eliminate non-homologous (n=1147), essential (n=551), drug-like (n=80), and pathogenicity-related (n=18) proteins from the initial pool of 3351 core genome proteins. Consequently, lipopolysaccharide 1,2-glucosyltransferase RfaJ was designated as the optimal pharmacological target due to its potential versatility. Furthermore, a compendium of 9000 FDA-approved compounds was repurposed for evaluation against the RfaJ drug target, with the specific intent of prioritizing novel, high-potency therapeutic candidates for combating S. Typhi. Ultimately, four compounds, namely DB00549 (Zafirlukast), DB15637 (Fluzoparib), DB15688 (Zavegepant), and DB12411 (Bemcentinib), were singled out as potential inhibitors based on the ligand-protein binding affinity (indicated by the lowest anticipated binding energy) and the overall stability of these compounds. Notably, molecular dynamics simulations, conducted over a 50 nanosecond interval, convincingly demonstrated the stability of these compounds in the context of the RfaJ protein. CONCLUSION In summary, the present findings hold significant promise as an initial stride in the broader drug discovery endeavor against S. Typhi infections. However, the experimental validation of the identified drug target and drug candidate is further required to increase the effectiveness of the applied methodology.
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Affiliation(s)
- Kanwal Khan
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Khurshid Jalal
- HEJ Research Institute of Chemistry International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Reaz Uddin
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.
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Mondal P, Halder P, Mallick B, Bhaumik S, Koley H, Dutta S, Dutta M. Controlling the bacterial load of Salmonella Typhi in an experimental mouse model by a lytic Salmonella phage STWB21: a phage therapy approach. BMC Microbiol 2023; 23:324. [PMID: 37924001 PMCID: PMC10623789 DOI: 10.1186/s12866-023-03040-3] [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: 07/21/2023] [Accepted: 10/03/2023] [Indexed: 11/06/2023] Open
Abstract
BACKGROUND Salmonella enterica serotype Typhi is one of the major pathogens causing typhoid fever and a public health burden worldwide. Recently, the increasing number of multidrug-resistant strains of Salmonella spp. has made this utmost necessary to consider bacteriophages as a potential alternative to antibiotics for S. Typhi infection treatment. Salmonella phage STWB21, isolated from environmental water, has earlier been reported to be effective as a safe biocontrol agent by our group. In this study, we evaluated the efficacy of phage STWB21 in reducing the burden of salmonellosis in a mammalian host by inhibiting Salmonella Typhi invasion into the liver and spleen tissue. RESULTS Phage treatment significantly improved the survival percentage of infected mice. This study also demonstrated that oral administration of phage treatment could be beneficial in both preventive and therapeutic treatment of salmonellosis caused by S. Typhi. Altogether the result showed that the phage treatment could control tissue inflammation in mice before and after Salmonella infection. CONCLUSIONS To the best of our knowledge, this is the first report of phage therapy in a mouse model against a clinically isolated Salmonella Typhi strain that includes direct visualization of histopathology and ultrathin section microscopy images from the liver and spleen sections.
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Affiliation(s)
- Payel Mondal
- Division of Electron Microscopy, ICMR-National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, 700010, Kolkata, West Bengal, India
| | - Prolay Halder
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, 700010, Kolkata, West Bengal, India
| | - Bani Mallick
- Division of Electron Microscopy, ICMR-National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, 700010, Kolkata, West Bengal, India
| | - Subhadip Bhaumik
- University Science Instrumentation Centre, The University of Burdwan, Golapbag, Burdwan, 713104, West Bengal, India
| | - Hemanta Koley
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, 700010, Kolkata, West Bengal, India
| | - Shanta Dutta
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, 700010, Kolkata, West Bengal, India
| | - Moumita Dutta
- Division of Electron Microscopy, ICMR-National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme XM, Beliaghata, 700010, Kolkata, West Bengal, India.
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Ain Q, Tahir M, Sadaqat A, Ayub A, Awan AB, Wajid M, Ali A, Iqbal M, Haque A, Sarwar Y. First Detection of Extensively Drug-Resistant Salmonella Typhi Isolates Harboring VIM and GES Genes for Carbapenem Resistance from Faisalabad, Pakistan. Microb Drug Resist 2022; 28:1087-1098. [DOI: 10.1089/mdr.2022.0094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Quratul Ain
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Mahnoor Tahir
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Amna Sadaqat
- Pediatric Medicine Unit, Allied Hospital, Faisalabad, Pakistan
| | - Ambreen Ayub
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Asad Bashir Awan
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Muhammad Wajid
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Aamir Ali
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Mazhar Iqbal
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
| | - Abdul Haque
- Akhuwat Faisalabad Institute for Research in Science and Technology, Faisalabad, Pakistan
| | - Yasra Sarwar
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
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Al-Rashdi A, Kumar R, Al-Bulushi M, Abri SA, Al-Jardani A. Genomic analysis of the first cases of extensively drug-resistant, travel-related Salmonella enterica serovar Typhi in Oman. IJID REGIONS 2021; 1:135-141. [PMID: 35757821 PMCID: PMC9216381 DOI: 10.1016/j.ijregi.2021.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/05/2021] [Accepted: 10/25/2021] [Indexed: 11/28/2022]
Abstract
XDR S. Typhi is spreading widely to different countries, and has emerged in Oman Surveillance programs in Oman have detected these cases, allowing prompt treatment The WGS method has played a major role in characterizing XDR S. Typhi
Objectives To highlight the importance of molecular testing in characterizing extensively drug-resistant (XDR) Salmonella Typhi (S. Typhi), and linking it to the current outbreak in Sindh, Pakistan. Methods Our study reports three travel-related typhoid fever cases caused by XDR S. Typhi that presented between January 2019 and August 2019. Antimicrobial susceptibility and genotyping with pulse-field gel electrophoresis (PFGE) were carried out. Whole-genome sequencing (WGS) was performed to characterize the genomic clonality in relation to the emerging outbreak of S. Typhi in Sindh, Pakistan, and to study the molecular resistance profiles. Results Laboratory testing revealed resistance to all first-line antibiotics (i.e ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole), as well as to quinolones and third-generation cephalosporins, leading to a change in the patients’ therapy to the use of carbapenems. Classical MLST (cMLST) revealed that the strains were of sequence type 1 (ST1) and the core genome sequence (cgWGS) analysis closely clustered our strains with internationally reported strains from Pakistan, India, and the UK. The strains were found to carry a blaCTX-15 gene-harbouring IncY plasmid, which encodes resistance to ceftriaxone. Conclusions Our report alerts clinicians to the use of appropriate empirical treatments in such scenarios, and highlights the significance of the global spread of XDR S. Typhi.
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Affiliation(s)
- Azza Al-Rashdi
- Central Public Health Laboratories, DGDSC, Ministry of Health, Muscat, Oman
- Corresponding author: Azza Al-Rashdi, Central Public Health Laboratories, Ministry of Health, Al-Mujamma Street, Bait Al-Falaj Darsait, P.O. Box 393, Postal Code 100, Muscat, Oman, Tel: 00968 99814093.
| | - Rajesh Kumar
- Central Public Health Laboratories, DGDSC, Ministry of Health, Muscat, Oman
| | - Mohamed Al-Bulushi
- Central Public Health Laboratories, DGDSC, Ministry of Health, Muscat, Oman
| | - Seif Al Abri
- Directorate General of Disease Surveillance and Control, Ministry of Health, Muscat, Oman
| | - Amina Al-Jardani
- Central Public Health Laboratories, DGDSC, Ministry of Health, Muscat, Oman
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Saleem K, Zafar S, Rashid A. Antimicrobial sensitivity patterns of enteric fever in Pakistan: a comparison of years 2009 and 2019. J R Coll Physicians Edinb 2021; 51:129-132. [PMID: 34131667 DOI: 10.4997/jrcpe.2021.206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Pakistan is one of the endemic regions for typhoid fever and paratyphoid fever. This study aimed to identify the evolving antimicrobial sensitivity patterns of Salmonella species causing enteric fever and its implications on the clinical prescribing of antimicrobials. METHODS This was a retrospective descriptive study conducted at a university hospital. Antimicrobial resistance was defined in terms of non-resistant, multidrug resistant (MDR) and extended drug resistant (XDR) as per WHO guidance. Data were collected from the years 2009 and 2019. Chi squared was applied to test for statistical significance (p < 0.05). RESULTS A total of 200 patients (100 from 2009 and 100 from 2019) were included in the study. Non-resistant enteric fever cases reduced from 100% in 2009 to 44% in 2019, whereas the MDR and XDR enteric fever cases increased to 16% and 40%, respectively (p < 0.05). Cross tabulation carried out for individual drugs showed an independent rise in the sensitivities of individual first-line antimicrobials. CONCLUSION Antimicrobial resistant enteric fever has become a big challenge for Pakistan. The choice of antibiotic prescription has narrowed down to broader spectrum antimicrobials making it difficult to treat, leading to increased morbidity and mortality.
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Affiliation(s)
- Khurram Saleem
- Department of Medicine, University College of Medicine, The University of Lahore Teaching Hospital, Pakistan
| | - Sana Zafar
- Department of Acute Medicine, University Hospital of Coventry and Warwickshire NHS Trust, 279 Ansty Road, Coventry CV2 3FL, UK,
| | - Aqeela Rashid
- Department of Medicine, University College of Medicine, The University of Lahore Teaching Hospital, Pakistan
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Rasheed F, Saeed M, Alikhan NF, Baker D, Khurshid M, Ainsworth EV, Turner AK, Imran AA, Rasool MH, Saqalein M, Nisar MA, Fayyaz ur Rehman M, Wain J, Yasir M, Langridge GC, Ikram A. Emergence of Resistance to Fluoroquinolones and Third-Generation Cephalosporins in Salmonella Typhi in Lahore, Pakistan. Microorganisms 2020; 8:microorganisms8091336. [PMID: 32883020 PMCID: PMC7564241 DOI: 10.3390/microorganisms8091336] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/26/2022] Open
Abstract
Extensively drug-resistant (XDR) Salmonella Typhi has been reported in Sindh province of Pakistan since 2016. The potential for further spread is of serious concern as remaining treatment options are severely limited. We report the phenotypic and genotypic characterization of 27 XDR S. Typhi isolated from patients attending Jinnah Hospital, Lahore, Pakistan. Isolates were identified by biochemical profiling; antimicrobial susceptibility was determined by a modified Kirby–Bauer method. These findings were confirmed using Illumina whole genome nucleotide sequence data. All sequences were compared to the outbreak strain from Southern Pakistan and typed using the S. Typhi genotyping scheme. All isolates were confirmed by a sequence analysis to harbor an IncY plasmid and the CTX-M-15 ceftriaxone resistance determinant. All isolates were of the same genotypic background as the outbreak strain from Sindh province. We report the first emergence of XDR S. Typhi in Punjab province of Pakistan confirmed by whole genome sequencing.
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Affiliation(s)
- Farhan Rasheed
- Allama Iqbal Medical College & Jinnah Hospital (AIMC&JHL), Lahore 54000, Pakistan;
- Correspondence: (F.R.); (M.Y.)
| | - Muhammad Saeed
- Department of Microbiology, Government College University, Faisalabad 38000, Pakistan; (M.S.); (M.K.); (M.H.R.); (M.S.); (M.A.N.)
| | - Nabil-Fareed Alikhan
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
| | - David Baker
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
| | - Mohsin Khurshid
- Department of Microbiology, Government College University, Faisalabad 38000, Pakistan; (M.S.); (M.K.); (M.H.R.); (M.S.); (M.A.N.)
| | - Emma V. Ainsworth
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
| | - A. Keith Turner
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
| | - Ambereen Anwar Imran
- Allama Iqbal Medical College & Jinnah Hospital (AIMC&JHL), Lahore 54000, Pakistan;
| | - Muhammad Hidayat Rasool
- Department of Microbiology, Government College University, Faisalabad 38000, Pakistan; (M.S.); (M.K.); (M.H.R.); (M.S.); (M.A.N.)
| | - Muhammad Saqalein
- Department of Microbiology, Government College University, Faisalabad 38000, Pakistan; (M.S.); (M.K.); (M.H.R.); (M.S.); (M.A.N.)
| | - Muhammad Atif Nisar
- Department of Microbiology, Government College University, Faisalabad 38000, Pakistan; (M.S.); (M.K.); (M.H.R.); (M.S.); (M.A.N.)
| | | | - John Wain
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Muhammad Yasir
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
- Correspondence: (F.R.); (M.Y.)
| | - Gemma C. Langridge
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UK; (N.-F.A.); (D.B.); (E.V.A.); (A.K.T.); (J.W.); (G.C.L.)
| | - Aamer Ikram
- National Institute of Health, Islamabad 45710, Pakistan;
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Turner AK, Eckert SE, Turner DJ, Yasir M, Webber MA, Charles IG, Parkhill J, Wain J. A whole-genome screen identifies Salmonella enterica serovar Typhi genes involved in fluoroquinolone susceptibility. J Antimicrob Chemother 2020; 75:2516-2525. [PMID: 32514543 PMCID: PMC7443733 DOI: 10.1093/jac/dkaa204] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/31/2020] [Accepted: 04/21/2020] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVES A whole-genome screen at sub-gene resolution was performed to identify candidate loci that contribute to enhanced or diminished ciprofloxacin susceptibility in Salmonella enterica serovar Typhi. METHODS A pool of over 1 million transposon insertion mutants of an S. Typhi Ty2 derivative were grown in a sub-MIC concentration of ciprofloxacin, or without ciprofloxacin. Transposon-directed insertion site sequencing (TraDIS) identified relative differences between the mutants that grew following the ciprofloxacin treatment compared with the untreated mutant pool, thereby indicating which mutations contribute to gain or loss of ciprofloxacin susceptibility. RESULTS Approximately 88% of the S. Typhi strain's 4895 annotated genes were assayed, and at least 116 were identified as contributing to gain or loss of ciprofloxacin susceptibility. Many of the identified genes are known to influence susceptibility to ciprofloxacin, thereby providing method validation. Genes were identified that were not known previously to be involved in susceptibility, and some of these had no previously known phenotype. Susceptibility to ciprofloxacin was enhanced by insertion mutations in genes coding for efflux, other surface-associated functions, DNA repair and expression regulation, including phoP, barA and marA. Insertion mutations that diminished susceptibility were predominantly in genes coding for surface polysaccharide biosynthesis and regulatory genes, including slyA, emrR, envZ and cpxR. CONCLUSIONS A genomics approach has identified novel contributors to gain or loss of ciprofloxacin susceptibility in S. Typhi, expanding our understanding of the impact of fluoroquinolones on bacteria and of mechanisms that may contribute to resistance. The data also demonstrate the power of the TraDIS technology for antibacterial research.
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Affiliation(s)
- A Keith Turner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Sabine E Eckert
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Daniel J Turner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- Oxford Nanopore Technologies Ltd, Gosling Building, Edmund Halley Road, Oxford Science Park OX4 4DQ, UK
| | - Muhammud Yasir
- Quadram Institute, Norwich Research Park, Colney, Norwich NR4 7UA, UK
| | - Mark A Webber
- Quadram Institute, Norwich Research Park, Colney, Norwich NR4 7UA, UK
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Ian G Charles
- Quadram Institute, Norwich Research Park, Colney, Norwich NR4 7UA, UK
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Julian Parkhill
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK
| | - John Wain
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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Patil N, Mule P. Sensitivity Pattern Of Salmonella typhi And Paratyphi A Isolates To Chloramphenicol And Other Anti-Typhoid Drugs: An In Vitro Study. Infect Drug Resist 2019; 12:3217-3225. [PMID: 31686872 PMCID: PMC6800285 DOI: 10.2147/idr.s204618] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 06/07/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose To investigate the antimicrobial sensitivity pattern of commonly prescribed antimicrobials (chloramphenicol, cefixime, ofloxacin, azithromycin, and ceftriaxone) against Salmonella enterica isolates. Methods Blood culture positive isolates of S. typhi and S. paratyphi A (N = 251) received at Metropolis Healthcare Limited (Mumbai, India) from four zones of India (North, South, West, and East) between April and August 2018 were tested for antimicrobial susceptibility by E-test method. Based on the minimum inhibitory concentration (MIC), the organism was categorized as sensitive, intermediate, and resistant against the respective antibiotics as per Clinical and Laboratory Standards Institute criteria 2018. Results Out of 251 Salmonella isolates, 192 (76.5%) were S. typhi and 59 (23.5%) were S. paratyphi A. All 251 (100%) Salmonella isolates were sensitive to cefixime, ceftriaxone, and azithromycin; 237/251 (94.4%) isolates to chloramphenicol and only 9/251 (3.6%) isolates were sensitive to ofloxacin. Based on average MIC and MIC breakpoints, Salmonella isolates were found to be sensitive to chloramphenicol (MIC: 3.89±6.94 µg/mL), cefixime (MIC: 0.13±0.11 µg/mL), azithromycin (MIC: 3.32±2.19 µg/mL), and ceftriaxone (MIC: 0.11±0.18 µg/mL) and resistant to ofloxacin (MIC: 2.95±6.06 µg/mL). More than 20% of Salmonella isolates had MICs of chloramphenicol as 1.5 µg/mL (27.85% isolates) and 2 µg/mL (29.53% isolates). Conclusion Our study confirms the re‑emergence of susceptibility of Salmonella isolates to chloramphenicol. Further, the concern about fluoroquinolone-decreased susceptibility as indicated by the intermediate susceptibility or resistance was reiterated in this study. Though cefixime, azithromycin, and ceftriaxone showed susceptibility, the possibility of antibiotic resistance with the irrational use of these antibiotics cannot be deterred. This study thus emphasizes the need for continuous evaluation and judicious use of antimicrobials, considering the ever-changing landscape.
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Affiliation(s)
- Niranjan Patil
- Microbiology and Molecular Biology Department, Metropolis Healthcare Limited, Mumbai, India
| | - Prashant Mule
- Microbiology and Molecular Biology Department, Metropolis Healthcare Limited, Mumbai, India
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Liaquat S, Sarwar Y, Ali A, Haque A, Farooq M, Martinez-Ballesteros I, Laorden L, Garaizar J, Bikandi J. Virulotyping of Salmonella enterica serovar Typhi isolates from Pakistan: Absence of complete SPI-10 in Vi negative isolates. PLoS Negl Trop Dis 2018; 12:e0006839. [PMID: 30500817 PMCID: PMC6267989 DOI: 10.1371/journal.pntd.0006839] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 09/13/2018] [Indexed: 12/30/2022] Open
Abstract
The pathogenesis of Salmonella enterica serovar Typhi (S. Typhi), the cause of typhoid fever in humans, is mainly attributed to the acquisition of horizontally acquired DNA elements. Salmonella pathogenicity islands (SPIs) are indubitably the most important form of horizontally acquired DNA with respect to pathogenesis of this bacterium. The insertion or deletion of any of these transferrable SPIs may have impact on the virulence potential of S. Typhi. In this study, the virulence potential and genetic relatedness of 35 S. Typhi isolates, collected from 2004 to 2013 was determined by identification of SPI and non-SPI virulence factors through a combination of techniques including virulotyping, Whole Genome Sequencing (WGS), and Variable Number of Tandem Repeats (VNTR) profiling. In order to determine the virulence potential of local S. Typhi isolates, 56 virulence related genes were studied by PCR. These genes are located in the core as well as accessory genome (SPIs and plasmid). Major variations among studied virulence determinants were found in case of SPI-7 and SPI-10 associated genes. On the basis of presence of virulence related genes, the studied S. Typhi isolates from Pakistan were clustered into two virulotypes Vi-positive and Vi-negative. Interestingly, SPI-7 and SPI-10 were collectively absent or present in Vi-negative and Vi-positive strains, respectively. Two Vi-negative and 11 Vi-positive S. Typhi strains were also analyzed by whole genome sequencing (WGS) and their results supported the PCR results. Genetic diversity was tested by VNTR-based molecular typing. All 35 isolates were clustered into five groups. Overall, all Vi-negative isolates were placed in a single group (T5) whereas Vi-positive isolates were grouped into four types. Vi-negative and Vi-positive isolates were mutually exclusive. This is the first report on the comparative distribution of SPI and non-SPI related virulence genes in Vi-negative and Vi-positive S. Typhi isolates with an important finding that SPI-10 is absent in all Vi-negative isolates. The distribution of virulence factors in S. Typhi can vary in isolates from different geographical regions and can have significant effect on the disease control. In this study, we have checked the distribution of 56 reported virulence associated factors in 35 local isolates of S. Typhi to identify any variations that can help in designing effective control strategies for typhoid. We have identified four naturally occurring variants which are simultaneously lacking SPI-7 and SPI-10, two adjacently located pathogenicity islands on S. Typhi chromosome. These isolates are not producing Vi capsular antigen hence the Vi based vaccines will not be effective against them. These findings highlight the need to develop typhoid vaccines specifically effective in Pakistan.
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Affiliation(s)
- Sadia Liaquat
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
- Departments of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Yasra Sarwar
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
- * E-mail:
| | - Aamir Ali
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Abdul Haque
- Akhuwat Faisalabad Institute For Research In Science And Technology, Faisalabad, Pakistan
| | - Muhammad Farooq
- Enteric Pathogen Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan affiliated with Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Ilargi Martinez-Ballesteros
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Lorena Laorden
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Javier Garaizar
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Joseba Bikandi
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country, (UPV/EHU), Vitoria-Gasteiz, Spain
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Abatcha MG, Effarizah ME, Rusul G. Prevalence, antimicrobial resistance, resistance genes and class 1 integrons of Salmonella serovars in leafy vegetables, chicken carcasses and related processing environments in Malaysian fresh food markets. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.02.039] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Barac R, Als D, Radhakrishnan A, Gaffey MF, Bhutta ZA, Barwick M. Implementation of Interventions for the Control of Typhoid Fever in Low- and Middle-Income Countries. Am J Trop Med Hyg 2018; 99:79-88. [PMID: 30047365 PMCID: PMC6128369 DOI: 10.4269/ajtmh.18-0110] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/05/2018] [Indexed: 01/12/2023] Open
Abstract
Past research has focused on typhoid fever surveillance with little attention to implementation methods or effectiveness of control interventions. This study purposefully sampled key informants working in public health in Chile, India, Pakistan, Bangladesh, Thailand, Vietnam, South Africa, and Nigeria to 1) scope typhoid-relevant interventions implemented between 1990 and 2015 and 2) explore contextual factors perceived to be associated with their implementation, based on the Consolidated Framework for Implementation Research (CFIR). We used a mixed methods design and collected quantitative data (CFIR questionnaire) and qualitative data (interviews with 34 public health experts). Interview data were analyzed using a deductive qualitative content analysis and summary descriptive statistics are provided for the CFIR data. Despite relatively few typhoid-specific interventions reportedly implemented in these countries, interventions for diarrheal disease control and regulations for food safety and food handlers were common. Most countries implemented agricultural and sewage treatment practices, yet few addressed the control of antibiotic medication. Several contextual factors were perceived to have influenced the implementation of typhoid interventions, either as enablers (e.g., economic development) or barriers (e.g., limited resources and habitual behaviors). Consolidated Framework for Implementation Research factors rated as important in the implementation of typhoid interventions were remarkably consistent across countries. The findings provide a snapshot of typhoid-relevant interventions implemented over 25 years and highlight factors associated with implementation success from the perspective of a sample of key informants. These findings can inform systematic investigations of the implementation of typhoid control interventions and contribute to a better understanding of the direct effects of implementation efforts.
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Affiliation(s)
- Raluca Barac
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Daina Als
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | | | - Michelle F. Gaffey
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | - Zulfiqar A. Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Melanie Barwick
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
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12
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Djeghout B, Saha S, Sajib MSI, Tanmoy AM, Islam M, Kay GL, Langridge GC, Endtz HP, Wain J, Saha SK. Ceftriaxone-resistant Salmonella Typhi carries an IncI1-ST31 plasmid encoding CTX-M-15. J Med Microbiol 2018; 67:620-627. [PMID: 29616895 DOI: 10.1099/jmm.0.000727] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Ceftriaxone is the drug of choice for typhoid fever and the emergence of resistant Salmonella Typhi raises major concerns for treatment. There are an increasing number of sporadic reports of ceftriaxone-resistant S. Typhi and limiting the risk of treatment failure in the patient and outbreaks in the community must be prioritized. This study describes the use of whole genome sequencing to guide outbreak identification and case management. METHODOLOGY An isolate of ceftriaxone-resistant S. Typhi from the blood of a child taken in 2000 at the Popular Diagnostic Center, Dhaka, Bangladesh was subjected to whole genome sequencing, using an Illumina NextSeq 500 and analysis using Geneious software.Results/Key findings. Comparison with other ceftriaxone-resistant S. Typhi revealed an isolate from the Democratic Republic of the Congo in 2015 as the closest relative but no evidence of an outbreak. A plasmid belonging to incompatibility group I1 (IncI1-ST31) which included blaCTX-M-15 (ceftriaxone resistance) associated with ISEcp-1 was identified. High similarity (90 %) was seen with pS115, an IncI1 plasmid from S. Enteritidis, and with pESBL-EA11, an incI1 plasmid from E. coli (99 %) showing that S. Typhi has access to ceftriaxone resistance through the acquisition of common plasmids. CONCLUSIONS The transmission of ceftriaxone resistance from E. coli to S. Typhi is of concern because of clinical resistance to ceftriaxone, the main stay of typhoid treatment. Whole genome sequencing, albeit several years after the isolation, demonstrated the success of containment but clinical trials with alternative agents are urgently required.
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Affiliation(s)
- Bilal Djeghout
- Laboratory of Microbiology and Virology, Department of Biomedical Sciences, University of Sassari, V. le San Pietro 43/B, 07100 Sassari, Italy
| | - Senjuti Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh.,Bangladesh Institute of Child Health, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Mohammad Saiful Islam Sajib
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh.,Bangladesh Institute of Child Health, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Arif Mohammad Tanmoy
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh.,Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Maksuda Islam
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh.,Bangladesh Institute of Child Health, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Gemma L Kay
- Medical Microbiology Research Laboratory, Norwich Medical School, University of East Anglia, Norwich, NR4 7UQ, UK
| | - Gemma C Langridge
- Medical Microbiology Research Laboratory, Norwich Medical School, University of East Anglia, Norwich, NR4 7UQ, UK
| | - Hubert P Endtz
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Centre, Rotterdam, the Netherlands.,Laboratoire des Pathogènes Émergents, Fondation Mérieux, Centre International de Recherche en Infectiologie (CIRI), INSERM U1111, Lyon, France
| | - John Wain
- Medical Microbiology Research Laboratory, Norwich Medical School, University of East Anglia, Norwich, NR4 7UQ, UK
| | - Samir K Saha
- Bangladesh Institute of Child Health, Dhaka Shishu Hospital, Dhaka, Bangladesh.,Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
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13
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Akinyemi KO, Ajoseh SO, Iwalokun BA, Oyefolu AOB, Fakorede CO, Abegunrin RO, Adunmo O. Antimicrobial Resistance and Plasmid Profiles of <i>Salmonella enterica</i> Serovars from Different Sources in Lagos, Nigeria. Health (London) 2018. [DOI: 10.4236/health.2018.106058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Kuijpers LMF, Phe T, Veng CH, Lim K, Ieng S, Kham C, Fawal N, Fabre L, Le Hello S, Vlieghe E, Weill FX, Jacobs J, Peetermans WE. The clinical and microbiological characteristics of enteric fever in Cambodia, 2008-2015. PLoS Negl Trop Dis 2017; 11:e0005964. [PMID: 28931025 PMCID: PMC5624643 DOI: 10.1371/journal.pntd.0005964] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 10/02/2017] [Accepted: 09/14/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Enteric fever remains a major public health problem in low resource settings and antibiotic resistance is increasing. In Asia, an increasing proportion of infections is caused by Salmonella enterica serovar Paratyphi A, which for a long time was assumed to cause a milder clinical syndrome compared to Salmonella enterica serovar Typhi. METHODOLOGY A retrospective chart review study was conducted of 254 unique cases of blood culture confirmed enteric fever who presented at a referral adult hospital in Phnom Penh, Cambodia between 2008 and 2015. Demographic, clinical and laboratory data were collected from clinical charts and antibiotic susceptibility testing was performed. Whole genome sequence analysis was performed on a subset of 121 isolates. RESULTS One-hundred-and-ninety unique patients were diagnosed with Salmonella Paratyphi A and 64 with Salmonella Typhi. In the period 2008-2012, Salmonella Paratyphi A comprised 25.5% of 47 enteric fever cases compared to 86.0% of 207 cases during 2013-2015. Presenting symptoms were identical for both serovars but higher median leukocyte counts (6.8 x 109/L vs. 6.3 x 109/L; p = 0.035) and C-reactive protein (CRP) values (47.0 mg/L vs. 36 mg/L; p = 0.034) were observed for Salmonella Typhi infections. All but one of the Salmonella Typhi isolates belonged to haplotype H58 associated with multidrug resistance (MDR) (i.e. resistance to ampicillin, chloramphenicol and co-trimoxazole).;42.9% actually displayed MDR compared to none of the Salmonella Paratyphi A isolates. Decreased ciprofloxacin susceptibility (DCS) was observed in 96.9% (62/64) of Salmonella Typhi isolates versus 11.5% (21/183) of Salmonella Paratyphi A isolates (all but one from 2015). All isolates were susceptible to azithromycin and ceftriaxone. CONCLUSIONS In Phnom Penh, Cambodia, Salmonella Paratyphi A now causes the majority of enteric fever cases and decreased susceptibility against ciprofloxacin is increasing. Overall, Salmonella Typhi was significantly more associated with MDR and DCS compared to Salmonella Paratyphi A.
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Affiliation(s)
- Laura M. F. Kuijpers
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology & Immunology, KU Leuven, Leuven, Belgium
- * E-mail:
| | - Thong Phe
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Chhun H. Veng
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Kruy Lim
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Sovann Ieng
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Chun Kham
- Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia
| | - Nizar Fawal
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Laetitia Fabre
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Simon Le Hello
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Erika Vlieghe
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of General Internal Medicine, Infectious diseases and Tropical Medicine, University Hospital Antwerp, Antwerp, Belgium
| | - François-Xavier Weill
- Unité des Bactéries Pathogènes Entériques, Centre National de Référence des E. coli, Shigella et Salmonella, Institut Pasteur, Paris, France
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology & Immunology, KU Leuven, Leuven, Belgium
| | - Willy E. Peetermans
- Department of Internal Medicine, University Hospital Leuven, Leuven, Belgium
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15
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Das S, Samajpati S, Roy I, Sankar S, Gaind R, Deb M, Kulkarni R, Paul DK, Dutta S. Molecular Subtyping of Salmonella enterica Serovar Typhi by Pulsed-Field Gel Electrophoresis and Multiple-Locus Variable-Number Tandem-Repeat Analysis in India: Their Association with Antimicrobial Resistance Profiles. Jpn J Infect Dis 2017; 70:536-543. [PMID: 28674312 DOI: 10.7883/yoken.jjid.2016.478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Molecular subtyping and DNA sequencing-based methods, which are commonly used for discriminating Salmonella enterica serovar Typhi (S. Typhi) isolates, lead to improved molecular epidemiological investigations for prevention and control of typhoid fever. We obtained S. Typhi blood isolates (n = 66) from India during 2007-14 for molecular subtyping by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) in association with antibiotic resistance profiles. Genotypic diversity was observed more by MLVA (Simpson's index of diversity, D value = 0.997) than PFGE (D value = 0.864). Two prevalent pulsotypes containing nalidixic acid-resistant (NALR) and NALR-ciprofloxacin-resistant (CIPR) S. Typhi isolates circulated in India. Multidrug-resistant (MDR), NALR-CIPR, and most NALR isolates were found to be clonal by PFGE. MLVA could differentiate the clonal isolates. Most of the MDR and NALR-CIPR isolates showed variation in single or double VNTR loci, whereas NALR isolates varied in more than 2 loci, reflecting higher genetic diversity among the NALR isolates. Of the 6 VNTR loci, TR4,699 (D value = 0.838) and Sal02 (D value = 0.890) loci played important roles as MLVA cluster-supporting alleles. The rapid turnaround time and high-level discriminatory power of MLVA may be useful for tracking and controlling the transmission of S. Typhi isolates during epidemiological investigations.
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Affiliation(s)
- Surojit Das
- Microbiology Division, National Institute of Cholera and Enteric Diseases
| | - Sriparna Samajpati
- Microbiology Division, National Institute of Cholera and Enteric Diseases
| | - Indranil Roy
- Microbiology Division, Calcutta Medical Research Institute
| | - Sathish Sankar
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital & Research Centre
| | - Rajni Gaind
- Microbiology Division, Vardhaman Mahavir Medical College & Safdarjung Hospital
| | - Monorama Deb
- Microbiology Division, Vardhaman Mahavir Medical College & Safdarjung Hospital
| | | | - Dilip Kumar Paul
- Clinical Division, Dr. B. C. Roy Post Graduate Institute of Pediatric Sciences
| | - Shanta Dutta
- Microbiology Division, National Institute of Cholera and Enteric Diseases
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Chinnasami B, Sadasivam K, Vivekanandhan A, Arunachalam P, Pasupathy S. A Study on Longevity of Immune Response after Vaccination with Salmonella Typhi Vi Conjugate Vaccine (Pedatyph™) in Children. J Clin Diagn Res 2015; 9:SC01-3. [PMID: 26155525 DOI: 10.7860/jcdr/2015/13302.5903] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/05/2015] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Owing to the limitations of the conventional polysaccharide vaccines, global efforts have been made to develop conjugated polysaccharide vaccines for typhoid. Duration of immune response induced by these vaccines is critical to define the efficacy and frequency of required booster dose. This study was done to determine the duration of immune response following vaccination with Salmonella Typhi Vi conjugate vaccine (Pedatyph™) in children and to assess the booster effect of second dose of conjugate typhoid vaccine. MATERIALS AND METHODS Forty children were recalled from a cohort of 400 children, who received one dose or two doses of PedaTyph™, 30 months after vaccination. Ten non-vaccinated children were also recalled. Their serum samples were assessed by ELISA for anti Vi antibody. RESULTS Significantly high titers of anti-Vi polysaccharide IgG antibodies were present in vaccinated children even after 30 months of vaccination as compared to non-vaccinated children. Geometric mean titers (GMT) with 95% confidence intervals were 14 (4.8-29.8), 17 (7.4-33) and 6.4 (0.8-12) μg/ml for single dose, two doses and control group respectively. The children in two doses group had higher antibody titers as compared to single dose group. However, the difference was not significant. INTERPRETATION AND CONCLUSION PedaTyph™ was found to induce long term immune response as evidenced by presence of significant anti-Vi polysaccharide antibodies after 30 months of vaccination. No significant advantage of two doses regimen over one dose was found. Hence one dose vaccination with PedaTyph™ is suggested.
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Affiliation(s)
- Balaji Chinnasami
- Associate Professor, Department of Paediatrics, SRM MCH& RC , Chennai, India
| | | | - Aravindhan Vivekanandhan
- Researcher, Department of Immunology and Molecular Biology, AU-KBC Research Centre, MIT Campus of Anna University , Chrompet, Chennai, India
| | - Prema Arunachalam
- Former, Professor & HOD, Department of Paediatrics, SRM MCH& RC , Chennai, India
| | - Sekar Pasupathy
- Professor & HOD, Department of Paediatrics, SRM MCH& RC , Chennai, India
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17
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Abstract
Control of typhoid fever relies on clinical information, diagnosis, and an understanding for the epidemiology of the disease. Despite the breadth of work done so far, much is not known about the biology of this human-adapted bacterial pathogen and the complexity of the disease in endemic areas, especially those in Africa. The main barriers to control are vaccines that are not immunogenic in very young children and the development of multidrug resistance, which threatens efficacy of antimicrobial chemotherapy. Clinicians, microbiologists, and epidemiologists worldwide need to be familiar with shifting trends in enteric fever. This knowledge is crucial, both to control the disease and to manage cases. Additionally, salmonella serovars that cause human infection can change over time and location. In areas of Asia, multidrug-resistant Salmonella enterica serovar Typhi (S Typhi) has been the main cause of enteric fever, but now S Typhi is being displaced by infections with drug-resistant S enterica serovar Paratyphi A. New conjugate vaccines are imminent and new treatments have been promised, but the engagement of local medical and public health institutions in endemic areas is needed to allow surveillance and to implement control measures.
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Affiliation(s)
- John Wain
- Norwich Medical School, University of East Anglia, Norwich, UK.
| | - Rene S Hendriksen
- National Food Institute, Technical University of Denmark, WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and European Union Reference Laboratory for Antimicrobial Resistance, Kongens Lyngby, Denmark
| | - Matthew L Mikoleit
- National Enteric Reference Laboratory Team, Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Karen H Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases, Division in the National Health Laboratory Service (NHLS), Johannesburg, South Africa; Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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18
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Gupta R, Gaind R, Wain J, Deb M, Singh LC, Basir SF. Characterization of non-classical quinolone resistance in Salmonella enterica serovar Typhi: Report of a novel mutation in gyrB gene and diagnostic challenges. BIOMOLECULAR DETECTION AND QUANTIFICATION 2015; 2:30-34. [PMID: 27896141 PMCID: PMC5121207 DOI: 10.1016/j.bdq.2015.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 01/13/2015] [Accepted: 01/13/2015] [Indexed: 11/18/2022]
Abstract
Objective To establish the relative importance of Salmonella enterica serovar Typhi with non-classical quinolone resistance. Methods Eight hundred and ninety-one isolates of S. Typhi, isolated between 2004 and 2011, were tested for antibiotic susceptibility determination using disc diffusion and E-test. The mechanisms of fluoroquinolone resistance were studied in a sub-set of the NALS (nalidixic acid susceptible) isolates by wave nucleic acid fragment analysis of PCR products from gyrA, gyrB, parC and parE and from the plasmid borne determinants: qnrA,B,S; aac(6′)-Ib-cr and qepA. To assess genetic relatedness multi-locus variable number tandem repeat analysis was carried out using five loci. Results Eighty isolates with a nalidixic acid MIC of <32 mg/L (NALS) and a ciprofloxacin MIC of >0.064 mg/L CIPI (ciprofloxacin reduced susceptibility) were found. In 36 NALS CIPI isolates two distinct genotypes were identified when compared with 16 susceptible controls: Group B (n = 34), mutation in gyrB at codon 464, NAL MIC of 3–12 mg/L and CIP MIC of 0.064–0.5 mg/L.; and Group C, mutation in gyrA at codon 83 (n = 2) NAL MIC of 16 mg/L and CIP MIC of 0.25–0.38 mg/L. Group B isolates were found in different strain backgrounds as defined by MLVA. Conclusion The use of nalidixic acid to screen for reduced susceptibility to fluoroquinolones in S. Typhi misses CIPI-NALS isolates, an established phenotype in India.
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Affiliation(s)
- Ruchi Gupta
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi 110029, India
| | - Rajni Gaind
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi 110029, India
- Corresponding author. Tel.: +91 9810528344; fax: +91 11 27123677.
| | - John Wain
- Norwich Medical School, University of East Anglia, NRP Innovation Centre, Norwich Research Park, Colney Lane, Norwich, Norfolk NR4 7GJ, United Kingdom
| | - Monorama Deb
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi 110029, India
| | | | - Seemi Farhat Basir
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
- Corresponding author. Tel.: +91 9810597159.
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Shaheen A, Ismat F, Iqbal M, Haque A, De Zorzi R, Mirza O, Walz T, Rahman M. Characterization of putative multidrug resistance transporters of the major facilitator-superfamily expressed in Salmonella Typhi. J Infect Chemother 2015; 21:357-62. [PMID: 25724589 DOI: 10.1016/j.jiac.2015.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/03/2014] [Accepted: 01/02/2015] [Indexed: 01/11/2023]
Abstract
Multidrug resistance mediated by efflux pumps is a well-known phenomenon in infectious bacteria. Although much work has been carried out to characterize multidrug efflux pumps in Gram-negative and Gram-positive bacteria, such information is still lacking for many deadly pathogens. The aim of this study was to gain insight into the substrate specificity of previously uncharacterized transporters of Salmonella Typhi to identify their role in the development of multidrug resistance. S. Typhi genes encoding putative members of the major facilitator superfamily were cloned and expressed in the drug-hypersensitive Escherichia coli strain KAM42, and tested for transport of 25 antibacterial compounds, including representative antibiotics of various classes, antiseptics, dyes and detergents. Of the 15 tested putative transporters, STY0901, STY2458 and STY4874 exhibited a drug-resistance phenotype. Among these, STY4874 conferred resistance to at least ten of the tested antimicrobials: ciprofloxacin, norfloxacin, levofloxacin, kanamycin, streptomycin, gentamycin, nalidixic acid, chloramphenicol, ethidium bromide, and acriflavine, including fluoroquinolone antibiotics, which were drugs of choice to treat S. Typhi infections. Cell-based functional studies using ethidium bromide and acriflavine showed that STY4874 functions as a H(+)-dependent exporter. These results suggest that STY4874 may be an important drug target, which can now be tested by studying the susceptibility of a STY4874-deficient S. Typhi strain to antimicrobials.
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Affiliation(s)
- Aqsa Shaheen
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Fouzia Ismat
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Mazhar Iqbal
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan
| | - Abdul Haque
- The University of Faisalabad, Faisalabad, Pakistan
| | - Rita De Zorzi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Osman Mirza
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Walz
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Moazur Rahman
- Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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20
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Abstract
Infections with Salmonella are an important public health problem worldwide. Salmonella are one of the most common causes of food-borne illness in humans. There are many types of Salmonella but they can be divided into two broad categories: those that cause typhoid and those that do not. The typhoidal Salmonella (TS), such as S. enterica subsp. enterica serovars Typhi and S. Paratyphi only colonize humans and are usually acquired by the consumption of food or water contaminated with human fecal material. The much broader group of non-typhoidal Salmonella (NTS) usually results from improperly handled food that has been contaminated by animal or human fecal material. Antimicrobials are critical to the successful outcome of invasive Salmonella infections and enteric fever. Due to resistance to the older antimicrobials, ciprofloxacin [fluoroquinolone (FQ)] has become the first-line drug for treatment. Nevertheless, switch to FQ has led to a subsequent increase in the occurrence of salmonellae resistant to this antimicrobial agent. The exact mechanism of this FQ resistance is not fully understood. FQ resistance has driven the use of third-generation cephalosporins and azithromycin. However, there are sporadic worldwide reports of high level resistance to expanded-spectrum cephalosporins (such as ceftriaxone) in TS and in NTS it has been recognized since 1988 and are increasing in prevalence worldwide. Already there are rare reports of azithromycin resistance leading to treatment failure. Spread of such resistance would further greatly limit the available therapeutic options, and leave us with only the reserve antimicrobials such as carbapenem and tigecycline as possible treatment options. Here, we describe the methods involved in the genotypic characterization of antimicrobial resistance in clinical isolates of salmonellae.
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Affiliation(s)
- Belgode N Harish
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India,
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21
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Gibert M, Juárez A, Zechner EL, Madrid C, Balsalobre C. TrhR, TrhY and HtdA, a novel regulatory circuit that modulates conjugation of the IncHI plasmids. Mol Microbiol 2014; 94:1146-1161. [PMID: 25302406 DOI: 10.1111/mmi.12823] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2014] [Indexed: 11/28/2022]
Abstract
Bacterial conjugation promotes horizontal gene transfer and, consequently, the acquisition of new capabilities such as resistance to antimicrobial compounds and virulence related traits. Conjugative plasmids belonging to the incompatibility group HI are associated with multidrug resistance in Gram-negative pathogens. IncHI plasmid conjugation is thermodependent and all transfer-related genes are encoded in six operons (tra operons). Using R27, the prototype of IncHI1 plasmids, we reported that the plasmid-encoded factor HtdA represses four of the six tra operons. Moreover, our results indicated that other R27 factors were required for appropriate expression of the tra genes. In this report, using R27 libraries and random mutagenesis assays, two genes - trhR and trhY - have been identified as essential for the transcriptional expression of four tra operons and, accordingly, for the R27 conjugation. TrhR and TrhY are required simultaneously and their stimulatory activity is counteracted by HtdA. Functional and physical interactions between TrhR, TrhY and HtdA suggest that they form a three-element regulatory circuit that controls conjugation of IncHI plasmids. Expression studies suggest that H-NS represses conjugation at high temperature by repressing trhR expression. Remarkably, we show that this regulatory circuit is highly conserved among the IncHI plasmids.
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Affiliation(s)
- M Gibert
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
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DeRoeck D, Ochiai RL, Yang J, Anh DD, Alag V, Clemens JD. Typhoid vaccination: the Asian experience. Expert Rev Vaccines 2014; 7:547-60. [DOI: 10.1586/14760584.7.5.547] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Girish R, Kumar A, Khan S, Dinesh KR, Karim S. Revised Ciprofloxacin Breakpoints for Salmonella: Is it Time to Write an Obituary? J Clin Diagn Res 2013; 7:2467-9. [PMID: 24392374 DOI: 10.7860/jcdr/2013/7312.3581] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/18/2013] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To determine the minimum inhibitory concentration of ciprofloxacin among 50 blood stream isolates of Salmonella enterica. MATERIAL AND METHODS A total of 50 consecutive isolates of Salmonella enterica were tested for susceptibility to antimicrobials using the Kirby Bauer disk diffusion method. Minimum inhibitory concentrations were determined using Hi-Comb strips. All results were interpreted according to the CLSI guidelines. RESULTS Of the 50 isolates 70%were Salmonella Typhi, 4% Salmonella paratyphi A, 2% Salmonella paratyphi B and the remaining 10% were identified only as Salmonella species. Using the CLSI 2011 breakpoints for disc diffusion, 86% (43/50) were resistant to nalidixic acid(NA), 22% (11/50) to ciprofloxacin, 12% to azithromycin, 6% to cotrimoxazole, 4% to ampicillin and 1% to chloramphenicol. The MIC50 and MIC90 of ciprofloxacin for S.Typhi were 0.181 μg/mL and 5.06 μg/mL respectively. While the same for S. paratyphi A was 0.212μg/mL and 0.228μg/mL respectively. None of the isolates were multi drug resistant and all were susceptible to ceftriaxone. Using the CLSI 2012 revised ciprofloxacin breakpoints for disc diffusion (>31mm) & MIC (<0.06 μg/mL), 90% (45/50) of these isolates were found to be resistant. CONCLUSION MIC's of ciprofloxacin should be reported for all salmonella isolates and should be used to guide treatment. Blindly following western guidelines for a disease which is highly endemic in the subcontinent will spell the death knell of a cheap and effective drug in our armamentarium. Therefore it will be too premature to declare that "the concept of using ciprofloxacin in typhoid fever is dead!"
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Affiliation(s)
- Revathy Girish
- MSc, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India
| | - Anil Kumar
- Clinical Associate Professor, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India
| | - Sadia Khan
- Clinical Assistant Professor, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala, India
| | - Kavitha R Dinesh
- Clinical Professor, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India
| | - Shamsul Karim
- Professor & Head, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India
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Al-Tawfiq JA. Antimicrobial Susceptibility ofSalmonella typhiand Non-typhiin a Hospital in Eastern Saudi Arabia. J Chemother 2013; 19:62-5. [PMID: 17309853 DOI: 10.1179/joc.2007.19.1.62] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The objective of this study was to determine the antimicrobial susceptibility of Salmonella typhi and non-typhi at Saudi Aramco Medical Services Organization (SAMSO). We retrospectively identified isolates of S. typhi and non-typhi from January 1996 to December 2003. Antimicrobial sensitivity and clinical data were collected and analyzed. A total of 266 distinct isolates of S. typhi and non- typhi were available for analysis. Of the total isolates, 21.4% (n= 57) were S. typhi and 78.6% (n= 209) were Salmonella non-typhi and their most common serogroups were D (20.3%), C (19.5%) and B (15.8%). None of Salmonella spp. was resistant to ceftriaxone or ciprofloxacin. The susceptibility of S. typhi and non- typhi to trimethoprim-sulfamethoxazole (TMP-SMX) was 89% and 84% (P = 0.3) and to tetracycline was 81.3% and 56.6%, respectively (P <0.001). Ampicillin susceptibility was detected in 89% and 77% of S. typhi and non-typhi, respectively (P = 0.038). Multidrug resistance was present in 20% of S. typhi and 18.9% of Salmonella nontyphi. There was no difference in the susceptibility pattern of salmonella between Saudi and non-Saudi patients except for gentamicin susceptibility (97.3% vs. 65.9%, P < 0.001).
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Affiliation(s)
- J A Al-Tawfiq
- Internal Medicine Services Division, Dhahran Health Center, Saudi Aramco Medical Services Organization, Saudi Aramco, Dhahran, Saudi Arabia.
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Cooke FJ, Wain J. The emergence of antibiotic resistance in typhoid fever. Travel Med Infect Dis 2012; 2:67-74. [PMID: 17291961 DOI: 10.1016/j.tmaid.2004.04.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Accepted: 04/19/2004] [Indexed: 10/26/2022]
Abstract
Typhoid fever, caused by Salmonella typhi, causes over 20 million cases annually, with at least 700,000 deaths. The main burden of disease is in developing countries, particularly the Indian Subcontinent and South East Asia. However, cases in returning travellers, immigrants and refugees in developed countries are not uncommon. Drug resistance is fast becoming a major problem in the management of this infection. Chloramphenicol resistance became established globally in the S.Typhi population after 1972 on plasmids of incompatibility group IncH. Multi-drug resistance defined as resistance to the three first-line agents used to treat typhoid fever, namely chloramphenicol, ampicillin and co-trimoxazole, and acquired on the same plasmid type, has been endemic in most of South East Asia and the Indian Subcontinent for many years. Resistance data from many endemic areas are sparse and with the increasing problem of reduced sensitivity to the fluoroquinolone antibiotics, empirical choice of antibiotics may be difficult. We review the historical aspects of the development of resistance and the current data available on the epidemiology of antibiotic resistance in S.Typhi.
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Affiliation(s)
- Fiona J Cooke
- Centre for Molecular Microbiology and Infection, Level 1, Flowers Building, Imperial College, London SW7 2AZ, UK
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Instability of Escherichia coli R-factors in Salmonella enterica serovar Typhi involves formation of recombinant composite plasmid structures. Plasmid 2012; 68:125-32. [PMID: 22579995 DOI: 10.1016/j.plasmid.2012.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 04/10/2012] [Accepted: 04/30/2012] [Indexed: 11/23/2022]
Abstract
In spite of a well-documented ability of Samonella enterica Typhi strains to receive R factors from Escherichia coli and other enterobacteria, epidemiological data show that Typhi is a rather poor host of antibiotic-resistance genes and in fact, of plasmids, suggesting that most of the plasmids naturally acquired by Typhi strains become unstable and eventually segregate. We have previously reported evidence that each of three plasmids conjugatively transferred to S. enterica Typhi experienced deletion-mediated loss of a resistance determinant before plasmid segregation occurred. We now report that in Typhi strains containing these unstable plasmids a superhelical DNA species of lower mobility is detected, probably representing plasmid dimer structures. Plasmid deletion is a RecA-dependent process since it is not detected in derivatives of a recA1 S. enterica Typhi strain containing the corresponding plasmids, and in such strains we were unable to detect either the low-mobility species. We propose that the deletable segments contain key information for plasmid stability in S. enterica Typhi, possibly a multimer resolution system.
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Abstract
Infections with Salmonella are an important public health problem worldwide. On a global scale, it has been appraised that Salmonella is responsible for an estimated 3 billion human infections each year. The World Health Organization (WHO) has estimated that annually typhoid fever accounts for 21.7 million illnesses (217,000 deaths) and paratyphoid fever accounts for 5.4 million of these cases. Infants, children, and adolescents in south-central and South-eastern Asia experience the greatest burden of illness. In cases of enteric fever, including infections with S. Typhi and S. Paratyphi A and B, it is often necessary to commence treatment before the results of laboratory sensitivity tests are available. Hence, it is important to be aware of options and possible problems before beginning treatment. Ciprofloxacin has become the first-line drug of choice since the widespread emergence and spread of strains resistant to chloramphenicol, ampicillin, and trimethoprim. There is increase in the occurrence of strains resistant to ciprofloxacin. Reports of typhoidal salmonellae with increasing minimum inhibitory concentration (MIC) and resistance to newer quinolones raise the fear of potential treatment failures and necessitate the need for new, alternative antimicrobials. Extended-spectrum cephalosporins and azithromycin are the options available for the treatment of enteric fever. The emergence of broad spectrum β-lactamases in typhoidal salmonellae constitutes a new challenge. Already there are rare reports of azithromycin resistance in typhoidal salmonellae leading to treatment failure. This review is based on published research from our centre and literature from elsewhere in the world. This brief review tries to summarize the history and recent trends in antimicrobial resistance in typhoidal salmonellae.
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Affiliation(s)
- B N Harish
- Department of Microbiology, Institute of National Importance, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry - 605 006, India.
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Accou-Demartin M, Gaborieau V, Song Y, Roumagnac P, Marchou B, Achtman M, Weill FX. Salmonella entericaSerotype Typhi with Nonclassical Quinolone Resistance Phenotype. Emerg Infect Dis 2011; 17:1091-4. [DOI: 10.3201/eid/1706.101242] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Accou-Demartin M, Gaborieau V, Song Y, Roumagnac P, Marchou B, Achtman M, Weill FX. Salmonella entericaSerotype Typhi with Nonclassical Quinolone Resistance Phenotype. Emerg Infect Dis 2011. [PMID: 21749778 PMCID: PMC3358197 DOI: 10.3201/eid1706.101242] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report Salmonella enterica serotype Typhi strains with a nonclassical quinolone resistance phenotype (i.e., decreased susceptibility to ciprofloxacin but with susceptibility to nalidixic acid) associated with a nonsynonymous mutation at codon 464 of the gyrB gene. These strains, not detected by the nalidixic acid disk screening test, can result in fluoroquinolone treatment failure.
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Dong BQ, Yang J, Wang XY, Gong J, von Seidlein L, Wang ML, Lin M, Liao HZ, Ochiai RL, Xu ZY, Jodar L, Clemens JD. Trends and disease burden of enteric fever in Guangxi province, China, 1994-2004. Bull World Health Organ 2010; 88:689-96. [PMID: 20865074 PMCID: PMC2930361 DOI: 10.2471/blt.09.069310] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 02/13/2010] [Accepted: 02/15/2010] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To determine the burden of enteric fever through trends in morbidity and mortality, bacterial species and antimicrobial resistance in Guangxi, a southern, subtropical, coastal province of China with a disproportionally large burden of enteric fever. METHODS Data on morbidity and mortality caused by enteric fever between 1994 and 2004 were extracted from the Guangxi Center for Disease Control and Prevention. Laboratory-based surveillance and outbreak investigations were integrated with reports of notifiable infectious diseases to estimate the bacterial species-specific incidence of enteric fever. To adjust for underreporting, survey data were collected from three prefectures that represent the hyper-, moderate- and low-endemic regions of Guangxi province. FINDINGS In Guangxi province, enteric fever incidence rate varied over the study period, with a peak of 13.5 cases per 100 000 population in 1995 and a low of 6.5 in 2003. The disease occurred most frequently during the summer and autumn months and in the group aged 10-49 years. The incidence of enteric fever varied by region within Guangxi province. During the 11-year period covered by the study, 61 outbreaks of enteric fever were reported, and Salmonella paratyphi A (SPA) became the predominant causative agent in the province. CONCLUSION Prospective studies may provide a better understanding of the reason for the shifting epidemiology of enteric fever in Guangxi province. Given the emergence of resistance to first- and second-line antimicrobials for the treatment of enteric fever, a bivalent vaccine against both SPA and S. typhi would facilitate for disease control.
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Affiliation(s)
- Bai-Qing Dong
- Guangxi Center for Disease Control and Prevention, Nanning, Guangxi, China
| | - Jin Yang
- Guangxi Center for Disease Control and Prevention, Nanning, Guangxi, China
| | - Xuan-Yi Wang
- Institutes of Biomedical Sciences, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China
| | - Jian Gong
- Guangxi Center for Disease Control and Prevention, Nanning, Guangxi, China
| | | | - Ming-Liu Wang
- Guangxi Center for Disease Control and Prevention, Nanning, Guangxi, China
| | - Mei Lin
- Guangxi Center for Disease Control and Prevention, Nanning, Guangxi, China
| | - He-Zhuang Liao
- Guangxi Center for Disease Control and Prevention, Nanning, Guangxi, China
| | - R Leon Ochiai
- International Vaccine Institute, Seoul, Republic of Korea
| | - Zhi-Yi Xu
- International Vaccine Institute, Seoul, Republic of Korea
| | - Luis Jodar
- International Vaccine Institute, Seoul, Republic of Korea
| | - John D Clemens
- International Vaccine Institute, Seoul, Republic of Korea
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Inhibition of intracellular growth of Salmonella enterica serovar Typhimurium in tissue culture by antisense peptide-phosphorodiamidate morpholino oligomer. Antimicrob Agents Chemother 2009; 53:3700-4. [PMID: 19581453 DOI: 10.1128/aac.00099-09] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Two types of phosphorodiamidate morpholino oligomers (PMOs) were tested for inhibition of growth of Salmonella enterica serovar Typhimurium. Both PMOs have the same 11-base sequence that is antisense to the region near the start codon of acpP, which is essential for lipid biosynthesis and viability. To the 3' end of each is attached the membrane-penetrating peptide (RXR)4XB (R, X, and B indicate arginine, 6-aminohexanoic acid, and beta-alanine, respectively). One peptide-PMO (AcpP PPMO) has no charge on the PMO moiety. The second PPMO has three cations (piperazine) attached to the phosphorodiamidate linkages (3+Pip-AcpP PPMO). A scrambled-sequence PPMO (Scr PPMO) was synthesized for each type of PMO. The MICs of AcpP PPMO, 3+Pip-AcpP PPMO, and either one of the Scr PPMOs were 1.25 microM (7 microg/ml), 0.156 microM (0.94 microg/ml), and >160 microM (>900 microg/ml), respectively. 3+Pip-AcpP PPMO at 1.25 or 2.5 microM significantly reduced the growth rates of pure cultures, whereas AcpP PPMO or either Scr PPMO had no effect. However, the viable cell count was significantly reduced at either concentration of 3+Pip-AcpP PPMO or AcpP PPMO, but not with either Scr PPMO. In other experiments, macrophages were infected intracellularly with S. enterica and treated with 3 microM 3+Pip-AcpP PPMO. Intracellular bacteria were reduced >99% with 3+Pip-AcpP PPMO, whereas intracellular bacteria increased 3 orders of magnitude in untreated or Scr PPMO-treated cultures. We conclude that either AcpP PPMO or 3+Pip-AcpP PPMO inhibited growth of S. enterica in pure culture and that 3+Pip-AcpP PPMO reduced intracellular viability of S. enterica in macrophages.
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Ricci V, Piddock LJV. Ciprofloxacin selects for multidrug resistance in Salmonella enterica serovar Typhimurium mediated by at least two different pathways. J Antimicrob Chemother 2009; 63:909-16. [PMID: 19270312 DOI: 10.1093/jac/dkp054] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES The aim of this study was to understand the role of ramA in conferring multidrug resistance (MDR) in Salmonella enterica serovar Typhimurium. METHODS Two phenotypically distinct isogenic MDR laboratory mutants derived from Salmonella Typhimurium SL1344 and three human clinical isolates from a patient that failed antibiotic therapy, including with ciprofloxacin, were investigated for the cause of MDR. MICs were determined by agar dilution and efflux activity assessed by monitoring the accumulation of Hoechst 33342. The combination of specific genes and MDR was assessed by inactivation, and complementation RT-PCR was used to assess gene expression and DNA sequencing to identify mutations within genes of interest. RESULTS Mutation in ramR and the consequent over-production of ramA and acrB were revealed in one laboratory mutant selected with ciprofloxacin and this was associated with cyclohexane tolerance. Complementation of SL1344 ramR::aph with pUC19 ramR(mutant) conferred MDR and cyclohexane tolerance. However, analysis of a second ciprofloxacin-selected MDR mutant, which was susceptible to cyclohexane, revealed no mutation in ramR or altered expression of marA, soxS or rob. There was a mutation in ramR in both the pre- and post-therapy clinical isolates and no difference between the isolates in the level of expression of ramA. CONCLUSIONS These data show that ciprofloxacin exposure can select for mutations within ramR and consequently mediate MDR. These data also indicate that there is at least one further unidentified gene in addition to marA, soxS, rob and ramA that confers MDR in S. enterica.
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Phan MD, Kidgell C, Nair S, Holt KE, Turner AK, Hinds J, Butcher P, Cooke FJ, Thomson NR, Titball R, Bhutta ZA, Hasan R, Dougan G, Wain J. Variation in Salmonella enterica serovar typhi IncHI1 plasmids during the global spread of resistant typhoid fever. Antimicrob Agents Chemother 2009; 53:716-27. [PMID: 19015365 PMCID: PMC2630618 DOI: 10.1128/aac.00645-08] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 07/22/2008] [Accepted: 10/13/2008] [Indexed: 11/20/2022] Open
Abstract
A global collection of plasmids of the IncHI1 incompatibility group from Salmonella enterica serovar Typhi were analyzed by using a combination of DNA sequencing, DNA sequence analysis, PCR, and microarrays. The IncHI1 resistance plasmids of serovar Typhi display a backbone of conserved gene content and arrangement, within which are embedded preferred acquisition sites for horizontal DNA transfer events. The variable regions appear to be preferred acquisition sites for DNA, most likely through composite transposition, which is presumably driven by the acquisition of resistance genes. Plasmid multilocus sequence typing, a molecular typing method for IncHI1 plasmids, was developed using variation in six conserved loci to trace the spread of these plasmids and to elucidate their evolutionary relationships. The application of this method to a collection of 36 IncHI1 plasmids revealed a chronological clustering of plasmids despite their difference in geographical origins. Our findings suggest that the predominant plasmid types present after 1993 have not evolved directly from the earlier predominant plasmid type but have displaced them. We propose that antibiotic selection acts to maintain resistance genes on the plasmid, but there is also competition between plasmids encoding the same resistance phenotype.
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Affiliation(s)
- Minh-Duy Phan
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
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Sen B, Bhattacharya M, Niyogi SK. In vitro activity of cefpodoxime, an expanded-spectrum cephalosporin, against Salmonella enterica serotype typhi. Antimicrob Agents Chemother 2008; 52:802-3. [PMID: 18039924 PMCID: PMC2224739 DOI: 10.1128/aac.00867-07] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Wilson ME, Schwartz E. Fever. TRAVEL MEDICINE 2008. [PMCID: PMC7152452 DOI: 10.1016/b978-0-323-03453-1.10053-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Le TAH, Fabre L, Roumagnac P, Grimont PAD, Scavizzi MR, Weill FX. Clonal expansion and microevolution of quinolone-resistant Salmonella enterica serotype typhi in Vietnam from 1996 to 2004. J Clin Microbiol 2007; 45:3485-92. [PMID: 17728470 PMCID: PMC2168509 DOI: 10.1128/jcm.00948-07] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Salmonella enterica serotype Typhi clinical isolates (n = 91) resistant to nalidixic acid (Nal(r)) were collected from sporadic cases and minor outbreaks throughout Vietnam between 1996 and 2004. These isolates were typed and compared by four methods: Vi phage typing, PstI ribotyping, XbaI and SpeI pulsed-field gel electrophoresis (PFGE), and single-nucleotide polymorphism (SNP) analysis. The results indicated that 65% of the isolates were not typeable by Vi phage typing. In contrast, the ribotyping and, with more accuracy, the SNP analysis methods indicated that all Nal(r) isolates belonged to a single clone (ribotype 3a, haplotype H58) that was found previously and that largely consisted of plasmid-encoded multidrug-resistant serotype Typhi isolates. PFGE demonstrated the occurrence of microevolution within this clone. We identified two major combined PFGE profiles: X1-S1 and X3-S6. X3-S6 predominated between 1996 and 2002 but was replaced by X1-S1 after 2002. Nevertheless, PFGE, with a Simpson's index of 0.78, was not considered an optimal discriminatory method for investigating typhoid fever outbreaks in Vietnam. The rate of quinolone resistance increased and the rate of multidrug resistance decreased during the study period. From 2002 to 2004, 80.6% of the isolates from South Vietnam were resistant only to Nal. The mechanism of Nal resistance in most of the isolates (94%) was a mutation in the quinolone resistance-determining chromosomal region of gyrA that led to the amino acid substitution Ser83Phe. No plasmid-located qnrA, qnrB, or qnrS was detected.
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Affiliation(s)
- Thi Anh Hong Le
- Centre National de Référence des Salmonella, Unité de Biodiversité des Bactéries Pathogènes Emergentes, Institut Pasteur, 28 rue du Docteur Roux, 75724, Paris Cedex 15, France
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Cooke FJ, Day M, Wain J, Ward LR, Threlfall EJ. Cases of typhoid fever imported into England, Scotland and Wales (2000–2003). Trans R Soc Trop Med Hyg 2007; 101:398-404. [PMID: 17014877 DOI: 10.1016/j.trstmh.2006.07.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 07/28/2006] [Accepted: 07/28/2006] [Indexed: 11/23/2022] Open
Abstract
Although typhoid fever is no longer endemic in most of the developed world, it remains a major infectious disease in less developed regions and imported cases continue to occur in returning travellers, immigrants or migrant workers. We analysed all 692 isolates of Salmonella enterica subspecies enterica serovar Typhi from cases in England, Scotland and Wales that were sent to the Laboratory of Enteric Pathogens at the Health Protection Agency, Centre for Infections, London, UK between 2000 and 2003. The country of acquisition was known for 416 isolates (60%), and the majority of these (70%) came from India or Pakistan. Overall, 24 countries were listed, mainly in Asia and Africa. A total of 48 phage types were detected, 41% of which were Vi-phage type E1. Antimicrobial susceptibility testing revealed that 22% of isolates were multidrug resistant (MDR) (defined as resistance to chloramphenicol, ampicillin and co-trimoxazole) and 39% were quinolone resistant. A significant number of isolates (n=49) were sensitive to nalidixic acid by disk test but exhibited low-level ciprofloxacin resistance, suggesting a novel mechanism of resistance and reinforcing the need for minimum inhibitory concentration determination. Overall, 13% of isolates were both MDR and likely to show a poor response to a fluoroquinolone. A third-generation cephalosporin (e.g. ceftriaxone) should be considered as empirical therapy in regions of the Indian subcontinent where resistance is now at high levels as well as in patients returning from these areas. This study helps to describe the epidemiology of antimicrobial drug resistance in typhoid fever.
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Affiliation(s)
- Fiona J Cooke
- Health Protection Agency, Centre for Infections, 61 Colindale Avenue, London, UK
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Holt KE, Thomson NR, Wain J, Phan MD, Nair S, Hasan R, Bhutta ZA, Quail MA, Norbertczak H, Walker D, Dougan G, Parkhill J. Multidrug-resistant Salmonella enterica serovar paratyphi A harbors IncHI1 plasmids similar to those found in serovar typhi. J Bacteriol 2007; 189:4257-64. [PMID: 17384186 PMCID: PMC1913411 DOI: 10.1128/jb.00232-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovars Typhi and Paratyphi A cause systemic infections in humans which are referred to as enteric fever. Multidrug-resistant (MDR) serovar Typhi isolates emerged in the 1980s, and in recent years MDR serovar Paratyphi A infections have become established as a significant problem across Asia. MDR in serovar Typhi is almost invariably associated with IncHI1 plasmids, but the genetic basis of MDR in serovar Paratyphi A has remained predominantly undefined. The DNA sequence of an IncHI1 plasmid, pAKU_1, encoding MDR in a serovar Paratyphi A strain has been determined. Significantly, this plasmid shares a common IncHI1-associated DNA backbone with the serovar Typhi plasmid pHCM1 and an S. enterica serovar Typhimurium plasmid pR27. Plasmids pAKU_1 and pHCM1 share 14 antibiotic resistance genes encoded within similar mobile elements, which appear to form a 24-kb composite transposon that has transferred as a single unit into different positions into their IncHI1 backbones. Thus, these plasmids have acquired similar antibiotic resistance genes independently via the horizontal transfer of mobile DNA elements. Furthermore, two IncHI1 plasmids from a Vietnamese isolate of serovar Typhi were found to contain features of the backbone sequence of pAKU_1 rather than pHCM1, with the composite transposon inserted in the same location as in the pAKU_1 sequence. Our data show that these serovar Typhi and Paratyphi A IncHI1 plasmids share highly conserved core DNA and have acquired similar mobile elements encoding antibiotic resistance genes in past decades.
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Affiliation(s)
- Kathryn E Holt
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
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Doyle M, Fookes M, Ivens A, Mangan MW, Wain J, Dorman CJ. An H-NS-like stealth protein aids horizontal DNA transmission in bacteria. Science 2007; 315:251-2. [PMID: 17218529 DOI: 10.1126/science.1137550] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Sfh protein is encoded by self-transmissible plasmids involved in human typhoid and is closely related to the global regulator H-NS. We have found that Sfh provides a stealth function that allows the plasmids to be transmitted to new bacterial hosts with minimal effects on their fitness. Introducing the plasmid without the sfh gene imposes a mild H-NS(-) phenotype and a severe loss of fitness due to titration of the cellular pool of H-NS by the A+T-rich plasmid. This stealth strategy seems to be used widely to aid horizontal DNA transmission and has important implications for bacterial evolution.
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Affiliation(s)
- Marie Doyle
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland.
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41
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Dutta S, Sur D, Manna B, Sen B, Deb AK, Deen JL, Wain J, Von Seidlein L, Ochiai L, Clemens JD, Kumar Bhattacharya S. Evaluation of new-generation serologic tests for the diagnosis of typhoid fever: data from a community-based surveillance in Calcutta, India. Diagn Microbiol Infect Dis 2006; 56:359-65. [PMID: 16938421 DOI: 10.1016/j.diagmicrobio.2006.06.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 06/28/2006] [Accepted: 06/29/2006] [Indexed: 11/30/2022]
Abstract
Although typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi, rapid and simple diagnostic serologic tests would be useful in developing countries. We examined the performance of Widal test in a community field site and compared it with Typhidot and Tubex tests for diagnosis of typhoid fever. Blood samples were collected from 6697 patients with fever for > or =3 days for microscopy, culture, and serologic testing and from randomly selected 172 consenting healthy individuals to assess the baseline Widal anti-Typhi O lipopolysaccharide antibody (anti-TO) and anti-Typhi H flagellar antibody (anti-TH) titers. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 3 serologic tests were calculated using culture-confirmed typhoid fever cases as "true positives" and paratyphoid fever and malaria cases as "true negatives". Comparing cutoff values for the Widal test, an anti-TO titer of 1/80 was optimal with 58% sensitivity, 85% specificity, 69% PPV, and 77% NPV. Sensitivity was increased to 67% when the Widal test was done on the 5th day of illness and thereafter. The sensitivity, specificity, PPV, and NPV of Typhidot and Tubex were not better than Widal test. There is a need for more efficient rapid diagnostic test for typhoid fever especially during the acute stage of the disease. Until then, culture remains the method of choice.
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Affiliation(s)
- Shanta Dutta
- National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme XM, Beliaghata, P.O. Box 177, Calcutta 700010, India
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Leplae R, Lima-Mendez G, Toussaint A. A first global analysis of plasmid encoded proteins in the ACLAME database. FEMS Microbiol Rev 2006; 30:980-94. [PMID: 17064288 DOI: 10.1111/j.1574-6976.2006.00044.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Many plasmids are mobile genetic elements (MGEs) and, as other members of that group of DNA entities, their genomes display a mosaic and combinatorial structure, making their classification extremely difficult. As other MGEs, plasmids play a major role in horizontal transfer of genetic materials and genome reorganization. Yet, the full impact of such phenomenon on major properties of the host cell, such as pathogenicity, the ability to use new carbon sources or resistance to antibiotics, remains to be fully assessed. More and more complete plasmid genome sequences are available. However, in the absence of standards for storing plasmid sequence data and annotating genes and gene products on sequenced plasmid genomes, the resulting information remains rather limited. Using 503 sequenced plasmids organized in the ACLAME database, we discuss how, by structuring information on the genomes, their host and the proteins they code for, one can gain access to either global or more detailed analysis of the plasmid sequence information, as illustrated by a network representation of the relationships between plasmids.
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Affiliation(s)
- Raphaël Leplae
- SCMBB, Université Libre de Bruxelles, Bvd du Triomphe, Bruxelles, Belgium.
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Doyle M, Dorman CJ. Reciprocal transcriptional and posttranscriptional growth-phase-dependent expression of sfh, a gene that encodes a paralogue of the nucleoid-associated protein H-NS. J Bacteriol 2006; 188:7581-91. [PMID: 16936022 PMCID: PMC1636274 DOI: 10.1128/jb.00685-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The IncHI1 self-transmissible plasmid pSf-R27 from Shigella flexneri 2a strain 2457T harbors sfh, a gene that codes for a protein with strong amino acid sequence homology to the global transcription regulator and nucleoid-associated protein H-NS and to its paralogue, StpA. Previously, we discovered that the expression of sfh mRNA is growth phase dependent such that in cultures growing in Lennox broth at 37 degrees C, the transcript is readily detectable in the early stages of exponential growth but is not detectable at the onset of stationary phase. In contrast, the Sfh protein is poorly expressed in early-exponential growth when sfh mRNA is abundant whereas it is expressed to a high level in early stationary phase, when sfh transcript expression is low (P. Deighan, C. Beloin, and C. J. Dorman, Mol. Microbiol. 48:1401-1416, 2003). This unusual pattern of reciprocal mRNA and protein expression is not due to growth phase-dependent effects on either mRNA or protein stability, nor is it due to the known abilities of the Sfh, StpA, and H-NS proteins to influence sfh gene expression. Instead, our data point to a blockade of sfh mRNA translation in early-exponential growth that is relieved as the culture enters the stationary phase of growth. Replacing the 5' end and translation initiation signals of the sfh mRNA with heterologous sequences did not alter the growth phase-dependent expression of the Sfh protein, suggesting that growth phase control of translation is intrinsic to another component of the message.
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Affiliation(s)
- Marie Doyle
- Department of Microbiology, Moyne Institute of Preventive Medicine, University of Dublin, Trinity College, Dublin 2, Ireland
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Maskey AP, Day JN, Phung QT, Thwaites GE, Campbell JI, Zimmerman M, Farrar JJ, Basnyat B. Salmonella enterica Serovar Paratyphi A and S. enterica Serovar Typhi Cause Indistinguishable Clinical Syndromes in Kathmandu, Nepal. Clin Infect Dis 2006; 42:1247-53. [PMID: 16586383 DOI: 10.1086/503033] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Accepted: 01/11/2006] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Enteric fever is a major global problem. Emergence of antibacterial resistance threatens to render current treatments ineffective. There is little research or public health effort directed toward Salmonella enterica serovar Paratyphi A, because it is assumed to cause less severe enteric fever than does S. enterica serovar Typhi. There are few data on which to base this assumption, little is known of the serovar's antibacterial susceptibilities, and there is no readily available tolerable vaccination. METHODS A prospective study was conducted of 609 consecutive cases of enteric fever (confirmed by blood culture) to compare the clinical phenotypes and antibacterial susceptibilities in S. Typhi and S. Paratyphi A infections. Variables independently associated with either infection were identified to develop a diagnostic rule to distinguish the infections. All isolates were tested for susceptibility to antibacterials. RESULTS Six hundred nine patients (409 with S. Typhi infection and 200 with S. Paratyphi A infection) presented during the study period. The infections were clinically indistinguishable and had equal severity. Nalidixic acid resistance, which predicts a poor response to fluoroquinolone treatment, was extremely common (75.25% of S. Paratyphi A isolates and 50.5% of S. Typhi isolates; P < .001). S. Paratyphi A was more likely to be resistant to ofloxacin (3.6% vs. 0.5%; P = .007) or to have intermediate susceptibility to ofloxacin (28.7% vs. 1.8%; P < .001) or ciprofloxacin (39.4% vs. 8.2%; P < .001). MICs for S. Paratyphi A were higher than for S. Typhi (MIC of ciprofloxacin, 0.75 vs. 0.38 microg/mL [P < .001]; MIC of ofloxacin, 2.0 vs. 0.75 microg/mL [P < .001]). CONCLUSIONS The importance of S. Paratyphi A has been underestimated. Infection is common, the agent causes disease as severe as that caused by S. Typhi and is highly likely to be drug resistant. Drug resistance and lack of effective vaccination suggest that S. Paratyphi A infection may become a major world health problem.
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Affiliation(s)
- Ashish P Maskey
- Patan Hospital, Lagankhel, Lalitpur, Bagmati, Kathmandu, Nepal
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45
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Frye JG, Jesse T, Long F, Rondeau G, Porwollik S, McClelland M, Jackson CR, Englen M, Fedorka-Cray PJ. DNA microarray detection of antimicrobial resistance genes in diverse bacteria. Int J Antimicrob Agents 2006; 27:138-51. [PMID: 16427254 DOI: 10.1016/j.ijantimicag.2005.09.021] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 09/17/2005] [Indexed: 11/26/2022]
Abstract
High throughput genotyping is essential for studying the spread of multiple antimicrobial resistance. A test oligonucleotide microarray designed to detect 94 antimicrobial resistance genes was constructed and successfully used to identify antimicrobial resistance genes in control strains. The microarray was then used to assay 51 distantly related bacteria, including Gram-negative and Gram-positive isolates, resulting in the identification of 61 different antimicrobial resistance genes in these bacteria. These results were consistent with their known gene content and resistance phenotypes. Microarray results were confirmed by polymerase chain reaction and Southern blot analysis. These results demonstrate that this approach could be used to construct a microarray to detect all sequenced antimicrobial resistance genes in nearly all bacteria.
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Affiliation(s)
- Jonathan G Frye
- Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. Department of Agriculture, Agriculture Research Service, Richard B. Russell Research Center, 950 College Station Road, Athens, GA 30605, USA.
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Acosta CJ, Galindo CM, Ali M, Elyazeed RA, Ochiai RL, Danovaro-Holliday MC, Page AL, Thiem VD, Jin Y, Park JK, Lee H, Puri MK, Ivanoff B, Agtini MD, Soeharno R, Simanjuntak CH, Punjabi NH, Canh DG, Sur D, Nizami Q, Manna B, Bai-qing D, Anh DD, Honghui Y, Bhattacharya SK, Bhutta Z, Trach DD, Xu ZY, Pang T, Donner A, Clemens JD. A multi-country cluster randomized controlled effectiveness evaluation to accelerate the introduction of Vi polysaccharide typhoid vaccine in developing countries in Asia: rationale and design. Trop Med Int Health 2006; 10:1219-28. [PMID: 16359401 DOI: 10.1111/j.1365-3156.2005.01517.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phase-III vaccine efficacy trials typically employ individually randomized designs intended to ensure that measurements of vaccine protective efficacy reflect only direct vaccine effects. As a result, decisions about introducing newly licensed vaccines into public health programmes often fail to consider the substantially greater protection that may occur when a vaccine is deployed in public health programmes, due to the combination of direct plus indirect vaccine protective effects. Vaccine total protection can be better evaluated with cluster randomized trials. Such a design was considered to generate policy relevant data to accelerate the rationale introduction of the licensed typhoid fever Vi polysaccharide (PS) vaccine in Asia by the Diseases of the Most Impoverished (DOMI) typhoid fever programme. The DOMI's programme multi-country study is one of the largest cluster randomized vaccine trials ever mounted in Asia, which includes approximately 200,000 individuals. Its main objective is to determine the effectiveness of a licensed Vi PS vaccine. The rationale and design of this study are discussed. Preliminary results are presented that determined the final planning of the trial before immunization. Important methodological and practical issues regarding vaccine cluster randomized designs are illustrated.
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Alonso G, Baptista K, Ngo T, Taylor DE. Transcriptional organization of the temperature-sensitive transfer system from the IncHI1 plasmid R27. Microbiology (Reading) 2005; 151:3563-3573. [PMID: 16272379 DOI: 10.1099/mic.0.28256-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
One of the characteristic features of IncHI1 plasmids is a thermosensitive process of conjugation, which is optimal between 22 °C and 30 °C but inhibited at 37 °C. R27, the prototypical IncHI1 plasmid, contains transfer genes clustered in two regions of the plasmid, Tra1 and Tra2. In the present study, transcriptional analyses of thetragenes were undertaken at both 30 °C and 37 °C. Screening of 38tragenes showed thattragenes are transcriptionally linked in six operons, three in each Tra region. RT-PCR analysis showed that gene expression was reduced at 37 °C relative to that observed at 30 °C. The transcription start sites of the six transcripts were identified, promoters and upstream regions were cloned, and transcription was tested at both temperatures. In cells grown at 37 °C, in the presence of R27, the promoters were inhibited, except for promoters of the H operon and AN operon. Conditions that influenced DNA topology, such as osmolarity, anaerobiosis, quorum sensing and acidity, showed no significant influence on transfer frequency. These results should facilitate future understanding of the basis of temperature-sensitive transfer in this large conjugative plasmid.
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Affiliation(s)
- Guillermina Alonso
- Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela. Caracas, Venezuela
| | - Kelly Baptista
- Department of Medical Microbiology and Immunology, 1-63 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Trinh Ngo
- Department of Medical Microbiology and Immunology, 1-63 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Diane E Taylor
- Department of Medical Microbiology and Immunology, 1-63 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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Acosta CJ, Galindo CM, Deen JL, Ochiai RL, Lee HJ, von Seidlein L, Carbis R, Clemens JD. Vaccines against cholera, typhoid fever and shigellosis for developing countries. Expert Opin Biol Ther 2005; 4:1939-51. [PMID: 15571456 DOI: 10.1517/14712598.4.12.1939] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Enteric diseases, such as cholera, typhoid fever and shigellosis, still produce a significant burden, especially among the poor in countries where these illnesses are endemic. Older-generation, parenteral, whole-cell vaccines against cholera and typhoid fever were abandoned in many countries as public health tools because of problems with insufficient protection and/or inadequate safety profiles. Modern-generation licensed vaccines are available for cholera and typhoid fever, but are not widely used by those in greatest need. A number of experimental candidates exist for all three diseases. Future research should focus on generating the evidence necessary to obtain a consensus on the deployment of existing vaccines against cholera and typhoid fever, and on clinical evaluation of pipeline vaccine candidates against all three diseases.
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Affiliation(s)
- C J Acosta
- International Vaccine Institute, Seoul National University Research Park, San 4-8 Bongcheon-7-dong, Kwanak-Ku, Seoul, Korea 151-818.
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