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Yamaguchi M, Uchihashi T, Kawabata S. Hybrid sequence-based analysis reveals the distribution of bacterial species and genes in the oral microbiome at a high resolution. Biochem Biophys Rep 2024; 38:101717. [PMID: 38708423 PMCID: PMC11066573 DOI: 10.1016/j.bbrep.2024.101717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/14/2024] [Accepted: 04/19/2024] [Indexed: 05/07/2024] Open
Abstract
Bacteria in the oral microbiome are poorly identified owing to the lack of established culture methods for them. Thus, this study aimed to use culture-free analysis techniques, including bacterial single-cell genome sequencing, to identify bacterial species and investigate gene distribution in saliva. Saliva samples from the same individual were classified as inactivated or viable and then analyzed using 16S rRNA sequencing, metagenomic shotgun sequencing, and bacterial single-cell sequencing. The results of 16S rRNA sequencing revealed similar microbiota structures in both samples, with Streptococcus being the predominant genus. Metagenomic shotgun sequencing showed that approximately 80 % of the DNA in the samples was of non-bacterial origin, whereas single-cell sequencing showed an average contamination rate of 10.4 % per genome. Single-cell sequencing also yielded genome sequences for 43 out of 48 wells for the inactivated samples and 45 out of 48 wells for the viable samples. With respect to resistance genes, four out of 88 isolates carried cfxA, which encodes a β-lactamase, and four isolates carried erythromycin resistance genes. Tetracycline resistance genes were found in nine bacteria. Metagenomic shotgun sequencing provided complete sequences of cfxA, ermF, and ermX, whereas other resistance genes, such as tetQ and tetM, were detected as fragments. In addition, virulence factors from Streptococcus pneumoniae were the most common, with 13 genes detected. Our average nucleotide identity analysis also suggested five single-cell-isolated bacteria as potential novel species. These data would contribute to expanding the oral microbiome data resource.
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Affiliation(s)
- Masaya Yamaguchi
- Bioinformatics Research Unit, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
- Department of Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
- Bioinformatics Center, Research Institute for Microbial Diseases, Osaka University, Japan
- Center for Infectious Diseases Education and Research, Osaka University, Japan
| | - Toshihiro Uchihashi
- Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Shigetada Kawabata
- Department of Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
- Center for Infectious Diseases Education and Research, Osaka University, Japan
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Summer M, Ali S, Tahir HM, Abaidullah R, Fiaz U, Mumtaz S, Fiaz H, Hassan A, Mughal TA, Farooq MA. Mode of Action of Biogenic Silver, Zinc, Copper, Titanium and Cobalt Nanoparticles Against Antibiotics Resistant Pathogens. J Inorg Organomet Polym Mater 2024; 34:1417-1451. [DOI: 10.1007/s10904-023-02935-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/02/2023] [Indexed: 08/04/2024]
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Warda K, Amari S, Boureddane M, Elkamouni Y, Arsalane L, Zouhair S, Bouskraoui M. Changes in pneumococcal serotypes distribution and penicillin resistance in healthy children five years after generalization of PCV10. Heliyon 2024; 10:e25741. [PMID: 38380016 PMCID: PMC10877248 DOI: 10.1016/j.heliyon.2024.e25741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/11/2024] [Accepted: 02/01/2024] [Indexed: 02/22/2024] Open
Abstract
Objective Streptococcus pneumoniae (S. pneumoniae) nasopharyngeal carriage has significantly decreased after the generalization of pneumococcal vaccination worldwide. This study sought to investigate changes in S. pneumoniae carriage rates, serotype distribution and penicillin non-susceptibility following the generalization of 10-valent pneumococcal conjugate vaccine. Methods A prospective study was conducted in Marrakesh, Morocco, between 2017 and 2018, among healthy children attending vaccination centers. We collected nasopharyngeal swabs and questionnaire data for each child. Using univariate logistic regression, we analyzed the association between S. pneumoniae carriage and various risk factors. Comparisons of serotype diversity and penicillin resistance between 2017 and 2018 and the period before introduction of vaccination (2008-2009, n = 660) were performed using Simpson index and the chi-squared test, respectively. Results During 2017-2018, 515 children aged between 6 and 36 months participated. The S. pneumoniae carriage rate was 43.3%. Looking at the distribution serotypes, the rate of PCV10 serotypes rate was only 9.6%. Among non-vaccine serotypes, an increase in serotypes 6C/6D (22; 14%), 19B/19C (17; 10.8%), and 15B/15C (11; 7%) was observed. A particular increase in serotype diversity was also observed after the generalization of PCV10 (p < 0.001). S. pneumoniae non-susceptible to penicillin decreased, reaching a rate of 26.6% in 2017-2018. Conclusion The significant change in S. pneumoniae carriage, serotype distribution, and penicillin resistance highlights the effectiveness of the pneumococcal conjugate vaccine among children in Marrakesh, Morocco.
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Affiliation(s)
- Karima Warda
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
| | - Sara Amari
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
| | - Majda Boureddane
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
| | - Youssef Elkamouni
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
- Laboratory of Microbiology-Virology and Molecular Biology, Avicenna Military Hospital, Marrakesh, Morocco
| | - Lamiae Arsalane
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
- Laboratory of Microbiology-Virology and Molecular Biology, Avicenna Military Hospital, Marrakesh, Morocco
| | - Said Zouhair
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
- Laboratory of Microbiology-Virology and Molecular Biology, Avicenna Military Hospital, Marrakesh, Morocco
| | - Mohammed Bouskraoui
- Laboratory of Microbiology and Virology, Cadi Ayad University, Marrakesh, Morocco
- Department of Pediatrics, Mohamed VI University Hospital Center, Marrakesh, Morocco
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Massacci FR, Cucco L, Panicciá M, Luppi A, Albini E, Peruzzo A, Ferroni L, Ustulin M, Orsini M, Magistrali CF. Streptococcus suis serotype 9 in Italy: genomic insights into high-risk clones with emerging resistance to penicillin. J Antimicrob Chemother 2024; 79:403-411. [PMID: 38153239 PMCID: PMC10832592 DOI: 10.1093/jac/dkad395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 12/06/2023] [Indexed: 12/29/2023] Open
Abstract
BACKGROUND Streptococcus suis is an important pig pathogen and an emerging zoonotic agent. In a previous study, we described a high proportion of penicillin-resistant serotype 9 S. suis (SS9) isolates on pig farms in Italy. OBJECTIVES We hypothesized that resistance to penicillin emerged in some SS9 lineages characterized by substitutions at the PBPs, contributing to the successful spread of these lineages in the last 20 years. METHODS Sixty-six SS9 isolates from cases of streptococcosis in pigs were investigated for susceptibility to penicillin, ceftiofur and ampicillin. The isolates were characterized for ST, virulence profile, and antimicrobial resistance genes through WGS. Multiple linear regression models were employed to investigate the associations between STs, year of isolation, substitutions at the PBPs and an increase in MIC values to β-lactams. RESULTS MIC values to penicillin increased by 4% each year in the study period. Higher MIC values for penicillin were also positively associated with ST123, ST1540 and ST1953 compared with ST16. The PBP sequences presented a mosaic organization of blocks. Within the same ST, substitutions at the PBPs were generally more frequent in recent isolates. Resistance to penicillin was driven by substitutions at PBP2b, including K479T, D512E and K513E, and PBP2x, including T551S, while reduced susceptibility to ceftiofur and ampicillin were largely dependent on substitutions at PBP2x. CONCLUSIONS Here, we identify the STs and substitutions at the PBPs responsible for increased resistance of SS9 to penicillin on Italian pig farms. Our data highlight the need for monitoring the evolution of S. suis in the coming years.
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Affiliation(s)
| | - Lucilla Cucco
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche ‘Togo Rosati’, Perugia, Italy
| | - Marta Panicciá
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche ‘Togo Rosati’, Perugia, Italy
| | - Andrea Luppi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Parma, Italy
| | - Elisa Albini
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche ‘Togo Rosati’, Perugia, Italy
| | - Arianna Peruzzo
- Istituto Zooprofilattico Sperimentale delle Venezie, Padova, Italy
| | - Laura Ferroni
- Istituto Zooprofilattico Sperimentale dell’Umbria e delle Marche ‘Togo Rosati’, Perugia, Italy
| | - Martina Ustulin
- Istituto Zooprofilattico Sperimentale delle Venezie, Padova, Italy
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Mokaya J, Mellor KC, Murray GGR, Kalizang’oma A, Lekhuleni C, Zar HJ, Nicol MP, McGee L, Bentley SD, Lo SW, Dube F. Genomic epidemiology of Streptococcus pneumoniae serotype 16F lineages. Microb Genom 2023; 9:001123. [PMID: 37917136 PMCID: PMC10711320 DOI: 10.1099/mgen.0.001123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 10/09/2023] [Indexed: 11/03/2023] Open
Abstract
Due to the emergence of non-vaccine serotypes in vaccinated populations, Streptococcus pneumoniae remains a major global health challenge despite advances in vaccine development. Serotype 16F is among the predominant non-vaccine serotypes identified among vaccinated infants in South Africa (SA). To characterize lineages and antimicrobial resistance in 16F isolates obtained from South Africa and place the local findings in a global context, we analysed 10 923 S. pneumoniae carriage isolates obtained from infants recruited as part of a broader SA birth cohort. We inferred serotype, resistance profile for penicillin, chloramphenicol, cotrimoxazole, erythromycin and tetracycline, and global pneumococcal sequence clusters (GPSCs) from genomic data. To ensure global representation, we also included S. pneumoniae carriage and disease isolates from the Global Pneumococcal Sequencing (GPS) project database (n=19 607, collected from 49 countries across 5 continents, 1995-2018, accessed 17 March 2022). Nine per cent (934/10923) of isolates obtained from infants in the Drakenstein community in SA and 2 %(419/19607) of genomes in the GPS dataset were serotype 16F. Serotype 16F isolates were from 28 different lineages of S. pneumoniae, with GPSC33 and GPSC46 having the highest proportion of serotype 16F isolates at 26 % (346/1353) and 53 % (716/1353), respectively. Serotype 16F isolates were identified globally, but most isolates were collected from Africa. GPSC33 was associated with carriage [OR (95 % CI) 0.24 (0.09-0.66); P=0.003], while GPSC46 was associated with disease [OR (95 % CI) 19.9 (2.56-906.50); P=0.0004]. Ten per cent (37/346) and 15 % (53/346) of isolates within GPSC33 had genes associated with resistance to penicillin and co-trimoxazole, respectively, and 18 % (128/716) of isolates within GPSC46 had genes associated with resistance to co-trimoxazole. Resistant isolates formed genetic clusters, which may suggest emerging resistant lineages. Serotype 16F lineages were common in southern Africa. Some of these lineages were associated with disease and resistance to penicillin and cotrimoxazole. We recommend continuous genomic surveillance to determine the long-term impact of serotype 16F lineages on vaccine efficacy and antimicrobial therapy globally. Investing in vaccine strategies that offer protection over a wide range of serotypes/lineages remains essential. This paper contains data hosted by Microreact.
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Affiliation(s)
- Jolynne Mokaya
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, UK
| | - Kate C. Mellor
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, UK
| | - Gemma G. R. Murray
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, UK
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Akuzike Kalizang’oma
- NIHR Mucosal Pathogens Research Unit, Research Department of Infection, Division of Infection and Immunity, University College London, London, UK
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - Cebile Lekhuleni
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, a division of the National Health Laboratory Service, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Heather J. Zar
- Department of Paediatrics and Child Health, Red Cross War Memorial Childrenʼs Hospital and SA-MRC unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa
| | - Mark P. Nicol
- Marshall Centre, School of Biomedical Sciences, University of Western Australia, School of Biomedical Sciences, Perth, ACT, Australia
| | - Lesley McGee
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Stephanie W. Lo
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, UK
- Milner Centre for Evolution, Life Sciences Department, University of Bath, Bath, UK
| | - Felix Dube
- Department of Molecular and Cell Biology and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- School of Medicine, University of Lusaka, Lusaka, Zambia
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Mokaya J, Mellor KC, Murray GGR, Kalizang'oma A, Lekhuleni C, Zar HJ, Nicol MP, McGee L, Bentley SD, Lo SW, Dube F. Evidence of virulence and antimicrobial resistance in Streptococcus pneumoniae serotype 16F lineages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.25.554804. [PMID: 37693504 PMCID: PMC10491096 DOI: 10.1101/2023.08.25.554804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Introduction Due to the emergence of non-vaccine serotypes in vaccinated populations, Streptococcus pneumoniae remains a major global health challenge despite advances in vaccine development. Serotype 16F is among the predominant non-vaccine serotypes identified among vaccinated infants in South Africa (SA). Aim To characterise lineages and antimicrobial resistance in 16F isolates obtained from South Africa and placed the local findings in a global context. Methodology We analysed 10923 S. pneumoniae carriage isolates obtained from infants recruited as part of a broader SA birth cohort. We inferred serotype, resistance profile for penicillin, chloramphenicol, cotrimoxazole, erythromycin and tetracycline, and Global Pneumococcal Sequence Clusters (GPSCs) from genomic data. To ensure global representation, we also included S. pneumoniae carriage and disease isolates from the Global Pneumococcal Sequencing (GPS) project database (n=19,607, collected from 49 countries across five continents, years covered (1995 - 2018), accessed on 17 th March 2022). Results Nine percent (934/10923) of isolates obtained from infants in the Drakenstein community in SA and 2% (419/19607) of genomes in the GPS dataset were serotype 16F. Serotype 16F isolates were from 28 different lineages of S. pneumoniae, with GPSC33 and GPSC46 having the highest proportion of serotype 16F isolates at 26% (346/1353) and 53% (716/1353), respectively. Serotype 16F isolates were identified globally, however, most isolates were collected from Africa. GPSC33 was associated with carriage [OR (95% CI) 0.24 (0.09 - 0.66); p=0.003], while GPSC46 was associated with disease [OR (95% CI) 19.9 (2.56 - 906.50); p=0.0004]. 10% (37/346) and 15% (53/346) of isolates within GPSC33 had genes associated with resistance to penicillin and co-trimoxazole, respectively, and 18% (128/716) of isolates within GPSC46 had genes associated with resistance to co-trimoxazole. Resistant isolates formed genetic clusters which may suggest emerging resistant lineages. Discussion Serotype 16F lineages are common in Southern Africa. Some of these lineages are associated with disease, and resistance to penicillin and cotrimoxazole. We recommend continuous genomic surveillance to determine long term impact of serotype 16F lineages on vaccine efficacy and antimicrobial therapy globally. Investing in vaccine strategies that offer protection over a wide range of serotypes/lineages remains essential. DATA SUMMARY The sequencing reads for the genomes analysed have been deposited in the European Nucleotide Archive and the accession numbers for each isolate are listed in Supplementary Table1 . Phylogenetic tree of serotype 16F pneumococcal genomes and associated metadata are available for download and visualisation on the Microreact website: Phylogenies of seotype 16F, GPSC33 and GPSC46 are available on the Microreact serotype-16F , GPSC33 and GPSC46 , respectively. IMPACT STATEMENT This study shows that serotype 16F lineages are predominant in Southern Africa and are associated with disease and antimicrobial resistance. Although serotype 16F has been included in the newer formulation of the upcoming vaccine formulations of PCV21 and IVT-25, continuous surveillance to determine long term impact of serotype 16F lineages on vaccines and antimicrobial therapy remains essential.
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Mills RO, Abdullah MR, Akwetey SA, Sappor DC, Bolivar JA, Gámez G, van der Linden MPG, Hammerschmidt S. Molecular Characterization and Antibiotic Susceptibility of Non-PCV13 Pneumococcal Serotypes among Vaccinated Children in Cape Coast, Ghana. Microorganisms 2022; 10:microorganisms10102054. [PMID: 36296330 PMCID: PMC9609747 DOI: 10.3390/microorganisms10102054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022] Open
Abstract
Preventive strategies involving the use of pneumococcal conjugate vaccines (PCVs) are known to drastically reduce pneumococcal disease. However, PCV vaccination has been plagued with serotype replacement by non-PCV serotypes. In this study, we describe the prevalence and molecular characteristics of non-PCV13 serotypes (non-vaccine serotypes, NVTs) from pneumococcal carriage isolates obtained from children < 5 years old in Cape Coast, Ghana, after PCV introduction. The isolates were subjected to antibiotic susceptibility testing and multilocus sequence typing (MLST), and molecular techniques were used to detect the presence of virulence genes. Serotypes 11A, 13, 15B, 23B, and 34 formed the top five of the 93 NVT isolates. As such, 20 (21.5%), 49 (48.4%), and 70 (74.3%) isolates were non-susceptible to penicillin, tetracycline, and cotrimoxazole, respectively. Sixteen (17.2%) multidrug-resistant isolates were identified. However, non-susceptibility to ceftriaxone and erythromycin was low and all isolates were fully susceptible to levofloxacin, linezolid, and vancomycin. Whereas pcpA, pavB, lytA, and psrP genes were detected in nearly all serotypes, pilus islet genes were limited to serotypes 11A, 13, and 23B. MLST for predominant serotype 23B isolates revealed three known and seven novel sequence types (STs). ST172 and novel ST15111 were the most dominant and both STs were related to PMEN clone Columbia23F-26 (ST338). In conclusion, non-PCV13 serotype 23B was the most prevalent, with characteristics of rapid clonal expansion of ST172 and ST15111, which are related to international clones of the pneumococcus. Continuous monitoring of NVTs in Ghana is, therefore, essential, as they have the potential to cause invasive disease, show high antibiotic resistance, and attenuate the effects of PCV vaccination.
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Affiliation(s)
- Richael O. Mills
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17489 Greifswald, Germany
- Department of Biomedical Sciences, School of Allied Health Science, University of Cape Coast, Cape Coast PMB TF0494, Ghana
| | - Mohammed R. Abdullah
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17489 Greifswald, Germany
| | - Samuel A. Akwetey
- Department of Biomedical Sciences, School of Allied Health Science, University of Cape Coast, Cape Coast PMB TF0494, Ghana
- Department of Clinical Microbiology, School of Medicine, University of Development Studies, Tamale PMB TF0494, Ghana
| | - Dorcas C. Sappor
- Department of Medical Laboratory Sciences, School of Allied Health Sciences, University of Cape Coast, Cape Coast PMB TF0494, Ghana
| | - Johan A. Bolivar
- Genetics, Regeneration and Cancer (GRC), University Research Centre (SIU), University of Antioquia (UdeA), Medellín 050010, Colombia
- Basic and Applied Microbiology (MICROBA), School of Microbiology, University of Antioquia Medellin, Antioquia 050010, Colombia
| | - Gustavo Gámez
- Genetics, Regeneration and Cancer (GRC), University Research Centre (SIU), University of Antioquia (UdeA), Medellín 050010, Colombia
- Basic and Applied Microbiology (MICROBA), School of Microbiology, University of Antioquia Medellin, Antioquia 050010, Colombia
| | - Mark P. G. van der Linden
- German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17489 Greifswald, Germany
- Correspondence: ; Tel.: +49-(0)3834-420-5700
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Olsen RJ, Zhu L, Mangham RE, Faili A, Kayal S, Beres SB, Musser JM. A Chimeric Penicillin Binding Protein 2X Significantly Decreases in Vitro Beta-Lactam Susceptibility and Increases in Vivo Fitness of Streptococcus pyogenes. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:1397-1406. [PMID: 35843262 PMCID: PMC9552024 DOI: 10.1016/j.ajpath.2022.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
All tested strains of Streptococcus pyogenes (group A streptococcus, GAS) remain susceptible to penicillin. However, GAS strains with amino acid substitutions in penicillin-binding proteins that confer decreased susceptibility to beta-lactam antibiotics have been identified recently. This discovery raises concerns about emergence of beta-lactam antibiotic resistance in GAS. Whole genome sequencing recently identified GAS strains with a chimeric penicillin-binding protein 2X (PBP2X) containing a recombinant segment from Streptococcus dysgalactiae subspecies equisimilis (SDSE). To directly test the hypothesis that the chimeric SDSE-like PBP2X alters beta-lactam susceptibility in vitro and fitness in vivo, an isogenic mutant strain was generated and virulence assessed in a mouse model of necrotizing myositis. Compared with naturally occurring and isogenic strains with a wild-type GAS-like PBP2X, strains with the chimeric SDSE-like PBP2X had reduced susceptibility in vitro to nine beta-lactam antibiotics. In a mouse model of necrotizing myositis, the strains had identical fitness in the absence of benzylpenicillin treatment. However, mice treated intermittently with a subtherapeutic dose of benzylpenicillin had significantly more colony-forming units recovered from limbs infected with strains with the chimeric SDSE-like PBP2X. These results show that mutations such as the PBP2X chimera may result in significantly decreased beta-lactam susceptibility and increased fitness and virulence. Expanded diagnostic laboratory surveillance, genome sequencing, and molecular pathogenesis study of potentially emergent beta-lactam antibiotic resistance among GAS are needed.
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Affiliation(s)
- Randall J Olsen
- Laboratory of Molecular and Translational Human Infectious Disease Research, Center for Infectious Diseases, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas; Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York.
| | - Luchang Zhu
- Laboratory of Molecular and Translational Human Infectious Disease Research, Center for Infectious Diseases, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas; Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York
| | - Regan E Mangham
- Laboratory of Molecular and Translational Human Infectious Disease Research, Center for Infectious Diseases, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas
| | - Ahmad Faili
- Inserm, CIC 1414, Rennes, France; Faculty of Pharmacy, Université Rennes 1, Rennes, France; CHU de Rennes, Rennes, France
| | - Samer Kayal
- Inserm, CIC 1414, Rennes, France; CHU de Rennes, Rennes, France; Faculty of Medicine, Université Rennes 1, Rennes, France
| | - Stephen B Beres
- Laboratory of Molecular and Translational Human Infectious Disease Research, Center for Infectious Diseases, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas
| | - James M Musser
- Laboratory of Molecular and Translational Human Infectious Disease Research, Center for Infectious Diseases, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas; Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York
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D'Aeth JC, van der Linden MPG, McGee L, de Lencastre H, Turner P, Song JH, Lo SW, Gladstone RA, Sá-Leão R, Ko KS, Hanage WP, Breiman RF, Beall B, Bentley SD, Croucher NJ. The role of interspecies recombination in the evolution of antibiotic-resistant pneumococci. eLife 2021; 10:e67113. [PMID: 34259624 PMCID: PMC8321556 DOI: 10.7554/elife.67113] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/16/2021] [Indexed: 12/27/2022] Open
Abstract
Multidrug-resistant Streptococcus pneumoniae emerge through the modification of core genome loci by interspecies homologous recombinations, and acquisition of gene cassettes. Both occurred in the otherwise contrasting histories of the antibiotic-resistant S. pneumoniae lineages PMEN3 and PMEN9. A single PMEN3 clade spread globally, evading vaccine-induced immunity through frequent serotype switching, whereas locally circulating PMEN9 clades independently gained resistance. Both lineages repeatedly integrated Tn916-type and Tn1207.1-type elements, conferring tetracycline and macrolide resistance, respectively, through homologous recombination importing sequences originating in other species. A species-wide dataset found over 100 instances of such interspecific acquisitions of resistance cassettes and flanking homologous arms. Phylodynamic analysis of the most commonly sampled Tn1207.1-type insertion in PMEN9, originating from a commensal and disrupting a competence gene, suggested its expansion across Germany was driven by a high ratio of macrolide-to-β-lactam consumption. Hence, selection from antibiotic consumption was sufficient for these atypically large recombinations to overcome species boundaries across the pneumococcal chromosome.
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Affiliation(s)
- Joshua C D'Aeth
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College LondonLondonUnited Kingdom
| | - Mark PG van der Linden
- Institute for Medical Microbiology, National Reference Center for Streptococci, University Hospital RWTH AachenAachenGermany
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and PreventionAtlantaUnited States
| | - Herminia de Lencastre
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaOeirasPortugal
- Laboratory of Microbiology and Infectious Diseases, The Rockefeller UniversityNew YorkUnited States
| | - Paul Turner
- Cambodia Oxford Medical Research Unit, Angkor Hospital for ChildrenSiem ReapCambodia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Jae-Hoon Song
- Department of Molecular Cell Biology, Sungkyunkwan University School of MedicineSuwonRepublic of Korea
| | - Stephanie W Lo
- Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome CampusHinxtonUnited Kingdom
| | - Rebecca A Gladstone
- Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome CampusHinxtonUnited Kingdom
| | - Raquel Sá-Leão
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaOeirasPortugal
| | - Kwan Soo Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of MedicineSuwonRepublic of Korea
| | - William P Hanage
- Center for Communicable Disease Dynamics, Harvard T.H. Chan School of Public HealthBostonUnited States
| | - Robert F Breiman
- Department of Global Health, Rollins School of Public Health, Emory UniversityAtlantaUnited States
| | - Bernard Beall
- Respiratory Diseases Branch, Centers for Disease Control and PreventionAtlantaUnited States
| | - Stephen D Bentley
- Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome CampusHinxtonUnited Kingdom
| | - Nicholas J Croucher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College LondonLondonUnited Kingdom
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10
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Zeng HL, Aurell E. Inferring genetic fitness from genomic data. Phys Rev E 2021; 101:052409. [PMID: 32575265 DOI: 10.1103/physreve.101.052409] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 05/04/2020] [Indexed: 11/07/2022]
Abstract
The genetic composition of a naturally developing population is considered as due to mutation, selection, genetic drift, and recombination. Selection is modeled as single-locus terms (additive fitness) and two-loci terms (pairwise epistatic fitness). The problem is posed to infer epistatic fitness from population-wide whole-genome data from a time series of a developing population. We generate such data in silico and show that in the quasilinkage equilibrium phase of Kimura, Neher, and Shraiman, which pertains at high enough recombination rates and low enough mutation rates, epistatic fitness can be quantitatively correctly inferred using inverse Ising-Potts methods.
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Affiliation(s)
- Hong-Li Zeng
- School of Science, and New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, China.,Nordita, Royal Institute of Technology, and Stockholm University, SE-10691 Stockholm, Sweden
| | - Erik Aurell
- KTH-Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden.,Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-348 Kraków, Poland
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11
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Cantón R. [Current microbiological aspects of community respiratory infection beyond COVID-19]. REVISTA ESPANOLA DE QUIMIOTERAPIA : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE QUIMIOTERAPIA 2021; 34:81-92. [PMID: 33749214 PMCID: PMC8019468 DOI: 10.37201/req/049.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 03/21/2021] [Indexed: 12/22/2022]
Abstract
From a microbiological point of view, both empirical and targeted antimicrobial treatment in respiratory infection is based on the sensitivity profile of isolated microorganisms and the possible resistance mechanisms that they may present. The latter may vary in different geographic areas according to prescription profiles and vaccination programs. Beta-lactam antibiotics, fluoroquinolones, and macrolides are the most commonly used antimicrobials during the exacerbations of chronic obstructive pulmonary disease and community-acquired pneumonia. In their prescription, different aspects such as intrinsic activity, bactericidal effect or their ability to prevent the development of resistance must be taken into account. The latter is related to the PK/PD parameters, the mutant prevention concentration and the so-called selection window. More recently, the potential ecological impact has grown in importance, not only on the intestinal microbiota, but also on the respiratory one. Maintaining the state of eubiosis requires the use of antimicrobials with a low profile of action on anaerobic bacteria. With their use, the resilience of the bacterial populations belonging to the microbiota, the state of resistance of colonization and the collateral damage related to the emergence of resistance to the antimicrobials in pathogens causing the infections and in the bacterial populations integrating the microbiota.
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Affiliation(s)
- R Cantón
- Rafael Cantón. Servicio de Microbiología. Hospital Universitario Ramón y Cajal e Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS). Madrid. Spain.
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12
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Reslan L, Finianos M, Bitar I, Moumneh MB, Araj GF, Zaghlout A, Boutros C, Jisr T, Nabulsi M, Kara Yaccoub G, Hamze M, Osman M, Bou Raad E, Hrabak J, Matar GM, Dbaibo G. The Emergence of Invasive Streptococcus pneumoniae Serotype 24F in Lebanon: Complete Genome Sequencing Reveals High Virulence and Antimicrobial Resistance Characteristics. Front Microbiol 2021; 12:637813. [PMID: 33746930 PMCID: PMC7967862 DOI: 10.3389/fmicb.2021.637813] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/29/2021] [Indexed: 12/16/2022] Open
Abstract
Background Invasive pneumococcal disease (IPD) remains a global health problem. IPD incidence has significantly decreased by the use of pneumococcal conjugate vaccines (PCV). Nevertheless, non-PCV serotypes remain a matter of concern. Eight Streptococcus pneumoniae serotype 24F isolates, belonging to a non-PCV serotype, were detected through the Lebanese Inter-Hospital Pneumococcal Surveillance Program. The aim of the study is to characterize phenotypic and genomic features of the 24F isolates in Lebanon. Methods WGS using long reads sequencing (PacBio) was performed to produce complete circular genomes and to determine clonality, antimicrobial resistance and virulence determinants. Results The sequencing results yielded eight closed circular genomes. Three multilocus sequence typing (MLST) types were identified (ST11618, ST14184, ST15253). Both MLST and WGS analyses revealed that these isolates from Lebanon were genetically homogenous belonging to clonal complex CC230 and clustered closely with isolates originating from Canada, United States of America, United Kingdom and Iceland. Their penicillin binding protein profiles correlated with both β-lactam susceptibility patterns and MLST types. Moreover, the isolates harbored the macrolide and tetracycline resistance genes and showed a similar virulence gene profile. To our knowledge, this study represents the first report of complete phenotypic and genomic characterization of the emerging Streptococcus pneumoniae, serotype 24F, in the Middle East and North Africa region.
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Affiliation(s)
- Lina Reslan
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon
| | - Marc Finianos
- Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Plzen, Czechia
| | - Ibrahim Bitar
- Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Plzen, Czechia
| | - Mohamad Bahij Moumneh
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon
| | - George F Araj
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon.,Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Alissar Zaghlout
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon
| | - Celina Boutros
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon
| | - Tamima Jisr
- Department of Laboratory and Blood, Makassed General Hospital, Beirut, Lebanon
| | | | | | - Monzer Hamze
- Department of Microbiology, Nini Hospital, Tripoli, Lebanon
| | - Marwan Osman
- El-Youssef Hospital Center, Department of Clinical Laboratory, Halba, Lebanon
| | - Elie Bou Raad
- El-Youssef Hospital Center, Department of Clinical Laboratory, Halba, Lebanon
| | - Jaroslav Hrabak
- Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Plzen, Czechia
| | - Ghassan M Matar
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon.,Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Ghassan Dbaibo
- Center for Infectious Diseases Research (CIDR) and WHO Collaborating Center for Reference and Research on Bacterial Pathogens, American University of Beirut, Beirut, Lebanon.,Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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13
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Post-Vaccination Streptococcus pneumoniae Carriage and Virulence Gene Distribution among Children Less Than Five Years of Age, Cape Coast, Ghana. Microorganisms 2020; 8:microorganisms8121987. [PMID: 33322236 PMCID: PMC7764876 DOI: 10.3390/microorganisms8121987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 11/27/2020] [Accepted: 12/10/2020] [Indexed: 01/01/2023] Open
Abstract
In 2012, Ghana introduced PCV13 into its childhood immunization program. To monitor the pneumococcus after PCV13 vaccination, we analyzed serotypes, antibiotic resistance, and virulence genes of pneumococcal carriage isolates among children under five years of age. We obtained nasopharyngeal swabs from 513 children from kindergartens and immunization centers in Cape Coast, Ghana. Pneumococcal serotypes were determined by multiplex-PCR and Quellung reaction. Antibiotic resistance and virulence genes prevalence were determined by disc diffusion and PCR respectively. Overall, carriage prevalence was 29.4% and PCV13 coverage was 38.4%. Over 60% of the isolates were non-PCV13 serotypes and serotype 23B was the most prevalent. One isolate showed full resistance to penicillin, while 35% showed intermediate resistance. Resistance to erythromycin and clindamycin remained low, while susceptibility to ceftriaxone, levofloxacin and vancomycin remained high. Penicillin resistance was associated with PCV13 serotypes. Forty-three (28.5%) strains were multidrug-resistant. Virulence genes pavB, pcpA, psrP, pilus-1, and pilus-2 were detected in 100%, 87%, 62.9%, 11.9%, and 6.6% of the strains, respectively. The pilus islets were associated with PCV13 and multidrug-resistant serotypes. PCV13 vaccination had impacted on pneumococcal carriage with a significant increase in non-PCV13 serotypes and lower penicillin resistance. Including PcpA and PsrP in pneumococcal protein-based vaccines could be beneficial to Ghanaian children.
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14
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A Choline-Recognizing Monomeric Lysin, ClyJ-3m, Shows Elevated Activity against Streptococcus pneumoniae. Antimicrob Agents Chemother 2020; 64:AAC.00311-20. [PMID: 32958710 DOI: 10.1128/aac.00311-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 09/10/2020] [Indexed: 12/29/2022] Open
Abstract
Streptococcus pneumoniae is a leading pathogen for bacterial pneumonia, which can be treated with bacteriophage lysins harboring a conserved choline binding module (CBM). Such lysins regularly function as choline-recognizing dimers. Previously, we reported a pneumococcus-specific lysin ClyJ comprising the binding domain from the putative endolysin gp20 from the Streptococcus phage SPSL1 and the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) catalytic domain from the PlyC lysin. A variant of ClyJ with a shortened linker, i.e., ClyJ-3, shows improved activity and reduced cytotoxicity. Resembling typical CBM-containing lysins, ClyJ-3 dimerized upon binding with choline. Herein, we further report a choline-recognizing variant of ClyJ-3, i.e., ClyJ-3m, constructed by deleting its C-terminal tail. Biochemical characterization showed that ClyJ-3m remains a monomer after it binds to choline yet exhibits improved bactericidal activity against multiple pneumococcal strains with different serotypes. In an S. pneumoniae-infected bacteremia model, a single intraperitoneal administration of 2.32 μg/mouse of ClyJ-3m showed 70% protection, while only 20% of mice survived in the group receiving an equal dose of ClyJ-3 (P < 0.05). A pharmacokinetic analysis following single intravenously doses of 0.29 and 1.16 mg/kg of ClyJ-3 or ClyJ-3m in BALB/c mice revealed that ClyJ-3m shows a similar half-life but less clearance and a greater area under curve than ClyJ-3. Taken together, the choline-recognizing monomer ClyJ-3m exhibited enhanced bactericidal activity and improved pharmacokinetic proprieties compared to those of its parental ClyJ-3 lysin. Our study also provides a new way for rational design and programmed engineering of lysins targeting S. pneumoniae.
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15
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Lees JA, Mai TT, Galardini M, Wheeler NE, Horsfield ST, Parkhill J, Corander J. Improved Prediction of Bacterial Genotype-Phenotype Associations Using Interpretable Pangenome-Spanning Regressions. mBio 2020; 11:e01344-20. [PMID: 32636251 PMCID: PMC7343994 DOI: 10.1128/mbio.01344-20] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 06/05/2020] [Indexed: 12/19/2022] Open
Abstract
Discovery of genetic variants underlying bacterial phenotypes and the prediction of phenotypes such as antibiotic resistance are fundamental tasks in bacterial genomics. Genome-wide association study (GWAS) methods have been applied to study these relations, but the plastic nature of bacterial genomes and the clonal structure of bacterial populations creates challenges. We introduce an alignment-free method which finds sets of loci associated with bacterial phenotypes, quantifies the total effect of genetics on the phenotype, and allows accurate phenotype prediction, all within a single computationally scalable joint modeling framework. Genetic variants covering the entire pangenome are compactly represented by extended DNA sequence words known as unitigs, and model fitting is achieved using elastic net penalization, an extension of standard multiple regression. Using an extensive set of state-of-the-art bacterial population genomic data sets, we demonstrate that our approach performs accurate phenotype prediction, comparable to popular machine learning methods, while retaining both interpretability and computational efficiency. Compared to those of previous approaches, which test each genotype-phenotype association separately for each variant and apply a significance threshold, the variants selected by our joint modeling approach overlap substantially.IMPORTANCE Being able to identify the genetic variants responsible for specific bacterial phenotypes has been the goal of bacterial genetics since its inception and is fundamental to our current level of understanding of bacteria. This identification has been based primarily on painstaking experimentation, but the availability of large data sets of whole genomes with associated phenotype metadata promises to revolutionize this approach, not least for important clinical phenotypes that are not amenable to laboratory analysis. These models of phenotype-genotype association can in the future be used for rapid prediction of clinically important phenotypes such as antibiotic resistance and virulence by rapid-turnaround or point-of-care tests. However, despite much effort being put into adapting genome-wide association study (GWAS) approaches to cope with bacterium-specific problems, such as strong population structure and horizontal gene exchange, current approaches are not yet optimal. We describe a method that advances methodology for both association and generation of portable prediction models.
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Affiliation(s)
- John A Lees
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - T Tien Mai
- Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, University of Oslo, Oslo, Norway
| | - Marco Galardini
- Biological Design Center, Boston University, Boston, Massachusetts, USA
| | - Nicole E Wheeler
- Centre for Genomic Pathogen Surveillance, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Samuel T Horsfield
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Jukka Corander
- Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, University of Oslo, Oslo, Norway
- Centre for Genomic Pathogen Surveillance, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
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16
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Abstract
β-Lactam antibiotics are the first-line therapeutic option for Streptococcus pyogenes infections. Despite the global high prevalence of S. pyogenes infections and widespread use of β-lactams worldwide, reports of resistance to β-lactam antibiotics, such as penicillin, have been incredibly rare. Recently, β-lactam resistance, as defined by clinical breakpoints, was detected in two clinical S. pyogenes isolates with accompanying mutations in the active site of the penicillin binding protein PBP2x, raising concerns that β-lactam resistance will become more widespread. We screened a global database of S. pyogenes genome sequences to investigate the frequency of PBP mutations, identifying that PBP mutations are uncommon relative to those of Streptococcus pneumoniae. These findings support clinical observations that β-lactam resistance is rare in S. pyogenes and suggest that there are considerable constraints on S. pyogenes PBP sequence variation. A recent clinical report has linked Streptococcus pyogenes β-lactam antibiotic resistance to mutation in the penicillin binding protein (PBP) PBP2x. To determine whether this is an isolated case or reflects a broader prevalence of mutations that might confer reduced β-lactam susceptibility, we investigated the relative frequency of PBP sequence variation within a global database of 9,667 S. pyogenes isolates. We found that mutations in S. pyogenes PBPs (PBP2x, PBP1a, PBP1b, and PBP2a) occur infrequently across this global database, with fewer than 3 amino acid changes differing between >99% of the global population. Only 4 of the 9,667 strains contained mutations near transpeptidase active sites of PBP2x or PBP1a. The reported PBP2x T553K substitution was not identified. These findings are in contrast to those of 2,520 S. pneumococcus sequences where PBP mutations are relatively frequent and are often located in key β-lactam binding pockets. These data, combined with the general lack of penicillin resistance reported in S. pyogenes worldwide, suggests that extensive, unknown constraints restrict S. pyogenes PBP sequence plasticity. Our findings imply that while heavy antibiotic pressure may select for mutations in the PBPs, there is currently no evidence of such mutations becoming fixed in the S. pyogenes population or that mutations are being sequentially acquired in the PBPs. IMPORTANCE β-Lactam antibiotics are the first-line therapeutic option for Streptococcus pyogenes infections. Despite the global high prevalence of S. pyogenes infections and widespread use of β-lactams worldwide, reports of resistance to β-lactam antibiotics, such as penicillin, have been incredibly rare. Recently, β-lactam resistance, as defined by clinical breakpoints, was detected in two clinical S. pyogenes isolates with accompanying mutations in the active site of the penicillin binding protein PBP2x, raising concerns that β-lactam resistance will become more widespread. We screened a global database of S. pyogenes genome sequences to investigate the frequency of PBP mutations, identifying that PBP mutations are uncommon relative to those of Streptococcus pneumoniae. These findings support clinical observations that β-lactam resistance is rare in S. pyogenes and suggest that there are considerable constraints on S. pyogenes PBP sequence variation.
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