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Kalalah AA, Koenig SSK, Feng P, Bosilevac JM, Bono JL, Eppinger M. Pathogenomes of Shiga Toxin Positive and Negative Escherichia coli O157:H7 Strains TT12A and TT12B: Comprehensive Phylogenomic Analysis Using Closed Genomes. Microorganisms 2024; 12:699. [PMID: 38674643 PMCID: PMC11052207 DOI: 10.3390/microorganisms12040699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
Shiga toxin-producing Escherichia coli are zoonotic pathogens that cause food-borne human disease. Among these, the O157:H7 serotype has evolved from an enteropathogenic O55:H7 ancestor through the displacement of the somatic gene cluster and recurrent toxigenic conversion by Shiga toxin-converting bacteriophages. However, atypical strains that lack the Shiga toxin, the characteristic virulence hallmark, are circulating in this lineage. For this study, we analyzed the pathogenome and virulence inventories of the stx+ strain, TT12A, isolated from a patient with hemorrhagic colitis, and its respective co-isolated stx- strain, TT12B. Sequencing the genomes to closure proved critical to the cataloguing of subtle strain differentiating sequence and structural polymorphisms at a high-level of phylogenetic accuracy and resolution. Phylogenomic profiling revealed SNP and MLST profiles similar to the near clonal outbreak isolates. Their prophage inventories, however, were notably different. The attenuated atypical non-shigatoxigenic status of TT12B is explained by the absence of both the ΦStx1a- and ΦStx2a-prophages carried by TT12A, and we also recorded further alterations in the non-Stx prophage complement. Phenotypic characterization indicated that culture growth was directly impacted by the strains' distinct lytic phage complement. Altogether, our phylogenomic and phenotypic analyses show that these intimately related isogenic strains are on divergent Stx(+/stx-) evolutionary paths.
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Affiliation(s)
- Anwar A. Kalalah
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX 78249, USA
| | - Sara S. K. Koenig
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX 78249, USA
| | - Peter Feng
- U.S. Food and Drug Administration (FDA), College Park, MD 20740, USA
| | - Joseph M. Bosilevac
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | - James L. Bono
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | - Mark Eppinger
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX 78249, USA
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Kalalah AA, Koenig SSK, Bono JL, Bosilevac JM, Eppinger M. Pathogenomes and virulence profiles of representative big six non-O157 serogroup Shiga toxin-producing Escherichia coli. Front Microbiol 2024; 15:1364026. [PMID: 38562479 PMCID: PMC10982417 DOI: 10.3389/fmicb.2024.1364026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 02/29/2024] [Indexed: 04/04/2024] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) of non-O157:H7 serotypes are responsible for global and widespread human food-borne disease. Among these serogroups, O26, O45, O103, O111, O121, and O145 account for the majority of clinical infections and are colloquially referred to as the "Big Six." The "Big Six" strain panel we sequenced and analyzed in this study are reference type cultures comprised of six strains representing each of the non-O157 STEC serogroups curated and distributed by the American Type Culture Collection (ATCC) as a resource to the research community under panel number ATCC MP-9. The application of long- and short-read hybrid sequencing yielded closed chromosomes and a total of 14 plasmids of diverse functions. Through high-resolution comparative phylogenomics, we cataloged the shared and strain-specific virulence and resistance gene content and established the close relationship of serogroup O26 and O103 strains featuring flagellar H-type 11. Virulence phenotyping revealed statistically significant differences in the Stx-production capabilities that we found to be correlated to the strain's individual stx-status. Among the carried Stx1a, Stx2a, and Stx2d phages, the Stx2a phage is by far the most responsive upon RecA-mediated phage mobilization, and in consequence, stx2a + isolates produced the highest-level of toxin in this panel. The availability of high-quality closed genomes for this "Big Six" reference set, including carried plasmids, along with the recorded genomic virulence profiles and Stx-production phenotypes will provide a valuable foundation to further explore the plasticity in evolutionary trajectories in these emerging non-O157 STEC lineages, which are major culprits of human food-borne disease.
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Affiliation(s)
- Anwar A. Kalalah
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - Sara S. K. Koenig
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - James L. Bono
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Meat Animal Research Center, Clay Center, NE, United States
| | - Joseph M. Bosilevac
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Meat Animal Research Center, Clay Center, NE, United States
| | - Mark Eppinger
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
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Nicholson TL, Kalalah AA, Eppinger M. Population structure and genetic diversity of Streptococcus suis isolates obtained from the United States. Front Microbiol 2023; 14:1250265. [PMID: 37808309 PMCID: PMC10551183 DOI: 10.3389/fmicb.2023.1250265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/22/2023] [Indexed: 10/10/2023] Open
Abstract
Diseases caused by the zoonotic pathogen Streptococcus suis are an extensive economic problem as well as an animal welfare concern for the global swine industry. Previous studies have evaluated the genomic diversity and population structure of S. suis isolates, however, the majority of these studies utilized isolates obtained from countries other than the U.S. This study applied whole genome sequencing and cgMLST-based typing to evaluate the population structure and genetic relatedness among S. suis isolates obtained within the U.S. The established high-resolution phylogenomic framework revealed extensive genomic variation and diversity among the sampled S. suis isolates, with isolates from the U.S. and from countries outside the U.S. found interspersed in the phylogeny. S. suis isolates obtained within the U.S. did not cluster by state or geographic location, however, isolates with similar serotypes, both obtained from within and outside the U.S., generally clustered together. Average nucleotide identity (ANI) values determined for the S. suis genomes were extensively broad, approaching the recommended species demarcation value, and correlated with the phylogenetic group distribution of the cgMLST-based tree. Numerous antimicrobial resistance (AMR) elements were identified among both U.S. and non-U.S. isolates with ble, tetO, and ermB genes identified as the most prevalent. The epf, mrp, and sly genes, historically used as markers for virulence potential, were also observed in the genomes of isolates that grouped together forming a subclade of clonal complex 1 (CC1) isolates. Collectively, the data in this report provides critical information needed to address potential biosurveillance needs and insights into the genetic diversity and population structure of S. suis isolates obtained within the U.S.
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Affiliation(s)
- Tracy L. Nicholson
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Anwar A. Kalalah
- South Texas Center for Emerging Infectious Diseases (STCEID), The University of Texas at San Antonio, San Antonio, TX, United States
- Department of Molecular Microbiology and Immunology (MMI), The University of Texas at San Antonio, San Antonio, TX, United States
| | - Mark Eppinger
- South Texas Center for Emerging Infectious Diseases (STCEID), The University of Texas at San Antonio, San Antonio, TX, United States
- Department of Molecular Microbiology and Immunology (MMI), The University of Texas at San Antonio, San Antonio, TX, United States
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Eppinger M, Almería S, Allué-Guardia A, Bagi LK, Kalalah AA, Gurtler JB, Fratamico PM. Genome Sequence Analysis and Characterization of Shiga Toxin 2 Production by Escherichia coli O157:H7 Strains Associated With a Laboratory Infection. Front Cell Infect Microbiol 2022; 12:888568. [PMID: 35770066 PMCID: PMC9234449 DOI: 10.3389/fcimb.2022.888568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/03/2022] [Indexed: 11/21/2022] Open
Abstract
A laboratory-acquired E. coli O157:H7 infection with associated severe sequelae including hemolytic uremic syndrome occurred in an individual working in the laboratory with a mixture of nalidixic acid-resistant (NalR) O157:H7 mutant strains in a soil-biochar blend. The patient was hospitalized and treated with an intravenous combination of metronidazole and levofloxacin. The present study investigated the source of this severe laboratory acquired infection and further examined the influence of the antibiotics used during treatment on the expression and production of Shiga toxin. Genomes of two Stx2a-and eae-positive O157:H7 strains isolated from the patient's stool were sequenced along with two pairs of the wt strains and their derived NalR mutants used in the laboratory experiments. High-resolution SNP typing determined the strains' individual genetic relatedness and unambiguously identified the two laboratory-derived NalR mutant strains as the source of the researcher's life-threatening disease, rather than a conceivable ingestion of unrelated O157:H7 isolates circulating at the same time. It was further confirmed that in sublethal doses, the antibiotics increased toxin expression and production. Our results support a simultaneous co-infection with clinical strains in the laboratory, which were the causative agents of previous O157:H7 outbreaks, and further that the administration of antibiotics may have impacted the outcome of the infection.
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Affiliation(s)
- Mark Eppinger
- Department of Molecular Microbiology and Immunology (MMI), University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - Sonia Almería
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
| | - Anna Allué-Guardia
- Department of Molecular Microbiology and Immunology (MMI), University of Texas at San Antonio, San Antonio, TX, United States
| | - Lori K Bagi
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
| | - Anwar A Kalalah
- Department of Molecular Microbiology and Immunology (MMI), University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - Joshua B Gurtler
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
| | - Pina M Fratamico
- United States (US) Department of Agriculture (USDA), Agricultural Research Service (ARS), Eastern Regional Research Center, Wyndmoor, PA, United States
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