Unveiling the Virulent Genotype and Unusual Biochemical Behavior of Escherichia coli ST59

Author(s):Show less -

de Mello Santos, Ana Carolina ^[1] ; Fuga, Bruna ^[2] ; Esposito, Fernanda ^[3] ; Cardoso, Brenda ^[2] ; Santos, Fernanda Fernandes ^[4] ; Valiatti, Tiago Barcelos ^[4] ; Santos-Neto, Jose Francisco ^[1] ; Gales, Ana Cristina ^[4] ; Lincopan, Nilton ^{[2, 3]} ; Silva, Rosa Maria ^[1] ; Tardelli Gomes, Tania Aparecida ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Microbiol Imunol & Parasitol, Escola Paulista Med, Disciplina Microbiol, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Ciencias Biomed, Dept Microbiol, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Fac Ciencias Farmaceut, Dept Anal Clin, Sao Paulo - Brazil

^[4] Univ Fed Sao Paulo, Dept Med, Lab ALERTA, Escola Paulista Med, Disciplina Infectol, Sao Paulo - Brazil

• Document type: Journal article
• Source: Applied and Environmental Microbiology; v. 87, n. 16 AUG 2021.
• Web of Science Citations: 0

Abstract

Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of human and animal infections worldwide. The utilization of selective and differential media to facilitate the isolation and identification of E coli from complex samples, such as water, food, sediment, and gut tissue, is common in epidemiological studies. During a surveillance study, we identified an E. coli strain isolated from human blood culture that displayed atypical light cream-colored colonies in chromogenic agar and was unable to produce beta-glucuronidase and beta-galactosidase in biochemical tests. Genomic analysis showed that the strain belongs to sequence type 59 (ST59) and phylogroup F. The evaluation in silico of 104 available sequenced lineages of ST59 complex showed that most of them belong to serotype O1:K1:H7, are beta-glucuronidase negative, and harbor a virulent genotype associated with the presence of important virulence markers such as pap, kpsE, chuA, fruA, and yfcV. Most of them were isolated from extraintestinal human infections in diverse countries worldwide and could be clustered/subgrouped based on papAF allele analysis. Considering that all analyzed strains harbor a virulent genotype and most do not exhibit biochemical behavior typical of E. coli, we report that they could be misclassified or underestimated, especially in epidemiological studies where the screening criteria rely only on typical biochemical phenotypes, as happens when chromogenic media are used. IMPORTANCE The use of selective and differential media guides presumptive bacterial identification based on specific metabolic traits that are specific to each bacterial species. When a bacterial specimen displays an unusual phenotype in these media, this characteristic may lead to bacterial misidentification or a significant delay in its identification, putting a patient at risk depending on the infection type. In the present work, we describe a virulent E. coli sequence type (ST59) that does not produce beta-glucuronidase (GUS negative), production of which is the metabolic trait widely used for E. coli presumptive identification in diverse differential media. The recognition of this unusual metabolic trait may help in the proper identification of ST59 isolates, the identification of their reservoir, and the evaluation of the frequency of these pathogens in places where automatic identification methods are not available. (AU)

• FAPESP's process: 19/15578-4 - Virulome and pathogenicity of carbapenem- and polymyxin-resistant priority pathogens
• Grantee: Fernanda Ribeiro dos Santos Esposito
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/00402-6 - Temporal study of the variability of virulence factors and phylogenetic groups of extraintestinal pathogenic Escherichia coli (ExPEC) isolated from bacteremia in patients of one Hospital in Sao Paulo: its relationship with ExPEC evolution
• Grantee: Rosa Maria Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/17353-7 - COMPARATIVE ANALYSIS OF VIRULENCE CHARACTERISTICS OF DIARRHEIOGENIC Escherichia coli IN E. coli STRAINS ISOLATED FROM PATIENTS WITH DIFFERENT TYPES OF URINARY INFECTION
• Grantee: Tânia Aparecida Tardelli Gomes do Amaral
• Support Opportunities: Regular Research Grants