Isolation of thymidine-dependent and extended-spectrum-β-lactamase-producing Escherichia coli small-colony variant from urine of a septuagenarian female patient with recurrent cystitis: A case report with genetic investigation

Nagano, Natsumi; Kawakami, Yoshiyuki; Matsumoto, Takehisa; Tanimoto, Koichi; Kashihara, Masami; Nagata, Masahiro; Honjyo, Hideyasu; Yamamoto, Koji; Takada, Atsuaki; Sugiura, Tetsuro

doi:10.1016/j.jiac.2020.05.013

Cited by 5 publications

(4 citation statements)

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“…W literaturze można znaleźć opisy przypadków klinicznych, gdzie czynnikiem sprawczym były formy SCV innych niż gronkowiec złocisty czy pałeczka ropy błękitnej mikroorganizmów [9,31,35].…”

Section: Scv Innych Mikroorganizmówunclassified

“…Nagano i wsp. [31] opisali przypadek dziewczynki z nawracającym zapaleniem pęcherza moczowego. Czynnikiem sprawczym okazał się tymidynozależny fenotyp SCV E. coli.…”

Section: Scv Innych Mikroorganizmówunclassified

“…Jak zaznaczają autorzy dziewczynka podczas nawracających objawów zapalenia pęcherza leczona była trimetoprimem-sulfametoksazolem. W izolacie SCV wykryto delecję w genie thyA [31].…”

Section: Scv Innych Mikroorganizmówunclassified

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Small Colony Variants – The Cause Of Chronic Infections

Nowicka

Piątkowska

2021

Postępy Mikrobiologii - Advancements of Microbiology

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Some microorganisms are characterised by the ability to create specific morphological varieties called Small Colony Variants (SCVs). This characteristic was noted, among others, in Gram-positive cocci, mainly staphylococci, but also in Gram-negative bacilli. The properties of Small Colony Variants that differentiate them from wild-type colonies (mainly their small size) facilitate their intracellular survival (e.g. in epithelial or endothelial cells) as a result of which they can escape host immune response. In this way, SCV forms avoid the effects of complement components or antibodies. They are also characterised by resistance to antibiotics, mainly aminoglycoside or combination drugs, such as trimethoprim-sulfamethoxazole. The above features, which are important from a clinical point of view, namely small size and antibiotic resistance, make SCV one of the main causes of chronic, latent and recurrent infections which are difficult not only to diagnose, but also to treat. According to the literature, SCV of various microorganisms can be isolated from systemic infections of various organs and therefore from different clinical materials (e.g. blood, bones, soft tissues). SCV forms of Staphylococcus aureus are often isolated from patients with cystic fibrosis or osteomyelitis. The paper presents the characteristics and clinical relevance of this unique morphological form of bacteria. 1. General characteristics of SCV. 2. Formation mechanism of SCV. 3. Avoidance of host immunity by Small Colony Variants. 4. Clinical significance of SCV -description of selected cases. 4.1. Staphylococci. 4.2. Pseudomonas aeruginosa. 4.3. SCVs of other micro organisms.

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Section: Scv Innych Mikroorganizmówunclassified

“…Nagano i wsp. [31] opisali przypadek dziewczynki z nawracającym zapaleniem pęcherza moczowego. Czynnikiem sprawczym okazał się tymidynozależny fenotyp SCV E. coli.…”

Section: Scv Innych Mikroorganizmówunclassified

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Small Colony Variants – The Cause Of Chronic Infections

Nowicka

Piątkowska

2021

Postępy Mikrobiologii - Advancements of Microbiology

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“…The in vivo development of thymine auxotrophic SCVs of S. aureus has been widely described due to their role in persistent and recurrent infections [15,16], while this phenomenon is less reported for E. coli. A few recent studies have however investigated the phenotypic and genetic basis of thymine-dependent ESBL-producing clinical E. coli strains from patients with UTIs [17,18].…”

Section: Introductionmentioning

confidence: 99%

Phenotypic and genotypic characterisation of thymine auxotrophy in Escherichia coli isolated from a patient with recurrent bloodstream infection

et al. 2022

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Introduction Thymine auxotrophic in vitro mutants of Escherichia coli were first reported in the mid-20th century. Later, thymine-dependent clinical strains of E. coli as well as other Enterobacterales, Enterococcus faecalis and Staphylococcus aureus have been recognized as the cause of persistent and recurrent infections. Objectives The aim of this study was to characterize the phenotype and investigate the molecular basis of thymine auxotrophy in ten E. coli isolates obtained at different time points from a patient with recurrent bloodstream infection (BSI) due to a chronic aortic graft infection treated with Trimethoprim/sulfamethoxazole (TMP-SMX). Methods Clinical data was obtained from hospital records. Growth characterization and antimicrobial susceptibility testing to TMP-SMX was performed on M9 agar and in MH broth with different thymine concentrations (0.5, 2, 5, 10 and 20 μg/mL), on Mueller-Hinton (MH) and blood agar. Whole genome sequencing (WGS) was performed on all E. coli isolates. Results E. coli were isolated from ten consecutive BSI episodes from a patient with chronic aortic graft infection. Six of these isolates were resistant to TMP-SMX when assayed on blood agar. Growth experiments with added thymine confirmed that these isolates were thymine-dependent (thy-), and revealed growth defects (slower growth rate and smaller colony size) in these isolates relative to thy+ isolates (n = 4). WGS indicated that all isolates were of the same clonal lineage of sequence type 7358. Genomic analysis revealed a G172C substitution in thyA in all TMP-SMX resistant isolates, while mutations affecting genes involved in the deoxyribose salvage pathway (deoB and deoC) were identified in eight isolates. Conclusion This case highlights the risk of resistance development to TMP-SMX, especially for long-term treatment, and the possible pitfalls in detection of growth-deficient subpopulations from chronic infections, which could lead to treatment failure.

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Cotrimoxazole

2020

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Isolation of thymidine-dependent and extended-spectrum-β-lactamase-producing Escherichia coli small-colony variant from urine of a septuagenarian female patient with recurrent cystitis: A case report with genetic investigation

Cited by 5 publications

References 18 publications

Small Colony Variants – The Cause Of Chronic Infections

Small Colony Variants – The Cause Of Chronic Infections

Phenotypic and genotypic characterisation of thymine auxotrophy in Escherichia coli isolated from a patient with recurrent bloodstream infection

Cotrimoxazole

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