Evaluation of the stability of biochemical phenotypes of Escherichia coli upon subculturing and storage

Katouli, Mohammad; Kühn, Inger; Möllby, R.

doi:10.1099/00221287-136-9-1681

Cited by 24 publications

(20 citation statements)

References 20 publications

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“…Some of these BPTs had a high similarity to other BPTs in the same material. A previous study showed that some of the biotype characters of Escherichia coli change slightly upon subculturing and storage [29]. Changes have also been observed in some biochemical reactions of E. coli strains after oral inoculation of rats and subsequent recovery from faeces of the animals (unpublished observations).…”

Section: Discussionmentioning

confidence: 75%

“…Different strains are connected with vertical lines at the similarity level they show to each other and thus the higher the similarity value of this line, the more similar are the strains. An identity level (ID-level) of 0.975 was set based on reproducibility of the system [29]. Strains showing similarity coefficients higher than the ID-level were regarded as identical and assigned to the same biochemical phenotype (BPT).…”

Section: Characterisation Of Coliforrn Jeoramentioning

confidence: 99%

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Selective translocation of coliform bacteria adhering to caecal epithelium of rats during catabolic stress

Katouli

Nettebladt

Muratov

et al. 1997

Journal of Medical Microbiology

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Adult conventional rats were starved for 48 h with or without haemorrhage at 24 h, and translocation of caecal coliforms to mesenteric lymph nodes (MLNs) was measured. Translocation was detected in three of 11 rats without haemorrhage, in 6 of 11 starved and sham-operated rats and in 12 of 22 rats after haemorrhage. In contrast, only one of 13 non-instrumented and fed control rats showed translocation. Translocation was associated with more coliforms adhering to caecal epithelium in rats. Coliform isolates from caecum, caecal epithelium and MLNs were characterised and grouped into different biochemical phenotypes (BPTs) by a biochemical fingerprinting method. Of 291 BPTs detected in the caecum of all rats, 108 were also found on caecal epithelium; 36 BPTs were detected in MLNs, of which 17 were not detected either in the caecum or on the caecal epithelium of the corresponding rats. One isolate from each of these 36 BPTs was selected and compared to the others. Four common (C) BPTs (i.e., Cl-C4) were identified among them. Strains of C1 formed the majority of isolates from the caecum (79%), caecal epithelium (71%) and MLNs (91%). In contrast, C2-C4 had a significantly lower incidence both in the caecum and on the caecal epithelium, but not in the MLNs. These findings indicate that not all caecal coliforms adhere to the epithelium during catabolic stress and that for translocation to occur, other bacterial properties besides adhesion are needed. It is also concluded that coliforms with a low incidence in the caecum can translocate with the same efficiency as those with a high incidence.

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Section: Discussionmentioning

confidence: 75%

Section: Characterisation Of Coliforrn Jeoramentioning

confidence: 99%

Selective translocation of coliform bacteria adhering to caecal epithelium of rats during catabolic stress

Katouli

Nettebladt

Muratov

et al. 1997

Journal of Medical Microbiology

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“…Indeed, E. coli strains can have considerable biochemical variability (9), and biotyping can be a dependable method for their characterization (3,12,17).…”

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High Metabolic Potential May Contribute to the Success of ST131 Uropathogenic Escherichia coli

et al. 2012

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Uropathogenic Escherichia coli (UPEC) is the predominant cause of urinary tract infection in both hospital and community settings. The recent emergence of multidrug-resistant clones like the O25b:H4-ST131 lineage represents a significant threat to health, and numerous studies have explored the virulence potential of these organisms. Members of the ST131 clone have been described as having variable carriage of key virulence factors, and it has been suggested that additional unidentified factors contribute to virulence. Here we demonstrated that ST131 isolates have high metabolic potential and biochemical profiles that distinguish them from isolates of many other sequence types (STs). A collection of 300 UPEC isolates recovered in 2007 and 2009 in the Northwest region of England were subjected to metabolic profiling using the Vitek2 Advanced Expert System (AES). Of the 47 tests carried out, 30 gave a positive result with at least one of the 300 isolates examined. ST131 isolates demonstrated significant association with eight tests, including those for peptidase, decarboxylase, and alkalinization activity. Metabolic activity also correlated with antibiotic susceptibility profiles, with resistant organisms displaying the highest metabolic potential. This is the first comprehensive study of metabolic potential in the ST131 lineage, and we suggest that high metabolic potential may have contributed to the fitness of members of the ST131 clone, which are able to exploit the available nutrients in both the intestinal and urinary tract environments.

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“…If a subcultured strain gave values outside the mean inter-assay variation f 2 SD for a test, when compared to the original culture of that strain, it was regarded as a change in that particular test . 28 Second, the similarities obtained from comparisons of pairs of 20 strains before and after subculturing were calculated.…”

Section: Discriminatory Powermentioning

confidence: 99%

Evaluation of the PhP System for biochemical-fingerprint typing of strains of Salmonella of serotype Typhimurium

Katouli

Kühn

Wollin

et al. 1992

Journal of Medical Microbiology

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Summary. The Phene Plate (PhP) system of biochemical fingerprinting of bacteria is a computerised typing system, based on quantitative measurements of the kinetics of several biochemical reactions of bacteria grown in liquid medium in microtitration plates. For each isolate tested, it yields a biochemical fingerprint comprising several kinds of quantitative data which are useful for establishing similarities among strains with a personal-computer program. In this study, a set of 16 specific substrates was chosen to differentiate strains of Salmonella of serotype Typhimurium. The system was evaluated for its typability, reproducibility and discriminatory power in tests with a collection of 100 epidemiologically unrelated Typhimurium strains and results were compared with those obtained by phage typing. At an identity level of 0.980, strains were assigned by this method to 51 biochemical phenotypes (BPTs), giving a diversity index of 0.963 and a resolution index of 0.210. In contrast, 24 phage types (PTs) were identified among these isolates (a diversity index of 0.901). The combined use of biochemical fingerprinting by the PhP system and phage typing discriminated 82 phenotypes (a diversity index of 0.994). Stability of markers in each of the methods was also evaluated after subculture of 20 strains for 21 consecutive days. Only nine biochemical reactions were found that were subject to small, but measurable, changes for at least one isolate. These changes slightly decreased the mean similarity coefficients among strains but the overall BPTs of the strains showed changes in four strains (20 %). In contrast, eight strains (40 %) showed changes in their PTs after this treatment. It is concluded that the PhP system is a highly discriminatory and reproducible method for typing Typhimurium strains. It is easy to perform, and may be used alone or in combination with phage typing in epidemiological studies of Typhimurium strains.

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Evaluation of the stability of biochemical phenotypes of Escherichia coli upon subculturing and storage

Abstract: Stability of the biotypic characters of 72 enteropathogenic Escherichia culi (EPEC) and 21 faecal E. cufi strains was evaluated after storage and after subculturing using a computerized biochemical fingerprinting method.

Cited by 24 publications

References 20 publications

Selective translocation of coliform bacteria adhering to caecal epithelium of rats during catabolic stress

Selective translocation of coliform bacteria adhering to caecal epithelium of rats during catabolic stress

High Metabolic Potential May Contribute to the Success of ST131 Uropathogenic Escherichia coli

Evaluation of the PhP System for biochemical-fingerprint typing of strains of Salmonella of serotype Typhimurium

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