Spontaneous recombination between homologous prophage regions causes large-scale inversions within the Escherichia coli O157:H7 chromosome

Temperature abuse during commercial transport and retail sale of leafy greens negatively impacts both microbial safety and product quality. Consequently, the effect of fluctuating temperatures on Escherichia coli O157:H7 and Listeria monocytogenes growth in commercially-bagged salad greens was assessed during transport, retail storage, and display. Over a 16-month period, a series of time-temperature profiles for bagged salads were obtained from five transportation routes covering four geographic regions (432 profiles), as well as during retail storage (4,867 profiles) and display (3,799 profiles). Five different time-temperature profiles collected during 2 to 3 days of transport, 1 and 3 days of retail storage, and 3 days of retail display were then duplicated in a programmable incubator to assess E. coli O157:H7 and L. monocytogenes growth in commercial bags of romaine lettuce mix. Microbial growth predictions using the Koseki-Isobe and McKellar-Delaquis models were validated by comparing the root mean square error (RMSE), bias, and the acceptable prediction zone between the laboratory growth data and model predictions. Monte Carlo simulations were performed to calculate the probability distribution of microbial growth from 8,122,127,472 scenarios during transport, cold room storage, and retail display. Using inoculated bags of retail salad, E. coli O157:H7 and L. monocytogenes populations increased a maximum of 3.1 and 3.0 log CFU/g at retail storage. Both models yielded acceptable RMSEs and biases within the acceptable prediction zone for E. coli O157:H7. Based on the simulation, both pathogens generally increased <2 log CFU/g during transport, storage, and display. However, retail storage duration can significantly impact pathogen growth. This large-scale U.S. study—the first using commercial time/temperature profiles to assess the microbial risk of leafy greens—should be useful in filling some of the data gaps in current risk assessments for leafy greens.

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Isolation and Antimicrobial Susceptibility Profile of Escherichia coli O157 : H7 from Raw Milk of Dairy Cattle in Holeta District, Central Ethiopia

International Journal of Microbiology ◽

10.1155/2020/6626488 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Ashenafi Ababu ◽

Dereje Endashaw ◽

Haben Fesseha

Keyword(s):

Escherichia Coli ◽

Dairy Cattle ◽

Antimicrobial Susceptibility ◽

Large Scale ◽

Raw Milk ◽

Herd Size ◽

Escherichia Coli O157 ◽

Cross Sectional ◽

E Coli ◽

Antimicrobial Susceptibility Profile

A cross-sectional study was conducted in small, medium, and large-scale dairy farms of Holeta district to isolate, identify, and antimicrobial susceptibility profile of Escherichia coli O157 : H7 in raw milk of dairy cattle. A total of 210 lactating cows were selected for raw milk samples, and 19% (40/210) were found to be positive for E. coli whereas 5.2% (11/210) were confirmed as E. coli O157 : H7 positive using the Escherichia coli O157 latex test. Accordingly, all E. coli was highly susceptible to Ciprofloxacin (100%), Gentamycin (100%), Oxytetracycline (100%), and Tetracycline (63.63%). Furthermore, the resistance of 72.73%, 54.54%, 54.54%, and 45.45% was developed to Cefoxitin, Sulphamethoxazole, Cloxacillin, and Streptomycin, respectively. Factors such as parity, age, body condition, herd size, milk yield, udder hygiene, and udder lesion showed a statistically significant ( p < 0.05 ) association with the occurrence of E. coli infection in dairy cattle. In conclusion, in this study, a higher prevalence of Escherichia coli O157 : H7 and its drug susceptibility profile is an alarm for the health of the public, and awareness creation to the farm owners and the community is recommended.

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Detection of Escherichia coli O157:H7 and Salmonella Typhimurium Using Filtration followed by Fourier-Transform Infrared Spectroscopy†

Journal of Food Protection ◽

10.4315/0362-028x-69.8.1777 ◽

2006 ◽

Vol 69 (8) ◽

pp. 1777-1784 ◽

Cited By ~ 21

Author(s):

Y. BURGULA ◽

D. KHALI ◽

S. KIM ◽

S. S. KRISHNAN ◽

M. A. COUSIN ◽

...

Keyword(s):

Escherichia Coli ◽

Fourier Transform ◽

Infrared Spectroscopy ◽

Salmonella Typhimurium ◽

Fourier Transform Infrared Spectroscopy ◽

Large Scale ◽

Fourier Transform Infrared ◽

Nondestructive Method ◽

Escherichia Coli O157 ◽

Infrared Microscope

Fourier-transform infrared spectroscopy has been successfully used as a nondestructive method for identifying, distinguishing, and classifying pathogens. In this study, a less time-consuming Fourier-transform infrared procedure was developed to identify Escherichia coli O157:H7 and Salmonella Typhimurium. Samples containing 109 CFU/ml were prepared in tryptic soy broth and then serially diluted (up to eight times) to obtain bacterial solutions of 109 to 10 CFU/ml. These dilutions were incubated at 37°C for 6 h, samples were filtered through a Metricel filter hourly (for 0 to 6 h), and spectra were obtained using a ZnSe contact attenuated total reflectance accessory on a Continuμm infrared microscope. Midinfrared spectra (4,000 to 700 cm−1)of Salmonella Typhimurium and E. coli O157:H7 were generated, and peak areas in the region of 1,589 to 1,493 cm−1 were used to detect the pathogens. Initially, detection limits were between 106 and 107 CFU/ml without preenrichment, and samples starting with 500 CFU/ml were detectable following incubation for 6 h, when counts reached at least 106 CFU/ml. Compared with results of previously published studies in which Fourier-transform infrared spectroscopy was used to identify select pathogens, this method is more rapid and less expensive for practical large-scale sample analysis.

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The effect of Verotoxin Producing Escherichia coli in Development of Experimental Gastroenteritis among Streptomycin Treated Murine Model: A Longitudinal Study

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v30i1-2.28450 ◽

2016 ◽

Vol 30 (1-2) ◽

pp. 31-38

Author(s):

Fahareen Binta Mosharraf ◽

Chowdhury Rafiqul Ahsan ◽

Jamalun Nessa ◽

Mahmuda Yasmin

Keyword(s):

Escherichia Coli ◽

Large Scale ◽

Lethal Dose ◽

Escherichia Coli O157 ◽

Disease Symptoms ◽

E Coli ◽

Sporadic Cases ◽

Alternative Routes ◽

Minimum Lethal Dose

Escherichia coli O157:H7 is a newly emerged pathogen, which has been recognized as a major cause of large scale epidemics and thousands of sporadic cases of gastrointestinal illness. This observation particularly calls for the in vivo examination of E. coli O157 candidates in an attempt to mimic various aspects of E. coli O157:H7 disease symptoms in humans. Healthy conventional Swiss albino mice were used for investigating the clinical manifestation exerted by stx1A and stx2A positive E. coli O157:H7 in various doses applied through three alternative routes (oral, intramuscular and intraperitoneal). The highest titer of orally added E. coli 0157:H7 (109 CFU ml-1) among the five test doses had started symptoms at the earliest time and manifested most of the classical symptoms. The symptoms started to become visible at 14th hour, increased with time and had reached moribund condition near 48th hour just before death of the host. The oral way of E. coli O157:H7 addition at the dose of 100 ?l suspension containing 1 X 109CFU ml-1 was taken as the most potent concentration in producing bacterial fatality and hence was selected as the Minimum Lethal Dose (MLD).Bangladesh J Microbiol, Volume 30, Number 1-2,June-Dec 2013, pp 31-38

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Bedeutung von Escherichia coli O157 beim Schlachtschaf in der Schweiz

Schweizer Archiv für Tierheilkunde ◽

10.1024/0036-7281.148.6.289 ◽

2006 ◽

Vol 148 (6) ◽

pp. 289-295 ◽

Cited By ~ 8

Author(s):

C. Zweifel ◽

M. Kaufmann ◽

J. Blanco ◽

R. Stephan

Keyword(s):

Escherichia Coli ◽

Escherichia Coli O157

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Molecular profiling and antimicrobial susceptibility of Escherichia coli O157:H7 isolated in Bulgaria

BULGARIAN JOURNAL OF VETERINARY MEDICINE ◽

10.15547/bjvm.2263 ◽

2020 ◽

Vol 23 (3) ◽

pp. 310-318

Author(s):

K. Koev ◽

T. Stoyanchev ◽

G. Zhelev ◽

P. Marutsov ◽

K. Gospodinova ◽

...

Keyword(s):

Escherichia Coli ◽

Escherichia Coli O157 ◽

Acid Sensitivity ◽

Lower Extent ◽

Phenotype Analysis ◽

Anal Swab ◽

Amoxicillin Clavulanic Acid ◽

Primary Identification ◽

Stx1 Gene ◽

Cattle Farms

The purpose of this study was to detect the presence of shiga-toxin producing Escherichia coli (STEC) in faeces of healthy dairy cattle and to determine the sensitivity of isolates to several antimicrobial drugs. A total of 1,104 anal swab samples originating from 28 cattle farms were examined. After the primary identification, 30 strains were found to belong to serogroup О157. By means of conventional multiplex PCR, isolates were screened for presence of resistance genes stx1, stx2 and eaeА. Twenty-nine strains possesses amplicons with a size corresponding to genes stx2 and eaeA, one had amplicons also for the stx1 gene and one lacked amplicons of all three genes. Twenty-eight strains demonstrated amplicons equivalent to gene H7. The results from phenotype analysis of resistance showed preserved sensitivity to ceftriaxone, ceftazidime, cefotaxime, cephalothin, streptomycin, gentamicin, tetracycline, enrofloxacin and combinations sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Sensitivity to ampicillin was relatively preserved, although at a lower extent.

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