scholarly journals A Statistical Model for Assessing Sample Size for Bacterial Colony Selection: A Case Study of Escherichia Coli and Avian Cellulitis

2000 ◽  
Vol 12 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Randall S. Singer ◽  
Wesley O. Johnson ◽  
Joan S. Jeffrey ◽  
Richard P. Chin ◽  
Tim E. Carpenter ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Statistical Model ◽  
Clinical Sample ◽  
Agar Plate ◽  
Sample Sizes ◽  
Simple Task ◽  
Single Strain ◽  
Bacterial Colony ◽  
E Coli

A general problem for microbiologists is determining the number of phenotypically similar colonies growing on an agar plate that must be analyzed in order to be confident of identifying all of the different strains present in the sample. If a specified number of colonies is picked from a plate on which the number of unique strains of bacteria is unknown, assigning a probability of correctly identifying all of the strains present on the plate is not a simple task. With Escherichia coli of avian cellulitis origin as a case study, a statistical model was designed that would delineate sample sizes for efficient and consistent identification of all the strains of phenotypically similar bacteria in a clinical sample. This model enables the microbiologist to calculate the probability that all of the strains contained within the sample are correctly identified and to generate probability-based sample sizes for colony identification. The probability of cellulitis lesions containing a single strain of E. coli was 95.4%. If one E. coli strain is observed out of three colonies randomly selected from a future agar plate, the probability is 98.8% that only one strain is on the plate. These results are specific for this cellulitis E. coli scenario. For systems in which the number of bacterial strains per sample is variable, this model provides a quantitative means by which sample sizes can be determined.

scholarly journals Quantifying within- and between-animal variation and uncertainty associated with counts of Escherichia coli O157 occurring in naturally infected cattle faeces

2008 ◽  
Vol 6 (31) ◽  
pp. 169-177 ◽  
Author(s):  
S.E Robinson ◽  
P.E Brown ◽  
E.J Wright ◽  
C.A Hart ◽  
N.P French
Keyword(s):  
Escherichia Coli ◽  
Statistical Model ◽  
Human Infection ◽  
Microbial Count ◽  
Infected Cattle ◽  
Explanatory Variables ◽  
E Coli ◽  
Fixed And Random Effects ◽  
Cattle Faeces ◽  
Multiple Samples

Cattle faeces are considered the most important reservoir for human infection with Escherichia coli O157. We have previously described shedding of E. coli O157 in the faeces of naturally infected cattle cohorts. However, the data require further investigation to quantify the uncertainty and variability in the estimates previously presented. This paper proposes a method for analysing both the presence and the quantity of E. coli O157 in cattle faecal samples, using two isolation procedures, one of which enumerates E. coli O157. The combination of these two measurements, which are fundamentally different in nature and yet measuring a common outcome, has necessitated the development of a novel statistical model for ascertaining the contribution of the various components of variation (both natural and observation induced) and for judging the influence of explanatory variables. Most of the variation within the sampling hierarchy was attributable to multiple samples from the same animal. The contribution of laboratory-level variation was found to be low. After adjusting for fixed and random effects, short periods of increased intensity of shedding were identified in individual animals. We conclude that within-animal variation is greater than between animals over time, and studies aiming to elucidate the dynamics of shedding should focus resources, sampling more within than between animals. These findings have implications for the identification of persistent high shedders and for assessing their role in the epidemiology of E. coli O157 in cattle populations. The development of this non-standard statistical model may have many applications to other microbial count data.

scholarly journals Spread of Antibiotic Resistance in Aquatic Environments: E. coli as a Case Study

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 693 ◽  
Author(s):  
Maria Adamantia Efstratiou ◽  
Marina Bountouni ◽  
Efthimios Kefalas
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Antibiotic Resistance ◽  
Rural Communities ◽  
Ground Water ◽  
Aquatic Environments ◽  
Multiple Resistance ◽  
E Coli ◽  
Of Greece

The aim of this study was to gather information on the spread of antibiotic resistance in Escherichia coli isolates from wells, boreholes and untreated drinking water in islands of Greece. We analyzed for antibiotic resistance 235 E. coli strains isolated from untreated drinking water of small rural communities, and ground water from 4 islands. Resistance was tested against Norfloxacin, Ciprofloxacin, Levofloxacin, Amoxicillin and Cefaclor. More than half (54.9%) were resistant to at least one of the antibiotics tested. Of these 26.3% showed multiple resistance (to two or more antibiotics). Strains from drinking water sources were overall more sensitive. Frequent resistance was observed for Amoxicillin (38.3%) and Levofloxacin (28.5%), low for Norfloxacin (5.5%).

scholarly journals Detection of biofilm among uropathogenic Escherichia coli and its correlation with antibiotic resistance pattern

2019 ◽  
Vol 11 (01) ◽  
pp. 017-022 ◽  
Author(s):  
Rashmi M. Karigoudar ◽  
Mahesh H. Karigoudar ◽  
Sanjay M. Wavare ◽  
Smita S. Mangalgi
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Agar Plate ◽  
Diffusion Method ◽  
Resistance Pattern ◽  
Susceptibility Pattern ◽  
Sensitivity Testing ◽  
E Coli ◽  
Tract Infections

Abstract BACKGROUND: Escherichia coli accounts for 70%–95% of urinary tract infections (UTIs). UTI is a serious health problem with respect to antibiotic resistance and biofilms formation being the prime cause for the antibiotic resistance. Biofilm can restrict the diffusion of substances and binding of antimicrobials. In this context, the present study is aimed to perform in vitro detection of biofilm formation among E. coli strains isolated from urine and to correlate their susceptibility pattern with biofilm formation. MATERIALS AND METHODS: A total of 100 E. coli strains isolated from patients suffering from UTI were included in the study. The identification of E. coli was performed by colony morphology, Gram staining, and standard biochemical tests. The detection of biofilm was carried out by Congo Red Agar (CRA) method, tube method (TM), and tissue culture plate (TCP) method. Antimicrobial sensitivity testing was performed by Kirby–Bauer disc diffusion method on Muller–Hinton agar plate. RESULTS: Of the 100 E. coli strains, 49 (49%) and 51 (51%) were from catheterized and noncatheterized patients, respectively. Biofilm production was positive by CRA, TM, and TCP method were 49 (49%), 55 (55%), and 69 (69%), respectively. Biofilm producers showed maximum resistance to co-trimoxazole (73.9%), gentamicin (94.2%), and imipenem (11.6%) when compared to nonbiofilm producers. Significant association was seen between resistance to antibiotic and biofilm formation with a P = 0.01 (<0.05). CONCLUSION: A greater understanding of biofilm detection in E. coli will help in the development of newer and more effective treatment. The detection of biofilm formation and antibiotic susceptibility pattern helps in choosing the correct antibiotic therapy.

Predicting Survival of Escherichia coli O157:H7 in Dry Fermented Sausage Using Artificial Neural Networks

2008 ◽  
Vol 71 (1) ◽  
pp. 6-12 ◽  
Author(s):  
A. PALANICHAMY ◽  
D. S. JAYAS ◽  
R. A. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Neural Networks ◽  
Artificial Neural Networks ◽  
Statistical Model ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
Fermented Sausage ◽  
E Coli ◽  
Dry Fermented Sausage ◽  
Artificial Neural

The Canadian Food Inspection Agency required the meat industry to ensure Escherichia coli O157:H7 does not survive (experiences ≥ 5 log CFU/g reduction) in dry fermented sausage (salami) during processing after a series of foodborne illness outbreaks resulting from this pathogenic bacterium occurred. The industry is in need of an effective technique like predictive modeling for estimating bacterial viability, because traditional microbiological enumeration is a time-consuming and laborious method. The accuracy and speed of artificial neural networks (ANNs) for this purpose is an attractive alternative (developed from predictive microbiology), especially for on-line processing in industry. Data from a study of interactive effects of different levels of pH, water activity, and the concentrations of allyl isothiocyanate at various times during sausage manufacture in reducing numbers of E. coli O157:H7 were collected. Data were used to develop predictive models using a general regression neural network (GRNN), a form of ANN, and a statistical linear polynomial regression technique. Both models were compared for their predictive error, using various statistical indices. GRNN predictions for training and test data sets had less serious errors when compared with the statistical model predictions. GRNN models were better and slightly better for training and test sets, respectively, than was the statistical model. Also, GRNN accurately predicted the level of allyl isothiocyanate required, ensuring a 5-log reduction, when an appropriate production set was created by interpolation. Because they are simple to generate, fast, and accurate, ANN models may be of value for industrial use in dry fermented sausage manufacture to reduce the hazard associated with E. coli O157:H7 in fresh beef and permit production of consistently safe products from this raw material.

scholarly journals Cotrimoxazole-ResistantEscherichia coliBacteremia in Neutropenic Patients at a Regional Oncology Hospital

1992 ◽  
Vol 3 (1) ◽  
pp. 14-18
Author(s):  
Daniel B Gregson ◽  
Anne G Matlow ◽  
Andrew E Simor ◽  
Peter G Tuffnell ◽  
Donald E Low ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Marrow Transplant ◽  
Single Strain ◽  
Gram Negative ◽  
E Coli ◽  
Staff Members ◽  
Cotrimoxazole Prophylaxis ◽  
Neutropenic Patients ◽  
Chemotherapy Induced Neutropenia ◽  
High Level

In a regional oncology hospital using cotrimoxazole (trimethoprim-sulphamethoxazole) prophylaxis during chemotherapy-induced neutropenia, a single strain ofEscherichia coli(indole negative) caused 15 of 27 episodes of Gram-negative rod bacteremia in 1987, and four of 32 such episodes in 1988. This biotype had not been recovered in 1986. Investigations during this ‘outbreak’ of bacteremias revealed enteric colonization with this strain ofE coliin 37% of patients on leukemia or bone marrow transplant wards and in several staff members in July 1987. In 1988, 11 of 32 Gram-negative rod bacteremias were secondary to other strains of indole positiveE coliof several different biotypes and plasmid profiles. Indole negative strains all exhibited low level trimethoprim resistance, whereas indole positive strains which subsequently appeared exhibited high level trimethoprim resistance. Failure of cotrimoxazole prophylaxis was initially due to the clonal dissemination of a single strain ofE coliwithin the institution, with the subsequent appearance of multipleE colistrains with probable differing genetic bases for their resistance.

Survival of Escherichia coli O157:H7 in Ground-Beef Patties during Storage at 2, −2, 15 and then −2°C, and −20°C†

1999 ◽  
Vol 62 (11) ◽  
pp. 1243-1247 ◽  
Author(s):  
SUSAN E. ANSAY ◽  
KIM A. DARLING ◽  
CHARLES W. KASPAR
Keyword(s):  
Escherichia Coli ◽  
Frozen Storage ◽  
Ground Beef ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Control Strain ◽  
Single Strain ◽  
E Coli ◽  
Beef Patties ◽  
Significant Difference

The survival of Escherichia coli O157:H7 and of a nonpathogenic control strain of E. coli was monitored in raw ground beef that was stored at 2°C for 4 weeks, −2°C for 4 weeks, 15°C for 4 h and then −2°C for 4 weeks, and −20°C. Irradiated ground beef was inoculated with one E. coli control strain or with a four-strain cocktail of E. coli O157:H7 (ca. 105 CFU/g), formed into patties (30 to 45 g), and stored at the appropriate temperature. The numbers of the E. coli control strain decreased by 1.4 log10 CFU/g, and pathogen numbers declined 1.9 log10 CFU/g when patties were stored for 4 weeks at 2°C. When patties were stored at −2°C for 4 weeks, the numbers of the E. coli control strain and the serotype O157:H7 strains decreased 2.8 and 1.5 log10 CFU/g, respectively. Patties stored at 15°C for 4 h prior to storage at −2°C for 4 weeks resulted in 1.6 and 2.7 log10–CFU/g reduction in the numbers of E. coli and E. coli O157:H7, respectively. Storage of retail ground beef at 15°C for 4 h (tempering) did not result in increased numbers of colony forming units per gram, as determined with violet red bile, MRS lactobacilli, and plate-count agars. Frozen storage (−20°C) of ground-beef patties that had been inoculated with a single strain of E. coli resulted in approximately a 1 to 2 log10–CFU/g reduction in the numbers of the control strain and individual serotype O157:H7 strains after 1 year. There was no significant difference between the survival of the control strain and the O157:H7 strains, nor was there a difference between O157:H7 strains. These data demonstrate that tempering of ground-beef patties prior to low-temperature storage accelerated the decline in the numbers of E. coli O157:H7.

scholarly journals Escherichia coliflagellar serotyping is as reliable as it has always been!

1987 ◽  
Vol 98 (2) ◽  
pp. 221-222 ◽  
Author(s):  
Frits Ørskov ◽  
Ida Ørskov ◽  
K. A. Bettelheim
Keyword(s):  
Escherichia Coli ◽  
Dna Analysis ◽  
Epidemiological Evidence ◽  
Single Strain ◽  
E Coli ◽  
Electrophoretic Patterns ◽  
Cast Doubt ◽  
The Stability ◽  
H Serotypes

In a recent paper in this Journal by Marshallet al.(1985), which described the bacterial endonuclease DNA analysis (BRENDA) of severalEscherichia coli0126 strains, the following statement was found in the summary: ‘The isolates from the outbreak produced indistinguishable DNA electrophoretic patterns in spite of their assignment to seven different H serotypes… These results support the epidemiological evidence that a single-strain outbreak had occurred, and they cast doubt on the value of H typing for this particular investigation.’ The same 0126 strains that were enterotoxigenic (ST) were treated in two earlier papers (Bettelheim & Reeve, 1982; Bettelheim, 1984) and also on these two earlier occasions the authors raised doubt about the stability ofE. coliH typing results.

scholarly journals Long-Term Colonization byblaCTX-M-Harboring Escherichia coli in Healthy Japanese People Engaged in Food Handling

2016 ◽  
Vol 82 (6) ◽  
pp. 1818-1827 ◽  
Author(s):  
Kunihiko Nakane ◽  
Kumiko Kawamura ◽  
Kensuke Goto ◽  
Yoshichika Arakawa
Keyword(s):  
Escherichia Coli ◽  
Agar Plate ◽  
Actual State ◽  
Japanese People ◽  
Content Type ◽  
E Coli ◽  
Synergy Test ◽  
Esbl Producers ◽  
M 14

ABSTRACTThe actual state of intestinal long-term colonization by extended-spectrum β-lactamase (ESBL)-producingEscherichia coliin healthy Japanese people remains unclear. Therefore, a total of 4,314 fecal samples were collected from 2,563 food handlers from January 2010 to December 2011. Approximately 0.1 g of each fecal sample was inoculated onto a MacConkey agar plate containing cefotaxime (1 μg/ml). The bacterial colonies that grew on each plate were checked for ESBL production by the double-disk synergy test, as recommended by the Clinical and Laboratory Standards Institute. The bacterial serotype, antimicrobial susceptibility, pulsotype, sequence type (ST), and ESBL genotype were checked, and the replicon types of plasmids harboring the ESBL gene were also determined after conjugation experiments. ESBL producers were recovered from 70 (3.1%) of 2,230 participants who were checked only once. On the other hand, ESBL producers were isolated at least once from 52 (15.6%) of 333 participants who were checked more than twice, and 13 of the 52 participants carried ESBL producers for from more than 3 months to up to 2 years. Fluoroquinolone (FQ)-resistantE. colistrains harboringblaCTX-Mwere repeatedly recovered from 11 of the 13 carriers ofblaCTX-M-harboringE. coli. A genetically related FQ-resistantE. coliO25b:H4-ST131 isolate harboringblaCTX-M-27was recovered from 4 of the 13 carriers for more than 6 months. Three FQ-resistantE. coliO1:H6-ST648 isolates that harboredblaCTX-M-15orblaCTX-M-14were recovered from 3 carriers. Moreover, multiple CTX-M-14- or CTX-M-15-producingE. coliisolates with different serotypes were recovered from 2 respective carriers. These findings predict a provable further spread of ESBL producers in both community and clinical settings.

scholarly journals Longitudinal Emergence and Distribution of Escherichia coli O157 Genotypes in a Beef Feedlot

2006 ◽  
Vol 72 (12) ◽  
pp. 7614-7619 ◽  
Author(s):  
Michael W. Sanderson ◽  
Jan M. Sargeant ◽  
Xiarong Shi ◽  
T. G. Nagaraja ◽  
Ludek Zurek ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Feedlot Cattle ◽  
Longitudinal Distribution ◽  
Single Strain ◽  
Fecal Samples ◽  
E Coli ◽  
Before And After ◽  
Water Tanks ◽  
Feed Samples ◽  
Bird Feces

ABSTRACT The purpose of this study was to describe the prevalence and longitudinal distribution of Escherichia coli O157 in feedlot cattle and the feedlot environment. Pen floors, water tanks, other cattle in the feedlot, feed, and bird feces were sampled for 2 weeks prior to entry of the study cattle. Twelve pens of study cattle were sampled twice weekly. At each sample time cattle feces, water from tanks in each pen, bunk feed, feed components, bird feces, and houseflies were collected. Bunk feed samples were collected before and after cattle had access to the feed. Overall, 28% of cattle fecal samples, 3.9% of bird fecal samples, 25% of water samples, 3.4% of housefly samples, 1.25% of bunk feed before calf access, and 3.25% of bunk feed samples after cattle had access to the feed were positive for E. coli O157. Genetic analysis of E. coli O157 isolates was done using pulsed-field gel electrophoresis (PFGE). PFGE types identified in sampling of the feedlot prior to calf entry were different than the majority of types identified following calf entry. A single strain type predominated in the samples collected after entry of the cattle. It was first identified 5 days after entry of the first pen of cattle and was subsequently identified in all pens. Data support that the incoming cattle introduced a new strain that became the predominant strain in the feedlot.

Sign in / Sign up

Export Citation Format

Share Document