Comparison of the β-Glucuronidase Assay and the Conventional Method for Identification of Escherichia coli on Eosin-Methylene Blue Agar

1997 ◽  
Vol 60 (1) ◽  
pp. 6-9 ◽  
Author(s):  
SHIU W. HUANG ◽  
CHUNG H. CHANG ◽  
TUNG F. TAI ◽  
TSUNG C. CHANG

The purpose of this study was to compare the IMViC (indole, methyl red, Voges-Proskauer and citrate utilization) tests with the β-glucuronidase (GUD) assay for the identification of suspect Escherichia coli on Levine's eosin-methylene blue (EMB) agar. After testing 258 suspect E. coli colonies from raw meat and meat products, 163 and 44 were found to be E. coli and non-E. coli, respectively, by both methods. Nine isolates were IMViC positive (i.e., + + − − or − + − −) but GUD negative; among these isolates, six were confirmed to be E. coli by API 20E (bioMérieux, Marcy-I'Etoile, France) with the remaining three being non-E. coli. There were 42 isolates that were IMViC negative but GUD positive; among these isolates, seven were pure E. coli cultures, 33 were mixed cultures containing E. coli, and the remaining two were Proteus spp. The sensitivities for the identification of E. coli on EMB were 80.9% (169/209) and 97.1% (203/209), respectively, by the IMViC tests and GUD assay; whereas the specificities were 93.9% (46/49) and 95.9% (47/49), respectively, by the IMViC tests and GUD assay. It is proposed that the GUD assay can be an effective alternative to the conventional IMViC tests for the identification of suspect E. coli on EMB.

2008 ◽  
Vol 71 (10) ◽  
pp. 2082-2086 ◽  
Author(s):  
LUCIANO BENEDUCE ◽  
GIUSEPPE SPANO ◽  
ARI Q. NABI ◽  
FRANCESCO LAMACCHIA ◽  
SALVATORE MASSA ◽  
...  

In this study, 100 raw meat samples were collected from 15 local Moroccan butcheries in five different areas of the city of Rabat during a period of 4 months. Overall, 7 of 15 butcheries from three areas of the city yielded strains of Escherichia coli O157. Single isolates from 9 (9%) of 100 raw meat samples were biochemically and serologically confirmed as E. coli O157. Using molecular techniques, two strains were positive for the Shiga toxin, with two additional strains containing an attaching-effacing gene. All potentially virulent serotypes isolated from these meat samples showed distinct pulsed-field gel electrophoresis profiles. Based on antibiotic susceptibility testing, more than 70% of the isolates were resistant to ampicillin and clavulanic acid–amoxicillin. Moreover, one strain was resistant to more than three antibiotics. Our study represents the first survey of E. coli O157 and related serotypes in raw meat products in Morocco.


1993 ◽  
Vol 27 (3-4) ◽  
pp. 267-270 ◽  
Author(s):  
M. T. Augoustinos ◽  
N. A. Grabow ◽  
B. Genthe ◽  
R. Kfir

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.


1999 ◽  
Vol 62 (10) ◽  
pp. 1115-1122 ◽  
Author(s):  
A. E. HEUVELINK ◽  
J. T. M. ZWARTKRUIS-NAHUIS ◽  
R. R. BEUMER ◽  
D E. de BOER

In 1996 and 1997, 2,941 fresh and processed meat products obtained from supermarkets and butcher shops in The Netherlands were examined for the presence of verocytotoxin-producing Escherichia coli of serogroup O157 (O157 VTEC). Additionally, the fate of O157 VTEC in raw meat products stored at low temperatures and the effect of different additives were evaluated. O157 VTEC strains were isolated from 6 (1.1%) of 571 samples of raw minced beef, 2 (0.5%) of 402 samples of raw minced mixed beef and pork, 1 (1.3%) of 76 samples of raw minced pork, 1 (0.3%) of 393 samples of other raw pork products, and 1 (0.3%) of 328 samples of cooked or fermented ready-to-eat meats. Other raw beef products (n = 223) and meat samples originating from poultry (n = 819), sheep or lamb (n = 46), or wild animals (n = 83) were all found to be negative for O157 VTEC. For the survival experiments we used tartaar (minced beef with a fat content of less than 10%) and filet americain (tartaar mixed with a mayonnaise-based sauce [80 to 20%]). The O157 VTEC strain tested was able to survive in tartaar and filet americain stored at −20, 0, 5, or 7°C for 3 days. At both 7 and at 15°C, O157 VTEC counts in tartaar and filet americain remained virtually unchanged throughout a storage period of 5 days. Addition of acetic acid (to pH 4.0), sodium lactate (1 and 2% [wt/wt]), or components of the lactoperoxidase–thiocyanate–hydrogen peroxide system to filet americain did not result in a reduction of viable O157 VTEC cells during storage at 7 or 15°C. It was concluded that raw meat contaminated with O157 VTEC will remain a hazard even if the meat is held at low or freezing temperatures.


1991 ◽  
Vol 54 (7) ◽  
pp. 496-501 ◽  
Author(s):  
ARTHUR HINTON ◽  
GEORGE E. SPATES ◽  
DONALD E. CORRIER ◽  
MICHAEL E. HUME ◽  
JOHN R. DELOACH ◽  
...  

A Veillonella species and Enterococcus durans were isolated from the cecal contents of adult broilers. Mixed cultures of Veillonella and E. durans inhibited the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on media containing 2.5% lactose (w/v). The growth of S. typhimurium or E. coli 0157:H7 was not inhibited by mixed cultures containing Veillonella and E. durans on media containing only 0.25% lactose or by pure cultures of Veillonella or E. durans on media containing either 0.25% or 2.5% lactose. The mixed cultures of Veillonella and E. durans produced significantly (P<0.05) more acetic, propionic, and lactic acids in media containing 2.5% lactose than in media containing 0.25% lactose. The inhibition of the enteropathogens was related to the production of lactic acid from lactose by the E. durans and the production of acetic and propionic acids from lactic acid by the Veillonella.


2004 ◽  
Vol 132 (2) ◽  
pp. 283-289 ◽  
Author(s):  
D. M. MacDONALD ◽  
M. FYFE ◽  
A. PACCAGNELLA ◽  
A. TRINIDAD ◽  
K. LOUIE ◽  
...  

An outbreak of E. coli O157:H7 infections was identified in November 1999 with a fivefold increase in the occurrence of laboratory-confirmed cases of E. coli O157:H7 infection. A matched case-control study was conducted. Samples of food from cases and from retailers were analysed for the presence of E. coli O157:H7. A total of 143 cases were identified over a 12-week period with the same pulsed-field gel electrophoresis (PFGE) pattern. The case-control study found that Company A salami was significantly associated with illness (Mantel–Haenszel matched odds ratio 10·0, 95% CI 1·4–434, P=0·01). Company A salami tested positive for E. coli O157:H7 and isolates had the same PFGE pattern as case isolates. An immediate voluntary national recall of Company A dry fermented meat products took place. Findings from the investigation of this outbreak suggest that the hold-and-test option may not be adequate to prevent shiga-toxigenic Escherichia coli (STEC) infection in salami consumers.


Author(s):  
Md. Shahin Azad ◽  
Syaza Azhari ◽  
Mohd Sukri Hassan

The utilization of biopolymer derived from Moringa oleifera bark using ZnCl2 and H2SO4 as activating agents for eliminating Methylene blue, Escherichia coli and Pseudomonas aeruginosa from producing wastewater. In this study, Methylene blue and both bacteria were effectively adsorbed by activated carbon with lowest dosage. The activated carbon was prepared from natural-by product of Moringa oleifera bark by pyrolysis in a furnace at 700°C for 1 h. The characteristics of activated carbon have been determined using Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET), pHzpc (zero point charge), and FTIR spectroscopy. The obtained result were closely fitted with Freundlich isotherm model and adsorption kinetics follow the pseudo-second order model with the highest value of correlation coefficient (R2~1). Adsorption quantity was dose dependent and bacteria were maximum adsorbed using 10 mg of activated carbon as well as 25mg for methylene blue. The maximum adsorption capacity showed within 1 hour. The bacterial load was reduced by 98% for E. coli, 96% for P. aeruginosa as well as methylene blue reduced 94.2% from aqueous solution using batch adsorption methods. Adsorption process controlled by film diffusion mechanism. These result proposed that the activated carbon of Moringa oleifera can be used as a good adsorbent for the removal of Methylene blue, E. coli and P. aeruginosa.


RSC Advances ◽  
2015 ◽  
Vol 5 (119) ◽  
pp. 98325-98334 ◽  
Author(s):  
D. Zaharie-Butucel ◽  
J. Papp ◽  
C. Leordean ◽  
S. D. Anghel

A straightforward carbonaceous structure synthesis from methylene blue aided by Ar/He plasmas with different ordering and E. coli inhibition effects.


2017 ◽  
Vol 83 (6) ◽  
Author(s):  
James R. Johnson ◽  
Stephen B. Porter ◽  
Brian Johnston ◽  
Paul Thuras ◽  
Sarah Clock ◽  
...  

ABSTRACT Chicken meat products are hypothesized to be vehicles for transmitting antimicrobial-resistant and extraintestinal pathogenic Escherichia coli (ExPEC) to consumers. To reassess this hypothesis in the current era of heightened concerns about antimicrobial use in food animals, we analyzed 175 chicken-source E. coli isolates from a 2013 Consumer Reports national survey. Isolates were screened by PCR for ExPEC-defining virulence genes. The 25 ExPEC isolates (12% of 175) and a 2:1 randomly selected set of 50 non-ExPEC isolates were assessed for their phylogenetic/clonal backgrounds and virulence genotypes for comparison with their resistance profiles and the claims on the retail packaging label (“organic,” “no antibiotics,” and “natural”). Compared with the findings for non-ExPEC isolates, the group of ExPEC isolates had a higher prevalence of phylogroup B2 isolates (44% versus 4%; P < 0.001) and a lower prevalence of phylogroup A isolates (4% versus 30%; P = 0.001), a higher prevalence of multiple individual virulence genes, higher virulence scores (median, 11 [range, 4 to 16] versus 8 [range, 1 to 14]; P = 0.001), and higher resistance scores (median, 4 [range, 0 to 8] versus 3 [range, 0 to 10]; P < 0.001). All five isolates of sequence type 131 (ST131) were ExPEC (P = 0.003), were as extensively resistant as the other isolates tested, and had higher virulence scores than the other isolates tested (median, 12 [range, 11 to 13] versus 8 [range, 1 to 16]; P = 0.005). Organic labeling predicted lower resistance scores (median, 2 [range, 0 to 3] versus 4 [range, 0 to 10]; P = 0.008) but no difference in ExPEC status or virulence scores. These findings document a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates, including isolates from ST131, in retail chicken products in the United States, suggesting a potential public health threat. IMPORTANCE We found that among Escherichia coli isolates from retail chicken meat products purchased across the United States in 2013 (many of these isolates being extensively antibiotic resistant), a minority had genetic profiles suggesting an ability to cause extraintestinal infections in humans, such as urinary tract infection, implying a risk of foodborne disease. Although isolates from products labeled “organic” were less extensively antibiotic resistant than other isolates, they did not appear to be less virulent. These findings suggest that retail chicken products in the United States, even if they are labeled “organic,” pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates.


1971 ◽  
Vol 69 (4) ◽  
pp. 673-681 ◽  
Author(s):  
J. V. S. Pether ◽  
R. J. Gilbert

SUMMARYThe survival of salmonellas on the finger-tips is considered with reference to the ease with which they can be transferred to food by handling.Escherichia coli and several Salmonella serotypes were shown to survive on the finger-tips for various periods of time, for example, S. anatum could be recovered 3 hr. after artificially contaminating them with between 500 and 2000 organisms. S. anatum could also be recovered from the finger-tips after contaminating them with more than 6000 organisms followed by a 15 sec. hand-wash 10 min. later. Similarly, the survivors from minimal inocula of less than 100 S. anatum/finger-tip were, after 10 min., still capable of infecting samples of corned beef and ham. E. coli was isolated from the finger-tips of 13 of 110 butchers soon after they had left the meat line at a meat products factory, but was not detected on the finger-tips of 100 volunteers at the Central Public Health Laboratory.The implications of the present findings to the spread of salmonellas from raw to cooked foods, and the relevance of this to outbreaks of Salmonella infection in the general population and in hospitals, are discussed.


2008 ◽  
Vol 71 (8) ◽  
pp. 1679-1684 ◽  
Author(s):  
M. L. KHAITSA ◽  
J. OLOYA ◽  
D. DOETKOTT ◽  
R. KEGODE

The objective of this study was to quantify the role of class 1 integrons in antimicrobial resistance in Escherichia coli isolated from turkey meat products purchased from retail outlets in the Midwestern United States. Of 242 E. coli isolates, 41.3% (102 of 242) tested positive for class 1 integrons. A significant association was shown between presence of class 1 integrons in E. coli isolates and the resistance to tetracycline, ampicillin, streptomycin, gentamicin, sulfisoxazole, and trimethoprim-sulfamethoxazole. Attributable risk analysis revealed that for every 100 E. coli isolates carrying class 1 integrons, resistance was demonstrated for ampicillin (22%), gentamycin (48%), streptomycin (29%), sulfisoxazole (40%), trimethoprimsulfamethoxazole (7%), and tetracycline (26%). Non–integron-related antimicrobial resistance was demonstrated for ampicillin (65%), gentamycin (16.9%), streptomycin (42.1%), sulfisoxazole (35.8%), and tetracycline (49.7%). Population-attributable fraction analysis showed that class 1 integrons accounted for the following resistances: gentamycin, 71% (50 of 71), amoxicillin–clavulanic acid, 19.6% (6 of 33), nalidixic acid, 34% (7 of 21), streptomycin, 28% (30 of 107), sulfisoxazole, 38% (40 of 106), and tetracycline, 14%, (26 of 185). In conclusion, although class 1 integrons have been implicated in resistance to antimicrobial agents, other non–integron resistance mechanisms seem to play an important part.


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