Comparison of Resistance to Microbial Contamination of Conventional and Modified Water Dispensers

1992 ◽  
Vol 55 (8) ◽  
pp. 627-631 ◽  
Author(s):  
KARL F. ECKNER
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Detection Limit ◽  
Microbial Contamination ◽  
Inoculum Level ◽  
E Coli ◽  
Test Organisms ◽  
Level 3 ◽  
High Level ◽  
Very High

Water dispensers with traditional, open reservoirs were tested comparatively against modified, closed reservoirs and modified caps to determine their failure to resist contamination from exterior surfaces of water bottles and aerosols. Bottle rims and caps were surface inoculated with Escherichia coli (SLR 51), Staphylococcus aureus (SLR 717), and Pseudomonas fluorescens (ATCC 13525) at levels approximating 1 × 107 to 1 × 108 cells for a high level and 1 × 103 cells for a low level. The bottles contained 2,000 ml of water. After mounting the bottles on the appropriate water dispenser type, all water was withdrawn from the units 24 h later. Levels of test organisms recovered ranged from 5.0 × 103 to 4.5 × 105 CFU/ml for the high inoculum and 0.39 to 0.84 CFU/ml for the low inoculum in the traditional water dispensing unit. No test organisms (detection limit <0.01 CFU/ml) were recovered from the modified water dispenser for either high or low inoculum level when the unit was sanitized between trials. Test microorganisms were recovered at levels of ≈ 0.06 CFU/ml to ≈0.8 CFU/ml after 3–5 repetitions of very high level (3 × 108 CFU/ml) inoculation with E. coli and S. aureus without sanitization between trials. An aerosol of 2.02 × 109 CFU E. coli per ml was generated in a chamber directly over the water dispensers without bottles mounted for one trial. The modified water dispenser reduced aerosol contamination by 100- to 1,000-fold.

Survival of Escherichia coli O157:H7, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes in Kimchi

2004 ◽  
Vol 67 (7) ◽  
pp. 1497-1500 ◽  
Author(s):  
Y. INATSU ◽  
M. L. BARI ◽  
S. KAWASAKI ◽  
K. ISSHIKI
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Incubation Period ◽  
Salmonella Enteritidis ◽  
Detectable Level ◽  
Escherichia Coli O157 ◽  
Inoculum Level ◽  
Initial Inoculum ◽  
E Coli

The survival of gram-positive and gram-negative foodborne pathogens in both commercial and laboratory-prepared kimchi (a traditional fermented food widely consumed in Japan) was investigated. It was found that Escherichia coli O157:H7, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes could survive in both commercial and laboratory-prepared kimchi inoculated with these pathogens and incubated at 10°C for 7 days. However, when incubation was prolonged, the S. aureus level decreased rapidly from the initial inoculum level to the minimum detectable level within 12 days, whereas Salmonella Enteritidis and L. monocytogenes took 16 days to reach similar levels in commercial kimchi. On the other hand, E. coli O157:H7 remained at high levels throughout the incubation period. For laboratory-prepared kimchi, the S. aureus level decreased rapidly from the initial inoculum level to the minimum detectable level within 12 days, and L. monocytogenes took 20 days to reach a similar level. E. coli O157:H7 and Salmonella Enteritidis remained at high levels throughout the incubation period. The results of this study suggest that the contamination of kimchi with E. coli O157:H7, Salmonella Enteritidis, S. aureus, or L. monocytogenes at any stage of production or marketing could pose a potential risk.

Bactericidal Effects of Lactobacillus reuteri and Allyl Isothiocyanate on Escherichia coli O157:H7 in Refrigerated Ground Beef

2003 ◽  
Vol 66 (11) ◽  
pp. 2038-2044 ◽  
Author(s):  
PARTHIBAN MUTHUKUMARASAMY ◽  
JUNG H. HAN ◽  
RICHARD A. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Lactobacillus Reuteri ◽  
Ground Beef ◽  
Storage Period ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
Inoculum Level ◽  
E Coli ◽  
Level 3

Two naturally occurring antimicrobial agents were tested in packages of refrigerated ground beef for their ability to reduce the viability of Escherichia coli O157:H7 during storage. Allyl isothiocyanate (AITC) and Lactobacillus reuteri were tested separately and together for their action against a cocktail of five strains of E. coli O157:H7 in ground beef held at 4°C for 25 days. Ground beef prepared from whole, raw inside round beef roasts was inoculated with low (3 log CFU/g) or high (6 log CFU/g) levels of the E. coli O157:H7 mixture. The beef was treated with AITC (about 1,300 ppm), L. reuteri, or both, along with 250 mM of glycerol per kg of meat at two levels (3 and 6 log CFU/g) and according to a design that yielded 8 controls plus 10 different treatments. Samples were analyzed for E. coli O157:H7 survivors, numbers of total bacteria, and lactic acid bacteria on days 0 to 25 at 5-day intervals. L. reuteri at both input levels with glycerol killed E. coli O157:H7 at both inoculated levels before day 20. AITC completely eliminated E. coli O157:H7 at the low-inoculum level (3 log CFU/g) and reduced viability >4.5 log CFU/g at the high-inoculum level (6 log CFU/g) by the end of the storage period. The combination of L. reuteri and AITC did not yield an additive effect against E. coli O157:H7 viability. L. reuteri in the presence of glycerol was highly effective against E. coli O157:H7 in ground beef during refrigerated storage (4°C) in modified atmosphere packages. Sensory testing is planned to evaluate effects of treatments.

scholarly journals Antibacterial effect of Aqueous Neem (Azadirachta indica) leaf extract, crude neem leaf paste, and Ceftriaxone against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa

2016 ◽  
Vol 3 (1) ◽  
pp. 25-36
Author(s):  
Shamima Sultana ◽  
A. S. M. Shahidullah ◽  
Md. Mahbubul Islam ◽  
A. F. S. A. Wasey ◽  
Shamsun Nahar
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Leaf Extract ◽  
Inhibitory Effects ◽  
Dilution Technique ◽  
E Coli ◽  
Test Organisms ◽  
Broth Dilution

The study was conducted during the period of July 2004 to June 2005 in the   Department of Pharmacology & Therapeutics in collaboration of Department of Microbiology, Mymensingh Medical College, Mymensingh to determine the profile of antibacterial effect of crude neem leaf paste (CNLP), aqueous neem leaf extract (ANLE), and standard antibiotic Ceftriaxone against Staphylococcus aureus, Escherichia coli and, Pseudomonas aeruginosa. Five separate experiments were done e.g. I) Determination of inhibitory effect of crude neem leaf paste (CNLP) by incorporation into nutrient agar media (NA), against Staphylococcus aureus, Escherichia coli and, Pseudomonas aeruginosa. II) Determination of minimum inhibitory concentration (MIC) of aqueous neem leaf extract (ANLE) against that three test organisms by broth dilution technique, III) Determination of minimum inhibitory concentration (MIC) of standard antibiotic ceftriaxcone against test organisms by broth dilution technique as well as making a comparison with MIC of ANLE and IV) Subculture study of materials from effective CNLP, ANLE, NLEE and Ceftriaxone in nutrient agar medium for confirmation of respective results of different experiments conducted. Results revealed that inhibitory effects were observed against the growth of Staph. aureus, Esch. coli and Ps. aeruginosa at 15%, 20% and 25% respectively of CNLP incorporated  into NA media.  The broth dilution technique was followed to determine the MICs of ANLE and Ceftriaxone. The MIC of ANLE was 714 μg/ml against S. aureus and that against E. coli and P. aeruginosa was 1428 μg/ml. The MIC of Ceftriaxone was 10μg/ml against S. aureus and that against E. coli and P. aeruginosa was 25 μg/ml. The MIC of Ceftriaxone was the lowest in comparison to MICs of ANLE. The subculture study showed similar results with that of previous experiments in terms of inhibitory effects of CNLP and MICs of ANLE, Ceftriaxone against all of the organisms studied.  

scholarly journals Germicidal Activities of Some Selected Disinfectants on Staphylococcus aureus and Escherichia Coli

2020 ◽  
Vol 5 (2) ◽  
pp. 1-5
Author(s):  
Celestina MI
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Inhibitory Activity ◽  
Diffusion Method ◽  
Zone Of Inhibition ◽  
E Coli ◽  
Test Organisms ◽  
And Staphylococcus Aureus ◽  
Mic Value ◽  
Pathogenic Infection

The germicidal efficacy of four common disinfectants used for different purposes was tested against two common pathogens namely Escherichia coli and Staphylococcus aureus . The disinfectants (Dettol, Jik, Izal and Purit) were diluted with sterile distilled water to achieve different concentrations (100%, 50%, 25%, 12.5% and 6.25%) and they were tested on the two organisms using Agar well diffusion method. The plates were allowed to incubate for 24 hours at 37°C.The germicidal efficiency of the disinfectants was evaluated by measuring the zone of inhibition of each disinfectant based on their varying concentrations. Dettol was observed to have the highest inhibition at 100% concentration and was more germicidal on E. coli than S. aureus with Minimal Inhibitory Concentration (MIC) value of 1:16 dilution against the two test organisms. This was closely followed by Jik which also showed more inhibitory activity against E. coli at the initial concentration recording the second highest inhibition rate compared to other disinfectants, but its efficacy decreased as the concentration dropped. Jik exhibited MIC value of 1:8 and 1:2 dilutions for Staphylococcus aureus and Escherichia coli respectively. Purit showed more inhibitory activity on S. aureus with 3.8mm zone of inhibition as against 1.3mm at 100% concentration, recording MIC value of 1:8 dilution on S. aureus and 1:16 dilution for E. coli . The disinfectant Izal was observed to be the lowest as it did not inhibit the growth of any of the organisms, indicating resistance of the organisms to the disinfectant at all concentrations. All the disinfectants apart from Izal inhibited the two test isolates. Only Dettol proved to be best among them. Therefore, Dettol is encouraged to be used in homes to prevent pathogenic infection.

scholarly journals Surveillance and Reduction Control of Escherichia coli and Diarrheagenic E. coli During the Pig Slaughtering Process in China

2021 ◽  
Vol 8 ◽  
Author(s):  
Lin Wang ◽  
Na Liu ◽  
Yubin Gao ◽  
Junhui Liu ◽  
Xiumei Huang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Microbial Contamination ◽  
Human Life ◽  
Current Status ◽  
E Coli ◽  
Positive Ratio ◽  
Microbiological Testing ◽  
Positive Rate ◽  
Very High

The microbial contamination of pork during the slaughter process, especially that of the hygiene indicator bacteria, Escherichia coli, is closely related to the safety and quality of the meat. Some diarrheagenic E. coli can cause serious foodborne diseases, and pose a significant threat to human life and health. In order to ascertain the current status of E. coli and diarrheagenic E. coli contamination during the pig slaughter process in China, we conducted thorough monitoring of large-sized slaughterhouses, as well as small- or medium-sized slaughterhouses, in different provinces of China from 2019 to 2020. The overall positive rate of E. coli on the pork surface after slaughter was very high (97.07%). Both the amount of E. coli contamination and the positive ratio of diarrheagenic E. coli in large-sized slaughterhouses (7.50–13.33 CFU/cm2, 3.44%) were lower than those in small- or medium-sized slaughterhouses (74.99–133.35 CFU/cm2, 5.71%). Combined with the current status of sanitary control in slaughterhouses, we determined that pre-cooling treatment significantly reduced E. coli and diarrheagenic E. coli in pork after slaughter, while microbiological testing reduced E. coli. Based on our monitoring data, China urgently needs to establish relevant standards to better control microbial contamination during pig slaughtering progress. This study provided a theoretical basis for the hygiene quality management of the pig slaughter industry in China.

scholarly journals Phytochemical Screening and Antibacterial Activity of the Crude Extract of Scent Leaf (Ocimum gratissimum) on Escherichia coli and Staphylococcus aureus

2020 ◽  
pp. 1-7
Author(s):  
I. I. Hamma ◽  
I. Y. Tafinta ◽  
A. Abdulmalik ◽  
J. Theophilus ◽  
M. Abubakar
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Aqueous Extract ◽  
Ethanol Extract ◽  
Phytochemical Screening ◽  
E Coli ◽  
Ocimum Gratissimum ◽  
Test Organisms ◽  
And Staphylococcus Aureus

Scent (Ocimum gratissimum) leaves are known for their medicinal values for a long. The study was carried out on phytochemical screening and antibacterial activity of scent leaf extracts on E. coli and S. aureus. Antibacterial assay of the plant extracts was carried out on the test isolates, by inoculation on the surface of freshly gelled sterile nutrient agar plates by streaking using sterilized swab stick and the potent extracts was determined according to the macro broth dilution technique. Phytochemical screening of O. gratissimum leaves revealed the presence of steroids, saponins, flavonoids, alkaloids, cardiac glycosides and tannins in all the extracts. There was decreased in antibacterial activity with decreased in concentration of the extract as the concentration of the extract decreases from 200 – 25 mg/ml, the zones of inhibition also decreased from 20 to 11 mm (ethanol extract) and 17 – 10 mm (aqueous extract) for S. aureus; 19 – 10 mm (ethanol extract) and 15 – 8 mm (aqueous extract) for E. coli. The Minimum Inhibitory Concentration (MIC) of O. gratissimum extracts against the selected clinical isolates revealed no growth (clear) in all the test organisms at the concentration of 200 mg/ml. Also, the Minimum Bactericidal Concentration (MBC) showed no growth of bacterial colonies at the concentration of 200 mg/ml. It was observed from the study that ethanol and aqueous extracts exhibited high inhibitory activities on Escherichia coli a representative of enteric coliforms and Gram negative bacteria and Staphylococcus aureus a representative of Gram positive bacteria. Ethanolic extract had higher inhibition compared to the aqueous extract. This can be deduced to the ability of ethanol to extract more of the essential oils and secondary plant metabolites which are believed to exert antibacterial activity on the test organisms.

scholarly journals Ability of Shiga Toxin-Producing Escherichia coli and Salmonella spp. To Survive in a Desiccation Model System and in Dry Foods

2005 ◽  
Vol 71 (11) ◽  
pp. 6657-6663 ◽  
Author(s):  
Reiji Hiramatsu ◽  
Masakado Matsumoto ◽  
Kenji Sakae ◽  
Yutaka Miyazaki
Keyword(s):  
Escherichia Coli ◽  
Detection Limit ◽  
Shiga Toxin ◽  
Survival Rates ◽  
Model System ◽  
Bacterial Strains ◽  
Salmonella Spp ◽  
Inoculum Level ◽  
E Coli ◽  
Subsequent Storage

ABSTRACT In order to determine desiccation tolerances of bacterial strains, the survival of 58 diarrheagenic strains (18 salmonellae, 35 Shiga toxin-producing Escherichia coli [STEC], and 5 shigellae) and of 15 nonpathogenic E. coli strains was determined after drying at 35°C for 24 h in paper disks. At an inoculum level of 107 CFU/disk, most of the salmonellae (14/18) and the STEC strains (31/35) survived with a population of 103 to 104 CFU/disk, whereas all of the shigellae (5/5) and the majority of the nonpathogenic E. coli strains (9/15) did not survive (the population was decreased to less than the detection limit of 102 CFU/disk). After 22 to 24 months of subsequent storage at 4°C, all of the selected salmonellae (4/4) and most of the selected STEC strains (12/15) survived, keeping the original populations (103 to 104 CFU/disk). In contrast to the case for storage at 4°C, all of 15 selected strains (5 strains each of Salmonella spp., STEC O157, and STEC O26) died after 35 to 70 days of storage at 25°C and 35°C. The survival rates of all of these 15 strains in paper disks after the 24 h of drying were substantially increased (10 to 79 times) by the presence of sucrose (12% to 36%). All of these 15 desiccated strains in paper disks survived after exposure to 70°C for 5 h. The populations of these 15 strains inoculated in dried foods containing sucrose and/or fat (e.g., chocolate) were 100 times higher than those in the dried paper disks after drying for 24 h at 25°C.

scholarly journals High-level expression of human dihydropteridine reductase (EC 1.6.99.7), without N-terminal amino acid protection, in Escherichia coli

1989 ◽  
Vol 261 (1) ◽  
pp. 265-268 ◽  
Author(s):  
W L F Armarego ◽  
R G H Cotton ◽  
H H Dahl ◽  
N E Dixon
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Dihydropteridine Reductase ◽  
Terminal Amino Acid ◽  
High Level Expression ◽  
E Coli ◽  
Human Enzyme ◽  
Terminal Amino ◽  
High Level ◽  
Very High

The cDNA coding for human dihydropteridine reductase [Dahl, Hutchinson, McAdam, Wake, Morgan & Cotton (1987) Nucleic Acids Res. 15, 1921-1936] was inserted downstream of tandem bacteriophage lambda PR and PL promoters in Escherichia coli vector pCE30. Since pCE30 also expresses the lambda c1857ts gene, transcription may be controlled by variation of temperature. The recombinant plasmid in an E. coli K12 strain grown at 30 degrees C, then at 45 degrees C, directed the synthesis of dihydropteridine reductase to very high levels. The protein was soluble, at least as active as the authentic human enzyme, and lacked the N-terminal amino acid protection.

scholarly journals Evaluation of the Antibacterial Effectiveness of Some Antiseptics and Disinfectants

2021 ◽  
Vol 6 (1) ◽  
pp. 175-181
Author(s):  
A. I. Aminu ◽  
◽  
M. S. Abdullahi
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Inhibition Zone ◽  
Bacterial Isolates ◽  
E Coli ◽  
Test Organisms ◽  
Inhibition Zones ◽  
Key Words Evaluation ◽  
Klebsiella Spp

Application of disinfectants and antiseptics continue to be an essential part of infection control practices; as such there is the need for constant evaluation of their effectiveness. The study aimed at evaluating the antibacterial effectiveness of some brands of disinfectants and antiseptics against some bacterial isolates. Two disinfectants-D1 (Sodium hypochlorite 3.85%) and D2 (7% Tar acid, phenol, 2% cresylic creosote) and two antiseptics-A1 (Chloroxyenol B.Pc 48%nw/v, oleumpiniaromgticum 8.3%w/w) and A2 (Dichlorometaxylenol, IPA, terpinol) were selected and their efficacies against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella spp and Escherichia coli were determined using agar disk diffusion methods. The potency of the disinfectants was further evaluated against phenol to establish the phenol coefficient (Pc). The result revealed that both the disinfectants and the antiseptics inhibited the different test organisms at various concentrations producing higher inhibition zones at higher concentrations (P=0.001) that differ significantly with the type of agent used (P=0.007).Both agents produces higher inhibitions zones against S. aureus, Klebsiella spp, E. coli and the least inhibition zones against P. aeruginosa. At 100% concentration, D1 produces the highest inhibition zone of 21mm against E. coli, while A1produces the highest inhibition zones of 17mm against E. coli, S. aureus and Klebsiella spp. The result indicated that both disinfectants (D1 and D2) are more effective than phenol and that D1 is more effective than D2 with Pc coefficient of 3.0 and 2.0 against S. aureus and P. aeruginosa respectively compared to D2 with a Pc of 2.0 and 1.05 against S. aureus and P. aeruginosa. The study identifies that both disinfectants and antiseptics especially D1 and A1 were effective against the test isolates except for P. aeruginosa which was less susceptible. Key words: Evaluation, Disinfectants, Antiseptics, Bacteria

scholarly journals Identification of Escherichia coli Genes Essential for High-Level, Clinically Relevant, Resistance to Antibiotics

2021 ◽  
Author(s):  
Esmeralda Z Reyes Fernandez ◽  
Noemie Alon Cudkowicz ◽  
Sonia Steiner Mordoch ◽  
Shimon Schuldiner
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Molecular Mechanisms ◽  
E Coli ◽  
Novel Approach ◽  
Public Health Challenges ◽  
High Concentrations ◽  
New Perspective ◽  
High Level ◽  
Very High

Antibiotic resistance is one of the biggest public health challenges of our time. Here we present a novel approach to recognizing molecular mechanisms essential for maintaining high-level clinically relevant antibiotic resistance. To identify essential genes in this context, we subjected Escherichia coli EV18, a strain highly resistant to quinolones, to random transposon mutagenesis. This strain's unique advantage is that the screen is performed at very high concentrations of the antibiotic, non-permissive for most strains. The transposon's insertion affected the transcription of five genes required for the maintenance of resistance in EV18. Three of these genes (YihO, YhdP, and WaaY) have not been previously identified as essential for high-level antimicrobial resistance (AMR). Our work provides a new perspective to identify and characterize novel players crucial for maintaining AMR in E. coli.

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