scholarly journals Efficiency of Commercial Bacteriophages on Stec O157:H7 Populations in Beef Kept Under Vacuum and Aerobic Conditions

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
E. L. Shebs ◽  
M. J. Lukov ◽  
F. M. Giotto ◽  
E. S. Torres ◽  
A. S. De Mello
Keyword(s):  
Organic Acids ◽  
Fixed Effects ◽  
Antimicrobial Treatment ◽  
Aerobic Conditions ◽  
Bacterial Enumeration ◽  
Peptone Water ◽  
Industry Practice ◽  
Elevated Rate ◽  
Meat Samples

ObjectivesHigh event period (HEP) is a specific time length when processing facilities experience an elevated rate of STEC contamination. STEC contamination during beef fabrication is assessed by sampling trim combos usually using N60, N60 plus, or CSD cloth methods. However, beef primals produced during high event periods can also be affected and must be assessed. A common industry practice consists in reworking primals by removing them from vacuum sealed bags, treating with antimicrobials, repackaging, and then test for STEC. In this study, we evaluated the efficiency of bacteriophage and organic acid applications on contaminated beef kept under vacuum and aerobic conditions.Materials and MethodsAntimicrobials used in this study included: PhageGuard E (PGE, 108 PFU/ml, Bacteriophage solution from Micreos Food Safety BV), peroxyacetic acid (PAA, 400 PPM), and lactic acid (LA, 4.5% at 50°C). STEC O157:H7 strains included: ATCC® 35150 (stx1 and stx2 positive), ATCC® 43895 (stx1 and stx2 positive), ATCC® 43894 (stx1 and stx2 positive), and Micreos 128. Bacteriophage killing efficiency was determined for individual strains in vitro. Fresh rose meat (Cutaneous trunci) was cut into 100 cm2 and stored at 7°C. Meat samples (n = 160, 5 reps, 2 experimental units per rep) were randomly assigned to a 4×2×2 factorial whereas fixed effects were antimicrobial treatment (Control, PGE, PAA, and LA), packaging (V- vacuum and NV– aerobic), and lysing time (30 min and 6 h). Samples were inoculated with 500 ML of a STEC cocktail containing all 4 strains and after 30 min at 7°C under vacuum or wrapped in permeable film, samples were treated with 500 μL PGE, sterile buffered peptone water (BPW, Control), LA, or PAA. Samples were then re-vacuumed or re-wrapped with oxygen permeable film and kept either for 30 min or 6h at 7°C. After refrigeration, samples were swabbed and homogenized in 1mL of BPW. The swab content was serially diluted and spread-plated onto LB agar plates for bacterial enumeration. Data were analyzed using SAS as a completely randomized design.ResultsIn vitro killing efficiency was 98.3%, 96.7%, 97.2%, and 98.2% for Micreos 128, ATCC® 43894, ATCC® 43895, and ATCC® 35150 strains, respectively. When analyzing the effects of antimicrobials, packaging, and lysing time, a three-way interaction was observed (P = 0.035). Under aerobic conditions for 30 min, PGE reduced STEC in beef by approximately 1.4 log CFU/cm2 whereas organic acids reduced by 0.5 log. Similar results were observed when samples were kept for 6 h. Under vacuum conditions for 30 min, PGE significantly reduced STEC by 1 log, whereas no significant effects were observed when treating beef with PAA and LA. Under vacuum conditions for 6h, PGE significantly reduced STEC loads by 1.4 log, whereas LA reduced by 0.6 log and no differences were observed between control and PAA treatments.ConclusionBacteriophage applications on beef contaminated with STEC yielded the lowest counts when compared to PAA and LA. Although organic acids led to a significant decrease of STEC loads in beef kept under aerobic conditions, bacteriophage application led to the lowest counts. Similar to reworking and testing primals produced during a HEP, while under vacuum conditions, bacteriophage significantly reduced STEC loads whereas no or minimal effects of organic acids were observed.

scholarly journals Effects of Bacteriophage, Ultraviolet Light, and Organic Acid Applications on STEC O157:H7 and the “Big Six” in Beef Packaged Under Vacuum and Aerobic Conditions

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
E. L. Shebs ◽  
F. M. Giotto ◽  
M. J. Lukov ◽  
S. T. Laidler ◽  
A. S. De Mello
Keyword(s):  
Organic Acids ◽  
Ultraviolet Light ◽  
Antimicrobial Effect ◽  
Sodium Chlorite ◽  
Aerobic Conditions ◽  
Log Reduction ◽  
Bacterial Enumeration ◽  
Contrast Analysis ◽  
Antimicrobial Treatments ◽  
And Control

ObjectivesBeef primals produced during high event periods (HEP) can also be affected by STEC contamination requiring microbial assessment. Commonly, primals are retreated with antimicrobials after removal from vacuum bags, then repackaged and tested for STEC. In this study, we evaluated the efficiency of bacteriophage, ultraviolet light, and organic acids on contaminated beef kept under vacuum and aerobic conditions.Materials and MethodsThe effects of antimicrobial interventions Peroxyacetic acid (PAA, 400 PPM), Ultraviolet light (UV, 30 s at 2.5 ± 0.3 cm height), Acidified Sodium Chlorite (ASC, 1200 ppm), and bacteriophage (P, 7 MS phages at 108 PFU/ml) against STEC (O157:H7 and O145, O121, O111, O103, O45, O26) were evaluated on beef. Fresh m. cutaneous trunci was fabricated into 100 cm2 samples (n = 154), which were randomly assigned to 11 treatments including Control, P, UV, ASC, PAA, and combinations P+UV, P+PAA, P+ASC, UV+PAA, UV+ASC, PAA+ASC. Treatments were tested under vacuum and aerobic conditions. Samples were inoculated with a STEC cocktail comprised of 7 strains to yield 3 log CFU/cm2. Samples were vacuumed or overwrapped with oxygen permeable film. Samples were unpackaged and treated with buffered peptone water (BPW, Control) or individual or combined antimicrobial treatments prior to re-packaging. After 1 h at 7°C, samples were swabbed, homogenized in 1 mL of BPW, serially diluted and spread-plated for bacterial enumeration. Data was analyzed using SAS as a completely randomized design.ResultsOverall, treatments including MS phages significantly decreased STEC populations in beef under vacuum and aerobic conditions (P < 0.0001). Under vacuum, individual phage application, combinations between phage and UV, ASC, and PAA plus UV+ASC provided optimal STEC reduction on beef surface. Phage and PAA combination led to the lowest STEC load (1.49 log reduction). When analyzing contrasts, treatments with phage significantly decreased STEC loads when compared to other treatments (P < 0.0001) and control (P < 0.0001). STEC loads recovered from treatments without phage and control were statistically similar at P = 0.32. Under aerobic conditions, individual treatments UV and ASC and combinations including UV+PAA, and PAA+ASC were statistically similar to the control. Inclusion of phage in treatments gradually decreased STEC loads when combined with ASC, PAA, and UV. Phage and UV combination led to the lowest STEC load (1.46 log reduction). Contrast analysis showed that treatments with phage significantly decreased STEC loads when compared to other treatments (P < 0.0001) and control (P < 0.0001). STEC loads recovered from treatments without phage and control were statistically similar at P = 0.07.ConclusionIndividual or combined applications of MS phages on beef surface contaminated with STEC provided optimal antimicrobial effect under vacuum or aerobic conditions. Although organic acids and UV combinations did reduce STEC populations, treatments that included phage yielded the lowest STEC loads. Only phage interventions gave optimal reduction effects under vacuum conditions. Antimicrobial treatments based on individual phage cocktails and their combinations with ASC, UV, and PAA significantly reduce STEC when treating primals produced during HEP.

scholarly journals Importance and Antimicrobial Resistance of Mycoplasma bovis in Clinical Respiratory Disease in Feedlot Calves

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1470
Author(s):  
Ana García-Galán ◽  
Juan Seva ◽  
Ángel Gómez-Martín ◽  
Joaquín Ortega ◽  
Francisco Rodríguez ◽  
...  
Keyword(s):  
Respiratory Disease ◽  
Clinical Signs ◽  
Antimicrobial Treatment ◽  
Mycoplasma Bovis ◽  
Bacterial Disease ◽  
Feedlot Calves ◽  
Fixed Panel

Bovine respiratory disease (BRD) is an important viral and/or bacterial disease that mainly affects feedlot calves. The involvement of Mycoplasma bovis in BRD can lead to chronic pneumonia poorly responsive to antimicrobial treatment. Caseonecrotic bronchopneumonia is a pulmonary lesion typically associated with M. bovis. In Spain, M. bovis is widely distributed in the feedlots and circulating isolates are resistant to most antimicrobials in vitro. However, the role of this species in clinical respiratory disease of feedlot calves remains unknown. Furthermore, available data are relative to a fixed panel of antimicrobials commonly used to treat BRD, but not to the specific set of antimicrobials that have been used for treating each animal. This study examined 23 feedlot calves raised in southeast Spain (2016–2019) with clinical signs of respiratory disease unresponsive to treatment. The presence of M. bovis was investigated through bacteriology (culture and subsequent PCR), histopathology and immunohistochemistry. The pathogen was found in 86.9% (20/23) of the calves, mainly in the lungs (78.26%; 18/23). Immunohistochemistry revealed M. bovis antigens in 73.9% (17/23) of the calves in which caseonecrotic bronchopneumonia was the most frequent lesion (16/17). Minimum inhibitory concentration assays confirmed the resistance of a selection of 12 isolates to most of the antimicrobials specifically used for treating the animals in vivo. These results stress the importance of M. bovis in the BRD affecting feedlot calves in Spain.

Killing of Chinese hamster cells in vitro by heating under hypoxic or aerobic conditions

1974 ◽  
Vol 10 (10) ◽  
pp. 691-693 ◽  
Author(s):  
Leo E. Gerweck ◽  
Edward L. Gillette ◽  
William C. Dewey
Keyword(s):  
Chinese Hamster ◽  
Aerobic Conditions ◽  
Chinese Hamster Cells

scholarly journals EXPERIMENTS ON THE SURVIVAL OF THE FEBRILE HERPETIC AND ALLIED VIRUSES IN VITRO

1924 ◽  
Vol 39 (4) ◽  
pp. 533-542 ◽  
Author(s):  
James E. McCartney
Keyword(s):  
Brain Tissue ◽  
Secondary Infection ◽  
The Body ◽  
Herpes Viruses ◽  
Encephalitis Lethargica ◽  
Aerobic Conditions ◽  
Maximum Period ◽  
Suitable Technique ◽  
The Brain

These studies fail to confirm the statements previously made that microorganisms of the class of the globoid bodies of poliomyelitis may be cultivated in the Smith-Noguchi medium from the so called virus of encephalitis lethargica. They show equally that the herpes virus does not multiply in this medium. The experiments indicate, moreover, that the medium is unfavorable to the survival of the virus, while ordinary broth under aerobic conditions is more favorable for maintaining the activity of both the encephalitic and the herpes viruses. Probably no multiplication of either takes place in the latter medium but merely a survival, and for a maximum period of 6 days in the broth itself, and 12 days in the fragment of brain tissue immersed in the broth. Finally, it has been shown that with a suitable technique the viruses can be passed from the brain of one rabbit to that of another through a long series without contamination with cocci or other common bacterial forms. Hence we regard all reports of the finding of ordinary bacteria in the brain of cases of epidemic or lethargic encephalitis as instances of mixed or secondary infection arising during life, or examples of postmortem invasion of the body, or of faulty technique at the autopsy.

Effect of Thymus ciliatus oil-based disinfectant solutions against bio-films formed by Bacillus cereus strains isolated from pasteurized-milk processing lines in Algeria

2018 ◽  
Vol 8 (1) ◽  
pp. 01-12
Author(s):  
Amina Kalai ◽  
Fadila Malek ◽  
Leila Bousmaha-Marroki
Keyword(s):  
Essential Oil ◽  
Organic Acids ◽  
Bacillus Cereus ◽  
Biofilm Formation ◽  
Chemical Cleaning ◽  
Pasteurized Milk ◽  
Thyme Oil ◽  
Milk Processing ◽  
Planktonic Growth

Bacillus cereus is a foodborne pathogen that often persists in dairy environments and is associated with food poisoning and spoilage. This spore-forming bacterium has a high propensity to develop biofilms onto dairy processing equipment and resists to chemical cleaning and disinfecting. This study deals with the in vitro application of thyme oil-based sanitizer solutions against biofilms formed by B. cereus genotypes which persist in pasteurized-milk processing lines. The effect of Thymus ciliatus essential oil on B. cereus planktonic cells and biofilms was assessed. The oil was tested alone and in combination with organic acids or industrial cleaning agents, in order to improve the removal of B. cereus recurrent genotypes. Minimal inhibitory concentrations of planktonic growth (MICs), biofilm formation (MBIC) and biofilm eradication (MBEC) of oil and organic acids were evaluated by microdilution assays. Thyme oil was more effective than organic acids against B. cereus planktonic growth, biofilm formation and established bio-films. High values of MICs were obtained for the three organic acids tested (3.5-4.5%) in comparison with those of essential oil (0.082-0.088%). The combination of oil with other antimicrobials as acetic acid, NaOH or HNO3 improves their effectiveness against B. cereus biofilms. These oil-based sanitizer solutions allow complete B. cereus biofilm eradication and should be an attractive candidate for the control and removal of biofilms in the dairy envi-ronment.

The in vitro efficacy of neutral electrolysed water and povidone-iodine against CRS-associated biofilms

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
C.A. Lux ◽  
K. Biswas ◽  
M.W. Taylor ◽  
R.G. Douglas
Keyword(s):  
Inhibitory Concentration ◽  
Povidone Iodine ◽  
Minimum Bactericidal Concentration ◽  
Treatment Options ◽  
Antimicrobial Treatment ◽  
Biofilm Reactor ◽  
Bacterial Biofilms ◽  
Antibiofilm Activity

Background: Despite best medical and surgical practice, some cases of chronic rhinosinusitis (CRS) can remain recalcitrant. Bacterial biofilms have been associated with the recalcitrance of sinonasal inflammation. Biofilms are highly resistant to commonly prescribed antibiotics. Accordingly, more effective antimicrobial treatment options are needed to treat refractory CRS. The aim of this study was to determine the in vitro efficacy of neutral electrolysed water (NEW) and povidone-iodine (PVI) against CRS-associated Staphylococcus aureus biofilms. Methods: Mature S. aureus biofilms were grown in a Centre for Disease Control (CDC) biofilm reactor. The antimicrobial activity of NEW, PVI and doxycycline was determined for both planktonic and biofilm cultures of a clinical S. aureus isolate using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) assays. Results: MICs and MBCs were determined for all antimicrobials. MBC values were similar to MICs for both antiseptics, but doxycycline MBCs were significantly higher than the associated MICs. Biofilms were highly resistant to NEW and doxycycline. The MBEC for doxycycline was between 500 and 1000 µg/mL. NEW was ineffective against biofilms and no MBEC could be determined. In contrast, a concentration of 10% of the commercial PVI solution (10 mg/mL PVI) led to effective eradication of mature biofilms. Conclusion: In this study, only PVI showed promising antibiofilm activity at physiological concentrations. The in vivo efficacy of PVI warrants further investigation of its potential as a treatment for recalcitrant CRS.

METABOLISM OF RAM TESTICULAR SPERMATOZOA IN THE PRESENCE OF TESTOSTERONE AND RELATED STEROIDS

1970 ◽  
Vol 65 (3) ◽  
pp. 565-576 ◽  
Author(s):  
J. K. Voglmayr ◽  
R. N. Murdoch ◽  
I. G. White
Keyword(s):  
Aerobic Glycolysis ◽  
Rete Testis ◽  
Glycolytic Metabolism ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Testicular Spermatozoa ◽  
Almost All ◽  
Oxidation Of Glucose

ABSTRACT The effects of testosterone* and related steroids on the oxidative and glycolytic metabolism of freshly collected ram testicular spermatozoa and of spermatozoa stored under air in rete testis fluid for 3 days at 3°C have been studied. When freshly collected testicular spermatozoa were incubated with glucose under aerobic conditions only a small proportion of the utilized glucose could be accounted for as lactate. The addition of a number of steroids, including testosterone, androstanedione, 5β-androstanedione, androsterone, epiandrosterone and 5β-androsterone, greatly increased aerobic glycolysis, the oxidation of the substrate and the proportion of the utilized substrate converted to lactic acid. After 3 days storage at 3°C, testicular spermatozoa respired at a greater rate than spermatozoa freshly collected from the testes. Although the stimulating effect of steroids on aerobic glycolysis increased after storage, they depressed rather than stimulated the oxidation of glucose by stored testicular spermatozoa. With the exception of androstanedione, which slightly stimulated glycolysis, storage of testicular spermatozoa for 3 days in the presence of steroids did not significantly influence their subsequent metabolism when washed free of the steroids. Both freshly collected and stored ram testicular spermatozoa displayed a marked Pasteur effect, and utilized more glucose and produced more lactate under anaerobic than under aerobic conditions. In the absence of oxygen the steroids did not stimulate glycolysis to any extent. However, epiandrosterone depressed the glycolysis of freshly collected spermatozoa under anaerobic conditions and after storage, 5β-androsterone had a similar effect. Androstanedione, 5β-androstanedione, epiandrosterone and 5β-androsterone were the most effective steroids in altering the metabolism of testicular spermatozoa and, under almost all conditions of incubation, depressed the synthesis of amino acids from glucose. The results suggest that the effects of testosterone and related steroids in vitro may depend on the age of the spermatozoa after their release from the Sertoli cells; the steroid effects may have important consequences in vivo in relation to sperm maturation.

scholarly journals Effects of some organic acids and salts on microbial fermentation in the digestive tract of piglets estimated using an in vitro gas production technique

2008 ◽  
Vol 14 (4) ◽  
pp. 311 ◽  
Author(s):  
K. PARTANEN ◽  
T. JALAVA
Keyword(s):  
Organic Acids ◽  
Formic Acid ◽  
Digestive Tract ◽  
Sodium Benzoate ◽  
Gas Production ◽  
Control Treatment ◽  
Potassium Sorbate ◽  
Microbial Fermentation ◽  
Calcium Formate

An in vitro gas production technique was used to screen different organic acids (formic, propionic, lactic, citric, and fumaric acid), organic salts (calcium formate, potassium sorbate, and sodium benzoate), and inorganic phosphoric acid for their ability to modulate microbial fermentation in the digestive tract of piglets. For the incubation, 40 ml of culture medium (53% buffer, 45% frozen ileal digesta, and 2% fresh faeces) was dispensed in vessels containing 5 ml of buffer, 0.5 g of feed, and 20 ìl of liquid or 20 mg of solid acidifiers. Gas production was measured every 15 min during the 24 h incubation at 39°C, and a Gompertz bacterial growth model was applied to the gas production data. Formic acid was the only acid that reduced the maximum rate of gas production (ìm) compared to that in the control treatment (P < 0.05). The ìm was slower in vessels with formic acid than in those with calcium formate, citric acid, and potassium sorbate (P < 0.05) Calcium formate increased the ìm compared to the control treatment (P < 0.05). The maximum volume of gas produced and the lag time did not differ between different acidifiers (P > 0.05). When investigating formic-acid-based mixtures that contained 1–5% of potassium sorbate and/or sodium benzoate, the estimated parameters for the Gompertz growth model did not differ from those for treatments with plain formic acid (P > 0.05). However, concentrations of total volatile fatty acids, acetic acid, propionic acid, and n-butyric acid were reduced by all the mixtures (P < 0.05), but not by plain formic acid (P > 0.05). In conclusion, organic acids and salts were found to differ in their ability to modulate microbial fermentation in the digestive tract of piglets. Mixing formic acid with potassium sorbate or sodium benzoate changed fermentation patterns, and the possibility to use them to enhance the antimicrobial effect of formic acid should be investigated further in vivo.;

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