Effect of Treatment Conditions on Nisin Inactivation of Gram-negative Bacteria

1992 ◽  
Vol 55 (10) ◽  
pp. 763-766 ◽  
Author(s):  
KELLY A. STEVENS ◽  
BRIAN W. SHELDON ◽  
N. ARLENE KLAPES ◽  
TODD R. KLAENHAMMER
Keyword(s):  
Citric Acid ◽  
Incubation Temperature ◽  
Chelating Agent ◽  
Gram Negative Bacteria ◽  
Citric Acid Monohydrate ◽  
Gram Negative ◽  
Treatment Conditions ◽  
Effect Of Treatment ◽  
Gram Negative Organisms ◽  
Sodium Phosphate Dibasic

A method using nisin and a chelating agent to inactivate Salmonella species and other gram-negative bacteria has been developed. The objective of this study was to determine the effect of treatment conditions on the application of this method. Ten gram-negative organisms were used in this study, including six Salmonella species commonly associated with foodborne illness. Organisms were selected on the basis of sensitivity to nisin and a chelating agent. The following parameters were examined: (a) chelating agent, (b) nisin concentration, (c) incubation temperature, and (d) protein interference. Chelating agents included EDTA, ethylenebis (oxyethylene-nitrilo) tetraacetic acid, citric acid monohydrate, and sodium phosphate dibasic. The most effective treatment consisted of 50 to 100 μg/ml nisin applied in combination with 20 mM EDTA or citric acid monohydrate at a temperature range of 30 to 42°C. All of the chelators examined exhibited some inhibitory activity. The addition of bovine serum albumin to the treatments containing nisin and EDTA did not result in a significant decrease in inhibitory action.

Effectiveness of Trisodium Phosphate, Acidified Sodium Chlorite, Citric Acid, and Peroxyacids against Pathogenic Bacteria on Poultry during Refrigerated Storage

2007 ◽  
Vol 70 (9) ◽  
pp. 2063-2071 ◽  
Author(s):  
ELENA del RÍO ◽  
REBECA MURIENTE ◽  
MIGUEL PRIETO ◽  
CARLOS ALONSO-CALLEJA ◽  
ROSA CAPITA
Keyword(s):  
Citric Acid ◽  
Salmonella Enteritidis ◽  
Pathogenic Bacteria ◽  
Trisodium Phosphate ◽  
Sodium Chlorite ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Microbial Group ◽  
And Control

The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 ± 1°C. All chemical solutions reduced microbial populations (P < 0.001) as compared with the control (untreated) samples. Similar bacterial loads (P > 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of storage, the pH of legs treated with TSP remained higher and that of legs treated with CA remained lower than normal.

Fusobacterium nucleatum, the first Gram-negative bacterium demonstrated to produce polyglutamate

2009 ◽  
Vol 55 (5) ◽  
pp. 627-632 ◽  
Author(s):  
Thomas Candela ◽  
Marie Moya ◽  
Michel Haustant ◽  
Agnès Fouet
Keyword(s):  
In Silico Analysis ◽  
Fusobacterium Nucleatum ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
The Third ◽  
Gram Negative Organisms ◽  
First Time

Poly-γ-glutamate has been described in many Gram-positive organisms. When anchored to the surface, it is a capsule and as such a virulence factor. Based on sequence similarities, few Gram-negative organisms have been suggested to synthesize poly-γ-glutamate. For the first time, a Gram-negative bacterium, Fusobacterium nucleatum , is shown to produce and secrete poly-γ-glutamate. Putative poly-γ-glutamate-synthesizing genes from Gram-negative organisms have been compared with their Gram-positive homologs by in silico analysis, i.e., gene sequence and phylogenetic analysis. Clusters of three instead of four genes were highlighted by our screen. The products of the first two genes display similarity with their Gram-positive equivalents, yet the sequences from the Gram-negative organisms can be distinguished from those of the Gram-positives. Interestingly, the sequence of the predicted product of the third gene is conserved among Gram-negative bacteria but displays no similarity to that of either the third or fourth gene of the Gram-positive operons. It is suggested that, like for Gram-positive bacteria, poly-γ-glutamate has a role in virulence for pathogens and one in survival for other Gram-negative bacteria.

Gram-Negative Diabetic Foot Osteomyelitis

2013 ◽  
Vol 12 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Javier Aragón-Sánchez ◽  
Benjamin A. Lipsky ◽  
Jose L. Lázaro-Martínez
Keyword(s):  
Blood Cell ◽  
Glycated Hemoglobin ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Cell Counts ◽  
Blood Cell Counts ◽  
White Blood Cell Counts ◽  
Gram Negative Organisms ◽  
Diabetic Foot Osteomyelitis

Osteomyelitis frequently complicates infections in the feet of patients with diabetes. Gram-positive cocci, especially Staphylococcus aureus, are the most commonly isolated pathogens, but gram-negative bacteria also cause some cases of diabetic foot osteomyelitis (DFO). These gram-negatives require different antibiotic regimens than those commonly directed at gram-positives. There are, however, few data on factors related to their presence and how they influence the clinical picture. We conducted a retrospective study to determine the variables associated with the isolation of gram-negative bacteria from bone samples in cases of DFO and the clinical presentation of these infections. Among 341 cases of DFO, 150 had a gram-negative isolate (alone or combined with a gram-positive isolate) comprising 44.0% of all patients and 50.8% of those with a positive bone culture. Compared with gram-positive infections, wounds with gram-negative organisms more often had a fetid odor, necrotic tissue, signs of soft tissue infection accompanying osteomyelitis, and clinically severe infection. By multivariate analysis, the predictive variables related to an increased likelihood of isolating gram-negatives from bone samples were glycated hemoglobin <7% (odds ratio [OR] = 2.0, 95% confidence interval [CI] = 1.1-3.5) and a wound caused by traumatic injury (OR = 2.0, 95% CI = 1.0-3.9). Overall, patients whose bone samples contained gram-negatives had a statistically significantly higher prevalence of leukocytosis and higher white blood cell counts than those without gram-negatives. In conclusion, gram-negative organisms were isolated in nearly half of our cases of DFO and were associated with more severe infections, higher white blood cell counts, lower glycated hemoglobin levels, and wounds of traumatic etiology.

Bacteriological Sampling of Telephones and Other Hospital Staff Hand-Contact Objects

1984 ◽  
Vol 5 (11) ◽  
pp. 533-535 ◽  
Author(s):  
Karen M. Rafferty ◽  
Stephen J. Pancoast
Keyword(s):  
General Hospital ◽  
Acute Care ◽  
Staff Member ◽  
Pathogenic Bacteria ◽  
Bacterial Contamination ◽  
Hospital Staff ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Gram Negative Organisms ◽  
Hand Contact

AbstractIn an acute-care general hospital, 114 telephones, intercoms, dictaphones, and bedpan flusher handles were sampled in patient-care areas for type of bacterial contamination. Nine of these (7%) demonstrated potentially pathogenic bacteria including Klebsiella, Enterobacter, Pseudomonas and Aeromonas. Inanimate, environmental, staff hand-contact objects were only lightly contaminated, did not represent a significant reservoir of gram-negative organisms, and therefore, would be unlikely to be a vehicle of transmission of gram-negative bacteria from the hands of one staff member to another under routine circumstances. Surveillance and disinfection of telephones and related hand-contact items in the hospital appear unnecessary.

Confirmation and Identification of Salmonella spp., Cronobacter spp., and Other Gram-Negative Organisms by the Bruker MALDI Biotyper Method: Collaborative Study, First Action 2017.09

2018 ◽  
Vol 101 (5) ◽  
pp. 1593-1609 ◽  
Author(s):  
Benjamin Bastin ◽  
Patrick Bird ◽  
M Joseph Benzinger ◽  
Erin Crowley ◽  
James Agin ◽  
...  
Keyword(s):  
United States ◽  
Collaborative Study ◽  
The United States ◽  
Gram Negative Bacteria ◽  
Salmonella Spp ◽  
Gram Negative ◽  
Genus Level ◽  
Alternative Method ◽  
Maldi Biotyper ◽  
Gram Negative Organisms

Abstract The Bruker MALDI Biotyper® method utilizes matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS for the rapid and accurate identification and confirmation of Gram-negative bacteria from select media types. The alternative method was evaluated using nonselective and selective agars to identify Cronobacter spp., Salmonella spp., and select Gram-negative bacteria. Results obtained by the Bruker MALDI Biotyper were compared to the traditional biochemical methods as prescribed in the appropriate reference methods. Two collaborative studies were organized, one in the United States focusing on Cronobacter spp. and other Gram-negative bacteria, and one in Europe focusing on Salmonella spp. and other Gram-negative bacteria. Fourteen collaborators from seven laboratories located within the United States participated in the first collaborative study for Cronobacter spp. Fifteen collaborators from 15 service laboratories located within Europe participated in the second collaborative study for Salmonella spp. For each target organism (either Salmonella spp. or Cronobacter spp.), a total of 24 blind-coded isolates were evaluated. In each set of 24 organisms, there were 16 inclusivity organisms (Cronobacter spp. or Salmonella spp.) and 8 exclusivity organisms (closely related non-Cronobacter spp. and non-Salmonella spp. Gram-negative organisms). After testing was completed, the total percentage of correct identifications from each agar type for each strain was determined at a percentage of 100.0% to the genus level for the Cronobacter study and a percentage of 100.0% to the genus level for the Salmonella study. For both non-Cronobacter and non-Salmonella organisms, a percentage of 100.0% was correctly identified. The results indicated that the alternative method produced equivalent results when compared to the confirmatory procedures specified by each reference method.

Bactericidal Properties of Ozone and Its Potential Application as a Terminal Disinfectant

2000 ◽  
Vol 63 (8) ◽  
pp. 1100-1106 ◽  
Author(s):  
GINNY MOORE ◽  
CHRIS GRIFFITH ◽  
ADRIAN PETERS
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Food Industry ◽  
Yeast Cells ◽  
Ozone Exposure ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Uht Milk ◽  
Bactericidal Properties ◽  
Gram Negative Organisms

The efficacy of ozone as a terminal disinfectant was evaluated under laboratory conditions. Different microorganisms of importance to the food industry were inoculated onto stainless steel squares and incubated at various temperatures and relative humidities for up to 4 h. Survival of microorganisms from these controls was compared with identically incubated squares exposed to ozone. Exposure of the contaminated surfaces to ozone (2 ppm for 4 h) resulted in a reduction in microbial viability that ranged, depending on organism type, from 7.56 to 2.41 log values. For all the microorganisms tested, this loss in viability was significantly greater (P &lt; 0.05) than that observed in the absence of ozone. Gram-negative bacteria were more sensitive to ozone than gram-positive organisms; bacteria were more sensitive than the yeast strain tested. Exposure to ozone (2 ppm for 4 h) in the presence of ultra-high temperature (UHT) milk resulted in a reduction in bacterial viability that ranged from 5.64 to 1.65 log values. In most cases, this reduction was significantly less (P &lt; 0.05) than that achieved in the absence of organic material, although still significantly greater (P &lt; 0.05) than that observed in the absence of ozone. The presence of a meat-based broth reduced the effectiveness of ozone to a greater extent, although the number of surviving gram-negative organisms was still significantly less (P &lt; 0.05) than in the absence of ozone. Less than 1 log unit of yeast cells was destroyed when exposed to ozone in the presence of UHT milk or meat-based broth. Results of this investigation suggest that if applied after adequate cleaning ozone could be used as an effective disinfectant.

scholarly journals Phenotypic characterization of carbapenem non-susceptible gram-negative bacilli isolated from clinical specimens

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0256556
Author(s):  
Abera Abdeta ◽  
Adane Bitew ◽  
Surafel Fentaw ◽  
Estifanos Tsige ◽  
Dawit Assefa ◽  
...  
Keyword(s):  
Public Health ◽  
Prevention And Control ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Extensively Drug Resistant ◽  
Gram Negative Organisms ◽  
And Control ◽  
Public Health Institute

Background Multidrug resistant, extremely drug-resistant, pan-drug resistant, carbapenem-resistant, and carbapenemase-producing gram-negative bacteria are becoming more common in health care settings and are posing a growing threat to public health. Objective The study was aimed to detect and phenotypically characterize carbapenem no- susceptible gram-negative bacilli at the Ethiopian Public Health Institute. Materials and methods A prospective cross-sectional study was conducted from June 30, 2019, to May 30, 2020, at the national reference laboratory of the Ethiopian Public Health Institute. Clinical samples were collected, inoculated, and incubated for each sample in accordance with standard protocol. Antimicrobial susceptibility testing was conducted using Kirby-Bauer disk diffusion method. Identification was done using the traditional biochemical method. Multidrug-resistant and extensively drug-resistant isolates were classified using a standardized definition established by the European Centre for Disease Prevention and Control and the United States Centers for Disease Prevention and Control. Gram-negative organisms with reduced susceptibility to carbapenem antibiotics were considered candidate carbapenemase producers and subjected to modified carbapenem inactivation and simplified carbapenem inactivation methods. Meropenem with EDTA was used to differentiate metallo-β-lactamase (MBL) from serine carbapenemase. Meropenem (MRP)/meropenem + phenylboronic acid (MBO) were used to differentiate Klebsiella pneumoniae carbapenemase (KPC) from other serine carbapenemase producing gram-negative organisms. Results A total of 1,337 clinical specimens were analyzed, of which 429 gram-negative bacterial isolates were recovered. Out of 429 isolates, 319, 74, and 36 were Enterobacterales, Acinetobacter species, and Pseudomonas aeruginosa respectively. In our study, the prevalence of multidrug-resistant, extensively drug-resistant, carbapenemase-producing, and carbapenem nonsusceptible gram-negative bacilli were 45.2%, 7.7%, 5.4%, and 15.4% respectively. Out of 429 isolates, 66 demonstrated reduced susceptibility to the antibiotics meropenem and imipenem. These isolates were tested for carbapenemase production of which 34.8% (23/66) were carbapenemase producers. Out of 23 carbapenemase positive gram-negative bacteria, ten (10) and thirteen (13) were metallo-beta-lactamase and serine carbapenemase respectively. Three of 13 serine carbapenemase positive organisms were Klebsiella pneumoniae carbapenemase. Conclusion This study revealed an alarming level of antimicrobial resistance (AMR), with a high prevalence of multidrug-resistant (MDR) and extremely drug-resistant, carbapenemase-producing gram-negative bacteria, particularly among intensive care unit patients at the health facility level. These findings point to a scenario in which clinical management of infected patients becomes increasingly difficult and necessitates the use of “last-resort” antimicrobials likely exacerbating the magnitude of the global AMR crisis. This mandates robust AMR monitoring and an infection prevention and control program.

Infections caused by Gram-negative bacteria

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
Causes Of Disease ◽  
Gram Negative Organisms ◽  
The Tropics

This chapter consists of short notes, diagrams, and tables to summarize Gram-negative organisms that are significant causes of disease in the tropics and subtropics. This includes Escherichia coli, Shigella, and Salmonella species (including typhoid and paratyphoid), Brucella, melioid, Campylobacter, and meningococci. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention.

Antimicrobial Resistance in the Intensive Care Unit

2016 ◽  
Vol 32 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Shawn H. MacVane
Keyword(s):  
Intensive Care ◽  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Treatment Options ◽  
Hospital Costs ◽  
High Morbidity ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Gram Negative Organisms

Bacterial infections are a frequent cause of hospitalization, and nosocomial infections are an increasingly common condition, particularly within the acute/critical care setting. Infection control practices and new antimicrobial development have primarily focused on gram-positive bacteria; however, in recent years, the incidence of infections caused by gram-negative bacteria has risen considerably in intensive care units. Infections caused by multidrug-resistant (MDR) gram-negative organisms are associated with high morbidity and mortality, with significant direct and indirect costs resulting from prolonged hospitalizations due to antibiotic treatment failures. Of particular concern is the increasing prevalence of antimicrobial resistance to β-lactam antibiotics (including carbapenems) among Pseudomonas aeruginosa and Acinetobacter baumannii and, recently, among pathogens of the Enterobacteriaceae family. Treatment options for infections caused by these pathogens are limited. Antimicrobial stewardship programs focus on optimizing the appropriate use of currently available antimicrobial agents with the goals of improving outcomes for patients with infections caused by MDR gram-negative organisms, slowing the progression of antimicrobial resistance, and reducing hospital costs. Newly approved treatment options are available, such as β-lactam/β-lactamase inhibitor combinations, which significantly extend the armamentarium against MDR gram-negative bacteria.

DISCUSSION FOLLOWING PAPER BY DR. LIGHT IN WHICH EVIDENCE WAS PRESENTED THAT HEXACLOROPHENE IS NOT EFFECTIVE

PEDIATRICS ◽  
1973 ◽  
Vol 51 (2) ◽  
pp. 354-356
Keyword(s):  
San Francisco ◽  
Inverse Relationship ◽  
Newborn Infants ◽  
Gram Negative Bacteria ◽  
Inverse Relation ◽  
Infection Rates ◽  
Gram Negative ◽  
Intensive Intervention ◽  
Gram Negative Organisms ◽  
Colonization Rates

Dr. Shinefield: Stated that at Cornell in the late 50's serious newborn infections occurred with 80-81 staph. The technics employed at that time affected neither colonization nor disease. No special attention was given to the umbilical area. In the early 1960's the colonization rate with 80-81 was about 40%, but the organism began to disappear spontaneously. At this point, with hexachlorophene data available, it was decided that hexachlorophene would not be used and the standard technics were employed. The nursery had no infections for the next 2 years. In San Francisco he has studied 17,000 newborn infants who as a result of the Kaiser plan are well followed. He found 40 to 80% colonization rates and independently of the technics used; 4 per 1,000 babies developed pustules but no serious staph infections. He felt that colonization by itself may not be harmful unless one is dealing with "hot" strains. He believes that if ordinary aseptic technics can change colonization rates from 40 to 80%, their average rates, down to 5 to 10%, and change infection rates from 4 to 1 per 1,000, one should be cautious about additional measures. He believes that a 4/1,000 pustule rate in a nonepidemic period is not alarming and that intensive intervention may give rise to difficulty. He asked Dr. Light about the inverse relation between staph and gram-negative organisms raising the question as to whether it is staph or nonpathogenic micrococci which holds down gram-negative bacteria. Dr. Light: Replied that studies showed the inverse relationship between coagulase-positive staph and pseudomonas.

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