scholarly journals 045 ANTIBIOTIC SUSCEPTIBILITY OF PLANT-ASSOCIATED BACTERIA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 434c-434 ◽  
Author(s):  
Patricia M. Buckley ◽  
Barbara M. Reed
Keyword(s):  
Bacterial Growth ◽  
Infected Plant ◽  
Basic Information ◽  
Ph Change ◽  
Gram Positive ◽  
Associated Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antibiotic Susceptibilities ◽  
Microbial Contaminants

Most bacteria isolated from persistently contaminated micropropagated mint plants were Gram-negative rods identified as xanthomonads, pseudomonads, and agrobacteria based on their cultural characteristics. A few Gram-positive, non-sporeforming bacteria were also found. Inhibition of bacterial growth by gentamicin and streptomycin was greater at pH 6.5 and pH 7.5 than at pH 5.5. Inhibition by rifampicin and Timentin was less affected by pH change. Pseudomonads were uniformly resistant to Timentin at all pH's and at levels up to 1000 μg/ml. Streptomycin at 500 μg/ml was bactericidal for the pseudomonads and Gram-positive bacteria while 1000 μg/ml was required to kill xanthomonads and agrobacteria. Minimal bactericidal concentrations for gentamicin varied widely, even within groups, and ranged from 10 μg/ml to >80 μg/ml for agrobacteria. These results emphasize a need to acquire basic information about the identities and antibiotic susceptibilities of microbial contaminants before attempting treatment of infected plant cultures.

scholarly journals Pattern of antibiotic resistance of various strains of bacteria causing acute tonsillitis

2021 ◽  
Vol 7 (6) ◽  
pp. 994
Author(s):  
N. Jyothsna ◽  
A. Ramya ◽  
K. Abhilash ◽  
Bathsa Liza Johnson
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Growth ◽  
Bacterial Strain ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Acute Tonsillitis ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antibiotic Drugs ◽  
Significant Difference

<p class="abstract"><strong>Background:</strong> Our study was done to determine the pattern of antibiotic resistance of various strains of bacteria causing acute tonsillitis.</p><p class="abstract"><strong>Methods:</strong> the study was a randomized cross sectional study. Patients matching the inclusion criteria were included. Duration of study was 6 months.</p><p class="abstract"><strong>Results:</strong> Out of 120 cases, 46 cases showed no bacterial growth (NBG) and 74 cases showed bacterial growth. 42 cases were gram-negative bacterial strain and 32 cases were positive bacterial strain out of 72 bacterial grown cases. A list of 25 antibiotic drugs in gram-negative and 31 drugs in gram-positive strain, their sensitivity and resistance were taken and noted. Among gram-negative bacteria imipenem (71.4%) showed highest sensitivity. Highest antibiotic resistance was seen in ampicillin (85.71%). Least sensitivity is observed in clindamycin, amoxicillin+clavulanic acid with 2.38%. Among gram-positive bacteria, highest sensitivity was noted in cefotaxime (75%). Highest antibiotic resistance was seen in cotrimoxazole (46.8%). Least sensitivity is observed in netilmicin, sulbactam with 3.12%.</p><p class="abstract"><strong>Conclusions:</strong> The number of drugs resistant to the gram-positive bacteria are lesser than number of drugs sensitive, which showed significant difference (p&lt;0.05). Significant difference of antibiotic drugs was not found in gram-negative bacteria. Our study findings helped in appropriate and guarded use of the antibiotic drugs in acute tonsillitis, minimizing the exposure of individuals to antibiotic resistance by choosing an appropriate sensitive drug, therefore improving the quality of therapy.</p>

scholarly journals Microbiological Isolates and Antibiotic Susceptibilities in Cases of Posttraumatic Endophthalmitis: A 15-Year Review

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Chunhong Liu ◽  
Jian Ji ◽  
Zhujian Wang ◽  
Huiwen Chen ◽  
Wenjun Cao ◽  
...  
Keyword(s):  
Antibiotic Sensitivity ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Fungal Isolates ◽  
Antibiotic Susceptibilities ◽  
Chi Squared ◽  
Posttraumatic Endophthalmitis ◽  
Over Time

Purpose. The objective of this study was to evaluate the microbiological spectrum and antibiotic susceptibilities of isolates in posttraumatic endophthalmitis over a 15-year period. Methods. A retrospective study of 3,163 posttraumatic endophthalmitis cases was conducted between July 2004 and July 2019. The outcome measures included the microbiological spectrum and antibiotic susceptibilities. Chi-squared tests were conducted to detect trends in changes in antibiotic sensitivity over the 15-year period. P values of <0.05 were considered statistically significant. Results. Of the 3,163 cases of posttraumatic endophthalmitis, 1,003 culture-positive isolates were identified. Among these, there were 848 (84.5%) Gram-positive isolates, 109 (10.9%) Gram-negative isolates, and 46 (4.6%) fungal isolates. The most common isolates were Staphylococcal species. There was a significant increase in the percentage of fungal isolates over the 15-year period (P=0.02). Gram-positive organisms showed the greatest level of susceptibility to vancomycin (99.6%). The susceptibilities of the 109 Gram-negative isolated organisms were as follows: levofloxacin (95.8%), meropenem (95.7%), ciprofloxacin (93.5%), tobramycin (90.8%), imipenem (88.9%), trimethoprim-sulfamethoxazole (TMP-SMX) (87.7%), ertapenem (80%), and ceftazidime (79.1%). The susceptibility of Gram-positive organisms to several antibiotics, including levofloxacin (P=0.004), ciprofloxacin (P<0.001), and chloramphenicol (P=0.001) decreased over time, whereas the susceptibility to TMP-SMX increased over time (P<0.001). The susceptibility of Gram-negative bacilli to ceftazidime decreased over time (P=0.03). Conclusions. Over the 15-year study period, most isolates were Gram-positive cocci, especially coagulase-negative staphylococci (CNS). Vancomycin seemed to be the most effective antibiotic for Gram-positive bacteria. Gram-negative bacteria appeared to be most susceptible to fluoroquinolones. A number of antibiotics showed an increasing trend of microbial resistance.

scholarly journals Frequency Electromagnetic field effects on Gram-Positive and Gram-Negative Bacteria

2019 ◽  
Author(s):  
Mohamad Reza Bayatiani ◽  
fatemeh seif ◽  
mohamad Arjomandzadegan ◽  
alireza moradabadi ◽  
arash parvin
Keyword(s):  
Electromagnetic Field ◽  
Bacterial Growth ◽  
Electromagnetic Waves ◽  
Control Group ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Living Organisms ◽  
Escherichia Coli Bacteria ◽  
And Control

Abstract Abstract Objective: The effects of electromagnetic waves on the growth of living organisms and the determination of the threshold of these radiations have remained elusive. Therefore, in this research, we have investigated the growth rate of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria that had been exposed to the different frequencies of electromagnetic fields. Results: The more frequency increased the slower bacteria grew; however, in gram-positive bacteria such as S. aureus, this effect was seen less. The effect of the 1mT electromagnetic field in the growth of S. aureus was significant between the two groups, nonetheless, in the 2mT electromagnetic field, the effect was not significant between the two groups at different frequencies. Noteworthy, no significant change was observed by increasing the frequency in S. aureus exposed bacteria in comparison to the control group. The study of bacterial growth in terms of frequency in both case and control groups showed an increasing trend. Increasing the frequency from 50 Hz to 150Hz, significantly, enhanced the rate of bacterial growth. On the whole, the magnetic field had an increment effect on the growth of bacteria; in fact, this effect was greater on the gram-negative than on the gram-positive bacteria.

The Evolution, Ecology, and Mechanisms of Infection by Gram-Positive, Plant-Associated Bacteria

2019 ◽  
Vol 57 (1) ◽  
pp. 341-365 ◽  
Author(s):  
Shree P. Thapa ◽  
Edward W. Davis ◽  
Qingyang Lyu ◽  
Alexandra J. Weisberg ◽  
Danielle M. Stevens ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Future Research ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Research Directions ◽  
Associated Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Causative Agents ◽  
Future Research Directions

Gram-positive bacteria are prominent members of plant-associated microbial communities. Although many are hypothesized to be beneficial, some are causative agents of economically important diseases of crop plants. Because the features of Gram-positive bacteria are fundamentally different relative to those of Gram-negative bacteria, the evolution and ecology as well as the mechanisms used to colonize and infect plants also differ. Here, we discuss recent advances in our understanding of Gram-positive, plant-associated bacteria and provide a framework for future research directions on these important plant symbionts.

scholarly journals Effect of N-acetylcysteine on antibiotic activity and bacterial growth in vitro

1977 ◽  
Vol 5 (1) ◽  
pp. 58-61 ◽  
Author(s):  
M F Parry ◽  
H C Neu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Antibiotic Activity ◽  
Clinical Use ◽  
Microbiology Laboratory ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

The antibiotic bacerial inactivity of N-acetylcysteine (NAC) and its interaction with penicillin and aminocyclitol antibiotics was evaluated. NAC inhibited growth of both gram-negative and gram-positive bacteria. Strains of Pseudomonas aeruginosa were more susceptible than other microorgainsms tested. P. aeruginosa strains were inhibited synergistically by NAC and carbenicillin or ticarcillin. However, NAC antagonized the activity of gentamicin and tobramycin. These findings have implications for the combined clinical use of NAC and aerosolized antibiotics and are also important for the processing of sputum specimens in the microbiology laboratory.

The effect of thyroxine and triiodothyronine on bacterial growth

1973 ◽  
Vol 19 (11) ◽  
pp. 1401-1405
Author(s):  
Nachman Garber ◽  
Batia Lupowitz-Donenfeld
Keyword(s):  
Bacterial Growth ◽  
Divalent Cations ◽  
Inhibitory Effect ◽  
Gram Negative Bacteria ◽  
Weak Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Similar Inhibitory Effect ◽  
Free Iodine

The effects of L-thyroxine, D-thyroxine, and 3,5,3′-triiodothyronine on the growth of several Gram-positive and Gram-negative bacteria were examined. The first two compounds, at a concentration of 7.7 × 10−5 M, were found to have a considerable inhibitory effect while 3,5,3′-triiodothyronine had a very weak effect on the growth of the Gram-positive bacteria examined. The growth of the Gram-negative bacteria was not inhibited under the same conditions.Potassium iodide, at the same concentration, was not inhibitory. Release of free iodine from the thyroxine preparation was also excluded as contributing to the thyroxine effect because it was shown to be less toxic than thyroxine for Bacillus cereus 569 and to exhibit a similar inhibitory effect on Gram-positive and Gram-negative bacteria.The inhibition of Gram-positive bacteria by L-thyroxine was reduced by cations such as Mn2+, Fe2+, and Ca2+. However, the hormones were more potent in their effect compared to EDTA in the same molar concentration and the inhibition exerted by them was not so easily abolished by the divalent cations as it was in the case of EDTA. Although chelation could contribute to the inhibition of the bacteria by the iodinated hormones, it seems that it is not the only factor involved.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Elaf Ayad Kadhem ◽  
Miaad Hamzah Zghair ◽  
Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽  
Hussam H. Tizkam ◽  
Shoeb Alahmad
Keyword(s):  
Antibacterial Activity ◽  
Magnesium Oxide ◽  
Diffusion Method ◽  
Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Magnesium Oxide Nanoparticles ◽  
Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

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