scholarly journals Antibacterial and Antifungal Activities of the Leaf Exudate of Aloe megalacantha Baker

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Demoze Asmerom ◽  
Tesfay Haile Kalay ◽  
Gebrehiwot Gebremedhin Tafere

Infectious diseases caused by fungi and bacteria are among the major causes of illness and death worldwide. This is mainly implicated by the antimicrobial resistance of the current treatment regimens. Since plant products are house stores of bioactive compounds, it is essential to screen plant-based antimicrobials to come up with novel medicines that counter the grave consequences of antimicrobial resistance. In the folk medicine of Ethiopia, Aloe megalacantha is used for the treatment of wound, dandruff, malaria, diabetes, impotence, colon cleansing, amoeba, ascariasis, abdominal pain, urine retention, snake bite, and evil eye. Hence, the present study was aimed to evaluate the antibacterial and antifungal effects of the leaf exudate of Aloe megalacantha. Agar well diffusion was employed to determine the antibacterial and antifungal effects. Six bacterial strains, namely, S. aureus (standard), S. aureus (clinical isolate), E. coli ATCC 25922 (standard), E. coli (clinical isolate), K. pneumoniae (standard), and P. aeruginosa ATCC 27853 (standard), and four fungal strains such as C. albicans, C. glabrata, C. tropicalis, and C. krusei were studied. The leaf exudate showed the highest activity against C. krusei with an average zone diameter of 22.49 ± 0.47 mm at 400 mg/mL. Among the bacterial species, S. aureus ATCC 29213 (standard) was the most sensitive with an average zone of diameter of 16.63 ± 0.12 mm at 200 mg/mL. Thus, the present findings support the folklore use of Aloe megalacantha for the treatment of different microbial infections.

2020 ◽  
Vol 20 (29) ◽  
pp. 2681-2691
Author(s):  
Athina Geronikaki ◽  
Victor Kartsev ◽  
Phaedra Eleftheriou ◽  
Anthi Petrou ◽  
Jasmina Glamočlija ◽  
...  

Background: Although a great number of the targets of antimicrobial therapy have been achieved, it remains among the first fields of pharmaceutical research, mainly because of the development of resistant strains. Docking analysis may be an important tool in the research for the development of more effective agents against specific drug targets or multi-target agents 1-3. Methods: In the present study, based on docking analysis, ten tetrahydrothiazolo[2,3-a]isoindole derivatives were chosen for the evaluation of the antimicrobial activity. Results: All compounds showed antibacterial activity against eight Gram-positive and Gram-negative bacterial species being, in some cases, more potent than ampicillin and streptomycin against all species. The most sensitive bacteria appeared to be S. aureus and En. Cloacae, while M. flavus, E. coli and P. aeruginosa were the most resistant ones. The compounds were also tested for their antifungal activity against eight fungal species. All compounds exhibited good antifungal activity better than reference drugs bifonazole (1.4 – 41 folds) and ketoconazole (1.1 – 406 folds) against all fungal species. In order to elucidate the mechanism of action, docking studies on different antimicrobial targets were performed. Conclusion: According to docking analysis, the antifungal activity can be explained by the inhibition of the CYP51 enzyme for most compounds with a better correlation of the results obtained for the P.v.c. strain (linear regression between estimated binding Energy and log(1/MIC) with R 2 =0.867 and p=0.000091 or R 2 = 0.924, p= 0.000036, when compound 3 is excluded.


Antibiotics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 631
Author(s):  
Irene Stefanini ◽  
Martina Boni ◽  
Paola Silvaplana ◽  
Paola Lovera ◽  
Stefania Pelassa ◽  
...  

In order to monitor the spread of antimicrobial resistance, the European Union requires hospitals to be equipped with infection control centers. With this aim, we analyzed 1583 bacterial strains isolated from samples of different origin from patients with community-onset and nosocomial infections in a public tertiary University Hospital on the outskirts of Turin, Italy. Statistical analyses of the isolates (source, type) and their antimicrobial resistance (AMR) were performed. The survey revealed infections associated with bacterial species considered as not-commensal and not-pathogenic, hence potentially emerging as new threats for human health. Conversely to the general observation of nosocomial strains being more resistant to antibiotics compared to community-acquired strains, nosocomial strains isolated in this study were more resistant only to 1/42 tested antibiotics (tetracycline). By adopting an ecological approach, we observed that blood infections are associated with the broadest range of species compared to infections affecting other areas and we obtained clear indications on the antibiotics that should be preferred in the treatment of infections at specific body sites. Future investigations carried out on a larger geographical scale will clarify whether these indications are limited to the geographical region investigated over this study, or whether the same trends are visible at national or international level.


2001 ◽  
Vol 45 (10) ◽  
pp. 2716-2722 ◽  
Author(s):  
P. L. Winokur ◽  
D. L. Vonstein ◽  
L. J. Hoffman ◽  
E. K. Uhlenhopp ◽  
G. V. Doern

ABSTRACT Escherichia coli is an important pathogen that shows increasing antimicrobial resistance in isolates from both animals and humans. Our laboratory recently described Salmonellaisolates from food animals and humans that expressed an identical plasmid-mediated, AmpC-like β-lactamase, CMY-2. In the present study, 59 of 377 E. coli isolates from cattle and swine (15.6%) and 6 of 1,017 (0.6%) isolates of human E. coli from the same geographic region were resistant to both cephamycins and extended-spectrum cephalosporins. AnampC gene could be amplified with CMY-2 primers in 94.8% of animal and 33% of human isolates. Molecular epidemiological studies of chromosomal DNA revealed little clonal relatedness among the animal and human E. coli isolates harboring the CMY-2 gene. The ampC genes from 10 animal and human E. coli isolates were sequenced, and all carried an identical CMY-2 gene. Additionally, all were able to transfer a plasmid containing the CMY-2 gene to a laboratory strain of E. coli. CMY-2 plasmids demonstrated two different plasmid patterns that each showed strong similarities to previously describedSalmonella CMY-2 plasmids. Additionally, Southern blot analyses using a CMY-2 probe demonstrated conserved fragments among many of the CMY-2 plasmids identified in Salmonella andE. coli isolates from food animals and humans. These data demonstrate that common plasmids have been transferred between animal-associated Salmonella and E. coli, and identical CMY-2 genes carried by similar plasmids have been identified in humans, suggesting that the CMY-2 plasmid has undergone transfer between different bacterial species and may have been transmitted between food animals and humans.


2019 ◽  
Vol 4 (4) ◽  
pp. 209-215
Author(s):  
D. Joshi ◽  
R. Narigara ◽  
G. Jani ◽  
K. Parikh

A new class of fluorobenzimidazole derivatives (IIIa-j)was synthesized to investigate their antimicrobial potential. All the compounds were prepared by multiple step synthesis, initiating from the synthesis of 5-(difluoromethoxy)-1H-benzimidazole-2-thiol (I). The compound I was further reacted with different derivatives of 2-chloro-N-phenylacetamide (IIa-j) prepared by reacting differently substituted anilines with chloroacetylchloride and triethylamine in DMF (solvent); resulting in formation of fluorobenzimidazoles IIIa-j. The compounds IIIa-j were characterized by spectral analysis viz. 1H NMR, 13C NMR, mass spectra, elemental analysis and IR. All these compounds were screened in vitro for their antimicrobial activity against Gram-positive (S. aureus and E. faecalis) and Gram-negative bacterial (E. coli and P.aeruginosa) strains as well as fungi (A. niger and C. albicans). Some of the compounds exhibited promising results (in MIC) against Gram-negative bacterial strains.


1998 ◽  
Vol 66 (6) ◽  
pp. 2410-2419 ◽  
Author(s):  
Carol L. Wells ◽  
Elisabeth M. A. van de Westerlo ◽  
Robert P. Jechorek ◽  
Holly M. Haines ◽  
Stanley L. Erlandsen

ABSTRACT Cytochalasin-induced actin disruption has often been associated with decreased bacterial internalization by cultured epithelial cells, although polarized enterocytes have not been systematically studied. In assays using confluent polarized HT-29 enterocytes, cytochalasin D appeared to increase internalization of wild-type Salmonella typhimurium, Proteus mirabilis, and Escherichia coli. HeLa and HEp-2 epithelial cells, as well as HT-29 and Caco-2 enterocytes, were used to clarify this unexpected observation. Resulting data showed that cytochalasin D was associated with increased internalization of S. typhimurium and P. mirabilis by both HT-29 and Caco-2 enterocytes and with increased internalization of E. coli by HT-29 enterocytes; with either HeLa or HEp-2 cells, cytochalasin was associated with no change or a decrease in internalization of these same bacterial strains. Cytochalasin caused decreased internalization ofListeria monocytogenes by HT-29, Caco-2, HeLa, and HEp-2 cells, indicating that cytochalasin did not consistently augment bacterial internalization by polarized enterocytes. Fluorescein-labeled phalloidin confirmed marked disruption of filamentous actin in cytochalasin-treated HT-29, Caco-2, HeLa, and HEp-2 cells. Cytochalasin had no noticeable effect on epithelial viability but caused distorted apical microvilli, cell rounding, and separation of adjacent enterocytes in confluent cultures (with a corresponding decrease in transepithelial electrical resistance). Scanning electron microscopy showed that cytochalasin-induced enhanced bacterial internalization was associated with preferential bacterial adherence on the exposed enterocyte lateral surface. Colchicine, used to disrupt microtubules, had no noticeable effect on bacterial internalization by HT-29 or Caco-2 enterocytes. These data indicated that for HT-29 and Caco-2 enterocytes, cytochalasin-induced disruption of filamentous actin might augment internalization of some bacterial species by a mechanism that appeared to involve exposure of the enterocyte lateral surface.


2021 ◽  
Vol 17 (3) ◽  
pp. 160-170
Author(s):  
Van Tien Dung ◽  
Huynh Nguyen Van Anh ◽  
Pham Van Ngot ◽  
Dang Thi Ngoc Thanh

The study aimed to supplement data on a plant that was considered a folk medicine of Vietnam. Morphological and microscopic anatomical characteristics of this species which were adapted to the frequently flooded habitat of the reserve was studied and analyzed. Alcoholic extracts of each stem, leaf and root part were recovered using a rotary evaporator. The inhibitory ability on bacterial strains including Bacillus cereus, B. subtilis and Escherichia coli was tested through agar plate diffusion method. The result showed that the stem and leaf extracts were effective against all three bacterial strains, while the root extracts had no effect against E. coli.


2021 ◽  
Vol 19 (3) ◽  
pp. 513-524
Author(s):  
Natcha Chawnan ◽  
◽  
Kannika Na Lampang ◽  
Raktham Mektrirat ◽  
Nattakarn Awaiwanont ◽  
...  

This research aimed to assess the occurrence of bacterial pathogens and their antimicrobial resistance in dogs presenting with canine periapical tooth abscesses. Sample swabs were performed on 45 dogs who had undergone dental surgery between January 2019 and August 2020 at the Veterinary Teaching Hospital, Chiang Mai University. Samples were analyzed within 24 hours at Veterinary Diagnostic Laboratory, Chiang Mai University to identify any bacterial species and to investigate their potential antimicrobial susceptibility according to CLSI guidelines. A high proportion of gram-negative and facultative species were identified. Out of the 17 species obtained, Pseudomonas aeruginosa (34.6 %) was determined to be the predominant species followed by Escherichia coli (15.4%) and Klebsiella pneumoniae (11.5%), respectively. P. aeruginosa was highly resistant (100.0%) to ampicillin and clindamycin, while E. coli and K. pneumoniae were found to be highly resistant (100.0%) to clindamycin in terms of antimicrobial susceptibility. However, E. coli was more resistant to enrofloxacin, gentamicin, and norfloxacin than K. pneumoniae. When focusing on the resistance rates of all species, clindamycin exhibited the highest degree of resistance, followed by ampicillin and amoxicillin, respectively. Amoxicillin-clavulanate is an empirical antibiotic in our area that has exhibited a resistance rate of 48.7%. The outcomes of our study have suggested that fluoroquinolone and aminoglycoside could be used to treat canine periapical tooth abscesses. However, the renal effect of these drugs must be considered. Importantly, antibiotic selection must depend upon the results of bacterial culture and antimicrobial susceptibility tests in order to reduce any potential antimicrobial resistance issues.


2021 ◽  
Vol 17 ◽  
pp. 711-718
Author(s):  
Zafar Iqbal ◽  
Lijuan Zhai ◽  
Yuanyu Gao ◽  
Dong Tang ◽  
Xueqin Ma ◽  
...  

The diazabicyclooctane (DBO) scaffold is the backbone of non-β-lactam-based second generation β-lactamase inhibitors. As part of our efforts, we have synthesized a series of DBO derivatives A1–23 containing amidine substituents at the C2 position of the bicyclic ring. These compounds, alone and in combination with meropenem, were tested against ten bacterial strains for their antibacterial activity in vitro. All compounds did not show antibacterial activity when tested alone (MIC >64 mg/L), however, they exhibited a moderate inhibition activity in the presence of meropenem by lowering its MIC values. The compound A12 proved most potent among the other counterparts against all bacterial species with MIC from <0.125 mg/L to 2 mg/L, and is comparable to avibactam against both E. coli strains with a MIC value of <0.125 mg/L.


Author(s):  
Fernanda Loayza ◽  
Jay P. Graham ◽  
Gabriel Trueba

Recent studies have found limited associations between antimicrobial resistance (AMR) in domestic animals (and animal products), and AMR in human clinical settings. These studies have primarily used Escherichia coli, a critically important bacterial species associated with significant human morbidity and mortality. E. coli is found in domestic animals and the environment, and it can be easily transmitted between these compartments. Additionally, the World Health Organization has highlighted E. coli as a “highly relevant and representative indicator of the magnitude and the leading edge of the global antimicrobial resistance (AMR) problem”. In this paper, we discuss the weaknesses of current research that aims to link E. coli from domestic animals to the current AMR crisis in humans. Fundamental gaps remain in our understanding the complexities of E. coli population genetics and the magnitude of phenomena such as horizontal gene transfer (HGT) or DNA rearrangements (transposition and recombination). The dynamic and intricate interplay between bacterial clones, plasmids, transposons, and genes likely blur the evidence of AMR transmission from E. coli in domestic animals to human microbiota and vice versa. We describe key factors that are frequently neglected when carrying out studies of AMR sources and transmission dynamics.


2016 ◽  
Vol 5 (09) ◽  
pp. 4885 ◽  
Author(s):  
Khushbu Pandey ◽  
Mahendra Singh* ◽  
Bharat Pandey ◽  
Anshulika Upadhyaya ◽  
Kamal K. Pande

The present study was carried out for phytochemical screening of principle bioactive compounds and antimicrobial activity in Elaeocarpus ganitrus Roxb., Phytochemical analysis revealed the presence of saponin, terpenoid, steroid, saponin, flavonoid, tannin and alkaloid. The petroleum, ether, chloroform, methanol, acetone and aqueous extracts were subjected to antimicrobial activity against bacterial strains Staphylococcus aureus, Pseudomonas, E. coli and Bacillus subtilis against anti-fungal strains A.awamori, A.fumigatus, Rhizopus oryzae, Trichoderma viridae and C.oryzae. The antibacterial and antifungal activity was evaluated by disc-diffusion method.


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