scholarly journals Screening of Antibacterial Efficacy of Aloe Barbadensis Miller (Aloe Vera) Using Leaf Extract against Different Bacterial Strains

Author(s):  
Pravanchana Singh

The current research was aimed to evaluate in vitro antibacterial activity of crude extract prepared from leaves of Aloe vera plant. The extract of Aloe vera was prepared in Methanol. Two extracts were prepared, one from whole leaf powder and the other from fresh Aloe vera gel. To determine the antibacterial efficacy of the given plant, Kirby-bauer disk diffusion method was performed. The standard antibiotic used was Gentamicin. Gentamicin showed significant antimicrobial efficacy against E.coli and Bacillus subtilis forming a zone of inhibition of 34mm in both. This research provides information about antibacterial susceptibility of aloe vera leaves (leaf powder and fresh gel) against two different bacteria: E.coli which is a gram-negative bacteria and Bacillus subtilis which is a gram-negative bacteria. The antibacterial susceptibility test showed that the extract of leaf and the gel of Aloe vera inhibited the growth of both microorganisms during test. Growth of E,coli strain were inhibited more as compared to Bacillus subtilis because gram negative bacteria do not have lipopolysaccharide layer in their cell wall. Also the fresh gel Extract was more effective as compared to Aloe vera leaf powder.

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S386-S386
Author(s):  
Susan M Novak-Weekley ◽  
Aye Aye Khine ◽  
Tino Alavie ◽  
Namidha Fernandez ◽  
Laxman Pandey ◽  
...  

Abstract Background Conventional antimicrobial susceptibility testing (AST) of microorganisms from positive blood cultures (PBC) can take ≥ 2 days. In order to improve the turnaround time for AST on a PBC, CLSI and EUCAST have made efforts to standardize procedures for disk diffusion (DD) direct from a PBC. Qvella Corporation (Richmond Hill, ON, Canada) has recently developed FAST-Prep, an automated centrifugal sample preparation system that rapidly delivers a Liquid Colony consisting of a purified, concentrated, viable cell suspension directly from a PBC. This study was performed to investigate the feasibility of DD AST off of a PBC using a FAST-Prep Liquid Colony. Methods Contrived PBC samples were prepared by spiking 6 species of Gram-positive and 4 species of Gram-negative bacteria (3-5 strains per species) into FA® Plus bottles and incubating in the BACT/ALERT® VIRTUO® System (bioMerieux, Durham, NC). After positivity, 3 mL of PBC was added to the FAST-Prep cartridge. After 20 minutes of processing in the FAST-Prep instrument, the Liquid Colony was removed from the cartridge and a 0.5 McFarland sample was prepared for DD AST. In parallel, the DD AST from a PBC was performed using 4 drops of PBC (CLSI direct method). Both methods were compared to conventional colony-based DD AST. After 16-18 hours of incubation zone diameters and S/I/R interpretations were determined. Categorical agreement (CA) and errors for both DD AST methods were calculated. In addition, colony plate counting was performed on 0.5 McFarland suspensions of Liquid Colony and the plate colony to determine biomass recovery and sample purity. Results CA for a FAST-Prep DD AST for Gram-positive and Gram-negative bacteria was 95.6% and 98.6%, respectively, compared to CA for CLSI DD AST of 77.2% and 81.9%, respectively. Biomass in the Liquid Colony was 7.2x108 and 1.2x109 CFU for Gram-positive and Gram-negative bacteria, respectively. Cell concentration in the 0.5 McFarland suspension of the Liquid Colony was 3.7x107 and 5.9x107 CFU/mL for Gram-positive and Gram-negative bacteria, respectively, which was similar to the concentration for the reference colony suspension. Conclusion The results support the potential role of FAST-Prep in providing a Liquid Colony for use in rapid AST. Disclosures Susan M. Novak-Weekley, PhD, D(ABMM), Qvella (Employee, Shareholder) Aye Aye Khine, PhD, Qvella (Employee, Shareholder) Tino Alavie, PhD, Qvella (Employee) Namidha Fernandez, MS, Qvella (Employee) Laxman Pandey, MS, Qvella (Employee) Abdossamad Talebpour, PhD, Qvella (Employee, Shareholder)


2012 ◽  
Vol 7 (5) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Alexis Peña ◽  
Luis Rojas ◽  
Rosa Aparicio ◽  
Libia Alarcón ◽  
José Gregorio Baptista ◽  
...  

The essential oil of the leaves of Espeletia nana Cuatrec, obtained by hydrodistillation, was analyzed by GC-MS, which allowed the identification of 24 components, which made up 99.9% of the oil. The most abundant compounds were α-pinene (38.1%), β-pinene (17.2%), myrcene (15.0%), spathulenol (4.2%), bicyclogermacrene (4.0%), α-zingiberene (4.0%), and γhimachalene (3.7%). Antibacterial activity was tested against Gram-positive and Gram-negative bacteria using the agar disk diffusion method. Activity was observed only against Gram-positive bacteria. MIC values were determined for Staphylococcus aureus ATCC 25923(200 μg/mL) and Enterococcus faecalis ATCC 29212 (600 μg/mL).


2013 ◽  
Vol 11 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Igor Stojanovic ◽  
Niko Radulovic ◽  
Vladimir Cvetkovic ◽  
Tatjana Mitrovic ◽  
Slavisa Stamenkovic

Antimicrobial activity of methanol extracts of four Parmeliaceae lichens (Hypogymnia physodes (L.) Nyl., Evernia prunastri (L.) Ach., Flavoparmelia caperata (L.) Hale and Parmelia sulcata Taylor) against a panel of microbial strains (11 Gram-positive (Enterococus sp., Bacillus subtilllis, Sarcina lutea, Micrococus luteus, Staphylococcus aureus, Clostridium sporogenes) and Gram-negative bacteria (Escherichia coli, Proteus vulgaris, Salmonela enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae), the filamentous fungus A. niger and the yeast C. albicans) was assayed using a disk diffusion method (1 mg of the extract per disc; extracts were dissolved in methanol, 25 mg/mL). All tested extracts showed moderate antimicrobial activity. Multivariate statistical treatment (agglomerative hierarchical clustering analysis, AHC) of the obtained results allowed grouping of the samples according to their antimicrobial potential against different strains: antimicrobial profile of H. physodes and E. prunastri extracts were comparable; the similar is true for F. caperata and P. sulcata samples. In addition, based on the similarities/ dissimilarities in their susceptibility toward the tested extracts, two groups of microorganisms could be distinguished: Group I - P. vulgaris, K. pneumoniae (Gram-negative bacteria), A. niger and C. albicans; Group II - E. coli, S. enteritidis, P. aeruginosa (Gram-negative bacteria) and all of the assayed Gram-positive strains.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S93-S93
Author(s):  
Andrew Walkty ◽  
Heather Adam ◽  
Melanie Baxter ◽  
Amina Henni ◽  
Philippe Lagace-Wiens ◽  
...  

Abstract Background Inadequate empiric antimicrobial therapy for Gram-negative bacteremia is associated with adverse clinical outcomes. The purpose of this study was to evaluate the proportion of Gram-negative bacterial isolates recovered from the bloodstream of patients attending Canadian emergency rooms (ERs) that remain susceptible to commonly prescribed antimicrobials. Methods Annually from 2007 to 2018, sentinel hospitals across Canada collected bloodstream isolates from patients attending ERs as part of the CANWARD study. Susceptibility testing was performed using broth microdilution as described by CLSI (data analysis limited to Gram-negative bacteria in the top 10 pathogens), with current CLSI breakpoints applied. Extended-spectrum β-lactamase (ESBL)-producing isolates were confirmed using the CLSI disk diffusion method. Results Gram-negative bacteria among the top 10 bloodstream pathogens for patients seen at ERs across Canada were: Escherichia coli (n = 2,414), Klebsiella pneumoniae (n = 573), Pseudomonas aeruginosa (n = 211), Proteus mirabilis (n = 119), and Enterobacter cloacae (n = 114). Aggregate susceptibility of these isolates to common antimicrobials was as follows (% susceptible [S]): meropenem 99.4% S, piperacillin–tazobactam 98.5% S, gentamicin 93.3% S, ceftriaxone 88.1% S, ciprofloxacin 81.4% S, TMP-SMX 73.5% S. The most active antimicrobials evaluated vs. E. coli were meropenem (100% S), piperacillin–tazobactam (98.8% S), and ceftriaxone (93.3% S). Ceftriaxone susceptibility among E. coli isolates declined from 95.4% in 2007 to 89.8% in 2018. The average proportion of E. coli isolates that harbored an ESBL enzyme increased from 3.4% in the first three study years to 8.4% in the last three study years. The most active antimicrobials evaluated vs. K. pneumoniae isolates were meropenem (99.7% S), piperacillin–tazobactam (98.8% S), gentamicin (97.7% S), and ceftriaxone (96.9% S). Conclusion The most consistently active antimicrobials for empiric treatment of patients at Canadian ERs with Gram-negative bacteremia are meropenem and piperacillin–tazobactam. Ceftriaxone susceptibility among E. coli has declined over the last 12 years, mostly related to an increase in ESBL-producing isolates. Disclosures All authors: No reported disclosures.


Chemotherapy ◽  
2017 ◽  
Vol 62 (3) ◽  
pp. 194-198 ◽  
Author(s):  
Socorro Leyva-Ramos ◽  
Denisse de Loera ◽  
Jaime Cardoso-Ortiz

Background: Fluoroquinolones are widely prescribed synthetic antimicrobial agents. Quinolones act by converting their targets, gyrase and topoisomerase IV, into toxic enzymes that fragment the bacterial chromosome; the irreversible DNA damage eventually causes the killing of bacteria. Thorough knowledge of the structure-activity relationship of quinolones is essential for the development of new drugs with improved activity against resistant strains. Methods: The compounds were screened for their antibacterial activity against 4 representing strains using the Kirby-Bauer disk diffusion method. Minimal inhibitory concentration (MIC) was determined by measuring the diameter of the inhibition zone using concentrations between 250 and 0.004 μg/mL. Results: MIC of derivatives 2, 3, and 4 showed potent antimicrobial activity against gram-positive and gram-negative bacteria. The effective concentrations were 0.860 μg/mL or lower. MIC for compounds 5-11 were between 120 and 515 μg/mL against Escherichia coli and Staphylococcus aureus, and substituted hydrazinoquinolones 7-10 showed poor antibacterial activity against gram-positive and gram-negative bacteria compared with other quinolones. Conclusion: Compounds obtained by modifications on C-7 of norfloxacin with the acetylated piperazinyl, halogen atoms, and substituted hydrazinyl showed good in vitro activity - some even better than the original compound.


Diseases ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 15
Author(s):  
Ram Shankar Prasad Sah ◽  
Binod Dhungel ◽  
Binod Kumar Yadav ◽  
Nabaraj Adhikari ◽  
Upendra Thapa Shrestha ◽  
...  

Background: Antimicrobial resistance (AMR) among Gram-negative pathogens, predominantly ESBL-producing clinical isolates, are increasing worldwide. The main aim of this study was to determine the prevalence of ESBL-producing clinical isolates, their antibiogram, and the frequency of ESBL genes (blaTEM and blaCTX-M) in the clinical samples from patients. Methods: A total of 1065 clinical specimens from patients suspected of heart infections were collected between February and August 2019. Bacterial isolates were identified on colony morphology and biochemical properties. Thus, obtained clinical isolates were screened for antimicrobial susceptibility testing (AST) using modified Kirby–Bauer disk diffusion method, while ESBL producers were identified by using a combination disk diffusion method. ESBL positive isolates were further assessed using conventional polymerase chain reaction (PCR) to detect the ESBL genes blaTEM and blaCTX-M. Results: Out of 1065 clinical specimens, 17.8% (190/1065) showed bacterial growth. Among 190 bacterial isolates, 57.4% (109/190) were Gram-negative bacteria. Among 109 Gram-negative bacteria, 40.3% (44/109) were E. coli, and 30.2% (33/109) were K. pneumoniae. In AST, 57.7% (n = 63) Gram-negative bacterial isolates were resistant to ampicillin and 47.7% (n = 52) were resistant to nalidixic acid. Over half of the isolates (51.3%; 56/109) were multidrug resistant (MDR). Of 44 E. coli, 27.3% (12/44) were ESBL producers. Among ESBL producer E. coli isolates, 58.4% (7/12) tested positive for the blaCTX-M gene and 41.6% (5/12) tested positive for the blaTEM gene. Conclusion: Half of the Gram-negative bacteria in our study were MDR. Routine identification of an infectious agent followed by AST is critical to optimize the treatment and prevent antimicrobial resistance.


2018 ◽  
Vol 10 (04) ◽  
pp. 432-436 ◽  
Author(s):  
Nidhi Bhardwaj ◽  
Surbhi Khurana ◽  
Minu Kumari ◽  
Rajesh Malhotra ◽  
Purva Mathur

ABSTRACT INTRODUCTION: Antimicrobial resistance is an increasing problem worldwide especially among the surgical site infections (SSIs). SSI is becoming more serious due to hospital-acquired infections/nosocomial infections, which further leads to the overuse of broad-spectrum antibiotics. To investigate the antimicrobial resistance patterns among Gram-negative bacteria in SSI in in- and out-patients the present study was designed. METHODOLOGY: During the 4 years (January 2013–December 2016), the antimicrobial resistant pattern was studied in the admitted patients and in the patients who were followed up to the outpatients department (OPD) after discharge. Antimicrobial resistance pattern testing was done by the disk diffusion method on Mueller-Hinton agar and by E-test for ten antibiotics according to The Clinical and Laboratory Standards Institute guidelines for Gram-negative bacilli. RESULTS: A total of 2,447 strains were isolated from the studied population on over the period of 4 years. Of 2447, 1996 (81%) were isolated from patients who had SSI during the hospital stay, and 451 (18%) were from patients who attended the OPD after discharge. In the outpatients, who followed up in the OPD for the SSI, Escherichia coli (148), and Pseudomonas aeruginosa (93), whereas in the patients who develop SSI during their hospital stay, Acinetobacter baumannii (622), E. coli (424), and Klebsiella pneumoniae (315) were found to be common. A very high resistance pattern was observed in both the studied groups; however, a higher resistance pattern was seen in in-patients as compared to outpatients. CONCLUSION: In our study, we have reported resistance pattern in Gram-negative bacteria isolated from the patients who were came for the follow as well as in the inpatients. For the outpatients, it can be concluded that it could be a community-acquired infection which is also an alarming condition for our society.


2016 ◽  
Vol 8 (3) ◽  
pp. 1497-1500
Author(s):  
Vandana Gupta ◽  
Rakesh Kumar ◽  
Deepika Chaudhary ◽  
Nirmal Yadav

The present study was aimed to examine and compare the antibacterial activity of hot methanolic extract of medicinal plants viz. Portulaca oleracea (purslane), Syzygium cumini (L.) (jamun), Psidium guajava (L.) (guava). Antibacterial activity was carried by using agar well diffusion method, against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli). Results indicated that all the three plant extracts possess antibacterial property against Gram-positive bacteria and no activity was found against Gram-negative bacteria. Moderate zone of inhibition against Staphylococcus aureus and Bacillus subtilis was exhibited by S. cumini (L.) (11mm and 12mm) and P. guajava (L.) (10mm and 11mm) and weak zone of inhibition was exhibited by P. oleracea (5 mm and 6mm). In conclusion, S. cumini (L.) and P. guajava (L.) possess bettercapabilities of being a good candidate in search for natural antibacterial agent against infections and diseases causing Gram-positive bacteria as compared to P. oleracea.


Antibiotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 143 ◽  
Author(s):  
Márió Gajdács ◽  
Katalin Burián ◽  
Gabriella Terhes

Background: Urinary tract infections (UTIs) are one of the most common infections in the human medicine, both among outpatients and inpatients. There is an increasing appreciation for the pathogenic role of non-fermenting Gram-negative bacteria (NFGNBs) in UTIs, particularly in the presence of underlying illnesses. Methods: The study was carried out using data regarding a 10-year period (2008–2017). The antimicrobial susceptibility testing was performed using the disk diffusion method, E-tests, and broth microdilution. Results: NFGNB represented 3.46% ± 0.93% for the outpatients, while 6.43% ± 0.81% of all positive urine samples for the inpatients (p < 0.001). In both groups, Pseudomonas spp. (78.7% compared to 85.1%) and Acinetobacter spp. (19.6% compared to 10.9%), were the most prevalent. The Acinetobacter resistance levels were significantly higher in inpatients isolates (p values ranging between 0.046 and <0.001), while the differences in the resistance levels of Pseudomonas was not as pronounced. The β-lactam-resistance levels were between 15–25% and 12–28% for the Acinetobacter and Pseudomonas spp., respectively. 4.71% of Acinetobacter and 1.67% of Pseudomonas were extensively drug resistant (XDR); no colistin-resistant isolates were recovered. Conclusions: Increasing resistance levels of the Acinetobacter spp. from 2013 onward, but not in the case of the Pseudomonas spp. Although rare, the drug resistant NFGNB in UTIs present a concerning therapeutic challenge to clinicians with few therapeutic options left.


10.3823/826 ◽  
2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Abdelraouf A Elmanama ◽  
Mariam R. Al-Reefi ◽  
Madleen A. Shamali ◽  
Haya I Hemaid

Background: Food is fundamental for everyone’s life. Therefore, the safety of food we consume is a priority. Gram-negative bacteria are important and common cause of human infections and could be transmitted through food handling and consumption. Carbapenemase-producing Gram-negative (CRGN) bacteria are becoming a global threat. Infections caused by CRGN are hard to cure because the carbapenems are last resort drugs for treatment. The main objective of this research is to determine the occurrence of Carbapenem-resistance among Gram-negative bacteria from poultry samples. Results:  Two hundred twenty samples (chicken litters, water, chicken feed, and intestinal content) were collected from slaughterhouses, farms, and homes from different locations in Gaza strip. Samples were cultured onto MacConkey and Blood agar plates. Gram negative isolates were identified using conventional techniques. Disk diffusion method (based on CLSI recommendations) was used to determine the antimicrobial susceptibility against 14 antimicrobials including two carbapenems (Meropenem and imipenem). Carbapenemase production was detected by the Modified Hodge Test (MHT). The Multiple Antibiotic Resistance (MAR) index for each isolate was calculated. Escherichia species were the most frequent isolates (39.5%), followed by non-lactose fermenting Enterobacteriaceae (29.5%), other lactose fermenting Enterobacteriaceae (29%). The lowest frequency was for non-fermenting Gram-negative bacilli (4.8%). Most isolates were resistant to most antimicrobial agents tested. A prominent exception was observed with meropenem, and amikacin with only 4% resistance. 41 isolates (34.7%) were resistance to imipenem. High level of intermediate results was detected for imipenem (45.2%). Among 124 isolates, 44 carbapenem-resistant (35.5%) were detected. None of the five meropenem resistant isolates and only five out of the 43 imipenem resistance isolates tested positive for carbapenemase production. Most isolates showed resistance to three or more antibiotics and are regarded as multidrug resistant strains. MDR isolates were present in 117 isolates (94.3%) with MARI index (higher than 0.3). Conclusion: Resistance to carbapenems as well as to other antimicrobials was high among GNB isolates as indicated by the MAR index. Concerned authorities should consider these alarming finding and implement an immediate monitoring program for poultry. Cross contamination, prevention measures should also be promoted and implemented.


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