American Type Culture Collection Strains Research Articles

In Vitro Antibacterial Activity of Ethanolic Extract of Neem Leave (Azadirachtaindica Linn) Against Clinical Isolates

Background: Emerging multidrug resistance amongst pathogens is making the choice of antibiotics for the management of infections extremely difficult and threatens the return of the pre-antibiotic era in healthcare settings. To tackle this menace, there is a growing need for exploring bioactive compounds derived from herbal extracts, which could be incorporated as alternative therapeutic agents in the antimicrobial therapy of such infections. Objectives: We evaluated the antibacterial activity of ethanolic extracts of Neem leaves against standard ATCC strains and the pathogens isolated from clinical specimens. Methods: This cross-sectional study was undertaken to assess in vitro antibacterial activity of different concentrations of ethanolic Neem extract against three ATCC (American-type culture collection) strains and 63 clinical isolates using the disk diffusion method. The minimum inhibitory concentration (MIC) of the extract against test isolates was determined by the Broth dilution method. Results: Neem extract exhibited the highest antimicrobial activity toward Escherichia coli ATCC-25922 followed by Staphylococcus aureus ATCC-25923 and Pseudomonas aeruginosa ATCC-27853 strains. Amongst the Gram-positive isolates, the extract exhibited significantly high antibacterial activity against S. aureus and Enterococcus spp. Amongst the Gram-negative isolates, high antibacterial activity was seen against E. coli followed by Klebsiella pneumoniae and Proteus mirabilis. In this study, the lowest MIC values were observed against E. coli followed by S.aureus, P. mirabilis, and K. pneumoniae. The highest MIC values of the extract were observed against non-fermenters, like P. aeruginosa and Acinetobacter spp. isolates. Conclusion: This study strongly depicts that the ethanolic extract of Neem leaves exhibits significant antibacterial activity not only against the standard ATCC strains but also against various clinical isolates

Repositioning of Disulfiram in Association with Vancomycin Against Enterococcus spp. MDR and XDR.

The identification of molecules that exhibit potent antibacterial activity and are capable of circumventing resistance mechanisms is an unmet need. The repositioning of approved drugs is considered an advantageous alternative in this case, and has gained prominence. In addition, drug synergism can reduce morbidity and mortality in the treatment of nosocomial infections caused by multi-drug resistant microorganisms (MDR). Whole cell growth inhibition assays were used to define the in vitro antibacterial activity of disulfiram against two standard American Type Culture Collection (ATCC) strains and 35 clinical isolates of vancomycin-resistant enterococci (VRE). The ability of disulfiram to synergize with vancomycin was determined by fractional inhibitory concentration index, preceded by the checkerboard test. The cytotoxicity of drugs alone and in combination was tested against Raw 264.7 cells. Disulfiram exhibited potent antibacterial activity against VRE (MIC 16-64µgmL-1). Results: Associated with vancomycin, disulfiram it had a reduction in MIC of up to 64 times, with values of 0.5-4µgmL-1. Vancomycin had a MIC of 128-1024µgmL-1; combined, reduced this value by up to 124 times (8µgmL-1), with synergy occurring against all strains. Disulfiram and vancomycin alone and in combination did not show cytotoxicity against the eukaryotic cell line. Based on these results, we suggest that the redirection of disulfiram may be promising in the treatment of infections caused by VRE, since it was able to potentiate the activity of vancomycin against the strains, being able to act as an adjuvant in cases of serious infections caused by Enterococcus.

In vitro study of elution kinetics and biological activity of piperacillin/tazobactam and gentamicin in acrylic bone cement

BackgroundAntibiotics differ in their elution characteristics from bone cement. But no such data is available on piperacillin and tazobactam. Therefore, we performed an in vitro observational study to examine (1) in vitro elution characteristics of piperacillin and tazobactam from bone cement, (2) their biological activity using minimum inhibitory concentration and (3) elution characteristics and biological activity when combined with gentamicin in bone cement. HypothesisThe null hypothesis was that piperacillin and tazobactam after elution from bone cement can achieve concentrations higher than minimum inhibitory concentration. Material and methodsForty milligrams bone cement was mixed with the following combination of antibiotics: without any antibiotic (sample A, control), 4g/0.50g piperacillin/tazobactam (sample B), 6g/0.75g piperacillin/tazobactam (sample C), 8g/1.0g piperacillin/tazobactam (sample D) and 4g/0.50g piperacillin/tazobactam and 400mg gentamicin (sample E). Samples were analysed on reverse-phase ultra-high-performance liquid chromatography. Antibacterial activity in the elute were tested against standard American Type Culture Collection (ATCC) strains. ResultsDetectable drug elution for piperacillin and tazobactam was seen till 21days. Peak drug levels for all formulations were seen at 48hours (140.8 & 297.5μg/mL for samples B of piperacillin and tazobactam respectively). About 0.83–1.24% of piperacillin and 23.17–29.17% of tazobactam were released from the samples. Gentamicin improved elution of piperacillin and tazobactam: 140.8 vs. 919.9μg/mL (p=0.000) for samples B & E of piperacillin respectively and 297.5 & 1138.4μg/mL (p=0.001) for samples B & E of tazobactam respectively at 2days. Sample E showed complete inhibition of tested microorganisms, while B sample was microbiologically less active compared to E on day 5. ConclusionsPiperacillin and tazobactam eluted successfully from bone cement and also retained antimicrobial activity after elution. Maximum elution was seen up to day 2 after which it reduced drastically. Antimicrobial action was seen up to 7days. Level of evidenceIII; comparative study.

Expression of full and fragment-B of diphtheria toxin genes in Escherichia coli for generating of recombinant diphtheria vaccines.

PurposeIn the present study, whole diphtheria toxin (dt) and fragment B (dtb) genes from Corynebacterium diphtheriae Park William were cloned into Escherichia coli, the purified expressed proteins were evaluated for ultimately using as a candidate vaccine.Materials and MethodsThe dt and dtb genes were isolated from bacterial strain ATCC (American Type Culture Collection) no. 13812. Plasmid pET29a+ was extracted by DNA-spin TM plasmid purification kit where genes were inserted using BamHI and HindIII-HF. Cloned pET29a+dt and pET29a+dtb plasmids were transformed into E. coli BL21(DE3)PlysS as expression host. The identity of the sequences was validated by blasting the sequence (BLASTn) against all the reported nucleotide sequences in the NCBI (National Center for Biotechnology Information) GenBank. Production of proteins in high yield by different types and parameters of fermentation to determine optimal conditions. Lastly, the purified concentrated rdtx and rdtb were injected to BALB/c mice and antibody titers were detected.ResultsThe genetic transformation of E. coli DH5α and E. coli BL21 with the pET-29a(+) carrying the dt and dtb genes was confirmed by colony polymerase chain reaction assay and were positive to grow on Luria-Bertani/kanamycin medium. The open reading frame of dt and dtb sequences consisted of 1,600 bp and 1,000 bp, were found to be 100% identical to dt and dtb sequence of C. diphtheriae (accession number KX702999.1 and KX702993.1) respectively. The optimal condition for high cell density is fed-batch fermentation production to express the rdtx and rdtb at 280 and 240 Lf/mL, dissolved oxygen was about 24% and 22% and the dry cell weight of bacteria was 2.41 g/L and 2.18 g/L, respectively.ConclusionThis study concluded with success in preparing genetically modified two strains for the production of a diphtheria vaccine, and to reach ideal production conditions to achieve the highest productivity.

Efficacy of voriconazole and amphotericin B in corneal preservative media.

Purpose:To evaluate the efficacy of voriconazole and amphotericin B in McCarey–Kaufman (MK) media.Methods:MK media vials were supplemented with either voriconazole at 1, 2, 20, 50, 100 μg/mL or amphotericin B at 0.5, 1, 2, 10, 20 μg/mL. The standard inoculum of the American Type Culture Collection (ATCC) strain of Candida albicans, Aspergillus flavus, and Fusarium keratinoplasticum was added to the set of vials. The efficacy outcomes were calculated as ‘viable fungal colony counts’ determined from the samples taken on Days 0 and 4. MK media containing fungal inoculum but without antifungal supplements were used as control.Results:In the voriconazole arm, on Day 4, a reduction in the colony count was observed for Candida albicans (1 μg/mL, 36%; 100 μg/mL, 100%), Aspergillus flavus (1 μg/mL, 53.8%; 100 μg/mL, 80.4%), and Fusarium keratinoplasticum (1 μg/mL, 39.0%; 100 μg/mL, 72.2%). Similarly, in the amphotericin B arm, on Day 4, a reduction in the colony count was observed for Candida albicans (0.5 μg/mL; 99.9%; 20 μg/mL, 100%), Aspergillus flavus (0.5 μg/mL, 65.2%; 20 μg/mL, 84.8%), and Fusarium keratinoplasticum (0.5 μg/mL, 90.1%; 20 μg/mL, 100%).Conclusion:Compared to voriconazole, the addition of amphotericin B significantly reduces fungal contamination in MK media.

1063. ARGONAUT-V: Susceptibility of Multidrug-Resistant (MDR) Pseudomonas aeruginosa to Cefepime-Taniborbactam

1063. ARGONAUT-V: Susceptibility of Multidrug-Resistant (MDR) <i>Pseudomonas aeruginosa</i> to Cefepime-Taniborbactam

1055. ARGONAUT-IV: Susceptibility of Carbapenem-resistant Klebsiellae to Ceftibuten/VNRX-5236

1055. ARGONAUT-IV: Susceptibility of Carbapenem-resistant <i>Klebsiellae</i> to Ceftibuten/VNRX-5236

133. ARGONAUT-III: Susceptibility of Carbapenem-resistant Klebsiellae to Cefepime-Taniborbactam

133. ARGONAUT-III: Susceptibility of Carbapenem-resistant <i>Klebsiellae</i> to Cefepime-Taniborbactam

English

Infectious diseases, including skin infections, have always been treated by plants and other natural products since ancient times. This study investigated the antimicrobial activity of nine medicinal plant species from Gons&eacute; Forest and Bangreweogo Park, Burkina Faso on seven microbial strains involved in skin infections. Sixty-eight organic and aqueous extracts from leaves, stem and root barks of the nine plants were tested on five bacterial and two fungal American Type Culture Collection (ATCC) strains using the disk diffusion and microdilution methods. Twenty-eight extracts (41.17%) from eight of the plants differently inhibited bacteria and fungi, the exception being Wissadula amplissima specie. Gram-positive Cocci (GPC) were the most sensitive to the extracts. Eleven extracts had a Minimum Inhibitory Concentration (MIC) lower than 1 mg/ml (MIC &lt; 1 mg/ml). The extracts of Opilia celtidifolia gave the largest zones of inhibition ranging from 21.67 to 24.33 mm at 100 to 300 mg/ml on GPC and Candida albicans. Its MIC varied from 0.03 to 0.06 mg/ml on Streptococcus pyogenes, and from 0.07 to 0.24 mg/ml on Streptococcus agalactiae. Ethanolic extracts (80 and 96%) of Lawsonia inermis had MIC ranging from 0.29 to 9.37 mg/ml on the sensitive strains. The variable inhibitory activity displayed by the plants confirmed in part their traditional use in the treatment of some bacterial and fungal skin infections. Key words: Infectious diseases, inhibitory activity, plant extracts, minimal bactericidal concentration (MBC), minimum inhibitory concentration (MIC), skin infections.

Evaluation of Antimicrobial Effect of Oenothera biennis by Using Different Concentrations of Extract against Staphylococcus Aureus -An experimental study

Background: Staphylococcus aureus is a superbug which is infamous for causing wound infections. Unfortunately it is developing resistance quickly against commonly used antibiotics. Antimicrobial drugs effective against methicillin resistant staphylococcus aureus are too expensive to afford by impoverish population in our country. However, herbal medicines are seen to be equally effective with less severe adverse effects. There is need to explore alternative medicines of botanical origin to cure dangerous bacteria. Oenothera biennis contains phytochemicals which have antimicrobial activity against some gram negative and gram positive microorganisms. Objectives: To evaluate the minimum inhibitory concentration of Oenothera biennis seed extract against staphylococcus aureus by using different concentrations. Study Design: In Vitro antibacterial study. Settings: The study was conducted in microbiology laboratory of Shaikh Zayed Medical Complex, Lahore. Duration: One year. Methodology: Oenothera biennis extract was prepared in 95% Ethanol in biochemistry laboratory of Pakistan Council of Scientific and Industrial Research (PCSIR) Lahore. Staphylococcus aureus isolates were procured from microbiology laboratory and American Type Culture Collection (ATCC) strains used as quality control for MSSA &amp; MRSA, were purchased from musaji adam and sons Karachi (imports@science-ware.com). The antibacterial activity of oenothera biennis seed extract against staphylococcus aureus was tested by deep well broth microdilution and disc diffusion method. Different concentrations of stock solutions (100μg/10μl to 500μg/10μl of DMSO) were used to test antimicrobial effect to establish dose response relationship. Results: Results were measured and compared according to Clinical and Laboratory Standard Institute. Oenothera biennis seed extract inhibited growth of methicillin sensitive and methicillin resistant staphylococcus aureus isolate from laboratory as well as ATCC strains with minimum inhibitory concentration 530μg/10μl solvent. Whereas other concentrations 50 μg/10μl ,100 μg/10μl ,150 μg/10μl ,200 μg/10μl ,250 μg/10μl ,300 μg/10μl ,350 μg/10μl ,400 μg/10μl ,450 μg/10μl and 500 μg/10μl had no effect at all. Conclusion: Oenothera biennis extract inhibits growth of staphylococcus aureus at concentration of 530μg remarkably. This can inhibit both MSSA &amp; MRSA already proved in our study. This could be beneficial as an alternate medicine. However, further research is needed to be conducted for animal study. Key words: Oenothera biennis, ethanolic extract, Methicillin sensitive, Methicillin Resistant Staphylococcus aureus, MSSA, MRSA.

Occurrence of Multidrug-Resistant Staphylococcus aureus among Humans, Rodents, Chickens, and Household Soils in Karatu, Northern Tanzania.

We conducted this study to investigate the isolation frequency and phenotypic antibiotic resistance pattern of Staphylococcus aureus isolated from rodents, chickens, humans, and household soils. Specimens were plated onto mannitol salt agar (Oxoid, Basingstoke, UK) and incubated aerobically at 37 °C for 24 h. Presumptive colonies of S. aureus were subjected to Gram staining, as well as catalase, deoxyribonuclease (DNAse), and coagulase tests for identification. Antibiotic susceptibility testing was performed by using the Kirby–Bauer disc diffusion method on Mueller–Hinton agar (Oxoid, Basingstoke, UK). The antibiotics tested were tetracycline (30 μg), erythromycin (15 μg), gentamicin (10 μg), ciprofloxacin (5 μg), clindamycin (2 μg), and amoxicillin-clavulanate (20 μg/10 μg). The S. aureus strain American Type Culture Collection (ATCC) 25,923 was used as the standard organism. We found that 483 out of 956 (50.2%) samples were positive for S. aureus. The isolation frequencies varied significantly between samples sources, being 52.1%, 66.5%, 74.3%, and 24.5%, respectively, in chickens, humans, rodents, and soil samples (p < 0.001). S. aureus isolates had high resistance against clindamycin (51.0%), erythromycin (50.9%), and tetracycline (62.5%). The overall prevalence of multidrug-resistant (MDR) S. aureus isolates was 30.2%, with 8.7% resistant to at least four different classes of antibiotics.

In vitro antimicrobial activity of cold atmospheric microwave plasma against bacteria causing canine skin and ear infections.

Cold atmospheric plasma (CAP) is a new generation medical therapeutic option for bacterial infections. CAP causes physical cell wall rupture and DNA damage, therefore making it highly useful in the treatment of various conditions such as skin infections. The antimicrobial activity of cold atmospheric microwave plasma (CAMP) against major strains in canine skin infections was tested and the difference in antimicrobial activity between the antibiotic-resistant and antibiotic-susceptible strains of Staphylococcus pseudintermedius was evaluated. American Type Culture Collection (ATCC) strains (Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli) and clinical isolates identified as methicillin-resistant S.pseudintermedius (n=27) and methicillin-susceptible S.pseudintermedius (n=13) were exposed to CAMP for 10s, 30s and 60s. Afterwards, the bacterial survival rate was confirmed. Gram-negative bacteria (P.aeruginosa and E.coli) were more susceptible than Gram-positive bacteria (S.aureus and S.pseudintermedius) for the same duration of CAMP exposure. Only the Gram-negative bacteria were completely killed after 60s exposure. In S.pseudintermedius isolates, CAMP exposure had similar antibacterial effects regardless of antibiotic resistance. CAMP has sufficient antimicrobial activity against major bacterial strains that cause pyoderma and otitis externa in dogs, and may be an alternative therapeutic option for S.pseudintermedius skin infections, for which antibiotics often are ineffective because of antimicrobial resistance in clinical veterinary medicine.

Antimicrobial susceptibilities and comparative whole genome analysis of two isolates of the probiotic bacterium Lactiplantibacillus plantarum, strain ATCC 202195

A synbiotic containing Lactiplantibacillus plantarum [American Type Culture Collection (ATCC) strain identifier 202195] and fructooligosaccharide was reported to reduce the risk of sepsis in young infants in rural India. Here, the whole genome of two isolates of L. plantarum ATCC 202195, which were deposited to the ATCC approximately 20 years apart, were sequenced and analyzed to verify their taxonomic and strain-level identities, identify potential antimicrobial resistant genes and virulence factors, and identify genetic characteristics that may explain the observed clinical effects of L. plantarum ATCC 202195. Minimum inhibitory concentrations for selected antimicrobial agents were determined using broth dilution and gradient strip diffusion techniques. The two L. plantarum ATCC 202195 isolates were genetically identical with only three high-quality single nucleotides polymorphisms identified, and with an average nucleotide identity of 99.99%. In contrast to previously published reports, this study determined that each isolate contained two putative plasmids. No concerning acquired or transferable antimicrobial resistance genes or virulence factors were identified. Both isolates were sensitive to several clinically important antibiotics including penicillin, ampicillin and gentamicin, but resistant to vancomycin. Genes involved in stress response, cellular adhesion, carbohydrate metabolism and vitamin biosynthesis are consistent with features of probiotic organisms.

Quantification of biofilm produced by clinical, environment and hands’ isolates Klebsiella species using colorimetric and classical methods

Some species of Klebsiella, such as Klebsiella pneumoniae and Klebsiella oxytoca, are important nosocomial pathogens frequently involved in outbreaks in Neonatal Intensive Care Units (NICU) and have the ability to form a biofilm. This study aims to evaluate the biofilm production of K. pneumoniae and K. oxytoca isolates collected from the hands of health professionals, neonates' blood and the environment of a Brazilian NICU, using three colorimetric methods and a classical method of counting the colony-forming units and compare the analysis among these techniques. The biofilm formation was carried out by the microplate technique, using three colorimetric assays: crystal violet, safranin and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl) -5 [(phenylamino) arbonyl] - 2H-tetrazolium hydroxide (XTT). Also, colony-forming units were determined. Twenty-eight isolates of K. pneumoniae were collected from the blood, hands and environment and five of K. oxytoca from the hands and environment. All of them were strong biofilm producers, but K. pneumoniae isolates produced more biofilm than K. oxytoca when compared to the American Type Culture Collection (ATCC) strains used as positive controls. The number of viable cells in the biofilm produced by K. pneumoniae isolated from blood was significantly higher than in the control sample. Regarding the three colorimetric tests used in the study, the violet crystal obtained a higher absorbance average. The use of crystal-violet and XTT in the evaluation of biofilm in vitro make possible a complete analysis, since that it can quantify the total biomass (including the extracellular matrix) and evaluate the metabolic activity. In conclusion, this study identified isolates of K. pneumoniae and K. oxytoca that produce biofilms in the NICU and the bloodstream of neonates. This fact deserves attention since these patients are immunocompromised. The best methods will be chosen to answer research questions by always adopting more than one method so that more than one parameter or component of the biofilm is analyzed.

Essential Oil Analysis and Antimicrobial Evaluation of Three Aromatic Plant Species Growing in Saudi Arabia.

Arabian flora is a rich source of bioactive compounds. In this study, we investigated three aromatic plant species with the aim of finding valuable sources of antimicrobial agents against common pathogenic microorganisms. We focused especially on microorganisms, which cause outbreaks of infectious disease during mass gatherings and pilgrimages season in Saudi Arabia. The essential oils of three aromatic plant species were hydrodistilled from flowering aerial parts of Lavandula pubescens Decne. and Pulicaria incisa subsp. candolleana E.Gamal-Eldin, and from leaves, stems, ripe and unripe fruits of Juniperus procera Hochst. Ex Endl. They were subsequently analyzed by gas chromatography-mass spectrometry (GC-MS). The main constituents of L. pubescens were found to be carvacrol (55.7%), methyl carvacrol (13.4%), and β-bisabolene (9.1%). P. incisa subsp. Candolleana essential oil was rich in linalool (33.0%), chrysanthenone (10.3%), eugenol (8.9%), and cis-chrysanthenol (8.0%); the major components of J. procera essential oil were α-pinene (31.3–62.5%) and δ-3-carene (7.3–30.3%). These essential oils were tested against thirteen American Type Culture Collection (ATCC) strains of Gram-positive and Gram-negative bacteria using the agar diffusion assay. The only effective essential oil was that of L. pubescens and the most sensitive strains were Acinetobacter baumannii, Salmonella typhimurium, Shigella sonnei, Enterococcus faecalis and Staphylococcus epidermidis. Carvacrol, the major constituent of L. pubescens, was tested on these strains and was compared with vancomycin, amikacin, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays of L. pubescens essential oil and carvacrol revealed that Gram-negative strains were more susceptible than the Gram-positive ones.

Antibacterial activity of melatonin against prime periodontal pathogens: An in vitro study

Aim: Accumulated data make it clear that by introducing large amount of antibiotics into the ecosystem, we have provided an environment conducive to antibiotic resistance and periodontal microbes are no different. Therefore, in the quest of finding a suitable drug as an alternate to antibiotic, we investigated the antibacterial activity of melatonin against predominantly Gram-negative periodontal pathogens in vitro. Melatonin with varied functions has driven its usage enormously; therefore, identifying its action against periodontal pathogens has driven this laboratory investigation. Materials and Methods: American type culture collection (ATCC) strains of Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans were used to determine minimum inhibitory and bactericidal concentrations (MIC and MBC) of melatonin using macro broth dilution method. MIC values were determined at 24, 48, and 72 h and sensitive MIC values were sub-cultured to determine MBC value at 24 h. Qualitative data were obtained and it was recorded as “sensitive” or “resistant” at respective concentrations. Results: When tested over a dilution range of 0.2–100 µg/mL, melatonin significantly inhibited microbial growth. At 48 h, the MIC value against A. actinomycetemcomitans, P. gingivalis, and F. nucleatum was 6.25, 0.8, and ≤0.2 µg/mL, respectively. The MBC value determined at 24 h demonstrated significant bactericidal activity against the pathogens. Conclusion: Melatonin exhibited bactericidal activity against prime periodontal pathogens even at low concentrations in comparison to previously documented evidences suggesting greater potency of the drug. Hence, renewed effort to find and develop new class of drug which can inhibit periodontal pathogens, rather than just improvements on already-existing drugs can potentially prevent the development of resistant strains in periodontal microenvironment.

Assessment of carbapenem-resistant Enterobacteriaceae-plate formula and quality control procedure.

AimsTo assess a cost‐effective in‐house selective plate formula for actively screening carbapenem‐resistant Enterobacteriaceae (CRE).Methodology and resultsThe in‐house formula included CHROMagarTM Orientation, meropenem, and ingredients present in the Mac‐Conkey formula, such as bile salts and crystal violet (pH 6.9‐7.2). American Type Culture Collection strains and 200 clinical strains were used to validate the plate formula. The CRE plates had a sensitivity of 97.4% and a specificity of 98.8% with ATCC andor clinical strains used in the quality control procedure. A point prevalence survey among the 18 inpatients at Viet‐Tiep hospital ICU using fecal swabs plated at the in‐house agar plate showed a CRE prevalence of 44.4%.ConclusionThe in‐house plate had high sensitivity and specificity, particularly for Escherichia coli and the KESC group (Klebsiella spp., Enterobacter spp., Serratia marscescens, and Citrobacter spp.), and it may be widely applied as an alternative to other ready‐to‐use commercial plates.Significance and impact of the studyThe formula developed in the present study may facilitate the early detection and isolation of CRE and decrease transmission, particularly in low‐ and middle‐income countries with a high rate of CRE colonization and limited access to ready‐to‐use commercial plates.

Antifungal Activities of Ziziphus mauritiana against Candida albicans: In Vitro Study

Medicinal plants have been discovered and used in traditional medicine and pharmaceutical industries since centuries. In the current study, Ziziphus mauritiana leaves was used as it is rich with many biological active compounds such as flavonoids, polyphenols, sapronins and tanins. Previous studies reported the antibacterial and antifungal effects of Z. mauritiana towards various microorganisms. However, the antifungal activities of Z. mauritiana methanol extracts on Candida albicans (Clinical and American Type Culture Collection Strains) have not been discovered extensively.Objectives: Therefore, the aim of the current study is to investigate the antifungal activity of Z. mauritiana leaves methanol extracts against C. albicans ATCC strain and clinical isolate (from oral cancer patient).Methods: Antifungal susceptibility test (AST) was performed using disc diffusion, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) to determine the antifungal activity of methanol leaves extract of Ziziphus mauritiana against C. albicans ATCC and clinical isolates.Results: The results obtained showed that there is no zone of inhibition seen from disk diffusion test for both strains. However, the minimal inhibitory and minimal fungicidal concentration showed that Ziziphus mauritiana methanol extracts was able to inhibit C. albicans clinical isolate but not ATCC strain at 500mg/mL.Conclusion: The finding of this study suggests that that Ziziphus mauritiana leaves methanol extract showed promising results against Candida albicans. Thus, it can be used as a source for functional ingredients for pharmaceutical drug industries in-order to reduce or inhibit oral fungal infection.

γ-Glutamyltransferase as a Novel Virulence Factor of Acinetobacter baumannii Inducing Alveolar Wall Destruction and Renal Damage in Systemic Disease

A thorough understanding of Acinetobacter baumannii pathogenicity is the key to identifying novel drug targets. In the current study, we characterize the γ-glutamyltransferase enzyme (GGT) as a novel virulence factor. A GGT assay showed that the enzyme is secreted via the type II secretion system and results in higher extracellular activity for the hypervirulent AB5075 than the laboratory-adapted strain American Type Culture Collection 17978. Enzyme-linked immunosorbent assay revealed that the former secretes larger amounts of GGT, and a rifampicin messenger RNA stability study showed that one reason for this could be the longer AB5075 ggt transcript half-life. Infection models confirmed that GGT is required for the virulence of A. baumannii. Finally, we show that clinical isolates with significantly higher extracellular GGT activity resulted in more severe infections, and assay of immune response and tissue damage markers confirm this correlation. The current findings establish for the first time the role of the GGT in the pathogenicity of A. baumannii.

Cytotoxicity and Antimycobacterial Properties of Pyrrolo[1,2-a]quinoline Derivatives: Molecular Target Identification and Molecular Docking Studies.

A series of ethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-3-carboxylates 4a–f and dimethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylates 4g–k have been synthesized and evaluated for their anti-tubercular (TB) activities against H37Rv (American Type Culture Collection (ATCC) strain 25177) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis by resazurin microplate assay (REMA). Molecular target identification for these compounds was also carried out by a computational approach. All test compounds exhibited anti-tuberculosis (TB) activity in the range of 8–128 µg/mL against H37Rv. The test compound dimethyl-1-(4-fluorobenzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylate 4j emerged as the most promising anti-TB agent against H37Rv and multidrug-resistant strains of Mycobacterium tuberculosis at 8 and 16 µg/mL, respectively. In silico evaluation of pharmacokinetic properties indicated overall drug-likeness for most of the compounds. Docking studies were also carried out to investigate the binding affinities as well as interactions of these compounds with the target proteins.