Antibacterial potential of essential oils against planktonic and sessile cells of Escherichia coli isolated from diarrhea cases in swine

Escherichia coli is a pathogen associated with infections in piglets in the post-weaning phase, its pathogenicity is related to the animal's susceptibility to bacterial enterotoxins. The objective of the present study was to determine the EOs activity against E. coli strain, in the form planktonic and sessile. Although the Disc-Diffusion tests to determine the Minimum Inhibitory Concentration, do not fully corroborate with the other analyzes of this study, it was noticed bacteria inhibition. The EOs were prepared at 0.4%, 0.8% and 1.0% for tests. The tested EOs were effective against E. coli planktonic cells (p<0.05). As for the sessile cells, the most significant result was inhibition and 100% sessile cells at the concentration of 1.0% of Cymbopogon citratus EO. Although there was resistance in some treatments, the tested EOs demonstrated inhibition capacity, constituting promising alternatives for the control of E. coli, especially of planktonic cells.

Screening of the antioxidant and antibacterial effects of extracted essential oils from Thunbergia coccinea, Acacia polyacantha, Polygonum micrpcephallum, Abies spectabilis and Clerodendrum colebrookianum

During the previous few decades, it has been seen that there is a rapid emergence of pathogens resistant to multiple antibiotics. This has now become a global crisis. Some unexplored or less explored plants also provide some antibacterial, bactericidal and antioxidant properties. The antibacterial, bactericidal effects of extracted essential oils (EEOs) of Thunbergia coccinea, Acacia polyacantha, Polygonum micrpcephallum, Abies spectabilis and Clerodendrum colebrookianum was tested in comparison with standard antibiotics. The methods chosen were disc diffusion and deduction of minimum inhibitory concentration (MIC) by microbroth dilution assays of the EEOs against the bacterial strains.The antioxidant activity was found out utilizing DPPH free radical scavenging assay, MDA, Hydrogen peroxide radical inhibition assay and Superoxide radical inhibition assay (O 2 -). Some commonly used standard antibiotics (metronidazole, amoxicillin, clarithromycin, rifampicin, clindamycin and oxacillin,) were utilized to compare the EEO antibacterial action. Clerodendrum colebrookianum (85.17 ± 3.06 µg MDA/g extract) had a reasonable MDA. Acacia polyacantha in MIC had values of 3.86 ± 0.25 to 6.20 ± 0.16. Polygonum micrpcephallum had excessive H2O2 (48.27 ± 2.4 5%). The antibacterial actions determined by the paper disc‑diffusion technique of the EEO extracted from these plants showed that most had some antibacterial actions. Also, it was seen that the bactericidal action of the EEO extracted from E. alba was most potent against S. pyogenes (4.06 ± 0.15). The extract of the plant at varying concentrations (20, 40, 60, 80 and100 mg/mL) demonstrated noteworthy (P< 0.001) anthelmintic action in an effective change when the dose was adjusted. In conclusion, most of the tested plants contain a medicinal value, which can be utilized in the future to supplement artificial medicines and cure emerging diseases that create havoc for mankind.

Antibacterial Profile in vitro and in vivo of New 1,4-Naphthoquinones Tethered to 1,2,3-1H-Triazoles against the Planktonic Growth of Streptococcus mutans

The cariogenic processes are mainly caused by the bacterium Streptococcus mutans (S. mutans) and consist of the demineralization of the tooth that occurs when the acid production overcomes the natural repair or if a problem occurs in the last one. In this work, we performed the synthesis of twenty-one 1,4-naphthoquinones tethered to 1,2,3-1H-triazoles (8a-8k and 9a-9j), antibacterial evaluation against the S. mutans in vitro and the acute toxicity of the better ones in vivo. We observed strong inhibition results in the disc diffusion test ranging, the halos of inhibitions, from 18.66 (± 0.57) to 29 (± 2.64) mm, and good values in the minimum inhibitory concentration (5 to 50 μg), for the compounds 9e, 9h, 9i and 9j. Furthermore, they do not have a cytotoxic effect at the concentrations tested. Besides that, in the in vivo test, they show some slight alteration in the histopathological analyses and the biochemistry. Thus, we found four potential candidates to become instruments for the treatment of cavities.

TLC-contact bioautography and disc diffusion method for investigation of the antibacterial activity of Melastoma malabathricum L. leaves

The emergence of multi-resistant strains of bacteria reinforces the need to discover new antibacterial agents that are able to combat resistant microorganisms. Medicinal plants are a valuable natural source of bioactive substances against various infectious diseases. Melastoma malabathricum L. is an important herb that is traditionally used to treat several ailments associated with microbial infection diseases such as wounds, diarrhea, dysentery, and toothache. This study investigated extracts of M. malabathricum L. for antibacterial properties against Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA). Disc diffusion and TLC-contact bioautography techniques were employed to examine antibacterial properties of n-hexane, ethyl acetate, and ethanol extracts with observations of diameter inhibition zones and Rf values. Investigation of active compounds in TLC-bioautography used several reagents including citroboric, cerium (IV) sulfate and 2,2-diphenyl-1-picrylhydrazyl (DPPH), continued by identification of chromatogram profiles through densitometry analysis. The three extracts showed good inhibition against bacterial strains with diameter inhibition zones in the range of 8.0 – 14.0 mm with a number of active spots on TLC-contact bioautography for each extract. This plant may serve as useful source of antibacterial agents for resistant microorganisms and further investigation is needed of its bioactive pure compounds as well as their particular therapeutic potentials and applications.

Synthesis, Structural Analysis and Antimicrobial Screening of Mn(II) Complexes of Schiff Bases

Mn(II) complexes of Schiff bases 4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(pyridin-2-yl)benzenesulfonamide (HL2) and 4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(pyrimidin-2- yl)benzenesulfonamide (HL3) were synthesized. The Schiff bases HL2 and HL3 and their complexes were characterized by analytical, conductance, magnetic susceptibility measurements, infrared, ultraviolet-visible, thermal analysis, and EI mass techniques. The spectral data of the complexes have revealed the bidentate complexing nature of the Schiff base ligand through phenoxide ion and azomethine nitrogen atoms. The antibacterial activities of complexes were tested against gram-positive bacterial species Pseudomonas aeruginosa (NCIM 2036) and fungal species Aspergillus niger (NCIM 105) and Mucor sp. (NCIM 108) by disc diffusion method. Keywords: Schiff bases; Mn(II) complex; antibacterial; antifungal. Resumen. Los complejos de Mn(II) de las bases de Schiff 4-((3-etoxi-2-hidroxibencilideno)amino)-N-(piridin-2-il)bencenosulfonamida (HL2) y 4-((3-etoxi-2-hidroxibencilideno)amino)-N-(pirimidin-2- il)bencenosulfonamida (HL3) fueron sintetizados. Las bases de Schiff HL2 and HL3 y sus complejos fueron caracterizados por métodos analíticos, conductancia, susceptibilidad magnética, espectroscopia infrarroja y UV-vis, termogravimetría, y espectrometría de masas por impacto enectrónico. Los datos espectroscópicos obtenidos para los complejos corroboraron la coordinación bidentada de los ligantes de base de Schiff a través del ion fenóxido y el átomo de nitrógeno del grupo azometino. La actividad antibacterial de los complejos se evaluó contra cepas bacterianas gram-positivas Pseudomonas aeruginosa (NCIM 2036) y contra especies fúngicas Aspergillus niger (NCIM 105) y Mucor sp. (NCIM 108) utilizando el método de difusión en disco.

Uji Aktivitas Antibakteri Ekstrak Etanol Daun Pare (Momordica charantia L.) Terhadap Bakteri Staphylococcus aureus ATCC 25923

Bitter gourd as a traditional medicine has a chemical content in its leaves that are useful as antimicrobials and as antioxidants. According to research by Tessa Undap, 2017 shows that bitter melon leaves have an inhibitory power against the growth of Staphylococcus aureus bacteria by inhibiting protein synthesis. The purpose of this study was to determine the antibacterial activity of bitter melon leaf extract (Momordica charantia L.). The research method used in this study is the disc diffusion method. Data was collected by measuring the diameter of the clear zone formed in each treatment. The antibacterial results showed that the 9% extract concentration had the highest inhibitory power.Keywords: Antibacterial, Pare Leaf Extract, Granules, Staphylococcus aureus. AbstrakTanaman pare sebagai obat tradisional memiliki kandungan kimia dalam daunnya yang bermanfaat sebagai antimikroba dan sebagai antioksidan. Menurut penelitian oleh Tessa Undap, 2017 menunjukkan bahwa daun pare mempunyai daya hambat terhadap pertumbuhan bakteri Staphylococcus aureus dengan cara menghambat sintesis protein. Adanya kandungan flavonoid dalam daun pare dapat menghambat pertumbuhan bakteri Staphylococcus aureus yang dapat mengkoagulasi protein pada sel bakteri. Tujuan dari penelitian ini yaitu untuk mengetahui aktivitas antibakteri yang terkandung dalam ekstrak daun pare (Momordica charantia L.). Metode penelitian yang digunakan dalam penelitian ini yaitu metode difusi cakram disk. Pengumpulan data dilakukan dengan cara mengukur diameter zona bening yang terbentuk pada setiap perlakuan. Hasil antibakteri yaitu menunjukkan bahwa konsentrasi ekstrak 9% mempunyai daya hambat paling tinggi.Kata kunci: Antibakteri, Ekstrak Daun Pare, Granul, Staphylococcus aureus.

CRUDE EXTRACTS OF MAGNOLIA ALBA FLOWERS USING N-HEXANE AND METHANOL SOLVENTS AND THEIR ANTI-ACNE POTENTIAL

This study aimed to test the antibacterial activity of n-hexane and methanol extracts of white cempaka flowers (Magnolia alba) against Propionibacterium acnes bacteria. The extract was obtained by using the maceration method for 72 hours. Each extract was tested for its antibacterial properties using the disc diffusion method with the variant concentration of the extract used was 0.05%; 2%; 4%; 6%; and 8%. The results showed that the methanol extract had a higher inhibition zone than the n-hexane extract. In n-hexane extract, the lowest concentration of 0.05% showed an inhibition zone of 6.6 mm and the highest concentration of 8% had an inhibition zone of 9.6 mm. Whereas in methanol extract, the inhibition zone obtained was 7.3 mm at a low concentration of 0.05%, but at the highest concentration of 8% the inhibition zone obtained was 11.6 mm. The effect of extract concentration on the diameter of the inhibition zone formed is very significant (directly proportional), where the higher the concentration used, the larger the diameter of the inhibition zone produced. Antibacterial testing for both extracts showed a weak (< 10 mm) to moderate (> 10 mm) bacterial inhibition, which was similar with the inhibition zone obtained from the positive control (11-11.3 mm; moderate bacterial inhibition).

Minimum inhibitory concentration of Ceftazidime-Avibactam against Clinical isolates of XDR Salmonella enterica Serovar Typhi

Background: Typhoid fever is a major healthcare problem in low and middle-income countries. The emergence of extensively drug-resistant (XDR) typhoid has further narrowed down the way to already limited therapeutic options. WHO has listed S.Typhi amongst the priority pathogens against which new treatment options should be discovered.Objective: To determine In-vitro activity of Ceftazidime-avibactam against clinical isolates of XDR S.Typhi.Study design: This is a cross-sectional studyPlace and duration of the study: The Department of Microbiology, University of health sciences, Lahore from January to June 2021.Methodology: Antimicrobial susceptibility was performed initially by Kirby Bauer disc diffusion method for 150 of XDR Salmonella enterica Serovar Typhi and MICs of all the recommended antibiotics was determined by VITEK 2 (bioMérieux) fully automated system using Clinical Laboratory Standard Institute (CLSI) 2021 guidelines. MICs by the E-test method were determined for Ceftazidime-avibactam and Azithromycin only. All tests were done in duplicate.Results: All 150 (100%) isolates were sensitive to Ceftazidime-avibactam by disc diffusion and E-test methods. Out of 150 isolates 8(5.3%) were having high MICs against Azithromycin.Conclusions: Ceftazidime-avibactam can be used wisely to treat ESBL producing XDR typhoid fever cases especially in countries like Pakistan where Typhoid fever is endemic and majority of isolates are extensively drug resistant.

INSIGHT INTO ANTIMICROBIC EVALUATION TECHNIQUES AND THEIR ROLE IN BETTER ASSESSMENT OF ANTIMICROBIC AGENTS: A REVIEW

At present, researchers have a keen interest in creating advanced antimicrobic agents to overcome microbial resistance from various new sources either from plants or microbes. For this, robust attention has been given to the advancement in the rapid antimicrobic assessment strategies and methods to develop antimicrobic agents. Some of the antimicrobic techniques such as well diffusion using broth and agar and disc diffusion are more prominent in assaying antimicrobial testing while techniques such as bioluminescence, flow cytofluorometry methods are less used due to specific equipment’s, high calibration and evaluation processes. Thus, the information of precise antimicrobial techniques is must to the new researchers for antimicrobic testing. In this review article, various antimicrobic techniques with their advantages and limitations are being reported which are currently being carried out for antimicrobial testing.