Antibiotic Resistance of Heterotrophic Bacteria Isolated from Various Habitats of the Litoral Area of Lake Baikal

This is the first time the data on the antibiotic resistance of heterotrophic bacteria were obtained. These bacteria were isolated from fouling of stone substrates and also from «healthy» and «diseased» sponges of Lake Baikal. We have analysed 377 strains for the resistance to 11 antimicrobial agents. 133 of them were isolated from the water column, 277 from stone fouling, 17 from «healthy» sponges, and 20 from «diseased» sponges of Lake Baikal. We have revealed 9 sensitive strains and 36 strains resistant to all antibiotics. A high percentage of bacterial strains from both plankton (34–82 %) and periphyton (23–94 %) are resistant to a number of broad-spectrum antibiotics. At the same time, they have different sensitivity to azithromycin, vancomycin, tetracycline, and meropenem. The strains isolated from periphyton showed the most effective antimicrobial activity to azithromycin, tetracycline and meroperem; those isolated from water showed the most effective antimicrobial activity to meroperem. The strains sensitive to antibiotics (18–71 %) prevail in the microbial community of «healthy» sponges. At the same time, the microbial community of «diseased» sponges has a larger share of sensitive strains, which accounts for 30–75 %. The proportion of resistant strains with gram-negative cell wall is higher for most antibiotics compared to the gram-positive bacteria.

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Genome Analysis of Two Bacterial Strains Isolated from Diseased Freshwater Sponge Reveals the Probable Cause of Its Joint Domination in Microbial Community

10.20944/preprints202009.0144.v1 ◽

2020 ◽

Author(s):

Ivan Petrushin ◽

Sergei Belikov ◽

Lubov Chernogor

Keyword(s):

Microbial Community ◽

Lake Baikal ◽

Freshwater Ecosystems ◽

Freshwater Sponge ◽

Type Vi Secretion System ◽

Bacterial Strains ◽

Freshwater Sponges ◽

Gram Positive Bacteria ◽

Exopolysaccharide Biosynthesis ◽

Relationship Of

Endemic freshwater sponges (Demosponges, Lubomirskiidae) dominate in Lake Baikal and are multicellular filter-feeding animals represent a complex consortium of many species of eukaryotes and prokaryotes. In recent years, mass disease and death of the L. baicalensis have been an urgent problem of Lake Baikal. The etiology and ecology of these events remain unknown. Bacteria in microbiomes of diseased sponges of the families Flavobacteriaceae and Oxalobacteraceae were dominant. Both species are opportunistic pathogens common for freshwater ecosystems. The aim of our study is to analyze the genomes of strains Janthinobacterium sp. SLB01 and Flavobacterium sp. SLB02, isolated from diseased sponges to identify the reasons for their joint dominance. The first one attacks the other cells using type VI secretion system, suppress gram-positive bacteria with violacein pigment and regulate its own activity via quorum sensing. It makes the floc and strong biofilm by exopolysaccharide biosynthesis and PEP‐CTERM proteins expression. The second one utilizes the fragments of cell walls produced of polysaccharides. Named two strains have noticeable difference in carbohydrates acquisition. We described the possible way of joint occupation of ecological niche into freshwater sponge microbial community. This study expands understanding about symbiotic relationship of microorganisms with freshwater Baikal sponges.

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Ultraviolet Radiation and Salinity-Induced Physiological Changes and Scytonemin Induction in Cyanobacteria Isolated from Diverse Habitats

Biointerface Research in Applied Chemistry ◽

10.33263/briac123.35903606 ◽

2021 ◽

Vol 12 (3) ◽

pp. 3590-3606

Keyword(s):

Antimicrobial Activity ◽

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Antimicrobial Agents ◽

Free Ligand ◽

The Novel ◽

Bacterial Strains ◽

Resistant Strains ◽

Antimicrobial And Antifungal Activity

A novel series of transition metal (II) complexes (5a-h) were conveniently synthesized via reaction of important transition metals (Co, Cu, Zn, Ni) with (E)-N-(4-methylbenzylidene)-2-((Z)-(4-methylbenzylidene)amino)benzamide Schiff base (3) which was previously synthesized by reacting 2- aminobenzohydrazide (1) with 4-methylbenzaldehyde (2). The synthesized metal complexes' structure was elucidated by IR, NMR, mass, and elemental analysis. Additionally, we also evaluated the antioxidant, antimicrobial and antifungal activity of the synthesized metal complexes. The bioassay of the novel transition metal complexes envisioned that compounds5eand5c showed better antimicrobial activity than the free ligand, and compounds5g and 5a showed good activity against most bacterial strains. On the other hand, hydrated metal complexes 5b, 5d, 5f, and 5h showed moderate to good antimicrobial activity. In comparison with ascorbic acid, most of the metal complexes showed moderate to good antioxidant activity. The current bioassay was investigated and proved that the compounds 5e and 5c as antimicrobial agents act on highly resistant strains of microbes.

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Graphene Matrices as Carriers for Metal Ions against Antibiotic Susceptible and Resistant Bacterial Pathogens

Coatings ◽

10.3390/coatings11030352 ◽

2021 ◽

Vol 11 (3) ◽

pp. 352

Author(s):

Anthony J. Slate ◽

Nathalie Karaky ◽

Grace S. Crowther ◽

Jonathan A. Butler ◽

Craig E. Banks ◽

...

Keyword(s):

Antimicrobial Activity ◽

Metal Ions ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Therapeutic Option ◽

Bacterial Strains ◽

Graphene Foam ◽

Coating Method ◽

Resistant Strains ◽

Specific Metal

Due to the ever-increasing burden of antimicrobial-resistant (AMR) bacteria, the development of novel antimicrobial agents and biomaterials to act as carriers and/or potentiate antimicrobial activity is essential. This study assessed the antimicrobial efficacy of the following ionic metals, silver, gold, palladium, platinum, zinc, and gallium alone and in combination with graphene matrices (which were coated via a drop casting coating method). The graphene foam was utilized as a carrier for the ionic metals against both, antibiotic susceptible and resistant bacterial strains of Acinetobacter baumannii,Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Ionic gold, palladium and platinum demonstrated the greatest antimicrobial activity against the susceptible and resistant strains. Scanning electron microscopy (SEM) visualized cellular ultrastructure damage, when the bacteria were incubated upon the graphene foam alone. This study suggests that specific metal ions applied in combination with graphene foam could present a potential therapeutic option to treat AMR bacterial infections. The application of the graphene foam as a potential carrier could promote antimicrobial activity, provide a sustained release approach and reduce possible resistance acquisition. In light of this study, the graphene foam and ionic metal combinations could potentially be further developed as part of a wound dressing.

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Isolation of a Variant of Subtilosin A with Hemolytic Activity

Journal of Bacteriology ◽

10.1128/jb.00541-09 ◽

2009 ◽

Vol 191 (18) ◽

pp. 5690-5696 ◽

Cited By ~ 40

Author(s):

Tai Huang ◽

Hao Geng ◽

Venugopal R. Miyyapuram ◽

Clarissa S. Sit ◽

John C. Vederas ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antibacterial Activity ◽

Bacillus Subtilis ◽

Hemolytic Activity ◽

Antimicrobial Agents ◽

Cell Envelope ◽

Bacterial Strains ◽

Gram Positive Bacteria ◽

Altered Form ◽

Resistant Mutation

ABSTRACT Bacillus subtilis produces an anionic bacteriocin called subtilosin A that possesses antibacterial activity against certain gram-positive bacteria. In this study, we uncovered a hemolytic mutant of B. subtilis that produces an altered form of subtilosin A. The mutant bacteriocin, named subtilosin A1, has a replacement of threonine at position 6 with isoleucine. In addition to the hemolytic activity, subtilosin A1 was found to exhibit enhanced antimicrobial activity against specific bacterial strains. The B. subtilis albB mutant that does not produce a putative immunity peptide was more sensitive to both subtilosin A and subtilosin A1. A spontaneous suppressor mutation of albB that restored resistance to subtilosin A and subtilosin A1 was obtained. The sbr (subtilosin resistance) mutation conferring the resistance is not linked to the sboA-alb locus. The sbr mutation does not increase the resistance of B. subtilis to other cell envelope-targeted antimicrobial agents, indicating that the mutation specifically confers the resistance to subtilosins. The findings suggest possible bioengineering approaches for obtaining anionic bacteriocins with enhanced and/or altered bactericidal activity. Furthermore, future identification of the subtilosin-resistant mutation could provide insights into the mechanism of subtilosin A activity.

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Analysis of the Antibiotic Resistance of Bacteria Isolated from Various Ecological Niches of Lake Baikal Ecosystem

Известия Байкальского государственного университета ◽

10.17150/2500-2759.2021.31(2).241-247 ◽

2021 ◽

Vol 31 (2) ◽

pp. 241-247

Author(s):

Elena Verkhozina ◽

Valentina Verkhozina ◽

Olga Belykh

Keyword(s):

Antibiotic Resistance ◽

Lake Baikal ◽

Bacterial Resistance ◽

Dispersion Analysis ◽

Ecological Niches ◽

Bacterial Strains ◽

Sea Bottom ◽

Highly Sensitive ◽

Almost All ◽

First Time

The article presents the results of monitoring studies of bacterial strains on antibiotic resistance held from 1995 to 2015. Samples were selected from various ecological niches of the Lake Baikal ecosystem. The bacteria was analyzed for sensitivity and resistance to 14 antibiotics. It was revealed that bacteria resistant to many antibiotics were isolated from the lake's lithoral. For the first time it has been established that when analyzing a large amount of received data, it is advisable to use variance and correlation methods of analysis. A dispersion analysis of bacterial resistance to antibiotics grouped by the factor of belonging to a certain month of sampling has found that in different months of the year, average resistance is reliably different (P_value = 0,003 < α), i.e. seasonal dynamics are observed. Isolated strains are resistant to a range of broad-spectrum antibiotics, especially tetracycline and ampicillin. The most effective antimicrobial action is noted for pefloxacin, cephaloxima, gentamicin, cephalozolin. According to the cluster analysis, antibiotic-resistant strains are cross-resistant to many antibiotics. Bacteria isolated from the pelagilyan ecosystems of Lake Baikal and deep-sea bottom sediments are highly sensitive to almost all antibiotics.

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SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

Journal of Biomedical and Pharmaceutical Research ◽

10.32553/jbpr.v7i6.561 ◽

2018 ◽

Vol 7 (6) ◽

Author(s):

Singh Gurvinder ◽

Singh Prabhsimran ◽

Dhawan R. K.

Keyword(s):

Antimicrobial Activity ◽

Spectral Analysis ◽

Schiff Bases ◽

Antimicrobial Agents ◽

Biological Evaluation ◽

Fungal Strain ◽

Bacterial Strains ◽

Standard Drug ◽

Gram Negative ◽

E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

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The Chemistry Of Antibiofilm Phytocompounds.

Mini-Reviews in Medicinal Chemistry ◽

10.2174/1389557520666200807135243 ◽

2020 ◽

Vol 20 ◽

Author(s):

Dibyajit Lahiri ◽

Moupriya Nag ◽

Sayantani Garai ◽

Rina Rani Ray

Keyword(s):

Antimicrobial Activity ◽

Antibiotic Resistance ◽

Antibiotic Therapy ◽

Antimicrobial Agents ◽

Chemical Nature ◽

Rapid Development ◽

Wide Spread ◽

Chronic Infections ◽

Therapeutic Uses

: Phytocompounds are long known for their therapeutic uses due to their competence as antimicrobial agents. The antimicrobial activity of these bioactive compounds manifests their ability as an antibiofilm agent and is thereby proved to be competent to treat the wide spread of biofilm-associated chronic infections. Rapid development of antibiotic resistance in bacteria has made the treatment of these infections almost impossible by conventional antibiotic therapy, which forced in the switch over to the use of phytocompounds. The present overview deals with the classification of the huge array of phytocompounds according to their chemical nature, detection of their target pathogen, and elucidation of their mode of action.

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Antibiotic survey ofLactococcus lactisstrains to six antibiotics by Etest, and establishment of new susceptibility-resistance cut-off values

Journal of Dairy Research ◽

10.1017/s0022029907002543 ◽

2007 ◽

Vol 74 (3) ◽

pp. 262-268 ◽

Cited By ~ 21

Author(s):

Ana Belén Flórez ◽

Morten Danielsen ◽

Jenni Korhonen ◽

Joanna Zycka ◽

Atte von Wright ◽

...

Keyword(s):

Antibiotic Resistance ◽

Inhibitory Concentration ◽

Tetracycline Resistance ◽

Large Collection ◽

Bacterial Strains ◽

Resistance Determinants ◽

Resistant Strains ◽

Geographical Locations ◽

S Genes ◽

Acquired Antibiotic Resistance

In order to establish cut-off values forLactococcus lactisto six antibiotics to distinguish susceptible and intrinsically resistant strains from those having acquired resistances, the minimum inhibitory concentration (MIC) of tetracycline, erythromycin, clindamycin, streptomycin, chloramphenicol and vancomycin was determined in 93 differentLc. lactisstrains using the Etest. These bacterial strains were originally isolated from dairy and animal sources in widely separated geographical locations. Cut-offs were defined on the basis of the distribution of the MICs frequency of the studied antibiotics, which in the absence of acquired determinants should approach to a normal statistical distribution. In general, the new cut-off values proposed in this study are higher than previously defined (European Commission, 2005. The EFSA Journal 223, 1–12). Based on these new values, all the strains tested were susceptible to erythromycin, chloramphenicol and vancomycin, and 79 susceptible to all six antibiotics. However, 11 strains (around 12%) were considered resistant to tetracycline (six of which had been identified after screening of a large collection of lactococci strains for tetracycline resistance) and five (5·4%) resistant to streptomycin. Of these, two fish isolates proved to be resistance to both tetracycline and streptomycin. From the tetracycline resistant strains,tet(M) and mosaictet(L/S) genes were amplified by PCR, demonstrating they harboured acquired antibiotic resistance determinants.

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Thymol and its Derivatives as Antimicrobial Agents

Natural Product Communications ◽

10.1177/1934578x0800300528 ◽

2008 ◽

Vol 3 (5) ◽

pp. 1934578X0800300 ◽

Cited By ~ 3

Author(s):

Ajai Kumar ◽

Suriya P. Singh ◽

Sudarshan S. Chhokar

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Agents ◽

Single Step ◽

Acid Chlorides ◽

Disc Diffusion ◽

Bacterial Strains ◽

Fungal Strains ◽

Broth Dilution

From the seeds of C arum copticum thymol (1) was isolated as the major component and ten derivatives (2–11) were prepared by reacting it with different acid chlorides in a single step. They were evaluated for antimicrobial activity against twelve bacterial strains and nine fungal strains using disc diffusion and broth dilution assays. Derivative 9 was found to be most active against both bacterial and fungal strains.

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Chemical Compositions and Antimicrobial Activity of the Essential Oils of Piper abbreviatum, P. erecticaule and P. lanatum (Piperaceae)

Natural Product Communications ◽

10.1177/1934578x1400901235 ◽

2014 ◽

Vol 9 (12) ◽

pp. 1934578X1400901 ◽

Cited By ~ 1

Author(s):

Wan Mohd Nuzul Hakimi Wan Salleh ◽

Farediah Ahmad ◽

Khong Heng Yen

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Antimicrobial Agents ◽

Antimicrobial Activities ◽

Dilution Method ◽

Chemical Compositions ◽

Gram Positive Bacteria ◽

Aerial Parts ◽

Ms Analysis ◽

Weak Activity

The study was designed to examine the chemical composition and antimicrobial activities of essential oils extracted from the aerial parts of three Piper species: Piper abbreviatum, P. erecticaule and P. lanatum, all from Malaysia. GC and GC/MS analysis showed qualitative and quantitative differences between these oils. GC and GC-MS analysis of P. abbreviatum, P. erecticaule and P. lanatum oils resulted in the identification of 33, 35 and 39 components, representing 70.5%, 63.4% and 78.2% of the components, respectively. The major components of P. abbreviatum oil were spathulenol (11.2%), ( E)-nerolidol (8.5%) and β-caryophyllene (7.8%), whereas P. erecticaule oil mainly contained β-caryophyllene (5.7%) and spathulenol (5.1%). Borneol (7.5%), β-caryophyllene (6.6%) and α-amorphene (5.6%) were the most abundant components in P. lanatum oil. Antimicrobial activity was carried out using disc diffusion and broth micro-dilution method against nine microorganisms. All of the essential oils displayed weak activity towards Gram-positive bacteria with MIC values in the range 250–500 μg/mL. P. erecticaule oil showed the best activity on Aspergillus niger (MIC 31.3 μg/mL), followed by P. lanatum oil (MIC 62.5 μg/mL). This study demonstrated that the essential oils have potential as antimicrobial agents and may be useful in the pharmaceutical and cosmetics industries.

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