scholarly journals A Pilot Study of Bacteriological Population Changes through Potable Water Treatment and Distribution

2000 ◽  
Vol 66 (1) ◽  
pp. 268-276 ◽  
Author(s):  
Cheryl D. Norton ◽  
Mark W. LeChevallier
Keyword(s):  
Pilot Study ◽  
Biologically Active ◽  
Plate Count ◽  
Identification System ◽  
Population Changes ◽  
Gram Positive ◽  
Pipe Surface ◽  
Treated Water ◽  
Gram Positive Bacteria ◽  
Biofilm Development

ABSTRACT This pilot study compares the compositions of bacterial biofilms in pipe networks supplied with water containing either high levels of biodegradable organic matter (BOM) or low levels of BOM (conventionally or biologically treated, respectively). The Microbial Identification System for fatty acid analysis was utilized in this study to identify a large number of organisms (>1,400) to determine population changes in both conventionally and biologically treated water and biofilms. Data generated during this study indicated that suspended bacteria have little impact on biofilms, and despite treatment (conventional or biological), suspended microbial populations were similar following disinfection. Prechlorination with free chlorine resulted not only in reduced plate count values but also in a dramatic shift in the composition of the bacterial population to predominately gram-positive bacteria. Chlorination of biologically treated water produced the same shifts toward gram-positive bacteria. Removal of assimilable organic carbon by the biologically active filters slowed the rate of biofilm accumulation, but biofilm levels were similar to those found in conventionally treated water within several weeks. Iron pipes stimulated the rate of biofilm development, and bacterial levels on disinfected iron pipes exceeded those for chlorinated polyvinyl chloride pipes. The study showed that the iron pipe surface dramatically influenced the composition, activity, and disinfection resistance of biofilm bacteria.

scholarly journals Synthesis and Evaluation of Antimicrobial and Cytotoxic Activity of Oxathiine-Fused Quinone-Thioglucoside Conjugates of Substituted 1,4-Naphthoquinones

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3577
Author(s):  
Yuri E. Sabutski ◽  
Ekaterina S. Menchinskaya ◽  
Ludmila S. Shevchenko ◽  
Ekaterina A. Chingizova ◽  
Artur R. Chingizov ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Cytotoxic Activity ◽  
Antimicrobial Activities ◽  
Biologically Active ◽  
Hydroxyl Group ◽  
Diffusion Method ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
High Cytotoxic Activity ◽  
Derivatives Of

A series of new tetracyclic oxathiine-fused quinone-thioglycoside conjugates based on biologically active 1,4-naphthoquinones and 1-mercapto derivatives of per-O-acetyl d-glucose, d-galactose, d-xylose, and l-arabinose have been synthesized, characterized, and evaluated for their cytotoxic and antimicrobial activities. Six tetracyclic conjugates bearing a hydroxyl group in naphthoquinone core showed high cytotoxic activity with EC50 values in the range of 0.3 to 0.9 μM for various types of cancer and normal cells and no hemolytic activity up to 25 μM. The antimicrobial activity of conjugates was screened against Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), and fungus Candida albicans by the agar diffusion method. The most effective juglone conjugates with d-xylose or l-arabinose moiety and hydroxyl group at C-7 position of naphthoquinone core at concentration 10 µg/well showed antimicrobial activity comparable with antibiotics vancomicin and gentamicin against Gram-positive bacteria strains. In liquid media, juglone-arabinosidic tetracycles showed highest activity with MIC 6.25 µM. Thus, a positive effect of heterocyclization with mercaptosugars on cytotoxic and antimicrobial activity for group of 1,4-naphthoquinones was shown.

scholarly journals Study of Microbiological Quality of Biscuits from Street Side Bakery Shops at Dehradun City, India

2020 ◽  
pp. 319-326
Author(s):  
Irtiqa Syed ◽  
Rajendra Prasad ◽  
Adeeba Naaz
Keyword(s):  
Agar Medium ◽  
Microbiological Quality ◽  
Nutrient Agar ◽  
Morphological Observation ◽  
Plate Count ◽  
Bacterial Isolates ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Nutrient Agar Medium

<p>In the present study, microbiological quality of biscuits from street side bakery shops at Dehardun city, India was conducted. A total 11 samples of bakery biscuits were collected randomly and analysed for their microbiologically quality by standard plate count method. Pure cultures of bacterial isolates were prepared by streaking on nutrient agar medium. Bacterial isolates were further studied for morphological characters, culture characters on nutrient agar medium and biochemical testes in laboratory. All samples studies were found contaminated by a variety of bacteria. The highest bacterial load was 2.2 ×105 cfu/g and lowest was 0.1×103 cfu/g, respectively. Morphological observation, culture characters and results of biochemical tests of bacterial isolates were compared with standard results of known bacteria. The bacterial isolated were identified as Alcaligenes faecalis, Bacillus cereus, Micrococcus luteus, Pseudomonas aeruginosa, Streptococcus lactis and Staphylococcus aureus, respectively. Among these, two isolates i.e., A. faecalis and P. aeruginosa were gram negative and other isolates were gram positive bacteria which suggested the poor hygienic conditions inside the bakery during preparation and storage of biscuits. Gram positive bacteria might be contaminated during storage and by bad handling. These food spoiling bacteria might be responsible for food-borne infection and diseases. Therefore, care should be taken while purchasing such products and should be purchased from certified bakery shop.</p>

scholarly journals Synthesis and Antimicrobial Activity of Burkholderia-Related 4-Hydroxy-3-Methyl-2-Alkenylquinolones (HMAQs) and Their N-Oxide Counterparts

2020 ◽  
Author(s):  
Marianne Piochon ◽  
Pauline M. L. Coulon ◽  
Armand Caulet ◽  
Marie-Christine Groleau ◽  
Eric Déziel ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biologically Active ◽  
Specific Class ◽  
Gram Positive ◽  
Carbonate Group ◽  
Gram Positive Bacteria ◽  
Alkenyl Chain ◽  
Optimized Conditions ◽  
Burkholderia Ambifaria

ABSTRACT: The Burkholderia genus offers a promising potential in medicine because of the diversity of biologically active natural products encoded in its genome. Some pathogenic Burkholderia spp. biosynthesize a specific class of antimicrobial 2-alkyl-4(1H)-quinolones, i.e., 4-hydroxy-3-methyl-2-alkenylquinolones (HMAQs) and their N-oxide derivatives (HMAQNOs). Herein, we report the synthesis of a series of six HMAQs and HMAQNOs featuring a trans-∆<sup>2</sup> double bond at the C2-alkyl chain. The quinolone scaffold was obtained via the Conrad-Limpach approach while the (E)-2-alkenyl chain was inserted through Suzuki-Miyaura cross-coupling under microwave radiation without noticeable isomerization according to the optimized conditions. Subsequent oxidation of enolate-protected HMAQs cleanly led to the formation of HMAQNOs following cleavage of the ethyl carbonate group. Synthetic HMAQs and HMAQNOs were in vitro evaluated for their antimicrobial activity against different Gram-negative and Gram-positive bacteria as well as against fungi and yeasts. The biological results support and extend the potential of HMAQs and HMAQNOs as antimicrobials, especially against Gram-positive bacteria. We also confirm the involvement of HMAQs in the autoregulation of the Hmq system in Burkholderia ambifaria.

scholarly journals Pili in Gram-positive bacteria: assembly, involvement in colonization and biofilm development

2008 ◽  
Vol 16 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Anjali Mandlik ◽  
Arlene Swierczynski ◽  
Asis Das ◽  
Hung Ton-That
Keyword(s):  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Biofilm Development

Biologically active binaphthol-scaffolded imidazolium salts

MedChemComm ◽  
2014 ◽  
Vol 5 (4) ◽  
pp. 436-440 ◽  
Author(s):  
Marc Vidal ◽  
Claude-Rosny Elie ◽  
Shirley Campbell ◽  
Audrey Claing ◽  
Andreea R. Schmitzer
Keyword(s):  
Antimicrobial Activity ◽  
Lipid Membrane ◽  
Biologically Active ◽  
Imidazolium Salts ◽  
Gram Positive ◽  
Gram Positive Bacteria

This work describes the antimicrobial activity and selectivity for Gram-positive bacteria of imidazolium-functionalized binols, as a result of their insertion into the lipid membrane and alteration of its permeability.

scholarly journals The First Structure of a Lantibiotic Immunity Protein, SpaI from Bacillus subtilis, Reveals a Novel Fold

2012 ◽  
Vol 287 (42) ◽  
pp. 35286-35298 ◽  
Author(s):  
Nina A. Christ ◽  
Sophie Bochmann ◽  
Daniel Gottstein ◽  
Elke Duchardt-Ferner ◽  
Ute A. Hellmich ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Lipid Membranes ◽  
Biologically Active ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Lipid Ii ◽  
Terminal Fragment ◽  
Terminal Amino ◽  
Immunity Mechanism ◽  
Producer Strains

Lantibiotics are peptide-derived antibiotics that inhibit the growth of Gram-positive bacteria via interactions with lipid II and lipid II-dependent pore formation in the bacterial membrane. Due to their general mode of action the Gram-positive producer strains need to express immunity proteins (LanI proteins) for protection against their own lantibiotics. Little is known about the immunity mechanism protecting the producer strain against its own lantibiotic on the molecular level. So far, no structures have been reported for any LanI protein. We solved the structure of SpaI, a LanI protein from the subtilin producing strain Bacillus subtilis ATCC 6633. SpaI is a 16.8-kDa lipoprotein that is attached to the outside of the cytoplasmic membrane via a covalent diacylglycerol anchor. SpaI together with the ABC transporter SpaFEG protects the B. subtilis membrane from subtilin insertion. The solution-NMR structure of a 15-kDa biologically active C-terminal fragment reveals a novel fold. We also demonstrate that the first 20 N-terminal amino acids not present in this C-terminal fragment are unstructured in solution and are required for interactions with lipid membranes. Additionally, growth tests reveal that these 20 N-terminal residues are important for the immunity mediated by SpaI but most likely are not part of a possible subtilin binding site. Our findings are the first step on the way of understanding the immunity mechanism of B. subtilis in particular and of other lantibiotic producing strains in general.

Effects of Diacetyl and Carbon Dioxide on Spoilage Microflora in Ground Beef

2002 ◽  
Vol 65 (3) ◽  
pp. 523-527 ◽  
Author(s):  
ANISHA M. WILLIAMS-CAMPBELL ◽  
JAMES M. JAY
Keyword(s):  
Ground Beef ◽  
Plate Count ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Plate Count Agar ◽  
Plate Counts ◽  
Meat Samples ◽  
Spoilage Microflora

The effect of CO2 and diacetyl, alone or in combination, on spoilage microflora in ground beef was determined. Ground beef was treated with 20, 30, or 40% CO2 for 22 days (study I); 20, 50, or 100 μg/g diacetyl for 26 days (study II); or a combination of 20% CO2 and 100 μg/g diacetyl for 40 days (study III). Antimicrobial effectiveness was determined by aerobic plate counts (log10 CFU/g) using plate count agar (total aerobic bacteria), deMan Rogosa Sharpe (MRS) Lactobacillus agar (gram-positive bacteria), MacConkey agar (gram-negative bacteria), pH, and informal organoleptic assessments (by appearance and by odor). In study I, total bacteria and pH increased by day 4 in control meat samples. For all CO2 levels, gram-negative bacteria decreased and gram-positive bacteria increased compared with untreated controls. The pH remained constant for CO2-treated meat. Control samples had an off-odor and a brown appearance, while CO2-treated samples had no off-odor but did have a brown appearance. For samples treated with diacetyl (study II), spoilage was evident by day 7 for samples treated with 0, 20, and 50 μg/g diacetyl for all parameters examined. Ground beef treated with 100 μg/g diacetyl was spoiled on day 12. Diacetyl was detected (by odor) in samples that were treated with 100 μg/g diacetyl and had a brown appearance. Meat samples treated with the combination of CO2 and diacetyl (study III) showed that the addition of diacetyl did not have an additive effect on microbial growth. Combination-treated meat maintained a red appearance and no off-odor. Diacetyl and CO2 could be used in combination to maintain a red color and inhibit spoilage microorganisms.

scholarly journals Biofilm-Related Infections in Gram-Positive Bacteria and the Potential Role of the Long-Acting Agent Dalbavancin

2021 ◽  
Vol 12 ◽  
Author(s):  
Alessandra Oliva ◽  
Stefania Stefani ◽  
Mario Venditti ◽  
Enea Gino Di Domenico
Keyword(s):  
Public Health Problem ◽  
Major Public Health Problem ◽  
Bacterial Cells ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Long Acting ◽  
Acting Agent ◽  
Biofilm Development

Infections caused by Gram-positive bacteria are a major public health problem due to their increasing resistance to antibiotics. Staphylococcus and Enterococcus species’ resistance and pathogenicity are enhanced by their ability to form biofilm. The biofilm lifestyle represents a significant obstacle to treatment because bacterial cells become highly tolerant to a wide range of antimicrobial compounds normally effective against their planktonic forms. Thus, novel therapeutic strategies targeting biofilms are urgently needed. The lipoglycopeptide dalbavancin is a long-acting agent for treating acute bacterial skin and skin structure infections caused by a broad range of Gram-positive pathogens. Recent studies have shown promising activity of dalbavancin against Gram-positive biofilms, including methicillin-resistant S. aureus (MRSA), methicillin-resistant S. epidermidis (MRSE), and vancomycin-susceptible enterococci. This review outlines the mechanisms regulating biofilm development in Staphylococcus and Enterococcus species and the clinical impact of biofilm-related infections. In addition, it discusses the clinical implications and potential therapeutic perspectives of the long-acting drug dalbavancin against biofilm-forming Gram-positive pathogens.

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