scholarly journals Phylogenetic diversity and activity screening of cultivable Actinobacteria isolated from marine sponges and associated environments from the western coast of India

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Ulfat Baig ◽  
Neelesh Dahanukar ◽  
Neha Shintre ◽  
Ketki Holkar ◽  
Anagha Pund ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Phylogenetic Diversity ◽  
Western Coast ◽  
Predatory Behaviour ◽  
Gram Negative ◽  
Content Type ◽  
First Report ◽  
Predatory Activity ◽  
Link Type ◽  
Putative Species

The phylogenetic diversity of cultivable actinobacteria isolated from sponges (Haliclona spp.) and associated intertidal zone environments along the northern parts of the western coast of India were studied using 16S rRNA gene sequences. A subset of randomly selected actinobacterial cultures were screened for three activities, namely predatory behaviour, antibacterial activity and enzyme inhibition. We recovered 237 isolates from the phylum Actinobacteria belonging to 19 families and 28 genera, which could be attributed to 95 putative species using maximum-likelihood partition and 100 putative species using Bayesian partition in Poisson tree processes. Although the trends in the discovery of actinobacterial genera isolated from sponges were consistent with previous studies from different study areas, we provide the first report of nine actinobacterial species from sponges. We observed widespread non-obligate epibiotic predatory behaviour in eight actinobacterial genera and we provide the first report of predatory activity in Brevibacterium , Glutamicibacter , Micromonospora , Nocardiopsis , Rhodococcus and Rothia . Sponge-associated actinobacteria showed significantly more predatory behaviour than environmental isolates. While antibacterial activity by actinobacterial isolates mainly affected Gram-positive target bacteria with little or no effect on Gram-negative bacteria, predation targeted both Gram-positive and Gram-negative prey with equal propensity. Actinobacterial isolates from both sponges and associated environments produced inhibitors of serine proteases and angiotensin-converting enzyme. Predatory behaviour was strongly associated with inhibition of trypsin and chymotrypsin. Our study suggests that the sponges and associated environments of the western coast of India are rich in actinobacterial diversity, with widespread predatory activity, antibacterial activity and production of enzyme inhibitors. Understanding the diversity and associations among various actinobacterial activities – with each other and the source of isolation – can provide new insights into marine microbial ecology and provide opportunities to isolate novel therapeutic agents.

scholarly journals Phylogenetic diversity and activity screening of cultivable actinobacteria isolated from marine sponges and associated environments from the western coast of India

2020 ◽  
Author(s):  
Ulfat Baig ◽  
Neelesh Dahanukar ◽  
Neha Shintre ◽  
Ketki Holkar ◽  
Anagha Pund ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Phylogenetic Diversity ◽  
Predatory Behavior ◽  
Rrna Gene ◽  
Western Coast ◽  
Gram Positive ◽  
Gram Negative ◽  
First Report ◽  
Predatory Activity ◽  
Putative Species

AbstractPhylogenetic diversity of cultivable actinobacteria isolated from sponges (Haliclona spp.) and associated environments of intertidal zones, along the northern parts of west coast of India, were studied using 16S rRNA gene sequences. A subset of actinobacteria were screened for three activities, namely predatory behavior, antibacterial activity and enzyme inhibition. We recovered 237 isolates of actinobacteria belonging to 19 families and 28 genera, which could be attributed to 95 putative species using maximum likelihood partition and 100 putative species using Bayesian partition in Poisson Tree Processes. Although the trends in the discovery of actinobacterial genera isolated from sponges was consistent with previous studies from different study areas, we provide first report of nine actinobacterial species from sponges. We observed widespread non-obligate epibiotic predatory behavior in eight actinobacterial genera and we provide first report of predatory activity in Brevibacterium, Glutamicibacter, Micromonospora, Nocardiopsis, Rhodococcus and Rothia. Sponge associated actinobacteria showed significantly more predatory behavior than environmental isolates. While antibacterial activity by actinobacterial isolates mainly affected Gram-positive target bacteria with little to no effect on Gram-negative bacteria, predation targeted both Gram-positive and Gram-negative prey with equal propensity. Actinobacterial isolates from both sponge and associated environment produced inhibitors of serine proteases and angiotensin converting enzyme. Predatory behavior was strongly associated with inhibition of trypsin and chymotrypsin. Our study suggests that sponge and associated environment of western coast of India are rich in actinobacterial diversity with widespread predatory activity, antibacterial activity and production of enzyme inhibitors. Understanding diversity and associations among various actinobacterial activities, with each other and the source of isolation, can provide new insights in marine microbial ecology and provide opportunities to isolate novel therapeutic agents.

scholarly journals In vitro synergy of 5-nitrofurans, vancomycin and sodium deoxycholate against Gram-negative pathogens

2021 ◽  
Author(s):  
Catrina Olivera ◽  
Vuong Van Hung Le ◽  
Catherine Davenport ◽  
Jasna Rakonjac
Keyword(s):  
Growth Inhibition ◽  
Type Species ◽  
Sodium Deoxycholate ◽  
Gram Positive ◽  
Bacterial Killing ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Time Kill

Introduction. There is an urgent need for effective therapies against bacterial infections, especially those caused by antibiotic-resistant Gram-negative pathogens. Hypothesis. Synergistic combinations of existing antimicrobials show promise due to their enhanced efficacies and reduced dosages which can mitigate adverse effects, and therefore can be used as potential antibacterial therapy. Aim. In this study, we sought to characterize the in vitro interaction of 5-nitrofurans, vancomycin and sodium deoxycholate (NVD) against pathogenic bacteria. Methodology. The synergy of the NVD combination was investigated in terms of growth inhibition and bacterial killing using checkerboard and time-kill assays, respectively. Results. Using a three-dimensional checkerboard assay, we showed that 5-nitrofurans, sodium deoxycholate and vancomycin interact synergistically in the growth inhibition of 15 out of 20 Gram-negative strains tested, including clinically significant pathogens such as carbapenemase-producing Escherichia coli , Klebsiella pneumoniae and Acinetobacter baumannii , and interact indifferently against the Gram-positive strains tested. The time-kill assay further confirmed that the triple combination was bactericidal in a synergistic manner. Conclusion. This study demonstrates the synergistic effect of 5-nitrofurans, sodium deoxycholate and vancomycin against Gram-negative pathogens and highlights the potential of the combination as a treatment for Gram-negative and Gram-positive infections.

Genomic deletions in Rhodococcus based on transformation of linear heterologous DNA

Microbiology ◽  
2021 ◽  
Author(s):  
Divya Singhi ◽  
Shabnam Parwin ◽  
Preeti Srivastava
Keyword(s):  
Rapid Method ◽  
Genome Engineering ◽  
Cost Effective ◽  
Cell Disruption ◽  
Content Type ◽  
First Report ◽  
Genomic Deletions ◽  
Linear Dna ◽  
Link Type ◽  
Successful Expression

Several genome engineering methods have been developed for Rhodococcus . However, they suffer from limitations such as extensive cloning, multiple steps, successful expression of heterologous genes via plasmid etc. Here, we report a rapid method for performing genomic deletions/disruptions in Rhodococcus spp. using heterologous linear DNA. The method is cost effective and less labour intensive. The applicability of the method was demonstrated by successful disruption of rodA and orphan parA. None of the disrupted genes were found to be essential for the viability of the cell. Disruption of orphan parA and rodA resulted in elongated cells and short rods, respectively. This is the first report demonstrating disruption of rodA and orphan parA genes by electroporation of heterologous linear DNA in Rhodococcus spp.

Microbiological pattern of prosthetic hip and knee infections: a high-volume, single-centre experience in China

2021 ◽  
Author(s):  
Yali Yu ◽  
Yiyi Kong ◽  
Jing Ye ◽  
Aiguo Wang ◽  
Wenteng Si
Keyword(s):  
Antibiotic Treatment ◽  
Prolonged Treatment ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Musculoskeletal Infection ◽  
Gram Negative ◽  
Content Type ◽  
Empirical Antibiotic Treatment ◽  
Link Type

Introduction. Prosthetic joint infection (PJI) is a serious complication after arthroplasty, which results in high morbidity, prolonged treatment and considerable healthcare expenses in the absence of accurate diagnosis. In China, microbiological data on PJIs are still scarce. Hypothesis/Gap Statement. The incidence of PJI is increasing year by year, and the proportion of drug-resistant bacteria infection is nicreasing, which brings severe challenges to the treatment of infection. Aim. This study aimed to identify the pathogens in PJIs, multi-drug resistance, and evaluate the effect of the treatment regimen in patients with PJI. Methodology. A total of 366 consecutive cases of PJI in the hip or knee joint were admitted at the Orthopedic Surgery Center in Zhengzhou, China from January 2012 to December 2018. Infections were confirmed in accordance with the Infectious Diseases Society of America and the Musculoskeletal Infection Society (MSIS) criteria. Concurrently, patient demographic data, incidence and antibiotic resistance were investigated. Statistical differences were analysed using Fisher’s exact test or chi-square test. Results. Altogether, 318 PJI cases satisfying the inclusion criteria were enrolled in this study, including 148 with hip PJIs and 170 with knee PJIs. The average age of patients with hip PJIs was lesser than that of patients with knee PJIs (56.4 vs. 68.6 years). Meanwhile, coagulase-negative staphylococcus (CNS, n=81, 25.5 %) was the predominant causative pathogen, followed by Staphylococcus aureus (n=67, 21.1 %). Methicillin-resistant Staphylococcus (MRS) was identified in 28.9 % of PJI patients. In addition, fungus accounted for 4.8 % (n=15), non-tuberculosis mycobacterium accounted for 1.6 % (n=5), polymicrobial pathogens accounted for 21.7 % (n=69), and Gram-negative bacteria accounted for 7.9 % (n=25) of the total infections. The results of antibiotic susceptibility testing showed that gentamicin and clindamycin β-lactam antibiotics were poorly susceptible to Gram-positive isolates, but they were sensitive to rifampicin, linezolid and vancomycin. While antibiotics such as amikacin and imipenem were effective against Gram-negative bacteria, there was a high resistance rate of other pathogens to gentamicin, clindamycin and some quinolone antibacterial drugs. Empirical antibiotic treatment should combine vancomycin and cephalosporin, levofloxacin or clindamycin. When the pathogen is confirmed, the treatment should be individualized. Conclusions. The prevalence of culture-negative PJIs is still very high. Gram-positive bacteria are still the main type of pathogens that cause PJIs. Attention should be paid to the high incidence of MRS, such as MRSA and MR-CNS, among PJI patients. Empirical antibiotic treatment should cover Gram-positive isolates, especially Staphylococcus .

Synthesis of new azobenzene dyes clubbed with thiazolidinone moiety and their applications

2020 ◽  
Vol 49 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Hatem E. Gaffer ◽  
Ismail I. Althagafi
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Proton Nuclear Magnetic Resonance ◽  
Spectral Studies ◽  
Gram Negative Bacteria ◽  
Anticancer Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Polyester Fabrics ◽  
Content Type

Purpose The purpose of this paper is to synthesize some new azobenzene dyestuffs clubbed with thiazolidinone moiety and their solicitation in dyeing polyester fabrics representing their antibacterial evaluation. Design/methodology/approach Herein, the authors report the synthesis of new thiazolidinone moiety after the coupling of diazotized 4-aminoacetophenone with resorcinol. The newly synthesized dyes were characterized by IR, elemental analysis, mass spectroscopy and proton nuclear magnetic resonance (1H NMR) spectral studies. The characteristics of dyeing of these dyestuffs were evaluated at optimum conditions. Concurrent with dyeing of polyester fabric for synthesized dyes with their antibacterial activity was estimated. Antimicrobial activity of the dyed fabrics at different concentrations was evaluated against gram-positive and gram-negative bacteria. Findings Synthesized azobenzene dyestuffs clubbed with thiazolidinone dyes were applied on polyester fabrics. It was remarked that the modified dyes exhibited better colourfastness properties. Furthermore, the synthesized dyes revealed antimicrobial activity against gram-positive and gram-negative bacteria. Research limitations/implications The synthesized azobenzene dyes for polyester dyeing were not bore earlier. Practical implications The azobenzene dyes were accountable for giving improved colourfastness properties on polyester fabrics. Social implications The synthesized azobenzene derivatives are sensibly expensive and applicable dyes accompanied with good antimicrobial and anticancer activities. Originality/value A common process could be affording textiles of colour and antibacterial assets. The newly synthesized dyes containing thiazolidinone moieties with azobenzene coupler showed interesting disperse colourant for polyester with good antibacterial activity.

scholarly journals Pseudomonas aeruginosa Alginate Benefits Staphylococcus aureus?

2020 ◽  
Vol 202 (8) ◽  
Author(s):  
Michael J. Schurr
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Cell Membrane ◽  
Membrane Integrity ◽  
Partial Explanation ◽  
Content Type ◽  
First Report ◽  
Cell Membrane Integrity ◽  
Link Type

ABSTRACT In this issue of Journal of Bacteriology, Price et al. show that the Pseudomonas aeruginosa-produced exopolysaccharide alginate protects Staphylococcus aureus by dampening the expression of P. aeruginosa virulence products that usually inhibit S. aureus respiration and cell membrane integrity when the two organisms compete in other environments (C. E. Price, D. G. Brown, D. H. Limoli, V. V. Phelan, and G. A. O’Toole, J Bacteriol 202:e00559-19, 2020, https://doi.org/10.1128/jb.00559-19). This is the first report that exogenously added alginate affects P. aeruginosa competition and provides a partial explanation for S. aureus and P. aeruginosa coinfections in cystic fibrosis.

scholarly journals In VitroAntibacterial Activity of AZD0914, a New Spiropyrimidinetrione DNA Gyrase/Topoisomerase Inhibitor with Potent Activity against Gram-Positive, Fastidious Gram-Negative, and Atypical Bacteria

2014 ◽  
Vol 59 (1) ◽  
pp. 467-474 ◽  
Author(s):  
Michael D. Huband ◽  
Patricia A. Bradford ◽  
Linda G. Otterson ◽  
Gregory S. Basarab ◽  
Amy C. Kutschke ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Legionella Pneumophila ◽  
Bacterial Species ◽  
Dna Gyrase ◽  
Cross Resistance ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Topoisomerase Inhibitor

ABSTRACTAZD0914 is a new spiropyrimidinetrione bacterial DNA gyrase/topoisomerase inhibitor with potentin vitroantibacterial activity against key Gram-positive (Staphylococcus aureus,Staphylococcus epidermidis,Streptococcus pneumoniae,Streptococcus pyogenes, andStreptococcus agalactiae), fastidious Gram-negative (Haemophilus influenzaeandNeisseria gonorrhoeae), atypical (Legionella pneumophila), and anaerobic (Clostridium difficile) bacterial species, including isolates with known resistance to fluoroquinolones. AZD0914 works via inhibition of DNA biosynthesis and accumulation of double-strand cleavages; this mechanism of inhibition differs from those of other marketed antibacterial compounds. AZD0914 stabilizes and arrests the cleaved covalent complex of gyrase with double-strand broken DNA under permissive conditions and thus blocks religation of the double-strand cleaved DNA to form fused circular DNA. Whereas this mechanism is similar to that seen with fluoroquinolones, it is mechanistically distinct. AZD0914 exhibited low frequencies of spontaneous resistance inS. aureus, and if mutants were obtained, the mutations mapped togyrB. Additionally, no cross-resistance was observed for AZD0914 against recent bacterial clinical isolates demonstrating resistance to fluoroquinolones or other drug classes, including macrolides, β-lactams, glycopeptides, and oxazolidinones. AZD0914 was bactericidal in both minimum bactericidal concentration andin vitrotime-kill studies. Inin vitrocheckerboard/synergy testing with 17 comparator antibacterials, only additivity/indifference was observed. The potentin vitroantibacterial activity (including activity against fluoroquinolone-resistant isolates), low frequency of resistance, lack of cross-resistance, and bactericidal activity of AZD0914 support its continued development.

scholarly journals Infective endocarditis caused by Cardiobacterium valvarum

2019 ◽  
Vol 1 (8) ◽  
Author(s):  
Yohei Washio ◽  
Shun-ichiro Sakamoto ◽  
Ryoichi Saito ◽  
Takahito Nei ◽  
Masayo Morishima ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Ribosomal Rna ◽  
Transthoracic Echocardiography ◽  
Type Species ◽  
Blood Cultures ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Conventional Methods ◽  
Positive Results

We report a case with infective endocarditis (IE) due to Cardiobacterium valvarum . The patient was a 57-year-old male, who was referred to our hospital based on suspected IE detected by transthoracic echocardiography at a neighbourhood clinic. Three sets of blood cultures obtained on admission yielded positive results, and revealed rather slender and linear Gram-negative bacilli with a rosette formation that dyed minimally, with a pale white appearance. Although no isolates were identified by conventional methods, C. valvarum was ultimately identified by 16 S ribosomal RNA genotyping. HACEK group strains are difficult to identify by conventional methods. Therefore, if Gram-negative bacilli are isolated from IE patients, 16 S ribosomal RNA genotyping will be necessary. Furthermore, IE due to C. valvarum is very rare. We thus discuss our case in comparison with previous reports.

scholarly journals Loss of the virulence plasmid by Shigella sonnei promotes its interactions with CD207 and CD209 receptors

2021 ◽  
Vol 70 (3) ◽  
Author(s):  
Bi-cong Wu ◽  
Njiri A. Olivia ◽  
John Mambwe Tembo ◽  
Ying-xia He ◽  
Ying-miao Zhang ◽  
...  
Keyword(s):  
Type Species ◽  
Shigella Sonnei ◽  
Virulence Plasmid ◽  
Gram Negative Bacteria ◽  
Lectin Receptors ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
O Antigen ◽  
Rough Strain

Introduction. Shigella sonnei, the cause of bacillary dysentery, belongs to Gram-negative enteropathogenic bacteria. S. sonnei contains a 210 kb virulence plasmid that encodes an O-antigen gene cluster of LPSs. However, this virulence plasmid is frequently lost during replication. It is well-documented that after losing the O-antigen and becoming rough strains, the Gram-negative bacteria may express an LPS core on its surface. Previous studies have suggested that by using the LPS core, Gram-negative bacteria can interact with several C-type lectin receptors that are expressed on antigen-presenting cells (APCs). Hypothesis/Gap Statement. S. sonnei by losing the virulence plasmid may hijack APCs via the interactions of LPS-CD209/CD207. Aim. This study aimed to investigate if the S. sonnei rough strain, by losing the virulence plasmid, interacted with APCs that express C-type lectins of human CD207, human CD209a and mouse CD209b. Methodology. SDS-PAGE silver staining was used to examine the O-antigen expression of S. sonnei WT and its rough strain. Invasion assays and inhibition assays were used to examine the ability of S. sonnei WT and its rough strain to invade APCs and investigate whether CD209 and CD207 are receptors for phagocytosis of rough S. sonnei . Animal assays were used to observe the dissemination of S. sonnei . Results. S. sonnei did not express O-antigens after losing the virulence plasmid. The S. sonnei rough strain invades with APCs, including human dendritic cells (DCs) and mouse macrophages. CD209 and CD207 are receptors for phagocytosis of rough S. sonnei . Expression of the O-antigen reduces the ability of the S. sonnei rough strain to be disseminated to mesenteric lymph nodes and spleens. Conclusion. This work demonstrated that S. sonnei rough strains – by losing the virulence plasmid – invaded APCs through interactions with CD209 and CD207 receptors.

scholarly journals Antibacterial activity of high-dose nitric oxide against pulmonary Mycobacterium abscessus disease

2020 ◽  
Vol 2 (9) ◽  
Author(s):  
Kristijan Bogdanovski ◽  
Trisha Chau ◽  
Chevalia J. Robinson ◽  
Sandra D. MacDonald ◽  
Ann M. Peterson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antibacterial Activity ◽  
Type Species ◽  
Mycobacterium Abscessus ◽  
Clinical Isolates ◽  
Content Type ◽  
Link Type ◽  
Susceptibility Tests ◽  
Inhaled No

Introduction. Mycobacterium abscessus is an emerging pulmonary pathogen with limited treatment options. Nitric oxide (NO) demonstrates antibacterial activity against various bacterial species, including mycobacteria. In this study, we evaluated the effect of adjunctive inhaled NO therapy, using a novel NO generator, in a CF patient with pulmonary M. abscessus disease, and examined heterogeneity of response to NO in vitro. Methods. In the compassionate-use treatment, a 24-year-old CF patient with pulmonary M. abscessus was treated with two courses of adjunctive intermittent NO, first at 160 p.p.m. for 21 days and subsequently by escalating the dose up to 240 p.p.m. for 8 days. Methemoglobin, pulmonary function, 6 min walk distance (6MWD), qualify of life and sputum microbiology were assessed. In vitro susceptibility tests were performed against patient’s isolate and comparison clinical isolates and quantified by Hill’s slopes calculated from time–kill curves. Results. M. abscessus lung infection eradication was not achieved, but improvements in selected qualify of life domains, lung function and 6MWD were observed during the study. Inhaled NO was well tolerated at 160 p.p.m. Dosing at 240 p.p.m. was stopped due to adverse symptoms, although methemoglobin levels remained within safety thresholds. In vitro susceptibility tests showed a dose-dependent NO effect on M. abscessus susceptibility and significant heterogeneity in response between M. abscessus clinical isolates. The patient’s isolate was found to be the least susceptible strain in vitro. Conclusion. These results demonstrate heterogeneity in M. abscessus susceptibility to NO and suggest that longer treatment regimens could be required to see the reduction or eradication of more resistant pulmonary strains.

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