scholarly journals Bistable Bacterial Growth Dynamics in the Presence of Antimicrobial Agents

Antibiotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 87
Author(s):  
Nelly Frenkel ◽  
Ron Saar Dover ◽  
Eve Titon ◽  
Yechiel Shai ◽  
Vered Rom-Kedar
Keyword(s):  
Antimicrobial Agents ◽  
Growth Dynamics ◽  
Initial Population ◽  
Drug Induced ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
Initial Population Size ◽  
Inoculum Effect ◽  
Conventional Antibiotics ◽  
First Time

The outcome of an antibiotic treatment on the growth capacity of bacteria is largely dependent on the initial population size (Inoculum Effect). We characterized and built a model of this effect in E. coli cultures using a large variety of antimicrobials, including conventional antibiotics, and for the first time, cationic antimicrobial peptides (CAMPs). Our results show that all classes of antimicrobial drugs induce an inoculum effect, which, as we explain, implies that the dynamic is bistable: For a range of anti-microbial densities, a very small inoculum decays whereas a larger inoculum grows, and the threshold inoculum depends on the drug concentration. We characterized three distinct classes of drug-induced bistable growth dynamics and demonstrate that in rich medium, CAMPs correspond to the simplest class, bacteriostatic antibiotics to the second class, and all other traditional antibiotics to the third, more complex class. These findings provide a unifying universal framework for describing the dynamics of the inoculum effect induced by antimicrobials with inherently different killing mechanisms.

scholarly journals Efficacy of potassium permanganate and turmeric as antimicrobial agents on the bacterial load and quality of boar semen during preservation at 15 °C

2020 ◽  
Vol 90 (5) ◽  
pp. 443-451
Author(s):  
Nang Kanna Manpoong ◽  
Kutubuddin Ahmed ◽  
Dilip Kumar Bhattacharya ◽  
Dipak Kumar Sarma ◽  
Nekibuddin Ahmed ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Semen Quality ◽  
Sperm Quality ◽  
Bacterial Load ◽  
Conception Rate ◽  
E Coli ◽  
Bacillus Spp ◽  
Boar Semen ◽  
Conventional Antibiotics

The present study was conducted to evaluate the efficacy of different natural antimicrobials agents (KMnO4 and Turmeric) in comparison with conventional antibiotics against the bacterial load and in relation to the quality of boar semen in Modena extender for up to 120 hours of preservation at 15 °C. A total of 56 ejaculates, 14 from each of four Hampshire crossbred boars maintained within the ICAR-AICRP on Pigs, in Guwahati, Assam, India, were utilized in the study. Thirty-two ejaculates, 8 from each of four boars were used to study the effect of antimicrobial agents on semen quality during preservation at 15 °C in Modena extender. A total of 9 different bacterial types were identified from 46 bacterial isolates, obtained from 24 fresh semen samples viz. Staphylococcus aureus (24%), E. coli (22%), Bacillus spp. (13%), Citrobacter spp. (9%), Pseudomonas spp. (9%), Staphylococcus epidermidis (9%), Klebsiella spp. (6%), Streptococcus spp. (6%) and Proteus spp. (2%). The overall sensitivity of the recovered isolates to Gentamicin, Ampicillin, Enrofloxacin, Cloxacillin, Streptomycin, Penicillin, Amoxycilln, Ofloxacin and Tetracyclin were 89, 39, 37, 48, 74, 52, 56, 76 and 63% respectively. The mean sperm motility, intact acrosome, HOST-reacted spermatozoa and bacterial load differed significantly (P˂0.01) between antimicrobial agents (Gentamicin, KMnO4 and Turmeric) and preservation periods (0, 48, 72, 96 and 120 hours). Sperm quality based on Gentamicin was found to be best, followed by Turmeric and KMnO4 during preservation at 15 °C. The conception rate for the semen preserved for 0, 24, 48, 72, 96 and 120 hours of preservation was 83.33, 80.00, 75.00, 66.66, 66.66 and 50.00% respectively. In the present study, the preserved semen with ascending bacterial load containing Gentamicin did not affect the conception rate.

scholarly journals Design, Overproduction and Purification of the Chimeric Phage Lysin MLTphg Fighting against Staphylococcus aureus

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1587
Author(s):  
Feng Wang ◽  
Xiaohang Liu ◽  
Zhengyu Deng ◽  
Yao Zhang ◽  
Xinyu Ji ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Conventional Antibiotics ◽  
Phage Lysin ◽  
Shed Light

With the increasing spread of multidrug-resistant bacterial pathogens, it is of great importance to develop alternatives to conventional antibiotics. Here, we report the generation of a chimeric phage lysin, MLTphg, which was assembled by joining the lysins derived from Meiothermus bacteriophage MMP7 and Thermus bacteriophage TSP4 with a flexible linker via chimeolysin engineering. As a potential antimicrobial agent, MLTphg can be obtained by overproduction in Escherichia coli BL21(DE3) cells and the following Ni-affinity chromatography. Finally, we recovered about 40 ± 1.9 mg of MLTphg from 1 L of the host E. coli BL21(DE3) culture. The purified MLTphg showed peak activity against Staphylococcus aureus ATCC6538 between 35 and 40 °C, and maintained approximately 44.5 ± 2.1% activity at room temperature (25 °C). Moreover, as a produced chimera, it exhibited considerably improved bactericidal activity against Staphylococcus aureus (2.9 ± 0.1 log10 reduction was observed upon 40 nM MLTphg treatment at 37 °C for 30 min) and also a group of antibiotic-resistant bacteria compared to its parental lysins, TSPphg and MMPphg. In the current age of growing antibiotic resistance, our results provide an engineering basis for developing phage lysins as novel antimicrobial agents and shed light on bacteriophage-based strategies to tackle bacterial infections.

scholarly journals Genotypes of Esbl Producing Escherichia Coli and Klebsiella Pneumoniae in Relation to Resistance to Antimicrobial Drugs

PRILOZI ◽  
2014 ◽  
Vol 35 (2) ◽  
pp. 31-38
Author(s):  
Ana Kaftandzieva ◽  
Elena Trajkovska-Dokic ◽  
Vesna Kotevska ◽  
Zaklina Cekovska ◽  
Gordana Jankoska
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Agents ◽  
Single Gene ◽  
Tracheal Aspirate ◽  
Beta Lactams ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
Resistance Patterns ◽  
Antibiotic Resistance Patterns

Abstract The aim of the study was to evaluate the association of drug resistance with β-lactamase gene types in ESBL positive E. coli and Klebsiella pneumoniae-Kp. Material and methods: A total of 251 ESBL-positive E. coli and Kp isolates obtained from urine, tracheal aspirate, wound swab and blood from patients hospitalised at the University Clinics in Skopje were detected using the ESBL set and automated Vitek 2 system. Vitek was also used for susceptibility testing (determination of MIC of 17 antimicrobial agents). Multiplex PCR was used to identify genes for different types of ESBLs in a 100 randomly selected, ESBL positive strains. Results: More of the 87 ESBL typeable isolates (61%) harbour two or more bla genes and the frequency of antibiotic resistance was high in these isolates, compared to those with a single gene. Isolates with ≥ 3 genes were highly resistant to beta-lactams and non-beta lactams used. The degree of resistance to 3rd generation cephalosporins was also high in these isolates (MIC ≥ 64). More of the ESBL-positive isolates showed higher resistance to cefotaxime than to ceftazidime. Conclusion: Identification of the genes is necessary for the surveillance of their transmission in hospitals. Surveillance of antibiotic resistance patterns are crucial to overcome the problems associated with ESBLs.

scholarly journals Molecular Detection of Antibiotic Resistance Genes in Shiga toxin-producing E. coli Isolated from Different Sources

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 344
Author(s):  
Momna Rubab ◽  
Deog-Hwan Oh
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Shiga Toxin ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Foodborne Illnesses ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
Conventional Antibiotics

Shiga toxin-producing Escherichia coli (STEC) is an enteric pathogen associated with human gastroenteritis outbreaks. Extensive use of antibiotics in agriculture selects resistant bacteria that may enter the food chain and potentially causes foodborne illnesses in humans that are less likely to respond to treatment with conventional antibiotics. Due to the importance of antibiotic resistance, this study aimed to investigate the combination of phenotypic and genotypic antibiotic resistance in STEC isolates belonging to serogroups O26, O45, O103, O104, O111, O121, O145, and O157 using disc diffusion and polymerase chain reaction (PCR), respectively. All strains were phenotypically resistant to at least one antibiotic, with 100% resistance to erythromycin, followed by gentamicin (98%), streptomycin (82%), kanamycin (76%), and ampicillin (72%). The distribution of antibiotic resistance genes (ARGs) in the STEC strains was ampC (47%), aadA1 (70%), ere(A) (88%), blaSHV (19%), blaCMY (27%), aac(3)-I (90%), and tet(A) (35%), respectively. The results suggest that most of the strains were multidrug-resistant (MDR) and the most often observed resistant pattern was of aadA1, ere(A), and aac(3)-I genes. These findings indicate the significance of monitoring the prevalence of MDR in both animals and humans around the globe. Hence, with a better understanding of antibiotic genotypes and phenotypes among the diverse STEC strains obtained, this study could guide the administration of antimicrobial drugs in STEC infections when necessary.

scholarly journals Antimicrobial activity of natural compounds from sponge – derived fungus Aspergillus flocculosus 01NT.1.1.5

2020 ◽  
Vol 16 (4) ◽  
pp. 729-735
Author(s):  
Phan Thi Hoai Trinh ◽  
Tran Thi Thanh Van ◽  
Bui Minh Ly ◽  
Byeoung Kyu Choi ◽  
Hee Jae Shin ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Culture Medium ◽  
Antimicrobial Agents ◽  
2D Nmr ◽  
Marine Fungus ◽  
Antimicrobial Drugs ◽  
Etoac Extract ◽  
E Coli ◽  
Chemical Structures ◽  
Pathogenic Microbes

The Aspergillus fungi have been an important source of natural products that are useful for exploration in medicine, agriculture and industry. In our continuous investigation to search for new antimicrobial agents from marine-derived fungi, one new phomaligol A2 (1), together with three known compounds, wasabidienone E (2), aspertetranone D (3) and mactanamide (4), were obtained from the EtOAc extract of the culture medium of the marine-derived fungus Aspergillus flocculosus (A. flocculosus) 01NT.1.1.5 isolated from the sponge Stylissa sp. at Nhatrang Bay, Vietnam. Their chemical structures were elucidated by analysis of 1D and 2D NMR and mass spectroscopic data, as well as by comparison of the corresponding data to those previously reported in the literature. Furthermore, the aim of this study was also to evaluate the antimicrobial activity of these compounds against pathogenic microbes including Escherichia coli (E. coli) ATCC 25922, Pseudomonas aeruginosa (P. aeruginosa) ATCC 27853, Staphylococcus aureus (S. aureus) ATCC 25923, Bacillus cereus (B. cereus) ATCC 11778, Streptococcus faecalis (S. faecalis) ATCC 19433, Listeria monocytogenes (L. monocytogenes) ATCC 19111, and Candida albicans (C. albicans) ATCC 10231. Among the compounds, 1-3 were inhibitory on the growth of the yeast C. albicans with minimum inhibitory concentration (MIC) value of 16 μg/mL, which was more potent than amoxicillin and cefotaxime (MIC > 256 μg/mL), antimicrobial drugs as positive references. Moreover, compounds 1-4 were also found to be active against other pathogens including P. aeruginosa and S. faecalis with MIC values of 16 μg/mL and 32 μg/mL, respectively. Compound 4 had no inhibitory activity against L. monocytogenes, whereas compounds 1-3 had ability to against this strain with MICs of 32 to 64 μg/mL. Four of tested compounds exhibited antibacterial activity against B. cereus and E. coli with MIC values of 64-128 μg/mL. This is the first report about these compounds with antimicrobial activity obtained from marine fungus A. flocculosus isolated in Vietnam.

scholarly journals Antimicrobial Resistance and Virulence Genes of Escherichia coli Isolates from Swine in Ontario

2005 ◽  
Vol 71 (11) ◽  
pp. 6753-6761 ◽  
Author(s):  
Patrick Boerlin ◽  
Rebeccah Travis ◽  
Carlton L. Gyles ◽  
Richard Reid-Smith ◽  
Nicol Janecko Heather Lim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Negative Association ◽  
Bacterial Populations ◽  
E Coli ◽  
Strong Negative Association ◽  
First Time

ABSTRACT A total of 318 Escherichia coli isolates obtained from diarrheic and healthy pigs in Ontario from 2001 to 2003 were examined for their susceptibility to 19 antimicrobial agents. They were tested by PCR for the presence of resistance genes for tetracycline, streptomycin, sulfonamides, and apramycin and of 12 common virulence genes of porcine E. coli. Antimicrobial resistance frequency among E. coli isolates from swine in Ontario was moderate in comparison with other countries and was higher in isolates from pigs with diarrhea than in isolates from healthy finisher pigs. Resistance profiles suggest that cephamycinases may be produced by ≥8% of enterotoxigenic E. coli (ETEC). Resistance to quinolones was detected only in enterotoxigenic E. coli (≤3%). The presence of sul3 was demonstrated for the first time in Canada in porcine E. coli isolates. Associations were observed among tetA, sul1, aadA, and aac(3)IV and among tetB, sul2, and strA/strB, with a strong negative association between tetA and tetB. The paa and sepA genes were detected in 92% of porcine ETEC, and strong statistical associations due to colocation on a large plasmid were observed between tetA, estA, paa, and sepA. Due at least in part to gene linkages, the distribution of resistance genes was very different between ETEC isolates and other porcine E. coli isolates. This demonstrates that antimicrobial resistance epidemiology differs significantly between pathogenic and commensal E. coli isolates. These results may have important implications with regards to the spread and persistence of resistance and virulence genes in bacterial populations and to the prudent use of antimicrobial agents.

scholarly journals Susceptibility of Urinary Tract Bacteria to Newer Antimicrobial Drugs

2016 ◽  
Vol 4 (1) ◽  
pp. 22-24
Author(s):  
Manjula Mehta ◽  
Jyoti Sharma ◽  
Sonia Bhardwaj
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Specific Treatment ◽  
Resistance Pattern ◽  
Antimicrobial Drugs ◽  
Economic Implications ◽  
E Coli ◽  
Tract Infections

Urinary tract infections (UTIs) are among the commonest types of bacterial infections. The antibiotic treatment for UTIs is associated with important medical and economic implications. Many different microorganisms can cause UTIs though the most common pathogens are E. coli and members of family Enterobacteriaceae. The knowledge of etiology and antibiotic resistance pattern of the organisms causing urinary tract infection is essential. The present study was undertaken to evaluate trends of antibiotic susceptibility of commonly isolated uropathogens using newer antimicrobial agents, prulifloxacin, fosfomycin (FOM) and doripenem. We conclude that maintaining a record of culture results and the antibiogram may help clinicians to determine the empirical and/or specific treatment based on the antibiogram of the isolate for better therapeutic outcome.

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

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.

Analysis of the monitoring study of the antibiotic-resistance of the agents of purulent-inflammatory processes of soft tissue

2018 ◽  
Vol 22 (2) ◽  
pp. 285-288
Author(s):  
A.P. Prevar ◽  
A.V. Kryzshanovskaya ◽  
V.A. Radionov ◽  
V.M. Mrug
Keyword(s):  
Soft Tissues ◽  
High Sensitivity ◽  
Biochemical Properties ◽  
Antimicrobial Drugs ◽  
Strict Adherence ◽  
E Coli ◽  
Monitoring Study ◽  
Treatment Measures ◽  
Inflammatory Processes ◽  
Main Factor

The main factor in the treatment of suppurative and inflammatory processes is the timely optimization of treatment measures taking into account the nature of the microflora and its susceptibility to antimicrobial drugs. The purpose of the study is to monitor the spectrum of microorganisms – pathogens of purulent-inflammatory processes of soft tissues in surgical patients; study of the sensitivity of isolated strains to antibiotics. The material was collected in accordance with aseptic rules. The identification of a pure culture of bacteria was carried out according to morphological, culture, biochemical properties, and the presence of virulence enzymes. Sensitivity of bacteria to antibiotics was determined by the standard disks method (by Kirby-Bauer’s). 255 patients with purulent-inflammatory processes of soft tissues were examined for the period from 2014 to 2017. 229 strains of isolated bacteria were included to Escherichia coli, Citrobacer freundii, Enterobacter cloacae, E.aerogenes, Proteus vulgaris, Staphylococcus aureus, S.epidermidis, Streptococcus pyogenes, S.viridians, S.agalactiae, Pseudomonas aeruginosa. The main cause of purulent-inflammatory processes of soft tissues is Staphylococci (67,2%). Compared to previous studies, the number of P.aeruginosa isolated cultures increased (7.9%). In monoculture and in association with other microorganisms, E. coli (9.6% of cases), E.cloacae et aerogenes (3.9% of cases), P.vulgaris (3.9% of cases), C.freundi (2.5% of cases), S.agalactiae, S.pyogenes, S.viridans (3.5%). The number of associated sows reaches 12%. Clinical strains of microorganisms remain most sensitive to fluoroquinolones, cephalosporins, and also retains high sensitivity to gentamicin, lincomycin, rifampicin, which is important for empirical antibiotic therapy. To increase the effectiveness of antibacterial therapy, strict adherence to the mode of appointment of antibiotics, justification of indications, a combination of antibiotics of different spectrum of action, mandatory correction after determining the sensitivity of the pathogen.

Efficacy of Silver Nanoparticles Synthesized from Hymenocallis species (Spider Lilly) Leaf Extract as Antimicrobial Agents

2019 ◽  
Vol 12 (5) ◽  
pp. 4644-4647
Author(s):  
K.K. Gupta ◽  
Neha Kumari ◽  
Neha Sinha ◽  
Akruti Gupta
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Antimicrobial Agents ◽  
Color Change ◽  
Bacterial Species ◽  
Antimicrobial Property ◽  
Biogenic Synthesis ◽  
E Coli ◽  
Light Yellow ◽  
Antibiotic Property

Biogenic synthesis of silver nanoparticles synthesized from Hymenocallis species (Spider Lilly) leaf extract was subjected for investigation of its antimicrobial property against four bacterial species (E. coli, Salmonella sp., Streptococcus sp. & Staphylococcus sp.). The results revealed that synthesized nanoparticles solution very much justify the color change property from initial light yellow to final reddish brown during the synthesis producing a characteristics absorption peak in the range of 434-466 nm. As antimicrobial agents, their efficacy was evaluated by analysis of variance in between the species and among the different concentration of AgNPs solution, which clearly showed that there was significant variation in the antibiotic property between the four different concentrations of AgNPs solution and also among four different species of bacteria taken under studies. However, silver nanoparticles solution of 1: 9 and 1:4 were proved comparatively more efficient as antimicrobial agents against four species of bacteria.

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