scholarly journals Coatings Based on Two-Dimensionally Ordered Linear Chain Carbon for Protection of Titanium Implants from Microbial Colonization

2019 ◽  
Vol 25 (2) ◽  
pp. 111-120 ◽  
Author(s):  
D. V. Tapalski ◽  
N. S. Nikolaev ◽  
A. V. Ovsyankin ◽  
V. D. Kochakov ◽  
E. A. Golovina ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Linear Chain ◽  
Bactericidal Effect ◽  
Titanium Implants ◽  
Microbial Colonization ◽  
Clinical Isolates ◽  
Mechanical Resistance ◽  
Crystal Violet Solution ◽  
Biological Compatibility ◽  
Taxonomic Groups

Purpose of the study – to evaluate the antibacterial activity and biological compatibility of alloy coatings based on two-dimensionally ordered linear chain carbon (TDOLCC).Materials and Methods. Coatings based on TDOLCC were synthesized using alloying additions like nitrogen (TDOLCC+N) and silver (TDOLCC+Ag) on the surfaces of titanium plates and polystyrene plates by the ion-stimulated carbon condensation in a vacuum. The authors examined the superficial bactericidal activity of the coatings and its resistance to mechanical effects. Coated plates were evaluated in respect of rate of microbial biofilms formation by clinical isolates with multiple and extreme antibiotic resistance. Specimens were colored with crystal violet solution to visualize the biofilms. Cytotoxic effect of coatings was evaluated in respect of primary culture of fibroblasts and keratinocyte cell line HaCaT.Results. The authors observed pronounced superficial bactericidal effect of TDOLCC+Ag coating in respect of microorganisms of several taxonomic groups independently of their resistance to antibacterial drugs. TDOLCC+Ag coating proved capable to completely prevent microbial biofilm formation by antibiotic resistant clinical isolates of S. aureus and P. aeruginosa. Silvercontaining coating demonstrated mechanical resistance and preservation of close to baseline level of superficial bactericidal activity even after lengthy abrasion treatment. TDOLCC based coatings did not cause any cytotoxic effects. Structure of monolayers formed in cavities coated by TDOLCC+N and TDOLCC+Ag was indistinguishable from the monolayers in cavities of control plates.

scholarly journals Prevalence of carbapenemase-producing Klebsiella pneumonia in Gomel Region of Belarus and their sensitivity to antibiotics, antibiotic combinations, and decontaminants

2020 ◽  
Vol 9 (5-6) ◽  
pp. 671-679
Author(s):  
D. V. Tapalski ◽  
O. I. Savchenko ◽  
N. A. Bonda
Keyword(s):  
Public Health ◽  
Bactericidal Activity ◽  
Antimicrobial Agents ◽  
Bactericidal Effect ◽  
Clinical Isolates ◽  
Klebsiella Pneumonia ◽  
Health Organizations ◽  
Automated Method ◽  
Broth Microdilution Method ◽  
Public Health Organizations

Here, we characterized in public health organizations prevalence of carbapenemase-producing Klebsiella pneumoniae, sensitivity to antimicrobial agents (AMAs), combined antimicrobial agents, and decontaminants. For this, there were selected 58 clinical isolates of K. pneumoniae resistant to carbapenems and/or polymyxins and examined within the microbiological monitoring program. Genes encoding KPC, OXA-48, VIM, IMP, NDM carbapenemases were detected by real-time multiplex PCR. Sensitivity to antimicrobial agents was determined by an automated method on a microbiological VITEK-2 Compact analyzer (bioMérieux, France) and by serial broth microdilution method. Sensitivity to 11 dual antimicrobial agent combinations was determined by a modified method of multiple combination bactericidal antibiotic testing. As a part of combinations, AMAs at pharmacokinetic/pharmacodynamics (PK/PD) threshold concentrations (meropenem — 8 μg/ml, amikacin — 16 μg/ml, levofloxacin — 1 μg/ml, tigecycline — 0.5 μg/ml, phosphomycin — 32 μg/ml, colistin — 2 μg/ml) were tested. Susceptibility to 7 combined decontaminants of different composition was determined by the suspension method. Carbapenemase genes were detected in 22 K. pneumoniae clinical isolates, of which 19 isolates contained a blaOXA-48 gene and 3 isolates — gene blaNDM. Carbapenemase producing K. pneumoniae were identified in 10 Gomel public health organizations and five regional centers of the Gomel region. The majority of such strains were isolated from patients in ICU (63.6%) and surgical departments (27.3%). Tigecycline (100% of the sensitive isolates, МIC50 — 1 μg/ml, MIC90 — 1 μg/ml) and colistin (86.4% of the sensitive isolates, МIC50 — 0.5 μg/ml, MIC90 — 4 μg/ml) exhibited the highest activity against carbapenemase-producing K. pneumoniae, whereas aminopenicillins, cephalosporins, aztreonam, aminoglycosides, fluoroquinolones, chloramphenicol (no sensitive isolates) had exhibited the lowest efficacy. Bactericidal activity of all antibiotic combinations containing colistin was shown against 86.4–95.5% of K. pneumoniae isolates. At least 3 distinct combinations of antimicrobial agents with bactericidal activity were efficient against 21 K. pneumoniae isolates (95.5%). Only 1 bactericidal combination (meropenem–amikacin) was unveiled for one isolate (producer of NDM MBL with MIC of colistin 32 μg/ml). Geksadekon, duacid, oksidez, hlorocid and diajsid exerted a bactericidal effect at 1/4 work dose against all isolates. Duacid, oksidez, hlorocid and diajsid showed bactericidal effect at 1/16 work dose against 95.5–100% isolates. Thus, several decontaminant groups (oxidizing agents, chlorine-containing preparations) were characterized by bactericidal activity against multidrug-resistant and extremely drug-resistant of K. pneumoniae even at 4–16 times lower than recommended concentration.

scholarly journals A Fish Galectin-8 Possesses Direct Bactericidal Activity

2020 ◽  
Vol 22 (1) ◽  
pp. 376
Author(s):  
Tengfei Zhang ◽  
Shuai Jiang ◽  
Li Sun
Keyword(s):  
Bactericidal Activity ◽  
Bacterial Pathogens ◽  
Bactericidal Effect ◽  
Immune Defense ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Animal Cells ◽  
Gram Negative ◽  
Tongue Sole ◽  
Wide Range

Galectins are a family of animal lectins with high affinity for β-galactosides. Galectins are able to bind to bacteria, and a few mammalian galectins are known to kill the bound bacteria. In fish, no galectins with direct bactericidal effect have been reported. In the present study, we identified and characterized a tandem repeat galectin-8 from tongue sole Cynoglossus semilaevis (designated CsGal-8). CsGal-8 possesses conserved carbohydrate recognition domains (CRDs), as well as the conserved HXNPR and WGXEE motifs that are critical for carbohydrate binding. CsGal-8 was constitutively expressed in nine tissues of tongue sole and up-regulated in kidney, spleen, and blood by bacterial challenge. When expressed in HeLa cells, CsGal-8 protein was detected both in the cytoplasm and in the micro-vesicles secreted from the cells. Recombinant CsGal-8 (rCsGal-8) bound to lactose and other carbohydrates in a dose dependent manner. rCsGal-8 bound to a wide range of gram-positive and gram-negative bacteria and was co-localized with the bound bacteria in animal cells. Lactose, fructose, galactose, and trehalose effectively blocked the interactions between rCsGal-8 and different bacteria. Furthermore, rCsGal-8 exerted potent bactericidal activity against some gram-negative bacterial pathogens by directly damaging the membrane and structure of the pathogens. Taken together, these results indicate that CsGal-8 likely plays an important role in the immune defense against some bacterial pathogens by direct bacterial interaction and killing.

scholarly journals Hyperbaric Oxygen Sensitizes Anoxic Pseudomonas aeruginosa Biofilm to Ciprofloxacin

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Mette Kolpen ◽  
Christian J. Lerche ◽  
Kasper N. Kragh ◽  
Thomas Sams ◽  
Klaus Koren ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Hyperbaric Oxygen ◽  
Bactericidal Activity ◽  
Host Response ◽  
Polymorphonuclear Leukocytes ◽  
Bactericidal Effect ◽  
Aerobic Respiration ◽  
Hyperbaric Oxygen Treatment ◽  
Content Type ◽  
Oxygen Treatment

ABSTRACT Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm, which is subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility of biofilms remain unclear, but accumulating evidence suggests that the efficacy of several bactericidal antibiotics is enhanced by stimulation of aerobic respiration of pathogens, while lack of O2 increases their tolerance. In fact, the bactericidal effect of several antibiotics depends on active aerobic metabolism activity and the endogenous formation of reactive O2 radicals (ROS). In this study, we aimed to apply hyperbaric oxygen treatment (HBOT) to sensitize anoxic P. aeruginosa agarose biofilms established to mimic situations with intense O2 consumption by the host response in the cystic fibrosis (CF) lung. Application of HBOT resulted in enhanced bactericidal activity of ciprofloxacin at clinically relevant durations and was accompanied by indications of restored aerobic respiration, involvement of endogenous lethal oxidative stress, and increased bacterial growth. The findings highlight that oxygenation by HBOT improves the bactericidal activity of ciprofloxacin on P. aeruginosa biofilm and suggest that bacterial biofilms are sensitized to antibiotics by supplying hyperbaric O2.

scholarly journals Synergistic Activities of Moxifloxacin Combined with Piperacillin-Tazobactam or Cefepime against Klebsiella pneumoniae, Enterobacter cloacae, and Acinetobacter baumannii Clinical Isolates

2004 ◽  
Vol 48 (3) ◽  
pp. 1055-1057 ◽  
Author(s):  
Rose Jung ◽  
Maroof Husain ◽  
Michael K. Choi ◽  
Douglas N. Fish
Keyword(s):  
Klebsiella Pneumoniae ◽  
Acinetobacter Baumannii ◽  
Bactericidal Activity ◽  
Enterobacter Cloacae ◽  
Clinical Isolates ◽  
Time Kill

ABSTRACT The bactericidal activity of moxifloxacin alone and in combination with cefepime or piperacillin-tazobactam against clinical isolates of Klebsiella pneumoniae, Enterobacter cloacae, and Acinetobacter baumannii was evaluated by using time-kill methods and antimicrobial concentrations of one-half and one times the MIC. Synergy was observed in 58 to 88% of the strains and resulted in bactericidal activity against 60 to 100% of the strains. Combinations including moxifloxacin demonstrated enhanced bactericidal activity compared with that of either agent tested alone.

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