scholarly journals Sensitivity of antibiotic resistant coagulase-negative staphylococci to antiseptic piсloxydin in eye drops Vitabact

2020 ◽  
Author(s):  
Anait Khalatyan ◽  
Maria Budzinskaya ◽  
Ekaterina Kholina ◽  
Marina Strakhovskaya ◽  
Nadezhda Kolyshkina ◽  
...  
Keyword(s):  
High Efficiency ◽  
In Vitro Tests ◽  
Eye Drops ◽  
Bacterial Cells ◽  
Coagulase Negative Staphylococci ◽  
Destructive Effect ◽  
Antibiotic Resistant ◽  
Normal Microflora ◽  
Resistant Strains

Background. Coagulase-negative staphylococci (CNS), primarily Staphylococcus epidermidis, predominate in the normal microflora of the eye. However, due to irrational antibiotic therapy, resistant strains are widely distributed among CNS. Objective. To study the sensitivity of the antibiotic resistant CNS isolates to the antiseptic picloxydine dihydrochloride ("Vitabact"). Methods. Species, sensitivity to antibiotics and antiseptic picloxydine dihydrochloride were determined for 39 isolates of bacteria obtained from the conjunctival swabs. The cells morphology under the influence of antiseptic was studied by electron microscopy. Results. 33 isolates of S. epidermidis (17 sensitive or resistant to drugs of no more than 2 classes of antibiotics and 16 MDR), 2 S. haemolyticus (1 resistant to 2 classes of antibiotics and 1 MDR), 3 S. hominis (1 sensitive and 2 MDR), 1 S. caprae (MDR) were characterized. In vitro tests, the antiseptic picloxydine dihydrochloride showed high efficiency in suppressing the growth of staphylococci regardless of their sensitivity to antibiotics, as well as bactericidal activity at concentration of 31.2 g/ml. In this concentration, the antiseptic had a pronounced destructive effect on the surface structures of bacterial cells. Conclusion. Antiseptic picloxydine dihydrochloride is effective against antibiotic resistant coagulase-negative staphylococci.

Mechanisms involved in effects of antimicrobial peptides, bactenectins ChBac3.4, ChBac5, and mini-ChBac7.5Nb, on bacterial cells

2017 ◽  
pp. 43-50
Author(s):  
О.В. Шамова ◽  
М.С. Жаркова ◽  
П.М. Копейкин ◽  
Д.С. Орлов ◽  
Е.А. Корнева
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Innate Immunity ◽  
Infectious Diseases ◽  
Metabolic Activity ◽  
Capra Hircus ◽  
Bacterial Cells ◽  
Antibiotic Resistant ◽  
Resistant Strains

Антимикробные пептиды (АМП) системы врожденного иммунитета - соединения, играющие важную роль в патогенезе инфекционных заболеваний, так как обладают свойством инактивировать широкий спектр патогенных бактерий, обеспечивая противомикробную защиту живых организмов. В настоящее время АМП рассматриваются как потенциальные соединения-корректоры инфекционной патологии, вызываемой антибиотикорезистентными бактериями (АБР). Цель данной работы состояла в изученим механизмов антибактериального действия трех пептидов, принадлежащих к семейству бактенецинов - ChBac3.4, ChBac5 и mini-ChBac7.5Nb. Эти химически синтезированные пептиды являются аналогами природных пролин-богатых АМП, обнаруженных в лейкоцитах домашней козы Capra hircus и проявляющих высокую антимикробную активность, в том числе и в отношении грамотрицательных АБР. Методы. Минимальные ингибирующие и минимальные бактерицидные концентрации пептидов (МИК и МБК) определяли методом серийных разведений в жидкой питательной среде с последующим высевом на плотную питательную среду. Эффекты пептидов на проницаемость цитоплазматической мембраны бактерий для хромогенного маркера исследовали с использованием генетически модифицированного штамма Escherichia coli ML35p. Действие бактенецинов на метаболическую активность бактерий изучали с применением маркера резазурина. Результаты. Показано, что все исследованные пептиды проявляют высокую антимикробную активность в отношении Escherichia coli ML35p и антибиотикоустойчивых штаммов Escherichia coli ESBL и Acinetobacter baumannii in vitro, но их действие на бактериальные клетки разное. Использован комплекс методик, позволяющих наблюдать в режиме реального времени динамику действия бактенецинов в различных концентрациях (включая их МИК и МБК) на барьерную функцию цитоплазматической мембраны и на интенсивность метаболизма бактериальных клеток, что дало возможность выявить различия в характере воздействия бактенецинов, отличающихся по структуре молекулы, на исследуемые микроорганизмы. Установлено, что действие каждого из трех исследованных бактенецинов в бактерицидных концентрациях отличается по эффективности нарушения целостности бактериальных мембран и в скорости подавления метаболизма клеток. Заключение. Полученная информация дополнит существующие фундаментальные представления о механизмах действия пролин-богатых пептидов врожденного иммунитета, а также послужит основой для биотехнологических исследований, направленных на разработку на базе этих соединений новых антибиотических препаратов для коррекции инфекционных заболеваний, вызываемых АБР и являющимися причинами тяжелых внутрибольничных инфекций. Antimicrobial peptides (AMPs) of the innate immunity are compounds that play an important role in pathogenesis of infectious diseases due to their ability to inactivate a broad array of pathogenic bacteria, thereby providing anti-microbial host defense. AMPs are currently considered promising compounds for treatment of infectious diseases caused by antibiotic-resistant bacteria. The aim of this study was to investigate molecular mechanisms of the antibacterial action of three peptides from the bactenecin family, ChBac3.4, ChBac5, and mini-ChBac7.5Nb. These chemically synthesized peptides are analogues of natural proline-rich AMPs previously discovered by the authors of the present study in leukocytes of the domestic goat, Capra hircus. These peptides exhibit a high antimicrobial activity, in particular, against antibiotic-resistant gram-negative bacteria. Methods. Minimum inhibitory and minimum bactericidal concentrations of the peptides (MIC and MBC) were determined using the broth microdilution assay followed by subculturing on agar plates. Effects of the AMPs on bacterial cytoplasmic membrane permeability for a chromogenic marker were explored using a genetically modified strain, Escherichia coli ML35p. The effect of bactenecins on bacterial metabolic activity was studied using a resazurin marker. Results. All the studied peptides showed a high in vitro antimicrobial activity against Escherichia coli ML35p and antibiotic-resistant strains, Escherichia coli ESBL and Acinetobacter baumannii, but differed in features of their action on bacterial cells. The used combination of techniques allowed the real-time monitoring of effects of bactenecin at different concentrations (including their MIC and MBC) on the cell membrane barrier function and metabolic activity of bacteria. The differences in effects of these three structurally different bactenecins on the studied microorganisms implied that these peptides at bactericidal concentrations differed in their capability for disintegrating bacterial cell membranes and rate of inhibiting bacterial metabolism. Conclusion. The obtained information will supplement the existing basic concepts on mechanisms involved in effects of proline-rich peptides of the innate immunity. This information will also stimulate biotechnological research aimed at development of new antibiotics for treatment of infectious diseases, such as severe in-hospital infections, caused by antibiotic-resistant strains.

scholarly journals Species-Specific Sensitivity of Coagulase-Negative Staphylococci to Single Antibiotics and Their Combinations

2011 ◽  
Vol 60 (2) ◽  
pp. 155-161 ◽  
Author(s):  
GRAŻYNA SZYMAŃSKA ◽  
MAGDALENA SZEMRAJ ◽  
ELIGIA M. SZEWCZYK
Keyword(s):  
University Hospital ◽  
Hospital Environment ◽  
Beta Lactam ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Beta Lactam Antibiotics ◽  
Resistant Strains ◽  
Staphylococcus Hominis ◽  
Species Specific

The activity of beta-lactam antibiotics (oxacillin, cloxacillin, cephalotin), vancomycin, gentamicin and rifampicin applied in vitro individually and in combination against 37 nosocomial methicillin-resistant strains of coagulase-negative staphylococci (CNS) was assessed to demonstrate the heterogeneity of this group of bacteria and estimate the chance of the efficacy of such therapy. The strains belonged to four species: Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus cohnii, Staphylococcus hominis. They originated from a hospital environment and from the skin of medical staff of the intensive care unit of a paediatric ward at a university hospital. All strains were methicillin-resistant, according to CLSI standards, but individual strains differed in MIC(ox) values. Susceptibility to other tested antibiotics was also characteristic for the species. The increased susceptibility to antibiotics in combinations, tested by calculating the fractional inhibitory concentration (FIC) index, concerned 26 out of 37 investigated strains and it was a feature of a particular species. Combinations of vancomycin and cephalotin against S. epidermidis and oxacillin with vancomycin were significant, as well as cephalotin and rifampicin in growth inhibition of multiresistant S. haemolyticus strains.

scholarly journals TSPphg Lysin from the Extremophilic Thermus Bacteriophage TSP4 as a Potential Antimicrobial Agent against Both Gram-Negative and Gram-Positive Pathogenic Bacteria

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 192 ◽  
Author(s):  
Feng Wang ◽  
Xinyu Ji ◽  
Qiupeng Li ◽  
Guanling Zhang ◽  
Jiani Peng ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Infection Model ◽  
Bacterial Cells ◽  
Skin Damage ◽  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative

New strategies against antibiotic-resistant bacterial pathogens are urgently needed but are not within reach. Here, we present in vitro and in vivo antimicrobial activity of TSPphg, a novel phage lysin identified from extremophilic Thermus phage TSP4 by sequencing its whole genome. By breaking down the bacterial cells, TSPphg is able to cause bacteria destruction and has shown bactericidal activity against both Gram-negative and Gram-positive pathogenic bacteria, especially antibiotic-resistant strains of Klebsiella pneumoniae, in which the complete elimination and highest reduction in bacterial counts by greater than 6 logs were observed upon 50 μg/mL TSPphg treatment at 37 °C for 1 h. A murine skin infection model further confirmed the in vivo efficacy of TSPphg in removing a highly dangerous and multidrug-resistant Staphylococcus aureus from skin damage and in accelerating wound closure. Together, our findings may offer a therapeutic alternative to help fight bacterial infections in the current age of mounting antibiotic resistance, and to shed light on bacteriophage-based strategies to develop novel anti-infectives.

scholarly journals In vitro Antimicrobial Activity of Acne Drugs Against Skin-Associated Bacteria

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mark A. T. Blaskovich ◽  
Alysha G. Elliott ◽  
Angela M. Kavanagh ◽  
Soumya Ramu ◽  
Matthew A. Cooper
Keyword(s):  
Antimicrobial Activity ◽  
Resistant Bacteria ◽  
Microbial Infection ◽  
Antibiotic Resistant ◽  
Drug Resistant Bacteria ◽  
Cutibacterium Acnes ◽  
Common Skin ◽  
Sebum Production ◽  
Resistant Strains

Abstract Acne is a common skin affliction that involves excess sebum production and modified lipid composition, duct blockage, colonization by bacteria, and inflammation. Acne drugs target one or more of these steps, with antibiotics commonly used to treat the microbial infection for moderate to severe cases. Whilst a number of other acne therapies are purported to possess antimicrobial activity, this has been poorly documented in many cases. We conducted a comparative analysis of the activity of common topical acne drugs against the principal etiological agent associated with acne: the aerotolerant anaerobic Gram-positive organism Propionibacterium acnes (recently renamed as Cutibacterium acnes). We also assessed their impact on other bacteria that could also be affected by topical treatments, including both antibiotic-sensitive and antibiotic-resistant strains, using broth microdilution assay conditions. Drugs designated specifically as antibiotics had the greatest potency, but lost activity against resistant strains. The non-antibiotic acne agents did possess widespread antimicrobial activity, including against resistant strains, but at substantially higher concentrations. Hence, the antimicrobial activity of non-antibiotic acne agents may provide protection against a background of increased drug-resistant bacteria.

scholarly journals Comparative fitness analysis of D-cycloserine resistant mutants reveals both fitness-neutral and high-fitness cost genotypes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Dimitrios Evangelopoulos ◽  
Gareth A. Prosser ◽  
Angela Rodgers ◽  
Belinda M. Dagg ◽  
Bhagwati Khatri ◽  
...  
Keyword(s):  
Biological Factor ◽  
Resistance Mutations ◽  
Compensatory Mechanisms ◽  
Medical Problems ◽  
Antibiotic Resistant ◽  
Clinical Resistance ◽  
Resistant Strains ◽  
Rate Of Emergence ◽  
Fitness Analysis

Abstract Drug resistant infections represent one of the most challenging medical problems of our time. D-cycloserine is an antibiotic used for six decades without significant appearance and dissemination of antibiotic resistant strains, making it an ideal model compound to understand what drives resistance evasion. We therefore investigated why Mycobacterium tuberculosis fails to become resistant to D-cycloserine. To address this question, we employed a combination of bacterial genetics, genomics, biochemistry and fitness analysis in vitro, in macrophages and in mice. Altogether, our results suggest that the ultra-low rate of emergence of D-cycloserine resistance mutations is the dominant biological factor delaying the appearance of clinical resistance to this antibiotic. Furthermore, we also identified potential compensatory mechanisms able to minimize the severe fitness costs of primary D-cycloserine resistance conferring mutations.

scholarly journals In Vitro Activities of RWJ-54428 (MC-02,479) against Multiresistant Gram-Positive Bacteria

2001 ◽  
Vol 45 (5) ◽  
pp. 1422-1430 ◽  
Author(s):  
Suzanne Chamberland ◽  
Johanne Blais ◽  
Monica Hoang ◽  
Cynthia Dinh ◽  
Dylan Cotter ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Penicillin G ◽  
Significant Activity ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Level Of Activity ◽  
Resistant Strains ◽  
High Level

ABSTRACT RWJ-54428 (MC-02,479) is a new cephalosporin with a high level of activity against gram-positive bacteria. In a broth microdilution susceptibility test against methicillin-resistant Staphylococcus aureus (MRSA), RWJ-54428 was as active as vancomycin, with an MIC at which 90% of isolates are inhibited (MIC90) of 2 μg/ml. For coagulase-negative staphylococci, RWJ-54428 was 32 times more active than imipenem, with an MIC90 of 2 μg/ml. RWJ-54428 was active against S. aureus, Staphylococcus epidermidis, and Staphylococcus haemolyticus isolates with reduced susceptibility to glycopeptides (RWJ-54428 MIC range, ≤0.0625 to 1 μg/ml). RWJ-54428 was eight times more potent than methicillin and cefotaxime against methicillin-susceptible S. aureus (MIC90, 0.5 μg/ml). For ampicillin-susceptible Enterococcus faecalis (including vancomycin-resistant and high-level aminoglycoside-resistant strains), RWJ-54428 had an MIC90 of 0.125 μg/ml. RWJ-54428 was also active against Enterococcus faecium, including vancomycin-, gentamicin-, and ciprofloxacin-resistant strains. The potency against enterococci correlated with ampicillin susceptibility; RWJ-54428 MICs ranged between ≤0.0625 and 1 μg/ml for ampicillin-susceptible strains and 0.125 and 8 μg/ml for ampicillin-resistant strains. RWJ-54428 was more active than penicillin G and cefotaxime against penicillin-resistant, -intermediate, and -susceptible strains ofStreptococcus pneumoniae (MIC90s, 0.25, 0.125, and ≤0.0625 μg/ml, respectively). RWJ-54428 was only marginally active against most gram-negative bacteria; however, significant activity was observed against Haemophilus influenzae andMoraxella catarrhalis (MIC90s, 0.25 and 0.5 μg/ml, respectively). This survey of the susceptibilities of more than 1,000 multidrug-resistant gram-positive isolates to RWJ-54428 indicates that this new cephalosporin has the potential to be useful in the treatment of infections due to gram-positive bacteria, including strains resistant to currently available antimicrobials.

scholarly journals In Vitro Antibacterial Activities of DQ-113, a Potent Quinolone, against Clinical Isolates

2002 ◽  
Vol 46 (3) ◽  
pp. 904-908 ◽  
Author(s):  
Mayumi Tanaka ◽  
Emi Yamazaki ◽  
Megumi Chiba ◽  
Kiyomi Yoshihara ◽  
Takaaki Akasaka ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Moraxella Catarrhalis ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Clinical Isolates ◽  
Coagulase Negative Staphylococci ◽  
Vancomycin Resistant Enterococci ◽  
Resistant Strains ◽  
Vancomycin Resistant

ABSTRACT The antibacterial activity of DQ-113, formerly D61-1113, was compared with those of antibacterial agents currently available. MICs at which 90% of the isolates tested are inhibited (MIC90s) of DQ-113 against clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus and methicillin-susceptible and -resistant coagulase-negative staphylococci were 0.03, 0.008, 0.03, and 0.06 μg/ml, respectively. Moreover, DQ-113 showed the most potent activity against ofloxacin-resistant and methicillin-resistant S. aureus, with a MIC90 of 0.25μg/ml. DQ-113 inhibited the growth of all strains of Streptococcus pneumoniae, including penicillin-resistant strains, and Streptococcus pyogenes at 0.06 μg/ml, and DQ-113 was more active than the other quinolones tested against Enterococcus faecalis and Enterococcus faecium with MIC90s of 0.25 and 2 μg/ml, respectively. Against vancomycin-resistant enterococci, DQ-113 showed the highest activity among the reference compounds, with a MIC range from 0.25 to 2 μg/ml. DQ-113 also showed a potent activity against Haemophilus influenzae, including ampicillin-resistant strains (MIC90, 0.015 μg/ml), and Moraxella catarrhalis (MIC90, 0.03 μg/ml). The activity of DQ-113 was roughly comparable to that of levofloxacin against all species of Enterobacteriaceae. The MICs of DQ-113 against ofloxacin-susceptible Pseudomonas aeruginosa ranged from 0.25 to 2 μg/ml, which were four times higher than those of ciprofloxacin. From these results, DQ-113 showed the most potent activity against gram-positive pathogens among antibacterial agents tested.

scholarly journals Antigiardial Effect of Kramecyne in Experimental Giardiasis

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Leticia Eligio-García ◽  
Elida Pontifez-Pablo ◽  
Salúd Pérez-Gutiérrez ◽  
Enedina Jiménez-Cardoso
Keyword(s):  
Side Effects ◽  
High Efficiency ◽  
Morphological Changes ◽  
Lethal Dose ◽  
Expression Of Genes ◽  
Antigiardial Activity ◽  
Resistant Strains ◽  
Polymerase Chain

A variety of drugs are used in giardiasis treatment with different levels of efficiency, presence of side effects, and even formation of resistant strains, so that it is important to search new only-one-dose treatments with high efficiency and less side effects. Kramecyne, an anti-inflammatory compound isolated from methanolic extract ofKrameria cytisoides, does not present toxicity, even at doses of 5,000 mg/kg. The objective was to determine the antigiardial effect of kramecyne overGiardia intestinalis in vitroandin vivoand analyze the expression of genes ERK1, ERK2, and AK on kramecyne treated trophozoites by Real Time Polymerase Chain Reaction (RTPCR). The median lethal dose (LD50) was 40 μg/mL and no morphological changes were observed by staining with blue trypan and light microscopy; experimental gerbil infection was eliminated with 320 μg/Kg of weight. After treatment there were no differences between intestines from treated and untreated gerbils. Kramecyne did not have significant effect over ERK1 and AK, but there are differences in ERK2 expression (p=0.04). Results show antigiardial activity of kramecyne; however the mode of action is still unclear and the evaluation of ultrastructural damage and expressed proteins is an alternative of study to understand the action mechanism.

scholarly journals MODERN AND RAPID METHODS FOR TOXICOLOGICAL ANALYSIS OF FOODSTUFFS WITH BACTERIAL CONTAMINATION

2018 ◽  
Vol 6 (1) ◽  
pp. 69-78
Author(s):  
Rozalina Yordanova ◽  
Katya Kichukova
Keyword(s):  
Food Poisoning ◽  
Rapid Test ◽  
In Vitro Tests ◽  
Bacterial Cells ◽  
Foodborne Illnesses ◽  
Toxin Genes ◽  
Large Numbers ◽  
Immunological Tests

Foodborne illnesses are a widespread problem throughout the world. Food poisoning due to bacterial toxins can be caused by the ingestion of exotoxins which are preformed in the food, or by the ingestion of food containing large numbers of bacterial cells which then release endotoxins in the gastrointestinal tract. Early methods for the assay of bacteria toxins were based on in vivo or in vitro tests. Later, immunological tests were developed based on techniques such as gel diffusion. Different types of methods have been developed for the detection of toxin genes and their toxic products. These methods include the detection of toxin genes by amplification methods and hybridization probing. There are now a number of rapid test kits available which give results within hours and are much simpler to perform and interpret than bioassays.

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