tetracycline and Hemolysis

Topics: Anti-Bacterial Agents; Bacteria; Escherichia coli; Haemophilus influenzae; Hemolysis; Humans; Immunosuppression Therapy; Klebsiella; Microbial Sensitivity Tests; Neisseria gonorrhoeae; Neisseria meningitidis; Penicillin Resistance; Penicillins; Proteus; Pseudomonas; Serratia; Serratia marcescens; Staphylococcus; Streptococcus; Streptococcus pneumoniae; Sulfonamides; Tetracycline

Topics: Allosteric Regulation; Allosteric Site; Anti-Bacterial Agents; Bacterial Proteins; Binding Sites; Drug Design; Drug Resistance, Multiple; Gram-Negative Bacteria; Gram-Positive Bacteria; Hemolysis; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Molecular Docking Simulation; Naphthalimides; Oxidative Stress; Oximes; Penicillin-Binding Proteins; Structure-Activity Relationship

Members of the genus Aeromonas are ubiquitous in nature and have increasingly been implicated in numerous diseases of humans and other animal taxa. Although some species of aeromonads are human pathogens, their presence, density, and relative abundance are rarely considered in assessing water quality. The objectives of this study were to identify Aeromonas species within Lake Erie, determine their antibiotic resistance patterns, and assess their potential pathogenicity. Aeromonas strains were isolated from Lake Erie water by use of Aeromonas selective agar with and without tetracycline and ciprofloxacin. All isolates were analyzed for hemolytic ability and cytotoxicity against human epithelial cells and were identified to the species level by using 16S rRNA gene restriction fragment length polymorphisms and phylogenetic analysis based on gyrB gene sequences. A molecular virulence profile was identified for each isolate, using multiplex PCR analysis of six virulence genes. We demonstrated that Aeromonas comprised 16% of all culturable bacteria from Lake Erie. Among 119 Aeromonas isolates, six species were identified, though only two species (Aeromonas hydrophila and A. veronii) predominated among tetracycline- and ciprofloxacin-resistant isolates. Additionally, both of these species demonstrated pathogenic phenotypes in vitro. Virulence gene profiles demonstrated a high prevalence of aerolysin and serine protease genes among A. hydrophila and A. veronii isolates, a genetic profile which corresponded with pathogenic phenotypes. Together, our findings demonstrate increased antibiotic resistance among potentially pathogenic strains of aeromonads, illustrating an emerging potential health concern.

Topics: Aeromonas; Anti-Bacterial Agents; Cell Survival; Ciprofloxacin; DNA Gyrase; Drug Resistance, Bacterial; Epithelial Cells; Hemolysis; Lakes; Phylogeny; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Tetracycline; Virulence Factors

Our previous studies revealed that alpha-melanocyte stimulating hormone (α-MSH) is strongly active against Staphylococcus aureus (S. aureus) including methicillin resistant S. aureus (MRSA). Killing due to α-MSH occurred by perturbation of the bacterial membrane. In the present study, we investigated the in vitro synergistic potential of α-MSH with five selected conventional antibiotics viz., oxacillin (OX), ciprofloxacin (CF), tetracycline (TC), gentamicin (GM) and rifampicin (RF) against a clinical MRSA strain which carried a type III staphylococcal cassette chromosome mec (SCCmec) element and belonged to the sequence type (ST) 239. The strain was found to be highly resistant to OX (minimum inhibitory concentration (MIC) = 1024 µg/ml) as well as to other selected antimicrobial agents including α-MSH. The possibility of the existence of intracellular target sites of α-MSH was evaluated by examining the DNA, RNA and protein synthesis pathways. We observed a synergistic potential of α-MSH with GM, CF and TC. Remarkably, the supplementation of α-MSH with GM, CF and TC resulted in ≥ 64-, 8- and 4-fold reductions in their minimum bactericidal concentrations (MBCs), respectively. Apart from membrane perturbation, in this study we found that α-MSH inhibited ≈ 53% and ≈ 47% DNA and protein synthesis, respectively, but not RNA synthesis. Thus, the mechanistic analogy between α-MSH and CF or GM or TC appears to be the reason for the observed synergy between them. In contrast, α-MSH did not act synergistically with RF which may be due to its inability to inhibit RNA synthesis (<10%). Nevertheless, the combination of α-MSH with RF and OX showed an enhanced killing by ≈ 45% and ≈ 70%, respectively, perhaps due to the membrane disrupting properties of α-MSH. The synergistic activity of α-MSH with antibiotics is encouraging, and promises to restore the lost potency of discarded antibiotics.

Topics: 3T3 Cells; alpha-MSH; Animals; Anti-Bacterial Agents; Bacterial Proteins; Cell Survival; Ciprofloxacin; DNA, Bacterial; Dose-Response Relationship, Drug; Drug Synergism; Fibroblasts; Gentamicins; Hemolysis; Humans; Methicillin-Resistant Staphylococcus aureus; Mice; Microbial Sensitivity Tests; Microbial Viability; Oxacillin; Rifampin; RNA, Bacterial; Tetracycline

Intracellular bacterial infections are recurrent, persistent and are difficult to treat because of poor penetration and limited availability of antibiotics within macrophages and epithelial cells. We developed biocompatible, 200 nm sized tetracycline encapsulated O-carboxymethyl chitosan nanoparticles (Tet-O-CMC Nps) via ionic gelation for its sustained delivery of Tet into cells. S. aureus binds and aggregates with Tet-O-CMC Nps increasing drug concentrations at the infection site. Tet-O-CMC Nps were sixfold more effective in killing intracellular S. aureus compared to Tet alone in HEK-293 and differentiated THP1 macrophage cells proving it to be an efficient nanomedicine to treat intracellular S. aureus infections.

Topics: Anti-Bacterial Agents; Biocompatible Materials; Capsules; Chitosan; Drug Carriers; Endocytosis; Gels; HEK293 Cells; Hemolysis; Humans; Intracellular Space; Nanoparticles; Particle Size; Platelet Activation; Staphylococcus aureus; Tetracycline

We investigated the potency, selectivity, and mode of action of the oligo-acyl-lysine (OAK) NC(12)-2 beta(12), which was recently suggested to represent the shortest OAK sequence that retains nonhemolytic antibacterial properties. A growth inhibition assay against a panel of 48 bacterial strains confirmed that NC(12)-2 beta(12) exerted potent activity against gram-positive bacteria while exhibiting negligible hemolysis up to at least 100 times the MIC. Interestingly, NC(12)-2 beta(12) demonstrated a bacteriostatic mode of action, unlike previously described OAKs that were bactericidal and essentially active against gram-negative bacteria only. The results of various experiments with binding to model phospholipid membranes correlated well with those of the cytotoxicity experiments and provided a plausible explanation for the observed activity profile. Thus, surface plasmon resonance experiments performed with model bilayers revealed high binding affinity to a membrane composition that mimicked the plasma membrane of staphylococci (global affinity constant [K(app)], 3.7 x 10(6) M(-1)) and significantly lower affinities to mimics of Escherichia coli or red blood cell cytoplasmic membranes. Additional insertion isotherms and epifluorescence microscopy experiments performed with model Langmuir monolayers mimicking the outer leaflet of plasma membranes demonstrated the preferential insertion of NC(12)-2 beta(12) into highly anionic membranes. Finally, we provide mechanistic studies in support of the view that the bacteriostatic effect resulted from a relatively slow process of plasma membrane permeabilization involving discrete leakage of small solutes, such as intracellular ATP. Collectively, the data point to short OAKs as a potential source for new antibacterial compounds that can selectively affect the growth of gram-positive bacteria while circumventing potential adverse effects linked to lytic compounds.

Topics: Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Cell Membrane; Erythrocytes; Escherichia coli; Gram-Positive Bacteria; Hemolysis; Humans; Microscopy, Fluorescence; Staphylococcus; Surface Plasmon Resonance

Series of short amino terminal modified cationic peptides were designed and synthesized. All of the synthesized compounds were tested against gram-positive as well as gram-negative bacterial strain. Some of the compounds exhibit potent antibacterial activity and no hemolytic activity even at high dose level (1000 microg/mL) in mammalian erythrocytes was observed.

Topics: Anti-Bacterial Agents; Gram-Positive Bacteria; Hemolysis; Humans; Microbial Sensitivity Tests; Peptides

The activities of ampicillin, amoxycillin-clavulanic acid, gentamicin, tetracycline, nalidixic acid, ciprofloxacin, pefloxacin and trovafloxacin against 207 consecutive clinical isolates of Escherichia coli were determined. Fifty-six (27.3%) isolates were haemolytic. The percentages of resistance to quinolones and tetracycline, but not to other agents, among haemolytic isolates were significantly lower (P < 0.05) than among non-haemolytic isolates. Ciprofloxacin-resistant mutants obtained from ciprofloxacin-susceptible haemolytic isolates still produced haemolysis. It is concluded that most quinolone-resistant clinical isolates of E. coli are non-haemolytic, although haemolysis is produced by quinolone-resistant mutants derived from haemolytic quinolone-susceptible strains.

Topics: Amoxicillin; Ampicillin; Animals; Anti-Infective Agents; Ciprofloxacin; Clavulanic Acid; Drug Resistance, Microbial; Escherichia coli; Fluoroquinolones; Gentamicins; Hemolysin Proteins; Hemolysis; Humans; Microbial Sensitivity Tests; Nalidixic Acid; Naphthyridines; Pefloxacin; Tetracycline

An in vitro model was employed to study the potential role of streptococcal extra-cellular products, rich in streptolysin O, in cellular injury as related to streptococcal infections and post-streptococcal sequelae. Extra-cellular products (EXPA) rich in streptolysin O were isolated from type 4, group A hemolytic streptococci grown in a chemostat, in a synthetic medium. EXPA induced moderate cytopathogenic changes in monkey kidney epithelial cells and in rat heart cells pre-labeled with 3H-arachidonate. However very strong toxic effects were induced when EXP was combined with oxidants (glucose oxides generated H2O2, AAPH-induced peroxyl radical (ROO.), NO generated by sodium nitroprusside) and proteinases (plasmin, trypsin). Cell killing was distinctly synergistic in nature. Cell damage induced by the multi-component cocktails was strongly inhibited either by micromolar amounts of gamma globulin, and Evan's blue which neutralized SLO activity, by tetracycline, trasylol (aprotinin), epsilon amino caproic acid and by soybean trypsin inhibitor, all proteinase inhibitors as well as by a non-penetrating PLA2 inhibitor A. The results suggest that fasciitis, myositis and sepsis resulting from infections with hemolytic streptococci might be caused by a coordinated 'cross-talk' among microbial, leukocyte and additional host-derived pro-inflammatory agents. Since attempts to prolong lives of septic patients by the exclusive administration of single antagonists invariably failed, it is proposed that the administration of 'cocktails' of putative inhibitors against major pro-inflammatory agonizes generated in inflammation and infection might protect against the deleterious effects caused by the biochemical and pharmacological cascades which are known to be activated in sepsis.

Topics: Animals; Anti-Bacterial Agents; Antioxidants; Aprotinin; Arachidonic Acid; Cells, Cultured; Endopeptidases; Epithelial Cells; Erythrocytes; Evans Blue; gamma-Globulins; Haplorhini; Hemolysis; Humans; Hydrogen Peroxide; Myocardium; Oxidants; Phospholipases A; Phospholipases A2; Rats; Shock, Septic; Streptococcal Infections; Streptococcus pyogenes; Streptolysins; Tetracycline

The distribution of serotypes of beta-hemolytic streptococci was examined in 718 periodontitis patients. Subgingival samples were obtained with paper points from the 3 deepest lesions in each patient, transported in VMGA III, plated onto brucella agar with 5% sheep blood and incubated anaerobically for 7 days. Serotyping and speciation were performed with Meritec-Strep Beta-Hemolytic Streptococcus Grouping Set and the Analytab 20S Streptococcus System. Beta-hemolytic streptococci were recovered from 33.7% of patients and averaged 10.5% of the total viable counts in culture-positive subjects. The organisms occurred with higher prevalence in patients 35 years or older than in younger patients. The predominant serotypes were F (62.9%), non-typeable (18.1%), B (6.9%), C (6.9%) and G (5.2%). 100% of beta-hemolytic streptococci were sensitive to penicillin, but less than 5% were sensitive to tetracycline, metronidazole or ciprofloxacin. Beta-hemolytic streptococci may contribute to inflammatory periodontal disease and may interfere with healing after therapy.

Topics: Adolescent; Adult; Age Factors; Aged; Ciprofloxacin; Colony Count, Microbial; Cross-Sectional Studies; Female; Hemolysis; Humans; Male; Metronidazole; Microbial Sensitivity Tests; Middle Aged; Penicillin G; Periodontitis; Prevalence; Serotyping; Streptococcus; Tetracycline

Species differences in red blood cell susceptibility to the photohemolytic agents chlorpromazine, menadione and tetracycline were examined in mouse, rat, dog, and human blood. Menadione and tetracycline (25 microM) hemolyzed mouse but not dog, rat, or human red blood cells (RBC) when irradiated with UV light but not in the dark. Chlorpromazine (25 microM) produced a photohemolytic response in all four species with mouse and rat RBC lysing fastest followed by human then dog cells. Investigations into the nature of these species differences suggested that the size of mouse RBC may contribute to its high sensitivity to photohemolytic agents. An investigation of the effect of UV light on key antioxidant enzymes revealed species differences in enzyme inactivation. These data suggest that mouse RBC may be particularly vulnerable to phototoxic agents, especially those compounds which produce active oxygen species and, therefore, may prove more useful than human RBC as a model for predicting phototoxic potential of some chemical entities.

Topics: Animals; Chlorpromazine; Dogs; Erythrocytes; Free Radical Scavengers; Hemolysis; Humans; In Vitro Techniques; Mice; Photochemistry; Rats; Species Specificity; Tetracycline; Ultraviolet Rays; Vitamin K

Streptococcus faecalis strain JH1 harbors two conjugative plasmids: pJH1, an R plasmid mediating resistance to kanamycin, streptomycin, gentamicin, erythromycin, and tetracycline, and pJH2, a hemolysin-bacteriocin plasmid. Studies of plasmid-cured derivatives of strain JH1 and of transconjugates obtained after mixed incubation of JH1 with the plasmid-free S. faecalis strain JH2-2 revealed the presence of two tetracycline resistance determinants in strain JH1. One determinant mediated constitutive resistance to 40 micrograms of tetracycline per ml and was associated with plasmid pJH1. The second determinant, either on the chromosome of strain JH1 or on an undetectable plasmid, was inducible by tetracycline and enabled the host strain, in the absence of pJH1, to grow in the presence of 80 micrograms of tetracycline per ml. One transconjugant, strain DL172, was resistant to 80 micrograms of tetracycline per ml, sensitive to kanamycin, streptomycin, and erythromycin, and hemolytic in the presence, but not in the absence, of tetracycline. A single plasmid, pDL172, from this strain consisted of plasmid pJH2 and a 17.8-kilobase segment of DNA homologous to total cell DNA from strain JH1 but did not contain plasmid pJH1. Whether the addition of heterologous DNA to plasmid pJH2 occurred by translocation of a 17.8-kilobase tetracycline resistance transposon or by classical recombination with pJH2 has not been determined.

Topics: Base Sequence; Chromosomes, Bacterial; Conjugation, Genetic; Enterococcus faecalis; Gene Expression Regulation; Genes, Bacterial; Hemolysis; Nucleic Acid Hybridization; R Factors; Recombination, Genetic; Tetracycline

Topics: Acetazolamide; Adult; Animals; Erythrocyte Membrane; Erythrocytes; Hemolysis; Histamine; Humans; In Vitro Techniques; Male; Procaine; Salicylates; Sheep; Tetracycline; Urethane

Topics: Bacteriophages; DNA Transposable Elements; Escherichia coli; F Factor; Hemolysis; Kanamycin; Penicillin Resistance; R Factors; Tetracycline; Transduction, Genetic

Combinations of certain antibiotics and normal human serum at concentrations at which there was no killing by the agents when used alone were found to be bactericidal for Escherichia coli K-12 cells. This effect was observed with tetracycline, streptomycin (SM), trimethoprim, and ampicillin, but not with chloramphenicol or nalidixic acid. Synergy between SM and human serum was also observed against four of nine smooth strains of E. coli. A plasmid-bearing strain of E. coli K-12 was also killed by combinations of tetracycline or SM plus serum, even though the plasmid conferred resistance to tetracycline and SM. Evidence is presented that the synergy between antibiotics and serum is due to a complement-mediated effect on the bacterial cells that makes the cells more susceptible to the bactericidal effects of the antibiotics.

Topics: Anti-Bacterial Agents; Blood Bactericidal Activity; Complement System Proteins; Escherichia coli; Hemolysis; Humans; In Vitro Techniques; R Factors; Streptomycin; Tetracycline; Time Factors

Topics: Ampicillin; Anti-Bacterial Agents; Hemolysis; Penicillin G; Penicillin Resistance; Species Specificity; Streptococcus; Tetracycline

The comparative performance of three presumptive identification tests for group B haemolytic streptococci was investigated, using 371 different clinical isolates of group B streptococci. Hippurate was hydrolysed by 96-1%, the CAMP reaction was positive in 95-0%, and pigment was produced by 97-3%. A combination of any two tests would have detected over 99-8%. On bile esculin agar 99-0% were able to grow, but non hydrolysed esculin; 5-1% were susceptible to bacitracin. The minimum inhibitory concentrations of five antibiotics for 279 group B streptococci were determined. All were susceptible to penicillin G, ampicillin, cephalothin, and erythromycin, while 80% were resistant to tetracycline. The MIC distributions were independent of the results of any identification test.

Topics: Ampicillin; Anti-Bacterial Agents; Bacitracin; Cephalothin; Erythrocytes; Erythromycin; Esculin; Hemolysis; Hippurates; Humans; Hydrolysis; Microbial Sensitivity Tests; Penicillin G; Pigmentation; Streptococcus agalactiae; Tetracycline

A study was made of 111 strains of plasma-negative spathylococci isolated from the blood, pleural fluid, urine, and exudate of the abdominal cavity of 30 patients. The studies were carried out by 18 criteria. A variety of biological properties and signs characteristic of pathogenic staphylococci (hemolytic activity, anaerobic splitting of mannite, the presence of phosphatase, lysozyme, protease, alpha-toxin, fibrinolysin) were noted. A high resistance to tetracycline and penicillin was found in the strains isolated from the blood and the pleural cavity.

Topics: Animals; Ascitic Fluid; Bacteriophage Typing; Bacteriuria; Cross Infection; Erythrocytes; Fibrinolysin; Hemolysis; Humans; Mannitol; Muramidase; Penicillin Resistance; Penicillins; Phospholipases; Phosphoric Monoester Hydrolases; Pleural Effusion; Pyelonephritis; Rabbits; Sepsis; Staphylococcal Infections; Staphylococcus; Surgical Procedures, Operative; Tetracycline; Toxins, Biological

Topics: Amino Acids; Bacitracin; Carbohydrate Metabolism; Chloramphenicol; Culture Media; Erythromycin; Fermentation; Hemolysis; Lipid Metabolism; Listeria monocytogenes; Neomycin; Tetracycline

Topics: Adjuvants, Immunologic; Animals; Antigen-Antibody Reactions; Endotoxins; Erythrocytes; Female; Hemolysis; Hemolytic Plaque Technique; Immunization; Male; Sheep; Tetracycline

Topics: Anilides; Anthracenes; Buffers; Cell Membrane; Erythrocytes; Hemolysis; Humans; Hydrogen-Ion Concentration; Methods; Osmotic Fragility; Phenothiazines; Photolysis; Porphyrins; Radiation Effects; Salicylates; Solvents; Spectrophotometry; Sulfonamides; Tetracycline; Ultraviolet Rays

Topics: Adolescent; Adult; Cholesterol; Circadian Rhythm; Colorimetry; Female; Hemolysis; Humans; Hypercholesterolemia; Lipids; Magnesium; Menstruation; Methods; Muscles; Neural Conduction; Nutritional Physiological Phenomena; Seasons; Spectrophotometry; Tetracycline

Topics: Agar; Animals; Anti-Bacterial Agents; Chloramphenicol; Colistin; Diffusion; Dihydrostreptomycin Sulfate; Drug Resistance, Microbial; Escherichia coli; Escherichia coli Infections; Furazolidone; Hemolysis; Kanamycin; Microbial Sensitivity Tests; Neomycin; Paper; Serotyping; Swine; Swine Diseases; Tetracycline

Topics: Anti-Bacterial Agents; Cephalothin; Chloramphenicol; Drug Synergism; Hemolysis; Penicillins; Protein Biosynthesis; Tetracycline; Vibrio

Mycoplasma strains (B1, B2, CS, and S1A) were isolated from the saliva of normal cats. These were compared with a strain (CO) isolated from the eye of a cat with severe conjunctivitis. On the basis of morphology, biochemical reactions, and antigenic composition, two distinct species were recognizable. Strains CO, B1, and B2 were antigenically unrelated to the other species tested; strains CS and S1A possessed antigenic components in common with Mycoplasma arthritidis, M. salivarium, M. hominis, type 1, and M. orale, types 1 and 2. It was tentatively suggested that the two cat species be called M. felis and M. gateae, respectively.

Topics: Animals; Antigens; Cats; Chloramphenicol; Complement Fixation Tests; Conjunctivitis; Dihydrostreptomycin Sulfate; Erythromycin; Hemolysis; Immune Sera; Immunodiffusion; Lincomycin; Mycoplasma; Neomycin; Novobiocin; Rats; Saliva; Tetracycline

Topics: Agglutination Tests; Animals; Antibody Formation; Hemolysis; Leptospira interrogans; Leptospirosis; Rats; Tetracycline

Topics: Aminobenzoates; Animals; Blood; Chick Embryo; Chloramphenicol; Chlortetracycline; Cycloserine; Erythromycin; Hemolysis; In Vitro Techniques; Mice; Penicillins; Rickettsia; Rickettsia prowazekii; Sheep; Tetracycline

Topics: Anti-Bacterial Agents; Chloramphenicol; Drug Resistance, Microbial; Hemolysis; Mitomycins; Mutation; Penicillin Resistance; Radiation Effects; Streptococcus pyogenes; Streptomycin; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Bacteriophage Typing; Chloramphenicol; Chlortetracycline; Dogs; Erythromycin; Hemolysis; In Vitro Techniques; Neomycin; Oxytetracycline; Penicillins; Staphylococcus; Streptomycin; Tetracycline

Topics: Abortion, Criminal; Abortion, Septic; Anti-Bacterial Agents; Anuria; Biopsy; Criminals; Curettage; Diuresis; Eclampsia; Female; Fever; Hemoglobinuria; Hemolysis; Humans; Jaundice; Kidney Cortex Necrosis; Kidney Diseases; Nephritis; Nephritis, Interstitial; Penicillins; Pregnancy; Sepsis; Tetracycline

Topics: Adolescent; Anti-Bacterial Agents; Antibody Formation; Drug Resistance; Drug Resistance, Microbial; Hemolysis; Humans; Kanamycin; Microbiology; Mycoplasma; Mycoplasma pneumoniae; Penicillins; Pneumonia; Pneumonia, Bacterial; Pneumonia, Viral; Sulfonamides; Tetracycline

Topics: Abortion, Criminal; Abortion, Septic; Acute Kidney Injury; Adrenal Cortex Hormones; Anti-Bacterial Agents; Bacillus; Chloramphenicol; Clostridium perfringens; Criminals; Female; Gas Gangrene; Hemoglobinuria; Hemolysis; Humans; Kidneys, Artificial; Oleandomycin; Pigmentation Disorders; Pregnancy; Renal Insufficiency; Sepsis; Tetracycline