Periodontitis is an inflammatory disease of the supporting structures of the teeth and is caused by, among other agents, Porphyromonas gingivalis. P. gingivalis is very resistant to killing by human complement, which is present in a gingival fluid at 70% of the serum concentration. We found that the incubation of human serum with purified cysteine proteases of P. gingivalis (gingipains) or P. g...

The effects of nalidixic acid and four fluoroquinolones on DNA, RNA, and protein synthesis in the presence and absence of 20 mg of chloramphenicol per liter were examined by comparing the killing kinetics, MIC, morphological response, and maximum concentration to induce recA in Escherichia coli. All agents demonstrated paradoxical killing kinetics, in that above an optimum concentration the rat...

We are indeed encouraged to learn of the successful use of trimethoprim and sulfamethoxazole in combination with other antimicrobial agents for treating disseminated melioidosis, as reported by Tanphaichitra and coauthors In our single experience with life-threatening disease limited to the lungs (Chest 74:222-224, 1978), antagonism occurred when trixnethoprim and sulfamethoxazole were used in ...

Antimicrobial agents are most often tested against bacteria in the log phase of multiplication to produce the maximum bactericidal effect. In an infection, bacteria may multiply less optimally. We examined the effects of several classes of antimicrobial agents to determine their actions on gram-positive and gram-negative bacteria during nongrowing and slowly growing phases. Only ciprofloxacin a...

The successful photochemical splitting of water with a TiO2 electrode has established that TiO2 has to be considered as one of the most important semiconductor photocatalysts. This photocatalyst has been shown to be efficient to mineralize several organic compounds and thereby remove a variety of pollutants and wastes. For safe drinking water, the present environmental conditions demand new tec...

Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the ...

We used classical mutagens in Gram-negative Escherichia coli to study synergies with different classes of antibiotics, test models of antibiotic mechanisms of action, and examine the basis of synergy. We used 4-nitroquinoline 1-oxide (4NQO), zebularine (ZEB), 5-azacytidine (5AZ), 2-aminopurine (2AP), and 5-bromodeoxyuridine (5BrdU) as mutagens (with bactericidal potency of 4NQO > ZEB > 5AZ > 2A...

Enterococcus faecalis (E. faecalis) has become a major leading cause of nosocomial endocarditis. Treatment of such infections remains problematic and new therapeutic options are needed. Nine E. faecalis strains were tested: six obtained from patients presenting endocarditis, one with isolated bacteremia, and two reference strains. Antibiotics included daptomycin, alone or in combination, linezo...

While granulocyte transfusions have been shown to be effective in the treatment of patients with infections, the effects of the leukapheresis collection procedure on certam granulocyte functions remain in question. We studied the bactericidal function of granulocytes collected by continuousflow centrifugation (CFC) and filtration Ieukapheresis (FL) with S. aureus, E. coil, and S. typhimurium. K...

Questionnaires were sent to 37 diagnostic microbiology laboratories to assess their methods for performance of the serum bactericidal test. Of the 28 responding laboratories, 26 utilized the test, with considerable variation among methods. Culture and dilution media included Trypticase soy, Mueller-Hinton, brain heart infusion, Columbia broth, dextrose phosphate, and pooled human serum. Several...