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Biomedical subjects

J Segreti

Publications and source records attributed to J Segreti.

44 records · Page 3Linked to original sources

Results of a screening method used in a 12-month stool survey for Escherichia coli O157:H7.

Escherichia coli serotype O157:H7 has been epidemiologically linked to outbreaks of hemorrhagic colitis associated with fast-food restaurants and nursing homes. Sporadic cases now exceed those associated with outbreaks. The incidence of the organism in patients with common diarrhea syndromes and in asymptomatic persons is unknown. Routine serotyping of E. coli isolates is impractical for most clinical microbiology laboratories. We developed a screening plate by utilizing sorbitol fermentation as a biochemical marker to identify organisms for serotyping. A total of 2,552 stool samples were screened. In 106 (4.1%), sorbitol-negative E. coli were identified. Of these, two were serotype O157:H7, and both produced a Vero cell toxin. One patient had hemorrhagic colitis and the other a mild, febrile, self-limited diarrhea with no other bacterial pathogen identified. This plate provides an easy, effective method of screening for sorbitol-negative E. coli, a process facilitating the selection of organisms for serotyping and one that may help clarify this organism's role in human disease.

Canada↗

In vitro activity of minocycline and rifampin against staphylococci.

We tested the in vitro inhibitory and bactericidal activity of minocycline against 26 methicillin-susceptible Staphylococcus aureus, 24 methicillin-resistant S. aureus, 1 methicillin-susceptible coagulase-negative staphylococci, and 33 methicillin-resistant coagulase-negative staphylococci. Minocycline and rifampin had MIC90 results in the susceptible range, but MBCs were markedly elevated for minocycline alone (MBC50 greater than 32 micrograms/ml). The combination of minocycline and rifampin was synergistic for 30% of the isolates with the highest rates of synergy being against methicillin-resistant isolates.

Drug Synergism↗

In vitro activity of tosufloxacin against bacterial enteric pathogens.

The in vitro activity of tosufloxacin (A-61827), a new quinolone antibiotic, was compared with that of four other quinolones against 162 bacterial enteric pathogens. Susceptibility testing was performed by using an agar dilution method. The minimal inhibitory concentration (MIC) was defined as the lowest concentration of antibiotic without visible growth. Tosufloxacin was the most active agent against Campylobacter jejuni and C. coli, and ciprofloxacin was the most active agent against Salmonella, Shigella, and Vibrio. The frequency of spontaneous point mutational resistance to tosufloxacin for three C. jejuni ranged from 1.2 x 10(-9) to 5.1 x 10(-13). No significant differences in mutational frequency were seen among the quinolones.

Anti-Infective Agents↗

In vitro activity of beta-lactam drugs and sulbactam against Chlamydia trachomatis.

We tested the in vitro activity of ampicillin, ampicillin-sulbactam, cefoperazone, cefoperazone-sulbactam, and sulbactam against 18 recent clinical isolates of Chlamydia trachomatis and two ATCC strains. Ampicillin (MIC50, 256 micrograms/ml) and sulbactam (MIC50, 128 micrograms/ml) demonstrated some activity against C. trachomatis, but cefoperazone had little to no activity. At 2-3 dilutions below the MIC, C. trachomatis treated with ampicillin or sulbactam, but not cefoperazone, formed small inclusions that remained small on passage onto antibiotic-free McCoy cells. It appears that ampicillin and sulbactam suppress rather than kill C. trachomatis.

Ampicillin↗

In vitro activity of new quinoxaline compounds against Campylobacter species and Clostridium difficile.

SC-44914 and SC-44942-A are two new quinoxaline compounds with a spectrum of activity similar to that of metronidazole. We studied the activity of SC-44914 and SC-44942-A against 35 Campylobacter jejuni, 30 C. coli, and 20 Clostridium (Cl.) difficile and compared it with that of metronidazole by utilizing an agar dilution method. The quinoxalines had little activity against the C. jejuni and C. coli [minimum inhibitory concentration (MIC)90 > or = 64 micrograms/ml]. SC-44914 and SC-44942-A had excellent activity against Cl. difficile (MIC90 < or = 0.06 micrograms/ml for SC 44914, and 0.5 micrograms/ml for SC-44942A).

Anti-Bacterial Agents↗