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Biomedical subjects

I A Mikhail

Publications and source records attributed to I A Mikhail.

33 records · Page 2Linked to original sources

Rapid, economical diagnosis of enteric fever by a blood clot culture coagglutination procedure.

Coagglutination tests with Salmonella A, D, Vi, and polyvalent antiserum-sensitized staphylococcal cells were compared with conventional culture methods for detecting salmonellae in ox bile cultures of blood clots from enteric fever patients. The coagglutination tests appeared equally as effective as conventional subculture methods for detecting positive cultures (95% agreement). In addition, the coagglutination method yielded earlier results at reduced cost.

Bacteriological Techniques↗

Interaction of Salmonella paratyphi A and Schistosoma mansoni in hamsters.

It has previously been shown that Salmonella paratyphi A associates with adult Schistosoma mansoni worms in animal models and in patients with schistosomiasis, resulting in Salmonella infections that are difficult to manage unless the helminthic parasite is eliminated. In the present study, characteristics of this association were explored. In vitro, fresh serum, but not heat-inactivated (56 degree C, 30 minutes) serum, from normal hamsters (NH) and schistosome-infected hamsters (SIH) equally inhibited bacterial growth. When either group of animals was given S. paratyphi A intracardially, there was a decline in recoverable bacteria in the blood for 3 days, but after the third day, the number of bacteria increased in SIH whereas NH blood became sterile. Co-cultivation of S. paratyphi A in Earle's medium with live worms yielded more bacterial growth than occurred in the medium without worms, suggesting that nutritional factors are involved in the relationship. An intimate association in vivo of bacteria and trematodes was confirmed by culturing Salmonella from both worm surfaces and homogenized worms, with more bacteria being recovered from female worms. Although the bacterial infection induced a significant hepatic shift of adult worms in SIH, oogram analyses were normal and no lethal effect of bacteria on worms was noted.

Animals↗

Chronic Salmonella bacteriuria with intermittent bacteremia treated with low doses of amoxicillin or ampicillin.

Amoxicillin and ampicillin were compared at a dose of 250 mg twice daily for 4 weeks to treat Salmonella typhi or Salmonella paratyphi A chronic bacteriuria with intermittent bacteremia. Eleven patients received amoxicillin, and 15 received ampicillin. Concentrations of the two drugs were measured in the urine and serum on treatment days 1, 2, and 7. The urine levels of both antibiotics were maximal 2 h after administration, and minimal levels were 80-fold higher than the S. typhi minimal inhibitory concentration and 20-fold higher than the S. paratyphi A minimal inhibitory concentration. The serum level of amoxicillin was below the minimal inhibitory concentration of S. paratyphi A 6 h after administration on each of the testing days. The serum antibiotic levels of the two drugs showed no cumulative effect at day 2 or day 7. Of the 11 patients treated with amoxicillin, 1 had positive urine cultures during treatment, and 1 treated with ampicillin continued to be symptomatic.. Recurrence of bacteriuria occurred in three of seven patients with persistent bladder calcification. None of the 26 patients in this study had positive blood culture during or after treatment. Amoxicillin and ampicillin at a dose of 250 mg twice daily were equally successful in treating chronic salmonelluria.

Adolescent↗

Cerebrospinal fluid and serum ampicillin levels in bacterial meningitis patients after intravenous and intramuscular administration.

28 patients with bacterial meningitis received ampicillin by the intramuscular (IM) route and 16 patients by the intravenous (IV) route. The mean cerebrospinal fluid (CSF) ampicillin levels were similar in the two groups 1 h after a dose given on the first or second day of treatment, but they were higher in the IM group on both days 4 h after a dose. CSF/serum ratios were similar in both groups but considerably higher at 4 h than at 1 h.

Adolescent↗

Salmonella paratyphi A in hamsters concurrently infected with Schistosoma mansoni.

The present work deals with the development of an improved animal model to study the association of salmonellosis and schistosomiasis. The animal chosen was the hamster, Mesocricetus auratus, which can be readily infected with Schistosoma mansoni. Normal hamsters and schistosome-infected hamsters (SIH) were given approximately 2.0 x 10(7) Salmonella paratyphi A intracardially. It was found that S. mansoni infections enhanced and prolonged the growth of S. paratyphi A in hamsters. Animals with dual infections had increased mortality in comparison with those infected with just bacteria or parasite during the 50 days post-bacterial challenge. Further studies showed that in SIH, S. paratyphi A persisted in various organs for up to 8 weeks post infection. In contrast, concurrent Leishmania donovani infections have no effect on S. paratyphi A infections. Significant numbers of bacteria were cultured from well-washed schistosome worms recovered from SIH 6--8 weeks post-bacterial challenge. These findings suggest that a direct physical relationship between the bacteria and worms facilitates the establishment and growth of S. paratyphi A in vivo, and that a deficit in host immune response is not a major factor involved in the enhanced growth of S. paratyphi A.

Animals↗

Penetration of amoxicillin into cerebrospinal fluid.

The penetration of amoxicillin into cerebrospinal fluid (CFS) in the presence of meningeal inflammation was evaluated in patients with tuberculous meningitis. Serum and CSF concentrations of amoxicillin were measured at 2 h in nine patients who received a 1-g oral dose and at 1.5 and 4 h in ten patients who received a 2-g intravenous injection of sodium amoxicillin. After the oral dose, CSF concentrations ranged from 0.1 to 1.5 mug/ml. After the intravenous injection, CSF concentrations ranged from 2.9 to 40.0 mug/ml at 1.5 h and from 2.6 to 27.0 mug/ml at 4 h. These data on penetration suggest that parenterally administered sodium amoxicillin may be of value in the therapy of acute bacterial meningitis.

Adolescent↗

Treatment of chronic enteric fever with amoxicillin.

Twelve patients with proven Salmonella typhi or Salmonella paratyphi A bacteriuria and recurrent bacteremia associated with schistosomiasis were treated for four weeks with amoxicillin (250 mg four times daily). Seven of the 12 patients were seriously ill and febrile before treatment. They showed a dramatic response, and, within three to six days of initiation of amoxicillin therapy, they were afebrile and much improved clinically. Amoxicillin was rapidly and highly concentrated in the urine of all patients; peak levels of 115-2,700 mug/ml were obtained within 2-4 hr of the first dose. Concentration of the drug in serum was also rapid and in all but two patients exceeded the minimal inhibitory concentration of the organism within 4 hr of the first dose. Within one week after treatment started, all urine and blood specimens obtained from the patients became negative for Salmonella and remained so throughout the four-week follow-up period, during which the patients were hospitalized.

Administration, Oral↗

Controlled field trial of a typhoid vaccine prepared with a nonmotile mutant of Salmonella typhi Ty2.

A controlled field trial was performed in Egypt to evaluate a whole cell typhoid vaccine prepared with a nonmotile mutant of S. typhi Ty2 (TNM1) devoid of flagellar antigen. This vaccine did not elicit an H antibody response, but significant Vi and O agglutinin responses were observed. There were 34 typhoid cases among 21 063 six- to seven-year-old children who received the TNM1 vaccine, and 44 cases among 21 017 children in the control group who received tetanus toxoid. These results suggest that TNM1 vaccine does not provide protection against typhoid fever, and that H antigen may be an important component of an effective vaccine.

Child↗

Concentrations of ampicillin and chloramphenicol in the serum of patients with acute Salmonella enteric fever.

Concentrations of ampicillin and chloramphenicol were measured in the serum of patients being treated for acute infections by Salmonella typhi or S. paratyphi A. Ampicillin was administered by the oral or intramuscular routes, whereas chloramphenicol was given orally only. Ampicillin concentrations were highest 1 hr after initiation of intramuscular therapy and 2 hr after oral administration. The serum concentration of ampicillin was significantly higher when it was given intramuscularly than when it was given orally. However, serum concentrations in orally treated patients were approximately the same at 1 hr after the fifth dose as they were 1 hr after the first dose, in contrast to intramuscularly treated patients, in whom the serum concentration of ampicillin was significantly lower 1 hr after the fifth dose. On the other hand, serum concentrations of chloramphenicol were significantly higher after the fifth dose than after the first dose. The rates of cure, relapse, and drug treatment failure were similar for all treatment regimens, and the drug concentrations attained in serum were generally above the minimal inhibitory concentration for the infecting salmonellae.

Adolescent↗