Antitrichomonal Agents 5-Nitrothiazoles, 5-Nitropyridines and 5-Nitropyrimidines

Some 5-nitrothiazoles, 5-nitropyridines and 5-nitropyrimidines have been synthesised and evaluated against Trichomonas vaginalis and Trichomonas foetus in vitro and in vivo in the mouse, hamster and monkey. Although 2-amino-5-nitropyrimidine, 2-acetamido-5-nitropyrimidine and 2-trifluoroacetamido-5-nitropyrimidine were highly active in mice infected with T. vaginalis the activity was not superior to the standard 2-acetamido-5-nitrothiazole. The nitropyrimidines were highly species specific, being much more active in vivo against T. vaginalis than against T. foetus. One compound, 2-amino-5-nitropyrimidine was selected as the best of this series because of the high blood levels obtained after a single oral dose in a monkey, and its presence in a biologically active form

Antitrichomonal Agents Triazen Derivatives

Six new triazens have been synthesised. One of these compounds, 3-(2′-diethylaminoethyl)-3-ethyl-1-(p-nitrophenyl)-triazen was active in mice against Trichomonas vaginalis but inactive against Trichomonas foetus

Double infection with Giardia lamblia and Salmonella paratyphi A associated with acute renal failure

While traveling in India, a previously healthy twenty-year-old man had febrile diarrhea. The patient was prescribed medical therapy, and all symptoms were resolved. Fourteen days later, however, similar symptoms recurred. The patient was admitted to a local hospital, but was transferred to our department because of oliguria. Salmonella paratyphi A was isolated from blood and stool specimens, and Giardia lamblia was identified in his stool. The patient's condition was complicated by acute renal failure. The patient received tosufloxacin and metronidazole. Renal function recovered completely without hemodialysis. Paratyphoid fever and giardiasis were resolved. It is suggested that giardiasis exacerbated the paratyphoid fever.

Secondary impairment of pancreatic function as a cause of severe malabsorption in intestinal giardiasis: a case report

We report the case of a 54-year-old male patient hospitalized for diarrhea and weight loss (8 kg over the previous three months). At admission, we observed pale oral and conjunctival mucosa and peripheral edema of the lower limbs. Stool frequency was 8-10 per day. Laboratory data were as follows: hemoglobin, 11 g/dL; total proteins, 4.3 g/dL; albumin, 2 g/dL; pseudocholinesterase, 1248 U/L; triglycerides, 54 mg/dL; serum cholesterol, 102 mg/dL; calcium, 7.9 mg/dL. Fecal fat was 8.2 g/24 hr. Fecal chymotrypsin (FCT) was 2.3 U/g. A duodenal probe was performed after administration of intravenous secretin and cerulein stimulation, and a contemporaneous mucosal biopsy was taken at the ligament of Treitz. Microscopic examination showed numerous Giardia lamblia in the fluid collected. Pancreatic enzyme activity in the duodenal fluid showed a severe reduction in lipase: 120 U/ml/min (normal value = 600 U/ml/min). Small bowel bacterial overgrowth was excluded by microbiologic examination of intestinal fluid. The patient was treated with metronidazole, leading to a complete remission of symptoms. Immediately after stopping treatment, the FCT was 15.2 U/g. Four months after hospitalization, the patient's weight had increased by 11 kg and he was asymptomatic; total proteins were 6.7 g/dL; albumin, 3.8 g/dL; triglycerides, 104 mg/dL; cholesterol, 152 mg/dL; pseudocholinesterase, 3,567 mg/dL; calcium, 10 mg/dL; steatorrhea was 3.6 g/24 hr and fecal chymotrypsin was 88 U/g. This case describes a severe, reversible impairment in pancreatic function leading to clinical malabsorption in the presence of Giardia infection.

Efficacy of a combined diloxanide furoate-metronidazole preparation in the treatment of amoebiasis and giardiasis

A combined formulation of diloxanide furoate and metronidazole was used to treat amoebiasis and giardiasis (cysts and vegetative forms) in 54 patients. Of these 34 patients had amoebiasis, 19 had giardiasis and one had mixed infection. Each patient took one tablet (containing 500 mg diloxanide furoate and 400 mg metronidazole), three times daily for 5 days, and the response to therapy was checked by clinical examination and by examination of fresh stools on days 3, 5 and 10. Abdominal pain was completely relieved in 91% and 84% of patients with amoebiasis and giardiasis, respectively, while parasitic clearance was 100% in both groups. Tolerance to the drug was adequate.

Determination of metronidazole in vaginal tissue by high-performance liquid chromatography using solid-phase extraction

A sensitive high-performance liquid chromatographic (HPLC) method for the determination of metronidazole in vaginal tissue is reported. The method uses a Zorbax SB phenyl column with a 0.01 M aqueous monobasic potassium phosphate buffer (pH 4.0)-absolute methanol (85:15, v/v) as mobile phase at a flow-rate of 1.0 ml/min and detection at 313 nm. Tinidazole was used as the internal standard. The method employed homogenization of tissue followed by solid-phase extraction. The quantitation was achieved within 30 min with sensitivity in the ng/g range. Metronidazole was linear in the 100-2000 ng/g range. The accuracy and precision were in the 1-4% range for the drug and the limit of detection was approximately 100 ng/g based on a signal-to-noise ratio of 3 and a 1009-microliters injection.

In vitro activity of tetracyclines, macrolides, quinolones, clindamycin and metronidazole against periodontopathic bacteria

We re-evaluated several antibiotics including newer ones, for their in vitro killing activity, as well as their inhibitory activity, against clinical isolates of periodontopathic bacteria. Tetracyclines were active against Porphyromonas gingivalis, and were highly active against Prevotella intermedia, but demonstrated only a low killing activity against Actinobacillus actinomycetemcomitans. Rokitamycin, a new macrolide, and clindamycin were highly active against P. gingivalis and P. intermedia, but showed very weak killing activity against A. actinomycetemcomitans. Quinolones demonstrated excellent bactericidal activity against A. actinomycetemcomitans, and good inhibitory and bactericidal activity against P. gingivalis and P. intermedia. Metronidazole had an activity almost equivalent to quinolones against P. gingivalis and P. intermedia; but it was the least active against A. actinomycetemcomitans.

Mechanism of toxicity of nitro compounds used in the chemotherapy of trichomoniasis

The mechanism of the trichomonicidal activity of metronidazole and other 5-nitroimidazoles appears to depend on the ferredoxin-mediated reduction of their nitro group, with generation of a reactive metabolite or metabolites which interact with DNA leading to a subsequent inhibition of nucleic acid and protein synthesis. Redox cycling of these compounds under aerobic conditions appears to be a detoxification reaction by inhibiting net reduction of the drugs, thereby inhibiting their uptake. On the other hand, redox cycling of nitrofurans or other compounds with more positive reduction potential results in formation of high steady-state concentrations of oxygen-derived metabolites that might be of toxicological significance. It seems likely that reduced metabolites of nitroimidazoles (perhaps through covalent binding to tissue macromolecules and/or thiols depletion) are also involved in the nitroimidazoles' toxic effects to animal tissues and in their mutagenic and carcinogenic action.

Comparative studies on the trichomonacidal activity of 5-nitroimidazole-derivatives in mice infected s.c. or intravaginally with T. vaginalis

The trichomonacidal efficacy of metronidazole, tinidazole, nimorazole and ornidazole was studied in mice infected s.c., or for comparison purposes intravaginally. In both test systems, the drugs revealed nearly the same order of efficacy, whereby the compounds showed a marked decrease of activity when analyzed in s.c. infected mice.