The effect of sulfamonomethoxine treatment on the gut microbiota of Nile tilapia (Oreochromis niloticus).

To investigate the possible effects of sulfamonomethoxine (SMM) on Nile tilapia (Oreochromis niloticus), we quantitatively evaluated the microbial shifts in the intestines of Nile tilapia in response to different doses of SMM (200 and 300 mg/kg) using 16S rRNA gene sequencing. At the phylum level, the control group (0 mg kg-1  SMM) was dominated by Actinobacteria, Proteobacteria, and Firmicutes. In the treatment groups, Firmicutes, Proteobacteria, and Chloroflexi were the dominant phyla. Cluster analysis indicated that the two groups treated with SMM clustered together. Similarly, the bacterial families that dominated the control group differed from those dominating the treatment groups. The changes in intestinal microbial composition over time were similar between the two SMM treatment groups. In both groups, the abundances of some families, including the Bacillaceae, Streptococcaceae, and Pseudomonadaceae, increased first and then decreased. Overall, the addition of SMM to the feed changed the structure of the intestinal microbiota in Nile tilapia. This study improves our understanding of the impact of SMM on the intestinal microenvironment of Nile tilapia. Our results provide guidelines for the feasibility of SMM use in aquaculture production.

A compositional shift in the soil microbiome induced by tetracycline, sulfamonomethoxine and ciprofloxacin entering a plant-soil system.

Antibiotics entering the soil likely disturb the complex regulatory network of the soil microbiome, which is closely associated with soil quality and ecological function. This study investigated the effects of tetracycline (TC), sulfamonomethoxine (SMM), ciprofloxacin (CIP) and their combination (AM) on the bacterial community in a soil-microbe-plant system and identified the main bacterial responders. Antibiotic effects on the soil microbiome depended on antibiotic type and exposure time. TC resulted in an acute but more rapidly declining effect on soil microbiome while CIP and SMM led to a delayed antibiotic effect. The soil exposed to AM presented a highly similar bacterial structure to that exposed to TC rather than to SMM and CIP. TC, SMM and CIP had their own predominantly impacted taxonomic groups that include both resistance and sensitive bacteria. The antibiotic sensitive responders predominantly distributed within the phylum Proteobacteria. The potential bacteria resistant to each antibiotic exhibited phyla preference to some extent, particularly those resistant to TC. CIP and SMM resistance in soil was increased with exposure time while TC resistance gave the opposite result. Overall, the work extended the understanding of antibiotic effects on soil microbiome after introduced into the soil during greenhouse vegetable cultivation.

Mutagenicity screening of feed additives in the microbial system.

18 feed additives were tested for DNA-modifying effects by the repair test named "rec-assay" with Bacillus subtillis H17 (rec+) and M45 (rec-), and for mutagenicity with Escherichia coli WP2 hcr and 5 Salmonella typhimurium tester strains with the use of a top-agar overlay method. Carbadox, furazolidone, panazon and zoalene were positive in both assays. The former 3 were mutagenic for TA100, TA98 and WP2 hcr, while zoalene was mutagenic for all strains. These 4 compounds did not require a metabolic activation for their mutagenic activities. Nicarbazin was weakly mutagenic for TA1538 and TA98 with and without S9 mix. Amprolium and caprylohydroxamic acid also showed very weak mutagenicities only for TA100 with S9 mix and for WP2 hcr with and without S9 mix, resp. The mutagenic activities of carbadox, furazolidone and panazon for TA100 were reduced only by the addition of S9 mix, but not by S9 fraction or blood, whereas that of zoalene was decreased by any of the 3 factors.

Comparison of the inhibitory effect of sulfamonomethoxine and other sulfonamides on capsule formation of Bordetella bronchiseptica.

The inhibitory effect of sulfamonomethoxine and other sulfonamides on the capsule formation of sulfonamide-resistant Bordetella bronchiseptica was investigated. All the sulfonamides having MeO(-OCH3) groups inhibited the capsule formation of B. bronchiseptica. Strong inhibition was obtained with sulfamonomethoxine. Inhibition was not seen with sulfonamides having no MeO groups.

[Determining the sensitivity of Pseudomonas to chemotherapeutic preparations by the micromethod in liquid synthetic medium]. / Opredelenie chuvstvite'lnosti pseudomonad k khimioterapevti- cheskim preparatam mikrometodom v zhidkoi sinteticheskoi srede.

Ever increasing interest is being displayed lately to simple, economic and standard systems for assay of antibiotic sensitivity of microbes with microtechniques in nutrient media requiring no raw materials in short supply. For determining sensitivity of Pseudomonas spp. to chemotherapeutics a liquid synthetic medium balanced by its cationic composition and containing no competing agents of sulfanylamides was used. Three procedures were comparatively estimated: the method of serial dilutions in the liquid medium with using immunological trays, the method of serial dilutions in agar and the diffusion test. In the estimation 185 strains of various Pseudomonas species were used: P. aeruginosa, P. cepacia, P. fluorescens, P. stutzeri, P. putida and P. pseudomallei. The method using the liquid synthetic medium and trays provided more precise interpretation of the results of the assay of the Pseudomonas spp. sensitivity to aminoglycosides, tetracycline, polymyxin and sulfamonomethoxine that the routine procedures. It showed some other advantages such as simplicity, low cost, low medium requirement and glassware economy. The application of the method allowed to exclude the use of expensive imported nutrient media in assay of sulfanylamide sensitivity.

Soil microbial systems respond differentially to tetracycline, sulfamonomethoxine, and ciprofloxacin entering soil under pot experimental conditions alone and in combination.

This study investigated soil microbial responses to the application of tetracycline (TC), sulfamonomethoxine (SMM), and ciprofloxacin (CIP) alone and in combination in a soil culture pot experiment conducted at Hangzhou, China. Multiple approaches were applied for a better and complete depiction. Among the three antibiotics, SMM has a lowest dissipation and shows a most dramatic inhibition on microbial community and metabolism diversity. The combined application (AM) of SMM, CIP, and TC improved the dissipation of each antibiotic; similarly, SMM- and CIP-resistant bacteria showed larger populations in the AM than all single applications. Soils accumulated a large content of NO3-N at day 20 after multi-antibiotics perturbation. All antibiotics stimulated soil basal respirations and inhibited soil metabolism diversity, whereas the interruption exerted by SMM and AM lasted for a longer time. Six nitrogen-cycling genes including chiA, amoA, nifH, nirK, nirS, and narG were quantified and found to decrease owing to both single- and multi-antibiotics perturbation. Overall, AM was most interruptive for soils, followed by SMM perturbation, while other antibiotics could be less interruptive. These results provide systematic insights into how soil microbial systems would shift under each single- or multi-antibiotics perturbation.

Inhibitory effect of sulfamonomethoxine on capsule formation of Bordetella bronchiseptica.

Bordetella bronchiseptica phase I organism possesses a capsule and has the ability to agglutinate with K antiserum, although phase III organism lacks both. The present study examines the effect of sulfamonomethoxine (SMMX) on capsule formation of B. bronchiseptica. I also investigated whether or not the organisms possessed a capsule by bacterial agglutination with K antiserum. Three SMMX-resistant strains of B. bronchiseptica phase I organisms showed loss of agglutinability with K antiserum by culturing them at a higher concentration of 1.56 micrograms/ml of SMMX. These results indicated that capsule formation of SMMX-resistant B. bronchiseptica is inhibited by SMMX.

Chemotherapy of falciparum malaria: regional differences in responsiveness to treatment.

A review of chloroquine and sulfa-antifol combination treated falciparum malaria patients revealed a high incidence of chloroquine-resistance, wither R1 or R2, in patients infected in Southeast Asia or Oceania. In addition, more than one tenth of the patients infected in Laos or Thailand were resistant to sulfa-antifol combinations. Chloroquine-resistant cases were sensitive to sulfa-antifol combinations. On the other hand, while all patients treated in Tokyo who had been infected in Africa or Sri Lanka were sensitive to chloroquine, a field study suggested the presence of chloroquine-resistant P. falciparum in the area near Kaduna, Nigeria. One patient infected in Nigeria showed partial resistance to the MP (sulfamonomethoxine-pyrimethamine) combination, and another patient infected in the Central African Empire showed resistance to the MP combination, increasing from R1 to R3 within a short period. The incidence of resistance to sulfa-antifol combination therapy was high in the West African tropical region. The continent, county and area of infection should be taken in consideration when selecting antimalarial drug(s) for the treatment and suppression of falciparum malaria.

Antithyroid effects of propylthiouracil and sulfamonomethoxine in rats and monkeys.

Experiments were performed to investigate the species difference in antithyroid effects of propylthiouracil (PTU) and sulfamonomethoxine (SMM). Sprague-Dawley rats were administered 30 mg/kg of PTU, or 30 or 270 mg/kg of SMM orally for 5 weeks, while squirrel monkeys received 30 mg/kg of PTU or 270 mg/kg of SMM. In rats receiving 30 mg/kg of PTU, a decrease of both serum 3,5,3'-triiodothyronine and thyroxine concentrations and of 131I incorporation into the thyroid hormone precursors was observed, together with elevation of serum thyroid-stimulating hormone concentration, an increase in thyroid weight, and hyperplasia of the follicular epithelium of the thyroid gland. Similar changes were seen in rats receiving 270 mg/kg of SMM; however, the antithyroid effects of SMM were less severe than those of PTU. No change was produced in monkey thyroids by 5-week treatments with 30 mg/kg of PTU or with 270 mg/kg of SMM. The molar concentration of PTU required for the in vitro inhibition of thyroid peroxidase was markedly lower in rats than in monkeys. SMM showed a similar species difference in the inhibition of thyroid peroxidase in vitro, but the enzyme inhibition of SMM was weaker than that of PTU. These findings suggest that rats were more sensitive to the antithyroid effects of PTU and SMM than monkeys, and that inhibition of thyroid peroxidase may play an important role in species difference in the antithyroid effects of the two drugs.

Reinfecçäo pelo Toxoplasma gondii Nicole & Manceaux, 1909 em camundongos e gatos: estudo experimental / Reinfection by Toxoplasma gondii Nicolle & Manceaux, 1909 in mice and cats: experimental study

A refeiçäo pelo Toxoplasma gondii foi estudada, experimentalmente, em 27 camundongos albinos e 25 gatos domésticos. A infecçäo e a reinfecçäo foram comprovadas por sinais clínicos, anticorpos sangüíneos à reaçäo de Sabin & Feldman >- 1/4, recuperaçäo do parasita e, nos gatos, também pela eliminaçäo de oocistos. Nos camundongos a mortalidade foi de 56%. A primo-infecçäo por cepa de baixa virulência ou a infecçäo por cepa mais virulenta, atenuada pela sulfamonometoxina, deram proteçäo à reinfecçäo por cepa mais virulenta, mortal em poucos dias. Esta proteçäo foi demonstrada pela sobrevivência de camundongos e menor mortalidade, 12,5%. Nos gatos a mortalidade foi de 28%. A resposta sorológica à primo-infecçäo ocorreu em todos. Após a reinfecçäo houve elevaçäo de títulos em 64% dos gatos, permanência em 32% e queda em 4%. A eliminaçäo de oocistos foi observada em 60% dos gatos e só após inoculaçäo de cistos, por via digestiva. A reeliminaçäo após reinfecçäo, ocorreu em 25% dos gatos. Näo foi observada eliminaçäo após a 3ª inoculaçäo. Em 88,2% dos gatos houve recuperaçäo do parasita em camundongo, mais freqüente nos linfonodos mesentéricos e no intestino delgado, persistindo neste cerca de 14 meses. Foi constatada certa relaçäo entre o bom estado físico dos gatos e a resposta sorológica, a eliminaçäo e a reeliminaçäo de oocistos. Apesar da persistência de anticorpos sangüíneos a reinfecçäo experimental dos gatos foi observada, porém a reeliminaçäo de oocistos foi pouco freqüente e em pequena quantidade