Effect of ciprofloxacin antibiotic on the partial-nitritation process and bacterial community structure of a submerged biofilter.

A partial-nitritation bench-scale submerged biofilter was used for the treatment of synthetic wastewater containing a high concentration of ammonium in order to study the influence of the antibiotic ciprofloxacin on the partial-nitritation process and biodiversity of the bacterial community structure. The influence of ciprofloxacin was evaluated in four partial-nitritation bioreactors working in parallel, which received sterile synthetic wastewater amended with 350 ng/L of ciprofloxacin (Experiment 1), synthetic wastewater without ciprofloxacin (Experiment 2), synthetic wastewater amended with 100 ng/L of ciprofloxacin (Experiment 3) and synthetic wastewater amended with 350 ng/L of ciprofloxacin (Experiment 4). The concentration of 100 ng/L of antibiotics demonstrated that the partial-nitritation process, microbial biomass and bacterial structure generated by tag-pyrosequencing adapted progressively to the conditions in the bioreactor. However, high concentrations of ciprofloxacin (350 ng/L) induced a decay of the partial-nitritation process, while the total microbial biomass was increased. Within the same experiment, the bacterial community experienced sequential shifts with a clear reduction of the ammonium oxidation bacteria (AOB) and an evident increase of Commamonas sp., which have been previously reported to be ciprofloxacin-resistant. Our study suggests the need for careful monitoring of the concentration of antibiotics such as ciprofloxacin in partial-nitritation bioreactors, in order to choose and maintain the most appropriate conditions for the proper operation of the system.

Extracorporeal renal lithotripsy: evolution of residual lithiasis treated with thiazides.

OBJECTIVES: To analyze the evolution of residual lithiasis after renal extracorporeal shock wave lithotripsy (ESWL) and to show the prolonged efficacy of thiazides in the treatment of residual lithiasis in patients with calcium lithiasis. METHODS: We performed a longitudinal, analytical, 36-month study in 100 patients with residual calcium lithiasis after ESWL randomly distributed into two groups: 50 patients treated with placebo (controls, group 1) and 50 treated with hydrochlorothiazide, 50 mg/24 hr (group 2). All patients in both groups underwent imaging studies (simple radiography of the urinary tract and renal ultrasonography) and a metabolic urinary study. RESULTS: The percentage of global expulsion of lithiasis during the follow-up period was significantly greater (chi-square exponent = 19.938, P = 0.001) in the patients treated with thiazides (72%) than in the control group (36%), although a large number of patients in this group underwent new ESWL sessions. During the follow-up period, we performed ESWL on 42% of the patients in group 1 and 18% of group 2, a statistically significant difference (chi-square exponent = 6.881, P = 0.032). CONCLUSIONS: The results of our study have shown that residual lithiasis progresses in 58% of patients undergoing observation, and new ESWL sessions will be necessary in 42%. We observed a significant relationship between the presence of a urinary lithogenic pattern and the progression of the residual lithiasis. The administration of thiazides stabilizes or reduces the growth of residual lithiasis and favors its spontaneous elimination, thus reducing the need for new sessions of ESWL. This effect of thiazides is highly significant in patients presenting with hypercalciuria.

[Effect of thiazide therapy in the prophylaxis of calcium lithiasis]. / Efecto de las tiazidas en la profilaxis de la litiasis cálcica.

OBJECTIVE: To analyze the role of thiazide therapy in the prevention of recurrent calcium nephrolithiasis, considering the hypocalciuric action of this drug. METHODS: A prospective study before and after treatment, with a 3-year follow-up, was carried out on 150 patients with recurrent calcium renal stone. The patients were divided into three groups: (A) no treatment, (B) treatment with thiazide 50 mg/day and (C) treatment with thiazide and potassium citrate. The treated groups were randomly assigned to the treatment arms. Control analytical tests and radiological assessments were performed regularly. RESULTS: Excellent results were achieved with thiazide therapy in regard to stone recurrence and changes in residual stone in comparison to the group of untreated patients (group A). The most common metabolic disorder was absorptive hypercalciuria type I. Most of the patients showed a single metabolic disorder. The side effects were generally not relevant. CONCLUSIONS: Thiazides should be considered as the first line of treatment in absorptive and excretory hypercalciuria. We believe that in unselected patients with calcium stone, thiazide therapy can be effective in its prevention. It is important to take into account the possible side effects of the drug and supplementation with potassium citrate for thiazide-induced hypocitraturia.