Action of Colloidal Bismuth Hydroxide Gel and its Commercial Cream on Enteropathogens and Colonizers of the Gastrointestinal Tract.

BACKGROUND: Acute diarrheal diseases constitute a world public health problem because they are the second cause of death in children under 5 years of age. Colloidal bismuth hydroxide gel (CBHG) is an active ingredient in low-cost, antidiarrhetic drugs for oral use; it does not inhibit intestinal motility, and it features very low intestinal absorption of <1%. MATERIALS AND METHODS: We analyzed the sensitivity by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC); the effect on bacterial growth by studying the specific growth velocity and the generation time in growth curves; and bacterial attachment by counting viable plaques, of enteropathogenic Escherichia coli, shigatoxigenic E. coli O157:H7, Klebsiella pneumoniae, Salmonella spp., and Shigella flexneri in the commercial cream (Chobet® bismuth cream with pectin [CBCHP]), its active ingredient (CBHG), and its excipients (E) separately. RESULTS: CBCHP: MIC 6-10 mg/ml and MBC 7.5-15 mg/ml of bismuth; CBHG: MIC 6-10 mg/ml of bismuth. E: No inhibition was observed at the concentration studied in this study. At very low subinhibitory concentrations of CBCHP and CBHG, there was already evidence of a significant decrease in growth, which could not be recorded for E. CBCHP and CBHG presented an elevated capacity for bacterial displacement, significantly greater than E. CONCLUSIONS: We believed that the results obtained in this study are very promising from the treatment standpoint, as a possible treatment for cases of diagnosis or suspicion of bacterial gastroenteritis. The antimicrobial and attachment effects of CBCHP are exclusively due to its active ingredient CBHG; these effects are promoted in the presence of E.

Clofibric and ethacrynic acids prevent experimental pyelonephritis by Escherichia coli in mice.

Interfering Escherichia coli attachment to the urinary tract, using P-fimbriation inhibitors, can prevent pyelonephritis. Clofibric and ethacrynic acids are organic compounds structurally related, but with different pharmacological uses. These agents are potentially active in the urinary tract due to its elimination in an unaltered form by the renal route. This study described a pyelonephritogenic E. coli strain, grown in the presence of sub-inhibitory concentrations of clofibric or ethacrynic acids (0.1 and 1 mM, respectively), which exhibits inhibition of P1 erythrocytes agglutination and a drastic decrease in fimbriation, using electron microscopy and quantitative analyses of superficial proteins (decrease to a 17-25% in comparison with the control). In vivo assays were performed using ascending urinary tract infection in mice. The treatment with therapeutic doses of the drugs, administered 2 days before the bacterial challenge and daily until the end of the experiment (22 days), abolished renal infection after 7-10 days of drug exposure. Within this period clofibric acid did not produce adverse effects on the renal parenchyma. However, ethacrynic acid caused pyelitis and tubular cellular desquamation. These results suggested that clofibric acid might be useful in the short-term prophylaxis of urinary tract infection.

Effect of the herbicide 2,4-dichlorophenoxyacetic acid on uropathogenic Escherichia coli virulence factors.

The effects of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D)-widely used in the world and mainly excreted by the renal route in exposed humans-were studied on the virulence and surface characteristics of an uropathogenic Escherichia coli strain. When the urine was supplemented with 2,4-D in vitro, the compound significantly reduced the bacterial fimbriation assayed by hemagglutination and surface protein quantification. Protein values decreased from 0.24 mg/g dw to 0.05 or 0.12 mg/g dw by 1 or 0.1 mM 2,4-D treatment, respectively. The effects in vivo were studied in groups of mice challenged intra-urethra with E. coli and exposed by the oral route with three different 2,4-D doses (2.6, 25 or 70 mg/kg bw) during 22 days. Depending on the dose used, the herbicide significantly decreased or removed bacterial cells in mice bladder and kidneys; except in the group treated with the highest dose from the 9th day of treatment. The histological studies showed mononuclear cell infiltration at low doses, and toxic damage in the renal parenchyma at prolonged exposure with higher doses, up to tisular necrosis in the 70 mg/kg bw group after 9 days of treatment. Our investigations performed in an experimental model suggest that short time 2,4-D exposure at low doses could act in prevention of UTI stimulating leukocytic migration and decreasing bacterial fimbriation. On the contrary, high doses and long-term exposure enhanced renal damage resulting in infection recurrence.

Efecto modulador de antibióticos sobre la adherencia bacteriana a biomateriales / Antibiotics modulation of bacterial adherence to medical biomaterials

La colonización de polímeros origina un foco de infección de difícil erradicación, debido a que las bacterias adheridas a materiales inertes presentaban propiedades fisiológicas especiales. Las infecciones urinarias complicadas debidas a sondas vesicales son las responsables del 40 por ciento de las infecciones urinarias hospitalarias. Se analizó el efecto modular de cefotaxima y ciprofloxacina en concentraciones subinhibitorias, sobre la adherencia a sondas vesicales de cepas uropatógenas de Escherichia coli. Este estudio se efectuó con cepas con bajo y elevado grado de hidrofobicidad determinados por agregación salina. Los experimentos de adherencia a sondas vesicales, en ausencia y presencia de ambos antibióticos, se realizaron a la hora y a las 24 h de contacto con los antibacterianos mencionados. El número de UFC/ml adheridas, se determinó por espectrofotometría y recuento de colonias. Se demostró que en la mayoría de las cepas con elevado grado de hidrofobicidad, aumentó el número de UFC/ml que se adhirieron a la sonda vesical, con alguno de los tratamientos. En forma inversa se comportaron las cepas con bajo grado de hidrofobicidad. El comportamiento diferente de las cepas, tratadas en las mismas condiciones, no permite generalizar el efecto de los antibióticos en concentraciones subinhibitorias, sobre la colonización bacteriana de sondas vesicales