Efficacy of Some Antibiotics in Curing Resistant <i>Escherichia coli</i>Infection

There is growing interest in re-evaluation of older antibiotics with the wide spread of pathogen resistance, especially gram negative bacteria, which impair treatment of some infections. In contrast various studies have reported that some antibiotics have efficacy in clearing resistant bacterial infections. On account of that it was interesting to evaluate the efficacy of erythromycin, chloramphenicol and/or tenoxicam in curing and/or relieving wound infection of highly resistant Escherichia coli and investigate the possible mechanisms beyond their antibacterial activity. This was achieved through evaluating highly resistant E. coli strains in vitro using agar dilution and in vivo rat models of E. coli infected wound and acute inflammation by carrageenin, where possible mechanisms were evaluated through measuring immunological mediators and histopathological examination. This study revealed that in vivo, erythromycin alone or in combination with tenoxicam significantly improved the healing of infected skin wounds with E. coli irresspective of resistancy in vitro. In addition to the improvement of immunological mediators involved in inflammatory reaction, oxidative stress and in cytokines expression as response to the bacterial infection in vivo. On the other hand chloramphenicol neither alone nor in combination with tenoxicam, achieved any significant effect. Tenoxicam didn’t show antimicrobial activity alone nor in combination with tested antibiotics in vitro, but it has shown synergestic activity in combination with tested antibiotics in vivo. Thus we concluded that immunomodulatory activity of erythromycin through anti-inflammatory and antioxidant effects was the possible mechanisms by which this antibiotic had healed infection with resistant E. coli in vivo, despite its resistancy to this antibiotic in vitro.

Direct-acting antivirals sofosbuvir and daclatasvir attenuate carbon tetrachloride-induced liver fibrosis in mice

Background and aim:Advanced liver fibrosis is a major risk for developing hepatocellular carcinoma(HCC)in chronic hepatitis C virus(HCV)patients.Direct-acting antivirals(DAAs)which are used for treating HCV infection,produce more than 90%cure rate but do not seem to diminish the rate of occurrence or recurrence of HCC.This study aimed to investigate the effect of DAAs sofosbuvir(SOF)and daclatasvir(DAC)on carbon tetrachloride(CCl4)-induced fibrotic changes in mice.Methods:Eighty adult male Swiss albino mice were randomly allocated into 8 groups(10 mice/group):normal control group,SOF group(receiving SOF 80 mg/kg body weight(BW),oral gavage,daily),DAC group(receiving DAC 30 mg/kg BW,oral gavage,daily),SOF t DAC group(receiving a combination of both,daily),CCl4 model group(receiving CCl42 mL/kg BW,intraperitoneal twice weekly)and three CCl4-intoxicated groups receiving either SOF or DAC or their combination.All CCl4 groups received CCl4 for 12 weeks followed by DAAs for another 12 weeks.Results:CCl4-induced a significant elevation of alanine aminotransferase(ALT)and aspartate aminotransferase(AST),and produced histopathological evidence of fibrosis and liver degeneration along with a significant increase(P0.001)of the proliferation markers(proliferating cell nuclear antigen(PCNA)and Ki-67),hepatic stellate cells(HSCs)activation markers(alpha-smooth muscle actin(a-SMA)and glial fibrillary acidic protein(GFAP)),fibrosis marker(matrix metalloproteinase-9(MMP-9))and proinflammatory cytokine(tumor necrosis factor-alpha(TNF-a)).CCl4-intoxicated mice treated with SOF,DAC,or their combination revealed a significant amelioration(P0.001)of CCl4-induced elevation of liver enzymes,fibrotic changes,and liver degeneration along with a significant attenuation(P0.001)of CCl4-induced upregulation of all tested markers.The effects of SOF,DAC,and their combination on liver enzymes were comparable while the effect of SOF t DAC combination on mitigating CCl4-induced upregulation of the proliferation and HSCs activation markers was significantly stronger than either SOF or DAC alone.As for MMP-9 and TNF-a,the effects of DAC and SOF t DAC combination were comparable and both were more significant than that of SOF alone.Conclusions:SOF and DAC may possess an antifibrotic effect that is independent of their role as antiviral agents against CCl4-induced liver injury.This might exclude the role of DAAs in early occurrence or accelerated recurrence of HCC through the progression of the HCV patients'pre-existing fibrosis.However,HCC patients treated with DAAs should be closely monitored with continuous HCC surveillance during and post-therapy.