Infections caused by non-tuberculous mycobacteria and multidrug-resistant Mycobacterium tuberculosis are difficult to treat. New compounds potentially active against these bacteria are therefore constantly being sought. Among them is grepafloxacin, a new C5 fluoroquinolone. A panel of 130 isolates of mycobacteria including 33 M. tuberculosis isolates and 97 isolates of different species of atypical mycobacteria were analysed for susceptibility to grepafloxacin, ofloxacin and ciprofloxacin. The MICs of these fluoroquinolones were determined using the agar-dilution method. Different mycobacterial species showed different degrees of susceptibility to grepafloxacin, ofloxacin and ciprofloxacin but little difference was observed between the MICs of the three antibiotics against strains of the same mycobacterial species. In addition, to evaluate the intracellular activity of these drugs, six strains of mycobacteria were studied using a human-macrophage infection model. Preliminary results of macrophage experiments showed that grepafloxacin was more active than ofloxacin and ciprofloxacin, particularly against Mycobacterium kansasii and, to a lesser degree, against Mycobacterium avium complex and Mycobacterium marinum. However, the three fluoroquinolones had comparable activities against M. tuberculosis.

Human pharmaceuticals, such as nonsteroidal anti-inflammatory drugs (NSAIDs), are an emerging threat to marine organisms. NSAIDs act through inhibition of cyclooxygenase (COX) conversion of arachidonic acid into prostaglandins. One experiment was carried out whereby marine mussels were exposed for 72 h to 1 and 100 μg/L diclofenac (DCF). A specific and sensitive method using liquid chromatography high-resolution tandem mass spectrometry was developed to quantify DCF in mussel tissues. The developed method could also clearly identify and quantify COX products, i.e., prostaglandin levels, and be used to assess their modulation following DCF exposure. Prostaglandin-D (PGD) was always found below the detection limit (20 μg/kg dry weight (dw)). Basal prostaglandin-E (PGE) concentrations ranged from below the detection limit to 202 μg/kg dw. Exposure of 100 μg/L resulted in a significant reduction in PGE levels, whereas a downward trend was observed at 1 μg/L exposure. No difference was observed for prostaglandin-Fα (PGF) levels between controls and exposed organisms.

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