Chemiluminescence methods for the determination of ofloxacin

Ofloxacin is a synthetic fluoroquinolone antibiotic that has been used in the treatment of respiratory tract, urinary tract and tissue-based infections. Methodology for the determination of ofloxacin based on chemiluminescence detection can be divided into: direct oxidation with tris(2,2′-bipyridyl)ruthenium(III) or permanganate; and enhancement of the emission from either the oxidation of sulfite or the reaction between sodium nitrite and hydrogen peroxide. In this paper, we compare the analytical methodology and evaluate the light-producing pathways that have been proposed for these reactions.

Successful outcomes with oral fluoroquinolones combined with rifampicin in the treatment of Mycobacterium ulcerans : an observational cohort study

Background: The World Health Organization currently recommends combined streptomycin and rifampicin antibiotic treatment as first-line therapy for Mycobacterium ulcerans infections. Alternatives are needed when these are not tolerated or accepted by patients, contraindicated, or neither accessible nor affordable. Despite in vitro effectiveness, clinical evidence for fluoroquinolone antibiotic use against Mycobacterium ulcerans is lacking. We describe outcomes and tolerability of
fluoroquinolone-containing antibiotic regimens for Mycobacterium ulcerans in south-eastern Australia.

Methodology/Principal Findings: Analysis was performed of prospectively collected data including all primary Mycobacterium ulcerans infections treated at Barwon Health between 1998 and 2010. Medical treatment involved antibiotic use for more than 7 days; surgical treatment involved surgical excision of a lesion. Treatment success was defined as complete lesion healing without recurrence at 12 months follow-up. A complication was defined as an adverse event attributed to an antibiotic that required its cessation. A total of 133 patients with 137 lesions were studied. Median age was
62 years (range 3–94 years). 47 (34%) had surgical treatment alone, and 90 (66%) had combined surgical and medical treatment. Rifampicin and ciprofloxacin comprised 61% and rifampicin and clarithromycin 23% of first-line antibiotic
regimens. 13/47 (30%) treated with surgery alone failed treatment compared to 0/90 (0%) of those treated with combination medical and surgical treatment (p,0.0001). There was no difference in treatment success rate for antibiotic combinations containing a fluoroquinolone (61/61 cases; 100%) compared with those not containing a fluoroquinolone (29/29 cases; 100%). Complication rates were similar between ciprofloxacin and rifampicin (31%) and rifampicin and clarithromycin (33%) regimens (OR 0.89, 95% CI 0.27–2.99). Paradoxical reactions during treatment were observed in 8 (9%) of antibiotic treated cases.

Conclusions: Antibiotics combined with surgery may significantly increase treatment success for Mycobacterium ulcerans infections, and fluoroquinolone combined with rifampicin-containing antibiotic regimens can provide an effective and safe oral treatment option.

Sequence type 131 fimH30 and fimH41 subclones amongst escherichia coli isolates in Australia and New Zealand

The clonal composition of Escherichia coli causing extra-intestinal infections includes ST131 and other common uropathogenic clones. Drivers for the spread of these clones and risks for their acquisition have been difficult to define. In this study, molecular epidemiology was combined with clinical data from 182 patients enrolled in a case-control study of community-onset expanded-spectrum cephalosporin-resistant E. coli (ESC-R-EC) in Australia and New Zealand. Genetic analysis included antimicrobial resistance mechanisms, clonality by DiversiLab (rep-PCR) and multilocus sequence typing (MLST), and subtyping of ST131 by identification of polymorphisms in the fimH gene. The clonal composition of expanded-spectrum cephalosporin-susceptible E. coli and ESC-R-EC isolates differed, with six MLST clusters amongst susceptible isolates (median 7 isolates/cluster) and three clusters amongst resistant isolates, including 40 (45%) ST131 isolates. Population estimates indicate that ST131 comprises 8% of all E. coli within our population; the fluoroquinolone-susceptible H41 subclone comprised 4.5% and the H30 subclone comprised 3.5%. The H30 subclone comprised 39% of all ESC-R-EC and 41% of all fluoroquinolone-resistant E. coli within our population. Patients with ST131 were also more likely than those with non-ST131 isolates to present with an upper than lower urinary tract infection (RR=1.8, 95% CI 1.01-3.1). ST131 and the H30 subclone were predominant amongst ESC-R-EC but were infrequent amongst susceptible isolates where the H41 subclone was more prevalent. Within our population, the proportional contribution of ST131 to fluoroquinolone resistance is comparable with that of other regions. In contrast, the overall burden of ST131 is low by global standards.