Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases
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Clin. Microbiol. Infect. · Apr 2008
Comparative StudyComparison of type III secretion system virulence among fluoroquinolone-susceptible and -resistant clinical isolates of Pseudomonas aeruginosa.
Fluoroquinolone resistance and type III secretion system (TTSS) virulence are independently associated in Pseudomonas aeruginosa infections with poor patient outcomes. In the present study, the virulence of fluoroquinolone-susceptible and -resistant isolates of P. aeruginosa was compared, focusing on TTSS virulence. Clinical isolates (n = 45) exhibiting a broad range of susceptibilities to fluoroquinolones, with differing mechanisms of resistance and associated with varying disease sites, were selected for the study. ⋯ Almost all exoU(+) strains secreted ExoU and exhibited increased cytotoxicity compared with ExoS-secreting strains (7% vs. 92.5%, relative to a PA103 reference strain control). These data suggest that exoU(+) and fluoroquinolone resistance may be co-selected traits that result in highly virulent and resistant strains. Adverse outcomes associated with infections caused by fluoroquinolone-resistant strains may, in part, be attributable to this co-association, which warrants further clinical investigation.
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The aim of antimicrobial management or stewardship programmes is to ensure proper use of antimicrobial agents in order to provide the best treatment outcomes, to lessen the risk of adverse effects (including antimicrobial resistance), and to promote cost-effectiveness. Increasingly, long-term sustainability is found to be the major focus of antimicrobial stewardship. Implementing structural measures in healthcare institutions is therefore a major, but not the sole, focus of attention in promoting prudent use of antibiotics. The problem of antimicrobial resistance requires common strategies at all levels--for the prescribers and at ward, departmental, hospital, national and international levels.
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Clin. Microbiol. Infect. · Feb 2008
ReviewMycoplasma pneumoniae-an emerging extra-pulmonary pathogen.
Mycoplasma is a well-recognised pathogen that colonises mucosal surfaces of humans and animals. Mycoplasma pneumoniae infects the upper and lower respiratory tracts of children and adults, leading to a wide range of respiratory and non-respiratory clinical conditions. ⋯ This contrasts with patients who present with non-respiratory symptoms in the context of a recent or current unrecognised M. pneumoniae infection, for whom this pathogen is rarely considered in the initial differential diagnosis. This review considers the microbiological, epidemiological, pathogenic and clinical features of this frequent pathogen that need to be considered in the differential diagnosis of respiratory and non-respiratory infections.
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Genes encoding extended-spectrum beta-lactamases (ESBLs) have been reported in a variety of Gram-negative species, mostly in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. They are mostly either TEM or SHV derivatives, CTX-M-like enzymes--now emerging worldwide--or, less frequently, VEB, GES, and PER ESBLs. The mechanisms responsible for their acquisition are very diverse, and mostly are related to insertion sequences (ISs), transposons, class 1 integrons, and also sul1-type integrons containing the ISCR1 element. This diversity of genetic vehicles at the origin of these mobilisation/acquisition processes enhances the spread of ESBLs.
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Among the many different structurally distinct classes of beta-lactams, the carbapenem class is regarded as that which is most potent and which has the widest spectrum of antimicrobial activity. Rapidly bactericidal, and demonstrating time-dependent killing, carbapenemes have a spectrum of antimicrobial activity that includes Gram-positive and Gram-negative aerobic and anaerobic pathogens. ⋯ Imipenem, meropenem and ertapenem are licensed in the European Community and panipenem and biapenem are also available in Japan and South Korea. Other carbapenemes are under development.