Epidemiology and characteristics of antimicrobial resistance in China.
ABSTRACT A comprehensive surveillance system for bacterial resistance in tertiary hospitals has been established in China that involves tertiary hospitals in distinct regions nationwide, enabling the collection of a large amount of antimicrobial surveillance data. Antimicrobial resistance in China has become a serious healthcare problem, with high resistance rates of most common bacteria to clinically important antimicrobial agents. Methicillin-resistant S. aureus, ESBL-producing Enterobacteriaceae and carbapenem-resistant Acinetobacter baumannii represent more than 50% of microbial isolates. Additionally, bacterial resistance to fluoroquinolones, macrolides and third-generation cephalosporins is of serious concern. The molecular epidemiology and resistance mechanisms of the antimicrobial strains in China exhibited regional specificity, as well as the influence of dissemination of international clonal complexes. The molecular characteristics of MRSA, ESBL- and carbapenemase-producing Enterobacteriaceae, and macrolide-resistant gram-positive Streptococci in China were significantly different from those in other countries and regions, while S. pneumoniae serotypes appear to have been affected by the global spread of prevalent clones in other parts of the world. Moreover, important antimicrobial resistant bacteria such as community-acquired-MRSA, multidrug-resistant P. aeruginosa and extensive-resistant A. baumannii, and the antimicrobial resistance in primary healthcare and outpatient setting should be intensely monitored and investigated in the future.
SourceAvailable from: Jianzhong Zhang
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ABSTRACT: Background In order to investigate the epidemiology, molecular characteristics, and distribution of extended-spectrum ß-lactamase (ESBL)- and AmpC-producing Escherichia coli from community-onset infections in Chinese county hospitals.Methods E. coli isolates were collected from patients with community-onset infections in 30 county hospitals. ESBL activity was confirmed by double-disc diffusion. Genetic confirmation and molecular typing of ESBL- and AmpC-producing isolates was determined by PCR and DNA sequencing. ESBL-positive isolates were further characterised by multi-locus sequence typing.ResultsOf 550 E. coli isolates, 256 (46.5%) carried ESBL genes and all were of the CTX-M type. The prevalence of ESBL-producing strains varied from 30.2% to 57.0% across different regions of China. Overall, 12 bla CTX-M subtypes were detected; the most abundant were bla CTX-M-14 (163/256 isolates, 64.5%), bla CTX-M-55(47/256, 18.4%), and bla CTX-M-15 (31/256, 12.1%). CMY-2-like AmpC ß-lactamases were detected in 11 strains, three of which co-existed with bla CTX-M. A total of 64 sequence types (STs) were detected in 256 ESBL-producing strains, including nine that were new. ST131 was the most abundant type (27 isolates, 12.7%), followed by ST69 (14 isolates, 6.6%), ST405 (14 isolates, 6.6%), and ST38 (12 isolates, 5.6%).Conclusions This study revealed that the widespread prevalence of ESBLs among outpatient infections has reached a high level in county hospitals. The CTX-M genotype was most dominant, comprising a variety of subtypes. This is the first time the incidence of CTX-M-55 has exceeded that of CTX-M-15 in China. No predominant ST was detected, suggesting that ESBL-producing E. coli strains originate in different clones.BMC Infectious Diseases 12/2014; 14(1):659. DOI:10.1186/s12879-014-0659-0 · 2.56 Impact Factor
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ABSTRACT: We describe the synthesis, characterization and photophysical properties of two new polycarboxylic photosensitizers. Owing to their structural design, these two compounds show water solubilities larger than natural carboxylic photosensitizers, (e,g. protoporphyrin IX, hematoporphyrin,…) and also good singlet oxygen quantum yields. These compounds were tested as photo-antimicrobial agents against Staphylococcus aureus and Bacillus cereus strains. Results reveal that their photocytoxicities are strongly dependent on their amphiphilic character and more precisely the number and position of the carboxylic acid and mesityl substituents.Bioorganic & Medicinal Chemistry Letters 11/2014; 25(2). DOI:10.1016/j.bmcl.2014.11.033 · 2.33 Impact Factor