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- Alvarez, Laura, et al.
(författare)
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Peptidoglycan Remodeling by the Coordinated Action of Multispecific Enzymes
- 2014
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Ingår i: Microbial Drug Resistance. - : Mary Ann Liebert Inc. - 1076-6294 .- 1931-8448. ; 20:3, s. 190-198
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Tidskriftsartikel (refereegranskat)abstract
- The peptidoglycan (PG) cell wall constitutes the main defense barrier of bacteria against environmental insults and acts as communication interface. The biochemistry of this macromolecule has been well characterized throughout the years but recent discoveries have unveiled its chemical plasticity under environmental stresses. Non-canonical D-amino acids (NCDAA) are produced and released to the extracellular media by diverse bacteria. Such molecules govern cell wall adaptation to challenging environments through their incorporation into the polymer, a widespread capability among bacteria that reveals the inherent catalytic plasticity of the enzymes involved in the cell wall metabolism. Here, we analyze the recent structural and biochemical characterization of Bsr, a new family of broad spectrum racemases able to generate a wide range of NCDAA. We also discuss the necessity of a coordinated action of PG multispecific enzymes to generate adequate levels of modification in the murein sacculus. Finally, we also highlight how this catalytic plasticity of NCDAA-incorporating enzymes has allowed the development of new revolutionary methodologies for the study of PG modes of growth and in vivo dynamics.
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| 3. |
- Börjesson, Stefan, 1979-, et al.
(författare)
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Methicillin-resistant Staphylococcus pseudintermedius in Sweden
- 2012
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Ingår i: Microbial Drug Resistance. - : Mary Ann Liebert. - 1076-6294 .- 1931-8448. ; 18:6, s. 597-603
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus pseudintermedius is an opportunistic pathogen that is one of the most frequent causes of infections in dogs. In Europe, there are increasing reports of methicillin-resistant S. pseudintermedius (MRSP), and in Sweden, MRSP has also been more frequently isolated during recent years. However, there is limited knowledge regarding the epidemiology and genetic relationship among the Swedish isolates. This study therefore investigated the genetic relationship of MRSP isolated from companion animals in Sweden. In the study, MRSP isolates taken in the period January 2008-June 2010 from a total of 226 dogs and cats were characterized by spa typing, pulsed-field gel electrophoresis, and antimicrobial susceptibility testing. In addition, the geographical distribution of the isolates based on year of isolation and genetic typing was determined using a geographical information system. One multiresistant clonal lineage dominated among Swedish MRSP isolates, corresponding to the European winning lineage ST71-J-t02-SCCmec II-III. Furthermore, the geographical dissemination of MRSP corresponded to areas with high dog densities, centered on the three major cities in Sweden where the largest animal hospitals are situated.
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| 9. |
- Hamasuna, Ryoichi, et al.
(författare)
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In Vitro Activity of Sitafloxacin and Additional Newer Generation Fluoroquinolones Against Ciprofloxacin-Resistant Neisseria gonorrhoeae Isolates
- 2018
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Ingår i: Microbial Drug Resistance. - : Mary Ann Liebert. - 1076-6294 .- 1931-8448. ; 24:1, s. 30-34
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Tidskriftsartikel (refereegranskat)abstract
- Emergence of antimicrobial resistance in Neisseria gonorrhoeae is a major public health concern globally, and new antimicrobials for treatment of gonorrhea are imperative. In this study, the in vitro activity of sitafloxacin, a fluoroquinolone mainly used for respiratory tract or urogenital infections in Japan, and additional newer generation fluoroquinolones were determined against ciprofloxacin-resistant N. gonorrhoeae isolates. Minimum inhibitory concentrations (MICs) of ciprofloxacin, levofloxacin, moxifloxacin, sitafloxacin, pazufloxacin, and tosufloxacin against 47 N. gonorrhoeae isolates cultured in 2009 in Japan were determined by agar dilution method. The quinolone resistance-determining region (QRDR) of gyrA and parC was sequenced. The in vitro potency of sitafloxacin was substantially higher compared with all other tested fluoroquinolones. The MICs of sitafloxacin ranged from 0.03 to 0.5 mg/L for 35 ciprofloxacin-resistant N. gonorrhoeae isolates (ciprofloxacin MICs from 2 to 32 mg/L). No identified mutations in GyrA and ParC QRDR resulted in higher sitafloxacin MIC than 0.5 mg/L. Sitafloxacin had a high activity against N. gonorrhoeae isolates, including strains with mutations in DNA gyrase and topoisomerase IV, resulting in high-level resistance to ciprofloxacin and all other newer generation fluoroquinolones examined. However, it was still to a lower extent affected by GyrA and ParC QRDR mutations resulting in sitafloxacin MICs of up to 0.5 mg/L. This indicates that sitafloxacin should not be considered for empirical first-line monotherapy of gonorrhea. However, sitafloxacin could be valuable in a dual antimicrobial therapy and for cases with ceftriaxone resistance or allergy.
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| 10. |
- Hasan, Badrul, et al.
(författare)
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Fecal Carriage of Extended-Spectrum -Lactamases in Healthy Humans, Poultry, and Wild Birds in Leon, NicaraguaA Shared Pool of bla(CTX-M) Genes and Possible Interspecies Clonal Spread of Extended-Spectrum -Lactamases-Producing Escherichia coli
- 2016
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Ingår i: Microbial Drug Resistance. - : Mary Ann Liebert Inc. - 1076-6294 .- 1931-8448. ; 22:8, s. 682-687
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Tidskriftsartikel (refereegranskat)abstract
- Antibiotic-resistant bacteria are a major concern in the healthcare of today, especially the increasing number of gram-negative bacteria producing -lactamases such as extended-spectrum -lactamases (ESBLs). However, little is known about the relationship of ESBL producers in humans and domestic and wild birds, especially in a low-income setting. Therefore, we studied the fecal carriage of ESBL-producing Escherichia coli and Klebsiella pneumoniae in healthy humans, poultry, and wild birds in the vicinity of Leon, Nicaragua. Three hundred fecal samples were collected during December 2012 from humans (n=100), poultry (n=100) and wild birds (n=100). The samples were examined for ESBL-producing E. coli and K. pneumoniae, revealing the prevalence of 27% in humans, 13% in poultry, and 8% in wild birds. Further characterization of the ESBL-producing isolates was performed through polymerase chain reaction (PCR) (NDM, CTX-M), epidemiological typing (ERIC2-PCR), multilocus sequence typing, and sequencing. ESBL producers harbored bla(CTX-M-2), bla(CTX-M-15), bla(CTX-M-22), and bla(CTX-M-3) genotypes. The bla(CTX-M-15) constituted the absolute majority of ESBL genes among all samples. ERIC-PCR demonstrated highly related E. coli clones among humans, poultry, and wild birds. Clinically relevant E. coli clone ST648 was found in humans and poultry. There is a shared pool of bla(CTX-M) genes between humans and domesticated and wild birds in Nicaragua, and the results suggest shared clones of ESBL-producing E. coli. The study adds to the notion that wild birds and poultry can pick up antibiotic-resistant bacteria of human origin and function as a melting pot of resistance. Structured surveillance programs of antimicrobial resistance and a more regulated prescription of antibiotics are warranted in Nicaragua.
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