Sandbox Reserved 994: Difference between revisions

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== Background ==

OXA-24 is a member of the carbapenem-hydrolyzing class D β-lactamases (CHDLs) and is expressed as a resistance mechanism by the bacteria ''Acinetobacter baumannii.'' Class D β-lactamases are clinically dangerous because they hydrolyze β-lactam antibiotics such as penicillins, cephalosporins, and carbapenems. Class D β-lactamases are classified as OXAs, which is in reference to their class designation as oxacillinases, however the terminology is somewhat misleading. While they do have a strong affinity for the antibiotic oxacillin<ref name="Leonard">DOI: 10.1021/ar300327a</ref>~~, since their discovery~~, the OXAs have expanded to include penillinase, cephalosporinase, and carbapenemase activity in their spectrum. Due to their original designation as oxacillinases, however, the assignment of the prefix OXA has continued to be standard designation.

OXA-24 is a member of the carbapenem-hydrolyzing class D β-lactamases (CHDLs) and is expressed as a resistance mechanism by the bacteria ''Acinetobacter baumannii.'' Class D β-lactamases are clinically dangerous because they hydrolyze β-lactam antibiotics such as penicillins, cephalosporins, and carbapenems. Class D β-lactamases are classified as OXAs, which is in reference to their class designation as oxacillinases, however the terminology is somewhat misleading. While they do have a strong affinity for the antibiotic oxacillin<ref name="Leonard">DOI: 10.1021/ar300327a</ref>, the OXAs have expanded to include penillinase, cephalosporinase, and carbapenemase activity in their spectrum. Due to their original designation as oxacillinases, however, the assignment of the prefix OXA has continued to be standard designation.

''Acinetobacter baumannii'' is a strain of bacteria which has developed resistance to a large number of β-lactams by expressing OXA-24 β-lactamase. ~~This~~ resistant bacteria was involved in a nosocomial outbreak in Spain.<ref name = AB> Bou, German, Antonio Oliver, and Jesus Martinez-Beltran. "OXA-24, a Novel Class D β-Lactamase with Carbapenemase Activity in an ''Acinetobacter Baumannii'' Clinical Strain." Antimicrobial Agents and Chemotherapy 44, no. 6 (2000): 1556-561. Accessed February 19, 2015. http://aac.asm.org/content/44/6/1556.full</ref> Currently, this enzyme is inhibited by chloride ions, tazobactam, sulbactam, and clavulanic acid, and it specifically counteracts benzylpenicillin and cephaloridine.<ref name = AB /> Resistance to these inhibitors is beginning to develop due to their similarity to OXA-24's usual β-lactam substrate, and the discovery of a non β-lactam based inhibitor is critical.

''Acinetobacter baumannii'' is a strain of bacteria which has developed resistance to a large number of β-lactams by expressing OXA-24 β-lactamase. In 1997, this resistant bacteria was involved in a nosocomial outbreak in a hospital in Spain.<ref name = AB> Bou, German, Antonio Oliver, and Jesus Martinez-Beltran. "OXA-24, a Novel Class D β-Lactamase with Carbapenemase Activity in an ''Acinetobacter Baumannii'' Clinical Strain." Antimicrobial Agents and Chemotherapy 44, no. 6 (2000): 1556-561. Accessed February 19, 2015. http://aac.asm.org/content/44/6/1556.full</ref> Currently, this enzyme is inhibited by chloride ions, tazobactam, sulbactam, and clavulanic acid, and it specifically counteracts benzylpenicillin and cephaloridine.<ref name = AB /> Resistance to these inhibitors is beginning to develop due to their similarity to OXA-24's usual β-lactam substrate, and the discovery of a non β-lactam based inhibitor is critical.

== Structure ==

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 == Background ==
-OXA-24 is a member of the carbapenem-hydrolyzing class D β-lactamases (CHDLs) and is expressed as a resistance mechanism by the bacteria ''Acinetobacter baumannii.'' Class D β-lactamases are clinically dangerous because they hydrolyze β-lactam antibiotics such as penicillins, cephalosporins, and carbapenems. Class D β-lactamases are classified as OXAs, which is in reference to their class designation as oxacillinases, however the terminology is somewhat misleading.  While they do have a strong affinity for the antibiotic oxacillin<ref name="Leonard">DOI: 10.1021/ar300327a</ref>, since their discovery, the OXAs have expanded to include penillinase, cephalosporinase, and carbapenemase activity in their spectrum. Due to their original designation as oxacillinases, however, the assignment of the prefix OXA has continued to be standard designation.
+OXA-24 is a member of the carbapenem-hydrolyzing class D β-lactamases (CHDLs) and is expressed as a resistance mechanism by the bacteria ''Acinetobacter baumannii.'' Class D β-lactamases are clinically dangerous because they hydrolyze β-lactam antibiotics such as penicillins, cephalosporins, and carbapenems. Class D β-lactamases are classified as OXAs, which is in reference to their class designation as oxacillinases, however the terminology is somewhat misleading.  While they do have a strong affinity for the antibiotic oxacillin<ref name="Leonard">DOI: 10.1021/ar300327a</ref>, the OXAs have expanded to include penillinase, cephalosporinase, and carbapenemase activity in their spectrum. Due to their original designation as oxacillinases, however, the assignment of the prefix OXA has continued to be standard designation.
-''Acinetobacter baumannii'' is a strain of bacteria which has developed resistance to a large number of β-lactams by expressing OXA-24 β-lactamase. This resistant bacteria was involved in a nosocomial outbreak in Spain.<ref name = AB> Bou, German, Antonio Oliver, and Jesus Martinez-Beltran. "OXA-24, a Novel Class D β-Lactamase with Carbapenemase Activity in an ''Acinetobacter Baumannii'' Clinical Strain." Antimicrobial Agents and Chemotherapy 44, no. 6 (2000): 1556-561. Accessed February 19, 2015. http://aac.asm.org/content/44/6/1556.full</ref> Currently, this enzyme is inhibited by chloride ions, tazobactam, sulbactam, and clavulanic acid, and it specifically counteracts benzylpenicillin and cephaloridine.<ref name = AB /> Resistance to these inhibitors is beginning to develop due to their similarity to OXA-24's usual β-lactam substrate, and the discovery of a non β-lactam based inhibitor is critical.
+''Acinetobacter baumannii'' is a strain of bacteria which has developed resistance to a large number of β-lactams by expressing OXA-24 β-lactamase. In 1997, this resistant bacteria was involved in a nosocomial outbreak in a hospital in Spain.<ref name = AB> Bou, German, Antonio Oliver, and Jesus Martinez-Beltran. "OXA-24, a Novel Class D β-Lactamase with Carbapenemase Activity in an ''Acinetobacter Baumannii'' Clinical Strain." Antimicrobial Agents and Chemotherapy 44, no. 6 (2000): 1556-561. Accessed February 19, 2015. http://aac.asm.org/content/44/6/1556.full</ref> Currently, this enzyme is inhibited by chloride ions, tazobactam, sulbactam, and clavulanic acid, and it specifically counteracts benzylpenicillin and cephaloridine.<ref name = AB /> Resistance to these inhibitors is beginning to develop due to their similarity to OXA-24's usual β-lactam substrate, and the discovery of a non β-lactam based inhibitor is critical.
 == Structure ==