Reduced Ertapenem Susceptibility Due to OXA-2 Production in Klebsiella pneumoniae ST258. (4th October 2017)

• Record Type: Journal Article
• Authors: Iovleva, Alina; Mettus, Roberta; McElheny, Christi; Pasculle, Anthony; Doi, Yohei
• Is Part Of: Open forum infectious diseases. Volume 4(2017)Supplement 1
• Page Start: S128
• Page End: S128
• Publication Date: 2017-10-04
• Subjects: Communicable diseases -- Periodicals; Medical microbiology -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.1093/ofid/ofx163.176
• Languages: English
• ISSNs: 2328-8957

Abstract

Abstract: Background: OXA-2 is a class D β-lactamase which is primarily found in E. coli (Ec) and P. aeruginosa and confers resistance to penicillins as well as narrow-spectrum cephalosporins. However, recent reports suggest that OXA-2 also possesses carbapenem hydrolyzing activity. We report a case of K. pneumoniae that confers reduced susceptibility to ceftazidime and ertapenem due to production of OXA-2. Methods: K. pneumoniae (Kp) strain YDC787 was identified from the BAL culture of an inpatient in December 2016. The strain was initially reported as intermediate to ertapenem. MICs and carbapenemase production were confirmed by Etest and modified Hodge test (MHT) respectively. Ec TOP10 was transformed with purified plasmids followed by selection with ampicillin (TOP10 [pYDC787]), and the carbapenem resistance determinant was cloned into vector pBCSK using partial Sau3AI digestion (TOP10 [pOXA-2]). Results: Kp YDC787, Ec TOP10 (pYDC787), and Ec TOP10 (pOXA-2) all showed reduced susceptibility to ertapenem and ceftazidime, but not meropenem, imipenem, or cefepime. All isolates were positive for carbapenemase production by MHT. Sanger sequencing of pOXA-2 revealed 2, 910-bp partial class 1 integron containing DaacA4 - bla OXA-2 - qacED1 - Dsul1. The presence of bla OXA-2 was confirmed by PCR in Kp YDC787 and Ec TOP10 (pYDC787). Conclusion: These findings confirm that OXA-2 functions as carbapenemase and cephalosporinase, significantly reducing susceptibility to ertapenem and ceftazidime, but not to meropenem, imipenem, or cefepime. Disclosures: All authors: No reported disclosures.