First Report of OXA-4, an ESBL Isolated from Pseudomonas aeruginosa a South Indian Strain

Abstract

The OXA-type b-lactamases are so named because of their oxacillin-hydrolyzing abilities. In this study we characterize an extended spectrum b-lactamase, designated OXA-4, produced by a clinical isolate of Pseudomonas aeruginosa. ESBL production was detected by double disk synergy test. The P. aeruginosa isolate was obtained from endotracheal suction tip of 84 years old male patient diagnosed with CVA and hypertension. ESBL producing OXA b-lactamases was detected by PCR with primers specific to the conserved regions of the coding genes. Iso electric focusing was done to confirm the significance, sequencing the amplified product was also done. In the phenotypic identification, the strain was highly resistant to third generation cephalosporins and also to imipenem. The PCR amplified product for OXA b-lactamase was viewed at 919 bp. The pI point for the same was identified at 7.2. With the help of sequencing the amplified OXA b-lactamase was identified as OXA-4 gene. Here we report P. aeruginosa producing OXA-4 ESBL for the first time in the Indian subcontinent.

ESBL producing Pseudomonas aeruginosa in clinical specimens: Is it a scary nightmare or paper tiger?

“…Several oxacillinases (OXA-2 and OXA-10 derivatives and OXA-18) that have extended substrate profiles, including extended spectrum cephalosporin, have been reported in P. aeruginosa.OXA-ESBLs are mutants of OXA-2 and OXA -10, belonging to the molecular class D of Ambler's scheme and 2d of functional group under Bush-Jacoby-Medeiros classification whereas the other ESBL belongs to class A. Recently, P. aeruginosa producing OXA-4 ESBL for the first time in the Indian subcontinent was also reported (3) .…”

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“…(18.1%), and Haemophilus influenzae (4.9%) and gram-positive bacteria such as Staphylococcus aureus (18%) 2 . P. aeruginosa is a frequently isolated pathogen from the clinical sample of hospitalized patients thus is responsible for a high percentage of infections 3 . This bacterium shows antibiotic resistance, by developing membrane impermeability, efflux pump systems and changes in drug targets thus posing a huge remedial problem [4][5][6] .…”