Metallo beta-lactamase producing pseudomonas species--a major cause of concern among hospital associated urinary tract infection.

Multidrug resistant pseudomonas strains are isolated in high frequency from urinary samples in hospitalised patients. With the occurrence of extended spectrum beta-lactamases (ESBLs) and metallo beta-lactamase (MBL)-producing Pseudomonas aeruginosa being increasingly reported worldwide, this study evaluated the resistance pattern of pseudomonad strains to carbapenam and other antipseudomonal antibiotics isolated from patients with hospital associated urinary tract infections along with clinical usefulness of various MBL screening methods (combined disc diffusion test, E-test and modified Hodge test). Presence of ESBL and AmpC beta-lactamases in the isolates was also determined. Of the 87 isolates, 81 (93.1%) were Pseudomonas aeruginosa, 4 (4.6%) were Pseudomonas putida, 2 (2.3%) were Burkholderia cepacia. Thirty-one isolates (35.6%) were resistant to imipenem and 61% of these 31 isolates, were MBL producers by combined disc diffusion test, while 48% were detected by E-test method. Overall, in 30% and 54% strains, production of AmpC and ESBL respectively was observed.