Detection of Extended Spectrum Beta Lactamases Among Clinical Isolates of Pseudomonas aeruginosa

Shree Dhotre 1, Vilas Jahagirdar 2, Basavraj Nagoba 3
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1 Assistant Professor Department of Microbiology, M.M. Patel Public Charitable Trust’s, Ashwini Medical College & Hospital, Kumbhari-413006, Solapur, Maharashtra, India
2 Formerly Dean & Professor of Microbiology Govt. Medical College, Miraj, Maharashtra, India
3 Assistant Dean (R&D) & Professor of Microbiology Maharashtra Institute of Medical Sciences & Research, Latur-413 531, Maharashtra, India
EUR J BASIC MED SCI, Volume 5, Issue 3, pp. 45-50.
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Infections caused by Pseudomonas aeruginosa are tough to treat as the majority of these isolates exhibit varying degrees of beta-lactamase mediated resistance. These enzymes are capable of hydrolyzing broad spectrum cephalosporins and monobactams but inactive against cephamycins and imipenem. Resistance to broad-spectrum beta lactams, mediated by extended-spectrum beta lactamases (ESBLs), is an increasing problem worldwide. In addition, ESBL producing organism’s exhibit coresistance to several other classes of antibiotics resulting in limitation of therapeutic option. This resistance poses problems for testing and reporting. Increased prevalence of ESBLs among clinical isolates creates a great need for laboratory testing methods that will accurately identify their presence. Thus the present study was designed to investigate the prevalence of extended-spectrum beta lactamases (ESBLs) in clinical isolates of P. aeruginosa. A total of 150 clinical isolates of P. aeruginosa were isolated from various clinical samples were tested for antimicrobial susceptibility by Kirby-Baeur disk diffusion method. 75 isolates showing a zone diameter less than 18 mm to Cefoxitin (screen positive) were tested for the presence of extended spectrum beta-lactamase (ESBL) by disk approximation method using cefoxitin inducer and cefotaxime indicator method as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Antibiogram of P. aeruginosa isolates revealed that, highest resistance was observed to gentamycin (73.67%), followed by ceftazidime (70.67%), amikacin (63.33%), ciprofloxacin (52.67%) in that order of frequencies. Maximum susceptibility was observed to carbenicillin (72%). Multiple drug resistance was common phenomenon observed, in more than 50% of strains. 78 (52%) isolates showed resistance to six or more antibiotics. 65.33% of P. aeruginosa strains showed extended spectrum beta-lactamase production in (70.73%) isolates from pus followed by urine (62.5%). The study emphasizes the high prevalence of multidrug resistant P. aeruginosa producing extended spectrum beta-lactamase using a simple disk approximation method. Thus proper antibiotic policy and measures to restrict the indiscriminative use of cephalosporins and carbapenems should be taken to minimize the emergence of this multiple beta-lactamase producing pathogens.


Dhotre S, Jahagirdar V, Nagoba B. Detection of Extended Spectrum Beta Lactamases Among Clinical Isolates of Pseudomonas aeruginosa. Eur J Basic Med Sci. 2015;5(3):45-50.


  • Ambler, R. P. The structure of β-lactamases. Philos Trans R Soc Lond 1980; B 289:321–331.
  • Philippon, A., G. Arlet, and P. H. Lagrange. Origin and impact of plasmid-mediated extended-spectrum betalactamases. Eur J Clin Microbiol Infect Dis 1994;13(Suppl. 1):17–29.
  • Philippon LN, Naas T, Bouthors A-typhaine, Barakett V, Nordmann P, Be A. OXA-18, a Class D Clavulanic Acid-Inhibited Extended-Spectrum β-Lactamase from Pseudomonas aeruginosa. Antimicrob Agents Chemother 1997;41(10):2188–95.
  • Zali FHM, Chanawong A, Kerr KG, Birkenhead D, Hawkey PM. JAC Detection of extended-spectrum β-lactamases in members of the family Enterobacteriaceae: comparison of the MAST DD test, the double disc and the Etest ESBL. J Antimicrobial Chemotherapy 2000;45:881-5.
  • Chaudhary U, Aggarwal R. Extended spectrum β-lactamases ( ESBL ) – An emerging threat to clinical therapeutics. Ind J Med Microbiol 2004;22(2):75-80.
  • Revathi G, Singh S, Simrita S. Detection of expanded spectrum cephalosporin resistance due to inducible lactamases in hospital isolates. Ind J Med Microbiol 1997;15:113-115.
  • Peshattiwar PD, Peerapur BV. ESBL and MBL Mediated Resistance in Pseudomonas aeruginosa : An Emerging Threat to Clinical Therapeutics. J Clin Diagn Res 2011; 5(8): 1552-4.
  • Aggarwal R, Chaudhary U, Bala K. Detection of extended spectrum beta lactamase in Pseudomonas aeruginosa. Ind J Pathol Microbiol 2008;51: 222-224.
  • Hemlatha V, Sekar U, Kamat V. Prevalence of metallo beta lactamase producing Pseudomonas aeruginosa in hospitalized patients. Ind J Med Res 2005;122: 148-152.
  • Giriyapur RS, Nandihal NW, Krishna BVS, PatilAB, Chandrasekhar M R. Comparison of Disc Diffusion Methods for the Detection of Extended-Spectrum Beta Lactamase-Producing Enterobacteriaceae. J Lab Physicians 2011;3(1): 33-36.
  • Polsfuss S, Bloemberg GV, Giger J, Meyer V, Hombach M. Comparison of European Committee on Antimicrobial Susceptibility Testing (EUCAST) and CLSI screening parameters for the detection of extended-spectrum β-lactamase production in clinical Enterobacteriaceae isolates. J Antimicrob Chemother 2012;67(1):159-66.