Fazle Bari, Sajjad Ahmad, Hamzullah Khan


Background: Nosocomial infections are major health issues in developing as well as developed countries. The objective of this study was to determine the frequency of MBL production in Pseudomnas aeruginosa that causes resistance to Imipenem and other ß-lactam antibiotics.

Materials & Methods: A sample of 52 Imipenem resistant Pseudomnas aeruginosa colonizing or infecting the hospitalized patients were collected in Department of Pathology, Post Graduate Medical Institute, Lady Reading Hospital, Peshawar from June 2014 till May 2016. The organisms were identified by routine laboratory tests including biochemical methods and API NE System (Biomeriux) and the sensitivity pattern of commonly used antibiotics was established for each of these isolates using the disc diffusion method. Imipenem resistant strains were tested for MBL production by Imipenem-EDTA disc diffusion method.

Results: The frequency of MBL activity was positive in 39 (75%) cases of Pseudomnas aeruginosa which encodes resistance to Imipenem and other ß-lactam antibiotics except monobactam. The sensitivity pattern of these antibiotics was as follows: piperacillin/ tazobactam 30.8%, amikacin and polymyxin B each 17.9%, tobramycin 12.8%, cefoperazone/ sulbactam and ceftazidime each 5.1%, ciprofloxacin, moxifloxacin, colistin sulphate, tetracycline, azithromycin and aztreonam each 2.6% and co-trimoxzole, gentamicin & rifampin each 0%.

Conclusion: MBL production in P. aeruginosa confers a challenge for clinicians to treat such resistant infections with conventional antibiotics. Therefore testing each Imipenem resistant Pseudomnas aeruginosa for MBL production must be taken in routine consideration.


Nosocomial infections; Pseudomnas aeruginosa; ß-lactam resistant; Imipenem; Imipenem resistant strains; Antibiotics; Monobactams; Carbapenems; EDTA, Amikacin.

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Nester E, Anderson D, Roberts CE Jr, Nester M. Microbiology: A Human Perspective, 6th ed. McGraw Hill: London; 2001.pp.213-5.

Tsakris A, Pournaras S, Woodford N, Palepou MF, Babini GS, Douboyas J, et al. Outbreak of infections caused by Pseudomonas aeruginosa producing VIM-1 carbapenemase in Greece. J Clin Microbiol 2000; 38:1290-2.

Simone A, Nouer R, Nucci M, Arcia P, Oliveira D, Lucia F, et al. Risk factors for acquisition of multidrug-resistant pseudomonas aeruginosa producing SPM Metallo-β-Lactamase. Antimicrob Agents Chemother 2005; 49:3663-7.

Itto H, Arakawa Y, Ohsunka S, Kato N, Ohta M, Wacharotayankun R. Plasmid-mediated dissemination of the metallo-ß-lactamase gene blaIMP among clinically isolated strains of Pseudomonas aeruginosa. Antimicrob Agents Chemother 1995; 39:824-9.

Laura P , Colinon C, Migliavacca R, Labonia M, Docquier JD, Nucleo E, et al. Nosocomial outbreak caused by multidrug-resistant pseudomonas aeruginosa producing IMP-13 metallo-β-lactamase. J clin microbiol 2005; 43:3824-8.

Livermore DM. Multiple mechanisms of antimicrobial resistance in pseudomonas aeruginosa: our worst nightmare? Clin Infect Dis 2002; 34:634-40.

Walsh T. Tolenam MA, Poirel L, Norodmann P. Metallo-β-lactamase: the quiet before the storm? Clin Microbiol Reviews 2005; 18: 306-25.

Lee K, Lim YS, Yong D, Yum JH, Chong Y. Evaluation of the Hodge test and the Imipenem-EDTA double disc synergy test for differentiating metallo-ß-lactase producing isolates of pseudomonas aeruginosa spp. and acinobacter spp. J Clin Microbiol 2003; 41: 4623-9.

Yong D, Lee K, Yum JH, Shin HB, Rossolini GM, Chong Y. Imipenem-EDTA disc method for differentiation of metallo-β-lactamase producing clinical isolates of pseudomonas spp. and acinetobacter spp. J Clin Microbiol 2002; 40: 3798-01.

Fang D, Xi-wei XU, Wen-qi S, Ping LU, Sang-jie YU, Yong-hong Y, et al. Characterization of multidrug-resistant and metallo-beta-lactamase producing Pseudomonas aeruginosa isolates from a paediatric clinic in china. Chin Med J 2008 Sep; 121 (17): 1611-6.

Laura P , Colinon C, Migliavacca R, Labonia M, Docquier JD, Nucleo E, et al. Nosocomial outbreak caused by multidrug-resistant pseudomonas aeruginosa producing IMP-13 metallo-β-lactamase. J Clin Microbiol 2005 Aug; 43(8):3824-8.

Docquier JD, Luzzaro F, Amicosante G, Toniolo A, Rossolini GM. Multidrug resistant Pseudomonas aeruginosa PER-1 extended-spectrum serine. J Clin Microbiol 2001; 7: 517-21.

Murray BE. New aspects of antimicrobial resistance and the resulting therapeutic dilemmas. J Infect Dis 1991; 63:1185-94.

Krieg NR, Holt JG, editors. Bergey's Manual of Systematic Bacteriology. 3rd ed. Williams & Wilkins: Sydney.

Robert A, Bonomo, Szabo D. Mechanisms of multidrug resistance in acinetobacter species and pseudomonas aeruginosa. J Clin Microbiol 2008; 7: 203-5.

Gales AC, Resis AO, Jones RN. Contemporary assessment of antimicrobial susceptibility testing method for polymyxin b and colistin: review of available interpretative criteria and quality control guidelines. J Clin Microbial 2001; 39: 183-7.

Harris AD, Smith D, Johnson JA, Bradham DD, Roghmann MC. Risk factors for imipenem-resistant pseudomonas aeruginosa among hospitalized patients. Clin Infect Dis 2003; 34: 340-3.



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