Pseudomonas aeruginosa is a commonly encountered gram negative bacteria which is a potential source of nosocomial infections. Amongst the various acquired mechanisms of resistance, production of beta lactamases is the most common. The failure to detect this may lead to therapeutic failure and spread of resistance .This study was conducted for a period of one year from March 2016 to find out the antibiotic susceptibility pattern of the Pseudomonas aeruginosa isolates obtained from various clinical samples received, to identify the proportion of Amp C producers among the isolates, and to find out whether there is an association between antibiotic intake and the emergence of antibiotic resistance. A total of 125 Pseudomonas aeruginosa isolates were obtained, majority were from respiratory samples.  Most of the isolates (90%) were susceptible to Carbapenems. Among the 125 isolates, 110 screened positive as potential Amp C producers. Plasmid mediated Amp C production was confirmed by Boronic acid disk test whereas inducible Amp C was confirmed by disk antagonism test using Ceftazidime and the inducer, Imipenem. Out of the 110, 85 were confirmed to be Amp C producers and majority (81) were inducible Amp C producers and only 4 showed plasmid mediated Amp C production. A statistically significant association between antibiotic resistance and antibiotic usage was demonstrated. Hence steps to prevent inadvertent use of antibiotics should be taken to cut down the problem of resistance.

Keywords: Pseudomonas aeruginosa; plasmid mediated Amp C; inducible Amp C.

1. Patricia M Tille. Bailey and Scott’s diagnostic microbiology. 13th ed. South Dakota: Elsevier; 2014. 336-339 p.
2. Tapan Majumdar, Shibabrata Bhattacharya, and Raunak Bir. Prevalence of Extended Spectrum β-Lactamase and AmpC β-Lactamase among Enterobact-eriaceae and Pseudomonadaceae Isolated at Tertiary Care Set up in Tripura, India. RRJMB. 2014 Jun;3(2):19–26.
3. Subbalakshmi Easwaran, Ranjani Chittur Yerat Rajendran Ramaswamy,. A study on detection of extended-spectrum beta-lactamases (ESBLs) and comparison of various phenotypic methods of AmpC detection in Pseudomonas aeruginosa from various clinical isolates in a tertiary care teaching hospital. Muller J Med Sci Res. 2016;7:35–9.
4. Roya Rafiee,Fereshteh Eftekhar,Seyyed Ahmad Tabatabaei, Dariush Minaee Tehrani. Prevalence of Extended-Spectrum and Metallo β-Lactamase Production in AmpC β-Lactamase Producing Pseudomonas aeruginosa Isolates From Burns. Jundishapur J Microbiol. 2014 Sep;7(9).
5. Pitout JDD, Gregson DB, Poirel L, McClure J-A, Le P, Church DL. Detection of Pseudomonas aeruginosa Producing Metallo-β-Lactamases in a Large Centralized Laboratory. J Clin Microbiol. 2005 Jul 1;43(7):3129–35.
6. S Meradji, B Abouddihaj, Z Khalid, D Mazouz, H Chettibi, N Elmdaghri, M Timinouni . Epidemiology of carbapenem non-susceptible Pseudomonas aeruginosa isolates in Eastern Algeria. Antimicrobial resist and Infection Control.2015;4;27
7. Loveena OberoiNachhatarjit singh, Poonam Sharma, Aruna Aggarwal. ESBL,MBL and Ampc β Lactamases Producing Superbugs – Havoc in the Intensive Care Units of Punjab India. J Clin Diagn Res.2013Jan;7(1):70-73
8. N.A. Harris,J.K. Ferguson. Antibiotic therapy for inducible AmpC Beta lactamase-producing Gram-negative bacilli: what are the alternatives to carbapenems, quinolones and aminoglycosides? International Journal of Antimicrobial Agents. 2012;40:297–305.
9. Perforamnce standards for antimicrobial susceptibility testng.26^th ed. CLSI supplement M100. Wayne, PA:Clinical and Laboratory Standards Institute; 2010.
10. Pandey A, Rawat A, Handa S, Thakuria B, Handa D, Asthana A. Evaluation of phenotypic tests for the detection of AmpC beta-lactamase in clinical isolates of Escherichia coli. Indian J Pathol Microbiol. 2013;56(2):135.
11. Hassan A, Usman J, Kaleem F, Gill MM, Khalid A, Iqbal M, et al. Evaluation of different phenotypic methods for detection of Amp C Beta-lactamase producing bacteria in clinical isolates. J Coll Physicians Surg Pak. 2013;23(9):629–32.
12. Behera B, Mathur P, Das A, Kapil A, Sharma V An evaluation of four different phenotypic techniques for detection of metallo-β-lactamase producing Pseudomonas aeruginosa .IJMM 2008;26(3):233-237
13. Bose S,Mallick SK BS Khodke M. Inducible AmpC Beta-Lactamase Producing Pseudomonas Aeruginosa Isolated In A Rural Hospital Of Central India. Journal of Clinical and Diagnostic Research. 2009 Dec;3:1921–7.
14. Vinita Rawat, Monil Singhai, Pankaj Kumar Verma. Detection of Different β‑Lactamases and their Co‑existence by Using Various Discs Combination Methods in Clinical Isolates of Enterobacteriaceae and Pseudomonas spp. Journal of Laboratory Physicians. 2013 Jun;5(1):21–5.
15. Kumar V, Sen M R, Nigam C, Kumari S . Burden of different beta-lactamase classes among clinical isolates of AmpC-producing Pseudomonas aeruginosa in burn patients: A prospective study. Indian Journal of Critical Care Medicine. 2012 Jul;16(3):136-140
16. Mehvash Haider, Meher Rizvi, Nazish Fatima, Indu Shukla, Abida Malik. Necessity of detection of extended spectrum beta-lactamase, AmpC and metallo-beta-lactamases in Gram-negative bacteria isolated from clinical specimens. Muller J Med Sci Res. 2014 Jun;5(1):23–8.
17. Chaudhary M, Payasi A. Rising Antimicrobial Resistance of Pseudomonas aeruginosa Isolated from Clinical Specimens in India. Journal of Proteomics & Bioinformatics. 2013;6:005-009
18. Vanesa Pascual,Gabriel Ortiz,Maria Simo,Noemı´ Alonso,Javier Garau,Esther Calbo. Epidemiology and risk factors for infections due to AmpC b-lactamase-producing Escherichia coli. J Antimicrob Chemother. 70:899–904.

Dr Joana Mary Magdaline

Associate Professor in Microbiology, Government Medical College Ernakulam, Kalamassery North, Pine- 683503, Kerala, India

Phone: 9447196964, Email: This email address is being protected from spambots. You need JavaScript enabled to view it.