Year : 2011 | Volume
: 3 | Issue : 1 | Page : 33--36
Comparison of disc diffusion methods for the detection of extended-spectrum beta lactamase-producing Enterobacteriaceae
Ravi S Giriyapur1, Namratha W Nandihal2, BVS Krishna3, Asha B Patil2, MR Chandrasekhar4
1 Department of Microbiology, PES Institute of Medical Sciences and Research, Kuppam, Andhra Pradesh, India
2 Department of Microbiology, Karnataka Institute of Medical Sciences, Hubli, Karnataka, India
3 Department of Microbiology and Infection Control, University Hospital of North Staffordshire NHS Trust, Central Pathology Laboratories, Hartshill Road, Stoke on Trent ST4 7PX, United Kingdom
4 Department of Microbiology, Belgaum Institute of Medical Sciences, Belgaum, Karnataka, India
Background: Resistance to broad-spectrum β lactams, mediated by extended-spectrum β lactamases (ESBLs), is an increasing problem world wide. This resistance poses problems for in vitro testing and reporting. Increased prevalence of ESBLs among Enterobacteriaceae creates a great need for laboratory testing methods that will accurately identify their presence.
Materials and Methods: During the study, the Enterobacteriaceae isolated were tested for the presence of ESBL by the National Committee for Clinical Laboratory Standards (NCCLS) screening test, Jarlier double disc synergy (approximation) test (DDST) and NCCLS phenotypic confirmatory test (PCT), and compared their efficiency in detection.
Results: A total of 313 Enterobacteriaceae were isolated and tested for the presence of ESBL. NCCLS PCT identified 200 (63.89%) as ESBL producers and DDST identified 176 (56.23%), with a P-value of <0.001. Among the screening agents, ceftazidime had a better sensitivity (89.49%) and specificity (95.74%).
Conclusions: Close monitoring of the susceptibility pattern of isolates and careful spacing with specific discs can identify many ESBL producers. Ceftazidime has a better sensitivity and specificity as a screening agent. A combination of different tests can be useful for accurate identification.
Ravi S Giriyapur
Department of Microbiology, PES Institute of Medical Sciences and Research, Kuppam, Andhra Pradesh
|How to cite this article:|
Giriyapur RS, Nandihal NW, Krishna B, Patil AB, Chandrasekhar M R. Comparison of disc diffusion methods for the detection of extended-spectrum beta lactamase-producing Enterobacteriaceae.J Lab Physicians 2011;3:33-36
|How to cite this URL:|
Giriyapur RS, Nandihal NW, Krishna B, Patil AB, Chandrasekhar M R. Comparison of disc diffusion methods for the detection of extended-spectrum beta lactamase-producing Enterobacteriaceae. J Lab Physicians [serial online] 2011 [cited 2013 May 25 ];3:33-36
Available from: http://www.jlponline.org/article.asp?issn=0974-2727;year=2011;volume=3;issue=1;spage=33;epage=36;aulast=Giriyapur;type=0