Comparison between combined disk test and double disc synergy test in detecting extended spectrum beta-lactamases in Klebisiela Pneumoniae

Abstract

Introduction: The spread of ESBL producing Klebisiella pneumoniae are causing more severe infections and multidrug resistance because of their continuous mutation making treatment with antibiotics difficult. Therefore there is an interest to determine more sensitive, reliable and low cost method. The study is carried out to compare combined disc test and the double disc synergy test so as to detect ESBL in Klebisiella pneumoniae. Method: a total of 16 K.pneumoniae isolates (10 esbl producers and 6 non esbl producers) were obtained from the MakCHS microbiology laboratory and cultured on chocolate agar. These were confirmed for ESBL production by the CDT and DDST. Analysis of the results was done using Microsoft Excel 2013 with the sensitivity and the specificity being calculated and compared for both methods. Results: Of the 10 ESBL producing isolates, 100% (10/10) were confirmed by CDT and 90% (9/10) by DDST. Both methods had a specificity of 100% of the 6 non-ESBL producing isolates. Conclusion: The CDT method was more sensitive than the DDST method in the detection of ESBL but both had equal specificity for ESBL detection in k.pneumoniae. This allows accurate and immediate clinical decisions for prescribing antibiotics for treatment.