The Simultaneous Detection of the ESBL and the AmpC b-Lactamases in Gram Negative Bacilli 660-663
Asst. Professor, Dept. of Microbiology,
SAIMS Medical College, Sanwer Road, Indore,
Madhya Pradesh, India - 453111
E-mail: email@example.com; firstname.lastname@example.org
Purpose: The purpose of this study was to detect the prevalence of the ESBLs and the AmpC β-lactamases in gram-negative bacilli.
Methods: The detection of ESBLs was done by using various third generation cephalosporins (3GC), along with imipenem, aztreonam, cefoxitin and ceftazidime + clavulanic acid. The criteria which were used for the identification of ESBL â€“ were resistance to 3GC, sensitivity to cefoxitin and increase in the zone size by 5 mm or more of ceftazidime + clavulanic acid as compared to the ceftazidime zone size. The organisms which were resistant to cefoxitin were tested for the presence of AmpC by the AmpC disc test.
Results: A total of 432 isolates were isolated from 414 samples. Out of these 432 isolates, 85(19.67%) were (64 pure and 21 mixed) ESBL producers, 69(15.97%) were (48 pure and 21 mixed) AmpC β-lactamase producers and 299(69.22%) isolates didnâ€™t show any evidence of the production of β-lactamases. 21(4.86%) isolates were positive for both ESBLs and AmpC. Out of the 64 pure ESBL producers, 55 (85.94%) were from indoor patients and 9(14.06%) were from outdoor patients. Out of the 48 pure AmpC producers, 42(87.5%) were from indoor patients and 6(12.5%) were from outdoor patients. All (21) the mixed beta lactamase producers (ESBLs + AmpC) were from indoor patients.
Conclusion: Regular monitoring of the incidence of the β-lactamase production by the organisms is necessary. As the β-lactamase producing organisms are also present in the outdoor patients, they also should be screened for the production of β-lactamases. The detection of ESBLs and AmpC beta lactamases by this method is simple and any microbiology laboratory can do it along with the routine antibiotic susceptibility testing.