AMPC BETA LACTAMASES AMONG GRAM NEGATIVE CLINICAL ISOLATES FROM A TERTIARY HOSPITAL, SOUTH INDIA
Brazilian Journal Of Microbiology
AMPC BETA LACTAMASES AMONG GRAM NEGATIVE CLINICAL ISOLATES FROM A TERTIARY HOSPITAL, SOUTH INDIA
Palavras-chave: Gram negative organisms, drug resistance, three-dimensional technique, AmpC
Resumos Cadastrados
Resumo Inglês:
AmpC -lactamases are cephalosporinases that hydrolyze cephamycins as well as other extended-spectrum
cephalosporins and are poorly inhibited by clavulanic acid. Although reported with increasing frequency,
the true rate of occurrence of AmpC -lactamases in different organisms, including members of
Enterobacteriaceae, remains unknown. The present study was designed to determine the occurrence of
AmpC enzyme-harbouring Gram-negative clinical isolates in a tertiary care hospital in Pondicherry state,
South India. A total of 235 Gram negative clinical isolates were tested for resistance to cefoxitin, third
generation cephalosporin (3GC) antibiotics, ampicillin, amikacin, co-trimoxazole, gentamicin, meropenem
and tetracycline by disc diffusion method. Isolates found resistant to 3GC and cefoxitin were tested for the
production of AmpC -lactamases by three dimensional extraction method and AmpC disc method.
Isolates found to sensitive to 3GC were subjected to disc antagonism test for inducible AmpC production.
One hundred and thirty four (57%) strains were resistant to 3GC, among which 63(47%) were positive for
plasmid-mediated AmpC beta lactamases production. Among the 101 strains sensitive to 3GC, 23 (22.7%)
revealed the presence of inducible AmpC beta lactamases by disc approximation test. A total of 80.9%
(51/63) of screen positive isolates were detected by Amp C disc test and 93.6% (59/63) by three
dimensional extraction method. Out of the 86 AmpC producers, 67 (77.9%) were cefoxitin resistant
.Inducible AmpC was not found in Esch.coli and Klebsiella spp. The AmpC producers also concurrently
showed multidrug resistance pattern. AmpC producers were found to be prevalent in our hospital and
though three dimensional extraction test detects AmpC better, the disk test is easier to perform routinely
and is user- friendly.
