title: Extended-spectrum beta-lactamase-mediated resistance among bacterial isolates recovered from ocular infections.
abstract: OBJECTIVE
  To evaluate resistances mediated by extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases among Gram-negative bacteria recovered from ocular infections.
  
  
  METHODS
  As per the Clinical Laboratory Standards Institute M100-S-16 document, a total of 135 Gram-negative bacilli were recovered from ocular specimens and were subjected to phenotypic confirmation for ESBL production by the double-disc synergy test, cephalosporin and clavulanate combination disc test and E test, and, for AmpC β-lactamase, the modified double-disc approximation method and AmpC disc test.
  
  
  RESULTS
  In the double-disc synergy test, 21 (15.5%) isolates showed positive results against the cefpodoxime disc, 19 (14%) against cefpodoxime and cefotaxime, 15 (11%) against cefpodoxime, cefotaxime and ceftriaxone and 10 (7%) isolates were against cefpodoxime, cefotaxime, ceftriaxone and ceftazidime discs. In the cephalosporin/clavulanate combination disc test, 19 (14%) isolates showed positive results against cefotaxime with clavulanic acid and 10 (7%) isolates against ceftazidime with clavulanic acid. In the E test, 10 (7%) isolates displayed positive results against ceftazidime and 19 (14%) against cefotaxime. In the AmpC disc test for phenotypic confirmation, indentations were observed in 15 (11%) isolates with flattening also occurring in 10 (7%) isolates.
  
  
  CONCLUSIONS
  The incidences of ESBL- and AmpC β-lactamase-mediated resistances are found to be 7 and 18.5% among ocular isolates, respectively, and are more prevalent among the strains of Escherichia coli and Klebsiella pneumoniae.
authors: Department of Microbiology and Molecular Biology, Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Tirunelveli, Tamil Nadu, India. jayahar@tvl.aravind.org
authors: M
authors: M
authors: Jayahar Bharathi
authors: R
authors: R
authors: Ramakrishnan
authors: S
authors: S
authors: Ramesh
authors: N
authors: N
authors: Murugan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000378:metabolism*; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D015296:Ceftizoxime / Q000031:analogs & derivatives / Q000494:pharmacology; D002443:Ceftriaxone / Q000494:pharmacology; D018550:Cephalosporin Resistance; D002511:Cephalosporins / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D015818:Eye Infections, Bacterial / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D011446:Prospective Studies; D001618:beta-Lactamases / Q000378:metabolism*; D000097623:Cefpodoxime
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002439:Cefotaxime; D002442:Ceftazidime; D015296:Ceftizoxime; D002443:Ceftriaxone; D002511:Cephalosporins; D001618:beta-Lactamases; D000097623:Cefpodoxime; C048795:AmpC beta-lactamases