title: Characterization of plasmid mediated AmpC producing Escherichia coli clinical isolates from a tertiary care hospital in South India.
abstract: BACKGROUND
  Plasmid mediated AmpC (pAmpC) β-lactamase producing Escherichia coli are an emerging problem worldwide as they are now exhibiting resistance to multiple classes of antibiotics and are a major cause of therapeutic failure.
  
  
  OBJECTIVE
  The aim of this study was to characterize pAmpC β-lactamase producing extraintestinal E. coli, their phylogenetic distribution, resistance pattern, treatment options, and impact on patient's clinical outcome.
  
  
  METHODS
  This descriptive study was carried out in a multi-specialty tertiary care hospital.
  
  
  METHODS
  A total of 300 clinically significant, non-repeat isolates were studied. AmpC disk test was used for phenotypic AmpC-β-lactamase detection. Molecular types of pAmpC were determined by a multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Metallo-beta-lactamase (MBL) detection was done by E test. Antibiogram, treatment, and clinical outcome were collected in a structured proforma.
  
  
  RESULTS
  Although 95 isolates (32%) were phenotypically positive for AmpC, PCR detected CIT type of AmpC gene in only 37 isolates. Majority of strains were from phylogroup A (85%) and B1 (58%) which are considered as commensal groups. Co-production of ESBL's was observed in 33 strains and 5 strains were found to be MBL producers. Most widely prescribed antibiotics were 3 rd generation cephalosporins (30%), carbapenems (19%) and aminoglycosides (16%).
  
  
  CONCLUSIONS
  Plasmid mediated AmpC producing isolates were found to exhibit a high degree of drug resistance, and they mainly belonged to commensal strains possibly due to misuse of antibiotics. Proper antibiotic policy is required to limit the spread of pAmpC producers or else it will lead to a therapeutic dead end in the near future.
authors.affiliation: Department of Medicine, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: Arindam
authors.initials: A
authors.lastname: Chakraborty
authors.forename: Prabha
authors.initials: P
authors.lastname: Adhikari
authors.forename: Shalini
authors.initials: S
authors.lastname: Shenoy
authors.forename: Vishwas
authors.initials: V
authors.lastname: Saralaya
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D006801:Humans; D007194:India; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D062606:Tertiary Care Centers; D016896:Treatment Outcome; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases