Title:Association of Risk Factors, Antimicrobial Resistance Trends and Occurrence of blaTEM, bla SHV and blaCTX M in Escherichia coli Causing Bacteremia
VOLUME: 16 ISSUE: 2
Author(s):Richa Sinha, Sphurti Kamath and Suchitra M. Shenoy
Affiliation:Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka 575001, India.
Keywords:Antibiotic pattern, Bloodstream infection, Escherichia coli, Risk factors.
Abstract:Purpose: Escherichia coli are the most frequent cause of gram negative bloodstream
infection. This study was done to evaluate the association of risk factors, antimicrobial
susceptibility pattern and detection of TEM, SHV and CTX M genes in the extended
spectrum beta lactamase (ESBL) producing E.coli.
Materials and Methods: 11,133 blood samples were processed in BacT/Alert bottles. Bacteria
grown were identified and antibiotic susceptibility patterns were studied using VITEK2
system. ESBL production was tested using phenotypic method, VITEK system and by PCR. Statistical package
SPSS Version 11.5 was used to do the analysis.
Results: Blood culture positive isolates were 1530 (13.7%), among which 108 were identified as Escherichia
coli. The most common risk factor associated with E.coli bacteremia was diabetes and common source was
UTI. E.coli were resistant to Ampicillin (86%), Piperacillin (82.4%), Ceftazidime (80.6%), Ceftriaxone
(80.6%), Cefipime (77%), Aztreonam (80.6%) and Fluoroquinolones (80%). Isolates were sensitive to Carbapenems
and combination drugs. ESBL was produced by 76%. CTX M bla (betalactamase) gene was common
in all the ESBL isolates.
Conclusion: ESBL producing E.coli isolates were observed to be multi drug resistant. Owing to the high
prevalence of ESBL.Carbapenems are clearly the drug of choice for empirical treatment in these
cases.Ertapenem may be used to prevent development of carbepenem resistant pseudomonas or acinetobacter
isolates in the hospital settings. To limit the earlier development of resistance to carbepenems, it is better to
de-escalate to combination drugs like piperacillin tazobactum with aminoglycosides after the susceptibility
report.
