CERCETÃRI PRIVIND PRODUCEREA DE BETA-LACTAMAZE CU SPECTRU EXTINS LA TULPINI DE ENTEROBACTERII
Abstract
Aim: To evaluate the susceptibility
of extended spectrum beta-lactamase (ESBL) producing organisms among Escherichia coli and
Klebsiella pneumoniae, isolated between January-October 2009 from hospital and community.
Materials and methods: From 611 enterobacteria strains, for 112 strains (E. coli, n=84 and
K. pneumoniae, n=28), the ESBL phenotypic confirmation was performed with double disk
test (DDT) and the replacement disk method. The minimum inhibitory concentrations (MICs)
for next antimicrobial agents tested: ceftazidime, cefotaxime, ceftriaxone, cefepime, cefpirome,
imipenem, meropenem, ertapenem, moxifloxacin, gatifloxacin, levofloxacin, ofloxacin were
performed by agar dilution method. Resistance rates were reported using the Clinical Laboratory
Standard Institute (CLSI) breakpoints for the fully susceptible category; moderately
susceptible isolates were classified as resistant. K. pneumoniae ATCC 700603 and E. coli
ATCC 25922 were used for quality control. Results: Resistance rates for ceftazidime,
cefotaxime, ceftriaxone and aztreonam among tested strains were very high: 84.5%, 100%,
100% and 96.4% for E. coli and 98.8%, 98.8%, 97.6% and 89.2% for K. pneumoniae, with
the MIC90 values > 256 mg/L for either antimicrobial tested agent. The MICs for fourth
generation cephalosporins ranges from 4 mg/L to 512 mg/L. The MICs for tested quinolones
were > 2 mg/L for 89.2% strains. Using breakpoint for susceptibility, all isolates were
sensitive to ertapenem, imipenem and meropenem. Conclusions: We noticed a high resistance
rate for ceftazidime, cefotaxime, ceftriaxone and aztreonam. In this study, carbapenems demonstrated
the highest degree of activity
References
Rev 2005; 18: 657-686.
2. Livermore DM. Carbapenemases. J Antimicrob Chemother 1992; 29: 609-616.
3. Moland ES, Kim SY, Hong SG, Thomson KS. Newer beta-lactamases: clinical and laboratory
implications, part I. Clin Microbiol Newsletter 2008; 30 (10): 71-77.
4. Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests
for bacteria that grow aerobically. Approved standard M07-A8 and Informational Supplement
M100-S19, 2009; vol. 29. National Committee for Clinical Laboratory Standards, Wayne, Pa.
5. Poiata A, Tuchiluº C, Grigore L et al. Enterobacteriaceae resistance in Eastern Romania: trends for 40 years
period. 9th Scientific Meeting of the European Society of Chemotherapy Infectious Diseases, 2002; 18.
6. Azap OK, Arslan H, Serefhanoglu K et al. Risk factor for extended-spectrum beta-lactamase
positivity in uropathogenic Escherichia coli isolated from community-acquired urinary tract
infections. Clin Microbiol Infect 2010; 16(2): 149-151.
7. Hal Jones C, Tuckman M, Keeney D, Ruzin A, Bradford P. Characterization and sequence
analysis of extended-spectrum beta-lactamase-encoding genes from Escherichia coli, Klebsiella
pneumoniae and Proteus mirabilis isolates collected during tigecycline phase 3 clinical trials.
Antimicrob Agents Chemother 2009; 53: 465-475.
8. Rodriguez-Bano J, Nava MD, Romero I, et al. Epidemiology and clinical features of infectious
caused by extended-spectrum beta-lactamase-producing Escherichia coli in nonhospitalized patients.
J Clin Microbiol 2004; 42: 1089-1094
9. Mugnaioli C, Luzzaro F, De Luca F et al. CTX-M-type extended-spectrum beta-lactamasess in
Italy: molecular epidemiology of an emerging countrywide problem. Antimicrob Agents Chemother
2006, 50: 2700-2706.
10. Pournaras S, Ikonomidis A, Sofianou D et al. CTX-M-type beta-lactamases affect community
Escherichia coli treatment, Greece. Emerg Infect Dis 2004: 10: 1163-1164.
11. Woodford N, Ward ME, Kaufmann ME et al. Community and hospital spread of E. coli producing
CTX-M extended-spectrum beta-lactamases in the UK. J Antimicrob Chemother 2004; 54: 735-743.

COPYRIGHT
Once an article is accepted for publication, MSJ requests a transfer of copyrights for published articles.
COPYRIGHT TRANSFER FORM FOR
REVISTA MEDICO-CHIRURGICALĂ A SOCIETĂȚII DE MEDICI ȘI NATURALIȘTI DIN IAȘI /
THE MEDICAL-SURGICAL JOURNAL OF THE SOCIETY OF PHYSICIANS AND NATURALISTS FROM IASI
We, the undersigned authors of the manuscript entitled
_____________________________________________________________________________________
_____________________________________________________________________________________
warrant that this manuscript, which is submitted for publication in the REVISTA MEDICO-CHIRURGICALĂ, has not been published and it is not under consideration for publication in another journal.
- we give the consent for publication in the REVISTA MEDICO-CHIRURGICALĂ, in printed and electronic format and we transfer unconditioned and complete the copyright of this manuscript to the REVISTA MEDICO-CHIRURGICALĂ, in the event of its acceptance.
- the manuscript does not break the intellectual property rights of any other person.
- we have read the submitted version of the manuscript and we are fully responsible for the content.
Names and signatures of authors / copyright owners (the following sequence is the authorship of the article):
- ______________________________/_________________________
- ______________________________/_________________________
- ______________________________/_________________________
N.B. All the authors must sign this form