Escherichia coli is one of the Gram negative bacterium from the family Enterobacteriaceae. It is a
member of the normal intestinal flora but some strains carry virulence factors, which cause extraintestinal
infections, infections of the urinary tract in particular. One of the mechanisms of the
antimicrobial resistance is the production of enzymes, which hydrolyze beta-lactam antibiotics.
Enzymes capable of transmitting bacterial resistance to penicillins, first-, second-, and thirdgeneration
cephalosporins, and aztreonam have arisen called extended-spectrum betalactamases
(ESBL). They cause hospital- and community-acquired infections. Due to this, studies
were conducted on risk factors concerning infections with these organisms. ESBL-producing
Enterobacteriacea are a major global problem.
The studies found an increased occurrence of these bacteria in the Pomurje region in 2005. The
extent of the problem lessened by the year 2008 because of defensive measures, but the number
of ESBL-producing E. coli has dramatically increased in 2009. Most isolates were isolated from
urine.
Forty-nine patients were included in the retrospective study. Patients were from different acute
wards from the General Hospital of Murska Sobota, ESBL-producing E. coli from urine was isolated
in all of them. 71.4 % of the patients were female; the average age of the group was 70.6 years.
We have observed accordance of dosage and the length of therapy for every antimicrobial drug
with guidelines and Summary of Product Characteristics for every patient. We have observed
higher accordance of dosage with regard to both references. Accordance of the therapy length
was mostly inappropriate according to guidelines, and we could not assess therapy length
regarding to Summary of Product Characteristics in most cases.
Not every patient received antimicrobial therapy because of urinary tract infections, hence we
were unable to assess therapy in accordance to the microbiological tests. The bacteria were
sensitive on the empirical therapy in 16.7 % of the cases. Antimicrobial therapy was changed in
45.8 % of the cases, and they have not changed the antimicrobial drug on which were resistant
bacteria in 16.7 %. If the resistance to certain chemotherapeutic agent is higher than 10-20 %,
empirical treatment is problematic. When a significant portion of Gram negative bacteria in a
particular unit produce ESBL, empirical therapy turns toward the use of carbapenems, quinolones
or combination of beta-lactams and beta-lactamase inhibitors. When we examined the sensitivity,
we observed that ESBL-producing E. coli is completely resistant to penicillins, first-, second-, and
third-generation cephalosporins, highly resistant to fluoroquinolones and gentamicin. It is
sensitive to carbapenems but resistance is already apparent to ertapenem.
Most probable of the potential risk factors include: female gender, advanced age, immobility,
cardiovascular diseases, presence of urinary catheter, hospitalization in the last year, prior
antimicrobial therapy. Most of the patients returned home, the portion of fatal outcomes was
20.4 %, three patients died because of urinary tract infections with resistant bacteria and/or
urosepsis among them; that amounts to 6.1 % of the observed group.
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