Biology Reference
In-Depth Information
Abbreviations
MDR Multidrug-resistance
PCR Polymerase chain reaction
UPEC Uropathogenic
E. coli
UTI
Urinary tract infection
VFs
Virulence factors
9.1
Introduction
Escherichia coli
is a frequent cause of urinary tract infection (UTI) in humans and
in companion animals such as dogs and cats. This disease, often associated with
urogenital diseases, such as cystitis, nephritis, and prostatitis (Wilson et al.
1988
), is
a serious clinical problem, which is difficult to solve, and is associated with
antimicrobial resistance, the presence of virulence factors (VFs), and tissue coloni-
zation. The latter are all factors contributing, in some cases, to persistence of
infection. The majority of uropathogenic
E. coli
(UPEC) strains produce specific
VFs. Most UPEC strains are able to infect noncompromised hosts and, contrary to
intestinal strains, belong prevalently to phylogenetic group B2 and less frequently
to group D. In humans, the UPEC strains that cause UTI usually do not present high
antibiotic resistance and are associated with the presence of an elevated number of
VFs (Johnson et al.
2003
).
The aim of the present study was to assess the relationship between antibiotic-
resistance profiles, virulence genotype, and phylogenetic groups within a collection
of
E. coli
strains isolated from dogs and cats with UTI.
9.2 Material and Methods
A total of 40
E. coli
isolates from dogs (
n
10) with cystitis
were used. The urine samples were cultured on MacConkey agar (Oxoid,
Basingstoke, Hampshire, England), and lactose-fermenting, indole-positive
colonies were evaluated by the BBL Crystal test (Becton, Dickinson and Company,
USA). The isolates had been previously investigated for eight virulence markers
(
fimA
,
papC
,
cdt
,
sfa
,
afa, iutA
,
hlyA
, and
cnf1
) by polymerase chain reaction (PCR)
and assigned to phylogenetic groups (A, B1, B2, and D) by multiplex-PCR
(Tramuta et al.
2011
). Antibiotic-resistance profiles were performed using the
disk diffusion method, following the National Committee for Clinical Laboratory
Standards (
2001
). All strains were tested with antimicrobial agents on the basis
of their importance for the treatment of urinary infections on companion animals
and belonging to different classes of chemotherapeutics: gentamicin (GM),
trimethoprim-sulfamethoxazole (SXT), nitrofurantoin (NT), enrofloxacin (ENO),
30) and cats (
n
¼
¼
