Variability of laboratory identification and antibiotic susceptibility reporting of pseudomonas spp. isolates from dogs with chronic otitis externa
Variability of laboratory identification and antibiotic susceptibility reporting of Pseudomonas spp. isolates from dogs with chronic otitis externa Anthea E. Schick*, John C. Angus† Agreement in susceptibility to individual antibiotics and Kimberly S. Coyner* was observed in 13 of 16 (81%) occasions for amikacin and gentamicin, 10 of 16 (63%) occasions for ticarcillin,
*Dermatology Clinic for Animals, Gilbert, Arizona, USA
and nine of 16 (56%) for enrofloxacin. These results
†Southern Arizona Veterinary Specialty and Emergency Center,
indicate that Pseudomonas spp. were identified by all three laboratories chosen for this study in 83% of the
Correspondence: Anthea E. Schick, 86 West Juniper Dr., Gilbert, AZ
time. Moreover, antibiotic susceptibility patterns and
85233, USA. E-mail: antheaschick@gmail.com. MIC values reported to veterinarians may not agree between laboratories. Veterinarians should interpret bacterial culture and susceptibility results with multi- What is known about the topic of this paper ple caveats including variability between laboratories. • Pseudomonas otitis is an important secondary cause of • Veterinarians rely on correct identification and consistent
antimicrobial susceptibility of Pseudomonas for soundtreatment of Pseudomonas otitis. What this paper adds to the field of veterinary dermatology Introduction
• This study demonstrates interlaboratory variability in identi-
fication of Pseudomonas and variability in susceptible
Canine otitis externa is a common condition encountered
versus resistant classification to various antimicrobials
in small animal medicine. Common organisms isolated
that may affect selection of therapy.
from dogs with otitis externa include Staphylococcus spp.,Pseudomonas spp., Proteus spp., Streptococcus spp.,Escherichia coli, Klebsiella spp., Bacteroides spp., Pas-teurella spp. and Malassezia spp.1,2 The recommended
Abstract
management of canine otitis externa consists of identi-
The purpose of this study was to evaluate interlabo-
fying and treating the predisposing factors and primary
ratory variation in isolation and antibiotic susceptibility
disease, ear cleaning, topical therapy and, if indicated, sys-
pattern of Pseudomonas spp. as reported to veteri-
temic antimicrobial medication.3 Culture and antimicrobial
narians for cases of canine chronic bacterial otitis
susceptibility testing are recommended in severe or chronic
externa. Twenty-six dogs with unilateral or bilateral
cases of otitis externa, when rod-shaped bacteria are
bacterial otitis externa from multiple referral practices
present, when inflammatory cells are present on cytology,
were included in this prospective study. Triplicate
or in cases that fail to respond to antimicrobials chosen
samples collected simultaneously from the same loca-
empirically.4–6 Pseudomonas aeruginosa is an aerobic,
tion in the external ear canal were randomly sub-
gram-negative bacillus, which is associated with chronic
mitted to three laboratories for culture and susceptibility
otitis externa and otitis media and often displays resist-
testing. Pseudomonas spp. were isolated from 18 of 34
ance to multiple antimicrobial drugs.1,7 Because of this
(53%) ears. All three laboratories agreed on the pres-
resistance, veterinarians may focus on susceptibility
ence of Pseudomonas spp. in 15 (83.3%) ears sampled.
patterns of Pseudomonas spp. when multiple organisms
However, two laboratories agreed on two (11.1%)
are isolated. Accurate bacterial identification and consistent
occasions, and on one occasion (5.5%) Pseudomonas
antibiotic susceptibility reporting are important for proper
spp. were identified in only one laboratory. Minimum
antimicrobial drug choice by veterinarians. inhibitory concentration (MIC) susceptibilities to 11
Several studies have evaluated the microbial isolates and
antibiotics were compared between laboratories B
antimicrobial susceptibility patterns of dogs with otitis.1,8,9
and C. Using laboratory-defined susceptibility of
One study found that Pseudomonas spp. isolated from
sensitive (S), intermediate (I) and resistant (R), none
the horizontal ear canal had different susceptibility profiles
of the 16 Pseudomonas spp. with MIC data reported
from Pseudomonas spp. isolated from the middle ear in 75%
had identical patterns of antibiotic susceptibility.
of the time.1 A study comparing samples taken from thesame location in the ear canal and submitted to the samecommercial laboratory found that 70% of the P. aeruginosa
This study was presented at the North American Veterinary
cases had different susceptibility profiles suggesting that
there may be multiple strains of Pseudomonas spp. inhabiting
2007 The Authors. Journal compilation 2007 ESVD and ACVD. 18; 120–126 Pseudomonas susceptibility between laboratories
the ear canal of dogs with Pseudomonas otitis.8 Another study
All three laboratories followed the guidelines set by the Clinical and
comparing bacterial isolates and their antimicrobial sus-
Laboratory Standards Institute (CLSI), formerly the National Committee
ceptibility patterns from parallel cultures submitted to the
same laboratory found that 11% of P. aeruginosa isolateshad different susceptibility patterns and that cytopathology
Bacterial culture and antimicrobial susceptibility
agreed with the culture results in 68% of the time.9 These
methods All samples were received by the laboratories within 24 h of collection.
studies raise the question of the reproducibility of cultureand susceptibility testing in canine Pseudomonas otitis.
Many veterinarians utilize the culture and antimicrobial
Samples were plated on blood agar and MacConkey’s agar, cultured
susceptibility reports from laboratories to select antimicrobial
at 37 °C overnight with carbon dioxide enhancement and observed for
drugs for both topical and systemic therapy of otitis. Incon-
growth the following day. Following incubation, microbes were iden-
sistencies in identification and antimicrobial susceptibility
tified by colonial morphology, size and zones of haemolysis, pigment
patterns of Pseudomonas spp. between laboratories can
production, growth inhibition and differences in reactions. Once a
affect antibiotic choice and, subsequently, treatment outcome
pure culture was obtained, a sterile cotton tip swab was touched tothree to five colonies and suspended in saline solution to a uniform
of dogs with Pseudomonas otitis. The purpose of this study
turbidity of 0.5 McFarland. The Trek Sensititre® (TREK Diagnostic
was to determine whether reports of Pseudomonas spp.
Systems, Inc., Cleveland, OH, USA) automated machine was used to
identification and antimicrobial susceptibility patterns from
measure the minimum inhibitory concentration (MIC). A 50-µL loop
clinical cases of otitis externa were consistent between two
was used to inoculate Mueller–Hinton broth, then equal volumes of
major commercial laboratories and one academic laboratory.
the culture were manually pipetted into each of the 96-well agarplate of serially diluted antibiotics. Turbidity of samples was readby Sensititre ARIS® (TREK Diagnostic Systems, Inc.) machine for
Materials and methods Study population
Cases were selected from a population of client-owned dogs presented
Samples were plated and identified as for laboratory A. Once a pure
to a private veterinary dermatology referral practice with multiple
culture was obtained, a sterile cotton tip swab was touched to one to
locations in the south-western and western USA. Dogs with chronic
two colonies and suspended in saline solution to a uniform turbidity
otitis externa, defined as persistent or intermittent unilateral or bilateral
of 0.1 McFarland. VITEK® (VITEK bioMerieux, Inc., Durham, NC,
otitis of at least 6 months duration, were selected for the study. Bacterial
USA) automated machine was used to measure MIC. A uniform
otitis was diagnosed by clinical assessment and cytological criteria
volume of the culture was machine-pipetted and added to serial
characterized by greater than 10 bacteria per 1000× magnification
dilutions of the antibiotics being tested. The samples were incubated
present in a minimum of five fields.11 Dogs with rod-shaped bacteria
for 2–24 h, with samples automatically read for turbidity of growth at
found on cytological evaluation were included in the study. The pres-
15-min intervals. A growth curve for the isolate was calculated for each
ence or absence of leucocytes was also noted. Cytological evidence
antibiotic. The algorithm stored in the VITEK® (VITEK bioMerieux, Inc.)
of a concurrent Malassezia otitis did not exclude a dog from the study.
system analysis program calculated the organisms’ MIC for each of
Additionally, dogs that had been receiving treatment with systemic
or topical antibiotics at the time of evaluation were not excluded, asthe goal of the study was to compare bacterial culture results and
antimicrobial susceptibility patterns between different microbiology
Samples were plated on Columbia blood, MacConkey’s, and
laboratories under typical clinical practice circumstances.
Columbia colistin Nalidixic acid agar plates, incubated at 37 °Covernight and observed for growth the following day. Following
Sample collection and randomization for bacterial
incubation, microbes were identified as for laboratory A. Once a pureculture was obtained, a sterile cotton tip swab was touched to one
culture and antimicrobial susceptibility
colony and suspended in saline solution to a uniform turbidity of
Samples for otic cultures were obtained by passing a gas-sterilized
0.5 McFarland. The Trek Sensititre® automated machine was used
disposable ear cone into the external canal and visualizing the junction
to measure MIC. A uniform volume of the culture 10 µL of solution
of the vertical and horizontal ear canal. Three sterile minitip cul-
was manually pipetted into each of the 96-well Mueller–Hinton
turette swabs (Mini-tip Culturette, Becton-Dickinson, Cockeysville,
agar plate of serially diluted antibiotics. Turbidity of samples was read
MD, USA) were passed simultaneously through the ear cone, forming
by Sensitouch® (TREK Diagnostic Systems, Inc., Cleveland, OH, USA)
a three-prong cluster emerging from the end of the cone tip. The three
culturettes were rotated and rubbed together to equally distribute theexudate on each culturette. Thereafter, each swab was placed into a
Statistical analyses
separate sterile culture transport tube (Mini-tip Culturette, Becton-Dickinson) for aerobic bacterial culture and antibiotic susceptibility.
Sign test was used to investigate distributions of MIC values
Samples were randomly assigned to one of three laboratories by
between laboratories B and C for four antibiotics considered effective
labelling each sample A, B, and C. Using a die, laboratory A (Antech
in treating Pseudomonas otitis, including amikacin, enrofloxacin, genta-
Microbiology Laboratory, Irvine, CA, USA) was assigned the values of
micin and ticarcillin. Since laboratory B failed to report MIC data for
1 and 4, laboratory B (IDEXX Reference Laboratory, West Sacra-
ticarcillin in one sample, this sample was not included in the comparison.
mento, CA, USA) the values of 2 and 5, and laboratory C (Veterinary
Differences were considered significant at P < 0.05.
Diagnostic Laboratory, College of Veterinary Medicine, University ofIllinois, Urbana, IL, USA) the values of 3 and 6. A die was rolled for the
first sample and the sample was sent to the laboratory correspondingwith the value on the die. That laboratory was then eliminated as a
Twenty-six dogs were found to have bacterial otitis externa
choice, and the die was rolled until a number representing one of the
with rod-shaped bacteria present on cytology and were
two remaining labs was obtained. The third sample was sent to the
included in the study. Eighteen dogs had one ear sampled
remaining laboratory. Samples submitted to laboratories A and B weretransported by the standard courier service provided by each labora-
for culture and antimicrobial susceptibility and eight dogs
tory. Samples submitted to laboratory C were sent next day by air by
had both ears sampled, resulting in a total of 34 ears
tested. Triplicate samples were collected from all 34 ears
2007 The Authors. Journal compilation 2007 ESVD and ACVD. Schick et al.
resulting in a total of 102 samples submitted for bacterial
MIC susceptibility results for the 16 cases for laboratories
B and C are shown in Table 1. Both laboratories performeda full range of MICs. Dilutions of antimicrobials tested and
Bacterial culture results
the MIC breakpoint for resistance for laboratories B and C
Pseudomonas aeruginosa or Pseudomonas spp. were
isolated by at least one of the three laboratories in culture
Direct comparison of reported specific MIC results
samples from 18 of 34 (53%) ears and in 50 of 102 (49%)
was only possible between laboratories B and C. Since the
total samples. Laboratory A isolated Pseudomonas spp. in
majority of the antibiotics included on the panels from
16 of the 34 ear samples, while laboratories B and C each
both laboratories are ineffective for Pseudomonas spp.,13
isolated Pseudomonas spp. from 17 ears. Bacteria other
only the antibiotics that have been reported to be effective
than Pseudomonas spp. were isolated from 16 ear samples.
in treating Pseudomonas spp. otitis were used in the
All three laboratories agreed on isolating Pseudomonas
comparison tests. The distributions for MIC values for
spp. in samples collected from 15 of the 18 (83.3%) ears.
amikacin and enrofloxacin were not significantly different
In two occasions (11.1%), Pseudomonas spp. were iso-
between laboratory B and laboratory C (P = 0.21 and
lated by only two laboratories and, in one occasion (5.5%),
P = 0.61, respectively). The MIC values for gentamicin
by only one laboratory. Pseudomonas aeruginosa was
and ticarcillin reported by laboratory B were significantly
consistently identified by the laboratories with the excep-
higher than the MIC values reported by laboratory C
tion of three occasions where the species was not reported
(P = 0.023 and P = 0.001, respectively). Discussion Antimicrobial susceptibility patterns Although the tube dilution testing with MIC results was
Veterinarians frequently rely on culture and susceptibility
requested on the submission form sent to all laboratories,
testing from otic swabs to select antibiotic therapy for
some isolates were tested using the Kirby–Bauer (KB)
bacterial otitis externa. Repeatability and reliability of
disk diffusion method for determining antimicrobial sus-
laboratory results are desirable to minimize administra-
ceptibility. Laboratory A reported KB results for five of the
tion of inappropriate antibiotics. This study demonstrated
16 Pseudomonas spp. Isolates, while laboratories B and C
inconsistency between laboratories in isolation of Pseu-
reported MIC data for all 17 Pseudomonas spp. isolates. domonas spp. and in antimicrobial susceptibility patterns
Because of the differences between the KB and the MIC
for Pseudomonas spp. reported for otic swabs submitted
methods of susceptibility testing,13,14 KB data were not
from clinical cases. When one laboratory isolated Pseu-
included in the comparison of antimicrobial susceptibility
domonas spp., at least one of the other laboratories failed
pattern. As a result, laboratory A susceptibility data were
to isolate Pseudomonas spp. in 16.7% of cases. As Pseu-
not analysed because of the small number of isolates
domonas otitis can be one of the most challenging types
of otitis often associated with antibiotic resistance,3 failure
MIC data for 11 antibiotics common to the antimicrobial
to consistently isolate Pseudomonas spp. by laboratories
panels of laboratories B and C were compared including
may lead to inappropriate therapy decisions and more
amikacin, amoxycillin/clavulanic acid, ampicillin, first-
prolonged disease course for affected animals.
generation cephalosporin (cefalexin and cephalothin),
One possible reason for failure of all three laboratories
third-generation cephalosporin (ceftiofur), chloramphenicol,
to consistently isolate Pseudomonas spp. in this study
enrofloxacin, gentamicin, tetracycline, ticarcillin and tri-
is the presence of very small numbers of organisms in
methoprim/sulfamethoxazole. Using laboratories B and
the samples submitted for culture. All dogs included in the
C’s reported antimicrobial susceptibility of sensitive (S),
present study had active, chronic otitis with abundant otic
intermediate (I) and resistant (R), none of the 16 Pseu-
exudate. All dogs with positive cultures for Pseudomonasdomonas spp. Isolates, in which MIC data were provided
spp. had numerous bacterial rods present on cytology,
for all tested antimicrobials from both laboratories, had
making the possibility of inadequate samples less likely.
the same antibiotic susceptibility patterns. For amoxycillin/
Also, rotating and rubbing the culturettes together should
clavulanic acid and first-generation cephalosporin, both
have distributed organisms among the three culturettes.
laboratories reported resistance for all 16 isolates. The
Other possible reasons for failure of all laboratories to iso-
laboratories agreed on resistance to chloramphenicol
late Pseudomonas include variation in sample processing,
for 14 of the 16 (88%) Pseudomonas spp. isolates. For
variation in culture technique, and error inherent to culture
ampicillin, ceftiofur, and tetracycline, both laboratories
methods. All laboratories received the samples within the
agreed on resistance for 13 (81%) isolates. Resistance
same time period and used similar culturing techniques,
to trimethoprim/sulfamethoxazole was reported by both
using both blood agar and MacConkey’s agar to grow the
laboratories in 11 of the 16 (69%) tested isolates. For
initial cultures. As different laboratories have different
amikacin and gentamicin, the laboratories agreed that the
laboratory technicians, there could have been differences
cultured Pseudomonas spp. isolates were susceptible in
in plating techniques or identification of Pseudomonas
Laboratory B reported KB data for ticarcillin susceptibility
Laboratory A reported KB susceptibility data for five of
in one occasion and these data were not included in the
the16 isolates despite the specific request by the sub-
comparison. Both laboratories agreed on whether the
mitting veterinarian for MIC determination. A previous study
Pseudomonas spp. isolates were resistant or susceptible
examining the differences between these two testing
to ticarcillin and enrofloxacin in nine of 15 (60%) occasions.
methods showed that for susceptibility of Pseudomonas
2007 The Authors. Journal compilation 2007 ESVD and ACVD.
2007 The Authors. Journal compilation 2007 ESVD and ACVD. Table 1. Susceptibility results based on minimal inhibitory concentration of 11 antibiotics tested against Pseudomonas spp. isolates sampled from the ear canals of dogs with chronic otitis externa R ≥ 32 R ≥ 16 R ≥ 8 R ≥ 16 R ≥ 32 R ≥ 256 R ≥ 320 S ≤ 0.25 R > 16 R ≥ 320 R ≥ 320 R ≥ 32 R ≥ 32 R ≥ 8 R ≥ 2 R ≥ 16 R ≥ 256 S ≤ 0.25 R ≥ 2 Pseudomonas R ≥ 256 R ≥ 2 R ≥ 16 susceptibility between laboratories R ≥ 2
Minimum inhibitory concentration (MIC) expressed in µg mL−1; S, sensitive (MIC lower than the breakpoint for the drug); I, intermediate (MIC close to or equal to the breakpoint for the drug); R, resistant (MIC greater than the breakpoint for the drug); S ≤ indicates that no smaller dilution was tested, R > and R ≥ indicates that no higher dilution was tested; S or R indicates that a discrete endpoint was achieved; values in bold indicate disagreement in laboratory-defined susceptibility status; *Kirby–Bauer disk diffusion method was used. Schick et al. Table 2. Dilutions of antimicrobials tested and minimum inhibitory
submitted sample but only one strain selected by the
concentration breakpoints for resistance for laboratories B and C
laboratory for susceptibility testing. Additionally, hetero-resistance may exist among a single strain. The term
heteroresistant is most commonly used for vancomycin-
2, 4, 8, 16, 32, 64
4, 8, 16, 32, 64
resistant Staphylococci spp. and refers to variability in
8/4, 16/8, 32/16
antibiotic susceptibility among subpopulations of a single
0.25, 0.5, 1, 2, 4, 8, 16, 32 0.5, 1, 2, 4, 8, 16
isolate.16 A heteroresistant isolate contains two popula-
0.25, 0.5, 1, 2, 4
tions of cells, one that is susceptible to a certain antibiotic
Cefalexin/cephalothin 2, 4, 8, 16, 32
2, 4, 8, 16
and a minority population that is resistant.16 If only a few
2, 4, 8, 16, 32
colonies are chosen for MIC evaluation, the laboratory
0.25, 0.5, 1, 2
0.5, 1, 2, 4
may report resistance patterns of only one subpopulation.
0.5, 1, 2, 4, 8, 16
1, 2, 4, 8, 16
Significant difference in distribution of MIC values
1, 2, 4, 8, 16
reported by laboratories B and C was shown for gentamicin
16, 32, 64, 128, 256
8, 16, 32, 64
10, 20, 40, 80, 160, 320*
and ticarcillin, but not for amikacin and enrofloxacin. For
gentamicin and ticarcillin, MIC values from laboratory Bwere higher than those from laboratory C and explained
All values in ug mL−1; values in bold indicate breakpoint for resistance. Laboratory B: IDEXX Reference Laboratory, West Sacramento, CA,
the disparate laboratory-defined susceptibility results (i.e.
sensitive, intermediate, resistant) for both antibiotics. For
Laboratory C: Veterinary Diagnostic Laboratory, College of Veterinary
enrofloxacin, MIC values from laboratory B were also
Medicine, University of Illinois, Urbana, IL, USA.
generally higher than those from laboratory C and explained
*Trimethoprim/sulfamethoxazole expressed as combined
five of the seven disparate laboratory-defined susceptibility
trimethoprim + sulfamethoxazole fractions.
results. The finding of quantitative differences in MIC report-ing suggests that when given duplicate samples from thesame ear Pseudomonas spp. susceptibility and MIC patterns
spp. to enrofloxacin, KB and MIC results agreed only one
may differ between laboratories for some antimicrobials.
third of the time.13 A second study found that KB results
Differences in MIC values between laboratories B and
tended to yield a more conservative clinical interpretation
C may have been due to different MIC testing methods.
than MIC results; meaning KB method may underestimate
Laboratory B used the Vitek® automated machine, whereas
susceptibility.14 Veterinarians should know which tech-
laboratory C used the Trek Sensititre® automated machine
nique their laboratory employed, as well as understand the
to measure MIC values. A study published in 1987 com-
differences in methodology and how this methodology
paring seven commonly used antimicrobial susceptibility
influences the interpretation of antimicrobial susceptibility.
methods to test 150 isolates of P. aeruginosa found no
Susceptibility patterns were compared between labo-
significant differences between the Sensititre® and the
ratories B and C for 16 Pseudomonas spp. isolates. Of the
Vitek® methods for aminoglycosides;17 however, fluoro-
relevant antibiotic choices for treating Pseudomonas
quinolones and ticarcillin were not tested.
otitis, which typically include amikacin, enrofloxacin, genta-
Results from this study demonstrate variability between
micin, and ticarcillin, complete agreement between the
two major commercial laboratories and an academic labo-
two laboratories for these four antibiotics was found
ratory in isolation of Pseudomonas spp. Moreover, sub-
only in three (19%) occasions. Both laboratories reported
sequent antimicrobial susceptibility data for the isolates
susceptibility to amikacin and gentamicin for 81% of the
were occasionally discrepant between two of the labora-
Pseudomonas spp. isolates, whereas the agreement for
tories. Veterinarians need to be aware of possible laboratory
ticarcillin was 60% and for enrofloxacin 56%.
variability in the isolation of Pseudomonas spp. from otic
The variability in the report of enrofloxacin susceptibility
cultures as well as differences in antimicrobial susceptibility
between laboratories B and C could be partially explained
reporting that may result from variability in MIC determina-
by differences in using CLSI-recommended enrofloxacin
tions and possible differences in antibiotic breakpoints used.
breakpoint values for evaluating susceptibility patternsof Pseudomonas spp. isolates. In this study, laboratory B
Acknowledgements
used an MIC breakpoint for enrofloxacin of 2 µg mL−1,whereas laboratory C used 4 µg mL−1. CLSI changed
The authors would like to thank David J. Schaeffer, from
the breakpoint for enrofloxacin from 2 to 4 µg mL−1 in
University of Illinois at Urbana-Champaign, College of
1999.12 Of the seven ears sampled that resulted in con-
Veterinary Medicine for statistical analysis, Tom Lewis,
flicting susceptibility data from laboratories B and C, four
Helen Power, and Amy Shumaker, for their help with this
of them may have agreed that laboratory B used the
study as well as Bayer Animal Health for funding.
higher MIC breakpoint. A Pseudomonas organism that is‘resistant’ using a breakpoint of 2 µg mL−1, the drug con-
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Résumé
Le but de cette étude était d’évaluer la variabilité interlaboratoire pour l’isolement et les anti-
biogrammes en rapport avec Pseudomonas spp. Retrouvé dans les cas d’otite canine chronique. Vingt sixchiens à otite externe bactérienne, uni ou bilatérale, de diverses clientèles référées, ont été inclus dans cetteétude prospective. Les prélèvements ont été réalisés en triple, et soumis au hasard à trois laboratoires pourculture et antibiogramme. Pseudomonas spp. A été isolé de 18 sur 34 (53%) oreilles. Les trois laboratoiresétaient d’accord sur la présence de Pseudomonas spp. dans 15 (83.3%) oreilles. En revanche, deux labo-ratoires étaient en accord dans 2 cas (11.1%) et dans un cas (5.5%) Pseudomonas spp. a été identifié parun seul laboratoire. Les concentrations minimales inhibitrices (MIC) à 11 antibiotiques ont été comparéesentre les laboratoires B et C. En se basant sur les sensibilités définies comme sensible (S), intermédiaire(I) et résistant (R), aucune des 16 souches de Pseudomonas spp. présentaient des sensibilités identiques. Un accord sur la sensibilité aux antibiotiques individuels a été observée dans 13 sur 16 (81%) cas pourl’amikacine et la gentamicine, 10 de 16 (63%) cas pour la ticarcilline, et 9 de 16 (56%) cas pour l’enro-floxacine. Ces résultats indiquent que Pseudomonas spp. A été identifié par les trois laboratoires choisispour cette étude dans 83% des cas. En outre, les sensibilités antibiotiques et les valeurs de MIC donnéesaux vétérinaires ne sont pas toujours les mêmes en fonction des laboratoires. Les vétérinaires doivent doncinterpréter avec précaution les résultats des antibiogrammes et des cultures bactériologiques réalisés enpratique.
El propósito de este estudio fue evaluar la variación interlaboratorial en el aislamiento y suscep-
tibilidad a antibióticos de Pseudomonas spp. en casos de otitis bacteriana externa crónica canina. Veintiseisperros con otitis externa unilateral o bilateral procedentes de diversas clínicas de referencia se incluyeronen este estudio prospectivo. Muestras triplicadas recogidas simultaneamente de la misma localización enel canal auditivo externo se remitieron a tres laboratorios de forma aleatoria para la realización del cultivo ysusceptibilidad. Pseudomonas spp. se aisló de 18 de 34 oídos (53%). Todos los laboratorios coincidieronen la presencia de Pseudomonas en 15 (83.3%) de los oídos cultivados. Sin embargo sólo dos laboratorioscoincidieron en 2 ocasiones (11.1%), y en una ocasión (5.5%) Pseudomonas spp. se aisló unicamente enuno de los laboratorios. La susceptibilidad a la concentración inhibitoria mínima (MIC) para once antibióticosse comparó entre los laboratorios B y C. Utilizando parametros de susceptibilidad definidos por el laboratoriocomo sensible (S), intermedio (I) o resistente (R), ninguna de las 16 Pseudomonas spp. con datos de MICdocumentados presentaron un perfil idéntico de susceptibilidad a antibióticos. Una coincidencia en lasusceptibilidad a antibióticos individuales se observó en 13 de 16 (81%) de los casos para amikacina ygentamicina, 10 de 16 (63%) para ticarcilina, y 9 de 16 para enrofloxacina. Estos resultados indican que Pseu-domonas spp. se identificó en los 3 laboratorios en un 83% de los casos. Más aún, los perfiles de sensibilidadantibiótica y valores de MIC indicados a los veterinarios pueden ser diferentes entre laboratorios. Losveterinarios clínicos deben interpretar los resultados del cultivo y la susceptibilidad con ciertos interrogantes,incluidos la variación entre laboratorios.
2007 The Authors. Journal compilation 2007 ESVD and ACVD. Schick et al. Zusammenfassung
Das Ziel dieser Studie war es, eine Variation zwischen den Laboratorien bei der
Isolierung von Pseudomonas spp. und Erstellung eines Antibiogramms, welches bei Fällen von chronischerbakterieller Otitis externa bei Hunden an die Tierärzte gesendet wird, zu evaluieren. SechsundzwanzigHunde aus mehreren Überweisungspraxen mit uni- oder bilateraler bakterieller Otitis externa wurden indieser prospektiven Studie inkludiert. Die Proben wurden gleichzeitig in dreifacher Ausführung von derselbenStelle im äußeren Gehörgang entnommen und wahllos an drei Laboratorien für Bakterienkultur undErstellung eines Antibiogramms geschickt. Pseudomonas spp. wurde von 18 der 34 (53%) Ohren isoliert. Alle drei Laboratorien stimmten im Bezug auf ein Vorhandensein von Pseudomonas spp. in 15 (83,3%) derkultivierten Ohren überein. Allerdings stimmten nur zwei Laboratorien in 2 (11,1%) Fällen überein, währendPseudomonas spp. einmal nur von einem Labor identifiziert wurde. Die minimale inhibitorische Konzentra-tion (MIC) für elf Antibiotika wurde zwischen den Laboratorien B und C verglichen. Bei Verwendung der vonden Laboratorien definierten Empfindlichkeiten als sensitiv (S), intermediär (I) und resistent (R) zeigte keinerder 16 Pseudomonas spp. mit vorhandenen MIC Daten ein identisches Muster im Bezug auf die anti-biotische Empfindlichkeit. Eine Übereinstimmung für individuelle Antibiotika wurde bei 13 der 16 (81%) Fällefür Amikacin und Gentamycin, bei 10 der 16 (63%) Fälle für Ticarcillin, und bei 9 der 16 (56%) Fälle für Enro-floxacin beobachtet. Diese Ergebnisse weisen darauf hin, dass Pseudomonas spp. in 83% der Fälle von allendrei Laboratorien, die für diese Studie ausgewählt worden waren, identifiziert wurde. Außerdem kann esvorkommen, dass die Ergebnisse der Antibiogramme und die MIC Daten, die an die Tierärzte weitergegebenwerden zwischen den Labors nicht übereinstimmen. Tierärzte sollten die Ergebnisse von Bakterienkulturund Antibiogrammen mit viel Vorsicht interpretieren und die Variabilität zwischen Labors beachten.
2007 The Authors. Journal compilation 2007 ESVD and ACVD.
In October, 1996, Hartford Hospital became the first hospital in Connecticut with a Bloodless Medicine and Surgery Program. Our uses of safe and effective transfusion free medical and surgical techniques reduce many of the risk associated with blood transfusions. Through a multidisciplinary approach to patient care, complex procedures such as cardiac surgery, aortic aneurysm repa
C H A P T E R 8 THE IMPACT OF PARENTAL MENTAL ILLNESS ON SUPERVISED VISITATION Introduction Supervised visitation programs receive case referrals involving parents with mental illnesses. Sometimes themental health status of the parent is known at the time of the referral; it may in fact be a factor in theremoval of children from a parent. In other cases, however, no mention of the i