105 / 264
more recent reports have documented
Pseudomonas
infection
less frequently, with
Pseudomonas
cultured in as few as 27%
to 54% of cases.
5-7
Given the increasing frequency of nonpseudomonal
MOE, we decided to retrospectively review our clinical
experience with MOE and specifically compare clinical pre-
sentations, management, and outcomes of this infection
between cases caused by
Pseudomonas
and MRSA. We
hypothesized that the clinical presentation would be similar,
regardless of the causative organism, and that treatment
might be prolonged when caused by MRSA or other non-
Pseudomonas
organisms.
Methods
Institutional review board approval was obtained for this retro-
spective study (University of Pittsburgh institutional review
board approval #PRO12010268, principal investigator Andrew
A. McCall). The University of Pittsburgh Medical Center
Department of Otolaryngology clinical record database was
searched for all patients diagnosed with MOE between 1995
and 2012. Diagnosis was confirmed by the documented pres-
ence of the all of the obligatory Cohen criteria with 2 modifi-
cations.
10
First, it is generally our practice to obtain computed
tomographic (CT) scans in lieu of nuclear medicine studies to
confirm the presence of MOE.
11
We therefore included
patients with documented evidence of bony erosion on CT
scans in place of the obligatory Cohen criterion of either posi-
tive results on a technetium-99 scan or failure of local therapy.
Second, because of the retrospective nature of the study, in
some cases, not all of the obligatory clinical criteria were
documented for each patient. We accepted patients into the
present cohort who were missing documentation of no more
than 1 of the clinical signs or symptoms of the obligatory
Cohen criteria, as has been done by others.
12
Resolution of
infection was based on the absence of clinical signs or symp-
toms of disease and the absence of radiographic progression of
disease after a minimum follow-up period of 1 month after the
completion of antibiotic therapy. Microsoft Excel 2011
(Microsoft Corporation, Redmond, Washington) and GraphPad
Prism 6 (GraphPad Software, San Diego, California) were
used for data management and statistical analysis. Statistical
comparisons between groups were performed using Fisher’s
exact test and Student’s
t
test as appropriate, and statistical sig-
nificance was set at
P
\
.05.
Results
Demographics
Twenty patients were identified from the database with sup-
porting documentation that permitted confirmation of the
diagnosis of MOE. The mean age at diagnosis was 65 years
for all patients, 62 years for
Pseudomonas
-infected patients,
and 63 years for MRSA-infected patients. There were 12
men and 8 women (
Table 1
).
Culture Data
Culture and sensitivity data were documented for all 20
patients. The means of obtaining culture data and therapy
prior to culture are documented in
Table 2
. There were 9
patients (45%) whose cultures grew
P aeruginosa
. There
was no documented ciprofloxacin resistance in any of the
Pseudomonas
specimens; 1
Pseudomonas
isolate was resis-
tant to levofloxacin. Two patients had cultures that grew
methicillin-sensitive
S aureus
in addition to
Pseudomonas
.
Three patients (15%) had cultures that grew MRSA in the
absence of
Pseudomonas
. One patient infected with MRSA
also grew
Klebsiella
and another grew pan-resistant
Acinetobacter
spp. One MRSA isolate was resistant to clin-
damycin; there was no documented resistance to doxycy-
cline, trimethoprim-sulfamethoxazole, or vancomycin.
In the 5 remaining patients with positive cultures, the fol-
lowing organisms were documented (often in a polymicro-
bial fashion):
Enterococcus
spp (n = 2), methicillin-
sensitive
S aureus
(n = 1),
Candida
spp (n = 1),
Aspergillus
(n = 1),
Staphylococcus lugdunensis
(n = 1),
Lactobacillus
(n = 1),
Peptostreptococcus
(n = 1), and
Alcaligenes faecalis
(n = 1). Three patients had negative cultures.
Cranial Neuropathies
Thirty-three percent of the
Pseudomonas
-infected patients
presented with facial nerve palsies, compared with none of
Table 1.
Pathogens and Clinical Features.
All Patients
Pseudomonas
MRSA
Other
Negative
Clinical Feature
(n = 20)
(n = 9)
(n = 3)
(n = 5)
(n = 3)
Percentage of patients
100
45
15
25
15
Average age (y)
64.9
62.3
63.0
65.0
74.3
Age range (y)
42-100
42-77
44-100
52-79
61-84
Diabetes mellitus
75%
100.0%
33.3%
80.0%
33.3%
Facial nerve palsy
25%
33.3%
0%
20%
33.3%
Bony erosion (on CT scan)
95%
100%
100%
100%
66.7%
Failed local treatment
80%
66.7%
100%
80%
100%
Definitive therapy (wk)
7.8
6.1
8.5
11.8
6.7
Total therapy (wk)
9.2
7.9
12.6
12.0
6.7
Abbreviations: CT, computed tomographic; MRSA, methicillin-resistant
Staphylococcus aureus
.
Hobson et al
84