|
#
|
S. aureusisolate
|
β-lactamase genotype*&(‘blaZ’PCR)
|
β-lactamase phenotype by nitrocefin disk test
|
|---|
|
1
|
29213
|
Positive
|
+
|
|
2
|
25923
|
Negative
|
-
|
|
3
|
75391-09
|
Positive
|
-
|
|
4
|
W5337
|
Negative
|
-
|
|
5
|
W53156
|
Positive
|
-
|
|
6
|
AI5070237
|
Positive
|
+
|
|
7
|
AI5081845
|
Positive
|
-
|
|
8
|
159570-08
|
Positive
|
-
|
|
9
|
H30876
|
Positive
|
-
|
|
10
|
32455-09
|
Positive$
|
-
|
|
11
|
HIP12052
|
Positive
|
-
|
|
12
|
AI5090298
|
Positive
|
-
|
|
13
|
F33263-2
|
Positive
|
-
|
|
14
|
AI5090297
|
Positive
|
-
|
|
15
|
HIP11033
|
Positive
|
-
|
|
16
|
HIP11353
|
Positive$
|
-
|
|
17
|
158390-08
|
Positive$
|
-
|
|
18
|
F52670
|
Positive
|
+
|
|
19
|
H63189
|
Positive
|
+
|
|
20
|
M24125
|
Positive
|
+
|
|
21
|
F20358.1
|
Negative
|
-
|
|
22
|
H67147.3
|
Positive
|
-
|
|
23
|
M60028
|
Negative
|
-
|
|
24
|
KI58249.2
|
Unknown
|
-
|
|
25
|
M69678
|
Negative
|
-
|
|
26
|
X33116
|
Positive
|
-
|
|
27
|
F29916-2
|
Positive
|
-
|
-
S. aureus strains 29213 (#1) and 25923 (#2) were obtained from ATCC and the S. aureus clinical isolates (#3 - #27) were provided by Dr. Mary Jane Ferraro (Microbiology Labs, Massachusetts General Hospital, Boston, MA, USA). Isolate numbers (e.g. #1 for 29213, etc) are used to refer to the different isolates throughout the study.
- *The β-lactamase genotype was determined by PCR to detect blaZ (staphylococcal β-lactamase gene). Genotype data for isolates #3 - #15 was kindly provided by Dr. Robert L. Skov, Statens Serum Institut (R. L. Skov, unpublished results) and for #16 - #27 by Dr. Mary Jane Ferraro.
-
&All isolates are MSSA.
-
$Special comment – blaZ contained Stop codon or deletion (so non-functional) (R. L. Skov, unpublished results).
- Nitrocefin disk test to determine β-lactamase production was performed as described in Methods. Development of orange colour uniformly, similar to positive control #1, was taken as positive reaction, indicated by ‘+’ symbols. ‘-’ denotes negative result (i.e. no colour change). The results are representative of three independent experiments, which gave consistent results.
