2
0
1
3
CASES
(with answers!)
Update on the CLSI Standards for
Antimicrobial Susceptibility Testing:
What’s New with the
Gram Positive Organisms?
Susan E. Sharp, Ph.D., DABMM, FAAM
Director - Regional and Sunnyside Medical Center Laboratories
Director - Regional Clinical Microbiology
Kaiser Permanente
Associate Professor - Department of Pathology
Oregon Health & Sciences University
Portland, OR
Case 1
 32 year old pregnant woman had a vaginal-rectal specimen
sent for GBS culture.
 The culture was positive and results were sent to the doctor.
 Two days later the doctor’s office calls and requests
suceptibility testing because the patient is very allergic to
penicillin and the doctor needs the results for a non lactam antibiotic for this patient.
 You subculture the isolate for susceptibility testing.
2
Case 1
 When testing GBS from a prenatal screen culture, the most
important drugs to test and report are?
 Drugs to Test (and why):
 Drugs to Report (and why):
3
4
5
6
CDC Guidelines
Case 1
** If an isolate is resistant to erythromycin, it might have inducible resistance to clindamycin, even if it appears susceptible to
clindamycin. If a GBS isolate is susceptible to clindamycin, resistant to erythromycin, and testing for inducible clindamycin resistance
is negative, then clindamycin can be used for GBS intrapartum prophylaxis instead of vancomycin.
7
Case 1: Group B Streptococcus
Intrapartum prophylaxis
CLSI M100-S23. Table 1B.
Rx: Recommendations for intrapartum prophylaxis for Group B streptococci
are penicillin or ampicillin. Although cefazolin is recommended for
penicillin-allergic women at low risk for anaphylaxis, those at high risk for
anaphylaxis may receive clindamycin. Group B streptococci are
susceptible to ampicillin, penicillin, and cefazolin, but may be resistant to
erythromycin and clindamycin. When a Group B Streptococcus is
isolated from a pregnant woman with severe penicillin allergy (high risk
for anaphylaxis), erythromycin and clindamycin (including inducible
clindamycin resistance) should be tested, and only clindamycin should
be reported. (see Table 2H-1 Supplemental Table 1.)
8
Case 2: Specimen: Wound drainage
Diagnosis: Trauma - Staphylococcus aureus
MIC ( g/ml)
clindamycin
erythromycin
oxacillin
penicillin
vancomycin
≤0.5 - S
≤0.5 - S
≤0.5 - S
R
≤0.5 - S
Patient is receiving piperacillin-tazobactam for nosocomial
pneumonia. The physician asks that piperacillin-tazobactam
be tested on this S. aureus ? What do you tell them and why?
9
Case 2: Staphylococcus spp.
M100-S22. Table 2C.
2013 - Eliminated breakpoints fo
Penicillins
BL/BL inhibitor combos
Cephalosporins
Carbapenems
Case 2: Staphylococcus spp.
β-Lactam Breakpoints Remaining
 Penicillin
– Represents penicillinase-labile penicillins
 Oxacillin
– Represents penicillinase-stable penicillins
 Cefoxitin
– Surrogate for oxacillin
 Ceftaroline (added 2013)
– Cephalosporin with anti-MRSA activity
Case 2: Staphylococcus spp.
Penicillins and Penicillinases
Penicillinase-labile
Penicillins
Amoxicillin
Ampicillin
Carbenicillin
Mezlocillin
Penicillin
Piperacillin
Ticarcillin
12
Penicillinase-stable
Penicillins
Cloxacillin
Dicloxacillin
Flucloxacillin
Methicillin
Nafcillin
Oxacillin
Case 2: Staphylococcus spp. - β-Lactams
Use Pen and Ox results to predict results for other ß-lactams
Test Results
Oxacillin
Penicillin
(cefoxitin)
S
S
R
S
R
R
Predicts
Susceptible to:
All penicillins
ß-lac / ß-lactamase inhibitor combos
Cephems
Carbapenems
Resistant to:
Penicillinase-labile penicillins
Susceptible to:
Penicillinase-stable penicillins
ß-lac / ß-lactamase inhibitor combos
Cephems
Carbapenems
Resistant to:
All ß-lactams (except cephems with antiMRSA activity, e.g., ceftaroline)
Case 2: Specimen: Wound drainage
Diagnosis: Trauma - Staphylococcus aureus
MIC ( g/ml)
clindamycin
erythromycin
oxacillin
penicillin
vancomycin
≤0.5 - S
≤0.5 - S
≤0.5 - S*
R
≤0.5 - S
*Oxacillin-S staphylococci are susceptible to pip/tazobactam.
14
Case 2a: Specimen: Wound drainage
Diagnosis: Trauma - Staphylococcus aureus
MIC ( g/ml)
clindamycin
erythromycin
oxacillin
penicillin
vancomycin
>8.0 - R
>8.0 - R
>16 - R
R
≤0.5 - S
Clinician calls; serious infection, can’t use vanco in this patient, needs other
drug choices. What do you tell them, what do you do, and why?
15
Case 2a: Specimen: Wound drainage
Diagnosis: Trauma - Staphylococcus aureus
ceftaroline
clindamycin
daptomycin
doxycycline*
erythromycin
linezolid
oxacillin
penicillin
rifampin*
SXT*
vancomycin
MIC ( g/ml)
0.5
>4
0.5
≤1
>4
1
>8
≤0.5
≤0.5/9.5
2
S
R
S
S
R
S
R
R
S
S
S
Possible Chart comment:
MRSA are resistant to all β-lactam agents except ceftaroline.
*Doxycycline, rifampin or SXT should not be used alone for serious
MRSA infections.
16
Case 2a: Ceftaroline
 Broad-spectrum cephalosporin (with anti-MRSA activity)
 IV only
 FDA clinical indications
– Acute bacterial skin and skin structure infections, communityacquired bacterial pneumonia
 Activity spectrum:
– GPC (staphylococci including MRSA; β-hemolytic streptococci;
S.pneumoniae)
– Enterobacteriaceae
 Not - ESBL, ampC, or carbapenemase producers
– H.influenzae
– Not - Pseudomonas aeruginosa
17
Case 3
 You want to change from your current staphylococci disk
diffusion susceptibility panel to a new panel on your
automated AST system.
– What is your current process?
– What will be your process in 2014?
18
Case 3
 Prior to adding a new AST panel …
– Must perform “verification’ according to CLIA 493.1253
– Testing ATCC QC strains alone is insufficient for ‘verification’
testing (per CLSI and CLIA)
Ref: Cumitech 31A: Verification/Validation of Procedures in the
Clinical Microbiology Laboratory. (ASM Press)
19
Case 3
 Verification &
Validation
20
Case 3
 You want to change from your current staphylococci disk
diffusion susceptibility panel to a new panel on your
automated AST system.
– What is your current process?
– What will be your process in 2014?
21
22
Verification
Validation
The documentation of either commercial
or laboratory-developed test
performance. For FDA cleared or
approved tests, it is the process of
examination or evaluation of a test
system to determine whether the claims
stipulated by the manufacturer in the
package insert as they relate to the
product, the process, the results, or the
interpretation can be achieved.
Verification requires determination or
confirmation of the test performance
characteristics, including sensitivity,
specificity, and, where appropriate, the
predictive values, precision, and
accuracy of the test. Verification is a onetime process, completed before the test
or system is used for patient testing. See
Appendix A. Method selection and
verification example.
The documentation that a test which has
already been verified is repeatedly giving
the expected results as the test is
performed over a period of time.
Validation confirms that the test continues
to perform satisfactorily according to the
laboratory’s requirements or the
manufacturer’s claims or, for laboratorydeveloped tests, according to its intended
use. The requirements for test validation
may include personnel competency
assessment, quality control, internal and
external proficiency testing, and
correlation with clinical findings.
Validation thus becomes an integral part
of the laboratory’s quality assurance
program.
Verification Testing
CAP Phase II
COM.10600 Manufacturer Instructions
For FDA approved/cleared tests, the laboratory follows manufacturer
instructions or provides documentation of validation study(ies) if the test has
been modified.
NOTE: For example, the laboratory must verify established performance
specifications of FDA approved assays (accuracy, precision, analytic sensitivity,
interferences, reference range and reportable range, as applicable).
If the laboratory modifies manufacturer instructions, the test is categorized as a
non-FDA approved/cleared test, and the modification mush be validated by the
laboratory. A change in the specimen type of collection device is considered a
modification.
23
Case 3
 Perform appropriate QC strain(s) for either:
– 20-30 day QC plan
– 3x5 (15 replicate) QC plan
 Test a min. of 30 representative isolates from your institution
on the new automated AST panel
 Test these 30 isolates also by a reference method (disk
diffusion, frozen MIC panel), send to a reference lab, or use
organisms with known results.
24
Case 3 - NEW AST QC: 3x5 (15) Plan - 2013
 An alternate QC plan using a two-phase, 15 replicate (3 X 5 day) plan
is described in Table 3C as follows:
– 15 replicate (3 X 5 day) plan
 Test three replicates using individual inocula preparations of the
appropriate QC strains for 5 consecutive test days to perform the 15
replicate (3 x 5 day) plan.
 Each QC strain tested is evaluated separately according to the acceptance
criteria and recommended action described below (e.g., pass, test another
3 replicates for 5 days, fail).
 Upon successful completion of the QC plan, the laboratory can convert
from daily to weekly QC testing.
 If unsuccessful investigate, take corrective action as appropriate and
continue daily QC testing.
25
Case 3 - NEW AST QC 3x5 (15) - 2013
Table 3C*
Number out of range
with initial testing
(based on 15
replicates)
0-1
2-3
4 or greater
26
Conclusion from
initial testing
QC plan successful.
Convert to weekly QC
testing.
Test another 3
replicates for 5 days.
QC plan fails.
Investigate and take
corrective action as
appropriate. Continue
QC each test day.
*Assess each QC strain individually
Number out of range
after repeat testing
(based on all 30
replicates)
Conclusion after
repeat testing
NA
NA
2-3
QC plan successful.
Can convert to weekly
testing.
4 or greater
QC plan fails.
Investigate and take
corrective action as
appropriate. Continue
QC each test day.
Case 3 - NEW AST QC 3x5 (15) - 2013
Test 3 replicated of each QC
strain for 5 days using individually
prepared inoculum
0-1 of 15 out
of range?
Pass. Convert
to weekly QC.
2-3 of 15 out
of range?
Test another 3
replicates for 5
days
2-3 of 30 out
of range?
27
> 4 of 15 out
of range?
Pass. Convert
to weekly
QC.
> 4 of 30 out
of range?
Fail.
Continue to
include QC
each test
day. Take
corrective
action.
Case 3 – Rest of verification testing…
Acceptance rate per CUMITECH

< 10% combination of major errors (S/R) and minor
errors (S/I; I/R)

With no more than 5% major errors

Overall EA & CA of > 90%


28
Essential Agreement: Agreement within +1 twofold dilution of
the drug as compared to the reference method
Categorical Agreement: Both are S, or I, or R
Case 3: EXAMPLE - 1

Biapenem: 20 isolates (<1; 2; >4)
Reference method results
MSSA
(20)
0.12
0.12
9
0.25
NEW panel
results
0.5
0.25
0.5
1.0
2.0
S
8
I
4.0
R
1a
1.0
2.0
1
1a,b
4.0
8.0
29
Major errors: 0%
Minor errors: 5% (b)
EA: 90% (a,b - 2/20)
CA: 95% (b - 1/20)
8.0
Case 3: EXAMPLE - 1
1) < 10% combination of major & minor errors
(With no more than 5% major errors)
2) Overall EA & CA of > 90%
Our example:
Major errors: 0% (0) EA: 90% (2)
Minor errors: 5% (1) CA: 95% (1)
30
Case 3: EXAMPLE - 1
1) < 10% combination of major & minor errors
(With no more than 5% major errors)
2) Overall EA & CA of > 90%
Our example:
Major errors: 0% (0) EA: 90% (2)
Minor errors: 5% (1) CA: 95% (1)
31
Case 3: EXAMPLE - 2

Biapenem: 20 isolates (<1; 2; >4)
Reference method results
MSSA
(20)
0.12
0.12
11
0.25
0.25
NEW panel
results
0.5
0.5
1.0
S
2
1
1.0
2.0
4.0
2.0
I
4.0
8.0
R
1
1
1
1
1
1
8.0
Major errors: ? %
Minor errors: ? %
EA: ? %
CA: ? %
32
Case 3: EXAMPLE - 2

Biapenem: 20 isolates (<1; 2; >4)
Reference method results
MSSA
(20)
0.12
0.12
11
0.25
NEW panel
results
0.5
1.0
0.25
0.5
1.0
S
2
1a
2.0
I
4.0
R
1
1b
2.0
4.0
1
1
1c
1d
8.0
33
Major errors: 5% (d)
Minor errors: 5% (c)
EA: 80% (4/20 – a,b,c,d )
CA: 90% (2/20) – c,d
8.0
Case 3: EXAMPLE - 2
1) < 10% combination of major & minor errors
(With no more than 5% major errors)
2) Overall EA & CA of > 90%
Our example:
Major errors: 5% (1) EA: 80% (4)
Minor errors: 5% (1) CA: 90% (2)
34
Case 3: EXAMPLE - 2
1) < 10% combination of major & minor errors
(With no more than 5% major errors)
2) Overall EA & CA of > 90%
Our example:
Major errors: 5% (1) EA: 80% (4)
Minor errors: 5% (1) CA: 90% (2)
35
Case 3: EXAMPLE - 2
– Accuracy of the new or revised test does not satisfy the
verification requirements
 Withdraw the test for consideration, or
 Corrective action must be taken by the user &/or the
manufacturer
 After corrective action, verification must again take
place
36
Case 4
 SPECIMEN: Blood culture
 DIAGNOSIS: Endocarditis
 ORGANISM: Staphylococcus aureus
MIC ( g/ml)
37
clindamycin
8 “R”
erythromycin
16 “R”
oxacillin
< 0.5 “S”
vancomycin
< 0.5 “S”
Case 4
 SPECIMEN: Blood culture
 DIAGNOSIS: Endocarditis
 ORGANISM: Staphylococcus aureus
MIC ( g/ml)
38
clindamycin
8 “R”
erythromycin
16 “R”
oxacillin
< 0.5 “S”
vancomycin
< 0.5 “S”
Physician calls
with
an additional
request…
Case 4
 The physician would like to treat this patient with penicillin
as it will be a long and protracted course of therapy for this
patient.
 They notice that penicillin was not resulted on the patient’s
report.
 What do you tell the physician about the penicillin result on
this patient’s isolate?
 What further steps do you take regarding this request?
39
Case 4: Staphylococcus aureus
Penicillin (MIC ≤0.12 µg/ml) Reporting
Note: If doing disk
diffusion routinely,
just examine zone
edge for those with
zone sizes of >
29mm.
Penicillin MIC ≤0.12 µg/ml
A
B
Nitrocefin β-lactamase
positive
Report penicillin “R”
A
Nitrocefin βlactamase negative
Perform penicillin disk zone-edge test
≥ 29 mm fuzzy
Report penicillin “S”
40
M100-S22.
Table 2C Supplemental Table 1. Page 80
≥ 29 mm sharp
Report penicillin “R”
Case 4: Staphylococcus aureus
Disk Zone Edge Test (10 U penicillin disk and standard DD method)
Fuzzy / “beach” =
β-lactamase negative,
Penicillin - S
Sharp / “cliff” =
β-lactamase positive,
Penicillin - R
41
Reference:
M100-S22. Table 2C Supplemental Table 1. Page 83
S. aureus
supplemental QC:
Neg - ATCC 25923
Pos - ATCC 29213
Case 4
 This is an appropriate request for endocarditis.
 Test penicillin by an MIC or DD method to penicillin.
 If pen = R (>0.25 g/ml / <28mm); done = Report “R”
 If pen = S (<0.25 g/ml / > 28mm) 
– Perform -lactamase test:
 If +; done = Report “R”
 If -;  DD for beach/cliff
– Beach; Report penicillin “S” (- -lactamase production)
– Cliff;
42
Report penicillin “R” (+ -lactamase production)
Case 5
25 y/o woman with acute cystitis.
 UR culture grows >100,000 Staphylococcus species
 The physician wants additional identification and AST done.
What is the most likely species of this organism?
Do you perform any additional laboratory tests?
What do you tell the physician?
43
Case 5
25 y/o woman with acute cystitis.
 UR culture grows >100,000 cfu/ml Staphylococcus species
– S.saprophyticus most likely agent in young sexually active
women
44
Case 5
Organism
/
Drug
Novobiocin
Fosfomycin
Fusidic Acid
S.aureus/S.lugdunensis
There is no intrinsic resistance in these species.
S.epidermidis
There is no intrinsic resistance in this species.
S.haemolyticus
There is no intrinsic resistance in this species.
S.saprophyticus
R
S.capitis
R
S.cohnii
R
S.xylosus
R
45 January 8, 2014
R
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
R
Case 5
25 y/o woman with acute cystitis.
 UR culture grows >100,000 cfu/ml Staphylococcus saprophyticus
 The physician wants additional identification and AST done.
CLSI 2012; Table 2C, General comment #6
“Routine testing of urine isolates of S.saprophyticus is not advised,
because infections respond to concentrations achieved in urine of
antibimcrobial agents commonly used to treat acute, uncomplicated
urinary tract infections (eg., nitrofurantoin, trimethoprim +/sulfamethoxazole, or a fluoroquinolone).”
46
Case 6
 Young boy 3 y/o presents with pneumonia.
 The suctioned sputum grows out the pathogen:
Streptococcus pneumoniae.
 You do AST and get the following results :
– Erythromycin-R, Penicillin-R, Ceftriaxone-S, SXT-R, Levofloxacin-S
 Doc wants to use clindamycin for this patient.
 What and how do you test, and how do you report the
susceptibility results?
47
Case 6
 S.pneumoniae & inducible CLI-R:
– The clinical significance of this mechanism of clindamycin
resistance is not known for S.pneumoniae, but inducible
clindamycin resistance can be detected using D-zone testing and
is now included in the 2013 CLSI documents.
 “If testing S.pneumoniae to clindamycin and the isolate is
clindamycin-S, a test for inducible clindamycin resistance should be
performed.”
– 12mm for spacing of disks for disk diffusion testing
– 1 g/ml Ery + 0.5 g/ml Clinda for broth microdilution testing
48
Case 7
 Patient develops pain and swelling in the abdomen.
 Ascetic fluid is collected and sent for culture.
 The specimen Gram stain 
– Many PMNs
– Moderate GPC in chains resembling streptococci
 The culture grows a pure culture of many
Streptococcus anginosus group.
49
Case 7
You report out your normal AST of the following for this organism:
– pencillin (R), ceftriaxone (S), vancomycin (S), clindamycin (S),
erythromycin (S)
 The physician calls and asks for azithromycin to be tested. You
do have azithromycin disks. What do you do?
 The physician calls and asks for doripenem to be tested. You do
have doripenem disks and it is also in your streptococci broth
microtiter panels. What do you do?
50
Case 7
The physician calls and asks for azithromycin to be tested. You do have
azithromycin disks. What do you do?
 Table 1B: (page 39 M100-S23) Footnote a 
– Susceptibility and resistance to azithromycin, clarithromycin, and
dirithomycin can be predicted by testing erythromycin.
 Tell the doctor that based on the erythromycin susceptible result
azithromycin will be S and testing is not necessary.
51 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
Case 7 Doripenem
The physician calls and asks for doripenem to be tested. What do you do?
Complicated Intra-Abdominal Infections
 Indicated as a single agent for the treatment of complicated intra-abdominal infections
caused by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa,
Bacteroides caccae, Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides
uniformis, Bacteroides vulgatus, Streptococcus intermedius, Streptococcus
constellatus and Peptostreptococcus micros.
Complicated Urinary Tract Infections, Including Pyelonephritis
 Indicated as a single agent for the treatment of complicated urinary tract infections,
including pyelonephritis caused by Escherichia coli including cases with concurrent
bacteremia, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and
Acinetobacter baumannii.
52
Case 7
 Doripenem
– No CLSI disk diffusion breakpoints; only MIC
breakpoints
– You test by appropriate MIC method
 Result is 2 g/ml
 What do you do?
53
Case 7 Doripenem (Gram positive’s)
(No disk diffusion criteria)
Streptococcus Viridans group (O)
-Streptococcus (O)
S.pneumoniae (O)
S.aureus*
S ( g/ml)
I ( g/ml)
R ( g/ml)
< 1.0
-
-
< 0.12
-
-
< 1.0
-
-
-
-
-
– For some organism/antimicrobial agent combinations, the absence or rare
occurrence of resistant strains precluded designing any result categories other
than “susceptible”.
– For strains yielding results suggestive of a ‘nonsusceptible’ category, organism
identification and antimicrobial susceptibility test results should be confirmed.
54
*Remember:
Only penicillin, oxacillin [cefoxitin], ceftaroline for staph with the -lactams in 2013.
Case 7
 Doripenem
– No CLSI disk diffusion breakpoints; only MIC
breakpoints
– You test by appropriate MIC method
 Result is 2 g/ml
 What do you do? 
– Repeat ID and AST, if all ok 
– Report as “Non-susceptible”
55
Case 8
 An E.coli is isolated from a osteomyelitis (bone) specimen and has
the following AST:
MIC g/ml
– Ampicillin
64
R
– Cefazolin
16
R
– Ceftriaxone
8
R
– Ceftazidime
8
I
– Cefepime
8
?
– Gentamicin
1
S
– SXT
1/19
S
– Ciprofloxacin
0.5
S
56 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
Case 8
Cefepime MIC = 8 g/ml
 How would you report the interpretive criteria today?
 How will you report the interpretive criteria in January, 2014?
57 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
Case 8 “S-DD”
Enterobacteriaceae and cefepime
ISSUE: When the cephalosporin breakpoints to the Enterobacteriaceae were change
(lowered) in 2010, cefepime was also reviewed but the committee at that time
left the breakpoint unchanged at < 8 / 16 / > 32 ug/ml.
RESULT: The committee voted to change cefepime breakpoints for the
Enterobacteriaceae from current to the below:
S < 2 ug/ml
SDD 4-8 ug/ml (SDD = susceptible, dose-dependent)
R > 16 ug/ml
58 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
Case 8 “S-DD”
 In January, your physician calls and wants to know what the heck
SDD is ??
59 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
Case 8 “S-DD”
Enterobacteriaceae and cefepime
 ‘SDD’ indicates that approved, higher therapeutic levels of this drug can be
used to treat serious infections with organisms having an MIC in this range.
– “SDD indicates that this drug may be used in high doses to achieve the
maximum achievable drug doses”.
– Rx Comment
 “The SDD breakpoint was derived based on a dosage regimens of 1
g Q 8 hr or 2 g Q 12 hr for organisms with a MIC of 4 ug/ml, and 2 g
Q 8 hr for those with a MIC of 8 ug/ml.”
60 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
Case 8
 E.coli from Osteomyelitis (bone) specimen has the following AST:
MIC g/ml
– Ampicillin
64
R
– Cefazolin
16
R
– Ceftriaxone
8
R
– Ceftazidime
8
I
– Cefepime
8
SDD*
– Gentamicin
1
S
– SXT
1/19
S
– Ciprofloxacin
0.5
S
*Possible Chart Comment: “SDD = susceptible dose dependent; dosage regimens of 1g Q 8 hr or 2g Q 12 hr for
organisms with MICs of 4 ug/ml, and 2g Q 8 hr for those with MICs of 8 ug/ml.”
61 January 8, 2014
|
© 2011 Kaiser Foundation Health Plan, Inc. For internal use only.
QC #1
 “Previously, Antibiotic A was not on our routine test panel. When we
were asked to test Antibiotic A on a patient’s isolate, we tested the
patient’s isolate and performed QC testing for Antibiotic A on the
same day. Now we want to begin testing Antibiotic A routinely. Can
we use the last 20 consecutive QC results to justify conversion from
daily to weekly QC testing of Antibiotic A? Only one QC result for
antibiotic A was out of control during the past 20 days on which we
tested Antibiotic A and this corrected upon repeat testing.”
– What is your current process?
– What will be your process in 2014?
62
QC #1: Implementing Weekly QC
 OLD: Test 20-30 consecutive day QC: < 1/20 or < 3/30 acceptable.
 NEW: 3x15 QC plan
Number out of range
with initial testing
(based on 15
replicates)
0-1
2-3
4 or greater
63
Conclusion from initial
testing
QC plan successful.
Convert to weekly QC
testing.
Test another 3
replicates for 5 days.
QC plan fails.
Investigate and take
corrective action as
appropriate. Continue
QC each test day.
Number out of range
after repeat testing
(based on all 30
replicates)
Conclusion after repeat
testing
NA
NA
2-3
QC plan successful.
Can convert to weekly
testing.
4 or greater
QC plan fails.
Investigate and take
corrective action as
appropriate. Continue
QC each test day.
QC #1: Implementing Weekly QC
New for 2014 (we hope!)
 Review old records:
 Acceptable if you have been performing QC testing of a
drug each time you test a patient’s organism, you will be
able to use that contemporary (within the last year)
retrospective data in order to collect data that can be
used for going to weekly QC testing.
 For example, if you have QC tested a drug approximately
2x/month for the last year, you can use the most recent 20
QC tests to document your ability to go to weekly QC testing
for the drug.
64
QC #2
 ”I am seeking assistance regarding the following; our laboratory was
recently cited during a CAP inspection for not following the CLSI
guidelines regarding an unacceptable MIC value for one drug per one
QC organism per one instance with weekly QC done for the month of
March. Repeat testing on said organism was okay the following day.
(Please keep in mind, although we could not define an obvious error,
this was only one instance for one drug on one QC organism; aside
from this exception, our weekly controls are typically within expected
ranges).”
– What is your current process?
– What will be your process in 2014?
65
QC #2
 OLD = If no clear reason can be found for the error, then repeat testing for
5 days; if all in-range, acceptable to return to weekly testing; if > 1
result(s) are out of range, return to 20-30 day testing scheme.
 NEW = If the 4 previous QC results were acceptable (same lot #s of
materials) and you obtain an out-of-range result, repeat the QC as soon
as possible; if this repeat is within range, the corrective action is
successful and you can resume weekly testing.
– If the repeat is out-of-range  you must take additional corrective action, and daily
QC tests must be continued until final resolution of the problem is achieved.
– If 4 previous QC results were not acceptable or not available or were not tested with
the same lot #s of materials  test sufficient QC replicates to satisfy the
requirement for a total of 5 acceptable results (up to 3 QC replicates can be tested in
a single day if individual inoculum preparations are used).
66
QC #3
Here is your current QC sheet for weekly QC of the disk
diffusion you use for testing isolates of P.aeruginosa
PSA QC
E.coli
(ATCC
25922)
PSA
(ATCC
27853)
E.Coli
(ATCC
35218)
Test
date
Tester
initials
QC
OK? y/n
Pip/Tazo
25
30
28
1/13/13
SS
Y
Ceftazidime
30
25
1/13/13
SS
Y
Gentamicin
22
20
1/13/13
SS
Y
Ciprofloxacin
37
27
1/13/13
SS
Y
Meropenem
31
31
1/13/13
SS
Y
Cefepime
32
27
1/13/13
SS
Y
Tobramycin
21
22
1/13/13
SS
Y
67
QC #3
Here is your current QC sheet for weekly QC of the disk
diffusion you use for testing isolates of P.aeruginosa
PSA QC
E.coli
(ATCC
25922)
PSA
(ATCC
27853)
E.Coli
(ATCC
35218)
Test
date
Tester
initials
QC
OK? y/n
Pip/Tazo
25
30
28
1/13/13
SS
Y
Ceftazidime
30
25
1/13/13
SS
Y
Gentamicin
22
20
1/13/13
SS
Y
Ciprofloxacin
37
27
1/13/13
SS
Y
Meropenem
31
31
1/13/13
SS
Y
Cefepime
32
27
1/13/13
SS
Y
Tobramycin
21
22
1/13/13
SS
Y
68
QC #3
Here is your EDITED QC sheet for weekly QC of the disk
diffusion you use for testing isolates of P.aeruginosa
PSA QC
E.coli
(ATCC
25922)
PSA
(ATCC
27853)
E.Coli
(ATCC
35218)
Test
date
Tester
initials
QC
OK?
Y/N
Pip/Tazo
25
30
28
1/13/13
SS
Y
Ceftazidime
30
25
1/13/13
SS
Y
Gentamicin
22
20
1/13/13
SS
Y
Ciprofloxacin
37
27
1/13/13
SS
Y
Meropenem
31
31
1/13/13
SS
Y
Cefepime
32
27
1/13/13
SS
Y
Tobramycin
21
22
1/13/13
SS
Y
69
QC #3
Here is your NEW QC sheet for weekly QC of the disk
diffusion you use for testing isolates of P.aeruginosa
70
PSA QC
PSA
(ATCC
27853)
E.Coli
(ATCC
35218)
Test
date
Tester
initials
QC
OK? y/n
Pip/Tazo
30
28
1/13/13
SS
Y
Ceftazidime
25
1/13/13
SS
Y
Gentamicin
20
1/13/13
SS
Y
Ciprofloxacin
27
1/13/13
SS
Y
Meropenem
31
1/13/13
SS
Y
Cefepime
27
1/13/13
SS
Y
Tobramycin
22
1/13/13
SS
Y
71