ast reporting: how to get the biggest bang for your buck...aug 31, 2017 · provide advice on...

AST Reporting: How to get the

biggest bang for your buck: Clinically-orientated reporting, and

antimicrobial stewardship

Piotr Chlebicki

Senior Consultant

Department of Infectious Diseases

Singapore General Hospital

August 31, 2017

Microbiology Lab

Two main functions

1. Clinical – to help to diagnose and manage

infections in the individual patient

2. Epidemiological

Surveillance

Infection control

Outbreak management

Local antibiograms and guidelines

1. Clinical role

(not only diagnostic)

Advice how to collect the best specimen

(accept and reject specimens)

Advice how to transport

Advice which test to order

Advice on turnaround time

Helps to interpret it

Early notification for important results

Determine susceptibility

Provide advice on antibiotic choice

2. Epidemiological role of

microbiology lab

Surveillance

Infection control

Outbreak management

Local antibiograms and guidelines

Education

Organism specific HAI

surveillance

Identify ‘alert’ microorganisms

Methicillin-resistant Staphylococcus aureus

(MRSA)

Vancomycin-resistant enterococci (VRE)

MDR Pseudomonas aeruginosa

MDR Acinetobacter baumannii

MDR Mycobacterium tuberculosis

ESBL enterobacteria

Clostridium difficile

Another role is Antimicrobial

Stewardship

“prescribing antimicrobials only when they are

likely to be beneficial to the patient,

selecting agents that will target the likely

pathogens,

and using these agents at the correct dose

and for the proper duration”.

CDC Campaign

Why to do ASP?

Improve patients outcomes

Improve patients safety

Reduce resistance

Reduce cost

Or “optimize clinical outcomes while

minimizing unintended consequences”

How do clinicians prescribe antibiotics?

A. Based on culture results

B. Empirically = 7 steps

1. Define the problem/disease/syndrome

2. Severe?

3. At risk of MDRO?

4. Immunocompromized?

5. List possible organisms and consider local

resistance patterns

6. Pick the best antibiotic

7. Decide duration

How does microbiology lab can

influence ASP?

ASP = Appropriate Specimen Program

Rapid diagnostic tests

Selective reporting of susceptibility

Communication of critical results

Local epidemiology

Automatic alerts for targeted pathogens

Case 1

52 year old man, PMH of DM, complains of fever and

cough for 3 days. No recent hospitalization

120/70 HR 100, RR 25, 38.6 C

Crepitations over right lung base

Severity impacts diagnostic testing

Mild infection = testing optional

More severe infection = more testing

Outpatient CAP Hospitalized

CAP

Severe CAP

Testing optional Blood culture

Sputum Gram

stain and culture

Blood culture

Sputum Gram

stain and culture

Urinary antigen

(Legionella and

Streptococcus)

Molecular

testing

Interpreting sputum cultures (or any culture from non sterile site)

1. Does this patient really have infection for

which test was sent? (is it pneumonia?)

2. Was provided specimen of good quality?

3. Can isolated organism really cause this

infection?

1. Does this patient really have infection for

which test was sent? (is it pneumonia?)

52 year old man, PMH of DM, complains of fever and

cough for 3 days. No recent hospitalization

120/70 HR 100, RR 25, 38.6 C

?

Pneumonia most common and

most misdiagnosed

AJRCCM 2006

Methods

Randomized, controlled, open intervention

trial involving 302 patients with all severities

of CAP admitted to the emergency

department

procalcitonin group

“usual practice” (control group)

Patients with cystic fibrosis, PTB, HAP or

severely immunocompromised patients were

excluded

Antibiotic use was reduced but outcomes unchanged

Laboratory that offers biomarkers can have large impact

on antibiotic use

2. Was provided specimen of good quality?

Please reject

Specimen source: Respiratory

Specimen site: Sputum

Growth of

Klebsiella pneumoniae

Pseudomonas aeruginosa

Candida species

K. pn P. aer

Amox R

Aug S

Cefuroxime I

Ciprofloxacin S R

Ceftriaxone S R

Ceftazidime S S

Tri/Sulpha S

Pip/Tazo S S

Imipenem S S

Meropenem S S

Specimen source: Respiratory

Specimen site: Sputum

Epithelial cells: 2+

White cells: 1+

Mixed growth of Gram-negative bacilli

including

Klebsiella pneumoniae Scanty

growth

Comment:

Note presence of epithelial cells which

may indicate sample contamination

with upper airway flora.

Klebsiella is an uncommon cause of

community-acquired pneumonia.

Courtesy Dr Tan Thean Yen

Pretreatment Gram stain and culture of

expectorated sputum should be performed

only if a good-quality specimen can be

obtained and quality performance measures

for collection, transport, and processing of

samples can be met. (Moderate recommendation; level II evidence.)

Specimen source: Swab

Specimen site: Foot left, ulcer

Growth of

Klebsiella pneumoniae

Escherichia coli

Enterococcus faecium

K. pn E. coli E.

faecium

Amox R R S

Aug R R

Cefuroxime R R

Ciprofloxacin R R

Ceftriaxone R R

Tri/Sulpha S R

Pip/Tazo S S

Imipenem S S

Vancomycin R

Specimen source: Swab

Specimen site: Foot left, ulcer

Mixed growth of Gram-negative bacilli

and skin commensals

Comment:

Dependant sites are often colonised

with enteric bacteria. Gram-negative

bacilli usually represent superficial

colonisation or post-antibiotic flora,

rather than true infection.

REJECT

CDI Clinical Spectrum

Associated signs and symptoms: nausea, dehydration, low-grade fever, cramping and leukocytosis

Diarrhea

Colitis

Pseudomembranous

Colitis

Death

Toxic

Megacolon

Symptomless carriage

Severe case

Moderate

case

Asymptomatic

case


influence ASP?





Local epidemiology


Rapid diagnostic testing

Urinary streptococcal antigen

Gram stain

Rapid diagnostic testing for CAP

Urinary streptococcal antigen

Legionella urinary antigen

Respiratory virus multiplex PCR

Rapid Diagnosis

24 hour microbiology laboratories

“direct” susceptibility testing

rapid identification technologies Vitek automated systems MALDI-TOF fluorescent hybridisation PCR identification

Genexpert TB

Why not Genexpert MDRO??

Carba NP


influence ASP?





Local epidemiology


Susceptibility pattern of urinary E. coli

Antibiotic Susceptibility

Ampicillin R

Co-amoxiclav S

Cephalexin S

Cefuroxime S

Cefotaxime S

Ceftazidime S

Cefepime S

Cefoxitin S

Pip-tazobactam S

Meropenem S

Ciprofloxacin S

Nitrofurantoin S

Co-trimoxazole S

Amikacin S

Gentamicin S

Selective antimicrobial

susceptibility reporting

Susceptibilities are reported for only the most

appropriate and least expensive drugs to which the organism is susceptible.

The use of a cascading microbiology report encourages clinicians to select more narrow-spectrum and cost-effective antimicrobial agents.

Suppressing ciprofloxacin results

October 25, 2013 • SGH inpatients whose urine, wounds and respiratory specimens

grew Gram-negatives, and where is at least one more

susceptible antibiotic

• Still reported for all sterile sites

• Still released for outpatients, if it is the only susceptible oral

drug.

• Clinicians can call up the lab to ask for cipro results

Ciprofloxacin utilization (DDD per 100 inpatient days)

Ciprofloxacin use in SGH is empiric not culture based

Ertapenem in SGH is culture

directed

Attempt to spare meropenem


influence ASP?





Local epidemiology


Crucial communications


3 hospitals, 110 beds

Before and after design

189 patients (pre), 190 patients (post)

Intervention

Before

Cultures reported in the

system

Antibiotics changed by

physicians if and when

they notice the result

After

Automated alert sent to

ASP pharmacists

Pharmacist reviews

medical records

Pharmacist calls

physician, discusses case

and adjusts therapy

Results

Decreased time to appropriate therapy

(8 vs 14 hours)

Reduction in length of stay 2.2 days

Additionally, for patients who were not on

appropriate antimicrobial therapy at the time

of initial culture positivity benefit was even

stronger.

Not only reduction in LOS but also infection-

related mortality


influence ASP?





Local epidemiology


Local data 1. MRSA MIC

2012 in SGH

Of the 112 tested isolates, 58 had MIC of 1.5

or greater (51.8%)

Our lab in 2010

Summary and recommendation:

“… trough serum vancomycin concentrations of 15–20 mg/L are

recommended”.

Local data 2. Mupirocin and MRSA

Number of

Isolates

ST239 (%) ST22 (%) ST45 (%) Others (%) orfX (%) MupA (%)

A 157 8 (5.1%) 87 (55.4%) 13 (8.3%) 49 (31.2%) 2 (1.3%) 75 (47.8%)

B 31 1 (3.2%) 14 (45.2%) 3 (9.7%) 13 (41.9%) 0 (0%) 8 (25.8%)

C 10 1 (10.0%) 5 (50.0%) 1 (10.0%) 3 (30.0%) 0 (0%) 1 (10.0%)

D 44 2 (4.5%) 22 (50.0%) 11 (25.0%) 9 (20.5%) 0 (0%) 8 (18.2%)

E 76 3 (3.9%) 36 (47.4%) 9 (11.8%) 28 (36.8%) 2 (2.6%) 24 (31.6%)

SGH 159 22 (13.8%) 98 (61.6%) 5 (3.1%) 34 (21.4%) 15 (9.4%) 45 (28.3%)

F 188 18 (9.6%) 81 (43.1%) 23 (12.2%) 66 (35.1%) 11 (5.9%) 41 (25.8%)

Reducing use helps

Brazilian hospital

Mupirocin for every patient colonized or

infected with MRSA (including wounds)

They implemented a policy to restrict

mupirocin use to patients colonized but not

infected with MRSA

Resistance in clinical MRSA isolates fell from

65% to 15% over a period of five years

Vivoni et al, ICHE 2005;26:662-667

Results so far

Resistance rates fell below 20%

We are analyzing results

Antibiograms

How many isolates? Duplicates? Outpatient?

When last updated?

Impact on prescribing:

developing clinical pathways for empiric

antimicrobial treatment

monitoring resistance trends

updating the drug formulary

developing antimicrobial restriction policies

Antibiogram

Local data 3

Neutropenia protocol in Hematology.

Cefepime was the drug of choice for empiric

therapy

Is it really the drug of choice?

Antibiogram

But is piptazo effective against

ESBL?

But is piptazo effective against ESBL? CGH data, ESBL E coli, 2012

Local data 3

Febrile neutropenia protocol was changed

from cefepime alone to piperacillin-

tazobactam or cefepime plus amikacin


influence ASP?





Local epidemiology


MRSA and VRE alert

Summary

The impact of microbiology lab on prescribers

is profound

It not only influence the choice of antibiotics

for individual patients but also hospital

policies and guidelines

ast reporting: how to get the biggest bang for your buck...aug 31, 2017 · provide advice on...

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