CHANGES IN CLSI 2017

Capt. Mohammed Ashraf Ali M.D (Microbiology)

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OUTLINE

A. Definition of Test / Report groupsB. Major deletions in CLSI 2017C. Summary of antibiotic changes for

Individual bacteria D. Addition of Supplemental testsE. Changes in reporting for colistin

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A. ANTIBIOTIC TEST/REPORT GROUPS

Group A: Routine reporting against specific organism

Group B: Warrants primary testing and selective reporting.

Group C: Supplemental antimicrobial agents: institutional

endemic/epidemic resistant strains

Group U (“urine”): antimicrobials for treating UTIs.

Group O (“other”): clinical indication but are generally not

candidates for routine testing and reporting.

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Table 1A- Antimicrobial Agents :Testing and Reporting on Nonfastidious Organisms.

Table 1B – Fastidious organisms

Table 1C - Anaerobic Organisms

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Moved to Test

Group C

No changes

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Deleted

Deleted

Deleted

Deleted

No changes

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TABLE – 1A (cont…)

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Deleted

TABLE – 1A

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TABLE – 1B

Deleted

Deleted

Ciprofloxacin orlevofloxacin ormoxifloxacin

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TABLE – 1B (cont..)

Deleted

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B. MAJOR DELETIONS

1. Norfloxacin – Group U drug : Table 1A2. Cefuroxime (parenteral) and gemifloxacin

from Table 1A, 1B and 1C.3. Nalidixic acid breakpoints for Salmonella

spp4. Telavancin disk diffusion breakpoints for

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ORGANISMS IN TABLE 1AStaphylococcus spp and Enterococcus spp. : Norfloxacin – deleted Moved ortivancin and telavancin to Test Group C

Enterobacteriaceae (except Salmonella sp) : Gemifloxacin, norfloxacin – deleted Enoxacin – moved to Test Group C Nalidixic acid – Moved to Test group O

(Enterobacteriaceae except Salmonella)

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Salmonella spp. Nalidixic acid disc diffusion breakpoints deleted for

Salmonella spp. Preferred test for assessing fluoroquinolone

susceptibility or resistance is a ciprofloxacin MIC test Pefloxacin disk diffusion test – surrogate test to predict

ciprofloxacin susceptibility

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Epidemiological Cutoff Values (ECVs) for Enterobacteriaceae not to be used as clinical breakpoints

Antimicrobial agent

MIC ECV Comments

WT NWT

Colistin ≤ 2 ≥ 4 For use with E. aerogenes, E. cloacae, E.coli, K. pneumoniae and R. ornitholytica

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Pseudomonas aeruginosa Deleted colistin disk diffusion breakpoints. Deleted polymyxin B disk diffusion breakpoints. Moved norfloxacin to Test/Report group O and clarified

reporting. Revised colistin MIC breakpoints.

Acinetobacter spp No changes

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Other Non-Enterobacteriaceae Deleted colistin and polymyxin B. Deleted urinary tract infection (UTI) restriction for

gatifloxacin, lomefloxacin and ofloxacin.

Staphylococcus spp :

No changes

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ORGANISMS IN TABLE 1BH.Influenzae and H.parainfluenzae : Moved ciprofloxacin, levofloxacin and moxifloxacin to

Test Group B. Moved trimethoprim-sulfamethoxazole to Test Group C. Moved cefuroxime (parenteral) to Test Group C. Moved gemifloxacin to Test Group C.

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Epidemiological Cutoff Values (ECVs) for Neisseria gonorrhoeae :

Antimicrobial agent

MIC ECV Comments

WT NWT

Azithromycin ≤ 1 ≥ 2 For use with N.gonorrhoeae

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ORGANISMS IN TABLE 1CEpidemiological Cutoff Values (ECVs) for Propionibacterium acnes

Antimicrobial agent

MIC ECV Comments

WT NWT

Vancomycin ≤ 2 ≥ 4 For use with P.acnes

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4. Changes in reporting for Colistin

Colistin, Polymyxin B not to be reported in Non-Enterobacteriaceae

In P.aeruginosa, Colistin and PB not to be reported by disc diffusion. Revised colistin MIC breakpoints

LIPOPEPTIDESS I R

Colistin (10µg) ≤ 2 --- ≥ 4

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E. ADDITIONAL TESTSmodified carbapenem inactivation method (mCIM) for suspected carbapenemase production : Enterobacteriaceae only

Test mCIM

When to do? For epidemiological, not for routine use

Method Meropenem disk inactivation

Test Reagents and materials

• TSB (2mL aliquots)• Meropenem disks (10mcg)• 1mcL and 10mcL inoculation loops• Normal saline (3-5mL)• MHA plates (100mm or 150mm)• Meropenem susceptible indicator strain E.coli

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Procedure:

1. One loopful (1mcL loop) bacteria + 2mL TSB2. Vortex 10-15s3. 10mcg meropenem disk added to it4. Incubate at 35 ± 2ºC for 4 hrs5. Simultaneously 0.5McFarland suspension of E.coli

ATCC 25922 prepared in NS.6. E.coli ATCC inoculated on MHA (lawn culture)7. Meropenem disk is removed from TSB by 10mL loop

and placed on above MHA plate: Incubate at 35 ± 2ºC for 18-24hrs

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Negative control

Positive control

Carbapenemase producer

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Test InterpretationCarbapenemase positive: Zone size of 6-15mm or presence of colonies within 16-18mm zone

Carbapenemase negative: Zone size ≥ 19mm

Indeterminate: 16-18mm

Reporting:Positive to be reported as “Carbapenemase detected”

Control strainsK.pneumoniae ATCC BAA1705 : Carbapenemase positiveK.pneumoniae ATCC BAA1706 : Negative

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THANK YOU

Md Ashraf Ali