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Evoluzione dell’antibiotico-resistenza: miti e realtàEvoluzione dell’antibiotico-resistenza: miti e realtà

Gian Maria RossoliniDip. Biologia Molecolare Sezione di MicrobiologiaUniversità di Siena

UO Microbiologia e VirologiaAzienda Osp-Univ Senese

MIC valuesInhibition zones

Broth or agar dilution tests

How do we define resistance?How do we define resistance?

Interpretation of resultsbased on clinical breakpoints

Interpretation of resultsbased on clinical breakpoints

Reference MIC/zone values for interpretation of the results of in vitro

susceptibility testing

Reference MIC/zone values for interpretation of the results of in vitro

susceptibility testing

The clinical breakpointsThe clinical breakpoints

Definition of susceptibility category (S/I/R) referred to clinical use

Definition of susceptibility category (S/I/R) referred to clinical use

Clinical breakpoints are defined by specific committees

Clinical breakpoints are defined by specific committees

Breakpoint committees in EuropeBreakpoint committees in Europe

Committee Country

BSAC United Kingdom

CA-SFM France

CRG The Netherlands

DIN Germany

NWGA Norway

SRGA Sweden

CLSI USA

Enterics / cefotaxime S< / R>BSAC United Kingdom 1 / 1

CA-SFM France 4 / 32CRG The Netherlands 4 / 8DIN Germany 2 / 8CLSI U.S.A. 8 / 32NWGA Norway 1 / 2SRGA Sweden 0.5 / 1

with different opinions...with different opinions...

Kahlmeter et al – JAC 2003

December 2004

The EUCAST MissionThe EUCAST Mission

• to harmonise clinical breakpoints in Europe

• to determine breakpoints for new antimicrobials

• to provide standardised methodology for AST

Setting clinical breakpoints for new drugs in Europe

Co-ordinated process between the Company, EMEA and EUCAST

When a Company applies for registration of a new agent: EUCAST defines the breakpoints EMEA decides on all other aspects

EUCAST breakpoints for new drugs are the only ones included in the SPC (Summary of Product Characteristics)

EUCAST clinical breakpointsEUCAST clinical breakpoints

Freely available on the WEBFreely available on the WEB

Defined by consensusDefined by consensus

Institutional decision body (industry has a consulting role but does not participate in the decisional process)

Institutional decision body (industry has a consulting role but does not participate in the decisional process)

Rationale for decision disclosed (rationale documents available)Rationale for decision disclosed (rationale documents available)

EUCAST vs. CLSI breakpoints:a remarkable diversity

Courtesy by G. Kahlmeter

EUCAST CLSI

S≤ R> S≤ R>

Cefepime 8 8 8 16

Ceftazidime 8 8 8 16

Imipenem 4 8 4 8

Meropenem 2 8 4 8

Pip/Tazo 16 16 64 64

Aztreonam 1 16 8 16

Ciprofloxacin 0.5 1 1 2

Gentamicin 4 4 4 8

Tobramycin 4 4 4 8

Amikacin 8 16 16 32

Colistin 2 2 2 4

EUCAST vs. CLSI breakpoints: Pseudomonas aeruginosa

For S: EUCAST 5/11 lowerFor S: EUCAST 5/11 lower For R: EUCAST 8/11 lowerFor R: EUCAST 8/11 lower

EUCAST vs. CLSI breakpoints: Enterobacteriaceae

(beta-lactams & quinolones)

EUCAST CLSI

S≤ R> S≤ R>

Cefepime 1 8 8 16

Ceftriaxone 1 2 8 32

Ceftazidime 1 8 8 16

Ertapenem 0.5 1 2 4

Imipenem 2 8 4 8

Meropenem 2 8 4 8

Pip/Tazo 8 16 16 64

Levofloxacin 1 2 2 4

Ciprofloxacin 0.5 1 1 2

For S: EUCAST 9/9 lowerFor S: EUCAST 9/9 lower For R: EUCAST 7/9 lowerFor R: EUCAST 7/9 lower

EUCAST CLSI

S≤ R> S≤ R>

Amikacin 8 16 16 32

Gentamicin 2 4 4 8

Tobramycin 2 4 4 8

Cotrimoxazole 2 4 2 2

Colistin 2 2 NA NA

Tigecycline 1 2 NA NA

For S: EUCAST 3/4 lowerFor S: EUCAST 3/4 lower

For R: EUCAST 3/4 lower, 1/4 higherFor R: EUCAST 3/4 lower, 1/4 higher

EUCAST vs. CLSI breakpoints: Enterobacteriaceae

(other agents)

EUCAST vs. CLSI

Will the change from CLSI to EUCAST breakpoint system significantly affect the epidemiology of antibiotic resistance?

EUCAST vs. CLSI

• A comparative analysis of AST results interpreted according to CLSI or EUCAST

• Data source: historical records from clinical microbiology service, Siena University Hospital (year 2008)

Pseudomonas aeruginosaGentamicin (N = 295)

2 4 8 16 32 64

EUCASTCLSI

MIC (mg/L)

EUCAST: RCLSI: I

Pseudomonas aeruginosaAmikacin (N = 296)

2 4 8 16 32 64

EUCASTCLSI

MIC (mg/L)

EUCAST: RCLSI: I

EUCAST: ICLSI: S

Pseudomonas aeruginosaCeftazidime (N = 294)

1 2 4 8 16 32

EUCASTCLSI

MIC (mg/L)

EUCAST: RCLSI: I

Pseudomonas aeruginosaMeropenem (N = 216)

2 4 8 16 32 64

EUCASTCLSI

MIC (mg/L)

EUCAST: ICLSI: S

Pseudomonas aeruginosaPip/Tazo (N = 289)

2 4 8 16 32 64

EUCASTCLSI

MIC (mg/L)

EUCAST: RCLSI: S

Pseudomonas aeruginosaAztreonam (N = 133)

1 2 4 8 16 32

EUCASTCLSI

MIC (mg/L)EUCAST: I

CLSI: S

Pseudomonas aeruginosaCiprofloxacin (N = 295)

0.25 0.5 1 2 4 8

EUCASTCLSI

MIC (mg/L)

EUCAST: RCLSI: I

EUCAST: ICLSI: S

Pseudomonas aeruginosaCLSI vs. EUCAST

% s

usc

epti

bil

ity

Antibiotics

MRSA impact (USA)MRSA impact (USA)

Boucher & Corey Clin Infec Dis 2008

a in hospital deaths

Resistance trends in major pathogens Europe

EARSS annual report, 2007

MRSAMRSA

Cou

ntr

ies

8/30

8/30

14/30 =

8/30

8/30

14/30 =

E. coli R to 3GCE. coli R to 3GC

23/30

1/30

6/30 =

23/30

1/30

6/30 =

2008:

2/31

10/31

19/31 =

2008:

2/31

10/31

19/31 =

2008:

21/30

0/30

9/31 =

2008:

21/30

0/30

9/31 =

Resistance trends in major pathogens Europe

EARSS annual report, 2007

MDR E. coli (R to 3GC,AG,FQ)

MDR E. coli (R to 3GC,AG,FQ)

24/30

0/30

6/30 =

24/30

0/30

6/30 =

Cou

ntr

ies

E. coli R to 3GCE. coli R to 3GC

23/30

1/30

6/30 =

23/30

1/30

6/30 =

The growing challenge of resistant Gram-negatives

• MRSA and VRE rates have leveled off or decreasing in several European countries

• Resistant Gram-negatives are increasing in most European countries

Rossolini & Mantengoli, CMI 2008

Major challenges:

• Enterobacteriaceae ESBL/AmpC, MDR, XDR (ESC/FQ/AG/NEM)

• Pseudomonas aeruginosa and Acinetobacter MDR, XDR (COL-S only)

EARSS databaseYear

% r

esis

tan

t to

3G

C

K. pneumoniaeK. pneumoniae

ESBLs: increasing trends

EARSS database

Year

% r

esis

tan

t to

3G

C E. coliE. coli

ESBLs: increasing trends

%

Spanu et al. - AAC 2002; Luzzaro et al. - JCM 2006; OASIS study, data on file

ESBL-producing Enterobacteriaceae , Italy

Suspect ESBL

2003: Proteus mirabilis (isolates from UTIs and ulcers)

Aztreonam

Ceftazidime

Cefotaxime

Ceftriaxone

Amoxi/Clav

Resistant to 3rd gen. ceph.but ESBL-negative

Ampicillin >128 RAmoxi/Clav 32 RPip/Tazo 4 SCephalotin 32 RCefotaxime 64 RCeftazidime 32 RCefepime 2Ertapenem 0.12 S

Amikacin 2 S Gentamicin 4 SCiprofloxacin >32 RLevofloxacin >32 R

MIC (mg/L)

RS

.

P. mirabilis resistant to

3rd gen. cephalosporins

Luzzaro et al – IJAA 2009

Same clone detected in LTCFs

By clonal expansionBy clonal expansion

Luzzaro et al – IJAA 2009

Clinical features of infections caused by the P. mirabilis CMY-16+

Mean age: 75±15 yrs (76±16 for ESBL+; 57±28 for susceptible strains)

Female/male ratio: 1.1(1.6 for ESBL+; 2.1 for susceptible strains)

Inpatients

LTCFs

HCAss

CA

51%37%

Patients

UTIs

LRTIs

SSSIs

BSIs

80%

Sources

2007-2008:P. mirabilis CMY+ spreading in Italy

2007-2008:P. mirabilis CMY+ spreading in Italy

Clonally related isolates detected in Greece and Poland: an internationally spreading clone

D’Andrea et al – unpublished

>30 cases from BSIs>30 cases from BSIs

Courtesy of Vincent Jarlier, Sept 2009 (modified)

ESBLs/AmpC and carbapenem overuse

Increased # ESBL/AmpC cases Increased Carb-R strains

Cross transmission

of Carb-R strains

Selection of Carb-R strains

Increased carbapenem

use

Production of:- CTX-M-15 ESBL- SHV-11- (OXA-9) (TEM-1)

Production of:- CTX-M-15 ESBL- SHV-11- (OXA-9) (TEM-1)

D’Andrea et al. – 19th ECCMID

2007-2008: emergence of MDR Klebsiella pneumoniae ERT-R from several hospitals …

Ampicillin >16 RAmoxi/Clav >16 RPip/Tazo >64 RCefotaxime >16 RCeftazidime >32 RCefepime >16 RAztreonam >16 RImipenem ≤1Meropenem 2-4Ertapenem >4 R

Amikacin >32 RGentamicin >8 RTobramycin >8 RCiprofloxacin >32 RLevofloxacin >32 RTMP/SXT >2 RTigecycline 1 - 2Colistin <1

MIC (mg/L)

Reduced porin expressionReduced porin expression

No carbapenemase act.No carbapenemase act.

Nationwideclonal spread

(ST37)

Nationwideclonal spread

(ST37)

Ampicillin >16 RAmoxi/Clav >16 RPip/Tazo >64 RCefotaxime >16 RCeftazidime >32 RCefepime >16 RAztreonam >16 RImipenem ≤1 RMeropenem 2-4 RErtapenem >4 RESBL positive

Amikacin >32 RGentamicin >8 RTobramycin >8 RCiprofloxacin >32 RLevofloxacin >32 RTMP/SXT >2 RTigecycline 1 - 2 SColistin <1

MIC (mg/L)

Klebsiella pneumoniae with reduced carbapenem susceptibility due to ESBL prod. + porin loss:

detection and reporting issues

Vitek-2 AES: changes to resistance to all carbapenemsVitek-2 AES: changes to resistance to all carbapenems

KPC-2K. oxytoca

KPC-2K. oxytoca

Yigit et al. AAC 2003

22% of isolates resistant to:- Aminoglycosides- Fluoroquonolones- 3rd 4th gener. Cephems- Carbapenems

Klebsiella pneumoniae

Susceptibility only to:- Colistin- Tigecycline

Due to spread of KPC carbapenemases

Brooklyn, New York …

Landman et al – JAC 2007

KPC-type carbapenemases in Israel: a major problem

Nationwide outbreak

Carbapenem resistance rates in K. pneumoniae from Israel:2006: 11%2007: 22%2008: 19%

EARSS database

KPC-type carbapenemases: a new pandemic?

Two cases, one with Israel connection

Clonally related

7 cases

4 from Greece2 from Israel

Clonally related

Nordmann et al. Lancet ID 2009

Villegas et al. AAC 2007Tsakris et al. JAC 2008

Hawser et al. IJAA 2009Literacka et al. AAC 2009

Intercontinental spread of ST258 KPC+ clone

KPC-type carbapenemases: emerging in Italy

Giani et al - JCM 2009

Florence

Oct 2008: KPC-3 positive K. pneumoniae ST258 isolated from a cIAI (high-level carbapenem resistance)

No epidemiological link with areas of endemicity, but patient cared for by a trainee from Israel

Lecco

May 2009: KPC positive K. pneumoniaePatient transferred from another hospitalLarge outbreak ongoing in that hospital (26 patients colonized or infected), variable carbapenem resistance

Luzzaro et al - unpublishedSantoriello et al - unpublished

Mostly by clonal spread (ST258), but at least two clones and also in Enterobacter

Additional reports

Carbapenem-resistant K. pneumoniae, GreeceCarbapenem-resistant K. pneumoniae, Greece

Production of

VIM-1 MBL

Production of

VIM-1 MBL

Multiple clones

Often susceptible

only to colistin and

tigecycline(XDR)

Vatopoulos et al. - Eurosurveillance 2008Psichogiou et al. – JAC 2008

KPC-type (active-site serine, class A)

OXA-type (active-site serine, class D)

Metallo-β-lactamases (class B)

Carbapenemases of clinical relevance

GM

COL

AK

TOB

FEPIPM

MEMCAZTZP

ATM

CIP

PRLLauretti et al. – AAC 1999

Cornaglia et al. – CID 2000

VERONA1997

VIM-1 MBL-producing index strainVR-143/97 (ser. O11; ST227)

VIM-1 MBL-producing index strainVR-143/97 (ser. O11; ST227)

Acquired MBLs in Pseudomonas aeruginosafirst Italian nationwide survey

VARESE 2.6%

PAVIA 1.3%

CREMONA 0.6%

PERUGIA 1.1%

SASSARI 0.9%

ROME 0.3% AVELLINO 1.4%

NEAPLES 9.2%

FOGGIA 1.2%

GENOA0%

TURIN0%

L’AQUILA0%

2004:Overall prevalence

1.3%

2004:Overall prevalence

1.3%

Rossolini et al. AAC 2008

2008:Overall prevalence

7%

2008:Overall prevalence

7%

Luzzaro et al. - unpublished

•CLSI soon replaced by EUCAST: resistance rates will be affected in some cases

•Resistance in Gram-negatives: now a major problem

•XDR phenotypes not only in Pseudomonas and Acinetobacter but also among enterobacteria

•Multiple resistance mechanisms: not easily deducible from the antibiotype

•Open issues in: lab detection, reporting, infection control and treatment

ConclusionsConclusions