U.S. Food and Drug Administration

1. U.S. Food and Drug Administration Notice: Archived Document The content in this document is provided on the FDA’s website for reference purposes only. It was current when produced, but is no longer maintained and may be outdated.

2. Aspects of the use of 4 GCs in human and veterinary medicine in Europe Veterinary Medicine Advisory Committee Public Hearing, 25 September 2006 Pr. André Bryskier, MD

3. Aspects under review • Characterization of C3’quaternary ammonium cephalosporins class (4GCs) • Clinical indications of 4GCs in Europe • Mechanisms of resistance of 4GCs • Susceptibility surveillance programs for E.coli and non typhoidal Salmonella • Summary and conclusions

4. I. Classification - -lactam family • Penams (Penicillins) • Cephems (Cephalosporins, Cephamycins, Oxa-1-cephems, • Carbacephems, Isocephems) • Monocyclic β-lactams (monobactams) • Penems (carbapenems) • C3’quaternary ammonium cephalosporins (4GCs) belong to the Cephem group. • Together with 3GCs, they are identified as extended spectrum cephalosporins (ESC)

5. I. Characterization – Chemical structure of ESC CH CO N H CH CO S N H S R7 R7 R N N+ N O O COO- COO- Monoanionic cephems (3GCs) Zwitterionic cephems (4GCs) Cefotaxime Ceftriaxone Ceftiofur* Cefovecin* Cefepime Cefpirome Cefquinome* CH CO N H S COO- N+ N O COO- Dianionic cephems (3GCs) Ceftazidime *Cephems only used in veterinary medicine

6. I. Characterization – Dual mode of action • Rapid penetration of the outer membrane • Rapid crossing of the periplasmic space • Low affinity for β- lactamases • High affinity for Penicillin Binding Proteins (PBPs) Nikaido et al., 1990; Pucci et al. 1991

7. II. Clinical indications of 4GCs in human medicine in Europe

8. II. Clinical indications of cefquinome in veterinary medicine in Europe

9. III. Resistance mechanisms • Outer-membrane Minor epidemiological impermeability relevance in Gram negative • Efflux pump • β-lactamasesMajor epidemiological relevance in Gram negative • Penicillin Binding Relevance in Gram positive Protein (PBP) alterations

10. III. Resistance mechanisms – Major β-lactamases β-lactamases are divided in four classes (Ambler classification) • Class A: Narrow- spectrum β-lactamases: TEM-1, TEM-2, SHV-1 ESBLs: TEM, SHV-derivatives, CTX-M • Class B: Metallo enzymes: carbapenemases • Class C: AmpC: FOX, MOX, CMY, ACC, etc. • Class D: Oxacillinases Most important beta-lactamases are cephalosporinases (AmpC) and Extended Spectrum Beta-Lactamases (ESBLs)

11. III. Mechanisms of resistance – Characteristics of ESBLs and AmpC Nordmann P, 1998

12. III. Mechanisms of resistance –Prevalence of AmpC in Europe (-): sporadic cases have been reported Philippon A et al., 2002

13. III. Mechanisms of resistance - Prevalence of ESBLs in Europe (-): sporadic cases have been reported Lahey.org; Batchelor M et al., 2005; Miriagou V et al., 2004

14. III. Mechanisms of resistance – Variety of ESBLs and AmpC ESBL AmpC Great variety in human medicine Lahey.org; Batchelor M et al., 2005

15. III. Mechanisms of resistance - Conclusions • ESBL: • Broad spectrum of hydrolysis except carbapenems • Identified since 1988 in E.coli in human medicine • Great variety in human isolates • Sporadic cases in livestockin Europe • AmpC • Broad spectrum of hydrolysis except 4GCs and carbapenems • Identified since 1990 in human medicine • Some variants in human isolates • Sporadic cases in livestock in Europe

16. IV. Susceptibility surveillance programs for E.coli and non typhoidal Salmonella • Published susceptibility surveillance data to 4GCs (cefepime) are limited • T.E.S.T and SENTRY surveillance programs identified as sources for human medicine • EASSA surveillance program for veterinary medicine • European surveillance programs are testing 3GCs as representatives of ESC • EARSS (ceftazidime, ceftriaxone, cefotaxime), Enter-net (cefotaxime)

17. IV. Cefepime susceptibility surveillance for E.coli and non typhoidal Salmonella • T.E.S.T Tigecycline Evaluation and Surveillance Trial • Collection of human clinical isolates from blood, respiratory tract, urine and other infections (skin, wound, fluids) • MIC determination of cefepime as tigecycline comparator by broth micro-dilution technique • Cefepime MIC interpretive criteria R≥ 32 µg/ml • SENTRY surveillance program • Funded 1993, • Collection of human clinical isolates • MIC determination of cefepime by broth micro-dilution technique • Cefepime MIC interpretative criteria R≥ 32 µg/ml • EASSA European Antimicrobial Susceptibility Surveillance in Animals • Collection of foodborne and commensals bacteria from healthy animals at slaughter • MIC determination of cefepime by broth micro-dilution technique • Cefepime MIC interpretative criteria R≥ 32 µg/ml

18. IV.Cefepimesusceptibility surveillance for E.coli • T.E.S.T data • Cefepime susceptibility data and percent of resistant Enterobacteriaceae and • E.coli humanclinical isolates collected in Europe in 2004-2005 Hoban D et al., E-326, ICAAC 2005

19. IV. Cefepime susceptibility surveillance for E.coli and Salmonella • SENTRY data Percent of resistant E.coli and Salmonella spp. isolates collected in pediatric infections in Europe in 2004 to cefepime Fedler KA et al., 2006

20. IV. Cefepime susceptibility surveillance for E.coli and Salmonella • EASSA data Susceptibility ofE.coli and Salmonella spp. isolates collected from healthy livestock at slaughter to cefepime No resistant isolate reported Bywater et al., 2004; *: unpublished data

21. IV. Susceptibility surveillance - European surveillance programs • EARSS European Antimicrobial Resistance Surveillance program • Funded by European Commission in 1999, partner of WHO • On going collection of antimicrobial susceptibility tests of invasive bacteria (Blood culture and CSF) • Enter-net • International surveillance network for enteric infections Salmonella, verotoxigenic E.coli (VTEC) and Campylobacter • Funded by European Commission in 1993, partner of WHO • International database of fully characterized bacteria including data on epidemiology and antibiotic resistance

22. IV. Surveillance surveillance - European surveillance programs • EARSS data • Proportion of invasive E.coli isolates with resistance to 3GCs in 2004 In 2004 : 30119 isolates collected Average resistance rate : 2.9% Resistance breakpoints 1-32 µg/ml

23. IV.Susceptibility surveillance - European surveillance programs • Enter-net data • Percent of resistant Salmonella spp isolates to ampicillin (21.7 to 27.5 %) • and cefotaxime (0.2 to 0.4%) from 2001 to 2004 N=6396 N=10145 N=8669 N=10078 *: European enlargement and inclusion of Australia

24. IV. Susceptibility surveillance - European surveillance programs • Enter-net data Percent of resistant isolates of E.coli (VTEC, environmental and animal reservoirs) to cefotaxime from 2005 to first quarter 2006 cefotaxime R breakpoint > 1µg/ml No resistance to ESC in Europe

25. IV. Susceptibility surveillance - Conclusions • Resistance to ESC in human clinical cases • Approximately 3 % in E.coli isolated from invasive infections • Very low in Salmonella (< 1%) • Not found in VTEC (0%)

26. V. Summary and conclusions • 4GC structure confers a low affinity for most β-lactamases including AmpC • Resistance due to ESBL emerged about 15 years ago and evolved to a great variety in human isolates • Only sporadic cases reported of ESBL and AmpC in veterinary medicine in Europe • No 4GC resistance in E.coli and Salmonella spp. in animals at slaughter The use of cefquinome for more than 10 years in Europe has not promoted the emergence of resistance in human medicine.