Negative Pathogens from Hospital-Acquired Pneumonia in the UK and Ireland Since 2011 Beate Ritz*1, Nowel Redder1, Nathalie Dunkel1

P1865 Susceptibility of ceftobiprole and other beta-lactams against Gram- negative pathogens from hospital-acquired pneumonia in the UK and Ireland since 2011 Beate Ritz*1, Nowel Redder1, Nathalie Dunkel1

1 Correvio, Geneva, Switzerland Background: Ceftobiprole, an advanced-generation cephalosporin has been approved since 2013 in the United Kingdom and other European countries for the treatment of community- and hospital-acquired pneumonia (HAP) (excluding ventilator-associated pneumonia). BSAC respiratory surveillance programme includes ceftobiprole since 2011. Materials/methods: Gram-negative pathogens causing HAP were collected as part of the BSAC respiratory surveillance programme between 2011-12 to 2016-17. In total 1290 Escherichia coli, 789 Klebsiella pneumoniae and 1059 Pseudomonas aeruginosa were tested using the BSAC agar dilution method and susceptibility determined according to EUCAST breakpoints. Results: Virtually all E. coli and K. pneumoniae tested were susceptible to meropenem whereas the other beta- lactams tested had similar in vitro efficacy with the exception of amoxicillin/clavulanic acid. Meropenem had the lowest susceptibility to P. aeruginosa followed by ceftobiprole, piperacillin/tazobactam and ceftazidime.

Range MIC50 MIC90 %S Range MIC50 MIC90 %S Range MIC50 0.03- 0.03- 0.25- BPR 0.06 16 86.0 0.06 64 83.3 2 512 512 512 0.5- 0.25- AMC 16 128 47.5 2 64 76.7 NA NA 128 128 0.03- 0.03- 0.06- CAZ 0.25 4 85.5 0.25 16 84.0 2 256 512 512 0.125- 0.25- 0.125- TZP 2 16 88.9 4 32 81.5 4 512 512 512 0.008- 0.008- 0.032- MEM 0.016 0.032 100 0.032 0.032 98.8 0.25 0.125 512 64

*based on EUCAST PK/PD non-species specific susceptibility breakpoint of 4 mg/L; BPR: ceftobiprole; AMC: amoxicillin/clavulanic acid; CAZ: ceftazidime; TZP: piperacillin/tazobactam; MEM: meropenem Conclusions: On this large collection of Gram-negative pathogens, E. coli, K, pneumoniae and P. aeruginosa showed high and consistent susceptibility to ceftobiprole . Both E. coli and K. pneumoniae had similar susceptibility rates to ceftobiprole, ceftazidime or piperacillin/tazobactam. For P. aeruginosa, susceptibility rates were similar between meropenem, ceftobiprole and piperacillin/tazobactam. In this study, ceftazidime showed the highest in vitro efficacy against P. aeruginosa. Acknowledgments: Data were collected by BSAC as part of its Respiratory Surveillance Programme and are available online at www.bsacsurv.org.

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