presented base pair insertion/deletions, leading to different read- ing frames (Figure S2). These findings are in apparent contradiction with the proposed activity of these alleles. The present results show the high prevalence of CrpP in Pseudomonadaceae as well as its expansion towards other rel- evant genera (i.e. Acinetobacter), highlighting the presence of CrpP within pKC102-derived ICEs, and thereby suggesting that the origin of CrpP is from plant-related bacterial communities. Furthermore, as small amino acid differences in antibiotic- modifying enzymes may alter both enzyme activity levels and substrate specificity, 4,5 the presence of a huge number of CrpP alleles might result in differences in the quinolones inactivated, as well as in their levels of activity (probably including inactive variants). Acknowledgements I thank Donna Pringle for idiomatic corrections. Funding The study was supported by the author’s own funds. Transparency declarations None to declare. Supplementary data Figures S1 and S2 are available as Supplementary data at JAC Online. References 1 Ch avez-Jacobo VM, Hern andez-Ram  ırez KC, Romo-Rodr  ıguez P et al. CrpP is a novel ciprofloxacin-modifying enzyme encoded by the Pseudomonas aer- uginosa pUM505 plasmid. Antimicrob Agents Chemother 2018; 62: e02629-17. 2 Ch avez-Jacobo VM, Hern andez-Ram  ırez KC, Silva-S anchez J et al. Prevalence of the crpP gene conferring decreased ciprofloxacin susceptibility in enterobacterial clinical isolates from Mexican hospitals. J Antimicrob Chemother 2019; 74: 1253–9. 3 Klockgether J, Reva O, Larbig K et al. Sequence analysis of the mobile ge- nome island pKLC102 of Pseudomonas aeruginosa C. J Bacteriol 2004; 186: 518–34. 4 Robicsek A, Strahilevitz J, Jacoby GA et al. Fluoroquinolone-modifying en- zyme: a new adaptation of a common aminoglycoside acetyltransferase. Nat Med 2006; 12: 83–8. 5 Kim DW, Thawng CN, Choi JH et al. Polymorphism of antibiotic-inactivating enzyme driven by ecology expands the environmental resistome. ISME J 2018; 12: 267–76. J Antimicrob Chemother 2019; 74: 3399–3401 doi:10.1093/jac/dkz318 Advance Access publication 1 August 2019 Successful treatment with cefiderocol for compassionate use in a critically ill patient with XDR Acinetobacter baumannii and KPC-producing Klebsiella pneumoniae: a case report Enrico Maria Trecarichi 1 *, Angela Quirino 2 , Vincenzo Scaglione 1 , Federico Longhini 3 , Eugenio Garofalo 3 , Andrea Bruni 3 , Eugenio Biamonte 3 , Rosaria Lionello 1 , Francesca Serapide 1 , Maria Mazzitelli 1 , Nadia Marascio 2 , Giovanni Matera 2 , Maria Carla Liberto 2 , Paolo Navalesi 3 and Carlo Torti 1 on behalf of the IMAGES Group† 1 Unit of Infectious and Tropical Diseases, Department of Medical and Surgical Sciences, ‘Magna Graecia’ University, Catanzaro, Italy; 2 Unit of Clinical Microbiology, Department of Health Sciences, ‘Magna Graecia’ University, Catanzaro, Italy; 3 Unit of Intensive Care, Department of Medical and Surgical Sciences, ‘Magna Graecia’ University, Catanzaro, Italy *Corresponding author. E-mail: em.trecarichi@unicz.it †Other members are listed in the Acknowledgements section. Sir, Cefiderocol is a new siderophore cephalosporin, with potent activity against MDR Gram-negative bacilli. It is particularly active against XDR Acinetobacter baumannii (Ab) infections, for which treatment options are quite limited. 1–3 Herein, we describe a case of an adult male patient with severe H1N1 influenza complicated by ventilator-associated pneumonia (VAP) and bloodstream infection (BSI) caused by XDR Ab and carbapenemase-producing Klebsiella pneumoniae (KPC-Kp). Nothing remarkable was in his medical history apart from favism and Aarskog–Scott syndrome. In February 2019, due to the onset of acute respiratory failure, he was admitted to a peripheral primary ICU where he was diag- nosed with H1N1 influenza virus complicated by bilateral pneumo- nia. The patient was immediately intubated and then transferred to our hospital where extracorporeal membrane oxygenation (ECMO) was started. Also, treatment with intravenous zanamivir and empirical antimicrobial therapy with piperacillin/tazobactam, clarithromycin and linezolid were prescribed. Zanamivir was obtained through the compassionate-use programme run by GlaxoSmithKline (Brentford, UK). Table 1 shows SOFA scores and laboratory results during the in- patient stay. 4 V C The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com. Research letters JAC 3399 Downloaded from https://academic.oup.com/jac/article/74/11/3399/5542620 by guest on 12 July 2022