To describe and characterize the emergence of resistance to ceftolozane/tazobactam, ceftazidime/avibactam and imipenem/relebactam in a patient receiving ceftazidime/avibactam treatment for an MDR Pseudomonas aeruginosa CNS infection. One baseline (PA1) and two post-exposure (PA2 and PA3) isolates obtained before and during treatment of a nosocomial P. aeruginosa meningoventriculitis were evaluated. MICs were determined by broth microdilution. Mutational changes were investigated through WGS. The impact on β-lactam resistance of mutations in bla_PDC and mexR was determined through cloning experiments and complementation assays. Isolate PA1 showed baseline resistance mutations in DacB (I354A) and OprD (N142fs) conferring resistance to conventional antipseudomonals but susceptibility to ceftazidime/avibactam, ceftolozane/tazobactam and imipenem/relebactam. Post-exposure isolates showed two divergent ceftazidime/avibactam-resistant phenotypes associated with distinctive mutations affecting the intrinsic P PDC β-lactamase (S254Ins) (PA2: ceftolozane/tazobactam and ceftazidime/avibactam-resistant) or MexAB-OprM negative regulator MexR in combination with modification of PBP3 (PA3: ceftazidime/avibactam and imipenem/relebactam-relebactam-resistant). Cloning experiments demonstrated the role of PDC modification in resistance to ceftolozane/tazobactam and ceftazidime/avibactam. Complementation with a functional copy of the mexR gene in isolate PA3 restored imipenem/relebactam susceptibility. We demonstrated how P. aeruginosa may simultaneously develop resistance and compromise the activity of new β-lactam/β-lactamase inhibitor combinations when exposed to ceftazidime/avibactam through selection of mutations leading to PDC modification and up-regulation of MexAB-OprM-mediated efflux.

Different tests for human papillomavirus (HPV) screening are commercially available, detecting high‐risk oncogenic HPV types with a pool of genotype‐specific probes. However, it is necessary to establish reliable methods for the identification of individual genotypes. The purpose of this study was to compare three different commercial methods for HPV genotyping: INNO‐LiPA HPV Genotyping v2 (LiPA), Linear Arrays HPV Genotyping Test (LA) and Clinical Arrays Human Papillomavirus (CA). A total of 83 HPV DNA‐positive samples by hybrid capture method were genotyped (82, 78 and 81 by LiPA, LA and CA, respectively). Comparison analysis was limited to the HPV genotypes common to the three assays. There were concordant results (absolute agreement between assays) in 31 samples (39.7%) and compatible results (correspondence for some but not all genotypes) were found in 44 samples (56.4%). Only three samples (3.8%) were considered as discordant (did not show any similarity between the tests). Analyzing kappa values we have a very good agreement (>0.8) for HPV16 and HPV31 and good agreement (0.6–0.8) for HPV types 6, 18, 53 and 66 when all methods are compared. We conclude that all genotyping methods tested are highly comparable and suitable for clinical and epidemiological studies.