Validation of MALDI-TOF for the early detection of the ST175 high-risk clone of Pseudomonas aeruginosa in clinical isolates belonging to a Spanish nationwide multicenter study.

Introduction: Pseudomonas aeruginosa causes severe infections, particularly in healthcare settings and immunocompromised patients in whom MDR and XDR isolates are more prevalent. The aim of this study is to validate a method based on MALDI-TOF spectra analysis for early detection of the ST175 high-risk clone (HRC).

Methods: The MALDI-TOF spectra of the first 10 P.

[Gonococcal pelviperitonitis: a diagnostic challenge].

Neisseria gonorrhoeae is the second most common etiological agent of pelvic inflammatory disease and is currently un-derdiagnosed due to its asymptomatic presentation in 50% of cases. When the disease presents, it may appear in the form of acute abdomen and normal imaging tests, making it a major diagnostic challenge. We present four cases of acute gonococcal peritonitis.

[Analysis of the demand for detection of SARSCoV-2 in a health area of Spain].

Objective: Since the discovery of the SARS-CoV-2 virus, the polymerase chain reaction technique (RT-PCR) has become the fundamental method for diagnosing the disease in its acute phase. The objective is to describe the demand-based series of RT-PCR determinations received at a Microbiology Service at a third-level reference hospital for a health area for three months spanning from the onset of the epidemic by SARS-CoV-2.

Methods: A retrospective analysis of the total of the RT-PCR requested in the Microbiology Service analyzed from 02/25/2020 to 05/26/2020 (90 days) has been carried out.

Use of MALDI-TOF MS (Bruker Daltonics) for identification of Mycobacterium species isolated directly from liquid medium.

Objectives: The aim of this study was to describe the evaluation of the use of MALDI-TOF MS for the identification of non-tuberculous mycobacteria (NTM) and Mycobacterium tuberculosis directly from liquid MGIT cultures from January 2017 to December 2017.

Material/methods: A total of 155 isolates (mainly respiratory) were analyzed by MALDI-TOF MS (Bruker Daltonics) directly from MGIT liquid medium with a previous extraction procedure.

Results: MALDI-TOF MS generated acceptable scores for 152 isolates (98.

Characterization of AmpC β-lactamase mutations of extensively drug-resistant Pseudomonas aeruginosa isolates that develop resistance to ceftolozane/tazobactam during therapy.

Introduction: We characterized AmpC β-lactamase mutations that resulted in ceftolozane/tazobactam resistance in extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates recovered from patients treated with this agent from June 2016 to December 2018.

Methods: Five pairs of ceftolozane/tazobactam susceptible/resistant P. aeruginosa XDR isolates were included among a total of 49 patients treated.