Role of Hologic® Panther AptimaTM SARS-CoV-2 assay in the detection of SARS-CoV-2: screening or diagnostic technique?

During the multiple waves of COVID-19 suffered all over the world, having a rapid and sensitive diagnostic test has become a priority for microbiology laboratories. The AptimaTM SARS-CoV-2 transcription-mediated amplification (TMA) assay running on the Panther system (Hologic) was presented as a very good option to cover this need. To evaluate this system, 570 respiratory samples were included in the study and were processed both by the Panther (Hologic) system and by qRT-PCR (Thermo Fisher Science, Waltham, USA), current assay for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A high number of false positives (n=76) was obtained with Panther system (Hologic), but the number of false positives decreases as the relative light units (RLU) value increases. These results show that this technique can be a good option for sample screening but checking for positive results should be mandatory, especially those with low RLU values.

[Usefulness of MALDI-TOF and REP-PCR against PFGE for the epidemiological study of Acinetobacter baumannii]. / Utilidad de MALDI-TOF y REP-PCR frente a PFGE para el estudio epidemiológico de Acinetobacter baumannii.

OBJECTIVE: To evaluate the ability of MALDI-TOF MS and rep-PCR to discriminate Acinetobacter baumannii clones. METHODS: A total of 21 strains of A. baumannii with different epidemiological and phenotipycal characteristics were included in the study. All isolates were analyzed in parallel by MALDI-TOF MS and rep-PCR and the spectra obtained were compared with each other and with the results obtained by pulsed field gel electrophoresis (PFGE). Isolates with a similarity equal to or greater than 87% were considered to be part of the same clonal group. RESULTS: The analysis of the 21 isolates included in the study, resulted in 8 clonal groups using PFGE, 3 groups by MALDI-TOF MS and 7 groups by rep-PCR analysis. The isolates that formed the different groups by the 3 techniques used were totally different, so it can be concluded that there is no equivalence between the results obtained with the three typing methods used. CONCLUSIONS: Despite its simplicity, neither MALDI-TOF MS nor rep-PCR can at this time replace PFGE for the epidemiological study of A. baumannii.

In vitro activity of imipenem/relebactam against Gram-negative clinical isolates in two Spanish tertiary hospitals.

OBJECTIVE: The aim of this study was to analyze the activity of the imipenem-relebactam combination (IMI/REL) against a collection of multidrug-resist Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates. METHODS: The study was conducted in two tertiary hospitals in Spain and included 192 clinical isolates of these 3 genera (139 resistant and 53 susceptible to IMI). The MICs for IMI with and without REL (at a fixed concentration of 4 mg/L) were determined by a standard broth microdilution method according to international recommendations. RESULTS: All IMI-susceptible E. coli strains were also susceptible to IMI/REL. Enterobacterales resistant to IMI due to the production of carbapenemases, the MIC50 and MIC90 decreased from 64/256 with IMI to 8/64 mg/L with IMI/REL. This high activity was principally detected among isolates with KPC enzymes. Enterobacterales with class B carbapenemases, P. aeruginosa carrying VIM carbapenemase and A. baumannii strains showed no changes on IMI MIC50 or MIC90 after adding REL. Among P. aeruginosa strains without carbapenemase the MIC for IMI/REL was reduced between 1 to 5 dilutions. CONCLUSIONS: IMI/REL showed high activity against the strains that carry Klebsiella pneumoniae carbapenemase (KPC) and against carbapenem-resistant P. aeruginosa unrelated to the VIM enzyme, mainly AmpC beta lactamase associated with impermeability. Against strains carrying oxacillinase 48 (OXA-48) associated with extended-spectrum beta-lactamase (ESBL), IMI/REL presented activity only slightly better than IMI and had no beneficial effect superior to IMI against A. baumannii.

[Update in Infectious Diseases 2016]. / Actualización en Patología Infecciosa 2016.

Antimicrobial resistance increases it health, social and economic impact. in all areas (state, regional and local), initiatives to try to contain the problem of resistance arise. In the update of this year 2016, we study microbiological, epidemiological and clinical aspects of multi-resistant bacteria, as well as resources for therapeutic approach, from ancient to modern drugs from therapeutic combinations to optimization Stewardship programs. In the case of fungal infection, we analyze clinical scenarios with different species in yeast or new clinical settings in filamentous fungi. Taking paediatric population, homologies and differences with adults in invasive fungal infection were compared. Finally in the field of parasitology, treatment of severe malaria imported or that resistant to antimalarial drugs were reviewed.

[Clostridium difficile, are all our patients diagnosed?]. / Clostridium difficile, ¿están todos los que son?

BACKGROUND: A close correlation between clinical and microbiological diagnosis in Clostridium difficile infection (CDI) is very important to identify how severe is this health problem, and to approach its correct management of it, individually and as a population problem. OBJETIVES: a) To evaluate if there is an adequate correlation between the microbiological and clinical diagnosis in CDI patients; b) to determine if the discordance between the microbiological and clinical diagnosis could be associated with different clinical patient characteristics, therapeutic attitudes, and outcomes. PATIENTS AND METHODS: A retrospective study was conducted, using clinical and epidemiologic data, on inpatients with a microbiological diagnosis of CDI in 2013 in the Hospital Clínico San Carlos in Madrid (Spain), depending on whether their clinical ICD diagnosis was included. RESULTS: From a total of 33,317 discharged patients, 204 patients had a CDI diagnosis. Only 51.5% patients had this diagnosis stated in their discharge report. Patients on whom the clinical diagnosis was included, were older, had higher level of dependence (P<.05), and received treatment for CDI more frequently (P<.001) than patients who did not have the clinical diagnosis included. A lower treatment rate was associated with a higher mortality (P=.032) CONCLUSIONS: Nearly half of patients with a microbiological diagnosis of CDI did not have the clinical diagnosis included in their clinical report. Patients without the clinical diagnosis were younger, had less disability, and received specific antibiotics for CDI less frequently. Not receiving specific antibiotics for CDI was associated with higher mortality.