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 2017.

Antimicrobial resistance in complex models of continuous infection is a current issue. The update 2017 course addresses about microbiological, epidemiological and clinical aspects useful for a current approach to infectious disease. During the last year, nosocomial pneumonia approach guides, recommendations for management of yeast and filamentous fungal infections, review papers on the empirical approach to peritonitis and extensive guidelines on stewardship have been published. HIV infection is being treated before and more intensively. The implementation of molecular biology, spectrometry and inmunology to traditional techniques of staining and culture achieve a better and faster microbiological diagnosis. Finally, the infection is increasingly integrated, assessing non-antibiotic aspects in the treatment.

[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.

Activity of linezolid and tedizolid against clinical isolates of methicillin-resistant and methicillin and linezolid resistant Staphylococcus aureus: an in vitro comparison.

OBJECTIVE: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Spain is approximately 20-30%. However, resistance to linezolid is rare, and the main reports are from nosocomial outbreaks. The objective of the present study was to compare the in vitro susceptibility of linezolid with that of tedizolid against MRSA isolates and methicillin-and linezolid-resistant isolates (MLRSA) mediated by the cfr gene. METHODS: The in vitro susceptibility of linezolid and tedizolid was determined using the E-test with 18 MRSA strains and 18 cfr-mediated MLRSA strains obtained from clinical isolates in the microbiology service of a tertiary university hospital. RESULTS: All MRSA strains were susceptible to both antibiotics. Analysis of the MRSA isolates revealed that the MIC50 and MIC90 of linezolid were 1.5 and 2 mg/L, respectively; those of tedizolid were 0.25 and 0.4 mg/L. The MIC50 and MIC90 of tedizolid remained at 0.75 and 1 mg/L against the MLRSA strains (MIC90 ≥ 8 mg/L). CONCLUSIONS: Both for MRSA and for MLRSA, the MICs obtained for tedizolid were at least 2 dilutions lower than those of linezolid, thus demonstrating between 2 and 4 times greater activity in vitro than linezolid.