Prevalence of Antibiotic Resistance Over Time in a Third-Level University Hospital.

This study evaluated the spread and possible changes in resistance patterns of ESKAPE bacteria to first-choice antibiotics from 2015 to 2019 at a third-level university hospital after persuasive stewardship measures were implemented. Isolates were divided into three groups (group 1, low drug-resistant; group 2, multidrug/extremely drug-resistant; and group 3, pan-resistant bacteria) and a chi-squared test (χ2) was applied to determine differences in their distributions. Among the 2,521 isolates, Klebsiella pneumoniae was the most frequently detected (31.1%). From 2015 to 2019, the frequency of isolates in groups 2 and 3 decreased from 70.1% to 48.6% (χ2 = 63.439; p < 0.0001). Stratifying isolates by bacterial species, for K. pneumoniae, the frequency of PDR isolates decreased from 20% to 1.3% (χ2 = 15.885; p = 0.003). For Acinetobacter baumannii, a statistically significant decrease was found in groups 2 and 3: from 100% to 83.3% (χ2 = 27.721; p < 0.001). Also, for Pseudomonas aeruginosa and Enterobacter spp., the frequency of groups 2 and 3 decreased from 100% to 28.3% (χ2 = 225.287; p < 0.001) and from 75% to 48.7% (χ2 = 15.408; p = 0.003), respectively. These results indicate that a program consisting of persuasive stewardship measures, which were rolled out during the time frame of our study, may be useful to control drug-resistant bacteria in a hospital setting.

Real-life 3D therapy failure: Analysis of NS5A 93H RAS plus 108 K polymorphism in complex with ombitasvir by molecular modeling.

We report a real-life 3D therapy failure in a patient treated with ombitasvir (OMV)/paritaprevir/ritonavir and dasabuvir without ribavirin (3D-R). He had therapy failure at week 12 after the end of treatment. We detected resistance-associated substitutions (RASs) plus polymorphisms on NS3, NS5A, and NS5B target regions by population sequencing (15% cut-off) at baseline, at relapse and during follow-up. About this, NS5A RASs generally persist longer than resistances in the other target genes and may impact treatment outcome. Therefore, to evaluate OMV drug-resistance mechanism, we studied the acquired RAS plus polymorphisms on NS5A phosphoprotein by computational studies. OMV showed a higher affinity towards baseline and 93H/108 K mutant structure (follow-up) with respect to 93H/R108 mutant structure (relapse) on phosphoprotein. By Molecular Dynamics simulations (MDs), structural information about the protein stability in presence of OMV were observed. According to our data, molecular modeling approach has proved to be a powerful method to evaluate the impact of these RASs plus specific amino acid (AA) changes on phosphoprotein.

Patterns of multi-drug resistant bacteria at first culture from patients admitted to a third level University hospital in Calabria from 2011 to 2014: implications for empirical therapy and infection control.

Surveillance of antimicrobial drug resistance is fundamental to guide empirical treatment. However, the European Antimicrobial Resistance Surveillance Network provides a general picture, which might not be applicable to clinical settings that are excluded from this survey. We evaluated resistance patterns of ESKAPE isolates over a four-year period in a third level University hospital in the province of Catanzaro (Southern Italy). In this retrospective study, we evaluated the frequency of ESKAPE isolates with different resistance patterns (group 1=low-resistant bacteria; group 2=multi-drug and extremely drug-resistant bacteria; group 3=pan-resistant bacteria), stratified by year (2011, 2012, 2013 and 2014), hospital units (intensive care units, medical and surgical units) and by sample type (urine, blood, wound swabs, respiratory samples, other samples). Chi square test was applied to find differences between isolates with different resistance patterns by hospital unit and by organs and systems. Cochran-Armitage trend test was applied to assess the trend in resistance patterns during the four years analyzed. Amongst 2385 isolates, Escherichia coli (38%) was the most frequent, followed by Pseudomonas aeruginosa (15%), Klebsiella pneumoniae (14%), Staphylococcus aureus (13%), Acinetobacter baumannii (9%), Enterococcus faecalis (8%) and Enterococcus faecium (3%). From 2011 to 2014, frequency of isolates in group 2 plus 3 decreased from 23% to 14% (chi square=55.093; p<0.0001), particularly for E. coli and K. pneumoniae, but the trend increased for S. aureus (from 5% in 2011 to 10% in 2014), and remained stable for the other species. Frequency of isolates in group 2 plus 3 was higher in intensive care units for K. pneumoniae (chi square =32.292; p<0.0001), A. baumannii (chi square =6.947; p<0.0001) and S. aureus (chi square =22.079; p<0.0001). It was also higher from blood than from different sources for most species.