Genetic analysis of vancomycin-variable Enterococcus faecium clinical isolates in Italy.

PURPOSE: To investigate the occurrence of vancomycin-variable enterococci (VVE) in a hospital in central Italy. METHODS: vanA positive but vancomycin-susceptible Enterococcus faecium isolates (VVE-S) were characterized by antibiotic susceptibility tests, molecular typing (PFGE and MLST), and WGS approach. The reversion of VVE-S to a resistant phenotype was assessed by exposure to increasing vancomycin concentrations, and the revertant isolates were used in filter mating experiments. qPCR was used to analyze the plasmid copy number. RESULTS: Eleven putative VVE-S were selected. WGS revealed two categories of vanA cluster plasmid located: the first type showed the lack of vanR, the deletion of vanS, and an intact vanH/vanA/vanX cluster; the second type was devoid of both vanR and vanS and showed a deletion of 544-bp at the 5'-end of the vanH. Strains (n = 7) carrying the first type of vanA cluster were considered VVE-S and were able to regain a resistance phenotype (VVE-R) in the presence of vancomycin, due to a 44-bp deletion in the promoter region of vanH/vanA/vanX, causing its constitutive expression. VVE-R strains were not able to transfer resistance by conjugation, and the resistance phenotype was unstable: after 11 days of growth without selective pressure, the revertants were still resistant but showed a lower vancomycin MIC. A higher plasmid copy number in the revertant strains was probably related to the resistance phenotype. CONCLUSION: We highlight the importance of VVE transition to VRE under vancomycin therapy resulting in a potential failure treatment. We also report the first-time identification of VVE-S isolates pstS-null belonging to ST1478.

Central venous catheter unrelated candidemia influences the outcome of infection in patients with solid tumors.

Systemic infections due to Candida spp. is common among immunocompromised patients, including those with solid tumors (ST). Clinical characteristics of candidemia in 114 patients with ST were compared with those of 249 candidemic patients without ST (non-ST). Patients with ST were more likely to be hospitalized in medical departments, to have a significantly higher Charlson's score and to undergo a significantly later central venous catheter (CVC) removal (P < 0.001). Similarly, the use of total parenteral nutrition was more common in ST patients (P = 0.026). Although there was a trend toward a more appropriate use of antifungal therapy in ST (60%) than in non-ST patients (49%), the difference was not statistically significant (P = 0.059). Thirty-day mortality was significantly higher in ST (49%) than in non-ST patients (36%, P = 0.016). Multivariate analysis showed that either higher age or septic shock was an independent risk factor for mortality in both groups of patients. Conversely, a CVC-unrelated candidemia represented an independent risk factor for mortality in ST patients (HR 3.581 [CI 95% 1.412-9.087, P = 0.007]). Overall, these data show that candidemia in ST patients is characterized by an extremely high mortality rate.

High Rate of Ceftobiprole Resistance among Clinical Methicillin-Resistant Staphylococcus aureus Isolates from a Hospital in Central Italy.

Ceftobiprole is a fifth-generation cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA). One-year surveillance at the Regional Hospital of Ancona (Italy) disclosed a 12% ceftobiprole resistance rate (12/102 isolates; MIC, ≥4 mg/liter). Epidemiological characterization demonstrated that the resistant isolates all belonged to different clones. Penicillin-binding protein (PBP) analysis showed substitutions in all PBPs and a novel insertion in PBP2a. The mecB and mecC genes were not detected. Ceftobiprole susceptibility screening is essential to avoid therapeutic failure and the spread of ceftobiprole-resistant strains.

Persistence and evolution of linezolid- and methicillin-resistant Staphylococcus epidermidis ST2 and ST5 clones in an Italian hospital.

OBJECTIVES: Staphylococcus epidermidis is a member of the human skin microbiome. However, in recent decades, multidrug-resistant and hospital-adapted S. epidermidis clones are increasingly involved in severe human infections associated with medical devices and in immunocompromised patients. In 2016, we reported that a linezolid- and methicillin-resistant S. epidermidis ST2 clone, bearing the G2576T mutation, was endemic in an Italian hospital since 2004. This study aimed to retrospectively analyse 34 linezolid- and methicillin-resistant S. epidermidis (LR-MRSE) strains collected from 2018 to 2021 from the same hospital. METHODS: LR-MRSE were typed by Pulsed-Field Gel Electrophoresis and multilocus sequence typing and screened for transferable linezolid resistance genes. Representative LR-MRSE were subjected to whole-genome sequencing (WGS) and their resistomes, including the presence of ribosomal mechanisms of linezolid resistance and of rpoB gene mutations conferring rifampin resistance, were investigated. RESULTS: ST2 lineage was still prevalent (19/34; 55.9%), but, over time, ST5 clone has been widespread too (15/34; 44.1%). Thirteen of the 34 isolates (38.2%) were positive for the cfr gene. Whole-genome sequencing analysis of relevant LR-MRSE displayed complex resistomes for the presence of several acquired antibiotic resistance genes, including the SCCmec type III (3A) and SCCmec type IV (2B) in ST2 and ST5 isolates, respectively. Bioinformatics and polymerase chain reaction (PCR) mapping also showed a plasmid-location of the cfr gene and the occurrence of previously undetected mutations in L3 (ST2 lineage) and L4 (ST3 lineage) ribosomal proteins and substitutions in the rpoB gene. CONCLUSION: The occurrence of LR-MRSE should be carefully monitored in order to prevent the spread of this difficult-to-treat pathogen and to preserve the efficacy of linezolid.

Candidemia in intensive care units over nine years at a large Italian university hospital: Comparison with other wards.

PURPOSE: Candidemia is an alarming problem in critically ill patients including those admitted in intensive care units (ICUs). We aimed to describe the clinical and microbiological characteristics of bloodstream infections (BSIs) due to Candida spp. in patients admitted to ICUs of an italian tertiary referral university hospital over nine years. METHODS: A retrospective observational study of all cases of candidemia in adult patients was carried out from January 1, 2010 to December 31, 2018 at a 980-bedded University Hospital in Ancona, Italy, counting five ICUs. The incidence, demographics, clinical and microbiologic characteristics, therapeutic approaches and outcomes of ICU-patients with candidemia were collected. Non-ICU patients with candidemia hospitalized during the same time period were considered for comparison purposes. Early (7 days from the occurrence of the episode of Candida BSI) and late (30 days) mortality rates were calculated. RESULTS: During the study period, 188/505 (36%) episodes of candidemia occurred in ICU patients. Cumulative incidence was 9.9/1000 ICU admission and it showed to be stable over time. Candida albicans accounted for 52% of the cases, followed by C. parapsilosis (24%), and C. glabrata (14%). There was not a significant difference in species distribution between ICU and non-ICU patients. With the exception of isolates of C. tropicalis which showed to be fluconazole resistant in 25% of the cases, resistance to antifungals was not of concern in our patients. Early and late mortality rates, were 19% and 41% respectively, the latter being significantly higher than that observed in non-ICU patients. At multivariate analysis, factors associated with increased risk of death were septic shock, acute kidney failure, pulmonary embolism and lack of antifungal therapy. The type of antifungal therapy did not influence the outcome. Mortality did not increased significantly over time. CONCLUSION: Neither cumulative incidence nor crude mortality of candidemia in ICU patients increased over time at our institution. However, mortality rate remained high and significantly associated with specific host-related factors in the majority of cases.

Carriage of Carbapenem-Resistant Enterobacterales in Adult Patients Admitted to a University Hospital in Italy.

The emerging spread of carbapenemase-producing Enterobacterales (CPE) strains, in particular, Klebsiella pneumoniae and Escherichia coli, has become a significant threat to hospitalized patients. Carbapenemase genes are frequently located on plasmids than can be exchanged among clonal strains, increasing the antibiotic resistance rate. The aim of this study was to determine the prevalence of CPE in patients upon their admission and to analyze selected associated factors. An investigation of the antibiotic resistance and genetic features of circulating CPE was carried out. Phenotypic tests and molecular typing were performed on 48 carbapenemase-producing strains of K. pneumoniae and E. coli collected from rectal swabs of adult patients. Carbapenem-resistance was confirmed by PCR detection of resistance genes. All strains were analyzed by PCR-based replicon typing (PBRT) and multilocus sequence typing (MLST) was performed on a representative isolate of each PBRT profile. More than 50% of the strains were found to be multidrug-resistant, and the bla KPC gene was detected in all the isolates with the exception of an E. coli strain. A multireplicon status was observed, and the most prevalent profile was FIIK, FIB KQ (33%). MLST analysis revealed the prevalence of sequence type 512 (ST512). This study highlights the importance of screening patients upon their admission to limit the spread of CRE in hospitals.

Characterization and Clonal Diffusion of Ceftaroline Non-Susceptible MRSA in Two Hospitals in Central Italy.

BACKGROUND: Ceftaroline represents a novel fifth-generation cephalosporin to treat infections caused by methicillin-resistant Staphylococcus aureus (MRSA). METHODS: Ceftaroline susceptibility of 239 MRSA isolates was assessed by disk diffusion and a MIC test strip following both EUCAST and CLSI guidelines. Non-susceptible isolates were epidemiologically characterized by pulsed-field gel electrophoresis, spa typing, and multilocus sequence typing, and further investigated by PCR and whole genome sequencing to detect penicillin-binding protein (PBP) mutations as well as antibiotic resistance and virulence genes. RESULTS: Fourteen isolates out of two hundred and thirty-nine (5.8%) were non-susceptible to ceftaroline (MIC > 1 mg/L), with differences between the EUCAST and CLSI interpretations. The characterized isolates belonged to seven different pulsotypes and three different clones (ST228/CC5-t041-SCCmecI, ST22/CC22-t18014-SCCmecIV, and ST22/CC22-t022-SCCmecIV), confirming a clonal diffusion of ceftaroline non-susceptible strains. Mutations in PBPs involved PBP2a for ST228-t041-SCCmecI strains and all the other PBPs for ST22-t18014-SCCmecIV and ST22-t022-SCCmecIV clones. All isolates harbored antibiotic resistance and virulence genes with a clonal distribution. CONCLUSION: Our study demonstrated that ceftaroline non-susceptibile isolates belonged not only to ST228 strains (the most widespread clone in Italy) but also to ST22, confirming the increasing role of these clones in hospital infections.

Species distribution and antifungal susceptibilities of bloodstream Candida isolates: a nine-years single center survey.

This study analyzed the epidemiology of bloodstream infections due to Candida spp. in a tertiary referral hospital of Ancona, Italy, and their susceptibility to antifungals. The retrospective observational study from January 2010 to December 2018 identified 504 episodes of candidemia in 461 patients. Although Candida albicans remained the species most frequently isolated, Candida spp. other than C. albicans caused 49% of the overall episodes of candidemia. According to CLSI interpretation, most of the isolates resulted susceptible to antifungals. Azoles vs Candida tropicalis represented an exception. Echinocandin non-susceptibility was rare across the species. In conclusion, with the exception of C. tropicalis, the isolation of a non-susceptible Candida strains against azoles, echinocandins and amphotericin B was a rare event.

Comparative evaluation of Xpert MTB/RIF and the new Xpert MTB/RIF ultra with respiratory and extra-pulmonary specimens for tuberculosis case detection in a low incidence setting.

BACKGROUND: The Xpert MTB/RIF assay (Xpert) is an automated molecular test for the detection of tuberculosis and rifampin resistance (RIF-R), but it lacks sensitivity in smear-negative samples and some limitations in determination of RIF-R have also been reported. The new Xpert MTB/RIF Ultra (Ultra) was developed to overcome these limitations. We aimed to compare Ultra and Xpert diagnostic accuracy setting culture and drug susceptibility testing as reference standards. METHODS: A retrospective analysis was performed on 359 consecutive, respiratory (269) and extrapulmonary (90) specimens collected from 340 patients investigated for TB along a two-year period. Patients presenting at primary health-care centres and hospitals were recruited on the basis of symptoms and abnormal X-ray imaging. One-hundred seventy-four subjects were identified to have active tuberculosis by culture and 2 were MDR. FINDINGS: Sensitivities of Ultra and Xpert were 87% and 75% for the 48 individuals with smear-negative and culture-positive respiratory TB (difference of 12%, 95% CI 3 to 21); 95% and 72% for the 40 individuals with smear-negative and culture-positive extrapulmonary disease (22%, 95% CI 10 to 34); and 95% and 86%, respectively, across all 174 individuals with culture-positive samples (8.5%, 95% CI 4.5 to 12.5). Specificities of Ultra and Xpert for tuberculosis case detection were 98% and 100% (-2.0%, 95% CI -4.3 to +0.3). Ultra and Xpert performed equal in detecting RIF-R. INTERPRETATION: Sensitivity of Ultra was superior to that of Xpert in all categories of clinical samples. However, improved sensitivity was associated with a modest reduction in specificity.

Is ozone pre-conditioning effect linked to Nrf2/EpRE activation pathway in vivo? A preliminary result.

The present preliminary study has been focused on verifying whether ozone preconditioning may be linked to Nrf2/EpRE (nuclear factor erythroid 2/electrophile-responsive element) activation pathway in vivo. Healthy volunteers received a total of three Major Auto-Hemotherapy (MAH) treatments, with treatments administered every second day. The amount of blood used for each subject was standardized to the value obtained multiplying the subject׳s body weight by 1.3 in order to ensure the same ozone concentrations for each subject. A parallel group (n=50) age and gender matched was used as reference for the experimental variables related to the oxidative stress parameters. Levels of Nrf2 and oxidative stress index were measured throughout the study. Levels of Nrf2 (P<0.01) in peripheral blood mononuclear cells (PBMC) were found to increase immediately after ozone/oxygen exposure (35µg/ml, prior to reinfusion). This effect was still detected (P<0.05) in total circulating PBMC when measured 30min following reinfusion. After a series of 3 MAH, Nrf2 returned back to the basal level. At the end of the experiment the activities of superoxide dismutase and catalase were increased (P<0.05). These data demonstrate for the first time in vivo the activation of the Nrf2 pathway by a low dose of ozone and the promotion of the feedback mechanism that induces the synthesis of proteins which collectively favors cell survival.

Nebivolol induces, via ß3 adrenergic receptor, lipolysis, uncoupling protein 1, and reduction of lipid droplet size in human adipocytes.

OBJECTIVES: Most ß-blockers may induce weight gain, dysglycemia, and dyslipidemia. Nebivolol is a third-generation ß1-blocker with vasodilating properties mediated by ß3 adrenergic receptors (ß3AR). We investigated whether nebivolol is able to induce ß3AR-mediated lipolysis, uncoupling protein 1 (UCP1), and size-reduction in human adipocytes. METHODS: Human visceral (n = 28) and subcutaneous adipose tissue (n = 26) samples were used to obtain differentiated subcutaneous and visceral preadipocytes. Adipocytes were used to verify the effects of nebivolol onlipolysis, uncoupling protein 1 (UCP1) and other genes of the thermogenic program. RESULTS: Lipolysis was induced by isoproterenol and specific ß3AR agonist, as expected,and also by nebivolol at 100 nmol/l and by its L-enantiomer at 10 nmol/l (P < 0.01). Nebivolol-mediated lipolysis was blocked by SR59230A, a specific ß3AR antagonist, suggesting that nebivolol acts through ß3AR in human adipocytes. Interestingly, in human adipocytes, nebivolol activated UCP1, PPARγ coactivator-1α (PGC-1α) and cytochrome c (CYCS) gene expression in a p38 MAPK-dependent manner. Using propranolol (ß1 and ß2 antagonist) together with nebivolol we showed that the induction of these genes was still present suggesting again ß3AR activation. Moreover, nebivolol significantly reduced the diameter of lipid droplets in cultured adipocytes. CONCLUSION: In summary, nebivolol, through ß3AR, is able to induce lipolysis and promote thermogenic and mitochondrial genes. The induction of lipolysis and the thermogenic program could explain the reduction of lipid droplets size. In conclusion, the lower dysmetabolic effects of nebivolol in humans may depend on its ß3 agonist activity and the consequent induction of thermogenic program in human adipocytes.