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.

Human Campylobacter spp. infections in Italy.

PURPOSE: Campylobacter is a frequent cause of enteric infections with common antimicrobial resistance issues. The most recent reports of campylobacteriosis in Italy include data from 2013 to 2016. We aimed to provide national epidemiological and microbiological data on human Campylobacter infections in Italy during the period 2017-2021. METHODS: Data was collected from 19 Hospitals in 13 Italian Regions. Bacterial identification was performed by mass spectrometry. Antibiograms were determined with Etest or Kirby-Bauer (EUCAST criteria). RESULTS: In total, 5419 isolations of Campylobacter spp. were performed. The most common species were C. jejuni (n = 4535, 83.7%), followed by C. coli (n = 732, 13.5%) and C. fetus (n = 34, 0.6%). The mean age of patients was 34.61 years and 57.1% were males. Outpatients accounted for 54% of the cases detected. Campylobacter were isolated from faeces in 97.3% of cases and in 2.7% from blood. C. fetus was mostly isolated from blood (88.2% of cases). We tested for antimicrobial susceptibility 4627 isolates (85.4%). Resistance to ciprofloxacin and tetracyclines was 75.5% and 54.8%, respectively; resistance to erythromycin was 4.8%; clarithromycin 2% and azithromycin 2%. 50% of C. jejuni and C. coli were resistant to ≥ 2 antibiotics. Over the study period, resistance to ciprofloxacin and tetracyclines significantly decreased (p < 0.005), while resistance to macrolides remained stable. CONCLUSION: Campylobacter resistance to fluoroquinolones and tetracyclines in Italy is decreasing but is still high, while macrolides retain good activity.

Cefiderocol use for the treatment of infections by carbapenem-resistant Gram-negative bacteria: an Italian multicentre real-life experience.

BACKGROUND: Cefiderocol is a novel siderophore cephalosporin with promising activity against most carbapenem-resistant Gram-negative bacteria (CRGNB). However, extensive postmarketing experiences are lacking. This study aimed to analyse the early experience on cefiderocol postmarketing use at three tertiary care hospitals in Italy. METHODS: We retrospectively included patients with infections caused by CRGNB treated with cefiderocol at three Italian tertiary care hospitals from 1 March 2021 to 30 June 2022. A multivariate Cox model was used to identify predictors of 30 day mortality. A propensity score (PS) analysis with inverse probability weighting (IPW) was also performed to compare the treatment effect of cefiderocol monotherapy (CM) versus combination regimens (CCRs). RESULTS: The cohort included 142 patients (72% male, median age 67 years, with 89 cases of Acinetobacter baumannii infection, 22 cases of Klebsiella pneumoniae, 27 cases of Pseudomonas aeruginosa and 4 of other pathogens). The 30 day all-cause mortality was 37% (52/142). We found no association between bacterial species and mortality. In multivariate analysis, a Charlson Comorbidity Index >3 was an independent predictor of mortality (HR 5.02, 95% CI 2.37-10.66, P < 0.001). In contrast, polymicrobial infection (HR 0.41, 95% CI 0.21-0.82, P < 0.05) was associated with lower mortality. There was no significant difference in mortality between patients receiving CM (n = 70) and those receiving a CCR (n = 72) (33% versus 40%, respectively), even when adjusted for IPW-PS (HR 1.11, 95% CI 0.63-1.96, P = 0.71). CONCLUSIONS: Real-life data confirm that cefiderocol is a promising option against carbapenem-resistant Gram-negative infections, even as monotherapy.

Oxazolidinones: mechanisms of resistance and mobile genetic elements involved.

The oxazolidinones (linezolid and tedizolid) are last-resort antimicrobial agents used for the treatment of severe infections in humans caused by MDR Gram-positive bacteria. They bind to the peptidyl transferase centre of the bacterial ribosome inhibiting protein synthesis. Even if the majority of Gram-positive bacteria remain susceptible to oxazolidinones, resistant isolates have been reported worldwide. Apart from mutations, affecting mostly the 23S rDNA genes and selected ribosomal proteins, acquisition of resistance genes (cfr and cfr-like, optrA and poxtA), often associated with mobile genetic elements [such as non-conjugative and conjugative plasmids, transposons, integrative and conjugative elements (ICEs), prophages and translocatable units], plays a critical role in oxazolidinone resistance. In this review, we briefly summarize the current knowledge on oxazolidinone resistance mechanisms and provide an overview on the diversity of the mobile genetic elements carrying oxazolidinone resistance genes in Gram-positive and Gram-negative bacteria.

Occurrence of a plasmid co-carrying cfr(D) and poxtA2 linezolid resistance genes in Enterococcus faecalis and Enterococcus casseliflavus from porcine manure, Italy.

OBJECTIVES: To investigate the genetic elements and the transferability of linezolid resistance genes in three enterococci co-carrying cfr(D) and poxtA2 isolates from manure of a swine farm in central Italy. METHODS: Two Enterococcus faecalis isolates and one Enterococcus casseliflavus isolate carrying both cfr(D) and poxtA genes were tested for their susceptibility to florfenicol, chloramphenicol, linezolid, tedizolid, tetracycline and vancomycin. Linezolid resistance genes transfer (filter mating), localization (S1-PFGE/hybridization), genetic elements and relatedness between isolates (WGS) were analysed. RESULTS: Two E. faecalis isolates and one E. casseliflavus isolate carried the cfr(D) gene and the recently described poxtA2 variant. In the three enterococci, cfr(D) and poxtA2 were co-located on a 33 480 bp plasmid, pV386, 95%-100% identical (coverage 84%) to the Tn6349 transposon of Staphylococcus aureus AOUC-0915. In all isolates, both genes also showed a chromosomal location. Same sequence identities were found from the comparison with currently known poxtA2 genetic elements. In the plasmid pV386, poxtA2 gene was not bounded by two IS1216, as described in pIB-BOL, but closely associated to the cfr(D) and fexA genes. pV386 was always transferred by filter mating to Enterococcus faecium 64/3 recipient. CONCLUSIONS: The occurrence of the pV386 plasmid in E. faecalis and E. casseliflavus from swine manure is of great concern and highlights the need for control measures to contain its spread to other enterococcal species.

Linezolid-resistant Enterococcus gallinarum isolate of swine origin carrying cfr, optrA and poxtA genes.

OBJECTIVES: To characterize a linezolid-resistant Enterococcus gallinarum isolate of porcine origin co-carrying cfr, optrA and poxtA genes. METHODS: The genome was sequenced using the Illumina and Nanopore platforms. The presence of circular intermediates was examined by inverse PCR. Transferability of oxazolidinone resistance genes was investigated by transformation and conjugation. RESULTS: Two plasmids, the cfr- and optrA-carrying pEgFS4-1 (35 kb) and the poxtA-harbouring pEgFS4-2 (38 kb), were identified. pEgFS4-1 disclosed a distinctive mosaic structure with two cargo regions bounded by identical IS1216 elements interpolated into a backbone related to that of Enterococcus faecium vanA-containing pVEF2. The first cargo region included the cfr and optrA contexts, whereas the second one carried a Tn554 remnant and the lnu(A) gene. Both regions were able to excise in circular form as a unique translocable unit. pEgFS4-2 plasmid was 99% identical to a not fully described E. faecium pSBC1 plasmid. The poxtA environment, flanked by IS1216, was proved to be unstable. pEgFS4-2 also exhibited another cargo region containing the tet(M)-tet(L) genes arranged in tandem and its circular form was detected. Transformation and conjugation experiments failed to demonstrate the transferability of both plasmids to enterococcal recipients. Both plasmids persisted in the absence of selective pressure. CONCLUSIONS: To the best of our knowledge, this is the first description of a linezolid-resistant E. gallinarum isolate of swine origin carrying cfr, optrA and poxtA genes. The co-presence of three linezolid resistance determinants in an intrinsically vancomycin-resistant enterococcal species is cause of concern.

Candidemia in Internal Medicine: Facing the New Challenge.

Candidemia is an alarming problem in critically ill patients including those admitted in Internal Medicine Wards (IMWs). Here, we analyzed all cases of candidemia in adult patients hospitalized over nine years (2010-2018) in IMWs of a 980-bedded University Hospital of Ancona, Italy. During the study period, 218/505 (43%) episodes of candidemia occurred in IMWs patients. The cumulative incidence was 2.5/1000 hospital admission and increased significantly over time (p = 0.013). Patients were predominantly male, with a median age of 68 years. Cardiovascular diseases and solid tumors were the most frequent comorbidities. Candida albicans accounted for 51% of the cases, followed by C. parapsilosis (25%), C. tropicalis (9%) and C. glabrata (7%). Thirty-day mortality was 28% and did not increased significantly over time. By multivariate logistic regression analysis, the presence of neutropenia (OR 7.247 [CI95% 1,368-38,400; p = 0.020]), pneumonia (OR 2.323 [CI95% 1,105-4,884; p = 0.026]), and being infected with C. albicans (OR 2.642 [95% CI 1,223-5,708; p = 0.013) emerged as independent predictors of mortality. The type of antifungal therapy did not influence the outcome. Overall, these data indicate that patients admitted to IMWs are increasingly at higher risk of developing candidemia. Mortality rate remains high and significantly associated with both microbiologic- and host-related factors.

Anaerobic bloodstream infections in Italy (ITANAEROBY): A 5-year retrospective nationwide survey.

INTRODUCTION: A lack of updated data on the burden and profile of anaerobic bloodstream infections (ABIs) exists. We assessed the incidence of ABIs and trends in antimicrobial resistance in anaerobes isolated from blood in Italy. MATERIAL AND METHODS: We conducted a retrospective study on 17 Italian hospitals (2016-2020). Anaerobes isolated from blood culture and their in vitro susceptibility profiles (EUCAST-interpreted) were registered and analyzed. RESULTS: A total of 1960 ABIs were identified. The mean age of ABIs patients was 68.6 ± 18.5 years, 57.6% were males. The overall incidence rate of ABIs was 1.01 per 10.000 patient-days. Forty-seven% of ABIs occurred in medical wards, 17% in ICUs, 14% in surgical wards, 7% in hemato-oncology, 14% in outpatients. The three most common anti-anaerobic tested drugs were metronidazole (92%), clindamycin (89%) and amoxicillin/clavulanate (83%). The three most common isolated anaerobes were Bacteroides fragilis (n = 529), Cutibacterium acnes (n = 262) and Clostridium perfringens (n = 134). The lowest resistance rate (1.5%) was to carbapenems, whereas the highest rate (51%) was to penicillin. Clindamycin resistance was >20% for Bacteroides spp., Prevotella spp. and Clostridium spp. Metronidazole resistance was 9.2% after excluding C. acnes and Actinomyces spp. Bacteroides spp. showed an increased prevalence of clindamycin resistance through the study period: 19% in 2016, 33% in 2020 (p ≤ 0.001). CONCLUSIONS: Our data provide a comprehensive overview of the epidemiology of ABIs in Italy, filling a gap that has existed since 1995. Caution is needed when clindamycin is used as empirical anti-anaerobic drug.

Linezolid Resistance Genes in Enterococci Isolated from Sediment and Zooplankton in Two Italian Coastal Areas.

Linezolid is a last-resort antibiotic for the treatment of severe infections caused by multidrug-resistant Gram-positive organisms; although linezolid resistance remains uncommon, the number of linezolid-resistant enterococci has increased in recent years due to worldwide spread of acquired resistance genes (cfr, optrA, and poxtA) in clinical, animal, and environmental settings. In this study, we investigated the occurrence of linezolid-resistant enterococci in marine samples from two coastal areas in Italy. Isolates grown on florfenicol-supplemented Slanetz-Bartley agar plates were investigated for their carriage of optrA, poxtA, and cfr genes; optrA was found in one Enterococcus faecalis isolate, poxtA was found in three Enterococcus faecium isolates and two Enterococcus hirae isolates, and cfr was not found. Two of the three poxtA-carrying E. faecium isolates and the two E. hirae isolates showed related pulsed-field gel electrophoresis (PFGE) profiles. Two E. faecium isolates belonged to the new sequence type 1710, which clustered in clonal complex 94, encompassing nosocomial strains. S1 PFGE/hybridization assays showed a double (chromosome and plasmid) location of poxtA and a plasmid location of optrA Whole-genome sequencing revealed that poxtA was contained in a Tn6657-like element carried by two plasmids (pEfm-EF3 and pEh-GE2) of similar size, found in different species, and that poxtA was flanked by two copies of IS1216 in both plasmids. In mating experiments, all but one strain (E. faecalis EN3) were able to transfer the poxtA gene to E. faecium 64/3. The occurrence of linezolid resistance genes in enterococci from marine samples is of great concern and highlights the need to improve practices aimed at limiting the transmission of linezolid-resistant strains to humans from environmental reservoirs.IMPORTANCE Linezolid is one of the few antimicrobials available to treat severe infections due to drug-resistant Gram-positive bacteria; therefore, the emergence of linezolid-resistant enterococci carrying transferable resistance determinants is of great concern for public health. Linezolid resistance genes (cfr, optrA, and poxtA), often plasmid located, can be transmitted via horizontal gene transfer and have the potential to spread globally. This study highlights the detection of enterococci carrying linezolid resistance genes from sediment and zooplankton samples from two coastal urban areas in Italy. The presence of clinically relevant resistant bacteria, such as linezolid-resistant enterococci, in marine environments could reflect their spillover from human and/or animal reservoirs and could indicate that coastal seawaters also might represent a source of these resistance genes.

Human leptospirosis in the Marche region: Over 10 years of surveillance.

We conducted a 10 years' retrospective study in 347 symptomatic individuals to assess the regional distribution of leptospirosis. A total of 173 individuals were diagnosed positive (49.8%): 11.5% were found positive to Leptospira by microscopic agglutination test positive, whereas 38.3% were found positive by microscopy analysis. The maximum peak of leptospirosis was reached in 2017 (n = 32). The most common serovars were Icterohaemorrhagiae and Poi.

New Evidence and Insights on Dalbavancin and Wound Healing in a Mouse Model of Skin Infection.

Dalbavancin is an effective antibiotic that is widely used to treat skin infection. Our aim was to determine the effect of dalbavancin administration on wound healing compared to that of vancomycin and to elucidate if epidermal growth factor receptor (EGFR), matrix metalloproteinase 1 (MMP-1), MMP-9, and vascular endothelial growth factor (VEGF) could be involved in its therapeutic mechanism. A mouse model of methicillin-resistant Staphylococcus aureus (MRSA) skin infection was established. Mice were treated daily with vancomycin (10 mg/kg) and weekly with dalbavancin at day 1 (20 mg/kg) and day 8 (10 mg/kg). After 14 days, wounds were excised, and bacterial counts were performed. Wound healing was assessed by histological and immunohistochemical staining, followed by protein extraction and immunoblotting. Our microbiological results confirmed that both dalbavancin and vancomycin are effective in reducing the bacterial load in wounds. The dalbavancin group showed a strong effect compared with infected untreated animals and the vancomycin-treated group. The wounds treated with dalbavancin showed robust epidermal coverage with reconstitution of the regular and keratinized epidermal lining and well-organized granulation tissue with numerous blood vessels, although slightly less than that in the uninfected group. While in the vancomycin-treated group the epithelium appeared, in general, still hypertrophic, the granulation tissue appeared even less organized. We observed elevated EGFR and VEGF expression in both treated groups, although it was higher in dalbavancin-treated mice. MMP-1 and MMP-9 were decreased in uninfected tissue and in both treated tissues compared with untreated infected wounds. This study showed faster healing with dalbavancin treatment that might be associated with higher EGFR and VEGF levels.

Characterization of a new transferable MDR plasmid carrying the pbp5 gene from a clade B commensal Enterococcus faecium.

OBJECTIVES: To evaluate the transferability of antibiotic resistance from an MDR clade B Enterococcus faecium and to characterize the genetic elements involved. METHODS: The erm(B)-positive strain E. faecium 37BA (donor) and strains E. faecium 64/3 and Listeria welshimeri 11857RF (recipients) were used in mating experiments. Donors and transconjugants were characterized using MIC assays, PFGE, Southern blotting and hybridization, quantitative RT-PCR (RT-qPCR), next-generation sequencing and PCR mapping. RESULTS: One E. faecium and one L. welshimeri transconjugant were selected for in-depth investigation. Both acquired an ∼40 kb plasmid carrying erm(B). An additional plasmid of ∼200 kb, encoding the full conjugation machinery, was detected in the donor and in the E. faecium transconjugant. Next-generation sequencing revealed a new 40 396 bp plasmid that was designated pEf37BA; it contained 10 antibiotic resistance genes, tet(M), tet(L), erm(B), aadE, sat4, aphA, spw, lsa(E), lnu(B) and pbp5, resulting from the recombination of pM7M2 of E. faecium with an MDR chromosomal region of Erysipelothrix rhusiopathiae. A pbp5-carrying circular form was also detected. The PBP5 amino acid sequence differed from the C46 variant by two mutations (S39T and D644N). Its expression was documented in both transconjugants. pEf37BA persisted in the absence of selective pressure. CONCLUSIONS: The MDR clade B E. faecium plasmid, deriving from the recombination of two different resistance regions, carried a pbp5 element and was transferable to different bacterial species. This finding further documents the dissemination of ampicillin resistance among community-associated E. faecium and the key role of commensal strains in the spread of antibiotic resistance.

Characterization of Tn6349, a novel mosaic transposon carrying poxtA, cfr and other resistance determinants, inserted in the chromosome of an ST5-MRSA-II strain of clinical origin.

OBJECTIVES: To characterize the genetic element carrying the poxtA oxazolidinone resistance gene found in the poxtA index strain Staphylococcus aureus AOUC-0915 isolated from a cystic fibrosis patient. METHODS: The genetic context of poxtA was investigated by bioinformatics analysis of WGS data of strain AOUC-0915, followed by PCR and confirmatory Sanger sequencing for repetitive regions. Conjugation and electrotransformation experiments were carried out to assess horizontal transferability using S. aureus and Enterococcus faecalis recipients. Production of phage particles was evaluated by PCR using DNA preparations obtained after phage induction. Excision of the transposon carrying poxtA was evaluated by inverse PCR experiments for detection of circular intermediates. RESULTS: poxtA was found to be associated with a 48 kb composite transposon of original structure, named Tn6349, inserted into a φN315-like prophage. The transposon was bounded by two IS1216 insertion sequences, carried several resistance genes [erm(B), cfr, poxtA and fexB] and exhibited a mosaic structure made by a derivative of plasmid pE35048-oc (previously described in an Enterococcus faecium clinical isolate) and Tn6657, a novel composite transposon carrying the poxtA and fexB genes. Excision ability of Tn6349 as a circular intermediate was demonstrated. Transferability of Tn6349 or modules thereof to S. aureus or E. faecalis by either conjugation or electrotransformation was not detected. Induction of the φN315-like prophage carrying Tn6349 was not observed. CONCLUSIONS: This study describes the structure of Tn6349, a novel composite transposon carrying several resistance determinants to anti-ribosomal drugs, including cfr and poxtA, from an oxazolidinone-resistant MRSA strain. Analysis of Tn6349 revealed a modular structure that could favour the mobilization of its resistance determinants.

In vitro activity of Protegrin-1, alone and in combination with clinically useful antibiotics, against Acinetobacter baumannii strains isolated from surgical wounds.

In the past few years the increasing incidence of hospital infections with Acinetobacter baumannii, especially in immunocompromised patients, and its proneness to develop multidrug resistance have been raising considerable concern. This study examines the antimicrobial and antibiofilm activity of protegrin 1 (PG-1), an antimicrobial peptide from porcine leukocytes, against A. baumannii strains isolated from surgical wounds. PG-1 was tested both alone and combined with the antibiotics commonly used in clinical settings. Its antimicrobial activity was evaluated by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), checkerboard assays, and time-kill experiments. Its effects on biofilm inhibition/eradication were tested with crystal violet staining. The strains were grown in subinhibitory or increasing PG-1 concentrations to test the development of resistance. Mammalian cell toxicity was tested by XTT assays. PG-1 MICs and MBCs ranged from 2 to 8 µg/ml. PG-1 was most active and demonstrated a synergistic interaction with colistin, a last resort antibiotic. Interestingly, antagonism was never observed. In time-kill experiments, incubation with 2 × MIC for 30 min suppressed all viable cells. PG-1 did not select resistant strains and showed a limited effect on cell viability, but it did exert a strong activity against multidrug-resistant A. baumannii. In contrast, in our experimental conditions it had no effect on biofilm inhibition/eradication. PG-1 thus seems to be a promising antimicrobial agent against multidrug-resistant Gram-negative infections.

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.

Clinical and epidemiological characteristics of KPC-producing Klebsiella pneumoniae from bloodstream infections in a tertiary referral center in Italy.

BACKGROUND: Bloodstream infections (BSI) due to Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) have become an important problem and they are associated with a high mortality rate. The aim of our study was to evaluate the clinical and epidemiological characteristics of KPC-Kp from BSIs. METHODS: In this retrospective cohort study, conducted in a tertiary referral center in Italy, 112 patients with KPC-Kp BSIs diagnosed between February 2011 and December 2015 were identified. We evaluated the mortality at 30 days from the first positive blood culture. Survivor and non-survivor subgroups were compared to identify predictors of mortality. RESULTS: The overall crude mortality was 35%. APACHE II score ≥ 15, septic shock at BSI onset, immunosuppressive therapy during the 30 days before the BSI onset, and the lack of a combination therapy with at least 2 active drugs emerged as independent predictors of mortality. Excluding patients with inadequate therapy, the mortality decreased to 25% while an APACHE II score ≥ 15 and the presence of septic shock remained independently associated with a negative outcome. Two different pulsotypes were identified: pulsotype A belonged to ST512 and carried KPC-3 and pulsotype B belonged to ST307 and carried KPC-2. CONCLUSIONS: This study confirmed a high mortality rate of KPC-Kp BSIs. The outcome is heavily influenced by the patient's clinical conditions. A therapeutic approach including a combination with at least two active drugs in vitro can improve the prognosis, unless patients received an appropriate therapy.

Characterisation of candidemia in patients with recent surgery: A 7-year experience.

Candidemia can complicate major surgical procedures. However, literature data are scanty on this topic. In this study, we evaluated the epidemiology, clinical and microbiologic characteristics and outcome of candidemia in adult patients with recent surgery hospitalised in a single University Hospital in Central Italy from 2010 to 2016. Of the 304 episodes of candidemia, 160 (53%) occurred in surgical patients (SPs) while the remaining 144 (47%) in patients without history of recent surgery (non-SPs). Although either underlying chronic comorbidities (ie haematological malignancies, neurological and gastrointestinal diseases) or acute complications (ie pneumonia and septic shock) were less likely to occur in SPs than in non-SPs, 30-day mortality did not differ between groups being 38% and 42%, respectively. The specific risk factors significantly more common in SPs who died within 30 days were as follows: male gender, older age, being hospitalised in ICU rather than in other wards, having a higher Charlson's score, undergoing previous invasive procedures, haemodialysis, the presence of pneumonia, septic shock, acute kidney failure and the type of surgery. In particular, either gastrointestinal or cardiovascular surgeries were characterised by the highest mortality rates. Multivariate analysis showed that the occurrence of septic shock (HR 10.3131 [CI95% 1.176-90.466; P = .035] and ICU stay (HR 2.016 [CI95% 1.178-3.448; P = .011] was independently associated with higher mortality in SPs. Overall, these data show that candidemia in SPs is characterised by significant mortality and distinctive features.

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.

Characterization of poxtA, a novel phenicol-oxazolidinone-tetracycline resistance gene from an MRSA of clinical origin.

Objectives: To characterize a novel phenicol-oxazolidinone-tetracycline resistance gene, named poxtA, identified in a previously described MRSA strain that was highly resistant to linezolid and also carried the cfr gene. Methods: The poxtA gene was identified by bioinformatic analysis of the whole genome sequence of Staphylococcus aureus AOUC-0915. The poxtA gene was cloned in a shuttle plasmid vector and expressed in Escherichia coli, S. aureus and Enterococcus faecalis to investigate the protein function. Comparative sequence analyses at the protein and genetic levels were carried out using standard procedures. Results: The poxtA gene encodes a protein that is 32% identical to OptrA and exhibits structural features typical of the F lineage of the ATP-binding cassette (ABC) protein superfamily that cause antibiotic resistance by ribosomal protection. Expression of poxtA in E. coli, S. aureus and E. faecalis was able to decrease susceptibility to phenicols, oxazolidinones and tetracyclines. A database search identified the presence of poxtA in E. faecalis, Enterococcus faecium and Pediococcus acidilactici strains, mostly of animal origin, and revealed the presence of poxtA homologues in the genomes of some Clostridiales. Analysis of the genetic context revealed that poxtA was located in a composite transposon-like structure containing two IS1216 elements. Conclusions: A novel resistance gene, named poxtA, encoding a protein of the antibiotic resistance (ARE) ABC-F lineage, was identified in the genome of an MRSA of clinical origin. PoxtA can confer decreased susceptibility to phenicols, oxazolidinones and tetracyclines and is associated with a putative mobile element that could contribute to its horizontal dissemination.