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.

Clinical and microbiological features of ceftolozane/tazobactam-resistant Pseudomonas aeruginosa isolates in a university hospital in central Italy.

OBJECTIVES: Ceftolozane/tazobactam (C/T) is a novel cephalosporin and ß-lactamase inhibitor combination with great activity against Pseudomonas aeruginosa. To assess P. aeruginosa susceptibility to C/T, a surveillance study was conducted from October 2018 to March 2019 at the University Hospital 'Ospedali Riuniti' in Ancona, Italy. METHODS: Minimum inhibitory concentrations (MICs) to C/T were determined by Etest strip. Resistant isolates were characterized by phenotypic (broth microdilution antimicrobial susceptibility testing and modified Carbapenem Inactivation Method [mCIM]) and genotypic (Polymerase Chain Reaction [PCR], Pulsed Field Gel Electrophoresis [PFGE], and whole-genome sequencing [WGS]) methods. Clinical variables of patients infected by C/T-resistant P. aeruginosa were collected from medical records. RESULTS: Fifteen of 317 P. aeruginosa collected showed resistance to C/T (4.7%). Ten strains demonstrated carbapenemase activity by mCIM method, and PCR confirmed that eight strains harbored a blaVIM gene while the other two were positive for blaIMP. Additionally, three isolates carried acquired extended spectrum ß-lactamase genes (two isolates carried blaPER and one carried blaGES). Eight strains were strictly related by PFGE and WGS analysis confirmed that they belonged to sequence type (ST)111. The other STs found were ST175 (two isolates), ST235 (two isolates), ST70 (one isolate), ST621 (one isolate), and the new ST3354 (one isolate). Most patients had received previous antibiotic therapies, carried invasive devices, and experienced prolonged hospitalization. CONCLUSION: This study demonstrated the presence of C/T-resistant P. aeruginosa isolates in a regional hospital carrying a number of resistance mechanisms acquired by different high-risk clones.

Ceftazidime-Avibactam for the Treatment of Multidrug-Resistant Pathogens: A Retrospective, Single Center Study.

Background: Ceftazidime/avibactam is a new cephalosporin/beta-lactamase inhibitor combination approved in 2015 by the FDA for the treatment of complicated intra-abdominal and urinary tract infection, hospital-acquired pneumoniae and Gram-negative infections with limited treatment options. Methods: In this retrospective study, we evaluate the efficacy of ceftazidime/avibactam treatment in 81 patients with Gram-negative infection treated in our center from January 2018 to December 2019. The outcome evaluated was 30-days survival or relapse of infection after the first positive blood culture. Results: the majority of patients were 56 male (69%), with median age of 67. Charlson's Comorbidity Index was >3 in 58 patients. In total, 46% of the patients were admitted into the medical unit, 41% in the ICU, and 14% in the surgical ward. Of the patients, 78% had nosocomial infections, and 22% had healthcare-related infections. The clinical failure rate was 35%: 13 patients died within 30 days from the onset of infection. The outcome was influenced by the clinical condition of the patients: solid organ transplantation (p = 0.003) emerged as an independent predictor of mortality; non-survival patients most frequently had pneumonia (p = 0.009) or mechanical ventilation (p = 0.049). Conclusion: Ceftazidime−avibactam showed high efficacy in infections caused by MDR Gram-negative pathogens with limited therapeutic options.

Bloodstream infections in the COVID-19 era: results from an Italian multi-centre study.

BACKGROUND: Correlation between coronavirus disease 2019 (COVID-19) and superinfections has been investigated, but remains to be fully assessed. This multi-centre study reports the impact of the pandemic on bloodstream infections (BSIs). METHODS: This study included all patients with BSIs admitted to four Italian hospitals between 1 January and 30 June 2020. Clinical, demographic and microbiologic data were compared with data for patients hospitalized during the same period in 2019. RESULTS: Among 26,012 patients admitted between 1 January and 30 June 2020, 1182 had COVID-19. Among the patients with COVID-19, 107 BSIs were observed, with an incidence rate of 8.19 episodes per 1000 patient-days. The incidence of BSI was significantly higher in these patients compared with patients without COVID-19 (2.72/1000 patient-days) and patients admitted in 2019 (2.76/1000 patient-days). In comparison with patients without COVID-19, BSI onset in patients with COVID-19 was delayed during the course of hospitalization (16.0 vs 5 days, respectively). Thirty-day mortality among patients with COVID-19 was 40.2%, which was significantly higher compared with patients without COVID-19 (23.7%). BSIs in patients with COVID-19 were frequently caused by multi-drug-resistant pathogens, which were often centre-dependent. CONCLUSIONS: BSIs are a common secondary infection in patients with COVID-19, characterized by increased risk during hospitalization and potentially burdened with high mortality.

Use of Dalbavancin in Skin, Bone and Joint Infections: A Real-Life Experience in an Italian Center.

Dalbavancin is a lipoglycopeptide approved for the treatment of acute bacterial skin and skin structure infections (ABSSSI). The aim of the study was to evaluate the efficacy and safety in all patients who received at least one administration of dalbavancin. METHODS: We carried out a retrospective study of the use of dalbavancin in 55 patients at the Azienda Ospedaliera Ospedali Riuniti Umberto I (Ancona, Italy) from February 2017 to May 2020 and compared "on label" and "off label" use of dalbavancin in ABSSSI and non-ABSSSI. RESULTS: A total of 55 patients were included in the study. The median age was 61 years; 51% had ABSSSI; 24% had prosthetic joint infections, and 14% had osteomyelitis. A total of 53% received a single 1500 mg infusion of dalbavancin, and 18% received a second dose 14 days later; 24% of patients received further doses at 14-day intervals. In 91% of cases, patients achieved clinical objectives with dalbavancin: 96% of patients with ABSSSI and 69% of those with prosthetic joint infections. CONCLUSIONS: Dalbavancin was shown to have an excellent tolerability profile and to be a highly successful therapeutic approach even in those cases treated "off-label".

In vitro susceptibility of dermatophytes to conventional and alternative antifungal agents.

The minimum inhibitory concentrations (MICs), the minimal fungicidal concentrations (MFCs), the fungal biomass (FB) and hyphal viability employing the dye 3-4,5 dimethyl- 2-thiazolyl- 2,5- diphenyl- 2H tetrazolium bromide (MTT) were used to compare the in vitro effects of fluconazole (FLU) with those of the N-terminal palmitoyl-lipidated peptide, Pal-Lys-Lys-NH(2) (PAL), and a tea tree oil component, gamma-Terpinene (TER), against several clinical isolates of Microsporum canis and Trichophyton rubrum. In general, FLU and PAL MICs were significantly lower than those observed with TER, while no differences in the three drugs were found in the MFCs. However, they were from two to 16-times higher than their respective MICs. FB of M. canis treated with either FLU or PAL, but not with TER, was significantly reduced over untreated controls. Only PAL and TER, in a medium-dependent fashion, but not FLU, reduced the FB of T. rubrum. Finally, PAL was found to be significantly more active than FLU at reducing the hyphal viability against both genera of dermatophytes. This study shows that PAL exerts an in vitro activity against dermatophytes at least similar to that observed with FLU and suggests that this compound might be a promising candidate in the treatment of infections due to dermatophytes.

Efficacy of the combination of tachyplesin III and clarithromycin in rat models of Escherichia coli sepsis.

We investigated the efficacy of tachyplesin III and clarithromycin in two experimental rat models of severe gram-negative bacterial infections. Adult male Wistar rats were given either (i) an intraperitoneal injection of 1 mg/kg Escherichia coli 0111:B4 lipopolysaccharide or (ii) 2 x 10(10) CFU of E. coli ATCC 25922. For each model, the animals received isotonic sodium chloride solution, 1 mg/kg tachyplesin III, 50 mg/kg clarithromycin, or 1 mg/kg tachyplesin III combined with 50 mg/kg clarithromycin intraperitoneally. Lethality, bacterial growth in the blood and peritoneum, and the concentrations of endotoxin and tumor necrosis factor alpha (TNF-alpha) in plasma were evaluated. All the compounds reduced the lethality of the infections compared to that for the controls. Tachyplesin III exerted a strong antimicrobial activity and achieved a significant reduction of endotoxin and TNF-alpha concentrations in plasma compared to those of the control and clarithromycin-treated groups. Clarithromycin exhibited no antimicrobial activity but had a good impact on endotoxin and TNF-alpha plasma concentrations. A combination of tachyplesin III and clarithromycin resulted in significant reductions in bacterial counts and proved to be the most-effective treatment in reducing all variables measured.

Protective effects of the combination of alpha-helical antimicrobial peptides and rifampicin in three rat models of Pseudomonas aeruginosa infection.

INTRODUCTION: An experimental study has been performed to compare the in vitro activity and the in vivo efficacy of magainin II and cecropin A with or without rifampicin against control and multidrug-resistant Pseudomonas aeruginosa strains. METHODS: In vitro experiments included MIC determinations and synergy studies. For in vivo studies, animals were given an intraperitoneal injection of P. aeruginosa lipopolysaccharide, P. aeruginosa ATCC 27853 and one clinical multiresistant P. aeruginosa strain. Groups of animals received intravenously isotonic sodium chloride solution, 10 mg/kg rifampicin, 1 mg/kg magainin II or 1 mg/kg cecropin A. Two groups of animals received a combined treatment with magainin II + rifampicin or cecropin A + rifampicin at the same dosages as the singly treated groups. In addition, a further group was treated with tazobactam/piperacillin (120 mg/kg). Lethality, bacterial growth in blood and peritoneum, and endotoxin and TNF-alpha concentrations in plasma were evaluated. RESULTS: Combinations of alpha-helical antimicrobial peptides showed in vitro synergistic interaction. Magainin II and cecropin A exerted strong antimicrobial activity and achieved a significant reduction in plasma endotoxin and TNF-alpha concentrations when compared with control and rifampicin-treated groups. Rifampicin exhibited no anti-P. aeruginosa activity and good substantial impact on endotoxin and TNF-alpha plasma concentrations. Combined treatment groups had significant reductions in bacterial count, positive blood cultures and mortality rates when compared with singly treated and control groups. CONCLUSIONS: Our results highlight the potential usefulness of these combinations that provide future therapeutic alternatives in P. aeruginosa infections.

Spread of colistin resistance gene mcr-1 in Italy: characterization of the mcr-1.2 allelic variant in a colistin-resistant blood isolate of Escherichia coli.

mcr-1.2, an allelic variant of the transferable colistin resistance gene mcr-1, was characterized in a colistin-resistant blood isolate of Escherichia coli. It was harbored by an IncX4-type plasmid (33,293 bp). Despite its low prevalence, the potentially worrying spread of the mcr-1 gene, particularly its mcr-1.2 variant, in Italy requires increasing surveillance.

Antiretroviral therapy management and rationalisation of available resources.

The treatment of HIV disease has led to a new division of management costs by shifting most of the necessary resources from inpatient treatment to outpatient management. Among the initiatives aimed at rationalising the resources available, we compared efficacy, tolerability and pharmacoeconomic impact of different regimes of antiretroviral therapy (ART). The survey covered the first 50 patients, clinically stable and with good viro-immunological response, who switched in June 2012 from an ART based on the triple combination of tenofovir (TDF), emtricitabine (FTC) and a protease inhibitor boosted with ritonavir (PI/r) or a non-nucleoside reverse transcriptase inhibitor (NNRTI), to a treatment based on abacavir (ABC), lamivudine (3TC) and a PI/r or NNRTI. Of the 50 patients who operated the switch, 39 replaced a PI with nevirapine (NVP), for which the largest group of patients was treated with ABC + 3TC + NVP. On 31 May 2015, all patients completed the observation period of 96 weeks, with a mean observation period of 132 weeks and clinical-laboratory checks every four months. Laboratory analysis revealed an optimal maintenance of viral suppression and absolute and relative number of CD4 + lymphocytes and improving trend of creatinine, proteinuria, serum phosphate and bone alkaline phosphatase. There was a variable effect on lipids, with a drop in triglycerides associated with a modest increase in total cholesterol. Much of the HIV-positive population reporting to our hospitals (>50%) comprises individuals who have for years been in stable viraemic suppression, making a satisfactory immune recovery while in good overall clinical condition. This type of patient was the target of the present survey. At the end of 96 weeks of observation the new regimes were well tolerated and did not lead to viro-immunological or clinical deterioration. Pharmacoeconomic analysis showed better containment of the overall costs. No patient needed to be hospitalised during the observation period.