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.

Evaluation of antibiofilm activity of cefiderocol alone and in combination with imipenem against Pseudomonas aeruginosa.

OBJECTIVES: The main aim of this study was to evaluate the antibiofilm activity of cefiderocol alone and in combination with imipenem vs. sessile cells of Pseudomonas aeruginosa, assessing a potential synergistic bactericidal effect. METHODS: Ten P. aeruginosa clinical isolates from infected implants and bloodstream were included in the study. Cefiderocol was tested alone and in combination with imipenem on 24-h-old P. aeruginosa biofilm formed on porous glass beads. For each antibiotic formulation, minimum bactericidal biofilm concentration (MBBC), defined as the lowest concentration that determined a reduction of at least 3 log10 CFU/mL compared with the untreated control, was evaluated. Scanning electron microscopy (SEM) was used to investigate the biofilm of P. aeruginosa treated with cefiderocol, imipenem, or their combination. RESULTS: Cefiderocol and imipenem were tested alone on P. aeruginosa biofilm and a reasonable reduction in the number of viable cells was observed, especially at high drug concentrations tested. The synergistic effect of cefiderocol in combination with imipenem was evaluated for five selected isolates. Cotreatment with the two drugs led to a remarkable reduction of cell viability by resulting in synergistic bactericidal activity in all tested strains and in synergistic eradicating activity in only one isolate. SEM analysis revealed that, in cefiderocol-treated biofilm, bacterial cells became more elongated than in the untreated control, forming filaments in which bacterial division seems to be inhibited. CONCLUSIONS: Cefiderocol exhibited an encouraging antibiofilm activity against tested strains, representing a valid option for the treatment of P. aeruginosa biofilm-associated infections, especially when administered in combination with imipenem.

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.

Prevalence and Clinical Consequences of Colistin Heteroresistance and Evolution into Full Resistance in Carbapenem-Resistant Acinetobacter baumannii.

Colistin heteroresistance (HR) refers to a bacterial population comprised of several subpopulations with different levels of resistance to colistin. In this study, we discuss the classic form of HR, in which a resistant subpopulation exists within a predominantly susceptible population. We investigated the prevalence of colistin HR and its evolution into full resistance among 173 clinical carbapenem-resistant Acinetobacter baumannii isolates and examined the effect of HR on clinical outcomes. To determine HR, we performed population analysis profiling. Our results showed a high prevalence of HR (67.1%). To examine evolution of HR strains into full resistance, the HR strains were grown in colistin-containing broth, transferred onto colistin-containing plates, and colonies on these plates were transferred into colistin-free broth. Many of the HR strains (80.2%) evolved into full resistance, 17.2% reverted to HR, and 2.6% were borderline. We used logistic regression to compare 14-day clinical failure and 14-day mortality between patients infected by HR versus susceptible non-HR carbapenem-resistant A. baumannii. In the subgroup of patients with bacteremia, HR was significantly associated with 14-day mortality. IMPORTANCE To our knowledge, this is the first large-scale study to report on HR in Gram-negative bacteria. We described the prevalence of colistin HR in a large sample of carbapenem-resistant A. baumannii isolates, the evolution of many colistin HR isolates to a resistant phenotype following colistin exposure and withdrawal, and the clinical consequences of colistin HR. We found a high prevalence of HR among clinical carbapenem-resistant A. baumannii isolates; most evolved into a resistant phenotype following colistin exposure and withdrawal. In patients treated with colistin, evolution of HR A. baumannii into full resistance could lead to higher rates of treatment failure and contribute to the reservoir of colistin-resistant pathogens in health care settings.

Decolonization of drug-resistant Enterobacteriaceae carriers: A scoping review of the literature.

The ESCMID-EUCIC guideline on decolonization of multidrug-resistant Gram-negative bacteria carriers does not recommend routine decolonization and highlights the necessity of well-powered and designed randomized clinical trials. Based on this limited evidence, we decided to conduct a scoping review with the aim of describing and discussing the last published studies investigating the efficacy and safety of decolonization therapies in drug-resistant Enterobacteriaceae carriers. Studies published in PubMed from January 1, 2017 to December 28, 2021 were retrieved. A PICO (population, intervention, comparator, outcome) framework was used for article selection as follows: Population defined as any patient of any age in any setting with screening sample yielding for drug-resistant Enterobacteriaceae; Intervention defined as any decolonization; Controls defined as patients receiving no intervention (spontaneous decolonization) or a different decolonization therapy; Outcomes defined as a microbiological, clinical, epidemiological and adverse event. A total of 679 records were initially identified, of which 647 were excluded because they were not related to decolonization therapies. Other 18 records were excluded because not related to our aims, target bacteria, or study design. A total of 12 clinical studies were included, of which 4 were randomized clinical trials and 8 were non-randomized studies. The majority of studies evaluated selective decontamination of the digestive tract or selective oropharyngeal decontamination regimens. Selected studies were characterized by high heterogeneity. Further high-quality studies with proper design and sample size calculation are warranted.

Corrigendum to "Effects of adding L-arginine orally to standard therapy in patients with COVID-19: A randomized, double-blind, placebo-controlled, parallel-group trial. Results of the first interim analysis."

[This corrects the article DOI: 10.1016/j.eclinm.2021.101125.].

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.

Large-scale WGS of carbapenem-resistant Acinetobacter baumannii isolates reveals patterns of dissemination of ST clades associated with antibiotic resistance.

OBJECTIVES: To describe the population genetics and antibiotic resistance gene distribution of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates causing infections in three Mediterranean countries. METHODS: Isolates were collected during the 2013-17 AIDA clinical trial in six hospitals in Israel, Greece and Italy. WGS, bioinformatic characterization and antibiotic resistance profiling were performed. RESULTS: In the 247 CRAB isolates characterized in this study, ST distribution varied by country: 29/31 (93.5%) Greek isolates, 34/41 (82.9%) Italian isolates and 70/175 (40.0%) Israeli isolates belonged to ST2. The identified ST2 isolates included eight distinct clades: 2C, 2D and 2H were significantly more common in Italy, while 2F was unique to Greece. The uncommon ST3 was not present among Greek isolates and constituted only 5/41 (12%) Italian isolates. On the other hand, it was much more common among Israeli isolates: 78/175 (44.6%) belonged to ST3. The vast majority of isolates, 240/247 (97.2%), were found to harbour acquired carbapenemases, primarily blaOXA-23. The chromosomal oxaAb (blaOXA-51-like) and ampC genes characteristic of this organism were also ubiquitous. Most (96.4%) ST3 isolates carried a broad-host-range plasmid IncP1α. CONCLUSIONS: The geographical differences in CRAB populations support the theory that clonal spread of CRAB leads to endemicity in hospitals and regions. The close association between antibiotic resistance genes and clades, and between plasmids and STs, suggest that de novo creation of MDR A. baumannii is rare. The clustering of antibiotic resistance genes and plasmids that is unique to each clade/ST, and nearly uniform within clades/STs, suggests that horizontal transmission is rare but crucial to the clade's/ST's success.

In vivo fitness of carbapenem-resistant Acinetobacter baumannii strains in murine infection is associated with treatment failure in human infections.

OBJECTIVES: Mortality among patients with carbapenem-resistant Acinetobacter baumannii (CRAB) infections varies between studies. We examined whether in vivo fitness of CRAB strains is associated with clinical outcomes in patients with CRAB infections. METHODS: Isolates were collected from patients enrolled in the AIDA trial with hospital-acquired pneumonia, bloodstream infections and/or urinary tract infections caused by CRAB. The primary outcome was 14-day clinical failure, defined as failure to meet all criteria: alive; haemodynamically stable; improved or stable Sequential Organ Failure Assessment (SOFA) score; improved or stable oxygenation; and microbiological cure of bacteraemia. The secondary outcome was 14-day mortality. We tested in vivo growth using a neutropenic murine thigh infection model. Fitness was defined based on the CFU count 24 hours after injection of an inoculum of 105 CFU. We used mixed-effects logistic regression to test the association between fitness and the two outcomes. RESULTS: The sample included 266 patients; 215 (80.8%) experienced clinical failure. CRAB fitness ranged from 5.23 to 10.08 log CFU/g. The odds of clinical failure increased by 62% for every 1-log CFU/g increase in fitness (OR 1.62, 95% CI 1.04-2.52). After adjusting for age, Charlson score, SOFA score and acquisition in the intensive care unit, fitness remained significant (adjusted OR 1.63, 95% CI 1.03-2.59). CRAB fitness had a similar effect on 14-day mortailty, although the association was not statistically significant (OR 1.56, 95% CI 0.95-2.57). It became significant after adjusting for age, Charlson score, SOFA score and recent surgery (adjusted OR 1.88, 95% CI 1.09-3.25). CONCLUSIONS: In vivo CRAB fitness was associated with clinical failure in patients with CRAB infection.

CRT implantation after transvenous lead/device extraction (TLE) in a patient with COVID-19: Endocarditis triggered by syndrome coronavirus 2 (SARS-COV-2) infection? A case report.

In the era of coronavirus disease 2019 (COVID-19), the management of cardiac implantable electronic devices infections with concomitant viral infection has not been completely defined yet. In this explorable context, we report the first experience of a Cardiac resynchronization therapy with defibrillator (CRT-D) implantation after transvenous lead extraction for endocarditis in a COVID-19 patient. We describe both the measures and procedures implemented to reduce the cross-infection in the operating room and our clinical practice to improving procedure effectiveness on patient care.

Diagnosis and treatment of pneumonia, a common cause of respiratory failure in patients with neuromuscular disorders.

Patients with neuromuscular diseases, during their illness are more susceptible to respiratory infections due to predisposing factors. Ineffective cough and the presence of atelectasis and hypoventilation, dysphagia and drooling can represent risk factors for the development of respiratory infection and fatal respiratory failure. Infections of respiratory tract with acute respiratory failure are the most common reason for hospitalizations, and pneumonia is among the leading causes of morbidity and mortality worldwide. The setting in which pneumonia is acquired heavily influences diagnostic and therapeutic choices. We will focus on aetiopathogenesis, diagnosis and treatment of pneumonia in these subjects, particularly considering the disease severity, rates of antibiotic resistance and the possible complications. In this case consultations with specialized physicians are strongly recommended.

Effects of adding L-arginine orally to standard therapy in patients with COVID-19: A randomized, double-blind, placebo-controlled, parallel-group trial. Results of the first interim analysis.

BACKGROUND: We and others have previously demonstrated that the endothelium is a primary target of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and L-arginine has been shown to improve endothelial dysfunction. However, the effects of L-arginine have never been evaluated in coronavirus disease 2019 (COVID-19). METHODS: This is a parallel-group, double-blind, randomized, placebo-controlled trial conducted on patients hospitalized for severe COVID-19. Patients received 1.66 g L-arginine twice a day or placebo, administered orally. The primary efficacy endpoint was a reduction in respiratory support assessed 10 and 20 days after randomization. Secondary outcomes were the length of in-hospital stay, the time to normalization of lymphocyte number, and the time to obtain a negative real-time reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2 on nasopharyngeal swab. This clinical trial had been registered at ClinicalTrials.gov, identifier: NCT04637906. FINDINGS: We present here the results of the initial interim analysis on the first 101 patients. No treatment-emergent serious adverse events were attributable to L-arginine. At 10-day evaluation, 71.1% of patients in the L-arginine arm and 44.4% in the placebo arm (p < 0.01) had the respiratory support reduced; however, a significant difference was not detected 20 days after randomization. Strikingly, patients treated with L-arginine exhibited a significantly reduced in-hospital stay vs placebo, with a median (interquartile range 25th,75th percentile) of 46 days (45,46) in the placebo group vs 25 days (21,26) in the L-arginine group (p < 0.0001); these findings were also confirmed after adjusting for potential confounders including age, duration of symptoms, comorbidities, D-dimer, as well as antiviral and anticoagulant treatments. The other secondary outcomes were not significantly different between groups. INTERPRETATION: In this interim analysis, adding oral L-arginine to standard therapy in patients with severe COVID-19 significantly decreases the length of hospitalization and reduces the respiratory support at 10 but not at 20 days after starting the treatment. FUNDING: Both placebo and L-arginine were kindly provided by Farmaceutici Damor S.p.A., Naples.

Risk Factors and Outcome of Multidrug-Resistant Infections after Heart Transplant: A Contemporary Single Center Experience.

(1) Background: The aim of this study was to assess risk factors for multidrug-resistant/extensively drug-resistant (MDR/XDR) bacterial infections in heart transplant (HT) patients within three months after surgery and its impact on patient outcome. (2) Methods: Retrospective analysis of clinical, hemato-chemical, imaging, treatment and outcome data from 47 heart transplant recipients from January 2016 to December 2018. MDR/XDR infections were compared to non-MDR/XDR and noninfected patients. (3) Results: Most participants were males, median age 51 years: 35 (74.5%) developed an infection after HT; 14 (29.8%) were MDR/XDR infections. Prolonged hospital stay before HT correlated to MDR/XDR infection (p < 0.001). Sequential organ failure assessment (SOFA) score at sampling day was higher in MDR/XDR (p = 0.027). MDR/XDR were mostly blood-stream (BSI) (p = 0.043) and skin-soft tissue (SSTI) (p = 0.047) infections. Gram-negative infections were the most frequent, specifically carbapenem-resistant Klebsiella pneumoniae. Antibiotic therapy duration for MDR/XDR infections was longer (p = 0.057), eradication rate lower (p = 0.083) and hospital stay longer (p = 0.005) but not associated with a worse outcome. (4) Conclusions: MDR/XDR infections affect compromised HT recipients with a history of prolonged hospitalization, causing a lower rate of eradication and increased hospital stay. These frequently present as BSI and SSTI. We emphasize the need to prevent contamination of central venous catheters and the surgical site.

D-Dimer as Biomarker for Early Prediction of Clinical Outcomes in Patients With Severe Invasive Infections Due to Streptococcus Pneumoniae and Neisseria Meningitidis.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection; no current clinical measure adequately reflects the concept of dysregulated response. Coagulation plays a pivotal role in the normal response to pathogens (immunothrombosis), thus the evolution toward sepsis-induced coagulopathy could be individuate through coagulation/fibrinolysis-related biomarkers. We focused on the role of D-dimer assessed within 24 h after admission in predicting clinical outcomes in a cohort of 270 patients hospitalized in a 79 months period for meningitis and/or bloodstream infections due to Streptococcus pneumoniae (n = 162) or Neisseria meningitidis (n = 108). Comparisons were performed with unpaired t-test, Mann-Whitney-test or chi-squared-test with continuity correction, as appropriate, and multivariable logistic regression analysis was performed with Bayesian model averaging. In-hospital mortality was 14.8% for the overall population, significantly higher in S. pneumoniae than in N. meningitidis patients: 19.1 vs. 8.3%, respectively (p = 0.014). At univariable logistic regression analysis the following variables were significantly associated with in-hospital mortality: pneumococcal etiology, female sex, age, ICU admission, SOFA score, septic shock, MODS, and D-dimer levels. At multivariable analysis D-dimer showed an effect only in N. meningitidis subgroup: as 500 ng/mL of D-dimer increased, the probability of unfavorable outcome increased on average by 4%. Median D-dimer was significantly higher in N. meningitidis than in S. pneumoniae patients (1,314 vs. 1,055 ng/mL, p = 0.009). For N. meningitidis in-hospital mortality was 0% for D-dimer <500 ng/mL, very low (3.5%) for D-dimer <7,000 ng/mL, and increased to 26.1% for D-dimer >7,000 ng/mL. Kaplan-Meier analysis of in-hospital mortality showed for N. meningitidis infections a statistically significant difference for D-dimer >7,000 ng/mL compared to values <500 ng/mL (p = 0.021) and 500-3,000 ng/mL (p = 0.002). For S. pneumoniae the mortality risk resulted always high, over 10%, irrespective by D-dimer values. In conclusion, D-dimer is rapid to be obtained, at low cost and available everywhere, and can help stratify the risk of in-hospital mortality and complications in patients with invasive infections due to N. meningitidis: D-dimer <500 ng/mL excludes any further complications, and a cut-off of 7,000 ng/mL seems able to predict a significantly increased mortality risk from much <10% to over 25%.

Diagnostic and infection control strategies for Clostridioides difficile infections in a setting of high antimicrobial resistance prevalence.

Clostridioides difficile (CD) is a major nosocomial pathogen and the leading cause of antibiotic-associated diarrhoea. In light of the strong association between antimicrobial use and CD infections (CDI), it may be hypothesised that areas at higher prevalence of antimicrobial resistance, like the region of Campania in southern Italy, could also have a higher rate of CDI. In this multicentre, region-based, prospective study, we analysed such issues, exploiting CDI incidence data collected from local hospitals. In 2016, the Italian National Centre for Disease Control supported a project involving three Italian regions: Friuli Venezia Giulia, Lazio and Campania. In Campania, a network of 49 hospitals willing to participate in the project was created. The project consisted of two phases: a survey on practice patterns concerning CDI and an epidemiological surveillance study. We identified a stringent need to improve awareness about CDI among the regional health-care community, as a widespread lack of surveillance programmes for CDI control was observed (existing in only 40% of participating facilities). Moreover, almost half of the participating hospitals (n=16, 43%) had no standardised procedures or protocols to control and prevent CDI. In the second phase of the study, we collected data of CDI cases during a six-month surveillance programme. In all, 87 CDI cases were observed, for a total of 903,334 patient bed-days and 122,988 admissions. According to the above data, CDI incidence was 0.96 cases/10000 patient bed-days, much lower than expected based on prior studies conducted elsewhere. The results of our study suggest CDI remains a rather neglected clinical issue in Campania. Despite a high burden of antimicrobial resistance and antimicrobial use in our geographic setting, we observed a very low incidence of CDI. Such a low incidence could be explained by underdiagnosis, but could also be related to actual diet, the lower patient age or the specific genetic background. However, further studies are warranted to either confirm or rebut the above hypotheses.

Enterococcal infective endocarditis is a marker of current occult or future incident colorectal neoplasia.

BACKGROUND: Few studies suggest an association between Enterococcal infective endocarditis (EIE) and colorectal disease, including colorectal neoplasia (CRN) and colorectal cancer (CRC). In this study, we analyze differences in prevalence, risk factors and outcome of CRN and CRC between EIE and Streptococcus gallolyticus infective endocarditis (SGIE). METHODS: Single center, observational study of 166 patients with definite EIE or SGIE. Clinical data were collected prospectively in a standardized IE protocol. Colonoscopy data were collected retrospectively on 90 patients. RESULTS: 85 patients had EIE, 81 SGIE. EIE patients had a higher rate of prior cancer (20% vs 6%) and health-care associated infection (12% vs 1%), but similar mortality than SGIE. Colonoscopy performed in 90 patients showed intestinal diseases in 30 of 42 (71%) EIE patients vs. 40 of 48 (83%) SGIE patients (p = 0.174), with a predominance of CRN. Among 78 patients who underwent colonoscopy after IE diagnosis, no difference between EIE and SGIE was observed in the rate of non-neoplastic lesions (48% vs 47%), benign (32% vs 40%) or malignant (13% vs 15%) neoplastic lesions. Adverse events during colonoscopy were uncommon, although a careful handling of anticoagulation was required. CONCLUSIONS: EIE seems to be associated with colorectal disease, including colorectal neoplasia and colorectal cancer, to the same extent as SGIE. EIE should be considered a marker of colorectal neoplasia, even in patients with a clear health-care related acquisition. Colonoscopy is generally safe in EIE patients, and should be considered to early diagnose and treat colorectal disease.

Colistin plus meropenem for carbapenem-resistant Gram-negative infections: in vitro synergism is not associated with better clinical outcomes.

OBJECTIVES: In vitro models showing synergism between polymyxins and carbapenems support combination treatment for carbapenem-resistant Gram-negative (CRGN) infections. We tested the association between the presence of in vitro synergism and clinical outcomes in patients treated with colistin plus meropenem. METHODS: This was a secondary analysis of AIDA, a randomized controlled trial comparing colistin with colistin-meropenem for severe CRGN infections. We tested in vitro synergism using a checkerboard assay. Based on the fractional inhibitory concentration (ΣFIC) index for each colistin-meropenem combination, we categorized results as synergistic, antagonistic or additive/indifferent. The primary outcome was clinical failure at 14 days. Secondary outcomes were 14- and 28-day mortality and microbiological failure. RESULTS: The sample included 171 patients with infections caused by carbapenem-resistant Acinetobacter baumannii (n = 131), Enterobacteriaceae (n = 37) and Pseudomonas aeuruginosa (n = 3). In vitro testing showed synergism for 73 isolates, antagonism for 20 and additivism/indifference for 78. In patients who received any colistin plus meropenem, clinical failure at 14 days was 59/78 (75.6%) in the additivism/indifference group (reference category), 54/73 (74.0%) in the synergism group (adjusted odds ratio (aOR) 0.76, 95% CI 0.31-1.83), and 11/20 (55%) in the antagonism group (aOR 0.77, 95% CI 0.22-2.73). There was no significant difference between groups for any secondary outcome. Comparing the synergism group to patients treated with colistin monotherapy, synergism was not protective against 14-day clinical failure (aOR 0.52, 95% CI 0.26-1.04) or 14-day mortality (aOR1.09, 95% CI 0.60-1.96). DISCUSSION: In vitro synergism between colistin and meropenem via checkerboard method did not translate into clinical benefit.

Candida palmioleophila isolation in Italy from two cases of systemic infection, after a CHROMagar and Vitek system mis-identification as C. albicans.

A correct, fast, reliable identification method is pivotal in nosocomial environments to guide treatment strategies, whereas misidentification might lead to treatment failure. For routine identifications the Vitek system and CHROMagar are widely used but not always reliable, especially now with an increasing number of new emerging fungal pathogens that need careful identification. Here we describe two cases of candidemia, due to Candida palmioleophila previously misidentified as Candida albicans by using the Vitek2 system and CHROMagar. The first case is a 54-year-old man with an infected ulcer in the lower right limb, treated with a targeted therapy using a central venous catheter (CVC). After two months he developed a CVC-related candidemia MDR identified as C. albicans. The second case is a 2-month-old male baby that was admitted to the neonatal unit with acute respiratory failure due to a severe community-acquired bilateral pneumonia; blood cultures were all positive for C. albicans MDR. The isolated strains where re-identified with Maldi-Tof and DNA sequencing as C. palmioleophila. From the identification point of view, CHROMagar can be clearly misleading, especially because CHROMagar types currently available are not designed to discriminate new emerging species, suggesting that systems other than MALDI-TOF and marker sequencing may be inadequate even for routine identification and could contribute to producing misleading identifications and therapeutically wrong practices, leading to failures and patient death.