Pannonibacter anstelovis sp. nov. Isolated from Two Cases of Bloodstream Infections in Paediatric Patients.

This study describes two cases of bacteraemia sustained by a new putative Pannonibacter species isolated at the U.O.C. of Microbiology and Virology of the Policlinico of Bari (Bari, Italy) from the blood cultures of two patients admitted to the Paediatric Oncohaematology Unit. Pannonibacter spp. is an environmental Gram-negative bacterium not commonly associated with nosocomial infections. Species identification was performed using Sanger sequencing of the 16S rRNA gene and Whole-Genome Sequencing (WGS) for both strains. Genomic analyses for the two isolates, BLAST similarity search, and phylogeny for the 16S rDNA sequences lead to an assignment to the species Pannonibacter phragmitetus. However, by performing ANIb, ANIm, tetranucleotide correlation, and DNA-DNA digital hybridization, analyses of the two draft genomes showed that they were very different from those of the species P. phragmitetus. MALDI-TOF analysis, assessment of antimicrobial susceptibility by E-test method, and Analytical Profile Index (API) tests were also performed. This result highlights how environmental bacterial species can easily adapt to the human host and, especially in nosocomial environments, also gain pathogenic potential through antimicrobial resistance.

Case series study of nosocomial Legionnaires' disease in Apulia region (southern Italy): The role of different molecular methods in identifying the infection source

BACKGROUND AND AIM: Legionnaires' disease is a severe form of pneumonia caused by the inhalation or aspiration of water droplets contaminated with Legionella pneumophila and other Legionella species. These bacteria are commonly found in natural habitats and man-made water systems. Legionnaires' disease is a significant public health problem, especially in healthcare settings where patients may be exposed to contaminated environmental sources. Nosocomial outbreaks have been reported worldwide, leading to high morbidity and mortality rates, and increased healthcare costs. This study aimed to compare, the clonal relationship of clinical L. pneumophila strains from two different hospitals with L. pneumophila strains isolated from the water supply. METHODS: In the period from 2019 to 2021, clinical and environmental strains involved in three cases of legionellosis were compared by means of pulsed field gel electrophoresis and sequence based typing techniques. RESULTS: Our findings highlight the persistence of clonally distinct strains within each hospital examined. Furthermore, the L. pneumophila strains detected from hospital environmental sources were related to the clinical strains isolated, demonstrating the nosocomial origin of these cases. CONCLUSIONS: Therefore, it is important to implement more accurate surveillance systems both for epidemiological studies and to check the effectiveness of remediation procedures. (www.actabiomedica.it).

Cefiderocol Versus Colistin for the Treatment of Carbapenem-Resistant Acinetobacter baumannii Complex Bloodstream Infections: A Retrospective, Propensity-Score Adjusted, Monocentric Cohort Study.

INTRODUCTION: Bloodstream infections (BSI) caused by carbapenem-resistant Acinetobacter baumannii (CRAB) are associated with high mortality with limited treatment. The aim of this study is to compare effectiveness and safety of colistin-based versus cefiderocol-based therapies for CRAB-BSI. METHODS: This is a retrospective observational study enrolling patients with monomicrobial CRAB-BSIs treated with colistin or cefiderocol from 1 January 2020, to 31 December 2022. The 30-day all-cause mortality rate was the primary outcome. A Cox regression analysis was performed to identify factors independently associated with mortality. A propensity score analysis using inverse probability of treatment weighting (IPTW) was also performed. RESULTS: Overall 118 patients were enrolled, 75 (63%) and 43 (37%) treated with colistin- and cefiderocol-based regimens. The median (q1-q3) age was 70 (62-79) years; 70 (59%) patients were men. The 30-day all-cause mortality was 52%, significantly lower in the cefiderocol group (40% vs 59%, p = 0.045). By performing a Cox regression model, age (aHR = 1.03, 95% CI 1.00-1.05), septic shock (aHR = 1.93, 95% CI 1.05-3.53), and delayed targeted therapy (aHR = 2.42, 95% CI 1.11-5.25) were independent predictors of mortality, while cefiderocol-based therapy was protective (aHR = 0.49, 95% CI 0.25-0.93). The IPTW-adjusted Cox analysis confirmed the protective effect of cefiderocol (aHR = 0.53, 95% CI 0.27-0.98). CONCLUSIONS: Cefiderocol may be a valuable treatment option for CRAB-BSI, especially in the current context of limited treatment options.

Looking for Stenotrophomonas maltophilia treatment: in vitro activity of ceftazidime/avibactam alone and in combination with aztreonam.

During the Sars-Cov-2 pandemic, Stenotrophomonas maltophilia (S.maltophilia) secondary pulmonary infections have increased, especially in critically ill patients, highlighting the need for new therapeutic options. Trimethoprim-sulfamethoxazole (SXT) is the treatment of choice but the increase of resistant strains or adverse drug reactions limited its clinical use. Recently ceftazidime/avibactam (CZA) has been approved for the treatment of multi drug resistant (MDR) Gram-negative bacteria infections, including hospital acquired pneumonia. The aim of this study was to evaluate the in vitro activity of ceftazidime/avibactam (CZA) alone and in combination with aztreonam (ATM) against S. maltophilia clinical isolates by E-test method. Susceptibility of SXT and levofloxacin (LEV) was also investigated. Our results showed 22% of resistance to CZA, 2% to SXT and 26% to LEV. CZA in combination with ATM demonstrated synergistic activity against 86% of the strains, including all those resistant to CZA. The combination of CZA with ATM provides a new therapeutic option for the treatment of severe respiratory infections in critically ill patients.

Coinfections in intensive care units. Has anything changed with Covid-19 pandemia?

BACKGROUND AND AIM: Since December 2019, the Coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2), has spread from China, becoming a pandemic. Bacterial and fungal co-infections may lead to increase in COVID-19 severity with a decrease in patients survive. The aim of this work was to evaluate bacterial and fungal co-infections in COVID-19 patients admitted to ICU in comparison with patients recovered in ICU in pre-COVID-19 era in order to understand whether the pandemic had changed the incidence of overinfections in patients admitted to ICU. In fact, the epidemiological data should guide the choice of empirical therapy. METHODS: During pandemic, AOUC Policlinico of Bari organized dedicated ICUs for patient with SARS-CoV-2. Blood cultures, urine, and tracheobronchial aspirate were included in the analysis. RESULTS: Specimens of 1905 patients were analysed in this work. Comparing clinical isolates prevalence by material and COVID-19 vs. non-COVID-19 patients statistically significant differences were detected for A. baumannii complex, Aspergillus fumigatus, Escherichia coli, Haemophilus influenzae and Serratia marcescens isolated from tracheobronchial aspirates; C. albicans from urine samples, A. baumannii complex, Enterococcus faecalis and Enterococcus faecium isolated from blood culture. CONCLUSIONS: Although the organisms isolated in COVID-19 patients are consistent with those frequently associated with healthcare associated infection, our data suggest a particular prevalence in COVID-19 patients of A. baumannii, Stenotrophomonas maltophilia and Aspergillus spp. in the respiratory tract, C. albicans in urine and  A. baumannii, E. faecalis and E. faecium in blood cultures.

Effectiveness of First-Line Therapy with Old and Novel Antibiotics in Ventilator-Associated Pneumonia Caused by Carbapenem-Resistant Acinetobacter baumannii: A Real Life, Prospective, Observational, Single-Center Study.

Evidence-based, standard antibiotic therapy for ventilator-associated pneumonia (VAP) caused by carbapenem-resistant Acinetobacter baumannii (CRAB) is a relevant unmet clinical need in the intensive care unit (ICU). We aimed to evaluate the effectiveness of first-line therapy with old and novel CRAB active antibiotics in monomicrobial VAP caused by CRAB. A prospective, observational study was performed in a mixed non-COVID-19 ICU. The primary outcome measure was clinical failure upon first-line targeted therapy. Features independently influencing failure occurrence were also investigated via Cox proportional multivariable analysis. To account for the imbalance in antibiotic treatment allocation, a propensity score analysis with an inverse probability treatment weighting approach was adopted. Of the 90 enrolled patients, 34 (38%) experienced clinical failure. Compared to patients who experienced a clinical resolution of VAP, those who had clinical failure were of an older age (median age 71 (IQR 64-78) vs. 62 (IQR 52-69) years), and showed greater burden of comorbidities (median Charlson comorbidity index 8 (IQR 6-8) vs. 4 (IQR 2-6)), higher frequency of immunodepression (44% vs. 21%), and greater clinical severity at VAP onset (median SOFA score 10 (IQR 9-11) vs. 9 (IQR 7-11)). Lower rates of use of fast molecular diagnostics for nosocomial pneumonia (8.8% vs. 30.3%) and of timely CRAB active therapy administration (65% vs. 89%), and higher rates of colistin-based targeted therapy (71% vs. 46%) were also observed in patients who failed first-line therapy. Overall, CRAB active iv regimens were colistin-based in 50 patients and cefiderocol-based in 40 patients, both always combined with inhaled colistin. According to the backbone agent of first-line regimens, clinical failure was lower in the cefiderocol group, compared to that in the colistin group (25% vs. 48%, respectively). In multivariable Cox regression analysis, the burden of comorbid conditions independently predicted clinical failure occurrence (Charlson index aHR = 1.21, 95% CI = 1.04-1.42, p = 0.01), while timely targeted antibiotic treatment (aHR = 0.40, 95% CI = 0.19-0.84, p = 0.01) and cefiderocol-based first-line regimens (aHR = 0.38, 95% CI = 0.17-0.85, p = 0.02) strongly reduced failure risk. In patients with VAP caused by CRAB, timely active therapy improves infection outcomes and cefiderocol holds promise as a first-line therapeutic option.

Thoracic aorta graft infection by avibactam-resistant KPC-producing K. pneumoniae treated with meropenem/vaborbactam: a case report and literature review.

Meropenem/vaborbactam (M/V) is a new carbapenem-carbapenemase inhibitor combination drug active against extensively drug resistant Gram-negative pathogens. Studies about its efficacy and place in therapy are limited in "real-life" and no data are available for deep site infections, like vascular graft infections. We present a case of a patient successfully treated with M/V for a thoracic aorta graft infection, placed for a traumatic penetrating aortic ulcer, due to an extensively KPC-producing Klebsiella pneumoniae resistant to ceftazidime/ avibactam. Furthermore, we conducted a systematic literature review concerning vascular graft infections caused by carbapenem-resistant Klebsiella pneumoniae and the papers published until now about the use of M/V for the treatment of ceftazidime/avibactam-resistant K. pneumoniae. Meropenem/vaborbactam is a promising antibiotic for difficult-to-treat Gram-negative bacteria with limited therapeutic options. Only few reports have been published and more studies are needed to assess which is the best place in therapy of M/V.

Tendency in Pulmonary Aspergillosis Investigation during the COVID-19 Era: What Is Changing?

Aspergillosis is a disease caused by Aspergillus, and invasive pulmonary aspergillosis (IPA) is the most common invasive fungal infection leading to death in severely immuno-compromised patients. The literature reports Aspergillus co-infections in patients with COVID-19 (CAPA). Diagnosing CAPA clinically is complex since the symptoms are non-specific, and performing a bronchoscopy is difficult. Generally, the microbiological diagnosis of aspergillosis is based on cultural methods and on searching for the circulating antigens galactomannan and 1,3-ß-D-glucan in the bronchoalveolar lavage fluid (bGM) or serum (sGM). In this study, to verify whether the COVID-19 period has stimulated clinicians to pay greater attention to IPA in patients with respiratory tract infections, we evaluated the number of requests for GM-Ag research and the number of positive tests found during the pre-COVID-19 and COVID-19 periods. Our data show a significant upward trend in GM-Ag requests and positivity from the pre-COVID to COVID period, which is attributable in particular to the increase in IPA risk factors as a complication of COVID-19. In the COVID period, parallel to the increase in requests, the number of positive tests for GM-Ag also increased, going from 2.5% in the first period of 2020 to 12.3% in the first period of 2021.

Predictors for Pulmonary Tuberculosis Outcome and Adverse Events in an Italian Referral Hospital: A Nine-Year Retrospective Study (2013-2021).

Background: The COVID-19 pandemic has undone years of progress in providing essential TB services and controlling the TB burden. Italy, a low TB burden country, has an incidence of 7.1 cases per 100,000 people. To control the TB spreading in Italy is critical to investigate the characteristics of patients with the worst outcomes and the highest risk of adverse events related to antituberculosis therapy. Therefore, we conducted a large retrospective study in TB patients admitted to the Clinic of Infectious Diseases University of Bari, Italy, in order to describe the clinical presentation and the factors associated with adverse events and outcomes. Methods: We retrospectively evaluated the patients admitted to the Clinic of Infectious Diseases from January 2013 to 15 December 2021. We stratified our cohort into two groups: <65 years of age and ≥65 years in order to assess any differences between the two groups. Two logistic regression models were implemented considering the dependent variables as: (I) the adverse events; and (II) the unsuccessful treatments. Results: In total, 206 consecutive patients [60% (n = 124) M, median age 39 years, range 16-92] were diagnosed and admitted with TB at Clinic of Infectious Diseases. Of the whole sample, 151 (74%) were <65 years and 55 (26%) were ≥65. Statistically significant differences between the two groups were detected (p-value < 0.05) for nationality (p-value = 0.01), previous contact with TB patient (p-value = 0.00), type of TB (p-value = 0.00), unsuccessful treatment (p-value = 0.00), length of hospitalization (p-value = 0.02) and diagnostic delay (p-value = 0.01). Adverse events related to TB drug regimen were reported in 24% (n = 49). Age < 65 years (O.R. = 3.91; 95% CI 1.72-4.21), non-Italian nationality (O.R. = 4.45; 95% CI 2.22-4.98.), homeless (O.R. = 3.23; 95% CI 2.58-4.54), presence of respiratory symptoms (O.R. = 1.23; 95% CI 1.10-1.90), diagnostic delay (O.R = 2.55; 95% CI 1.98-3.77) resulted associated with unsuccessful treatment outcome (death, failure or lost to follow up). Finally, age < 65 years (O.R. = 1.73; 95% CI 1.31-2.49), presence of pulmonary TB (O.R. = 1.15; 95% CI 1.02-1.35), length of hospitalization (O.R. = 1.82; 95% CI 1.35-2.57) and TB culture positive (O.R. = 1.35; 95% CI 1.12-1.82) were associated with adverse events in our populations. Conclusions: The pharmacological approach alone seems insufficient to treat and cure a disease whose ethiopathogenesis is not only due to the Mycobacterium tuberculosis, but also to the poverty or the social fragility. Our data suggest that young foreigners, the homeless, and the people with low social and economic status are at higher risk of an unfavorable outcome in low incidence TB countries. Targeted actions to support this highly vulnerable population both in terms of outcome and occurrence of adverse events are needed.

Impact of Vitamin D in Prophylaxis and Treatment in Tuberculosis Patients.

Vitamin D plays a crucial role in many infectious diseases, such as tuberculosis (TB), that remains one of the world's top infectious killers with 1.5 million deaths from TB in 2021. Vitamin D suppresses the replication of Mycobacterium tuberculosis in vitro and showed a promising role in TB management as a result of its connection with oxidative balance. Our review encourages the possible in vivo benefit of a joint administration with other vitamins, such as vitamin A, which share a known antimycobacterial action with vitamin D. However, considering the low incidence of side effects even at high dosages and its low cost, it would be advisable to assess vitamin D level both in patients with active TB and high-risk groups and administer it, at least to reach sufficiency levels.

Emerging issue of fluconazole-resistant candidemia in a tertiary care hospital of southern italy: time for antifungal stewardship program.

An increased number of patients is at risk of Candida spp. bloodstream infection (CBSI) in modern medicine. Moreover, the rising of antifungal resistance (AR) was recently reported. All consecutive CBSI occurred in our Hospital (consisting of 1,370 beds) between 2015 and 2018, were reviewed. For each case, Candida species, AR pattern, ward involved and demographic data of patients were recorded. Overall, 304 episodes of CBSI occurred, with a median (q1:first-,q3:third quartile) of 77 (71-82) CBSI/year. Over the years, a significant increase of CBSI due to C. albicans compared to non-albicans strains was recorded in medical wards (from 65% to 71%, p=0.030), while this ratio remained stable in others. An increase of resistant strains to multiple antifungals such as C. guillermondii was noticed in recent years (from 0% to 9.8%, p=0.008). Additionally, from 2015 to 2018 an increase in fluconazole-resistance was recorded in our Hospital (from 7.4% to 17.4%, p=0.025) and a slight increase in voriconazole-resistance (from 0% to 7% in 2018, p=0.161) was observed, while resistance to echinocandin and amphotericin B remained firmly below 2%. This study suggests a rapid spread of antifungal resistance in our Hospital; therefore, an appropriate antifungal stewardship programs is urgently warranted.

Potential Role of Vitamins A, B, C, D and E in TB Treatment and Prevention: A Narrative Review.

(1) Background: Tuberculosis (TB) is one of the world's top infectious killers, in fact every year 10 million people fall ill with TB and 1.5 million people die from TB. Vitamins have an important role in vital functions, due to their anti-oxidant, pro-oxidant, anti-inflammatory effects and to metabolic functions. The aim of this review is to discuss and summarize the evidence and still open questions regarding vitamin supplementation as a prophylactic measure in those who are at high risk of Mycobacterium tuberculosis (MTB) infection and active TB; (2) Methods: We conducted a search on PubMed, Scopus, Google Scholar, EMBASE, Cochrane Library and WHO websites starting from March 1950 to September 2021, in order to identify articles discussing the role of Vitamins A, B, C, D and E and Tuberculosis; (3) Results: Supplementation with multiple micronutrients (including zinc) rather than vitamin A alone may be more beneficial in TB. The WHO recommend Pyridoxine (vitamin B6) when high-dose isoniazid is administered. High concentrations of vitamin C sterilize drug-susceptible, MDR and extensively drug-resistant MTB cultures and prevent the emergence of drug persisters; Vitamin D suppresses the replication of mycobacterium in vitro while VE showed a promising role in TB management as a result of its connection with oxidative balance; (4) Conclusions: Our review suggests and encourages the use of vitamins in TB patients. In fact, their use may improve outcomes by helping both nutritionally and by interacting directly and/or indirectly with MTB. Several and more comprehensive trials are needed to reinforce these suggestions.

Meropenem/vaborbactam activity in vitro: a new option for Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae treatment.

Aim: Infections by Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae represent a major challenge because of limited treatment strategies. New ß-lactam/ß-lactamase inhibitor associations may help to deal with this challenge. The aim of this study is to evaluate the in vitro susceptibility of KPC-producing K. pneumoniae for meropenem/vaborbactam in comparison with ceftazidime/avibactam against. Materials and methods: Twenty-eight strains isolated from blood cultures were evaluated. Testing for susceptibility to meropenem/vaborbactam and ceftazidime/avibactam was performed by E-test gradient strip. Results: All the clinical isolates were susceptible to meropenem/vaborbactam, while one strain was resistant to ceftazidime/avibactam with a MIC of 32 µg/ml. The median MIC of ceftazidime/avibactam evaluated after standardization was higher compared with that of meropenem/vaborbactam. Conclusion: Meropenem/vaborbactam could be an important turning point in the treatment of KPC-producing K. pneumoniae infections, especially considering the emergence of ceftazidime/avibactam resistance.

Lay abstract Carbapenem-resistant Klebsiella pneumoniae is responsible, in critically ill patients, for nosocomial infections that are difficult to treat due to limited therapeutic options. Today, new antibiotics are available for treating these infections. The aim of this study is to evaluate the antimicrobial activity of meropenem/vaborbactam versus ceftazidime/avibactam. The results demonstrate that meropenem/vaborbactam could be an important turning point in the treatment of carbapenem-resistant K. pneumoniae infections, considering the emergence of ceftazidime/avibactam resistance.

A Possible Outbreak by Serratia marcescens: Genetic Relatedness between Clinical and Environmental Strains.

Serratia marcescens (SM) is a Gram-negative bacterium that is frequently found in the environment. Since 1913, when its pathogenicity was first demonstrated, the number of infections caused by SM has increased. There is ample evidence that SM causes nosocomial infections in immunocompromised or critically ill patients admitted to the intensive care units (ICUs), but also in newborns admitted to neonatal ICUs (NICUs). In this study, we evaluated the possible genetic correlation by PFGE between clinical and environmental SM strains from NICU and ICU and compared the genetic profile of clinical strains with strains isolated from patients admitted to other wards of the same hospital. We found distinct clonally related groups of SM strains circulating among different wards of a large university hospital. In particular, the clonal relationship between clinical and environmental strains in NICU and ICU 1 was highlighted. The identification of clonal relationships between clinical and environmental strains in the wards allowed identification of the epidemic and rapid implementation of adequate measures to stop the spread of SM.

Cefiderocol-Based Combination Therapy for "Difficult-to-Treat" Gram-Negative Severe Infections: Real-Life Case Series and Future Perspectives.

Cefiderocol is a new cephalosporin displaying against extensively resistant (XDR) Gram-negative bacteria. We report our experience with cefiderocol-based combination therapies as "rescue" treatments in immunocompromised or critically ill patients or in patients with post-surgical infections who had failed previous regimens. A total of 13 patients were treated from 1 September 2020 to 31 March 2021. In total, 5/13 (38%) patients were classified as critically ill, due to severe COVID-19 lung failure; 4/13 (31%) patients had post-surgical infections and 4/13 (31%) had severe infections in immunocompromised subjects due to solid organ transplantation (2/4) or hematological malignancy (2/4). Overall, 10/13 infections were caused by carbapenem-resistant Acinetobacter baumannii, one by KPC-positive ceftazidime/avibactam-resistant Klebsiella pneumonia and two by Pseudomonas aeruginosa XDR. Based on clinical, microbiological and hematobiochemical evaluation, cefiderocol was associated with different companion drugs, particularly with fosfomycin, high-dose tigecycline and/or colistin. Microbiological eradication was achieved in all cases and the 30-day survival rate was 10/13; two patients died due to SARS-CoV-2 lung failure, whereas one death was attributed to subsequent infections. No recurrent infections within 30 days were reported. Finally, we hereby discuss the therapeutic potential of cefiderocol and the possible place in the therapy of this novel drug.

Recurrent neurosurgical site infection by extensively drug-resistant P. aeruginosa treated with cefiderocol: a case report and literature review.

INTRODUCTION: Cefiderocol is a new siderophore cephalosporin designed to be active against extensively resistant Gram-negative bacteria; however, clinical studies are limited to complicated urinary tract infections, pneumonia, and intra-abdominal infections. To date, no data are available on neurosurgical site infections. CASE PRESENTATION: We present a case of a patient successfully cured with Cefiderocol for a neurosurgical site infection due to extensively resistant P. aeruginosa, who had failed a previous treatment based on combined antimicrobial therapy and right parietal bone excision. CONCLUSIONS: Cefiderocol is a promising antibiotic for complicated infections due to multidrug resistant gram-negative bacteria.