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Background In the late 1990s, as a response to rising antimicrobial resistance (AMR), an independent multinational, interdisciplinary group was formed specifically targeting primary care antibiotic prescribing for community-acquired respiratory tract infections (CA-RTIs). The group comprised senior clinicians from Canada, Israel, Spain, Sweden, UK and USA. The group's objectives were to provide recommendations for antibiotic stewardship in the community because, whilst it was widely accepted that inappropriate antibiotic use was contributing to AMR, it remained difficult to change prescribing behaviour. The group aimed to identify principles underlying appropriate antibiotic prescribing and guideline formulation to reduce morbidity from CA-RTIs, limit therapeutic failure and, importantly, curb AMR emergence. The group published a report in 2002, which has become known as the Consensus Principles. Objectives (i) To consider the relevance of the Consensus Principles in 2022 by reviewing current global approaches to rising AMR. A wide range of factors, such as antibiotic overuse, most recently seen in COVID-19 patients, are still driving rising AMR even though there has been a high-level international response to the AMR threat; and (ii) as an introduction to this Supplement, which reports the findings of analyses of how AMR is being addressed in nine disparate countries (Brazil, India, Kuwait, Mexico, Pakistan, Russia, Saudi Arabia, Türkiye and Vietnam). Understanding how these initiatives are being pursued in different countries helps identify areas where more information is needed. Conclusions Adherence to the Consensus Principles remains as important now as it was in 2002. Achieving appropriate antibiotic prescribing is a vital objective in order that the right patient receives the right antibiotics at the right time to ensure optimal clinical outcomes while at the same time helping to limit further increases in AMR. [ABSTRACT FROM AUTHOR]

• Antimicrobial resistance (AMR) threatens public health worldwide. • Comprehensive surveillance programmes are essential to combatting AMR. • SMART is a long-running, robust, global surveillance programme. • Data are also collected from resource-limited countries especially impacted by AMR. • SMART data can inform treatment guidelines and clinical decision-making. Antimicrobial resistance (AMR) is a major global public health threat, particularly affecting patients in resource-poor settings. Comprehensive surveillance programmes are essential to reducing the high mortality and morbidity associated with AMR and are integral to informing treatment decisions and guidelines, appraising the effectiveness of intervention strategies, and directing development of new antibacterial agents. Various surveillance programmes exist worldwide, including those administered by government bodies or funded by the pharmaceutical industry. One of the largest and longest running industry-sponsored AMR surveillance programme is the Study for Monitoring Antimicrobial Resistance Trends (SMART), which recently completed its 20th year. The SMART database has grown to almost 500 000 isolates from over 200 sites in more than 60 countries, encompassing all major geographic regions and including many sites in low- and middle-income countries. The SMART surveillance programme has evolved in scope over time, including additional antibacterial agents, pathogens and infection sites, in line with changing epidemiology and medical need. Surveillance data from SMART and similar programmes have been used successfully to detect emerging resistance threats and AMR patterns in specific countries and regions, thus informing national and local clinical treatment guidelines. The SMART database can be accessed readily by physicians and researchers globally, which may be especially valuable to those from countries with limited healthcare resources, where surveillance and resistance data are rarely collected. Continued participation from as many sites as possible worldwide and maintenance of adequate funding are critical factors to fully realising the potential of large-scale AMR surveillance programmes into the future. [ABSTRACT FROM AUTHOR]

Objectives: To compare the concordance of ceftaroline MIC values by reference broth microdilution (BMD) and Etest (bioMérieux, France) for MSSA and MRSA isolates obtained from PREMIUM (D372SL00001), a European multicentre study.Methods: Ceftaroline MICs were determined by reference BMD and by Etest for 1242 MSSA and MRSA isolates collected between February and May 2012 from adult patients with community-acquired pneumonia or complicated skin and soft tissue infections; tests were performed across six European laboratories. Selected isolates with ceftaroline resistance in broth (MIC >1 mg/L) were retested in three central laboratories to confirm their behaviour.Results: Overall concordance between BMD and Etest was good, with >97% essential agreement and >95% categorical agreement. Nevertheless, 12 of the 26 MRSA isolates found resistant by BMD scored as susceptible by Etest, with MICs ≤1 mg/L, thus counting as very major errors, whereas only 5 of 380 MRSA isolates found ceftaroline susceptible in BMD were miscategorized as resistant by Etest. Twenty-one of the 26 isolates with MICs of 2 mg/L by BMD were then retested twice by each of three central laboratories: BMD MICs of 2 mg/L were consistently found for 19 of the 21 isolates. Among 147 Etest results for these 21 isolates (original plus six repeats per isolate) 112 were >1 mg/L.Conclusions: BMD and Etest have good overall agreement for ceftaroline against Staphylococcus aureus; nevertheless, reliable Etest-based discrimination of the minority of ceftaroline-resistant (MIC 2 mg/L) MRSA is extremely challenging, requiring careful reading of strips, ideally with duplicate testing. [ABSTRACT FROM AUTHOR]

Recent clinical isolates of key Gram-negative and Gram-positive bacteria were collected in 2012 from hospitalised patients in medical centres in four European countries (France, Germany, Italy and Spain) and were tested using standard broth microdilution methodology to assess the impact of 4 mg/L avibactam on the in vitro activities of ceftazidime, ceftaroline and aztreonam. Against Enterobacteriaceae, addition of avibactam significantly enhanced the level of activity of these antimicrobials. MIC 90 values (minimum inhibitory concentration that inhibits 90% of the isolates) of ceftazidime, ceftaroline and aztreonam for Escherichia coli , Klebsiella pneumoniae , Enterobacter cloacae , Enterobacter aerogenes , Citrobacter freundii and Morganella morganii were reduced up to 128-fold or greater when combined with avibactam. A two-fold reduction in the MIC 90 of ceftazidime to 8 mg/L was noted in Pseudomonas aeruginosa isolates when combined with avibactam, whereas little effect of avibactam was noted on the MIC values of the test compounds when tested against Acinetobacter baumannii isolates. Avibactam had little effect on the excellent activity of ceftazidime, ceftaroline and aztreonam against Haemophilus influenzae. It had no impact on the in vitro activity of ceftazidime and ceftaroline against staphylococci and streptococci. This study demonstrates that addition of avibactam enhances the activities of ceftazidime, ceftaroline and aztreonam against Enterobacteriaceae and P. aeruginosa but not against A. baumannii. [ABSTRACT FROM AUTHOR]

National dissemination of EUCAST guidelines is a shared responsibility In preparation for all major decisions, EUCAST encourages National AST Committees (NACs) to discuss and inform national colleagues and to respond to consultations - all NACs were addressed, including the Swiss NAC - and their response will be among the others. It is later introduced by the Clinical and Laboratory Standards Institute (CLSI), primarily for antifungal susceptibility testing, but later also for a few antibacterial agents: cefepime, CLSI M100-S14 (2014) and subsequently ceftaroline and daptomycin. [Extracted from the article]

Co-resistance involves transfer of several genes into the same bacteria and/or the acquisition of mutations in different genetic loci affecting different antimicrobials whereas pleiotropic resistance implies the same genetic event affecting several antimicrobials. There is an increasing prevalence of isolates with co-resistance which are over-represented within the so-called high-risk clones. Compensatory events avoid fitness cost of co-resistance, even in the absence of antimicrobials. Nevertheless, they might be selected by different antimicrobials and a single agent might select co-resistant isolates. This process, named as co-selection, is not avoided with cycling or mixing strategies of antimicrobial use. Co-resistance and co-selection processes increase the opportunity for persistence of the bacteria and resistance genes and should be considered when designing strategies for decreasing antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Within a susceptible wild-type population, a small fraction of cells, even <10−9, is not affected when challenged by an antimicrobial agent. This subpopulation has mutations that impede antimicrobial action, allowing their selection during clinical treatment. Emergence of resistance occurs in the frame of a selective compartment termed a mutant selection window (MSW). The lower margin corresponds to the minimum inhibitory concentration of the susceptible cells, whereas the upper boundary, named the mutant prevention concentration (MPC), restricts the growth of the entire population, including that of the resistant mutants. By combining pharmacokinetic/pharmacodynamic concepts and an MPC strategy, the selection of resistant mutants can be limited. Early treatment avoiding an increase of the inoculum size as well as a regimen restricting the time within the MSW can reduce the probability of emergence of the resistant mutants. Physiological and, possibly, genetic adaptation in biofilms and a high proportion of mutator clones that may arise during chronic infections influence the emergence of resistant mutants. Moreover, a resistant population can emerge in a specific selective compartment after acquiring a resistance trait by horizontal gene transfer, but this may also be avoided to some extent when the MPC is reached. Known linkage between antimicrobial use and resistance should encourage actions for the design of antimicrobial treatment regimens that minimize the emergence of resistance. Emergence of a resistant bacterial subpopulation within a susceptible wild-type population can be restricted with a regimen using an antibiotic dose that is sufficiently high to inhibit both susceptible and resistant bacteria [ABSTRACT FROM AUTHOR]

Nosocomial infections caused by enterococci present a challenge for clinicians because treatment options are often limited due to the widespread occurrence of strains resistant to multiple antibiotics, including vancomycin. Daptomycin is a first-in-class cyclic lipopeptide that has proven efficacy for the treatment of Gram-positive infections. Although methicillin-resistant Staphylococcus aureus has been the most prominent target in the clinical development of daptomycin, this agent has demonstrated potent bactericidal activity in enterococcal infection models and has been used for the treatment of enterococcal infections in humans. In recent years, large-scale susceptibility studies have shown that daptomycin is active against >98% of enterococci tested, irrespective of their susceptibility to other antibacterial agents. This lack of cross-resistance reflects the fact that daptomycin has a mode of action distinct from those of other antibiotics, including glycopeptides. While there are limited data available from randomized controlled trials, extensive clinical experience with daptomycin in enterococcal infections (including bacteraemia, endocarditis, skin and soft tissue infections, bone and joint infections and urinary tract infections) has been reported. This growing body of evidence provides useful insights regarding the efficacy of daptomycin against enterococci in clinical settings. [ABSTRACT FROM PUBLISHER]

Abstract: The antibacterial susceptibilities of 6646 Streptococcus pneumoniae isolates collected in 38 countries from patients ≥65 years of age with community-acquired respiratory tract infections (RTIs) during years 1–5 of the PROTEKT study (1999–2004) were analysed. Rates of erythromycin resistance (36.0%), penicillin non-susceptibility (31.3%; 20.2% resistant plus 11.1% intermediately susceptible) and resistance to multiple antibacterials (37.2%) were stable over the 5 years. The most common macrolide resistance mechanism was erm(B) (61.4%); erm(B)+ mef(A) strains increased from 5.4% (year 1) to 7.4% (year 5) (P =0.037). Overall, 37.2% of isolates exhibited resistance to two or more antibacterials, including 15.9% resistant to both penicillin and erythromycin. Antibacterial resistance was highest in the Far East. Telithromycin resistance was rare (0.12%). Appropriate alternative empirical first-line therapies may be required for treating community-acquired RTIs in the elderly. [Copyright &y& Elsevier]

In the past decade CTX-M enzymes have become the most prevalent extended-spectrum β-lactamases, both in nosocomial and in community settings. The insertion sequences (ISs) ISEcp1 and ISCR1 (formerly common region 1 [CR1] or orf513) appear to enable the mobilization of chromosomal β-lactamase Kluyvera species genes, which display high homology with bla CTX-Ms. These ISs are preferentially linked to specific genes: ISEcp1 to most bla CTX-Ms, and ISCR1 to bla CTX-M-2 or bla CTX-M-9. The bla CTX-M genes embedded in class 1 integrons bearing ISCR1 are associated with different Tn402-derivatives, and often with mercury Tn21-like transposons. The bla CTX-M genes linked to ISEcp1 are often located in multidrug resistance regions containing different transposons and ISs. These structures have been located in narrow and broad host-range plasmids belonging to the same incompatibility groups as those of early antibiotic resistance plasmids. These plasmids frequently carry aminoglycoside, tetracycline, sulfonamide or fluoroquinolone resistance genes [qnr and/or aac(6′)-Ib-cr], which would have facilitated the dissemination of bla CTX-M genes because of co-selection processes. In Escherichia coli, they are frequently carried in well-adapted phylogenetic groups with particular virulence-factor genotypes. Also, dissemination has been associated with different clones (CTX-M-9 or CTX-M-14 producers) or epidemic clones associated with specific enzymes such as CTX-M-15. All these events might have contributed to the current pandemic CTX-M β-lactamase scenario. [Copyright &y& Elsevier]

Objectives Despite the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators, Pseudomonas aeruginosa is still a major pathogen in people with cystic fibrosis (pwCF). We determine the activity of cefiderocol and comparators in a collection of 154 P. aeruginosa isolates recovered from pwCF during three multicentre studies performed in 17 Spanish hospitals in 2013, 2017 and 2021. Methods ISO broth microdilution was performed and MICs were interpreted with CLSI and EUCAST criteria. Mutation frequency and WGS were also performed. Results Overall, 21.4% were MDR, 20.8% XDR and 1.3% pandrug-resistant (PDR). Up to 17% of the isolates showed a hypermutator phenotype. Cefiderocol demonstrated excellent activity; only 13 isolates (8.4%) were cefiderocol resistant by EUCAST (none using CLSI). A high proportion of the isolates resistant to ceftolozane/tazobactam (71.4%), meropenem/vaborbactam (70.0%), imipenem/relebactam (68.0%) and ceftazidime/avibactam (55.6%) were susceptible to cefiderocol. Nine out of 13 cefiderocol-resistant isolates were hypermutators (P  < 0.001). Eighty-three STs were detected, with ST98 being the most frequent. Only one isolate belonging to the ST175 high-risk clone carried bla VIM-2. Exclusive mutations affecting genes involved in membrane permeability, AmpC overexpression (L320P-AmpC) and efflux pump up-regulation were found in cefiderocol-resistant isolates (MIC = 4–8 mg/L). Cefiderocol resistance could also be associated with mutations in genes related to iron uptake (tonB -dependent receptors and pyochelin/pyoverdine biosynthesis). Conclusions Our results position cefiderocol as a therapeutic option in pwCF infected with P. aeruginosa resistant to most recent β-lactam/β-lactamase inhibitor combinations. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa , a ubiquitous opportunistic pathogen considered one of the paradigms of antimicrobial resistance, is among the main causes of hospital-acquired and chronic infections associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial resistance through chromosomal mutations, the increasing prevalence of transferable resistance determinants (such as the carbapenemases and the extended-spectrum β-lactamases), and the global expansion of epidemic lineages. The general objective of this initiative is to provide a comprehensive update of P. aeruginosa resistance mechanisms, especially for the extensively drug-resistant (XDR)/difficult-to-treat resistance (DTR) international high-risk epidemic lineages, and how the recently approved β-lactams and β-lactam/β-lactamase inhibitor combinations may affect resistance mechanisms and the definition of susceptibility profiles. To address this challenge, the European Study Group for Antimicrobial Resistance Surveillance (ESGARS) from the European Society of Clinical Microbiology and Infectious Diseases launched the 'Improving Surveillance of Antibiotic-Resistant Pseudomonas aeruginosa in Europe (ISARPAE)' initiative in 2022, supported by the Joint programming initiative on antimicrobial resistance network call and included a panel of over 40 researchers from 18 European Countries. Thus, a ESGARS-ISARPAE position paper was designed and the final version agreed after four rounds of revision and discussion by all panel members. To provide an update on (a) the emerging resistance mechanisms to classical and novel anti-pseudomonal agents, with a particular focus on β-lactams, (b) the susceptibility profiles associated with the most relevant β-lactam resistance mechanisms, (c) the impact of the novel agents and resistance mechanisms on the definitions of resistance profiles, and (d) the globally expanding XDR/DTR high-risk lineages and their association with transferable resistance mechanisms. The evidence presented herein can be used for coordinated epidemiological surveillance and decision making at the European and global level. [ABSTRACT FROM AUTHOR]

To assess the mortality attributable to infections caused by carbapenem-resistant Enterobacterales (CRE) and to investigate the effect of clinical management on differences in observed outcomes in a multinational matched cohort study. A prospective matched-cohorts study (NCT02709408) was performed in 50 European hospitals from March 2016 to November 2018. The main outcome was 30-day mortality with an active post-discharge follow-up when applied. The CRE cohort included patients with complicated urinary tract infections, complicated intra-abdominal infections, pneumonia, or bacteraemia from other sources because of CRE. Two control cohorts were selected: patients with infection caused by carbapenem-susceptible Enterobacterales (CSE) and patients without infection. Matching criteria included type of infection for the CSE group, hospital ward of CRE detection, and duration of hospital admission up to CRE detection. Multivariable and stratified Cox regression was applied. The cohorts included 235 patients with CRE infection, 235 patients with CSE infection, and 705 non-infected patients. The 30-day mortality (95% CI) was 23.8% (18.8–29.6), 10.6% (7.2–15.2), and 8.4% (6.5–10.6), respectively. The difference in 30-day mortality rates between patients with CRE infection when compared with patients with CSE infection was 13.2% (95% CI, 6.3–20.0), (HR, 2.57; 95% CI, 1.55–4.26; p < 0.001), and 15.4% (95% CI, 10.5–20.2) when compared with non-infected patients (HR, 3.85; 95% CI, 2.57–5.77; p < 0.001). The population attributable fraction for 30-day mortality for CRE vs. CSE was 19.28%, and for CRE vs. non-infected patients was 9.61%. After adjustment for baseline variables, the HRs for mortality were 1.87 (95% CI, 0.99–3.50; p 0.06) and 3.65 (95% CI, 2.29–5.82; p < 0.001), respectively. However, when treatment-related time-dependent variables were added, the HR of CRE vs. CSE reduced to 1.44 (95% CI, 0.78–2.67; p 0.24). CRE infections are associated with significant attributable mortality and increased adjusted hazard of mortality when compared with CSE infections or patients without infection. Underlying patient characteristics and a delay in appropriate treatment play an important role in the CRE mortality. [ABSTRACT FROM AUTHOR]

Purpose: To characterize the resistance mechanisms affecting the cefepime-taniborbactam combination in a collection of carbapenemase-producing Enterobacterales (CPE) and carbapenem-resistant Pseudomonas spp. (predominantly P. aeruginosa; CRPA) clinical isolates. Methods: CPE (n = 247) and CRPA (n = 170) isolates were prospectively collected from patients admitted to 8 Spanish hospitals. Susceptibility to cefepime-taniborbactam and comparators was determined by broth microdilution. Cefepime-taniborbactam was the most active agent, inhibiting 97.6% of CPE and 67.1% of CRPA (MICs ≤ 8/4 mg/L). All isolates with cefepime-taniborbactam MIC > 8/4 mg/L (5 CPE and 52 CRPA) and a subset with MIC ≤ 8/4 mg/L (23 CPE and 24 CRPA) were characterized by whole genome sequencing. Results: A reduced cefepime-taniborbactam activity was found in two KPC-ST307-Klebsiella pneumoniae isolates with altered porins [KPC-62-K. pneumoniae (OmpA, OmpR/EnvZ), KPC-150-K. pneumoniae (OmpK35, OmpK36)] and one each ST133-VIM-1-Enterobacter hormaechei with altered OmpD, OmpR, and OmpC; IMP-8-ST24-Enterobacter asburiae; and NDM-5-Escherichia coli with an YRIN-inserted PBP3 and a mutated PBP2. Among the P. aeruginosa (68/76), elevated cefepime-taniborbactam MICs were mostly associated with GES-5-ST235, OXA-2+VIM-2-ST235, and OXA-2+VIM-20-ST175 isolates also carrying mutations in PBP3, efflux pump (mexR, mexZ) and AmpC (mpl) regulators, and non-carbapenemase-ST175 isolates with AmpD-T139M and PBP3-R504C mutations. Overall, accumulation of these mutations was frequently detected among non-carbapenemase producers. Conclusions: The reduced cefepime-taniborbactam activity among the minority of isolates with elevated cefepime-taniborbactam MICs is not only due to IMP carbapenemases but also to the accumulation of multiple resistance mechanisms, including PBP and porin mutations in CPE and chromosomal mutations leading to efflux pumps up-regulation, AmpC overexpression, and PBP modifications in P. aeruginosa. [ABSTRACT FROM AUTHOR]

Persons living or working in nursing homes faced a higher risk of SARS-CoV-2 infections during the pandemic, resulting in heightened morbidity and mortality among older adults despite robust vaccination efforts. This prospective study evaluated the humoral and cellular immunity in fully vaccinated residents and workers from two nursing homes in Madrid, Spain, from 2020 to 2021. Measurements of IgG levels were conducted in August 2020 (pre-vaccination) and June and September 2021 (post-vaccination), alongside assessments of neutralizing antibodies and cellular responses in September 2021 among the most vulnerable individuals. Follow-up extended until February 2022 to identify risk factors for SARS-CoV-2 infection or mortality, involving 267 residents (mean age 87.6 years, 81.3% women) and 302 workers (mean age 50.7 years, 82.1% women). Residents exhibited a significantly higher likelihood of experiencing COVID-19 before June 2021 compared with nursing staff (OR [95% CI], 7.2 [3.0 to 17.2], p < 0.01). Participants with a history of previous COVID-19 infection showed more significant increases in IgG levels in August 2020, June 2021 and September 2021, alongside an increased proportion of neutralizing antibodies in the most vulnerable individuals. However, IgG decay remained the same between June and September 2021 based on the previous COVID-19 status. During the Omicron variant wave, residents and staff showed a similar rate of SARS-CoV-2 infection. Notably, preceding clinical or immunological factors before receiving three vaccination doses did not demonstrate associations with COVID-19 infection or overall mortality in our participant cohort. [ABSTRACT FROM AUTHOR]

Community-acquired pneumonia represents the third-highest cause of mortality in industrialized countries and the first due to infection. Although guidelines for the approach to this infection model are widely implemented in international health schemes, information continually emerges that generates controversy or requires updating its management. This paper reviews the most important issues in the approach to this process, such as an aetiologic update using new molecular platforms or imaging techniques, including the diagnostic stewardship in different clinical settings. It also reviews both the Intensive Care Unit admission criteria and those of clinical stability to discharge. An update in antibiotic, in oxygen, or steroidal therapy is presented. It also analyzes the management out-of-hospital in CAP requiring hospitalization, the main factors for readmission, and an approach to therapeutic failure or rescue. Finally, the main strategies for prevention and vaccination in both immunocompetent and immunocompromised hosts are reviewed. [ABSTRACT FROM AUTHOR]

Objectives To assess the microbiological characteristics of Escherichia coli causing healthcare-associated bacteraemia of urinary origin (HCA-BUO) in Spain (ITUBRAS-2 project), with particular focus on ESBL producers and isolates belonging to ST131 high-risk clone (HiRC). Clinical characteristics and outcomes associated with ST131 infection were investigated. Methods A total of 222 E. coli blood isolates were prospectively collected from patients with HCA-BUO from 12 tertiary-care hospitals in Spain (2017–19). Antimicrobial susceptibility and ESBL/carbapenemase production were determined. ST131 subtyping was performed. A subset of 115 isolates were selected for WGS to determine population structure, resistome and virulome. Clinical charts were reviewed. Results ESBL-producing E. coli prevalence was 30.6% (68/222). ST131 represented 29.7% (66/222) of E. coli isolates and accounted for the majority of ESBL producers (46/68, 67.6%). The C2/H30-Rx subclone accounted for most ST131 isolates (44/66) and was associated with CTX-M-15 (37/44) and OXA-1 enzymes (27/44). Cluster C1-M27 was identified in 4/10 isolates belonging to subclade C1/H30-R1 and associated with CTX-M-27. Additionally, ST131 isolates showed a high content of other acquired resistance genes, and clade C/ST131 isolates carried characteristic QRDR mutations. They were categorized as uropathogenic E. coli and had higher aggregate virulence scores. ST131 infection was associated with more complex patients, prior use of cephalosporins and inadequate empirical treatment but was not associated with worse clinical outcomes. Conclusions ST131 HiRC is the main driver of ESBL-producing E. coli causing HCA-BUO in Spain, mainly associated with the expansion of subclade CTX-M-15-C2/H30-Rx and the emergence of CTX-M-27-C1/H30-R1 (Cluster C1-M27). [ABSTRACT FROM AUTHOR]

A response by Rafael Cantón and colleagues to a letter to the editor about their article "A Potential Role for Daptomycin in Enterococcal Infections: What is the Evidence?" in the 2010 issue is presented.

Objectives Ceftazidime/avibactam and cefiderocol are two of the latest antibiotics with activity against a wide variety of Gram-negatives, including carbapenem-resistant Enterobacterales. We sought to describe the phenotypic and genotypic characteristics of ceftazidime/avibactam- and cefiderocol-resistant KPC- Klebsiella pneumoniae (KPC- Kp) detected during an outbreak in 2020 in the medical ICU of our hospital. Methods We collected 11 KPC- Kp isolates (6 clinical; 5 surveillance samples) resistant to ceftazidime/avibactam and cefiderocol from four ICU patients (November 2020 to January 2021), without prior exposure to these agents. All patients had a decontamination regimen as part of the standard ICU infection prevention protocol. Additionally, one ceftazidime/avibactam- and cefiderocol-resistant KPC- Kp (June 2019) was retrospectively recovered. Antibiotic susceptibility was determined by broth microdilution. β-Lactamases were characterized and confirmed. WGS was also performed. Results All KPC- Kp isolates (ceftazidime/avibactam MIC  ≥16/4 mg/L; cefiderocol MIC ≥4 mg/L) were KPC + CTX-M-15 producers and belonged to the ST307 high-risk-clone (ST307-HRC). KPC-62 (L168Q) was detected in all isolates involved in the 2020 outbreak, contained in January 2021. KPC-31 (D179Y) was identified in the KPC- Kp from 2019. Cloning experiments demonstrated that both bla KPC-62 and bla KPC-31 were responsible for ceftazidime/avibactam resistance (MIC >16 mg/L) and an increased cefiderocol MIC. Additionally, mutations in OmpA and EnvZ/OmpR porin proteins (in KPC-62- Kp) and in PBP2 (in KPC-31- Kp) were found and may be involved in cefiderocol resistance. Conclusions The emergence of resistance to both ceftazidime/avibactam and cefiderocol in KPC- Kp -HRCs, together with the diversification of novel KPC enzymes displaying different antibiotic resistance phenotypes, is an epidemiological and clinical risk. [ABSTRACT FROM AUTHOR]

Although the spectrumof fungal pathology has been studied extensively in immunosuppressed patients, little is known about the epidemiology, risk factors, and management of fungal infections in chronic pulmonary diseases like bronchiectasis. In bronchiectasis patients, deteriorated mucociliary clearance--generally due to prior colonization by bacterial pathogens--and thick mucosity propitiate, the persistence of fungal spores in the respiratory tract. The most prevalent fungi in these patients are Candida albicans and Aspergillus fumigatus; these are almost always isolated with bacterial pathogens like Haemophillus influenzae and Pseudomonas aeruginosa, making very difficult to define their clinical significance. Analysis of the mycobiome enables us to detect a greater diversity of microorganisms than with conventional cultures. The results have shown a reduced fungal diversity in most chronic respiratory diseases, and that this finding correlates with poorer lung function. Increased knowledge of both the mycobiome and the complex interactions between the fungal, viral, and bacterial microbiota, including mycobacteria, will further our understanding of the mycobiome's relationship with the pathogeny of bronchiectasis and the development of innovative therapies to combat it. [ABSTRACT FROM AUTHOR]

Phage tail-like bacteriocins (PTLBs) are large proteomic structures similar to the tail phages. These structures function in bacterial competition by making pores in the membrane of their competitors. The PTLBs identified in Pseudomonas aeruginosa are known as R-type and F-type pyocins, which have a narrow spectrum of action. Their specificity is determined by the tail fiber and is closely related to the lipopolysaccharide type of the target competitor strain. In this study, the genome sequences of 32 clinical of P. aeruginosa clinical isolates were analysed to investigate the presence of R-type and F-type pyocins, and one was detected in all strains tested. The pyocins were classified into 4 groups on the basis of the tail fiber and also the homology, phylogeny and structure of the cluster components. A relationship was established between these groups and the sequence type and serotype of the strain of origin and finally the killing spectrum of the representative pyocins was determined showing a variable range of activity between 0 and 37.5%. The findings showed that these pyocins could potentially be used for typing of P. aeruginosa clinical isolates, on the basis of their genomic sequence and cluster structure, and also as antimicrobial agents. [ABSTRACT FROM AUTHOR]

Objectives: To detect a potential hidden dissemination of the blaOXA-48 gene among Proteus mirabilis isolates obtained from a single centre.Methods: P. mirabilis from diverse clinical samples presenting an ESBL phenotype or obtained from blood cultured from 2017 to 2019 were evaluated. Bacterial identification was performed using MALDI-TOF MS. MICs were determined using International Organization for Standardization (ISO) standard microdilution and interpreted following EUCAST guidelines. WGS was performed using both short- and long-read technologies and assemblies were done using Unicycler. Resistomes were assessed using the ResFinder database. SNPs were detected using the PATRIC bioinformatics platform. Cloning experiments were performed using the pCRII-TOPO cloning kit.Results: Thirty-one out of 108 (28.7%) isolates were positive for blaOXA-48 and blaCTX-M-15. Twenty-nine out of 31 of the isolates were susceptible to temocillin, piperacillin/tazobactam, ertapenem and meropenem, whereas only 2/31 showed a resistance phenotype against these antibiotics. Both blaOXA-48 and blaCTX-M-15 genes were detected within the same chromosomally integrated new transposon in all isolates. The resistant isolates displayed a single mutation located in the putative promoter upstream of blaOXA-48. Cloning experiments confirmed that the mutation was responsible for the resistance phenotype.Conclusions: The presence of a chromosomal copy of blaOXA-48 did not confer resistance to carbapenems, but a single mutation in the promoter could lead to an increase in resistance. This study shows a hidden circulation of OXA-48-positive, but carbapenem- and piperacillin/tazobactam-susceptible, P. mirabilis isolates that can become resistant to β-lactams after a single mutation. [ABSTRACT FROM AUTHOR]

Abstract: Two of the most serious respiratory tract infections are community-acquired pneumonia (CAP) and acute exacerbations of chronic bronchitis (AECB). The most common pathogens found in patients with these infections are Haemophilus influenzae and Streptococcus pneumoniae. Pseudomonas aeruginosa is also relatively common, particularly in elderly patients with AECB. S. pneumoniae and P. aeruginosa are also of concern in relation to the development of resistance to antimicrobial drugs. The administration of antibiotics at doses that result in concentrations exceeding the mutant prevention concentration at the site of infection is one strategy to prevent the development of drug-resistant pathogens. AECB is associated with a high risk of in-hospital mortality, particularly in patients treated in the intensive care unit. CAP is also associated with significant risks and often requires treatment under hospital supervision. Several patient-related factors help identify those patients who are most at risk of mortality and morbidity. Treatment should be tailored towards the severity of the disease. The fluoroquinolones, such as levofloxacin, are an effective treatment option for AECB and CAP. Compared with many other antibiotics, resistance to levofloxacin remains low for most infecting pathogens. The oral bioavailability of levofloxacin is over 99%, enabling simple switching from intravenous to oral therapy during treatment. It is also preferentially distributed to compartments in the lung, thus achieving high concentrations at the site of respiratory tract infections. Combined with cover of the major infecting pathogens found in patients with AECB and CAP, and a cost-effective treatment compared with many alternative therapies, levofloxacin is an attractive option for the treatment of at-risk patients with these respiratory tract infections. [Copyright &y& Elsevier]

In the face of increasing antimicrobial resistance and the paucity of new antimicrobial agents it has become clear that new antimicrobial strategies are urgently needed. One of these is to revisit old antibiotics to ensure that they are used correctly and to their full potential, as well as to determine whether one or several of them can help alleviate the pressure on more recent agents. Strategies are urgently needed to 're-develop' these drugs using modern standards, integrating new knowledge into regulatory frameworks and communicating the knowledge fromthe research bench to the bedside.Without a systematic approach to re-developing these old drugs and rigorously testing them according to today's standards, there is a significant risk of doing harm to patients and further increasing multidrug resistance. This paper describes factors to be considered and outlines steps and actions needed to re-develop old antibiotics so that they can be used effectively for the treatment of infections. [ABSTRACT FROM AUTHOR]

• Only a subset of European centres routinely conducted susceptibility testing for new antibiotics, characterised the AmpC overproduction resistance mechanism, and provided identification of carbapenemase enzymes in ESCPM species. • ESCPM species displayed third-, combined third- and fourth-generation cephalosporins, and carbapenems resistance phenotypes in 15.7%, 4.6%, and 9.5% of the isolates, respectively. • ESBL expression, AmpC overproduction, and carbapenemase production were detected in 6.4%, 15.8%, and 3.1% of the isolates, respectively. • E. cloacae complex and S. marcescens emerged as the most frequently detected species , with the former displaying ESBL production, AmpC overproduction and carbapenemase production in 11.4%, 17.1%, and 3.5% of the isolates, respectively. • Klebsiella aerogenes showed the highest rate of both 3GC resistant phenotype (29.8%) and AmpC overproduction (32.1%), while providencia species those of both carbapenems resistance phenotype (42.7%) and carbapenemase production (29.4%). • Among carbapenemases, VIM and OXA-48 enzymes were the most frequently identified in ESCPM species. • Although its use as monotherapy is discouraged, colistin emerged as the most active drug against ESCPM species (except those intrinsically resistant) displaying both carbapenem resistance phenotype and carbapenemase production. The ESCPM group (Enterobacter species including Klebsiella aerogenes - formerly Enterobacter aerogenes, Serratia species, Citrobacter freundii complex, Providencia species and Morganella morganii) has not yet been incorporated into systematic surveillance programs. We conducted a multicentre retrospective observational study analysing all ESCPM strains isolated from blood cultures in 27 European hospitals over a 3-year period (2020–2022). Diagnostic approach, epidemiology, and antimicrobial susceptibility were investigated. Our study comprised 6,774 ESCPM isolates. MALDI-TOF coupled to mass spectrometry was the predominant technique for bacterial identification. Susceptibility to new β-lactam/β-lactamase inhibitor combinations and confirmation of AmpC overproduction were routinely tested in 33.3% and 29.6% of the centres, respectively. The most prevalent species were E. cloacae complex (44.8%) and S. marcescens (22.7%). Overall, third-generation cephalosporins (3GC), combined third- and fourth-generation cephalosporins (3GC + 4GC) and carbapenems resistance phenotypes were observed in 15.7%, 4.6%, and 9.5% of the isolates, respectively. AmpC overproduction was the most prevalent resistance mechanism detected (15.8%). Among carbapenemase-producers, carbapenemase type was provided in 44.4% of the isolates, VIM- (22.9%) and OXA-48-enzyme (16%) being the most frequently detected. E. cloacae complex, K. aerogenes and Providencia species exhibited the most notable cumulative antimicrobial resistance profiles, with the former displaying 3GC, combined 3GC + 4GC and carbapenems resistance phenotypes in 15.2%, 7.4%, and 12.8% of the isolates, respectively. K. aerogenes showed the highest rate of both 3GC resistant phenotype (29.8%) and AmpC overproduction (32.1%), while Providencia species those of both carbapenems resistance phenotype (42.7%) and carbapenemase production (29.4%). ESCPM isolates exhibiting both 3GC and combined 3GC + 4GC resistance phenotypes displayed high susceptibility to ceftazidime/avibactam (98.2% and 95.7%, respectively) and colistin (90.3% and 90.7%, respectively). Colistin emerged as the most active drug against ESCPM species (except those intrinsically resistant) displaying both carbapenems resistance phenotype (85.8%) and carbapenemase production (97.8%). This study presented a current analysis of ESCPM species epidemiology in Europe, providing insights to inform current antibiotic treatments and guide strategies for antimicrobial stewardship and diagnostics. [ABSTRACT FROM AUTHOR]

This work aimed to evaluate the predatory activity of Bdellovibrio bacteriovorus 109J on clinical isolates of Pseudomonas aeruginosa selected from well-characterized collections of cystic fibrosis (CF) lung colonization (n = 30) and bloodstream infections (BSI) (n = 48) including strains selected by genetic lineage (frequent and rare sequence types), antibiotic resistance phenotype (susceptible and multidrug-resistant isolates), and colony phenotype (mucoid and non-mucoid isolates). The intraspecies predation range (I-PR) was defined as the proportion of susceptible strains within the entire collection. In contrast, the predation efficiency (PE) is the ratio of viable prey cells remaining after predation compared to the initial inoculum. I-PR was significantly higher for CF (67%) than for BSI P. aeruginosa isolates (35%) probably related to an environmental origin of CF strains whereas invasive strains are more adapted to humans. I-PR correlation with bacterial features such as mucoid morphotype, genetic background, or antibiotic susceptibility profile was not detected. To test the possibility of increasing I-PR of BSI isolates, a polyhydroxyalkanoate depolymerase deficient B. bacteriovorus bd2637 mutant was used. Global median I-PR and PE values remained constant for both predators, but 31.2% of 109J-resistant isolates were susceptible to the mutant, and 22.9% of 109J-susceptible isolates showed resistance to predation by the mutant, pointing to a predator–prey specificity process. The potential use of predators in the clinical setting should be based on the determination of the I-PR for each species, and the PE of each particular target strain. [ABSTRACT FROM AUTHOR]

Background: The potential pathogenic role of Stenotrophomonas maltophilia in lung disease and in particular in cystic fibrosis is unclear. To develop further understanding of the biology of this taxa, the taxonomic position, antibiotic resistance and virulence factors of S. maltophilia isolates from patients with chronic lung disease were studied. Results: A total of 111 isolates recovered between 2003 and 2016 from respiratory samples from patients in five different countries were included. Based on a cut-off of 95%, analysis of average nucleotide identity by BLAST (ANIb) showed that the 111 isolates identified as S. maltophilia by Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) belonged to S. maltophilia (n = 65), S. pavanii (n = 6) and 13 putative novel species (n = 40), which each included 1–5 isolates; these groupings coincided with the results of the 16S rDNA analysis, and the L1 and L2 ß-lactamase Neighbor-Joining phylogeny. Chromosomally encoded aminoglycoside resistance was identified in all S. maltophilia and S. pavani isolates, while acquired antibiotic resistance genes were present in only a few isolates. Nevertheless, phenotypic resistance levels against commonly used antibiotics, determined by standard broth microbroth dilution, were high. Although putative virulence genes were present in all isolates, the percentage of positive isolates varied. The Xps II secretion system responsible for the secretion of the StmPr1–3 proteases was mainly limited to isolates identified as S. maltophilia based on ANIb, but no correlation with phenotypic expression of protease activity was found. The RPF two-component quorum sensing system involved in virulence and antibiotic resistance expression has two main variants with one variant lacking 190 amino acids in the sensing region. Conclusions: The putative novel Stenotrophomonas species recovered from patient samples and identified by MALDI-TOF/MS as S. maltophilia, differed from S. maltophilia in resistance and virulence genes, and therefore possibly in pathogenicity. Revision of the Stenotrophomonas taxonomy is needed in order to reliably identify strains within the genus and elucidate the role of the different species in disease. [ABSTRACT FROM AUTHOR]

The three main processes shaping the evolutionary ecology of antibiotic resistance (AbR) involve the emergence, invasion and occupation by antibiotic-resistant genes of significant environments for human health. The process of emergence in complex bacterial populations is a high-frequency, continuous swarming of ephemeral combinatory genetic and epigenetic explorations inside cells and among cells, populations and communities, expanding in different environments (migration), creating the stochastic variation required for evolutionary progress. Invasion refers to the process by which AbR significantly increases in frequency in a given (invaded) environment, led by external invaders local multiplication and spread, or by endogenous conversion. Conversion occurs because of the spread of AbR genes from an exogenous resistant clone into an established (endogenous) bacterial clone(s) colonizing the environment; and/or because of dissemination of particular resistant genetic variants that emerged within an endogenous clonal population. Occupation of a given environment by a resistant variant means a permanent establishment of this organism in this environment, even in the absence of antibiotic selection. Specific interventions on emergence influence invasion, those acting on invasion also influence occupation and interventions on occupation determine emergence. Such interventions should be simultaneously applied, as they are not simple solutions to the complex problem of AbR. [ABSTRACT FROM AUTHOR]

This study aimed to assess the ultrapure cannabidiol (CBD) antibacterial activity and to investigate the antibacterial activity of the combination CBD + polymyxin B (PB) against Gram-negative (GN) bacteria, including PB-resistant Gram-negative bacilli (GNB). We used the standard broth microdilution method, checkerboard assay, and time-kill assay. CBD exhibited antibacterial activity against Gram-positive bacteria, lipooligosaccharide (LOS)-expressing GN diplococcus (GND) (Neisseria gonorrhoeae, Neisseria meningitidis, Moraxella catarrhalis), and Mycobacterium tuberculosis, but not against GNB. For most of the GNB studied, our results showed that low concentrations of PB (≤ 2 µg/mL) allow CBD (≤ 4 µg/mL) to exert antibacterial activity against GNB (e.g., Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii), including PB-resistant GNB. CBD + PB also showed additive and/or synergistic effect against LOS-expressing GND. Time-kill assays results showed that the combination CBD + PB leads to a greater reduction in the number of colony forming units per milliliter compared to CBD and PB alone, at the same concentration used in combination, and the combination CBD + PB was synergistic for all four PB-resistant K. pneumoniae isolates evaluated. Our results show that CBD has translational potential and should be further explored as a repurposed antibacterial agent in clinical trials. The antibacterial efficacy of the combination CBD + PB against multidrug-resistant and extensively drug-resistant GNB, especially PB-resistant K. pneumoniae, is particularly promising. [ABSTRACT FROM AUTHOR]

Inhaled antibiotics are a common and valuable therapy for patients suffering from chronic lung infection, with this particularly well demonstrated for patients with cystic fibrosis. However, in vitro tests to predict patient response to inhaled antibiotic therapy are currently lacking. There are indications that antimicrobial susceptibility testing (AST) may have a role in guidance of therapy, but which tests would correlate best still needs to be researched in clinical studies or animal models. Applying the principles of European Committee on Antimicrobial Susceptibility Testing methodology, the analysis of relevant and reliable data correlating different AST tests to patients' outcomes may yield clinical breakpoints for susceptibility, but these data are currently unavailable. At present, we believe that it is unlikely that standard determination of minimum inhibitory concentration will prove the best predictor. [ABSTRACT FROM AUTHOR]

Gold nanotriangles (AuNTs) functionalized with dithiolated oligonucleotides have been employed to develop an amplification-free electrochemical biosensor for SARS-CoV-2 in patient samples. Gold nanotriangles, prepared through a seed-mediated growth method and exhaustively characterized by different techniques, serve as an improved electrochemical platform and for DNA probe immobilization. Azure A is used as an electrochemical indicator of the hybridization event. The biosensor detects either single stranded DNA or RNA sequences of SARS-CoV-2 of different lengths, with a low detection limit of 22.2 fM. In addition, it allows to detect point mutations in SARS-CoV-2 genome with the aim to detect more infective SARS-CoV-2 variants such as Alpha, Beta, Gamma, Delta, and Omicron. Results obtained with the biosensor in nasopharyngeal swab samples from COVID-19 patients show the possibility to clearly discriminate between non-infected and infected patient samples as well as patient samples with different viral load. Furthermore, the results correlate well with those obtained by the gold standard technique RT-qPCR, with the advantage of avoiding the amplification process and the need of sophisticated equipment. [ABSTRACT FROM AUTHOR]

In this work we describe a highly sensitive method based on a biocatalyzed electrochemiluminescence approach. The system combines, for the first time, the use of few-layer bismuthene (FLB) as a platform for the oriented immobilization of tetrahedral DNA nanostructures (TDNs) specifically designed and synthetized to detect a specific SARS-CoV-2 gene sequence. In one of its vertices, these TDNs contain a DNA capture probe of the open reading frame 1 ab (ORF1ab) of the virus, available for the biorecognition of the target DNA/RNA. At the other three vertices, there are thiol groups that enable the stable anchoring/binding to the FLB surface. This novel geometry/approach enables not only the binding of the TDNs to surfaces, but also the orientation of the capture probe in a direction normal to the bismuthine surface so that it is readily accessible for binding/recognition of the specific SARS-CoV-2 sequence. The analytical signal is based on the anodic electrochemiluminescence (ECL) intensity of luminol which, in turn, arises as a result of the reaction with H 2 O 2 , generated by the enzymatic reaction of glucose oxidation, catalyzed by the biocatalytic label avidin-glucose oxidase conjugate (Av-GOx), which acts as co-reactant in the electrochemiluminescent reaction. The method exhibits a limit of detection (LOD) of 4.31 aM and a wide linear range from 14.4 aM to 1.00 μM, and its applicability was confirmed by detecting SARS-CoV-2 in nasopharyngeal samples from COVID-19 patients without the need of any amplification process. [Display omitted] • Synthesis and characterization of tetrahedral DNA nanostructures and few-layer bismuthene. • Performance of an Electrochemiluminescent DNA biosensor for SARS-CoV-2 detection. • Detection of COVID-19 patients directly in nasopharyngeal samples avoiding DNA amplification step. • DNA hybridization detection by ECL coupled to a biocatalytic reaction. [ABSTRACT FROM AUTHOR]

Carbapenemase-producing Enterobacterales (CPE) infections have been occasionally described in patients with coronavirus disease-19 (COVID-19). We assess the clinical features and outcome of these infections. In this retrospective single-centre, case-control study, we included 54 patients with CPE infection: 30 case-patients (COVID-19) and 24 controls (non-COVID-19), collected between March and May 2020. We compared the epidemiological, clinical features, and outcome between cases and controls. CPE infection was more frequent in COVID-19 patients than in controls (1.1 vs. 0.5%, p =.005). COVID-19 patients were younger, had a lower frequency of underlying diseases (p =.01), and a lower median Charlson score (p =.002). Predisposing factors such as antimicrobial use, mechanical ventilation, or ICU admission, were more frequent in COVID-19 patients (p <.05). There were 73 episodes of infection (42 cases and 31 controls) that were more frequently hospital-acquired and diagnosed at the ICU in COVID-19 patients (p <.001). Urinary tract was the most common source of infection (47.9%), followed by pneumonia (23.3%). The frequency of severe sepsis or shock (p =.01) as well as the median SOFA score (p =.04) was higher in cases than in controls. Klebsiella pneumoniae (80.8%), Serratia marcescens (11%) and Enterobacter cloacae (4.1%) were the most common bacteria in both groups (KPC 56.2%, OXA-48 26% and VIM 17.8%). Overall 30-d mortality rate of COVID-19 patients and controls was 30 and 16.7%, respectively (p =.25). COVID-19 patients have an increased risk of CPE infections, which usually present as severe, nosocomial infections, appearing in critically-ill patients and associated with a high mortality. [ABSTRACT FROM AUTHOR]

Membrane computing is a natural computing procedure inspired in the compartmental structure of living cells. This approach allows mimicking the complex structure of biological processes, and, when applied to transmissible diseases, can simulate a virtual 'epidemic' based on interactions between elements within the computational model according to established conditions. General and focused vaccination strategies for controlling SARS-Cov-2 epidemics have been simulated for 2.3 years from the emergence of the epidemic in a hypothetical town of 10320 inhabitants in a country with mean European demographics where COVID-19 is imported. The age and immunological-response groups of the hosts and their lifestyles were minutely examined. The duration of natural, acquired immunity influenced the results; the shorter the duration, the more endemic the process, resulting in higher mortality, particularly among elderly individuals. During epidemic valleys between waves, the proportion of infected patients belonging to symptomatic groups (mostly elderly) increased in the total population, a population that largely benefits from standard double vaccination, particularly with boosters. There was no clear difference when comparing booster shots provided at 4 or 6 months after standard double-dose vaccination. Vaccines even of moderate efficacy (short-term protection) were effective in decreasing the number of symptomatic cases. Generalized vaccination of the entire population (all ages) added little benefit to overall mortality rates, and this situation also applied for generalized lockdowns. Elderly-only vaccination and lockdowns, even without general interventions directed to reduce population transmission, is sufficient for dramatically reducing mortality. Membrane computing technology simulates the effect of generalized or focused vaccination and lockdown in a town with detailed demographic complexity, experiencing an in silico SARS-Cov-2 epidemic over the course of 2.3 years. [ABSTRACT FROM AUTHOR]

Introduction: Healthcare-associated (HCA) infections represent a growing public health problem. The aim of this study was to compare community-onset healthcare associated (CO-HCA) bacteremic urinary tract infections (BUTI) and hospital-acquired (HA)-BUTI with special focus on multidrug resistances (MDR) and outcomes. Methods: ITUBRAS-project is a prospective multicenter cohort study of patients with HCA-BUTI. All consecutive hospitalized adult patients with CO-HCA-BUTI or HA-BUTI episode were included in the study. Exclusion criteria were: patients < 18 years old, non-hospitalized patients, bacteremia from another source or primary bacteremia, non-healthcare-related infections and infections caused by unusual pathogens of the urinary tract. The main outcome variable was 30-day all-cause mortality with day 1 as the first day of positive blood culture. Logistic regression was used to analyze factors associated with clinical cure at hospital discharge and with receiving inappropriate initial antibiotic treatment. Cox regression was used to evaluate 30-day all-cause mortality. Results: Four hundred forty-three episodes were included, 223 CO-HCA-BUTI. Patients with CO-HCA-BUTI were older (p < 0.001) and had more underlying diseases (p = 0.029) than those with HA-BUTI. The severity of the acute illness (Pitt score) was also higher in CO-HCA-BUTI (p = 0.026). Overall, a very high rate of MDR profiles (271/443, 61.2%) was observed, with no statistical differences between groups. In multivariable analysis, inadequate empirical treatment was associated with MDR profile (aOR 3.35; 95% CI 1.77–6.35), Pseudomonas aeruginosa (aOR 2.86; 95% CI 1.27–6.44) and Charlson index (aOR 1.11; 95% CI 1.01–1.23). Mortality was not associated with the site of acquisition of the infection or the presence of MDR profile. However, in the logistic regression analyses patients with CO-HCA-BUTI (aOR 0.61; 95% CI 0.40–0.93) were less likely to present clinical cure. Conclusion: The rate of MDR infections was worryingly high in our study. No differences in MDR rates were found between CO-HCA-BUTI and HA-BUTI, in the probability of receiving inappropriate empirical treatment or in 30-day mortality. However, CO-HCA-BUTIs were associated with worse clinical cure. [ABSTRACT FROM AUTHOR]

A comparative analysis of the performance of the new selective chromogenic CHROMagar™-Serratia culture medium for detection and isolation of Serratia marcescens was undertaken. A total of 134 clinical isolates (95 S. marcescens with and without carbapenemase production and 39 non-S. marcescens isolates) and 96 epidemiological samples (46 rectal swabs and 50 from environmental surfaces) were studied. Diagnostic values when compared with CHROMagar™-Orientation medium were 96.8% sensitivity, 100% specificity, 100% positive predictive value and 88.5% negative predictive value. In conclusion, CHROMagar™-Serratia shows an excellent ability for differentiation of S. marcescens among clinical isolates and in environmental samples. [ABSTRACT FROM AUTHOR]

Antibiotic-resistant organisms enter into water environments from human and animal sources. These bacteria are able to spread their genes into water-indigenous microbes, which also contain resistance genes. On the contrary, many antibiotics from industrial origin circulate in water environments, potentially altering microbial ecosystems. Risk assessment protocols for antibiotics and resistant bacteria in water, based on better systems for antibiotics detection and antibiotic-resistance microbial source tracking, are starting to be discussed. Methods to reduce resistant bacterial load in wastewaters, and the amount of antimicrobial agents, in most cases originated in hospitals and farms, include optimization of disinfection procedures and management of wastewater and manure. A policy for preventing mixing human-originated and animal-originated bacteria with environmental organisms seems advisable. [Copyright &y& Elsevier]

Objectives: To determine the activity of murepavadin in comparison with tobramycin, colistin and aztreonam, against cystic fibrosis (CF) Pseudomonas aeruginosa isolates growing in biofilms. The biofilm-epidemiological cut-off (ECOFF) values that include intrinsic resistance mechanisms present in biofilms were estimated.Methods: Fifty-three CF P. aeruginosa isolates from respiratory samples were tested using the Calgary (closed system) device, while 4 [2 clinical (one smooth, one mucoid) and 2 reference strains] were tested using the BioFlux, a microfluidic open model of biofilm testing. Biofilm was stained with SYTO9® and propidium iodide. The minimal biofilm inhibitory concentration (MBIC) and the minimal biofilm eradication concentration (MBEC) were determined. The MBIC-ECOFF and the MBEC-ECOFF were calculated.Results: Colistin, tobramycin and murepavadin presented similar MBIC50/MBIC90 values (4/32, 8/64 and 2/32, respectively). Murepavadin exhibited the lowest MBEC90 (64 mg/L). Aztreonam MBIC and MBEC values were higher than those of the other antibiotics tested. Tobramycin and murepavadin had the lowest MBEC-ECOFF (64 and 128 mg/L, respectively), while those of aztreonam and colistin exceeded 512 mg/L. Using the BioFlux, for the PAO1, PAO mutS and the smooth clinical strain, a significant difference (P < 0.0125) was observed when comparing the fluorescence of treated and untreated biofilms. For the mucoid strain, only the biofilm treated with aztreonam (MBIC and MBEC) and tobramycin (MBEC) showed differences with respect to the untreated biofilm.Conclusions: Murepavadin demonstrated good activity against P. aeruginosa biofilms both in open and closed systems. The MBIC-ECOFF and the MBEC-ECOFF are proposed as new parameters to estimate the activity of antibiotics on biofilms. [ABSTRACT FROM AUTHOR]

• Sepsis was more common in males than females • Males with sepsis presented higher disease severity than females • Sex did not affect mortality in patients with sepsis and admitted to intensive care units Men have been considered to have a higher incidence of infectious diseases, with controversy over the possibility that sex could influence the prognosis of the infection. This study aimed to explore this assumption in patients admitted to the intensive care unit (ICU) with septic bacteremia. A retrospective analysis (2006-2017) of septic patients with microbiologically confirmed bacteremia (n=440) was performed. Risk of ICU and in-hospital mortality in males versus females was compared by univariate analysis and a propensity score analysis integrating their clinical characteristics. Sepsis more frequently occurred in males (80.2% vs 76.1%) as well as in-hospital (48.0% vs 41.3%) and ICU (39.9% vs 36.5%) mortality. Univariate analyses showed that males had a higher Charlson comorbidity index and worse McCabe prognostic score. However, the propensity score in 296 matched patients demonstrated that females had higher risk of both ICU (OR 1.39; 95% CI 0.89-2.19) and in-hospital mortality (OR 1.18; 95% CI 0.77-1.83), but without statistical significance. Males with sepsis had worse clinical characteristics when admitted to the ICU, but sex had no influence on mortality. These data contribute to helping reduce the sex-dependent gap present in healthcare provision. [ABSTRACT FROM AUTHOR]

Purpose: to characterize the distribution and mechanisms involved in ceftolozane/tazobactam (C/T) resistance in Pseudomonas aeruginosa isolates recovered from intensive care units (ICUs) in Portugal as part of the STEP surveillance study. Materials and methods: a total of 226 P. aeruginosa isolates were collected from patients with low respiratory tract infections (LRTI) admitted to ICUs between June 2017 and July 2018. Susceptibility to antimicrobials including the recent C/T combination was determined by EUCAST-criteria. Whole genome sequencing (WGS) was performed in a subset of 17 isolates. Results: multidrug resistant (MDR) and extremely drug resistant (XDR) phenotypes accounted for 20.4% and 25.7% of cases, respectively. C/T showed the highest susceptibility rate in both MDR (100%) and XDR (93.1%) isolates, followed by amikacin (97.8% MDR and 79.3% XDR). bla KPC-3 (n  = 2) and bla GES-13 (n  = 1) carbapenemase genes were detected in 3 of the 17 sequenced isolates, but only the GES-13-producing isolate displayed resistance to C/T. Additionally, the C/T-resistant phenotype was also found in two non-carbapenemase producers that carried known ceftolozane/tazobactam resistance-associated mutations in the PBP3 gene. Conclusions: C/T was highly active against MDR/XDR- P. aeruginosa isolates causing LRTI in ICUs. Moreover, beyond carbapenemase-encoding genes, mutations in chromosomal PBP-encoding genes might also be involved in ceftolozane/tazobactam resistance in Portugal. [ABSTRACT FROM AUTHOR]

Carbapenemase production is constantly increasing among different Enterobacterales species. We analyzed the microbiological characteristics and population structure of all carbapenemase-producing Enterobacter spp. (CP-Ent) isolates recovered at the Ramón y Cajal Hospital between 2005 and 2018. Overall, 178 CP-Ent isolates (60.7% colonization, 39.3% clinical) were recovered from 165 hospitalized patients (165/176, 93.7%; medical [102/165], surgical [34/165], and intensive care unit [29/165] areas), emergency unit (4/176, 2.3%), and ambulatory patients (7/176, 4.0%). In addition, three CP-Ent were found in environmental sources. Clinical samples were mainly urine (37.1%). The most frequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-identified species were Enterobacter cloacae (n = 85) and Enterobacter asburiae (n = 49). hsp60 gene sequencing showed a higher species diversity than MALDI-TOF: 70 Enterobacter hormaechei-clusters III, VI, VIII; 69 Enterobacter roggenkampii-IV; 15 Enterobacter kobei-II; 9 E. asburiae-I; 3 Enterobacter ludwigii-V; and 1 E. cloacae subsp. dissolvens-XII. Nine Klebsiella aerogenes were also identified. Overall, a high clonal diversity (Simpson Diversity Index >0.90) was found among CP-Ent-clusters. Environmental isolates were clonally related to clinical ones. Amikacin and tigecycline showed the highest susceptibility (>93%). VIM-1 (n = 133/181, 73.5%) and OXA-48 (n = 34/181, 18.8%) carbapenemases were predominant, followed by KPC-2 (n = 9/181, 5.0%), KPC-3 (n = 2/181, 1.1%), VIM-2 (n = 1/181, 0.6%), and two coproducers (VIM-1+KPC-2 and VIM-1+KPC-3). Extended-spectrum beta-lactamase (ESBL) coproduction (14.4%) emerged in 2012, mainly associated with blaSHV-12 (p < 0.001), E. roggenkampii (p < 0.001), and colonization (p = 0.03). VIM-1- and OXA-48-CP-Ent fecal carriers increased in our hospital, particularly between 2011 and 2018 (p < 0.001). Moreover, KPC and OXA-48 producers emerged in 2010 and 2012, respectively. They superimposed over VIM producers, which were persistently recovered since first detection in 2005. These results depict increased complexity over time of CP-Ent. [ABSTRACT FROM AUTHOR]

The standard RT-PCR assay for coronavirus disease 2019 (COVID-19) is laborious and time-consuming, limiting testing availability. Rapid antigen-detection tests are faster and less expensive; however, the reliability of these tests must be validated before they can be used widely. The objective of this study was to determine the performance of the Panbio™ COVID-19 Ag Rapid Test Device (PanbioRT) (Abbott) in detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal swab specimens. This prospective multicentre study was carried out in ten Spanish university hospitals and included individuals with clinical symptoms or epidemiological criteria of COVID-19. Only individuals with ≤7 days from the onset of symptoms or from exposure to a confirmed case of COVID-19 were included. Two nasopharyngeal samples were taken to perform the PanbioRT as a point-of-care test and a diagnostic RT-PCR test. Among the 958 patients studied, 325 (90.5%) had true-positive results. The overall sensitivity and specificity for the PanbioRT were 90.5% (95%CI 87.5–93.6) and 98.8% (95%CI 98–99.7), respectively. Sensitivity in participants who had a threshold cycle (C T) < 25 for the RT-PCR test was 99.5% (95%CI 98.4–100), and in participants with ≤5 days of the clinical course it was 91.8% (95%CI 88.8–94.8). Agreement between techniques was 95.7% (κ score 0.90; 95%CI 0.88–0.93). The PanbioRT performs well clinically, with even more reliable results for patients with a shorter clinical course of the disease or a higher viral load. The results must be interpreted based on the local epidemiological context. [ABSTRACT FROM AUTHOR]

Background: Murepavadin, a novel peptidomimetic antibiotic, is being developed as an inhalation therapy for treatment of Pseudomonas aeruginosa respiratory infection in people with cystic fibrosis (CF). It blocks the activity of the LptD protein in P. aeruginosa causing outer membrane alterations.Objectives: To determine the in vitro activity of murepavadin against CF P. aeruginosa isolates and to investigate potential mechanisms of resistance.Methods: MIC values were determined by both broth microdilution and agar dilution and results compared. The effect of artificial sputum and lung surfactant on in vitro activity was also measured. Spontaneous mutation frequency was estimated. Bactericidal activity was investigated using time-kill assays. Resistant mutants were studied by WGS.Results: The murepavadin MIC50 was 0.125 versus 4 mg/L and the MIC90 was 2 versus 32 mg/L by broth microdilution and agar dilution, respectively. Essential agreement was >90% when determining in vitro activity with artificial sputum or lung surfactant. It was bactericidal at a concentration of 32 mg/L against 95.4% of the strains within 1-5 h. Murepavadin MICs were 2-9 two-fold dilutions higher for the mutant derivatives (0.5 to >16 mg/L) than for the parental strains. Second-step mutants were obtained for the PAO mutS reference strain with an 8×MIC increase. WGS showed mutations in genes involved in LPS biosynthesis (lpxL1, lpxL2, bamA2, lptD, lpxT and msbA).Conclusions: Murepavadin characteristics, such as its specific activity against P. aeruginosa, its unique mechanism of action and its strong antimicrobial activity, encourage the further clinical evaluation of this drug. [ABSTRACT FROM AUTHOR]

Objectives: The worldwide emergence of antibiotic resistance calls for effective exploitation of existing antibiotics. Antibiotic combinations with different modes of action can synergize for successful treatment. In the present study, we used microcalorimetry screening to identify synergistic combination treatments against clinical MDR isolates. The synergistic effects were validated in a murine infection model.Methods: The synergy of meropenem combined with colistin, rifampicin or amikacin was tested on 12 isolates (1 Escherichia coli, 5 Klebsiella pneumoniae, 3 Pseudomonas aeruginosa and 3 Acinetobacter baumannii) in an isothermal microcalorimeter measuring metabolic activity. One A. baumannii strain was tested with two individual pairings of antibiotic combinations. The microcalorimetric data were used to predict in vivo efficacy in a murine peritonitis/sepsis model. NMRI mice were inoculated intraperitoneally and after 1 h treated with saline, drug X, drug Y or X+Y. Bacterial load was determined by cfu in peritoneal fluid and blood after 4 h.Results: In vitro, of the 13 combinations tested on the 12 strains, 3 of them exhibited a synergistic reduction in MIC (23% n = 3/13), 5 showed an additive effect (38.5% n = 5/13) and 5 had indifferent or antagonistic effects (38.5% n = 5/13). There was a significant correlation (P = 0.024) between microcalorimetry-screening FIC index values and the log reduction in peritoneal fluid from mice that underwent combination treatment compared with the most effective mono treatment. No such correlation could be found between chequerboard and in vivo results (P = 0.16).Conclusions: These data support microcalorimetic metabolic readout to predict additive or synergistic effects of combination treatment of MDR infections within hours. [ABSTRACT FROM AUTHOR]

FASTinov® developed a rapid antimicrobial susceptibility test that includes the purification of a bacterial suspension directly from positive blood cultures (BC). In order to streamline laboratory workflow, the use of the bacterial suspension obtained through FASTinov® sample prep was tested for identification (ID) by matrix absorption laser deionization–time of flight mass spectrometry (MALDI-TOF MS) (Bruker) in 364 positive BC, and its accuracy assessed comparing with the MALDI-TOF MS ID of the next-day subcultured colonies. FASTinov sample prep was highly reliable for rapid ID directly from BC with proportion of agreement of 94.9% for Gram-positive and 96.3% for Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

Collateral sensitivity (CS) is a promising alternative approach to counteract the rising problem of antibiotic resistance (ABR). CS occurs when the acquisition of resistance to one antibiotic produces increased susceptibility to a second antibiotic. Recent studies have focused on CS strategies designed against ABR mediated by chromosomal mutations. However, one of the main drivers of ABR in clinically relevant bacteria is the horizontal transfer of ABR genes mediated by plasmids. Here, we report the first analysis of CS associated with the acquisition of complete ABR plasmids, including the clinically important carbapenem-resistance conjugative plasmid pOXA- 48. In addition, we describe the conservation of CS in clinical E. coli isolates and its application to selectively kill plasmid-carrying bacteria. Our results provide new insights that establish the basis for developing CS-informed treatment strategies to combat plasmid-mediated ABR. [ABSTRACT FROM AUTHOR]