Bacteremia Research Articles

Wearable nitric oxide-releasing antibacterial insert for preventing device-associated infections

Medical device-associated infections are a pervasive global healthcare concern, often leading to severe complications. Bacterial biofilms that form on indwelling medical devices, such as catheters, are significant contributors to infections like bloodstream and urinary tract infections. This study addresses the challenge of biofilms on medical devices by introducing a portable antimicrobial catheter insert (PACI) designed to be efficient, biocompatible, and anti-infective. The PACI utilizes nitric oxide (NO), known for its potent antimicrobial properties, to deter bacterial adhesion and biofilm formation. To achieve this, a photoinitiated NO donor, S-nitroso-N-acetylpenicillamine (SNAP), is covalently linked to a polydimethylsiloxane (PDMS) polymer. This design allows for higher NO loading for long-term impact and prevents premature donor leaching, a common challenge with SNAP-blended polymers. The SNAP-PDMS material was applied to a side-glowing fiber optic and connected to a wearable light module emitting 450 nm light, creating a functional antimicrobial insert. Activation of the fiber optic, accomplished with a one-click mechanism, enables real-time NO release, maintaining controlled NO levels for a minimum of 24 hours. The therapeutic levels of NO released via photocatalysis from the PACI demonstrated remarkable efficacy, with >90 % reduction in bacterial viability against S. aureus, S. epidermidis, and P. mirabilis without any cytotoxic impact on mammalian cells. This study underscores the potential of the NO-releasing insert in clinical settings, providing a portable and adaptable solution for preventing catheter-associated infections.

Short-term alcohol abstinence prior to liver transplantation and impact on rejection

Background & AimsAlcohol-associated liver disease (ALD) is a leading indication for liver transplant (LT). Historically, centers implemented 6-month abstinence periods prior to LT listing; however, the impact of this abstinence time on post-transplant rejection outcomes is unclear. This study evaluated if short-term abstinence is associated with increased rejection post-LT. MethodsThis single-center, retrospective, cohort included adult LT recipients from 11/1/2015 to 7/21/2021 with a primary indication of ALD. Patients were grouped by pre-transplant abstinence time of <6 or ≥6-months. The primary endpoint was biopsy proven acute rejection (BPAR) at 12-months post-LT. Secondary endpoints were infection, alcohol relapse, patient and graft survival at 12-months. ResultsOverall, 228 LT recipients met inclusion criteria (<6-months: n = 130; ≥6-months: n = 98). Patients with <6-months of abstinence were younger, had higher MELD scores, and more renal replacement therapy needs. Incidence of BPAR within 12 months of LT was 28 % in the <6-month group vs. 18 % in the ≥6-month group (p = 0.078). Tacrolimus initiation was lower at 7 days post-LT in the <6-month group (77% vs. 89 %; p = 0.029). Delay in tacrolimus initiation past 7 days post-LT was associated with greater BPAR (35% vs. 12 %; p = 0.0001). Increased bloodstream infections (21% vs. 7 %; p = 0.04) and CMV DNAemia (31% vs. 7 %; p = 0.0008) were seen in the <6-month group. Patient and graft survival was similar between groups. ConclusionsAbstinence time of <6-months was not associated with more BPAR within 12-months post-LT. The <6-month group was sicker at time of LT, which correlates to lower tacrolimus exposure early post-LT and heightened incidence of bacteremia and CMV viremia. Given the high acuity of the <6-month abstinence group, the risk of BPAR must be closely balanced with infection risk.

Antifungal Susceptibility Data and Epidemiological Distribution of Candida spp.: An In Vitro Five-Year Evaluation at University Hospital Policlinico of Catania and a Comprehensive Literature Review.

Invasive fungal infections represent a concerning healthcare issue, with Candida spp. reported as the main aetiological agent. Candida spp. bloodstream infections show high mortality rates, indicating increasing antifungal-resistance episodes as a contributing feature. Despite the global prevalence of C. albicans, non-albicans species emerged as significant in the last decades. The present manuscript reports a five-year evaluation on Candida spp. bloodstream isolates and their antifungal susceptibility profiles, aiming to enrich the literature and epidemiological data. According to the gathered data, antifungal-resistance cases remained uncommon. However, the study revealed rare resistance phenotypes such as a single case of pan-echinocandin resistance C. albicans. Finally, a comprehensive review of Candida spp. antifungal resistance integrates the data, emphasizing the extreme species-specific variability and the consequent importance of always providing species identification.

Carbapenem resistant Campylobacter jejuni bacteremia in a Bruton's X-linked agammaglobulinemia patient.

Immunocompromised patients are prone to recurrent Campylobacter infections. We report a case of recurrent multi-drug resistant Campylobactor jejuni bloodstream infections in a Bruton's X-linked agammaglobulinemia patient with prolonged ertapenem treatment. The isolate from the fifth recurrence developed carbapenem resistance, which is associated with mutations in a porin gene porA, and promoter changes and duplication of chromosomal blaOXA-61 gene. Combination therapy using cefepime and doxycycline (later switched to moxifloxacin) cleared the infection.

Prevalence and Outcomes of Candida auris Infections in a Tertiary Hospital in the United Arab Emirates (UAE).

Background Candida auris (C. auris) is an emerging serious threat to healthcare settings, with an average mortality of 45% in cases of bloodstream infections. This study aimed to determine the prevalence of C. auris in a single center in the UAEduring the year 2022 and understand risk factors related to poor outcomes. Methods This retrospective cohort chart review at Al-Qassimi Hospital encompassed all confirmed Candida infections, including C. auris, from January to December 2022. The study involved male and female patients aged 13 years and older, using comprehensive data extracted from the hospital's electronic healthcare records. The analysis included clinical, laboratory, and epidemiological data. Adhering to the 2011 Declaration of Helsinki and Good Pharmacoepidemiology Practices, the study received Institutional Review Board approval, with informed consent waived due to its retrospective design. Data were summarized using appropriate statistical methods, including the unpaired t-test, Mann-Whitney U test, Chi-square test, and Fisher exact test. A significance level of 95% (p<0.05) was maintained throughout the statistical analyses. Results Of the 75 confirmed Candidainfections, 53 (70.7%) were C. auris-positive cases.About 23 (43.4%) of the C. auris group were above 65 years old. Most cases of C. auris group were hospital-acquired (49, 92.5%). The highest number of positive cases were found in urine samples. The demographic and clinical profiles of the C. auris and non-auris groups candidemia were largely similar, except for differences in antifungal use history and ICU requirements. Notably, the C. auris group had a significantly lower history of antifungal use and a lower ICU requirement compared to the non-auris group. The study also highlighted the higher mortality rate associated with candidemia. While mortality was higher in the non-auris group, the difference was not statistically significant. Conclusions The findings of the study suggest that while C. auris poses a serious threat, particularly in hospital settings; the clinical and demographic factors influencing its spread and impact are complex and warrant further investigation. Understanding these factors is crucial for developing effective strategies to prevent and manage C. auris infections, particularly in vulnerable patient populations.

Impact of ESKAPE Pathogens on Bacteremia: A Three-Year Surveillance Study at a Major Hospital in Southern Italy.

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pose a serious public health threat as they are resistant to multiple antimicrobial agents. Bloodstream infections (BSIs) caused by ESKAPE bacteria have high mortality rates due to the limited availability of effective antimicrobials. This study aimed to evaluate the prevalence and susceptibility of ESKAPE pathogens causing BSIs over three years in a large tertiary hospital in Salerno. Conducted at the Clinical Microbiology Laboratory of San Giovanni di Dio e ''Ruggi D'Aragona'' Hospital from January 2020 to December 2022, blood culture samples from different departments were incubated in the BD BACTEC™ system for 5 days. Species identification was performed using MALDI-TOF MS, and antimicrobial resistance patterns were determined by the VITEK2 system. Out of 3197 species isolated from positive blood cultures, 38.7% were ESKAPE bacteria. Of these, 59.9% were found in blood culture samples taken from men, and the most affected age group was those aged >60 years. (70.6%). Staphylococcus aureus was the main BSI pathogen (26.3%), followed by Klebsiella pneumoniae (15.8%). Significant resistance rates were found, including 35% of Staphylococcus aureus being resistant to oxacillin and over 90% of Acinetobacter baumannii being resistant to carbapenems. These results highlight the urgent need for antimicrobial stewardship programs to prevent incurable infections.

A Study to Evaluate the Effectiveness of Health Education Program on Knowledge Regarding CLABSI on B.SC. Nursing Students Studying in Sharda University, Greater Noida, Uttar Pradesh

Introduction: Central line-associated bloodstream infection (CLABSI) When a central artery is infected with pathogens or viruses, it can be quite serious. Healthcare providers may put a central line into one of the larger veins to give medicines, fluids, or blood products, or draw blood for lab tests that people need over a long period. A CLABSI is a laboratory-confirmed bloodstream infection not found to be present or incubating on admission and the patient has had a central line in place for &gt; =2 calendar days by the day of the event, with that same organism also being RECOGNIZED from one other sterile site. Aim: The study aimed to determine the effectiveness of the health education program or knowledge regarding CLABSI. Methodology: A quasi-experimental pretest one-group and post-test design was adopted. In this situation, the population of the study, and the inclusion, and exclusion criteria were applied. Use of sample size, sampling techniques, validation, and data collection participants Population of the study included all B.Sc. Nursing undergraduate students at Sharda University School of Nursing. Research incurred from May to June 2024. A purposive sampling strategy was used in the selection and determination of the sample size of the study which was 60 students using the independent t-test formula. Result: The study shows that 68.3% of the participants must have a poor level of knowledge. 23.3% had an average level of knowledge 8.3% had a good level of knowledge regarding the pretest, a maximum of 63.3% they were having a good level of knowledge, about 26.7% of them are having an average level of knowledge, 10% of them had a poor level of knowledge regarding it. From the pre-test to the post-test the mean knowledge score has significantly increased, in the pre-test was 9.83 S. D= 4.00 and in the post-test, it iwas 15.65 and S. D= 3.99. The Paired T-test value is -8.85 and the p-value is less than 0.01. Conclusion: According to the findings, nursing students need to have a comprehensive grasp of CLABSI to build an understanding of the illness state and to receive proper treatment to prevent the development of other life-threatening disorders and sepsis.

Quantitative changes in platelet count in response to different pathogens: an analysis of patients with sepsis in both retrospective and prospective cohorts

Background Thrombocytopenia is commonly observed in patients with sepsis and is an independent risk factor for poor prognosis. However, the changes of platelet count caused by different pathogens can vary significantly. Our study aims to evaluate the quantitative changes in platelet count in response to various pathogens. Material and Methods We retrospectively analysed data of 3044 patients with sepsis from Medical Information Mart for Intensive Care (MIMIC, 2008–2019) database and prospectively collected data of 364 patients with sepsis from our local cohort of the Shandong Bloodstream Infection and Sepsis Collaboration Study (SBISC, 2020–2022). Propensity score matching (PSM) was employed to control for baseline differences in variables, except for the causative pathogen. Results Multivariate logistic analyses of both original and PSM populations identified Candida, Escherichia, Klebsiella, and Serratia species posing a higher risk for thrombocytopenia compared to others. Restricted cubic spline (RCS) curves showed L- or U-shaped associations between platelet count and 28-mortality with various cut-off values among different pathogens: ranging from 96 × 109/L in Candida species − 190 × 109/L in Klebsiella species. Conclusion Our present findings indicate a pathogen-specific effect on platelet count, highlighting the importance of monitoring thrombocytopenia in patients infected with above microorganisms. Clinicians need to consider pathogen-specific thresholds when intervene on platelet count.

Increased resistance rates of extended-spectrum β-lactamase-producing Enterobacterales isolated from blood cultures in Brazil

This study aimed to identify and evaluate the antimicrobial susceptibility profile of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales isolated from blood cultures of patients with suspected sepsis. This retrospective cross-sectional epidemiological study was performed for four years (2015 to 2018) by accessing the medical records of patients diagnosed with bloodstream infections in two tertiary public hospitals in Brazil. Culture results and susceptibility tests of bacterial strains isolated from blood samples were analyzed. During four years, 2,263 blood culture exams were performed, and Enterobacterales were isolated in 694 (30.7%) samples. The disk approximation test detected ESBL production in 171 (24.6%) of the 694 isolated Enterobacterales (p&lt;0.05), with 125 (73.1%) corresponding to Klebsiella spp., 28 (16.2%) to Escherichia coli, eight (4.6%) to Enterobacter spp., five (2.9%) to Serratia spp., three (1.7%) to Proteus spp., and two (1.2%) to Citrobacter spp. All tested antibiotics demonstrated low susceptibility (2.9% to 26.9%). The classes of monobactams, cephalosporins, and penicillin showed high resistance indices. The evaluated Enterobacterales isolates exhibited expressive antimicrobial resistance to drugs commonly used as empirical treatment in bloodstream infections. The findings reinforce the relevance of assessing the bacterial antimicrobial susceptibility profile, as it drives antibiotic therapy, potentially detecting multiresistance cases.

Getting rapid diagnostic test data into the appropriate hands by leveraging pharmacy staff and a clinical surveillance platform: a case study from a US community hospital

Abstract Objectives To outline the procedural implementation and optimization of rapid diagnostic test (RDT) results for bloodstream infections (BSIs) and to evaluate the combination of RDTs with real-time antimicrobial stewardship team (AST) support plus clinical surveillance platform (CSP) software on time to appropriate therapy in BSIs at a single health system. Methods Blood culture reporting and communication were reported for four time periods: (i) a pre-BCID [BioFire® FilmArray® Blood Culture Identification (BCID) Panel] implementation period that consisted of literature review and blood culture notification procedure revision; (ii) a BCID implementation period that consisted of BCID implementation, real-time results notification via CSP, and creation of a treatment algorithm; (iii) a post-BCID implementation period; and (iv) a BCID2 implementation period. Time to appropriate therapy metrics was reported for the BCID2 time period. Results The mean time from BCID2 result to administration of effective antibiotics was 1.2 h (range 0–7.9 h) and time to optimal therapy was 7.6 h (range 0–113.8 h) during the BCID2 Panel implementation period. When comparing time to optimal antibiotic administration among patients growing ceftriaxone-resistant Enterobacterales, the BCID2 Panel group (mean 2.8 h) was significantly faster than the post-BCID Panel group (17.7 h; P = 0.0041). Conclusions Challenges exist in communicating results to the appropriate personnel on the healthcare team who have the knowledge to act on these data and prescribe targeted therapy against the pathogen(s) identified. In this report, we outline the procedures for telephonic communication and CSP support that were implemented at our health system to distribute RDT data to individuals capable of assessing results, enabling timely optimization of antimicrobial therapy.

Evaluating the impact of rapid antimicrobial susceptibility testing for bloodstream infections: a review of actionability, antibiotic use and patient outcome metrics.

Antimicrobial susceptibility testing (AST) is a core function of the clinical microbiology laboratory and is critical to the management of patients with bloodstream infections (BSIs) to facilitate optimal antibiotic therapy selection. Recent technological advances have resulted in several rapid methods for determining susceptibility direct from positive blood culture that can provide turnaround times in under 8 h, which is considerably shorter than conventional culture-based methods. As diagnostic results do not directly produce a medical intervention, actionability is a primary determinant of the effect these technologies have on antibiotic use and ultimately patient outcomes. Randomized controlled trials and observational studies consistently show that rapid AST significantly reduces time to results and improves antimicrobial therapy for patients with BSI across various methods, patient populations and organisms. To date, the clinical impact of rapid AST has been demonstrated in some observational studies, but randomized controlled trials have not been sufficiently powered to validate many of these findings. This article reviews various metrics that have been described in the literature to measure the impact of rapid AST on actionability, antibiotic exposure and patient outcomes, as well as highlighting how implementation and workflow processes can affect these metrics.

Retrospective evaluation of rapid genotypic ID and phenotypic AST systems on positive blood culture turnaround time and simulated potential impacts on bloodstream infection management

Abstract Background Bloodstream infections are linked to heightened morbidity and mortality rates. The consequences of delayed antibiotic treatment can be detrimental. Effective management of bacteraemia hinges on rapid antimicrobial susceptibility testing. Objectives This retrospective study examined the influence of the VITEK® REVEAL™ Rapid AST system on positive blood culture (PBC) management in a French tertiary hospital. Materials and methods Between November 2021 and March 2022, 79 Gram-negative monomicrobial PBC cases underwent testing with both VITEK®REVEAL™ and VITEK®2 systems. Results The study found that VITEK®REVEAL™ yielded better results than the standard of care, significantly shortening the time to result (7.0 h compared to 9.6 h) as well as the turnaround time (15 h compared to 31.1 h) when applied for all isolates. Conclusions This study implies that the use of VITEK®REVEAL™ enables swift adaptations of antibiotic treatment strategies. By considerably minimizing the turnaround time, healthcare professionals can promptly make necessary adjustments to therapeutic regimens. Notably, these findings underscore the potential of VITEK®REVEAL™ in expediting appropriate antibiotic interventions, even in less ideal conditions. Further studies in varied laboratory contexts are required to validate these encouraging outcomes.

Species distribution, antifungal susceptibility pattern and associated factors of Candida blood stream infections in Sri Lanka from 2018 to 2022

Introduction: Candidemia can be life-threatening in immunocompromised individuals thus, prompt diag-nosis and treatment with antifungal agents is mandatory for successful outcome.Surveillance data on species distribution, antifungal susceptibility and associated factors of candidemia is utmost important to decide on empiric antifungal therapy, to impose infection control measures as well to promote antifungal stewardship in a country.Therefore, this study was aimed at retrospective review of data on candidemia at Mycology Reference Laboratory in Sri Lanka for 5 years duration to identify the species causing candidemia, their antifungal susceptibility pattern and associated factors.Results: A twofold rise in candidemia cases were seen during this 5-year duration compared to previous 7 years (2011-2017). Predominant species causing candidemia was C. tropicalis (35%) followed by C. parapsilosis (33%). C. albicans was the 3rd commonest species causing candidemia in Sri Lanka.There were 3% C. glabrata cases, 2% C. guilliermondii and 1% C. famata and C. krusei cases. Importantly two sequencing confirmed C. auris cases were identified for the first time in Sri Lanka in 2021.Overall good antifungal susceptibility was seen for both fluconazole and amphotericin B and there were only 7%and 1.6% resistance respectively.Long term hospital stay (47%) was commonly seen in this study group followed by use of broad-spectrum antibiotics (24%) and involvement of gastro-intestinal tract (21%).Conclusion: Candida tropicalis is the commonest species causing candidemia in Sri Lanka. Common Candida species had good susceptibility to antifungals. Long term hospital stay was associated with candidemia in majority of patients.

A simple scoring algorithm predicting paravertebral and/or iliopsoas abscess among adults with community-onset bloodstream infections: matters of PVL-producing Staphylococcus aureus

A simple scoring algorithm predicting paravertebral and/or iliopsoas abscess among adults with community-onset bloodstream infections: matters of PVL-producing Staphylococcus aureus

One and Done? An Evaluation of the Clinical Outcomes of Single- and Multi-Dose Dalbavancin Use in the Pediatric Population

Staphylococcus aureus is a leading cause of invasive bacterial infections in the pediatric population. In general, data surrounding the use of newly approved antimicrobials within children are lacking. Dalbavancin is a long-acting lipoglycopeptide that shows promise for off-label use in adults given its unique pharmacokinetics and in vitro potency against common Gram-positive isolates; however, evidence to supports its use in children is limited. We report the use of dalbavancin in three pediatric cases in patients aged 17 months of age, 3 years of age, and 11 years of age. All infections were caused by S. aureus (66.7% methicillin-resistant S. aureus) representing varied disease, including an osteoarticular infection and catheter-related bloodstream infection. Furthermore, all patients had pediatric infectious diseases involvement. Following the utilization of DAL, high clinical success and low rates of adverse effects were observed with high patients’ and parents’ satisfaction. While larger, confirmatory real-world studies are needed, our findings support safe off-label DAL use in select pediatric patients.

Experience of a vascular ultrasound-guided program: from the ICU to the hospital

Abstract Background The use of peripherally inserted central venous catheters (PICCs) has increased worldwide in the last decade. However, PICCs are associated to catheter-related thrombosis (CRT) and central line-associated bloodstream infections (CLABSIs). We describe the characteristics of patients requiring a PICC, estimate the incidence rate, and identify potential risk factors of PICC-related complications. Methods All adult patients requiring a PICC at our institution (Fundación Santa Fe de Bogotá, Bogota, Colombia) from September 2022 to May 2024 were included in the analysis. The database from active PICC monitoring collected demographic and PICC-related information. The incidence rate of CLABSI and CRT, and crude odds ratios (cORs) were estimated. Results Overall, 1936 individuals were included in the study. The median age was 67 years (IQR: 50–78 years), and 51.5% were females. The median duration of PICC lines was 10 days (IQR: 4–17). Seventy-nine patients had catheter-related complications, mostly in the Intensive Care Unit (ICU). The CLABSI and CRT institutional incidence rates per 1000 catheter-days were 2.03 (2.96 in the ICU) and 0.58 (0.61 in the ICU), respectively. Prolonged catheter use (≥ 6 days), PICC insertion in the intensive care unit, and postoperative care after cardiac surgery were identified as potential risk factors for CLABSI, while a catheter insertion into the brachial vein was associated with CRT. Conclusion Daily PICC assessment, particularly in patients with prolonged catheter use, PICC insertion into the brachial vein, or in postoperative care after cardiac surgery may significantly reduce CLABSI and CRT cases. Implementing Vascular Access Teams, venous catheter care bundles, and institutional insertion protocols optimize clinical outcomes.

A 5-year study of bloodstream infections caused by carbapenemase-producing Gram-negative bacilli in southern Spain

Introduction. The aim of this study was to evaluate the microbiological epidemiology of carbapenemase-producing Gram-negative bacilli (CPGNB) isolated from blood during a 5-year period. Methods. A total of 80 isolates from 78 patients were finally included; fifty-five (70.5%) were men and the mean age was 60 years. Detection of carbapenemase production was performed by immunocromatography (IC) and polymerase chain reaction (PCR). Genotyping was carried-out by pulsedfield gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), and characterization of carbapenemase-producing isolates was performed by whole genome sequencing (WGS). Results. The main microorganisms isolated were K. pneumoniae (29.4%), E. cloacae (28.2%), A. baumannii (17.9%) and P. aeruginosa (15.3%). Overall, the most common carbapenemase in Enterobacterales was OXA-48 group (57.7%). The most common carbapenemase in non-fermenting bacilli was OXA-23 (60.8%). The most common ST in K. pneumoniae producing OXA-48 types was ST45 and in E. cloacae ST114, while in E. cloacae producing VIM types was ST78. In OXA-23 types, the most common clone in A. baumannii was ST2, whereas in P. aeruginosa producing IMP types was ST253. Conclusions. There was an increase in cases recorded in the years of highest incidence and severity of the SARS-CoV-2 pandemic, with a significant number of cases in patients admitted to the ICU. All bacteremias caused by A. baumannii were caused by the same clone, and 12 of the 14 cases caused by A. baumannii were part of outbreaks in the ICU.

Antimicrobial resistance of Serratia marcescens causing blood stream infections in a large University Hospital in Bulgaria, an 8-year analysis (2016-2023).

The aim of this study is to evaluate the antimicrobial susceptibility of invasive isolates of Serratia marcescens, associated with blood stream infections (BSIs) in patients hospitalized in Varna University Hospital, Bulgaria, as well as to identify the genetic mechanisms responsible for 3rd generation cephalosporin and carbapenem-resistance among these isolates. A total of 45 consecutive S. marcescens isolates, obtained from blood cultures of 45 patients with BSIs, hospitalized during an 8-year period (2016-2023) were included. Species identification and antimicrobial susceptibility testing were done by Phoenix (BD, USA) and Vitek 2 (BioMerieux, France) systems and the results were interpreted according to EUCAST guidelines. The genetic mechanisms of beta-lactam resistance were studied by PCR. During the study period, a total of 45 patients were diagnosed with S. marcescens-associated BSIs. All infections were defined as nosocomial, predominantly intensive care unit-acquired (42.2%) and 28.8% were central venous catheter-associated. The following antimicrobial resistance rates were found: ceftriaxone,piperacillin/tazobactam, 57.8%; ceftazidime, 55.6%; cefepime, trimethoprime/sulfamethoxazole, 53.3%; gentamicin, 48.8%; ciprofloxacin, 44.5%; amikacin, 15.6%; carbapenems, 2.2%. TheblaCTX-M was identified in 88.9% of the tested 3rd generation cephalosporin resistant isolates. Among these, 50% were also blaTEM positive. The single carbapenem-resistant isolate harboured blaKPC, blaCTX-M1/9, blaCMY-2 and blaTEM. This study demonstrates S. marcescens as a problematic nosocomial pathogen and we report a KPC-producing S. marcescens clinical isolate from a BSI in Bulgaria.

ST105 Lineage of MRSA: An Emerging Implication for Bloodstream Infection in the American and European Continents.

Sequence-type 5 (ST5) of methicillin-resistant Staphylococcus aureus (MRSA), harboring the staphylococcal chromosomal cassette mec type IV (SCCmecIV), was first detected in Portugal. It emerged as a significant cause of healthcare-associated (HA) infection in pediatric units and was hence named the pediatric clone. Another ST5 lineage, which carries SCCmecII, also prevailed in the USA and Japan for multiple years. More recently, another MRSA lineage, ST105-SCCmecII, part of the evolution of clonal complex 5 (CC5) MRSA, has emerged as the cause of hospital-acquired bloodstream infection outbreaks in countries including Portugal, the USA, and Brazil. This article reviews studies on the epidemiology and evolution of these newly emerging pathogens. To this end, a search of PUBMED from inception to 2024 was performed to find articles reporting the occurrence of ST105 MRSA in epidemiologic studies. A second search was performed to find studies on MRSA, CC5, ST5, and SCCmecII. A search of PUBMED from 1999 to 2024 was also performed to identify studies on the genomics and evolution of ST5, CC5, and ST105 MRSA. Further studies were identified by analyzing the references of the previously selected articles from PUBMED. Most articles on ST105 MRSA were included in this review. Only articles written in English were included. Furthermore, only studies that used a reliable genotyping method (e.g., whole genome sequencing, or MLST) to classify the CC5 lineages were selected. The quality and selection of articles were based on the consensus assessment of the three authors in independent evaluations. In conclusion, ST105-SCCmecII is an emerging MRSA in several countries, being the second/third most important CC5 lineage, with a relatively high frequency in bloodstream infections. Of concern is the increased mortality from BSI in patients older than 15 years and the higher prevalence of ST105-SCCmecII in the blood of patients older than 60 years reported in some studies.

The presence of genes encoding carbapenem-hydrolyzing oxacillinase and lack of carbapenem resistance in non-baumannii Acinetobacter misidentified as Acinetobacter baumannii causing bloodstream infections in a tertiary hospital over a 3-year period

ObjectiveThis study aims to analyze the genomic and clinical characteristics of Non-baumannii Acinetobacter strains misidentified as A. baumannii, causing bloodstream infections (BSIs) in our hospital. Materials and methodsWhole genome sequencing was performed and average nucleotide identity (ANI) was analyzed. Susceptibility testing was conducted using micro-broth methods. The distribution of antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) was examined using online software tools. The prevalence of virulence factors (VFs) was investigated through nucleotide coding sequence comparisons. Genetic structures of blaOXA genes were analyzed by Gcluster software. Clinical information was collected from electronic medical records for patient characterization. ResultsANI analysis identified five strains as Acinetobacter pittii, with the remaining four identified as A. geminorum, A. nosocomialis, A. soli and A. bereziniae. The GC content of all isolates was less than 38.9 % except for A. soli 16,294. All Non-baumannii Acinetobacter strains were relatively susceptible to antibiotics, except for one A. pittii isolate. Nine blaOXA variants were identified in seven isolates, with two isolates co-carrying 2 different types of blaOXA. Twenty-four insertion sequences (ISs) were identified, with ISAba and IS17 being the primary ISs. Five A. pittii isolates shared the same genetic structures around blaOXA. Genes related to adherence, immune modulation, and nutritional/metabolic factors were the most frequent. Few VFs were detected in A. soli 16,294 and A.bereziniae 14,325. ConclusionsThe presence of carbapenem hydrolyzing oxacillinase encoding genes did not confer carbapenem resistance, possibly due to the lack of ISs in the blaOXA flanking sequences. Different blaOXA variants within distinct strains shared the same genetic structures, suggesting potential for multidrug resistance development, which warrants our attention.