Secular trends in nosocomial bloodstream infections: antibiotic-resistant bacteria increase the total burden of infection

Impact of multidrug resistance on the virulence and fitness of Pseudomonas aeruginosa: a microbiological and clinical perspective

Pseudomonas aeruginosa is one of the most common nosocomial pathogens and part of the top emergent species associated with antimicrobial resistance that has become one of the greatest threat to public health in the twenty-first century. This bacterium is provided with a wide set of virulence factors that contribute to pathogenesis in acute and chronic infections. This review aims to summarize the impact of multidrug resistance on the virulence and fitness of P. aeruginosa. Although it is generally assumed that acquisition of resistant determinants is associated with a fitness cost, several studies support that resistance mutations may not be associated with a decrease in virulence and/or that certain compensatory mutations may allow multidrug resistance strains to recover their initial fitness. We discuss the interplay between resistance profiles and virulence from a microbiological perspective but also the clinical consequences in outcomes and the economic impact.

ProQ binding to small RNA RyfA promotes virulence and biofilm formation in avian pathogenic Escherichia coli

Avian pathogenic Escherichia coli (APEC) is a notable subpathotype of the nonhuman extraintestinal pathogenic E. coli (ExPEC). Recognized as an extraintestinal foodborne pathogen, the zoonotic potential of APEC/ExPEC allows for cross-host transmission via APEC-contaminated poultry meat and eggs. ProQ, an RNA binding protein, is evolutionarily conserved in E. coli. However, its regulatory roles in the biofilm formation and virulence of APEC/ExPEC have not been explored. In this study, proQ deletion in the APEC strain FY26 significantly compromised its biofilm-forming ability. Furthermore, animal tests and cellular infection experiments showed that ProQ depletion significantly attenuated APEC virulence, thereby diminishing its capacity for bloodstream infection and effective adherence to and persistence within host cells. Transcriptome analysis revealed a decrease in the transcription level of the small RNA (sRNA) RyfA in the mutant FY26ΔproQ, suggesting a direct interaction between the sRNA RyfA and ProQ. This interaction might indicate that sRNA RyfA is a novel ProQ-associated sRNA. Moreover, the direct binding of ProQ to the sRNA RyfA was crucial for APEC biofilm formation, pathogenicity, adhesion, and intracellular survival. In conclusion, our findings provide detailed insight into the interaction between ProQ and sRNA RyfA and deepen our understanding of the regulatory elements that dictate APEC virulence and biofilm development. Such insights are instrumental in developing strategies to counteract APEC colonization within hosts and impede APEC biofilm establishment on food surfaces.

Pseudomonas aeruginosa quorum-sensing molecule N-(3-oxododecanoyl)-L-homoserine lactone mediates Ca+2 dysregulation, mitochondrial dysfunction, and apoptosis in human peripheral blood lymphocytes

N-(3-oxododecanoyl)-l-homoserine lactone is a Pseudomonas aeruginosa secreted quorum-sensing molecule that mediates the secretion of virulence factors, biofilm formation and plays a pivotal role in proliferation and persistence in the host. Apart from regulating quorum-sensing, the autoinducer signal molecule N-(3-oxododecanoyl)-l-homoserine lactone (3O-C12-HSL or C12) of a LasI-LasR circuit exhibits immunomodulatory effects and induces apoptosis in various host cells. However, the precise pathophysiological impact of C12 on human peripheral blood lymphocytes and its involvement in mitochondrial dysfunction remained largely elusive. In this study, the results suggest that C12 (100 μM) induces upregulation of cytosolic and mitochondrial Ca+2 levels and triggers mitochondrial dysfunction through the generation of mitochondrial ROS (mROS), disruption of mitochondrial transmembrane potential (ΔΨm), and opening of the mitochondrial permeability transition pore (mPTP). Additionally, it was observed that C12 induces phosphatidylserine (PS) exposure and promotes apoptosis in human peripheral blood lymphocytes. However, apoptosis plays a critical role in the homeostasis and development of lymphocytes, whereas enhanced apoptosis can cause immunodeficiency through cell loss. These findings suggest that C12 exerts a detrimental effect on lymphocytes by mediating mitochondrial dysfunction and enhancing apoptosis, which might further impair the effective mounting of immune responses during Pseudomonas aeruginosa-associated infections.

Bridging Molecular and Clinical Sciences to Achieve the Best Treatment of Enterococcus faecalis Endocarditis

Enterococcus faecalis (E. faecalis) is a commensal bacterium that causes various infections in surgical sites, the urinary tract, and blood. The bacterium is becoming a significant concern because it tends to affect the elderly population, which has a high prevalence of undiagnosed degenerative valvular disease and is often subjected to invasive procedures and implanted medical devices. The bacterium's actions are influenced by specific characteristics like pili activity and biofilm formation. This resistance significantly impedes the effectiveness of numerous antibiotic therapies, particularly in cases of endocarditis. While current guidelines recommend antimicrobial therapy, the emergence of resistant strains has introduced complexity in managing these patients, especially with the increasing use of transcatheter therapies for those who are not suitable for surgery. Presentations of the condition are often varied and associated with generalised symptoms, which may pose a diagnostic challenge. We share our encounter with a case study that concerns an octogenarian who had a TAVI valve and developed endocarditis. We also conducted a literature review to identify the essential treatment algorithms for such cases.

A Literature Review on the Use of Aortic Allografts in Modern Cardiac Surgery for the Treatment of Infective Endocarditis: Is There Clear Evidence or Is It Merely a Perception?

Infective valve endocarditis is caused by different pathogens and 60% of those involve the aortic valve with valve failure. Although S. aureus is recognized as the most frequently isolated causative bacterium associated with IE in high-income countries, Gram-positive cocci nevertheless play a crucial role in promoting infection in relation to their adhesive matrix molecules. The presence of pili on the surface of Gram-positive bacteria such as in different strains of Enterococcus faecalis and Streptococcus spp., grants these causative pathogens a great offensive capacity due to the formation of biofilms and resistance to antibiotics. The indications and timing of surgery in endocarditis are debated as well as the choice of the ideal valve substitute to replace the diseased valve(s) when repair is not possible. We reviewed the literature and elaborated a systematic approach to endocarditis management based on clinical, microbiological, and anatomopathological variables known to affect postoperative outcomes with the aim to stratify the patients and orient decision making. From this review emerges significant findings on the risk of infection in the allograft used in patients with endocarditis and no endocarditis etiology suggesting that the use of allografts has proved safety and effectiveness in patients with both pathologies.

Enterococci Isolated from One-Day-Old Chickens and Their Phenotypic Susceptibility to Antimicrobials in the Czech Republic

Our study describes the prevalence and spectrum of enterococci isolated from one-day-old chickens in the Czech Republic, their level of antimicrobial resistance, and the occurrence of multiresistance. Over a 24-month period from 1 August 2021 to 31 July 2023, a total of 464 mixed samples of one-day-old chicken organs were examined during routine inspections at 12 randomly selected poultry farms in the Czech Republic. The samples were processed via cultivation methods and suspected strains were confirmed using the MALDI-TOF Mass Spectrometry method. Antimicrobial susceptibility was determined using the MIC method for eight antimicrobials. A total of 128 isolates (prevalence of 27.6%) representing 4 species of enterococci were isolated, including Enterococcus faecalis, Enterococcus faecium, Enterococcus gallinarum, and Enterococcus hirae, with prevalence rates of 23.3%, 1.5%, 2.2%, and 0.6%, respectively. Susceptibility tests showed a high percentage of susceptible strains among E. faecalis, E. faecium, and E. gallinarum for penicillin-based antibiotics, sulfamethoxazole with trimethoprim, and florfenicol (80-100% susceptible strains). E. hirae was an exception, displaying complete resistance to enrofloxacin (0% susceptible strains) and a high degree of resistance to other tested antimicrobials (33.3% susceptible strains). Among the isolated strains, a total of 16 isolates (12.5%) showed resistance to 3 or more antimicrobials. Complete resistance to all eight antimicrobials simultaneously was observed in four isolates (3.1%). This research shows the possible sources of pathogenic enterococci and their virulence and resistance genes. The findings hold relevance for both veterinary and human medicine, contributing to a better understanding of enterococcal circulation in the human ecosystem and food chain, as well as the development of their resistance and multiresistance.

A prospective cluster trial to increase antibiotic prescription quality in seven non-ICU wards

Aim

To evaluate general shortcomings and faculty-specific pitfalls as well as to improve antibiotic prescription quality (ABQ) in non-ICU wards, we performed a prospective cluster trial.

Methods

An infectious-disease (ID) consulting service performed a prospective investigation consisting of three 12-week phases with point prevalence evaluation conducted once per week (=36 evaluations in total) at seven non-ICU wards, followed by assessment of sustainability (weeks 37-48). Baseline evaluation (phase 1) defined multifaceted interventions by identifying the main shortcomings. Then, to distinguish intervention from time effects, the interventions were performed in four wards, and the 3 remaining wards served as controls; after assessing effects (phase 2), the same interventions were performed in the remaining wards to test the generalizability of the interventions (phase 3). The prolonged responses after all interventions were then analyzed in phase 4. ABQ was evaluated by at least two ID specialists who assessed the indication for therapy, the adherence to the hospital guidelines for empirical therapy, and the overall antibiotic prescription quality.

Results

In phase 1, 406 of 659 (62%) patients cases were adequately treated with antibiotics; the main reason for inappropriate prescription was the lack of an indication (107/253; 42%). The antibiotic prescription quality (ABQ) significantly increased, reaching 86% in all wards after the focused interventions (502/584; nDf=3, ddf=1,697, F=6.9, p=0.0001). In phase 2 the effect was only seen in wards that already participated in interventions (248/347; 71%). No improvement was seen in wards that received interventions only after phase 2 (189/295; 64%). A given indication significantly increased from about 80% to more than 90% (p<.0001). No carryover effects were observed.

Discussion

ABQ can be improved significantly by intervention bundles with apparent sustainable effects.

Infective endocarditis after transcatheter pulmonary valve implantation in patients with congenital heart disease: Distinctive features

The introduction of transcatheter pulmonary valve implantation (TPVI) has greatly benefited the management of right ventricular outflow tract dysfunction. Infective endocarditis (IE) is a feared complication of TPVI that affects valve durability and patient outcomes. Current recommendations provide only limited guidance on the management of IE after TPVI (TPVI-IE). This article, by a group of experts in congenital heart disease in children and adults, interventional cardiology, infectious diseases including IE, and microbiology, provides a comprehensive review of the current evidence on TPVI-IE, including its incidence, risk factors, causative organisms, diagnosis, and treatment. The incidence of TPVI-IE varies from 13-91/1000 person-years for Melody valves to 8-17/1000 person-years for SAPIEN valves. Risk factors include history of IE, DiGeorge syndrome, immunosuppression, male sex, high residual transpulmonary gradient and portal of bacteria entry. Staphylococci and streptococci are the most common culprits, whereas Staphylococcus aureus is associated with the most severe disease. In addition to the modified Duke criteria, a high residual gradient warrants a strong suspicion. Imaging studies are helpful for the diagnosis. Intravenous antibiotics guided by blood culture results are the mainstay of treatment. Invasive re-intervention may be required. TPVI-IE in patients with congenital heart disease exhibits several distinctive features. Whether specific valve types are associated with a higher risk of TPVI-IE requires further investigation. Patient and parent education regarding IE prevention may have a role to play and should be offered to all patients.

Pseudomonas quinolone signal induces organelle stress and dysregulates inflammation in human macrophages

Pseudomonas quinolone signal (PQS) is a quorum-sensing molecule associated with Pseudomonas aeruginosa that regulates quorum sensing, extracellular vesicle biogenesis, iron acquisition, and the secretion of virulence factors. PQS has been shown to have immunomodulatory effects on the host. It induces oxidative stress, modulates cytokine levels, and activates regulated cell death in the host. In this study, we investigated the effects of PQS (10 μM) on host organelle dynamics and dysfunction in human macrophages at the interphase of endoplasmic reticulum (ER), mitochondria, and lysosome. This study showed that PQS increases cytosolic Ca⁺² levels and elevates ER stress, as evidenced by increased expression of BiP and activation of the PERK-CHOP axis of unfolded protein response (UPR). Moreover, PQS also negatively affects mitochondria by disrupting mitochondrial membrane potential and increasing mitochondrial ROS generation (mROS). Additionally, PQS stimulation decreased the number of acridine orange-positive lysosomes, indicating lysosomal destabilization. Furthermore, PQS-induced lysosomal destabilization also induces overexpression of the lysosomal stress-responsive gene TFEB. Besides organelle dysfunction, PQS dysregulates inflammation-related genes by upregulating NLRC4, TMS1, and Caspase 1 while downregulating NLRP3 and IL-1β. Also, PQS increases gene expression of pro-inflammatory cytokines (IL-6, TNF-α, and IFN-γ). In conclusion, our findings suggest that PQS negatively affects human macrophages by interfering with organelle function and dysregulating inflammatory response. Consequently, this study provides crucial insight into PQS-driven macrophage dysfunction and may contribute to a better understanding of Pseudomonas aeruginosa-associated infections.

Prevalence of Staphylococcus spp. from human specimens submitted to diagnostic laboratories in South Africa, 2012-2017

Background

Although staphylococci are commensals of the skin and mucosa of humans and animals, they are also opportunistic pathogens. Some coagulase-negative Staphylococcus spp. (CoNS), such as S. haemolyticus and S. epidermidis, are reported to be zoonotic.

Objectives

The prevalence of coagulase positive (CoPS), CoNS and coagulase-variable Staphylococcus spp. isolated from human clinical cases in South Africa was investigated.

Method

Retrospective records of 404 217 diagnostic laboratory submissions from 2012 to 2017 were examined and analysed in terms of time, place and person.

Results

Of the 32 different species identified, CoPS were the most frequently isolated (74.7%), followed by CoNS (18.9%). Just over half (51.2%) of the Staphylococcus isolates were from males, while females contributed 44.8%. Patients aged 0-4 years contributed the most (21.5%) isolates, with the highest number coming from KwaZulu-Natal (32.8%). Urinary specimens accounted for 29.8% of the isolates reported. There was no variation in the number of Staphylococcus isolates reported in the autumn (25.2%), winter (25.2%), spring (25.1%) and summer (24.5%) seasons.

Conclusion

This study demonstrated the diversity of Staphylococcus spp. isolated from humans and the magnitude of infection, with the most predominant species being S. aureus and S. epidermidis.

Contribution

Although most isolates were CoPS, the isolation of CoNS seen in this study suggests a need to improve infection control measures in a South African context. More research is needed to investigate the determinants of the observed variations in the study.

Endocarditis: Who Is Particularly at Risk and Why? Ten Years Analysis of Risk Factors for In-hospital Mortality in Infective Endocarditis

BACKGROUND

Endocarditis is continuously increasing. Evidence exist that the prognosis is adversely affected by the extent of the disease. We looked at risk factors influencing in-hospital mortality (HM).

PATIENTS AND METHODS

Between 2010 and 2019, 484 patients, 338 males (69.8%) with mean age of 66.1 years were operated on because of proven endocarditis. In a retrospective study, a risk factor analysis was performed.

RESULTS

Overall HM was 30.17%. Significant influencing factors (odds ratios [ORs] or p-value) for HM were: age (p = 0.004), logistic EuroSCORE (p< 0.001), gender (OR = 1.64), dialysis (OR = 2.64), hepatic insufficiency (OR = 2.17), reoperation (OR = 1.77), previously implanted valve (OR = 1.97), periannular abscess (OR = 9.26), sepsis on admission (OR = 12.88), and number of involved valves (OR = 1.96). Development of a sepsis and HM was significantly lower if Streptococcus mitis was the main pathogen in contrast to other bacteria (p< 0.001). Staphylococcus aureus was significantly more often found in patients with a previously implanted prosthesis (p = 0.03) and in recurrent endocarditis (p = 0.02), while it significantly more often showed peripheral septic emboli than the other pathogens (p< 0.001).

CONCLUSION

Endocarditis remains life-threatening. Severe comorbidities adversely affected early outcome, particularly, in presence of periannular abscesses. Patients with suspected endocarditis should be admitted to a specialized heart center as early as possible. Streptococcus mitis appears to be less virulent than S. aureus. Further studies are required to verify these findings.

Outcomes of octogenarians and nonagenarians with Pseudomonas aeruginosa bacteremia: a multicenter retrospective study

BACKGROUND

P. aeruginosa bacteremia is a common and severe infection carrying high mortality in older adults. We aimed to evaluate outcomes of P. aeruginosa bacteremia among old adults (≥ 80 years).

METHODS

We included the 464/2394 (19%) older adults from a retrospective multinational (9 countries, 25 centers) cohort study of individuals hospitalized with P. aeruginosa bacteremia. Bivariate and multivariable logistic regression models were used to evaluate risk factors for 30-day mortality among older adults.

RESULTS

Among 464 adults aged ≥ 80 years, the mean age was 84.61 (SD 3.98) years, and 274 (59%) were men. Compared to younger patients, ≥ 80 years adults had lower Charlson score; were less likely to have nosocomial acquisition; and more likely to have urinary source. Thirty-day mortality was 30%, versus 27% among patients 65-79 years (n = 894) and 25% among patients < 65 years (n = 1036). Multivariate analysis for predictors of mortality among patients ≥ 80 years, demonstrated higher SOFA score (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.23-1.51, p < 0.001), corticosteroid therapy (OR 3.15, 95% CI: 1.24-8.01, p = 0.016) and hospital acquired P. aeruginosa bacteremia (OR 2.30, 95% CI: 1.33-3.98, p = 0.003) as predictors. Appropriate empirical therapy within 24 h, type of definitive anti-pseudomonal drug, and type of regimen (monotherapy or combination) were not associated with 30-day mortality.

CONCLUSIONS

In older adults with P. aeruginosa bacteremia, background conditions, place of acquisition, and disease severity are associated with mortality, rather than the antimicrobial regimen. In this regard, preventive efforts and early diagnosis before organ failure develops might be beneficial for improving outcomes.

Novel dalbavancin-PLLA implant coating prevents hematogenous Staphylococcus aureus infection in a minimally invasive mouse tail vein model

Infective/bacterial endocarditis is a rare but life-threatening disease with a hospital mortality rate of 22.7% and a 1-year mortality rate of 40%. Therefore, continued research efforts to develop efficient anti-infective implant materials are of the utmost importance. Equally important is the development of test systems that allow the performance of new materials to be comprehensively evaluated. In this study, a novel antibacterial coating based on dalbavancin was tested in comparison to rifampicin/minocycline, and the suitability of a recently developed mouse tail vein model for testing the implant coatings was validated. Small polymeric stent grafts coated with a poly-L-lactic acid (PLLA) layer and incorporated antibiotics were colonized with Staphylococcus (S.) aureus before implantation into the tail vein of mice. The main assessment criteria were the hematogenous spread of the bacteria and the local tissue reaction to the contaminated implant. For this purpose, colony-forming units (CFU) in the blood, spleen and kidneys were determined. Tail cross sections were prepared for histological analysis, and plasma cytokine levels and expression values of inflammation-associated genes were examined. Both antibiotic coatings performed excellently, preventing the onset of infection. The present study expands the range of available methods for testing the anti-infectivity of cardiovascular implants, and the spectrum of agents for effective surface coating.

Prompt and Appropriate Antimicrobial Therapy Improves Outcomes of NDM-Producing and KPC-Producing Klebsiella pneumoniae Bloodstream Infections in Patients Hospitalized for COVID-19: A Comparative Retrospective Case-Series

Secondary bloodstream infections (BSIs) caused by KPC- and NDM-producing Klebsiella pneumoniae (K.p.) during the course of COVID-19 infections lead to significant mortality. Herein, a comparative retrospective case series of KPC- or NDM-K.p. BSIs occurring in COVID-19 subjects treated with Ceftazidime/Avibactam (CAZ/AVI) for KPC-K.p., or CAZ/AVI+ Aztreonam (ATM) for NDM-K.p is reported. All patients hospitalized for COVID-19 in two Italian hospitals with a BSI between March and September 2021 were included. The main outcome was 14-day mortality. Overall, 44 patients were included: 23 with KPC-K.p. and 21 with NDM-K.p. BSIs. The median (q1–q3) age was 67 (57–75) years, and 32 (72%) were males. The two groups were similar in terms of baseline comorbidity, or severity of COVID-19. Notably, 14-day mortality of KPC-K.p. BSIs and NDM-K.p. BSIs (26% vs. 38%, p = 0.521) and 28-day mortality (35% vs. 48%, p = 0.541) were similar. A Cox regression model of delayed initiation of an appropriate antibiotic therapy after the onset of symptoms independently predicted mortality: initiation between 24 and 72 h (aHR = 12.03; 95% CI = 1.10–130, p = 0.041); and initiation after 72h (aHR = 36.9, 95% CI = 3.22–424, p = 0.004). Moreover, a trend towards an increased risk of mortality was observed for polymicrobial infections (aHR = 3.73, 95% CI = 0.87–15.8, p = 0.074), while a protective effect was observed for a beta-lactam loading dose at the start of treatment (aHR = 0.16, 95% CI = 0.02–1.10, p = 0.064). The high mortality of KPC and NDM-K.p. BSIs in COVID-19 patients may be reduced by an early and appropriate antibiotic therapy. Further efforts should be made to develop antimicrobial stewardship and infection control programs in COVID-19 wards.

Methicillin-resistant staphylococcus aureus nosocomial infection has a distinct epidemiological position and acts as a marker for overall hospital-acquired infection trends

An ongoing healthcare debate is whether controlling hospital-acquired infection (HAI) from methicillin-resistant Staphylococcus aureus (MRSA) will result in lowering the global HAI rate, or if MRSA will simply be replaced by another pathogen and there will be no change in overall disease burden. With surges in drug-resistant hospital-acquired pathogens during the COVID-19 pandemic, this remains an important issue. Using a dataset of more than 1 million patients in 51 acute care facilities across the USA, and with the aid of a threshold model that models the nonlinearity in outbreaks of diseases, we show that MRSA is additive to the total burden of HAI, with a distinct 'epidemiological position', and does not simply replace other microbes causing HAI. Critically, as MRSA is reduced it is not replaced by another pathogen(s) but rather lowers the overall HAI burden. The analysis also shows that control of MRSA is a benchmark for how well all non-S. aureus nosocomial infections in the same hospital are prevented. Our results are highly relevant to healthcare epidemiologists and policy makers when assessing the impact of MRSA on hospitalized patients. These findings further stress the major importance of MRSA as a unique cause of nosocomial infections, as well as its pivotal role as a biomarker in demonstrating the measured efficacy (or lack thereof) of an organization's Infection Control program.

Infectious Disease Consults of Pseudomonas aeruginosa Bloodstream Infection and Impact on Health Outcomes

Background

Infectious diseases (ID) consultation improves health outcomes for certain infections but has not been well described for Pseudomonas aeruginosa (PA) blood stream infection (BSI). Therefore, the goal of this study was to examine ID consultation of inpatients with PA BSI and factors impacting outcomes.

Methods

This was a retrospective cohort study from January 1, 2012 - December 31, 2018 of adult hospitalized Veterans with PA BSI and antibiotic treatment 2 days before through 5 days after the culture date. Multidrug resistant (MDR) cultures were defined as resistance to at least 1 agent in ≥ 3 antimicrobial categories tested. Multivariable logistic regression models were fit to assess the impact of ID consults and adequate treatment on mortality.

Results

3,256 patients had PA BSI, of which 367 (11.3%) were multi-drug resistant (MDR). Most were male (97.5%), over 65 years old (71.2%), and white (70.9%). Nearly one-fourth (n = 784, 23.3%) died during hospitalization and 870 (25.8%) died within 30-days of their culture. Adjusted models showed ID consultation was associated with decreased in-hospital (odds ratio (OR) = 0.47, 95% CI: 0.39-0.56) and 30-day mortality (OR = 0.51, 95% CI: 0.42-0.62).

Conclusions

Consultation with ID physicians improves clinical outcomes such as in-hospital and 30-day mortality for patients with PA BSI. ID consultation provides value and should be considered for patients with PA BSI.

Infective Endocarditis in High-Income Countries

Infective endocarditis remains an illness that carries a significant burden to healthcare resources. In recent times, there has been a shift from Streptococcus sp. to Staphylococcus sp. as the primary organism of interest. This has significant consequences, given the virulence of Staphylococcus and its propensity to form a biofilm, rendering non-surgical therapy ineffective. In addition, antibiotic resistance has affected treatment of this organism. The cohorts at most risk for Staphylococcal endocarditis are elderly patients with multiple comorbidities. The innovation of transcatheter technologies alongside other cardiac interventions such as implantable devices has contributed to the increased risk attributable to this cohort. We examined the pathophysiology of infective endocarditis carefully. Inter alia, the determinants of Staphylococcus aureus virulence, interaction with host immunity, as well as the discovery and emergence of a potential vaccine, were investigated. Furthermore, the potential role of prophylactic antibiotics during dental procedures was also evaluated. As rates of transcatheter device implantation increase, endocarditis is expected to increase, especially in this high-risk group. A high level of suspicion is needed alongside early initiation of therapy and referral to the heart team to improve outcomes.

Identification of Antibiotic Resistance Proteins via MiCId's Augmented Workflow. A Mass Spectrometry-Based Proteomics Approach

Fast and accurate identifications of pathogenic bacteria along with their associated antibiotic resistance proteins are of paramount importance for patient treatments and public health. To meet this goal from the mass spectrometry aspect, we have augmented the previously published Microorganism Classification and Identification (MiCId) workflow for this capability. To evaluate the performance of this augmented workflow, we have used MS/MS datafiles from samples of 10 antibiotic resistance bacterial strains belonging to three different species: Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The evaluation shows that MiCId's workflow has a sensitivity value around 85% (with a lower bound at about 72%) and a precision greater than 95% in identifying antibiotic resistance proteins. In addition to having high sensitivity and precision, MiCId's workflow is fast and portable, making it a valuable tool for rapid identifications of bacteria as well as detection of their antibiotic resistance proteins. It performs microorganismal identifications, protein identifications, sample biomass estimates, and antibiotic resistance protein identifications in 6-17 min per MS/MS sample using computing resources that are available in most desktop and laptop computers. We have also demonstrated other use of MiCId's workflow. Using MS/MS data sets from samples of two bacterial clonal isolates, one being antibiotic-sensitive while the other being multidrug-resistant, we applied MiCId's workflow to investigate possible mechanisms of antibiotic resistance in these pathogenic bacteria; the results showed that MiCId's conclusions agree with the published study. The new version of MiCId (v.07.01.2021) is freely available for download at https://www.ncbi.nlm.nih.gov/CBBresearch/Yu/downloads.html.

Attributable mortality of vancomycin resistance in ampicillin-resistant Enterococcus faecium bacteremia in Denmark and the Netherlands: A matched cohort study

OBJECTIVE

To study whether replacement of nosocomial ampicillin-resistant Enterococcus faecium (ARE) clones by vancomycin-resistant E. faecium (VRE), belonging to the same genetic lineages, increases mortality in patients with E. faecium bacteremia, and to evaluate whether any such increase is mediated by a delay in appropriate antibiotic therapy.

DESIGN

Retrospective, matched-cohort study.

SETTING

The study included 20 Dutch and Danish hospitals from 2009 to 2014.

PATIENTS

Within the study period, 63 patients with VRE bacteremia (36 Dutch and 27 Danish) were identified and subsequently matched to 234 patients with ARE bacteremia (130 Dutch and 104 Danish) for hospital, ward, length of hospital stay prior to bacteremia, and age. For all patients, 30-day mortality after bacteremia onset was assessed.

METHODS

The risk ratio (RR) reflecting the impact of vancomycin resistance on 30-day mortality was estimated using Cox regression with further analytic control for confounding factors.

RESULTS

The 30-day mortality rates were 27% and 38% for ARE in the Netherlands and Denmark, respectively, and the 30-day mortality rates were 33% and 48% for VRE in these respective countries. The adjusted RR for 30-day mortality for VRE was 1.54 (95% confidence interval, 1.06-2.25). Although appropriate antibiotic therapy was initiated later for VRE than for ARE bacteremia, further analysis did not reveal mediation of the increased mortality risk.

CONCLUSIONS

Compared to ARE bacteremia, VRE bacteremia was associated with higher 30-day mortality. One explanation for this association would be increased virulence of VRE, although both phenotypes belong to the same well-characterized core genomic lineage. Alternatively, it may be the result of unmeasured confounding.

The Global, Regional, and National Burden and Trends of Infective Endocarditis From 1990 to 2019: Results From the Global Burden of Disease Study 2019

Introduction

Infective endocarditis (IE) presents with increasing incidence and mortality in some regions and countries, as well as serious socioeconomic burden. The current study aims to compare and interpret the IE burden and temporal trends globally and in different regions from 1990 to 2019.

Methods

Data on the incidence, deaths and disability-adjusted life years (DALYs) caused by IE were extracted and analyzed from the Global Burden of Disease Study 2019. Estimated annual percentage changes (EAPC) were adopted to quantify the change trends of age-standardized rates (ASRs). Besides, potential contributors of serious IE burden were also evaluated including age, gender, social-demographic index (SDI), and age-standardized incident rate (ASIR) in 1990.

Results

Globally, the number of IE cases and deaths has increased sharply during the past 30 years from 478,000 in 1990 to 1,090,530 in 2019 and from 28,750 in 1990 to 66,320 in 2019, and both presented an upward temporal trend annually (EAPC:1.2 for incidence and 0.71 for death). However, the EAPC of age-standardized DALYs demonstrated a negative temporal trend despite increasing DALYs from 1,118,120 in 1990 to 1,723,590 in 2019. Moreover, older patients and men were more severely affected. Meanwhile, different SDI regions had different disease burdens, and correlation analyses indicated that SDI presented a positive association with ASIR (R = 0.58, P < 0.0001), no association with age-standardized death rate (R = −0.06, P = 0.10), and a negative association with age-standardized DALYs (R = −0.40, P < 0.0001). In addition, the incidence of IE increased in most countries during the past 30 years (190 out of 204 countries). However, the change trends of deaths and DALYs were heterogeneous across regions and countries. Finally, we discovered positive associations of the EAPC of ASRs with the SDI in 2019 among 204 countries and territories but few associations with the ASIR in 1990.

Conclusion

Generally, the global burden of IE is increasing, and there is substantial heterogeneity in different genders, ages and regions, which may help policy-makers and medical staff respond to IE and formulate cost-effective interventional measures.

Does plasmid-based beta-lactam resistance increase E. coli infections: Modelling addition and replacement mechanisms

Infections caused by antibiotic-resistant bacteria have become more prevalent during past decades. Yet, it is unknown whether such infections occur in addition to infections with antibiotic-susceptible bacteria, thereby increasing the incidence of infections, or whether they replace such infections, leaving the total incidence unaffected. Observational longitudinal studies cannot separate both mechanisms. Using plasmid-based beta-lactam resistant E. coli as example we applied mathematical modelling to investigate whether seven biological mechanisms would lead to replacement or addition of infections. We use a mathematical neutral null model of individuals colonized with susceptible and/or resistant E. coli, with two mechanisms implying a fitness cost, i.e., increased clearance and decreased growth of resistant strains, and five mechanisms benefitting resistance, i.e., 1) increased virulence, 2) increased transmission, 3) decreased clearance of resistant strains, 4) increased rate of horizontal plasmid transfer, and 5) increased clearance of susceptible E. coli due to antibiotics. Each mechanism is modelled separately to estimate addition to or replacement of antibiotic-susceptible infections. Fitness costs cause resistant strains to die out if other strain characteristics are maintained equal. Under the assumptions tested, increased virulence is the only mechanism that increases the total number of infections. Other benefits of resistance lead to replacement of susceptible infections without changing the total number of infections. As there is no biological evidence that plasmid-based beta-lactam resistance increases virulence, these findings suggest that the burden of disease is determined by attributable effects of resistance rather than by an increase in the number of infections.

Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks

Backyard birds are small flocks that are more common in developing countries. They are used for poultry meat and egg production. However, they are also implicated in the maintenance and transmission of several zoonotic diseases, including multidrug-resistant bacteria. Enterococci are one of the most common zoonotic bacteria. They colonize numerous body sites and cause a wide range of serious nosocomial infections in humans. Therefore, the objective of the present study was to investigate the diversity in Enterococcus spp. in healthy birds and to determine the occurrence of multidrug resistance (MDR), multi-locus sequence types, and virulence genes and biofilm formation. From March 2019 to December 2020, cloacal swabs were collected from 15 healthy backyard broiler flocks. A total of 90 enterococci strains were recovered and classified according to the 16S rRNA sequence into Enterococcus faecalis (50%); Enterococcus faecium (33.33%), Enterococcus hirae (13.33%), and Enterococcus avium (3.33%). The isolates exhibited high resistance to tetracycline (55.6%), erythromycin (31.1%), and ampicillin (30%). However, all of the isolates were susceptible to linezolid. Multidrug resistance (MDR) was identified in 30 (33.3%) isolates. The enterococci AMR-associated genes ermB, ermA, tetM, tetL, vanA, cat, and pbp5 were identified in 24 (26.6%), 11 (12.2%), 39 (43.3%), 34 (37.7%), 1 (1.1%), 4 (4.4%), and 23 (25.5%) isolates, respectively. Of the 90 enterococci, 21 (23.3%), 27 (30%), and 36 (40%) isolates showed the presence of cylA, gelE, and agg virulence-associated genes, respectively. Seventy-three (81.1%) isolates exhibited biofilm formation. A statistically significant correlation was obtained for biofilm formation versus the MAR index and MDR. Multi-locus sequence typing (MLST) identified eleven and eight different STs for E. faecalis and E. faecium, respectively. Seven different rep-family plasmid genes (rep1–2, rep3, rep5–6, rep9, and rep11) were detected in the MDR enterococci. Two-thirds (20/30; 66.6%) of the enterococci were positive for one or two rep-families. In conclusion, the results show that healthy backyard chickens could act as a reservoir for MDR and virulent Enterococcus spp. Thus, an effective antimicrobial stewardship program and further studies using a One Health approach are required to investigate the role of backyard chickens as vectors for AMR transmission to humans.

Excess mortality attributable to antimicrobial-resistant bacterial bloodstream infection at a tertiary-care hospital in Indonesia

The burden of antimicrobial-resistant (AMR) infections in low and middle-income countries (LMICs) is largely unknown. Here, we evaluate attributable mortality of AMR infections in Indonesia. We used routine databases of the microbiology laboratory and hospital admission at Dr. Wahidin Sudirohusodo Hospital, a tertiary-care hospital in South Sulawesi from 2015 to 2018. Of 77,752 hospitalized patients, 8,341 (10.7%) had at least one blood culture taken. Among patients with bacteriologically confirmed bloodstream infections (BSI), the proportions of patients with AMR BSI were 78% (81/104) for third-generation cephalosporin-resistant (3GCR) Escherichia coli, 4% (4/104) for 3GCR plus carbapenem-resistant E. coli, 56% (96/171) for 3GCR Klebsiella pneumoniae, 25% (43/171) for 3GCR plus carbapenem-resistant K. pneumoniae, 51% (124/245) for methicillin-resistant Staphylococcus aureus, 48% (82/171) for carbapenem-resistant Acinetobacter spp., and 19% (13/68) for carbapenem-resistant Pseudomonas aeruginosa. Observed in-hospital mortality of patients with AMR BSI was 49.7% (220/443). Compared with patients with antimicrobial-susceptible BSI and adjusted for potential confounders, the excess mortality attributable to AMR BSI was -0.01 (95% CI: -15.4, 15.4) percentage points. Compared with patients without a BSI with a target pathogen and adjusted for potential confounders, the excess mortality attributable to AMR BSI was 29.7 (95%CI: 26.1, 33.2) percentage points. This suggests that if all the AMR BSI were replaced by no infection, 130 (95%CI: 114, 145) deaths among 443 patients with AMR BSI might have been prevented. In conclusion, the burden of AMR infections in Indonesian hospitals is likely high. Similar large-scale evaluations should be performed across LMICs to inform interventions to mitigate AMR-associated mortality.

Prehospital delay is an important risk factor for mortality in community-acquired bloodstream infection (CA-BSI): a matched case-control study

OBJECTIVES

The aim of this study was to identify prehospital and early hospital risk factors associated with 30-day mortality in patients with blood culture-confirmed community-acquired bloodstream infection (CA-BSI) in Sweden.

METHODS

A retrospective case-control study of 1624 patients with CA-BSI (2015-2016), 195 non-survivors satisfying the inclusion criteria were matched 1:1 with 195 survivors for age, gender and microorganism. All forms of contact with a healthcare provider for symptoms of infection within 7 days prior CA-BSI episode were registered. Logistic regression was used to analyse risk factors for 30-day all-cause mortality.

RESULTS

Of the 390 patients, 61% (115 non-survivors and 121 survivors) sought prehospital contact. The median time from first prehospital contact till hospital admission was 13 hours (6-52) for non-survivors and 7 hours (3-24) for survivors (p<0.01). Several risk factors for 30-day all-cause mortality were identified: prehospital delay OR=1.26 (95% CI: 1.07 to 1.47), p<0.01; severity of illness (Sequential Organ Failure Assessment score) OR=1.60 (95% CI: 1.40 to 1.83), p<0.01; comorbidity score (updated Charlson Index) OR=1.13 (95% CI: 1.05 to 1.22), p<0.01 and inadequate empirical antimicrobial therapy OR=3.92 (95% CI: 1.64 to 9.33), p<0.01. In a multivariable model, prehospital delay >24 hours from first contact remained an important risk factor for 30-day all-cause mortality due to CA-BSI OR=6.17 (95% CI: 2.19 to 17.38), p<0.01.

CONCLUSION

Prehospital delay and inappropriate empirical antibiotic therapy were found to be important risk factors for 30-day all-cause mortality associated with CA-BSI. Increased awareness and earlier detection of BSI in prehospital and early hospital care is critical for rapid initiation of adequate management and antibiotic treatment.

Initial Specimen Diversion Device® Reduces Blood Culture Contamination and Vancomycin Use in Academic Medical Center

BACKGROUND

In suspected bloodstream infections, accurate blood culture results are critical to timely diagnoses and appropriate antibiotic administration.

AIM

An Initial Specimen Diversion Device®, Steripath®, (Magnolia Medical Technologies, Seattle, WA) was evaluated for efficacy in reducing blood culture contamination at Brooke Army Medical Center (6.8% six-month contamination rate prior to intervention) in a six-month quality improvement project.

METHODS

Blood cultures in the emergency department were collected using either Steripath® or the standard method. 20 mL of blood was cultured into an aerobic and anaerobic medium and incubated for five days using an automated microbial detection system immediately after collection. Positive bottles were Gram stained and plated. Rapid molecular PCR identification was performed on all first positive bottles within a blood culture set for each admission or ED visit. Speciation was deduced during antimicrobial sensitivity testing using the Vitek-2 instrument.

FINDINGS

Seven (7/1016, 0.69%) contamination events occurred when using Steripath® vs. 53 (53/800, 6.6%) contamination events when using the standard method. Steripath® use was associated with a 90% lower incidence of blood culture contamination vs. the standard method. Post-study, Steripath® use was implemented as standard practice hospital-wide, and a retrospective data analysis attributed a 31.4% decrease in vancomycin days of therapy to Steripath® adoption.

CONCLUSION

Using Steripath® significantly decreased blood culture contamination events for bacterial bloodstream infections compared to the standard method. Subsequent adoption of Steripath® reduced overall vancomycin usage. With widescale implementation Steripath® could bolster antibiotic stewardship, mitigating antibiotic resistance caused by unnecessary antibacterial treatments.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Retapamulin Activity Against Pediatric Strains of Mupirocin-resistant Methicillin-resistant Staphylococcus aureus

Retapamulin activity against 53 isolates obtained from a mupirocin-resistant community-acquired methicillin-resistant Staphylococcus aureus pediatric disease cluster was evaluated using broth microdilution. All strains were susceptible to retapamulin with minimum inhibitory concentrations ≤ 0.5 μg/mL. DNA sequence analysis of rplC and cfr identified one rplC strain variant that did not demonstrate reduced phenotypic susceptibility to retapamulin. These results demonstrate that retapamulin may be a useful alternative therapy for mupirocin-resistant community-acquired methicillin-resistant S. aureus, especially in disease clusters.

The New Challenge for Heart Endocarditis: From Conventional Prosthesis to New Devices and Platforms for the Treatment of Structural Heart Disease

Infective endocarditis is a sinister condition with considerable morbidity and mortality. Its relevance in the current era is compounded by the increased use of implanted devices such as replacement valves or cardiac implantable electronic devices. These infections are caused by multiple different bacteria with different virulence, pathogenicity, and antimicrobial resistance. Unlike in native endocarditis, the presence of foreign tissue permits sustenance by inflammatory and thrombotic processes as the artificial surfaces promote inflammatory responses and hypercoagulability. Prevention of these infections has been suggested with the use of homografts in combination with antibiotics. Others have attempted to use "low fouling coats" with little clinical success thus far. The use of antibiotic prophylaxis plays a pivotal part in reducing the incidence of prosthesis-related endocarditis. This remains especially crucial with the increasing use of transcatheter heart valve therapies. The widespread use of cardiac implantable electronic devices such as permanent pacemakers, implantable cardioverter defibrillators, and cardiac resynchronization therapy devices has also heralded a noticeable increase in cases of infectious endocarditis affecting complex equipment which can be difficult to treat. Multimodality strategies are needed with input from surgeons and cardiologists to ensure treatment is both prompt and successful, tailored to the individual needs of the patients.

Threats of antibiotic resistance: an obliged reappraisal

We are living in a society of fear, where the objectivity in estimating risks is distorted by the media and the interested parties. During more than half of a century, the feeling of antibiotic resistance as an apocalyptic phenomenon able to push our society to the high mortality rates caused by infectious diseases in the dark pre-antibiotic ages has been steadily rising. However, at the current status of modern medicine, at least in the high-medium income countries, mortality by lack of efficacy of the antibiotic armamentarium in the therapy of infections is a problem, but not a catastrophe. The threat of antibiotic resistance has many other aspects than failures of therapy in the individual patient. Among them, the increase in the frequency of severe and potentially lethal infections, as bacteremia, the population biology alterations of the healthy microbiota, the global acceleration of bacterial evolution by selecting natural genetic tools mediating microbial interactions, and, most importantly, by modifying the equilibrium and composition of environmental microbial communities. All these threats have huge implications for human health as members of a Biosphere entirely rooted in a menaced microbiosphere.

Nosocomial Infections: Pathogenicity, Resistance and Novel Antimicrobials

Background. The fight against the spread of infectious diseases creates the problem of resistance to pathogens and the most resistant of them – the propagators of nosocomial infections – are formed in hospitals because of a number of reasons. The solution of the problem lies in different areas, but the search of new effective means for the treatment of such diseases remains relevant right today. The shortest way to do this is to find the "pain points" of the pathogens themselves, i.e. the factors of their pathogenicity and resistance to which the action of novel antiseptics should be directed. Objective. We aimed to analyse and evaluate the main factors of pathogenicity and resistance of pathogens of nosocomial infections to determine modern approaches to the development of novel antimicrobials. Methods. Search and systematization of new scientific data and results concerning pathogenic factors of microbial pathogens that can be used as targets for the action of drugs. Results. Over the last 10–20 years, due to the development of new research methods in biology, it has become possible to clarify the features and additional conditions for the detection of pathogenic factors of nosocomial infections. Additional mechanisms of manifestation of resistance, adhesiveness, invasiveness, transmission of signs, secretion of toxins by pathogens are shownthat determines the general increase of their resistance to the action of currently used means. The general idea of ​​creating antiseptics that will not increase the resistance of pathogens can now be implemented by using substances with multidirectional or indirect mechanisms of action that minimally affect the metabolism of the cell and significantly reduce its resistance and pathogenicity. Conclusions. Factors of pathogenicity of propagators of nosocomial infections and mechanisms of their implementation can be considered as the main targets for the action of novel antiseptics that will inhibit the spread of pathogens without increasing their resistance. The promising substances for such drugs, among other things, are bacteriophages and their modifications, enzybiotics, immunobiotics, autoinducer inhibitors, quorum sensing-system inhibitors, b-lactamase inhibitors and others. Some of these substances in combination with the new generation of antibiotics significantly enhance their effectiveness and together they are able to overcome the resistance of even multidrug-resistant pathogens.

Burden of Antimicrobial Resistance: Compared to What?

The increased focus on the public health burden of antimicrobial resistance (AMR) raises conceptual challenges, such as determining how much harm multidrug-resistant organisms do compared to what, or how to establish the burden. Here, we present a counterfactual framework and provide guidance to harmonize methodologies and optimize study quality. In AMR-burden studies, 2 counterfactual approaches have been applied: the harm of drug-resistant infections relative to the harm of the same drug-susceptible infections (the susceptible-infection counterfactual); and the total harm of drug-resistant infections relative to a situation where such infections were prevented (the no-infection counterfactual). We propose to use an intervention-based causal approach to determine the most appropriate counterfactual. We show that intervention scenarios, species of interest, and types of infections influence the choice of counterfactual. We recommend using purpose-designed cohort studies to apply this counterfactual framework, whereby the selection of cohorts (patients with drug-resistant, drug-susceptible infections, and those with no infection) should be based on matching on time to infection through exposure density sampling to avoid biased estimates. Application of survival methods is preferred, considering competing events. We conclude by advocating estimation of the burden of AMR by using the no-infection and susceptible-infection counterfactuals. The resulting numbers will provide policy-relevant information about the upper and lower bound of future interventions designed to control AMR. The counterfactuals should be applied in cohort studies, whereby selection of the unexposed cohorts should be based on exposure density sampling, applying methods avoiding time-dependent bias and confounding.

Antibiotic strategies and clinical outcomes for patients with carbapenem-resistant Gram-negative bacterial bloodstream infection

Carbapenem-resistant Gram-negative bacterial bloodstream infection (CRGNB-BSI) has become a rapidly growing global threat with limited antibiotic options and significant mortality. The aim of this study was to explore the antibiotic strategies and clinical outcomes of patients with CRGNB-BSI in Western China. We retrospectively investigated the demographic, microbiological and clinical characteristics of 355 patients with CRGNB-BSI from 2012-2017. Treatment failure and 28-day in-hospital mortality rates were 49.3% (175/355) and 23.7% (84/355), respectively. The most frequently isolated micro-organism was Acinetobacter baumannii (58.6%; 208/355). Patients with treatment failure had higher procalcitonin and interleukin-6 levels (P < 0.05). High-dosage tigecycline therapy (200 mg loading dose followed by 100 mg every 12 h) was not superior to standard tigecycline dosing (P > 0.05). Multivariable analysis revealed that multiple organ dysfunction syndrome (MODS) (OR = 2.226, 95% CI 1.376-3.602; P = 0.001) and intensive care unit (ICU) admission (OR = 3.116, 95% CI 1.905-5.097; P = 0.000) were independent risk factors for treatment failure, whereas monotherapy (OR = 0.386, 95% CI 0.203-0.735; P = 0.004) had a protective effect. Survival analysis revealed that inappropriate therapy, MODS and ICU admission were associated with a higher 28-day in-hospital mortality rate (P < 0.001). Combination antimicrobial therapy was not superior to monotherapy (P = 0.387). This study demonstrates that appropriate therapy is significantly associated with lower treatment failure and 28-day in-hospital mortality rates. Tigecycline might not be a suitable option for CRGBN-BSI. Patients with MODS and admitted to the ICU had poor clinical outcomes.

Mortality attributable to third-generation cephalosporin resistance in Gram-negative bloodstream infections in African hospitals: a multi-site retrospective study

Background

Bloodstream infections (BSI) caused by Enterobacteriaceae show increasing frequency of resistance to third-generation cephalosporin (3GC) antibiotics on the African continent but the mortality impact has not been quantified.

Methods

We used historic data from six African hospitals to assess the impact of 3GC resistance on clinical outcomes in Escherichia coli and Klebsiella pneumoniae BSI. We matched each bacteraemic patient to two uninfected patients. We compared outcomes between 3GC-susceptible and 3GC-resistant BSI and their respective uninfected controls using Cox regression models.

Results

For 1431 E. coli BSI patients, we matched 1152 (81%) 3GC-susceptible and 279 (19%) 3GC-resistant cases to 2263 and 546 uninfected inpatient controls. For 1368 K. pneumoniae BSI patients, we matched 502 (37%) 3GC-susceptible and 866 (63%) 3GC-resistant cases to 982 and 1656 uninfected inpatient controls. We found that 3GC-resistant E. coli had similar hazard ratios (HRs) for in-hospital mortality over their matched controls as compared to susceptible infections over their controls (ratio of HRs 1.03, 95% CI 0.73–1.46). Similarly, 3GC-resistance in K. pneumoniae BSI was not associated with mortality (ratio of HR 1.10, 95% CI 0.80–1.52). Estimates of mortality impact varied by site without a consistent pattern.

Conclusions

In a retrospective analysis, including the use of matched uninfected patients, there did not appear to be an impact of 3GC-resistance on mortality in E. coli or K. pneumoniae BSI in African hospitals, as compared with susceptible BSI with equivalent species. Better information on the actual use of antibiotics in treating infections in African hospitals would improve these impact estimates.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Increasing proportion of vancomycin-resistance among enterococcal bacteraemias in Switzerland: a 6-year nation-wide surveillance, 2013 to 2018

Background

Vancomycin-resistant enterococci (VRE), mostly Enterococcus faecium, are multidrug-resistant microorganisms that can cause nosocomial infections. VRE has increased throughout many European countries, but data from Switzerland are scarce.

Aim

The aim of this work was to characterise the epidemiology of enterococcal bacteraemias in Switzerland with a focus on VRE.

Methods

In this observational study, we retrospectively investigated bacteraemias from 81 healthcare institutions from January 2013 to December 2018 using data from the Swiss Centre for Antibiotic Resistance. Only the first blood isolate with E. faecalis or E. faecium from an individual patient was considered. We analysed the annual incidences of enterococcal bacteraemias and determined the proportion of VRE over time. We also assessed epidemiological factors potentially associated with VRE bacteraemia.

Results

We identified 5,369 enterococcal bacteraemias, of which 3,196 (59.5%) were due to E. faecalis and 2,173 (40.5%) to E. faecium. The incidence of enterococcal bacteraemias increased by 3.2% per year (95% confidential interval (CI): 1.6–4.8%), predominantly due to a substantial increase in E. faecalis bacteraemic episodes. Vancomycin resistance affected 30 (1.4%) E. faecium and one E. faecalis bacteraemic episodes. Among all E. faecium bacteraemias, the proportion of vancomycin-resistant isolates increased steadily from 2013 to 2018 (2% per year; 95% CI: 1.5–2.9%). No independent epidemiological factor for higher prevalence of vancomycin-resistant E. faecium bacteraemias was identified.

Conclusions

Vancomycin-resistant E. faecium bacteraemias remain infrequent in Switzerland. However, an important increase was observed between 2013 and 2018, highlighting the need for implementing active surveillance and targeted prevention strategies in the country.

Bioassay-Directed Isolation of Antibacterial Metabolites from an Arthropod-Derived Penicillium chrysogenum

Bioassay-directed isolation of secondary metabolites from an extract of Penicillium chrysogenum TJ403-CA4 isolated from the medicinally valuable arthropod Cryptotympana atrata afforded five new and 10 known compounds (1-15). All the compounds (except 14) belong to a minor class of highly rigid 6-5-5-5-fused tetracyclic cyclopiane-type diterpenes known to be exclusively produced by members of the Penicillium genus. The structures and absolute configurations of the new compounds (1-5) were elucidated by extensive spectroscopic analyses, including HRESIMS and 1D and 2D NMR, single-crystal X-ray diffraction, and comparison of the experimental electronic circular dichroism data. Compounds 1 and 2 represent the first examples of cyclopianes bearing a C-20 carboxyl group; compound 3 represents the first example of a cyclopiane with a gem-hydroxymethyl group; compound 4 represents the second example of a cyclopiane bearing a hydroxy group at C-7; compound 5 represents the first example of a cyclopiane bearing a hydroxy group at C-8. Compounds 2 and 3 exhibited activity against MRSA, with MIC values of 4.0 and 2.0 μg/mL, respectively. In addition, the structure-antibacterial activity relationship (SAR) of compounds 1-15 is discussed.

Risk Factors for Mortality of Inpatients with Pseudomonas aeruginosa Bacteremia in China: Impact of Resistance Profile in the Mortality

Purpose

Pseudomonas aeruginosa bacteremia presents a severe challenge to hospitalized patients. However, to date, the risk factors for mortality among inpatients with P. aeruginosa bacteremia in China remain unclear.

Patients and Methods

This retrospective multicenter study was performed to analyze 215 patients with culture-confirmed P. aeruginosa bacteremia in five healthcare centers in China during the years 2012–2019.

Results

Of 215 patients with P. aeruginosa bacteremia, 61 (28.4%) died during the study period. Logistic multivariable analysis revealed that cardiovascular disease (OR=3.978, P=0.001), blood transfusion (OR=5.855, P<0.001) and carbapenem-resistant P. aeruginosa (CRPA) phenotype (OR=4.485, P=0.038) constituted the independent risk factors of mortality. Furthermore, both CRPA and multidrug-resistant P. aeruginosa (MDRPA) phenotypes were found to be significantly associated with 5-day mortality (Log-rank, P<0.05).

Conclusion

This study revealed a high mortality rate amongst hospitalized patients with P. aeruginosa bacteremia, and those with cardiovascular diseases, CRPA and MDRPA phenotypes, should be highlighted and given appropriate management in China.

Healthcare resources attributable to methicillin-resistant Staphylococcus aureus orthopedic surgical site infections

The number of orthopedic surgeries is increasing as populations steadily age, but surgical site infection (SSI) rates remain relatively consistent. This study aimed to quantify the healthcare resources attributable to methicillin-resistant Staphylococcus aureus (MRSA) SSIs in orthopedic surgical patients. The analysis was conducted using a national claims database comprising data from almost all Japanese residents. We examined patients who underwent any of the following surgeries between April 2012 and March 2018: amputation (AMP), spinal fusion (FUSN), open reduction of fracture (FX), hip prosthesis (HPRO), knee prosthesis (KPRO), and laminectomy (LAM). Propensity score matching was performed to identify non-SSI control patients, and generalized estimating equations were used to estimate the differences in outcomes between the case and control groups. The numbers of MRSA SSI cases (infection rates) ranged from 64 (0.03%) to 1,152 (2.33%). MRSA SSI-attributable increases in healthcare expenditure ranged from $11,630 ($21,151 vs. $9,521) for LAM to $35,693 ($50,122 vs. $14,429) for FX, and increases in hospital stay ranged from 40.6 days (59.2 vs. 18.6) for LAM to 89.5 days (122.0 vs. 32.5) for FX. In conclusion, MRSA SSIs contribute to substantial increases in healthcare resource utilization, emphasizing the need to implement effective infection prevention measures for orthopedic surgeries.

Antibiotic Resistant Bacterial Pathogens Associated with Blood Stream Infections and Urinary Tract Infections among Intensive Care Unit Patients

Blood Stream Infection (BSI) and Urinary Tract Infection (UTI) being leading causes of morbidity and mortality represent a common complication among critically ill patients. During the last decade, clinicians have observed a rising occurrence of BSIs due to bacterial resistance. Likewise, catheter-associated UTI is a main cause of morbidity and mortality affecting all age groups. Coliforms happen to be the prominent pathogens among our ICU admitted patients. It was alarming to notice 42.9% resistance to tigecycline among K. pneumoniae isolated from blood. K. pneumoniae isolates cultured from urine of ICU patients uniformly displayed 75% resistance to ciprofloxacin, ceftriaxone, cefoxitin and cefepime. Interestingly, it is of respite to observe 85.7% K. pneumoniae isolated from blood and 75% K. pneumoniae isolated from urine being susceptible to a conventional antibiotic, gentamicin. Escherichia coli isolated from urine were 100% susceptible to carbapenems and 91.75% were susceptible to tigecycline. Overall, 90% of Pseudomonas aeruginosa were susceptible to nitrofurantoin. The rapid spread of these MDR pathogens demands for national and regional guidelines. Policies to treat ICU related infections in UAE should be designed based on local microbiological data and resistance profiles of pathogens.

Impact of national guidelines for antimicrobial stewardship to reduce antibiotic use in upper respiratory tract infection and gastroenteritis

Objective:

To examine whether the issue and dissemination of national guidelines in the Manual of Antimicrobial Stewardship had an impact on reducing antibiotic use for acute respiratory tract infection (ARTI) and gastroenteritis.

Method:

An interrupted time-series analysis was performed using a large nationwide database from June 2016 to June 2018. Outpatients with ARTI or gastroenteritis aged ≥6 years were identified. The outcome measures were any antibiotic use and broad-spectrum antibiotic use. The season-adjusted changes in the rate of antibiotic prescriptions for 2 periods before and after the guideline issue date were examined.

Results:

There were 13,177,735 patients with ARTI and 300,565 patients with gastroenteritis during the study period. Among patients with ARTI, there was a significant downward trend in antibiotic use during the 2-year study period (−0.06% per week; 95% CI, −0.07% to −0.04%). However, there was no significant change in trends of antibiotic use between the pre-issue period and post-issue period (trend difference, −0.01% per week; 95% CI, −0.10% to 0.07%). Similarly, for patients with gastroenteritis, there was no significant change in the trends of antibiotic use between the pre-issue period and post-issue period (trend difference, −0.02% per week; 95% CI, −0.04% to 0.01%). Similar associations were observed in analyses for broad-spectrum antibiotic use.

Conclusions:

Despite the issue of national guidelines to promote the appropriate use of antibiotics, there were no significant changes in trends of antibiotic use for outpatients with ARTI or gastroenteritis between the pre-issue and post-issue periods.

Zero or More: Methodological Challenges of Counting and Estimating Deaths Related to Antibiotic-resistant Infections

Estimates of the number of deaths from antimicrobial-resistant (AMR) infections are important data for clinicians and public health officials advocating for resources to prevent and treat these infections. The aims of this article are to describe the various approaches to calculating deaths from AMR infections, to compare the tally of deaths by each approach, and to explain how to interpret the results. Currently, none of the 3 methods employed by vital statistics systems to count deaths from specific causes (underlying cause of deaths, multiple causes of death, and avoidable deaths) count deaths from AMR infections. These deaths can be estimated by 4 approaches: case-fatality rate, infection-related mortality, and excess mortality using controls with antibiotic-susceptible infections or controls without antibiotic-resistant infections. When encountering discrepant estimates of AMR-related deaths, it is important to consider which method was used and whether it was the right method to answer the question being asked.

Prevalence of and rationale for antimicrobial prescription during ambulatory care visits in Japan: a prospective, multicentre, cross-sectional study

OBJECTIVE

To determine the rate of outpatient antimicrobial use and the rationale for antimicrobial prescription.

DESIGN

A prospective, multicentre, cross-sectional study.

SETTING

Ambulatory care settings at community general hospitals.

PARTICIPANTS

A total of 1972 consecutive ambulatory visits by 1952 patients were included from 2 February 2020 to 13 February 2020. Visits resulting in hospital admission and regularly scheduled visits were excluded.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of ambulatory visits resulting in antimicrobial drug prescriptions. The secondary outcomes were the reasons for antimicrobial drug prescription and the proportion of unnecessary antimicrobial prescriptions among all antimicrobial drugs used for treatment.

RESULTS

The mean patient age was 53.8 (SD 25.8) years old, and the proportion of women was 52.6%. A total of 162 antimicrobial drugs were prescribed in 153 (7.8%) visits. The most common antimicrobial drugs were penicillins (n=48, 29.6%), followed by third-generation cephalosporins (n=35, 21.6%) and quinolones (n=20, 12.4%). Among all the antimicrobial drugs prescribed, 125 (77.2%), 18 (11.1%) and 11 (6.8%) were used for infection treatment, wound prophylaxis and surgical prophylaxis, respectively. Of the 125 antimicrobial drugs used for infection treatment, 60 (48.0%) were judged to be unnecessary.

CONCLUSIONS

One in every 13 ambulatory visits resulted in antimicrobial use in Japan. Three-fourths of the prescribed antimicrobial drugs were used for infection treatment, but approximately half of those drugs may have been unnecessary. Further efforts to reduce unnecessary antimicrobial drug use are needed.

TRIAL REGISTRATION NUMBER

UMIN000039360.

Impact of comprehensive molecular testing to reduce antibiotic use in community-acquired pneumonia (RADICAP): a randomised, controlled, phase IV clinical trial protocol

INTRODUCTION

Community-acquired pneumonia (CAP) continues to be a major health problem worldwide and is one of the main reasons for prescribing antibiotics. However, the causative agent is often not identified, resulting in antibiotic overtreatment, which is a key driver of antimicrobial resistance and adverse events. We aim to test the hypothesis that comprehensive molecular testing, compared with routine microbiological testing, would be effective in reducing antibiotic use in patients with CAP.

METHODS AND ANALYSIS

We will perform a randomised, controlled, open-label clinical trial with two parallel groups (1:1) at two tertiary hospitals between 2020 and 2022. Non-severely immunosuppressed adults hospitalised for CAP will be considered eligible. Patients will be randomly assigned to receive either the experimental diagnosis (comprehensive molecular testing plus routine microbiological testing) or standard diagnosis (only microbiological routine testing). The primary endpoint will be antibiotic consumption measured as days of antibiotic therapy per 1000 patient-days. Secondary endpoints will be de-escalation to narrower antibiotic treatment, time to switch from intravenous to oral antibiotics, days to reaching an aetiological diagnosis, antibiotic-related side effects, length of stay, days to clinical stability, intensive care unit admission, days of mechanical ventilation, hospital readmission up to 30 days after randomisation and death from any cause by 48 hours and 30 days after randomisation. We will need to include 440 subjects to be able to reject the null hypothesis that both groups have equal days of antibiotic therapy per 1000 patient-days with a probability >0.8.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Ethics Committee of Bellvitge Hospital (AC028/19) and from the Spanish Medicines and Medical Devices Agency, and it is valid for all participating centres under existing Spanish legislation. Results will be presented at international meetings and will be made available to patients, their caregivers and funders.

TRIAL REGISTRATION NUMBER

ClinicalTrials: NCT04158492. EudraCT: 2018-004880-29.

Attributable mortality of antibiotic resistance in gram-negative infections in the Netherlands: a parallel matched cohort study

OBJECTIVES

Antibiotic resistance in Gram-negative bacteria has been associated with increased mortality. This was demonstrated mostly for third-generation cephalosporin-resistant (3GC-R) Enterobacterales bacteraemia in international studies. Yet, the burden of resistance specifically in the Netherlands and created by all types of Gram-negative infection has not been quantified. We therefore investigated the attributable mortality of antibiotic resistance in Gram-negative infections in the Netherlands.

METHODS

In eight hospitals, a sample of Gram-negative infections was identified between 2013 and 2016, and separated into resistant and susceptible infection cohorts. Both cohorts were matched 1:1 to non-infected control patients on hospital, length of stay at infection onset, and age. In this parallel matched cohort set-up, 30-day mortality was compared between infected and non-infected patients. The impact of resistance was then assessed by dividing the two separate risk ratios (RRs) for mortality attributable to Gram-negative infection.

RESULTS

We identified 1954 Gram-negative infections, of which 1190 (61%) involved Escherichia coli, 210 (11%) Pseudomonas aeruginosa, and 758 (39%) bacteraemia. Resistant Gram-negatives caused 243 infections (12%; 189 (78%) 3GC-R Enterobacterales, nine (4%) multidrug-resistant P. aeruginosa, no carbapenemase-producing Enterobacterales). Subsequently, we matched 1941 non-infected controls. After adjustment, point estimates for RRs comparing mortality between infections and controls were similarly higher than 1 in case of resistant infections and susceptible infections (1.42 (95% confidence interval 0.66-3.09) and 1.32 (1.06-1.65), respectively). By dividing these, the RR reflecting attributable mortality of resistance was calculated as 1.08 (0.48-2.41).

CONCLUSIONS

In the Netherlands, antibiotic resistance did not increase 30-day mortality in Gram-negative infections.

Antibacterial Photodynamic Inactivation of Antibiotic-Resistant Bacteria and Biofilms with Nanomolar Photosensitizer Concentrations

Gram-negative bacteria and bacteria in biofilms are very difficult to eradicate and are the most antibiotic-resistant bacteria. Therapeutic alternatives less susceptible to mechanisms of resistance are urgently needed to respond to an alarming increase of resistant nosocomial infections. Antibacterial photodynamic inactivation (PDI) generates oxidative stress that triggers multiple cell death mechanisms that are more difficult to counteract by bacteria. We explore PDI of multidrug-resistant bacterial strains collected from patients and show how positive charge distribution in the photosensitizer drug impacts the efficacy of inactivation. We demonstrate the relevance of size for drug diffusion in biofilms. The designed meso-imidazolyl porphyrins of small size with positive charges surrounding the macrocycle enabled the inactivation of bacteria in biofilms by 6.9 log units at 5 nM photosensitizer concentration and 5 J cm^-2, which offers new opportunities to treat biofilm infections.

Screening of Indonesian peat soil bacteria producing antimicrobial compounds

The development and world-wide spread of multidrug-resistant (MDR) bacteria have a high concern in the medicine, especially the extended-spectrum of beta-lactamase (ESBL) producing Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA). There are currently very limited effective antibiotics to treat infections caused by MDR bacteria. Peat-soil is a unique environment in which bacteria have to compete each other to survive, for instance, by producing antimicrobial substances. This study aimed to isolate bacteria from peat soils from South Kalimantan Indonesia, which capable of inhibiting the growth of Gram-positive and Gram-negative bacteria. Isolates from peat soil were grown and identified phenotypically. The cell-free supernatant was obtained from broth culture by centrifugation and was tested by agar well-diffusion technique against non ESBL-producing E. coli ATCC 25922, ESBL-producing E. coli ATCC 35218, methicillin susceptible Staphylococcus aureus (MSSA) ATCC 29,213 and MRSA ATCC 43300. Putative antimicrobial compounds were separated using SDS-PAGE electrophoresis and purified using electroelution method. Antimicrobial properties of the purified compounds were confirmed by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In total 28 isolated colonies were recovered; three (25PS, 26PS, and 27PS) isolates produced proteins with strong antimicrobial activities against both reference strains. The substance of proteins from three isolates exerted strong antimicrobial activity against ESBL-producing E. coli ATCC 35,218 (MIC = 2,80 µg/mL (25PS), 3,76 µg/mL (26PS), and 2,41 µg/mL (27PS), and MRSA ATCC 43,300 (MIC = 4,20 µg/mL (25PS), 5,65 µg/mL (26PS), and 3,62 µg/mL (27PS), and also had the ability bactericidal properties against the reference strains. There were isolates from Indonesian peat which were potentials sources of new antimicrobials.

Ceftazidime, Carbapenems, or Piperacillin-tazobactam as Single Definitive Therapy for Pseudomonas aeruginosa Bloodstream Infection: A Multisite Retrospective Study

BACKGROUND

The optimal antibiotic regimen for Pseudomonas aeruginosa bacteremia is controversial. Although β-lactam monotherapy is common, data to guide the choice between antibiotics are scarce. We aimed to compare ceftazidime, carbapenems, and piperacillin-tazobactam as definitive monotherapy.

METHODS

A multinational retrospective study (9 countries, 25 centers) including 767 hospitalized patients with P. aeruginosa bacteremia treated with β-lactam monotherapy during 2009-2015. The primary outcome was 30-day all-cause mortality. Univariate and multivariate, including propensity-adjusted, analyses were conducted introducing monotherapy type as an independent variable.

RESULTS

Thirty-day mortality was 37/213 (17.4%), 42/210 (20%), and 55/344 (16%) in the ceftazidime, carbapenem, and piperacillin-tazobactam groups, respectively. Type of monotherapy was not significantly associated with mortality in either univariate, multivariate, or propensity-adjusted analyses (odds ratio [OR], 1.14; 95% confidence interval [CI], 0.52-2.46, for ceftazidime; OR, 1.3; 95% CI, 0.67-2.51, for piperacillin-tazobactam, with carbapenems as reference in propensity adjusted multivariate analysis; 542 patients). No significant difference between antibiotics was demonstrated for clinical failure, microbiological failure, or adverse events. Isolation of P. aeruginosa with new resistance to antipseudomonal drugs was significantly more frequent with carbapenems (36/206 [17.5%]) versus ceftazidime (25/201 [12.4%]) and piperacillin-tazobactam (28/332 [8.4%] (P = .007).

CONCLUSIONS

No significant difference in mortality, clinical, and microbiological outcomes or adverse events was demonstrated between ceftazidime, carbapenems, and piperacillin-tazobactam as definitive treatment of P. aeruginosa bacteremia. Higher rates of resistant P. aeruginosa after patients were treated with carbapenems, along with the general preference for carbapenem-sparing regimens, suggests using ceftazidime or piperacillin-tazobactam for treating susceptible infection.