The changing epidemiology of Staphylococcus aureus bloodstream infection: a multinational population-based surveillance study

Global trends in staphylococcus aureus-related lower respiratory infections from 1990 to 2021: findings from the 2021 global burden of disease report

BACKGROUND

Lower respiratory infections (LRIs) represent a significant global health issue, especially affecting low- and middle-income countries. In this study, we explored the mortality and disability-adjusted life years (DALYs) associated with Staphylococcus aureus-related LRIs from 1990 to 2021, highlighting trends by age, sex, and Socio-Demographic Index (SDI).

METHODS

Data were derived from the 2021 Global Burden of Disease (GBD) database. Temporal trends in age-standardized mortality rates (ASMR) and disability-adjusted life years (DALYs) rates (ASDR) for S. aureus-related LRIs were analyzed based on the average annual percent change (AAPC), in terms of sex, 20-age groups, 21 regions, 204 countries, and 5 SDI quintiles.

RESULTS

In 2021, S. aureus-related LRIs contributed to 423,837 deaths (95% UI: 382,183-458,926), a 67.56% increase since 1990. In comparison, the global ASMR was 5.43 per 100,000 (95% UI: 4.89-5.90), and the ASDR was 156.80 per 100,000 (95% UI: 139.44-176.08), both exhibiting a declining trend compared to 1990. Rates were higher in low SDI regions, with Central Sub-Saharan Africa reporting the highest ASMR, while Eastern Europe had the lowest. Among the 204 countries analyzed, Zimbabwe recorded high ASMR and ASDR, at 24.84 (95% UI: 19.44-30.16) and 754.34 (95% UI: 591.05-923.06), respectively.

CONCLUSIONS

Although the global ASMR and ASDR decreased in 2021, the number of deaths from S. aureus-related LRIs significantly increased driven by the growing population and proportion of aged individuals. Additionally, the emergence of multidrug-resistant strains has made treatment more complex, particularly in low SDI regions, highlighting the urgent need for more targeted strategies, therapies, and vaccines.

Bloodstream infections with emphasis on Methicillin-resistant Staphylococcus aureus at the University of Gondar Comprehensive Specialized and Referral Hospital, Northwest Ethiopia

BACKGROUND

Staphylococcus aureus is the most common cause of bloodstream infections worldwide. Methicillin-resistant S. aureus is becoming more prevalent in bacteremia and septicemia cases. Thus, this study determined Staphylococcal bacteremia, Methicillin-resistant S. aureus infections, and antimicrobial susceptibility patterns of the isolates in Northwest Ethiopia.

METHODS AND MATERIALS

This retrospective cross-sectional study was conducted on all age bloodstream suspected patients at the University of Gondar Comprehensive Specialized and Referral Hospital from January 1th 2022 to June 30th, 2022. Data were collected using a designed data extraction tool. Blood samples were collected and inoculated to a sterile Tryptic Soya Broth. Bottles with bacterial growth were subcultured to blood agar, chocolate agar, MacConkey agar, and mannitol salt agar plates. Antimicrobial susceptibility testing was performed using the Kirby Bauer disc diffusion technique. The data were entered using Epi-info version 7 and exported to SPSS version 20 for analysis.

RESULTS

Among 1200 patients included in this study, 719 (59.9%) were males. The prevalence of S. aureus and Methicillin-resistant S. aureus was 26.2% (111/424) and 68.5% (76/111), respectively. The blood culture growth rate was 35.3% (424/1200). Among the isolated organisms, Gram-positive cocci account for 217 (51.2%) and Gram-negative bacilli were 173 (41.0%). Among S. aureus isolates, 63.7% were sensitive to gentamicin and 91.9% were resistant to penicillin. A high prevalence of bacteremia was found in males (60.1%) and ward locations at the neonatal intensive care unit (57.1%). Specifically, Methicillin-resistant S. aureus was highly prevalent in males, followed by pediatric age groups, and neonatal intensive care unit, which were 59.2%, 56.6%, and 44.7%, respectively.

CONCLUSION

In this study, the prevalence of Methicillin-resistant S. aureus bacteremia was high, indicating its spread in hospital settings such as intensive care units. This requires routine detection, molecular characterization of mecA gene, and improved infection prevention at the healthcare facility.

The safety and efficacy of a single dose of oral azithromycin given in labour to prevent skin and soft tissue infections in young infants in Fiji: a randomised controlled trial

BACKGROUND

Prophylactic azithromycin in pregnancy has been shown to lower infections in birthing parents and newborns, particularly skin and soft tissue infections (SSTIs) which are common in Fiji. We aimed to determine the safety and efficacy of 2 g of oral azithromycin administered during labour on infant SSTIs.

METHODS

This blinded, randomised placebo-control trial included healthy, pregnant adults and their infants presenting for delivery at a tertiary hospital in Suva, Fiji. Participants in labour were randomly assigned a single dose of 2 g of oral azithromycin or placebo in a 1:1 ratio, stratified by ethnicity. Active and placebo drugs were identical to mask treatment allocation. The primary outcome was cumulative incidence of infant SSTIs by 3 months of age. Intention-to-treat analysis was used and included participants with SSTI data collected at all visits. Safety outcomes were described as percentages by arm at specified time points.

RESULTS

From June 2019 to January 2022, 2110 pregnant persons were enrolled and randomised, with 1059 and 1063 births in the azithromycin and placebo groups, respectively. 1671 infants were included in the primary analysis (816 in azithromycin and 855 in placebo group). We found a 27% decrease in infant SSTIs in the azithromycin group (5.8%; 95% CI 4.4-7.6) compared to placebo (7.8%; 95% CI 6.2-9.8), but the 95% confidence interval crossed the null value (RR 0.73; 95% CI 0.51-1.06). We observed similar numbers of serious adverse events in both arms, and no cases of infant hypertrophic pyloric stenosis.

CONCLUSIONS

There was a modest relative reduction in infant SSTIs but this was small in absolute terms with no statistically discernible difference. Our findings do not support routine intrapartum azithromycin prophylaxis for this outcome alone. However, the rates of SSTIs highlight the importance of prevention and timely treatment in Fiji.

TRIAL REGISTRATION

2019-04-18, ClinicalTrials.gov identifier: NCT03925480.

Research and predictive analysis of the disease burden of bloodstream infectious diseases in China

BACKGROUND

Bloodstream Infection(BSI) are one of the leading causes of infection-related mortality worldwide. However, epidemiological data related to BSI in China remain very limited.

METHODS

Based on the Global Burden of Disease(GBD) database, a systematic analysis was conducted on the epidemic trends, pathogen spectrum, and the current status of Antimicrobial Resistance(AMR) related to BSI in China for the year 2021. Additionally, an Autoregressive Integrated Moving Average(ARIMA) time series model was constructed to predict the trend of the disease burden associated with BSI in China from 2022 to 2035.

RESULTS

In terms of pathogens, the top five pathogens causing deaths due to BSI in China are as follows: Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. There are significant differences in the pathogens causing BSI across different age groups. The disease burden is heaviest in the elderly population aged 70 and above. Among children under five years old, Staphylococcus aureus, Streptococcus pneumoniae, and Candida species are predominant. From 1990 to 2021, although there has been a gradual decline in mortality rates due to BSI across different age groups (with an approximately 52.4% reduction in age-standardized rates), the disease burden of BSI increases with age. This is especially evident in the population aged 70 and above, where the burden of disease is significantly higher than in other age groups. For instance, in 2021, the mortality rate for individuals aged 70-74 was 149.29 (per 100 K), while for those aged 95 and older, the mortality rate reached as high as 896.71 (per 100 K). On a global scale, the disease burden caused by BSI in China is at a moderate level. According to time series model projections, the mortality burden of BSI in China shows a complex trend toward 2035: the crude mortality rate across all age groups is expected to increase by approximately 14.26%, whereas the age-standardized mortality rate and Disability-Adjusted Life Years(DALYs) are projected to decrease significantly. Notably, the mortality burden is expected to decline most prominently in the 70 + and under 5 age groups, while the 25-44 age group is projected to see minimal change. Conversely, the mortality rates for the 5-49 age group are anticipated to increase slightly.

CONCLUSION

Staphylococcus aureus and Escherichia coli are key pathogens contributing to the high mortality burden of BSI. Additionally, the heavy burden associated with AMR poses significant challenges to clinical treatment. From 1990 to 2021, the age-standardized mortality rate mortality of BSI patients is gradually decreasing, and the change in BSI mortality will be mainly affected by the changes in population size and age structure. The forecast analysis for 2022-2035 finds that the death burden of the elderly will be the heaviest, and the mortality of people aged 5-49 years will increase slightly. BSI and its related health problems are still major challenges and need continuous attention.

CLINICAL TRIAL

Inapplicability.

Management of methicillin-resistant Staphylococcus aureus bloodstream infections: a comprehensive narrative review of available evidence focusing on current controversies and the challenges ahead

INTRODUCTION

Bloodstream infections (BSIs) caused by Staphylococcus aureus are common worldwide, representing one of the most relevant issues in clinical infectious diseases practice. In particular, BSIs by methicillin-resistant S. aureus (MRSA-BSI) are still today a challenge since mortality burden remains elevated although decades of research.

AREAS COVERED

The following topics regarding MRSA-BSI were reviewed and discussed by resorting to best available evidence retrieved from PubMed/MEDLINE up to October 2024: i) epidemiology; ii) microbiology; iii) classification, with a focus on complicated and not complicated forms; iv) the structured approach to the patient; v) pharmacokinetics and pharmacodynamics of the main antimicrobial options; vi) controversies regarding the best therapeutic approach.

EXPERT OPINION

Despite ongoing efforts to better stratify and manage MRSA-BSI, there is no universally accepted classification system accurately distinguishing between uncomplicated/low risk and complicated/high risk forms. Biomarkers such as interleukin(IL)-10 hold promise in order to enable a more precise stratification, premise for an appropriate treatment plan. There is a theoretical rationale for implementing a combination therapy including a beta-lactam agent upfront, especially for patients considered at higher risk of unfavorable outcomes, but further data are necessary, and the same applies to newer adjuvants. Novel microbiological techniques may help in guiding antimicrobial duration.

Management of Staphylococcus aureus Bacteremia: A Review

Importance

Staphylococcus aureus, a gram-positive bacterium, is the leading cause of death from bacteremia worldwide, with a case fatality rate of 15% to 30% and an estimated 300 000 deaths per year.

Observations

Staphylococcus aureus bacteremia causes metastatic infection in more than one-third of cases, including endocarditis (≈12%), septic arthritis (7%), vertebral osteomyelitis (≈4%), spinal epidural abscess, psoas abscess, splenic abscess, septic pulmonary emboli, and seeding of implantable medical devices. Patients with S aureus bacteremia commonly present with fever or symptoms from metastatic infection, such as pain in the back, joints, abdomen or extremities, and/or change in mental status. Risk factors include intravascular devices such as implantable cardiac devices and dialysis vascular catheters, recent surgical procedures, injection drug use, diabetes, and previous S aureus infection. Staphylococcus aureus bacteremia is detected with blood cultures. Prolonged S aureus bacteremia (≥48 hours) is associated with a 90-day mortality risk of 39%. All patients with S aureus bacteremia should undergo transthoracic echocardiography; transesophageal echocardiography should be performed in patients at high risk for endocarditis, such as those with persistent bacteremia, persistent fever, metastatic infection foci, or implantable cardiac devices. Other imaging modalities, such as computed tomography or magnetic resonance imaging, should be performed based on symptoms and localizing signs of metastatic infection. Staphylococcus aureus is categorized as methicillin-susceptible (MSSA) or methicillin-resistant (MRSA) based on susceptibility to β-lactam antibiotics. Initial treatment for S aureus bacteremia typically includes antibiotics active against MRSA such as vancomycin or daptomycin. Once antibiotic susceptibility results are available, antibiotics should be adjusted. Cefazolin or antistaphylococcal penicillins should be used for MSSA and vancomycin, daptomycin, or ceftobiprole for MRSA. Phase 3 trials for S aureus bacteremia demonstrated noninferiority of daptomycin to standard of care (treatment success, 53/120 [44%] vs 48/115 [42%]) and noninferiority of ceftobiprole to daptomycin (treatment success, 132/189 [70%] vs 136/198 [69%]). Source control is a critical component of treating S aureus bacteremia and may include removal of infected intravascular or implanted devices, drainage of abscesses, and surgical debridement.

Conclusions and relevance

Staphylococcus aureus bacteremia has a case fatality rate of 15% to 30% and causes 300 000 deaths per year worldwide. Empirical antibiotic treatment should include vancomycin or daptomycin, which are active against MRSA. Once S aureus susceptibilities are known, MSSA should be treated with cefazolin or an antistaphylococcal penicillin. Additional clinical management consists of identifying sites of metastatic infection and pursuing source control for identified foci of infection.

Halogenated 3-Nitro-2H-Chromenes as Potential Agents Against Multidrug-Resistant Bacteria

Introduction/Objectives: Nosocomial infections caused by S. aureus and S. epidermidis resistant strains are an important cause of morbidity and mortality worldwide. Due to the increasing rate of resistance to conventional antibiotics, the discovery of new antibiotic drugs is crucial to keep pace with the evolution of these pathogenic bacterial species. Methods: The 3-nitro-2H-chromene moiety is present in several compounds with potent antibacterial activity; based on these previous studies, we report herein the synthesis of 20 new 2-aryl-3-nitro-2H-chromene derivatives and the evaluation of their antibacterial potential in vitro. Results: Mono-halogenated nitrochromenes showed moderate anti-staphylococcal activity with MIC values of 8-32 μg/mL, whereas tri-halogenated 3-nitro-2H-chromenes displayed potent anti-staphylococcal activities with MIC values of 1-8 μg/mL. Notably, 2-(4-bromophenyl)-6-bromo-8-chloro-3-nitro-2H-chromene 5s was the best antibacterial agent in the series against multidrug-resistant strains of S. aureus and S. epidermidis with MIC values of 4 μg/mL and 1-4 μg/mL, respectively. Conclusions: nitrochromene 5s shows a good safety profile, so it can be considered as a lead for further development.

Early cytokine signatures and clinical phenotypes discriminate persistent from resolving MRSA bacteremia

BACKGROUND

Staphylococcus aureus bacteremia (SAB) is a prevalent life-threatening infection often caused by methicillin-resistant S. aureus (MRSA). Up to 30% of SAB patients fail to clear infection even with gold-standard anti-MRSA antibiotics. This phenomenon is termed antibiotic-persistent MRSA bacteremia (APMB). The mechanisms driving APMB are complex and involve host phenotypes significantly impacting the immune response. Thus, defining early immune signatures and clinical phenotypes that differentiate APMB from antibiotic resolving (AR)MB could aid therapeutic success.

METHODS

We assessed 38 circulating cytokines and chemokines using affinity proteomics in 74 matched pairs of vancomycin-treated SAB cases identified as ARMB or APMB after 5 days of blood culture.

RESULTS

Unsupervised hierarchical clustering segregated APMB from ARMB based on differential levels of IL-10, IL-12p40, IL-13, CCL4, and TGFα. Additionally, CXCL1, CCL22 and IL-17A significantly differed between APMB and ARMB when correlated with diabetes, dialysis, metastatic infection, or cardiac vegetation. Combining immune signatures with these relevant clinical phenotypes sharply increased accuracy of discriminating APMB outcome to 79.1% via logistic regression modeling. Finally, classification-regression tree analysis revealed explicit analyte thresholds associated with APMB outcome at presentation especially in patients with metastatic infection.

CONCLUSIONS

Collectively, this study identifies previously unrecognized cytokine and chemokine signatures that distinguish APMB and ARMB at presentation and in the context of host clinical characteristics associated with increased disease severity. Validation of a biomarker signature that accurately predicts outcomes could guide early therapeutic strategies and interventions to reduce risks of persistent SAB that are associated with worsened morbidity and mortality.

Molecular epidemiology and clinical characteristics of Staphylococcus aureus bacteremia in Japanese adults

INTRODUCTION

Staphylococcus aureus bacteremia (SAB), especially when caused by methicillin-resistant S. aureus (MRSA), is of considerable clinical importance. In recent years, the proportion of MRSA among S. aureus has decreased, and a relative increase in the proportion of methicillin-susceptible S. aureus (MSSA) has been observed. It is therefore necessary to consider both MRSA and MSSA when assessing the microbiological and clinical significance of SAB.

MATERIALS AND METHODS

We included SAB cases from the Nara Medical University Hospital between January 2015 and February 2017. We performed drug susceptibility testing, toxicity gene analysis, multilocus sequence typing (MLST), and polymerase chain reaction-based open reading frame typing (POT) of stored strains to integrate clinical and bacteriological characteristics.

RESULTS

There were 90 cases during the experimental period (42 MRSA and 48 MSSA), with 30-day mortality rates of 19 % for MRSA and 10.4 % for MSSA. Deaths were more frequently complicated by septic shock and disseminated intravascular coagulation. MLST studies showed that ST8, ST764, ST1, and ST15 were prevalent in the MRSA group, whereas ST5, ST188, and ST12 were prevalent in MSSA. Infective endocarditis cases had a long time from onset to the initiation of effective antimicrobials and were all MSSA. MLST and POT results correlated well, and POT appeared to have better discriminatory power.

CONCLUSIONS

The severity and mortality of SAB, along with the microbiological characteristics of causative isolates, vary by location and time. Continued studies integrating clinical and microbiological investigations are thus needed.

Genomic characteristics and molecular epidemiology of MRSA from medical centers in Mexico: Results from the Invifar network

INTRODUCTION

The methicillin-resistant Staphylococcus aureus (MRSA) genome varies by geographical location. This study aims to determine the genomic characteristics of MRSA using whole-genome sequencing (WGS) data from medical centers in Mexico and to explore the associations between antimicrobial resistance genes and virulence factors.

METHODS

This study included 27 clinical isolates collected from sterile sites at eight centers in Mexico in 2022 and 2023. Antibiotic susceptibility testing was performed using VITEK 2. In addition, WGS was performed using a NovaSeq platform, and a bioinformatic analysis was conducted using several tools.

RESULTS

In this study, 21 strains were CC5, five were CC8, and one was CC93. Moreover, six strains were identified as ST5(CC5)-MRSA-IIa- t895, four strains were found to be ST1011(CC5)-MRSA-IIa-t895, five strains were found to be ST1011(CC5)-MRSA-IIa-t9364, one strain was found to be ST1011(CC5)-MRSA-IIa-t8116, another was found to be ST1011(CC5)-MRSA-IIa-t62, three were found to be ST8(CC8)-MRSA-IVa-t8, one strain was ST5(CC5)-MRSA-IVa-t2, one strain was as ST93(CC93)-MRSA-IVa-t3949, two strains were ST9003(CC8)-MRSA-IVa-t18492, and three strains were ST9034(CC5)-MRSA-V-t2. All SCCmec IIa strains showed resistance to levofloxacin and ciprofloxacin, and all but two strains were resistant to clindamycin. Among the strains that harbored the type IIa cassette, most had the aadD, blaZ, and ermA_SDS genes and the erm A gene. Multiple genes for adhesion, enzymes, immune evasion, and secretion system were detected, regardless of SCCmec type. Of the SCCmec IVa strains, most harbored the Panton-Valentine leukocidin encoding genes.

CONCLUSION

In this study, the most frequently detected CC was CC5, followed by CC8, and CC93, and the most frequently detected MRSA ST was ST1011, followed by ST5. Most SCCmec elements were found to be type IIa, followed by type IVa. High MIC values were observed for ciprofloxacin, erythromycin, and clindamycin, particularly within SCCmec IIa. Of the SCCmec IVa strains, most harbored the lukS-PV and lukF-PV genes.

Prospective Observational Study of De-Escalation of Empirical Antibiotics in Fiji's National Hospital

Background: Antimicrobial resistance is a global health threat and Fiji is not exempt. The appropriate prescribing and timely de-escalation of antibiotics as an integral component of antimicrobial stewardship has been recently introduced in Fiji to help curb antimicrobial resistance through de-escalation, leading to a reduced opportunity for the induction of resistance. Objectives: To assess whether empirical antibiotics are being adjusted in a timely fashion in patients admitted with a diagnosis of suspected infection in the Colonial War Memorial Hospital( CMWH) over three months. Method: The study was undertaken on patients admitted to the acute medical ward and intensive care unit of the CWMH in Suva (Fiji's largest hospital). A total of 474 patients were prospectively enrolled at admission when prescribed empiric antibiotic therapy for suspected infections between February and April 2019. Results: A total of 356 patients admitted to the Acute Medical Ward and 118 admitted to the Intensive Care Unit were prescribed empiricalantibiotics. These 474 patients were prospectively observed to determine the factors influencing the extent and the timing of antibiotic de-escalation. Only 137 (29%) patients had their antibiotic regimen de-escalated in the first 72 h post-admission based on their microbiological results, whereas, 207 (42%) were de-escalated more than 72 h after admission (OR = 0.5, 95% CI 0.3-0.89; p < 0.016). Conclusions: At CWMH, antibiotic de-escalation is slow and may be improved by quicker laboratory reporting, greater access to laboratory results for prescribers, and the availability of a wider range of narrow-spectrum antibiotics to assist de-escalation.

Biosynthesis and health promoting traits of green synthesized cobalt oxide nanoparticles

Nanomedical applications have increased significantly. This work aimed to fabricate and characterize cobalt oxide nanoparticles (CoOnps) synthesized biologically via aqueous Alhagi maurorum extract and evaluate their cytotoxic and antimicrobial impacts. Green-synthesized CoOnps were prepared and analyzed using UV-Vis spectrophotometer UV-vis, Scanning electron microscopy (SEM), Transmission electron microscopy TEM, Energy dispersive X-ray analysis EDAX, Fourier transform infrared, FTIR, and X-ray diffraction (XRD). In vitro traits of green-synthesized CoOnps were studied on ovarian cancer cells (SKOV3) using a Sulforhodamine B (SRB) method. The cytotoxic effect and IC50 were estimated. Moreover, concentrations of 10, 30, 40, 70, 100, 200, 300, 400 and 500 μg/mL CoOnps were applied to investigate their antimicrobial effect against Listeria, Staphylococcus aureus and Streptococcus as gram +ve pathogenic bacteria, Bifidobacterium bifidum 2203, Bifidobacterium bifidum LMG 10,645, Bifidobacterium breve LMC 017, Bifidobacterium angulatum 2238 and Bifidobacterium longum ATCC 15,707 as probiotics, E. coli as gram -ve bacterial model and yeast strain Candida albicans. CoOnps showed anti-ovarian cancer effects at 24.02 μg/mL. Furthermore, it exerted antimicrobial activity versus Listeria, Streptococcus, S. aureus, and E. coli were 31.66 ± 0.88, 24.33 ± 2.08, 25.66 ± 0.33, and 33.00 ± 6.08; however, they did not suppress the growth of Candida albicans and all tested Bifidobacterial strains up to concentrations of 500 μg/mL with significant difference compared to all concentrations p < 0.05. Green synthesis of CoOnps is a low-cost, eco-friendly and easily prepared method. Its impressive features as cytotoxic SKOV3, a cell line ovarian cancer and antibacterial effect for some gram +ve and -ve bacteria, besides maintaining probiotics, could candidate them as competitive agents for medical, pharmacological, agricultural and food applications.

Mortality and genetic diversity of antibiotic-resistant bacteria associated with bloodstream infections: a systemic review and genomic analysis

BACKGROUND

Bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) represent a significant disease burden worldwide. However, a comprehensive analysis of the mortality rates and global epidemiology across different ARB species associated with BSIs is currently lacking.

METHODS

We conducted a systematic review by searching multiple databases (PubMed, Web of Science, and Embase) for studies reporting ARB-related BSIs data up to June 19, 2023. Additionally, we performed genomic analyses of all the publicly available bacterial genomes associated with BSIs to elucidate their molecular characteristics.

RESULTS

A total of 322 articles (N = 90,672 patients) were included in this study. For 28 or 30-day mortality, the overall mortality rate for all ARB species was 32.0%. Among them, antibiotic-resistant A. baumannii exhibited the highest rate (54.2%). And the top three ARB types with the highest mortality rates at 28 or 30-day were CefeR-PA (cefepime-resistant P. aeruginosa), CREC (carbapenem-resistant E. coli), and CRAB (carbapenem-resistant A. baumannii), all exceeding 50%, whereas the mortality rates of CRKP (carbapenem-resistant K. pneumoniae), CRPA (carbapenem-resistant P. aeruginosa), and VREfm (vancomycin-resistant E. faecium) were at least 40%. A total of 9,289 ARB genomes related to BSIs were acquired from the NPDIB database and are predominantly distributed in North America, Asia, and Europe. Antibiotic resistance gene (ARG) analysis identified a total of 613 ARG subtypes from the top six ARB species, with numbers ranging from 48 for E. faecium to 253 for K. pneumoniae. Furthermore, specific clones of ARB species were strongly associated with BSIs, such as ST131 in E. coli, ST8, and ST5 in S. aureus, ST2 in A. baumannii, and ST11 and ST258 in K. pneumoniae.

CONCLUSION

ARB contributed to the burden of BSIs, with a 30-day all-cause mortality rate as high as 32.0%. ARB strains causing BSIs display high genetic diversity, highlighting the importance of continuing to monitor high-risk clones to control the development of antibiotic resistance. Differences in ARGs patterns require tailored antibiotic management strategies for each ARB species.

Immunoinformatic approach for multi-epitope vaccine design against Staphylococcus aureus based on hemolysin proteins

Staphylococcus aureus is a common bacterium that causes a variety of infections in humans. This microorganism produces several virulence factors, including hemolysins, which contribute to its disease-causing ability. The treatment of S. aureus infections typically involves the use of antibiotics. However, the emergence of antibiotic-resistant strains has become a major concern. Therefore, vaccination against S. aureus has gained attention as an alternative approach. Vaccination has the advantage of stimulating the immune system to produce specific antibodies that can neutralize bacteria and prevent infection. However, developing an effective vaccine against S. aureus has proven to be challenging. This study aimed to use in silico methods to design a multi-epitope vaccine against S. aureus infection based on hemolysin proteins. The designed vaccine contained four B-cell epitopes, four CTL epitopes, and four HTL epitopes, as well as the ribosomal protein L7/L12 and pan-HLA DR-binding epitope, included as adjuvants. Furthermore, the vaccine was non-allergenic and non-toxic with the potential to stimulate the TLR2-, TLR-4, and TLR-6 receptors. The predicted vaccine exhibited a high degree of antigenicity and stability, suggesting potential for further development as a viable vaccine candidate. The population coverage of the vaccine was 94.4 %, indicating potential widespread protection against S. aureus. Overall, these findings provide valuable insights into the design of an effective multi-epitope vaccine against S. aureus infection and pave the way for future experimental validations.

Whole-of-Life Inclusion in Bayesian Adaptive Platform Clinical Trials

Importance

There is a recognized unmet need for clinical trials to provide evidence-informed care for infants, children and adolescents. This Special Communication outlines the capacity of 3 distinct trial design strategies, sequential, parallel, and a unified adult-pediatric bayesian adaptive design, to incorporate children into clinical trials and transform this current state of evidence inequity. A unified adult-pediatric whole-of-life clinical trial is demonstrated through the Staphylococcus aureus Network Adaptive Platform (SNAP) trial.

Observations

Bayesian methods provide a framework for synthesizing data in the form of a probability model that can be used in the design and analysis of a clinical trial. Three trial design strategies are compared: (1) a sequential adult-pediatric bayesian approach that involves a separate, deferred pediatric trial that incorporates existing adult trial data into the analysis model to potentially reduce the pediatric trial sample size; (2) a parallel adult-pediatric bayesian trial whereby separate pediatric enrollment occurs in a parallel trial, running alongside an adult randomized clinical trial; and (3) a unified adult-pediatric bayesian adaptive design that supports the enrollment of both children and adults simultaneously in a whole-of-life bayesian adaptive randomized clinical trial. The SNAP trial whole-of-life design uses a bayesian hierarchical model that allows information sharing (also known as borrowing) between trial age groups by linking intervention effects of children and adults, thereby improving inference in both groups.

Conclusion and Relevance

Bayesian hierarchical models may provide more precision for estimates of safety and efficacy of treatments in trials with heterogenous populations compared to traditional methods of analysis. They facilitate the inclusion of children in clinical trials and a shift from children deemed therapeutic orphans to the vision of no child left behind in clinical trials to ensure evidence for clinical practice exists across the life course. The SNAP trial provides an example of a bayesian adaptive whole-of-life inclusion design that enhances trial population inclusivity and diversity overall, as well as generalizability and translation of findings into clinical practice.

Atopic Dermatitis: A Disorder of both Adults and Children with Varying Longitudinal Course

The longitudinal course of atopic dermatitis (AD) is heterogeneous and complex. While previously thought to be a childhood disorder, recent studies demonstrated that childhood-onset AD may take several different courses that may involve persistence into adulthood becoming a lifelong condition. Other patients only demonstrated adult-onset AD. Different factors may play a role in the timing of AD onset. Assessing the longitudinal course also involves understanding the changing temporal pattern of AD. Understanding the dynamic course of AD is important in identifying individualized treatment recommendations for patients.

A Machine Learning-Based Risk Score for Prediction of Infective Endocarditis Among Patients With Staphylococcus aureus Bacteremia-The SABIER Score

BACKGROUND

Early risk assessment is needed to stratify Staphylococcus aureus infective endocarditis (SA-IE) risk among patients with S. aureus bacteremia (SAB) to guide clinical management. The objective of the current study was to develop a novel risk score that is independent of subjective clinical judgment and can be used early, at the time of blood culture positivity.

METHODS

We conducted a retrospective big data analysis from territory-wide electronic data and included hospitalized patients with SAB between 2009 and 2019. We applied a random forest risk scoring model to select variables from an array of parameters, according to the statistical importance in predicting SA-IE outcome. The data were divided into derivation and validation cohorts. The areas under the curve of the receiver operating characteristic (AUCROCs) were determined.

RESULTS

We identified 15 741 SAB patients, among them 658 (4.18%) had SA-IE. The AUCROC was 0.74 (95%CI 0.70-0.76), with a negative predictive value of 0.980 (95%CI 0.977-0.983). The four most discriminatory features were age, history of infective endocarditis, valvular heart disease, and community onset.

CONCLUSIONS

We developed a novel risk score with performance comparable with existing scores, which can be used at the time of SAB and prior to subjective clinical judgment.

Conserved moonlighting protein pyruvate dehydrogenase induces robust protection against Staphylococcus aureus infection

Developing an effective Staphylococcus aureus (S. aureus) vaccine has been a challenging endeavor, as demonstrated by numerous failed clinical trials over the years. In this study, we formulated a vaccine containing a highly conserved moonlighting protein, the pyruvate dehydrogenase complex E2 subunit (PDHC), and showed that it induced strong protective immunity against epidemiologically relevant staphylococcal strains in various murine disease models. While antibody responses contributed to bacterial control, they were not essential for protective immunity in the bloodstream infection model. Conversely, vaccine-induced systemic immunity relied on γδ T cells. It has been suggested that prior S. aureus exposure may contribute to the reduction of vaccine efficacy. However, PDHC-induced protective immunity still facilitated bacterial clearance in mice previously exposed to S. aureus. Collectively, our findings indicate that PDHC is a promising serotype-independent vaccine candidate effective against both methicillin-sensitive and methicillin-resistant S. aureus isolates.

Risk of infective endocarditis and complicated infection in Staphylococcus aureus bacteremia - a retrospective cohort study on the role of bacteriuria

PURPOSE

S. aureus bacteremia (SAB) is a common and severe infection with high mortality and morbidity. The clinical relevance of the finding of concurrent S. aureus bacteriuria (SABU) is debated. The goal of this study was to analyze whether a concurrent SABU is associated with complicated SAB, infective endocarditis (IE) and mortality.

METHODS

We conducted a retrospective cohort study, reviewing medical charts of all episodes of SAB in patients > 18 years in the region of Skåne, Sweden, between 1st of January and 31st of June 2020. Episodes where a concurrent urine culture was performed were included for analysis. An episode was considered as complicated SAB if there was either attributable mortality, recurrent infection, embolic stroke, or occurrence of a complicated focus of infection.

RESULTS

During the study period, there were 279 episodes of SAB. 154 episodes met the eligibility criteria, of whom 37 (24%) had concurrent SABU. In 78 episodes (51%), the patients had a complicated SAB. There was a significantly lower proportion of complicated SAB for episodes with concurrent SABU (32%), compared to episodes without concurrent SABU (56%), p-value 0.014. Moreover, in the cohort there were 11 episodes (7.1%) of IE and a 30 days mortality rate of 16%, with no difference between the groups with or without SABU.

CONCLUSIONS

There is an association between concurrent SABU and a decreased risk for complicated SAB among patients with SAB. This study found no significant association between SABU and neither IE nor mortality for patients with SAB.

Collaborative Cross mice have diverse phenotypic responses to infection with Methicillin-resistant Staphylococcus aureus USA300

Staphylococcus aureus (S. aureus) is an opportunistic pathogen causing diseases ranging from mild skin infections to life threatening conditions, including endocarditis, pneumonia, and sepsis. To identify host genes modulating this host-pathogen interaction, we infected 25 Collaborative Cross (CC) mouse strains with methicillin-resistant S. aureus (MRSA) and monitored disease progression for seven days using a surgically implanted telemetry system. CC strains varied widely in their response to intravenous MRSA infection. We identified eight 'susceptible' CC strains with high bacterial load, tissue damage, and reduced survival. Among the surviving strains, six with minimal colonization were classified as 'resistant', while the remaining six tolerated higher organ colonization ('tolerant'). The kidney was the most heavily colonized organ, but liver, spleen and lung colonization were better correlated with reduced survival. Resistant strains had higher pre-infection circulating neutrophils and lower post-infection tissue damage compared to susceptible and tolerant strains. We identified four CC strains with sexual dimorphism: all females survived the study period while all males met our euthanasia criteria earlier. In these CC strains, males had more baseline circulating monocytes and red blood cells. We identified several CC strains that may be useful as new models for endocarditis, myocarditis, pneumonia, and resistance to MRSA infection. Quantitative Trait Locus (QTL) analysis identified two significant loci, on Chromosomes 18 and 3, involved in early susceptibility and late survival after infection. We prioritized Npc1 and Ifi44l genes as the strongest candidates influencing survival using variant analysis and mRNA expression data from kidneys within these intervals.

Staphylococcus aureus Infections and Human Intestinal Microbiota

Staphylococcus aureus (S. aureus) is a common pathogen that can cause many human diseases, such as skin infection, food poisoning, endocarditis, and sepsis. These diseases can be minor infections or life-threatening, requiring complex medical management resulting in substantial healthcare costs. Meanwhile, as the critically ignored "organ," the intestinal microbiome greatly impacts physiological health, not only in gastrointestinal diseases but also in disorders beyond the gut. However, the correlation between S. aureus infection and intestinal microbial homeostasis is largely unknown. Here, we summarized the recent progress in understanding S. aureus infections and their interactions with the microbiome in the intestine. These summarizations will help us understand the mechanisms behind these infections and crosstalk and the challenges we are facing now, which could contribute to preventing S. aureus infections, effective treatment investigation, and vaccine development.

Antimicrobial resistance prevalence in bloodstream infection in 29 European countries by age and sex: An observational study

BACKGROUND

Antibiotic usage, contact with high transmission healthcare settings as well as changes in immune system function all vary by a patient's age and sex. Yet, most analyses of antimicrobial resistance (AMR) ignore demographic indicators and provide only country-level resistance prevalence values. This study aimed to address this knowledge gap by quantifying how resistance prevalence and incidence of bloodstream infection (BSI) varied by age and sex across bacteria and antibiotics in Europe.

METHODS AND FINDINGS

We used patient-level data collected as part of routine surveillance between 2015 and 2019 on BSIs in 29 European countries from the European Antimicrobial Resistance Surveillance Network (EARS-Net). A total of 6,862,577 susceptibility results from isolates with age, sex, and spatial information from 944,520 individuals were used to characterise resistance prevalence patterns for 38 different bacterial species and antibiotic combinations, and 47% of these susceptibility results were from females, with a similar age distribution in both sexes (mean of 66 years old). A total of 349,448 isolates from 2019 with age and sex metadata were used to calculate incidence. We fit Bayesian multilevel regression models by country, laboratory code, sex, age, and year of sample to quantify resistant prevalence and provide estimates of country-, bacteria-, and drug-family effect variation. We explore our results in greater depths for 2 of the most clinically important bacteria-antibiotic combinations (aminopenicillin resistance in Escherichia coli and methicillin resistance in Staphylococcus aureus) and present a simplifying indicative index of the difference in predicted resistance between old (aged 100) and young (aged 1). At the European level, we find distinct patterns in resistance prevalence by age. Trends often vary more within an antibiotic family, such as fluroquinolones, than within a bacterial species, such as Pseudomonas aeruginosa. Clear resistance increases by age for methicillin-resistant Staphylococcus aureus (MRSA) contrast with a peak in resistance to several antibiotics at approximately 30 years of age for P. aeruginosa. For most bacterial species, there was a u-shaped pattern of infection incidence with age, which was higher in males. An important exception was E. coli, for which there was an elevated incidence in females between the ages of 15 and 40. At the country-level, subnational differences account for a large amount of resistance variation (approximately 38%), and there are a range of functional forms for the associations between age and resistance prevalence. For MRSA, age trends were mostly positive, with 72% (n = 21) of countries seeing an increased resistance between males aged 1 and 100 years and a greater change in resistance in males. This compares to age trends for aminopenicillin resistance in E. coli which were mostly negative (males: 93% (n = 27) of countries see decreased resistance between those aged 1 and 100 years) with a smaller change in resistance in females. A change in resistance prevalence between those aged 1 and 100 years ranged up to 0.51 (median, 95% quantile of model simulated prevalence using posterior parameter ranges 0.48, 0.55 in males) for MRSA in one country but varied between 0.16 (95% quantile 0.12, 0.21 in females) to -0.27 (95% quantile -0.4, -0.15 in males) across individual countries for aminopenicillin resistance in E. coli. Limitations include potential bias due to the nature of routine surveillance and dependency of results on model structure.

CONCLUSIONS

In this study, we found that the prevalence of resistance in BSIs in Europe varies substantially by bacteria and antibiotic over the age and sex of the patient shedding new light on gaps in our understanding of AMR epidemiology. Future work is needed to determine the drivers of these associations in order to more effectively target transmission and antibiotic stewardship interventions.

Molecular Epidemiological Characterization of Methicillin-Resistant Staphylococcus aureus from Bloodstream Infections in Northern Japan: Increasing Trend of CC1 and Identification of ST8-SCCmec IVa USA300-Like Isolate Lacking Arginine Catabolic Mobile Element

Methicillin-resistant Staphylococcus aureus (MRSA) is a major infectious disease pathogen, and its molecular epidemiological profile has been changing. In this study, a total of 279 MRSA isolates were collected from patients with bloodstream infection (BSI) in Hokkaido, northern main island of Japan, for a 2-year period from August 2019 to July 2021. CC5 (ST5/ST764)-MRSA-IIa (SCCmec-IIa) (47%, n = 132) and CC1 (ST1/ST2725/ST2764)-MRSA-IVa (42%, n = 116) were found to be major lineages, with CC8-MRSA-IVa being lower prevalence (5%, n = 13). CC1-MRSA-IVa showed a relatively increased proportion compared with our previous study (22%, 2017-2019). Seven isolates with SCCmec IVa (2.5%) were positive for Panton-Valentine leukocidin genes on ΦSa2usa and belonged to ST8/spa-t008/agr-I/coa-IIIa, showing genetic features of the USA300 clone. Among these isolates, six isolates harbored arginine catabolic mobile element (ACME) type I typical to the USA300 clone, while it was not detected in an isolate (strain R3-8). Whole genomic analysis of strain R3-8 revealed that its chromosome was highly similar to the USA300 strain TCH1516, but lacked ACME, carrying a plasmid genetically close to that of USA300 strains. The present study revealed increasing trend of CC1-MRSA-IV and occurrence of a novel variant of the USA300 clone among MRSA from BSI in northern Japan.

Safety and effectiveness of fifth generation cephalosporins for the treatment of methicillin-resistant staphylococcus aureus bloodstream infections: a narrative review exploring past, present, and future

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) is a major issue in healthcare, since it is often associated with endocarditis or deep site foci. Relevant morbidity and mortality associated with MRSA-BSIs forced the development of new antibiotic strategies; in particular, this review will focus the attention on fifth-generation cephalosporins (ceftaroline/ceftobiprole), that are the only ß-lactams active against MRSA.

AREAS COVERED

The review discusses the available randomized controlled trials and real-world observational studies conducted on safety and effectiveness of ceftaroline/ceftobiprole for the treatment of MRSA-BSIs. Finally, a proposal of MRSA-BSI treatment flowchart, based on fifth-generation cephalosporins, is described.

EXPERT OPINION

The use of anti-MRSA cephalosporins is an acceptable choice either in monotherapy or combination therapy for the treatment of MRSA-BSIs due to their relevant effectiveness and safety. Particularly, their use may be advisable in combination therapy in case of severe infections (including endocarditis or persistent bacteriemia) or in monotherapy in subjects at higher risk of drugs-induced toxicity with older regimens. On the contrary, caution should be taken in case of suspected/ascertained central nervous system infections due to inconsistent data regarding penetration of these drugs in cerebrospinal fluid and brain tissues.

Zinc Oxide Nanoparticles Promise Anticancer and Antibacterial Activity in Ovarian Cancer

BACKGROUND

Ovarian cancer is the most lethal cancer in gynaecology. Surgery, chemotherapy, and radiotherapy are the most often used cancer-fighting strategies. Post-surgery infection is fairly prevalent, especially among people with insufficient immunity. Zinc oxide nanoparticles (ZnOnps) have amazing biomedical features as anticancer and antibacterial agents.

METHODS

We investigated the behaviour of ZnOnps synthesized by green methods on ovarian cancers using established human ovarian cancer cell lines, besides the antibacterial action toward models of gram + ve and gram -ve bacteria. The cytotoxic effect of ZnOnps was calculated using a Sulforhodamine B (SRB) trial. Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were tested as models for gram + ve and gram -ve bacteria. The selected bacteria were subjected to concentrations of 20, 40, 80, and 100 μg/ml.

RESULTS

The synthesized ZnOnps induced 50% inhibitory concentration (IC50) at a concentration of 27.45 μg/ml. The diameter of inhibition ranged between 20.16 ± 0.16 and 27 ± 0.57 mm for S. aureus and 25.66 ± 0.33 to 31 ± 0.33 mm for E. coli. ZnOnps antagonistic effect statistically differed with neomycin, cefaclor, and cefadroxil.

CONCLUSIONS

Green synthesis of ZnOnps is easily prepared, low cost, non-toxic, and eco-friendly. Their cytotoxic action on SKOV3 cells and their antibacterial characteristics pave the way to be an alternative therapy for ovarian cancer and S. aureus and E. coli infection.

Antimicrobial Peptides and Small Molecules Targeting the Cell Membrane of Staphylococcus aureus

Clinical management of Staphylococcus aureus infections presents a challenge due to the high incidence, considerable virulence, and emergence of drug resistance mechanisms. The treatment of drug-resistant strains, such as methicillin-resistant S. aureus (MRSA), is further complicated by the development of tolerance and persistence to antimicrobial agents in clinical use. To address these challenges, membrane disruptors, that are not generally considered during drug discovery for agents against S. aureus, should be explored. The cell membrane protects S. aureus from external stresses and antimicrobial agents, but membrane-targeting antimicrobial agents are probably less likely to promote bacterial resistance. Nontypical linear cationic antimicrobial peptides (AMPs), highly modified AMPs such as daptomycin (lipopeptide), bacitracin (cyclic peptide), and gramicidin S (cyclic peptide), are currently in clinical use. Recent studies have demonstrated that AMPs and small molecules can penetrate the cell membrane of S. aureus, inhibit phospholipid biosynthesis, or block the passage of solutes between the periplasm and the exterior of the cell. In addition to their primary mechanism of action (MOA) that targets the bacterial membrane, AMPs and small molecules may also impact bacteria through secondary mechanisms such as targeting the biofilm, and downregulating virulence genes of S. aureus. In this review, we discuss the current state of research into cell membrane-targeting AMPs and small molecules and their potential mechanisms of action against drug-resistant physiological forms of S. aureus, including persister cells and biofilms.

Rare and unexpected cause for retropharyngeal abscess in an immunocompetent man: metastatic community-acquired methicillin-resistant Staphylococcus aureus infection

Staphylococcus aureus causes clinical diseases ranging from mild skin infections to devastating conditions such as septic shock, endocarditis and osteomyelitis. S. aureus is a common cause of community-acquired bacteraemia. Prolonged bacteraemia may cause metastatic infection, manifesting as endocarditis, osteomyelitis and abscesses. A man in his 20s presented with a short-duration of fever and odynophagia. CT of the neck suggested a retropharyngeal abscess. Retropharyngeal abscesses are typically polymicrobial and caused by resident oral cavity flora. In the hospital, he developed shortness of breath and hypoxia. CT of the chest showed peripheral, subpleural nodular opacities raising suspicion for septic pulmonary emboli. Blood cultures demonstrated the growth of methicillin-resistant S. aureus The patient completely recovered with antibiotic therapy alone. This is a unique and rare presentation case of metastatic S. aureus bacteraemia, manifesting as a retropharyngeal abscess without any evidence of infective endocarditis on transoesophageal echocardiography.

Maurice A, Dogan TL, Ceesay B, Umukoro S, Okomo U, Nwakanma D, Roca A, Secka O, Forrest K, Garner OB. Using an Antibiogram Profile to Improve Infection Control and Rational Antimicrobial Therapy in an Urban Hospital in The Gambia, Strategies and Lessons for Low- and Middle-Income Countries

Antimicrobial resistance is a global health threat and efforts to mitigate it is warranted, thus the need for local antibiograms to improve stewardship. This study highlights the process that was used to develop an antibiogram to monitor resistance at a secondary-level health facility to aid empirical clinical decision making in a sub-Saharan African county. This retrospective cross-sectional descriptive study used 3 years of cumulative data from January 2016 to December 2018. Phenotypic data was manually imputed into WHONET and the cumulative antibiogram constructed using standardized methodologies according to CLSI M39-A4 guidelines. Pathogens were identified by standard manual microbiological methods and antimicrobial susceptibility testing was performed using Kirby-Bauer disc diffusion method according to CLSI M100 guidelines. A total of 14,776 non-duplicate samples were processed of which 1163 (7.9%) were positive for clinically significant pathogens. Among the 1163 pathogens, E. coli (n = 315) S. aureus (n = 232), and K. pneumoniae (n = 96) were the leading cause of disease. Overall, the susceptibility for E. coli and K. pneumoniae from all samples were: trimethoprim-sulfamethoxazole (17% and 28%), tetracycline (26% and 33%), gentamicin (72% and 46%), chloramphenicol (76 and 60%), and ciprofloxacin (69% and 59%), and amoxicillin/clavulanic (77% and 54%) respectively. Extended spectrum beta-lactamase (ESBL) resistance was present in 23% (71/315) vs. 35% (34/96) respectively. S. aureus susceptibility for methicillin was 99%. This antibiogram has shown that improvement in combination therapy is warranted in The Gambia.

Staphylococcus aureus induces tolerance in human monocytes accompanied with expression changes of cell surface markers

Exposure of human monocytes to lipopolysaccharide (LPS) or other pathogen-associated molecular pattern (PAMPs) induces a temporary insensitivity to subsequent LPS challenges, a cellular state called endotoxin tolerance (ET), associated with the pathogenesis of sepsis. In this study, we aimed to characterize the cellular state of human monocytes from healthy donors stimulated with Staphylococcus aureus in comparison to TLR2-specific ligands. We analyzed S. aureus induced gene expression changes after 2 and 24 hours by amplicon sequencing (RNA-AmpliSeq) and compared the pro-inflammatory response after 2 hours with the response in re-stimulation experiments. In parallel, glycoprotein expression changes in human monocytes after 24 hours of S. aureus stimulation were analyzed by proteomics and compared to stimulation experiments with TLR2 ligands Malp-2 and Pam3Cys and TLR4 ligand LPS. Finally, we analyzed peripheral blood monocytes of patients with S. aureus bloodstream infection for their ex vivo inflammatory responses towards S. aureus stimulation and their glycoprotein expression profiles. Our results demonstrate that monocytes from healthy donors stimulated with S. aureus and TLR ligands of Gram-positive bacteria entered the tolerant cell state after activation similar to LPS treatment. In particular reduced gene expression of pro-inflammatory cytokines (TNF, IL1β) and chemokines (CCL20, CCL3, CCL4, CXCL2, CXCL3 and CXCL8) could be demonstrated. Glycoprotein expression changes in monocytes tolerized by the different TLR agonists were highly similar while S. aureus-stimulated monocytes shared some of the PAMP-induced changes but also exhibited a distinct expression profile. 11 glycoproteins (CD44, CD274, DSC2, ICAM1, LAMP3, LILRB1, PTGS2, SLC1A3, CR1, FGL2, and HP) were similarly up- or downregulated in all four comparisons in the tolerant cell state. Monocytes from patients with S. aureus bacteremia revealed preserved pro-inflammatory responsiveness to S. aureus stimulation ex vivo, expressed increased CD44 mRNA but no other glycoprotein of the tolerance signature was differentially expressed.

Incidence, aetiology and temporal trend of bloodstream infections in southern Sweden from 2006 to 2019: a population-based study

BackgroundBloodstream infections (BSI) are a public health concern, and infections caused by resistant bacteria further increase the overall BSI burden on healthcare.AimTo provide a population-based estimate of BSI incidence and relate this to the forthcoming demographic ageing western population change.MethodsWe retrieved positive blood cultures taken from patients in the Skåne region, southern Sweden, 2006-2019 from the Clinical Microbiology Department database and estimated incidence rates (IR), stratified by age (0-49, 50-64, 65-79, ≥ 80 years), sex, year, and species and described antimicrobial susceptibility for Enterobacterales.ResultsWe identified 944,375 blood culture sets, and 129,274 (13.7%) were positive. After deduplication and removal of contaminants, 54,498 separate BSI episodes remained. In total, 30,003 BSI episodes (55%) occurred in men. The overall IR of BSI was 307/100,000 person-years, with an average annual increase of 3.0%. Persons ≥ 80 years had the highest IR, 1781/100,000 person-years, as well as the largest increase. Escherichia coli (27%) and Staphylococcus aureus (13%) were the most frequent findings. The proportion of Enterobacterales isolates resistant to fluoroquinolones and third generation cephalosporins increased from 8.4% to 13.6%, and 4.9% to 7.3%, (p for trend < 0.001), with the largest increase in the oldest age group.ConclusionWe report among the highest BSI IRs to date worldwide, with a higher proportion among elderly persons and males, including resistant isolates. Given expected demographic changes, these results indicate a possible substantial future BSI burden, for which preventive measures are needed.

Outpatient Parenteral Antibiotic Therapy in Older Adults

Outpatient parenteral antimicrobial therapy (OPAT) for older adults is a complex process that involves multiple stakeholders and care coordination, but it is a useful and patient-centered tool with opportunities for the treatment of complicated infections, improved patient satisfaction, and reduced health-care costs. Older age should not be an exclusion for OPAT but rather prompt the OPAT provider to thoroughly evaluate candidacy and safety. Amid the on-going COVID-19 pandemic, innovations in OPAT are needed to shepherd OPAT care into a more patient-centered, thoughtful practice, whereas minimizing harm to older patients from unnecessary health-care exposure and thus health-care associated infections.

Differences in the distribution of pathogens and antimicrobial resistance in bloodstream infections in migrants compared with non-migrants in Denmark

BACKGROUND

We wish to study disparities in bloodstream infections in migrants and non-migrants by comparing the distribution of pathogens and their resistance patterns in long-term migrants with that in non-migrants in Denmark.

METHODS

The study is based on a cohort of migrants, who received residency in Denmark between 1993 and 2015 and a control group of non-migrants. The cohort was linked to a database of bloodstream infections from 2000 to 2015 covering two regions in Denmark. First-time bloodstream infections in individuals ≥18 years of age at the time of sampling were included. We calculated odds ratios adjusted for age, sex, year of sampling, comorbidity, and place of acquisition (hospital- or community-acquired).

RESULTS

We identified 4,703 bloodstream infection cases. Family-reunified migrants and refugees had higher odds of Escherichia coli than non-migrants (OR 1.89 95%CI: 1.46-2.44 and OR 1.55 95%CI: 1.25-1.92) and lower odds of Streptococcus pneumoniae (OR 0.38 95%CI: 0.21-0.67 and OR 0.52 95%CI: 0.34-0.81). Differences in pathogen distribution were only prevalent in community-acquired bloodstream infections. Refugees had higher odds of Escherichia coli resistant to piperacillin-tazobactam, ciprofloxacin, and gentamicin compared with non-migrants. Family-reunified migrants had higher odds of Escherichia coli and other Enterobacterales resistant to ciprofloxacin.

CONCLUSIONS

Migrants had a higher proportion of community-acquired bloodstream infections with Escherichia coli as well as higher odds of bloodstream infections with resistant Escherichia coli compared with non-migrants. These novel results are relevant for improving migrant health by focussing on preventing and treating infections especially with Escherichia coli such as urinary tract and abdominal infections.

Escalation of antimicrobial resistance among MRSA part 1: focus on global spread

INTRODUCTION

Staphylococcus aureus produce numerous virulence factors that influence tissue invasion, cytotoxicity, membrane damage, and intracellular persistence allowing them to be very common human pathogens. S. aureus isolates exhibit considerable diversity though specific genotypes have been associated with antimicrobial resistance (AMR) and toxin gene profiles. MRSA is an important pathogen causing both community-acquired (CA) and healthcare-acquired (HCA) infections. Importantly, over the past several decades, both HCA-MRSA and CA-MRSA have spread all over the globe. Even more concerning is that CA-MRSA clones have disseminated into hospitals and HCA-MRSA have entered the community. Factors that enhance spread of MRSA include: poor antimicrobial stewardship and inadequate infection control. The emergence and spread of multidrug resistant (MDR) MRSA has limited therapeutic options.

AREAS COVERED

The authors discuss the escalation of MRSA, both HCA-MRSA and CA-MRSA across the globe. A literature search of MRSA was performed via PubMed (up to September 2022), using the key words: antimicrobial resistance; β-lactams; community-associated MRSA; epidemiology; infection; multidrug resistance; Staphylococcus aureus.

EXPERT OPINION

Over the past several decades, MRSA has spread all over the globe. We encourage the judicious use of antimicrobials in accordance with antimicrobial stewardship programs along with infection control measures to minimize the spread of MRSA.

Increasing trend in enterococcal bacteraemia and vancomycin resistance in a tertiary care hospital in Croatia, 2017-2021

BACKGROUND

The epidemiology of enterococcal bacteraemia has changed worldwide and vancomycin-resistant enterococci increasingly cause healthcare-associated infections) with limited treatment options. Studies show heterogeneity among countries, regions and individual hospitals.

METHODS

We retrospectively analysed enterococcal bacteraemia with Enterococcus faecalis and E. faecium at the largest hospital in Croatia, University Hospital Centre Zagreb from January 2017 to December 2021.

RESULTS

A total of 432 cases of enterococcal bacteraemia were identified with 256 (59.3%) due to E. faecalis and 176 (40.7%) to E. faecium. Enterococcal bacteraemia occurred more frequently in men (n = 270; 62.5%) and the median age of all patients was 62 years (IQR: 0-92). We found statistically significant increase in the incidence trend of bacteraemic episodes with an annual percent change of 20.9% (95% confidence interval 14.3 to 27.8; p = .002) predominantly due to an increase of E. faecalis bacteraemia. The majority of patients (362/432; 83.8%) had healthcare-associated infections and 38.0% (165/432) of patients were in the intensive care unit. The proportion of vancomycin-resistant enterococcal bacteraemia increased from 12.7% (n = 8/63) in 2017 to 25.7% (n = 29/113) in 2021, statistically significant increasing trend (p = .0455), mainly due to an increased proportion of vancomycin-resistant E. faecium (p = .0169).

CONCLUSIONS

This is the first study describing the trends in enterococcal bacteraemia and vancomycin-resistance in enterococci in Croatia. We found a rising trend in enterococcal bacteraemia and in the proportion of vancomycin resistance and identified the most vulnerable patient groups, notably intensive care unit patients.

Iron restriction induces the small-colony variant phenotype in Staphylococcus aureus

Pathogens such as Staphylococcus aureus must overcome host-induced selective pressures, including limited iron availability. To cope with the harsh conditions of the host environment, S. aureus can adapt its physiology in multiple ways. One of these adaptations is the fermenting small-colony variant (SCV) phenotype, which is known to be inherently tolerant to certain classes of antibiotics and heme toxicity. We hypothesized that SCVs might also behave uniquely in response to iron starvation since one of the major cellular uses of iron is the respiration machinery. In this study, a respiring strain of S. aureus and fermenting SCV strains were treated with different concentrations of the iron chelator, 2,2' dipyridyl (DIP). Our data demonstrate that a major impact of iron starvation in S. aureus is the repression of respiration and the induction of the SCV phenotype. We demonstrate that the SCV phenotype transiently induced by iron starvation mimics the aminoglycoside recalcitrance exhibited by genetic SCVs. Furthermore, prolonged growth in iron starvation promotes increased emergence of stable aminoglycoside-resistant SCVs relative to the naturally occurring subpopulation of SCVs within an S. aureus community. These findings may have relevance to physiological and evolutionary processes occurring within bacterial populations infecting iron-limited host environments.

[Impact of Staphylococcus aureus bacteremia in COVID-19 patients]

OBJECTIVE

The disease caused by SARS-CoV-2 (COVID-19) has been a challenge for healthcare professionals since its appearance. Staphylococcus aureus has been described as one of the main pathogens causing bacterial infections in viral pandemics. However, co- infection with S. aureus causing bacteremia in patients with COVID-19 has yet to be well studied.

METHODS

We performed a e study of S. aureus bacteremia (SAB) at Hospital Miguel Servet (Zaragoza) from March 2020 to February 2021. The clinical characteristics, mortality and risk factors of adults hospitalized patients with BSA associated COVID-19 compared to patients without COVID-19.

RESULTS

A total of 95 patients with SAB were identified. 27.3% were positive for SARS-CoV-2. SAB represented 9.9% of bacteremia, being the second agent in frequency after E. coli. Nosocomial bacteremia was more frequent in the group of COVID-19 patients. The most frequent source of BSA in these patients was the respiratory source (26.9% vs 0%; P<0.001) followed by the skin (15.5% vs 15.9%; P=1). The development of sepsis was more frequent in COVID-19 patients (61,5% vs 7,8%; P=0,336) and among them, who received dexamethasone at doses > 6 mg/day (62.5% vs. 37.5%, P<0.05).

CONCLUSIONS

Our data suggest that BSA has a negative impact on the evolution of patients with COVID-19. However, further and preferably prospective studies are required to obtain solid data on the impact of BSA on coronavirus patients.

Proline Transport and Growth Changes in Proline Transport Mutants of Staphylococcus aureus

Staphylococcus aureus is a major cause of skin/soft tissue infections and more serious infections in humans. The species usually requires the importation of proline to be able to survive. Previous work has shown that single mutations in genes that encode for proline transporters affect the ability of S. aureus to survive in vitro and in vivo. To better understand proline transport in S. aureus, double and triple gene mutant strains were created that targeted the opuD, proP, and putP genes. Single gene mutants had some effect on proline transport, whereas double mutants exhibited significantly lower proline transport. An opuD prop putP triple gene mutant displayed the lowest proline transport under low- and high-affinity conditions. To assess growth differences caused by the mutations, the same mutants were grown in brain heart infusion (BHI) broth and defined staphylococcal medium (DSM) with various concentrations of proline. The triple mutant did not grow in DSM with a low concentration of proline and grew poorly in both DSM with a high proline concentration and BHI broth. These results show that S. aureus has multiple mechanisms to import proline into the cell and knocking out three of the main proline transporters significantly hinders S. aureus growth.

Association Between Time to Appropriate Antimicrobial Treatment and 30-day Mortality in Patients With Bloodstream Infections: A Retrospective Cohort Study

BACKGROUND

Effective antimicrobial treatment is key for survival in bloodstream infection (BSI), but the impact of timing of treatment remains unclear. Our aim was to assess the association between time to appropriate antimicrobial treatment and 30-day mortality in BSI patients.

METHODS

This was a retrospective cohort study using electronic health record data from a large academic center in Sweden. Adult patients admitted between the years 2012 and 2019, with onset of BSI at the emergency department or general wards, were included. Pathogen-antimicrobial drug combinations were classified as appropriate or inappropriate based on reported in vitro susceptibilities. To avoid immortal time bias, the association between appropriate therapy and mortality was assessed with multivariable logistic regression analysis at pre-specified landmark times.

RESULTS

We included 10 628 BSI-episodes, occurring in 9192 unique patients. The overall 30-day mortality was 11.8%. No association in favor of a protective effect between appropriate therapy and mortality was found at the 1, 3 and 6 hours landmark after blood culture collection. At 12 hours, the risk of death increased with inappropriate treatment (adjusted odds ratio 1.17 [95% confidence interval {CI}, 1.01-1.37]) and continued to increase gradually at 24, 48, and 72 hours. Stratifying by high or low SOFA score generated similar odds ratios, with wider confidence intervals.

CONCLUSIONS

Delays in appropriate antimicrobial treatment were associated with increased 30-day mortality after 12 hours from blood culture collection, but not at 1, 3, and 6 hours, in BSI. These results indicate a benchmark for providing rapid microbiological diagnostics of blood cultures.

Antimicrobial Activity of Rhenium Di- and Tricarbonyl Diimine Complexes: Insights on Membrane-Bound S. aureus Protein Binding

Antimicrobial resistance is one of the major human health threats, with significant impacts on the global economy. Antibiotics are becoming increasingly ineffective as drug-resistance spreads, imposing an urgent need for new and innovative antimicrobial agents. Metal complexes are an untapped source of antimicrobial potential. Rhenium complexes, amongst others, are particularly attractive due to their low in vivo toxicity and high antimicrobial activity, but little is known about their targets and mechanism of action. In this study, a series of rhenium di- and tricarbonyl diimine complexes were prepared and evaluated for their antimicrobial potential against eight different microorganisms comprising Gram-negative and -positive bacteria. Our data showed that none of the Re dicarbonyl or neutral tricarbonyl species have either bactericidal or bacteriostatic potential. In order to identify possible targets of the molecules, and thus possibly understand the observed differences in the antimicrobial efficacy of the molecules, we computationally evaluated the binding affinity of active and inactive complexes against structurally characterized membrane-bound S. aureus proteins. The computational analysis indicates two possible major targets for this class of compounds, namely lipoteichoic acids flippase (LtaA) and lipoprotein signal peptidase II (LspA). Our results, consistent with the published in vitro studies, will be useful for the future design of rhenium tricarbonyl diimine-based antibiotics.

Early deaths associated with community-acquired and healthcare-associated bloodstream infections: a population-based study, Finland, 2004 to 2018

Background

Bloodstream infections (BSI) cause substantial morbidity and mortality.

Aim

We explored the role of causative pathogens and patient characteristics on the outcome of community-acquired (CA) and healthcare-associated (HA) BSI, with particular interest in early death.

Methods

We used national register data to identify all BSI in Finland during 2004–18. We determined the origin of BSI, patients´ underlying comorbidities and deaths within 2 or 30 days from specimen collection. A time-dependent Cox model was applied to evaluate the impact of patient characteristics and causative pathogens on the hazard for death at different time points.

Results

A total of 173,715 BSI were identified; 22,474 (12.9%) were fatal within 30 days and, of these, 6,392 (28.4%) occurred within 2 days (7.9 deaths/100,000 population). The 2-day case fatality rate of HA-BSI was higher than that of CA-BSI (5.4% vs 3.0%). Patients who died within 2 days were older than those alive on day 3 (76 vs 70 years) and had more severe comorbidities. Compared with other BSI, infections leading to death within 2 days were more often polymicrobial (11.8% vs 6.3%) and caused by Pseudomonas aeruginosa (6.2% vs 2.0%), fungi (2.9% vs 1.4%) and multidrug-resistant (MDR) pathogens (2.2% vs 1.8%), which were also predictors of death within 2 days in the model.

Conclusions

Overrepresentation of polymicrobial, fungal, P. aeruginosa and MDR aetiology among BSI leading to early death is challenging concerning the initial antimicrobial treatment. Our findings highlight the need for active prevention and prompt recognition of BSI and appropriate antimicrobial treatment.

Whole-Genome Sequencing of Staphylococcus aureus and Staphylococcus haemolyticus Clinical Isolates from Egypt

Infections caused by antibiotic-resistant Staphylococcus are a global concern. This is true in the Middle East, where increasingly resistant Staphylococcus aureus and Staphylococcus haemolyticus strains have been detected. While extensive surveys have revealed the prevalence of infections caused by antibiotic-resistant staphylococci in Europe, Asia, and North America, the population structure of antibiotic-resistant staphylococci recovered from patients and clinical settings in Egypt remains uncharacterized. We performed whole-genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital; 46 of the S. aureus genomes and all 10 of the S. haemolyticus genomes carry mecA, which confers methicillin resistance. Supplemented with additional publicly available genomes from the other parts of the Middle East (34 S. aureus and 6 S. haemolyticus), we present the largest genomic study to date of staphylococcal isolates from the Middle East. These genomes include 20 S. aureus multilocus sequence types (MLST), including 3 new ones. They also include 9 S. haemolyticus MLSTs, including 1 new one. Phylogenomic analyses of each species' core genome largely mirrored those of the MLSTs, irrespective of geographical origin. The hospital-acquired spa t037/ST239-SCCmec III/MLST CC8 clone represented the largest clade, comprising 22% of the S. aureus isolates. Like S. aureus genome surveys of other regions, these isolates from the Middle East have an open pangenome, a strong indicator of gene exchange of virulence factors and antibiotic resistance genes with other reservoirs. Our genome analyses will inform antibiotic stewardship and infection control plans in the Middle East. IMPORTANCE Staphylococci are understudied despite their prevalence within the Middle East. Methicillin-resistant Staphylococcus aureus (MRSA) is endemic to hospitals in Egypt, as are other antibiotic-resistant strains of S. aureus and S. haemolyticus. To provide insight into the strains circulating in Egypt, we performed whole-genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital. Through analysis of these genomes, as well as all available S. aureus and S. haemolyticus genomes from the Middle East (n = 40), we were able to produce a picture of the diversity in this region more complete than those afforded by traditional molecular typing strategies. For example, we identified 4 new MLSTs. Most strains harbored genes associated with multidrug resistance, toxin production, biofilm formation, and immune evasion. These data provide invaluable insight for future antibiotic stewardship and infection control within the Middle East.

Relationship between mortality and molecular epidemiology of methicillin-resistant Staphylococcus aureus bacteremia

Staphylococcus aureus is the primary cause of bacteremia, and methicillin-resistant S. aureus bacteremia is associated with a high mortality rate. Methicillin-resistant S. aureus clones are widespread worldwide, and molecular epidemiological studies are important. Therefore, this study aimed to determine the characteristics of patients who died due to methicillin-resistant S. aureus bacteremia and microbiological characteristics of methicillin-resistant S. aureus strains in a tertiary teaching hospital. This single-center, retrospective study included patients with methicillin-resistant S. aureus isolated from blood bacterial culture performed at Kyoto Prefectural University of Medicine Hospital, from October 2016 to May 2019. The data analyzed included patient background, clinical strain characteristics, and molecular epidemiology. Of 41 patients with methicillin-resistant S. aureus bacteremia (median age, 60 [28–70] years; 24 (59%) were men), and 7 (17%) died due to methicillin-resistant S. aureus bacteremia. The median age of those who died in the methicillin-resistant S. aureus bacteremia group was predominantly higher than that of those in the alive group (p = 0.03). The most common cause of methicillin-resistant S. aureus bacteremia was endovascular devices, which occurred in 20 (49%), 18 (53%), and 2 (29%) patients in the total, alive, and died groups, respectively. Bacteriological characteristics showed that type IV Staphylococcal Cassette Chromosome mec genotype was most frequently detected in the total (n = 34 [83%]), alive (n = 29 [85%]), and died (n = 5 [71%]) groups. In the molecular cluster analysis, CC8, ST8, staphylococcal Cassette Chromosome mec type IV, and community-acquired-methicillin-resistant S. aureus formed the largest groups. The diversity of methicillin-resistant S. aureus clones is evident, and it is possible that clones with new virulence factors may still emerge. In the future, it will be crucial to monitor the epidemiological trends of methicillin-resistant S. aureus to respond quickly to changes in pathogenic and clonal factors, to clarify the gene expression network by identifying old and new virulence factors.

Genome Evolution of Invasive Methicillin-Resistant Staphylococcus aureus in the Americas

Staphylococcus aureus causes a variety of debilitating and life-threatening diseases, and thus remains a challenging global health threat. S. aureus is remarkably diverse, yet only a minority of methicillin-resistant S. aureus (MRSA) clones have caused pandemic proportions of diseases. The genetic drivers of the successful dissemination of some clones across wide geographical expanses remain poorly understood. We analyzed 386 recently published MRSA genomes from bloodstream infections sampled in North, Central, and South America from 2011 to 2018. Here, we show that MRSA-associated bloodstream infections were attributable to two genetically distinct lineages. One lineage consisted almost exclusively of sequence type (ST) 8, which emerged in 1964. A second lineage emerged in 1986 and consisted of STs 5, 105, and 231. The two lineages have simultaneously disseminated across geographically distant sites. Sublineages rapidly diverged within locations in the early 2000s. Their diversification was associated with independent acquisitions of unique variants of the mobile mecA-carrying chromosomal cassette and distinct repertoires of antimicrobial resistance genes. We show that the evolution and spread of invasive multidrug-resistant MRSA in the Americas was driven by transcontinental dissemination, followed by more recent establishment and divergence of local pathogen populations. Our study highlights the need for continued international surveillance of high-risk clones to control the global health threat of multidrug resistance.

IMPORTANCE Bloodstream infections due to S. aureus cause significant patient morbidity and mortality worldwide, exacerbated by the emergence and spread of methicillin resistant S. aureus (MRSA). This study provides important insights on the evolution and long-distance geographic expansion of two distinct MRSA lineages that predominate in bloodstream infections in the past 5 decades. The success of these two lineages partly lies on their acquisition of a diverse set of antimicrobial resistance genes and of unique variants of the mobile genetic element SCCmec that carries the gene mecA conferring resistance to beta-lactams. High-risk antimicrobial resistant clones can therefore rapidly disseminate across long distances and establish within local communities within a short period of time. These results have important implications for global initiatives and local epidemiological efforts to monitor and control invasive MRSA infections and transcontinental spread of multidrug resistance.

Staphylococcus aureus adhesion to the host

Staphylococcus aureus is a pathobiont capable of colonizing and infecting most tissues within the human body, resulting in a multitude of different clinical outcomes. Adhesion of S. aureus to the host is crucial for both host colonization and the establishment of infections. Underlying the pathogen's success is a complex and diverse arsenal of adhesins. In this review, we discuss the different classes of adhesins, including a consideration of the various adhesion sites throughout the body and the clinical outcomes of each infection type. The development of therapeutics targeting the S. aureus host-pathogen interaction is a relatively understudied area. Due to the increasing global threat of antimicrobial resistance, it is crucial that innovative and alternative approaches are considered. Neutralizing virulence factors, through the development of antivirulence agents, could reduce bacterial pathogenicity and the ever-increasing burden of S. aureus infections. This review provides insight into potentially efficacious adhesion-associated targets for the development of novel decolonizing and antivirulence strategies.

Staphylococcus aureus native mitral valve endocarditis associated with bed bug bites - A case report and review of the literature

Staphylococcus aureus is a leading cause of community acquired bacteremia and infective endocarditis. S. aureus is a part of the normal skin flora in approximately one third of the human population. Infective endocarditis due to S. aureus can cause several complications and is associated with increased mortality. A 48-year-old female with no significant medical history presented with S. aureus bacteremia and native mitral valve endocarditis. Multiple cutaneous skin lesions were identified, which she reported were due to recent bed bug bites. No source of infection was found except for the skin lesions. Her hospital course was complicated by pulmonary and cerebral septic emboli, left pleural empyema, and acute renal injury. We suspected the bed bug skin bites were the most likely source of bacteremia. Bed bugs carry many human pathogens but have not been shown to be a competent vector. We did not find any literature on endocarditis associated with bed bug bites; thus, our case will be a novel finding.

Incidence Trends and Epidemiology of Staphylococcus aureus Bacteremia: A Systematic Review of Population-Based Studies

OBJECTIVES

To determine incidence trends of Staphylococcus aureus bacteremia (SAB) from population-based studies from multiple countries.

METHODS

A contemporary systematic review was conducted using Ovid Cochrane Central Register of Controlled Trials (1991+), Ovid Embase (1974+), Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE) (1946+ including epub ahead of print, in-process & other non-indexed citations), and Web of Science Core Collection (Science Citation Index Expanded 1975+ and Emerging Sources Citation Index 2015+). Two authors (J.R.H. and J.A.Q.M.) independently reviewed all studies and included those that reported population-based incidence of SAB in patients aged 18 years and older.

RESULTS

Twenty-six studies met inclusion criteria with the highest number (n=6) of studies conducted in Canada. The incidence of SAB ranged from 9.3 to 65 cases/100,000/year. The median age of patients with SAB ranged from 62 to 72 years and SAB cases were more commonly observed in men than in women. The most common infection sources were intravascular catheters and skin and soft tissue infections. SAB incidence trends demonstrated high variability for geographic regions and calendar years. Overall, there was no change in the incidence trend across all studies during the past two decades.

CONCLUSION

Multiple factors, both pros, and cons are likely responsible for the overall stable SAB incidence in countries included in this systematic review. Some of these factors vary in geographic location and prompt additional investigations from countries not included in the current review so that a more global characterization is defined.

Prevention of bacterial complications of scabies using mass drug administration: A population-based, before-after trial in Fiji, 2018-2020

BACKGROUND

Scabies is an important predisposing factor of impetigo which can lead to serious bacterial complications. Ivermectin-based mass drug administration can substantially reduce scabies and impetigo prevalence in endemic settings, but the impact on serious bacterial complications is not known.

METHODS

We conducted a before-after trial in the Northern Division of Fiji (population: 131,914) of mass drug administration for scabies control. Prospective surveillance was conducted from 2018 to 2020. Mass drug administration took place in 2019, involving two doses of oral ivermectin or topical permethrin, delivered alongside diethylcarbamazine and albendazole for lymphatic filariasis. The primary outcomes were incidence of hospitalisations with skin and soft tissue infections, and childhood invasive infections and post-streptococcal sequelae. Secondary outcomes included presentations to primary healthcare with skin infections and community prevalence of scabies and impetigo.

FINDINGS

The incidence of hospitalisations with skin and soft tissue infections was 17% lower after the intervention compared to baseline (388 vs 467 per 100,000 person-years; incidence rate ratio 0.83, 95% CI, 0.74 to 0.94; P = 0.002). There was no difference in incidence of childhood invasive infections and post-streptococcal sequelae. Incidence of primary healthcare presentations with scabies and skin infections was 21% lower (89.2 vs 108 per 1000 person-years, incidence rate ratio, IRR 0.79, 95% CI, 0.78 to 0.82). Crude community prevalence of scabies declined from 14.2% to 7.7% (cluster-adjusted prevalence 12.5% to 8.9%; prevalence ratio 0.71, 95% CI, 0.28 to 1.17). Cluster-adjusted prevalence of impetigo declined from 15.3% to 6.1% (prevalence ratio 0.4, 95% CI, 0.18 to 0.86).

INTERPRETATION

Mass drug administration for scabies control was associated with a substantial reduction in hospitalisations for skin and soft tissue infections.

FUNDING

National Health and Medical Research Council of Australia and Scobie and Claire Mackinnon Trust.