Burden of bacterial bloodstream infection-a brief update on epidemiology and significance of multidrug-resistant pathogens

Incidence, Clinical Features, and Association with Prognosis of Bloodstream Infection in Pediatric Patients After Percutaneous or Surgical Treatment for Ventricular Septal Defect or Atrial Septal Defect: A Retrospective Cohort Study

INTRODUCTION

Bloodstream infection (BSI) may occur after cardiac procedures, but this has rarely been investigated specifically in pediatric patients after percutaneous or surgical treatment for ventricular septal defect (VSD) or atrial septal defect (ASD) with recent data. The current study aimed to investigate the incidence, clinical features, and association with prognosis of BSI in this patient population.

METHODS

Pediatric patients who received percutaneous or surgical procedure for VSD or ASD between 2010 and 2018 in a large children's hospital in China were retrospectively enrolled via the Pediatric Intensive Care database, but only those who had blood culture records within 24 h after the procedure and who had no prior positive blood culture records were included. BSI after the procedure was identified by reviewing blood culture records, and baseline characteristics associated with BSI were explored by univariable logistic regression. In-hospital mortality and length of hospitalization were studied as prognostic outcomes and compared between patients with and without BSI.

RESULTS

A total of 1340 pediatric patients were included. Among them, 46 (3.43%) patients had BSI within 24 h after the procedure, of which the majority (78.26%, 36/46) were caused by Gram-positive bacteria and 65.22% (30/46) had antibiotic-resistant organisms. Age [odds ratio (OR) 0.98 per 1-month increase, 95% confidence interval (CI) 0.97-1.00, P = 0.021] and antibiotic use within 72 h before the procedure (OR 1.81, 95% CI 1.00-3.26, P = 0.049) were statistically significantly associated with developing BSI. Compared with patients without BSI, there was no statistically significant difference in in-hospital mortality (0.00% versus 0.54%, P = 1.000), but patients with BSI had statistically significantly longer length of hospitalization (median 14.51 versus 12.94 days, P = 0.006), while the association was not statistically significant after adjustment for baseline characteristics by multivariable linear regression (β = 1.73, 95% CI -0.59 to 4.04, P = 0.144).

CONCLUSION

BSI is relatively uncommon in pediatric patients after procedures for VSD or ASD, but a younger age seems a risk factor. Developing BSI appears to be associated with increased length of hospitalization but not in-hospital mortality.

Follow-up blood culture in Gram-negative bacilli bacteraemia: for whom is follow-up blood culture useful?

PURPOSE OF REVIEW

The aim of this narrative review is to examine available evidence about the diagnostic yielding of the follow-up blood cultures (FU-BCs) in patients with Gram-negative bloodstream infection (GN-BSI), the predictors of persistent GN-BSI, and the impact of the performance of FU-BCs on patient management and clinical outcome.

RECENT FINDINGS

The rate of persistent GN-BSI varies from 2.6% to 38.5%, with higher percentages in studies where FU-BCs were obtained from selected patients. Risk factors for persistent GN-BSI were analysed and prediction tools were proposed to guide physicians in the selection of patients. The impact of FU-BCs on patient management is still controversial as several authors have shown that this practice was associated with prolonged treatment duration and longer hospital stay. However, when adjusted for indication and survival bias, the performance of FU-BCs was a strong predictor of survival in large cohorts of hospitalized patients with GN-BSI. Favourable outcome seemed to be associated with higher rate of source control in GN-BSI patients managed with FU-BCs.

SUMMARY

The practice of FU-BCs in patients with GN-BSI should be individualised balancing cost/benefit ratio. The use of risk scores could be useful in selecting patients for whom FU-BCs are appropriate.

Microbiological characteristics and risk factors on prognosis associated with Acinetobacter baumannii bacteremia in general hospital: A single-center retrospective study

OBJECTIVE

Acinetobacter baumannii is one of the most important pathogenic bacteria causing nosocomial infections and has a high mortality rate. Assessment of the microbiological characteristics and risk factors on prognosis associated with A.baumannii is essential. In this study, we aimed to investigate the clinical characteristics and prognostic risk factors of patients with A.baumannii bacteremia.

PATIENTS AND METHODS

This study retrospectively analyzed the antibiotic resistance of pathogens based on the clinical data of A.baumannii bacteremia patients presented in a tertiary teaching hospital from 2017 to 2022. Logistic regression and decision tree identified the prognostic risk factors for patients with baumannemia. Kaplan-Meier method was used for survival analysis between MDR and Non-MDR groups. The area under receiver-operating characteristic curve (ROC curve) was used to compare the predictive value of the APACHE II score and Sequential Organ Failure Assessment (SOFA) score.

RESULTS

A total of 110 patients with positive A. Baumannii blood cultures were included. Most of the patients were from intensive care unit (ICU) wards. The drug sensitivity results showed that the resistance rate of A. baumannii to colistin was the lowest (1.1%), followed by tigecycline (3.6%).The survival time of MDR group was significantly shorter than that of Non-MDR group. Multivariate analysis showed that, APACHE II score and SOFA score were independent risk factors affecting the prognosis of 28 days of A.baumannii bacteremia. And both scores displayed excellent AUROCs (SOFA: 0.909, APACHE II: 0.895 in predicting 28-day mortality). The two scoring systems were highly correlated and predicted no significant difference (r 2 = 0.4410, P < 0.001). We found that SOFA > 7 and APACHE II > 21 are associated with significantly higher mortality rates.

CONCLUSION

A.baumannii bacteremia have the highest incidence in the ICU, with high drug resistance and mortality rates. The survival time of patients with MDR A. Baumannii bacteremia was significantly shortened. The SOFA score and APACHE II score can reflect the severity of A.baumannii bacteremia patients and evaluate the 28-day prognosis. In addition, for the convenience of calculation, the SOFA score may be more clinically useful than the APACHE II score in predicting the mortality rate of A.baumannii bacteremia.

Development of a Multiplex Polymerase Chain Reaction-Based DNA Lateral Flow Assay as a Point-of-Care Diagnostic for Fast and Simultaneous Detection of MRSA and Vancomycin Resistance in Bacteremia

To reduce high mortality and morbidity rates, timely and proper treatment of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection is required. A multiplex polymerase reaction (mPCR)-based DNA lateral flow assay (MBDLFA) was developed as a point-of-care diagnostic for simultaneous identification of S. aureus, methicillin resistance, and vancomycin resistance directly from blood or blood cultures. A mPCR was developed to detect nuc, mecA, and vanA/B; its sensitivity, specificity, and limit of detection (LOD) were determined. The developed reaction was further modified for use in MBDLFA and its sensitivity for detection of target genes from artificially inoculated blood samples was checked. The optimized mPCR successfully detected nuc, mecA, and vanA/B from genomic DNA of bacterial colonies with LODs of 107, 107, and 105 CFU/mL, respectively. The reaction was sensitive and specific. The optimized mPCR was used in MBDLFA that detected nuc, mecA, and vanA/B with LODs of 107, 108, and 104 CFU/mL, respectively, directly from artificially inoculated blood. The developed MBDLFA can be used as a rapid, cheap point-of-care diagnostic for detecting S. aureus, MRSA, and vancomycin resistance directly from blood and blood cultures in ~2 h with the naked eye. This will reduce morbidity, mortality, and treatment cost in S. aureus bacteremia.

Sepsityper® Kit versus In-House Method in Rapid Identification of Bacteria from Positive Blood Cultures by MALDI-TOF Mass Spectrometry

In order to further accelerate pathogen identification from positive blood cultures (BC), various sample preparation protocols to identify bacteria with MALDI-TOF MS directly from positive BCs have been developed. We evaluated an in-house method in comparison to the Sepsityper® Kit (Bruker Daltonics, Bremen, Germany) as well as the benefit of an on-plate formic acid extraction step following positive signal by the BACTECTM FX system. Confirmation of identification was achieved using subcultured growing biomass used for MALDI-TOF MS analysis. A total of 113 monomicrobial positive BCs were analyzed. The rates of Gram-positive bacteria correctly identified to the genus level using in-house method and Sepsityper® Kit were 63.3% (38/60) and 81.7% (49/60), respectively (p = 0.025). Identification rates at species level for Gram-positive bacteria with in-house method and Sepsityper® kit were 30.0% (18/60) and 66.7% (40/60), respectively (p < 0.001). Identification rates of Gram-negative bacteria were similar with the in-house method and Sepsityper® Kit. Additional on-plate formic acid extraction demonstrated significant improvement in the identification rate of Gram-positive bacteria at both genus and species level for both in-house (p = 0.001, p < 0.001) and Sepsityper® Kit methods (p = 0.007, p < 0.001). Our in-house method is a candidate for laboratory routines with Sepsityper® Kit as a back-up solution when identification of Gram-positive bacteria is unsuccessful.

Ceftolozane/tazobactam for the treatment of bacteremia: a systematic literature review (SLR)

Background

Bloodstream infections (BSIs), or bacteremia, are responsible for considerable disease burden. Increasing rates of antibiotic resistance and delays in selection of appropriate treatment lead to increased morbidity, mortality, and costs. Due to limitations of current standard treatments, especially for bacteremia caused by resistant pathogens, a systematic literature review (SLR) was conducted to understand the utilization of ceftolozane/tazobactam (C/T) in bacteremia.

Methods

Electronic database searches of EMBASE^®, MEDLINE^®, CCTR and Northern Lights, as well as hand searches of conference proceedings from the last two annual meetings (i.e., 2018, 2019) of the European Congress of Clinical Microbiological and Infectious Diseases (ECCMID) and the Infectious Diseases Society of America’s annual meeting (IDWeek) were conducted. A total of 23 studies reporting on patients with bacteremia receiving C/T were included in the review.

Results

Most studies were observational (k = 20 studies), though few interventional studies were also identified (k = 3). Heterogeneity was ubiquitous with respect to source of bacteremia (i.e., primary or secondary), source of infection (for secondary bacteremia), pathogen type, antibiotic resistance, C/T dose, and outcome definitions. This heterogeneity, along with limited data, and small sample sizes (n = 1 to 31) made it difficult to draw any substantial conclusions, though overall results were favorable to C/T with respect to the outcomes of interest. Nineteen studies reported clinical cure or success (primary bacteremia: k = 6, reported range: 33.3% to 100%; secondary bacteremia: k = 8, 60% to 100%; mixed/unspecified bacteremia: k = 10, 50% to 91.7%). Eight studies reported microbiological cure or eradication rates (primary: k = 3, all reporting 100%; secondary: k = 4, 68% to 80%; mixed/unspecified: k = 5, 60% to 80%). Thirteen studies reported mortality (primary: k = 4, 0% to 14%; secondary: k = 7, 0% to 100%; or mixed/unspecified bacteremia: k = 7, 0% to 51.6%). One study each also reported composite clinical response, relapse, hospital re-admission, and hospital length of stay.

Conclusions

Although the available evidence and observed trends for C/T in bacteremia should be interpreted with caution, the direction of effect would support the utilization of C/T for these difficult to treat infections. Future research should supplement the existing evidence by considering the impact of key treatment effect modifiers without contributing to the observed heterogeneity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-022-00528-0.

Burden of multidrug and extensively drug-resistant ESKAPEE pathogens in a secondary hospital care setting in Greece

Bacterial antibiotic resistance (AMR) is a significant threat to public health, with the sentinel 'ESKAPEE' pathogens, being of particular concern. A cohort study spanning 5.5 years (2016-2021) was conducted at a provincial general hospital in Crete, Greece, to describe the epidemiology of ESKAPEE-associated bacteraemia regarding levels of AMR and their impact on patient outcomes. In total, 239 bloodstream isolates were examined from 226 patients (0.7% of 32 996 admissions) with a median age of 75 years, 28% of whom had severe comorbidity and 46% with prior stay in ICU. Multidrug resistance (MDR) was lowest for Pseudomonas aeruginosa (30%) and Escherichia coli (33%), and highest among Acinetobacter baumannii (97%); the latter included 8 (22%) with extensive drug-resistance (XDR), half of which were resistant to all antibiotics tested. MDR bacteraemia was more likely to be healthcare-associated than community-onset (RR 1.67, 95% CI 1.04-2.65). Inpatient mortality was 22%, 35% and 63% for non-MDR, MDR and XDR episodes, respectively (P = 0.004). Competing risks survival analysis revealed increasing mortality linked to longer hospitalisation with increasing AMR levels, as well as differential pathogen-specific effects. A. baumannii bacteraemia was the most fatal (14-day death hazard ratio 3.39, 95% CI 1.74-6.63). Differences in microbiology, AMR profile and associated mortality compared to national and international data emphasise the importance of similar investigations of local epidemiology.

Pandemic clone USA300 in a Brazilian hospital: detection of an emergent lineage among methicillin-resistant Staphylococcus aureus isolates from bloodstream infections

Background

Staphylococcus aureus is one of the leading causes of bloodstream infections (BSI) worldwide. In Brazil, the hospital-acquired methicillin-resistant S. aureus USA100/SCCmecII lineage replaced the previously well-established clones. However, the emergence of community-associated (CA) MRSA lineages among hospitalized patients is an increasing issue.

Methods

Consecutive S. aureus isolates recovered from BSI episodes of patients admitted between January 2016 and December 2018 in a Brazilian teaching hospital were tested for antimicrobial resistance, their genotypic features were characterized, and the clinical characteristics of the patients were evaluated.

Results

A total of 123 S. aureus isolates were recovered from 113 patients. All isolates were susceptible to linezolid, teicoplanin and vancomycin and 13.8% were not susceptible to daptomycin. Vancomycin MIC50 and MIC90 of 2 mg/L were found for both MRSA and MSSA isolates. The MRSA isolation rate was 30.1% (37/123), and 51.4% of them carried the SCCmec type II, followed by SCCmecIV (40.5%). Among the 37 MRSA isolates, the main lineages found were USA100/SCCmecII/ST5 and ST105 (53.7%) and USA800/ST5/SCCmecIV (18.9%). Surprisingly, six (16%) CA-MRSA isolates, belonging to USA300/ST8/SCCmecIVa that carried PVL genes and the ACME cassette type I, were detected. These six patients with USA300 BSI had severe comorbidities, including cancer, and most had a Charlson score ≥ 5; furthermore, they were in wards attended by the same health professionals. MRSA isolates were associated with hospital acquired infections (p = 0.02) in more elderly patients (p = 0.03) and those diagnosed with hematologic cancer (p = 0.04). Among patients diagnosed with MRSA BSI, 19 (54.3%) died.

Conclusions

The pandemic MRSA USA300 was detected for the first time in the Brazilian teaching hospital under study, and its cross-transmission most probably occurred between patients with BSI. This lineage may already be circulating among other Brazilian hospitals, which highlights the importance of carrying out surveillance programs to fight multidrug resistant and hypervirulent isolates.

Activity of ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, cefiderocol and comparators against Gram-negative organisms causing bloodstream infections in Northern Italy (2019-2021): emergence of complex resistance phenotypes

Herein we assessed the frequency of Gram-negative organisms causing bloodstream infections and activity spectrum of ceftolozane-tazobactam (CTZ), ceftazidime-avibactam (CZA), meropenem-vaborbactam (MEV), cefiderocol (CFDC) and comparators. Overall, 1605 Gram-negative isolates were consecutively collected during 2019-2021. Enterobacterales represented more than 75% and exhibited >90% susceptibility to CZA (97%), amikacin (91.8%) and meropenem (90.6%). ESBL-producing Enterobacterales isolates showed high rates of susceptibility towards CZA (100%), carbapenems (89.1-100%) and CTZ (84.9-95.1%). MEV displayed the highest activity against KPC-producing Enterobacterales (MIC50/90, 0.75/4 mg/L; 92.9% susceptible) followed by CZA (MIC50/90, ≤2/>8 mg/L; 89.3% susceptible), CFDC (MIC50/90, 0.25/4 mg/L, 87.5% susceptible) and colistin (MIC50/90, ≤2/4 mg/L, 83.9% susceptible). High proportions of P. aeruginosa isolates were susceptible to colistin (97.8%), CZA (97.2%), CTZ (96.1%) and amikacin (94.5%). CFDC showed potent activity against Acinetobacter baumannii (MIC50/90, 0.5/1 mg/L; 97.2% susceptible), multi-drug resistant P. aeruginosa (MIC50/90, 0.25/1 mg/L; 96% susceptible), and Stenotrophomonas maltophilia (MIC50/90, 0.12/0.25 mg/L; 100% susceptible).

Validation of Three MicroScan® Antimicrobial Susceptibility Testing Plates Designed for Low-Resource Settings

Easy and robust antimicrobial susceptibility testing (AST) methods are essential in clinical bacteriology laboratories (CBL) in low-resource settings (LRS). We evaluated the Beckman Coulter MicroScan lyophilized broth microdilution panel designed to support Médecins Sans Frontières (MSF) CBL activity in difficult settings, in particular with the Mini-Lab. We evaluated the custom-designed MSF MicroScan Gram-pos microplate (MICPOS1) for Staphylococcus and Enterococcus species, MSF MicroScan Gram-neg microplate (MICNEG1) for Gram-negative bacilli, and MSF MicroScan Fastidious microplate (MICFAST1) for Streptococci and Haemophilus species using 387 isolates from routine CBLs from LRS against the reference methods. Results showed that, for all selected antibiotics on the three panels, the proportion of the category agreement was above 90% and the proportion of major and very major errors was below 3%, as per ISO standards. The use of the Prompt inoculation system was found to increase the MIC and the major error rate for some antibiotics when testing Staphylococci. The readability of the manufacturer’s user manual was considered challenging for low-skilled staff. The inoculations and readings of the panels were estimated as easy to use. In conclusion, the three MSF MicroScan MIC panels performed well against clinical isolates from LRS and provided a convenient, robust, and standardized AST method for use in CBL in LRS.

Staphylococcus aureus Causes the Arrest of Neutrophils in the Bloodstream in a Septicemia Model

Staphylococcus aureus induces the expression of VCAM-1, P- and E-selectins on the endothelial cells of the EA.hy926 cell line but, at the same time, causes the significant suppression of the force and work of adhesion between these receptors of endotheliocytes and the receptors of neutrophils in an experimental septicemia model. Adhesion contacts between the receptors of neutrophils and endotheliocytes are statistically significantly suppressed under non-opsonized and opsonized S. aureus treatment, which disrupts the initial stage of transendothelial migration of neutrophils—adhesion. Thus, S. aureus causes the arrest of neutrophils in the bloodstream in an experimental septicemia model.

Diagnostic Value and Prognostic Significance of Procalcitonin Combined with C-Reactive Protein in Patients with Bacterial Bloodstream Infection

Objective

To study the clinical values and implications for the prognosis of procalcitonin (PCT) combined with C-reactive protein (hs-CRP) in patients with bacterial bloodstream infection.

Methods

One hundred and twenty patients with infection hospitalized from Mar. 2020 to Jun. 2021 were chosen as subjects. All participants were tested for serum PCT, hs-CRP, and blood culture. According to the types of pathogenic bacteria, they were divided into the gram-negative bacteria bloodstream infection group (n = 53) and the gram-positive bacteria bloodstream infection group (n = 31). Depending on the prognostic outcome of the participants after 28 days, they were categorized into survival and fatality cohorts. The PCT and hs-CRP levels were compared to explore diagnostic value implications for the prognosis of the cases with bacterial bloodstream infection.

Results

Serum PCT and hs-CRP values in the positive cohort were higher than those in the negative cohort. The levels of serum PCT and hs-CRP in pulmonary infection were higher than those in the group with negative cases, and the difference was statistically significant (P < 0.05). There were 27 gram-positive participants and 9 gram-negative cases in the positive cohort. The serum PCT value of gram-negative bacterial infection was greater than that of gram-positive bacterial infection. The value of serum PCT in the gram-negative bacterial infection group was higher than that in the gram-positive bacterial infection group, and the difference was statistically significant (P < 0.05). The areas under the curve (AUCs) of PCT, combination of hs-CRP and PCT, and hs-CRP were 0.946, 0.783, and 0.991, respectively. The combined examination of PCT and hs-CRP was the largest, PCT was the second, and hs-CRP was the lowest. These results indicated that the accuracy of combined detection of PCT and hs-CRP in the diagnostic bloodstream infection was the highest (0.991), followed by PCT (0.946) and the lowest (0.783). The PCT and hs-CRP levels of the survival cohort were lower than those in the death cohort. AUCs of PCT, hs-CRP and PCT, and hs-CRP were 0.848, 0.826, and 0.934, respectively. The combined examination of PCT and hs-CRP was the largest, followed by PCT and hs-CRP. The accuracy of the combination of PCT and hs-CRP was the highest (0.934), followed by PCT (0.848), and the diagnostic accuracy of hs-CRP was the lowest (0.826).

Conclusion

There were significant differences in the levels of PCT and CRP between the gram-positive bacteria group and the gram-positive bacteria group. PCT and CRP have high diagnostic values in predicting the short-term prognosis of patients. PCT and CRP assist clinical diagnosis and guide treatment and play a positive role in early treatment and prognosis evaluation of patients.

Clinical validation of a multiplex droplet digital PCR for diagnosing suspected bloodstream infections in ICU practice: a promising diagnostic tool

Background

Droplet digital PCR (ddPCR) has emerged as a promising tool of pathogen detection in bloodstream infections (BSIs) in critical care medicine. However, different ddPCR platforms have variable sensitivity and specificity for diverse microorganisms at various infection sites. There is still a lack of prospective clinical studies aimed at validating and interpreting the discrepant ddPCR results for diagnosing BSI in intensive care unit (ICU) practice.

Methods

A prospective diagnostic study of multiplex ddPCR panels was conducted in a general ICU from May 21, 2021, to December 22, 2021. Paired blood cultures (BCs) and ddPCRs (2.5 h) were obtained synchronously to detect the 12 most common BSI pathogens and three antimicrobial resistance (AMR) genes. Firstly, ddPCR performance was compared to definite BSI. Secondly, clinical validation of ddPCR was compared to composite clinical diagnosis. Sensitivity, specificity, and positive and negative predictive values were calculated. Thirdly, the positive rate of AMR genes and related analysis was presented.

Results

A total of 438 episodes of suspected BSIs occurring in 150 critical patients were enrolled. BC and ddPCR were positive for targeted bacteria in 40 (9.1%) and 180 (41.1%) cases, respectively. There were 280 concordant and 158 discordant. In comparison with BCs, the sensitivity of ddPCR ranged from 58.8 to 86.7% with an aggregate of 72.5% in different species, with corresponding specificity ranging from 73.5 to 92.2% with an aggregate of 63.1%. Furthermore, the rate of ddPCR+/BC− results was 33.6% (147/438) with 87.1% (128 of 147) cases was associated with probable (n = 108) or possible (n = 20) BSIs. When clinically diagnosed BSI was used as true positive, the final sensitivity and specificity of ddPCR increased to 84.9% and 92.5%, respectively. In addition, 40 blaKPC, 3blaNDM, and 38 mecA genes were detected, among which 90.5% were definitely positive for blaKPC. Further, 65.8% specimens were predicted to be mecA-positive in Staphylococcus sp. according to all microbiological analysis.

Conclusions

The multiplexed ddPCR is a flexible and universal platform, which can be used as an add-on complementary to conventional BC. When combined with clinical infection evidence, ddPCR shows potential advantages for rapidly diagnosing suspected BSIs and AMR genes in ICU practice.

Evaluation of a diagnostic algorithm for rapid identification of Gram-negative species and detection of extended-spectrum β-lactamase and carbapenemase directly from blood cultures

Objectives

To evaluate a rapid diagnostic algorithm based on MALDI-TOF MS, lateral flow immunoassays (LFIAs) and molecular testing performed directly from positive blood cultures (BCs) for Gram-negative species identification and detection of CTX-M extended-spectrum β-lactamases and main carbapenemases.

Methods

Non-duplicate BCs positive to Gram-negative bacteria at microscope examination were subjected to species identification by direct MALDI-TOF MS following recovery of bacterial pellet by Rapid MBT Sepsityper® kit. Subsequently, NG-Test® CARBA 5 and NG-Test® CTX-M MULTI LFIAs were performed according to identified microbial species. Eazyplex® SuperBug CRE molecular assay was performed in cases of NG-Test® CARBA 5 negative results in patients with documented carbapenemase-producers carriage. Results of rapid diagnostic workflow were compared with those obtained by conventional diagnostic routine.

Results

Overall, the direct MALDI-TOF MS protocol allowed reliable identification to the species level of 92.1% of the 2133 monomicrobial BCs. Rate of matched identification was significantly higher for Enterobacterales (97.3%) in comparison to non-fermenting Gram-negative species (80.2%), obligate anaerobic bacteria (42.1%) and fastidious Gram-negative species (41.5%). The overall sensitivity of NG-Test® CARBA 5 and NG-Test® CTX-M MULTI was 92.2% and 91.6%, respectively. Integration of Easyplex® SuperBug CRE allowed the detection of blaKPC mutants associated with ceftazidime/avibactam resistance, reaching 100% sensitivity in carbapenemase detection. Both LFIAs and molecular testing showed no false-positive results.

Conclusions

Algorithms based on MALDI-TOF MS, LFIAs and molecular testing may represent a cost-effective tool to timely identify Gram-negative species and detect resistance markers directly from BCs. According to local epidemiology, these results may allow antimicrobial stewardship interventions including prompt use of new approved drugs.

Comparison of Clinical Outcomes for Glycopeptides and Beta-Lactams in Methicillin-Susceptible Staphylococcus Aureus Bloodstream Infections

PURPOSE

This study aimed to provide compelling evidence of anti-staphylococcal beta-lactam use for methicillin-susceptible Staphylococcus aureus bloodstream infection (MSSA BSI).

MATERIALS AND METHODS

We retrospectively collected data on patients with MSSA BSI who were admitted to two academic tertiary-care hospitals from 2010 to 2018. Only patients who received nafcillin, cefazolin, vancomycin, or teicoplanin as definitive therapy were included. The primary outcome was 28-day mortality. To perform unbiased comparisons between both treatments, we used inverse probability of treatment weighting (IPTW) analysis.

RESULTS

A total of 359 patients were divided into two groups based on the definitive therapy used: beta-lactams (n=203), including nafcillin or cefazolin; and glycopeptides (n=156), including vancomycin or teicoplanin. In the IPTW analysis, glycopeptides were associated with significantly increased odds of 28-day mortality (adjusted odds ratio, 3.37; 95% confidence interval, 1.71-6.61; p<0.001). The rate of primary outcome in prespecified subgroups was largely consistent with the main analysis.

CONCLUSION

Definitive therapy with beta-lactams in patients with MSSA BSI was associated with lower 28-day mortality compared to definitive therapy with glycopeptides.

Six-Year Time-Series Data on Multidrug-Resistant Bacteremia, Antibiotic Consumption, and Infection Control Interventions in a Hospital

Background: Multidrug-resistant (MDR) bacteremia is a serious health care-associated infection with significant morbidity and excess hospitalization costs. Our aim is to study the association between incidences of MDR bacteremia, antibiotic consumption, and infection control measures in a hospital from 2013 to 2018. Methods: We analyzed the following indices: (1) incidence of bacteremia (carbapenem-resistant Acinetobacter baumanii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococci); (2) use of antibiotics; (3) consumption of disinfectant solutions for hand hygiene; and (4) isolation rates of MDR carrier patients. Findings: The use of advanced antibiotics (p = 0.001) and carbapenems (p = 0.008) decreased significantly in all hospital departments but the incidence of total MDR bacteremia did not change significantly. Increased use of hand disinfectant solutions was statistically associated with decreased incidence of total MDR bacteremia (incidence rate ratio [IRR]: 0.94, confidence interval [95% CI]: 0.90-0.99, p: 0.020) in all hospital. Also, increased isolation rates of MDR carrier patients 2 months before correlated with decreased incidence of bacteremia due to carbapenem-resistant gram-negative pathogens (IRR: 0.35, 95% CI: 0.18-0.66, p: 0.001) in adults intensive care unit. Conclusion: In our hospital, hand hygiene and isolation of MDR carrier patients controlled MDR bacteremia.

A retrospective analysis of intravenous versus oral antibiotic step-down therapy for the treatment of uncomplicated Streptococcal bloodstream infections

Evidence supporting intravenous to oral (IV-to-PO) antibiotic de-escalation for uncomplicated Streptococcal bloodstream infections (BSIs) are limited. The objective of this study was to compare clinical outcomes of patients treated with IV-only versus IV-to-PO antibiotic therapy for uncomplicated Streptococcal BSIs. This was a single center, retrospective study of patients 18 years and older who received treatment for uncomplicated Streptococcal BSIs from January 2017 to December 2019. Patients were excluded if they had a polymicrobial BSI, endocarditis, osteomyelitis, septic arthritis, or received antibiotic therapy for longer than 14 days. The primary outcome was clinical failure, defined as persistent bacteremia, recurrence of bacteremia, or mortality at 30 days. Secondary outcomes included length of hospital stay, all-cause readmissions, development of C.difficile infection, and adverse antibiotic reactions. There were 98 patients who met the inclusion criteria; 51 patients in the IV-to-PO therapy group and 47 patients who received IV-only antibiotics. Streptococcus pneumonia and beta-hemolytic Streptococci were the most common pathogens. Patients received an average of 4.4 days of IV antibiotics before being stepped down to an oral agent. Hospital length of stay (6.3 vs. 12.6 days, p < 0.001) and total antibiotic duration of therapy (11.8 vs. 13.9 days, p = 0.002) were significantly shorter in patients receiving IV-to-PO therapy. There were no clinical failures observed in patients who received IV-to-PO antibiotic therapy. IV-to-oral step down therapy for uncomplicated Streptococcal BSIs was not associated with worse clinical outcomes compared to patients receiving IV-only antibiotic therapy. This article is protected by copyright. All rights reserved.

Recent Advances in Aptasensors For Rapid and Sensitive Detection of Staphylococcus Aureus

The infection of Staphylococcus aureus (S.aureus) and the spread of drug-resistant bacteria pose a serious threat to global public health. Therefore, timely, rapid and accurate detection of S. aureus is of great significance for food safety, environmental monitoring, clinical diagnosis and treatment, and prevention of drug-resistant bacteria dissemination. Traditional S. aureus detection methods such as culture identification, ELISA, PCR, MALDI-TOF-MS and sequencing, etc., have good sensitivity and specificity, but they are complex to operate, requiring professionals and expensive and complex machines. Therefore, it is still challenging to develop a fast, simple, low-cost, specific and sensitive S. aureus detection method. Recent studies have demonstrated that fast, specific, low-cost, low sample volume, automated, and portable aptasensors have been widely used for S. aureus detection and have been proposed as the most attractive alternatives to their traditional detection methods. In this review, recent advances of aptasensors based on different transducer (optical and electrochemical) for S. aureus detection have been discussed in details. Furthermore, the applications of aptasensors in point-of-care testing (POCT) have also been discussed. More and more aptasensors are combined with nanomaterials as efficient transducers and amplifiers, which appears to be the development trend in aptasensors. Finally, some significant challenges for the development and application of aptasensors are outlined.

Risk Factors and Outcome of Sepsis in Traumatic Patients and Pathogen Detection Using Metagenomic Next-Generation Sequencing

Objective

Sepsis, a life-threatening clinical syndrome, is a leading cause of mortality after experiencing multiple traumas. Once diagnosed with sepsis, patients should be given an appropriate empiric antimicrobial treatment followed by the specific antibiotic therapy based on blood culture due to its rapid progression to tissue damage and organ failure. In this study, we aimed to analyze the risk factors and outcome of sepsis in traumatic patients and to investigate the performance of metagenomic next-generation sequencing (mNGS) compared with standard microbiological diagnostics in post-traumatic sepsis.

Methods

The study included 528 patients with multiple traumas among which there were 142 cases with post-traumatic sepsis. Patients' demographic and clinical data were recorded. The outcome measures included mortality during the emergency intensive care unit (EICU), EICU length of stay (LOS), all-cause 28-day mortality, and total ventilator days in 28 days after admission. A total of 89 blood samples from 89 septic patients underwent standard microbiological blood cultures and 89 samples of peripheral blood (n = 21), wound secretion (n = 41), bronchoalveolar lavage fluid (BALF) (19), ascites (n = 5), and sputum (n = 3) underwent mNGS. Pathogen detection was compared between standard microbiological blood cultures and mNGS.

Results

The sepsis group and non-sepsis group exhibited significant differences regarding shock on admission, blood transfusion, mechanical ventilation, body temperature, heart rate, WBC count, neutrophil count, hematocrit, urea nitrogen, creatinine, CRP, D-D dimer, PCT, scores of APACHE II, sequential organ failure assessment (SOFA), and Injury Severity Score (ISS) on admission to the EICU, and Multiple Organ Dysfunction Syndromes (MODS) (P < 0.05). Multivariate logistic regression analysis showed that scores of APACHE II, SOFA, and ISS on admission, and MODS were independent risk factors for the occurrence of sepsis in patients with multiple traumas. The 28-day mortality was higher in the sepsis group than in the non-sepsis group (45.07% vs. 19.17%, P < 0.001). The mortality during the EICU was higher in the sepsis group than in the non-sepsis group (P=0.002). The LOS in the EICU in the sepsis group was increased compared with the non-sepsis group (P=0.004). The total ventilator days in 28 days after admission in the sepsis group was increased compared with the non-sepsis group (P < 0.001). Multivariate logistic regression analysis showed that septic shock, APACHE II score on admission, SOFA score, and MODS were independent risk factors of death for patients with post-traumatic sepsis. The positive detection rate of mNGS was 91.01% (81/89), which was significantly higher than that of standard microbiological blood cultures (39.33% (35/89)). Standard microbiological blood cultures and mNGS methods demonstrated double positive results in 33 (37.08%) specimens and double-negative results in 8 (8.99%) specimens, while 46 (51.69%) samples and 2 (2.25%) samples had positive results only with mNGS or culture alone, respectively.

Conclusion

Our study identifies risk factors for the incidence and death of sepsis in traumatic patients and shows that mNGS may serve as a better diagnostic tool for the identification of pathogens in post-traumatic sepsis than standard microbiological blood cultures.

Is shorter always better? The pros and cons of treating Gram-negative bloodstream infections with 7 days of antibiotics

Accumulating evidence from randomized controlled trials (RCTs) supports 7 days treatment for uncomplicated Gram-negative bacteraemia. However, some patient populations were not well represented in these RCTs, including critically ill patients, immunocompromised patients and those with MDR bacteria. In this debate document, we discuss the pros and cons for treating patients with Gram-negative bacteraemia with a 7 day antibiotic course. We surmise that the patients who were not well represented in the RCTs are probably those who have most to lose from the drawbacks of prolonged antibiotic courses, including adverse events, superinfections and resistance development. Treatment durations among these patients can be managed individually, with C-reactive protein or procalcitonin guidance or by clinical measures, and with care to discontinue antibiotics as soon as the patient recovers clinically from the infection.

Antimicrobial activity of dalbavancin against Gram-positive bacteria isolated from patients hospitalized with bloodstream infection in United States and European medical centers (2018-2020)

Dalbavancin and comparators were susceptibility tested against 8643 Gram-positive bacteria from 74 hospitals located in Europe and the United States by broth microdilution method. The most common organisms were Staphylococcus aureus (45.2%), Enterococcus faecalis (12.2%), and Staphylococcus epidermidis (8.9%), but rank order varied markedly by geographic region. Dalbavancin demonstrated potent activity and broad spectrum, with MIC₉₀ values of 0.03 mg/L for Staphylococcus aureus, β-haemolytic streptococci, and viridans group streptococci; 0.06 mg/L for Enterococcus faecalis and Staphylococcus epidermidis; and 0.12 mg/L for vancomycin-susceptible Enterococcus faecium. All organisms, except vancomycin-resistant enterococci and 1 Staphylococcus haemolyticus isolate, were inhibited at ≤ 0.25 mg/L of dalbavancin.

Antimicrobial Susceptibility Trends Among Gram-Negative Bacilli Causing Bloodstream Infections: Results from the China Antimicrobial Resistance Surveillance Trial (CARST) Program, 2011-2020

Purpose

The antimicrobial resistance profiles of gram-negative bacilli causing bloodstream infections have changed over time, while comprehensive and real-time surveillance data are limited in China. This study aimed to review the antimicrobial susceptibility trends among main gram-negative bacilli isolated from blood specimens in China.

Methods

From 2011 to 2020, a total of 4352 non-duplicate isolates were collected from 21 tertiary hospitals in 18 provinces or cities across China. Antimicrobial susceptibility testing was conducted by the agar dilution method recommended by the Clinical and Laboratory Standards Institute (CLSI), and the results were interpreted using CLSI criteria.

Results

During this 10-year surveillance period, meropenem and imipenem were the most effective agents against Escherichia coli (resistance remaining <5%). The proportion of ESBL-producing isolates in carbapenem-susceptible E. coli displayed a decreasing trend (from 72.9% to 51.2%). The resistance rates of Klebsiella pneumoniae to meropenem and imipenem increased from 3.3% and 1.6% in the 2011-12 period to 15.0% and 15.4% in the 2019-20 period, respectively. Carbapenems and amikacin were the most active agents against Enterobacter cloacae. The resistance rates of Pseudomonas aeruginosa to meropenem and imipenem increased from 13.1% and 17.7% in the 2015-16 period to 24.5% and 21.0% in the 2019-20 period, respectively. Few agents showed activity against Acinetobacter baumannii. The frequency of imipenem-non-susceptible A. baumannii remained stable (remaining ~70%).

Conclusion

The rapid spread of carbapenem-resistant K. pneumoniae has been serious in recent years. Conversely, the prevalence of ESBL-producing isolates was decreased. Carbapenems are still effective against gram-negative bacilli causing BSIs, except for A. baumannii. More attention should be given to A. baumannii, considering its high resistance against different classes of antimicrobials.

Direct Identification, Antimicrobial Susceptibility Testing, and Extended-Spectrum β-Lactamase and Carbapenemase Detection in Gram-Negative Bacteria Isolated from Blood Cultures

Purpose

To shorten the turnaround time for blood culture (BC) analyses, a rapid method was developed for the direct identification, antimicrobial susceptibility testing (AST), and multidrug resistance testing of bacteria-positive BCs.

Materials and Methods

The mixtures in BC bottles were treated with the multistep centrifugation method developed here and the conventional culture-based method. The bacterial sediment obtained after centrifugation was analyzed directly with MALDI-TOF MS and Vitek 2 Compact, and AST was performed directly with the Kirby–Bauer (K–B) disk diffusion, VITEK 2 Compact, and E-test methods. Extended spectrum lactamases (ESBLs) were detected with discs containing cefotaxime, cefotaxime/clavulanate, ceftazidime, and ceftazidime/clavulanate, and carbapenemase was detected with the modified carbapenem inactivation method (mCIM) and EDTA-mCIM (eCIM).

Results

All the results of direct testing were compared to those of the conventional methods, to evaluate the accuracy of the direct methods. The accuracies of the direct Vitek 2 Compact and MALDI-TOF MS methods were 95.5% (214/224) and 90.2% (202/224), respectively. Direct AST with K–B, Vitek 2, and E-test showed category agreement of 96.0% (2611/2721), 96.1% (2614/2721), and 97.4% (2650/2721), respectively, and the major errors and very major errors were < 2% for all three methods. In the direct determination of ESBLs, the results for cefotaxime combined with cefotaxime/clavulanate were completely consistent with those after the standard isolation method. The carbapenemase detection rate with direct mCIM and eCIM was exactly the same as that with the standard method.

Conclusion

These direct procedures based on multistep centrifugation are not only highly accurate but are appropriate for clinical laboratory use because the turnaround time is shorter.

Diagnosis and Management of Bloodstream Infections With Rapid, Multiplexed Molecular Assays

Bloodstream infection is a major health concern, responsible for considerable morbidity and mortality across the globe. Prompt identification of the responsible pathogen in the early stages of the disease allows clinicians to implement appropriate antibiotic therapy in a timelier manner. Rapid treatment with the correct antibiotic not only improves the chances of patient survival, but also significantly reduces the length of hospital stay and associated healthcare costs. Although culture has been the gold standard and most common method for diagnosis of bloodstream pathogens, it is being enhanced or supplanted with more advanced methods, including molecular tests that can reduce the turnaround time from several days to a few hours. In this article, we describe two rapid, molecular bloodstream infection panels that identify the most common pathogens and associated genetic determinants of antibiotic resistance – the Luminex^® VERIGENE^® Gram-Positive Blood Culture Test and the VERIGENE^® Gram-Negative Blood Culture Test. We conducted a search on PubMed to retrieve articles describing the performance and impact of these tests in the clinical setting. From a total of 48 articles retrieved, we selected 15 for inclusion in this review based on the type and size of the study and so there would be minimum of three articles describing performance and three articles describing the impact post-implementation for each assay. Here we provide a comprehensive review of these publications illustrating the performance and clinical utility of these assays, demonstrating how genotypic tests can benefit diagnostic and antimicrobial stewardship efforts.

Value of CRP, PCT, and NLR in Prediction of Severity and Prognosis of Patients With Bloodstream Infections and Sepsis

Objective

To investigate the value of C-reactive protein (CRP), procalcitonin (PCT), and neutrophil to lymphocyte ratio (NLR) in assessing the severity of disease in patients with bloodstream infection and sepsis, and to analyze the relationship between the levels of three inflammatory factors and the prognosis of patients.

Methods

The clinical data of 146 patients with bloodstream infection and sepsis admitted to our intensive care unit (ICU) from October 2016 to May 2020 were retrospectively analyzed. The differences in the levels of inflammatory indicators such as CRP, PCT, and NLR within 24 h in patients with bloodstream infection sepsis with different conditions (critical group, non-critical group) and the correlation between these factors and the condition (acute physiology and chronic health evaluation II, APACHE II score) were analyzed. In addition, the prognosis of all patients within 28 days was counted, and the patients were divided into death and survival groups according to their mortality, and the risk factors affecting their death were analyzed by logistic regression, and the receiver operating characteristic (ROC) curve was used to analyze the value of the relevant indicators in assessing the prognosis of patients.

Results

The levels of NLR, CRP, PCT, total bilirubin (TBIL), glutamic oxaloacetic transaminase (AST), and serum creatinine (Scr) were significantly higher in the critically ill group than in the non-critically ill group, where correlation analysis revealed a positive correlation between CRP, PCT, and NLR and APACHE II scores (P < 0.05). Univariate logistic regression analysis revealed that CRP, PCT, NLR, and APACHE II scores were associated with patient prognosis (P < 0.05). Multi-factor logistic regression analysis found that PCT, NLR, and APACHE II scores were independent risk factors for patient mortality within 28 days (P < 0.05). ROC curve analysis found that PCT and NLR both had an AUC area > 0.7 in predicting patient death within 28 days (P < 0.05).

Conclusion

Inflammatory factors such as NLR, CRP, and PCT have important clinical applications in the assessment of the extent of disease and prognosis of patients with bloodstream infection and sepsis.

Pilot Testing of the "Turbidimeter", a Simple, Universal Reader Intended to Complement and Enhance Bacterial Growth Detection in Manual Blood Culture Systems in Low-Resource Settings

Bloodstream infections and antimicrobial resistance are an increasing problem in low-income countries. There is a clear need for adapted diagnostic tools. To address this need, we developed a simple, universal reader prototype that detects bacterial growth in blood culture bottles. Our "turbidimeter" evaluates bacterial growth, based on the turbidity of the broth and the color change of the colorimetric CO2 indicator in commercially available blood culture bottles. A total of 60 measurements were performed using 10 relevant microbial species, spiked in horse blood, to compare the turbidimeter's performance with that of an automatic reference system. The turbidimeter was able to detect growth in all but one of the spiked blood culture bottles. In the majority (7/10) of the species tested, time-to-detection of the turbidimeter was shown to be non-inferior to the reference automated time-to-detection. This was, however, only the case when both the turbidity and color change in the colorimetric CO2-indicator were used to evaluate growth. We could not demonstrate the non-inferiority of the turbidity measurement alone. Overall, the turbidimeter performed well, but we also identified some improvements that will be implemented in the next version of the prototype.

Treatment outcomes of secondary bacteraemia in patients treated with ceftaroline fosamil: pooled results from six phase III clinical trials

OBJECTIVES

This exploratory pooled analysis assessed the efficacy and safety of ceftaroline fosamil and comparators across six phase III clinical trials in adults with community-acquired pneumonia (CAP) or complicated skin and soft-tissue infection (cSSTI) and secondary bacteraemia.

METHODS

In each trial, FOCUS 1 and 2 (CAP), Asia CAP trial, CANVAS 1 and 2 (cSSTI) and COVERS (cSSTI), patients were randomised to ceftaroline fosamil [600 mg q12h by 1-h i.v. infusion, except in COVERS (600 mg q8h by 2-h i.v. infusion), adjusted for renal function] or comparator. Efficacy assessments included clinical and microbiological responses at test-of-cure visit [microbiological modified intent-to-treat (mMITT) population]. Safety outcomes were assessed.

RESULTS

The pooled mMITT population comprised 1976 patients, of whom 138 had baseline bacteraemia (ceftaroline fosamil, n = 72; comparator, n = 66). Predominant baseline blood pathogens were Staphylococcus aureus (n = 29), Streptococcus pneumoniae (n = 19) and other streptococci (n = 12). Clinical cure rates in bacteraemic patients were 55/72 (76.4%) and 51/66 (77.3%) for ceftaroline fosamil and comparators, respectively, and in non-bacteraemic patients were 822/966 (85.1%) and 717/872 (82.2%). Favourable microbiological response rates in bacteraemic patients were 56/72 (77.8%) for ceftaroline fosamil and 54/66 (81.8%) for comparators, and in non-bacteraemic patients were 825/966 (85.4%) and 719/872 (82.5%). Adverse events in bacteraemic patients were consistent with the known ceftaroline fosamil safety profile or the underlying indications.

CONCLUSION

These pooled clinical and microbiological efficacy data demonstrate generally favourable outcomes for ceftaroline fosamil in patients with CAP or cSSTI and secondary bacteraemia. [Trial Registration: NCT00621504, NCT00509106; NCT01371838; NCT00424190, NCT00423657; NCT01499277].

Rural Raccoons (Procyon lotor) Not Likely to Be a Major Driver of Antimicrobial Resistant Human Salmonella Cases in Southern Ontario, Canada: A One Health Epidemiological Assessment Using Whole-Genome Sequence Data

Non-typhoidal Salmonella infections represent a substantial burden of illness in humans, and the increasing prevalence of antimicrobial resistance among these infections is a growing concern. Using a combination of Salmonella isolate short-read whole-genome sequence data from select human cases, raccoons, livestock and environmental sources, and an epidemiological framework, our objective was to determine if there was evidence for potential transmission of Salmonella and associated antimicrobial resistance determinants between these different sources in the Grand River watershed in Ontario, Canada. Logistic regression models were used to assess the potential associations between source type and the presence of select resistance genes and plasmid incompatibility types. A total of 608 isolates were obtained from the following sources: humans (n = 58), raccoons (n = 92), livestock (n = 329), and environmental samples (n = 129). Resistance genes of public health importance, including blaCMY−2, were identified in humans, livestock, and environmental sources, but not in raccoons. Most resistance genes analyzed were significantly more likely to be identified in livestock and/or human isolates than in raccoon isolates. Based on a 3,002-loci core genome multi-locus sequence typing (cgMLST) scheme, human Salmonella isolates were often more similar to isolates from livestock and environmental sources, than with those from raccoons. Rare instances of serovars S. Heidelberg and S. Enteritidis in raccoons likely represent incidental infections and highlight possible acquisition and dissemination of predominantly poultry-associated Salmonella by raccoons within these ecosystems. Raccoon-predominant serovars were either not identified among human isolates (S. Agona, S. Thompson) or differed by more than 350 cgMLST loci (S. Newport). Collectively, our findings suggest that the rural population of raccoons on swine farms in the Grand River watershed are unlikely to be major contributors to antimicrobial resistant human Salmonella cases in this region.

Expanded validation of the effect and quality of a pathogen inactivation system based on riboflavin photochemistry on platelet bacterial contamination

Background

Bacterial contamination still poses serious challenges to blood safety. Platelets have the highest bacterial contamination risk of all blood components.

Methods

Twenty units of manual platelets were prepared from blood donated by our hospital, which were inoculated with Staphylococcus aureus and Escherichia coli suspensions. The riboflavin sodium phosphate solution was added into platelets, adjusted to a final concentration of 160 μmol/L. Platelets added into an illumination bag and placed in the inactivation system for riboflavin photochemistry at various doses. The inactivation effect of bacteria was evaluated on a Columbia blood agar plate by the plate counting method. Meanwhile, the blood routine, blood gas analysis, platelet aggregation test, and thromboelastogram of platelets before and after treatment were detected to evaluate the changes of platelet quality after treatment.

Results

the inactivation effect of S. aureus and E. coli at the inactivation dose (16.9 J/cm²) could reach more than 4 logs. After treatment at 16.9 J/cm², the blood routine results showed that the platelet count was significantly different (P<0.05), and the blood gas analysis showed that the oxygen partial pressure (pO₂) and lactic acid concentration (cLac) were also significantly different (P<0.05). After 16.9 J/cm² treatment, there was a significant difference between Arachidonic acid (AA) and Collagen (Cog) activator groups in the platelet aggregation experiment (P<0.05), but there was no significant difference in the main thrombelastogram (TEG) parameters (R value, K value, angle value, MA value) after treatment (P>0.05).

Conclusions

The inactivation effect of this set of blood component pathogen inactivation system on platelet bacterial contamination could be considered to meet actual clinical needs, with the inactivation treatment having little impact on platelet function.

Blood bacterial resistant investigation collaborative system (BRICS) report: a national surveillance in China from 2014 to 2019

BACKGROUND

In this first national bloodstream infection (BSI) surveillance program in China, we assessed the composition of pathogenic bacteria and the trends for antimicrobial susceptibility over a 6-year period in China.

METHODS

Blood bacterial isolates from patients at hospitals participating in the Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected from January 2014 to December 2019. Only the first isolate of a species per patient was eligible over the full study period. Antibiotic-susceptibility testing was conducted by agar-dilution or broth-dilution methods as recommended by the Clinical and Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.

RESULTS

During the study period, 27,899 bacterial strains were collected. Gram-positive organisms accounted for 29.5% (8244) of the species identified and Gram-negative organisms accounted for 70.5% (19,655). The most-commonly isolated organisms in blood cultures were Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, coagulase-negative Staphylococci, and Acinetobacter baumannii. The prevalence of multidrug-resistant organisms, such as E. coli, K. pneumoniae, A. baumannii was higher in tertiary hospitals, whereas extended-spectrum, β-lactamase-producing E. coli (ESBL-E. coli), carbapenem-resistant A. baumannii were more prevalent in economically-developing areas. The prevalence of methicillin-resistant S. aureus declined from 39.0% (73/187) in 2014 to 25.9% (230/889) in 2019 (p < 0.05). The prevalence of ESBL-E. coli dropped from 61.2% (412/673) to 51.0% (1878/3,683) over time (p < 0.05), and carbapenem-resistant E. coli remained low prevalence (< 2%; 145/9944; p = 0.397). In contrast, carbapenem-resistant K. pneumoniae increased markedly from 7.0% (16/229) in 2014 to 19.6% (325/1,655) in 2019 (p < 0.05).

CONCLUSION

E. coli and K. pneumoniae were the leading causes of BSI during the 6-year study period. The major resistant pathogens declined or remained stable, whereas carbapenem-resistant K. pneumoniae continued to increase, which poses a great therapeutic challenge for BSIs.

Human MAIT Cells Respond to Staphylococcus aureus with Enhanced Anti-Bacterial Activity

Mucosal-Associated Invariant T (MAIT) cells have been shown to play protective roles during infection with diverse pathogens through their propensity for rapid innate-like cytokine production and cytotoxicity. Among the potential applications for MAIT cells is to defend against Staphylococcus aureus, a pathogen of serious clinical significance. However, it is unknown how MAIT cell responses to S. aureus are elicited, nor has it been investigated whether MAIT cell cytotoxicity is mobilized against intracellular S. aureus. In this study, we investigate the capacity of human MAIT cells to respond directly to S. aureus. MAIT cells co-cultured with dendritic cells (DCs) infected with S. aureus rapidly upregulate CD69, express IFNγ and Granzyme B and degranulate. DC secretion of IL-12, but not IL-18, was implicated in this immune response, while TCR binding of MR1 is required to commence cytokine production. MAIT cell cytotoxicity resulted in apoptosis of S. aureus-infected cells, and reduced intracellular persistence of S. aureus. These findings implicate these unconventional T cells in important, rapid anti-S. aureus responses that may be of great relevance to the ongoing development of novel anti-S. aureus treatments.

Microbial Distribution and Antibiotic Susceptibility of Bloodstream Infections in Different Intensive Care Units

Background: Bloodstream infection (BSI) is an increasing public health concern worldwide, representing a serious infection with significant morbidity and mortality, especially in children and the elderly. The predominant microbial distribution and antibiotic susceptibility were investigated among BSIs in the different intensive care units (ICUs)—pediatric ICU (PICU), surgical ICU (SICU), cardiac ICU (CICU), respiratory ICU (RICU), and geriatric ICU (GICU)—in order to achieve more efficient and appropriate therapies for patients in various ICUs.

Methods: In this retrospective cross-sectional study, the blood specimens were collected from five different ICUs of Peking University First Hospital and comprehensive ICU of Miyun Teaching Hospital (Miyun ICU) before antimicrobial treatment from 2017 to 2020. Microorganism cultures of the blood samples were conducted, and positive cultures were tested for type of pathogens and drug susceptibility.

Results: The prevalence of BSIs was the highest in the Miyun ICU (10.85%), followed by the RICU (9.48%) and the PICU (8.36%). The total prevalence of Gram-positive bacterial strains (especially Staphylococcus spp. and Enterococcus spp.) in the PICU (44.55%), SICU (57.58%), CICU (55.00%), GICU (49.06%), and Miyun ICU (57.58%) was higher than that of Gram-negative bacteria. The major bacterial strain was Acinetobacter baumannii in the PICU (21.82%); Klebsiella pneumoniae in the SICU (12.88%), CICU (30.00%), and RICU (30.39%); Escherichia coli in the GICU (20.75%); and Staphylococcus epidermidis (18.18%) in the Miyun ICU. Staphylococcus hominis of BSIs remained highly susceptible (>70%) to gentamicin, linezolid, daptomycin, teicoplanin, vancomycin, tigecycline, and rifampicin in all the ICUs. Its antibiotic sensitivity to levofloxacin was moderate in the PICU and CICU, but mild (<30%) in the SICU, RICU, and GICU. K. pneumoniae was highly susceptible to doxycycline, minocycline, and tigecycline in all the ICUs except the RICU, and its antibiotic sensitivity to imipenem, meropenem, amikacin, ciprofloxacin, and levofloxacin was high/moderate in the PICU, CICU, GICU, and Miyun ICU, but mild in the SICU and RICU.

Conclusion: The current study demonstrated the distribution of prevalent microorganisms, and their antimicrobial susceptibility exhibited a high divergence among BSIs in different ICUs from a tertiary hospital and an outer suburban hospital in Beijing. Therefore, different antibiotic therapies for various wards and distinct age groups (especially between pediatric and elderly patients) should be considered to control the emergence and spread of highly antibiotic-resistant infections.

Surveillance of Multidrug-Resistant Bacterial Infections in Non-Adult Patients - Zhejiang Province, China, 2014-2019

Introduction

Antimicrobial resistance has become a major public health threat globally. The prevalence of multidrug-resistant (MDR) bacterial infections increased substantially among inpatients under 18 years of age in recent years. In Zhejiang Province, China, the trends of drug-resistance in non-adult patients from 2014 to 2019 were monitored, aiming to determine the variation patterns and epidemiological features of MDR strains.

Methods

Patient data were collected from the Annual Review of Hospital Infection Resistance Survey in Zhejiang Province, 2014–2019. Statistical analysis was performed to analyze the pattern of distribution of five key bacterial pathogens in different age groups, ward settings, and bloodstream infections.

Results

From 2014 to 2019, a total of 30,163 multidrug-resistant strains were identified among 212,252 clinical isolates. The prevalence of extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA) were 40.6%, 2.3%, 14.7%, 9.0%, and 27.4%, respectively. The prevalence of these key pathogens was lower than that reported in the national surveillance system (China Antimicrobial Resistance Surveillance System and Infectious Diseases Surveillance of Pediatrics). The prevalence of ESBL-E and CRE decreased since 2015 but that of CRPA and MRSA increased from 2014 to 2018.

Conclusions

Despite an overall decrease in the prevalence of drug-resistant bacteria in 2019, the rising prevalence of MRSA and CRPA still warrant much attention. Multidrug-resistant bacteria prevention and control strategies should be adjusted in a timely manner based on the surveillance results.

Drug susceptibility and molecular epidemiology of Escherichia coli in bloodstream infections in Shanxi, China

Objectives

We carried out a retrospective study to investigate the drug susceptibility and genetic relationship of clinical Escherichia coli isolates from patients with BSIs in Shanxi, China.

Methods

E. coli isolates causing BSIs were consecutively collected from June 2019 to March 2020. Antimicrobial susceptibility testing was performed by broth microdilution method. PCR was used to detect antimicrobial resistance genes coding for extended-spectrum β-lactamases (ESBLs), phylogenetic groups and seven housekeeping genes of E. coli.

Results

A total of 76 E. coli were collected. Antimicrobial susceptibility testing revealed that the top six E. coli resistant antibiotics were ampicillin (90.7%), ciprofloxacin (69.7%), cefazolin (65.7%), levofloxacin (63.1%), ceftriaxone and cefotaxime (56.5%). Among the 76 isolates, 43 produced ESBLs. Molecular analysis showed that CTX-M-14 was the most common ESBLs, followed by CTX-M-15 and CTX-M-55. Phylogenetic group D (42.2%) predominated, followed by group B2 (34.2%), group A (18.4%) and group B1 (5.2%). The most prevalent sequence types (STs) were ST131 (15/76), ST69 (12/76) and ST38 (6/76).

Conclusions

This study is the first to report the phenotypic and molecular characteristics of E. coli isolated from BSIs in Shanxi, China. Our results indicated a high prevalence of MDR in E. coli strains isolated from BSIs and a serious spread of ESBL genes in Shanxi, especially the epidemiological bla _CTX-M. Phylogenetic analysis indicated genetic diversity among E. coli BSIs isolates.

Variability in oral antibiotic step-down therapy in the management of Gram-negative bloodstream infections

There are important gaps in the literature regarding the role and timing of oral therapy for Gram-negative bloodstream infections (GN-BSIs). To better understand contemporary management practices involving oral step-down in GN-BSI, we conducted an international survey of infectious diseases (ID) specialists. We developed and disseminated an online survey to ID specialists to assess practice patterns involving oral step-down in GN-BSIs, including providers from six continents and 28 countries. χ² tests and generalised estimating equations were used to identify factors associated with oral step-down. In total, 277 ID specialists completed the survey (64% physicians, 31% pharmacists). Relative to a line source, oral step-down was more common in abdominal [OR = 1.96 (95% CI 1.48-2.61); P < 0.001], pneumonia [2.24 (1.67-2.99); P < 0.001], skin [7.26 (4.71-11.20); P < 0.001] and urinary [9.15 (5.73-14.60); P < 0.001] sources of GN-BSI. US providers were more likely to practice oral step-down than non-US providers (OR = 4.35, 95% CI 2.57-7.36; P < 0.001). Moreover, 40% of providers practice oral step-down for some, but not all, sources of GN-BSI. Among all providers, 23-53% (depending on GN-BSI source) recommend extended (≥5 days) intravenous (IV) therapy before oral step-down or ongoing IV therapy. Most respondents (76% of all providers; 80% of ID physicians) expressed interest in enrolling patients in a trial of full IV versus early oral step-down for GN-BSI. There is extensive heterogeneity in oral step-down practices for GN-BSI. The optimal role of oral step-down in managing GN-BSIs warrants further investigation.

Comparative genomic characterization of multidrug-resistant Citrobacter spp. strains in Fennec fox imported to China

BACKGROUND

To investigate the antimicrobial profiles and genomic characteristics of MDR-Citrobacter spp. strains isolated from Fennec fox imported from Sudan to China.

METHODS

Four Citrobacter spp. strains were isolated from stool samples. Individual fresh stool samples were collected and subsequently diluted in phosphate buffered saline as described previously. The diluted fecal samples were plated on MacConkey agar supplemented with 1 mg/l cefotaxime and incubated for 20 h at 37 °C. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) was used for identification. Antimicrobial susceptibility testing was performed using the broth microdilution method. Whole-genome sequencing was performed on an Illumina Novaseq-6000 platform. Acquired antimicrobial resistance genes and plasmid replicons were detected using ResFinder 4.1 and PlasmidFinder 1.3, respectively. Comparative genomic analysis of 277 Citrobacter genomes was also performed.

RESULTS

Isolate FF141 was identified as Citrobacter cronae while isolate FF371, isolate FF414, and isolate FF423 were identified as Citrobacter braakii. Of these, three C. braakii isolates were further confirmed to be extended-spectrum β-lactamases (ESBL)-producer. All isolates are all multidrug resistance (MDR) with resistance to multiple antimicrobials. Plasmid of pKPC-CAV1321 belong to incompatibility (Inc) group. Comparative genomics analysis of Citrobacter isolates generated a large core-genome. Genetic diversity was observed in our bacterial collection, which clustered into five main clades. Human, environmental and animal Citrobacter isolates were distributed into five clusters.

CONCLUSIONS

To our knowledge, this is the first investigation of MDR-Citrobacter from Fennec Fox. Our phenotypic and genomic data further underscore the threat of increased ESBL prevalence in wildlife and emphasize that increased effort should be committed to monitoring the potentially rapid dissemination of ESBL-producers with one health perspective.

Clinical characteristics and outcomes of neonates with polymicrobial ventilator-associated pneumonia in the intensive care unit

BACKGROUND

Ventilator associated pneumonia (VAP) caused by more than one microorganisms is not uncommon and may be potentially challenging, but the relevant data is scarce in ventilated neonates. We aimed to investigate the clinical characteristics and outcomes of polymicrobial VAP in the neonatal intensive care unit (NICU).

METHODS

All neonates with definite diagnosis of VAP from a tertiary level neonatal intensive care unit (NICU) in Taiwan between October 2017 and September 2020 were prospectively observed and enrolled for analyses. All clinical features, therapeutic interventions and outcomes were compared between the polymicrobial VAP and monomicrobial VAP episodes. Multivariate regression analyses were used to find the independent risk factors for treatment failure.

RESULTS

Among 236 episodes of neonatal VAP, 60 (25.4%) were caused by more than one microorganisms. Polymicrobial VAP episodes were more likely to be associated with multidrug-resistant pathogens (53.3% versus 34.7%, P = 0.014), more often occurred in later days of life and in neonates with prolonged intubation and underlying bronchopulmonary dysplasia. Otherwise most clinical characteristics of polymicrobial VAP were similar to those of monomicrobial VAP. The therapeutic responses and treatment outcomes were also comparable between these two groups, although modification of therapeutic antibiotics were significantly more common in polymicrobial VAP episodes than monomicrobial VAP episodes (63.3% versus 46.2%; P < 0.001). None of any specific pathogens was significantly associated with worse outcomes. Instead, it is the severity of illness, including presence of concurrent bacteremia, septic shock, and requirement of high-frequency oscillatory ventilator and underlying neurological sequelae that are independently associated with treatment failure.

CONCLUSIONS

Polymicrobial VAP accounted for 25.4% of all neonatal VAP in the NICU, and frequently occurred in neonates with prolonged intubation and underlying bronchopulmonary dysplasia. In our cohort, most clinical features, therapeutic responses and final outcomes of neonates with monomicrobial and polymicrobial VAP did not differ significantly.

Initial antimicrobial management of sepsis

Sepsis is a common consequence of infection, associated with a mortality rate > 25%. Although community-acquired sepsis is more common, hospital-acquired infection is more lethal. The most common site of infection is the lung, followed by abdominal infection, catheter-associated blood steam infection and urinary tract infection. Gram-negative sepsis is more common than gram-positive infection, but sepsis can also be due to fungal and viral pathogens. To reduce mortality, it is necessary to give immediate, empiric, broad-spectrum therapy to those with severe sepsis and/or shock, but this approach can drive antimicrobial overuse and resistance and should be accompanied by a commitment to de-escalation and antimicrobial stewardship. Biomarkers such a procalcitonin can provide decision support for antibiotic use, and may identify patients with a low likelihood of infection, and in some settings, can guide duration of antibiotic therapy. Sepsis can involve drug-resistant pathogens, and this often necessitates consideration of newer antimicrobial agents.

Direct Testing for KPC-Mediated Carbapenem Resistance from Blood Samples Using a T2 Magnetic Resonance Based Assay

Molecular-based carbapenem resistance testing in Gram-negative bacterial bloodstream infections (BSIs) is currently limited because of the reliance on positive blood culture (BC) samples. The T2Resistance™ panel may now allow the detection of carbapenemase- and other β-lactamase encoding genes directly from blood samples. We detected carbapenem resistance genes in 11 (84.6%) of 13 samples from patients with BC-documented BSIs (10 caused by KPC-producing Klebsiellapneumoniae and 1 caused by VIM/CMY-producing Citrobacter freundii). Two samples that tested negative for carbapenem resistance genes were from patients with BC-documented BSIs caused by KPC-producing K. pneumoniae who were receiving effective antibiotic therapy. In conclusion, our findings suggest that the T2Resistance™ panel can be a reliable tool for diagnosing carbapenem-resistant Gram-negative bacterial BSIs.

Penicillin susceptibility among invasive MSSA infections: a multicentre study in 16 Spanish hospitals

OBJECTIVES

To determine the prevalence of penicillin susceptibility among MSSA causing bloodstream infections (BSIs) in 16 Spanish hospitals and to characterize the penicillin-susceptible MSSA (MSSA-PENS) isolates.

METHODS

A total of 1011 Staphylococcus aureus isolates were collected from blood cultures in 16 Spanish hospitals during 2018-19 (6-12 months) and their susceptibility to 18 antimicrobials was determined. The MSSA-PENS isolates were selected and examined by PCR to determine the presence of the blaZ gene, other resistance genes and the genes lukF/lukS-PV, eta, etb and tst. The immune evasion cluster (IEC) type was also analysed. All the MSSA-PENS isolates were submitted to S. aureus protein A (spa) typing and the clonal complexes (CCs) were assigned according to their spa type.

RESULTS

The prevalence of MSSA was 74.6% (754/1011) and 14.9% (151/1011) were MSSA-PENS-blaZnegative. MSSA-PENS-blaZnegative isolates (n = 151) were ascribed to 88 spa types and 11 CCs. The most frequent CCs were CC5 (35/151) and CC398 (25/151), with t002-CC5 and t571-CC398 being the most common lineages. Pan-susceptibility was identified in 117 of the 151 MSSA-PENS-blaZnegative isolates (77.5%). In the remaining isolates, erythromycin and clindamycin resistance was the most frequent resistance found, although tobramycin, ciprofloxacin, fusidic acid, mupirocin and/or tetracycline resistance was also detected. Thirty-eight MSSA-PENS-blaZnegative isolates were IEC negative and four isolates were Panton-Valentine leucocidin ('PVL') positive.

CONCLUSIONS

A high penicillin susceptibility rate was detected among MSSA, opening therapeutic opportunities for BSIs. The emergence of new successful MSSA-PENS clones could be responsible for these data. The detection among MSSA-PENS-blaZnegative isolates of the clonal lineage CC398 or the absence of an IEC raises questions about their possible animal origin, requiring further analysis.

Emergence and dissemination of antimicrobial resistance in Escherichia coli causing bloodstream infections in Norway in 2002-17: a nationwide, longitudinal, microbial population genomic study

BACKGROUND

The clonal diversity underpinning trends in multidrug resistant Escherichia coli causing bloodstream infections remains uncertain. We aimed to determine the contribution of individual clones to resistance over time, using large-scale genomics-based molecular epidemiology.

METHODS

This was a longitudinal, E coli population, genomic, cohort study that sampled isolates from 22 512 E coli bloodstream infections included in the Norwegian surveillance programme on resistant microbes (NORM) from 2002 to 2017. 15 of 22 laboratories were able to share their isolates, and the first 22·5% of isolates from each year were requested. We used whole genome sequencing to infer the population structure (PopPUNK), and we investigated the clade composition of the dominant multidrug resistant clonal complex (CC)131 using genetic markers previously reported for sequence type (ST)131, effective population size (BEAST), and presence of determinants of antimicrobial resistance (ARIBA, PointFinder, and ResFinder databases) over time. We compared these features between the 2002-10 and 2011-17 time periods. We also compared our results with those of a longitudinal study from the UK done between 2001 and 2011.

FINDINGS

Of the 3500 isolates requested from the participating laboratories, 3397 (97·1%) were received, of which 3254 (95·8%) were successfully sequenced and included in the analysis. A significant increase in the number of multidrug resistant CC131 isolates from 71 (5·6%) of 1277 in 2002-10 to 207 (10·5%) of 1977 in 2011-17 (p<0·0001), was the largest clonal expansion. CC131 was the most common clone in extended-spectrum β-lactamase (ESBL)-positive isolates (75 [58·6%] of 128) and fluoroquinolone non-susceptible isolates (148 [39·2%] of 378). Within CC131, clade A increased in prevalence from 2002, whereas the global multidrug resistant clade C2 was not observed until 2007. Multiple de-novo acquisitions of both blaCTX-M ESBL-encoding genes in clades A and C1 and gain of phenotypic fluoroquinolone non-susceptibility across the clade A phylogeny were observed. We estimated that exponential increases in the effective population sizes of clades A, C1, and C2 occurred in the mid-2000s, and in clade B a decade earlier. The rate of increase in the estimated effective population size of clade A (Ne=3147) was nearly ten-times that of C2 (Ne=345), with clade A over-represented in Norwegian CC131 isolates (75 [27·0%] of 278) compared with the UK study (8 [5·4%] of 147 isolates).

INTERPRETATION

The early and sustained establishment of predominantly antimicrobial susceptible CC131 clade A isolates, relative to multidrug resistant clade C2 isolates, suggests that resistance is not necessary for clonal success. However, even in the low antibiotic use setting of Norway, resistance to important antimicrobial classes has rapidly been selected for in CC131 clade A isolates. This study shows the importance of genomic surveillance in uncovering the complex ecology underlying multidrug resistance dissemination and competition, which have implications for the design of strategies and interventions to control the spread of high-risk multidrug resistant clones.

FUNDING

Trond Mohn Foundation, European Research Council, Marie Skłodowska-Curie Actions, and the Wellcome Trust.

Molecular Characteristics of Escherichia coli Causing Bloodstream Infections During 2010-2015 in a Tertiary Hospital, Shanghai, China

BACKGROUND

The bloodstream infections (BSI) caused by Escherichia coli pose a serious threat to human health. To explore molecular characteristics of E. coli causing BSI, we collected E. coli isolates causing BSI in Huashan Hospital, Shanghai, China during 2010-2015.

METHODS

In all E. coli isolates causing BSI collected from this study, polymerase chain reaction (PCR) was used to detect ESBLs and carbapenemase genes, and minimum inhibitory concentrations (MICs) were determined with agar dilution method. Outer membrane proteins were examined by SDS-PAGE in carbapenem-resistant strains. The genetic background of bla KPC gene was investigated by combining next-generation sequencing with a PCR mapping approach. Conjugation and transformation experiments were performed to verify the mobilization of bla KPC. The transcription levels of the bla KPC gene were measured by RT-PCR.

RESULTS

During 2010-2015, a total of 207 E. coli BSI strains were isolated. The positive rates of β-lactamase resistant genes were 0.48% (bla KPC), 57% (bla TEM), 23.67% (bla CTX-M-1), 18.84% (bla CTX-M-9), and 1.93% (bla SHV). High rates of bla TEM, bla CTX-M-1, and bla CTX-M-9 were consistent with the poor activity of third-generation cephalosporins and aztreonam in vitro, except for carbapenem and β-lactamase inhibitor combinations. Low susceptibility rates were observed for piperacillin (25.1%) in contrast to the increased susceptibility when combined with β-lactamase inhibitors, namely piperacillin-tazobactam (90.8%). Only one KPC-producing E. coli strain was detected. Despite the combination of OmpC loss, the low expression level of KPC may be responsible for its lower resistance to carbapenems compared to E. coli DH5α (pKP12-100).

CONCLUSION

E. coli strains isolated from BSI were still highly susceptible to carbapenems and β-lactamase inhibitor combinations, and bla CTX-M was the dominant genotype of ESBLs. The low expression of bla KPC may be the reason for the low resistance to carbapenems.

Decrease in All-Cause 30-Day Mortality after Bacteraemia over a 15-Year Period: A Population-Based Cohort Study in Denmark in 2000-2014

INTRODUCTION

Bacteraemia is a frequent infectious condition that strongly affects morbidity and mortality. The incidence is increasing worldwide. This study explores all-cause 30-day mortality after bacteraemia in two out of Denmark's five healthcare regions with approximately 2.4 million inhabitants.

METHODS

Clinically significant bacteraemia episodes (n = 55,257) were identified from a geographically well-defined background population between 2000 and 2014, drawing on population-based data regarding bacterial species and vital status. All-cause 30-day mortality was assessed in relation to bacteraemia episodes, number of patients with analysed blood cultures and the background population.

RESULTS

We observed a decreasing trend of all-cause 30-day mortality between 2000 and 2014, both in relation to the number of bacteraemia episodes and the background population. Mortality decreased from 22.7% of the bacteraemia episodes in 2000 to 17.4% in 2014 (annual IRR [95% CI]: 0.983 [0.979-0.987]). In relation to the background population, there were 41 deaths per 100,000 inhabitants in 2000, decreasing to 39 in 2014 (annual IRR [95% CI]: 0.988 [0.982-0.993]). Numbers of inhabitants, bacteraemia episodes, and analysed persons having BCs increased during the period.

CONCLUSIONS

All-cause 30-day mortality in patients with bacteraemia decreased significantly over a 15-year period.