Rapid Direct Identification of Microbial Pathogens and Antimicrobial Resistance Genes in Positive Blood Cultures Using a Fully Automated Multiplex PCR Assay

This study assessed the performance of the BioFire Blood Culture Identification 2 (BCID2) panel in identifying microorganisms and antimicrobial resistance (AMR) profiles in positive blood cultures (BCs) and its influence on turnaround time (TAT) compared with conventional culture methods. We obtained 117 positive BCs, of these, 102 (87.2%) were correctly identified using BCID2. The discordance was due to off-panel pathogens detected by culture (n = 13), and additional pathogens identified by BCID2 (n = 2). On-panel pathogen concordance between the conventional culture and BCID2 methods was 98.1% (102/104). The conventional method detected 19 carbapenemase-producing organisms, 14 extended-spectrum beta-lactamase-producing Enterobacterales, 18 methicillin-resistant Staphylococcus spp., and four vancomycin-resistant Enterococcus faecium. BCID2 correctly predicted 53 (96.4%) of 55 phenotypic resistance patterns by detecting AMR genes. The TAT for BCID2 was significantly lower than that for the conventional method. BCID2 rapidly identifies pathogens and AMR genes in positive BCs.

Rapid diagnostic tests and antimicrobial stewardship programs for the management of bloodstream infection: What is their relative contribution to improving clinical outcomes? A systematic review and network meta-analysis

BACKGROUND

Evidence about the clinical impact of rapid diagnostic tests (RDT) for the diagnosis of bloodstream infections is limited, and whether RDT are superior to conventional blood cultures (BC) embedded within antimicrobial stewardship programs (ASP) is unknown.

METHODS

We performed network meta-analyses (NMA) using results from studies of patients with bloodstream infection with the aim of comparing the clinical impact of RDT (applied on positive BC broth or whole blood) to conventional BC, both assessed with and without ASP with respect to mortality, length of stay (LOS) and time to optimal therapy (TOT).

RESULTS

Eighty-eight papers were selected, including 25,682 patient encounters. There was an appreciable amount of statistical heterogeneity within each meta-analysis. The NMA showed a significant reduction in mortality associated with the use of RDT + ASP vs BC alone (OR 0.72, 95%CI 0.59, 0.87) and with the use of RDT + ASP vs BC + ASP (OR 0.78 95%CI 0.63, 0.96). No benefit in survival was found associated with the use of RDT alone nor with BC + ASP compared to BC alone. A reduction in LOS was associated with RDT + ASP vs BC alone (0.91, 95%CI 0.84, 0.98) while no difference in LOS was shown between any other groups. A reduced TOT was shown when RDT + ASP was compared to BC alone (-29 h, 95%CI -35, -23), BC + ASP (-18 h, 95%CI -27, -10) and to RDT alone (-12 h, 95%CI -20, -3).

CONCLUSION

The use of RDT + ASP may lead to a survival benefit even when introduced in settings already adopting effective ASP in association with conventional BC.

Recurrent Infective Endocarditis in an Adolescent due to Streptococcus agalactiae: A Rare Presentation of a Common Pathogen

Streptococcus agalactiae is known to cause invasive infections in risk groups such as pregnant women, newborns, and immunosuppressed patients but it is uncommon in older children. We describe a case of recurrent infective endocarditis due to S. agalactiae in an 11-year-old boy with Loeys-Dietz syndrome who was successfully treated with long-term antimicrobial therapy for one year.

Effect of Wearing Personal Protective Equipment (PPE) for COVID-19 Treatment on Blood Culture Contamination: Implication for Optimal PPE Strategies

The personal protective equipment (PPE) used to minimize exposure to hazards can hinder healthcare workers from performing sophisticated procedures. We retrospectively reviewed 77,535 blood cultures (202,012 pairs) performed in 28,502 patients from January 2020 to April 2022. The contamination rate of all blood cultures was significantly elevated in the coronavirus disease 2019 ward at 4.68%, compared to intensive care units at 2.56%, emergency rooms at 1.13%, hematology wards at 1.08%, and general wards at 1.07% (All of P < 0.001). This finding implies that wearing PPE might interfere with adherence to the aseptic technique. Therefore, a new PPE policy is needed that considers the balance between protecting healthcare workers and medical practices.

No more tears from surgical site infections in interventional pain management

As the field of interventional pain management (IPM) grows, the risk of surgical site infections (SSIs) is increasing. SSI is defined as an infection of the incision or organ/space that occurs within one month after operation or three months after implantation. It is also common to find patients with suspected infection in an outpatient clinic. The most frequent IPM procedures are performed in the spine. Even though primary pyogenic spondylodiscitis via hematogenous spread is the most common type among spinal infections, secondary spinal infections from direct inoculation should be monitored after IPM procedures. Various preventive guidelines for SSI have been published. Cefazolin, followed by vancomycin, is the most commonly used surgical antibiotic prophylaxis in IPM. Diagnosis of SSI is confirmed by purulent discharge, isolation of causative organisms, pain/tenderness, swelling, redness, or heat, or diagnosis by a surgeon or attending physician. Inflammatory markers include traditional (C-reactive protein, erythrocyte sedimentation rate, and white blood cell count) and novel (procalcitonin, serum amyloid A, and presepsin) markers. Empirical antibiotic therapy is defined as the initial administration of antibiotics within at least 24 hours prior to the results of blood culture and antibiotic susceptibility testing. Definitive antibiotic therapy is initiated based on the above culture and testing. Combination antibiotic therapy for multidrug-resistant Gram-negative bacteria infections appears to be superior to monotherapy in mortality with the risk of increasing antibiotic resistance rates. The never-ending war between bacterial resistance and new antibiotics is continuing. This article reviews prevention, diagnosis, and treatment of infection in pain medicine.

Clinical, Microbiological, and Imaging Characteristics of Infective Endocarditis in Latin America: A Systematic Review

OBJECTIVES

We aimed to describe the clinical, microbiological, and imaging characteristics of patients with infective endocarditis (IE) in studies from Latin America (LATAM).

METHODS

A systematic search through PubMed, EMBASE, LILACS, and SciELO from inception until February 2021 was conducted. We included observational studies that assessed adults with IE from LATAM and reported data on clinical, microbiological, or imaging characteristics. Data were independently extracted by 2 authors and the risk of bias was evaluated by study design with its respective tool. Findings were summarized using descriptive statistics.

RESULTS

Forty-four studies were included. Most cases were male (68.5%), had a predisposing condition including valve disease (24.3%), or had a prosthetic valve (23.4%). Clinical manifestations included fever (83.9%), malaise (63.2%), or heart murmur (57.7%). A total of 36.4% and 27.1% developed heart failure or embolism, respectively. Blood cultures were negative in 23.9% and S. aureus (18.6%) and the viridans group streptococci (17.8%) were the most common isolates. Most cases were native valve IE (67.3%) affecting mainly left-sided valves. Echocardiographic findings included vegetations (84.3%) and regurgitation (75.9%). In-hospital mortality was 25.1%.

CONCLUSIONS

This is the first systematic review that evaluated the characteristics of IE in LATAM patients. A lack of multicenter studies reflects the need for these studies in LATAM.

Major Adverse Kidney Events in Pediatric Sepsis

BACKGROUND AND OBJECTIVES

Major adverse kidney events, a composite of death, new kidney replacement therapy, or persistent kidney dysfunction, is a potential patient-centered outcome for clinical trials in sepsis-associated kidney injury. We sought to determine the incidence of major adverse kidney events within 30 days and validate this end point in pediatric sepsis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective observational study using the Pediatric Health Information Systems Plus database of patients >6 months to <18 years old with a diagnosis of severe sepsis/septic shock; orders for bacterial blood culture, antibiotics, and at least one fluid bolus on hospital day 0/1; and known hospital disposition between January 2007 and December 2011. The primary outcome was incidence of major adverse kidney events within 30 days. Major adverse kidney events within 30 days were validated against all-cause mortality at hospital discharge, hospital length of stay, total hospital costs, hospital readmission within 30 days and 1 year, and lowest eGFR between 3 months and 1 year after discharge. We reported incidence of major adverse kidney events within 30 days with 95% confidence intervals using robust SEM and used multivariable logistic regression to test the association of major adverse kidney events within 30 days with hospital costs and mortality.

RESULTS

Of 1685 admissions, incidence of major adverse kidney events within 30 days was 9.6% (95% confidence interval, 8.1% to 11.0%), including 4.5% (95% confidence interval, 3.5% to 5.4%) death, 1.7% (95% confidence interval, 1.1% to 2.3%) kidney replacement therapy, and 5.8% (95% confidence interval, 4.7% to 6.9%) persistent kidney dysfunction. Patients with versus without major adverse kidney events within 30 days had higher all-cause mortality at hospital discharge (28% versus 1%; P<0.001), higher total hospital costs ($61,188; interquartile range, $21,272-140,356 versus $28,107; interquartile range, $13,056-72,697; P<0.001), and higher proportion with eGFR<60 ml/min per 1.73 m² between 3 months and 1 year after discharge (19% versus 4%; P=0.001). Major adverse kidney events within 30 days was not associated with length of stay or readmissions.

CONCLUSIONS

In children with sepsis, major adverse kidney events within 30 days are common, feasible to measure, and a promising end point for future clinical trials.

Recommended Clinical Trial End Points for Dialysis Catheters

Central venous catheters are used frequently in patients on hemodialysis as a bridge to a permanent vascular access. They are prone to frequent complications, including catheter-related bloodstream infection, catheter dysfunction, and central vein obstruction. There is a compelling need to develop new drugs or devices to prevent central venous catheter complications. We convened a multidisciplinary panel of experts to propose standardized definitions of catheter end points to guide the design of future clinical trials seeking approval from the Food and Drug Administration. Our workgroup suggests diagnosing catheter-related bloodstream infection in catheter-dependent patients on hemodialysis with a clinical suspicion of infection (fever, rigors, altered mental status, or unexplained hypotension), blood cultures growing the same organism from the catheter hub and a peripheral vein (or the dialysis bloodline), and absence of evidence for an alternative source of infection. Catheter dysfunction is defined as the inability of a central venous catheter to (1) complete a single dialysis session without triggering recurrent pressure alarms or (2) reproducibly deliver a mean dialysis blood flow of >300 ml/min (with arterial and venous pressures being within the hemodialysis unit parameters) on two consecutive dialysis sessions or provide a Kt/V≥1.2 in 4 hours or less. Catheter dysfunction is defined only if it persists, despite attempts to reposition the patient, reverse the arterial and venous lines, or forcefully flush the catheter. Central vein obstruction is suspected in patients with >70% stenosis of a central vein by contrast venography or the equivalent, ipsilateral upper extremity edema, and an existing or prior history of a central venous catheter. There is some uncertainty about the specific criteria for these diagnoses, and the workgroup has also proposed future high-priority studies to resolve these questions.

Evaluation of PCR-reverse blot hybridization assay, REBA Sepsis-ID test, for simultaneous identification of bacterial pathogens and mecA and van genes from blood culture bottles

Background

The aim of this study was to evaluate a newly developed PCR-based reverse blot hybridization assay (PCR-REBA), REBA Sepsis-ID (M&D, Wonju, Korea), to rapidly detect the presence of bacteremia and antimicrobial resistance gene in blood culture samples.

Methods

One thousand four hundred consecutive blood culture samples from patients with a delta neutrophil index greater than 2.7% were selected from March to July in 2013. Three hundred positive and 1,100 negative for bacterial growth in blood culture bottles samples were tested by conventional and real-time PCR-REBA, respectively.

Results

The overall agreement between the conventional identification test and the REBA Sepsis-ID test was 95.3% (286/300). Agreement for gram-positive bacteria, gram-negative bacteria, fungi, and polymicrobials was 94.5% (190/201), 97.3% (71/73), 100% (14/14), and 91.7% (11/12), respectively. The detection rate of the mecA gene from methicillin-resistant Staphylococcus isolates was 97.8% (90/92). The vanA gene was detected in one blood culture sample from which vancomycin-resistant Enterococcus was isolated. When the cycle threshold for real-time PCR was defined as 30.0, 2.4% (26/1,100) of negative blood culture samples tested positive by real-time PCR.

Conclusions

The REBA Sepsis-ID test is capable of simultaneously and quickly detecting both causative agents and antimicrobial resistance genes, such as mecA and van, in blood culture positive samples.

Can serum procalcitonin and C-reactive protein as nosocomial infection markers in hospitalized patients without localizing signs?

BACKGROUND

Early diagnosis of infection with the use of valuable markers leads to decreased mortality and morbidity. The aim of this study was to evaluate the value of procalcitonin (PCT) and C-reactive protein (CRP) for detecting nosocomial infection in hospitalized patients without localizing signs.

METHODS

We conducted a prospective observational study on 150 hospitalized patients with fever > 38°C emerging 48-72 hours after their admission at Alzahra Hospital, Isfahan, Iran. The subjects did not have any localizing sign of infection. PCT and CRP values were determined using rapid tests and were compared with results of blood culture as the standard test. The sensitivity, specificity, positive and negative predictive values (PV) and likelihood ratios (LRs) were calculated for both PCT and CRP. Receiver operating characteristic (ROC) curves were also used to evaluate the diagnostic value of the PCT and CRP for detecting nosocomial infections. Finally, the areas under the resulting curves were compared.

RESULTS

PCT had a sensitivity of 57.1%, a specificity of 89.1%, a positive PV of 46.2%, and a negative PV of 92.7% while the corresponding percentages for CRP test were 76.2%, 48%, 19.3%, and 92.5%. PCT marker also had a higher positive LR and lower negative LR than did CRP marker. The observed areas under the ROC curves were 0.73 for CRP (95% CI, 0.63-0.82; p = 0.023) and 0.80 for PCT (95% CI, 0.68-0.91; p = 0.001). The optimal cut-off values (best diagnostic accuracy) were 39 mg/L for CRP and 7.5 ng/mL for PCT.

CONCLUSIONS

Determination of PCT and CRP is a valuable tool for identifying nosocomial infections. PCT showed better specificity, negative and positive PV. However CRP showed significantly better sensitivity compared with PCT. Therefore, these tests should be considered as part of initial work-up for patients with unknown source of infection.