Blood culture contamination: persisting problems and partial progress

Safety of Intraoperative Cell Salvage in Two-Stage Revision of Septic Hip Arthroplasties

(1) Background: The aim of this study was to evaluate the safety of intraoperative cell salvage (ICS) during reimplantation in the two-stage revision of septic hip arthroplasties. (2) Methods: As part of an internal quality control study, blood cultures were taken from the processed ICS blood during reimplantation and examined for possible bacterial load (study group). Due to a high rate of bacterial detection with uncertain clinical significance, consecutive ICS samples were also examined from patients undergoing aseptic revision hip arthroplasty (control group). Microbiological samples, patient and surgical characteristics and the follow-up data were analyzed retrospectively. (3) Results: 9 out of 12 (75%) patients in the study group and 5 out of 8 (63%) patients in the control group had positive ICS blood cultures. There was no significant difference between the groups (p = 0.642). The initial pathogens causing the periprosthetic joint infection (PJI) were not detected, but the bacterial spectrum resembled skin flora, with a high proportion of coagulase-negative staphylococci. No complications due to possible bloodstream-associated infections were observed. In summary, the detected pathogens were interpreted as contamination without clinical significance. (4) Conclusions: ICS in the context of reimplantation was considered a safe and recommendable procedure to optimize patient blood management.

Reducing Blood Culture Contamination Rates: Introduction of a Combined Education and Skin Antisepsis Intervention

Background. Blood culture contamination (BCC) is an important quality concern in clinical microbiology as it can lead to unnecessary antimicrobial therapy in patients and increased workload for laboratory scientists. The Clinical Laboratory and Standards Institute recommend BCC rates to be <3 % and recently updated guidelines have set a new goal of 1 %. The aim of this project was to design and implement interventions to reduce BCC rates at our institution. Methods. We introduced a combined education and skin antisepsis intervention in a large Model 4 academic teaching hospital in the South of Ireland. BD ChloraPrep skin antisepsis applicators (2 % chlorhexidine gluconate/70 % isopropyl alcohol), licensed for use for blood culture specimen collection, were introduced, replacing Clinell (2 % chlorhexidine gluconate/70 % isopropyl alcohol) wipes. In addition, a multimodal education programme was designed and delivered. This consisted of a video demonstrating the recommended blood culture specimen collection technique using the new applicators as well as simulation training for all interns. The video was uploaded to the intranet as an educational resource available to all staff. Results. The interventions were implemented in July 2022 and BCC rates pre- and post-intervention were calculated. The average BCC rate for the 12 months preceding the intervention (July 2021 to July 2022) was 2.56 % with highest rates in the Emergency Department. This compared to an average rate of 2.2 % in the 12 months post-intervention (July 2022 to July 2023). In comparing the two rates the reduction in BCC rates between the two periods was not statistically significant (P=0.30). Conclusion. Overall BCC rates reduced but the difference between the two periods did not reach statistical significance. The resource-intensive nature of providing regular and timely feedback of contamination rates and the larger impact of in-person education and training over virtual modalities may explain the modest reduction. Further investments in these areas, particularly in the Emergency Department, will be necessary to further reduce rates in line with new recommendations.

BD Chloraprep™ ("2 % chlorhexidine with 70 % isopropyl alcohol") versus povidone iodine plus alcohol, for prevention of blood culture contamination at children: An investigator-initiated, open-label, single centre, randomized controlled trial

INTRODUCTION

One of the important problems that lower the diagnostic value of blood culture is contamination with skin organisms. The povidone-iodine, alcohol, and chlorhexidine gluconate alcohol are used for disinfection prior to blood sampling for culture.

METHODS

The investigator-initiated, open label, single centre, randomised trial compared blood culture contamination rates between two groups of patients in which using a povidone iodine skin-preparation process with the contamination rate for using "2 % chlorhexidine with 70 % isopropyl alcohol" skin-disinfection. The patients who required sampling for blood cultures were included in the study and study period was from 15 March 2023 to 15 July 2023.

RESULTS

A total of 400 blood cultures were obtained during the study, including 133 in the study group and 267 in the control group. In the total blood cultures, 11.75 % (n = 47) had microorganism isolation. Among them 39 (9.75 %) were contaminants and 8 (2 %) of them were true pathogens. The contaminant microorganisms were as following; 34 coagulase-negative Staphylococci, 3 Micrococcus spp, and 2 Streptococci viridans. The blood culture contamination rate in the study group was 5.3 % (n = 7) and 12.0 % (n = 32) in the control group, and significantly lower in the study group (p = 0.033). There is no significant difference regarding skin related side effects between two groups.

CONCLUSIONS

This study, showed that 2 % chlorhexidine gluconate in 70 % isopropyl alcohol is more efficacious in children than 10 % povidone-iodine preparations for disinfecting the skin prior to blood specimen collection for prevention of blood culture contamination.

Bayesian evaluation of sensitivity and specificity of blood culture media and hypoglycemia in sepsis-suspected calves

BACKGROUND

Sepsis is a life-threatening condition for which critically important antimicrobials are often indicated. The value of blood culture for sepsis is indisputable, but appropriate guidelines on sampling and interpretation are currently lacking in cattle.

OBJECTIVE

Compare the diagnostic accuracy of 2 blood culture media (pediatric plus [PP] and plus aerobic [PA]) and hypoglycemia for bacteremia detection. Estimate the contamination risk of blood cultures in critically ill calves.

ANIMALS

One hundred twenty-six critically ill calves, 0 to 114 days.

METHODS

Retrospective cross-sectional study in which the performance of PP, PA and hypoglycemia to diagnose sepsis was assessed using a Bayesian latent class model. A Cox proportional hazards model was used to compare time to positivity (TTP). Potential contamination was descriptively analyzed. Isolates were considered relevant when they were; member of the Enterobacterales, isolated from both blood cultures vials, or well-known, significant bovine pathogens.

RESULTS

The sensitivities for PP, PA, and hypoglycemia were higher when excluding assumed contaminants; 68.7% (95% credibility interval = 30.5%-93.7%), 87.5% (47.0%-99.5%), and 61.3% (49.7%-72.4%), respectively. Specificity was estimated at 95.1% (82.2%-99.7%), 94.2% (80.7%-99.7%), and 72.4% (64.6%-79.6%), respectively. Out of 121 interpretable samples, 14.9% grew a presumed contaminant in PA, PP, or both. There was no significant difference in the TTP between PA and PP.

CONCLUSIONS AND CLINICAL IMPORTANCE

PA and PP appear to outperform hypoglycemia as diagnostic tests for sepsis. PA seems most sensitive, but a larger sample size is required to verify this. Accuracy increased greatly after excluding assumed contaminants. The type of culture did not influence TTP or the contamination rate.

The clinical Spectrum of Viridans Group Streptococci infections in paediatric patients at a tertiary hospital

Background

Viridans Group Streptococci (VGS) are often considered organisms of low virulence; however, infection can result in clinically significant sepsis and life-threatening complications in paediatric patients.

Objectives

This study aimed to describe the spectrum of clinical presentation of VGS bacteraemia in paediatric patients, to analyse risk factors, and to describe the antibiotics resistance patterns of VGS.

Method

Cultures of VGS in paediatric patients admitted to Chris Hani Baragwanath Academic Hospital in 2019 were identified through National Health Laboratory Service. Data were extracted from archived clinical records and analysed. Sepsis scores were calculated at the time of bacteraemia.

Results

A total of 133 cultures were identified; 64 (48.1%) polymicrobial cultures and no records 4 (0.03%) were excluded; 65 (48.9%) were analysed. The median age was 1.5 months (range 0.03 to 168, interquartile range [IQR]: 0.3-13.25), 27/65 (42%) were neonates. The median duration of hospitalisation was 7 days (IQR: 3-21). The commonest diagnoses were neonatal sepsis 30.8% (n = 20) and pneumonia 28% (n = 18). The systemic inflammatory response syndrome (SIRS) score was ≥ 2 in 57% (16/28) patients; paediatric sequential organ failure assessment (pSOFA) score was > 2 in 10/24 (42%). Fifty-seven (88%) patients were discharged; three (5%) required ICU admission and 8/65 (12.3%) died. Malnutrition was present in 50% of patients who died. Cephalosporins and penicillin had sensitivity of 89% and 55%, respectively.

Conclusion

Viridans Group Streptococci bacteraemia was common in neonates, and pneumonia was a common presentation in this cohort. The VGS bacteraemia was associated with morbidity and deaths in this cohort.

Contribution

The VGS should be considered a significant organism when cultured from sterile sites and routine antibiotic susceptibility testing should be performed. Prospective studies are recommended.

Epidemiology and Risk Factors of Early Bacterial Infections After Pediatric Living Donor Liver Transplantation

BACKGROUND

Advancements in surgical techniques, immunosuppression regimens, and peri-operative and postoperative care have resulted in marked improvement in outcomes after pediatric living donor liver transplantation (PLDLT). Despite these developments, infectious complications remain a major cause of morbidity and mortality.

METHODS

This is a retrospective cohort analysis of pediatric recipients from January 2004 to December 2018. Patients were classified into infected and non-infected groups based on the occurrence of bacterial infection during the first 3 months after transplant. Perioperative risk factors for early post-transplant bacterial infections and postoperative outcomes were investigated.

RESULTS

Seventy-two out of 221 children developed early bacterial infection (32.6%). The first episodes of bacterial infection most frequently occurred in the second week after LDLT (37.5%). In multivariate analysis, active infection before transplant and complications with Clavien-Dindo grading >3 were the only independent risk factors. Early bacterial infections were independently associated with longer intensive care unit stays, longer hospital stays, and a higher incidence of readmission for bacterial infection during the first year after transplant. Additionally, the overall patient survival rate was significantly higher in the non-infected group (P = .001). Risk factors for infection, such as age, weight, disease severity, ABO-incompatible, and other operative factors, were not identified as independent risk factors.

CONCLUSION

We have demonstrated that there are similarities and disparities in the epidemiology and risk factors for early bacterial infection after transplant between centers. Identification and better characterization of these predisposing factors are essential in the modification of current preventive strategies and treatment protocols to improve outcomes for this highly vulnerable group.

Using novel micropore technology combined with artificial intelligence to differentiate Staphylococcus aureus and Staphylococcus epidermidis

Methods for identifying bacterial pathogens are broadly categorised into conventional culture-based microbiology, nucleic acid-based tests, and mass spectrometry. The conventional method requires several days to isolate and identify bacteria. Nucleic acid-based tests and mass spectrometry are relatively rapid and reliable, but they require trained technicians. Moreover, mass spectrometry requires expensive equipment. The development of a novel, inexpensive, and simple technique for identifying bacterial pathogens is needed. Through combining micropore technology and assembly machine learning, we developed a novel classifier whose receiver operating characteristic (ROC) curve showed an area under the ROC curve of 0.94, which rapidly differentiated between Staphylococcus aureus and Staphylococcus epidermidis in this proof-of-concept study. Morphologically similar bacteria belonging to an identical genus can be distinguished using our method, which requires no specific training, and may facilitate the diagnosis and treatment of patients with bacterial infections in remote areas and in developing countries.

Rise in the Pathogenic Status of Coagulase-Negative Staphylococci Causing Bloodstream Infection

BACKGROUND

Coagulase-negative staphylococci (CoNS) are one of the frequently isolated bacteria from blood cultures. Since they are part of the normal skin flora, they were previously considered contaminants. But now, they can be considered as established pathogens causing bloodstream infection (BSI). This study aims to estimate the prevalence of CoNS in BSI cases.

METHODS

This study was conducted at the Microbiology Department, All India Institute of Medical Sciences (AIIMS), Raipur, India, for eight months (January 2022 to August 2022). Data were collected retrospectively from medical and laboratory records. Paired blood cultures from 5085 clinically suspected sepsis cases were subjected to aerobic culture for five days in the BacT ALERT 3D system. Pathogenicity was established after recovery of CoNS from paired blood cultures of symptomatic patients.

RESULTS

CoNS were isolated from 2.35% of patients, the most common species being Staphylococcus haemolyticus (51.67%). About 90% of isolates were methicillin-resistant. All the isolates were susceptible to linezolid, teicoplanin, and vancomycin, except one isolate of S. haemolyticus which was intermediate to vancomycin. Minimum inhibitory concentration (MIC) 50 and MIC 90 for vancomycin were 1 ug/ml and 2 ug/ml, respectively.  Conclusion: Paired blood cultures are necessary to determine the pathogenicity of CoNS in BSI cases. A high prevalence of methicillin resistance, accompanied by high resistance rates to other non-beta lactam antibiotics, warrants the strict implementation of antimicrobial stewardship practices.

Development and derivation of bacteremia prediction model in patients with hepatobiliary infection

INTRODUCTION

Hepatobiliary infections are common in the emergency department (ED), and the mortality rate for this condition is high. A suitable bacteremia prediction model would support prompt identification of bacteremia and appropriate management of hepatobiliary infections in the ED. Therefore, we attempted to produce a bacteremia prediction model with both internal and external validation for hepatobiliary infections in the ED.

METHODS

Patients with hepatobiliary infection were extracted from retrospective cohort databases of two tertiary hospitals from January 2018 to December 2019 and from January 2016 to December 2019, respectively. Independent risk factors were determined using multivariable logistic regression in a developmental cohort. We assigned a weighted value to predictive factors and developed a prediction model, which was validated both internally and externally. We assessed discrimination using the area under the receiver operating characteristics curve (AUC).

RESULTS

One hospital cohort of 1568 patients was randomly divided into a developmental group of 927 patients (60%) and an internal validation group of 641 patients (40%), and 736 people from the other hospital cohort were used for external validation. Bacteremia rates were 20.5%, 18.1%, and 23.1% in the developmental, internal, and external validation cohorts, respectively. Nine significant factors were used for predicting bacteremia, including age, three vital signs, and five laboratory tests. After applying our bacteremia prediction rule to the validation cohort, 56.5% and 53.8% of the internal and external validation groups were classified as low-risk bacteremia groups (bacteremia rates: 8.6% and 13.9%, respectively). The AUCs were 0.727 (95% confidence interval [CI]: 0.686-0.767), 0.730 (95% CI: 0.679-0.781), and 0.715 (95% CI: 0.672-0.758) for the developmental, internal, and external validation cohorts, respectively. The sensitivity and specificity for internal validation/external validation was 73.2%/67.6% and 63.0%/60.2%, respectively.

CONCLUSION

A bacteremia prediction model for hepatobiliary infection might be useful to predict the risk of bacteremia. It might also reduce the need for blood culture in low-risk patients.

Bacterial Sequencing Reads in Blood Exome Files from Melanoma and Cervical Cancer Patients are Associated with Cancer Recurrence

Bacteremia poses great risk for morbidity and mortality for immunocompromised cancer patients. Although the presence of bacteria within solid tumors is gaining greater attention, few studies have analyzed species of bacteria in the blood and their effect on cancer clinical outcomes. Using the Kraken 2 taxonomic profiling tool, we classified bacteria present in blood and primary tumors of cervical cancer and melanoma cases. The Cancer Genome Atlas (TCGA) melanoma blood exome files with Pseudomonas species were found to represent a worse disease-free survival (DFS) probability, while a worse overall survival (OS) result was evidenced for both the TCGA and Moffitt Cancer Center melanoma datasets. Cervical cancer cases with reads representing the Bradyrhizobium genus and Bradyrhizobium sp. BTAi1 found in blood and tumor exome files were found to have lower DFS. Additionally, reduced DFS and OS were observed for cervical cancer cases positive for Bacteroides species including Bacteroides fragilis. This study provides novel evidence and a novel approach for indicating that bacteria in blood is associated with cancer recurrence. These findings may guide the development of more efficient prognostic and screening tools related to bacterial blood infections of melanoma and cervical cancer patients.

Getting to zero: Impact of a device to reduce blood culture contamination and false-positive central-line-associated bloodstream infections

OBJECTIVE

To assess the impact of initial specimen diversion device (ISDD) on inpatient and emergency department blood culture contamination (BCC), central-line-associated bloodstream infection (CLABSI) standardized infection ratios (SIRs), and antibiotic administration.

DESIGN

Single-center quasi-experimental prospective cohort study wherein phlebotomists used traditional venipuncture with or without the ISDD while registered nurses (RNs) used traditional venipuncture.

METHOD

BCC events among phlebotomists and RNs were observed and compared from March 17, 2019, through January 21, 2020, defined by contaminant detection in 1 of 4 bottles for matched sets or 1 of 2 bottles in both subsets for coagulase negative staphylococci. CLABSIs throughout this period were recorded and SIRs were calculated. Enhanced oversight took place through July 21, 2019, with chart review assessing antibiotic use for patients with possible BCC.

RESULTS

Overall, 24% of blood cultures obtained were from patients in intensive care. Phlebotomists using traditional venipuncture (n = 4,759) had a 2.3% BCC rate; phlebotomists using the ISDD (n = 11,202) had a 0% BCC rate. RNs drew 7,411 BCs with a 0.8% BCC rate. The CLABSI SIR was decreased from 1.103 in 2017 and 0.658 in 2018 to 0.439 in 2019. The CLABSI incidence was 33%-64% of predicted value for each 2019 quarter. This range fell to 18%-37% after the exclusion of likely false-positive results. Among 42 patients with possible BCC under enhanced oversight, 2 patients were treated with prolonged antibiotic courses.

CONCLUSIONS

ISDD use by phlebotomists was associated with BCC reduction and reduced false-positive CLABSI results. This patient-care quality improvement could constitute sustainable antibiotic stewardship expansion.

Hemoglobin and Its Z Score Reference Intervals in Febrile Children: A Cohort Study of 98,572 Febrile Children

OBJECTIVES

Febrile disease and age of children were associated with a variation in hemoglobin (Hb) level. Both CRP and Hb serve as laboratory markers that offer valuable insights into a patient's health, particularly in relation to inflammation and specific medical conditions. Although a direct correlation between CRP and Hb levels is not established, the relationship between these markers has garnered academic attention and investigation. This study aimed to determine updated reference ranges for Hb levels for age and investigated its correlation with CRP in febrile children under the age of 18.

METHODS

This is a cohort study of in Chang Gung Memorial Hospitals conducted from January 2010 to December 2019. Blood samples were collected from 98,572 febrile children who were or had been admitted in the pediatric emergency department. The parameters of individuals were presented as the mean ± standard deviation or 2.5th and 97.5th percentiles. We also determined the variation of Hb and Z score of Hb between CRP levels in febrile children.

RESULT

We observed that the Hb levels were the highest immediately after birth and subsequently underwent a rapid decline, reaching their lowest point at around 1-2 months of age, and followed by a steady increment in Hb levels throughout childhood and adolescence. In addition, there was a significant and wide variation in Hb levels during the infant period. It revealed a significant association between higher CRP levels and lower Hb levels or a more negative Z score of Hb across all age subgroups. Moreover, in patients with bacteremia, CRP levels were higher, Hb concentrations were lower, and Z scores of Hb were also lower compared to the non-bacteremia group. Furthermore, the bacteremia group exhibited a more substantial negative correlation between CRP levels and a Z score of Hb (r = -0.41, p < 0.001) compared to the non-bacteremia group (r = -0.115, p < 0.049).

CONCLUSION

The study findings revealed that the Hb references varied depending on the age of the children and their CRP levels. In addition, we established new reference values for Hb and its Z scores and explore their relationship with CRP. It provides valuable insights into the Hb status and its potential association with inflammation in febrile pediatric patients.

Verification of quality assurance for blood culture surveillance using 6 years of data from the Japan Infection Prevention and Control Conference for National and Public University Hospitals

The importance of blood culture has been widely recognized, and there is a need for monitoring to evaluate the accuracy of blood culture that reflects domestic healthcare systems. In this study, we assessed 6-year trends in blood culture quality assurance data. The Japan Infection Prevention and Control Conference for National and Public University Hospitals conducted yearly blood culture surveillance at 52 national public university hospitals from 2015 to 2020. Statistical analysis showed that comparison with the previous year showed significant differences in the number of blood cultures per 1000 patient-days in all years. The number of blood cultures per 1000 admissions was not significantly different in 2017 and 2018, but significant differences were shown in all other years. The multiple blood culture set rate was significantly different between non-pediatric inpatients and outpatients but not between pediatric inpatients and outpatients. The contamination rate did not differ significantly. For all parameters, significant differences were found when comparing 2015 and 2020. Our survey showed that although the sample number improved over time, even the most recent values for 2020 were lower than Cumitech's targets. It is difficult to assess whether these sample numbers are appropriate because target values have not been set for the various types of hospitals in Japan. Surveillance is a useful tool for monitoring quality assurance for blood culture. All parameters improved over the 6-year period, but it is necessary to establish a benchmark for evaluating optimization. We will continue to monitor quality assurance and work on setting benchmarks.

Delta Neutrophil Index Does Not Differentiate Bacterial Infection without Bacteremia from Viral Infection in Pediatric Febrile Patients

Introduction: We sought to determine whether the delta neutrophil index (DNI), a marker that is reported to be used to predict the diagnosis, prognosis, and disease severity of bacteremia and sepsis, is useful in differentiating bacterial infection without bacteremia (BIWB) from viral infections (VI) in pediatric febrile patients in the emergency department (ED). Method: We conducted a retrospective analysis of febrile patients’ medical records from the pediatric ED of the teaching hospital. The patients with BIWB and those with VI were identified with a review of medical records. The primary outcome was the diagnostic performance of DNI in differentiating BIWB from VI. The secondary outcome was a comparison of the diagnostic performances of DNI, CRP, WBC, and neutrophil count between the two groups. Results: A total of 151 (26.3%) patients were in the BIWB group, and 423 (73.7%) were in the VI group. There was no significant difference in DNI between the two groups (3.51 ± 6.90 vs. 3.07 ± 5.82, mean ± SD, BIWB vs. VI). However, CRP levels were significantly higher in the BIWB group than in the VI group (4.56 ± 5.45 vs. 1.39 ± 2.12, mean ± SD, BIWB vs. VI, p < 0.05). The AUROCs of DNI, WBC count, neutrophil levels, RDW, and CRP levels were 0.5016, 0.5531, 0.5631, 0.5131, and 0.7389, respectively, and only CRP levels were helpful in differentiating BIWB from VI. Conclusion: In the absence of bacteremia, DNI would not be helpful in differentiating BIWB from VI in pediatric febrile patients.

Machine learning algorithm as a prognostic tool for venous thromboembolism in allogeneic transplant patients

As a serious complication after allogenic hematopoietic stem cell transplantation (allo-HSCT), venous thromboembolism (VTE) is significantly related to increased nonrelapse mortality. Therefore distinguishing patients at high risk of death who should receive specific therapeutic management is key to improving survival. This study aimed to establish a machine learning-based prognostic model for the identification of post-transplantation VTE patients who have a high risk of death. We retrospectively evaluated 256 consecutive VTE patients who underwent allo-HSCT at our center between 2008 and 2019. These patients were further randomly divided into (1) a derivation (80%) cohort of 205 patients and (2) a test (20%) cohort of 51 patients. The least absolute shrinkage and selection operator (LASSO) approach was used to choose the potential predictors from the primary dataset. Eight machine learning classifiers were used to produce 8 candidate models. A 10-fold cross-validation procedure was used to internally evaluate the models and to select the best-performing model for external assessment using the test cohort. In total, 256 of 7238 patients were diagnosed with VTE after transplantation. Among them, 118 patients (46.1%) had catheter-related venous thrombosis, 107 (41.8%) had isolated deep-vein thrombosis (DVT), 20 (7.8%) had isolated pulmonary embolism (PE), and 11 (4.3%) had concomitant DVT and PE. The 2-year overall survival (OS) rate of patients with VTE was 68.8%. Using LASSO regression, 8 potential features were selected from the 54 candidate variables. The best-performing algorithm based on the 10-fold cross-validation runs was a logistic regression classifier. Therefore a prognostic model named BRIDGE was then established to predict the 2-year OS rate. The areas under the curves of the BRIDGE model were 0.883, 0.871, and 0.858 for the training, validation, and test cohorts, respectively. The Hosmer-Lemeshow goodness-of-fit test showed a high agreement between the predicted and observed outcomes. Decision curve analysis indicated that VTE patients could benefit from the clinical application of the prognostic model. A BRIDGE risk score calculator for predicting the study result is available online (47.94.162.105:8080/bridge/). We established the BRIDGE model to precisely predict the risk for all-cause death in VTE patients after allo-HSCT. Identifying VTE patients who have a high risk of death can help physicians treat these patients in advance, which will improve patient survival.

Pattern of Antimicrobial Susceptibility and Antimicrobial Treatment of Neonates Admitted with Suspected Sepsis in a Teaching Hospital in Ghana, 2021

Neonatal sepsis is a life-threatening emergency, and empirical antimicrobial prescription is common. In this cross-sectional study of neonates admitted with suspected sepsis in a teaching hospital in Ghana from January-December 2021, we described antimicrobial prescription patterns, compliance with national standard treatment guidelines (STG), blood culture testing, antimicrobial resistance patterns and treatment outcomes. Of the 549 neonates admitted with suspected sepsis, 283 (52%) were males. Overall, 529 (96%) received empirical antimicrobials. Most neonates (n = 407, 76.9%) were treated empirically with cefuroxime + gentamicin, while cefotaxime was started as a modified treatment in the majority of neonates (46/68, 67.6%). Only one prescription complied with national STGs. Samples of 257 (47%) neonates underwent blood culture testing, of which 70 (27%) were positive. Isolates were predominantly Gram-positive bacteria, with coagulase-negative Staphylococcus and Staphylococcus aureus accounting for 79% of the isolates. Isolates showed high resistance to most penicillins, while resistance to aminoglycosides and quinolones was relatively low. The majority of neonates (n = 497, 90.5%) were discharged after successfully completing treatment, while 50 (9%) neonates died during treatment. Strengthening of antimicrobial stewardship programmes, periodic review of STGs and increased uptake of culture and sensitivity testing are needed to improve management of sepsis.

Comparative of clinical performance between next-generation sequencing and standard blood culture diagnostic method in patients suffering from sepsis

BACKGROUND

Next-generation sequencing (NGS) is a massively unbiased sequencing technology. The objective of this study was to evaluate the performance of NGS-based approach in the detection of microorganisms from septic patients and compare with results of blood culture (BC).

METHODS

The observational and non-interventional study was conducted from April 2019 to August 2019.

RESULTS

A total of 96 sets of BC and 48 NGS results obtained from 48 septic patients were analyzed in this study. Thirty-two microorganisms (27 bacteria, 3 fungi and 2 viral) were detected by NGS in 23 (47.9%) patients; and 18 bacteria in 18 (37.5%) patients by BC. Exclusion of skin commensals, the positivity of NGS and BC was 62.5% and 14.5%, respectively (P < 0.001). Microorganisms identified by NGS demonstrated positive agreement with BC in 12 (25%) patients, including concordant results in 11 (22.9%) cases, and discrepancy results in 1 (2%). Of 11 patients with concordant results, 4 had additional microorganisms detected by NGS. NGS-positive but BC-negative was found in 9 (18.7%) patients. Using NGS, difficult-to-culture micro-organisms such as Pneumocystic jirovecii was identified in 2 patients, and Leptospira interrogans in one. Six (12.5%) patients with BC-positive but NGS-negative, whereas skin commensals were isolated in 4 (66.6%) cases. The number of patients that were positive by BC only increase from 29% to 47.9% when combining NGS and BC analyses (P = 0.033).

CONCLUSIONS

Our study support the advantage of NGS for the diagnosis of infecting microorganisms in sepsis, especially for microorganisms that are currently difficult or impossible to culture.

The characteristics of bacteremia among patients with acute febrile illness requiring hospitalization in Indonesia

Blood culturing remains the "gold standard" for bloodstream infection (BSI) diagnosis, but the method is inaccessible to many developing countries due to high costs and insufficient resources. To better understand the utility of blood cultures among patients in Indonesia, a country where blood cultures are not routinely performed, we evaluated data from a previous cohort study that included blood cultures for all participants. An acute febrile illness study was conducted from July 2013 to June 2016 at eight major hospitals in seven provincial capitals in Indonesia. All participants presented with a fever, and two-sided aerobic blood cultures were performed within 48 hours of hospital admission. Positive cultures were further assessed for antimicrobial resistance (AMR) patterns. Specimens from participants with negative culture results were screened by advanced molecular and serological methods for evidence of causal pathogens. Blood cultures were performed for 1,459 of 1,464 participants, and the 70.6% (1,030) participants that were negative by dengue NS1 antigen test were included in further analysis. Bacteremia was observed in 8.9% (92) participants, with the most frequent pathogens being Salmonella enterica serovar Typhi (41) and Paratyphi A (10), Escherichia coli (14), and Staphylococcus aureus (10). Two S. Paratyphi A cases had evidence of AMR, and several E. coli cases were multidrug resistant (42.9%, 6/14) or monoresistant (14.3%, 2/14). Culture contamination was observed in 3.6% (37) cases. Molecular and serological assays identified etiological agents in participants having negative cultures, with 23.1% to 90% of cases being missed by blood cultures. Blood cultures are a valuable diagnostic tool for hospitalized patients presenting with fever. In Indonesia, pre-screening patients for the most common viral infections, such as dengue, influenza, and chikungunya viruses, would maximize the benefit to the patient while also conserving resources. Blood cultures should also be supplemented with advanced laboratory tests when available.

Initial Specimen Diversion Device Utilization Mitigates Blood Culture Contamination Across Regional Community Hospital and Acute Care Facility

A West Virginia regional community hospital incorporated an initial specimen diversion device (ISDD) into conventional blood culture protocol with the objective to bring the hospital-wide blood culture contamination (BCC) rate from a 3.06% preintervention rate to a target performance level below 1%. Emergency department staff, laboratory phlebotomists, and nursing staff on acute-critical care floors were trained on ISDD (Steripath Gen2, Magnolia Medical Technologies, Inc., Seattle, WA) operating procedure and utilized the device for blood culture sample collection with adult patients from September 2020 through April 2021. Of 5642 blood culture sets collected hospital-wide, 4631 were collected with the ISDD, whereas the remaining sets were collected via the conventional method. The ISDD BCC rate of 0.78% differed from the conventional method BCC rate of 4.06% observed during the intervention period (chi-squared test P < 0.00001). The ISDD group attained a sub-1% BCC rate to satisfy the intervention objective.

Postmortem Bacteriology in Forensic Autopsies—A Single Center Retrospective Study in Romania

Postmortem bacteriology examinations have been a controversial topic over the years, though the value of postmortem bacteriology cultures remains promising. The aim of this study was to review the postmortem bacteriological sampling procedures and results in a single centre in Bucharest over a period of 10 years. Material and methods: The present study was a retrospective, single-center study, performed at the Mina Minovici National Institute of Legal Medicine in Bucharest, Romania, from 2011–2020. Results: Postmortem bacteriology was requested 630 forensic autopsies, 245 female (38.9%) and 385 male (61.1%), age range 0 and 94 years, median age of 52 years. Deaths occurred in hospital for 594 cases (94.3%) and out-of-hospital for 36 cases (5.7%—field case). Blood cultures were requested in the majority of cases, followed by tracheal swabs and lung tissue. In-hospital and out of hospital deaths did not differ significantly regarding the number of microorganisms identified in a positive blood culture. Postmortem bacteriology cultures of the respiratory tract showed a statistically significant association to microscopically confirmed lung infections. Conclusions Postmortem sampling for bacteriology testing in our center in Bucharest is heterogeneous with a high variation of patterns. A positive blood culture result for Staphylococcus species without the identification of a specific microorganism is more likely due to postmortem contamination.

The Diagnostic Values of Peptidoglycan, Lipopolysaccharide, and (1,3)-Beta-D-Glucan in Patients with Suspected Bloodstream Infection: A Single Center, Prospective Study

This study aimed to assess the diagnostic values of peptidoglycan (PGN), lipopolysaccharide (LPS) and (1,3)-Beta-D-Glucan (BDG) in patients with suspected bloodstream infection. We collected 493 heparin anticoagulant samples from patients undergoing blood culture in Peking Union Medical College Hospital from November 2020 to March 2021. The PGN, LPS, and BDG in the plasma were detected using an automatic enzyme labeling analyzer, GLP-F300. The diagnostic efficacy for PGN, LPS, and BDG were assessed by calculating the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). This study validated that not only common bacteria and fungi, but also some rare bacteria and fungi, could be detected by testing the PGN, LPS, and BDG, in the plasma. The sensitivity, specificity, and total coincidence rate were 83.3%, 95.6%, and 94.5% for PGN; 77.9%, 95.1%, and 92.1% for LPS; and 83.8%, 96.9%, and 95.9% for BDG, respectively, which were consistent with the clinical diagnosis. The positive rates for PGN, LPS, and BDG and the multi-marker detection approach for PGN, LPS, and BDG individually were 11.16%, 17.65%, and 9.13%, and 32.86% significantly higher than that of the blood culture (p < 0.05). The AUC values for PGN, LPS, and BDG were 0.881 (0.814−0.948), 0.871 (0.816−0.925), and 0.897 (0.825−0.969), separately, which were higher than that of C-reactive protein (0.594 [0.530−0.659]) and procalcitonin (0.648 [0.587−0.708]). Plasma PGN, LPS, and BDG performs well in the early diagnosis of bloodstream infections caused by Gram-positive and Gram-negative bacterial and fungal pathogens.

Blood Culture Contamination Rate as a Quality Indicator - a Prospective Observational Study

Introduction: Blood culture test is the gold standard test to diagnose bloodstream infections, but contamination is the main problem in this valuable test. False positive results in blood cultures are mainly due to contamination that occurs mostly during pre-analytical procedures like sample collection and sometimes during sample processing. Materials and method:Our prospective observational study was undertaken at St. Theresa Hospital, Hyderabad, India, during January 2020-June 2020. Blood cultures received from inpatient departments (IPD) and outpatient departments (OPD) are included. Sample size: The contamination rate was calculated by dividing the total number of contaminated blood cultures by the total number of cultures multiplied by 100. Results:Blood culture contamination rate is 2.4%, which is within the limit as per the standard guideline. Conclusion:Contamination occurred mainly due to improper disinfection of the skin and environmental contamination.

Clinical and microbiological characteristics of polymicrobial bacteremia: a retrospective, multicenter study

PURPOSE

To clarify the clinical and microbial characteristics of polymicrobial bacteremia (PMB) to contribute to improvements in clinical diagnosis and effective early treatment.

METHODS

This retrospective multicenter study used data from three acute-care hospitals in Okayama Prefecture, Japan, collected between January 2014 and March 2019. We reviewed the demographics, comorbidities, organisms isolated, infectious focus, and 30-day mortality of patients with PMB.

RESULTS

Of the 7233 positive blood cultures, 808 (11.2%) were positive for more than one organism. Of the patients with bacteremia, 507 (7.0%) had PMB, of whom 65.3% were male. Infectious foci were identified in 78.3% of the cases, of which intra-abdominal infections accounted for 47.1%. A combination of Gram-positive cocci (GPC) (chain form) and Gram-negative rods (GNR) accounted for 32.9% of the cases, and GPC/GNR and GNR/GNR patterns were significantly associated with intra-abdominal infections. The 30-day mortality rate of patients with PMB was 18.1%, with a median of 7.5 days from diagnosis to death. The mortality in patients with an infectious focus identified was significantly lower than that in patients with an unknown focus (16.3% vs. 24.5%; p = 0.031).

CONCLUSIONS

Intra-abdominal infections were the most common source of PMB, and were strongly associated with a Gram-staining combination pattern of GPC (chain form)/GNR. PMB cases with an unknown focus had a poorer prognosis, highlighting the importance of early diagnosis and appropriate treatment.

Blood Culture Contamination: A Single General Hospital Experience of 2-Year Retrospective Study

In the event of blood culture contamination (BCC), blood culture (BC) needs to be repeated. This may delay appropriate treatment, prolong hospitalization and, consequently, increase its costs. The aim of the study was to assess the frequency of BCC and associated factors in a general hospital in Poland based on reports of BC in samples submitted for laboratory testing in 2019−2020. BCC is recognized when bacteria (especially those belonging to natural human microbiota) are isolated from a single sample and no clinical signs indicated infection. True positive BC is confirmed by the growth of bacteria in more than one set of blood samples with the corresponding clinical signs present. The structure of BC sets, microorganisms, and laboratory costs of BCC were analyzed. Out of 2274 total BC cases, 11.5% were true positive BC and 9.5% were BCC. Of all the BCC identified in the entire hospital, 72% was from Internal Medicine (IM) and Intensive Care Unit (ICU) combined. When single sets for BC were used in IM in 2020, the use increased to 85% compared with 2019 (p < 0.05). The predominant isolates were coagulase-negative staphylococci (84%). The estimated extra laboratory costs of BCC exceeded EUR 268,000. The BCC was a more serious problem than expected, including non-recommended using of single BC sets. Compliance with the BC collection procedure should be increased in order to reduce BCC and thus extra hospital costs.

Prediction of bacteremia at the emergency department during triage and disposition stages using machine learning models

INTRODUCTION

Bacteremia is a common but critical condition with high mortality that requires timely and optimal treatment in the emergency department (ED). The prediction of bacteremia at the ED during triage and disposition stages could support the clinical decisions of ED physicians regarding the appropriate treatment course and safe ED disposition. This study developed and validated machine learning models to predict bacteremia in the emergency department during triage and disposition stages.

METHODS

This study enrolled adult patients who visited a single tertiary hospital from 2016 to 2018 and had at least two sets of blood cultures during their ED stay. Demographic information, chief complaint, triage level, vital signs, and laboratory data were used as model predictors. We developed and validated prediction models using 10 variables at the time of ED triage and 42 variables at the time of disposition. The extreme gradient boosting (XGB) model was compared with the random forest and multivariable logistic regression models. We compared model performance by assessing the area under the receiver operating characteristic curve (AUC), test characteristics, and decision curve analysis.

RESULTS

A total of 24,768 patients were included: 16,197 cases were assigned to development, and 8571 cases were assigned to validation. The proportion of bacteremia was 10.9% and 10.4% in the development and validation datasets, respectively. The Triage XGB model (AUC, 0.718; 95% confidence interval (CI), 0.701-0.735) showed acceptable discrimination performance with a sensitivity over 97%. The Disposition XGB model (AUC, 0.853; 95% CI, 0.840-0.866) showed excellent performance and provided the greatest net benefit throughout the range of thresholds probabilities.

CONCLUSIONS

The Triage XGB model could be used to identify patients with a low risk of bacteremia immediately after initial ED triage. The Disposition XGB model showed excellent discriminative performance.

A new molecular method for rapid etiological diagnosis of sepsis with improved performance

The value of blood cultures for confirming the clinical diagnosis of sepsis is suboptimal. There is growing interest in the potential of real-time PCR technology by detection of minute amounts of pathogen DNA in patient blood samples with results available within 4-6 h. Adopting a two-step approach, we evaluated the compliance of two versions of the MicrobScan assay on a total of 748 patients with suspected bloodstream infections. The results obtained with a second version of the MicrobScan assay are characterized by increased specificity (from 95.1 to 98.2%) and sensitivity (from 76.7 to 85.1), increased throughput and the possibility of simultaneously testing different kinds of samples collected from the potential sites of infection and utilizing different syndromic panels.

Antibiotic regimens for late-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units, and observational studies in high-income countries suggest that 83% to 94% of newborns treated with antibiotics for suspected sepsis have negative blood cultures. The last Cochrane Review was updated in 2005. There is a need for an updated systematic review assessing the effects of different antibiotic regimens for late-onset neonatal sepsis.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for late-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2021, Issue 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for late-onset neonatal sepsis. We included participants older than 72 hours of life at randomisation, suspected or diagnosed with neonatal sepsis, meningitis, osteomyelitis, endocarditis, or necrotising enterocolitis. We excluded trials that assessed treatment of fungal infections.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (580 participants). All trials were at high risk of bias, and had very low-certainty evidence. The five included trials assessed five different comparisons of antibiotics. We did not conduct a meta-analysis due to lack of relevant data. Of the five included trials one trial compared cefazolin plus amikacin with vancomycin plus amikacin; one trial compared ticarcillin plus clavulanic acid with flucloxacillin plus gentamicin; one trial compared cloxacillin plus amikacin with cefotaxime plus gentamicin; one trial compared meropenem with standard care (ampicillin plus gentamicin or cefotaxime plus gentamicin); and one trial compared vancomycin plus gentamicin with vancomycin plus aztreonam. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. RCTs assessing different antibiotic regimens in late-onset neonatal sepsis with low risks of bias are warranted.

Determinants and outcomes of bloodstream infection in adults associated with one versus two sets of positive index blood cultures

OBJECTIVES

To investigate whether positivity in one or both index sets of blood cultures influences clinical determinants and mortality when diagnosing bloodstream infections (BSI).

METHODS

Retrospective population-based surveillance of all mono-microbial BSI was conducted among residents of the western interior of British Columbia. Clinical details were obtained by chart review and all-cause case-fatality was established at 30 days. Index cultures were defined as the first two sets of cultures initially drawn to diagnose incident BSI.

RESULTS

A total of 2500 incident BSI were identified of which 945 (37.8%) and 1555 (62.2%) were based on one and two positive index cultures, respectively. There was an overall difference in the distribution of pathogens, with both Staphylococcus aureus and Streptococcus pneumoniae more likely to have two positive index cultures. Different foci of infection were associated with one versus two positive index cultures. Overall, 409 patients died within 30 days of index BSI for an all-cause case-fatality of 16.4%; with no difference between two positive (250/1555; 16.1%) and one positive (159/945; 16.8%; p 0.3) index blood culture. The number of positive index blood cultures was not associated with 30-day case-fatality after adjustment for confounding variables using logistic regression analysis.

CONCLUSIONS

Although approximately one-third of BSI are diagnosed on the basis of a single positive blood culture and are associated with different clinical determinants, whether one or both index blood cultures are positive is not associated with lethal outcome.

Development and validation of a screening tool for early identification of bloodstream infection in acute burn injury patients

BACKGROUND

Standard diagnostic criteria are not useful for identifying bloodstream infection in patients with an acute burn injury patients. The study objective was to develop and validate a tool using common laboratory, clinical, and patient parameters for early identification of bloodstream infection after acute burn injury (within 10 days after a burn).

METHODS

We retrospectively and prospectively reviewed for tool development the hospital course of patients with an acute burn injury (n = 156) and validated the tool in different cohorts (retrospective [n = 26] and prospective [n = 90]). The Pearson correlation identified independent variables associated with bloodstream infection (P < .1) in the development cohort that were then analyzed using binary logistic regression to identify the simplest model (P < .05; adjusted odds ratio >1). Classification and regression tree analysis was used to identify tool parameter breakpoints. Performance metrics were completed to evaluate and validate the tool.

RESULTS

The best model (P < .05) was: Ln [odds of bloodstream infection] = -96.749 + 3.230 (platelet volatility) + 2.235 (max temperature [°C]) + 0.339 (% full burn) + 0.242 (% partial burn) + 0.045 (max heart rate [bpm]), with a threshold probability categorizing bloodstream infection of >48%. The sensitivity, specificity, accuracy, false positive rate, false negative rate, and positive (+) and negative (-) likelihood ratios of the tool in the developmental cohort (n = 156) were 89%, 98%, 96%, 2%, 11%, 53, and 0·11, respectively; and in the prospective validation cohort (n = 90 were 91%, 90%, 90%, 10%, 9%, 9, and 0·1, respectively (n = 90).

CONCLUSION

The validated bloodstream infection screening tool in patients with acute burn injury has excellent predictive ability to assist in the identification of patients for whom blood cultures should be requested.

Antibiotic use and presumptive pathogens in the Veterans Affairs Healthcare System

BACKGROUND

Empirical antibiotic use is common in the hospital. Here, we characterize patterns of antibiotic use, infectious diagnoses, and microbiological lab results among hospitalized patients and aim to quantify the proportion of antibiotic use that is potentially attributable to specific bacterial pathogens.

METHODS

We conducted an observational study using electronic health records from acute care facilities in the United States Veterans Affairs Healthcare System. From October 2017 to September 2018, 482,381 hospitalizations for 332,657 unique patients that met all criteria were included. At least one antibiotic was administered at 202,037 (41.9%) of included hospital stays. We measured frequency of antibiotic use, microbiological specimen collection, and bacterial isolation by diagnosis category and antibiotic group. A tiered system based on specimen collection sites and diagnoses was used to attribute antibiotic use to presumptive causative organisms.

RESULTS

Specimens were collected at 130,012 (64.4%) hospitalizations with any antibiotic use, and at least one bacterial organism was isolated at 35.1% of these stays. Frequency of bacterial isolation varied widely by diagnosis category and antibiotic group. Under increasingly lenient criteria, 10.2% to 31.4% of 974,733 antibiotic days-of-therapy could be linked to a potential bacterial pathogen.

CONCLUSIONS

Overall, the vast majority of antibiotic use could be linked to either an infectious diagnosis or microbiological specimen. Nearly half of antibiotic use occurred when there was a specimen collected but no bacterial organism identified, underscoring the need for rapid and improved diagnostics to optimize antibiotic use.

Epidemiological features and outcomes of patients with psoas abscess: A retrospective cohort study

Background

Psoas abscess (PA) is an uncommon disease. Although PA is associated with significant morbidity and mortality, its epidemiology and clinical characteristics remain unknown. This study aimed to evaluate the epidemiological and clinical features and outcomes of patients with PA in a prefectural-wide study.

Materials and methods

This was a multicenter retrospective cohort study conducted between 2010 and 2012 in the Miyagi prefecture with a population of 2,344,062 in 2011. Adult patients with PA were enrolled from 71 secondary and tertiary care hospitals.

Results

There were 57 patients with adult PA in the Miyagi prefecture. The median age of the patients was 72 years, and 67% patients were male. Fever and flank pain were the primary symptoms in 82% and 74% of patients, respectively. Ten patients (18%) had septic shock, and the hospital mortality rate was 12%. Secondary PA was present in 72% of cases, and the most common origin was pyogenic spondylitis. Of the patients with secondary PA, 44% had an epidural abscess. The most common pathogens were Staphylococcus aureus, and 11% (6 cases) of the cases were caused by methicillin-resistant S. aureus.

Conclusion

In the Miyagi prefecture of Japan, the estimated prevalence of PA was 1.21/100,000 population years and hospital mortality was 12%. Secondary PA accounted for more than 70% of the cases, and S. aureus was the most common causative pathogen.

•

The hospital mortality rate of psoas abscess (PA) was 12% in Japan.

•

Estimated prevalence of PA was 1.21/10,000 population years between 2010 and 2012.

•

Secondary PA: >70% of cases with the most common origin as pyogenic spondylitis.

•

Epidural abscess formed in 44% of patients.

•

The most common pathogen was Staphylococcus aureus.

Predictive performance of critical illness scores and procalcitonin in sepsis caused by different gram-stain bacteria

OBJECTIVES

To compare the early and late predictive values of several critical illness scores (CISs) and biomarkers in sepsis-3 patients with bloodstream infections (BSIs) and to identify the prognostic value of procalcitonin (PCT) for different gram-stain bacteria infections.

METHODS

Patients with at least one positive blood culture within 24h of emergency department admission and with a final diagnosis of sepsis/septic shock were enrolled. CISs were calculated based on the first parameters on the day of admission. The receiver operating characteristics curve was used to analyze the predictive value of CISs and biomarkers for early and late mortality.

RESULTS

Of 834 enrolled patients with sepsis-3, death occurred in 214 patients within 28 days and in 273 patients within 60 days. Compared with biomarkers, CISs showed a significantly higher area under the curve (AUC) in the prediction of early and late mortality (p<0.01), especially for patients with GNB infection. The Sequential Organ Failure Assessment score showed a higher AUC for predicting early mortality than the Mortality in Emergency Department Sepsis score (p=0.036). Compared with GNB infections, the AUC values of the PCT for gram-positive bacteria (GPB) infections were higher for predicting early or late mortality; PCT showed higher AUC than high-sensitivity C-reactive protein and white blood cells for predicting early mortality (p<0.05).

CONCLUSIONS

CISs were more advantageous in the assessment of early and late prognosis, especially for patients with GNB infections; however, for sepsis with GPB infection, PCT can be used for the prediction of early mortality.

Prevalence of Bacteria in Primary Schools

Pathogenic microorganisms are serious threats in schools, where contact with many microorganisms occur frequently throughout the school day. Classrooms are considered an optimal place for contact between microorganisms and young children. The aim of the current study was to study the prevalence of bacteria isolated in samples from different sites in primary schools and to show whether schools are sanitized and clean for children or it is just the core reason for their illness. The study was done in a highly standard private school and a public school in order to study the effect of variance in the social classes on the cleanliness of the schools. Different colonies were separated and identified by staining techniques and biochemical tests. Thirteen different types of bacteria with different amounts were isolated from 176 samples collected from different surfaces. It was found that the number of bacteria in public school is higher than that of the private school. The distribution of bacterial strains isolated from the two schools averaged 37.1% for Staphylococcus sp. followed by 11.3% for Enterobacter sp. and then 7.3%, 7.1% and 6.3% for Yersinia sp. Streptococcus sp. and Micrococcus sp. respectively. Other strains ranged between 5.9% to 1.5%. Bacterial isolates were tested for their susceptibility by well diffusion test against three commercial disinfectants commonly used for surface and hand cleaning in schools, namely; Clorox, Renol and Dettol. The highest percentage of resistance was seen against Renol (50%) followed by Dettol (38%) and was identified to be Escherichia coli, while least resistance occurring among all isolates was noticed against Clorox (18%). Children in private and public schools are at high risk of catching serious bacterial infections and they are surrounded by a cram of microorganisms. The current research shows that new ways must be developed to improve our schools’ hygiene to make it a healthier and safer place to learn in.

Blood culture quality assurance: what Australasian laboratories are measuring and opportunities for improvement

Blood cultures are among the most important specimen types received and processed by the microbiology laboratory. Several publications list which variables should be measured to ensure quality. We undertook a qualitative structured questionnaire of Australian and New Zealand clinical microbiology laboratories to document current blood culture practices and to determine whether expected quality standards are being met. Questions included a wide range of pre-analytical, analytical, and post-analytical aspects of blood cultures from adults. The responses from 71 laboratories were analysed. Compliance was high for use of a biological safety cabinet (90%), incubating for 5 days (86%), and commenting on likely contaminants (85%). While Gram stains were reported within 2 hours during normal hours (93%), reporting was slower after hours (59%), p<0.001. The volume of blood collected for a clinical episode was poorly monitored with only 11% (n=8) of laboratories regularly auditing the number of blood culture sets and 3% (n=2) monitoring adequacy of fill. Most laboratories received blood cultures from off-site with just 34% (n=21) meeting guidance for loading bottles onto the analyser within 4 hours. More laboratories met standards for loading bottles onto the analyser during working hours than after hours: 87% vs 56%, p<0.001. Most laboratories did not monitor the contamination rate, 56% (n=40), and only 27% (n=19) knew their rate was below the guidance threshold of less than -3%. Considerable opportunities exist to improve quality assurance of blood culture practice in Australia and New Zealand, especially for the most critical aspect affecting culture sensitivity, the volume of blood collected.

Modern Blood Culture: Management Decisions and Method Options

The optimal care of septic patients depends on the successful recovery of clinically relevant microorganisms from blood cultures and the timely reporting of organism identification and antimicrobial susceptibility testing (AST) results. Many preanalytic factors play a critical role in culturing microorganisms, and advancements in blood culture instrument technology have reduced the time to positive results. Additionally, rapid organism identification and AST results directly from positive blood culture broth via new methods help to further shorten the time from empiric to targeted treatment. This article summarizes the current state of blood culture methods, including preanalytic, analytical, and postanalytic factors that are available to clinical microbiology laboratories.

Efficient Early Diagnosis of Sepsis Using Whole-Blood PCR-Reverse Blot Hybridization Assay Depending on Serum Procalcitonin Levels

Sepsis is one of the medical emergencies, and its early detection, within the first hours of development, and proper management improve outcomes. Molecular diagnostic assays using whole blood collected from patients with suspected sepsis have been developed, but the decision making is difficult because of the possibility of false positives, due to contamination. Here, we evaluated the performance of the reverse blot hybridization assay (REBA) Sepsis-ID test for the detection of sepsis-causing microorganisms using whole-blood samples. In addition, the concentrations of C-reactive protein (CRP) and procalcitonin (PCT) were determined to evaluate whether these biomarkers can provide criteria for performing REBA Sepsis-ID in clinical settings. For this study, EDTA-anticoagulated whole blood was simultaneously collected for REBA Sepsis-ID and blood culture from 440 patients with suspected sepsis, from January to October 2015. In addition, CRP and PCT concentrations were measured in 227 patients. The overall positive rates of REBA Sepsis-ID and blood culture were 16.6% (73/440) and 13.9% (61/440), respectively. The pathogen-positive rates of REBA Sepsis-ID and blood culture were 9.8% (43/440) and 9.5% (42/440), respectively. The areas under the receiver operating characteristic (AUROC) curves of PCT and CRP for predicting pathogen-positive results of REBA Sepsis-ID were 0.72 and 0.69, respectively. The PCT concentrations in the group of patients aged ≥50 years were significantly higher than those in the group aged <50 years. After adjusting for age, the PCT AUROC value was 0.77 for predicting pathogen-positive results of REBA Sepsis-ID. The optimal cutoff values of PCT concentrations for subsequent application of REBA Sepsis-ID were 0.12 ng/mL in all patients and 0.22 ng/mL in patients aged ≥50 years. Our observations showed that REBA Sepsis-ID using whole blood was advantageous for the early detection of sepsis-causing microorganisms, and the PCT concentration could be used to determine the necessity of using REBA Sepsis-ID in clinical settings. The application of REBA Sepsis-ID using whole blood, based on the PCT concentration, may contribute to a highly efficient detection of sepsis-causing microorganisms.

Ecology of Bloodstream Infections and Temporal Trends of Their Antibiograms with Respect to Source and Duration of Incubation: A 5-Year Retrospective Observational Analysis

Purpose  Blood is one of the most important connective tissues of human body. Bloodstream infection can range from inapparent bacteremia till fulminant septic shock with high mortality. Presence of microbes in blood whether continuously, intermittently, or transiently is a grave risk to every organ of body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. Objective  The aim of the study is to perform bacteriological analysis and assess drug sensitivity patterns of blood culture isolates and compare in light of other associated variables. Design  Retrospective observational study was conducted from January 2009 to December 2013 at a tertiary care hospital at Shillong, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified by standard biochemical tests and subjected to sensitivity testing according to Modified Kirby Bauer disk diffusion method. Data for source of blood collection and duration of incubation were noted and compared. Results  A total of 658 (11.2%) pathogens were isolated from 5,867 bacteremia-suspected patient blood specimens. Contamination was observed at the rate of 1.21%. Gram-negative organisms were the predominant pathogens recovered, Klebsiella pneumoniae being the most common. No significant difference was observed between the number of organisms isolated within or beyond 48 hours. Acinetobacter baumannii and K. pneumoniae have significantly higher chances ( p < 0.05) of isolation from central line catheters compared with peripheral venipuncture. Conclusion  Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.

Development of Solid-Phase RPA on a Lateral Flow Device for the Detection of Pathogens Related to Sepsis

Population extended life expectancy has significantly increased the risk of septic shock in an ageing population. Sepsis affects roughly 20 million people every year, resulting in over 11 million deaths. The need for faster more accurate diagnostics and better management is therefore paramount in the fight to prevent these avoidable deaths. Here we report the development of a POC device with the ability to identify a broad range of pathogens on a lateral flow platform. Namely Gram-positive and Gram-negative bacteria. The simple to use laboratory device has the potential to be automated, thus enabling an operator to carry out solid-phase lysis and room temperature RPA in situ, providing accurate results in hours rather than days. Results show there is a potential for a fully automated device in which concepts described in this paper can be integrated into a lateral flow device.

C-Reactive Protein Concentration Can Help to Identify Bacteremia in Children Visiting the Emergency Department: A Single Medical Center Experience

BACKGROUND

For febrile children who are evaluated in a pediatric emergency department (PED), blood culture can be considered the laboratory criterion standard to detect bacteremia. However, high rates of negative, false-positive, or contaminated blood cultures in children often result in this testing being noncontributory. This study determined the factors associated with true-positive blood cultures in children.

METHODS

This retrospective study was conducted at a tertiary medical center's PED. The blood culture use reports were prepared by an infectious disease specialist and were classified as bacteremia, nonbacteremia, and contamination.

RESULTS

We registered a total of 239,459 PED visits during the 8-year period, and 21,841 blood culture samples were taken. Of the laboratory test studies, higher C-reactive protein (CRP) levels and lower hemoglobin levels were observed in the bacteremia group compared with other groups (all P < 0.001). The cut-off value calculated for each age group was adjusted for better clinical usage and significantly improved the blood culture clinical utility documented in the following age groups: 0 to 1 years (CRP level = 30 mg/L, odds ratio [OR] = 5.4, P < 0.001), 1 to 3 years (CRP level = 45 mg/L, OR = 3.7, P < 0.001), and 12 to 18 years (CRP level = 50 mg/L, OR = 6.3, P = 0.006). Using the CRP cut-off value established in this study, we could reduce the blood culture samples in the PED by 14,108 (64.6%).

CONCLUSIONS

This study provides new evidence that CRP may be a useful indicator for blood culture sampling in certain age groups and may help improve the efficiency of blood culture in the PED.

Reducing Blood Culture Contamination Rates: Experiences of Four Hospital Systems

INTRODUCTION

Blood cultures (BCs) frequently become contaminated during the pre-analytic phase of collection leading to downstream ramifications. We present a summary of performance improvement (PI) interventions provided by four hospital systems and common factors that contributed to decreased blood culture contamination (BCC) rates.

METHODS

Each hospital independently formed a multidisciplinary team and action plan for implementation of their intervention, focusing on the use of educational and training tools. Their goal was to significantly decrease their BCC rates. Pre- and post-intervention data were compared during the sustainment period to determine their success.

RESULTS

All hospitals met their goals of post-intervention BCC rates and with most achieving and sustaining BCC rates ≤ 1.0-2.0%.

CONCLUSION

Our report highlights how four hospitals independently achieved their objective to decrease their BCC rate with the support of a multidisciplinary team. We propose a benchmark for BCC rates of 1.5 to < 2.0% as achievable and sustainable.

Using Machine Learning to Predict Bacteremia in Febrile Children Presented to the Emergency Department

Blood culture is frequently used to detect bacteremia in febrile children. However, a high rate of negative or false-positive blood culture results is common at the pediatric emergency department (PED). The aim of this study was to use machine learning to build a model that could predict bacteremia in febrile children. We conducted a retrospective case-control study of febrile children who presented to the PED from 2008 to 2015. We adopted machine learning methods and cost-sensitive learning to establish a predictive model of bacteremia. We enrolled 16,967 febrile children with blood culture tests during the eight-year study period. Only 146 febrile children had true bacteremia, and more than 99% of febrile children had a contaminant or negative blood culture result. The maximum area under the curve of logistic regression and support vector machines to predict bacteremia were 0.768 and 0.832, respectively. Using the predictive model, we can categorize febrile children by risk value into five classes. Class 5 had the highest probability of having bacteremia, while class 1 had no risk. Obtaining blood cultures in febrile children at the PED rarely identifies a causative pathogen. Prediction models can help physicians determine whether patients have bacteremia and may reduce unnecessary expenses.

Enhanced Performance of Next-Generation Sequencing Diagnostics Compared With Standard of Care Microbiological Diagnostics in Patients Suffering From Septic Shock

Supplemental Digital Content is available in the text.

Objectives:

Culture-based diagnostics represent the standard of care in septic patients, but are highly insensitive and in many cases unspecific. We recently demonstrated the general feasibility of next-generation sequencing-based diagnostics using free circulating nucleic acids (cell-free DNA) in plasma samples of septic patients. Within the presented investigation, higher performance of next-generation sequencing-based diagnostics was validated by comparison to matched blood cultures.

Design:

A secondary analysis of a prospective, observational, single-center study.

Setting:

Surgical ICU of a university hospital and research laboratory.

Patients:

Fifty patients with septic shock, 20 uninfected patients with elective surgery as control cohort.

Interventions:

None.

Measurements and Main Results:

From 256 plasma samples of 48 septic patients at up to seven consecutive time points within the 28-day observation period, cell-free DNA was isolated and analyzed by next-generation sequencing and relevance scoring. In parallel, results from culture-based diagnostics (e.g., blood culture) were obtained. Plausibility of blood culture and next-generation sequencing results as well as adequacy of antibiotic therapy was evaluated by an independent expert panel. In contrast to blood culture with a positivity rate of 33% at sepsis onset, the positivity rate for next-generation sequencing-based pathogen identification was 72%. Over the whole study period, blood culture positivity was 11%, and next-generation sequencing positivity was 71%. Ninety-six percent of positive next-generation sequencing results for acute sepsis time points were plausible and would have led to a change to a more adequate therapy in 53% of cases as assessed by the expert evaluation.

Conclusions:

Our results show that next-generation sequencing-based analyses of bloodstream infections provide a valuable diagnostic platform for the identification of clinically relevant pathogens with higher sensitivity and specificity than blood culture, indicating that patients might benefit from a more appropriate therapy based on next-generation sequencing-based diagnosis.

Inpatient Management of Uncomplicated Skin and Soft Tissue Infections in 34 Veterans Affairs Medical Centers: A Medication Use Evaluation

BACKGROUND

Skin and soft tissue infections (SSTIs) are a key antimicrobial stewardship target because they are a common infection in hospitalized patients, and non-guideline-concordant antibiotic use is frequent. To inform antimicrobial stewardship interventions, we evaluated the proportion of veterans hospitalized with SSTIs who received guideline-concordant empiric antibiotics or an appropriate total duration of antibiotics.

METHODS

A retrospective medication use evaluation was performed in 34 Veterans Affairs Medical Centers between 2016 and 2017. Hospitalized patients who received antibiotics for uncomplicated SSTI were included. Exclusion criteria were complicated SSTI, severe immunosuppression, and antibiotics for any non-SSTI indication. Data were collected by manual chart review. The primary outcome was the proportion of patients receiving both guideline-concordant empiric antibiotics and appropriate treatment duration, defined as 5-10 days of antibiotics. Data were analyzed and reported using descriptive statistics.

RESULTS

Of the 3890 patients manually evaluated for inclusion, 1828 patients met inclusion criteria. There were 1299 nonpurulent (71%) and 529 purulent SSTIs (29%). Overall, 250 patients (14%) received guideline-concordant empiric therapy and an appropriate duration. The most common reason for non-guideline-concordance was receipt of antibiotics targeting methicillin-resistant Staphylococcus aureus (MRSA) in 906 patients (70%) with a nonpurulent SSTI. Additionally, 819 patients (45%) received broad-spectrum Gram-negative coverage, and 860 patients (48%) received an antibiotic duration >10 days.

CONCLUSIONS

We identified 3 common opportunities to improve antibiotic use for patients hospitalized with uncomplicated SSTIs: use of anti-MRSA antibiotics in patients with nonpurulent SSTIs, use of broad-spectrum Gram-negative antibiotics, and prolonged durations of therapy.

Time to blood cultures positivity of microorganisms using a continuous-monitoring automated blood cultures system

Background

Previous studies showed that clinically significant pathogens were detected within 3 days of incubation using a continuous monitoring automated blood culture instrument.

Objectives

To determine time to blood culture positivity (TTP) of microorganisms using a BD BACTEC™ FX.

Methods

A cross-sectional study was conducted at Maharaj Nakorn Chiang Mai Hospital, Thailand from October to November 2014.

Results

One-hundred and eighty-one patients with 195 episodes of infection and 436 cultures were included in the analysis. Among 181 patients, 55.2% were male and the median age was 61 years (interquartile range (IQR) 50, 76). Of the 195 episodes of infections, the most common source was genitourinary tract (15.4%). Overall, the median TTP was 17 hours (IQR 11.5, 24.5), the shortest TTP was observed in Streptococcus agalactiae. Four-hundred and seventy-eight cultures (97.6%) and all (100%) were detected at 3 days and 5 days of incubation. Factors associated with TTP ≤24 hour were blood drawn from patients who had hematologic malignancy (odds ratio (OR) 9.6, 95% confidence interval (CI) 1.2, 74.3, P = 0.030), endocarditis and vascular infection (OR 8.7, 95% CI 1.1, 67.2, P = 0.038), thrombocytopenia (OR 2.4, 95% CI 1.3, 4.4, P = 0.004), clinical of systemic inflammatory response syndrome (SIRS) (OR 2.3, 95% CI 1.2, 4.5, P = 0.014), and not receiving antimicrobials within 72 hours before cultures taken (OR 2.2, 95% CI 1.4, 3.6, P < 0.001).

Conclusions

TTP varied depends upon the pathogens and clinical settings. However, bacteria were isolated from almost, but not all of the blood cultures within 3 days of incubation.

Practical Guidance for Clinical Microbiology Laboratories: A Comprehensive Update on the Problem of Blood Culture Contamination and a Discussion of Methods for Addressing the Problem

In this review, we present a comprehensive discussion of matters related to the problem of blood culture contamination. Issues addressed include the scope and magnitude of the problem, the bacteria most often recognized as contaminants, the impact of blood culture contamination on clinical microbiology laboratory function, the economic and clinical ramifications of contamination, and, perhaps most importantly, a systematic discussion of solutions to the problem. We conclude by providing a series of unanswered questions that pertain to this important issue.

Successful Reduction of Blood Culture Contamination in an Emergency Department by Monitoring and Feedback

Background:

Blood Culture (BC) contamination is a common problem in the Emergency Department (ED) and is associated with prolonged length of patient stay and excess costs.

Objective:

The study aimed to investigate the impact of monthly monitoring and feedback of BC results on contamination rates.

Methods:

Data from a previous study showed that the contamination rate in the ED consistently exceeded the recommended level. This triggered an ad hoc Quality Improvement team to develop and implement a corrective action plan. In 2017, BC contamination rates were reported to the ED on a monthly basis. In response to this, ED staff conducted intensified educational workshops, followed by private counselling and competency assessment of nurses who collected contaminated BCs.

Results:

A total of 12 educational workshops were conducted in February and March, 2017. The intervention resulted in >60% reduction in the contamination rate, from 8.6% baseline level to less than 3%. Of the 2660 BC sets drawn in 2017 from 1318 patients, 128 (4.8%) were contaminated, accounting for 39.5% of the total number of positive cultures. Sixty percent of the contaminated BCs grew Coagulase-negativeStaphylococcusspecies; other contaminants includedCorynebacteriumspp.,Micrococcusspp.,Propionibacteriumspp.,viridansStreptococcus, andNeisseriaspp.

Conclusion:

Continuous monitoring and feedback of contamination rates reduced BC contamination.

Clinical experience in management of bloodstream infection in emergency medical ward: A preliminary report

Background:

Bloodstream infection is a life-threatening clinical condition posing significant morbidities and mortalities. An “Emergency Critical Care Management Program” has been implemented in the Emergency Medicine Ward at North Lantau Hospital as a pilot critical care service model in the local emergency medicine wards. Patients with blood stream infection are recruited in the program and managed under pre-defined guideline.

Objectives:

We report our experience in managing patients with blood stream infection in the Emergency Medicine Ward and analyzed their clinical outcomes.

Methods:

This was a retrospective cohort study including a total of 64 patients with blood stream infection admitted to the Emergency Medicine Ward from 1 March 2015 and 31 March 2018. Patients’ characteristics, microbiology, and risk factors associated with adverse outcomes including in-hospital mortality were analyzed.

Results:

The most common organism isolated from blood cultures was Escherichia coli (56%). Eight patients were transferred to the tertiary hospital. The overall in-hospital mortality was 7.8% (5/64). From the univariate analysis, advanced age (p < 0.001), higher Sequential Organ Failure Assessment score and quick Sequential Organ Failure Assessment score (p < 0.001), higher Charlson Comorbidity Index (p = 0.003), more organ dysfunction (p < 0.001), pre-existing medical history of chronic liver disease (p = 0.001), dysfunction in respiratory system (p = 0.032), cardiovascular system (p = 0.044) and the central nervous system (p < 0.001), presence of septic shock (p = 0.004), and need for higher level of organ support from the use of inotropes (p < 0.001) and mechanical ventilation (p = 0.024) were associated with in-hospital mortality. In the subgroup analysis, the in-hospital mortality rate for the patients with Sequential Organ Failure Assessment score less than 6 was 1.56% (1/64). Among the five in-hospital mortality cases, four of them were managed in the Emergency Medicine Ward under the End-of-Life Care Program. Decision for withholding and withdrawing life-sustaining therapy was made with the patients’ families.

Conclusion:

This preliminary report demonstrated that with careful patient selection, adoption of guidelines, and availability of expertise, critical care service can be safely implemented in the emergency medicine ward.

Clinical Significance of Isolates Known to Be Blood Culture Contaminants in Pediatric Patients

Background and objectives: The objective of this study was to investigate the clinical significance of isolates from blood stream infection known to be blood culture contaminants in pediatric patients. Materials and Methods: Microbiological reports and medical records of all blood culture tests issued from 2002 to 2012 (n = 76,331) were retrospectively reviewed. Evaluation for potential contaminants were done by reviewing medical records of patients with the following isolates: coagulase-negative Staphylococcus, viridans group Streptococcus, Bacillus, Corynebacterium, Micrococcus, Aerococcus, and Proprionibacterium species. Repeated cultures with same isolates were considered as a single case. Cases were evaluated for their status as a pathogen. Results: Coagulase-negative Staphylococcus had clinical significance in 23.8% of all cases. Its rate of being a true pathogen was particularly high in patients with malignancy (43.7%). Viridans group Streptococcus showed clinical significance in 46.2% of all cases. Its rate of being a true pathogen was similar regardless of the underlying morbidity of the patient. The rate of being a true pathogens for remaining isolates was 27.7% for Bacillus and 19.0% for Corynebacterium species. Conclusions: Coagulase-negative Staphylococcus and viridans group Streptococcus isolates showed high probability of being true pathogens in the pediatric population, especially in patients with underlying malignancy.