Use of flow cytometry method to detect contaminations of platelet suspensions.

In this study, it was aimed to investigate bacterial contamination in apheresis platelet suspensions (APS) by automated blood culture system and flow cytometry method (FCM).33 spiked APS each using 11 bacterial strains (5 standard strains, 6 clinical isolates), were prepared in three different dilutions (1-10, 10-50, 50-100 cfu/mL), incubated in two different temperatures (35-37 °C and 22-24 °C) and different incubation times (18-96 h) evaluated by FCM. This three different dilutions were also inoculated into special platelet culture bottles (BacT/ALERT® BPA) and loaded into the blood culture system. Additionally 80 APSs routinely prepared in the Transfusion Center were evaluated by both FCM and the blood culture system. Platelets were lysed by freeze-thaw method.All spiked samples were positive with BacT/ALERT® BPA in 12-18 h. In 96 h incubation at 22-24 °C, the presence of bacteria was detected by FCM in all other samples (31/33) except low dilutions (1-10 and 10-100 CFU/ml) of K.pneumoniae standard strain. In the 35-37 °C, the presence of bacteria was detected by FCM in all samples (33/33) after 48 h of incubation. In routine APS one sample detected as positive (Bacillus simplex) with BacT/ALERT® BPA and no positivity was detected by FCM.The freeze-thaw method, which we have optimized for the lysis of platelets, is very practical and can be easily applied. The BacT/ALERT® system has been found to be very sensitive in detecting bacterial contamination in PSs. Flow cytometry method has been found to be successful, fast, easy to use and low cost in detecting bacterial contamination in PSs.

An emergency department intervention to improve earlier detection of community-onset bloodstream infection among hospitalized patients.

BACKGROUND: Blood cultures (BCs) are essential microbiologic tests, but blood culturing diagnostic stewardship is frequently poor. We aimed to study the process-related failures and to evaluate the effect of an emergency department (ED) intervention on BCs collection practices and yield. METHODS: We implemented an ED-quality improvement intervention including educational sessions, phlebotomists addition, promoting single-site strategy for BC-collection and preanalytical data feedback. BC-bottles collected, positive BCs, blood volumes and documentation of collection times were measured, before (December 2021-August 2022) and after (September 2022-July 2023) intervention. Results were corrected to hospitalizations admissions or days. We used interrupted-time series analyses for comparisons. RESULTS: A total of 64,295 BC bottles were evaluated, 26,261 before and 38,034 postintervention. The median ED-BCs collected per week increased from 88 to 105 BCs (P < .0001), resulting from increased early sampling (P = .0001). Solitary BCs decreased (95%-28%), documented times increased (2.8%-25%), and average blood volume increased (3 mL to 4.5 mL) postintervention. Community-onset Bloodstream infections (BSIs) increased (39.6-52 bottles/1,000 admissions, P = .0001), while Health care-associated BSIs decreased (39-27 bottles/10,000 days, P = .0042). Contamination rates did not change. CONCLUSIONS: An ED-focused intervention based on the education sessions and single-site strategy improved culturing stewardship and facilitated the early identification of BSI without an increase in contamination.

Blood culture contamination in the departments of paediatrics and child health at two tertiary training hospitals in central South Africa.

BACKGROUND: Bloodstream infections are an important cause of mortality in children. Blood cultures (BCs) remain the primary means of identifying organisms and their antibiotic susceptibility profiles. A shortcoming of BCs is that up to 56% of positive cultures will represent contaminants. Poor adherence to standard practices applicable to BC sampling could explain an unacceptable contamination rate. OBJECTIVES: To determine: (i) the BC contamination rate in the departments of paediatrics and child health at two tertiary hospitals in central South Africa; and (ii) BC sampling practices among paediatric clinicians. METHODS: The author determined the prevalence of BC contamination by analysis of laboratory data for the period 1 May - 27 August 2019, and assessed possible factors contributing to BC contamination by surveying paediatric medical staff with a self-administered BC practices questionnaire. RESULTS: Of the 244 BCs reviewed, 25.4% were positive. The most commonly isolated pathogens were coagulase-negative staphylococci (CoNS) (33.3%), Escherichia coli (22.2%), Enterococcus faecium (16.7%) and Acinetobacter baumannii (11.1%). In total, 15.2% of the BCs yielded contaminants and 2.9% had polymicrobial growth. The most common contaminant was CoNS. Approximately 68% of clinicians were not aware of BC sampling guidelines, and even among those who were aware of the guidelines, non-compliance was reported. CONCLUSIONS: The BC contamination rate was higher than internationally accepted rates. Educating clinicians on specific BC sampling guidelines is strongly recommended to decrease the high rate of contamination observed in this study.

Comparison of novel rapid diagnostic of blood culture identification and antimicrobial susceptibility testing by Accelerate Pheno system and BioFire FilmArray Blood Culture Identification and BioFire FilmArray Blood Culture Identification 2 panels.

BACKGROUND: Conventional turnaround time (TAT) for positive blood culture (PBC) identification (ID) and antimicrobial susceptibility testing (AST) is 2-3 days. We evaluated the TAT and ID/AST performance using clinical and seeded samples directly from PBC bottles with different commercial approaches: (1) Accelerate Pheno® system (Pheno) for ID/AST; (2) BioFire® FilmArray® Blood Culture Identification (BCID) Panel and/ or BCID2 for ID; (3) direct AST by VITEK® 2 (direct AST); and (4) overnight culture using VITEK® 2 colony AST. RESULTS: A total of 141 PBC samples were included in this evaluation. Using MALDI-TOF (Bruker MALDI Biotyper) as the reference method for ID, the overall monomicrobial ID sensitivity/specificity are as follows: Pheno 97.9/99.9%; BCID 100/100%; and BCID2 100/100%, respectively. For AST performance, broth microdilution (BMD) was used as the reference method. For gram-negatives, overall categorical and essential agreements (CA/EA) for each method were: Pheno 90.3/93.2%; direct AST 92.6/88.5%; colony AST 94.4/89.5%, respectively. For gram-positives, the overall CA/EAs were as follows: Pheno 97.2/98.89%; direct AST 97.2/100%; colony AST 97.2/100%, respectively. The BCID/BCID2 and direct AST TATs were around 9-20 h (1/9-19 h for ID with resistance markers/AST), with 15 min/sample hands-on time. In comparison, Pheno TATs were around 8-10 h (1.5/7 h for ID/AST) with 2 min/sample hands-on time, maintains a clinically relevant fast report of antibiotic minimal inhibitory concentration (MIC) and allows for less TAT and hands-on time. CONCLUSION: In conclusion, to the best of our knowledge, this is the first study conducted as such in Asia; all studied approaches achieved satisfactory performance, factors such as TAT, panel of antibiotics choices and hands-on time should be considered for the selection of appropriate rapid ID and AST of PBC methods in different laboratory settings.

Underutilization and Quality Gaps in Blood Culture Processing in Public Hospitals of Peru.

Correct processing of blood cultures may impact individual patient management, antibiotic stewardship, and scaling up of antimicrobial resistance surveillance. To assess the quality of blood culture processing, we conducted four assessments at 16 public hospitals across different regions of Peru. We assessed the following standardized quality indicators: 1) positivity and contamination rates, 2) compliance with recommended number of bottles/sets and volume of blood sampled, 3) blood culture utilization, and 4) possible barriers for compliance with recommendations. Suboptimal performance was found, with a median contamination rate of 4.2% (range 0-15.1%), with only one third of the participating hospitals meeting the target value of < 3%; and a median positivity rate of 4.9% (range 1-8.1%), with only 6 out of the 15 surveilled hospitals meeting the target of 6-12%. None of the assessed hospitals met both targets. The median frequency of solitary blood cultures was 71.9% and only 8.9% (N = 59) of the surveyed adult bottles met the target blood volume of 8 - 12 mL, whereas 90.5% (N = 602) were underfilled. A high frequency of missed opportunities for ordering blood cultures was found (69.9%, 221/316) among patients with clinical indications for blood culture sampling. This multicenter study demonstrates important shortcomings in the quality of blood culture processing in public hospitals of Peru. It provides a national benchmark of blood culture utilization and quality indicators that can be used to monitor future quality improvement studies and diagnostic stewardship policies.

Diagnostic yield of routine daily blood culture in patients on veno-arterial extracorporeal membrane oxygenation.

BACKGROUND: Bloodstream infections (BSIs) are frequent on veno-arterial extracorporeal membrane oxygenation (V-A ECMO). Performing routine blood cultures (BCs) may identify early paucisymptomatic BSIs. We investigated the contribution of systematic daily BCs to detect BSIs on V-A ECMO. METHODS: This was a retrospective study including all adult patients requiring V-A ECMO and surviving more than 24 h. Our protocol included routine daily BCs, from V-A ECMO insertion up to 5 days after withdrawal; other BCs were performed on-demand. RESULTS: On the 150 V-A ECMO included, 2146 BCs were performed (1162 routine and 984 on-demand BCs); 190 (9%) were positive, including 68 contaminants. Fifty-one (4%) routine BCs revealed BSIs; meanwhile, 71 (7%) on-demand BCs revealed BSIs (p = 0.005). Performing routine BCs was negatively associated with BSIs diagnosis (OR 0.55, 95% CI [0.38; 0.81], p = 0.002). However, 16 (31%) BSIs diagnosed by routine BCs would have been missed by on-demand BCs. Independent variables for BSIs diagnosis after routine BCs were: V-A ECMO for cardiac graft failure (OR 2.43, 95% CI [1.20; 4.92], p = 0.013) and sampling with on-going antimicrobial therapy (OR 2.15, 95% CI [1.08; 4.27], p = 0.029) or renal replacement therapy (OR 2.05, 95% CI [1.10; 3.81], p = 0.008). Without these three conditions, only two BSIs diagnosed with routine BCs would have been missed by on-demand BCs sampling. CONCLUSIONS: Although routine daily BCs are less effective than on-demand BCs and expose to contamination and inappropriate antimicrobial therapy, a policy restricted to on-demand BCs would omit a significant proportion of BSIs. This argues for a tailored approach to routine daily BCs on V-A ECMO, based on risk factors for positivity.

Time to positivity as a prognostic factor in bloodstream infections with Enterococcus spp.

Time to positivity (TTP) is the delay of time from incubation to blood culture positivity. Short TTP can predict mortality and source of infection. The aim of this study was to investigate the value of TTP of patients with bloodstream infections with enterococci (E-BSI).In a single centre retrospective cohort study in Germany, the data of 244 patients with monomicrobial E-BSI were analyzed with hospital mortality as the primary outcome of interest from January 1 2014 to December 31 2016. Mortality rate of patients with bloodstream infections (BSI) with E. faecalis was 16.7%, Vancomycin sensitive E. faecium (VSEfm) 26.7% and Vancomycin resistant E. faecium (VREfm) 38.2%. Cut-offs showed a significantly higher mortality rate when compared to longer TTP (E. faecalis: P=0.047; VSEfm: P=0.02), but were not risk factors in survival analysis (E.faecalis: HR (hazard ratio): 2.73; P=0.17; VSEfm: HR: 1.63; P=0.15; VREfm: HR: 1.24; P=0.63). TTP≤10.5 hours with E. faecalis BSI was a discriminator for cardiovascular source of infection (AUC: 0.75). A short TTP could predict mortality rates and source of infection but was not an independent parameter for risk of death in survival analysis.

Evaluation of a Novel Culture System for Rapid Pathogen Identification and Detection of Cephalosporin Resistance in Neonatal Gram-negative Sepsis at a Tertiary Referral Unit in Harare, Zimbabwe.

BACKGROUND: Neonatal sepsis accounts for a large proportion of neonatal deaths in sub-Saharan Africa. The lack of access to diagnostic testing and excessively long turnaround times to result contributes to delays in sepsis identification and initiation of appropriate treatment. This study aims to evaluate the novel InTrays COLOREX Screen and extended-spectrum beta-lactamase for rapid identification of bacterial pathogens causing sepsis and detection of resistance. METHODS: Neonates with suspected sepsis admitted to the Harare Central Hospital were prospectively enrolled. One blood culture was collected and incubated using the BacT/ALERT automated system. Positive blood cultures with potential pathogens identified by Gram stain were inoculated on the InTray COLOREX Screen and extended-spectrum beta-lactamase culture plates. RESULTS: A total of 216 neonates with suspected sepsis were recruited. Pathogens were isolated from blood cultures in 56 (25.9%) neonates of which 54 were Klebsiella pneumoniae. All K. pneumoniae were resistant to ceftriaxone and 53 (98%) were resistant to gentamicin. Sensitivity and specificity for ceftriaxone-resistant K. pneumoniae detection using InTrays were 100%. InTrays results were interpretable as early as 5-10 hours (median 7 hours, interquartile range 7-7) post blood culture positivity enabling rapid identification and notification of result and leading to a 60% reduction in time to result from blood culture collection. CONCLUSIONS: This study shows that the implementation of a novel culture method was feasible and reduced turnaround times for results by 60% compared with standard microbiologic techniques. An impact on patient outcomes and cost-effectiveness of this method needs to be demonstrated.

Comparison of novel approaches for expedited pathogen identification and antimicrobial susceptibility testing against routine blood culture diagnostics.

Blood stream infections pose a major challenge for clinicians as the immediate application of an appropriate antibiotic treatment is the vital factor to safe the patients' lives. This preliminary study compares three different systems promising fast pathogen identification and susceptibility testing in comparison to conventional blood culture (BC): (i) the rapid antimicrobial susceptibility testing protocol according to EUCAST in combination with the Sepsityper® kit (sRAST), (ii) the direct inoculation method on the VITEK® 2 system (dVIT) and (iii) testing with the Accelerate Pheno® system (AccPh). All methods were assessed in terms of accuracy, time to result and usability. Twenty-three BC samples obtained from patients suffering from proven sepsis were analysed in detail. Pathogen identification was successful in 95·6, 91·3 and 91·3% in sRAST, dVIT and AccPh, respectively. Categorical agreement in antimicrobial susceptibility testing was 89·5, 96 and 96·6%, respectively. Time to result from sample entry to reporting ranged from an average of 4·6 h for sRAST and 6·9 h for AccPh to 10·6 h for dVIT. These results imply a significant shortening of reporting times at considerably high agreement rates for these new diagnostic approaches.

Turkish pediatric residents' knowledge, perceptions, and practices of blood culture sampling.

INTRODUCTION: Pediatrics is one of the medical specialties in which blood cultures for bloodstream infections are performed very frequently. This study aimed to evaluate pediatric residents' knowledge and perceptions of blood culture sampling. MATERIAL AND METHODS: Between June 2019 and September 2019, a questionnaire comprising 20 questions about blood culture sampling was sent via email to participants who were pediatric residents at five different hospitals in Turkey. There were 11 true/false and nine multiple-choice questions that assessed three aspects of culture sampling: indications, sampling practice and knowledge, and contamination. The percentage of correct answers was used to calculate an overall score and subsection scores. RESULTS: A total of 132 pediatric residents [102 (77%) female] with a mean age of 28.3±2.8 years completed the questionnaire. Forty-five (35%) were in their 1st year of residency. Sixty (46%) participants reported that they had not performed blood culture sampling in the last week. There was a negative relationship between years in training and the number of cultures performed (Kendal's tau-b=-0.297, p<0.001). The overall median score was 65 (range, 35-90) and it seemed to increase with years of training. The lowest median score was in the contamination subscale and only one (0.76%) participant correctly answered all questions concerning contamination. CONCLUSION: Residents who obtained the majority of blood cultures had the lowest knowledge levels. Therefore, it is evident that the knowledge levels of pediatric residents must be increased in order to improve blood culture sampling practices in centers where they perform blood culture sampling.

Impact of delays to incubation and storage temperature on blood culture results: a multi-centre study.

BACKGROUND: Blood cultures are one of the most important tests performed by microbiology laboratories. Many hospitals, particularly in low and middle-income countries, lack either microbiology services or staff to provide 24 h services resulting in delays to blood culture incubation. There is insufficient guidance on how to transport/store blood cultures if delays before incubation are unavoidable, particularly if ambient temperatures are high. This study set out to address this knowledge gap. METHODS: In three South East Asian countries, four different blood culture systems (two manual and two automated) were used to test blood cultures spiked with five common bacterial pathogens. Prior to incubation the spiked blood culture bottles were stored at different temperatures (25 °C, in a cool-box at ambient temperature, or at 40 °C) for different lengths of time (0 h, 6 h, 12 h or 24 h). The impacts of these different storage conditions on positive blood culture yield and on time to positivity were examined. RESULTS: There was no significant loss in yield when blood cultures were stored < 24 h at 25 °C, however, storage for 24 h at 40 °C decreased yields and longer storage times increased times to detection. CONCLUSION: Blood cultures should be incubated with minimal delay to maximize pathogen recovery and timely result reporting, however, this study provides some reassurance that unavoidable delays can be managed to minimize negative impacts. If delays to incubation ≥ 12 h are unavoidable, transportation at a temperature not exceeding 25 °C, and blind sub-cultures prior to incubation should be considered.

Asynchronous Testing of 2 Specimen-Diversion Devices to Reduce Blood Culture Contamination: A Single-Site Product Supply Quality Improvement Project.

OBJECTIVE: Blood culture contamination above the national threshold has been a consistent clinical issue in the ED setting. Two commercially available devices were examined that divert an initial small volume of the specimen before the collection of blood culture to reduce skin contamination. METHODS: Prospectively, 2 different blood culture-diversion devices were made available in the unit supplies to ED clinicians at a single site during 2 different periods of time as a follow-up strategy to an ongoing quality improvement project. Blood samples were collected in the emergency department over a period of 16 months. A retrospective record review study was conducted comparing the use of the 2 specimen-diversion devices with no device (control group) for blood culture contamination rates. The main outcome of monthly blood culture contamination per device was tested using a Bayesian Poisson multilevel regression model. RESULTS: A total of 4030 blood samples were collected and analyzed from November 2017 to February 2019. The model estimated that the mean incidence of contaminated blood draws in the device A group was 0.29 (0.14-0.55) times the incidence of contaminated draws in the control group. The mean incidence of contaminated blood draws in the device B group was 0.23 (0.13-0.37) times the incidence of contaminated draws in the control group, suggesting that initial-diversion methods reduced blood culture contamination. CONCLUSION: Initial specimen-diversion devices supplement present standard phlebotomy protocols to bring down the blood culture contamination rate.

Opportunities to Improve Antibiotic Prescribing in Outpatient Hemodialysis Facilities: A Report From the American Society of Nephrology and Centers for Disease Control and Prevention Antibiotic Stewardship White Paper Writing Group.

Antibiotic use is necessary in the outpatient hemodialysis setting because patients receiving hemodialysis are at increased risk for infections and sepsis. However, inappropriate antibiotic use can lead to adverse drug events, including adverse drug reactions and infections with Clostridioides difficile and antibiotic-resistant bacteria. Optimizing antibiotic use can decrease adverse events and improve infection cure rates and patient outcomes. The American Society of Nephrology and the US Centers for Disease Control and Prevention created the Antibiotic Stewardship in Hemodialysis White Paper Writing Group, comprising experts in antibiotic stewardship, infectious diseases, nephrology, and public health, to highlight strategies that can improve antibiotic prescribing for patients receiving maintenance hemodialysis. Based on existing evidence and the unique patient and clinical setting characteristics, the following strategies for improving antibiotic use are reviewed: expanding infection and sepsis prevention activities, standardizing blood culture collection processes, treating methicillin-susceptible Staphylococcus aureus infections with ß-lactams, optimizing communication between nurses and prescribing providers, and improving data sharing across transitions of care. Collaboration among the Centers for Disease Control and Prevention; American Society of Nephrology; other professional societies such as infectious diseases, hospital medicine, and vascular surgery societies; and dialysis provider organizations can improve antibiotic use and the quality of care for patients receiving maintenance hemodialysis.

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.

Nonautomated Blood Cultures in a Low-Resource Setting: Optimizing the Timing of Blind Subculture.

Laboratory procedures for blood cultures in a hospital in Phnom Penh were adapted to optimize detection of Burkholderia pseudomallei, an important pathogen in this setting. The effects of these changes are analyzed in this study. Blood cultures consisted of two BacT/ALERT bottles (bioMérieux, Marcy-l'Etoile, France). Growth was detected visually by daily inspection of the bottles. In 2016, the aerobic-anaerobic pair (FA/FN FAN) was substituted by an aerobic pair of BacT/ALERT FA Plus bottles. Blind subculture (BS) (subculture in the absence of visual growth) was advanced from day 3 to day 2 of incubation in July 2016. In July 2018, it was further advanced to day 1 of incubation. From July 2016 to October 2019, 9,760 blood cultures were sampled. The proportion of cultures showing pathogen growth decreased from 9.6% to 6.8% after the implementation of the laboratory changes (P < 0.001). Advancing the BS from day 3 to day 2 led to an increased proportion of pathogens detected by day 3 (92.8% versus 82.3%; P < 0.001); for B. pseudomallei, this increase was even more remarkable (92.0% versus 18.2%). Blind subculture on day 1 similarly increased the proportion of pathogens detected by day 2 (82.9% versus 69.0% overall, 66.7% versus 10.0% for B. pseudomallei; both P < 0.001). However, after implementation of day 1 subculture, a decrease in recovery of B. pseudomallei was observed (12.4% of all pathogens versus 4.3%; P < 0.001). In conclusion, earlier subculture significantly shortens time to detection and time to actionable results. Some organisms may be missed by performing an early subculture, especially those that grow more slowly.

False-positive blood cultures: The need for follow-up.

The diagnosis of blood-borne infections in immunocompromised patients is a major challenge for the clinical microbiology laboratory. Isolation of bloodborne pathogens in these patients has profound clinical implications, yet is fraught with technical problems, including the presence of unusual and difficult to isolate pathogens. Coupled with this is the problem of false-positive blood culture signals from automated blood culture systems which further delays the definitive diagnosis. Here, we present a case of an 8-year-old boy with Ph +ve acute lymphoblastic leukaemia who has repeated 'false positive' blood cultures and later grew an uncommon organism.

Comparison of Rapid and Routine Methods of Identification and Antibiotic Susceptibility Testing of Microorganisms from Blood Culture Bottles.

Reporting of the results of routine laboratory blood culture tests to clinicians is vital to the patients' early treatment. This study aimed to perform identification and antibiotic susceptibility tests of the blood cultures showing positive signals of microbial growth in the first 12 hours of incubation by using centrifugation and Gram staining of 5 ml of liquid from the vial, thus achieving faster results. This study included 152 consecutively incubated blood culture samples showing positive microbial growth signals in the first 12 hours. The samples were centrifuged and then categorized into two groups (Gram-positive and Gram-negative) using Gram staining. Identification and antibiotic susceptibility tests were performed using an automated culture antibiogram device. For routine processing, media inoculated with positive blood culture were kept in the incubator for at least 24 hours. To compare the two methods in terms of the bacteria identification, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of the growing colony was studied. By Gram staining, the same bacterial strains were obtained for 138 (92%) of the 152 samples, similar to the results of the procedures mentioned earlier. With the samples tested with both methods, the antibiotic susceptibility profiles were compared using the antibiogram results for 1,984 samples that underwent the antibiotic testing. A 97.4% (for 1,934 antibiotic susceptibility assays) agreement was observed between the two methods. Comparing the results of the post-centrifugation Gram staining to those obtained for the specimens using routine procedures, the clinicians reported a high success rate (approximately 97%).Reporting of the results of routine laboratory blood culture tests to clinicians is vital to the patients' early treatment. This study aimed to perform identification and antibiotic susceptibility tests of the blood cultures showing positive signals of microbial growth in the first 12 hours of incubation by using centrifugation and Gram staining of 5 ml of liquid from the vial, thus achieving faster results. This study included 152 consecutively incubated blood culture samples showing positive microbial growth signals in the first 12 hours. The samples were centrifuged and then categorized into two groups (Gram-positive and Gram-negative) using Gram staining. Identification and antibiotic susceptibility tests were performed using an automated culture antibiogram device. For routine processing, media inoculated with positive blood culture were kept in the incubator for at least 24 hours. To compare the two methods in terms of the bacteria identification, matrix­assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI­TOF MS) of the growing colony was studied. By Gram staining, the same bacterial strains were obtained for 138 (92%) of the 152 samples, similar to the results of the procedures mentioned earlier. With the samples tested with both methods, the antibiotic susceptibility profiles were compared using the antibiogram results for 1,984 samples that underwent the antibiotic testing. A 97.4% (for 1,934 antibiotic susceptibility assays) agreement was observed between the two methods. Comparing the results of the post-centrifugation Gram staining to those obtained for the specimens using routine procedures, the clinicians reported a high success rate (approximately 97%).

Efforts to improve diagnosis of bacteraemia by reducing blood culture contamination in an emergency department: strategies and outcome.

OBJECTIVE: To assess the strategies and outcome for reducing blood culture contamination in order to improve the diagnosis of bacteraemia. METHODS: The interventional study was conducted at a tertiary care hospital in Karachi from January 1, 2013, to December 31, 2016. The blood culture contamination data related to the first year of the study was taken as the baseline pre-intervention data. Strategies were planned as intervention for improvement by consolidating training and education in the form of dedicated lectures, practising on mannequins and developing in-house video, replacing povidone with 2% chlorhexidine preparation spray plus 70% isopropyl alcohol swabs and inducting dedicated phlebotomy team whose only responsibility was blood sample collection and minimising the probability of error. RESULTS: In 2013, there were 8868 samples; 7402 in 2014; 6897 in 2015; and 9756 samples in 2016. The contamination rate in 2013 was 8% which went down to 7.75% in 2014, 4.25% in 2015 and 3.9% in 2016. The decline became statistically significant (p<0.001) after implementing a dedicated phlebotomy team in the emergency department. CONCLUSIONS: Apart from teaching and training, the concept of blood culture collection kit with checklist and dedicated blood collection team was found to be vital in reducing blood culture contamination.

Time to Positivity of Neonatal Blood Cultures for Early-onset Sepsis.

BACKGROUND: In newborns at risk for early-onset sepsis, empiric antibiotics are often initiated while awaiting the results of blood cultures. The duration of empiric therapy can be guided by the time to positivity (TTP) of blood cultures. The objective of the study was to determine the TTP of neonatal blood cultures for early-onset sepsis and the factors which may impact TTP. METHODS: Observational study of blood cultures growing pathogenic species obtained within 72 hours of birth from infants born at 23-42 weeks gestation, at 19 hospitals in Northern California, Boston, and Philadelphia. TTP was defined as the time from blood culture collection to the time organism growth was reported by the microbiology laboratory. RESULTS: A total of 594 blood cultures growing pathogenic bacteria were identified. Group B Streptococcus and Escherichia coli accounted for 74% of blood culture isolates. Median TTP was 21.0 hours (interquartile range, 17.1-25.3 hours). Blood cultures were identified as positive by 24 hours after they were obtained in 68% of cases; by 36 hours in 94% of cases; and by 48 hours in 97% of cases. Neither the administration of maternal intrapartum antibiotic prophylaxis, gestational age <35 weeks, nor blood culture system impacted median TTP. CONCLUSIONS: Pathogens are isolated by 36 hours after blood culture collection in 94% of neonatal early blood cultures, regardless of maternal antibiotic administration. TTP information can inform decisions regarding the duration of empiric neonatal antibiotic therapies.

Blood culture contamination in the emergency department: An integrative review of strategies to prevent blood culture contamination.

BACKGROUND: Blood culture collection remains the gold standard to diagnose bacteraemia. Current evidence suggests that the emergency department (ED) often has blood culture contamination (BCC) rates above the recommended 3%, contributing to increased hospital length of stay, unnecessary or inappropriate antimicrobial treatment, and increased economic burden. The aim of this review is to identify effective strategies to improve blood culture collection in EDs to decrease contamination rates and improve patient safety. METHODS: An integrative literature review methodology was utilised to conduct a structured search of contemporary literature using CINAHL, Embase, Medline, Pubmed and Scopus databases. All eligible literature was screened with those included in the final review collated and appraised using a quality assessment tool. RESULTS: Eleven reports were included in the final review, which identified bundled approaches, education and feedback, equipment and technique, and stakeholder engagement as strategies that improve BCC rates in the ED. CONCLUSIONS: All studies reported a reduction in BCC rates regardless of the strategies implemented. A bundled approach yielded the most significant results and was identified to be practical, inexpensive, and adaptable. Further research focusing on specific aspects of a bundled approach may be beneficial to understand which strategies are most effective.