Rapid Detection of Microorganisms by Automated Blood Culture System: Experience of 3220 cases of Blood Culture (original) (raw)
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A Comparative Study of Conventional and Automated Blood Culture System in Adult Patients
International Journal of Research and Review
Introduction: Blood culture is considered as the gold standard for the diagnosis of bloodstream infection. Conventional blood culture system is less sensitive and takes longer duration for the detection of bloodstream infections whereas automated blood culture system is more sensitive and rapid in detecting causative organisms of bloodstream infections. This prospective study was undertaken to compare the automated blood culture system with the conventional blood culture system for the identification of microbial pathogens in bloodstream infections. Method: This prospective study was done in Department of Microbiology, Silchar Medical College & Hospital, Silchar for a period of 7 months from November 2021 to May 2022. Blood samples from the patients were inoculated into BD BACTEC Plus Aerobic culture vials for automated blood culture system and Brain Heart Infusion broth for conventional blood culture system. Positive bottles flagged by the automated machine were isolated and identi...
This Prospective study analyses culture result of 134 blood culture samples received in microbiology laboratory during a five months period between October 2014 and February 2015. We have documented time required for the culture to become positive, time at which culture could be considered negative and the spectrum of isolated organismsms including their antimicrobial susceptibility patterns. The specimens were processed by using automated system BacT/Alert 3D/60. Microorganism’s identification was performed by routine conventional and automated identification system and antibiotic susceptibility testing was done by Kirby bauer disk diffusion method. The mean detection time for isolates was 14.5 +/- 5.7 hours. Among organisms isolated included were Gram positive bacteria, Gram negative bacteria and yeasts with 22 (16.4%), 14 (10.4%) and 19 (14.2%) respectively. All our cultures were positive within 34 hours.
Comparison of methods for the identification of microorganisms isolated from blood cultures
Annals of Clinical Microbiology and Antimicrobials, 2016
Background: Bloodstream infections are responsible for thousands of deaths each year. The rapid identification of the microorganisms causing these infections permits correct therapeutic management that will improve the prognosis of the patient. In an attempt to reduce the time spent on this step, microorganism identification devices have been developed, including the VITEK ® 2 system, which is currently used in routine clinical microbiology laboratories. Methods: This study evaluated the accuracy of the VITEK ® 2 system in the identification of 400 microorganisms isolated from blood cultures and compared the results to those obtained with conventional phenotypic and genotypic methods. In parallel to the phenotypic identification methods, the DNA of these microorganisms was extracted directly from the blood culture bottles for genotypic identification by the polymerase chain reaction (PCR) and DNA sequencing. Results: The automated VITEK ® 2 system correctly identified 94.7 % (379/400) of the isolates. The YST and GN cards resulted in 100 % correct identifications of yeasts (15/15) and Gram-negative bacilli (165/165), respectively. The GP card correctly identified 92.6 % (199/215) of Gram-positive cocci, while the ANC card was unable to correctly identify any Gram-positive bacilli (0/5). Conclusions: The performance of the VITEK ® 2 system was considered acceptable and statistical analysis showed that the system is a suitable option for routine clinical microbiology laboratories to identify different microorganisms.
International Journal of Medical Research and Review
Background: An important but controversial subject is the number of blood culture sets required for the diagnosis of blood stream infection (BSI) and also the use of appropriate antibiotics to treat bacteremia. This paper focuses on the need of two blood culture set in comparison to one blood culture in the diagnosis of bacteraemia. Methods: First and second sets were collected aseptically from two different sites at an interval of about one hour from all clinically suspect patients of bacteremia. The samples were processed in Bact/ALERT3D system and further identified in VITEK 2 compact. Results: Second blood culture set yielded higher rates of positive cultures (63%) than first set (37%). The common bacterial isolates were Coagulase negative Staphylococcus (CoNS) 29 (28%), followed by Staphylococcus aureus 20 (20%), Escherichia coli 13 (13%) and Klebsiella pneumonia 11(11%). Methicillin resistance was observed in 90% of S. aureus isolates. All Gram positive bacteria were found sensitive to vancomycin. In Gram-negative organisms, extended spectrum β-lactamases (ESBL) was observed in 40.5% isolates and resistance to carbapenems was found to be 37.8%. Discussion/Conclusion: In India, most hospitals routinely use single aerobic blood culture. The isolation of CoNS in blood is difficult to interpret hence, proper collection, processing, and relevant clinical information can significantly reduced the chances of contamination. Automated blood culture system can significantly shorten the length of time for isolation and identification compared to the manual techniques which takes about seven days. Resistance to antibiotics is a matter of concern that can result in ineffective treatment.
IP innovative publication pvt. ltd, 2019
Aim: To determine the appropriateness of blood volume in automated blood culture bottles of the BACT/ALERT 3D system, its effect on isolation rate and time to positivity of pathogens. Materials and Methods: The study was carried out in a tertiary care hospital in South India from 1st March 2018 to 31st August 2018. Automated blood culture bottles sent to Microbiology laboratory for blood culture were included in the study. The bottles were weighted by electronic weighing balance. The filled blood culture bottles received at microbiology laboratory were re-weighed and was categorized into appropriately filled and inappropriately filled bottles. Frequency of appropriately filled bottles and inappropriately filled bottles was expressed in percentage. Result: A total of 8740 blood culture bottles were included in the study, out of which the blood volume was found to be suboptimum in 3978 bottles (45.5%), optimum in 3498 bottles (40%) and overfilled in 1264 bottles (14.5%). There was an increase in the number of blood culture bottles with optimum blood volume from 35.1% in March to 58.12% in August. The average TTP for true pathogens was found to be 16.72 hrs. with optimum blood volume, 17 hrs. with overfilled blood volume and 21.5 hrs. with sub-optimum blood volume. The isolation rate for true pathogens was found to be 88.62% with optimum blood volume, 86.43% with overfilled blood volume and 70.01% with sub-optimum. The false positive rate was found to be 4.1% with overfilled blood volume, 1.6%with sub-optimum and 1.4%with optimum blood volume. Conclusion: Through this study, the correlation between the blood volume with the isolation rate, time to positivity and false positivity of blood culture isolates was established.
Blood Culture Techniques: Increasing Yields and Reducing Contamination
Sri Lanka Journal of Critical Care, 2009
Bloodstream infections are associated with significant patient mortality and health care costs. Isolation of the causative organism will direct the clinician to institute specific treatment. But isolation of the implicating organism is hampered by lack of yield and increased level of contamination. The rates of contamination and reduced yield are more relevant in Sri Lanka as most of our public sector laboratories use manual blood culture system and do not adhere to correct aseptic techniques of blood collection. This has led to delay in identifying the causative organism. Increase rates of contamination not only have hindered specific treatment but also have prompted clinicians to use antibiotics of increased cost and toxicity. Though differentiation between true pathogen and contamination is not clearly set, certain parameters, namely identification of the organism, proportion of the positive blood culture sets, Number of positive blood culture bottles within a blood culture set, ...
Clinical Microbiology and Infection, 2014
Detection of microorganisms by blood cultures (BCs) is essential in managing patients with bacteraemia. Rather than the number of punctures, the volume of blood drawn is considered paramount in efficient and reliable detection of microorganisms. We performed a 1-year prospective multicentre study in adult emergency departments of three French university hospitals comparing two methods for BCs: a unique blood culture (UBC) collecting a large volume of blood (40 mL) and the standard method of multiple blood cultures (MBC). The performances of both methods for bacterial contamination and efficient microbial detection were compared, each patient serving as his own control. Amongst the 2314 patients included, three hundred were positive for pathogens (n = 245) or contaminants (n = 55). Out of the 245 patients, 11 were positive for pathogens by UBC but negative by MBC and seven negative by UBC but positive by MBC (p 0.480). In the subgroup of 137 patients with only two BCs, UBC was superior to MBC (p 0.044). Seven and 17 patients had contaminated BCs by UBC and MBC only, respectively (p 0.062). Considering the sums of pathogens missed and contaminants, UBC significantly outperformed MBC (p 0.045). Considering the complete picture of cost savings, efficient detection of microorganisms and decrease in contaminations, UBC offers an interesting alternative to MBC.
Early Detection of Blood Borne Pathogens and its Antibiotic Susceptibility
https://www.ijhsr.org/IJHSR\_Vol.12\_Issue.4\_April2022/IJHSR-Abstract.028.html, 2022
In this study the evaluation of the new blood culture technique to improve rapid detection for the presence of bacteria in blood by using Tetrazolium dye (TTC) was done. The Blood samples were collected and processed by two different methods i.e. conventional blood culturing method and improved method by using TTC dye. In conventional method the sample was inoculated in blood culture bottle and then plated on blood agar, MacConkey, and chocolate agar and was incubated for 24hrs. After incubation the growth observed was identified and reported. Along with this in Improved TTC dye method the blood was inoculated in tryptone soya broth incubated and then TTC dye was added in it and cherry red color development was considered as positive. In the present study, total 50 blood samples were processed of which 32 samples exhibited growth on media and 18 samples show no growth. From total positive growth samples, 9 were gram positive including Staphylococcus aureus, Staphylococcus haemolyticus and Staphylococcus epidermidis and remaining 23 were gram negative rods including E. coli, Pseudomonas aeruginosa and Klebsiella pneumonia. Overall, the average time required for growth by conventional method is 51 hours while that of TTC dye method is of 30 hours. In contrast to antibiotic susceptibility test, Microbroth dilution method was easy, reliable, affordable and quick result giving method as compare to standard antibiotic susceptibility test method.
Indian Journal of Critical Care Medicine, 2016
Introduction: Bloodstream infection (BSI) is a leading cause of mortality in critically ill patients. The mortality directly attributable to BSI has been estimated to be around 16% and 40% in general hospital population and Intensive Care Unit (ICU) population, respectively. The detection rate of these infections increases with the number of blood samples obtained for culture. The newer continuous monitoring automated blood culture systems with enhanced culture media show increased yield and sensitivity. Hence, we aimed at studying the role of single and multiple blood specimens from different sites at the same time in the outcome of automated blood culture system. Materials and Methods and Results: A total of 1054 blood culture sets were analyzed over 1 year, the sensitivity of one, two, and three samples in a set was found to be 85.67%, 96.59%, and 100%, respectively, which showed a statistically significant difference (P < 0.0001). Similar findings were seen in few more studies, however, among individual organisms in contrast to other studies, the isolation rates of Gram-positive bacteria were less than that of Gram-negative Bacilli with one (or first) sample in a blood culture set. In our study, despite using BacT/ALERT three-dimensional continuous culture monitoring system with FAN plus culture bottles, 15% of positive cultures would have been missed if only a single sample was collected in a blood culture set. Conclusion: The variables like the volume of blood and number of samples collected from different sites still play a major role in the outcome of these automated blood culture systems.
PCR evaluation of false-positive signals from two automated blood-culture systems
Journal of Medical Microbiology, 2006
Rapid detection of micro-organisms from blood is one of the most critical functions of a diagnostic microbiology laboratory. Automated blood-culture systems reduce the time needed to detect positive cultures, and reduce specimen handling. The false-positive rate of such systems is 1–10 %. In this study, the presence of pathogens in ‘false-positive’ bottles obtained from BACTEC 9050 (Becton Dickinson) and BacT/Alert (Biomérieux) systems was investigated by eubacterial and fungal PCR. A total of 169 subculture-negative aerobic blood-culture bottles (104 BacT/Alert and 65 BACTEC) were evaluated. Both fungal and eubacterial PCRs were negative for all BACTEC bottles. Fungal PCR was also negative for the BacT/Alert system, but 10 bottles (9·6 %) gave positive results by eubacterial PCR. Sequence analysis of the positive PCR amplicons indicated the presence of the following bacteria (number of isolates in parentheses): Pasteurella multocida (1), Staphylococcus epidermidis (2), Staphylococc...