Comparative study of manual conventional blood cultures versus automated blood culture system in cases of septicemia

: Blood cultures are a proven gold standard method for the identification of causative agents of bloodstream infections. Identification of causative organism along with antibiotic susceptibility plays a pivotal role in proposing suitable antibiotic therapy. Automated blood culture systems show improved monitoring of blood cultures by reducing the time and by ensuring more accurate results when compared to the conventional blood culture system. To isolate the organism from given blood samples of a suspected case of septicemia and to compare the results of conventional and automated blood culture systems and to study the antimicrobial susceptibility pattern of the pathogens isolated. A prospective study of 6 months period was conducted among 100 subjects attending the Department of Microbiology in a tertiary care hospital. Subjects with symptoms and signs of septicemia were included. 25ml of venous blood was drawn aseptically from the venipuncture site, of which 5ml of blood was inoculated into 50ml of Brain Heart Infusion bottle in conventional blood culture system and 10ml each into aerobic and anaerobic BACTEC PLUS bottle in Automated blood culture system BACTEC FX40. Overall, 48% and 60% of the samples revealed positive growth by the conventional and automated blood culture system BACTEC FX40, respectively. Gram Positive Cocci were 52.08% and Gram Negative Bacilli were 47.91% isolated by conventional blood culture system, whereas automated blood culture system BACTEC FX40 isolated 45% and 55%, respectively. Isolates were detected within 24-48hrs and 12-24 hrs by conventional and automated blood culture systems, respectively. The anti-microbial susceptibility pattern of the pathogens isolated was also recorded by Kirby Bauer disc diffusion method of antimicrobial susceptiblity testing. Automated blood culture systems are a trustworthy substitute to conventional blood culture systems. The automated blood culture systems being more sensitive and rapid in detecting septicemia in subjects acts as an appropriate means for the initial identification and detection of blood pathogens and improved provision of antimicrobial therapeutic options for septic Patients especially in Critical Care and Intensive Care Units where positive culture reporting is crucial.

Real World Evaluation of the Impact of Implementation of the VIRTUO Blood Culture System in a Tertiary Care Hospital

The bioMerieux BACT/ALERT VIRTUO (VIRTUO) blood culture system used in combination with resin-containing media may enhance the growth of microorganisms. Our objective was to assess the impact of transitioning to the VIRTUO system in comparison to the VersaTREK blood culture system at a tertiary care medical center. We retrospectively reviewed all blood cultures performed at a 1250-bed academic medical center between January-December 2018 (VersaTREK) and January-December 2019 (VIRTUO). Blood culture positivity rates and contamination rates were compared pre- versus post-VIRTUO implementation. Of 101,438 blood cultures performed during the study period, 48,839 (48.1%) were processed pre-implementation and 52,599 (51.9%) post-implementation. The blood culture positivity rate increased from 8.1% pre-implementation to 11.7% post-implementation (p<0.001). Staphylococcus aureus was the most frequently isolated species in both time periods and had higher recovery rate post-implementation (1.5% of all blood cultures obtained pre- vs. 3.4% post-implementation, p<0.001). A higher recovery rate in the post-implementation period was also noted for coagulase-negative staphylococci (1.9% pre- vs. 2.7% post-implementation, p<0.001), as well as modest but statistically significant changes for E. coli (0.8% vs. 1.0%, p<0.001), K. pneumoniae (0.4% vs. 0.5%, p=0.005) and Candida albicans . (0.1% vs. 0.2%, p=0.038). The inpatient blood culture contamination rate was higher post-implementation (1.5% pre- vs. 1.9% post-implementation, p<0.001). The VIRTUO blood culture system was associated with a higher observed proportion of positive blood cultures compared to the previous VersaTREK system. Future studies are needed to assess whether an increased rate of positive blood cultures is associated with changes in clinical outcomes.

Prevalence and Antibiotic Resistance Pattern of Salmonella typhi and Salmonella paratyphi A isolated by Automated Blood Culture System

Background: Salmonella thyphi and Salmonella paratyphi A are the members of Enterobactoriaceae and gram negative rods causing typhoid fever & partyphoid fever respectively. Automated blood culture system is the standard diagnostic method. Objective: The purpose of the present study was to see the prevalence and antibiotic resistance pattern of Salmonella typhi and Salmonella paratyphi A isolated by automated blood culture system. Methodology: This cross-sectional study was done in the Microbiology Lab at IBN Sina D. Lab and consultation center, Doyagonj, Dhaka, Bangladesh from January 2019 to June 2019. Blood culture was performed by automated blood culture method. Sensitivity pattern of antibiotic was measured by Disk diffusion method. Result: A total of 3240 blood samples were collected from suspected patients. Among them, bacteria were isolated 336 (10.37%). The most common isolated bacteria were Salmonella typhi which was 261(77.68%) cases and Salmonella paratyphi A which was in 60 (17.86%) cases. Salmonella typhi is the most common organism and showed sensitivity pattern to imipenem 97.3%, colistin 80.46% and amikain 77.4% and Salmonella paratyphi A showed. Sensitivity pattern to imipenem 93.3% and amikacin 83.3%. Conclusion: In conclusion high rate of Salmonella typhi and Salmonella paratyphi A are isolated during blood culture showing less sensitive to imipenem and amikacin. Bangladesh Journal of Infectious Diseases 2020;7(2):57-60

Comparative study between automated blood culture and conventional blood culture in neonatal septicaemia cases isolated in a tertiary care hospital in Odisha

Background: Neonatal sepsis is the third leading cause of neonatal mortality and a major public health problem, especially in developing countries. In developing countries sepsis being cause of neonatal mortality is responsible for 30-50% of the 5 million of total neonatal deaths each year. The detection of microorganisms in a patient's blood has a great diagnostic and prognostic significance. Blood cultures provide essential information for the evaluation of a variety of diseases like endocarditis, pneumonia, and pyrexia of unknown origin particularly in patients with suspected sepsis. In our study we have done blood cultures from patients on a neonatal intensive care unit by both automated and conventional system simultaneously and have done comparative analysis between the two systems.Methods: The aim of this study was to compare the results of blood culture employing the conventional and BacT/Alert and VITEK-2 methods for detection of neonatal septicaemia cases. A prospective study was carried out in the Department of Microbiology in association with Department of Paediatrics and NICU, of Kalinga Institute of Medical Sciences, Bhubaneswar. 250 neonates with clinically suspected septicaemia were included in the study group. Three (3) ml of venous blood was collected aseptically of which 2ml was cultured by automated BacT/Alert and VITEK-2 method for rapid isolation and sensitivity test and rest 1 ml of blood for conventional culture.Results: Isolation of bacterial pathogens by culture using the automated system showed greater positivity (32.8%) as compared to 18% by conventional blood culture system.Conclusions: This study shows that automated blood culture system is superior to conventional blood culture system in terms of rapid and specific isolation of organism.