Evaluation of the performance of GeneSoC®, a novel rapid real-time PCR system, to detect Staphylococcus aureus and methicillin resistance in blood cultures.

Staphylococcus aureus bacteremia results in substantial mortality. Rapid identification and the determination of methicillin susceptibility are crucial for immediate treatment with appropriate antibiotics. In the present study, we aimed to evaluate the basic assay performance of GeneSoC®, a novel rapid quantitative polymerase chain reaction (qPCR) method, for the detection of methicillin-susceptible (MS) or -resistant (MR) S. aureus in blood culture (BC) bottles. qPCR pimers and probes were desinged for femA and mecA genes to diagnose S. aureus and its methicilline-resistance status. GeneSoC® system can detect target genes within 12 min per sample using microfludic thermal cycling. A total of 100 BC-positive samples, showing clusters of gram-positive cocci using microscopy, were tested. The analytical sensitivity was demonstrated for the target sequence of femA and mecA genes at 10 copies/µL, respectively. The detection limit of the MRSA bacterial burden using this system was 104 and 103 CFU/mL for femA and mecA, respectively. Compared with culture-based identification and susceptibility testing, the sensitivity and specificity for the detection of femA (+)/mecA (+) MRSA using GeneSoC® were 90.9 and 98.9%, respectively, whereas the sensitivity and specificity for detection of femA (+)/mecA (-) MSSA were 96.2% and 97.3%, respectively. In conclusion, although this was a small sample and pilot study, the GeneSoC® system is beneficial for rapid, reliable, and highly sensitive real-time testing of MRSA and MSSA in BC bottles.

Education of medical personnel optimizes filling volume of blood culture bottles without negatively affecting microbiology testing.

BACKGROUND: Anemia is a risk factor for adverse outcomes, which can be aggravated by unnecessary phlebotomies. In blood culture testing, up to 30 ml of blood can be withdrawn per sample, even though most manufacturers recommend blood volumes of 10 ml or less. After assessing the filling volume of blood culture bottles at our institution, we investigated whether an educational intervention could optimize filling volume of blood culture bottles without negatively affecting microbiology testing. METHODS: We weighed 10,147 blood cultures before and 11,806 blood cultures after a six-month educational intervention, during which employees were trained regarding correct filling volume via lectures, handouts, emails, and posters placed at strategic places. RESULTS: Before the educational intervention, only 31% of aerobic and 34% of anaerobic blood cultures were filled correctly with 5-10 ml of blood. The educational intervention increased the percentage of correctly filled bottles to 43% (P < 0.001) for both aerobic and anaerobic samples without negatively affecting results of microbiologic testing. In addition, sample volume was reduced from 11.0 ± 6.5 to 9.4 ± 5.1 ml (P < 0.001) in aerobic bottles and from 10.1 ± 5.6 to 8.8 ± 4.8 ml (P < 0.001) in anaerobic bottles. CONCLUSION: Education of medical personnel is a simple and effective way to reduce iatrogenic blood loss and possibly moderate the extent of phlebotomy-induced anemia.

Significance of blood culture testing after pancreatoduodenectomy.

Aim: The aim of this study was to clarify the significance of blood culture testing in the postoperative period of pancreatoduodectomy (PD), a highly invasive surgery. Methods: Rates of blood culture sampling and positivity were investigated for febrile episodes (FEs) in patients who underwent PD (2016-2021). FEs were defined as body temperature of 38.0°C or higher occurring on or after the 4th postoperative day. Fever origin was diagnosed retrospectively, and FEs were classified as pancreatic fistula (PF)-related or PF-unrelated FEs. Factors correlated with blood culture positivity were explored. Results: Among 339 patients who underwent PD, 99 experienced 202 FEs. Blood culture testing was performed on 160 FEs occurring in 89 patients. The sampling and positivity rates were 79.2% and 17.5%, respectively, per episode and 89.9% and 28.1%, respectively, per patient. Thirty-six FEs were classified as PF-related and 124 were classified as PF-unrelated FEs. The blood culture positivity rate was significantly lower in PF-related vs. PF-unrelated FEs (1/36 vs. 27/124, respectively, p = 0.006). The blood culture positivity rate was significantly higher in patients with cholangitis, catheter-related blood stream infection, and urinary tract infection than PF-related FEs. Multivariate analysis showed that blood culture positivity was negatively associated with PF-related FEs and positively associated with accompanying symptoms of shivering, Pitt Bacteremia Score, and preoperative biliary drainage. Conclusions: Patients who underwent PD showed relatively high blood culture positivity rates. Based on these results, it may be possible to distinguish PF-related and -unrelated FEs.