Causes and Countermeasures for False-Positive Blood Cultures

The colorimetric blood culture system employs a colorimeter sensor and the principle of reflected light to monitor the production and presence of carbon dioxide (CO2) dissolved in the culture medium. Microorganisms present in the sample generate CO2 during their metabolic processes or as they break down sugars, causing changes in the pH of the culture medium. These pH shifts lead to a lightening of the color of the semi-permeable silicone material (Liquid Emulsion Sensor, LES) at the bottom of the culture bottle. By continuously acquiring signals via an illumination sensor, a response curve is generated for analysis, and positive results are promptly detected using three computational algorithms: the initial threshold method, the slope method, and the acceleration method. Clinical work…

Expert Consensus on Strategies for Managing Infections Caused by Enterobacteriaceae Producing Extended-Spectrum β-Lactamases in China

Enterobacteriaceae are the most important pathogens in clinical bacterial infectious diseases, and the primary mechanism of resistance among these bacteria is the production of extended-spectrum β-lactamases (ESBLs). ESBLs are plasmid‑mediated β‑lactamases that can hydrolyze penicillins, oximinocephalosporins—including third- and fourth‑generation cephalosporins—and the monobactam antibiotic aztreonam; they are also inhibited by β‑lactamase inhibitors. The diagnosis of infections caused by ESBL‑producing Enterobacteriaceae and their prompt, appropriate treatment have become critical clinical priorities.

Clinical adherence to prophylactic antibiotic use in cesarean deliveries as recommended by guidelines is poor.

Research indicates that, today, clinicians often do not administer prophylactic antibiotics to many women undergoing cesarean delivery, despite evidence‑based guidelines recommending such practice. Dr. Sara G. Brubaker of Columbia University’s Mailman School of Public Health in New York City and her colleagues investigated this issue and found that, between 2003 and 2010, nearly 40% of women in the United States who underwent cesarean delivery did not receive perioperative antibiotic prophylaxis on the day of surgery—despite the American College of Obstetricians and Gynecologists’ recommendation for prophylactic antibiotic use in this population. Dr. Brubaker and her team noted that this discrepancy…

Quality Control of the Fungal G Test

Fungi are eukaryotic microorganisms whose cell walls contain chitin and β‑glucans. The 1,3‑β‑D‑glucan component of the fungal cell wall can specifically activate Factor G in limulus amebocyte lysate, triggering a cascade of enzymatic reactions that ultimately react with a chromogenic substrate—limulus tripeptide‑PNA conjugate—yielding a measurable optical signal at a specific wavelength. This enables the quantitative detection of 1,3‑β‑D‑glucan, a method also known as the G test (colorimetric assay). The G test is capable of detecting a variety of fungal infections, including those caused by Candida and Aspergillus.

Gold Standard for Sepsis—Blood Culture Procedure Guidelines

I. Collection and Culture of Blood Specimens (1) Timing of Blood Culture Collection Requirements: For patients suspected of bacteremia or fungemia, blood culture specimens should be collected immediately before initiating antimicrobial therapy. At least two sets of blood cultures—each set comprising one aerobic bottle and one anaerobic bottle—should be obtained simultaneously or at closely spaced intervals. Note: Experimental data indicate that approximately one hour after bacteria enter the bloodstream, chills and fever typically begin to develop within two hours. This time frame represents the optimal window for collecting blood cultures to isolate the causative pathogen. Collecting blood samples at other time points is warranted only under the following circumstances: suspicion of infective endocarditis or other…

[International Medical Updates] Prevention of Early-Onset Group B Streptococcus Infection in Newborns

Prevention of Early-Onset Group B Streptococcus Infection in Newborns In October 2013, the Society of Obstetricians and Gynaecologists of Canada (SOGC) published a revised guideline for the prevention of early-onset Group B Streptococcus (GBS) infection in newborns. Drawing on a retrospective review of relevant evidence from the literature, the guideline outlines intrapartum management strategies to prevent early-onset GBS infection. The key updates in this revision include: