Comparison of BacT/Alert FAN and FAN Plus Bottles with Conventional Medium for Culturing Cerebrospinal Fluid

Blood culture bottles for culturing cerebrospinal fluid in cases of bacterial meningitis caused by Enterococcus faecalis: A case report

Pathogen identification is essential for the treatment of bacterial meningitis. However, cerebrospinal fluid (CSF) culture tests are often negative when antimicrobial agents are administered before CSF is collected. Therefore, it is necessary to improve the culturing process for such samples. Here, we report a case of bacterial meningitis where the causative bacteria were detected by inoculating that patient's CSF samples into blood culture bottles. A 52-year-old man developed a fever and headache after undergoing transnasal transsphenoidal surgery for a nonfunctioning pituitary neuroendocrine tumor. He was suspected of having a wound infection, for which he was treated with cefozopran and vancomycin. A CSF test was also performed, owing to persistent fever, and bacterial meningitis was suspected. Although conventional CSF culture tests were negative, CSF cultures using blood culture bottles detected Enterococcus faecalis. The antimicrobial agents were therefore changed to ampicillin and gentamicin, after which the patient's meningitis improved. The blood culture bottles used contained adsorbed polymer beads with antimicrobial neutralizing properties, which likely contributed to the isolation of the bacteria. In addition to conventional cultures, ones done in blood culture bottles may be useful for diagnosing bacterial meningitis via CSF samples-particularly in cases where antimicrobial agents have already been administered.

Evaluation of the Accelerate Pheno System for Rapid Identification and Antimicrobial Susceptibility Testing of Positive Blood Culture Bottles Inoculated with Primary Sterile Specimens from Patients with Suspected Severe Infections

The Accelerate Pheno system is approved for rapid identification and phenotypic antimicrobial susceptibility testing (AST) of microorganisms grown from positive blood cultures inoculated with blood from septic patients. We evaluated the performance of the system for identification and AST from positive blood culture bottles inoculated with primary sterile nonblood specimens from patients with suspected severe infections. One hundred positive blood culture bottles with primary sterile specimens (63 cerebrospinal fluids, 16 ascites, 7 pleural fluids, 4 vitreous fluids, 5 joint aspirates, and 5 other aspirates) from 100 patients were included. Pathogen identification was in agreement with conventional methods for 72 of 100 cultures (72%) and for 81 of 112 (72%) pathogens when considering all pathogens and for 72 of 92 (78%) cultures and 81 of 104 (78%) pathogens when considering on-panel pathogens only. Eight of 31 isolates (26%) not identified by APS were pathogens not included in the APS panel. APS and conventional methods accordingly identified all pathogens from two of nine polymicrobial cultures (22%). APS generated antimicrobial resistance results for 57 pathogens of 57 cultures. The overall category agreement between APS and culture-based AST was 91.2%; and the rate for minor errors was 6.9%, for major was 1.7%, and for very major errors was 0.2%. APS may accelerate pathogen identification and phenotypic AST from positive blood culture bottles inoculated with primary sterile specimens from patients with serious infections, especially for hospitals without an on-site microbiology laboratory. However, the inclusion of nonblood specimens with a high likelihood of polymicrobial infections may result in an inferior performance.

A case of gonococcal meningitis caused by Neisseria gonorrhoeae MLST ST7363 in a healthy young adult

A 37-year-old healthy man was admitted with fever, skin rash, migratory arthralgia, and headache without preceding urogenital symptoms. Sexual contact history and positive CSF culture for Neisseria gonorrhoeae using BacT/Alert blood culture bottles were diagnostic for gonococcal meningitis. Multilocus sequence typing of this isolate showed sequence type (ST) 7363, the most predominant ST among ceftriaxone-resistant strains. The isolate from this case remained susceptible to ceftriaxone although it was resistant to penicillin, tetracycline, and ciprofloxacin. With the high selective pressure of ceftriaxone for treatment of plasmid-mediated β-lactamase producing N. gonorrhoeae, resistance to ceftriaxone and molecular characteristics should be monitored.

Performance of the BacT/Alert Virtuo Microbial Detection System for the culture of sterile body fluids: prospective multicentre study

OBJECTIVES

Continuous monitoring blood culture systems are commonly used for sterile body fluid cultures. In this multicentre study, we evaluated the performance of the new-generation BacT/Alert Virtuo system compared to the BacT/Alert 3D and conventional culture for the recovery of microorganisms from sterile body fluids.

METHODS

Peritoneal, cerebrospinal, pericardial, pleural and synovial fluids from adult patients submitted for culture were collected from three different centres. Specimens were inoculated into two bottles of the same bottle type (SA, SN, FA Plus or FN Plus) in equal volumes for simultaneous incubation in the Virtuo and 3D instruments. Each specimen was also Gram stained and seeded to solid media.

RESULTS

A total of 811 specimens were inoculated to 1257 bottle pairs. The Virtuo and 3D showed equivalent recovery of clinically significant microorganisms (127/155, 81.9%, vs. 126/155, 81.3%, respectively). Solid media cultures recovered fewer pathogens than either continuous monitoring system (95/155, 61.3%, p <0.001), including significantly fewer Enterobacteriaceae and enterococci. The Virtuo was significantly faster than the 3D in median time to detection of isolates from the same specimen (12.5 (range, 2.8-101.5) hours vs. 15.5 (range, 4.3-78.5) hours, p <0.001). Direct specimen Gram stain detected the eventual pathogen in 30 (26.1%) of 115 significant positive specimens.

CONCLUSIONS

The BacT/Alert Virtuo system was equivalent to the 3D system in organism recovery from sterile body fluid culture but showed faster detection of growth as a result of design enhancements.