Sterility control (bact/alert)

Technical information

Utility

• Bacterial or fungal contamination of human-origin products (SoHo) can lead to morbidity and mortality in recipients. Possible sources of contamination include asymptomatic bacteremia in the donor at the time of donation and incorrect aseptic techniques during production.

• The European Pharmacopoeia allows for the use of automated sterility control methods in chapter 2.6.27. The BACT/ALERT® system uses a detection principle based on the carbon dioxide generated by microbial growth associated with the metabolism of the culture medium substrates, which results in a pH change, leading to an irreversible colour change of the bottle bottom indicator. This system is advantageous in terms of the speed it provides in microbial detection and recovery, as results are obtained within a maximum of 14 days through continuous reading, and furthermore, the notification of positive samples is immediate. The samples to be analysed undergo minimal manipulation since only the bottles need to be inoculated and placed in the BACT/ALERT cabinet for incubation. The colour reading is automatic, there is no interference from turbidity, and it is a non-destructive method that allows for subsequent microbial identification and antibiogram, if necessary.

• The utility of this technique is to perform sterility control of products that need to be sterile, such as blood components (platelets, red blood cell concentrates), umbilical cord blood, apheresis, cell therapies, advanced therapies, tissues, starting materials, media, reagents, etc.

In bottles with an aerobic atmosphere, the growth of aerobic microorganisms (bacteria and fungi) is favoured. In bottles with an anaerobic atmosphere, the growth of anaerobic and facultative anaerobic microorganisms is favoured. Between 1 and 10 mL of sample can be inoculated into each bottle, always inoculating the maximum amount whenever possible.

Method

BACT/ALERT (Figure 1) is an automated microbial detection system that provides a suitable environment for the growth of a wide range of microorganisms, including bacteria and fungi. BACT/ALERT can be programmed to incubate at different temperatures for different periods of time. Generally, the bottles are incubated in the incubator module at 37°C or 32°C for 7 or 14 days, depending on the type of bottle, to detect the potential growth of contaminating microorganisms: aerobic bacteria, anaerobic bacteria, filamentous fungi, or yeasts.

The equipment controls the pre-programmed incubation time according to the type of bottle recognised by barcode reading. The instrument reads the bottles every ten minutes and detects growth by the pH change generated by microbial growth, which results in a colour change of the bottle bottom indicator. When the system detects a positive sample, it provides a visual and audible alert.

Various types of bottles are used for culturing microorganisms depending on the product being studied. Their characteristics are summarised in Table 1.

Bottles labelled with an "i" have passed an extensive batch quality control test that makes them suitable for use according to good manufacturing practices (GMP).

Table 1: Summary table of bottle types

Prior to using a batch of BACT/ALERT bottles, their fertility must be demonstrated through a growth promotion test, as indicated in the Pharmacopoeia.

The inoculation of BACT/ALERT bottles is done, whenever possible, in the white rooms under the responsibility of the teams producing blood components, tissues, cell therapies, or advanced therapies. In cases

Specimen information

Sample: Product to be used for sterility verification

Tubes: BACT/ALERT vial (see details in Table 1 and Table 2)

Stability: Transport to the laboratory as soon as possible.

Transport instructions: Room temperature.

Reason for rejection: Unidentified vial, illegible label, etc.

Administrative information

BST Code: See Table 2

Old BST Code: See Table 2

Test Description: See Table 2

Synonyms: Blood culture, Sterility control, BACT/ALERT

Section: Microbiology

BST Rates: Check the updated rates here.

Table 2: Summary table of tests

Profiles:
No applicable

References

• Guide to the quality and safety of tissues and cells for human application. 5th edition EDQM, 2022

• Farmacopea Europea 11ena edició, 2023

• Estándares en hemoteràpia CAT

• FACT-JACIE International Standards for Cellular Therapy Product Collection, Processing, and Administration.

• NETCORD-FACT International Standards for Cord Blood Collection, Banking, and Release for Administration.

• NCF: Guía de Normas de Correcta Fabricación de Medicamentos de Uso Humano y Veterinario. Anexo 1

• NCF Parte IV: Directrices sobre normas de correcta fabricación específicas para Medicamentos de Terapia Avanzada.

• GpG. Directrices de Buenas Prácticas - Guía para la preparación, uso y control de calidad de los componentes sanguíneos.

• Guia de l'usuari del BACT/ALERT 3D (Biomérieux)

• Instruccions dels flascons iFA Plus, iFN Plus, FA Plus, FN Plus, BPA, BPN, iAST, iASN