Bact alert fa

In the first stage, 200 archived Gram-negative isolates of different species and various drug susceptibility patterns were collected and used to evaluate the ability of the MBT STAR-BL to detect β-lactamase-mediated resistance to all claimed antibiotics except ertapenem, which was not available locally. All strains were isolated from BCs previously collected at four different public hospitals throughout the territory. Escherichia coli strain DH5a was used as a β-lactamase-negative control strain, whereas ATCC E. coli strain BAA-2452, a NDM-1 carbapenemase producer, was used as a positive control in all drug hydrolysis tests.
In the second stage, 153 positive BC broths derived from patients with Gram-negative bacterial bloodstream infections were collected prospectively from January to December 2016. BACTEC™ FX (Becton Dickson, US) and BacT/Alert FA (bioMerieux, France) blood culture system are housed in hospitals. All positive BCs were subjected to direct Gram staining. If Gram-negative rods were found, a 5-mL aliquot of culture broth was transported to our laboratory for direct bacterial identification, followed by the detection of β-lactamase-mediated resistance using MBT STAR-BL within the same day.
On the following day, MALDI-TOF MS analyses were repeated using isolated colonies grown on subculture plates.

Standard CLSI media and Mueller–Hinton agar (MHA) were used. AST was performed on 90-mm circular plates produced in-house using agar from Oxoid (Thermo Fisher Scientific, Basingstoke, United Kingdom). Aerobic (BACT/ALERT^® FA, LOT 0001056014) and anaerobic (BACT/ALERT^® SN, LOT 0001055094) BC bottles (bioMerieux, Marcy, France). Antibiotic disks (Oxoid, Thermo Fisher Scientific, Basingstoke, United Kingdom) were chosen to represent relevant agents or agent groups used in the treatment of BSI (Table 1).

A total of 364 positive blood culture broths from non-duplicated patients with suspected sepsis were collected from January 2014 to May 2014 at four public acute hospitals located at different district areas across Hong Kong, namely 1,633 bed Pamela Youde Nethersole Eastern Hospital (PYNEH), 1,753 bed Princess Margaret Hospital (PMH), 1,403 bed United Christian Hospital (UCH) and 1,702 bed Queen Mary Hospital (QMH). Bactec plus/F (Becton Dickson, US) aerobic culture bottles were used in all the study sites except for PMH where the BacT/Alert FA (bioMerieux, France) system was used. The bottles were incubated in the corresponding automated blood culture system until positive within five days. Upon broth positivity, samples from PYNEH, PMH and UCH were sent to The Hong Kong Polytechnic University for the Verigene Blood Culture Test within 24 hours. If the samples could not be run within 24 hours, they were stored at 4°C for up to 48 hours. For QMH, after flagging positive by the blood culture system, the samples were almost processed immediately with BC-GP or BC-GN tests using another Verigene system established in their laboratory.

Spiked blood samples were cultured in BacT/Alert^® FA plastic blood culture bottles (bioMérieux Inc., Durham, NC, USA). This was done by inoculating 10 mL of a spiked blood sample into a blood culture bottle containing 40 mL of growth medium.

Blood culture bottles from suspected sepsis patients were collected from December 2012 to June 2013 at the 801 bed National Center for Global Health and Medicine (NCGM), from February to June 2013 at 572 bed NCGM Kohnodai Hospital, and from March to June 2013 at 1423 bed Tokyo Women's Medical University (TWMU) hospital. Bactec plus/F (Becton Dickinson) and BacT/Alert FA (bioMérieux, Tokyo, Japan) blood culture bottles were used at NCGM and TWMU, respectively. Of 102 clinical samples, 79 and 23 were collected at NCGM and TWMU, respectively. Hospital departments and wards were not specified in the study. The bottles were incubated in the automated blood culture system until positive. Positive blood cultures showing Gram-negative bacteria were tested with the BC-GN assay. To select samples containing organisms listed in the BC-GN panel, positive blood cultures were stored at room temperature and tested within 5 days of positivity. The average of storage periods was 3.1±1.4. Only one positive blood culture per patient was included in the study.