Table 1.
Author | Year | Reference | Blood culture system | Gram neg. bacteria n (% pos. ID) |
Gram pos. bacteria n (% pos. ID) |
Fungi n (% pos. ID) |
Total monomicrobial samples n (% pos. ID) | Log(score) cut-off used |
Comments |
---|---|---|---|---|---|---|---|---|---|
Schubert et al. | 2011 | [25] | Bactec 9240 | 98 89.8% species |
358 86.3% species |
17 70.6% species |
473 86.5% species |
>1.5 species | ID up to 48 hours earlier compared to conventional methods In 18 of 27 mixed cultures at least one isolate was identified correctly Misidentified were 5 Streptococcus mitis as Streptococcus pneumonia |
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Kok et al. | 2011 | [56] | Bactec FX Plus Aerobic/F Anaerobic/F Lytic/10 |
187 87.2% genus 79.7% species |
285 68.4% genus 46.3% species |
— | 472 75.8% genus 59.5% species |
>1.7 genus >2.0 species | All genus results would be reported as species results by present day software Misidentified were 4 Streptococcus mitis as Streptococcus pneumonia, corrected in later databank updates |
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Yan et al. | 2011 | [41] | Bactec FX | — | — | 42 100% species |
42 100% species |
>1.9 species | LOD of yeast detection from positive BC bottles: 5.9 × 105 CFU/ml Two washing steps added prior to the Sepsityper protocol |
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Buchan et al. | 2012 | [34] | Bactec Plus Aerobic/F and Bactec Lytic/10 |
45 97.7% genus 91.0% species |
100 80.0% genus 53% species |
5 0% genus |
150 85.5% genus 64.8% species |
>1.7 genus >2.0 species |
ID 24–130 h faster as compared to conventional methods Log(score) >1.7 was sufficient for ID on species level, since overall concordance to routine ID was 96.6% to genus and 94.1% to species level Five discrepant results: three Streptococcus oralis had Streptococcus pneumonia ID by MALDI; two were misidentified by conventional methods (16S sequencing confirmed MALDI) |
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Juiz et al. | 2012 | [43] | Bactec | 24 95.8% genus 95.8% species |
61 96.7% genus 84.7% species |
— | 85 96.4% genus 87.0% species |
>1.7 genus >2.0 species |
Sepsityper performed better than an alternative in-house method for sample preparation No correct ID of one Streptococcus pneumoniae |
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Klein et al. | 2012 | [35] | Bactec 9240 Bactec Plus Aerobic/F, Anaerobic/F, and Peds Plus/F |
52 99% species |
71 64% species |
— | 123 82.9% species |
>1.7 species (if matching organism stated several times in list) | Sepsityper performed better than alternative in-house method with gel separator tubes ID for Gram negative better than for Gram positive Misidentification of S. hominis instead of S. epidermidis and S. hominis instead of S. haemolyticus |
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Lagacé-Wiens et al. | 2012 | [36] | BacT/Alert SA BacT/Alert SN |
19 100% species |
40 80% species |
2 50% species |
61 85.2% species 88.5% if >1.5 |
>1.7 species >1.5 |
Log(score) >1.5 gave 100% concordance to routine ID Mean turnaround time for conventional ID was 40.9 h compared to 6.6 h for MALDI (if positive ID) |
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Loonen et al. | 2012 | [31] | BacT/Alert SA BacT/Alert SN |
47 95.7% genus 91.5% species |
52 65.4% genus 42.3% species |
— | 99 79.8% genus 65.7% species |
>1.7 genus >2.0 species |
Sepsityper performed better and was faster than two alternative sample preparation methods. Anaerobe BacT/Alert SN bottles lead to unreliable results, charcoal containing bottles not suitable |
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Martiny et al. | 2012 | [38] | Bactec Plus Aerobic Bactec F Lytic Anaerobic |
22 72.7% genus 59.1% species |
37 81.1% genus 74.3% species |
— | 59 78.0% genus 68.4% species |
>1.4 genus >1.6 species (if 0.3 difference to next in list) |
Relatively low number of BC tested. Gram positive bacteria resulted in better ID than Gram negative (unusual report, not confirmed by other studies). In direct comparison an in-house method performed better than Sepsityper. Log(score) cutoffs could be lowered to >1.6 for correct species ID, which increased the correct ID for both methods |
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Meex et al. | 2012 | [32] | BacT/Alert SN | 40 82.5% species |
67 58.2% species |
— | 107 67.3% species |
>1.8 species | Correct species ID accepted at any log(score), if first three database matches were identical No difference between Sepsityper and in-house method using saponin lysis ID of Salmonella paratyphi B only to genus level Direct ID faster than conventional method (1–24 h) |
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Saffert et al. | 2012 | [37] | Bactec 9240 Bactec Plus Aerobic/F Anaerobic/F Peds Plus/F |
35 94% genus 83% species |
64 80% genus 70% species |
— | 99 85% genus 75% species |
>1.5 genus >1.7 species |
Sepsityper and two in-house methods compared One Streptococcus viridans was identified as Streptococcus pneumoniae Log(score)s <1.5 in combination with Gram stain results would lead to another 9 correct ID |
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Chen et al. | 2013 | [33] | Bactec Plus Aerobic, Bactec F Lytic Anaerobic, and Bactec Myco Lytic | 106 99% genus 88.7% species |
75 96% genus 72% species |
— | 181 97.8% genus 81.8% species |
>1.6 genus >2.0 species |
Sepsityper used with Biotyper generated significantly more accurate identifications than with Vitek MS Only genus level ID in both systems for Salmonella spec. In 21 mixed cultures, correct double ID by Biotyper in 5 |
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Haigh et al. | 2013 | [28] | BacT/Alert 3D FA, BacT/Alert 3D PF, and BacT/Alert SN | 123 90% species |
168 64% species |
6 0% |
297 74% species |
>1.7 species | Most ID failures resulted from BC bottles with charcoal; therefore BacT/Alert bottles with charcoal are not the optimal culture medium in combination with Sepsityper |
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Jamal et al. | 2013 | [46] | Bactec 9240 or BacT/Alert | 53 66% species |
99 75,8% species |
8 50% species |
160 75.6% species |
>2.0 species | No data on genus identification shown. Definition of positive ID often independent of log(score). The term “misidentified” instead of “unidentified” was used for ID scores <1.5, 10 species not identified by routine method but MALDI |
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Nonnemann et al. | 2013 | [40] | Bactec FX | 53 88.7% genus 81% species |
148 60% genus 44% species |
22 77% species |
223 64% genus 56% species |
>1.6 genus >1.8 species |
The fungi experiments contained mainly spiked BC samples A lower cutoff (>1.5 for species ID) was also applied. Combined with Gram staining, a log(score) >1.3 increased Gram positive results to 85% without misidentifications |
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Tadros and Petrich | 2013 | [45] | Bactec Aerobic/F, Anaerobic/F, and Peds Plus/F | 19 94.7% genus 94.7% species |
60 93.3% genus 66.7% species |
1 100% genus 100% species |
80 93.8% genus 78% species |
>1.7 genus >2.0 species |
Some Gram positive specimens were excluded from species analysis Total number of samples contained also 7 cerebrospinal fluids spiked into BC bottles and 10 polymicrobial samples |
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Gorton et al. | 2014 | [42] | Bactec | — | — | 50 76% genus 56% species |
50 76% genus 56% species |
>1.6 genus >1.8 species |
100–200 cfu of yeast was spiked into BC bottles and after positive growth extracted by Sepsityper A lower log(score) (>1.5) for correct species ID and repeated measurements increased ID on species level to 84% Gram staining not sufficient for fungal ID! |
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Hazelton et al. | 2014 | [44] | Bactec Plus Aerobic/F, Lytic/10, Anaerobic/F, and Peds Plus/F | 64 98.4% species |
— | — | 64 98.4% species |
>2.0 species | Main focus of the study was the use of the Sepsityper kit for direct antibiotic resistance testing in the BD Phoenix system with 97.9% concordance in susceptibility testing |
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Martinez et al. | 2014 | [26] | VersaTREK Redox | 46 86.9% genus 80.4% species |
95 89.4% genus 81.0% species |
5 60% genus 60% species |
146 87.7% genus 80.1% species |
>1.6 genus >1.8 species |
Additional washing step added in protocol Anaerobic BC cultures excluded by design Also at least one correct ID in 77% of polymicrobial cultures Misidentification of 4 Streptococcus viridans specimens as S. pneumoniae |
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Schieffer et al. | 2014 | [27] | Bactec Plus Aerobic/F, Standard/10 Aerobic/F, Peds Plus/F, Lytic/10 Anaerobic/F, and VersaTREK Redox | 94 97.8% genus 95.7% species |
225 95.5% genus 81.7% species |
6 50% genus 16% species |
325 94.7% genus 84.0% species |
>1.6 genus >1.8 species |
Sepsityper was used in two hospitals; BC extraction on site; pellet was stored at RT until shipment, MALDI-TOF MS performed off site |
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Idelevich et al. | 2014 | [39] | Bactec 9240, Plus Aerobic/F, Plus Anaerobic/F, Mycosis-IC/F, and Peds Plus/F | — | — | 24 62.5% species |
24 62.5% species |
>1.5 species If first two results were identical |
Sepsityper protocol was followed without prior washing steps (compare to Yan et al. [41]). Manual shooting and double protein concentration for MALDI were tried out to increase log(score)s >1.7, Mean yeast for positive ID was 4.5 × 107. Results were 23.5 h earlier than standard method Sepsityper pellets generated antibiotic susceptibility profiles in 72.7% of samples 15 h earlier |