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. 2023 Jul 14;85(9):880–894. doi: 10.1292/jvms.23-0180

Table 2. Summary of representative findings of exposure bioassays using the in vitro rearing of Apis mellifera larvaea.

Reference Strain (typical/atypical) Genotypeb
 pMP19 possession at the time of the experimentc Country of origin Age of larvae at the start of the inoculation Infection dosed Observation period Mortality of larvae at the end of the experiment
ST CC
[4] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 5 days 8.6%
DAT606 (typical) 3 3 Probably − Japan <24 hr old approx. 5.0 × 104 CFU/larva 5 days 5.7%
DAT583 (typical) 3 3 Probably − Japan <24 hr old approx. 5.0 × 104 CFU/larva 5 days 12.5%
DAT585 (typical) 26 13 − Japan <24 hr old approx. 5.0 × 104 CFU/larva 5 days 16.7%
DAT561 (atypical) 12 12 Probably − Japan <24 hr old approx. 5.0 × 104 CFU/larva 5 days 94.3%
DAT351 (atypical) 12 12 − Japan <24 hr old approx. 5.0 × 104 CFU/larva 5 days 91.7%
DAT573 (atypical) 12 12 Probably − Japan <24 hr old approx. 5.0 × 104 CFU/larva 5 days 70.8%
[77] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 5 days 0%
DAT561 (atypical) 12 12 NI Japan <24 hr old approx. 1.0 × 105 CFU/larva 5 days 83.3%
[45] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 6 days 2.9–11.1%
21 days 8.6%
DAT606 (typical) 3 3 Probably + Japan <24 hr old 6.0 × 103 CFU/larva 6 days 63.3%
5.7 × 103 CFU/larva 21 days 100%
DAT585 (typical) 26 13 − Japan <24 hr old 3.6 × 104 CFU/larva 6 days 7.1%
2.5 × 103 CFU/larva 21 days 17.1%
DAT561 (atypical) 12 12 Probably + Japan <24 hr old 6.7 × 103 CFU/larva 6 days 96.7%
2.8 × 103 CFU/larva 21 days 100%
[43] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 21 days 5.3–19.4%
DAT606 (typical) 3 3 + Japan approx. 48–72 hr old 6.6 × 102 −9.0 × 104 CFU/larva 21 days 55.3–97.5%
− 2.0 × 102 −1.4 × 105 CFU/larva 0–35.0%
DAT639 (typical) 3 3 + Japan approx. 48–72 hr old 7.6 × 103 CFU/larva 21 days 85.7%
− 1.52 × 104 CFU/larva 5.6%
DAT869 (typical) 4 13 + Japan approx. 48–72 hr old 8.0 × 103 CFU/larva 21 days 10.0%
− 1.28 × 105 CFU/larva 10.0%
DAT561 (atypical) 12 12 + Japan approx. 48–72 hr old 1.92 × 105 CFU/larva 21 days 100%
− 1.94 × 105 CFU/larva 87.5%
[44] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 21 days ≤14.6%
DAT561 (atypical) 12 12 − Japan approx. 48–72 hr old 2.2–4.6 × 104 CFU/larva 21 days 77.1–80.6%
[55] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 14 days approx. 15%e
119 (typical) 20 13 − Switzerland 5–10 hr old ~6.0 × 104 CFU/larva 14 days approx. 67%e
[40] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 12 days approx. 24–41%?f
49.3 (typical) 3 3 Probably + Switzerland <24 hr old 1.21 × 103 ± 398 CFU/larva 12 days approx. 89–98%f
3.46 × 104 ± 1.57 × 104 CFU/larva 14 days approx. 50%f
119 (typical) 20 13 − Switzerland <24 hr old 797 ± 380 CFU/larva 12 days approx. 58–64%?f
4–127 (typical) 1 13 NI Sweden <24 hr old 1.75 × 104 ± 8.42 × 103 CFU/larva 12 days approx. 58–80%f
[34] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 21 days 17.98–21.25%
UK 31.1 (typical) 13 13 − England <24 hr old 1 × 105 CFU/larva 21 days 4.67%g
CH 82 (typical) 32 13 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 6.80%g
FR 27.1 (typical) 20 13 − France <24 hr old 1 × 105 CFU/larva 21 days 16.46%g
CH 90 (typical) 13 13 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 22.55%g
CH 119 (typical) 20 13 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 28.28%g
CH 54.1 (typical) 35 13 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 32.82%g
CH 40.2 (typical) 35 13 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 43.97%g
UK 36.1 (typical) 3 3 − England <24 hr old 1 × 105 CFU/larva 21 days 1.24%g
IT 1.3 (typical) 3 3 − Italy <24 hr old 1 × 105 CFU/larva 21 days 7.43%g
CH 46.1 (typical) 7 3 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 39.44%g
CH 45.1 (typical) 3 3 − Switzerland <24 hr old 1 × 105 CFU/larva 21 days 42.93%g
NO 764-5B (typical) 3 3 − Norway <24 hr old 1 × 105 CFU/larva 21 days 48.74%g
NO 765-6B (typical) 3 3 − Norway <24 hr old 1 × 105 CFU/larva 21 days 53.50%g
CH 49.3 (typical) 3 3 + Switzerland <24 hr old 1 × 105 CFU/larva 21 days 79.98%g
− 5.88%g
CH 21.1 (typical) 7 3 + Switzerland <24 hr old 1 × 105 CFU/larva 21 days 84.85%g
CH 60 (typical) 7 3 + Switzerland <24 hr old 1 × 105 CFU/larva 21 days 91.88%g
[53] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 21 days approx. 6–20%h
CH 49.3 (typical) 3 3 Probably + Switzerland <24 hr old 3.42 × 104 ± 1.28 × 104 CFU/larva 21 days approx. 69%h
4.44 × 104 ± 1.02 × 104 CFU/larva approx. 90%h
CH 45.1 (typical) 3 3 − Switzerland <24 hr old 1.79 × 104 ± 1.77 × 104 CFU/larva 21 days approx. 59%h
[76] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 6 days approx. 3–6%i
2019BC1 (atypical) 19 12 NI Canada <24 hr old 50 CFU/larva 6 days approx. 26–50%i
250 CFU/larva approx. 73–95%i
500 CFU/larva approx. 88–99%i
[41] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 6 days 8–18%
2019BC1 (atypical) 19 12 NI Canada <24 hr old 50 CFU/larva 6 days 56–78%
[69] No infection control N/A N/A N/A N/A N/A 0 CFU/larva 6 days 0–16.7%j
BC (atypical) 19 12 NI Canada <24 hr old ~100 CFU/larva 6 days 41.7–66.7%j
AB (atypical) 19 12 NI Canada <24 hr old ~100 CFU/larva 6 days 58.3–91.7%j
SK (atypical) 36 12 NI Canada <24 hr old ~100 CFU/larva 6 days 8.3–100%j

a Representative findings of previous studies where the genotype of the M. plutonius strain used was specified or known from other papers were summarized. N/A, not applicable. b ST, sequence type; CC, clonal complex. Some of the typing results are unpublished observations of Takamatsu et al. c +, The strain possessed pMP19 at the time of the experiment; -, The strain did not possess pMP19 at the time of the experiment; NI, no information. d CFU, colony forming unit. e Since the exact value of the mortality rate was not stated in the reference [55], the approximate value was read from the graphs in Figure 3 in the reference [55]. f Since the exact value of the mortality rate was not stated in the reference [40], the approximate value was read from the graphs in Figures 1 and 2 in the reference [40]. g Henderson-Tilton corrected mortality calculated by the following formula: 1- ((number of live test bees after treatment * number of live control bees after treatment−1) * (number of live control bees before treatment * number of live bees before treatment−1)) [34]. h Since the exact value of the mortality rate was not stated in the reference [53], the approximate value was read from the graphs in Fig 2 (pre-exposure and non-exposed conditions; for the no infection control and CH 49.3) and Fig 4 (non-exposed conditions; for the no infection control and CH 45.1) in the reference [53]. i Since the exact value of the mortality rate was not stated in the reference [76], the approximate value was read from the graphs in Figure 2 in the reference [76]. j Mortalities were calculated using data shown in Table S1 in the reference [69].