Figure 1Study area comprising the 145 sampling points along the whole coastal region of South Korea.
Figure 2
Conventional PCR results of the amplification of the 16S rRNA gene.
Lane 9–13: clinical type and lanes 2, 3, and 5: environmental type of Vibrio vulnificus.
M = maker; NC = negative control; PC= positive control (237 and 825 bp), clinical type (237 bp) and environmental type (237 and 825 bp); PCR = polymerase chain reaction.
Table 1PCR amplification, and positive isolation of 3 pathogenic Vibrio species in the coastal seawater of South Korea from 2017 to 2018.
Year |
Target genes |
No. PCR positive samples |
PCR positive (%) |
No. bacterial isolates |
Positive isolation (%) |
No. total samples |
2017 |
hlyA
|
678 |
28.52 |
376 |
15.82 |
2,377 |
ctxA
|
0 |
0 |
0 |
0 |
vvhA
|
799 |
33.61 |
313 |
13.17 |
tlh
|
1,838 |
77.32 |
1,564 |
65.80 |
2018 |
hly
|
987 |
35.06 |
641 |
21.81 |
2,815 |
ctxA
|
0 |
0 |
0 |
0 |
vvh
|
1,213 |
43.09 |
546 |
19.40 |
tlh
|
2,107 |
74.85 |
1,972 |
70.05 |
Table 2Occurrence of septicemia cases and deaths caused by Vibrio vulnificus, during 2017 and 2018.
|
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
Total |
2017 |
0 |
0 |
0 |
1 |
0* (1)†
|
1 (1) |
2 |
13 (8) |
19 (11) |
9 (3) |
1 |
0 |
46 (24) |
2018 |
0 |
0 |
0 |
1 |
0 |
2 |
7 (3) |
16 (8) |
10 (6) |
11 (3) |
0 |
0 |
47 (20) |
Table 3Classification of Vibrio vulnificus seawater isolates based on tri-primer PCR amplification of 16S rRNA.
Year |
Environmental-type |
Clinical-type |
No. total isolates |
2017 |
4 |
81 |
313 |
2018 |
38 |
489 |
546 |
Table 4Monthly occurrence and distribution of pathogenic Vibrio species (detected by real-time PCR and colony isolation), from seawater samples collected at 145 points, from 35 coastal sites in South Korea during 2017.
Month |
No. of samples |
No. of sites |
No. of positives |
|
V. cholerae non-O1/non-O139 |
V. vulnificus
|
V. parahaemolyticus
|
|
|
|
PCR-positive |
Colony isolation |
PCR-positive |
Colony isolation |
PCR-positive |
Colony isolation |
Jan |
66 |
3 |
12 (18.18) |
2 (3.03) |
0 (0) |
0 (0) |
28 (42.42) |
20 (30.30) |
|
Feb |
70 |
3 |
13 (18.57) |
4 (5.71) |
0 (0) |
0 (0) |
27 (38.57) |
25 (35.71) |
|
Mar |
70 |
3 |
13 (18.57) |
10 (14.29) |
5 (7.14) |
1 (1.43) |
23 (32.86) |
17 (24.29) |
|
Apr |
290 |
13 |
38 (13.10) |
21 (7.24) |
21 (7.24) |
12 (4.14) |
130 (44.83) |
96 (33.10) |
|
May |
290 |
13 |
63 (21.65) |
35 (12.03) |
39 (13.40) |
16 (5.50) |
233 (80.07) |
196 (60.48) |
|
Jun |
290 |
13 |
81 (27.93) |
55 (18.97) |
79 (27.24) |
37 (12.76) |
263 (90.69) |
204 (70.34) |
|
Jul |
290 |
13 |
107 (36.90) |
66 (22.76) |
129 (44.48) |
56 (19.31) |
267 (92.07) |
223 (76.90) |
|
Aug |
290 |
13 |
133 (45.86) |
73 (25.17) |
193 (66.55) |
71 (24.48) |
272 (93.79) |
248 (85.52) |
|
Sep |
290 |
13 |
94 (32.87) |
50 (17.48) |
181 (63.29) |
66 (22.76) |
251 (87.76) |
238 (83.22) |
|
Oct |
290 |
13 |
90 (31.47) |
39 (13.64) |
136 (47.55) |
48 (16.55) |
244 (85.31) |
222 (77.62) |
|
Nov |
70 |
3 |
17 (25.76) |
12 (18.18) |
11 (16.67) |
6 (8.57) |
54 (81.82) |
50 (75.76) |
|
Dec |
70 |
3 |
17 (25.76) |
9 (13.64) |
5 (7.58) |
0 (0) |
46 (68.18) |
45 (69.70) |
Table 5Monthly occurrence and distribution of pathogenic Vibrio species as detected by real-time PCR and colony isolation from seawater samples collected at 145 points from 35 coastal sites in South Korea, 2018.
Month |
No. of samples |
No. of sites |
No. of positives |
|
V. cholerae non-O1/non-O139 |
V. vulnificus
|
V. parahaemolyticus
|
|
|
|
PCR-positive |
Colony isolation |
PCR-positive |
Colony isolation |
PCR-positive |
Colony isolation |
Jan |
70 |
3 |
19 (27.14) |
13 (18.57) |
2 (2.86) |
0 (0) |
31 (44.29) |
29 (41.43) |
|
Feb |
70 |
3 |
12 (17.14) |
9 (12.86) |
2 (2.86) |
0 (0) |
19 (27.14) |
16 (22.86) |
|
Mar |
70 |
3 |
20 (28.57) |
16 (22.86) |
5 (7.14) |
1 (1.43) |
20 (28.57) |
20 (28.57) |
|
Apr |
290 |
13 |
52 (17.93) |
36 (12.41) |
26 (8.97) |
12 (4.14) |
80 (27.59) |
74 (25.52) |
|
May |
290 |
13 |
66 (22.76) |
41 (14.14) |
40 (13.79) |
14 (4.83) |
169 (58.28) |
147 (50.69) |
|
Jun |
290 |
13 |
95 (32.76) |
64 (22.07) |
101 (34.83) |
28 (9.66) |
244 (84.14) |
218 (75.17) |
|
Jul |
290 |
13 |
150 (51.72) |
87 (30.0) |
182 (62.76) |
71 (24.48) |
252 (86.90) |
231 (79.66) |
|
Aug |
290 |
13 |
343 (47.31) |
229 (21.38) |
465 (64.14) |
194 (26.76) |
658 (90.76) |
619 (85.38) |
|
Sep |
290 |
13 |
125 (43.10) |
62 (21.38) |
217 (74.83) |
133 (45.86) |
280 (96.55) |
273 (94.14) |
|
Oct |
290 |
13 |
80 (27.59) |
44 (15.17) |
156 (53.79) |
85 (29.31) |
261 (90.00) |
254 (87.59) |
|
Nov |
70 |
3 |
13 (8.57) |
8 (11.43) |
12 (17.14) |
5 (7.14) |
53 (75.71) |
52 (74.29) |
|
Dec |
70 |
3 |
12 (17.14) |
5 (7.14) |
5 (7.14) |
3 (4.29) |
40 (57.14) |
39 (55.71) |