During the study period, a total of 52,130 specimens showed culture positivity, of which 9,872 (18.9%) contained WHO-PPL [7] pathogens. The highest number of WHO-PPL organisms were found in sputum (2,089/9,872), followed by nasopharyngeal swabs (2,015/9,872) and blood (1,156/9,872). A “high Priority” organism, Staphylococcus aureus, was the most commonly found (58.8%) WHO-PPL isolate. The other organisms showing high prevalence were Pseudomonas aeruginosa (19.0%) and Escherichia coli (13.7%), both of which belong to the “critical priority” group (Table 1).
In the late (2016–2021) phase, the percentage of resistance in “critical priority” pathogens was significantly higher (29.2% vs 47.2%), while the proportion was lower for the “high priority” isolates (65.6% vs 47.1%). However, no significant difference in the AMR% of "medium priority" organisms was observed between the two phases. (Fig. 1).
Table 1
World Health Organisation priority pathogen list (WHO-PPL) isolates collected from the Osaka University Hospital between January 1, 2010, and March 31, 2021
Specimen
|
Blood
|
Sterile body fluids
|
Other fluids
|
Urine
|
Stool
|
Sputum
|
NP swabs
|
Other swabs
|
Tissue
|
Fluids in the drain tube
|
Wound
|
Pus
|
GIT content
|
Equipment
|
Total
|
Critical priority isolates
|
Acinetobacter baumannii
|
3
(0.3)
|
0(0)
|
0(0)
|
2
(0.2)
|
0(0)
|
6
(0.3)
|
1(0)
|
0(0)
|
1
(0.2)
|
2
(0.8)
|
0(0)
|
0(0)
|
0(0)
|
1
(0.2)
|
16(0.2)
|
Pseudomonas aeruginosa
|
144
(12.5)
|
93
(31.3)
|
19
(10.2)
|
139
(14.5)
|
18
(8.5)
|
635
(30.4)
|
287
(14.2)
|
2
(2.9)
|
86
(17.5)
|
118
(45.7)
|
185
(16.6)
|
45
(9.8)
|
0(0)
|
106
(18.9)
|
1,877(19.0)
|
Enterobacteriaceae
|
Klebsiella pneumoniae
|
34
(2.9)
|
18
(6.1)
|
3
(1.6)
|
59
(6.2)
|
8
(3.8)
|
25
(1.2)
|
27
(1.3)
|
0(0)
|
5
(1.0)
|
15
(5.8)
|
32
(2.9)
|
6
(1.3)
|
1
(20.0)
|
21
(3.8)
|
254(2.6)
|
Escherichia coli
|
245
(21.2)
|
66
(22.2)
|
13
(7.0)
|
495
(51.7)
|
21
(9.9)
|
101
(4.8)
|
94
(4.7)
|
5
(7.1)
|
37
(7.5)
|
30
(11.6)
|
69
(6.2)
|
47
(10.2)
|
0
(0)
|
134
(23.9)
|
1,357(13.7)
|
Serratia spp.
|
0(0)
|
0(0)
|
0(0)
|
1(0.1)
|
0(0)
|
0(0)
|
3(0.1)
|
0(0)
|
1(0.2)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
5(0.1)
|
Proteus spp.
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
1(0.1)
|
1(0.2)
|
0(0)
|
0(0)
|
2(0)
|
Providencia spp.
|
1(0.1)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
1(0)
|
High priority isolates
|
Staphylococcus aureus
|
683 (59.1)
|
115 (38.7)
|
140 (74.9)
|
251 (26.2)
|
153 (72.2)
|
1,030 (49.3)
|
1,479 (73.4)
|
52
(74.3)
|
326 (66.3)
|
92
(35.7)
|
826
(74.1)
|
358
(77.8)
|
4
(80.0)
|
293
(52.3)
|
5,802(58.8)
|
Enterococcus faecium
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
6(2.8)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
2(0.4)
|
0(0)
|
0(0)
|
8(0.1)
|
Helicobacter pylori
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
3(0.6)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
3(0)
|
Campylobacter
|
10
(0.9)
|
0(0)
|
0(0)
|
0(0)
|
5(2.4)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
15(0.2)
|
Neisseria gonorrhoeae
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
2(2.9)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
0(0)
|
2(0)
|
Medium priority isolates
|
Haemophilus influenzae
|
9(0.8)
|
0(0)
|
2(1.1)
|
5(0.5)
|
1(0.5)
|
190(9.1)
|
59(2.9)
|
0(0)
|
14(2.8)
|
0(0)
|
1(0.1)
|
1(0.2)
|
0(0)
|
3(0.5)
|
285(2.9)
|
Streptococcus pneumoniae
|
27
(2.3)
|
5(1.7)
|
10(5.3)
|
5(0.5)
|
0(0)
|
102(4.9)
|
65(3.2)
|
9(12.9)
|
19(3.9)
|
1(0.4)
|
0(0)
|
0(0)
|
0(0)
|
2(0.4)
|
245(2.5)
|
Total isolates
|
1,156
|
297
|
187
|
957
|
212
|
2,089
|
2,015
|
70
|
492
|
258
|
1,114
|
460
|
5
|
560
|
9,872
|
NP, nasopharyngeal; GIT, gastrointestinal |
Among the “critical priority” organisms, a significantly higher proportion of resistance to carbapenem groups of antimicrobials was observed in Pseudomonas aeruginosa during the 2016-2021 phase. A higher proportion of resistance was also observed for 3rd generation cephalosporins in Escherichia coli and Klebsiella pneumoniae, with statistically significant value during the same phase. In the “High priority” group, the proportion of methicillin-resistant and vancomycin-intermediate Staphylococcus aureus was lower after 2015. Haemophilus influenzae, a “medium priority” pathogen, demonstrated higher ampicillin resistance in the late phase (Table 2).
Table 2: Percentage of resistance in World Health Organisation priority pathogen list (WHO-PPL) organisms to specific antimicrobials, collected from the Osaka University Hospital between January 1, 2010, and March 31, 2021.
|
Pathogen
|
2010–2015
|
2016–2021
|
All
|
P-Value
|
|
|
N = 6,374
|
N = 3,498
|
N = 9,872
|
|
Critical priority
|
Acinetobacter baumannii, CR
|
16(0.3)
|
0(0)
|
16(0.2)
|
0.003
|
Pseudomonas aeruginosa, CR
|
1,003(15.7)
|
874(25.0)
|
1,877(19.0)
|
< 0.001
|
Enterobacteriaceae
|
|
|
|
|
Klebsiella pneumoniae, 3GCR
|
101(1.6)
|
153(4.4)
|
254(2.6)
|
< 0.001
|
Escherichia coli, 3GCR
|
735(11.5)
|
622(17.8)
|
1,357(13.7)
|
< 0.001
|
Serratia spp., 3GCR
|
5(0.1)
|
0(0)
|
5(0.1)
|
0.098
|
Proteus spp., 3GCR
|
0(0)
|
2(0.1)
|
2(0)
|
0.056
|
Providencia spp., 3GCR
|
1(0)
|
0(0)
|
1(0)
|
0.459
|
High priority
|
Staphylococcus aureus, MR
|
3,890(61.0)
|
1,611(46.1)
|
5,501(55.7)
|
< 0.001
|
Enterococcus faecium, VR
|
6(0.1)
|
2(0.1)
|
8(0.1)
|
0.537
|
Staphylococcus aureus, VI
|
74(1.2)
|
2(0.1)
|
76(0.8)
|
< 0.001
|
Staphylococcus aureus, MR, VI
|
203(3.2)
|
22(0.6)
|
225(2.3)
|
< 0.001
|
Helicobacter pylori, ClaR
|
0(0)
|
3(0.1)
|
3(0)
|
0.019
|
Campylobacter, FQR
|
8(0.1)
|
7(0.2)
|
15(0.2)
|
0.363
|
Neisseria gonorrhoeae, FQR
|
0(0)
|
2(0.1)
|
2(0)
|
0.056
|
Medium priority
|
Streptococcus pneumoniae, PNS
|
182(2.9)
|
63(1.8)
|
245(2.5)
|
0.001
|
Haemophilus influenzae, AmpR
|
150(2.4)
|
135(3.9)
|
285(2.9)
|
< 0.001
|
CR, carbapenem-resistant; 3GCR, 3rd generation cephalosporin-resistant; MR, methicillin-resistant; VR, vancomycin-resistant; VI, vancomycin-intermediate; claR, clarithromycin-resistant; FQR, fluoroquinolone-resistant; PNS, penicillin-non-susceptible; AmpR, ampicillin-resistant
The cultures with the WHO priority organisms belonged to 1,601 patients. Of them, 969 (60.5%) were male subjects. Compared to the early phase, the frequency of chronic diseases such as hypertension, chronic kidney disease, diabetes, and cancer was lower in the late phase (Supplemental Table 1). However, there was no significant difference in in-hospital mortality between the two phases in patients with WHO-PPL resistance. (Supplemental Table 2).
Considering the clinical importance of “critical priority” resistance and the higher prevalence after 2015, other factors associated with this resistance and negative outcomes were further examined. Among non-chronic kidney disease (CKD) patients, there was no significant difference in in-hospital mortality between patients with and without "critical priority" AMR (4.7% vs 4.3%), while in patients with CKD (+), in-hospital mortality was significantly higher in "critical priority" AMR (+) than those without it (9.5% vs 1.3%) with an odds ratio of 8.140 (95% CI; 1.281–51.73). A significant interaction of 0.074 was observed for in-hospital mortality between AMR and the presence of CKD.
Additionally, among patients with no diabetes mellitus (DM), there was a trend toward lower in-hospital mortality in "critical priority" AMR (+) compared to "critical priority" AMR (-) (1.8% vs 4.1%). Whereas among diabetic patients, a significantly higher risk for in-hospital mortality was noticed in "critical priority" AMR (+) than those without it (13.3% vs 3.3%) with an odds ratio of 4.500 (95% CI; 1.404–14.422). There was also a significant interaction of 0.048 for in-hospital mortality between "critical priority" AMR and the presence of DM. (Fig. 2).
To assess the antimicrobial usage in Osaka University Hospital, we considered the antibiotics mentioned in the WHO-PPL. According to our data, carbapenems and antifungals were prescribed and used at significantly higher rates in hospitalized patients between 2016 and 2021. Contrarily, a lower proportion of usage was observed for 3rd generation cephalosporins in the late phase (Table 3).
Table 3
Antimicrobial use in Osaka University Hospital wards from January 1, 2010, to March 31, 2021
|
2010–2015
|
2016–2021
|
All
|
P-value
|
|
N = 41,772
|
N = 25,682
|
N = 67,454
|
|
Carbapenems usage (%)
|
2,838(6.8)
|
3,056(11.9)
|
5,894(8.7)
|
< 0.001
|
3rd generation cephalosporins usage (%)
|
4,978(11.9)
|
1,584(6.2)
|
65,62(9.7)
|
< 0.001
|
Antifungals usage (%)
|
4,546(10.9)
|
3,090(12.0)
|
7,636(11.3)
|
< 0.001
|
Other antimicrobials usage (%)
|
2,9410(70.4)
|
1,7952(69.9)
|
47,362(70.2)
|
0.164
|