We aimed to determine characteristics of host, causative organisms, and antibiotic susceptibility of bacteria in pediatric patients with UTI living in metropolitan area of Korea.
Retrospective investigation was done for the causative organisms of UTI in 683 pediatric cases treated at Ajou University Hospital from 2012 to 2017. Patients were classified into
A total of 683 UTIs occurred in 550 patients, of which 463 (67.8%) were first-time infection and 87 (32.2%) were recurrent ones (2–7 recurrences, 2.52 average), and 64.9% were male and 35.1% were female. The most common causative organism was
New treatment guideline should be considered due to the incidence of ESBL(+)
Urinary tract infection (UTI) is one of the most common bacterial infections in children. It is the most common cause of fever without focus in infants younger than two years of age. It accounts for 5–14% of pediatric emergency room visits [
A total 683 pediatric patients aged below 15 years treated for UTI from January 2012 to December 2017 were included in this study. Patients were divided into five age groups (<6 months, 6–12 months, 12–24 months, 24–60, and ≥60 months). Pathogenic strains were grouped as
UTI was confirmed by body temperature greater than 38℃ using a tympanic thermometer, urine leukocytes of more than 10 per high power field view on microscopy, and colony count of pathogen at more than 105 colonies/mL of single organism on urine culture study. When two or more strains were cultured, the cases were excluded from this study [
Urine was collected in a sterilized urine bag or plastic cup after cleaning the urethral orifice area with 2% boric acid. For microscopic examination, urine samples were centrifuged and Gram stained to observe urinary bacteria and leukocytes. For culture study, 0.001 mL urine was inoculated into blood agar medium and MacConkey agar medium separately and incubated at 37℃ for 18–24 hours. The number of bacterial colonies per 1 mL was then calculated [
The antibiotic resistance of
Collected data were analyzed using SPSS 18.0 program. Differences according to gender and age groups were evaluated using Chi-square and t tests. In order to evaluate the difference in incidences among the age groups, goodness of fit was determined by Chi-square test, and cross-tabulation analysis was done to establish significant differences in the incidence of UTI, by gender among the age groups. Statistical significance was considered when
Among 683 cases, 443 (64.9%) were male and 240 (35.1%) were female. Patients’ age less than 6 months accounted for the majority (n=335, 49%), followed by 6–12 months (n=192, 28%), 12–24 months (n=53, 7.8%), 24–60 months (n=50, 7.4%) and ≥60 months (n=53, 7.8%). Thus, 77.2% of childhood UTI developed at the age under 24 months. The incidence of UTI in age <6 months group was significantly higher than others (
Incidence of
Among a total of 527
A total of 126 ESBL(+)
Over a six year-period from January 2012 to December 2017, the occurrence of ESBL(+) E.coli case has increased from 25.0% in 2012 to 31.9% in 2017. However, its incidence was not significantly different during these years (
As a result, the resistance rate of ampicillin was 71.7% and that of amoxicillin/clavulanic acid was 33.6%. Resistance rates against third- and fourth- generation cephalosporin were 23–26%. Resistance rate to ertapenem, imipenem, and tigecycline was 0.0%. Antibiotic resistance rates of ESBL(+)
Among 550 patients, ESBL(+) was identified in 146 (26.5%). Among these, 126 were
No significant statistical differences were found in the distribution of the severity of vesico-ureteral reflux (VUR) between recurrent (n=87) and non-recurrent UTI groups (n=463) (
Among the 683 pediatric cases diagnosed with UTI at our institute from 2012 to 2017, 64.9% were male and 35.1% were female. This is similar to previous studies showing a higher prevalence in male children including neonatal period, and higher incidence in females after childhood, except for those aged above 50 years [
Several investigators have reported that pathogens of UTI are mainly enterobacteria, including
We investigated the frequency of ESBL-producing ESBL(+)
In this study, antibiotics with resistance rates below 10% were amikacin, cefoxitin, ertapenem, imipenem, piperacillin/tazobactam, tigecycline, and nitrofurantoin. Third- and fourth- generation cephalosporin such as cefepime (23.7%) and cefotaxime (26.9%) showed relatively low resistance rates, whereas ESBL(+)
Nationally, the common regime for UTI treatment is to give empirical antibiotics firstly right after diagnosis, and to discharge the patient or schedule the next visit, if there are apparent clinical improvements for a few days. After completing two weeks of antibiotics administration, the patient will come and receive tests for confirming successful treatment. At times, the patient is informed late that he or she had ESBL(+) bacterial infection, even though the final follow-up tests are normal: no clinical sign, urine culture negative, and no pyuria. For such cases, we should pay close attention to prevent incomplete treatment or recurrence of UTI.
Throughout the current cases, the recurrence rate of UTI between ESBL(+) and ESBL(-) patients showed no significant difference (
In Korea, antibiotics are occasionally prescribed for treating simple pediatric febrile illnesses at primary care institutions, and this may lead to increases in antibiotic resistance of bacteria and also to more serious renal damage, due to delayed or incomplete treatment in those misdiagnosed UTI as simple pharyngitis or acute otitis media. It was acknowledged that susceptibility of
Choosing antibiotics for UTI treatment will become more difficult as the incidence of ESBL(+) E.coli is becoming more common. The success rate of primary treatment with empirical antibiotics will be lowered, and, the renal damages will be more serious.
The number of research subjects was much reduced, because this study included single bacterium cultured cases exclusively. In order to obtain more accurate and useful information for UTI treatment, additional researches should be done through extension of research period and expansion of inclusion range of patients.
This study was approved by the institutional review board (IRB), and the consent was waived due to the nature of the retrospective study [IRB number MED-MDB-18-342].
No potential conflict of interest relevant to this article was reported.
Annual number of patients with ESBL-producing
Age and Gender Distribution of Children with UTI in an Urban Area of Korea (2012–2017)
Age in months | Gender |
Number (%) | |
---|---|---|---|
Male | Female | ||
<6 | 254 (75.8) | 81 (24.2) | 335 (49.0) |
6–12 | 118 (61.5) | 74 (38.5) | 192 (28.1) |
12–24 | 34 (64.2) | 19 (35.8) | 53 (7.8) |
24–60 | 12 (24.0) | 38 (76.0) | 50 (7.3) |
≥60 | 25 (47.2) | 28 (52.8) | 53 (7.8) |
Total | 443 (64.9) | 240 (35.1) | 683 (100.0) |
Abbreviation: UTI, urinary tract infection.
Identification of Pathogenic Strains in Children with UTI (2012–2017)
Gram stain | Strains | Number of patients (%) |
---|---|---|
Gram (-) | 527 (77.2) | |
73 (10.7) | ||
|
10 (1.5) | |
|
2 (0.3) | |
|
61 (8.9) | |
27 (4.0) | ||
|
17 (2.5) | |
|
10 (1.5) | |
11 (1.6) | ||
1 (0.1) | ||
8 (1.2) | ||
2 (0.3) | ||
10 (1.4) | ||
3 (0.4) | ||
2 (0.3) | ||
2 (0.3) | ||
2 (0.3) | ||
1 (0.1) | ||
1 (0.1) | ||
Gram (+) | 5 (0.8) | |
|
4 (0.7) | |
|
1 (0.1) | |
12 (1.8) | ||
|
1 (0.1) | |
|
5 (0.8) | |
|
6 (0.9) | |
7 (0.9) | ||
|
3 (0.4) | |
|
1 (0.1) | |
|
3 (0.4) |
Abbreviation: UTI, urinary tract infection.
Incidence of Pathogenic Strains of UTI according to Age of Patients (2012–2017)
Gram stain | Pathogens | Number of patients (%) |
||||
---|---|---|---|---|---|---|
<6 mo. | 6–12mo. | 12–24 mo. | 24–60mo. | ≥60 mo. | ||
Gram (-) | 265 (79.3) | 145 (75.9) | 38 (73.1) | 42 (84.0) | 37 (69.8) | |
29 (8.7) | 29 (15.2) | 4 (7.7) | 2 (4.0) | 9 (17.0) | ||
21 (6.3) | 5 (2.6) | 0 (0.0) | 1 (2.0) | 0 (0.0) | ||
3 (0.9) | 5 (2.6) | 3 (5.8) | 0 (0.0) | 0 (0.0) | ||
0 (0.0) | 2 (1.0) | 4 (7.7) | 3 (6.0) | 1 (1.9) | ||
0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 3 (5.7) | ||
0 (0.0) | 0 (0.0) | 1 (1.9) | 0 (0.0) | 1 (1.9) | ||
1 (0.3) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (1.9) | ||
1 (0.3) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | ||
Gram (+) | 7 (2.1) | 2 (1.0) | 1 (1.9) | 1 (2.0) | 1 (1.9) | |
2 (0.6) | 1 (0.5) | 1 (1.9) | 1 (2.0) | 0 (0.0) | ||
5 (1.5) | 2 (1.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | ||
Total (100) | 334 (49.1) | 191 (28.1) | 52 (7.6) | 50 (7.4) | 53 (7.8) |
Abbreviation: UTI, urinary tract infection.
Incidence of
Non- |
N (%) | ||||
---|---|---|---|---|---|
Sex | Male | 341 (77.0) | 102 (33.0) | 443 (100.0) | 0.876 |
Female | 186 (77.5) | 54 (22.5) | 240 (100.0) | ||
Total | 527 (77.2) | 156 (22.8) | 683 (100.0) | ||
Age in month | <6 | 265 (79.1) | 70 (20.9) | 335 (100.0) | 0.302 |
6–12 | 145 (75.5) | 47 (24.5) | 192 (100.0) | ||
12–24 | 38 (71.7) | 15 (28.3) | 53 (100.0) | ||
24–60 | 42 (84.0) | 8 (16.0) | 50 (100.0) | ||
≥60 | 37 (69.8) | 16 (30.2) | 53 (100.0) | ||
Total | 527 (77.2) | 156 (22.8) | 683 (100.0) |
Abbreviation: UTI, urinary tract infection.
Incidence of ESBL-producing
ESBL(+) |
ESBL(-) |
N (%) | |||
---|---|---|---|---|---|
Sex | Male | 89 (26.1) | 252 (73.9) | 341 (100.0) | 0.110 |
Female | 37 (19.9) | 149 (80.1) | 186 (100.0) | ||
Total | 126 (23.9) | 401 (76.1) | 527 (100.0) | ||
Age in month | <6 | 60 (22.6) | 205 (77.4) | 265 (100.0) | 0.100 |
6–12 | 36 (24.8) | 109 (75.2) | 145 (100.0) | ||
12–24 | 14 (36.8) | 24 (63.2) | 38 (100.0) | ||
24–60 | 12 (28.6) | 30 (71.4) | 42 (100.0) | ||
≥60 | 4 (10.8) | 33 (89.2) | 37 (100.0) | ||
Total | 126 (100.0) | 401 (100.0) | 527 (100.0) |
Abbreviation: UTI, urinary tract infection; ESBL, extended spectrum betalactamase.
Annual Incidence of ESBL-producing
2012 | 2013 | 2014 | 2015 | 2016 | 2017 | |
---|---|---|---|---|---|---|
ESBL(+) | 5 | 22 | 12 | 16 | 25 | 46 |
n=126 | (25.0) | (26.2) | (21.4) | (18.8) | (18.1) | (31.9) |
ESBL(-) | 15 | 62 | 44 | 69 | 113 | 98 |
n=401 | (75.0) | (73.8) | (78.6) | (81.2) | (81.9) | (68.1) |
N=527 | 20 | 84 | 56 | 85 | 138 | 144 |
(100.0) | (3.8) | (16.0) | (10.6) | (16.1) | (26.2) | (27.3) |
Abbreviations: UTI, urinary tract infection; ESBL, extended spectrum betalactamase.
Comparison of Antibiotic Resistances of
Antibiotics | Resistance (%) |
||
---|---|---|---|
General |
ESBL(+) |
||
AMIKACIN | 0.2 | 0.8 | 0.086 |
AMOX/CLAVULANIC ACID |
33.6 | 49.2 | <0.001 |
AMPICILLIN | 71.7 | 100.0 | <0.001 |
AZTREONAM | 23.9 | 99.2 | <0.001 |
CEFAZOLIN | 31.1 | 99.2 | <0.001 |
CEFEPIME | 23.7 | 99.2 | <0.001 |
CEFOTAXIME | 26.9 | 99.2 | <0.001 |
CEFOXITIN | 7.0 | 12.7 | <0.001 |
CEFTAZIDIME | 25.4 | 99.2 | <0.001 |
CIPROFLOXACIN | 23.5 | 38.1 | <0.001 |
ERTAPENEM | 0.0 | 0.0 | NS |
GENTAMICIN | 24.9 | 44.4 | <0.001 |
IMIPENEM | 0.0 | 0.0 | NS |
PIPERACILLIN/TAZOBACTAM | 9.9 | 16.7 | <0.001 |
PIPERACILLIN | 69.2 | 100.0 | <0.001 |
TETRACYCLINE | 30.8 | 25.0 | <0.001 |
TIGECYCLINE | 0.0 | 0.0 | <0.001 |
NITROFURANTOIN | 7.7 | 0.0 | 0.004 |
NORFLOXACIN | 23.1 | 25.0 | <0.001 |
Abbreviations: ESBL(+), extended spectrum beta-lactamase producing; The general
AMOXICILLIN/CLAVULANIC ACID.
Incidence of ESBL(+) Pathogens according to the Recurrence Frequency of UTI (2012–2017)
Number of UTI attacks | ESBL producibility of pathogens |
||
---|---|---|---|
ESBL (+) | ESBL (-) | Subtotal | |
1 | 113 (24.4) | 350 (75.6) | 463 (84.2) |
2 | 22 (36.7) | 38 (63.3) | 60 (10.9) |
3 | 6 (33.3) | 12 (66.7) | 18 (3.3) |
4 | 2 (66.7) | 1 (33.3) | 3 (0.5) |
5 | 2 (66.7) | 1 (33.3) | 3 (0.5) |
6 | 1 (50.0) | 1 (50.0) | 2 (0.4) |
7 | 0 (0.0) | 1 (100.0) | 1 (0.2) |
Total | 146 (26.5) | 404 (73.5) | 550 (100.0) |
Abbreviations: UTI, urinary tract infection; ESBL, extended spectrum beta-lactamase; Numbers in parentheses are percentages; ESBL(+) strains include both 126 of
Incidence and Severity of VUR according to the Recurrence of Infections in Children with UTI (2012–2017)
VUR Grade | UTI Occurrence |
||
---|---|---|---|
Non-recurrent | Recurrent | ||
No data | 233 | 13 | 0.194 |
0 | 153 | 40 | 0.002 |
1 | 12 | 2 | |
2 | 24 | 11 | |
3 | 24 | 11 | |
4 | 9 | 7 | |
5 | 8 | 3 | |
Total | 463 | 87 |
Abbreviations: VUR, vesico-ureteral reflux; UTI, urinary tract infection; No data means the corresponding patients had not received VUR study.
Comparison between Severity of VUR and ESBL Producing by Pathogens in 87 Patients with Recurrent UTI
VUR Grade | ESBL producing |
||
---|---|---|---|
ESBL (+) | ESBL (-) | ||
No data | 5 | 8 | 0.477 |
0 | 18 | 22 | |
1 | 0 | 2 | |
2 | 3 | 8 | |
3 | 4 | 7 | |
4 | 3 | 4 | |
5 | 0 | 3 | |
Total | 33 | 54 |
Abbreviations: VUR, vesico-ureteral reflux; ESBL, extended spectrum beta-lactamase; UTI, urinary tract infection; No data means the corresponding patients had not received VUR study.