J Infect Chemother 21 (2015) 31e33
Contents lists available at ScienceDirect
Journal of Infection and Chemotherapy journal homepage: http://www.elsevier.com/locate/jic
Original article
Do patients who complain of lower urinary tract symptoms frequently have clinically significant pyuria? Satoshi Takahashi*, Koji Ichihara, Yoshiki Hiyama, Teruhisa Uehara, Jiro Hashimoto, Naoya Masumori Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo 060-8543, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 16 June 2014 Received in revised form 26 July 2014 Accepted 22 August 2014 Available online 12 September 2014
There is still controversy about whether post-void residual (PVR) urine volume affects the onset of urinary tract infection (UTI). In addition, although male patients with lower urinary tract symptoms (LUTS) might potentially have PVR, the association between LUTS and UTI or asymptomatic pyuria with or without bacteriuria remains unclear. We studied the frequency of asymptomatic pyuria, with and without bacteriuria, in patients with LUTS without a previous history of urinary tract manipulation at the first visit and their sequential courses. This retrospective study was done by reviewing medical charts. A total of 453 male patients who complained of LUTS and visited our outpatient clinic in 2008 were included in this study. The frequency of pyuria, with or without bacteriuria, in this study at the first visit was 4.9%. The median PVR volumes at the initial examination were 79 ml in the 22 patients with pyuria and 22 ml in the 431 patients without pyuria. The difference of the PVR volume between the patients with pyuria and those without pyuria was statistically significant (p ¼ 0.0095). Twelve patients were treated with alpha-blockers without antimicrobial chemotherapy and pyuria disappeared in 5 (41.7%) of them. However, the decrease in the rate of PVR was not significantly different between the patients with persisting pyuria and those without pyuria. A not negligible number of patients with LUTS had pyuria at the first visit; however, there was no febrile UTI in their clinical course even if they received no urological manipulation. © 2014, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Keywords: Urinary tract infection Pyuria Post-void residual Lower urinary tract symptoms
1. Introduction Several studies [1,2] showed positive correlations between significant post-void residual (PVR) urine volume and urinary tract infection (UTI), whereas other studies [3,4] reported that there was no relation between them. In an experimental study [5], significant PVR led to the urinary bacterial count being higher than in normal residual urine. In the clinical situation, the question of whether PVR affects the onset of UTI remains controversial. A study on patients with benign prostatic hyperplasia (BPH) [6] showed that manipulation of the urinary tract during follow-up was likely to lead to UTI in patients with considerable PVR. Some patients with lower urinary tract symptoms (LUTS) fail to completely void urine and this can lead to some degree of PVR. * Corresponding author. Department of Urology, Sapporo Medical University School of Medicine, S1, W16, Chuo-ku, Sapporo 060-8543, Japan. Tel.: þ81 11 611 2111x3472; fax: þ81 11 612 2709. E-mail addresses: [email protected], [email protected] (S. Takahashi).
When patients with LUTS have considerable PVR at the first visit to a urologic clinic, the association between LUTS with/without considerable PVR and UTI is unclear. However, if patients with asymptomatic bacteriuria undergo urinary tract manipulation without any antimicrobial prophylaxis, febrile UTI can develop. Therefore, we studied the frequency of pyuria and the clinical courses of male patients with LUTS without a previous history of urinary tract manipulation. Especially, we focused the clinical course in the patients with pyuria at the first visit. 2. Material and methods This retrospective study was done by reviewing medical charts. The male patients who complained of LUTS and first visited the outpatient clinic in Sapporo Medical University Hospital from January through December 2008 were included in this study. The patients who underwent urethral manipulation within the previous 1 month, e.g., urethral catheterization or cystoscopic examination, or were clinically diagnosed as having male urethritis or
http://dx.doi.org/10.1016/j.jiac.2014.08.022 1341-321X/© 2014, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
32
S. Takahashi et al. / J Infect Chemother 21 (2015) 31e33
prostate cancer, and those treated with antimicrobial agents within 1 month, with a previous history of urinary retention, or who underwent transurethral prostatic surgery, and those whose PVR was not determined at the initial visit were excluded from this study. As a strict definition of male urethritis, urethral or micturitional pain was necessary for diagnosis. The patients who complained of such pain and received antimicrobial agents at the first visit were also excluded from this study. At the first visit, a basic examination including an interview, abdominal and digital rectal examinations, urinalysis, uroflowmetry and measurement of PVR was performed. When the patients continued to visit the clinic thereafter, the data from the examination at each visit were evaluated if possible. The intervals between visits were sometimes irregular due to the retrospective nature of the study. The follow-up period was defined as that from the day of the first visit to that of the last visit noted in the medical chart. Throughout the clinical course, certified urologists checked the data and made diagnoses. PVR was determined as the maximum volume determined by transabdominal ultrasound using a BladderScan BVI3000 (Sysmex Co. Kobe, Japan) postvoiding. Urinalysis was done using midstream urine and pyuria in this study was defined as 5 or more white blood cells (WBC) per high power field (hpf) microscopically with or without bacteriuria. Bacteriuria was defined as an isolated bacterial count of 105 colonyforming units (CFU)/ml or more. Statistical analysis was done using the ManneWhitney test, chisquare test and KruskaleWallis test for the relation between PVR and UTI. The median volume of PVR is presented as the volume and its range. The average volume is presented as the volume and its standard deviation. The details of this research project were approved the Review Board in Sapporo Medical University Hospital (http://web.sapmed.ac.jp/byoin/chiken/irb.html) (No. 25-115). This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) (http://www. umin.ac.jp/ctr/index.htm) (UMIN ID: UMIN000011632). 3. Results Altogether, 453 patients were included in this study. Their median age was 69 (36e93) years. The median volume of PVR was 25 (0e500) ml. Twenty-two (4.9%) of the 453 had pyuria. Urine culture was done for 10 of these 22 patients and bacterial strains were isolated from 7 of them. The isolated bacterial strains were Enterococcus faecalis in 2, Staphylococcus haemolyticus in 2, Escherichia coli in 1, Staphylococcus epidermidis in 1, and Corynebacterium striatum in 1. In 12 patients without applying urine culture, the microscopic findings showed positive bacteriuria in 5 patients and negative bacteriuria in 7 patients. Therefore, there were 12 (54.5%) of these 22 patients with any degree of bacteriuria. The median PVR volumes at the initial examination were 79 ml in the 22 patients with pyuria and 22 ml in the 431 patients without Table 1 Patients' characteristics between those with pyuria and those without pyuria. Factors
Patients with pyuria
Patients without pyuria
Number Median age (range) Median PVR (ml) (range) Diagnosis BPH Neurogenic bladder Others
22 71 (58e88) 79 (0e438)
431 69 (36e93) 22 (0e500)
19 (86.3%) 2 (9.1%) 1 (4.5%)
354 (82.1%) 53 (12.3%) 24 (5.6%)
PVR; post-void residual. BPH; benign prostatic hypertrophy. a ManneWhitney test. b Chi-square test.
p Value
0.2054a 0.0095a 0.8692b
Table 2 The association between the 3 groups of PVR volume and the frequency of pyuria. PVR volume (ml)
Number of patients with pyuria
Number of patients without pyuria
PVR < 50 50 & PVR < 100 100 & PVR
8 (2.8%) 6 (8.2%) 8 (8.3%)
276 (97.2%) 67 (91.8%) 88 (91.7)
pyuria. The difference in the PVR volume between the patients with and without pyuria was statistically significant (p ¼ 0.0095) (Table 1). When the PVR volume was divided into 3 groups (less than 50 ml, 50e100 ml, and more than 100 ml), the frequency of pyuria was higher in the groups with PVR of 50 ml or more than that in the group with PVR of less than 50 ml (p ¼ 0.0100) (Table 2). We then tried to clarify the cutoff value to predict UTI but we could not determine it. However, if PVR of 180 ml [1] was used as the cutoff value, the sensitivity was 8.6% and specificity was 95.5%. For the 22 patients with pyuria at the first visit, the average follow-up period was 13.5 (±13.3) months. During the follow-up period, no febrile UTI event occurred. Of these patients, 16 with LUTS/BPH received alpha 1 adrenergic receptor blockade (alphablocker treatment) and were analyzed during the follow-up period after the first visit. During follow-up, 4 of these16 patients were treated with antimicrobial agents and pyuria had disappeared in 3 of the 4 at the last visit. In these 3 patients, the average initial PVR was 47.3 ± 36.2 ml and the average PVR at the last visit was 26.0 ± 7.0 ml. These 4 patients received antimicrobial agents, including levofloxacin 100 mg thrice during 7days in 3 and cefcapene pivoxil 100 mg thrice during 7days in 1, irrespective of no specific UTI symptoms. Although those antimicrobial agents had favorable susceptibility to isolated pathogens, including E. faecalis in 2, E. coli and S. epidermidis, LUTS in these 4 patients remained unchanged. In 1 patient with continuous pyuria, the initial PVR was 17 ml and that at the last visit was 57 ml. During follow-up, 12 of the 16 patients were treated only with an alpha-blocker. In these 12 patients, pyuria disappeared in 5 and continued in 7. In the former 5 patients, the average initial PVR was 95.4 ± 62 and the average PVR at the last visit was 92.8 ± 66.2 ml. In the latter 7 patients, the average initial PVR was 143.1 ± 139.4 ml and the average PVR at the last visit was 55.0 ± 51.1 ml. 4. Discussion In Japan, urologists generally conduct urinalysis at each routine examination when they follow-up patients with LUTS. When we recognize pyuria in routine urinalysis, we inquire about symptoms such as urethral or micturitional pain, and do urinary culture to determine the presence of bacterial strains if necessary. Therefore, pyuria with or without bacteriuria is one of the objective diagnostic data for symptomatic UTI and asymptomatic bacteriuria or pyuria in Japan. In a previous Japanese study [6], 65 (4.2%) of 1542 patients with LUTS/BPH presented with bacteriuria in spite of there being no previous urinary tract manipulation. Unfortunately, the condition of PVR was not clearly shown in that study; however, the frequency of pyuria with or without bacteriuria was similar to the results of our study that showed 4.9% of patients with LUTS at the first visit. Therefore, we confirmed that not negligible number of patients with LUTS as well as those with LUTS/BPH had pyuria or bacteriuria without any previous urinary tract manipulation. In our study, the isolated bacterial strains were not uniform and showed no definite trend. This study did not reveal specific bacterial characteristics; however, urine culture should be done for patients with significant
S. Takahashi et al. / J Infect Chemother 21 (2015) 31e33
PVR because it can identify causative pathogens. After isolation of the pathogens, the results of antimicrobial susceptibility tests make it possible to carry out antimicrobial prophylaxis efficiently before urological operation or manipulation. The association between significant PVR and UTI remains controversial. Most reports have defined UTI as both symptomatic UTI and asymptomatic bacteriuria. In general, UTI means urinary tract infection with specific urinary tract symptoms related to the infection. Studies in Brazil and Germany [1,2] showed a positive correlation between significant PVR and UTI, whereas other studies in the United Kingdom and Norway [3,4] reported that there was no relation between them. A unique experimental study [5] showed that significant PVR led to a urinary bacterial count higher than in normal residual urine. The results of our study showed that larger PVR volume was related to a higher frequency of pyuria with or without bacteriuria, although we could not determine the cutoff value of PVR to predict the risk of developing UTI. If a larger PVR volume is related to the occurrence of UTI, medical treatment for LUTS/BPH, which might decrease the PVR, could lead to a decrease in the frequency of pyuria with or without bacteriuria. The results in our study revealed that more than half of the patients with pyuria at the first visit continued to exhibit the same urinary findings. However, none of the patients having pyuria with or without bacteriuria at the first visit advanced to febrile UTI. These results are important for patients whose initial complaint is LUTS. To date, when asymptomatic bacteriuria (ASB) is observed in patients, antimicrobial prophylaxis has only been indicated for pregnant women and patients for whom a urological operation or urological manipulation is planned. Basically, ASB is defined as the existence of a significant number of bacteria in urine. The definition is different between ASB and pyuria with or without bacteriuria in this study; however, the potential presence of urinary bacteria or inflammation is extremely common. Therefore, we have to discuss whether LUTS/BPH patients with asymptomatic pyuria or ASB should be treated with antimicrobial agents. In our study, there was no clear relationship between persisting pyuria and a change in PVR in patients treated with an alpha-blocker with or without antimicrobial agents. However, even if the patients with LUTS had pyuria at the first visit, it rarely led to febrile UTI without any urological manipulation.
33
There were several limitations in this study. The relatively small number of patients led to a small number of patients with pyuria. In the patients with pyuria, urine culture could not necessarily be examined due to the study's retrospective nature. Nor was PVR measurement always done regularly. Indeed, PVR tends to always change in various circumstances. However, there have been few studies attempting to clarify the association between LUTS and pyuria to date and the findings of this study should be useful for urologists in the clinical setting. In conclusion, the frequency of pyuria with or without bacteriuria at the first visit was 4.9% for male patients without any previous urological manipulation whose chief complaint was LUTS. No patient developed febrile UTI during his clinical course. Antimicrobial chemotherapy should be done if the patients with LUTS have symptomatic UTI or undergo any urological manipulations. However, for asymptomatic patients simply having pyuria with or without bacteriuria, antimicrobial chemotherapy may not be indicated.
Conflict of interest No conflict of interest.
References [1] Truzzi JC, Almeida FM, Nunes EC, Sadi MV. Residual urinary volume and urinary tract infectionewhen are they linked? J Urol 2008;180:182e5. [2] May M, Brookman-Amissah S, Hoschke B, Gilfrich C, Braun KP, Kendel F. Postvoid residual urine as a predictor of urinary tract infectioneis there a cutoff value in asymptomatic men? J Urol 2009;181:2540e4. [3] Hampson SJ, Noble JG, Rickards D, Milroy EJ. Does residual urine predispose to urinary tract infection? Br J Urol 1992;70:506e8. [4] Omli R, Skotnes LH, Mykletun A, Bakke AM, Kuhry E. Residual urine as a risk factor for lower urinary tract infection: a 1-year follow-up study in nursing homes. J Am Geriatr Soc 2008;56:871e4. [5] Hinman Jr F, Cox CE. The voiding vesical defense mechanism: the mathematical effect of residual urine, voiding interval and volume on bacteriuria. J Urol 1966;96:491e8. [6] Fujita K, Murayama K, Ida T, Sumiyoshi Y, Yoshida K, Takaha M, et al. A cooperative study on the incidence of bacteriuria in patients with benign prostatic hypertrophy. Jpn J Urol 1994;85:1348e52.
Contents lists available at ScienceDirect
Journal of Infection and Chemotherapy journal homepage: http://www.elsevier.com/locate/jic
Original article
Do patients who complain of lower urinary tract symptoms frequently have clinically significant pyuria? Satoshi Takahashi*, Koji Ichihara, Yoshiki Hiyama, Teruhisa Uehara, Jiro Hashimoto, Naoya Masumori Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo 060-8543, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 16 June 2014 Received in revised form 26 July 2014 Accepted 22 August 2014 Available online 12 September 2014
There is still controversy about whether post-void residual (PVR) urine volume affects the onset of urinary tract infection (UTI). In addition, although male patients with lower urinary tract symptoms (LUTS) might potentially have PVR, the association between LUTS and UTI or asymptomatic pyuria with or without bacteriuria remains unclear. We studied the frequency of asymptomatic pyuria, with and without bacteriuria, in patients with LUTS without a previous history of urinary tract manipulation at the first visit and their sequential courses. This retrospective study was done by reviewing medical charts. A total of 453 male patients who complained of LUTS and visited our outpatient clinic in 2008 were included in this study. The frequency of pyuria, with or without bacteriuria, in this study at the first visit was 4.9%. The median PVR volumes at the initial examination were 79 ml in the 22 patients with pyuria and 22 ml in the 431 patients without pyuria. The difference of the PVR volume between the patients with pyuria and those without pyuria was statistically significant (p ¼ 0.0095). Twelve patients were treated with alpha-blockers without antimicrobial chemotherapy and pyuria disappeared in 5 (41.7%) of them. However, the decrease in the rate of PVR was not significantly different between the patients with persisting pyuria and those without pyuria. A not negligible number of patients with LUTS had pyuria at the first visit; however, there was no febrile UTI in their clinical course even if they received no urological manipulation. © 2014, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
Keywords: Urinary tract infection Pyuria Post-void residual Lower urinary tract symptoms
1. Introduction Several studies [1,2] showed positive correlations between significant post-void residual (PVR) urine volume and urinary tract infection (UTI), whereas other studies [3,4] reported that there was no relation between them. In an experimental study [5], significant PVR led to the urinary bacterial count being higher than in normal residual urine. In the clinical situation, the question of whether PVR affects the onset of UTI remains controversial. A study on patients with benign prostatic hyperplasia (BPH) [6] showed that manipulation of the urinary tract during follow-up was likely to lead to UTI in patients with considerable PVR. Some patients with lower urinary tract symptoms (LUTS) fail to completely void urine and this can lead to some degree of PVR. * Corresponding author. Department of Urology, Sapporo Medical University School of Medicine, S1, W16, Chuo-ku, Sapporo 060-8543, Japan. Tel.: þ81 11 611 2111x3472; fax: þ81 11 612 2709. E-mail addresses: [email protected], [email protected] (S. Takahashi).
When patients with LUTS have considerable PVR at the first visit to a urologic clinic, the association between LUTS with/without considerable PVR and UTI is unclear. However, if patients with asymptomatic bacteriuria undergo urinary tract manipulation without any antimicrobial prophylaxis, febrile UTI can develop. Therefore, we studied the frequency of pyuria and the clinical courses of male patients with LUTS without a previous history of urinary tract manipulation. Especially, we focused the clinical course in the patients with pyuria at the first visit. 2. Material and methods This retrospective study was done by reviewing medical charts. The male patients who complained of LUTS and first visited the outpatient clinic in Sapporo Medical University Hospital from January through December 2008 were included in this study. The patients who underwent urethral manipulation within the previous 1 month, e.g., urethral catheterization or cystoscopic examination, or were clinically diagnosed as having male urethritis or
http://dx.doi.org/10.1016/j.jiac.2014.08.022 1341-321X/© 2014, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
32
S. Takahashi et al. / J Infect Chemother 21 (2015) 31e33
prostate cancer, and those treated with antimicrobial agents within 1 month, with a previous history of urinary retention, or who underwent transurethral prostatic surgery, and those whose PVR was not determined at the initial visit were excluded from this study. As a strict definition of male urethritis, urethral or micturitional pain was necessary for diagnosis. The patients who complained of such pain and received antimicrobial agents at the first visit were also excluded from this study. At the first visit, a basic examination including an interview, abdominal and digital rectal examinations, urinalysis, uroflowmetry and measurement of PVR was performed. When the patients continued to visit the clinic thereafter, the data from the examination at each visit were evaluated if possible. The intervals between visits were sometimes irregular due to the retrospective nature of the study. The follow-up period was defined as that from the day of the first visit to that of the last visit noted in the medical chart. Throughout the clinical course, certified urologists checked the data and made diagnoses. PVR was determined as the maximum volume determined by transabdominal ultrasound using a BladderScan BVI3000 (Sysmex Co. Kobe, Japan) postvoiding. Urinalysis was done using midstream urine and pyuria in this study was defined as 5 or more white blood cells (WBC) per high power field (hpf) microscopically with or without bacteriuria. Bacteriuria was defined as an isolated bacterial count of 105 colonyforming units (CFU)/ml or more. Statistical analysis was done using the ManneWhitney test, chisquare test and KruskaleWallis test for the relation between PVR and UTI. The median volume of PVR is presented as the volume and its range. The average volume is presented as the volume and its standard deviation. The details of this research project were approved the Review Board in Sapporo Medical University Hospital (http://web.sapmed.ac.jp/byoin/chiken/irb.html) (No. 25-115). This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) (http://www. umin.ac.jp/ctr/index.htm) (UMIN ID: UMIN000011632). 3. Results Altogether, 453 patients were included in this study. Their median age was 69 (36e93) years. The median volume of PVR was 25 (0e500) ml. Twenty-two (4.9%) of the 453 had pyuria. Urine culture was done for 10 of these 22 patients and bacterial strains were isolated from 7 of them. The isolated bacterial strains were Enterococcus faecalis in 2, Staphylococcus haemolyticus in 2, Escherichia coli in 1, Staphylococcus epidermidis in 1, and Corynebacterium striatum in 1. In 12 patients without applying urine culture, the microscopic findings showed positive bacteriuria in 5 patients and negative bacteriuria in 7 patients. Therefore, there were 12 (54.5%) of these 22 patients with any degree of bacteriuria. The median PVR volumes at the initial examination were 79 ml in the 22 patients with pyuria and 22 ml in the 431 patients without Table 1 Patients' characteristics between those with pyuria and those without pyuria. Factors
Patients with pyuria
Patients without pyuria
Number Median age (range) Median PVR (ml) (range) Diagnosis BPH Neurogenic bladder Others
22 71 (58e88) 79 (0e438)
431 69 (36e93) 22 (0e500)
19 (86.3%) 2 (9.1%) 1 (4.5%)
354 (82.1%) 53 (12.3%) 24 (5.6%)
PVR; post-void residual. BPH; benign prostatic hypertrophy. a ManneWhitney test. b Chi-square test.
p Value
0.2054a 0.0095a 0.8692b
Table 2 The association between the 3 groups of PVR volume and the frequency of pyuria. PVR volume (ml)
Number of patients with pyuria
Number of patients without pyuria
PVR < 50 50 & PVR < 100 100 & PVR
8 (2.8%) 6 (8.2%) 8 (8.3%)
276 (97.2%) 67 (91.8%) 88 (91.7)
pyuria. The difference in the PVR volume between the patients with and without pyuria was statistically significant (p ¼ 0.0095) (Table 1). When the PVR volume was divided into 3 groups (less than 50 ml, 50e100 ml, and more than 100 ml), the frequency of pyuria was higher in the groups with PVR of 50 ml or more than that in the group with PVR of less than 50 ml (p ¼ 0.0100) (Table 2). We then tried to clarify the cutoff value to predict UTI but we could not determine it. However, if PVR of 180 ml [1] was used as the cutoff value, the sensitivity was 8.6% and specificity was 95.5%. For the 22 patients with pyuria at the first visit, the average follow-up period was 13.5 (±13.3) months. During the follow-up period, no febrile UTI event occurred. Of these patients, 16 with LUTS/BPH received alpha 1 adrenergic receptor blockade (alphablocker treatment) and were analyzed during the follow-up period after the first visit. During follow-up, 4 of these16 patients were treated with antimicrobial agents and pyuria had disappeared in 3 of the 4 at the last visit. In these 3 patients, the average initial PVR was 47.3 ± 36.2 ml and the average PVR at the last visit was 26.0 ± 7.0 ml. These 4 patients received antimicrobial agents, including levofloxacin 100 mg thrice during 7days in 3 and cefcapene pivoxil 100 mg thrice during 7days in 1, irrespective of no specific UTI symptoms. Although those antimicrobial agents had favorable susceptibility to isolated pathogens, including E. faecalis in 2, E. coli and S. epidermidis, LUTS in these 4 patients remained unchanged. In 1 patient with continuous pyuria, the initial PVR was 17 ml and that at the last visit was 57 ml. During follow-up, 12 of the 16 patients were treated only with an alpha-blocker. In these 12 patients, pyuria disappeared in 5 and continued in 7. In the former 5 patients, the average initial PVR was 95.4 ± 62 and the average PVR at the last visit was 92.8 ± 66.2 ml. In the latter 7 patients, the average initial PVR was 143.1 ± 139.4 ml and the average PVR at the last visit was 55.0 ± 51.1 ml. 4. Discussion In Japan, urologists generally conduct urinalysis at each routine examination when they follow-up patients with LUTS. When we recognize pyuria in routine urinalysis, we inquire about symptoms such as urethral or micturitional pain, and do urinary culture to determine the presence of bacterial strains if necessary. Therefore, pyuria with or without bacteriuria is one of the objective diagnostic data for symptomatic UTI and asymptomatic bacteriuria or pyuria in Japan. In a previous Japanese study [6], 65 (4.2%) of 1542 patients with LUTS/BPH presented with bacteriuria in spite of there being no previous urinary tract manipulation. Unfortunately, the condition of PVR was not clearly shown in that study; however, the frequency of pyuria with or without bacteriuria was similar to the results of our study that showed 4.9% of patients with LUTS at the first visit. Therefore, we confirmed that not negligible number of patients with LUTS as well as those with LUTS/BPH had pyuria or bacteriuria without any previous urinary tract manipulation. In our study, the isolated bacterial strains were not uniform and showed no definite trend. This study did not reveal specific bacterial characteristics; however, urine culture should be done for patients with significant
S. Takahashi et al. / J Infect Chemother 21 (2015) 31e33
PVR because it can identify causative pathogens. After isolation of the pathogens, the results of antimicrobial susceptibility tests make it possible to carry out antimicrobial prophylaxis efficiently before urological operation or manipulation. The association between significant PVR and UTI remains controversial. Most reports have defined UTI as both symptomatic UTI and asymptomatic bacteriuria. In general, UTI means urinary tract infection with specific urinary tract symptoms related to the infection. Studies in Brazil and Germany [1,2] showed a positive correlation between significant PVR and UTI, whereas other studies in the United Kingdom and Norway [3,4] reported that there was no relation between them. A unique experimental study [5] showed that significant PVR led to a urinary bacterial count higher than in normal residual urine. The results of our study showed that larger PVR volume was related to a higher frequency of pyuria with or without bacteriuria, although we could not determine the cutoff value of PVR to predict the risk of developing UTI. If a larger PVR volume is related to the occurrence of UTI, medical treatment for LUTS/BPH, which might decrease the PVR, could lead to a decrease in the frequency of pyuria with or without bacteriuria. The results in our study revealed that more than half of the patients with pyuria at the first visit continued to exhibit the same urinary findings. However, none of the patients having pyuria with or without bacteriuria at the first visit advanced to febrile UTI. These results are important for patients whose initial complaint is LUTS. To date, when asymptomatic bacteriuria (ASB) is observed in patients, antimicrobial prophylaxis has only been indicated for pregnant women and patients for whom a urological operation or urological manipulation is planned. Basically, ASB is defined as the existence of a significant number of bacteria in urine. The definition is different between ASB and pyuria with or without bacteriuria in this study; however, the potential presence of urinary bacteria or inflammation is extremely common. Therefore, we have to discuss whether LUTS/BPH patients with asymptomatic pyuria or ASB should be treated with antimicrobial agents. In our study, there was no clear relationship between persisting pyuria and a change in PVR in patients treated with an alpha-blocker with or without antimicrobial agents. However, even if the patients with LUTS had pyuria at the first visit, it rarely led to febrile UTI without any urological manipulation.
33
There were several limitations in this study. The relatively small number of patients led to a small number of patients with pyuria. In the patients with pyuria, urine culture could not necessarily be examined due to the study's retrospective nature. Nor was PVR measurement always done regularly. Indeed, PVR tends to always change in various circumstances. However, there have been few studies attempting to clarify the association between LUTS and pyuria to date and the findings of this study should be useful for urologists in the clinical setting. In conclusion, the frequency of pyuria with or without bacteriuria at the first visit was 4.9% for male patients without any previous urological manipulation whose chief complaint was LUTS. No patient developed febrile UTI during his clinical course. Antimicrobial chemotherapy should be done if the patients with LUTS have symptomatic UTI or undergo any urological manipulations. However, for asymptomatic patients simply having pyuria with or without bacteriuria, antimicrobial chemotherapy may not be indicated.
Conflict of interest No conflict of interest.
References [1] Truzzi JC, Almeida FM, Nunes EC, Sadi MV. Residual urinary volume and urinary tract infectionewhen are they linked? J Urol 2008;180:182e5. [2] May M, Brookman-Amissah S, Hoschke B, Gilfrich C, Braun KP, Kendel F. Postvoid residual urine as a predictor of urinary tract infectioneis there a cutoff value in asymptomatic men? J Urol 2009;181:2540e4. [3] Hampson SJ, Noble JG, Rickards D, Milroy EJ. Does residual urine predispose to urinary tract infection? Br J Urol 1992;70:506e8. [4] Omli R, Skotnes LH, Mykletun A, Bakke AM, Kuhry E. Residual urine as a risk factor for lower urinary tract infection: a 1-year follow-up study in nursing homes. J Am Geriatr Soc 2008;56:871e4. [5] Hinman Jr F, Cox CE. The voiding vesical defense mechanism: the mathematical effect of residual urine, voiding interval and volume on bacteriuria. J Urol 1966;96:491e8. [6] Fujita K, Murayama K, Ida T, Sumiyoshi Y, Yoshida K, Takaha M, et al. A cooperative study on the incidence of bacteriuria in patients with benign prostatic hypertrophy. Jpn J Urol 1994;85:1348e52.
