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Updated: May 23, 2026
An In Vitro Bladder Model of Catheter-Associated Urinary Tract Infection
Published on: June 24, 2025
Extensive characterizations of bacteria isolated from catheterized urine and stone matrices in patients with
Ratree Tavichakorntrakool1, Vitoon Prasongwattana, Seksit Sungkeeree
1Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Science, Khon Kaen University, Khon Kaen, Thailand.
Background:
Urinary tract infections are generally known to be associated with nephrolithiasis, particularly struvite stone, in which the most common microbe found is urea-splitting bacterium, i.e. Proteus mirabilis. However, our observation indicated that it might not be the case of stone formers in Thailand. We therefore extensively characterized microorganisms associated with all types of kidney stones.
Methods:
A total of 100 kidney stone formers (59 males and 41 females) admitted for elective percutaneous nephrolithotomy were recruited and microorganisms isolated from catheterized urine and cortex and nidus of their stones were analyzed.
Results:
From 100 stone formers recruited, 36 cases had a total of 45 bacterial isolates cultivated from their catheterized urine and/or stone matrices. Among these 36 cases, chemical analysis by Fourier-transformed infrared spectroscopy revealed that 8 had the previously classified 'infection-induced stones', whereas the other 28 cases had the previously classified 'metabolic stones'. Calcium oxalate (in either pure or mixed form) was the most common and found in 64 and 75% of the stone formers with and without bacterial isolates, respectively. Escherichia coli was the most common bacterium (approximately one-third of all bacterial isolates) found in urine and stone matrices (both nidus and periphery). Linear regression analysis showed significant correlation (r = 0.860, P < 0.001) between bacterial types in urine and stone matrices. Multidrug resistance was frequently found in these isolated bacteria. Moreover, urea test revealed that only 31% were urea-splitting bacteria, whereas the majority (69%) had negative urea test.
Conclusions:
Our data indicate that microorganisms are associated with almost all chemical types of kidney stones and urea-splitting bacteria are not the major causative microorganisms found in urine and stone matrices of the stone formers in Thailand. These data may lead to rethinking and a new roadmap for future research regarding the role of microorganisms in kidney stone formation.
Insights
Microorganisms are linked to most kidney stones in Thailand, but urea-splitting bacteria are not the primary cause. This finding challenges previous assumptions about infection-induced stones and suggests new research directions.
Area of Science:
- Microbiology
- Urology
- Nephrology
Background:
- Urinary tract infections are commonly linked to kidney stones, especially struvite stones, often caused by urea-splitting bacteria like Proteus mirabilis.
- However, this association may not hold true for stone formers in Thailand, prompting further investigation into local microbial patterns.
Purpose of the Study:
- To extensively characterize the microorganisms associated with all types of kidney stones in Thai patients.
- To determine the prevalence and types of bacteria present in urine and kidney stone matrices.
Main Methods:
- 100 kidney stone formers undergoing percutaneous nephrolithotomy were recruited.
- Microorganisms were isolated from catheterized urine, stone cortex, and nidus.
- Chemical analysis of stones was performed using Fourier-transformed infrared spectroscopy.
Main Results:
- 36 out of 100 patients had bacterial isolates from urine and/or stone matrices.
- Calcium oxalate was the most common stone type (64-75%).
- Escherichia coli was the most frequent isolate; only 31% of isolates were urea-splitting bacteria, contrary to expectations.
Conclusions:
- Microorganisms are associated with nearly all chemical types of kidney stones in Thailand.
- Urea-splitting bacteria are not the predominant causative agents in this population.
- These findings necessitate a re-evaluation of the role of microorganisms in kidney stone formation and suggest new research avenues.
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