Abstract
Background:
Many Chinese herbal formulations are used in the treatment of urinary tract infection. Clinical isolates of Escherichia coli (E. coli) resistant to Chinese herbs have been identified rarely. Report here is a case in which Chinese herbs–resistant E. coli isolate was identified.
Case:
The strain of E. coli C16 was isolated from urine of a 72-year-old woman with a diagnosis of pyelonephritis. Standard disc diffusion methodology was used to test the Chinese herbal decoction against E. coli C16. The minimum inhibitory concentration value was 0.1 g/mL. The minimum bactericidal concentration value was 0.2 g/mL. The decoction was orally administered for 4 weeks.
Results:
The therapeutic regimen was well tolerated initially. At the end of 4 weeks, the disease relapsed. E. coli C16 was isolated again, which was resistant to herbal solution.
Conclusions:
This case illustrates that excessive exposure to Chinese herbs used in unchanging standard formulations can also lead to bacterial resistance. Appropriate clinical use of Chinese herbs is imperative.
Introduction
Herbal medicine has been an integral part of Traditional Chinese Medicine for more than 2000 years. Many herbal formulations have been developed and are used in the treatment of urinary tract infection (UTI). Some Chinese herbs are known to have antimicrobial effects, such as Scutellaria baicalensis and Coptis chinensis.
Clinical isolates of Escherichia coli (E. coli) resistant to Chinese herbs have been identified rarely. A case is reported here in which a Chinese herbs–resistant E. coli isolate was identified in March 2011.
Case Report
The strain was isolated from a 72-year-old woman in our previous research. 1 She had a past medical history of a right breast mass that required a resection and radiation therapy. She presented to our clinic with dysuria, frequency, suprapubic pain, urinary incontinence, and a white blood cell (WBC) count of 10,050 and was admitted with a diagnosis of pyelonephritis. Urinalysis revealed positive leukocyte esterase with 30–35 WBCs per high-power field. Urine cultures yielded 50,000 colonies of E. coli. The isolation and identification of E. coli C16 was according to methods recommended by Olsson et al. 2
The patient was started on a Chinese herbal decoction as follow: Tong Cao (Medulla tetrapanacis) 20 g, Hua Shi (talcum) 15 g, Chi Shao (Radix Paeoniae rubrae) 15 g, Xiao Hui Xiang (Fructus Foeniculi vulgaris) 15 g, Rou Gui (Cortex Cinnamomi) 15 g, Li Zhi He (Semen litchi) 15 g, Tian Kui Zi (Radix Semiaquilegiae) 15 g, Zi Hua Di ding (Herba cum Rd Violae yedoensitis) 20 g, Qu Mai (Herba Dianthi) 15 g, Ma Chi Xian (Herba Portulacae) 50 g, and Pu Gong Ying (Herba taraxaci) 30 g. The decoction was prepared by mixing the crude herbs in 800 mL water, obtaining 200 mL of liquor after the herbs were decocted in 800 mL of water (100°C for 30 minutes twice). The decoction was orally administered as 200 mL/day for 2 weeks.
Standard disc diffusion methodology 3 was used to test the decoction against E. coli C16. The minimal inhibitory concentration value of herbal solution for E. coli C16 was 0.1 g/mL. The minimum bactericidal concentration (MBC) value was 0.2 g/mL. 1
The therapeutic regimen was well tolerated initially. The aforementioned symptoms subsided after 2 weeks of treatment. Urinalysis showed 3–5 WBCs per high-power field. The patient continued the oral administration. At the end of the other 2 weeks, the disease relapsed. E. coli C16 was isolated again, which was resistant to herbal solution.
Discussion
Antibiotic-resistant bacteria are a major health concern. This problem is exacerbated by not only the bacteria showing a wide resistance to most of the current antibiotics but also other antimicrobial products such as disinfectants and antiseptics. 4 The literature review shows that this is the first report of E. coli resistant to Chinese herbs.
The occurrence of bacterial resistance has been largely attributed to the overuse of antibiotics and the continual exposure of the bacteria to low levels of antibiotics. 5 Review of this patient's medical history revealed no other identifiable risk factors, other than the indiscriminate use of a standard Chinese formula, for the isolation of Chinese herb–resistant E. coli C16. This case illustrates that excessive exposure to Chinese herbs used in standard formulations can also lead to bacterial resistance.
The convenience of use of Chinese herbs is well recognized. However, increased prescription of standard Chinese formulations for common infections such as UTIs will facilitate the emergence of resistance and promote the emergence of Chinese herb–resistant strains and, therefore, should be discouraged as it will undermine the efficacy of Chinese herbs to treat other infections. Close attention is required to monitor Chinese herbs susceptibility patterns and the resistance in isolates of other bacteria causing UTIs and other infections.
Conclusions
Chinese herbal medicine treats patients on an individual basis in which the prescription will vary depending on each case's presentation (e.g., the tongue, the pulse, individual symptoms and signs). Moreover, as treatment progresses, the prescribing doctor changes the formulation to fit the changing pattern. Practiced in this way, Chinese herbal medicine is unlikely to facilitate the emergence of herb-resistant strains because there is no standard formulation for a specific disease (e.g., UTI). On the other hand, the indiscriminate use of standard formulations may predispose to herb-resistant strains. This case indicates that appropriate clinical use of Chinese herbs is imperative as they become more widely prescribed.
Footnotes
Acknowledgment
The research was funded by the Jilin Provincial Science & Technology Department. We thank Hewei Wei, MD for helpful assistance in preparing the manuscript.
Disclosure Statement
The authors state that no dual competing interests, or competing loyalties exist.