Low Concentration of Wenyang Tonglin Decoction Promotes Conjugation and Transfer of Drug-Resistant Plasmids among Heterologous Strains.

OBJECTIVE: To investigate the effect of low concentration of Wenyang Tonglin Decoction (WTD) on the binding conditions of R45 plasmid conjugative transfer under liquid phase conjugation and its mechanism. METHODS: Escherichia coli CP9 (R45) and Staphylococcus aureus RN450RF were cultured in medium containing WTD, and their minimum inhibitory concentration (MIC) values were obtained. Using promoter fusion technology, E. coli CP9 (R45) containing a promoter fusion was obtained. ß-Galactosidase activity of TrfAp and TrbBp was tested, and the mRNA expression of regulatory factors (TrbA, KorA, and KorB) was detected by real-time fluorescent quantitative polymerase chain reaction. RESULTS: The MIC of E. coli CP9 (R45) was 400 g/L and that of S. aureus RN450RF was 200 g/L. When the drug concentration in the culture medium was 200 g/L, the highest number of conjugants was (3.47 ±0.20) × 107 CFU/mL At 90 h of conjugation, the maximum number of conjugants was (1.15 ±0.06) × 108 CFU/mL When the initial bacterial concentration was 108 CFU/mL, the maximum number of conjugants was (3.47 ± 0.20) × 107 CFU/mL. When the drug concentration was 200 g/L, the ß-galactosidase activity of TrfAp and TrbBp significantly increased; the relative quantification of TrbA, KorA and KorB were significantly inhibited. CONCLUSION: Low concentration of WTD promoted the development of bacterial resistance by affecting promoters and inhibiting the expression of regulatory factors.

Changes of QT Dispersion in Hemodialysis Patients after Administrating Zhigancao Decoction ().

OBJECTIVE: To observe the alteration of QT dispersion (QTd) and QTc dispersion (QTcd) in hemodialysis patients after oral administration of Zhigancao Decoction (, Roasted Licorice Decoction, RLD). METHODS: To investigate the alteration of QTd and QTcd in 68 routine hemodialysis patients before and after hemodialysis with 12-lead electrocardiogram (ECG) after orally administrated RLD for 4 weeks. Blood was also taken for measurement of plasma electrolytes, liver function, renal function, hemoglobin (Hgb) and hematocrit (HCT). RESULTS: After hemodialysis, QTd and QTcd were prolonged evidently; the difference was significant between before and after hemodialysis (P<0.05). After RLD orally administrated for 4 weeks, QTd and QTcd only slightly increased after dialysis compared with pre-dialysis (P>0.05). The QTd and QTcd of the post-therapy-post-dialysis decreased significantly compared with the pre-therapy-post-dialysis (P<0.05). There were no other significant changes in other variables (post-therapy-pre-dialysis vs. pre-therapy-pre-dialysis, or post-therapy-post-dialysis vs. pre-therapy-post-dialysis;P>0.05). After therapy, the number of patients with supraventricular arrhythmia, occasional ventricular premature beat and multiple ventricular premature beat were decreased from 15 to 4, 10 to 2 and 7 to 1, respectively. CONCLUSION: RLD therapy not only lowered the increased QTd and QTcd after hemodialysis, but also displayed a safety profile.

Prophylactic herbal therapy prevents experimental ascending urinary tract infection in mice.

OBJECTIVE: To study the preventive effect of herbal formulation on experimental murine urinary tract infection (UTI) induced by Dr Escherichia coli 11128. METHODS: E. coli 11128 carrying Dr fimbriae was isolated from patients with chronic pyelonephritis. The minimal inhibitory concentration (MIC) value of herbal solution for E. coli 11128 was determined for further studies. Forty C3H/HeJ mice were divided into the herb-treated group (n=20, given Chinese herbs by gavage at an average dose of 20 g/kg body weight daily 3 days before inoculation), and control group (n=20, given the same amount of distilled water by gavage). Three and 6 days after infection, bacteria were counted in the urine and the kidneys of the mice. Kidney histopathologic changes were evaluated. Neutrophils infiltration and accumulation were detected. RESULTS: The MIC value of herbal solution was 0.1 g/mL for the E. coli 11128. In herb-treated mice, there was a significant reduction in bacterial counts in urine and colonization densities of kidneys. Microscopic studies revealed signs of inflammation in kidneys. In herb-treated mice, herbal administration resulted in significantly reduced neutrophilic infiltrates (P<0.05). The semi-quantitative scores for renal lesions were significantly lower (P<0.05). CONCLUSION: Prophylactic administration of herbal formulation potentiated the effect in partially preventing experimental murine ascending UTI.

Transfer of Herb-Resistance Plasmid From Escherichia coli to Staphylococcus aureus Residing in the Human Urinary Tract.

BACKGROUND: Plasmid transfer among bacteria provides a means for dissemination of resistance. Plasmid Analysis has made it possible to track plasmids that induce resistance in bacterial population. OBJECTIVES: To screen the presence of herb-resistance plasmid in Escherichia coli strains and determine the transferability of this resistance plasmid directly from E. coli to the Gram-positive, Staphylococcus aureus. MATERIALS AND METHODS: The donor strain E. coli CP9 and recipient strain S. aureus RN450RF were isolated from UTI patients. E. coli CP9 was highly resistant to herbal concoction. Isolates of S. aureus RN450RF were fully susceptible. Total plasmid DNA was prepared and transferred into E. coli DH5α. Transconjugants were selected on agar plates containing serial dilutions of herbal concoction. Resistance plasmid was transferred to susceptible S. aureus RN450RFin triple replicas. The mating experiments were repeated twice. RESULTS: The identified 45 kb herb-resistance plasmid could be transferred from E. coli CP9 isolates to E. coli DH5α. As a consequence E. coli DH5α transconjugant MIC increased from 0.0125 g/mL to 0.25 g/mL. The plasmid was easily transferred from E. coli CP9 strain to S. aureus RN450RF with a mean transfer rate of 1×10(-2) transconjugants/recipient. The E. coli donor and the S. aureus RN450RF transconjugant contained a plasmid of the same size, which was absent in the recipient before mating. Susceptibility testing showed that the S. aureus RN450RF transconjugant was resistant to herbal concoction. CONCLUSIONS: E. coli herb-resistance plasmid can replicate and be expressed in S. aureus.

Pyelonephritis Caused Solely by Escherichia hermanii.

INTRODUCTION: In contrast with Escherichia coli, the association of E. hermanii with urinary tract infections has not been described. CASE PRESENTATION: In this case, E. hermanii was the sole isolate recovered from urine specimens of a pyelonephritis patient. The organism was found to be susceptible to piperacillin-tazobactam, ceftazidime, cefazolin, cefixime, aztreonam, gentamicin, tobramycin, imipenem, meropenem and amikacin, and resistant to amoxicillin. Antibiotic treatment was initiated with oral cefixime (400 mg every 24 hours). The symptoms were relieved within 72 hours after therapy. A urine sample was taken seven days after antibiotic therapy. E. hermanii was no longer isolated. DISCUSSION: The present case demonstrates that the uropathogenic E. hermanii clone can cause destruction of the kidneys. During asymptomatic bacteriuria or cystitis, the bacteria remain in the urinary tract. Even when pyelonephritis develops, inflammatory response of the host is still restricted to the urinary tract. These signs mean that uropathogenic E. hermanii may be not very virulent.

Alteration of heart rate variability parameters in nondiabetic hemodialysis patients.

OBJECTIVE: We attempt to identify heart rate variability (HRV) components and decide whether or not such components are more sensitive to the hemodialysis (HD) process by excluding the presence of comorbid conditions known to affect HRV. METHODS: It was a prospective cohort study of factors associated with HRV. Thirty-five HD patients were admitted to the study. The research was divided into three phases. During the first phase, baseline Holter and blood pressure recordings were carried out. Then in the second phase, the patients were admitted for HD with continuous Holter and blood pressure recording. The third phase was after HD with continuous Holter and blood pressure recording. The frequency and time domain analyses of HRV were carried out by an independent, blinded investigator. Plasma Na+, K+, ionized Ca, hemoglobin, serum creatinine and blood urea nitrogen (BUN) were checked 1 h before and 2 h after HD. RESULTS: After HD, the serum creatinine and BUN were obviously reduced (p < 0.01), which was also expressed by fractional urea clearance (K(t)/V; 1.55 +/- 0.25), which means efficient HD. Standard deviation of all RR intervals and low-frequency/high-frequency (LF/HF) ratio were reduced significantly (p < 0.05) at the 'HD for 3 h' time point while the blood pressure levels were relatively stable during the HD process. The ultrafiltration rate and K(t)/V appeared to be the main determinants of the LF/HF ratio in HD. In our cases, the LF/HF ratio positively correlated with K(t)/V and negatively correlated with ultrafiltration volume. CONCLUSION: Our study suggested a shift in sympathovagal balance toward sympathetic activation during the HD process. Sympathetic overactivity is positively correlated with the ultrafiltration rate, and negatively correlated with the K(t)/V which means that the HD process itself affects HRV parameters indeed.