Therapeutic Drug Monitoring of Ceftazidime-Avibactam Concentrations in Carbapenem-Resistant K. pneumoniae-Infected Patients With Different Kidney Statuses

Aims: Carbapenem-resistant K. pneumoniae (CRKP) is the most common carbapenem-resistant Enterobacteriaceae with high mortality. Ceftazidime-avibactam (CAZ-AVI) has exhibited excellent in vitro activity in vivo against CRKP. However, the efficacy of CAZ-AVI in KPC-producing CRKP-infected patients with different kidney statuses varies, such as renal insufficiency, normal renal function, and augmented renal clearance (ARC). We explored the use of therapeutic drug monitoring (TDM) to evaluate the concentration and efficacy of CAZ-AVI in CRKP-infected patients with different kidney statuses.

Methods: Serum concentrations for CAZ and AVI were determined by the high-performance liquid chromatography method. Bacterial identification, routine susceptibility testing, renal function index, and others were performed in standard protocols in the hospital’s clinical laboratories.

Results: In the two patients with ARC, in case 1, CAZ-AVI 2.5g q6h was used with good efficacy, and the concentrations were up to the pharmacokinetics/pharmacodynamics targets. In Case 2, 2.5 g q8h was used with invalid effectiveness, and AVI C_min was only 0.797 mg/l, which is lower than the PK/PD target. Case 3 was renal insufficiency using CAZ-AVI 1.25 q8h, and case 4 was normal renal function using 2.5 g q8h. Their concentrations were both up to the PK/PD targets.

Conclusion: TDM results demonstrated that CAZ-AVI steady-state plasma concentration varies among patients with different kidney statuses, providing evidence for the utility of TDM of CAZ-AVI in individualized drug dose adjustment. ARC patients may need more CAZ-AVI daily doses than the standard dose.

CD11b is involved in coxsackievirus B3-induced viral myocarditis in mice by inducing Th17 cells

Viral myocarditis (VMC) caused by coxsackievirus B3 (CVB3) infection is a life-threatening disease. The cardiac damage during VMC is not mainly due to the direct cytotoxic effect of the virus on cardiomyocytes but mostly involves the induction of immune responses. Integrin CD11b plays an important role in immune response, for instance, in the induction of Th17 cells. However, the role of CD11b in the pathogenesis of VMC remains largely unknown. In the present study, a mouse model of VMC was established by CVB3 infection and CD11b was knocked down in the VMC mice by transfection with siRNA-CD11b. The expression of CD11b and IL-17 in heart tissues, frequency of Th17 cells in spleen tissues and serum IL-17 levels were measured using quantitative RT-PCR, Western blot, immunohistochemistry, flow cytometry and ELISA. Results showed that CVB3 infection caused the pathological changes in heart tissues with the increases in the following indexes: expression of CD11b and IL-17 in heart tissues, frequency of Th17 cells in spleen tissues and serum IL-17 levels. The expression of CD11b was positively correlated with IL-17 expression in heart tissues. Depletion of CD11b attenuated the damage caused by CVB3 and decreased the frequency of Th17 cells in spleen tissues as well as in IL-17, IL-23 and STAT3 expression in heart tissues. In summary, our findings reveal that disruption of CD11b function reduced CVB3-induced myocarditis, suggesting that CD11b may be a novel therapeutic target for VMC.

Novel Bithiophene Dimers from Echinops latifolius as Potential Antifungal and Nematicidal Agents

Three novel dimeric bithiophenes, echinbithiophenedimers A-C (1-3), along with two known thiophenes, 4 and 5, were obtained from Echinops latifolius, and their structures were identified through extensive spectroscopic analysis and electronic circular dichroism calculations. Compounds 1-3 possessed new carbon skeletons; they are dimeric bithiophenes with 1 and 2 featuring an unprecedented 1,3-dioxolane ring system and 3 featuring an unusual 1,4-dioxane ring. These compounds are the first examples of bithiophene dimers furnished by different cyclic diethers. Dimeric bithiophenes 1-3 had good antifungal activities against five phytopathogenic fungi, and compound 3 showed excellent activity against Alternaria alternate and Pyricularia oryzae, with a minimal inhibitory concentration value of 8 μg/mL, which was close to or higher than that of carbendazim. Moreover, its effect on the mycelial morphology was observed by scanning electron microscopy. Compounds 1-3, which were demonstrated to be nonphototoxic thiophenes, exhibited better nematicidal activity than the commercial nematicide ethoprophos against Meloidogyne incognita. This study revealed that dimeric bithiophenes containing 1,3-dioxolane or 1,4-dioxane rings could be used as novel antifungal and nematicidal agents for controlling plant fungal and nematode pathogens.

Constituents Leached by Tomato Seeds Regulate the Behavior of Root-Knot Nematodes and Their Antifungal Effects against Seed-Borne Fungi

Germinating seeds can release diverse phytochemicals that repel, inhibit, or kill pathogens such as root-knot nematodes and seed-borne fungi. However, little is known about the composition of these phytochemicals and their effects on pathogens. In this study, we demonstrated that tomato seed exudates can attract the nematode Meloidogyne incognita using a dual-choice assay. Eighteen compounds were then isolated and identified from the exudates. Of these, esters (1-3), fatty acids (4-6), and phenolic acids (10-12) were proven to be the signaling molecules that facilitated the host-seeking process of second-stage juveniles (J2s) of nematodes, while alkaloids (17 and 18) disrupted J2s in locating their host. Furthermore, some phenolic acids and alkaloids showed antifungal effects against seed-borne fungi. In particular, ferulic acid (12) showed obvious activity against Aspergillus flavus (minimum inhibitory concentration (MIC), 32 μg/mL), while dihydrocapsaicin (17) showed noticeable activity against Fusarium oxysporum (MIC, 16 μg/mL). Overall, this study presents the first evidence that M. incognita can be attracted to or deterred by various compounds in seed exudates through identification of the structures of the compounds in the exudates and analysis of their effects on nematodes. Furthermore, some antifungal compounds were also found. The findings of this work suggest that seed exudates are new source for finding insights into the development of plant protective substances with nematocidal and antifungal effects.

[Genetic and clinical analysis of children with early-onset epilepsy encephalopathy caused by KCNT1 gene mutation]

Objective: To study the mutational characteristics of KCNT1 and its clinical features in children with early-onset epileptic encephalopathy. Methods: Retrospective analysis of clinical data of 175 children with early onset epilepsy from the Department of Pediatrics at Peking University First Hospital from January 2012 to December 2017. Gene-based analysis was performed on children with targeted capture second-generation sequencing and the source of mutations was verified by PCR-Sanger. The clinical features of children with KCNT1 mutation were summarized. Results: In 175 infants with early-onset epileptic encephalopathy, 6 children were found to have KCNT1 mutations, all of which were new mutations with an overall mutation rate of 3.4% (6/175). All the mutations were missense mutations. The age of onset was from 2 days to 32 days. Five children were diagnosed with epilepsy of infancy with migrating focal seizure, one case was diagnosed with epilepsy, focal seizures, focal seizures with generalization. A total of 6 children were treated with multi-antiepileptic drugs. The disease in 4 patients were partially controlled, while in 2 patients, the disease was not significantly alleviated. One patient died of "severe pneumonia" at one year and 4 months of age. Then, four cases were treated with quinidine. The seizure frequency had no change in 3 cases, the frequency decreased and then relapsed in 1 case. The case once ketogenic diet and failed. Ketogenic diet treatment was applied to 5 cases, no significant effect was achieved. All the 6 patients had severe developmental delay. They could not sit alone, follow the light and objects and had no language. Conclusions: The mutation of KCNT1 gene is mainly de novo. The onset of the disease was early, and mostly occurs in neonate and early infancy. The main seizure type was epilepsy of infancy with migrating focal seizure. Patients usually had severe psychomotor developmental delay. Antiepileptic drugs are ineffective. The efficacy of quinidine was not significant. Though, it still need studies on a large sample.

The prevalence and spectrum of alpha and beta thalassaemia in Guangdong Province: implications for the future health burden and population screening

AIM

Thalassaemia is a good candidate disease for control by preventive genetic programmes in developing countries. Accurate population frequency data are needed for planning the control of thalassaemia in the high risk Guangdong Province of southern China.

METHODS

In total, 13397 consecutive samples from five geographical areas of Guangdong Province were analysed for both haematological and molecular parameters.

RESULTS

There was a high prevalence of carriers of alpha thalassaemia (8.53%), beta thalassaemia (2.54%), and both alpha and beta thalassaemia (0.26%). Overall, 11.07% of the population in this area were heterozygous carriers of alpha and beta thalassaemia. The mutation spectrum of alpha and beta thalassaemia and its constitution were fully described in this area. This study reports the true prevalence of silent alpha thalassaemia in the southern China population for the first time. In addition, two novel mutations that give rise to alpha thalassaemia, one deletion resulting in beta thalassaemia, and a rare deletion (--(THAI) allele) previously unreported in mainland China were detected. The frequency of the most common mutation, the Southeast Asian type of deletion (--(SEA), accounting for 48.54% of all alpha thalassaemias) was similar to the total of two alpha(+) thalassaemia deletions (-alpha(3.7) and -alpha(4.2), accounting for 47.49% of alpha thalassaemia).

CONCLUSION

Both alpha and beta thalassaemia are widely distributed in Guangdong Province of China. The knowledge gained in this study will enable the projected number of pregnancies at risk to be estimated and a screening strategy for control of thalassaemia to be designed in this area.

Epidemiological and aetiological evidence for transmission of Lyme disease by adult Ixodes persulcatus in an endemic area in China

Involvement of adult Ixodes persulcatus ticks in the transmission of Lyme disease in Hailin County, Heilongjiang Province, China, is reported. In 1986 from April through August adult I. persulcatus was the dominant tick in this endemic area with an infection rate of 43% for the Lyme disease spirochaete, Borrelia burgdorferi. The incidence of Lyme disease cases presenting the symptom of erythema chronicum migrans (ECM) within this area was correlated with the seasonal abundance of adult I. persulcatus and the number of people bitten by ticks. The frequency of ECM formation in all age groups varied and was associated with the frequency of tick bites. In addition, a strain of B. burgdorferi was isolated from a pool of six female I. persulcatus collected from this area. We demonstrate that the seasonal abundance of adult I. persulcatus and its frequent attachment to humans result in the spring and summer transmission of Lyme disease in this endemic area. The role of immature I. persulcatus in Lyme disease transmission is apparently minimal.

Clinical manifestations and epidemiological characteristics of Lyme disease in Hailin county, Heilongjiang Province, China

Clinical manifestations and epidemiological characteristics of Lyme disease in Hailin county, Heilongjiang Province, China have been reported. The clinical picture of erythema chronicum migrans (ECM) is variable. ECM in the form of annular erythematous patch is uncommon. It is an extensive and indurated lesion. In some instances, a vesicle or necrosis appears in the center of the lesion. Secondary erythema may present in some patients. The neurologic abnormalities consist of meningitis, facial palsy, and polyneuritis. Cardiac abnormalities are rare. In addition, there were cases with lymphadenosis benigna cutis (LABC), which had heretofore only been reported in Europe. The attack rate of ECM is 8.4%. There was a significant sex difference, and most cases occurred in May and June. All patients had a history of tick bite. The prevalence rates of neurologic abnormalities and arthritis were 4.6% and 6.6%, respectively. Three strains of spirochete that are closely related to Borrelia burgdorferi were isolated from Ixodes persulcatus ticks and facial palsy patients. From the above results it is concluded that a focus of Lyme disease exists in this region.