Gut microbiota-derived short-chain fatty acids ameliorate methamphetamine-induced depression- and anxiety-like behaviors in a Sigmar-1 receptor-dependent manner

Methamphetamine (Meth) abuse can cause serious mental disorders, including anxiety and depression. The gut microbiota is a crucial contributor to maintaining host mental health. Here, we aim to investigate if microbiota participate in Meth-induced mental disorders, and the potential mechanisms involved. Here, 15 mg/kg Meth resulted in anxiety- and depression-like behaviors of mice successfully and suppressed the Sigma-1 receptor (SIGMAR1)/BDNF/TRKB pathway in the hippocampus. Meanwhile, Meth impaired gut homeostasis by arousing the Toll-like receptor 4 (TLR4)-related colonic inflammation, disturbing the gut microbiome and reducing the microbiota-derived short-chain fatty acids (SCFAs). Moreover, fecal microbiota from Meth-administrated mice mediated the colonic inflammation and reproduced anxiety- and depression-like behaviors in recipients. Further, SCFAs supplementation optimized Meth-induced microbial dysbiosis, ameliorated colonic inflammation, and repressed anxiety- and depression-like behaviors. Finally, Sigmar1 knockout (Sigmar1-/-) repressed the BDNF/TRKB pathway and produced similar behavioral phenotypes with Meth exposure, and eliminated the anti-anxiety and -depression effects of SCFAs. The activation of SIGMAR1 with fluvoxamine attenuated Meth-induced anxiety- and depression-like behaviors. Our findings indicated that gut microbiota-derived SCFAs could optimize gut homeostasis, and ameliorate Meth-induced mental disorders in a SIGMAR1-dependent manner. This study confirms the crucial role of microbiota in Meth-related mental disorders and provides a potential preemptive therapy.

A new quantitative 16S rRNA amplicon sequencing method / 生物工程学报

In recent years, 16S rRNA amplicon sequencing technology has been widely used to study human gut microbiota and to detect unknown pathogens in clinical samples. However, its resolution to bacterial population can only reach the relative abundance of genus level, and different factors affect the final bacterial profile, such as sample concentrations, PCR cycle numbers and amplification primers. In order to solve these problems, we developed a quantitative 16S rRNA amplicon sequencing method by combining random tag and internal marker method. The new methods improved the accuracy of human gut microbiota, reduced the impact of experimental operation on the results, and improved the comparability between sequencing and other molecular biological methods.

Analysis of drug resistance of Psendomonas aeruginosa in ICU during 2006-2007 / 国际检验医学杂志

Objective To discuss the drug resistance and the vicissitude of Pseudomonas aerugi-nosa in Intensive Care Unit (ICU), in order to provide basis for rational use of antibiotics in clinic. Methods Identification of bacteria was performed by applying ATB Expression Identification System produced by BioMerieux Company; drug susceptibility tesr was done by using K-B method. The drug resistance of Pseudomonas aeruginosa was compared between ICU and general wards; and then the difference of drug resistance was investigated between 2006 and 2007. Resnlts The more sensitive an-tibiotics to Pseudomonas aeruginosa in ICU of our hospital were as follows, amikacin (resistance rate 6.7%-9.4%), eiprofloxacin (resistance rate 7.7%-24.7%), cefoperazone/sulbactam (resistance rate 11.5%-34%), ceftazidime (resistance rate 11.5%-37.7%), aztreonam (resistance rate 20.2%-40.6%). The drug resistance rate of ICU was higher than that of the general wards, and the drug re-sistance rates to ciprofloxacin, ceftazidime, cefoperazone/sutbaetam,meropenem, imipenem and aztreo-nam in 2007 were significantly higher than those in 2006 (P<0.01). Conclusion The drug resistance rate of Pseudomonas aeruginosa in ICU of our hospital was very high,and it is rising year by year. So it is important to retrospect the results of the drug resistance periodically and provide the up-to-the-mi-nute data of epidemiology and vicissitude of drug resistance.

Application of multiple-locus variable-number tandem repeat analysis(MLVA) for molecular typing of Leptospira interrogans serogroup Icterohaemorrhagiae / 中华微生物学和免疫学杂志

Objective To establish the method of multiple loci VNTR(variable numbers tandem-repeats) analysis (MLVA) for genotyping Leptospira interrogans serogroup ieterohaemorrhagiae . Methods Seven VNTR loci were chosen for genotyping 117 strains of L. interrogans serogroup Icterohaemorrhagiae by PCR-electrophoresis-based VNTR analysis and the results were analyzed by software BioNumerics( Version 4.0). Results One hundred and seventeen isolates of L. interrogans serogroup Icterohaemorrhagiae detec-ted with 7 VNTR loci were classified into three clusters(A,B,C), twenty-eight types were found, type A 11.97% (14/117), type B 0.85% (1/1 17), type C 87.18% (102/117). Diversity Indexes for the loci varied between 0.0831 and 0.8005. Clinical strains isolated from the same geographic area and belonging to the same serogroup shared a common VNTR pattern. Conclusion MLVA could be used to classify and identify Leptospira interrogans preliminarily. With the improvement of technology, this rapid and easy method should greatly contribute to a better knowledge of the epidemiology of Leptospira.