Pathogenic characterization of Klebsiella pneumoniae resistant to carbapenems and polymyxin / 中华预防医学杂志

Objective: Analysis and investigation of pathogenic characteristics of polymyxin-and carbapenem-resistant Klebsiella pneumoniae (PR-CRKP). Methods: A total of 23 PR-CRKP strains isolated from clinical specimens from the General Hospital of Southern Theater Command from March 2019 to July 2021 were retrospectively collected, Whole-genome sequencing was performed on 23 PR-CRKP strains, resistance genes were identified by comparison of the CARD and the ResFinder database, high-resolution typing of PR-CRKP strains was analyzed by core genomic multilocus sequencing (cgMLST) and single nucleotide polymorphism (SNP); polymyxin resistance genes were determined by PCR and sequencing. Results: All PR-CRKP strains were KPC-2 producing ST11 types. cgMLST results showed that the evolutionary distance between the PR-CRKP strains and Klebsiella pneumoniae in mainland China was 66.44 on average, which is more closely related than foreign strains; the 23 PR-CRKP strains were divided into 3 main subclusters based on SNP phylogenetic trees, with some aggregation among Clade 2-1 in the isolation department and date. The two-component negative regulatory gene mgrB has seven mutation types including point mutations, different insertion fragments and different insertion positions. Conclusion: The close affinity of PR-CRKP strains indicate the possibility of nosocomial clonal transmission and the need to strengthen surveillance of PR-CRKP strains to prevent epidemic transmission of PR-CRKP.

Echinacoside and Cistanche tubulosa(Schenk)R.wight have male reproductiveprotection effect by targeting hypothalamic and rogen receptor / 中国药理学与毒理学杂志

OBJECTIVE Cistanche deserticola Y. C. Ma is an official plant that grows in arid or semi-arid areas.Our early work demonstrated that Cistanche extracts protect against sperm damage in mice under bisphenol A induced reproductive damage. Echinacoside (ECH)is one of the major active components. The present study investigated the mechanisms behind the possible protective effects of ECH against oligoasthenospermia in rat and identified the interaction between ECH and AR. METH-ODS The distribution of ECH was assayed by HPLC,the quantity and quality of sperm was evaluated and hormone levels were determined by radioimmunosorbent assay. The levels of androgen receptor (AR)and key steroidogenic-related genes were reduced as determined by Western blotting and qPCR analysis.The interaction between ECH and AR were evaluated by fluorescence localization assay,indi-rect ELISA and molecular docking. RESULTS ECH significantly increased the quantity of sperm and secretions of luteinizing hormone and testosterone.ECH was distributed to the hypothalamus but not in the testes.ECH combined with hypothalamic AR in the pocket of Met-894 and Val-713 to inhibit transfer of AR from the cytoplasm to nuclei in the hypothalamus.While negative feedback of sex hormone regula-tion was inhibited, positive feedback was stimulated to increase the secretion of luteinizing hormone and testosterone subsequently enhancing the quantity of sperm. C. militaris significantly alleviated the BPA-induced reproductive damage by increasing testicular superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and glutathione (GSH); as well as by reducing serum malondialdehyde (MDA). C. militaris not only obviously enhanced the levels of serum LH and T, but it also improved the sperm count and motility compared to the BPA-treated group.CONCLUSION C.militaris and ECH protect the BPA induced reproductive damage.ECH blocks AR activity in the hypothalamus to increase the quantity of sperm and protect against oligoasthenospermia in rats.

Reversal of ciprofloxacin resistance by efflux pump inhibitors using Caenorhabditis elegans-extensively drug-resistant Acinetobacter baumannii infection model / 中国感染控制杂志

Objective To establish an extensively drug-resistant Acinetobacter baumannii (XDR-AB) infection model using Caenorhabditis elegans (C.elegans),and evaluate the effect of efflux pump inhibitors(EPIs) on reversal of ciprofloxacin resistance in XDR-AB.Methods XDR-AB infection model of C.elegans was established,six EPIs(CCCP,PAβN,NMP,omeprazole,reserpine,and verapamil)combined with ciprofloxacin were used to treat the infected model,the survival rate of C.elegans was recorded to evaluate the in vivo activities of drugs,toxicity test and in vitro drug susceptibility test were also performed.Results Lethal effect of different concentrations of XDR-AB on C.elegans was varied,5 × 106 CFU/mL of XDR-AB was selected to infect C.elegans.C.elegans survival test showed that survival curves of C.elegans infected with XDR-AB for 3 hours and curves of control group (polymixin B was added) were not significantly different (x2 =3.154,P＞0.05);compared with control group,survival curves of C.elegans infected with XDR-AB for 6 hours or 9 hours were significantly different (both P＜0.001),but 6 hours and 9 hours were not significantly different(x2 =0.669,P＞0.05),6 hours was chosen as the duration of infection,36 hours was appropriate for the duration of antimicrobial therapy.Ciprofloxacin with EPIs for infection model revealed that low concentration of PAβN,NMP,omeprazole,and reserpine could improve the survival rate of C.elegans by 30％-40％,15％-20％,20％-30％,and 20％ respectively,high concentration of verapamil could improve the survival rate of infected C.elegans by about 30％.In vitro susceptibility test and toxicity test results showed that ciprofloxacin combined respectively with CCCP,omeprazole,and verapamil could reduce minimum inhibitory concentration(MIC) to the original 1/4,combined respectively with PAβN,NMP,and reserpine could reduce MIC to the original 1/2,CCCP had the best bacterial inhibitory effect in vitro,but the toxicity was large,and was not suitable for the study of pharmacodynamics in vivo.Conelusion The infection model of C.elegans XDR-AB is initially and successfully established,which is used to evaluate the efficiency of six EPIs for reversing ciprofloxacin resistance.