Chinese Journal of Microecology

Objective To explore the antimicrobial resistance of Acinetobacter baumannii and the genotype of multidrug-resistant β-Lactamase producing Acinetobacter baumannii isolated from clinical specimens in order to provide the laboratory information for effective control and treatment of the infectious diseases.Method Kirby-Bauer(K-B) tests were performed to detect the susceptibility of 312 strains of Acinetobacter baumannii to 13 kinds of antimicrobial agents.The genotypes of β-Lactamase producing gene in multidrug-resistant Acometobacter baumannii were detected by multiple PCR amplification and then the DNA products were sequenced.Result The resistance rates of the 312 Acinetobacter baumannii isolates to Imipenam,Cefoperazone/sulbactam and Ticarcillin/clavulanic were 1.0%,30.8% and 31.4%,respectively.The resistance rates to other antimicrobial agents were between 38.5%～80.1%.The positive rates of AmpC,SHV-12,PER-1,CTX-M-9 and TEM-1 among β-Lactamase genes in 120 multidrug-resistant strains were 66.7%(80/120),14.2%(17/120),16.7%(20/120),8.2%(10/120) and 9.2% (11/120),respectively.VER-1,CTX-M-1,CTX-M-2 and OXA genes were not found.There were two different genes in 16 strains,and three different genes in 14 strains.Conclusion Strains that produce AmpC were predominant among Acinetobacter baumannii isolated from clinical specimens and were also multiresistant.

Objective To observe whether Acinetobacter baummannii could form the biofilm(BF).Methods The modified flat-board method and scanning electron microscopy were used to observe whether the BF could form on silicon disk at 24 hours,2 day,3 day,5 day,7 day respechively.Results Acinetobacter baummannii could form BF on silicon disk at the third day.And the bacteria were found to have morphological changed after the BF formation.Conclusion Acinetobacter baummannii can form BF.

Objective To observe the distribution of bacteria and morphologic features of biofilms(BFs) on the surface of endotracheal tubes(ETT) in PICU.Method 35 children undergoing mechanical ventilation(MV) were involved in this study.ETTs were collected at the first time of extubation.After staining with PI and FITC-ConA,the distribution of the bacteria and extracellular polymeric substances(EPS) were observed by confocal laser scanning microscopy(CLSM).Meanwhile,bacteria in BF and the secretions of lower respiratory tract were isolated,cultured and identified,respectively.Result(1)Of 35 ETTs,31 tubes were positive(88.57%).And 17 samples had the same pathogen both in the ETTs and secretions of lower respiratory tract,which accounted for 54.83%of the positive cultures from ETTs.Staphylococcus aureu,Klebsiella pneumoniae,Escherichia coli and Enterobacter cloacae were the main pathogens in BF and the secretions of lower respiratory tract.(2) Observation by CLSM showed that the bacteria were adhered on the surface of the ETTs in 12 hours after intubation;after 48 hours,lots of spherical or clubbed bacteria adhered into clusters,EPS also increased,and the initial BF was formed;After 72 hours,bacteria which encased in mass of EPS aggregated mutually into clumps,and formed mature BF;After more than 7 days the bacteria adhered into lamellars,and there were some microcolonies around mature BF.(3)Of 35 mechanical ventilated children,19 cases had VAP,including 10 in orotracheal intubation and 9 in nasotracheal intubation.Conclusion Bacterial biofilm can form on the surface of ETTs when ventilated.There may be correlation between microbial colonization and BF formation on the surface of ETTs and VAP in children who were intubated and ventilated for a long period.

Objective To learn the fate and dissemination of B.subtilis spores in gastrointestinal tract of broiler.Method Bacillus subtilis spores were fed to 20-day-old AA broilers.The number of Bacillus subtilis spores in faeces and in different parts of gastrointestinal tract of broiler were measured.Result B.subtilis spores were detectable by 3 h after inoculation;the majority of counts occurred within the first 24 h.No B.subtilis were detected in the 120 h samples.The number of B.subtilis spores CFU recovered from the faeces was 200% more than the original inoculum.The results also showed that B.subtilis spores started to germinate and reproduce in the duodenum 2.The live B.subtilis reached to peak in the small intestine 3 and the small intestine 4.Conclusion A proportion of the spores had germinated and undergone one or more rounds of growth and replication,and spores may colonize the small intestine,albeit briefly.

Objective To study the antagonism and mechanism of Lactobacillus Salivarius ssp.salivarius ZDY162a against mytoxin-producing Fusarium.Method Fusarium graminearum and Fusarium oxysporum were adopted as the indicator strains to test the inhibition effect of metabolites of L.salivarius ssp.salivarius ZDY162a on spore germination,spore growth and mycelium growth.Result 10% of the spent culture supernatant(SCS) of L.salivarius ssp.salivarius ZDY162a could inhibit the spores germination of Fusarium graminearum by 83% and Fusarium oxysporum by 50%,respectively.The SCS inhibited remarkably the growth of spores in 24 h and that of mycelia of Fusarium in 96 h.Conclusion Some organic acids produced by L.salivarius ssp.salivarius ZDY162a were probably playing an primarily role in inhibiting the growth of Fusarium graminearum and Fusarium oxysporum.

Poria cocos has been highly valuable in pharmaceutical chemistry,pharmacology and clinical application.The advances in researches of Poria cocos are introduced in this paper.The chemical constituents,the major one of which is polysaccharide,the anti-tumor,immune and pharmacological activities of Poria cocos are involved.And its prospect in application are also discussed to provide evidence for further research.

Since the increasing populations of HIV-infected and immune-compromised patients due to immunosuppressive medical regimens,there was need to develop CD4+ T cell-independent therapeutic strategies to prevent opportunistic infection.There was a well-known inverse relationship between CD4+ lymphocyte count and the risk of pneumocystis infection and other bacterial infection,but the CD4+ T cells does not hold all of the answers to mechanisms of host defense against these infections.CD40 ligand(CD40L) was critical for host defense against pneumocystis as well as other opportunistic infections.To test whether CD40L could prime immune response in the deficiency of CD4+ T cells in mice,chicken ovalbumin(OVA) was used as the model antigen with the addition of CD40L in CD4-depleted mice.Anti-OVA IgG1 and IgG2a were measured by ELISA three weeks after the boost.The result showed significant increases in IgG2a and IgG1 in the CD40L co-transduced group compared to OVA alone.We also observed a significant increase in OVA-specific IFN-γ elaboration in splenocytes after stimulation with the SIINFEKL peptide in both CD4-replete mice and CD4-depleted mice that were co-transduced with CD40L.These data suggest that CD40L can prime both B-cell and CD8+ T-cell responses.

Objective To study intestinal bacteria of Clanis bilineata tsingtauica for purpose of researching its nutritional physiology activities,realizing the intestinal bacteria composition,and finding the utilizable bacteria species.Method Twenty-three strains were isolated from the intestinal of the Clanis bilineata tsingtauica larva by the traditional separation,purification,cultivate methods,and researched their morphology,staining reaction,culture traits,physiological and biochemical reaction.Results 23 different strains,in which Staphylococcus,B.lichenifomis and Propionibacterium were dominant,were isolated.Conclusion The kinds of intestinal microbial flora in the larvae are related with living behavior of Clanis bilineata tsingtauica.The results make a facility for the research of artifical diet of the larva,development and reproductin.

Objective To investigate the effects of mixed feed and corn on the intestinal microbiota diversity of Bama miniature pigs. Method The variety of intestinal microbiota was tested by PCR-DGGE and the difference analysis was performed by 16S DNA.Result The intestinal microbiota of the Bama miniature pigs fed on mixed feed and corn respectively was kindreder and showed some individual differences;the richness and variety index of intestinal flora in Bama miniature pigs had no obvious difference while the evenness degree differed apparently;16S DNA sequencing analysis showed that the respective floras of the mixed feed group and corn group are Coprococcus eutactus,Clostridium bartlettii and Bifidobacterium animalis subsp,Streptococcus infantarius subsp respectively.Conclusion Different foods could result in a variety of intestinal flora of Bama miniature pigs.

Objective To retrospectively analyse the distilbution and drug sensitivity of the strains of yeasts isolated from the gynecologycal inpatients' vaginal secretion.Method 396 strains of yeasts isolated from 5813 gynecologycal inpatients' vaginal secretion were identified by using the AP I-20Aux and ATBFUN GUS.Result The most common isolates in the 396 strains of yeasts were Candida albicans(59.6%),Candida glabrata(21.2%)and joint-Yeastlike(6.6%)respectively;The drug sensitivity to 5-Fluorocytosine(5-FC),Amphotericin B(AMB),Nystatin(NYS),Miconazole(MIC),Econazole Nitrate(ECO),Ketoconazole(KET)were 90.7%,92.7%,96.2%,74.2o%,61.6% and 69.4% respectively.Conclusion Vaginal Candidasis is usually caused by Candida albieans and Candida glabrata.The strains of yeasts isolated are more susceptive to 5-Fluorocytosine(5-FC),amphotericin B(AMB)and Nystatin(NYS)while resistent to zole drugs to various extents.

Objective To investigate the detection rate and genotypic character of extended spectrum beta-lactamases(ESBLs)in isolates from intensive care unit(ICU)in Shenzhen People's Hospital.Method Phenotyic confirmatory test which recommended by CLSI was performed to detect ESBLs in 48 Escherichia coli and Klebsiella pneumoniae isolates,and the ESBL-genotypes were determined by using PCR and DNA sequencing.Result(1)24 in 48 isolates were detected producing ESBLs,with the detection rate of 50%.(2)In all ESBL-producing isolates,93.8% of Escherichia coli and 87.5% of Klebsiella pneumoniae were found harbouring CTX-M gene,72.7% of them were CTX-M-14.Six Klebsiella pneumoniae isolates were found carrying SHV gene,three of them were SHV-11 and the others were SHV-12.And five in these six SHV-type Klebsiella pneumoniae isolates were harbouring CTX-M gene.SHV gene was not detected in Escherichia coli isolates.In all the ESBL-producing isolates,10 strains of Escherichia coli and 2 of Klebsiella pneumoniae were found carrying TEM-1 gene,and one of them carrying only TEM-1 but not the others.Conclusion The detection rate of ESBL is high in isolates from ICU in this hospital,the major genotype of the ESBLs-producing isolates is CTX-M-14.

Two predominant physiological changes would take place during the body aging process,i.e.immunosenescence and oxidative damage.The effect of immunomodulatory and antioxidant activity of probiotics on aging procedure was discussed and investigated.It was proposed that the potential anti-aging function of probiotics was unquestionably correlated with their immune-stimulating and antioxidative activity.Recently,few inspiring studies regarding the anti-aging role of some specific probiotic strains in experimentally senescence-accelerating animals had been reported.The mechanisms of some senescent animal model adopted prevalently at present were also analyzed.It was accentuated that some modified anti-aging screening models engaging key enzyme involved in the aging physiology,e.g.monoamine oxidase which was responsible for the risk of Parkinson disease,as target enzyme in vitro or Caco-2 cells which can reflect the oxidative injures correlated with senescence,should be established and improved.Finally,the candidate probiotic strains with potential anti-aging activity should be further assessed in some well-established experimental animal models to verify the results obtained in vitro as well as to elucidate the mechanism of anti-aging activity objectively.