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Objective To investigate the microbiota composition and diversity between autogenous and anautogenous Culex pipiens pallens, so as to provide insights into unraveling the pathogenesis of autogeny in Cx. pipiens pallens. Methods Autogenous and anautogenous adult Cx. pipiens pallens samples were collected at 25 ℃, and the hypervariable regions of the microbial 16S ribosomal RNA (16S rRNA) gene was sequenced on the Illumina NovaSeq 6000 sequencing platform. The microbiota abundance and diversity were evaluated using the alpha diversity index, and the difference in the microbiota structure was examined using the beta diversity index. The microbiota with significant differences in the abundance between autogenous and anautogenous adult Cx. pipiens pallens samples was identified using the linear discriminant analysis effect size (LEfSe). Results The microbiota in autogenous and anautogenous Cx. pipiens pallens samples belonged to 18 phyla, 28 classes, 70 orders, 113 families, and 170 genera, and the dominant phyla included Proteobacteria, Bacteroidetes, and so on. At the genus level, Wolbachia was a common dominant genus, and the relative abundance was (77.6 ± 11.3)% in autogenous Cx. pipiens pallens samples and (47.5 ± 8.5)% in anautogenous mosquito samples, while Faecalibaculum (0.4% ± 0.1%), Dubosiella (0.5% ± 0.0%) and Massilia (0.5% ± 0.1%) were specific species in autogenous Cx. pipiens pallens samples. Alpha diversity analysis showed that higher Chao1 index and ACE index in autogenous Cx. pipiens pallens samples than in anautogenous samples (both P values > 0.05), and lower Shannon index (P > 0.05) and Simpson index (P < 0.05) in autogenous Cx. pipiens pallens samples than in anautogenous samples. LEfSe analysis showed a total of 48 significantly different taxa between autogenous and anautogenous Cx. pipiens pallens samples (all P values < 0.05). Conclusion There is a significant difference in the microbiota diversity between autogenous and anautogenous Cx. pipiens pallens.
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Objective To investigate the molecular characteristic of fluoroquinolone resistant Streptococcus agalactiae (GBS) isolates in Suzhou.Methods Totally 46 fluoroquinolone resistant GBS strains were collected,and then subjected into PCR and two resistance genes were sequenced and their high frequency mutation sites,gyrA and parC were analysed.Results Among these isolates,the most frequent gyrA mutation was gyrA_S81L (TCA→TTA),which displayed 93.4％ (43/46) with substituted at No.81 site of amino acid from Ser to Leu.However,the most frequent parC mutation was mutated at No.79 site of amino acid from Ser to Tyr orPhe,with two mutations parC_S79Y (73.9％,34/46) and parC_S79F(17.4％,8/46).The analysis showed that the major mutation patterns are gyrA_S81L with parC_S79Y (73.9％,34/46),gyrA_S81L with parC(13.0％,6/46).Conclusion The most frequent mutations of fluoroquinolone resistant gene in Suzhou are gyrA and parC and the major mutation patterns are gyrA_S81L/parC_S79Y and gyrA_S81L/parC_S79F.
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OBJECTIVE:To provide reference for rational drug use in clinic and nosocomial infection control. METHODS:Acinetobacter baumannii(AB)were collected from our hospital during Jan. 2014-Jun. 2017. Drug sensitivity tests were conducted by using K-B method and MIC method. Drug-resistance genes of multidrug-resistant Acinetobacter baumannii(MDR-AB)were amplified by PCR,and compared with GenBank database by using Blast comparison. RESULTS:A total of 1 758 strains of AB were detected,and mainly came from sputum and throat swab(65.24%),followed by urine(18.49%). These infected patients were mainly distributed in the departments of ICU(38.51%)and respiratory medicine(24.00%),respectively. Drug resistance of clinical isolated AB to most commonly used antibiotics were more than 40%,such as compound sulfamethoxazole,piperacillin sodium and tazobactam sodium,gentamicin,cefepime,levofloxacin,minocycline,imipenem,etc.;it had increased year after year. Drug resistance to colistin was lower than 5% and decreased year by year.A total of 673 strains of MDR-AB were detected, and detection rates were 22.77%,29.82%,52.09%,54.33%,respectively.Among 110 strains of MDR-AB,detection rates of TEM, AmpC,IMP,VIM,OXA-23,OXA-24,OXA-51,aac(6′)-Ⅰ,aac(3)-Ⅰ,ant(3″)-Ⅰ,anmA,gyrA,parC gene were 97.27%, 91.82%,49.09%,12.73%、90.91%,12.73%,98.18%,34.55%,60.91%,89.09%,87.27%,77.27%,82.73%,respectively. Results of Blast comparison showed that point mutation occurred in 83rd and 121st base of gyrA gene,144th base of parC gene. CONCLUSIONS:AB mainly come from sputum and throat swab specimens in our hospital,and infected patients are mainly distributed in the departments of ICU and respiratory medicine. Drug resistance is serious,and the detection rate of MDR-AB is increased year by year. Main genes of multidrug-resistant strains mainly include TEM,AmpC,OXA-23,OXA-51,ant(3″)-Ⅰ, anmA,etc.,and mutation of gyrA and parC gene are found. It is necessary to strengthen the management of classification use of antibiotics and strengthen the monitoring of AB drug resistance. According to the results of drug sensitivity test,antibiotics are selected rationally to prevent or delay planting and cross transmission of AB-resistant strain.
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Objective To investigate the clinical distribution of carbapenem-resistant Enterobacteriaceae(CRE)strains separated in this hospital and the situation of its production of carbapenem enzyme.Methods The production of carbapenem enzyme by CRE strains was confirmed by using modified Hodge test,the situation of the production of metallo-beta-lactamases by CRE strains was screened by using imipenem-EDTA double-disk synergy test,and the clinical distribution of CRE strains was retrospectively ana-lysed.Results 37 strains of CRE isolated in this laboratory were screened by using instrument method and verified by using disk diffusion (K-B)method.It showed an increasing trend from 2012 to 2014 in the amount of CRE strains.In terms of bacterial spe-cies,K.pneumonia(1 6 strains)was the main kind of carbopenems-resistant strains,followed by E.coli(6 strains),Ser.marcescens(6 strains)and E.cloacae(4 strains).CRE strains were mainly isolated from geriatric ward and intensive care unit(ICU).Sputum,u-rine and blood specimen were key sources of CRE strains.Modified Hodge test confirmed that 36 strains of CRE were the strains that can produce carbapenemase,including 4 strains of K.pneumonia,3 strains of E.cloacae,and 1 strain of E.asburiae,and strains producing metallo-beta-lactamases were confirmed by using imipenem-EDTA double-disk synergy test.Conclusion Elderly patients with underlying diseases are susceptible population of CRE hospital infection and are primary preventive targets.The principal mechanism of carbapenem-resistant CRE strains in this hospital is the production of carbapenemase and production of metallo-β-lac-tamases in a small number of strains.
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Objective To analyze the related risk factors of neonatal Streptococcus agalactiae infection and sensitivity of antibac‐terials ,in order to provide for provide evidence for the prevention and treatment of neonatal infection .Methods A total of 1 200 neonatal blood ,gastric juice ,pus specimens ,and maternal reproductive tract specimens were collected from Jan .2013 to Dec .2013 for bacterial culture and drug sensitive test .And clinical data about types of neonatal diseases ,maternal infection status ,mode of de‐livery ,medication in late pregnancy ,situation of neonatal death were retrospectively analyzed .Results A total of 80 cases of neo‐nates were infected by Streptococcus agalactiae ,,and the neonates diagnosed with septicemia ,omphalitis ,premature birth ,intrau‐terine infection and aspiration pneumonia were accounted for 8 .75% ,10 .00% ,15 .00% ,22 .50% and 43 .75% ,respectively .The positive rate of Streptococcus agalactiae infection in mother′s reproductive tract specimens was 51 .25% ,and the results of drug sensitive test were consistent with those of neonates .9 cases of cesarean section ,accounted for 11 .25% ;71 cases of natural child‐birth ,accounted for 88 .75% .In the 80 strains of Streptococcus agalactiae ,the sensitivity of vancomycin ,linezolid ,penicillin and ceftriaxone were all 100 .00% ,and resistance rates of Streptococcus agalactiae to erythromycin ,clindamycin and levofloxacin were higher ,and were 77 .50% ,57 .50% and 33 .75% respectively .Conclusion Maternal Streptococcus agalactiae carriers and mode of delivery may be risk factors for neonatal Streptococcus agalactiae infection .Obstetricians should pay attention to routine screening of Streptococcus agalactiae in perinatal pregnant women ,the laboratory should improve the efficacy in detecting Streptococcus aga‐lactiae and provide the results of antibacterials resistance of Streptococcus agalactiae immediately ,in order to provide references for clinical rational drug use .