Objective To investigate the drug resistance genes of Acinetobacter baumanii in some areas of Nanjing City,and to explore the molecular epidemiology characteristics of different antibiotic resistant strains.Methods A total of 75 strains of Acinetobacter baumanii were isolated from three hospitals of Nanjing city from May 2015 to May 2016 and the strains were identified by microbial identification system.Drug resistances of the strains were determined by KB method.The genotypes of strains were analyzed by pulsed field gel electrophoresis,and PCR was used to amplify the resistance genes.The molecular epidemiology of Acinetobacter baumanii was studied.Results Seventy five strains of Acinetobacter baumanii all had high drug resistance to antibiotics except tigecycline and colistin.The rates of resistance to cefepime,ceftazidime,cefotaxime,ciprofloxacin,cefotaxime,tetracycline were all higher than 90％.The strains were mainly divided into 5 types,and the proportion of A type and B type accounted for 42.67％ and 37.33 ％.The positive rates of genes OXA-23,OXA-24,TEM,SHV,CTX-M,IMP-1,IMP-2 and VIM-2 were 81.33 ％,9.33％,66.67％,10.67％,42.67％,26.67％,16.00％ and 21.33％ respectively.Conclusion A type and B type of the Acinetobacter baumanii are the most popular in hospitals of Nanjing,and the strains are multiple drug resistance.The expression of main resistance genes OXA-23 and TEM strains may be the main mechanism for the higher resistance of the bacteria to antibiotics and β-amide antibiotics.

Objective To investigate the genetic features related to drug-resistance of a strain of pan-drug resistant Acinetobacter baumannii. Methods The susceptibilities to 15 antibacterial agents were detected in Acinetobacter baumannii by K-B paper diffusing method. A strain of pan-drug resistant Acinetobacter baumannii was selected. The drug-resistant genes of the selected strain were amplified by polymerase chain reaction (PCR) , including 15 extended-spectrum β-lactamase genes, 3 metal β-lactamase genes, 2 AmpC enzyme genes, 7 aminoglycoside modifying enzyme genes and the genetic markers of integron I and transposons. Results The strain was resistant to 14 antibacterial agents except cefoperazone sodium/ sulbactam. β-lactamases genes ( TEM, OXA-23 and ADC) , aminoglycosides modification enzyme genes [aac(3)- I , aac(6')- I b and ant(3")- I ] , integron I qacEAi-sull and transposon tnpU were positive in PCR amplification. A new subtype of AmpC (chromosome) desoxyribonucleic acid ( DNA) was detected. Conclusion Acinetobacter baumannii is of high resistance to most antibacterial agents, and the mechanisms of the resistance are complex.

OBJECTIVE To study the current status of the AmpC enzyme and ?-lactamases genes for multi-resistant Acinetobacter baumannii isolates in clinic in Nanjing.METHODS The samples of 20 multi-resistant A.baumannii isolates were collected from Jul 2007 to Oct 2007 from the patients in hospitals of Nanjing.To determine the sensitivity to the 11 antibacterials by using a broth induction method,and two kinds of AmpC enzyme genes and eighteen kinds of ?-lactamases genes of multi-resistant A.baumannii analyzed by polymerase chain reaction(PCR).RESULTS In all of the 20 A.baumannii isolates,the AmpC genes of chromosome type were found in 14 isolates(70.0%),there were the AmpC genes of plasmid type in 1 isolate(5.0%),the TEM genes in 12 isolates(60.0%),the SHV genes in 1 isolate(5.0%),CTX-M-1 genes in 2 isolates(10.0%),OXA-23 genes in 1 isolate(5.0%),and OXA-24 genes in 1 isolate(5.0%),respectively.The OXA-24 genes from No.9 isolate was the type of OXA-72 after DNA sequencing.The amino acid sequence translated by AmpC genes of chromosome type from No.16 and No.17 isolates was the new subtype.CONCLUSIONS The A.baumannii has not only TEM,VEB,GES,IMP,VIM,OXA-10 and OXA-23 genes,but also the type of chromosome and plasmid of AmpC,SHV,CTX-M-1 and OXA-24 genes in Nanjing.It is the first time that activity of AmpC enzyme and the genotype of chromosome and plasmid of AmpC enzyme for matching are tested at the same time.

Objective To investigate the resistance-mechanism of the carbapenems-resistant Klebsiella pneumoniae isolated from clinical.Methods The clinical isolates of carbapenems-resistant Klebsiella pneumoniae from top three comprehensive hospitals of Nanjing area were examined by 40 beta-lactamase,porin-coding genes and linkage of KPC-ISKpn6 using PCR method,the PCR positive results were picked out for sequencing and sequencing BLAST search for comparison analysis.Results Twenty-four strains of carbapenems-resistant Klebsiella pneumoniae were detected,the positive rate of A beta-lactamase TEM-1 and SHV was 100％ (24/24),KPC-2 and LAP-2 was 95.8％ (23/24),45.8％ (11/24) respectively,and C beta-lactamase DHA was 4.2％ (1/24).Meanwhile,the positive detection rates of KPC-ISKpn6 linkage was 95.8％ (23/24),and the mutation rate of porin-coding genes ompK35 and ompK36 were up to 95.8％ (23/24) and 100％ (24/24).Conclusion High incidence of beta-lactamase TEM-1,SHV,KPC-2 and LAP-2 was found in the group of Klebsiella pneumoniae isolates,and carbapenems-resistant of which was primarily due to the high carrying rate of KPC-2 and the high mutation rate of porin-coding genes ompK35 and ompK36.The Insertion sequence ISKpn6 may be involved in the KPC-2 gene mediated-expression.

Objective To prepare rat models of liver stagnation syndrome constipation-type irritable bowel syndrome(IBS-C)using single and multi-factor modeling method with different indicators,to provide ideal experimental animal models of IBS-C.Methods Forty-two SD rats were divided randomly into blank(Normal),cold-water gavage(Cold),restraint(Restrain),tail-clamping(Tail),cold-water gavage + restraint(C + R),and cold-water gavage + tail-clamping groups(C + T).Body weight,food intake,water intake,and survival status,as well as open-field behavior,fecal Bristol score,visceral sensitivity,and small intestine propulsion were observed in each group during the modeling period.Pathological changes in the rat colon were observed by hematoxylin and eosin staining,and the serum and colon contents of 5-hydroxytryptamine(5-HT)and vasoactive intestinal peptide(VIP)were determined by enzyme-linked immunosorbent assay.Results The body weight in each group decreased after modeling(P<0.05,P<0.01),the food and water intakes decreased,and serum 5-HT levels increased.The number of fecal particles and Bristol score decreased while the colon 5-HT content increased in the Cold group(P<0.05,P<0.01);the total distance and average speed of the restraint group in the open field decreased(P<0.01);the preference for sugar water in the Tail group decreased(P<0.01);the preference for sugar water,total open-field distance,small intestine propulsion rate,defecation particles,and Bristol score all decreased,while the colon 5-HT content increased and the VIP content decreased in the C + T group(P<0.05,P<0.01);and the total distance,average speed,and VIP content in the colon decreased in the C + R group(P<0.05).Except for the Tail group,all the model groups showed visceral hypersensitivity(P<0.05,P<0.01)compared to the blank group at various pressure values on days 7 and 14 of modeling.Pathological observations showed no significant inflammatory cell infiltration or pathological changes in any of the model groups.Conclusions The combination of ice-water gastric lavage and tail clamping can be used to establish a rat model of liver depression syndrome in IBS-C.This may be the best of the five tested method,and the resulting model may lay the foundation for further systematic and in-depth research into the mechanism of traditional Chinese medicine in preventing and treating IBS-C.