Objective To investigate the types ,specimen types ,department distribution and drug resistance of multi‐drug resist‐ant bacteria in our hospital during the recent 5 years to provide the scientific guidance for the clinical treatment ,prevention and con‐trol of multi‐drug resistant bacteria .Methods The specimens of laboratory bacterial culture positive during 2011-2015 were col‐lected ,and analyzed on the types ,proportion and drug resistance situation of multi‐drug resistant bacteria and their distribution in clinical specimens and clinical departments .Results A total of 2 568 strains of multi‐drug resistant bacteria were isolated and ac‐counted for 37 .41% the positive specimens ,in which top 5 bacteria were Escherichia coli ,Acinetobacter baumannii ,Staphylococcus aureus ,Klebsiella pneumoniae and Pseudomonas aeruginosa;the sputum ,midstream urine ,blood and secretions had the higher posi‐tive rate of multi‐drug resistant bacteria ,while the secretions from the catheter tip and ear discharge had the lower positive rate(P<0 .05);the multi‐drug resistant bacteria had difference among different departments ,in which ICU ,respiratory department and sur‐gery department were highest ,while the lowest was in the spleen and stomach department and breast department ;the resistance of multi‐drug resistant bacteria occurred over a wide range ,which had higher resistance to beta lactam and aminoglycosides and had higher sensitivity to compound antibacterial drugs such as sulfamethoxazole antibiotics and enzyme inhibitors .Conclusion Multi‐drug resistant bacteria are more and more common in clinic .The positive rate is increased year by year .The drug resistant strains widely distributed .The clinical departments should pay high attention to .Rational and scientific use of antibacterial drugs ,strict control of multi‐drug resistant bacterial spread and strength of the patients′isolation have an important significance to effectively prevent and control the multi‐drug resistant bacterial spread .

Objective To explore the isolation, culture and identification of mouse amniotic fluid-derived mesenchymal stem cell (AF-MSC). Methods The uteruses of pregnant mice were obtained under sterile conditions. The amniotic fluid was collected, filtered and centrifuged, and the precipitated cell mass was cultured and passaged. The morphology of AF-MSC was observed and the proliferation characteristics of AF-MSC were analyzed. The surface markers of AF-MSC were identified by flow cytometry. The osteogenic, chondrogenic and adipogenic differentiation capability of AF-MSC and cell vitality after cryopreservation and resuscitation were evaluated. Results The mouse AF-MSC was seen in typical spindle shape, and vortex structure could be observed when the cell confluency exceeded 80%. No evident latency was noted in the passage and culture of mouse AF-MSC. After 2-3 d culture, AF-MSC proliferated in the logarithmic growth stage with the fastest growth rate, which was slowed down and entered into the plateau period. AF-MSC expressed stem cell antigen (Sca)-1, CD29 and CD44 rather than CD34 and CD45. After the osteogenic differentiation of mouse AF-MSC, the mineralized crystals were stained in dark red spots by Alizarin red S staining. After chondrogenic differentiation, the secreted acid mucopolysaccharide was stained in light blue by Alcian blue. After adipogenic differentiation, cytoplasmic lipid droplets were stained in red by oil red O staining. After cryopreservation and resuscitation, the survival rate of AF-MSC exceeded 95%, and the growth status was excellent. The proliferation ability at 6 d was significantly better than that before cryopreservation (P < 0.05), and the proliferation ability at other time points did not significantly differ from that before cryopreservation (all P > 0.05). Conclusions Mouse AF-MSC may be successfully isolated with convenient procedure and the low cost. In addition, the isolated AF-MSC may be purified along with the increasing times of passage. Cryopreservation does not affect the proliferation ability of AF-MSC.