ObjectiveTo compare the differences between clinical and environmental sources of Acinetobacter baumannii （AB） at a tertiary hospital in Guangzhou in terms of molecular epidemiological characteristics， antimicrobial resistance， disinfectant tolerance， virulence and the distribution of related genes， as well as plasmid epidemiological characteristics； and to assess the association between environmental and clinical strains and the potential transmission risks associated with environmental contamination. MethodsA total of 118 clinical and 102 environmental AB isolates were collected from a tertiary hospital in Guangzhou between 2024 and 2025. Species identification was performed using mass spectrometry and 16S rRNA sequencing； minimum inhibitory concentrations （MICs） for eight antimicrobial agents were determined using the agar dilution method； biofilm formation capacity was assessed using the crystal violet staining method； A Galleria mellonella infection model was used to evaluate the virulence； whole-genome sequencing was employed for multilocus sequence typing （MLST）， phylogenetic analysis， and studies on the distribution of resistance， disinfectant resistance and virulence genes， and plasmid screening. ResultsA total of 38 known ST types were identified among the 220 AB strains， with ST2 and ST40 being the predominant lineages. Antimicrobial susceptibility testing revealed that the clinical infection group exhibited resistance to minocycline， imipenem and other antibiotics， as well as the tolerance levels to the disinfectants triclosan and benzalkonium bromide， were generally higher than those in the environmental group （P＜0.001）， and the detection rates of drug resistance genes such as bla_OXA-23 and adeB all exceeded 70.0%. Statistical analysis confirmed that the MIC values of TCS and BAB were significantly positively correlated with various antibiotic resistance phenotypes （P＜0.05）. In biofilm experiments， the proportion of strong biofilm-forming strains in the environmental group （64.7%） was significantly higher than that in the clinical infection group （11.9%；χ²=69.06， df=2， P＜0.000 1）， and the mortality rate of the strains increased with enhanced biofilm-forming ability. Furthermore， a total of 41 plasmid lineages and 219 insertion sequences were detected； ISs such as IS1006 and IS1007 were frequently co-occurring with resistance and virulence genes including bla_OXA-23 and katA. ConclusionsThe predominant lineages of AB in this tertiary hospital were ST2 and ST40. The clinical infection group generally exhibits higher levels of antibiotic resistance and tolerance to disinfectants compared to the environmental group， while biofilm-forming ability differs ： the environmental group dominates in strong biofilm formation， and the clinical group dominates in weak to moderate biofilm formation. Plasmids and ISs may be involved in the co-occurrence and dissemination control strategies and for the molecular epidemiological surveillance of multidrug-resistant bacteria.

Objective To establish the in vitro biofilm model of Laribacter hongkongensis(LH),to analyze the type Ⅰ integron related genes carried by LH and to investigate the mechanism of LH resistance to quinolones.Methods The biofilm forming abilities of LH clinical isolates were determined by Giemsa staining qualitative method and by crystal violet staining semi-quantitative method.The sensitivity of LH to norfloxacin,ofloxacin,levofloxacin,ciprofloxacin and lomefloxacin in both planktonic and biofilm conditions were dectermined by broth microdilution susceptibility tests.Type I integron related genes carried in 18 LH strains resistant to quinolone were detected by PCR amplification method.Results The detection results by Giemsa staining demonstrated that 36 strains in 55 LH clinical isolates formed visible biofilm,and the biofilm formation rate was 65.4%(36/55).In the biofilm forming ability detected by crystal violet staining semi-quantitative method,OD560≤0.15 was in 8 strains of LH,0.150.20 in 7 strains respectively.The levels of minimal biofilm inhibitory concentration in norfloxacin,ofloxacin,levofloxacin,ciprofloxacin and lomefloxacin to LH were respectively higher than the minimal inhibitory concentration(MIC) in the corresponding floating bacteria(P<0.05).Among 55 strains of LH,18 strains were resistant to quinolones,the resistance rate was 32.7%,and the type I integron in 18 strains of LH carried the drug resistant genes,these drug resistant genes played the drug resistance role in corresponding bacterial strains.Conclusion Drug resistance gene formation and widespread of LH may be associated with type I integron.

Objective To evaluate the clinical effect of retrievable esophageal covered metal internal stent in treating patients with achalasia.Methods Under DSA guidance,peroral"Z-type"double horn covered metal internal stent implantation was performed in 16 patients with achalasia.Esophagography was carried out about 28 days after the procedure and the stent was retrieved.Results Of 16 cases,the stent fell off into the stomach two weeks after the operation in one.And the stent was successfully replaced after it was taken out.The placed stent was successfully retrieved in all cases 28 days after the treatment.No serious complications occurred.All the patients were followed up for 3 months to 3 years.During the follow-up period restenosis of the esophagus developed in two cases(at one and 1.5 years respectively),and the restenosis degree was relived after balloon dilation.Clinically,no esophageal symptoms,such as dysphagia,occurred in all patients.Conclusion As a simple and safe technique,the retrievable esophageal covered metal internal stent implantation is very effective with fewer complications for the treatment of achalasia.Moreover,the technique carries lower restenosis occurrence.

Rabbit bone marrow-derived mesenchymal stem cells(MSCs) are multipotent. We studied the adipogenic and osteogenic differentiation potent using adipogenic supplement (AS) or osteogenic supplement (OS) in vitro. Specific markers of this induced adipogenic and osteogenic lineage were identified. The findings showed that the rabbit MSCs are capable of differentiating into adipogenic and osteogenic lineages spontaneously. On the 21st day, approximately 75% rabbit MSCs were induced to adipogenic or osteogenic cells in medium containing AS or OS, respectively. These results demonstrated that the differentiation of MSCs could be regulated in vitro. The underlying molecular mechanisms of adipogenic or osteogenic differentiation await elucidation.
Adipose Tissue ; cytology ; Animals ; Bone and Bones ; cytology ; Cell Differentiation ; Cell Lineage ; In Vitro Techniques ; Mesoderm ; cytology ; Rabbits ; Stem Cells ; cytology