Objective To study the relation of the porin at the out membrane with resistance to cefoxitin in Enterobacter cloaceae. Methods The extended spectrum beta lactamase(ESBLs) was detected by phenotypic confirmatory test according to NCCLS M100 S9;the beta lactamase and out membrane protein(OMP) was extracted by ultrasonication,the beta lactamase was detected by ultraviolet spectrophotometer,the composition of OMP was analyze by SDS PAGE. Results The 6 strains in 9 strains of Enterobacter cloaceae with resistance to cefoxitin lost 18 kda protein band and did not product hydrolase to cefoxitin and 5 strains was ESBLs positive. 2 strains producing hydrolase to cefoxitin did not lose the 18 kda protein. One strain with resistance to cefoxitin was producing ESBLs but did not defect the 18kda protein band and product hydrolase to cefoxitin. Conclusion The defect of the 18 kda protein band is nearly relation with resistance to cefoxitine in Enterobacter cloaceae.

Objective:To summarize the clinical and genetic characteristics of Potocki-Shaffer syndrome (PSS).Methods:A retrospective study was conducted to analyze the clinical data of 1 patient diagnosed with PSS in the Department of Pediatrics of the Sixth Affiliated Hospital, Sun Yat-Sen University at February 2021.The data analyzed included clinical manifestations, biochemical tests and gene tests.Meanwhile, studies were retrieved from the China National Knowledge Internet database, Wanfang database, and PubMed database from the establishment of the database to December 2021 by taking " Potocki-Shaffer syndrome" " EXT2 gene" " AlX4 gene" and " PHF21A gene" as key words.Besides, genes were searched from the Online Frontal Analysis Mendelian Inheritance in Man.The clinical and genetic features of PSS patients were summarized. Results:The patient was 5 months and 21 days old, male, who was admitted to the hospital due to excessive growth in body mass for the past 3 months.The patient showed mental and motor retardation, overgrowth, concealed penis, hearing loss, and hypotonia.Whole exon sequencing of this patient revealed heterozygous deletions in the Chr11: 44069455-48188946 region, including the deletions of 3 autosomal dominant genes: EXT2, ALX4, and PHF21A.The patient was diagnosed with PSS.A total of 14 articles published in English were collected, involving this boy and other 35 patients.In these patients, 14 cases had point mutations, and 22 cases had large deletions. PHF21A gene variation was detected in 23 cases (dysgnosia in 22 cases, dyskinesia in 21 cases, language development delay in 18 cases). EXT2 gene variation was observed in 22 cases (exostoses in 13 cases). ALX4 gene variation was found in 19 cases (bilateral parietal foramina in 15 cases). Of 36 cases, 27 cases had craniofacial anomalies. Conclusions:The main clinical symptoms of PSS are language and motor developmental delay, intellectual disability, exostoses, bilateral parietal foramina, and craniofacial anomalies, which are closely related to 3 autosomal dominant genes ALX4, EXT2 and PHF21A.Genetic testing facilitates the clinical diagnosis of PSS, and the mutation types are dominated by point mutations and large deletions.