Objective To understand and analysis of the pathogens distribution and drug resistance of nosocomial infection in children′s hospital,so as to provide reliable scientific basis for the prevention and control of hospital infection.Methods 396 cases of upper respiratory tract specimens were collected from pediatric patients with nosocomial infection.These specimens were detected by sputum specimens conventional methods of microorganism cultivation,and K-B method was used to determine the bacteria sensi-tivities to clinical common drug.Results There were 225 cases of specimens were pathogen positive among all the 396 specimens, and 234 strains of bacteria were isolated in all.The positive isolated rate was 56.8%(225/396).Among the 234 isolated strains, Gram negative bacteria accounted for 72.6%(170/234),and Klebsiella occupied the first place[49.4%(84/170)].Gram positive bacteria accounted for 23.5%(55/234),and Staphylococcus had the highest isolated rate in Gram positive bacteria[58.2% (32/55)].In all the 9 kinds of clinical common antimicrobial agents,imipenem had high drug sensitivity to the 234 isolated strains,and the aminoglycosides came next.Conclusion It is necessary for the pediatric patients with nosocomial infection to collect upper re-spiratory tract specimens for bacteriologic studies and drug sensitivity tests.

Objective To investigate the peri-nasopharyngeal invasion patterns of nasopharyngeal carcinoma (NPC) on MRI and its relationship with tumor staging. Methods One thousand five hundred and seventy-three patients with newly diagnosed NPC which were histo-pathologically proved were retrospectively studied. The MRI manifestations and invasion patterns of the NPCs were elevated according to the 2008 Tstaging system of NPC. Z test was used to analyze the rate of adjacent structures invasion in NPCs. Results The structures invaded by NPCs included pharyngobasilar fascia in 1299 cases (82. 58% ); parapharyngeal space, 1090 ( 69. 29% ); nasal cavities, 304 ( 19. 33% ); oropharynx, 49 ( 3. 12% ); carotid space,514(32. 68% ); medial pterygoid muscle, 661 (42. 02% ); lateral pterygoid muscle, 210( 13. 35% ); skull base bones, 943(59. 95% ); cranial nerves, 630(40. 05% ) and paranasal sinuses, 242 ( 15.38% ). The T-stage distribution was T1, 242 cases ( 15.38% ); T2, 288 ( 18. 31% ); T3, 410 (26. 06% ) and T4,633 (40. 24% ). Among the cases with nasal cavities invasion, 90. 46% (275/304)showed the involvement of the structures seen in T3 or T4 stage, which was found in all cases with oropharynx invasion. In addition,69. 14% (457/661) of cases with medial pterygoid muscle invasion and 92. 15% (223/242) of cases with paranasal sinuses invasion showed the involvement of structures seen in T4 stage. As for the invasion patterns of NPC, the lateral invasion of pharyngobasilar fascia was more frequent than upward invasion of skull base (Z = 14. 025, P ＜ 0. 01 ) and downward invasion of oropharynx ( Z = 45.032, P ＜ 0. 01 ), and the downward invasion of oropharynx was less frequent than upward invasion of skull base ( Z = 34. 301, P ＜ 0. 01 ) and forward invasion of nasal cavities ( Z = 14. 404, P ＜ 0. 01 ). Conclusion NPC has a predilection of lateral invasion rather than upward and downward invasion, and its upward and forward invasion are more common than downward invasion.