Objective To explore antimicrobial resistance of lower respiratory tract infection with Stenotrophomonas maltophilia. Methods The ability of Stenotmphomonas maltophilia, isolated from clinical samples in patients with lower respiratory tract infections, to resist 14 antibiotics was measured by VITEK60 GNS from Jan.2001 - Jan.2007.Results During Jan.2001 - Jan.2007, there were133 Stenotrophomonas maltophilia strains isolated from lower respiratory tract specimens. The sensitivity of Stenotrophomonas maltophilia to the antibiotic Penicillin was the poorest. The sensitivity of Stenotrophomonas maltophilia to Cefepime was the highest as was also the case with approximately 88.0% of the Cephalosporins. However, trimethopsulfamethoxazole seemed to produce the greatest sensitivity (approximately 92.5% ) . Conclusion Stenotrophomonas maltophilia, isolated from the lower respiratory tract, is known to be highly resistance to multiple antibiotics. Trimethoprim-sulfamethoxazolemay may be the best antibiotic choice for Stenotrophomonas rrraltophilia infections. These results also indicate that Clinicans should choose antibiotics according to results attained through an antibiotic susceptibility test.

Objective The present study was designed to establish a model of mycoplasma pneumonia of swine ( MPS) by artificial challenge. Methods Mycoplasma hyopneumoniae Is strain was isolated and identified by biochemical and serological assays. MPS negative pigs were inoculated with 2ml of Mycoplasma hyopneumoruae is strain culture by direct lung inoculation. The pigs were observed daily for 15 to 20 days post-inoculation for clinical symptoms and pathological changes. Infected tissues with live Mycoplasma hyopneumoniae virulent strain were lyophilized and used as the master seed for animal challenge. Artificial challenge was performed by delivering 5ml of lyophilized pathological tissues, intratracheally,into 15 Meishan pigs. The lyophilized pathological tissues used for challenge were diluted by 10^-2,10^-3, 10^-4 fold in KM₂ culture medium, and pigs in the control group were inoculated with 5 ml KM₂ culture medium. Clinical symptoms, pathological changes and lung X-ray results were observed twenty-five days post challenge. Results Typical clinical symptoms and pathological changes associated with MPS were observed in all pigs intratracheally inoculated with lyophilized pathological tissues that were diluted in KM₂ culture medium. Therefore, 5 ml of the 10^-4 dilution of lyophilized pathological tissues with Mycoplasma hyopneumoniae is strain was the minimum dose required to induce MPS in an artificial challenge model. ConeJusion The artificial challenge model of MPS coWd be established by intratracheally inoculation of 5m1 of a 1o-2 dilution of lyophilized pathological tissues infected with the Myooplasma hyopneumoniae is strain.