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Objective To investigate antimicrobial resistance of Escherichia coli (E.coli )isolated from patients with bloodstream infection,and provide evidence for rational use of antimicrobial agents in clinical practice.Methods BacT/A-lert automated blood culture system and VITEK 2 automated identification system were used for bacterial culture and identi-fication.Antimicrobial susceptibility testing and detection of extended-spectrum β-lactamases (ESBLs)-producing strains were performed by Kirby-Bauer method.Results From 2009 to 2011 ,a total of 235 strains of E.coli were isolated from patients with bloodstream infection,90 (38.30%)of which were ESBLs positive strains.The resistant rates of ESBLs-producing strains to ampicillin,cefotaxime and ceftriaxone were all 100%,but susceptibility rate to imi-penem/cilastatin and meropenem were all 100%,to cefmetazole and amikacin were >90%.The resistant rate of non-ESBLs-producing strains to ampicillin was the highest (70.63%),susceptibility rate to imipenem/cilastatin and meropenem were both 100%,to amikacin,cefotaxime,and cefmetazole were all >95%.The resistant rate of ES-BLs-producing strains was significantly higher than that of the non-ESBLs-producing strains.Ofβ-lactamase inhibi-tor,only susceptibility rate of ESBLs-producing E.coli to cefoperazone/sulbactam was>90%,susceptibility rates to piperacillin/tazobactam and ticarcillin/clavulanate were both<80%.Conclusion Antimicrobial resistant rate of ESBLs-producing strains causing bloodstream infection is high,individualized treatment strategies should be made according to antimicrobial resistance of bacteria causing infection in patients.
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Objective To monitor the constituents and resistant tendency of bacterial pathogens isolated from diarrheal patients in our hospital form 1994 to 2005 to offer the basis for guiding epidemiologic study,vaccination research and clinical treatment. Methods Enteric pathogenic bacteria were cultured and identified to species,group and serotype with biochemical and serologic methods and the susceptibility of bacteria to antimicrobial agents were tested. Results Enteric pathogenic bacteria were isolated predominantly in male patients and mainly in children and youngsters. It reached a peak from July to September every year. Shigella spp.(75.11%) was the most frequendy isolated pathogens and followed by Vibrio spp.(12.7%),Salmonella spp.(6.28%),Aeromonas spp.(4.43%) and Escherichia coli(1.25%).During the period from 1994 to 2005,diarrheal pathogens had a trend of decrease especially Shigella spp.and Salmonella spp.. Of the 6329 isolates of Shigella spp., 75.62% was S. flexneri and S.soanei,S.dysenteriae and S. boydii constituted 23.98%,0.22% and 0.01% respectively.The sensitivity of different species,group or serotype to different antimicrobial agents was not the same.S.flexneri and Aeromonas spp. were highly resistant to most of antibiotics. However, S.sonnei and Vibrio spp.had good susceptibility to antibiotics tested except trimethoprim/sulfamethoxazole and ampicillin. Conclusion There are many species and serotypes of enteric pathogenic bacteria causing infective diarrhea and the distribution changes gradually in Beijing. The resistance rate of enteric pathogenic bacteria to antibiotics is not the same in different species and serotypes.so strict surveillance iS always needed.
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Objective To monitor the distribution and resistance of enteric pathogenic bacteria in Beijing area to offer the data for guiding epidemiologic study and clinical treatment. Methods Enteric pathogenic bacteria were cultured and identified to spicies, group, and serotype with the biochemical and serologic test. Then, the susceptibility of bacterium to antimicrobial agents were tested. Results Enteric pathogenic bacteria infection occurred with male, children, and youth being prominant. It peaked in June and July. Shigellae spp and Vibrio spp were the main pathogenic bacteria of intestinal tract. There presented difference among the sensitive rates of differential spicies, or groups to antimicrobial agents. Conclusions There are many spicies of enteric pathogenic bacteria causing infective diarrhea in Beijing area. Their distributions are different in sex, age and season. The is resistance rate are different needing surveillance.
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Objective To amplify the 16S RNA fragments of 7 clinically isolated strains of Brucella spp. by PCR-RFLP technique, so as to provide experimental basis for the studies on diagnostics, genetics and epidemiology of Brucella spp. Methods According to the gene sequence of ATCC 25840 standard strain in GenBank, special primers for the 16S RNA conservative area in the Brucella spp. were designed. DNA extraction and PCR amplification of the 16S RNA fragments were performed with the 7 isolated strains. PCR products were then sequenced and RFLP analysis was conducted with appropriate restricted enzymes to study the homology and the mutation sites in those strains. Meanwhile, the clinical data of infected patients were retrospectively analyzed to evaluate the relationship between the clinical features and genotypes of Brucella infection. Results The amplified target fragments were about 1500bp in length and consistent with what was expected. The sequencing and homology analysis showed a 98.88% homology and 11 mutation sites among the 7 isolated strains. Four genotypes were identified by RFLP. Retrospective analysis of the clinical data indicated that no obvious relationship existed between the genotypes and the clinical features. Conclusions Amplifying 16S RNA fragments by PCR technique is a feasible method to make an early diagnosis of Brucella infection. The 7 clinically isolated strains are different in genotypes and 16S RNA fragment is a highly conservative fragment in bacterial genome with some mutations. The research provides evidence for the genetics and epidemiology of brucellosis.
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Objective To investigate infection rate and susceptibility to antimicrobial agents of Mycoplasma urealyticum and Mycoplasma hominis in the genitourinary tract, and to provide a reference for clinical diagnosis and therapy. Methods Genitourinary secretions were collected with swabs. They were cultured with the diagnostic kit of Mycoplasma (Biomerieux Company) to detect M. urealyticum and M. hominis. Meanwhile the susceptibility of Mycoplasma against 9 antimicrobial agents was tested with the same kit. According to the manual of the kit, the results were read. The data were statistically analyzed with WHONET5.1 and SPSS. Results A total of 1 008 samples were collected, and the positive rate was 77.5%. Among 781 positive cases of Mycoplasma, 572 were M. urealyticum(56.0%), 40 were M. hominis (4.0%), and 169 were M. urealyticum combined with M. hominis (16.7%). The susceptibility rate of M. urealyticum to Doxycycline, Josamycin, Ofloxacin, Erythromycin, Tetracycline, Ciprofloxacin, Azithromycin, Clamycin and Pristinamycin was 89.3%, 95.1%, 17.5%, 64.3%, 84.1%, 14.8%, 77.8%, 90.8% and 96.5%, respectively. The susceptibility rate of M. hominis to the above drugs was 86.0%, 78.9%, 23.2%, 0, 73.2%, 57.1%, 0, 7.7% and 83.9%, respectively. The resistant rate of Mycoplasma to Azithromycin and Clamycin in 2004 was higher than that during the period of 2000 to 2003(P