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Objective To investigate the resistance profile of Klebsiella pneumoniae isolates in Huashan Hospital, Fudan University. Methods The MICs of fluoroquinolones were determined by agar dilution method against 112 clinical strains of K. pneumoniae. Multilocus sequence typing (MLST) were applied to 48 K. pneumoniae strains. The characteristic sequence type (ST) associated with antibiotic resistance was identified by PCR. Results Lower percentage (＜40％) of K. pneumoniae strains were susceptible to fluoroquinolones. Majority (86.2％) of ciprofloxacin non-susceptible K. pneumoniae strains belonged to CC1 (ST11), ST494 or CC4 (ST15 and ST655), indicating the potential of clonal dissemination. ST494 (18.8％) was the second commonest sequence type, next only to ST11. ST494 strains harbored the genes encoding beta-lactamases, oqxAB, qnrD, aac-(6')-lb-cr and armA and had a single point mutation in gyrA. Therefore, ST494 strains were highly resistant to cephalosporins, fluoroquinolones and aminoglycosides and 22％ of the strains were resistant to carbapenems. However, all the ST494 strains were susceptible to tigecycline and tetracycline. Conclusions ST11 and ST494 are the commonest STs of K. pneumoniae conferring multidrug resistance in this hospital. These STs may contribute to the high resistance rates of K. pneumoniae to fluoroquinolones. The susceptibility of ST494 strains to tigecycline and tetracycline allows us to consider the promising potential of such drugs in managing K. pneumoniae infections.
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Objective To investigate the clinical characteristics of the infections caused by carbapenem-resistant Pseudomonas aeruginosa (CRPA) for better prevention and treatment of CRPA infections. Methods A retrospective study was conducted to compare the features of CRPA infections (n=85) and carbapenem-susceptible P. aeruginosa (CSPA) infections (n=94) treated in Huashan Hospital from January 1, 2013 to December 31, 2013. Results? The?proportion?of?CRPA?infections?was?significantly?higher?than CSPA in Neurosurgery (40.0% versus 16.0%) and Intensive Care Unit (22.4%, 9.6%). Traumatic brain injury (30.6%) and vascular accidents (21.2%) were the main underlying diseases in CRPA patients, which was higher than in CSPA patients (11.7%and?8.5%,?respectively).?CRPA?infection?was?associated?with?significantly?higher?incidence?of?fever,?altered?mental?status,?and?severe hypoproteinemia than CSPA infection. Multiple bacterial infection was found in more CRPA patients (45.9%, 39/85) than in CSPA patients (24.5%, 23/94). Fewer CRPA patients showed positive treatment response (44.7%, 38/85) than CSPA patients (78.7%, 74/94). CRPA was associated with significantly more cases of disease progression (55.3%, 47/85) and more deaths (16.5%, 14/85) than CSPA (21.3% and 1.1%, respectively). Logistic regression analysis indicated that stay in Department of Neurosurgery, prior carbapenem use, peripherally inserted central catheter, nasal feeding, and mechanical ventilation were the risk factors for CRPA infection. Conclusions No specific clinical manifestation is associated with CRPA infection, which poses a therapeutic challenge and results in unfavorable prognosis. Rational use of antibacterial agents and appropriate supporting treatments are essential for control of CRPA in Huashan Hospital.
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Objective To investigate the antibiotic resistance pattern and molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa.Methods The antimicrobial susceptibility was measured by agar dilution method for the 104 strains of carbapenem-resistant P.aeruginosa (CRPA) collected from Huashan Hospital.The homology between these strains was evaluated by pulsed field gel electrophoresis (PFGE).Results Of thel04 CRPA strains,85.6％ were resistant to meropenem and 98.1％ to imipenem.These strains also showed various percentages of resistance to amikacin (18.3％),gentamicin (40.4％),ceftazidime (26.9％),cefepime (21.2％),ciprofloxacin (44.2％),levofloxacin (50.0％),piperacillin-tazobactam (19.2％),cefoperazone-sulbactam (26.9％),ticarcillin-clavulanic acid (52.9％),aztreonam (26.9％),and colistin (5.8％).PFGE analysis showed that these strains were divided into 48 types,belonging to 9 clones.Only 3 strains were non-typeable.Clone A was the primary epidemic strain (41.6％,42/101),which was mainly isolated from Neurosurgery,Geriatrics and General Ward.Clone B accounted for 5.9％ (6/101) of the strains.Conclusions Multiple clones of carbapenem resistant Pseudomonas aeruginosa were prevalent in Huashan hospital.Effective infection control approaches should be adopted to prevent the development and the further spreading of antimicrobial resistance.