ABSTRACT
Objective To evaluate the activities of 18 pairs of antimicrobials combinations against non - duplicate clinical isolates of multidrug resistant Acinetobacter baumannii (MDRAB) in vitro.Methods Collect isolates of Acinetobacter baumannii from different patients from October 2009 to May 2010,which were isolated in Clinical Laboratory Center of Beijing Friendship Hospital,Capital Medical University.Use broth microdilution method to detect MIC of mono-antimicrobial,and checkerboard broth microdilution method to detect combinatied MIC,and calculate fractional inhibitory concentration (FIC) index to determine drug combinations effects.When the performance of the same drug combinations conflicted,appropriate strains were selected for screening of drug-resistant mechanisms by polymerase chain reaction( PCR),including efflux pump genes.Results In tests in vitro,rifampicin and polymyxin B,imipenem and gentamicin,cefepime and levofloxacin showed synergy at high proportion,68.1％,45.5％,40.9％,respectively.Minocycline and rifampicin,ampicillin/sulbactam and tobramycin.Ceftazidime and ciprofloxacin showed additive effect at high proportion,81.8％,68.2％,68.2％,respectively.There were several combinations which appeared the opposite effects to tested strains.Strains No.19 corresponding reaction was synergy and No.21,No.26 corresponding reactions were antagonism.The three strains above were selected for screening resistant mechanisms.The difference is that genotypes of adeS were negative in No.19 and positive in No.21 and No.26.Conclusion Rifampicin and polymyxin B combination showed synergy against the MDRAB in vitro,which can be considered as the treatment choice for critical infections caused by MDRAB.Imipenem and gentamicin,cefepime and levofloxacin also showed synergy in vitro,but in some isolates showed antagonism.This phenomenon may be due to the gene adeS activated by certain antibiotics,and the activated adeS drived efflux pump express or overexpress,which made the drugs in bacterial cells pumped out,causing antagonistic effect.The individual differences in strains should be considered when clinic strain apply these two combinations above.
ABSTRACT
OBJECTIVE To analyze multi-drug resistant Acinetobacter baumannii(ABA) outbreak of nosocomial infection in the respiratory intensive care unit(RICU),to explore effective measures for prevention and control.METHODS In RICU on April 3 to 30 2009,patients under mechanical ventilation in the respiratory tract with MDRABA were conductd epidemiological surveys.RESULTS On 27 consecutive days,six cases occurred in mechanical ventilation in patients with lower respiratory tract MDRABA infection,of which 5 patients were cured;6 cases of lower respiratory tract of patients in sputum specimens isolated the same resistance spectrum MDRABA.CONCLUSIONS Medical personnel lack the consciousness of washing their hands.Indoor environment,air disinfection machine lack of supervision in mechanical ventilation patients with lower respiratory tract MDRABA,were the main reasons of infection outbreak.Strict isolation of patients should be strengthened,full implementation of hand-washing compliance,education,conventional screening,early intervention to prevent outbreak of hospital infection.
ABSTRACT
BACKGROUND: The hospital-acquired pneumonia is the most common nosocomial infection. Recently, the Acinetobacter baummannii infections are rapidly increasing, especially the frequency of Multi-drug resistant A. baumannii. Therefore we assessed clinical features and prognosis of patients in the ICU with Multi-drug resistant A. baumannii from the sputum culture using the Clinical Pulmonary Infection Score(CPIS). METHODS: The medical records of 43 patients with Multi-drug resistant A. baumannii from sputum culture who were suspected had clinically pneumonia and admitted to the ICU from January 2000 to July 2002 were retrospectively analyzed. RESULT: 19 patients were CPIS greater than 6 and 24 patients were CPIS less than or equal to 6. Mean age for the former was 71+/-11 years old, and the latter was 61+/-19 years old. The mean APACHE II score on admission and on sputum study was not different between two groups(17.4+/-5.7 vs 18.5+/-6.1, p=0.553, 20+/-6 vs 17+/-8, p=0.078). But the mortality rate was 73.7% for the former, and 16.7% for the latter(p<0.001). CONCLUSION: In ICU patients who had clinically suspected pneumonia with sputum culture positive for Multi-drug resistant A. baumannii, the mortality was significantly higher if CPIS was greater than 6.