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Objective To understand the carriage of NDM-1 and other carbapenemases in carbapenem-resistant Acinetobacterbaumannii(CRAB)in Jiangxi area,and provide laboratory basis for the prevention and control of healthcare-associated infection (HAI). Methods Sixty-four strains of CRAB isolated from clinical specimens from 3 tertiary first-class hospitals in Jiangxi area from January 2015 to June 2016 were collected,susceptibility to com-monly used antimicrobial agents were detected with Kirby-Bauer method. Carbapenemases and metalloenzyme in CRAB were screened with modified Hodge test and EDTA-disk synergy test respectively,carbapenems gene was de-tected by polymerase chain reaction (PCR),NDM-1-producing Acinetobacterbaumannii (A. baumannii)were per-formed conjugation test.Results The resistance rates of CRAB to ampicillin/sulbactam,ciprofloxacin,gentamicin, and levofloxacin were up to 95.31% ,98.44% ,90.63% ,and 54.69% respectively. The positive rates of modified Hodge test and EDTA-disk synergy test were 76.56% and 96.88% respectively. PCR amplification result showed that 87.50% (n= 56)of CRAB carried OXA-23 and VIM-1 genes,18.75% (n= 12)carried SIM,3.13% (n= 2)car-ried OXA-24,and 26.56% (n= 17)carried NDM-1 . CRAB carrying NDM-1 gene were all from The First Affilia-ted Hospital of Nanchang University,64.70% (11/17)of which were pandrug-resistant strains. Conjugation test re-sult showed that NDM-1-producing strains could transfer NDM-1 gene to recipient strain Escherichiacoli J53,then acquired resistance to imipenem. Conclusion Antimicrobial resistance rates of clinically isolated CRAB in this area are high,OXA-23 and VIM-1 genes are the main carbapenemase genes,NDM-1 gene positive CRAB is detected, and there may be a clonal spread of NDM-1 gene in hospital,effective measures should be taken as soon as possible to prevent and control the spread of NDM-1 positive CRAB.
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Objective To investigate the carriage and homology of carbapenemase genes of multidrug-resistant Acinetobacterbaumannii (MDRAB)in Wujiang area.Methods A total of 44 non-duplicated MDRAB isolated from patients in 3 general hospitals in Wujiang area from January 2010 to December 2013 were collected. Minimum inhibitory concentrations (MICs)were detected,carbapenemase genes OXA-51,OXA-23,OXA-24,OXA-58, IMP,TEM,SHV,and GES were amplified with polymerase chain reaction(PCR),homology of strains was detec-ted with pulsed-field gel electrophoresis (PFGE).Results 44 MDRAB strains were mainly collected from sputum (93.18% ),mainly distributed in intensive care unit (ICU),department of respiratory diseases,and department of neurosurgery,accounting for 45.45% ,27.27% ,and 13.64% respectively;MDRAB were both sensitive to minocy-cline and polymyxin B,resistance rates to piperacillin,ampicillin/sulbactam,ceftazidime,gentamicin,amikacin, and ciprofloxacin were all 100.00% ,resistance rates to imipenem and meropenem were both 97.73% . 44 MDRAB strains were all detected OXA-51,OXA-23 and TEM genes,12 strains were positive for GES gene,1 strain was positive for OXA-58 and SHV respectively,OXA-24 and IMP genes were not found ;MDRAB were divided into 7 types of G-A,which included 19,3,9,3,1,4,and 5 strains respectively,type A was mainly from two large gen-eral hospitals in Wujiang area (Wujiang First People’s Hospital and Shengze Hospital),type B,D and E strains were not detected in Wujiang First People’s Hospital,type E strain was only 1 isolate and was from Yongding Hos-pital,the other types were sporadically distributed.Conclusion Multidrug resistance of clinically isolated Acineto-bacterbaumannii is serious in Wujiang area,OXA-23 and TEM genes are major causes of multidrug resistance in Acinetobacterbaumannii,the main types are A and C,which present clonal spread.
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Objective To understand the clinical characteristics of Acinetobacter baumannii infections in elderly patients in intensive care unit (ICU)and investigate its drug susceptibility. Methods Bacterial identification was carried out by VITEK?32 automatic micro?analyzer(Bio?Merieux Company of French). Data processing was performed with WHONET5.6 software. Results Totally 259 strains of Acinetobacter baumannii were isolated from 220 infected elderly patients. The detection rate of Acinetobacter baumannii was 71.43%(185 strains),13.13%(34 strains), 6.18%(16 strains )and 9.26%(24 strains)from sputum,drainage fluid,blood and other specimens,respectively . Drug resistance of Acinetobacter baumanniito antibiotics was relatively high. Resistance to tigecycline of Acinetobacterbaumanniistrains was the lowest(0%?23.38%)while the sus?ceptibility was the highest(70.13%?80.85%)in all kinds of antibiotics in this study. Conclusion Acinetobacter baumannii varied in drug resis?tance to different antibiotics. It is necessary to choose susceptible antibiotics for clinical anti?infection treatment on the basis of in?vitro antibiotics sus?ceptibility testing for isolated strains from local regions.
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Objective To investigate the difference in healthcare-associated infection (HAI)status and antimicro-bial resistance of Acinetobacterbaumannii(A.baumannii)isolated from different wards,so as to provide evidence for effective prevention and therapy for HAI caused by A.baumannii.Methods Clinical data of 446 A.baumannii isolates from hospitalized patients between January 2012 and July 2013 were analyzed retrospectively. Results The majority of 446 A.baumanniiisolates were from patients admitted to intensive care unit (ICU,n= 236,52.92% ), followed by departments of respiratory diseases(n= 55,12.33% )and neurosurgery (n= 48,10.76% ),and the strains were mainly isolated from sputum specimens (94.62% ).Antimicrobial susceptibility testing with 13 kinds of commonly used antimicrobial agents showed that antimicrobial resistance of A.baumanniifrom ICU were highest, susceptibility rates were all50% .Conclu-sion The difference in antimicrobial resistance of A.baumanniifrom different wards varied significantly,antimi-crobial resistance of A.baumanniifrom ICU is most serious.
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Objective To explore the effect of combination therapy of aminoglycosides with other antibiotics on reducing the mutant selective window of Acinetobacter baumannii. Methods Three aminoglycoside antibiotics (amikacin, tobramycin, netilmicin)and four frequently used antibiotics against Acinetobacter baumannii in clinical practice (cefoperazone-sulbactam, imipenem-cilastatin,ciprofloxacin and levofloxacin)were studied.The minimum inhibitory concentrations of these antibiotics against Acinetobacter baumannii ATCC1 9606 were determined by E-test.The mutant prevention concentrations of the four antibiotics against Acinetobacter baumannii alone or in combination with aminoglycosides were determined by agar dilution method.The selective index was calculated. The effect of aminoglycosides on mutant selective window of Acinetobacter baumannii was evaluated according to the change of selective index after combination. Results The selective index of cefoperazone-sulbactam,imipenem-cilastatin,ciprofloxacin and levofloxacin against A.baumannii ATCC19606 was 16,>32, 16 and 32.When combined with amikacin,the selective index was 1,2,4 and 4,respectively.When combined with tobramycin,the index was 2,2,8 and 8,respectively.When combined with netilmicin,the index was 2,4,8 and 16, respectively. Conclusions The mutant prevention concentration of the four antibiotics against Acinetobacter baumannii is significantly reduced when combined with any of the three aminoglycosides,which is helpful to decrease the incidence of mutants and control resistant Acinetobacter baumannii. Amikacin-based combination shows the most evident effect on reducing the mutant selective window of Acinetobacterbaumannii.