Study On Bacterial Resistance Monitoring Of Hospital Infection And Mainly MDR Resistance Molecular Level

?Objective?To investigate the distribution of pathogens and antibiotics resistance of clinical isolates from various specimens in Gansu provincial hospital from 2008 to 2012.T o get information about bacterial resistance and its epidemic trend for clinical refere nce in the use of antibacterial agents.?Methods?Clinical infectious specimens from wards of hospital were involved in this progr am such as blood,sputum,bronchoalveolar lavage fluid,urine,bile,faecal,wound,thr oat swap,erebrospinal fluid and etc.According to the specimen type and traditional isolating methods of strains,ino culation aerobic and anaerobic blood culture bottles for blood culture;The other sa mples were inoculated on blood plate,chocolate agar plate,MacConkeyAgar plate b y the streak plate method in accordance with the "third edition of clinical laboratory operating procedures".Then put the plates to 35? or 35? common or CO2 envir onment incubation for 18-24 h.The suspected colonies were picked to smear and Gram staining,and observation of bacterial morphology under the microscope.Base d on th Gram staining characteristics and morphological characteristics of pathogen,The pathgen were identified by traditional manual method,automation instrument(France,the United States Vitek32 microbial analyzer MicroScan-Auto-4 semi-autom atic bacteria analyzer)and API bacterial identification system(Bio-Merieux);the agar diffusion method recommended by WHO(Kirby-Bauer method,K-B)for drug sensit ivity test.Antibacterials including penicillin,oxacillin,ampicillin,gentamicin,amikacin,ciprofloxacin,levofloxacin,cefazolin,cefuroxime,cefotaxime,ceftazidime,imipenem,polymyxin,erythromycin,tetracycline.Double disc synergy ESBLS detection metho d for the detection of Escherichia coli,Klebsiella,Proteus mirabilis;screening for methicillin-resistant Staphylococcus aureus strains by cefoxitin method;detection of p enicillin-resistant Streptococcus pneumoniae strains by E-test method;the method o f detection of vancomycin vancomycin resistant enterococci.The result of bacterial drug resistance were interpreted by the latest edition of the American Clinical Instit ute of Microbiology(Clinical and Laboratory Standards Institute,CLSI)guidline.The data were analyzed by software WHONET 5.6.Results(?)Distrubition of PathogensA total of 10430 clinical isolates were collected from January 2008 to 2012,of which gram positive cocci and gram negative rods accounted for 27.8 % and 72.2% respectively.The top 10 pathogens were Escherichia coli,Klebsiella pneumoniae,Staphylococ cus aureus,Enterobacter cloacae,Acinetobacter baumanii,Pseudomonas aeruginosa,Staphylococcus epidermidis,Enteroccus faecalis,Enteroccus faecium and Acinetobact er lwoffi.The top10 gram positive pathogens were Staphylococcus aureus,Staphylococcu s epidermidis,Enteroccus faecalis,Enteroccus faecium,Streptoccus agalactiae,Stre ptoccus pneumoniae,Bacillus cerenus,Streptoccus viridans,Enteroccus raffinosus a nd Staphylococcus haemolyticus.The top10 gram negative pathogens were Escherichia coli,Klebsiellapneumonia e,Enterobacter cloacae,Acinetobacter baumanii,Pseudomonas aeruginosa,Acinetob acter lwoffi,Haemophilus parainfluenzae,Stenotrophomonas maltophilia,Haemophilus influenzae and Citrobacter freundii.The susceptibility testing results showed that Methicillin resistant strains in S.au reus(MRSA)and coagulase negative Staphylococcus(MRCNS)accounted for an a verage of 55.0 % and 70.7%% respectively.The resistance rates strains to ?-lacta ms and other antimicrobial agents were much higher than those of MS strains.However,No staphylococcal strains was resistant to vancomycin,teicoplanin and lin ezolid.The resistance of E.faecalis strains to most of the drugs tested was much l ower than those of E.faecium.No strains of both E.faecium and E.faecalis were fo und resistant to vancomycin,teicoplanin or linezolid.No PRSP strains were found.The top5 pathogens in different wards:Department of Respiration: Escherichia coli,Klebsiella pneumoniae,Staphylococc us aureus,Enterobacter cloacae,Acinetobacter baumanii.Department of Hematology: Escherichia coli,Klebsiella pneumoniae,Pseudomon as aeruginosa,Staphylococcus epidermidis,Staphylococcus aureus.Department of Urinary surgery: Escherichia coli,E.faecalis,E.faecium,Enterob acter cloacae,Proteus mirabilis.Department of Medical oncology: Escherichia coli,Klebsiella pneumoniae,Entero coccus faecium,Pseudomonas aeruginosa,Enterobacter cloacae.ICU: Acinetobacter baumanii,Klebsiella pneumoniae,Escherichia coli,Staphylo coccus aureus,Pseudomonas aeruginosa.Department of Medical neurology: Escherichia coli,Klebsiella pneumoniae,Staph ylococcus aureus,Enterobacter cloacae,Acinetobacter baumanii.Department of Medical neurosurgery: Acinetobacter baumanii,Klebsiella pneum onia,Escherichia coli,Staphylococcus aureus,Pseudomonas aeruginosa.The top5 pathogens in different specimens:Blood: Staphylococcus epidermidis,Escherichia coli,Enterobacter cloacae,E.fae cium,Klebsiella oxytoca.Sputum or Bronchoalveolar lavage fluid: Escherichia coli,Klebsiella pneumoniae,Staphylococcus aureus,Enterobacter cloacae,Acinetobacter baumanii.Urine: Escherichia coli,E.faecalis,E.faecium,Enterobacter cloacae,Proteus mi rabilis.Bile: Escherichia coli,Klebsiella pneumoniae,Enterobacter cloacae,E.faecalis,E.faeciumWound: Staphylococcus aureus,Escherichia coli,Enterobacter cloacae,Staphyl ococcus epidermidis,E.faecalis.(?)Drug resistant spectrum of pathgensStaphylococcus is one of the important bacteria causing nosocomial infection a mong Gram-positive cocci,the methicillin-resistant Staphylococcus aureus(MRSA)a nd coagulase negative staphylococcus(MRCONS),vancomycin-resistant enterococci(VRE),penicillin resistant Streptococcus pneumoniae(PRSP)were a key monitorin g pathgens in Gram-positive bacteria.Staphylococcus aureus and coagulase negati ve staphylococcus,methicillin resistant strains(MRSA and MRCNS)were for an ave rage of 55% and 70.7%,which resistant to ?-lactam antibiotics and other antibact erial drugs was significantly higher than that of MSS,Enterococcus faecium drug re sistance rate is higher than the Enterococcus faecalis,Streptococcus pneumoniae s eparation rate increased,not penicillin resistant Streptococcus pneumoniae(PRSP),and no vancomycin,teicoplanin and linezolid resistant strains between 5 years.Extended-spectrum beta-lactamases(ESBLS)of Escherichia coli,Klebsiella spp.and Proteus mirabilis,multidrug resistant Acinetobacter,Pseudomonas aeruginosa were key monitoring pathgens among Gram-negative bacteria.Escherichia coli,Kle bsiella(Klebsiella pneumoniae and Klebsiella oxytoca),Proteus mirabilis producing ESBLS percentage were 65.7%,64.8%,73.3%,71.2% and 70.3%;38.8%,30.5%,30.8%,r 31.2%%,30.8%;38.8%;30.5%;30.8%;20.1%;21.2% respectively from 2008 to 2012.ESBLS strains to antimicrobial resistance rates are higher than non ESBLS.En terobacteriaceae remain sensitive to Carbapenems(<2%)past 5 years,the averag e resistance of Pseudomonas aeruginosa to imipenem,meropenem rates were 9.2% and 8.9%.Acinetobacter to the average of two resistance rates were 29.1%,28.2%.ConclusionsBacterial resistance is on the rise,especially the incidence of MRSA,MRCNS and MDR or pan-resistant(PDR)gram negative organisms,which has become a m ajor challenge to infectious disease treatment.It is mandatory for each medical wor kers to take effective measures to control the dissemination and outbreak of infecti ons caused by MDR organisms.