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Objective:To monitor the susceptibility of common used antimicrobial agents against nosocomial Gram-negative bacilli in 2018 across China.Methods:Prospective collection of Gram-negative bacilli from 13 teaching hospitals nationwide from January to December 2018. The minimal inhibitory concentration (MICs) of antibiotics such as meropenem was determined by agar dilution methods and broth microdilution methods. Interpretation of results using the Clinical and Laboratory Standards Institute(CLSI) 2019 M100S (29th Edition) standard. Data were analyzed by using WHONET-5.6 software.Results:A total of 1 214 non-repetitive Gram-negative bacilli were collected, accounting for 96.7% (1 174/1 214) of blood and sterile body fluid samples. The activity of antimicrobial agents against 871 strains of Enterobacteriaceae was as follows in descending order of susceptible rate: amikacin (93.2%, 812/871), meropenem (92.0%, 801/871), ertapenem (88.9%, 774/871), imipenem (88.4%, 770/871), piperacillin-tazobactam (84.0%, 732/871), cefoperazone-sulbactam (83.1%, 724/871), cefepime (71.4%, 622/871), minocyline (68.9%, 600/871), ceftazidime (66.9%, 583/871), levofloxacin (54.4%, 474/871).The resistance rates of Escherichia coli to the third generation cephalosporins were 61.5% (155/252) (ceftriaxone) and 60.7% (153/252) (cefotaxime), respectively. The resistance rates of Klebsiella pneumoniae to the third generation cephalosporins were 56.6% (126/222) (ceftriaxone) and 57.9% (129/222) (cefotaxime), respectively. The incidence of extended-spectrum β lactamase (ESBLs) positive E. coli and K. pneumoniae was 50.2% (127/252) and 18.2% (40/222), respectively. Over 95% of all the ESBLs positive strains were susceptible to imipenem and meropenem. The incidence of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae was 2.8% (7/252) and 20.4% (45/222), respectively. For Enterobacter cloacae, Klebsiella aerogenes, Citrobacter freundii, the most susceptible agent were tigecycline (96.3%-100%), followed by amikacin (94.9%-97.1%), meropenem (89.8%-96.6%)and imipenem (89.8%-94.9%).The susceptibility of Proteus mirabilis, Morganella morganii and Serratia marcescens to meropenem and amikacin was over 90%.A total of 67 strains of carbapenems resistant enterobacteriaceae(CRE) were detected. Modified carbapenem inactivation method showed, 45 strains were serine carbapenemase and 20 were metalloenzymes. The susceptibility of Pseudomonas aeruginosa to meropenem and imipenem were 73.2% (112/153) and 66.0% (101/153), respectively. Acinobacter baumannii has the highest sensitivity to colistin (100%, 163/163), followed by tigecycline (87.1%, 142/163).Compared with other sources of infection, specimens of bloodstream infections were less resistant to Klebsiella pneumoniae (17.6%, 27/153 vs 21.7%, 15/69) and Acinetobacter baumannii (68.3%, 71/104 vs 71.2%, 42/59). Escherichia coli (2.5%,4/198 vs 0%,0/54) and Pseudomonas aeruginosa (37%, 33/89 vs 18.8%, 12/64) have a high proportion of carbapenem resistance. Conclusions:Carbapenems still maintain high antibacterial activity against Enterobacteriaceae bacteria, especially strains producing only ESBLs. Carbapenem-resistant Klebsiella pneumoniae should be given sufficient attention. Carbapenemase is the most important drug resistance mechanism of carbapenem-resistant Enterobacteriaceae in China.
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Objective:To investigate the epidemiological characteristics of community acquired pyogenic liver abscess (CA-PLA) as a reference for its early identification, early diagnosis and rational antibacterial treatment.Methods:A single center retrospective study was carried out in patients with CA-PLA hospitalized in First Hospital of China Medical University from January 2011 to December 2017.The symptoms, signs and treatment results were concluded. The underlying diseases and onset symptoms of the cases were grouped by year, and the change trend of the disease characteristics was analyzed. The etiology results were grouped according to whether the patients had underlying diseases of biliary tract, and the etiology characteristics were analyzed. Statistical analysis was performed by using chi-square test.Results:A total of 1 063 CA-PLA cases were included in this study. The analysis on underlying diseases grouped by year showed that the number of patients admitted to the hospital increased annually, and the percentage of patients with underlying hepatobiliary diseases decreased from 17.3% (19/110) in 2011 to 7.3% (14/191) in 2017, the difference was statistically significant ( χ2=13.648, P=0.034), while that of patients with diabetes mellitus kept high at 31.6% to 46.5% in the past seven years without increasing trend. There were 274 patients (25.8%) with extrahepatic manifestations. Totally 445 cases were microbiologically diagnosed, among which single Klebsiella pneumoniae infection was found in 371 cases (83.4%). Klebsiella pneumoniae was the leading pathogen in patients without underlying hepatobiliary diseases (91.6%, 362/395), in contrast to 18.0%(9/50) in patients with underlying hepatobiliary diseases. The other pathogens were Escherichia Coli (32.0%, 16/50) and mixed infection (18.0%, 9/50). The susceptibility rate to second generation and above cephalosporins of clinically defined hypervirulent Klebsiella pneumoniae was ≥97.5%, and that to carbapenems was 100.0%. Most patients had good prognosis, and 1 049 cases were cure or improvement discharged, six cases left hospital voluntarily, and eight cases died. Conclusions:Most of the CA-PLA patients have no underlying hepatobiliary diseases, and more than half of patients have no history of diabetes mellitus. Most of the pathogens are Klebsiella pneumoniae, which are relatively sensitive to antimicrobial agents.
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Objective To describe the clinical characteristics of hypervirulent Klebsiella pneumoniae (hvKP) infection.To analyze the antibiotic susceptibility of hvKP to provide the empiric antibiotic options.To investigate capsule serotype and sequence type (ST) of hvKP and their correlation with clinical profiles.Methods hvKP was defined as bacteria isolated from patients with community-acquired pyogenic liver abscess (CA-PLA) with co-infection sites outside liver or a bloodstream infection in a host without underlying biliary tract diseases.Patients with CA-PLA hospitalized in the First Hospital of China Medical University were retrospectively analyzed from January 2011 to December 2017.Antibiotic susceptibility was detected by automatic bacterial identification and antibiotic susceptibility analysis system in vitro.Polymerase chain reaction method and gene sequencing were used to detect the main capsule serotype and ST.Results A total of 140 cases with hvKP infection were enrolled.The co-infections outside liver abscess included 98 bloodstream infections,53 pneumonia,11 perianal abscess,10 urinary system infections,3 subphrenic abscess,3 endophthalmitis,2 spleen abscess,and other miscellaneous infections including 1 peritonitis,1 skin and soft tissue infection,1 myelitis,1 colitis,1 psoas major abscess and 1 myocardial abscess.Among the 140 cases,106 presented with single co-infection site,32 with 2 sites,and 2 with 3 sites.HvKP manifested high antibiotic susceptibility up to 80％ for most commonly used antibiotics.Capsule serotyping of 4,3 revived isolates indicated that K1 serotype accounted for 53.49％ (23/43),K2 34.88 (15/43),K54 2.33％ (1/43),K57 2.33％ (1/43),and other serotypes 6.98％(3/43).There was no significant distribution among K1,K2,K54,and K57 of hvKP capsule serotypes in patients with or without diabetes mellitus (P＞0.05).Multilocus sequence typing (MLST) suggested that ST23 and ST65 were predominant accounting for 39.53％ (17/4.3) and 25.58％ (11/4.3) respectively.No serotype or ST predominance was seen in any of the clinical infections.Conclusion HvKP is related to a wide spectrum of infectious diseases,including multiple extrahepatic sites and bloodstream infections besides CA-PLA with high antibiotic susceptibility.K1 and K2 are the predominant capsule serotypes,and ST 23 and ST65 are the predominant sequence types.
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Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.
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Objective To investigate the spectrum and antimicrobial resistance of major pathogens causing nosocomial infections in China, 2016. Methods Non-duplicated nosocomial cases as well as pathogens causing bloodstream infections ( BSI) , hospital-acquired pneumonia ( HAP) and intra-abdominal infections ( IAI ) from 12 teaching hospitals across China were collected. The minimum inhibitory concentrations (MICs) of important clinical common strains were determined by agar dilution method or broth microdilution method. The CLSI M100-S27 criteria was used for interpretation. Data were analyzed by using WHONET-5. 6 software. Results A total of 2060 cases were collected, including 894 cases from BSI, 630 cases from HAP and 536 cases from IAI. The MICs of 1896 important clinical common strains were determined. Escherichia coli and Klebsiella pneumoniae were the most prevalent pathogens causing BSI and IAI, while Acinetobacter baumanii and Pseudomonas aeruginosa were dominated in HAP. All Staphylococcus aureus were susceptible to tigecycline, linezolid, daptomycin and glycopeptides. Methicillin-resistant S. aureus accounted for 44. 4％ ( 75/169 ) of all the S. aureus. The rate of methicillin-resistant coagulase-negative staphylococci was 80. 9％ ( 72/89 ) . No Enterococcus strains were found resistant to tigecycline, linezolid or daptomycin. Vacomycin resistant enterococcus was found in Enterococcus faecium, accounting for 1. 8％ ( 2/111 ) of all E. faecium strains. Tigecycline, meropenem, amikacin, imipenem, and polymyxin B exhibited high potency against Enterobacteriaceae and the susceptibility rates were 96. 6％(865/895), 94. 3％ (859/911), 94. 2％ (858/911), 94. 1％ (857/911), and 91. 6％ (820/895), respectively. The prevalence of extended-spectrum β-lactamase was 58. 4％ ( 263/450 ) in E. coli and 28. 6％ ( 84/294 ) in K. pneumonia. The rate of carbapenem resistant K. pneumonia and E. coli was 15. 3％ ( 45/294 ) and 1. 8％ ( 8/450 ) , respectively. The percentage of polymyxin B resistant K. pneumonia and E. coli was 4. 1％ ( 12/294 ) and 4. 4％ ( 20/450 ) , respectively. The rate of tigecycline resistant K. pneumonia and E. coli was 2. 4％ ( 7/294 ) and 0. 2％ ( 1/450 ) , respectively. A. baumanii showed low susceptibility to the antimicrobial agents except tigecycline ( 91. 4％, 235/257 ) and polymyxin B (100％, 257/257). The rate of carbapenem resistant A. baumanii was 80. 5％ (207/257). The rate of carbapenem resistant P. aeruginosa was 31. 7％ ( 59/186 ) . Polymyxin B and amikacin demonstrated high antibacterial activity against P. aeruginosa with susceptility rate of 100％ ( 186/186 ) and 90. 9％ ( 169/186), respectively. Conclusions Nosocomial pathogens showed high susceptibilities against tigecycline and polymyxin B. Antimicrobial resistance in A. baumannii is a serious problem. The prevalence of carbapenem-resistant Enterobacteriaceae and polymyxin B resistant Enterobacteriaceae has increased, which should be monitored continuously in China.
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Objective To retrospectively analyze the clinical distribution and changes in antimicrobial resistance profiles of Staphylococcus aureus (S. aureus). Methods We collected clinical specimens of S. aureus from The First Hospital of China Medical University. The Vitek-2 and BD Phoenix 100 were performed for bacterial identification and drug sensitivity tests,and WHONET 5.6 was used to analyze the data. Results From 2007 to 2016,there were 3 377 unrepeatable strains of S. aureus,including 1 705 that were methicillin resistant S. aureus (MRSA). The isolation rate of S. aureus was 9.4 ％ and of these,50.5 ％ were MRSA. There were 776 S. aureus specimens from outpatients or the emergency department,including 16.8 ％ MRSA,and 2 011 S. aureus from inpatient departments,including 60.2 ％ MRSA. The main sources of specimens were sputum (41.8 ％),pus (17.9 ％),and body secretions (17.5 ％). The average resistance rates of MRSA for erythromycin,ofloxacin,ciprofloxacin,gentamycin,and tetracycline were higher than 75.0 ％. The average resistance rate of methicillin sensitive S. aureus (MSSA) for erythromycin was up to 76.8 ％,and for tetracycline,gentamycin,ciprofloxacin,and ofloxacin,were less than 25.0 ％. In 10 years,the average resistance rates of MRSA and MSSA for 11 kinds of common antibiotics had no obvious change. Conclusion The constituent rate of MRSA was high in The First Hospital of China Medical University,especially from the areas that were not sterile,suggesting that clinicians should pay attention to the identification of infection and sources for MRSA,which were from such areas. Hospital infection control should be focused on at the same time,in order to reduce the incidence of MRSA.
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To dynamically investigate the distribution and antimicrobial resistance profiles of bacteremia pathogens isolated from different regions in China in 2011, 2013 and 2016. Non-repetitive isolates from nosocomial bloodstream infections were retrospectively collected and detected for antimicrobial susceptibility tests (AST) by agar dilution or microbroth dilution methods. Whonet 5.6 was used to analyze the AST data. Among 2 248 isolates, 1 657 (73.7%) were Gram-negative bacilli and 591 (26.3%) were Gram-positive cocci. The top five bacteremia pathogens were as follows, Escherichia coli (32.6%, 733/2 248), Klebsiella pneumoniae (14.5%, 327/2 248), Staphylococcus aureus (10.0%, 225/2 248), Acinetobacter baumannii (8.7%, 196/2 248) and Pseudomonas aeruginosa (6.2%, 140/2 248). Colistin (96.5%, 1 525/1 581, excluding innate resistant organisms), tigecycline (95.6%, 1 375/1 438, excluding innate resistant organisms), ceftazidine/clavulanate acid (89.2%, 1 112 /1 246), amikacin (86.4%, 1 382/1 599) and meropenem (85.7%, 1 376/1 605) showed relatively high susceptibility against Gram-negative bacilli. While tigecycline, teicoplanin and daptomycin (the susceptibility rates were 100.0%), vancomycin and linezolid (the susceptibility rates were 99.7%) demonstrated high susceptibility against Gram-positive cocci. The prevalence of extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriaceae were 50.6% (206/407), 49.8% (136/273) and 38.9% (167/429) in 2011, 2013 and 2016 respectively; carbapenem-non-susceptible Enterobacteriaceae were 2.2% (9/408), 4.0% (16/402) and 3.9% (17/439) in 2011, 2013 and 2016 respectively; The prevalence of multidrug-resistant A. baumannii (MDRA) was 76.4% (55/72) in 2011, 82.7% (43/52) in 2013 and 87.5% (63/72) in 2016, respectively. The prevalence of multidrug-resistant P. aeruginosa (MDRP) was 9.8% (5/51) in 2011, 20.0% (7/35) in 2013 and 13.0% (7/54) in 2016, respectively. The prevalence of methicillin-resistant S. aureus (MRSA) was 51.9% (41/79) in 2011, 29.7% (19/64) in 2013 and 31.7% (26/82) in 2016, respectively. The prevalence of high level gentamicin resistance (HLGR) of Enterococcus faecium and Enterococcus faecalis were 43.2% (48/111) and 40.9% (27/66), respectively. The predominant organism of carbapenem-non-susceptible Enterobacteriaceae was K. pneumoniae with its proportion of 57.1% (24/42). Among 30 tigecycline-non-susceptible Enterobacteriaceae, K. pneumoniae was the most popular organism with 76.7% (23/30). Among 39 colistin-resistant Enterobacteriaceae, E. coli, Enterobacter cloacae and K. pneumoniae were constituted with the percent of 43.6 (17/39), 35.9 (14/39) and 15.4 (6/39), respectively. The Gram-negative bacilli (E. coli and K. pneumoniae were the major organisms) were the major pathogens of nosocomial bacteremia, to which tigecycline, colistin and carbapenems kept with highly in vitro susceptibility. Whereas, among the Gram-positive cocci, S. aureus was the top 1 isolated organism, followed by E. faecium, to which tigecycline, daptomycin, linezolid, vancomycin and teicoplanin kept with highly in vitro susceptibility. Isolation of colistin-resistant Enterobacteriaceae, tigecycline-non-susceptible Enterobacteriaceae, linezolid- or vancomycin-non-susceptible Gram-positive cocci suggests more attention should be paid to these resistant organisms and dynamic surveillance was essential.
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Objective To investigate antimicrobial resistance among nosocomial gram-negative bacilli in 2016 across China.Methods About 1 394 consecutive and non-repetitive gram-negative bacilli were isolated from 14 teaching hospitals from March to August in 2016 across China.All of these isolates were sent to the central laboratory for reidentification and susceptibility testing.The minimal inhibitory concentration(MICs)of meropenem and other antibacterial agents were determined by agar dilution method.The data were analyzed by using WHONET-5.6 software.Results The activity of antimicrobial agents against Enterobacteriaceae was as follows in descending order of susceptible rate: meropenem (95.2%,891/936), amikacin (94.6%,885/936), ertapenem (92.1%,862/936), piperacillin/tazobactam (88.1%,825/936), imipenem (88.0%,823/936), cefoperazone-sulbactam (83.1%,778/936), cefepime (72.2%,676/936), cefiazidime (72.2%,676/936), levofloxacin(68.8%,644/936), ciprofloxacin (63.2%,592/936), minocyline (62.9%,589/936), cefiriaxone (54.9%,514/936), cefotaxime (54.0%,505/936), cefoxitin (44.3%,415/936).The sensitivities of E.coli to carbapenems, amikacin, piperacillin-tazobactam, polymyxin B and cefoperazone-sulbactam were over 80%.The more sensitive antibiotic to Klebsiella pneumoniae was polymyxin B (99.0%), followed by amikacin (84.9%), meropenem (84.4%) and imipenem (82.0%).The prevalence of extended-spectrum β-lactamase was 62.8%(137/218)in Escherichia coli and 28.3%(58/205)in Klebsiella pneumonia.The activity of antimicrobial agents against E.cloacae, E.aerogenes and Citrobacter freundii was as follows in descending order of susceptible rate: meropenem (97.0%-98.5%), amikacin (95.8%-98.3%), imipenem (94.5%-97.5%), polymyxin B (96.4%-100%), cefoperazone-sulbactam (76.5%-90.0%), ertapenem (73.3%-90.1%), piperacillin/tazobactam (82.4%-88.3%).The most active agents against Pseudomonas aeruginosa were polymyxinB (100%), followed by amikacin (89.3%) and ciprofloxacin (82.4%).The most active agents against Acinetobacter baumannii were polymyxinB (100%).The sensitivities of Acinetobacter baumannii to meropenem, imipenem, minocycline and cefoperazone-sulbactam were 20.3%(39/202), 19.3%(41/202), 66.3%(134/202) and 24.8%(50/202), respectively.Conclusions Carbapenems remain high sensitive against Enterobacteriaceae.Controlling carbapenem resistant Klebsiella pneumoniae is urgent.Drug antimicrobial resistance in A.baumanni is a still serious problem.
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Objective To investigate the homology of carbapenem-resistant Klebsiella pneumoniae (CR-KPN) isolates by multilocus sequence typing (MLST) method,and profile CR-KPN infections in terms of MLST sequence types (STs).Methods A total of 61 CR-KPN isolates were collected in five hospitals from Liaoning Province from January 2013 to June 2015.The MICs of 14 antimicrobial agents against these isolates were determined by broth microdilution method.The genotypes of carbapenemases were analyzed by PCR and DNA sequencing techniques.The homology of CR-KPN isolates were analyzed by MLST method.The clinical data of patients with CR-KPN infection were reviewed to characterize CR-KPN infections.Results A total of 18 STs were identified among the 61 CR-KPN strains according to MLST data.More than 50 ％ of the isolates belonged to ST11 (53.3 ％).ST11 strains showed higher resistance rate to carbapenems and higher prevalence of KPC-2 type carbapenemase.Univariate analysis indicated that more ST 11-infected patients were treated in ICU and with mechanical ventilation than non-ST11 CR-KPN-infected patients (P＜0.05).ST2033,ST2135,ST2193,ST2194,ST2195 and ST2196 were the STs firstly registered in the world.The eBURST analysis showed that ST2193,ST2194,ST2195 and ST 11 were closely related.Clinical data indicated that the prevalent CR-KPN strains during the same period in the same hospital usually belonged to the same ST clone.Conclusions MLST of CR-KPN showed 18 sequence types,of which ST11 was the predominant type.Clinical data indicated that the prevalent CR-KPN strains during the same period in the same hospital usually belonged to the same ST clone.This suggests the potential of local CR-KPN outbreak.The ICU patients and those receiving mechanical ventilation may be prone to CRKPN (especially ST11) infection.Such patients should be managed appropriately.
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Objective To investigate the antibiotic resistance and resistance genes of carbapenem-resistant Enterobacteriaceaes (CRE) isolated from 5 hospitals in Northeast China.Methods This study collected 85 CRE isolates during January 2013 to June 2015 from five hospitals in Northeast China.Drug sensitivities of 14 antimicrobial agents were determined by the broth microdilution method.The phenotypes of carbapenemases were screened by modified Hodge test and EDTA test respectively.The genotypes of carbapenemases and other extended spectrum β-lactamases (ESBL) were detected by PCR gene amplification and DNA sequencing method.Using the PCR result as gold standard, the performances of other two carbapenemase detection methods were evaluated.Results Among the 85 CRE strains collected in this study, Klebsiella pneumoniae was the most frequently isolated species (61/85,71.8%).The results of antimicrobial agent sensitivity showed that the 85 CRE strains had resistance rate of cephalosporin and β-lactams/enzyme inhibitor (piperacillin-tazobactam) over 80.0%.The resistance rate of carbapenem was high, with ertapenem 100.0% (85/85), meropenem 65.9% (56/85), imipenem 71.8% (61/85).There were 36 isolates resistant to both meropenem and imipenem.For fluoroquinolones, the resistance rates of levofloxacin and ciprofloxacin were 72.9% (62/85) and 65.9% (56/85), respectively.The resistance rate to fosfomycin and amikacin were 65.0% (55/85) and 54.1% (46/85), respectively.The resistance rate of colistin (21.2%, 18/85) and tigecycline (20.5%, 17/85) were low.Forty-nine strains were modified Hodge test positive and 12 strains were EDTA test positive.By PCR gene amplification and DNA sequencing method, 64 strains carried carbapenemase-encoding genes, of which KPC-2 was the main type (53/85, 62.4%), followed by IMP-4 (10/85, 11.8%), NDM-5 (7/85, 8.2%) and NDM-6 (1/85, 1.2%).At the same time, 85 CRE isolates had the ESBL gene detection and 47 isolates were CTX-M type ESBLs (47/85, 55.3%), with no TEM or SHV type.Conclusions Klebsiella pneumoniae is the majority of CRE strains from 5 large hospitals in Northeastern China.The CRE strains are resistant to most of antimicrobials.Most carbapenemases-producing isolates have the KPC-2 type.Nearly half of the carbapenemase-producing strains also carry ESBL genes, which makes the resistance mechanisms more complicated.
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Objective To evaluate the changing pattern of antibiotic resistance inKlebsiella strains isolated from the patients in 19 hospitals across China based on the data from CHINET Antimicrobial Resistance Surveillance Program during the period from 2005 through 2014.Methods Kirby-Bauer disk diffusion and automated susceptibility testing methods were used to test the susceptibility ofKlebsiella isolates to the commonly used antibiotics. The results were interpreted according to the criteria of the Clinical and Laboratory Standards Institute (CLSI) Performance Standards for Antimicrobial Susceptibility Testing (CLSI-2014).Results A total of 61 406Klebsiella strains were identified between 2005 and 2014, includingK. pneumoniae (56 281 strains), K. oxytoca(4 779),Klebsiella pneumoniae subsp.Ozaenae (300) and otherKlebsiella species (46). Most (89.0%, 54 664/61 406) of theKlebsiella strains were isolated from inpatients, and 60.0% (36 835/61 406) were from respiratory tract speciems. About 16.7% (10 248/61 406) of the strains were isolated from pediatric patients aged 0-17 years and 83.3% (51 158/61 406) from adult patients. The prevalence ofKlebsiella spp. increased with time from 10.1% in 2005 to 14.3% in 2014. Based on the surveillance data during the 10-year period, we found a marked increase of resistance to imipenem (2.9% to 10.5%) and meropenem (2.8% to 13.4%) inKlebsiella spp. The prevalence of ESBLs-producing isolates inK. pneumoniae andK. oxytoca decreased from 39.0% in 2005 to 30.1% in 2014. The resistance to amikacin, ceftazidime, ciprolfoxacin, pipracillin-tazobactam and cefoperazone-sulbactam was on decline. The resistance rate to cefotaxime remained high about 49.5%. Carbapenem resistantance was identiifed in 5 796 (9.4%) of the isolates, including 5 492 strains ofK. pneumoniae and 280 strains ofK. oxytoca. Overall, 4 740 (7.8%) strains were identiifed as extensively-drug resistant (XDR), including 4 520 strains ofK. pneumoniae and 202 strains ofK. oxytoca. The carbapenem-resistant strains showed high (>60%) resistance rate to majority of the antimicrobial agents tested, but relatively low resistance to tigecycline (16.8%), amikacin (54.4%), and trimethoprim-sulfamethoxazole (55.5%).Conclusions During the 10-year period from 2005 through 2014, carbapenem resistance amongKlebsiella isolates has increased dramatically in the hospitals across China. The level of resistance to other antibiotics remains stable.
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Objective To investigate the distribution and antibiotic resistance proifle of clinicalEnterobacter isolates using the data from CHINET during the period from 2005 through 2014.Methods A total of 20 558 clinical strains ofEnterobacter spp. were collected from 2005 to 2014 in CHINET Antimicrobial Resistance Surveillance Program. Antimicrobial susceptibility testing was performed with Kirby-Bauer or minimum inhibitory concentration method. The results were analyzed according to CLSI 2014 breakpoints.ResultsEnterobacter cloacae andEnterobacter aerogenes accounted for 71.1% (14 617/20558) and 20.1% (4 129/20 558) of all theEnterobacterisolates, respectively. The proportion ofEnterobacter spp. increased with time from 3.5% in 2005 to 4.3% in 2014. The main source of the isolates was respiratory tract, accounting for 55.2% (11 358/20 558). More than 90% of theEnterobacterisolates were resistant to cefazolin and cefoxitin, but less than 30% of the strains were resistant to cefepime, piperacillin-tazobactam, cefoperazone-sulbactam, amikacin, gentamicin, ciprolfoxacin, meropenem, imipenem and ertapenem. TheEnterobacterisolates showed a trend of declining resistance to most antibiotics except ertapenem and meropenem. The resistance proifle ofEnterobacterisolates varied with departments where they were isolated. The strains from ICU and Department of Surgery were relatively more resistant to antibiotics. The prevalence of multi-drug resistant (MDR) strains was decreasing, but the prevalence of carbapenem-resistantEnterobacter (CRE, resistant to any of imipenem, meropenem or ertapenem) was increasing. The MDR and CRE strains were primarily isolated from ICU and Department of Surgery. At least 30% of the MDREnterobacter strains were resistant to any of the antimicrobial agents tested except meropenem, imipenem and ertapenem and at least 35% of the CRE strains were resistant to any of the antimicrobial agents tested except amikacin and ciprolfoxacin.Conclusions TheEnterobacter isolates in CHINET Antimicrobial Resistance Surveillance Program showed decreasing resistance to most of the antimicrobial agents tested since 2011, but the prevalence of CRE strains increased progressively. Effective measures should be carried out to prevent the spread of CRE strains in hospitals.
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Objective To understand the changing resistance proifle ofProteus,Serratia,Citrobacter,Morganella andProvidencia in hospitals across China according to the data from CHINET Antimicrobial Resistance Surveillance Program 2005-2014.Methods Antimicrobial susceptibility was tested by using Kirby-Bauer method or automatic minimum inhibitory concentration determination according to a uniifed protocol.Results A total of 21 663 clinical isolates were collected from January 2005 to December 2014. The proportion ofProteus andSerratia isolates increased with time from 1.41% in 2005 to 2.09% in 2014, and from 0.99% in 2005 to 1.28% in 2014 among all the isolates. No change was found for the proportion ofCitrobacter,Morganella, orProvidencia. Less than 10% of theProteus isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, ceftazidime, cefoxitin, amikacin and tigecycline. Less than 10% of theSerratia isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, amikacin and tigecycline. Less than 20% of theCitrobacter isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, amikacin and tigecycline. Less than 10% of theMorganella isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, amikacin and tigecycline. Less than 20% of theProvidencia isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, cefoxitin and tigecycline.Conclusions The antibiotic resistance ofProteus,Serratia, Citrobacter,Morganella andProvidencia isolates in hospitals across China is growing during the period from 2005 to 2014. Strengthening infection control and rational antibiotic use are effective to slow the growth of drug resistance.
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Objective To investigate the distribution and changing resistance proifle ofSalmonella isolates in hospitals across China during the period from January 2005 to December 2014.Methods Seventeen general hospitals and two children’s hospitals were involved in this program. Antimicrobial susceptibility testing was carried out by means of a unified protocol using Kirby-Bauer method or MIC determination. The results were analyzed according to CLSI 2014 breakpoints.Results The proportion ofSalmonella isolates increased with time from 0.2% in 2005 to 0.7% in 2014. A total of 3 478Salmonella strains were collected from 19 hospitals. The proportion ofSalmonella typhimurium andSalmonella enteritidis was 27.4% and 24.4%, respectively. During the 10-year period, theSalmonella strains showed highest resistance rate to ampicillin (33.3%-64.8%), but low resistance to cefoperazone-sulbactam (0-5.3%) and ciprofloxacin (2.4%-14.3%).S. typhimurium showed higher resistance rate thanS. typhi,S. paratyphi andS. enteritidis. About 76.8% and 50.5% ofS. typhimurium were resistant to ampicillin and trimethoprim-sulfamethoxazole. The average prevalence of multi-drug resistantSalmonellawas 3.9% in the ten-year period, the highest (7.5%) was in 2005, the lowest (1.5%) in 2013.Conclusions During the period from 2004 to 2015, majority of theSalmonella isolates in hospitals across China wasS. typhimurium andS. enteritidis. Ampicillin and trimethoprim-sulfamethoxazole are no longer appropriate for empirical treatment ofS. typhimurium infection due to high resistance rate.Salmonella isolates are relatively more susceptible to third-generation cephalosporins and quinolones. Ongoing monitoring is necessary to identify multi-drug resistant strains ofSalmonella.
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Objective To analyze the resistance proifle of bacterial strains isolated from geriatric patients in 17 hospitals across China from 2005 to 2014.Methods A total of 17 representative general hospitals were involved in this program. Bacterial susceptibility testing was carried out by means of a uniifed protocol using Kirby-Bauer method and MIC determination. The results were analyzed according to CLSI 2014 breakpoints.Results The proportion of the strains isolated from geriatric patients among all the clinical isolates increased with time from 30.0% in 2005 to 32.7% in 2014. A total of 159 888 clinical isolates were collected from geriatric patient during the period from 2005 to 2014, about 33.1% of the whole patient population. Gram negative organisms and gram positive cocci accounted for 77.1% (123 229/159 888) and 22.9% (36 659/159 888), respectively. Majority (92.8%, 148 376/159 888) of the isolates were from inpatients and more than half (55.2%, 88 201/159 888) of the isolates were from sputum or other respiratory tract specimens. Methicillin-resistant strains inS. aureus (MRSA) and coagulase negativeStaphylococcus (MRCNS) accounted for an average of 67.1% and 75.9%, respectively. The resistance rates of methicillin-resistant strains to β-lactams and other antimicrobial agents were much higher than those of methicillin-susceptible strains. No staphylococcal strains were found resistant to vancomycin, teicoplanin or linezolid. Some strains ofE. faecalis (0.4%) andE. faecium (4.6%) were resistant to vancomycin, which was higher than average national level (0.3%, 3.2%). Vancomycin-resistant strains ofE. faecalisandE. faecium were mainly VanA type and VanB type based on their phenotype. The prevalence of penicillin-susceptibleS. pneumoniae strains was 78.2%, slightly lower than the 95.0% in Chinese adults in year 2014. The prevalence of ESBLs-producing strains was 67.5% inE. coli, 40.4% inKlebsiella (K. pneumoniae andK. oxytoca) and 34.3% inProteus mirabilis isolates on average. The strains ofEnterobacteriaceae were still highly susceptible to carbapenems (<10% resistant), followed by amikacin and the beta-lactam and beta-lactamase inhibitor combinations. Overall, 35.9% and 33.0% of theP. aeruginosa strains were resistant to imipenem and meropenem. More than 50% of theA. baumannii strains were resistant to imipenem and meropenem. The prevalence of extensively drug-resistant (XDR)P. aeruginosa (4.0%-1.8%) was higher than the average national level (2.1%-1.6%). The prevalence of XDR A. baumannii (19.2%-15.5%) and XDREnterobacteriaceae (0.1%-1.0%) was lower than the average national level (21.4%-19.7% and 0.3%-3.2%).Conclusions The proportion of clinical isolates from geriatric patients is different from average national level at the same period. The isolates from geriatric patients are more likely from inpatients, respiratory tract specimens and more likely non-fermentative gram-negative bacilli compared to average national level. The proportion of fastidious bacteria andEnterobacteriaceae species is generally lower than average national level. MRSA, VRE, ESBLs-producing strains and XDRP. aeruginosa are more prevalent in geriatric patients than in general Chinese patient population. This study suggests that surveillance of antimicrobial resistance for the clinical isolates from geriatric patients is very important for rational antimicrobial therapy.
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Objective Toinvestigateantimicrobialresistanceamonggram-positivecocciinChinain 2013.Methods Retrospectivestudy.FromJune2013toDecember2013,1663consecutiveandnon-repetitive gram-positive cocci were collected from 15 teaching hospitals. The minimal inhibitory concentration ( MIC) of antibacterial agents was determined by agar dilution method. A retrospective study was conducted on rates of resistance to antimicrobial agents. The prevalence of penicillin-resistant Streptococcus pneumoniae ( PRSP) between children and adult patients and the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) between elder group and younger adult patients were compared using chi-square test. Results The prevalence of PRSP in children below 3 years old ( 72. 9%, 51/70 ) was higher than adult patients (55. 2%, 106/192) (χ2 =6. 653,P<0. 05). About 94. 9%(261/275) and (92. 7%,255/275) of S. pneumonia were resistant to erythromycin and clindamycin. All S. pneumoniae strains were susceptible to teicoplanin, vancomycin, linezolid, tigecycline and daptomycin. Penicillin still showed very high activity against Streptococcus spp. β-Hemolytic group. More than 60% of Streptococcus spp.β-Hemolytic group were resistant to erythromycin, clindamycin and tetracyclines. The prevalence of MRSA and methicillin-resistant coagulase-negative Staphylococci(MRCoNS) was 39. 7%(229/576) and 80. 6%(224/278), respectively. The MRSA prevalence ranged from 24. 2% to 70. 0% in different regions. About 52. 6%( 100/190 ) of Staphylococcus aureus from respiratory tract specimens, 38. 5%(40/104)of Staphylococcus aureus from blood samples, and 29. 7%(58/195) of Staphylococcus aureus from wound and pus were resistant to methicillin. The prevalence of MRSA in elder group ( 48. 6%, 84/173 ) was higher than that in younger adult patients (35. 7%, 144/403)(χ2 =8. 322,P <0. 05). The susceptibility rates of MRSA to chloramphenicol and trimethoprim/sulfamethoxazole were 86. 4% ( 244/228 ) and 94. 7% ( 237/228 ) , respectively. Susceptibility rates to gentamycin, erythromycin, clindamycin, tetracyclines, rifampicin and quinolones were ranged from 15. 8% to 59. 6%. All Staphylococci isolates were susceptible to teicoplanin, vancomycin, linezolid, daptomycin and tigecycline. All Enterococcus isolates were susceptible to daptomycin and tigecycline. All E. faecalis ( 158/158 ) and 96. 4% ( 133/138 ) of E. faecium were susceptible to teicoplanin. About 98. 0% ( 150/153 ) of E. faecalis and 97. 1% ( 145/138 ) of E. faecium were susceptible to linezoild. About 45. 8% (70/153) of E. faecalis and 60. 9% (84/138) of E. faecium were resistant to gentamycin with a high concentration. The susceptibility of E. faecalis to all the antibiotics tested exceptchloramphenicolandtetracyclinewashigherthanthatofE.faecium.Conclusions Basedon different age groups and regions, the resistance rates of Gram-positive cocci are different. Teicoplanin, vancomycin, tigecycline, daptomycin, linezolid and tedizolid showed very high activity against Gram-positive cocci. (Chin J Lab Med,2015,38:373-381)
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Objective To investigate the susceptibility and resistance of clinical isolates collected from hospitals in several regions of China . Methods Fourteen general hospitals and two children ’ s hospitals were involved in this program . Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated Systems .Results were analyzed according to CLSI 2013 breakpoints .Results A total of 84 572 clinical isolates were collected from January to December 2013 ,of which gram negative organisms and gram positive cocci accounted for 73 .0% and 27 .0%respectively .Methicillin-resistant strains in S .aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) accounted for an average of 45 .2% and 73 .5% respectively .The resistance rates of methicillin-resistant strains to β-lactams and other antimicrobial agents were much higher than those of methicillin-susceptible strains .However ,92 .2% of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole while 87 .4% of MRCNS strains were susceptible to rifampin . No staphylococcal strains were found resistant to vancomycin ,teicoplanin or linezolid .In Enterococcus spp .,the resistance rates of E . f aecalis strains to most tested drugs (except chloramphenicol) were much lower than those of E . f aecium .Some strains of both species were resistant to vancomycin .Vancomycin-resistant strains of E . f aecalis and E . f aecium were mainly VanA type based on their phenotype .Regarding non-meningitis S . pneumoniae strains ,the prevalence of penicillin-susceptible S . pneumoniae and penicillin-intermediate S . pneumoniae strains isolated from both adults and children were lower than those isolated in 2012 ,but the prevalence of penicillin-resistant S .pneumoniae strains increased .The prevalence of ESBLs producing strains was 54 .0% in E .coli ,31 .8% in Klebsiella spp .(K .pneumoniae and K .oxytoca) and 16 .5% in Proteus mirabilis isolates on average . ESBLs-producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains in terms of antibiotic resistance rates .The strains of Enterobacteriaceae were still highly susceptible to carbapenems .Overall less than 7 .0% of these strains were resistant to carbapenems .About 62 .8% and 59 .4% of Acinetobacter spp .(A .baumannii accounts for 89 .2% ) strains were resistant to imipenem and meropenem ,respectively .Compared with the data of year 2012 , extensively-drug resistant strains in K . pneumoniae and A . baumannii decreased .Conclusions The antibiotic resistance of clinical bacterial isolates is growing in 2013 .The disseminated multi-drug or pan-drug resistant strains in a special region poses a serious threat to clinical practice and implies the importance of strengthening infection control .
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Objective To investigate the distribution and susceptibility of carbapenem-resistant Enterobacteriaceae (CRE) isolates in 2012 from CHINET surveillance .Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated Systems .Results were analyzed according to the breakpoints of CLSI 2012 M100-S22 .Results A total of 1 499 CRE isolates were collected from January to December 2012 ,of which K lebsiella spp .,Enterobacter spp .and E .coli accounted for 63 .5% ,15 .1% and 13 .7% ,respectively .Of the 1 499 isolates , 48 .2% and 29 .3% were from respiratory tract and ICU , respectively . The results of antimicrobial susceptibility testing showed that the resistance rate of CRE isolates to most antimicrobial agents was 70 .0%-100% except amikacin (46 .9% ) and trimethoprim-sulfamethoxazole (49 .8% ) .CRE isolates from adults were more resistant to ciprofloxacin ,aminoglycosides and trimethoprim-sulfamethoxazole than those from children .Conclusions The antibiotic resistance of CRE isolates is very high . The spread of CRE strains in a specific region such as ICU and neurosurgery ward poses a serious threat to clinical practice and implies the importance of strengthening infection control .
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Objective To investigate the distribution and antibiotic resistance of clinical Enterobacter isolates .Methods A total of 3 031 clinical strains of Enterobacter were collected from 15 hospitals from January 1 through December 31 , 2012 . Antimicrobial susceptibility testing was performed with Kirby-Bauer or minimum inhibitory concentration method .The results were analyzed according to CLSI 2012 breakpoints .Results Enterobacter cloacae and Enterobacter aerogenes accounted for 73 .0% (2 212/3 031) and 23 .9% (725/3 031) of all the Enterobacter strains .The isolates of other Enterobacter species accounted for 3 .1% (94/3 031 ) . The main source of the isolates was respiratory tract specimen , accounting for 53 .2% (1 612/3 031) .Most (> 89% ) of the Enterobacter strains were resistant to cefazolin and cefoxitin . Generally ,54 .4% ,47 .5% and 34 .3% of the strains were resistant to cefuroxime ,cefotaxime and cefazidime ,respectively . About 6 .6% to 26 .3% of the strains were resistant to amikacin ,gentamicin ,piperacillin-tazobactam ,cefepime ,cefoperazone-sulbactam ,ciprofloxacin and trimethoprim-sulfamethoxazole .Imipenem ,meropenem and ertapenem showed the highest activity , to which only 3 .5% ,3 .7% and 10 .3% of the strains were resistant ,respectively .About 8 .9% (269/3 031) of the strains were resistant to at least imipenem ,meropenem or ertapenem .Four Enterobacter strains were extensive-drug resistant (XDR) .Conclusions The prevalence of antibiotic resistance in Enterobacter isolates decreased slightly in 2012 compared to the data in 2011 ,but the situation is still very serious .We should continue to take effective measures to control the resistant strains .
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Objective To investigate the antimicrobial resistance in the A cinetobacter baumannii strains in different parts of China during 2012 .Methods A total of 8 739 clinical isolates of Acinetobacter were collected from 13 general hospitals and two children’s hospitals ,of which most were A . baumannii (89 .6% , 7 827/8 739 ) . Antimicrobial susceptibility testing was carried out by means of Kirby-Bauer method according to the unified protocol . The susceptibility testing data were analyzed by WHONET 5 .6 software according to CLSI 2013 breakpoints .Results Majority (85 .4% ) of the Acinetobacter strains were isolated from inpatients .The remaining 14 .6% were from outpatients and emergency room patients .Of the 7 827 strains of A .baumannii , 10 .9% ,35 .2% ,35 .7% and 43 .4% were resistant to tigecycline ,minocycline ,cefoperazone-sulbactam and amikacin , respectively .The percentage of A .baumannii resistant to imipenem and meropenem was 63 .5% and 68 .2% ,respectively . The antimicrobial resistant pattern varied in different hospitals . The resistance of A . baumannii varied between different clinical departments .A number of pandrug resistant (PDR) (20 .0% ,1 567/7 827) and multidrug-resistant (MDR) (45 .0% , 3 521/7 827 ) A . baumannii were identified . Conclusions A . baumannii is the most popular pathogenic bacteria among Acinetobacter .The antibiotic resistance of A .baumannii is still increasing .Cefoperazone-sulbactam and minocycline has good in vitro antibacterial activity against A .baumannii .The antibiotic resistance of A .baumannii varies greatly with hospital and department .