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Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.
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Objective:To investigate the distribution and antimicrobial resistance profile of clinical bacteria isolated from blood culture in China.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2018 to December 2019. Antibiotic susceptibility tests were conducted with agar dilution or broth dilution methods recommended by US Clinical and Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 14 778 bacterial strains were collected from 50 hospitals, of which 4 117 (27.9%) were Gram-positive bacteria and 10 661(72.1%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.2%), Klebsiella pneumoniae (17.0%), Staphylococcus aureus (9.7%), coagulase-negative Staphylococci (8.7%), Pseudomonas aeruginosa (3.7%), Enterococcus faecium (3.4%), Acinetobacter baumannii(3.4%), Enterobacter cloacae (2.9%), Streptococci(2.8%) and Enterococcus faecalis (2.3%). The the prevalence of methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus were 27.4% (394/1 438) and 70.4% (905/1 285), respectively. No glycopeptide-resistant Staphylococcus was detected. More than 95% of S. aureus were sensitive to amikacin, rifampicin and SMZco. The resistance rate of E. faecium to vancomycin was 0.4% (2/504), and no vancomycin-resistant E. faecalis was detected. The ESBLs-producing rates in no carbapenem-resistance E. coli, carbapenem sensitive K. pneumoniae and Proteus were 50.4% (2 731/5 415), 24.6% (493/2001) and 35.2% (31/88), respectively. The prevalence of carbapenem-resistance in E. coli and K. pneumoniae were 1.5% (85/5 500), 20.6% (518/2 519), respectively. 8.3% (27/325) of carbapenem-resistance K. pneumoniae was resistant to ceftazidime/avibactam combination. The resistance rates of A. baumannii to polymyxin and tigecycline were 2.8% (14/501) and 3.4% (17/501) respectively, and that of P. aeruginosa to carbapenem were 18.9% (103/546). Conclusions:The surveillance results from 2018 to 2019 showed that the main pathogens of bloodstream infection in China were gram-negative bacteria, while E. coli was the most common pathogen, and ESBLs-producing strains were in majority; the MRSA incidence is getting lower in China; carbapenem-resistant E. coli keeps at a low level, while carbapenem-resistant K. pneumoniae is on the rise obviously.
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Objective:To explore the clinical value of heparin binding protein (HBP) in bronchoalveolar lavage fluid (BALF) for diagnosis and differential diagnosis of bacterial pneumonia.Methods:Eighty eight patients with pulmonary infection from the respiratory department of the Fourth Affiliated Hospital of Anhui Medical University from January 2019 to January 2021 were enrolled in the study, including 48 cases of bacterial pneumonia and 40 cases of non-bacterial pneumonia; meanwhile, 40 non-pulmonary infection patients were also enrolled as the control group. The BALF levels of HBP, procalcitonin (PCT), interleukin-6 (IL-6) were measured, and the clinical values of the above indexes in differential diagnosis of bacterial and non-bacterial pneumonia were analyzed.Results:The BALF levels of HBP and IL-6 in bacterial pneumonia group were significantly higher than those of the non-bacterial pneumonia group and the control group ( P<0.05). ROC curve showed that the areas under the curve (AUC) of HBP and IL-6 were 0.930 and 0.893 for the early diagnosis of bacterial pneumonia; and the sensitivity was 88.5% and 82.7%, the specificity was 92.5% and 92.5%, respectively. Combined detection of HBP and IL-6, the AUC was 0.942 and the sensitivity was 94.2% and the specificity was 95.0%. When they were used to distinguish bacterial pneumonia, the AUC of HBP and IL-6 were 0.890 and 0.777, and the sensitivities were 80.8% and 71.2%, and the specificity were 91.7% and 75.0%, respectively. Combined detection of HBP and IL-6, the AUC was 0.902, and the sensitivity was 96.2% and the specificity was 79.2%. Conclusions:BALF HBP and IL-6 have good clinical value in the early diagnosis and distinguishing bacterial pulmonary infection and the joint value of the two is better.
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Objective:To investigate the bacterial composition and antimicrobial resistance profile of clinical isolates from bloodstream infections in China.Methods:The clinical bacterial strains isolated from blood culture were collected during January 2020 to December 2020 in member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS). Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute(CLSI, USA). WHONET 5.6 was used to analyze data.Results:During the study period, 10 043 bacterial strains were collected from 54 hospitals, of which 2 664 (26.5%) were Gram-positive bacteria and 7 379 (73.5%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (38.6%), Klebsiella pneumoniae (18.4%), Staphylococcus aureus (9.9%), coagulase-negative Staphylococci (7.5%), Pseudomonas aeruginosa (3.9%), Enterococcus faecium (3.3%), Enterobacter cloacae (2.8%), Enterococcus faecalis (2.6%), Acinetobacter baumannii (2.4%) and Klebsiella spp (1.8%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 27.6% and 74.4%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci were detected. More than 95% of Staphylococcus aureus were sensitive to rifampicin and SMZco. No vancomycin-resistant Enterococci strains were detected. Extended spectrum β-lactamase (ESBL) producing Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 48.4%, 23.6% and 36.1%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.3% and 16.1%, respectively; 9.6% of carbapenem-resistant Klebsiella pneumoniae strains were resistant to ceftazidime/avibactam combination. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii. The prevalence rate of carbapenem-resistance of Pseudomonas aeruginosa was 23.2%. Conclusions:The surveillance results in 2020 showed that the main pathogens of bloodstream infection in China were gram-negative bacteria, while Escherichia coli was the most common pathogen, and ESBL-producing strains declined while carbapenem-resistant Klebsiella pneumoniae kept on high level. The proportion and the prevalence of carbapenem-resistant Pseudomonas aeruginosa were on the rise slowly. On the other side, the MRSA incidence got lower in China, while the overall prevalence of vancomycin-resistant Enterococci was low.
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Objective To analyze the distribution and antimicrobial resistance profile of clinical bacterial strains isolated from blood culture in China.Methods Clinical bacterial strains isolated from blood culture from participating hospitals of Blood Bacterial Resistance Investigation Collaborative System (BRICS) during January 2014 to December 2015 were collected.Antibiotic susceptibility tests were conducted with agar dilution or broth dilution methods as recommended by US Clinical and Laboratory Standards Institute(CLSI)2018.The data were analyzed with Whonet 5.6 software.Results During the study period,4 801 clinical bacterial isolates were collected from 26 hospitals,of which 1 798 (37.5％) were Gram-positive bacteria and 3 003 (62.5％) were gram-negative bacteria.The top 10 isolates were Escherichia coli (33.8％),coagulase-negative Staphylococcus (19.0％),Klebsiella pneumoniae (11.9％),Staphylococcus aureus (10.1％),Acinetobacter baumannii (4.0％),Pseudomonas aeruginosa (3.8％),Streptococcus (3.0％),Enterobacter sulcus (2.9％),Enterococcus faecium (2.8％) and Enterococcus faecalis (1.8％).Methicillin-resistant Staphylococcus aureus (MRSA) and methicillinresistant coagulase-negative Staphylococcus (MRCNS) accounted for 33.9％ (165/487) and 56.9％ (520/913) of Staphylococcus aureus and coagulase-negative Staphylococcus respectively.No vancomycinresistant Staphylococcus was detected.The resistance rate of Enterococcus faecium to vancomycin was 0.7％ (1/135),and no vancomycin-resistant Enterococcus faecaliss was detected.The positive rates of extendedspectrum β-1actamases(ESBLs)-producing Escherichia coli,Klebsiella pneumoniae and Proteus were 56.9％ (923/1 621),30.1％ (172/572) and 29.2％ (7/24),respectively.The positive rates of carbapenemresistant Escherichia coli,Klebsiella pneumoniae,Enterobacter,Salmonella and Citrobacter were 1.2％ (20/1 621),7.2％ (41/572),4.3％ (6/141),1.5％ (1/67) and 2.9％ (1/34),respectively.The resistance rates of Acinetobacter baumannii to polymyxin and tegacycline were 2.6％ (5/190) and 8.9％ (17/190)respectively,and that of Pseudomonas aeruginosa to polymyxin and fosfomycin were 1.1％ (2/183)and 0.6％ (1/183),respectively.Conclusions The surveillance results from 2014 to 2015 show that the main pathogens of blood stream infection in China are Gram-negative bacteria,while Escherichia coli is the most common pathogen,the detection rate of MRSA is lower than other surveillance data in the same period in China;carbapenem-resistant Klebsiella pneumoniae and Escherichia coli are at a low level as shown in this surveillance.
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Objective To investigate the antibiotic resistance of clinical isolates in the First Affiliated Hospital of Anhui Medical University during 2017. Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using automated system or Kirby-Bauer method. Results were interpreted according to the breakpoints of CLSI 2017. The data were analyzed by WHONET 5.6 software. Results A total of 6 495 non-duplicate clinical isolates were collected in 2017. There were 1 727 strains (26.6％) of gram-positive bacteria and 4 768 strains (73.4％) of gram-negative bacteria. The most frequently isolated microorganisms were E. coli (19.8％), followed by Klebsiella pneumoniae and Acinetobacter baumannii. The strains were mainly isolated from respiratory tract (37.0％) and urine (23.1％). The prevalence of MRSA and MRCNS in Staphylococcus aureus and coagulase-negative Staphylococcus was 50.1％ and 82.1％, respectively. No Staphylococcus strains were found resistant to vancomycin or linezolid. E. faecalis and E. faecium accounted for 49.9％ and 40.4％ of total Enterococcus isolates. The prevalence of ESBLs-producing strains was 57.6％ in E. coli, 27.1％ in Klebsiella spp. and 33.0％ in Proteus mirabilis. Enterobacteriaceae strains were still highly susceptible to carbapenems antibiotics. The Klebsiella pneumoniae isolates in 2017 showed significantly higher resistance rate to imipenem and meropenem than the strains in 2016. However, Pseudomonas aeruginosa and Acinetobacterbaumannii strains showed lower resistance rates to carbapenems than the strains in 2016. Conclusions The bacterial isolates in 2017 pose serious threat to clinical antibiotic therapy. More attention should be paid to rational use of antimicrobial agents and infection control measures.
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Objective To report the distribution and antibiotic resistance of bacterial strains isolated in the First Affiliated Hospital of Anhui Medical University during 2016 for improving clinical treatment of bacterial infections. Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. The results were interpreted according to the clinical and laboratory standards institute (CLSI) 2015 breakpoints, and analyzed using WHONWT 5.6. Results A total of 5 406 clinical isolates were collected during 2016, of which gram positive organisms accounted for 25.6％ (1 386/5 406) and gram negative organisms 74.4％ (4 020/5 406). The strains were mainly isolated from respiratory tract (35.4％, 1 913/5 406) and urine (26.7％, 1 441/5 406). The most frequently isolated microorganisms were E. coli (23.1％, 1 247/5 406), followed by K. pneumoniae (12.1％,654/5 406). The prevalence of MRSA was 52.2％ (166/318). The prevalence of MRCNS was 80.3％ (462/575). Of the ESBLs producers, E. coli accounted for 59.7％ (745/1 247), and K. pneumoniae accounted for 30.6％(200/654). ESBLs-producing strains showed significantly higher resistance rates to most antibiotics than non-ESBLs-producing strains. All the E. faecalis strains were susceptible to vancomycin. A few (0.2％) of the E. faecium strains were resistant to vancomycin, which were all from urine specimens. A total of 1 046 (19.3％, 1 046/5 406) carbapenemresistant strains were isolated. Most Enterobacteriaceae isolates were still highly sensitive to carbapenems. Carbapenem-resistant isolates were mainly A. baumannii (41.1％, 430/1 046), P. aeruginosa (17.4％, 182/1 046)) and K. pneumoniae (12.0％, 126/1 046). Most Acinetobacter strains were resistant to most of the antibiotics tested. Conclusions Antimicrobial resistance is increasing in the clinical isolates in this hospital. We should continue to strengthen antimicrobial stewardship, prescribe antibiotics for strict indications, and improve rational antibiotic use.
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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 distribution and the antibiotic resistance profile of clinical isolates in the First Affiliate Hospital of Anhui Medical University during 2015.Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method and automated systems.Results A total of 5 524 nonduplicate clinical isolates were collected during 2015,including gram-negative bacteria (3 882,70.3 ％),gram-positive bacteria (1 642,29.7 ％).The prevalence of methicillin-resistant isolates in Staphylococcus aureus (MRSA) and coagulase-negative Staphylococcus (MRCNS) was 57.6％ and 83.0 ％,respectively.All staphylococcal isolates were susceptible to vancomycin and linezolid.E.faecalis and E.faecium accounted for 46.1％ and 46.8 ％ of enterococcal isolates.Some E.faecalis and E.faecium strains were nonsusceptible to vancomycin or linezolid.The prevalence of extended-spectrum lactamases (ESBLs) positive strains was 62.0 ％ in E.coli,32.2 ％ in Klebsiella and 18.8 ％ in Proteus mirabilis.Enterobacteriaceae strains were still highly susceptible to carbapenem antibiotics,evidenced by lower resistance rate of Enterobacteriaceae strains to ertapenem,imipenetn and meropenem (a11＜22 ％).Conclusions It seems that antibiotic resistance still poses a serious threat to clinical antimicrobial therapy.More attention should be paid to resistance surveillance and rational use of antibiotics.
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A rapid and sensitive method of loop-mediated isothermal amplification(LAMP) was established to detect Pseudomonas aeruginosa(P.aeruginosa).Three pairs of LAMP primers(inner,outer and ring primers) were designed according to the gbca gene of P.aeruginosa.Since adding hydroxy naphthol blue(HNB) to the reaction system, a positive reaction was indicated by a colorchange before and after the reaction,and was verified by agarose gellectrophoresis.Both LAMP and PCR were applied to detect clinical specimens, the sensitivity and specificity of the detection method were evaluated,and were compared with those of conventional PCR.A LAMP method for detecting P.aeruginosa was successfully established.The LAMP method showed specificity for P.aeruginosa without other bacteria amplification.The established LAMP method in this study enables rapid,sensitive and specific detection of P.aeruginosa,and can be applied for grass roots and small scale laboratories as well as field surveillance.
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Objective To investigate the profile and antibiotic resistance of bacteria in patients with ascites infection in intensive care unit (ICU) patients in order to provide a reference for rational clinical use of antibiotics. Methods A retrospective analysis was conducted. The bacteria isolated from ascetic fluid patients admitted from January 1st, 2004 to October 31st, 2015 to ICU of the First Affiliated Hospital of Anhui Medical University were identified, and their susceptibility to antibiotics was analyzed. Patients, who were admitted from January 1st, 2004 to December 31st, 2009 were assigned to group A, and patients admitted afterwards were assigned to group B. Results A total of 637 specimens of ascetic fluid were examined, with 185 positive culture (29.0%) during the 12 years, and 203 strains of bacteria were found. Among them 126 strains (62.1%) of gram-negative bacteria (G-), 54 (26.6%) of gram-positive bacteria (G+) and 23 (11.3%) strains of fungi were found. Compared the result of group B with that of group A, the proportion of G- bacteria was increased [71.2% (99/139) vs. 44.2% (27/64)], and that of G+ decreased [17.3% (24/139) vs. 46.9% (30/64)] in group B. The difference was statistically significant (χ2 = 20.34, P = 0.001). The main pathogenic bacteria were G-, and Enterobacteriaceae was the most common pathogenic bacteria in intra-abdominal infection of ICU patients. The isolation rate of Escherichia coli and Klebsiella pneumoniae(35.7%, 10.3%) ranked in the first and third in G- bacteria, respectively. The resistant rate of Escherichia coli against penicillin and third generation cephalosporin were > 95.0% and > 73.3%, and it showed a sensitive rate of 70% to β-lactam/inhibitor, amikacin and minocycline, and a higher sensitivity to carbapenems and tigecycline (11.1%, 0). Forty-eight strains of non-fermentation bacteria were found with a rate of 23.7%. The positive rates of Acinetobacter baumannii in groups A and B were 7.8% (5/64) and 23.7% (33/139), respectively, and they ranked first among non-fermentation bacteria. Twenty strains (62.5%) multidrug-resistant Acinetobacter baumannii were found. Acinetobacter baumannii showed a resistance rate of 84.6% to cefoperazone/sulbactam, 35.3% to minocycline, and 53.3% to tigecycline. Candida albicans was the most commonly isolated fungus in intra-abdominal infections (87.5%). No strains resistant to common antifungal drugs were isolated. Conclusions G- bacteria was the main pathogen in intra-abdominal infection in patients with ascites. Non-fermenters showed an increasing trend of producing infection, and the proportion of multidrug-resistant Acinetobacter baumannii infection increased year by year, and more attention should be taken by attending doctors.
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Objective To investigate the clinical features and prognostic factors of nosocomially acquired candidemia.Methods A retrospective analysis was conducted for hospitalized patients with nosocomial candidemia between January 2012 and December 2014 at the First Affiliated Hospital of Anhui Medical University.The univariate and multivariate Logistic regression analyses were used to determine the prognostic factors of candidemia.Results A total of 92 patients were diagnosed with nosocomially acquired candidemia.The most common pathogen was Candida glabrata (C.glabrata,39/92,42.4％),followed by Candida albicans (C.albicans,30/92,32.6％),then Candida krusei (C.krusei,7/92,7.6％),Candida tropicalis (C.tropicalis,5/92,5.4％),Candida parapsilosis (C.parapsilosis,4/92,4.4％) and other Candida spp.(7/92,7.6％).The sensitivity rates of Candida spp.strains against flucytosine,amphotericin B,voriconazole,fluconazole and itraconazol were 100.0％,98.9％,92.4％,82.6％oo and 77.2％,respectively.The 30-day attributable case fatality rate was 13.0％(12/92).Multivariate Logistic regression analyses indicated that presence of central venous catheter (OR=4.833,95％CI:1.010-23.125,P=0.049),invasive mechanical ventilation (OR=6.075,95％CI:1.144-32.257,P=0.034),and receiving hemodialysis (OR =8.367,95 ％ CI:1.390-50.364,P =0.020)were factors independently correlated with increased mortality.Conclusions The pathogens causing nosocomially acquired candidemia are mainly C.glabrata,C.albicans and C.krusei.The drug susceptibility of Candida spp.varies among fluconazole,itraconazol voriconazole.The resistant rates of Candida spp.against voriconazole,fluconazole and itraconazol are different.The presence of central venous catheter,invasive mechanical ventilation and receiving hemodialysis are factors independently correlated with increased mortality.
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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 To study the relationship between efflux pump MexAB‐OprM and carbapenem resistance of Pseudomonas aerginosa strains .Methods The minimum inhibitory concentrations of imipenem and meropenem were determined by agar dilution method for 75 strains of P .aerginosa in the absence or presence of MC207110 to screen the phenotypes of active efflux pump .Reverse transcriptase‐polymerase chain reaction (RT‐PCR) method was used to determine the mRNA expression level of mexA which encodes the membrane fusion protein in active efflux pump MexAB‐OprM and the reference (housekeeping) gene rpoD .PCR method was used to amplify the regulatory genes mexR ,nalC ,and nalD of active efflux pump MexAB‐OprM in the strains overexpressing the efflux pump . The PCR products were subject to DNA sequencing and BLAST analysis . Results Of the 75 P .aeruginosa strains ,13 (17 .3% ) were positive for efflux pump MexAB‐OprM .Overexpression of the efflux pump was identified in 10 of the 13 strains and associated with positive regulatory genes mexR ,nalC and nalD .A Gly71→Glu mutation in nalC was found in 9 strains ,and a Ser209→Arg mutation in nalC was identified in 8 strains .Only one strain had a Thr158→Ile mutation in nalD .Eight strains had mutation in mexR .Conclusions Overexpression of multidrug efflux pump MexAB‐OprM plays an important role in carbapenem resistance of P .aeruginosa .High level expression of MexAB‐OprM is related to the mutations of its regulatory genes .
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Objective To investigate the pathogens and their antibiotic resistance in patients with peritoneal dialysis‐related peritonitis .Methods The clinical data including pathogens ,antibiotic resistance profile of 213 patients with peritoneal dialysis‐related peritonitis who were treated in our peritoneal dialysis center from January 2011 to December 2013 were analyzed retrospectively .Results Dialysate culture was positive for 132 (62 .0% ) of the 213 cases ,resulting in a total of 140 strains of microorganisms ,including 84 strains of gram positive cocci ,37 strains of gram‐negative bacilli ,10 strains of fungus and 9 strains of gram positive bacilli . Coagulase‐negative Staphylococcus was the most common gram positive bacteria while Escherichia coli was the most common gram negative bacteria isolated from the effluent .The prevalence of methicillin‐resistant S .aureus and methicillin‐resistant coagulase negative Staphylococcus was 14 .3% (1/7) and 43 .2% (19/44) ,respectively . About 44 .4% (8/18) of the E .coli and K . pneumoniae isolates produced extended spectrum beta‐lactamases .All the gram‐positive cocci were sensitive to vancomycin and linezolid and slightly resistant to chloramphenicol (6 .3% ) , moxifloxacin (8 .5% ) , and rifampicin (9 .5% ) , but highly resistant to cefazolin (90 .0% ) ,followed by ampicillin (76 .7% ) ,oxacillin (71 .2% ) and penicillin (69 .7% ) . Coagulase negative Staphylococcus isolates were sensitive to vancomycin , linezolid , tigecycline , quinupristin‐dalfopristin and daptomycin ,but all resistant to cefazolin and ampicillin ,and highly resistant to penicillin (91 .9% ) and oxacillin (82 .5% ) .All the gram‐negative bacilli were sensitive to meropenem ,ertapenem ,cefoperazone‐sulbactam and tigecycline .About 80 .6% and 65 .5% of the gram‐negative bacilli were resistant to ampicillin and peperacillin ,respectively .E .coli isolates were sensitive to meropenem ,ertapenem and piperacillin‐tazobactam but highly resistant to ampicillin (81 .3% ) and piperacillin (71 .4% ) . Conclusions Gram‐positive cocci especially Staphylococcus and gram negative bacteria E .coli are major pathogens in peritoneal dialysis‐related peritonitis .Adequate microbiological culture and suitable antimicrobial therapy are key to successful treatment of the peritonitis associated with peritoneal dialysis .
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Objective To investigate the susceptibility and resistance of clinical isolates from hospitals in several regions of China .Methods Fifteen 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 2014 breakpoints .Results A total of 78 955 clinical isolates were collected from January to December 2014 ,of which gram negative organisms and gram positive cocci accounted for 72 .6% and 27 .4% ,respectively . Methicillin‐resistant strains in S .aureus(MRSA)and coagulase negative Staphylococcus(MRCNS)accounted for an average of 44 .6% and 83 .0 % ,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 .0% of MRSA strains were still susceptible to trimethoprim‐sulfamethoxazole ,while 85 .6% 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 V anA ,V anB or V anM type based on their phenotype or genotype .Regarding non‐meningitis S .pneumoniae strains ,the prevalence of penicillin‐susceptible S .pneumoniae strains isolated from both adults and children were higher than those isolated in 2013 ,but the prevalence of penicillin‐intermediate S . pneumoniae or penicillin‐resistant S . pneumoniae strains decreased . The prevalence of ESBLs producingstrainswas55.8% in E.coliand29.9% in Klebsiellaspp.(K.pneumoniaeand K.oxytoca)and24.0% 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 10 % of these strains were resistant to carbapenems . About 62 .4% and 66 .7% of Acinetobacter spp .(A .baumannii accounts for 93 .0 % ) strains were resistant to imipenem and meropenem ,respectively . Compared with the data of year 2013 ,extensively‐drug resistant strains in K . pneumoniae and A .baumannii increased . Conclusions The antibiotic resistance of clinical bacterial isolates is growing .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 .