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Objective:To retrospectively analyze the clinical characteristics and drug resistance among COVID-19 patients with bacterial and fungal infections.Methods:Clinical data of COVID-19 patients whose blood, urine, sputum and alveolar lavage fluid samples were positive for bacteria and fungi were collected in Tongji Hospital from February 10 to March 31, 2020. WHONET5.6 software was used to analyze drug susceptibility test results.Results:A total of 95 COVID-19 patients positive for pathogenic bacteria were enrolled and among them, 23 were non-critical patients and 72 were critical patients. The main symptoms in these patients included fever, cough with sputum, fatigue and dyspnea. Male and female critical patients accounted for 63.89% and 36.11%, respectively. Most of the patients with bacterial and fungal infections were critical type, accounting for 23.61%. The mortality rates of non-critical and critical patients were 13.04% and 61.11%, respectively. A total of 179 strains of pathogenic bacteria were isolated. The positive rate of Escherichia coli in non-critical patients was 37.50%, which was higher than that in critical patients. However, the positive rates of Acinetobacter baumannii and Klebsiella pneumoniae in critical patients were both 29.87%, higher than those in non-critical patients. There was no significant difference in the positive rate of gram-positive bacteria or fungi between non-critical and critical patients. It was noteworthy that the positive rate of Candida parapsilosis in blood samples of critical patients was relatively high, reaching 36.40%. Drug susceptibility test results showed that no carbapenem-resistant Escherichia coli stains were detected and 60.87% of Klebsiella pneumoniae strains were resistant to carbapenems. Acinetobacter baumannii strains were 100% resistant to three antimicrobial drugs. Methicillin-resistant Staphylococcus aureus strains accounted for 71.43%, but no vancomycin-resistant gram-positive cocci were found. Conclusions:Critical COVID-19 patients were mostly male and prone to multiple bacterial and fungal infections. The mortality of critical patients was higher than that of non-critical patients. Critical COVID-19 was often complicated by hospital acquired infections caused by bacteria including Acinetobacter baumannii and Klebsiella pneumoniae with high drug resistance.
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Objective To learn the distribution, epidemiology and antimicrobial susceptibility of diarrheagenic Escherichia coli (DEC) isolated from patients with acute diarrhea among children less than 5 years old. Methods Totally 684 stool samples collected from Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology between August 1, 2015 and September 30, 2016 were tested by culture and identified the common pathogens. PCR was applied to detect the virulence genes of DEC. Meanwhile, serotyping of enteropathogenic E. coli (EPEC) was performed by slide agglutination tests for all the isolates of EPEC. An antimicrobial sensitivity test was performed using the agar dilution method. Results A total of 149 (21.7％) enteric bacteria pathogens were isolated from 684 specimens. DEC was found in 54 cases, ranked 2nd among the pathogenic bacteria. DEC tended to occur in summer/autumn periods. EPEC was the most frequent DEC genotype, accounted for 50％ (27/54). Among EPEC, atypical EPEC was dominant, accounted for 77.8％ (21/27) and typical EPEC only accounted for 22.2％ (6/27). Followed by enteroaggregative E. coli 20.4％(11/54), enterotoxigenic E. coli 14.8％(8/54), enteroinvasive E. coli and Shiga toxin-producing E. coli 3.7％(2/54), 7.4％(4/54) cases were co-infected with more than one DEC genotypes. About 17/18 of suspicious DEC isolates can get the same genotypes by commercial multiplex PCR kit and single PCR test. Among the 27 EPEC strains, only 11(40.7％) strains can be detected by the slide agglutination serotyping method. More than 50％ (27/54) of DEC isolates were resistant to conventional first-line antibiotics (ampicillin, trimethoprim-sulfamethoxazole) and cefazolin, cefuroxime, cefotaxime, but relatively low resistance to cefoxitin, amikacin, piperacillin/tazobactam, imipenem and meropenem. However, there was still a 9.2％ (5/54) resistance rate to carbapenems. Conclusions DEC strains exhibited a high frequency of resistance to many antibiotics. Empirical antimicrobial therapy of severe DEC infection faces the challenge from the high resistance to ampicillin, trimethoprim-sulfamethoxazole. Even worse, some strains were resistant to relatively efficient drugs imipenem and meropenem. It is necessary to strengthen the epidemiological survey and antimicrobial resistance of DEC.
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Objective To study the clinical feature of carbapenem-resistant klebsiella pneumoniae (CRKP) neonatal sepsis.Method From January 2012 to December 2017,clinical data of newborns with klebsiella pneumoniae (Kp) sepsis admitted to the NICU of our hospital were retrospectively analyzed.Clinical manifestations,laboratory examinations,risk factors,treatments and outcomes were compared between newborns with CRKP sepsis and newborns with carbapenem-sensitive klebsiella pneumoniae (CSKP) sepsis.Result A total of 71 strains of Kp were isolated,representing 33.2％ of all isolated pathogens (71/214).Among 71 newborns diagnosed with Kp sepsis,35 were CRKP sepsis and the other 36 were CSKP sepsis.The incidence of dyspnea/apnea in CRKP group was significantly higher than CSKP group (85.7％ vs.55.6％,P=0.005).Newborns in CRKP group had smaller gestational age than CSKP group.The proportions of male gender,the incidences of continuous positive airway pressure treatment,parenteral nutrition and antibiotics exposure (cephalosporins,penicillins or carbapenems) before the onset of sepsis in CRKP group were higher than CSKP group and the hospital stay before sepsis was longer than CSKP group,the differences were statistically significant (P＜0.05).Logistic regression analysis showed that male gender (OR=8.125,95％CI 2.275～29.021),parenteral nutrition (OR=27.730,95％CI 2.948～260.858) and carbapenems exposure before onset (OR=4.849,95％CI 1.091～21.554) were independent risk factors of neonatal CRKP sepsis (P＜0.05).The mortality rate of CRKP group was higher than the CSKP group (22.9％ vs.5.6％,P=0.036).Conclusion Male,parenteral nutrition and carbapenems exposure before onset were independent risk factors of neonatal CRKP sepsis.CRKP sepsis is critical and has a high mortality rate.Clinicians should monitor drug resistance carefully,follow antibiotics stewardship principles and establish enteral nutrition as soon as possible.
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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 explore the distribution and antimicrobial resistance of pathogens causing lower respiratory tract infection in patients, and provide basis for rational choice of antimicrobial agents in clinic.Methods All bronchoalveolar lavage fluid specimens in a hospital from January 1, 2013 to December 31, 2014 were performed culture, antimicrobial susceptibility testing of isolated strains was performed with Kirby-Bauer method.Results A total of 999 strains were isolated from 7 702 bronchoalveolar lavage fluid specimens, 398 (5.17%), 326 (4.23%), and 275(3.57%) strains were bacteria, fungus, and Mycobacterium respectively.The main bacteria were Pseudomonas aeruginosa(P.aeruginosa, n=97), Acinetobacter baumannii(A.baumannii, n=87), Klebsiella pneumoniae(K.pneumoniae, n=62), Staphylococcus aureus(S.aureus, n=44), and Haemophilus influenzae (n=28);the main fungi were Candida albicans (n=161), Aspergillus fumigatus (n=41), and Aspergillus flavus(n=38);the main Mycobacterium were Mycobacterium tuberculosis(n=271).Antimicrobial susceptibility testing results showed that resistance rates of P.aeruginosa to the commonly used antimicrobial agents (except ticarcillin/clavulanic acid and levofloxacin) were all80.00%, but to the other commonly used antimicrobial agents were 36.84%-60.53%.Among 62 strains of K.pneumoniae, 20 were extended-spectrum β-lactamases(ESBLs)-producing strains.Antimicrobial resistance rates of ESBLs-producing strains were obviously higher than non-ESBLs-producing strains.Among 44 S.aureus strains, 26 were methicillin-resistant S.aureus (MRSA), resistance rate of S.aureus to penicillin was 97.73%, to vancomycin, teicoplanin, and linezolid were all 0, to the other antimicrobial agents were 9.09%-61.36%.Conclusion Bacteria is the major pathogen causing lower respiratory tract infection in hospitalized patients, but fungus and Mycobacterium can not be ignored.Resistance rates of P.aeruginosa to commonly used antimicrobial agents is relatively low, but resistance of A.baumannii is more serious.
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Objective To investigate the distribution and antibiotic resistance of the pathogens isolated from blood of the inpatients in hematology ward.Methods Antimicrobial susceptibility test was carried out using Kirby-Bauer method.The data were analyzed by WHONET 5.6 software.Results Of the 521 microbial isolates collected,gram-negative bacilli accounted for 47.2％,grampositive cocci 45.7％ and fungi (7.1％).The most frequently isolated microorganisms were coagulase negative Staphylococcus (154),E.coli (88),K.pneumoniae (51),P.aeruginosa (39) and Enterococcus spp (34).ESBLs were produced in about 40.4％ of the K.pneumoniae isolates and 63.4％ of the E.coli isolates.At least 90％ of the E.coli isolates were susceptible to imipenem and meropenem,and at least 70％ susceptible to piperacillin-tazobactam.At least 85％ of the K.pneumoniae strains were susceptible to imipenem and meropenem,and at least 70％ susceptible to levofloxacin,piperacillin-tazobactam and cefoperazone-sulbactam.The percentage of the P.aeruginosa susceptible to ciprofloxacin and tobramycin was at least 90％,and higher than 70％ to levofloxacin,meropenem,imipenem,piperacillin-tazobactam,cefepime,and cefoperazone-sulbactam.More than 90％ strains of the coagulase negative Staphylococcus and Enterococcus were susceptible to linezolid and teicoplanin.Overall,82.5％ of the coagulase negative Staphylococcus isolates were resistant to methicillin.Three E.coli isolates and 4 K.pneumoniae isolates were found resistant to carbapenems,and 14 Enterococcus isolates were resistant to vancomycin.Conclusions Gram-negative bacilli are the major pathogens from blood samples in hematology ward,which show high susceptibility to piperacillin-tazobactam and cefoperazone-sulbactam,imipenem and meropenem.The grampositive cocci show high susceptibility to linezolid and teicoplanin.These data are helpful for empirical antimicrobial therapy.
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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 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 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 .
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Objective To investigate distribution and drug resistance of pathogenic bacteria in lower respitatory tract infection. Methods Distribution and drug resistance of pathogenic bacteria in lower respitatory tract infection of patients in ICU and non-ICU of our hospital during 2013 were retrospectivly analyzed. The pathogens were identified by manual methods routinely and those difficult to be identified were analyzed by using the VITEK-2-COMPACT instrument. Antimicrobial susceptibility of these isolates were tested by Kirby-Bauey methods routinely. Results In total, 956 strains were isolated from lower respitatory tract infection of patients in ICU, including 231 strains of gram-positive cocci (24. 2%), 680 strains of gram-negative bacteria (71. 1%), 45 strains of fungi (4. 7%). In patients of non-ICU, 4 464 strains were isolated, including 1 090 strains of gram-positive cocci (24. 4%), 3 226 strains of gram-negative bacteria (72. 3%), and 148 strains of fungi (3. 3%). Staphylococcus aureus, acinetobacter baumannii and pseudomonas aeruginosa were the most frequent isolates in patients of ICU and non-ICU. The overall prevalence of methicillin resistant staphylococcus aureus (MRSA) in staphylococcus aureus was 87. 0%in ICU and 74. 0% in non-ICU. MSSA was sensitive to the most antibiotics ( more than 80. 0% of the strains were sensitive to common antibiotics) except penicillin, erythromycin and clindamycin. MRSA was sensitive to trimethoprim-sulfamethoxazole and fosfomycin (more than 75. 0% of the strains were sensitive to the antibiotics) except for vancomycin, teicoplanin and linezolid. Acinetobacter baumannii was more resistant to the antibiotics (less than 40. 0% of the strains were susceptible to the antibiotics). Pseudomonas aeruginosa from ICU was more resistant to the antibiotics ( less than 50. 0% of the strains were sensitive to the antibiotics) than that from non-ICU. Stenotrophomonas maltophilia was sensitive to trimethoprim-sulfamethoxazole, levofloxacin and minocycline (more than 80. 0% of the strains were sensitive to the antibiotics). Escherichia coli and Klebsiella pneumoniae were sensitive to Piperacillin-tazobactam and Amikacin except for meropenem and imipenem ( more than 80. 0% of the strains were sensitive to the antibiotics) . Conclusion Gram-negative bacteria was the most frequent isolate in lower respitatory tract infection of our hospital during 2013. Staphylococcus aureus, acinetobacter baumannii and pseudomonas aeruginosa were the most frequent isolates in ICU and non-ICU. Resistance to the antibiotics was more common in ICU than in non-ICU. Antibiotics should be prescribed according to bacterial resistance results reasonably in order to prevent the spread of drug-resistant strains.
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Objective To investigate the distribution,variability and antibiotic resistance of the pathogen sisolated from bloodstream infections.Methods The bacterial strains were routinely isolated from blood samples and identified.Brucella trains were identified by PCR and gene sequencing.Antimicrobial susceptibility were routinely tested for these isolates.Results A total of 2 152 strains,excluding coagulase negative Staphylococcus,were isolated from blood specimens during the 5-year period from 2009 through 2013.Gram-positive cocci,gram-negative bacilli and fungi accounted for 35.3% (761/2 152), 57.7% (1 242/2 152)and 6.9% (149/2 152),respectively.The top three gram-positive bacteria were S.aureus,E.faecium and E.faecalis.E.coli,K.pneumoniae,P .aeruginosa,A.baumannii,and Brucella were the most frequently isolated gram-negative bacteria.In 2009,only one Brucella melitensis was isolated,but increased to 50 in 2013 (7.1%),including one strain of Brucella suis .The prevalence of MRSA was 54.1% in S.aureus.No staphylococcal isolate was found resistant to vancomycin or linezolid.More than 60% of the E.faecalis isolates still showed low resistance (70%)except glycopeptides and linezolid.E. coli and K.pneumoniae isolates displayed low resistance rate ( were still the most common pathogens in blood stream infections.Attention should be paid to the increasing prevalence of Brucella in blood stream infections.Various levels of antibiotic resistance are found in the pathogens of blood stream infections.Antibiotics should be prescribed reasonably according to local susceptibility testing data.
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Objective To evaluate the capability of four tests for identification of the in vitro suscepti-bility of tigecycline against Acinetobacter and Enterobacteriaceae isolates.Methods Disk diffusion test was per-formed to detect the sensitivity of 158 Acinetobacter and 339 Enterobacteriaceae isolates to tigecycline.The mini-mum inhibitory concentrations ( MICs) of tigecycline for non-sensitive isolates were detected by using broth dilu-tion method ( BDM) , MIC Test Strip ( MTS) and agar dilution method.The differences with antimicrobial sus-ceptibility among the four different methods were evaluated.Results Tigecycline showed good antibacterial ac-tivity against both non-sensitive Acinetobacter and Enterobacteriaceae isolates with most of the MIC50 values in the sensitivity range of (0.5-2) mg/L and all of the MIC90 values of 4 mg/L.The MIC50 and MIC90 values measured by BDM were respectively 1 mg/L and 4 mg/L.The sensitivity rates presented by the results of BDM were re-spectively 87.1%and 70.2%based on the standards made by Food and Drug Administration (FDA) and Euro-pean Committee on Antimicrobial Susceptibility Testing ( EUCAST) .Agar dilution method indicated that most of the MICs of tigecycline to Acinetobacter and Enterobacteriaceae isolates were two dilutions higher than those de-tected by BDM with essential agreement (EA) rate of 56.5%.Both the very major error (VME) and the major error (ME) values were 0 and the categorical agreement (CA) rate was 46.8%according to the FDA standard.The VME and CA values were 0.8% and 24.2% based on EUCAST standard.Compared with agar dilution method, MTS showed better results in determining the susceptibility of Acinetobacter and Enterobacteriaceae iso-lates to tigecycline with MIC50 and MIC90 values of 1.5 mg/L and 4 mg/L, which was similar to the capability of BDM.Referring to the FDA and EUCAST standards, the sensitivity rates were 83.1% and 21.0%, the CA rates was 81.5%and 29.8%, and the EA rate was 71.8%.Most of the results tested by MTS were one dilution higher than those by BDM.FDA standard showed better correlation than EUCAST standard.Disk diffusion method showed the ME, mE, VME and CA values were respectively 19.4%, 71.8%, 0 and 8.9%according to FDA standard.Conclusion Disk diffusion method, MTS and agar dilution method all showed differences with BDM in susceptibility testing.The capability of MTS was similar to that of BDM.The results evaluated by FDA standard were better than those by EUCAST standard.The in vitro susceptibility of bacteria to tigecycline could be tested by disk diffusion method using FDA standard for evaluation, and confirmed with MTS if isolates were resistance or intermediate strains.The BDM could be performed for further confirmation if necessary.
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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 of clinical strains of K lebsiella spp .isolated from 15 hospitals in China CHINET during 2012 .Methods Kirby-Bauer method and automatic microbiology analysis system were employed to study the antimicrobial resistance . WHONET 5 .6 software was applied for data analysis according to Clinical and Laboratory Standards Institute (CLSI) 2012 breakpoints .Results A total of 9 621 clinical K lebsiella isolates were analyzed ,including 8 772 strains of K . pneumoniae and 804 strains of K . oxytoca . About 54 .9% (5 285/9 621) of the K lebsiella strains were isolated from sputum ,and 16 .3% (1 564/9 621) were isolated from pediatric patients .Antimicrobial susceptibility testing showed that about 8 .9% ,10 .8% and 12 .9% of the strains were resistant to imipenem ,meropenem and ertapenem ,respectively .About 14 .1% and 17 .0% of the strains were resistant to piperacillin-tazobactam and cefoperazone-sulbactam , respectively . Carbapenem-resistant K lebsiella strains were identified from all the 15 hospitals ,including 945 strains of K .pneumoniae and 45 strains of K .oxytoca ,which were resistant to either imipenem ,meropenem or ertapenem .Conclusions The Klebsiella isolates collected from 15 hospitals in China during 2012 are relatively sensitive to carbapenems ,cefoperazone-sulbactam and piperacillin-tazobactam .The prevalence of carbapenem-resistant strains is still increasing in China ,about 10 .3% in 2012 ,and relatively higher in Eastern China .More efforts should be made to control the superbug .
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Objective To investigate the antimicrobial resistance in the clinical strains isolated from Tongji Hospital to the antimicrobial agents commonly used in 2012.Methods Antimicrobial susceptibility was tested by Kirby-Bauer method.The minimum inhibitory concentration (MIC) of penicillin and ceftriaxone for Streptococcus pneumoniae and vancomycin for Staphylococcus spp.were determined by E-test.All data were analyzed by WHONET 5.6 software.Results A total of 8 191 strains were isolated in 2012,including gram-positive bacteria (2 815,34.4%)and gram-negative bacteria (5 376,65.6%). The top five pathogenic bacteria isolated from outpatients were Escheria coli,Pseudomonas aeruginosa,coagulase-negative Staphylococcus (CNS),Klebsiella spp.and Staphylococcus aureus.For the isolates from non-ICU inpatients,the top five were E.coli,S.aureus,Acinetobacter spp.,Klebsiella spp.and P.aeruginosa.For those isolated from ICU patients,the top five were Acinetobacter spp.,S.aureus,P.aeruginosa,Enterococcus spp.and E.coli.The prevalence of MRSA and MRCNS was 58.1% and 64.3%,respectively.Seventeen strains of vancomycin resistant Enterococcus were identified, including 13 strains of E.faecium with VanA and 4 strains of E.gallinarum with VanA and VanC.The percentage of antimicrobial resistance in E.faecium was significantly higher than that in E.faecalis (P<0.05).A total of 94 strains of carbapenem-resistant Enterobacteriaceae were detected.The prevalence of penicillin-non-susceptible S.pneumoniae in children was much higher than that in adults. The prevalence of carbapenem-resistant P.aerugonosa and Acinetobacter spp. was 28.1% and 56.2% respectively.Beta-lactamase was produced in 41.8% of the H.influenzae and 98.6% of the M. catarrhalis isolates. Conclusions The prevalence of multidrug resistant strains has been increasing, especially vancomycin-resistant Enterococcus and carbapenem-resistant Enterobacteriaceae.
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Objective To investigate the resistance of clinical Stenotrophomonas maltophilia isolates from 15 hospitals in several regions of China during 2011.Methods Fifteen repre-sentative general hospitals were involved in this program. Bacterial susceptibility testing was carried out by means of a unified protocol using Kirby-Bauer method and MIC determi-nation.Results were analyzed according to CLSI 2011 break-points.Results Majority (93.3%) of the 1 889 clinical strains of S.maltophilia were isolated from inpatients.On-ly 6.7% of the isolates were from outpatients.About 62.9% of these S .maltophilia strains were isolated from old patients whose age was 60 years or older.Only 8.2% of the strains were from the patients younger than 18 years old.Sputum and re-spiratory tract secretion were the most common specimen source,accounting for 82.6%.Another 4.2% isolates were from blood,abdominal fluid and other sterile body fluids.The percentage of the S .maltophilia strain resistant to trimethoprim-sul-famethoxazole,levofloxacin and minocycline was 16.6%,10.0% and 1.8%,respectively.The strains resistant to cefopera-zone-sulbactam accounted for 19.0%.About 37.1% of the strains isolated from blood or sterile body fluids were resistant to trimethoprim-sulfamethoxazole,significantly higher than the strains from urine or wound specimens (P < 0.01).Conclusions S.maltophilia strains are mainly isolated from inpatients.The most common source is sputum and other respiratory speci-mens.Most of the patients with S.maltophilia isolate are 60 years of age or older.The S.maltophilia strains are constitu-tively resistant to several antibacterial agents,but showed relatively lower resistance to trimethoprim-sulfamethoxazole,levo-floxacin and minocycline.Cefoperazone-sulbactam is still active against these strains.The antimicrobial therapy targeting S. maltophilia infections should be selected cautiously according to the results of antimicrobial resistance surveillance.