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.

OBJECTIVETo assess the association of single nucleotide polymorphisms (SNPs) of the low molecular weight polypeptide (LMP) gene with chronic hepatitis C virus (HCV) infection among ethnic Han population from Yunnan.

METHODSA total of 427 patients with chronic HCV infection and 412 healthy controls were recruited. SNPs rs1351383, rs17587 and rs2127675 from the promoter region of the LMP2 gene and rs2071543 from the promoter region of the LPM7 gene were genotyped using a TaqMan probe. The haplotypes were constructed. Frequencies of various alleles, genotypes and haplotypes of the selected SNPs were calculated, and their association with chronic HCV infection was analyzed.

RESULTSThe frequencies of rs1351383 and rs2127675 alleles of the LMP2 gene, as well as the A-G-A and C-G-G haplotypes of the rs1351383/rs17587/rs2127675 loci, had differed significantly between the two groups (P<0.05).

CONCLUSIONThe C allele of the rs1351383 locus and G allele of the rs2217675 locus of the LMP2 gene may be susceptible factors for chronic HCV infection among ethnic Han people from Yunnan. The A-G-A haplotype of the rs1351383/rs17587/rs2127675 loci may confer a protective effect, while the C-G-G haplotype may be a susceptible factor for chronic HCV infection in this population.

Adult ; Alleles ; Asian Continental Ancestry Group ; genetics ; China ; Female ; Gene Frequency ; genetics ; Genetic Predisposition to Disease ; genetics ; Haplotypes ; genetics ; Hepatitis C ; genetics ; Humans ; Male ; Peptides ; genetics ; Polymorphism, Single Nucleotide ; genetics

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.

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.

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.

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.

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.

Objective To discuss the association of allele polymorphisms SNP-rs1799724(C>T)in the TNF-αand SNP-rs11559013(G>A)in the ALCAM with HCV chronic infection in Han population in Yunnan province. Methods 434 HCV chronic infectious patients and 444 healthy individuals of Han Chinese population in Yunnan province were recruited. Two single nucleotide polymorphisms(SNPs)in the SNP-rs1799724(C>T) of TNF-αgene and SNP-rs11559013(G>A)of ALCAM gene were determined by real-time TaqMan polymerase chain reaction. We evaluated the associations of the two SNPs with HCV chronic infection. Results The distributions of allele and genotype of SNP-rs1799724(C>T)in the TNF-αand SNP-rs11559013(G>A)in the ALCAM between hepatitis C virus(HCV)chronic infectious patients and the healthy controls were not statistically significant(P > 0.05). Conclusion SNP-rs1799724(C>T)in the TNF-αand SNP-rs11559013(G>A) in the ALCAM have no association with HCV chronic infection in the Han population in Yunnan province.

Objective To investigate the effect of resistance nodulation division (RND) efflux pumps on reduced susceptibility to tigecycline in carbapenem-resistant Acinetobacter baumanii.Methods Totally 631 isolates of Acinetobacter baumanii were collected from 16 hospitals in 7 provinces in 2010.Genes oxa-51 and oxa-23 were detected by PCR method,and the ST profiles were determined by multilocus sequence typing (MLST).The disk susceptibility assay was used to determine the inhibition zone diameters of β-lactams,aminoglycosides,macrolides,tetracyclines,carbapenems,tigecycline and polymyxin.The minimum inhibitory concentration (MIC) of tigecycline was determined by E-test in strains with inhibition zone diameters ≤ 12 mm on tigecycline.The expression of operon genes adeB,adeG and adeJ was determined with efflux pump inhibitor NMP (N-methyl-2-pyrrolidone) for detection of efflux pump inhibitor phenotype.The isolates of Acinetobacter baumanii which were resistant both to tigecycline and carbapenems and with the inhibited phenotype of efflux pump inhibitor were collected as the experiment group,the isolates which were susceptible to tigecycline but resistant to carbapenems were collected as the control group,and ATCC 19606 was used as the reference strain.The expressions of adeABC,adeFGH and adeIJK were quantified by q-PCR at the transcriptional level.Genes adeR,adeS and adeL were amplified and sequenced using PCR method to find polymorphic locus and insertion sequences.Results There were 32 isolates of Acinetobacter baumanii with reduced susceptibility to tigecycline and carbapenem-resistant.Eight isolates were with the inhibited phenotype by efflux pump inhibitor.And 4 strains which were susceptible to tigecycline but resistant to carbapenems were selected as the control.The expressions of adeABC in A518,Z1219 and A527 of experiment group were 13-fold,5-fold and 7-fold higher than reference strain ATCC19606,respectively.The expressions of adeFGH and adeIJK were up-regulated slightly in some isolates.Transcript of adeABC was not found in control group strains A207 and A1731,and the expressions of adeABC,adeFGH and adeIJK were not up-regulated in other isolates.The single nucleotide polymorphism (SNP) was detected in adeR (E220K) and adeS (A130D),respectively.ISAab1 insertion sequence was identified in adeS of adeABC-over expressed isolates.No mutation was found in adeL.Conclusion High expression of adeABC pump may play an important role in tigecycline resistance in carbapenem-resistant Acinetobacter baumannii,mainly due to the insertion of ISAba1 sequence in its regulator gene adeS,but other mechanism of tigecycline resistance may not be excluded.

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.