Dissemination of Resistance Integrons and Genes Coding for Blse and Cabapenemases in the Urban Drainage Network in Cote d’Ivoire

Antibiotic resistance has become a major threat to human health worldwide. Environment, particularly the water environment, has long been overlooked as a player in the antibiotic resistance cycle, although its role remains unclear. These can provide an ideal setting for the acquisition and dissemination of antibiotic resistance, as they are frequently affected by anthropogenic activities. The objective of this study was to establish a diffusion map of resistance integrons used as genetic markers of resistance associated with antibiotic resistance conferring genes (ARGs). Total DNA extracts from non-cultivable bacterial communities were used for the analyses. These communities were obtained from wastewater samples from 14 sites upstream and downstream of drainage channels or effluents in the cities of Abidjan, Bouaké, and Yamoussoukro. The results obtained correspond to the number of positives among the treated samples (n = 39). Among the genetic markers of dissemination, class 1 integrons were the most evident in 94.8% of samples in Abidjan (93.3%), Bouaké (100%) and Yamoussoukro (91.6%). Class 2 integrons and class 3 integrons were found respectively in 41% and 51% of all samples. Genes coding for β-lactamases and blaTEM was identified in almost all samples at a rate of 97.4%. A co-presence of the three genes blaTEM, blaSHV and blaCTX-M is also remarkable in the sites of the city of Yamoussoukro. Among the genes coding for carbapenemases, only blaKPC 17.94%, blaNDM 30.76% and blaOXA48 38.46% were detected in the samples.

Multi-drug Resistance and Characteristic of Integrons in Shigella spp.Isolated from China

Objective To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp. Methods Ninety Shigella strains （83 S. flexneri and 7 S. sonnei） were isolated from the stools of patients in China. Susceptibility to 8 antimicrobials was tested for all isolated strains. PCR, RFLP and sequencing analysis of integrons were applied to all of them. Results High prevalence of multi‐drug resistance （95.6%） was identified. Of the isolates 79 （87.8%） carried integrase genes of class 1 integron （3.3%）, class 2 integron （10.0%） or both （74.4%）. No intI3 was detected in the tested isolates. The prevalence of intI2 was significantly higher in isolates with multi‐drug resistance to at least 3 antibiotics than that in isolates with resistance to 2 and less antibiotics （P0.05）. Gene cassettes dfrA17‐aadA5, dfrA12‐orfF‐aadA2 of class 1 integron and dfrA1‐sat1‐aadA1 of class 2 integron were identified. Conclusion The class 2 integron may play a role in the emergence of multi‐drug resistance in Shigella spp.

Prevalence of Carbapenem-Resistant Klebsiella Pneumoniae （CRKP） and the Distribution of Class 1 Integron in Their Strains Isolated from a Hospital in Central China

我们的学习的目的是调查 Carbapenem 抵抗的 Klebsiella pneumoniae (CRKP ) 和班的基因特征的流行的目的在临床的 Klebsiella pneumoniae 拉紧的多药 resistance.Methods 上的 CRKP 的 1 integron 在华中从一所医院的多重部门被收集。CRKP 紧张在 isolates 之中被识别，并且 CRKP 紧张的抗菌素危险性被分析。聚合酶链反应(PCR ) 被采用放大类 1 个 integron 变量区域。integron 基因结构与酶消化和 DNA 定序技术被分析。在班 1 integron 和药抵抗之间的关系被分析完全， 955 Klebsiella pneumoniae 拉紧的 statistically.Results 从医院的改变的地点被孤立，并且(12.3%) 117 作为 CRKP 他们被识别，与在 2013 的8.9%的分离率( 26/292 )，11.3%( 38/336 )在 2014 和16.2%( 53/327 )在 2015 ，哪个表演到年的一个增加的趋势。(52/117 )44.4% 与 ICU 的标本 CRKP 紧张被分开，并且(72/117 )61.5% 从唾沫。超过 95% CRKP 紧张对 ampicillin/sulbactam， aztreonam， imipenem， meropenem， ceftazidme， cefotaxime， cefepime，和 piperacillin 抵抗，当相对低的抵抗的率在 tigecycline (12.8%) 和 colistin (35.9%) 被发现时。班 1 integron 在 77.8% 被检测(91/117 ) CRKP 紧张。CRKP 的班 1 integron 显著地与抗菌素抵抗被相关到 tobramycin， gentamicin 和 amikacin (所有 P < 0.01 ) 。班 1 integron 的可变区域的基因盒子分析证明 aadA2 占 64.8%(59/91 ) ， aacA4-catB8-aadA1 23.1%(21/91 ) ，并且 aadA2-dfrA25 12.1%(11/91 ).Conclusions CRKP 在他们的中国，和大多数在临床的设置有一个增加的趋势对多重抗菌素抵抗。在 CRKP 的班 1 integron 有强壮的能力从环境捕获对 aminoglycosides 抗菌素抵抗的基因，与象最流行的 aadA2 基因。

Antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii from Tehran,Iran

Objective:To investigate antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii(A.baumannii)from Tehran,Iran.Methods:Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute.The presence of integrons was investigated by PCR using specific primers.Results:Among isolated A.baumannii strains,82%were multidrug resistant,27 samples(54%)were resistant to three or more than three antibiotics and 16 samples(32%)showed resistance to two antibiotics.Integrons were detected from 44 of 50 isolates(88%),with classes 1 and 2 being observed in 42%(21/50)and 82%(41/50)of isolates,respectively.Integron-positive A.baumannii isolates showed higher antibiotic resistance than integron-negative isolates and all showed a multidrug-resistant phenotype.Conclusions:Our findings show that classes 1 and 2 integrons,and especially classes 2 integrons are widely disseminated among A.baumannii strains isolated from Tehran and these structures are playing a major role in the acquisition of multidrug resistance in these strains.So monitoring of drug resistance with investigating carriage class 1 and 2 integrons is very important to plan specific infection control measures due to multidrug resistance A.baumannii in Iran hospitals.

Characterization of integrons and novel cassette arrays in bacteria from clinical isloates in China,2000-2014

Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very important role in development of antibiotic resistance. This systematic analysis was based on MEDLINE and EMBASE databases. We summarized the distribution and proportion of different types of gene cassette arrays ofintegrons （including class 1, 2, 3 and atypical class 1 integron） from clinical bacteria isolates in China. Fifty-six literatures were included in this study. Most of the strains were Gram-negative bacteria （94.1%, 7,364/7,822） while only 5.9% strains were Gram- positive bacteria. Class 1 integrons were detected in 54.2% （3956/7295） Gram-negative strains, aadA2 was the most popular gene cassette array detected from 60 Gram-positive bacteria while dfrA 17-aadA5 were detected in 426 Gram- negative bacteria. This study identified 12 novel gene cassette arrays which have not been previously found in any species. All the novel gene cassette arrays were detected from Gram-negative bacteria. A regional characteristic of distribution of integrons was presented in this study. The results highlight a need for continuous surveillance of integrons and provide a guide for future research on integron-mediated bacteria resistance.

Identification and Distribution of the Clinical Isolates of Imipenem-resistant Pseudomonas aeruginosa Carrying Metallo-β-lactamase and/or Class 1 Integron Genes

To investigate the distribution of the genes of two major metallo-β-1actamases （MBL;i.e.,IMP and VIM） and class 1 integrons （intI） in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for blaIMP-1, blaVIM and blaVIM-2 genes. The MBL-positive isolates were further assessed for class 1 integrons by PCRusing specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the blaVIM gene was found in 81.5% （53/65） of all isolates, blaVIM-2 gene was found in only 1 isolate and the intl gene was observed in 45.3% （24/53） of blaVIM-positive isolates. One isolate carried simultaneously both blaIMP-1 and intl genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM β-1actamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P.aeruginosa.

Detection of class 1 integron in Acinetobacter baumannii isolates collected from nine hospitals in Turkey

Objective:To investigate the antibiotic resistance genes inserted into class I and class 2integrons in Acinetobacler baumannii[A.baumannii)isolates obtained from nine different cities in Turkey.Methods:A collection of 281 A.baumannii clinical isolates were collected from nine diferenl state hospitals in Turkey and were confirmed as A.baumannU by conventional biochemical,API testing and bla_(-OXA-51)specific PCR.The isolates were examined by PCR for existence of class I and2 integron gene cassettes.Results:They were characterized by antimicrobial susceptibility testing and the highest resistance rates were determined for piperacillin(90.03%),ciprofloxacin(87.54%),cefepime and trimethoprim/sulfamethoxazole(81.13%).The lowest resistance rates was for cefotaxime(3.55%).class 1 integrons were detected in 6.4%(18/281)of A.baumannii strains and no class 2 integron was detected.The gene casselles of class 1 inlegrons AacCI-AAC(3)l-aadAI,AacCI-aadA1,AAC(3)-I,AAC(3)-I-AAC(3)-I-aadA1,TEM-1.AAC(3)-I-aadA1-AAC(3)-I-AAC(3)-I,AAC(3)-I-AAC(3)-I-AAC(3)-I-aadA1,AAC(3)-I-aadA1,AAC(3)-I-AAC(3)-I,AAC(3)-I-aadA1-AAC(3)-I-aadA1,AAC(3)-I-AAC(3)-I-aadA1-AAC(3)-I-aadA1 were detected in eighteen strains.The aac genes family were most frequently found integrated into the class 1 inlegrons and it was followed by aadA genes and TEM-1 genes.Conclusions:This is an extensive study on the distribulion of class 1 integron among A.baumannii in Turkey.In addition to these,two new alleles were observed.Their percentage rates of similarity to other cassettes are 95%aadA1(TK A18)and 89%,aadA 1(ANKA3).

Integron frequency of Escherichia coli strains from patients with urinary tract infection in Southwest of Iran

Objective: To investigate the frequency of integrase genes intI1, intI2 and intI3 of Escherichia coli strains, and their association with resistance to routinely used antibiotics. Methods: A total of 120 Escherichia coli strains were collected from patients with urinary tract infection in Ahvaz, Southwest of Iran. Antibiotic susceptibility testing was performed. The presence of intI1, intI2, and intI3 genes was determined by polymerase chain reaction. Results: Antibiotic susceptibility testing disclosed the highest resistance rate to ampicillin (91.7%) followed by trimethoprim/sulfamethoxazole (65.8%), and ceftazidime (56.7%). The imipenem susceptibility rate was 91.7%. IntI1 and intI2 were identified in 74 (61.6%) and 8 (6.6%) of Escherichia coli strains, respectively, but intI3 was not found in any isolates. The presence of integrons was significantly associated with resistance to ampicillin, trimethoprim/sulfamethoxazole, ceftazidime, and ciprofloxacin antibiotics (P<0.05). Conclusions: The high resistant Escherichia coli isolates harboring class 1 integrons (intI1) were detected in patients with urinary tract infection in our region. Therefore, preventive strategies are necessary to restrict further dissemination of resistant strains.

Seafood as a Reservoir of Gram-negative Bacteria Carrying Integrons and Antimicrobial Resistance Genes in Japan

PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from local and imported seafood samples collected from retail markets in Hiroshima Prefecture.Class 1 integrons containing gene cassettes encoding resistance to trimethoprim

Characterization of Class 1 Integron Gene Cassettes among Clinical Bacteria Isolated from One Large Hospital in Northern China

The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 integrons containing gene cassettes widely distributed among gram negative clinical isolates was observed. We find that the class 1 integron showed positive correlation with multidrug resistance phenotype of gram negative bacteria. In addition, we find that isolates belonged to one species harbored different types of gene cassette arrays, while same types of gene cassette arrays were observed in different species of isolates. The diversity of gene cassette arrays among the isolates indicated the complexity of multidrug resistance in clinical isolates in northern China.

Antimicrobial resistance patterns and prevalence of integrons in Shigella species isolated from children with diarrhea in southwest Iran

Objective:To investigate the antimicrobial resistance patterns and prevalence of integrons in Shigella species isolated from children with diarrhea in southwest Iran.Methods:In this study,1530 stool samples were collected from children under 15 years with diarrhea referred to teaching hospitals in Ahvaz and Abadan,southwest Iran.Shigella spp.were identified by standard biochemical tests and PCR.The antibiotic resistance pattern of all Shigella isolates was determined by the disk diffusion method and minimum inhibitory concentration(MIC)by E-test.Results:Of 1530 stool samples,91(5.9%,91/1530)were positive for Shigella spp.the most common Shigella isolates were Shigella flexneri 47(51.6%,47/1530).Antibiotic susceptibility tests showed that the highest antibiotic resistance was related to trimethoprimsulfamethoxazole(87.9%,80/91)and ampicillin(86.8%,79/91).Multiplex PCR results revealed that 56%and 86.9%of Shigella isolates carried integron classⅠand integron classⅡgenes,respectively.None of the isolates included the integron classⅢgene.Conclusions:The high prevalence of multi-drug resistance in Shigella isolates in our area increases the concerns about dissemination of the antibiotic-resistant isolates in this bacterium.

Class Ⅰ integron with a novel cassette array in an ESBL-producing multidrug-resistant Klebsiella pneumoniae isolate

Objective： To analyze the molecular mechanism of integron mediated mulfi-resistanc, e in an ESBL-producing K. pneumoniae NJ 12 isolate. Methods： Susceptibility test was carried out by Kirby-Bauer method. Class Ⅰ, Ⅱ and Ⅲ integrons were detected by integrase gene PCR with primers that annealed to conserved regions of integron-encoded integrase genes intll, intl2 and intl3. The variable region of integron was amplified by integron PCR with primers that targeted the conserved flanking regions, and the product was sequenced. Six aminoglycoside modifying-enzyme genes, including ant（2＂）-Ⅰ, ant（3＂）- Ⅰ, aac（3）- Ⅰ, aac（3）-Ⅱ, aac （6＇）-Ⅰ, and aac（6＇）-Ⅱ , were detected. Results： K. pneumoniae NJ 12 was resistant to nine antibiotics, including piperacillin, ampicillin, cefuroxime, ceftazidime, cefotaxime, aztreonam, streptomycin, gentamicin and amikacin. This isolate was shown that there was positive with class Ⅰ integron, ant（2＂）- Ⅰ , ant（3＂）- Ⅰ , aac（3）-Ⅱ and aac（6＇）- Ⅰ modifying-enzyme genes. Neither class Ⅱ nor Ⅲ integron was detected; DNA sequencing of the fragment amplified by integron PCR revealed a novel cassette array aadR-cat-blaoxa-10/ aadA1. Conclusion： Class I integron with a novel cassette array in an ESBL-producing multidrug-resistant K. pneumon/ae NJ 12 isolate was reported from Nanjing area of China, with the GenBank accession number DQ141319.

Characterisation of Class 1 Integron among <i>Escherichia coli</i>Isolated from Mansoura University Hospitals in Egypt

Extensive use of antibacterials in clinical practice has been associated with increasing frequency of multi-resistant E. coli strains. Genetic elements such as Class 1 integrons have an important role in resistance development. In the current study, a total of 84 E. coli clinical isolates from Mansoura hospitals patients in Egypt were screened for antibacterial susceptibility against 12 different antibacterials. High resistance rates were identified for Ampicillin (92.9%) and sulfamethoxazole/ trimethoprim (84.5%). Class 1 integron was investigated in E. coli isolates by PCR. As a result, Class 1 integron was identified in 51.2% of these isolates. The contents of amplified integron varriable regions, were digested by Alu I restriction endonuclease. Cluster analysis of Class 1 integron digested varriable regions revealed that RFLP digested fragments generated could be classified into 9 different patterns, namely A, B, C, D, E, F, G, H and I. The most prevalent genotype was identifed in Group D. PCR and sequencing were used for detection of antimicrobial resistance genes harbored in integrons of Group D. As a result, main phylogenetic group identified harbored integron cassette carrying resistance gene for two antimicrobial groups namely aminoglycoside and trimethoprim. Multiresistance profiles in Group D exhibited association between antimicrobial resistance and integron presence. These findings suggest that the strategy for treatment of patients with E. coli infections needs to be revised. Furthermore, the high prevalence of Class 1 integron carrying gene confirms the importance of integron-mediated antimicrobial gene cassettes.

Identification and characterization of integron mediated antibiotic resistance in pentachlorophenol degrading bacterium isolated from the chemostat

A bacterial consortium was developed by continuous enrichment of microbial population isolated from sediment core of pulp and paper mill effluent in mineral salts medium（MSM） supplemented with pentachlorophenol（PCP） as sole source of carbon and energy in the chemostat.The consortia contained three bacterial strains.They were identified as Escherichia coli,Pseudomonas aeruginosa and Acinetobacter sp.by 16S rRNA gene sequence analysis.Acinetobacter sp.readily degraded PCP through the formation of tetrachloro-p-hydroquinone（TecH）,2-chloro-1,4-benzenediol and products of ortho ring cleavage detected by gas chromatograph/mass spectrometer（GC-MS）.Out of the three acclimated PCP degrading bacterial strains only one strain,Acinetobacter sp.showed the presence of integron gene cassette as a marker of its stability and antibiotic resistance.The strain possessed a 4.17 kb amplicon with 22 ORF＇s.The plasmid isolated from the Acinetobacter sp.was subjected to shotgun cloning through restriction digestion by BamHI,HindIII and SalI,ligated to pUC19 vector and transformed into E.coli XLBlue1α,and finally selected on MSM containing PCP as sole source of carbon and energy with ampicillin as antibiotic marker.DNA sequence analysis of recombinant clones indicated homology with integron gene cassette and multiple antibiotic resistance genes.

<i>Escherichia coli</i>Harbouring Resistance Genes, Virulence Genes and Integron 1 Isolated from Athi River in Kenya

Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of resistance, virulence and integron 1 genes. A cross-sectional study was carried out where 318 water samples were collected (53 from each site) and from the samples, 318 E. coli isolates were analysed for resistance genes, virulence genes and integron 1 using Polymerase Chain Reaction. 22% of the isolates had blaTEM, 33% had blaCTX-M and 28% had blaCMY. Prevalence of typical Enteropathogenic E. coli strains (carrying both eae and bfp genes) was 5% while the prevalence of atypical Enteropathogenic E. coli (carying only eae) was 1.8%. The prevalence of Enteroaggregative E. coli carrying the aggr genes was 11%. The prevalence of Enterotoxigenic E. coli encoding only lt toxin was 16 (5%) and while those carrying only st toxin was 6.9%. The prevalence of Enteroinvasive E. coli strains encoding as IpaH was 5% while that of strains, adherent invasive E. coli, carrying adherent invasive gene inv was 8.7%. 36% isolates were positive for class 1 integrons which were mostly isolated near the sewage effluent from waste treatment plant. Anthropogenic activities and close proximity to sewage treatment plant were found to play a key role in pollution of water body and accumulation of resistance and virulence genes. These results suggest that waste treatment plant may act as reservoir of resistance, virulence and integron 1 genes and is a potential risk to human and animal health in the region.

Screening of Class 1 and Class 2 Integrons in Clinical Isolates of Pseudomonas aeruginosa Collected from Seven Hospitals in Turkey:A Multicenter Study

Pseudomonas aeruginosa is one of the leading nosocomial pathogens worldwide, and their infections are difficult to treat due to acquired resistance to many antibiotics. This study aimed to detect class 1 and 2 integrons and antibiotic susceptibility of clinical isolates of P. aeruginosa. Two hundred and five P. aeruginosa strains were collected from the seven general state hospitals in Turkey. They were characterized by antimicrobial susceptibility testing, screened for class 1 and class 2 integrons, and evaluated for the association between antibiotic resistance phenotypes and the presence of integrons. intI gene was amplified in 10 isolates (4.87%) by PCR and in seven isolates of them (70%) were found different gene cassettes. The aadA gene integrated into the class 1 integrons was most frequently found and it was followed by aac genes and blaOXA family genes. Sequence analysis of variable regions of the class 1 integrons showed five gene cassette arrays;aadA1(99%), aac(3)-Id(82%)-orf-aac(3”)-Ia(99%), aac(3)-Ie(83%)-blaoxa10(100%)- aadA1 (100%), aadA6(99%, 100%), aac(6’)-I(97%)-orf-aadA2(99%). No class 2 integron was detected. This study is the first multicenter study for class 1 integrons and it indicates the low rate of presence of class 1 gene cassette in P. aeruginosa.

Correlation of the antiseptic resistance in Acinetobacter baumannii and the antiseptic resistance gene qacEΔ1 located in classⅠintegron

In the past decade, uses of antiseptics and disinfectants in hospitals and other health care centers are rather common, but the chance to develop resistance to antiseptics and disinfectants is also increased. Acinetobacter baumannii is one of the opportunistic bacteria involving in the nosocomial infection . In the present study, the correlation of the antiseptic resistance in A . baumannii and the antiseptic resistance gene qacEΔ1 was investigated by means of determination of MICs. Meanwhile, the MICs of glutaraldehyde, chlorhexidine, benzalkonium bromide, iodophor and trichloroisocyanurate to 80 clinical isolates of A. baumannii were detected by tube dilution assay and the resistance genes intI1 and qacEΔ1 in these isolates were amplified by PCR and verified by DNA sequencer. It was found that the MIC50 for these 5 antiseptics tested were 32, 8, 8, 4 and 1μg/ml respectively, and the detection rates of intI1 and qacEΔ1 gene were 60.0% and 77.6% respectively. In addition, 55% of the 80 isolates simultaneously possessed both intll and qacEΔ1 gene, and the percentage of antiseptic resistance of A . baumannii carring both genes to benzalkonium bromide were higher than that without these two genes, however, there was no significant difference between intll and qacEΔ1 gene. The result in bactericidal efficiency assay indicated that chlorhexidine could still produce rapid and strong bactericidal effect at concentration of 1 MIC after 10 min exposure. These results suggest that the antiseptic resistance of A . baumannii to various antiseptics is correlated with the presence of the antiseptic resistance genes qacEΔ1 in bacteria, thus warning that the increase of the antiseptic resistance should not be ignored and the relative high concentration or prolonged application time is required to achieve a sufficient bactericidal effect.

34株鸭疫里默氏杆菌的分离鉴定及部分耐药基因调查分析

为更好的指导养殖场鸭疫里默氏杆菌病临床用药以及探究该菌多重耐药机制,本研究对安徽地区患病鸭采样、细菌分离鉴定后,进行生化鉴定、药敏试验,再根据药敏结果进行氨基糖苷类耐药基因以及Ⅰ类整合子鉴定。药敏试验结果表明该地区34株鸭疫里默氏杆菌分离株对头孢拉定、头孢曲松、氟苯尼考、大观霉素、磺胺异恶唑等抗生素较敏感,对卡那霉素、庆大霉素、丁胺卡那、链霉素、阿奇霉素等抗生素均有较强的耐药性;其中有97%的菌株存在多重耐药现象,最高可耐19种抗生素。15种氨基糖苷类耐药基因鉴定结果表明aac(6')Ⅰb基因、aac(6')Ⅱ基因、rmtC基因、aph(3')Ⅱa基因检出率分别为94.1%(32/34)、82.4%(28/34)、73.5%(25/34)、70.6%(24/34),其余基因均未检测到;同时34株分离株均携带Ⅰ类整合子,大小为1 kb,其基因盒种类为aadA1(链霉素耐药基因);其氨基糖苷类耐药表型和耐药基因符合率大于69%。因此,安徽地区鸭疫里默氏杆菌分离株多重耐药性严重,需加强对抗生素的用药规范性,特别要注意氨基糖苷类药物使用。

Investigation of integrons/cassettes in antimicrobial-resistant Escherichia coli isolated from food animals in China

In this study,326 Escherichia coli isolates from food animals collected during the last four decades in China were characterized using antimicrobial susceptibility testing and screening for integrons/cassettes.Minimum inhibitory concentration(MIC) testing indicated that the antimicrobial resistance of E.coli has increased since the 1970s.The findings of this study present a warning to veterinary practitioners about the excessive use of antimicrobials,and suggest the necessity for surveillance and control of antimicrobial resistance in veterinary clinical medicine in China.

阴沟肠杆菌的耐药性分析及氨基糖苷类相关耐药基因的初步研究

目的分析阴沟肠杆菌的耐药性,探讨氨基糖苷类相关耐药基因情况。方法应用PCR技术扩增阴沟肠杆菌的6种AMEs基因,2种16SrRNA甲基化酶基因和I类整合子基因(intI),分析这些基因与氨基糖苷类抗生素耐药的相关性。结果本院阴沟肠杆菌除对一代头孢、个别β-内酰胺酶抗生素耐药率较高外,其他抗生素耐药情况较好。9株氨基糖苷类耐药株共检出AMEs基因5种,其中aac(6')-Ib检出率最高,为66.67%,未检出aac3-Ⅲ基因;armA检出率44.44%;intI检出率77.78%。阴沟肠杆菌的耐药表型和基因型的相符合率为84.24%。结论本院阴沟肠杆菌耐药情况尚可,氨基糖苷类药物耐药性与AMEs基因密切相关,说明临床仍需加强对抗生素的监测与合理应用。