Appendical Perforation by Infection with Extended-Spectrum Beta-Lactamase (ESBL)-Producing <i>Escherichia coli</i>: Case Report

We report the very rare case of a huge appendical abscess with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) as the pathogen. There have been several reports of appendical infections such as appendicitis and appendical abscess caused by ESBL-producing bacteria in adults. The treatment of ESBL-producing E. coli infection is specific, and ESBL-producing bacteria have recently been reported as pathogens associated appendicitis in children. To the best of our knowledge, this is the second report of perforated appendicitis with abscess due to ESBL-producing E. coli. We discuss the diagnostic modalities and treatments for appendical abscess with ESBL-producing E. coli. and propose that the patients with perforated appendicitis and abscess formation due to ESBL-producing E. coli should be administered the antibiotic MEPM within 2 weeks to treat the abscess more effec-tively without producing other multidrug-resistant bacteria.

Detection of Beta-Lactamase and Extended-Spectrum Beta-Lactamase of Pathogens Isolated from Pig and Chicken and Their Antibiotic Susceptibility Test

The antibacterial activity of beta-lactam antibiotics or their combinations with inhibitor sulbactum against non-lactamase- producing strains, lactamase-producing and ESBLs-producing isolates was evaluated with twofold dilution method after pathogens isolated from pigs and chickens were detected, respectively, for beta-lactamase and extended-spectrum beta- lactamases （ESBLs）, The results revealed that most of 43 clinically isolated strains could produce beta-lactamase and 3 strains of shigella isolated from chicken samples produced ESBLs. All of 30 lactamase-producing strains isolated and only one of 16 non-lactamase-producing strains were resistant to amoxicillin and ampicillin. MICs of ampicillin against lactamaseproducing isolates decreased 10-40 and 10-20 times respectively, when it was conbined with sulbactam at ration of 1：2 and 1：4. All clinical isolates were susceptible to third-generation cephalosporins. The MICs of third-generation cephalosporins against lactamase-producing isolates did not change when they were conbined with sulbactam. MICs of ceftiofur and ceftriaxone against ESBLs-producing isolates decreased 2-4 times when they were conbined with sulbactam.

Post-appendectomy pelvic abscess with extended-spectrum beta-lactamase producing Escherichia coli : A case report and review of literature

BACKGROUND Appendicitis, the inflammation of the appendix, is the most common abdominal surgical emergency requiring expedient surgical intervention. Extendedspectrum beta-lactamases(ESBLs) are bacterial enzymes that catalyse the degradation of the betalactam ring of penicillins and cephalosporins(but without carbapenemase activity), leading to resistance of these bacteria to beta-lactam antibiotics. Recent increases in incidence of ESBL-producing bacteria have caused alarm worldwide. Proportion estimates of ESBLEnterobacteriaceae hover around 46% in China, 42% in East Africa, 12% in Germany, and 8% in the United States.CASE SUMMARY The impact of ESBL-producing bacteria on appendiceal abscesses and consequent pelvic abscesses are yet to be examined in depth. A literature review using the search words "appendiceal abscesses" and "ESBL Escherichia coli(E. coli)" revealed very few cases involving ESBL E. coli in any capacity in the context of appendiceal abscesses. This report describes the clinical aspects of a patient with appendicitis whodeveloped a postoperative pelvic abscess infected with ESBL-producing E. coli. In this report, we discuss the risk factors for contracting ESBL E. coli infection in appendicitis and post-appendectomy pelvis abscesses. We also discuss our management approach for postappendectomy ESBL E. coli pelvic abscesses, including drainage, pathogen identification, and pathogen characterisation. When ESBL E. coli is confirmed, carbapenem antibiotics should be promptly administered, as was done efficaciously with this patient. Our report is the first one in a developed country involving ESBL E. coli related surgical complications in association with a routine laparoscopic appendectomy.CONCLUSION Our report is the first involving ESBL E. coli and appendiceal abscesses, and that too consequent to laparoscopic appendectomy.

Diagnostic Validity of Cica Beta Test 1 for the Detection of Extended Spectrum Beta-Lactamase (ESBL) Producing Gram Negative Bacteria by Comparing with Phenotypic Method

Background: Detection of extended spectrum beta lactamase producing bacteria is an important issue in the clinical settings. Objective: The purpose of the present study was to validate the Cica Beta Test 1 for detection of extended spectrum beta-lactamase (ESBL) producing bacteria. Method: This analytical type of cross-sectional study was carried out in the Department of Microbiology and Immunology at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from January 2006 to December 2006 for a period of one (01) year. All the patients presented with the clinical features of urinary tract infection and surgical as well as burn wound infection at any age with both sexes were selected as study population. All bacteria were isolated and identified by their colony morphology, staining characters, pigment production, motility and other relevant biochemical tests. Phenotypic confirmation of ESBLs producing isolates were done by inhibitor potentiated disc diffusion test according to CLSI recommendation. The Cica Beta Test 1 was performed according to the manufacturer’s instructions. Result: A total number of 288 Gram negative bacteria were isolated. Among these isolates Cica Beta test 1 was positive in 97 strains and phenotypic confirmatory test was positive in 89 strains. The test sensitivity of Cica Beta Test 1 was 100% (95% CI 95.9% to 100.0%). Specificity of the test was 96.0% (95% CI 92.2% to 98.2%). The positive predictive value (PPV) and negative predictive value (NPV) were 92.7% (95% CI 84.5% to 95.7%) and 100.0% (95% CI 98.0% to 100.0%) respectively. The accuracy of the test was 97.2% (95% CI 95.1% to 99.1%). Area under ROC curve = 0.980 (95% CI 0.964 to 0.996);p value 0.0001. Conclusion: In conclusion, Cica Beta Test 1 is very high sensitivity and specificity for the detection of ESBL from Gram negative bacteria.

Phenotypic and Genotypic Characterization of Metallo-Beta-Lactamase and Extended-Spectrum Beta-Lactamase among Enterobacteria Isolated at National Public Health Laboratory of Brazzaville

The improper use of antimicrobials against infectious diseases has allowed microorganisms to develop defense mechanisms that give them insensitivity to these agents. All bacteria are concerned by this phenomenon. This work aimed to assess prevalence of beta-lactamase produced by enterobacterial isolates. Then, disc diffusion, double disc synergy test (DDST) and combined disc test (CDT) were respectively used for antimicrobial resistance, detection of Extended-Spectrum Beta-Lactamases (ESBL) and Metallo-Beta-Lactamases (MBL). bla genes were detected by PCR. A total of 132 enterobacterial strains were studied. Resistance to antibiotic families was observed with a greater frequency than 50%. Gentamicin was the least active beta-lactam antibiotic, with a resistance rate of 88%. 40.9% of strains show an ESBL phenotype and 16.6% were MBL. An overall prevalence of 74% (40/54) and respectively rates of 29.6%, 27.7% and 16.7% for blaSHV, blaCTX and blaTEM genes were observed. SHV, CTX, CTX/SHV/TEM, CTX/TEM, SHV/TEM and CTX/SHV were different ESBL genotypes observed. ESBL-producing enterobacteria isolation worried about the future of antimicrobial therapy in the Republic of Congo. This is a public health problem that requires careful monitoring and implementation of a policy of rational antibiotics use.

Activity of Fosfomycin in Extended-Spectrum Beta-Lactamases Producing Klebsiella pneumonae from Hospital Acquired Urinary Tract Infections

Treatment of hospital acquired urinary tract infections (UTIs) caused by extended-spectrum beta-Lactamases producing Klebsiella pneumonae is a major problem. This organism expresses a high level of resistance to many groups of antibiotics. Fosfomycin is an agent which is recommended for treatment of UTIs caused by ESBLs producers. The aim of this study is to determine the sensitivity pattern of ESBLs producing urinary K. pneumonae to antimicrobial agents including fosfomycin in patients of MUHs and determine the prevalence of fosfomycin resistance mediated by plasmid mediated fosfomycin modifying enzymes fosA, fosB and fosA3. Methods: Klebsiella pneumonae urinary isolates were collected from patients with hospital acquired UTIs in Mansoura University Hospitals (MUHs). The susceptibility pattern was determined by Kirby Baur method. Isolates resistant to extended spectrum cephalosporins were tested for ESBLs production by double disc diffusion method. Fosfomycin resistance was determined by broth dilution method. Isolates resistant to fosfomycin were tested for fosA, fosB and fosA3 by PCR. Results: A total of 128 ESBLs producing K. pneumonae isolates were collected. The highest sensitivity was to imipenem (94.5%). The lowest was to trimethoprime-sulphamethoxazole (21.8%). Co-resistance of ESBLs isolates with fosfomycin was 23.2%. Eighteen fosfomycin resistant isolates (18/30) were positive to fosA. Conclusion: ESBLs producing urinary Klebsiella pneumonae express moderate sensitivity to fosfomycin. Resistance is mainly mediated by plasmid mediated fosfomycin modifying enzymes fosA.

Study on the Genotype of Extended-spectrum Beta-lactamases Mediated by Plasmid in Southern China

To investigate the prevalence and genotype of extended spectrum beta-lactamases (ESBLs) mediated by plasmid in Gram-negative bacteria found in southern China, a total of 1184 clinical isolates of non-repetitive strains of Gram-negative bacteria were collected in 2001 from 5 different cities in southern China. The ESBLs-producing isolates were distinguished by means of the phenotype confirmatory test based on the NCCLS criteria and were subjected to plasmid conjugation and electroporation experiments. Those clinical isolates succeeded in plasmid transfers had undergone plasmid conjugation and electro-transformation, plasmid DNA extraction and PstⅠ digest finger-printing analysis, as well as the universal primer PCR amplification of the TEM, SHV, CTX-M, VEB, PER and SFO genes and the DNA sequencing in order to determine the genotypes of ESBLs and their plasmid locations. It was found that the incidence of the ESBLs-producing strains of Gram-negative bacteria was 14.6% (173/1184) with 67 strains of transconjugants and 11 strains of electro-transformants, in which CTX-M-14 type was 33.3% (26/78); CTX-M-3 type was 23.1% (18/78); CTX-M-9 type was 14.1% (11/78); CTX-M-5 type was 6.4% ( 5/78); CTX-M-13 type was 2.6% (2/78); SHV-5 type was 7.7% (6/78); SHV-12 type was 5.1% (4/78), SHV-2a type was 2.6% (2/78) and unidentified type was 5.1% (4/78). 29.5% of the wild strains also carried broad-spectrum beta-lactamases TEM-1 and SHV-1 types. The above mentioned ESBLs genes were located on transferable plasmids with variable sizes (from 35 to 190?kb). The CTX-M type ESBLs was characterized by high-level of resistance to cefotaxime. It concluded that the CTX-M-type was the most prevalent genotype in clinical isolates of Gram-negative bacteria in southern China, and the SHV-type ranks in the second place. TEM-, VEB-, Toho- and PER-types were not found in these isolates.

Extended-spectrum β-lactamase controversies

G.A.Jacoby 教授毕业于美国哈佛医学院,为国际知名的传染病学、微生物学和免疫学专家,曾长期担任美国麻省总医院传染病科医师,现任麻省 Lahey 医学中心传染病实验室主任,中国感染与化疗杂志特邀编委。长期以来 Jacoby 教授对细菌耐药机制有深入研究,尤其对细菌(肺炎克雷伯菌、大肠埃希菌等)产生质粒介导的超广谱β内酰胺酶(ESBL)以及喹诺酮类的耐药机制研究。曾发表多篇有关上述专题的权威性论著。此次本刊特邀 Jacoby 教授撰写有关 ESBL 的新进展,文中阐述目前 ESBLs 除通常所指质粒介导β内酰胺酶中扩大了酶水解的底物谱导致细菌对头孢噻肟、头孢他啶、氨曲南等抗生素耐药外,还包括许多具有不同特点的β内酰胺酶,其中某些酶产自共生菌。除 ESBL 外,AmpC 酶和各种碳青霉烯β内酰胺酶也可导致细菌对上述抗生素耐药,因此临床微生物实验室准确检出和鉴别各种β内酰胺酶,对于临床选用适宜的抗茵药十分重要。美国 CLSI(过去称为 NCCLS)推荐采用两步法(筛选及确证)检测细菌产 ESBL;但有的学者认为测定抗茵药物对细菌的 MIC,如用药后 T>MIC 在50%以上即可达到满意疗效,无需检测细菌是否产 ESBL。目前认为碳青霉烯类抗生素治疗产 ESBL 菌感染的疗效最为满意,但由此可能引起细菌对该类药物耐药,值得关注。采用大剂量头孢吡肟或哌拉西林-三唑巴坦治疗产ESBL 菌感染是否有效尚有争论,临床上对β内酰胺类最为耐药的菌株往往对几乎所有现用抗菌药耐药。黏菌素(或多黏菌素 B)曾成功的用于治疗此种多重耐药菌感染。此外替莫西林(temocillin,一种对β内酰胺酶稳定的青霉素类)与替加环素(tigecvcline,为米诺环素衍生物)体外对产 ESBL 菌有抗菌作用,但尚无临床研究资料。

Distribution of extended-spectrum β-lactamase genes in antibiotic-resistant strains of Pseudomonas aeruginosa obtained from burn patients in Ahvaz, Iran

Objective: To evaluate the drug susceptibility profiles and the frequency of beta-lactamase encoding genes in Pseudomonas aeruginosa (P. aeruginosa) obtained from burn patients. Methods: Totally 93 non-duplicate clinical isolates of P. aeruginosa were recovered from burn patients of Taleghani Burn Hospital of Ahvaz. Antibiotic susceptibility testing was conducted by disk diffusion method according to the CLSI 2017 recommendations. PCR assay was performed by to find beta-lactamase encoding genes. Results: In this study, most clinical specimen was obtained via wound swabs [65 (69.9%)], followed by blood [14 (15.1%)] and biopsy (7 (7.5%))Forty-two (45.16%) patients were male and 51(54.84%) were female. High resistance was observed for most of antibiotics especially for gentamicin and ciprofloxacin (Up to 85%), whereas the highest susceptibility was reported for colistin (100.0%), followed by ceftazidime (66.7%). According to PCR results, 16.1% (15), 9.7% (9) and 14.0% (13) of isolates carried blaDHA, blaVEB and blaGES genes, respectively. It also revealed that the blaVEB gene was found to coexist within 2 isolates (2.2%). Conclusions: Antibacterial resistance is high among P. aeruginosa isolates. Colistin is highly active against multi-drug resistant P. aeruginosa isolates. Antimicrobial susceptibility testing can confine indiscriminate uses of antibiotics and resistance increase, and can improve management of treatment.

Unravelling Antimicrobial Resistance Phenotypes and Carriage of Extended-Spectrum β-Lactamase Genes in Escherichia coli Isolated from Dairy Farms in Kiambu County, Kenya

The use of antibiotics for prophylaxis and growth enhancement in livestock farming is on the increase globally. This practice has led to the emergence and spread of antimicrobial-resistant bacteria in livestock. Only limited research has been done to establish the role of cattle farming in antimicrobial resistance. The current study sought to establish the carriage of multi-drug resistance and extended-spectrum beta-lactamase genes in Escherichia coli from farmers, their cattle, and cattle slurry within Kiambu County. A total of 286 (81%) E. coli isolates were recovered from 352 samples analysed. Antibiotic resistance profiles showed 114 (40%) isolates were resistant to ≥3 antimicrobial classes and were considered multidrug-resistant. Among multidrug-resistant (MDR) E. coli strains, 40 (14%) were resistant to 3 different antimicrobial classes, while 71 (25%) were resistant to between 4 and 7 antibiotic classes. Extended-spectrum β-lactamase resistance was found in 18 isolates: human (n = 14), cattle (n = 2), and environmental (n = 2). Both the blaCTX-M and blaTEM genes were detected in 10 and 15 strains, respectively. Sequence analysis showed that the isolates carried the blaTEM-116 (n = 7), blaTEM-1 (n = 5), and blaCTX-M-15 (n = 8) genes. Genotyping MDR isolates using (GTG) 5 PCR demonstrated that the isolates were not clonal. This data shows antimicrobial resistance profiles and different types of resistance genes in the E. coli population on dairy farms. As a result, more effective, targeted public health policies and measures need to be put in place to control and prevent the emergence and spread of resistant bacteria.

Identification of Klebsiella pneumoniae strains harboring inactive extended-spectrum beta-lactamase antibiotic-resistance genes

Background The extended-spectrum beta-lactamase （ESBL）-producing Klebsiella pneumoniae has increasingly become a major contributor to nosocomial infections and can exhibit multiple antibiotic resistance.Previous studies have focused on the resistance genes in ESBL-producing strains,and the resistance-associated genetic environment of non-ESBL-producing strains has been ignored until now.Here,we investigated the occurrence and characteristics of non-ESBL-producing K.pneumoniae,which potentially carries unexpressed resistance genes.Methods K.pneumoniae strains were collected from five medical institutions in China from February 2010 to August 2013.The VITEK-2 ESBL detection system was used as a primary screen to identify the ESBL-producing phenotype,and the three primary types of ESBL-associated genes （CTX,SHV,and TEM） were detected by polymerase chain reaction （PCR） to confirm the strains presenting with a non-ESBL-producing phenotype.mRNA expression in the non-ESBL-producing strains was further screened by reverse-transcription PCR （RT-PCR） to validate their transcriptional efficiency.Results Out of 224 clinically isolated antibiotic-sensitive K.pneumoniae strains with a non-ESBL-producing phenotype,5 （2.2％） were identified to carry inactivated ESBL blaSHV genes with intact upstream promoter regions and resistance gene sequences.Interestingly,three of the five antibiotic-sensitive K.pneumoniae strains containing ESBL blaSHV genes still exhibited mRNA transcription of blasHv,while the other two exhibited no mRNA transcription.Conclusion These findings suggest that inactivated ESBL genes exist in non-ESBL-producing antibiotic-sensitive K.pneumoniae strains,which have the potential to transform the strain into an ESBL phenotype if an inappropriate application or overdose of antibiotics is implemented during clinical management.

碳青霉烯类非敏感肠杆菌科细菌的β-内酰胺酶检测及耐药性分析

目的：探讨碳青霉烯类非敏感肠杆菌科细菌产碳青霉烯酶、超广谱β-内酰胺酶（ESBLs）及对16种抗菌药物的耐药情况，为临床合理用药提供依据。方法收集2010年1月至2013年12月临床分离的对碳青霉烯类非敏感的肺炎克雷伯菌214株、大肠埃希菌111株，采用改良Hodge试验对碳青霉烯酶进行检测，表型确证试验检测ESBLs，K-B纸片扩散法检测药敏试验。结果214株肺炎克雷伯菌单产碳青霉烯酶的阳性率为57.9%，单产ESBLs为12.6%，同时产ESBLs和碳青霉烯酶为20.6%；111株大肠埃希菌单产碳青霉烯酶的阳性率为54.1%，单产ESBLs为5.4%，同时产ESBLs和碳青霉烯酶为23.4%。试验菌株对临床常用的抗菌药物耐药性严重，耐药率在13.5%-98.1%之间，对米诺环素和替加环素耐药率低。结论对碳青霉烯类非敏感的肺炎克雷伯菌和大肠埃希菌产碳青霉烯酶率高，治疗该类细菌引起的感染可根据病原菌药敏试验结果和患者病情合理选用替加环素或米诺环素，以达到有效控制感染目的。

Health care associated infections, antibiotic resistance and clinical outcome: A surveillance study from Sanandaj, Iran

AIM: To study the antibiotic susceptibility patterns of gram-negative healthcare associated bacterial infections at two tertiary hospitals in the Sanandaj city, Kurdistan Province, Iran.METHODS: From January 2012 to December 2012, all positive cultures from potentially sterile body fluids were gathered. They sent to professor Alborzi clinical microbiology center in Shiraz for further analysis and susceptibility testing. The antibiotic susceptibility was determined using the Kirby-Bauer method(disk diffusiontechnique). The Results were interpreted according to Clinical and Laboratory Standards Institute guidelines against a series of antimicrobials. World Health Organization definitions for Healthcare associated infections were followed.RESULTS: Seven hundred and thirty-two positive cultures were reported from both hospitals. Seventynine isolates/patients fulfilled the study criteria for healthcare associated gram-negative infections. The most frequent bacterial cultures were from the pediatric wards(52%). Serratia marcescens(S. marcescens)(38%) Escherichia coli(E. coli)(19%), Klebsiella pneumoniae(K. pneumoniae)(19%), Acinetobacter baumannii(6%), Enterobacter species(6%), Serratia odorifera(4%) and Pseudomonas species(5%) were the most frequently isolated organisms. The susceptibility pattern of common isolates i.e., S. marcescens, E. coli and K. pneumoniae for commonly used antibiotics were as follows: Ampicillin 3.3%, 6.7%, 20%; gentamicin 73.3%, 73.3%, 46.7%; ceftazidim 80%, 73.3%, 33.3%; cefepim 80%, 86.7%, 46.7%; piperacillin/tazobactam 90%, 66.7%, 86.7%; ciprofloxacin 100%, 73.3%, 86.7%; imipenem 100%, 100%, 100%, respectively. CONCLUSION: The most effective antibiotics against gram-negative healthcare associated infections are imipenem followed by ciprofloxacin. The resistance rate is high against ampicillin and cephalothin. The high mortality rate(46.1%) associated with S. marcescens is alarming.

Molecular Detection and Association of <i>QnrA</i>, <i>QnrB</i>, <i>QnrS</i>and <i>BlaCMY</i>Resistance Genes among Clinical Isolates of <i>Salmonella</i>spp. in Iran

Prevalence of three plasmid-mediated quinolone resistance determinant qnrA, qnrB, qnrS and extended spectrum Cephalosporins determinant blaCMY, among eighty-five isolates of Salmonella spp. collected in the community between 2008 and 2010 was determined by PCR. Not only qnr genes but also bla genes were positive in twenty-four different isolates. PCR assay detected that 22 of 85 (25.8%) Salmonella spp. carried the qnrA, 1 (1.17%) of 85 isolates harbored the qnrB, 1 (1.17%) of them contained the qnrS, 1 (1.17%) isolate carried all the three qnrA, qnrB, qnrS genes, 24 of 85 (28.2%) Salmonella carried blaCMY and 5 (5.88%) isolates carried qnrA and blaCMY. Antimicrobial susceptibility patterns of isolates were as follows: 49 (57.6%) exhibited resistance to Nalidixic acid and none of them to Ciprofloxacin. 33 (38.82%) isolates exhibited resistance to Cephalosporins and 2 (2.35%) of them exhibited ESBL phenotype and 12 (14.1%) isolates resistance to Ampicilin. These results were confirmed by MIC determination test as well. Having detected qnr and bla genes suggested that these genes spread antibiotic resistance among pathogenic bacteria.

Beta-Lactam Antibiotic Resistance among <i>Enterobacter</i>spp. Isolated from Infection in Animals

Nosocomial infections are frequent complications of hospitalization, caused by opportunistic pathogens that gain access to hosts undergoing invasive procedures, such as surgery, intubation, and placement of deep vein lines. Nosocomial infections in animal hospitals can infect other animals, as well as be transmitted to human personnel. Enterobacter is a genus of common gram-negative bacteria, which can be associated with antibiotic resistant hospital infections. Because of an outbreak in antibiotic resistance in the genus, we decided to investigate five years of Enterobacter infections in the Large Animal Services of the Lois Bates Acheson Veterinary Teaching Hospital (LBAVTH) at Oregon State University. The demographics from 37 Enterobacter-infected patients of the LBAVTH were obtained from charts and analyzed. The identified clusters of infections suggested possible patient-environment sources of infection. The environment of the hospital was sampled in an attempt to determine the source of infection. Although Enterobacter was not isolated, three of the collected samples contained bacteria with resistance to third-generation cephalosporins. Enterobacter isolates from six of the 37 patients were further analyzed for presence of specific ESBL resistance genes. All six of the isolates harbored multiple extended-spectrum beta-lactamase genes, i.e., CTX-M-15, TEM-80, SHV-2 and AmpC. In summary, Enterobacter infection in the veterinary hospital was caused by beta-lactam-resistant strains, carrying ESBL-resistant genes. Veterinary hospital personnel should be aware of the potential for transmission, to both humans and animals, of ESBL-gene-containing bacteria.

Characterization of Multidrug Resistant Escherichia coli Isolates Recovered from Humans and Chickens, Trinidad and Tobago

To characterize extended-spectrum beta-lactamase (ESBL) and extra-intestinal pathogenic Escherichia coli (ExPEC) associated virulence genes in E. coli isolates from chickens and humans in Trinidad and Tobago. This cross sectional study was conducted over a three-month period. A total of 471 E. coli isolates;160 from humans treated at a regional tertiary hospital and 311 from chicken caecal samples from “pluck shops” in Trinidad & Tobago were identified using both conventional and molecular microbiological methods. Phenotypic confirmation of ESBL producing E. coli isolates from humans was by Microscan system (Siemens, USA) while the double disk diffusion method was used for the chicken isolates. Polymerase chain reaction (PCR) analysis was used to determine the ESBL and ExPEC-associated virulence genes in representative human isolates and all chicken isolates. From the 311 chicken E. coli isolates, 49.2% (153/311) produced ESBL, while 56.3% (90/160) from humans were ESBL positive. All human and chicken ESBL isolates were 100% susceptible to carbapenems and aminoglycosides antimicrobials. PCR detected 21.1% blaCTX-M, 13.3% blaTEM and 7.8% blaSHV genes among E coli isolates from humans compared to 0.6% blaCTX-M and 48.6% blaTEM genes in chickens. PCR analysis revealed diverse virulence profiles among the isolates. There was a high occurrence rate of ExPEC-asso- ciated virulence genes in E. coli isolates from both humans and chickens. However, the CTX-M-1 genes were most predominant in humans while TEM occurred in chic- ken isolates. The diverse ESBL and virulence associated gene profiles encountered in E. coli isolates from humans and chickens on the surface depicts no similarity or relationships despite occurrence in both cohort groups. Therefore E. coli strains from chickens and humans require further investigation to determine their clonal relatedness or transmission in the country.

Behavior of Antibiotic-Resistant Fecal Coliforms in the Stream of a Sewage Treatment Plant in Tokyo

We are confronting a new threat in the prevalence of antibiotic-resistant bacteria followed by epidemic spread in aquatic environments in metropolitan areas because damage from river floods is increasing remarkably in Japan due to global extreme weather. The sewer penetration rate is about 100% in Tokyo and reclaimed water from sewage treatment plants accounts for over 50% of all water in both the down- and mid-stream areas of local rivers. The water quality of these rivers, which contain microflora, seems to be seriously affected by reclaimed water. In this study, we collected water samples on July 17, 2018 and examined the behavior of antibiotic-resistant fecal coliforms in the stream of a sewage treatment plant in Tokyo. Extended-spectrum β-lactamase (ESBL)-producing fecal coliforms with encoding genes were found;the CTX-M-1, CTX-M-9, TEM, and SHV groups were found to have survived in the final effluent to the river after sterilization with sodium hypochlorite.

Analysis on clinical distribution and drug resistance of Klebsiella pneumoniae isolated for 5 consecutive years

Objective:To analyze the clinical distribution and drug resistance of Klebsiella pneumoniae isolated from patients in a certain hospital and provide a basis for the rational use of antibiotics in the clinical treatment for the infection of Klebsiella pneumoniae.Methods:1,192 strains of Klebsiella pneumoniae isolated from clinical specimens from 2012 to 2016 were collected.The strains were identified by VITEK-2 Compact Microbiological Identification System,and the corresponding results of the antimicrobial susceptibility test were interpreted in accordance with the standards recommended by Clinical and Laboratory Standards Institute(CLSI).Results:1,192 strains of Klebsiella pneumoniae were mainly isolated from sputum(65.6%),and most of them were from Respiratory Medicine Department and Medical Intensive Care Unit of Respiratory Medicine Department(MICU),accounting for 41.4%.Out of 1,192 strains,448 strains were detected to produce extended-spectrum beta-lactamases(ESBLs),accounting for 37.6%.In addition,the detection rates of ESBL-producing Klebsiella pneumoniae for 5 consecutive years showed an increasing trend year by year,and they were higher than the national average values published by China Antimicrobial Resistance Surveillance System(CARSS)in the corresponding period.The drug resistance rate of ESBL-producing Klebsiella pneumoniae was significantly higher than that of non ESBL-producing strains.Conclusions:The infection caused by Klebsiella pneumoniae mainly occurs in the lower respiratory tract,and the drug resistance rates of Klebsiella pneumoniae to antibiotics in the drug susceptibility spectrum are maintained at a high level.Therefore,the rational selection of antibiotics for the clinical treatment of lower respiratory tract infection caused by Klebsiella pneumoniae must be based on the production of ESBLs and the results of antimicrobial susceptibility test.

Genomic insights into the ESBL and MCR-l-producing ST648 Escherichia coli with multi-drug resistance

Polymyxin acts as an ultimate line of refuge against the severe infections by multidrug-resistant Gram- negative pathogens. This conventional idea is challenged dramatically by the recent discovery of mobile colistin resistance gene （mcr-1） is prevalent in food animals and human beings worldwide. More importantly, the mcr-1 gene was found to be co-localized with other antibiotic resistance genes, raising the possibility that super-bugs with pan-drug resistance are emerging. However, little is reported on the genomes of the mcr-l-positive bacterial host reservoirs. Here we report genome sequencing of three human isolates of the mcr-l-positive Escherichia coli （E15004, E15015 and E15017） and define general features through analyses of bacterial comparative genomics. Fur- ther genomic mining together with sequence typing allowed us to elucidate that the MCR-l-carrying E. coli E15017 belongs to the sequence type ST648 and copro- duces extended-spectrum β-1actamase （ESBL）. Given the fact that ST648 has been known to associate New Delhi metallo-β-1actamase 1 or ESBL, with either our results highlighted the possibility of ST648 as an epidemic clone with multidrug resistances.

Zoonotic sources and the spread of antimicrobial resistance from the perspective of low and middle-income countries

Background Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is wide-spread in these countries and is linked to an increased mortality.Apart from human and environmental factors,animal-related drivers of antimicrobial resistance in low-and middle-income countries have special features that differ from high-income countries.The aim of this narrative review is to address the zoonotic sources and the spread of antimicrobial resistance from the perspective of low-and middle-income countries.Main body Contamination with extended-spectrum beta-lactamase(ESBL)-producingEscherichia coli is highest in poultry(Africa:8.9–60%,Asia:53–93%)and there is a risk to import ESBL-producingE.coli through poultry meat in Africa.In aquacultures,the proportion of ESBL-producers amongE.coli can be high(27%)but the overall low quality of published studies limit the general conclusion on the impact of aquacultures on human health.ESBL-producingE.coli colonization of wildlife is 1–9%in bats or 2.5–63%birds.Since most of them are migratory animals,they can disperse antimicrobial resistant bacteria over large distances.So-called‘filth flies’are a relevant vector not only of enteric pathogens but also of antimicrobial resistant bacteria in settings where sanitary systems are poor.In Africa,up to 72.5%of‘filth flies’are colonized with ESBL-producingE.coli,mostly conferred by CTX-M(24.4–100%).While methicillin-resistantStaphylococcus aureus plays a minor role in livestock in Africa,it is frequently found in South America in poultry(27%)or pork(37.5–56.5%)but less common in Asia(poultry:3%,pork:1–16%).Conclusions Interventions to contain the spread of AMR should be tailored to the needs of low-and middle-income countries.These comprise capacity building of diagnostic facilities,surveillance,infection prevention and control in small-scale farming.