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Meredith S Wright, Stephanie Mountain, Karen Beeri, Mark D Adams
Insertion sequence (IS) elements are found throughout bacterial genomes and contribute to genome variation by interrupting genes or altering gene expression. Few of the more than thirty IS elements described in Acinetobacter baumannii have been characterized for transposition activity or expression effects. A targeted sequencing method, IS-seq, was developed to efficiently map the locations of new insertion events in A. baumannii genomes and was used to identify novel IS sites following growth in the presence of hydrogen peroxide, which causes oxidative stress...
February 13, 2017: Journal of Bacteriology
Prabhu Raj Joshi, Mahesh Acharya, Trishna Kakshapati, Udomluk Leungtongkam, Rapee Thummeepak, Sutthirat Sitthisak
BACKGROUND: Molecular analysis of carbapenem-resistant genes in Acinetobacter baumannii, an emerging pathogen, is less commonly reported from Nepal. In this study we determined the antibiotic susceptibility profile and genetic mechanism of carbapenem resistance in clinical isolates of A. baumannii. METHODS: A. baumannii were isolated from various clinical specimens and identified based on Gram staining, biochemical tests, and PCR amplification of organism specific 16S rRNA and blaOXA-51 genes...
2017: Antimicrobial Resistance and Infection Control
Deepjyoti Paul, Amitabha Bhattacharjee, Birson Ingti, Nargis Alom Choudhury, Anand Prakash Maurya, Debadatta Dhar, Atanu Chakravarty
BACKGROUND: New-Delhi metallo-β-lactamase-7 with higher hydrolytic activity than its ancestor NDM-1 is emerging across the globe including India. In this study, we have investigated the genetic context of blaNDM-7 and alteration in plasmid copy number under concentration gradient carbapenem stress. MATERIALS AND METHODS: Six blaNDM-7 producing Escherichia coli isolates were obtained from Silchar Medical College and Hospital and the co-existence of other β-lactamases and transferability of this resistant determinant was determined by transformation and conjugation assay followed by typing of the plasmid by PBRT method...
January 25, 2017: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
S Datta, S Mitra, P Chattopadhyay, T Som, S Mukherjee, S Basu
To investigate the mobilizable elements associated with bla NDM-1 in Enterobacteriaceae isolated from septicaemic neonates at a NICU in India, during December, 2008-2011. An attempt was also made to understand whether there was a pattern in the temporal acquisition of bla NDM-1 within the unit. Transferability of carbapenem resistance was tested by conjugation and transformation. Plasmid types and addiction systems were analysed. The genetic background of bla NDM-1 and association with class 1 integron were evaluated by PCR mapping...
February 2017: European Journal of Clinical Microbiology & Infectious Diseases
Raquel Girardello, Marina Visconde, Rodrigo Cayô, Regina Célia Bressan Queiroz de Figueiredo, Marcelo Alves da Silva Mori, Nilton Lincopan, Ana Cristina Gales
Polymyxins have become drugs of last resort for treatment of multi-drug resistant (MDR) Gram-negative infections. However, the mechanisms of resistance to this compound have not been completely elucidated. In this study, we evaluated the mechanisms of resistance to this antimicrobial in two A. baumannii clinical isolates, respectively, susceptible (A027) and resistant (A009) to polymyxin B before and after polymyxin B exposure (A027(ind) and A009(ind)). The pmrAB and lpxACD were sequenced and their transcriptional levels were analyzed by qRT-PCR...
January 2017: Diagnostic Microbiology and Infectious Disease
Somdatta Chatterjee, Saswati Datta, Subhasree Roy, Lavanya Ramanan, Anindya Saha, Rajlakshmi Viswanathan, Tapas Som, Sulagna Basu
Carbapenem-resistant determinants and their surrounding genetic structure were studied in Acinetobacter spp. from neonatal sepsis cases collected over 7 years at a tertiary care hospital. Acinetobacter spp. (n = 68) were identified by ARDRA followed by susceptibility tests. Oxacillinases, metallo-β-lactamases (MBLs), extended-spectrum β-lactamases and AmpCs, were detected phenotypically and/or by PCR followed by DNA sequencing. Transconjugants possessing the bla NDM-1(New Delhi metallo-β-lactamase) underwent further analysis for plasmids, integrons and associated genes...
2016: Frontiers in Microbiology
Johanna J Kenyon, Mikhail M Shneider, Sofya N Senchenkova, Alexander S Shashkov, Maria N Siniagina, Sergey Y Malanin, Anastasiya V Popova, Konstantin A Miroshnikov, Ruth M Hall, Yuriy A Knirel
Polymerization of the oligosaccharides (K units) of complex capsular polysaccharides (CPSs) requires a Wzy polymerase, which is usually encoded in the gene cluster that directs K unit synthesis. Here, a gene cluster at the Acinetobacter K locus (KL) that lacks a wzy gene, KL19, was found in Acinetobacter baumannii ST111 isolates 28 and RBH2 recovered from hospitals in the Russian Federation and Australia, respectively. However, these isolates produced long-chain capsule, and a wzy gene was found in a 6.1 kb genomic island (GI) located adjacent to the cpn60 gene...
August 2016: Microbiology
Deepjyoti Paul, Debadatta Dhar, Anand Prakash Maurya, Shweta Mishra, Gauri Dutt Sharma, Atanu Chakravarty, Amitabha Bhattacharjee
BACKGROUND: bla VIM-2 harboring Pseudomonas aeruginosa has been reported worldwide and considered as the most prevalent metallo-β-lactamase after NDM which are found horizontally transferable and mostly associated with integron gene cassettes. The present study investigates the genetic background, transmission dynamics as well as stability of bla VIM-2 in clinical isolates of P. aeruginosa harbor bla NDM-1 as well which were collected from October 2012 to September 2013. METHODS: Two P...
May 6, 2016: Annals of Clinical Microbiology and Antimicrobials
Fangfang Zhang, Lianyan Xie, Xiaoli Wang, Lizhong Han, Xiaokui Guo, Yuxing Ni, Hongping Qu, Jingyong Sun
One hundred and two carbapenem-resistant Enterobacteriaceae (CRE) strains were isolated in a teaching hospital in Shanghai, China from 2012 to 2015. In a follow-up study, four New Delhi metallo-β-lactamase-5 (NDM-5)-producing strains were identified after screening these CRE strains, including 1 Klebsiella pneumoniae strain (RJ01), 1 Proteus mirabilis strain (RJ02), and 2 Escherichia coli strains (RJ03 and RJ04). All K. pneumoniae and E. coli isolates were resistant to carbapenems, third-generation cephalosporins, and piperacillin-tazobactam, but were susceptible to amikacin...
2016: Frontiers in Microbiology
Nabil Karah, Chinmay Kumar Dwibedi, Karin Sjöström, Petra Edquist, Anders Johansson, Sun Nyunt Wai, Bernt Eric Uhlin
Acinetobacter baumannii has emerged as an important opportunistic pathogen equipped with a growing number of antibiotic resistance genes. Our study investigated the molecular epidemiology and antibiotic resistance features of 28 consecutive carbapenem-resistant clinical isolates of A. baumannii collected throughout Sweden in 2012 and 2013. The isolates mainly belonged to clonal complexes (CCs) with an extensive international distribution, such as CC2 (n = 16) and CC25 (n = 7). Resistance to carbapenems was related to blaOXA-23 (20 isolates), blaOXA-24/40-like (6 isolates), blaOXA-467 (1 isolate), and ISAba1-blaOXA-69 (1 isolate)...
January 11, 2016: Antimicrobial Agents and Chemotherapy
Anirban Sarkar, Gururaja P Pazhani, Goutam Chowdhury, Amit Ghosh, Thandavarayan Ramamurthy
A carbapenem resistant Salmonella enterica serovar Senftenberg isolate BCH 2406 was isolated from a diarrheal child attending an outpatient unit of B.C. Roy Hospital in Kolkata, India. This isolate was positive for the bla NDM-1 in the PCR assay, which was confirmed by amplicon sequencing. Except for tetracycline, this isolate was resistant to all the tested antimicrobials. The bla NDM-1 was found to be located on a 146.13-kb mega plasmid pNDM-SAL, which could be conjugally transferred into Escherichia coli and other enteric pathogens such as Vibrio cholerae O1 Ogawa and Shigella flexneri 2a...
2015: Frontiers in Microbiology
Ying-Tsong Chen, L Kristopher Siu, Yu-Kuo Tsai, Fu-Mei Lin, Tse Hsien Koh, Jiun-Han Chen
Bacteria encoding the New Delhi metallo-β-lactamase gene (blaNDM-1) are regarded as superbugs for their resistance to multiple antibiotics. Plasmids encoding blaNDM-1 have been observed to be spreading among gram-negative bacteria around the world. Previous studies have demonstrated that multiple modifications of blaNDM-1-harboring plasmids might contribute to the spread of the gene. In this study, we analyzed blaNDM-1-encoding plasmids from two Klebsiella pneumoniae isolates, DU7433 and DU1301, found to be unrelated by pulsed field gel electrophoresis and multilocus sequencing typing (DU7433: ST14 and DU1301: ST11), and compared them with previously published plasmids...
March 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
Cailin Liu, Shangshang Qin, Hui Xu, Lijuan Xu, Di Zhao, Xuchun Liu, Shaolei Lang, Xianju Feng, Hong-Min Liu
The emergence of New Delhi metallo-β-lactamase 1 (NDM-1) has become established as a major public health threat and represents a new challenge in the treatment of infectious diseases. In this study, we report a high incidence and endemic spread of NDM-1-producing carbapenem-resistant Enterobacter cloacae isolates in Henan province, China. Eight (72.7%) out of eleven non-duplicated carbapenem-resistant E. cloacae isolates collected between June 2011 and May 2013 were identified as NDM-1 positive. The blaNDM-1 gene surrounded by an entire ISAba125 element and a bleomycin resistance gene bleMBL in these isolates were carried by diverse conjugatable plasmids (IncA/C, IncN, IncHI2 and untypeable) ranging from ~55 to ~360 kb...
2015: PloS One
Jiao Feng, Yefeng Qiu, Zhe Yin, Weijun Chen, Huiying Yang, Wenhui Yang, Jie Wang, Yingjie Gao, Dongsheng Zhou
OBJECTIVES: The objective of this study was to characterize the molecular mechanism of coproduction of KPC-2 and NDM-1 in Citrobacter freundii. METHODS: C. freundii strain 112298 was isolated from a human case of septic shock in a Chinese teaching hospital. The major carbapenemase and ESBL genes were detected by PCR. The MIC values were determined by using VITEK 2 and antimicrobial susceptibility was judged by CLSI standards. The resistance plasmid was transferred into Escherichia coli by electroporation, followed by plasmid DNA isolation from the electroporant, and then fully sequenced and compared with closely related plasmids...
November 2015: Journal of Antimicrobial Chemotherapy
Khadidja Khorsi, Yamina Messai, Moufida Hamidi, Houria Ammari, Rabah Bakour
OBJECTIVE: To assess and characterize antibiotic resistance in Acinetobacter baumannii strains recovered from 5 health-care facilities in Algiers. METHODS: Antibiotic susceptibility testing was performed by agar diffusion and agar dilution methods, resistance genes were identified by PCR and sequencing, and molecular typing of isolates was carried out by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). RESULTS: Among 125 tested isolates, 117 (93...
June 2015: Asian Pacific Journal of Tropical Medicine
Tzu-Wen Huang, Tsai-Ling Lauderdale, Tsai-Lien Liao, Ming-Chia Hsu, Feng-Yee Chang, Shan-Chwen Chang, Wei Xin Khong, Oon Tek Ng, Ying-Tsong Chen, Shu-Chen Kuo, Te-Li Chen, Jung-Jung Mu, Shih-Feng Tsai
OBJECTIVES: To investigate the link between two NDM-1-positive Acinetobacter isolates from the same hospital, the plasmid profiles of the isolates were examined. These two isolates were found from a surveillance programme within 3 months from two patients without obvious physical contact or hospitalization time overlap. METHODS: Antimicrobial susceptibility tests, genome sequencing of both isolates and plasmid transfer experiments were performed. A comparative study of similar plasmids was performed using BLAST analysis...
October 2015: Journal of Antimicrobial Chemotherapy
Polyana Silva Pereira, Rodolpho Mattos Albano, Marise Dutra Asensi, Ana Paula D'Alincourt Carvalho-Assef
The emergence of multidrug-resistant Enterobacteriaceae strains producing carbapenemases, such as NDM-1, has become a major public health issue due to a high dissemination capacity and limited treatment options. Here we describe the draft genome of three NDM-1-producing isolates: Providencia rettgeri (CCBH11880), Enterobacter hormaechei subsp. oharae (CCBH10892) and Klebsiella pneumoniae (CCBH13327), isolated in Brazil. Besides blaNDM-1, resistance genes to aminoglycosides [aadA1, aadA2, aac(6')-Ib-cr] and quinolones (qnrA1, qnrB4) were observed which contributed to the multidrug resistance profile...
June 2015: Memórias do Instituto Oswaldo Cruz
Muhammad Kamruzzaman, Jason D Patterson, Shereen Shoma, Andrew N Ginn, Sally R Partridge, Jonathan R Iredell
Comparison of green fluorescent protein expression from outward-facing promoters (POUT) of ISAba1, ISEcp1, and ISAba125 revealed approximate equivalence in strength, intermediate between PCS (strong) and PCWTGN-10 (weak) class 1 integron promoter variants, >30-fold stronger than POUT of ISCR1, and >5 times stronger than Ptac. Consistent with its usual role, PCWTGN-10 produces more mRNA from a "downstream" gfp gene transcriptionally linked to a "usual" PCWTGN-10-associated gene cassette than does POUT of ISAba1...
August 2015: Antimicrobial Agents and Chemotherapy
Zhenhong Chen, Hongxia Li, Jiao Feng, Yuxue Li, Xin Chen, Xuemin Guo, Weijun Chen, Li Wang, Lei Lin, Huiying Yang, Wenhui Yang, Jie Wang, Dongsheng Zhou, Changting Liu, Zhe Yin
A carbapenem-nonsusceptible Enterobacter aerogenes strain named 3-SP was isolated from a human case of pneumonia in a Chinese teaching hospital. NDM-1 carbapenemase is produced by a pNDM-BJ01-like conjugative plasmid designated p3SP-NDM to account for carbapenem resistance of 3-SP. p3SP-NDM was fully sequenced and compared with all publically available pNDM-BJ01-like plasmids. The genetic differences between p3SP-NDM and pNDM-BJ01 include only 18 single nucleotide polymorphisms, a 1 bp deletion and a 706 bp deletion...
2015: Frontiers in Microbiology
Peng Li, Chaojie Yang, Jing Xie, Nan Liu, Houzhao Wang, Ling Zhang, Xu Wang, Yong Wang, Shaofu Qiu, Hongbin Song
BACKGROUND: We have recovered one bla(NDM-1)-harboring bacterial strain, designated as XM1570, from a sputum sample obtained from a fatal case of pneumonia in China. METHODS: Biochemical profiling, 16S rRNA sequencing and antimicrobial susceptibility testing were performed. Conjugation experiments were conducted to determine transmissibility of resistance. Pulsed-field gel electrophoresis and whole genome sequencing were performed to identify strain-specific features...
2015: BMC Infectious Diseases
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