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genetics of antimicrobial resistance

T Koiava, D Gonçalves, J Palmeira, K Arobelidze, M Tediashvili, L Akhvlediani, H Ferreira
Research describing the epidemiology of antibiotic resistant microbes is vital to the proactive development of new antimicrobial agents. In the last years, CTX-M extended-spectrum β-lactamases (ESBLs) have emerged worldwide and have replaced classical TEM and SHV-type ESBLs in many countries. CTX-M-15 is currently the most frequent, with a pandemic distribution, and its rapid spread is facilitated by incorporation of resistance genes in mobile genetic elements. The ESBL is efficacious in Gram-negative bacteria and thus closely associated with nosocomial environments, often colonizing the intestines, particularly in older and dependent patients...
September 2016: Georgian Medical News
Pierre Dehoux, Jean Christophe Marvaud, Amr Abouelleil, Ashlee M Earl, Thierry Lambert, Catherine Dauga
BACKGROUND: Clostridium bolteae and Clostridium clostridioforme, previously included in the complex C. clostridioforme in the group Clostridium XIVa, remain difficult to distinguish by phenotypic methods. These bacteria, prevailing in the human intestinal microbiota, are opportunistic pathogens with various drug susceptibility patterns. In order to better characterize the two species and to obtain information on their antibiotic resistance genes, we analyzed the genomes of six strains of C...
October 21, 2016: BMC Genomics
Sinem Acar, Ece Bulut, Bora Durul, Ilhan Uner, Mehmet Kur, M Dilek Avsaroglu, Hüseyin Avni Kirmaci, Yasar Osman Tel, Fadile Y Zeyrek, Yesim Soyer
192 Food samples (commonly consumed 8 food types), 355 animal samples (animal feces of bovine, ovine, goat and chicken) and 50 samples from clinical human cases in Sanliurfa city, Turkey in a year were collected to determine the Salmonella enterica subsp. enterica mosaic in Turkey. 161 Salmonella isolates represented 17 serotypes, 20 sequence types (STs) and 44 PFGE patterns (PTs). 3 serotypes, S. Enteritidis, S. Typhimurium and S. Kentucky, were recovered from three different hosts. The highest discriminatory power was obtained by PFGE (SID=0...
October 8, 2016: International Journal of Food Microbiology
Li Wang, Lei Liu, Dong Liu, Zhe Yin, Jiao Feng, Defu Zhang, Haihong Fang, Yefeng Qiu, Weijun Chen, Ruisheng Yang, Jinglin Wang, Yunzhi Fa, Dongsheng Zhou
The purpose of this study was to characterize mechanisms of plasmid-mediated antimicrobial resistance in Shigella boydii. S. boydii strain 2246 with resistance to ciprofloxacin, ceftriaxone and azithromycin was isolated from a human case of watery diarrhea in a Chinese public hospital. Resistance in strain 2246 to ceftriaxone and azithromycin was attributable to the presence of blaCTX-M-14, and erm(B) and mph(A), respectively, which were co-located on a multidrug-resistant (MDR) plasmid p2246-CTXM. p2246-CTXM represented a novel IncFII-type MDR plasmid with a very complex chimera structure...
2016: Frontiers in Microbiology
Jinshan Jin, Ying-Hsin Hsieh, Jianmei Cui, Krishna Damera, Chaofeng Dai, Arpana S Chaudhary, Hao Zhang, Hsiuchin Yang, Nannan Cao, Chun Jiang, Martti Vaara, Binghe Wang, Phang C Tai
With the widespread emergence of drug resistance, there is an urgent need to search for new antimicrobials, especially those against Gram-negative bacteria. Along this line, the identification of viable targets is a critical first step. The protein translocase SecA is commonly believed to be an excellent target for the development of broad-spectrum antimicrobials. In recent years, we developed three structural classes of SecA inhibitors that have proven to be very effective against Gram-positive bacteria. However, we have not achieved the same level of success against Gram-negative bacteria, despite the potent inhibition of SecA in enzyme assays by the same inhibitors...
October 18, 2016: ChemMedChem
E Wardal, A Kuch, I Gawryszewska, D Żabicka, W Hryniewicz, E Sadowy
The objective of this study was to investigate the antimicrobial resistance, Tn1546 transposon variability and plasmid diversity among Polish vancomycin-resistant Enterococcus faecium (VREfm) isolates of VanA phenotype in the context of their clonal structure. Two hundred sixteen clinical VREfm isolates collected between 1997 and 2010 were studied by antimicrobial susceptibility testing, MLST, MLVA and detection of IS16, esp Efm, pilA, intA and plasmid-specific genes by PCR. Tn1546 structure was revealed by overlapping PCR and sequencing...
October 17, 2016: European Journal of Clinical Microbiology & Infectious Diseases
Wenyao Chen, Tingzi Fang, Xiujuan Zhou, Daofeng Zhang, Xianming Shi, Chunlei Shi
The wide usage of antibiotics contributes to the increase in the prevalence of antibiotic-resistant Salmonella. Plasmids play a critical role in horizontal transfer of antibiotic resistance markers in Salmonella. This study aimed to screen and characterize plasmid profiles responsible for antibiotic resistance in Salmonella and ultimately to clarify the molecular mechanism of transferable plasmid-mediated antibiotic resistance. A total of 226 Salmonella isolates were examined for antimicrobial susceptibility by a disk diffusion method...
2016: Frontiers in Microbiology
Leise Riber, Mette Burmølle, Martin Alm, Stefan M Milani, Peter Thomsen, Lars H Hansen, Søren J Sørensen
The spread of antimicrobial resistance, usually mediated by horizontal transfer of plasmids, limits the options of treating bacterial infections and thereby poses a crucial human health problem. The disturbance of plasmid stability within bacterial species in clinical environments serves as a novel strategy to reduce the development and dissemination of antibiotic resistance. We tested the ability of irgasan to destabilize plasmids from Escherichia coli K-12 cells when added directly into liquid growth medium at concentrations below levels of marked bacterial growth inhibition, or when released into liquid growth medium from irgasan-impregnated Interpenetrating Polymer Network (IPN) silicone hydrogel objects, a novel technology developed as drug-delivery platform...
October 12, 2016: Plasmid
Maren Seitz, Peter Valentin-Weigand, Jörg Willenborg
Use of antimicrobial agents in veterinary medicine is essential to control infectious diseases, thereby keeping animals healthy and animal products safe for the consumer. On the other hand, development and spread of antimicrobial resistance is of major concern for public health. Streptococcus (S.) suis reflects a typical bacterial pathogen in modern swine production due to its facultative pathogenic nature and wide spread in the pig population. Thus, in the present review we focus on certain current aspects and problems related to antimicrobial use and resistance in S...
October 15, 2016: Current Topics in Microbiology and Immunology
Jennifer Herrmann, Tadeja Lukežič, Angela Kling, Sascha Baumann, Stephan Hüttel, Hrvoje Petković, Rolf Müller
Natural products continue to be a predominant source for new anti-infective agents. Research at the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) and the Helmholtz Centre for Infection Research (HZI) is dedicated to the development of new lead structures against infectious diseases and, in particular, new antibiotics against hard-to-treat and multidrug-resistant bacterial pathogens. In this chapter, we introduce some of the concepts currently being employed in the field of antibiotic discovery...
October 15, 2016: Current Topics in Microbiology and Immunology
Gabriel Cabot, Carla López-Causapé, Alain A Ocampo-Sosa, Lea M Sommer, María Ángeles Domínguez, Laura Zamorano, Carlos Juan, Fe Tubau, Cristina Rodríguez, Bartolomé Moyà, Carmen Peña, Luis Martínez-Martínez, Patrick Plesiat, Antonio Oliver
Whole genome sequencing (WGS) was used for the characterization of the, frequently extensively-drug resistant (XDR), P. aeruginosa high-risk clone ST175. A total of eighteen ST175 isolates recovered from 8 different Spanish hospitals were analyzed; four isolates from four different French hospitals were included for comparison. The typical resistance profile of ST175 included penicillins, cephalosporins, monobactams, carbapenems, aminoglycosides, and fluoroquinolones. In the phylogenetic analysis, the four French isolates clustered together with the two isolates from one of the Spanish regions...
October 10, 2016: Antimicrobial Agents and Chemotherapy
Debkumar Chakraborty, Baljinder Kaur, Karthikeyan Obulisamy, Ammaiyappan Selvam, Jonathan W C Wong
Owing to its flavoring, antimicrobial, antioxidant and anticarcinogenic nature, vanillin is widely used in foods, beverages, perfumes and pharmaceutical products. Ferulic acid (FA) is an important precursor of vanillin which is abundant in cereals like maize, rice and wheat and sugar beet. A major drawback of microbial vanillin production from FA is the degradation and biotransformation of toxic vanillin to other phenolic derivatives. The present study is undertaken to explore microbial vanillin production from FA precursor rice bran by employing vanillin-resistant Pediococcus acidilactici BD16, a natural lactic acid bacteria isolate...
October 13, 2016: Environmental Technology
Mithila Ferdous, Anna M D Kooistra-Smid, Kai Zhou, John W A Rossen, Alexander W Friedrich
Escherichia coli (E.coli) O157 that do not produce Shiga toxin and do not possess flagellar antigen H7 are of diverse H serotypes. In this study, the antibiotic resistance properties, genotype of a set of virulence associated genes and the phylogenetic background of E. coli O157:non-H7 groups were compared. Whole genome sequencing was performed on fourteen O157:non-H7 isolates collected in the STEC-ID-net study. The genomes were compared with E. coli O157 genomes and a typical Enteropathogenic E. coli (tEPEC) genome downloaded from NCBI...
2016: Frontiers in Microbiology
Jing Yu, Kun Tan, Zhihui Rong, Yue Wang, Zhongju Chen, Xuhui Zhu, Li Wu, Li Tan, Wei Xiong, Ziyong Sun, Ling Chen
BACKGROUND: The spread of resistance to carbapenems among Enterobacteriaceae has become a major public health problem in recent years. In this study, we describe an outbreak of Klebsiella pneumoniae in the neonatal ward. First, we aimed to study the drug resistance, genetic relatedness, and transmission mechanism of carbapenem-resistant K. pneumoniae; second, we implemented infection control measures to contain the outbreak. METHODS: We investigated 27 non-repetitive strains isolated from neonates and five strains cultured from around the neonatal ward...
October 12, 2016: BMC Infectious Diseases
Peter Kupferschmied, Tiancong Chai, Pascale Flury, Jochen Blom, Theo H M Smits, Monika Maurhofer, Christoph Keel
Some plant-beneficial pseudomonads can invade and kill pest insects in addition to their ability to protect plants from phytopathogens. We explored the genetic basis of O-polysaccharide (O-PS, O-antigen) biosynthesis in the representative insecticidal strains Pseudomonas protegens CHA0 and Pseudomonas chlororaphis PCL1391 and investigated its role in insect pathogenicity. Both strains produce two distinct forms of O-PS, but differ in the organization of their O-PS biosynthesis clusters. Biosynthesis of the dominant O-PS in both strains depends on a gene cluster similar to the O-specific antigen (OSA) cluster of Pseudomonas aeruginosa...
October 11, 2016: Environmental Microbiology
Giovanni Gherardi, Claudio Palmieri, Emanuela Marini, Arianna Pompilio, Valentina Crocetta, Giovanni Di Bonaventura, Roberta Creti, Bruna Facinelli
This study aimed to retrospectively identify 22Streptococcus bovis clinical strains based on the new taxonomy, as well as to investigate their antibiotic-resistance and clonality. Strains were identified by Phoenix100 system, 16S rRNA sequencing, and two MALDI-TOF MS platforms (Bruker Biotyper, Vitek MS). Antibiotic resistance was determined both phenotypically and genotypically, and clonality was assessed by PFGE. Most of strains (63.6%) were isolated from urine, and diabetes was the most common underlying disease (31...
September 24, 2016: Diagnostic Microbiology and Infectious Disease
Dorota Korsak, Magdalena Szuplewska
A total of 127 Listeria isolates from food and food processing environments, including 75 L. innocua, 49 L. welshimeri, 2 L. seeligeri and 1L. grayi were tested for susceptibility to eight antimicrobials, benzalkonium chloride (BC), cadmium and arsenic. The isolates were also screened for the presence of extrachromosomal genetic elements - plasmids, and their restriction pattern types were determined. All strains were susceptible to ampicillin, ciprofloxacin, erythromycin, gentamicin, rifampicin, trimethoprim and vancomycin...
December 5, 2016: International Journal of Food Microbiology
Débora Farage Knupp Dos Santos, Paula Istvan, Betania Ferraz Quirino, Ricardo Henrique Kruger
Antibiotic resistance has become a major concern for human and animal health, as therapeutic alternatives to treat multidrug-resistant microorganisms are rapidly dwindling. The problem is compounded by low investment in antibiotic research and lack of new effective antimicrobial drugs on the market. Exploring environmental antibiotic resistance genes (ARGs) will help us to better understand bacterial resistance mechanisms, which may be the key to identifying new drug targets. Because most environment-associated microorganisms are not yet cultivable, culture-independent techniques are essential to determine which organisms are present in a given environmental sample and allow the assessment and utilization of the genetic wealth they represent...
October 5, 2016: Microbial Ecology
C Katvoravutthichai, K Boonbumrung, R Tiyawisutsri
Pseudomonas aeruginosa is one of the most important causes of nosocomial infection and it has increasing resistance to many antimicrobial agents. β-lactamase production is the most frequent mechanism for β-lactam resistance in P. aeruginosa. We evaluated the prevalence of β-lactamase genes in P. aeruginosa for classes A, C, and D by polymerase chain reaction, and investigated clonal diversity by pulsed-field gel electrophoresis (PFGE). We used the disk diffusion method to test 118 non-duplicate clinical isolates of P...
September 23, 2016: Genetics and Molecular Research: GMR
Júlia Silveira Vianna, Ivy Bastos Ramis, Daniela Fernandes Ramos, Andrea VON Groll, Pedro Eduardo Almeida da Silva
Background: Helicobacter pylori has a worldwide distribution and is associated with the pathogenesis of various diseases of the digestive system. Treatment to eradicate this microorganism involves the use of a combination of antimicrobials, such as amoxicillin, metronidazole, clarithromycin, and levofloxacin, combined with proton pump inhibitors. Although the current therapy is effective, a high rate of treatment failure has been observed, mainly because of the acquisition of point mutations, one of the major resistance mechanisms developed by H...
October 2016: Arquivos de Gastroenterologia
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