scholarly journals A Biological Inventory of Prophages in A. baumannii Genomes Reveal Distinct Distributions in Classes, Length and Genomic Positions

Author(s):  
Belinda Loh ◽  
Jiayuan Chen ◽  
Prasanth Manohar ◽  
Yunsong Yu ◽  
Xiaoting Hua ◽  
...  

AbstractAcinetobacter baumannii is of major clinical importance as the bacterial pathogen often causes hospital acquired infections, further complicated by the high prevalence of antibiotic resistant strains. Aside from natural tolerance to certain antibiotic classes, resistance is often acquired by the exchange of genetic information via conjugation but also by the high natural competence exhibited by A. baumannii. In addition, bacteriophages are able to introduce resistance genes but also toxins and virulence factors via phage mediated transduction. In this work, we analysed the complete genomes of 177 A. baumannii strains for the occurrence of prophages, and analysed their taxonomy, size and positions of insertion. Among all the prophages that were detected, Siphoviridae and Myoviridae were the two most commonly found families, while the average genome size was determined as 3.98 Mbp. Our data shows the wide variation in the number of prophages in A. baumannii genomes and the prevalence of certain prophages within strains that are most “successful” or potentially beneficial to the host. Our study also revealed that only two specific sites of insertion within the genome of the host bacterium are being used, with few exceptions only. Lastly, we analysed the existence of genes that are encoded in the prophages, which confer antimicrobial resistance (AMR). Several phages carry AMR genes, including OXA-23 and NDM-1, illustrating the importance of lysogenic phages in the acquisition of resistance genes.

2020 ◽  
Vol 11 ◽  
Author(s):  
Belinda Loh ◽  
Jiayuan Chen ◽  
Prasanth Manohar ◽  
Yunsong Yu ◽  
Xiaoting Hua ◽  
...  

Acinetobacter baumannii is of major clinical importance as the bacterial pathogen often causes hospital acquired infections, further complicated by the high prevalence of antibiotic resistant strains. Aside from natural tolerance to certain antibiotic classes, resistance is often acquired by the exchange of genetic information via conjugation but also by the high natural competence exhibited by A. baumannii. In addition, bacteriophages are able to introduce resistance genes but also toxins and virulence factors via phage mediated transduction. In this work, we analyzed the complete genomes of 177 A. baumannii strains for the occurrence of prophages, and analyzed their taxonomy, size and positions of insertion. Among all the prophages that were detected, Siphoviridae and Myoviridae were the two most commonly found families, while the average genome size was determined to be approximately 4 Mbp. Our data shows the wide variation in the number of prophages in A. baumannii genomes and the prevalence of certain prophages within strains that are most “successful” or potentially beneficial to the host. Our study also revealed that only two specific sites of insertion within the genome of the host bacterium are being used, with few exceptions only. Lastly, we analyzed the existence of genes that are encoded in the prophages, which may confer antimicrobial resistance (AMR). Several phages carry AMR genes, including OXA-23 and NDM-1, illustrating the importance of lysogenic phages in the acquisition of resistance genes.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
María Dolores Alcántar-Curiel ◽  
Carmen Alejandra Ledezma-Escalante ◽  
Ma Dolores Jarillo-Quijada ◽  
Catalina Gayosso-Vázquez ◽  
Rayo Morfín-Otero ◽  
...  

Klebsiella pneumoniaeis a leading cause of multiple nosocomial infections, some of which are associated with high mortality. The increasing prevalence of antibiotic-resistant strains highlights their clinical importance and how complicated managing treatment can be. In this study, we investigated antimicrobial resistance, cell adherence, and biofilm production of nosocomialK. pneumoniaestrains isolated from surveillance studies in a Mexican tertiary hospital and evaluated the potential association of these phenotypes with endemicity. The great majority of the clones exhibited adhesion to cultured epithelial cells and were strong biofilm producers. A direct relationship between adhesion phenotypes, biofilm production, and endemicity was not always apparent. Biofilm formation and production of ESBL did not appear to be directly associated. Notably, all the endemic strains were multidrug-resistant. This study emphasizes that while endemic strains possess various virulence-associated properties, antimicrobial resistance appears to be a determining factor of their endemicity.


Medicine ◽  
2016 ◽  
Vol 95 (27) ◽  
pp. e4099 ◽  
Author(s):  
Ngai Kien Le ◽  
Wertheim HF ◽  
Phu Dinh Vu ◽  
Dung Thi Khanh Khu ◽  
Hai Thanh Le ◽  
...  

2019 ◽  
Vol 1 (2) ◽  
pp. 18-22
Author(s):  
O A Nazarchuk ◽  
V I Nahaichuk

Introduction. Non-fermenting Gram-negative bacilli are known as one of the most frequent causative agents of hospital-acquired infections. Acinetobacter baumannii, as causative agent of infection complications of different localization, has obtained recently high resistance to anti-biotics and has belonged to ESKAPE group of pathogens. Antimicrobials, recommended for the prophylaxis and therapy of hospital-acquired infections, have been failing in their effectiveness and lead to selection of antibiotic resistant strains of A. baumannii. The aim of this research was to substantiate the way of overcoming of resistance in clinical strains of A. baumannii, by means of synergic antimicrobial activity of antibiotics and antiseptic decamethoxinum®. Material and methods. The research was carried out on 190 clinical strains of A. baumannii, isolated from patients with burn disease during the period 2011–2015. The sensitivity of clinical strains of A. baumannii was determined to such antibiotics as ampicillin/sulbactam, cefoperazone, cefoperazone/sulbactam, meropenem, imipenem, amikacin, ciprofloxacin, gatifloxacin and antiseptic decamethoxinum® (DCM; Registration certificate No UA/14444/01/01 since 24.06.2015. Order of the Ministry of Health of Ukraine No 373). The sensitivity of A. baumannii to antibiotics and DCM was determined by means of disk diffusion test and serial dilution (Order of the Ministry of Health of Ukraine No167 since 05.04.2007; EUCAST expert rules).The study of the influence of antiseptic DCM on the sensitivity of acinetobacteria to antibiotics was studied on 35 clinical strains of A. baumannii, drafted from the general number of isolates enrolled in the research. For this, the sensitivity of A. baumannii to antibiotics in the presence of sub-minimal inhibitory concentrations (subMIC) of DCM was identified. The received experimental data were analyzed by “Statistica 6.0”. Results and discussion. The changes of antibiotic sensitivity profile of A. baumannii for five years were shown. It was found that the sensitivity of A. baumannii to majority of antibiotics, selected for study, decreased significantly. But the only ampicillin/sulbactam was found to have vice versa tendency. We found the rising quantity of antibiotic resistant strains of A. baumannii. At the same time, high resistance of acinetobacteria to fluoroquinolones (ciprofloxacin– 96,1%; gatifloxacin– 95,8%) was found in 2015. The in vitro research of combined activity of DCM antiseptic remedy and early mentioned antibiotics against clinical strains of A. baumannii demonstrated the reveal antibiotic effectiveness. As follows, minimal inhibitory concentrations of antibiotics decreased in 1.5–4 times in the mediums which contained subMIC of DCM. Especially this tendency was found in resistant clinical strains. Conclusion. Under selective influence of antibiotics protected by β-lactamase inhibitors, carbapenems, fluoroquinolones aminoglycosides increase the antibiotic resistance in A. baumannii, causative agents of infectious complications in patients with burn disease. The antiseptic remedy decamethoxinum® helps to improve antibiotic sensitivity in resistant A. baumannii.


Author(s):  
Luhua Zhang ◽  
Xinyue Ma ◽  
Li Luo ◽  
Nan Hu ◽  
Jiayao Duan ◽  
...  

Hospital sewage plays a key role in the dissemination of antibiotic-resistant genes (ARGs) by serving as an environmental antimicrobial resistance reservoir. In this study, we aimed to characterize the cephalosporin- and carbapenem-resistant isolates from hospital sewage and receiving rivers. The results showed that ESBL (blaCTX-M) and carbapenemase genes (blaNDM and blaKPC) were widely detected in a number of different bacterial species. These resistance genes were mainly harbored in Enterobacteriaceae, followed by Acinetobacter and Aeromonas isolates. More attention should be given to these bacteria as important vectors of ARGs in the environment. Furthermore, we showed that the multidrug resistance phenotype was highly prevalent, which was found in 85.5% Enterobacteriaceae and 75% Acinetobacter strains. Notably, the presence of carbapenemase genes in isolates from treated effluents and receiving rivers indicates that the discharges of wastewater treatment plants could be an important source for high-risk resistance genes propagation to the environment. In conclusion, this study shows a high prevalence of ESBL- and carbapenemase-producing bacteria in hospital sewage and receiving rivers in China. These findings have serious implications for human health, and also suggest the need for more efforts to control the dissemination of resistant bacteria from hospital sewage into the environment.


2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Susanne Schjørring ◽  
Karen A. Krogfelt

We assessed horizontal gene transfer between bacteria in the gastrointestinal (GI) tract. During the last decades, the emergence of antibiotic resistant strains and treatment failures of bacterial infections have increased the public awareness of antibiotic usage. The use of broad spectrum antibiotics creates a selective pressure on the bacterial flora, thus increasing the emergence of multiresistant bacteria, which results in a vicious circle of treatments and emergence of new antibiotic resistant bacteria. The human gastrointestinal tract is a massive reservoir of bacteria with a potential for both receiving and transferring antibiotic resistance genes. The increased use of fermented food products and probiotics, as food supplements and health promoting products containing massive amounts of bacteria acting as either donors and/or recipients of antibiotic resistance genes in the human GI tract, also contributes to the emergence of antibiotic resistant strains. This paper deals with the assessment of antibiotic resistance gene transfer occurring in the gut.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 711
Author(s):  
Olga Urbanek ◽  
Alicja Wysocka ◽  
Paweł Nakielski ◽  
Filippo Pierini ◽  
Elżbieta Jagielska ◽  
...  

The spread of antimicrobial resistance requires the development of novel strategies to combat superbugs. Bacteriolytic enzymes (enzybiotics) that selectively eliminate pathogenic bacteria, including resistant strains and biofilms, are attractive alternatives to antibiotics, also as a component of a new generation of antimicrobial wound dressings. AuresinePlus is a novel, engineered enzybiotic effective against Staphylococcus aureus—one of the most common pathogenic bacteria, found in infected wounds with a very high prevalence of antibiotic resistance. We took advantage of its potent lytic activity, selectivity, and safety to prepare a set of biodegradable PLGA/chitosan fibers generated by electrospinning. Our aim was to produce antimicrobial nonwovens to deliver enzybiotics directly to the infected wound and better control its release and activity. Three different methods of enzyme immobilization were tested: physical adsorption on the previously hydrolyzed surface, and covalent bonding formation using N-hydroxysuccinimide/N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide (NHS/EDC) or glutaraldehyde (GA). The supramolecular structure and functional properties analysis revealed that the selected methods resulted in significant development of nanofibers surface topography resulting in an efficient enzybiotic attachment. Both physically adsorbed and covalently bound enzymes (by NHS/EDC method) exhibited prominent antibacterial activity. Here, we present the extensive comparison between methods for the effective attachment of the enzybiotic to the electrospun nonwovens to generate biomaterials effective against antibiotic-resistant strains. Our intention was to present a comprehensive proof-of-concept study for future antimicrobial wound dressing development.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Izabela Korona-Glowniak ◽  
Radoslaw Siwiec ◽  
Anna Malm

Multiple resistance ofStreptococcus pneumoniaeis generally associated with their unique recombination-mediated genetic plasticity and possessing the mobile genetic elements. The aim of our study was to detect antibiotic resistance determinants and conjugative transposons in 138 antibiotic-resistant pneumococcal strains isolated from nasopharynx of healthy young children from Lublin, Poland. These strains resistant to tetracycline and/or to chloramphenicol/erythromycin/clindamycin were tested by PCR using the specific genes as markers. The presence of Tn916family transposons, carryingtet(M) andint/xisTn916, was observed in all of the tested strains. Tn916was detected in 16 strains resistant only to tetracycline. Tn6002and Tn3872-related element were found among 99erm(B)-carrying strains (83.8% and 3.0%, resp.). Eight strains harbouringmef(E) anderm(B) genes were detected, suggesting the presence of Tn2010and Tn2017transposons. Among 101 chloramphenicol-resistant strains, two variants of Tn5252-related transposon were distinguished depending on the presence ofint/xis5252genes specific forcatgene-containing Tn5252(75.2% of strains) orintSp23FST81gene, specific forcat-containing ICESp23FST81 element (24.8% of strains). In 6 strains Tn916-like and Tn5252-like elements formed a Tn5253-like structure. Besides clonal dissemination of resistant strains of pneumococci in the population, horizontal transfer of conjugative transposons is an important factor of the high prevalence of antibiotic resistance.


2021 ◽  
Vol 9 (6) ◽  
pp. 1201
Author(s):  
Niki Hayatgheib ◽  
Ségolène Calvez ◽  
Catherine Fournel ◽  
Lionel Pineau ◽  
Hervé Pouliquen ◽  
...  

This study presents the occurrence and abundance of Aeromonas antibiotic-resistant bacteria (ARB) and genes (ARGs) isolated from water, biofilm and fish in two commercial trout farms before and one week after flumequine treatment. Wild (WT) and non-wild (NWT) strains were determined for quinolones (flumequine, oxolinic acid and enrofloxacin), oxytetracycline (OXY), florfenicol (FFN), trimethoprim-sulfamethoxazole (TMP) and colistin (COL), and pMAR (presumptive multi-resistant) strains were classified. Forty-four ARGs for the mentioned antibiotics, β-lactams and multi-resistance were quantified for 211 isolates. BlaSHV-01, mexF and tetE were the dominant ARGs. A greater occurrence and abundance of tetA2, sul3, floR1, blaSHV-01 and mexF were observed for NWT compared to WT. The occurrence of pMAR and NWT Aeromonas for quinolones, OXY, FFN, TMP, COL and ARGs depended on the Aeromonas origin, antibiotic use and the presence of upstream activities. Our results revealed the impact of a flumequine treatment on Aeromonas present on a fish farm through an increase in NWT and pMAR strains. The link between fish and their environment was shown by the detection of identical ARB and ARGs in the two types of samples. There appears to be a high risk of resistance genes developing and spreading in aquatic environments.


2017 ◽  
Vol 63 (6) ◽  
pp. 508-512 ◽  
Author(s):  
E.V. Starikova ◽  
N.A. Prianichnikov ◽  
E. Zdobnov ◽  
V.M. Govorun

The constant increase of antibiotic-resistant strains of bacteria is caused by extensive uses of antibiotics in medicine and animal breeding. It was suggested that the gut microbiota serves as a reservoir for antibiotics resistance genes that can be carried from symbiotic bacteria to pathogenic ones, in particular, as a result of transduction. In the current study, we have searched for antibiotics resistance genes that are located inside prophages in human gut microbiota using PHASTER prophage predicting tool and CARD antibiotics resistance database. After analysing metagenomic assemblies of eight samples of antibiotic treated patients, lsaE, mdfA and cpxR/cpxA genes were identified inside prophages. The abovementioned genes confer resistance to antimicrobial peptides, pleuromutilin, lincomycins, streptogramins and multidrug resistance. Three (0.46%) of 659 putative prophages predicted in metagenomic assemblies contained antibiotics resistance genes in their sequences.


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