antibiotic resistance and biofilm formation

In recent years the antimicrobial peptides (AMPs) have been prospected and designed as new alternatives to conventional antibiotics. Indeed, AMPs have presented great potential toward pathogenic bacterial strains by means of complex mechanisms of action. However, reports have increasingly emerged regarding the mechanisms by which bacteria resist AMP administration. In this context, we performed a comparative proteomic study by using the total bacterial lysate of magainin I-susceptible and -resistant E. coli strains...

The treatment of superficial wound infections with local antibiotics is considered to be problematic as it is accompanied by an increased risk of resistance development and ineffectiveness in deeper regions. On the contrary, the local application of antibiotics is useful in arthroplasty and necessary if implants are utilized. The reason for this is the prevention of a rapid biofilm formation on foreign implants and a resulting infection may remain undiscovered until it becomes chronic. Apart from exogenous material, necrotic tissue (e...

Efflux transporters have been implicated in regulating bacterial virulence properties such as resistance to antibiotics, biofilm formation and colonization. The pathogenicity of Streptococcus mutans, the primary etiologic agent of human dental caries, relies on the bacterium's ability to form biofilms on tooth surface. However, the studies on efflux transporters in S. mutans are scare and the function of these transporters remained to be clarified. In this study, we identified an efflux transporter (LmrB) in S...

Bacteria growing within biofilms are protected from antibiotics and the immune system. Within these structures, horizontal transfer of genes encoding virulence factors, and promoting antibiotic resistance occurs, making biofilms an extremely important aspect of pneumococcal colonization and persistence. Identifying environmental cues that contribute to the formation of biofilms is critical to understanding pneumococcal colonization and infection. Iron has been shown to be essential for the formation of pneumococcal biofilms; however, the role of other physiologically important metals such as copper, zinc, and manganese has been largely neglected...

Pseudomonas aeruginosa is a formidable pathogen that is responsible for a diverse spectrum of human infectious diseases, resulting in considerable annual mortality rates. Because of biofilm formation and its ability of rapidly acquires of resistance to many antibiotics, P. aeruginosa related infections are difficult to treat, and therefore, developing an effective vaccine is the most promising method for combating infection. In the present study, we designed a novel trivalent vaccine, PcrV28-294-OprI25-83-Hcp11-162 (POH), and evaluated its protective efficacy in murine pneumonia and burn models...

In chronic respiratory disease the formation of dense, 3-dimensional 'micro colonies' by Pseudomonas aeruginosa within the airway plays an important role in contributing to resistance to treatment. An in vitro biofilm model of pseudomonal microcolony formation using artificial sputum (AS) medium was established to study the effects of low molecular weight alginate oligomers (OligoG CF-5/20) on pseudomonal growth, microcolony formation and the efficacy of colistin. The studies employed clinical cystic fibrosis (CF) isolates (n=3) and reference non-mucoid and mucoid multi-drug resistant (MDR) CF isolates (n=7)...

BACKGROUND: We sought to determine the incidence of bacterial biofilm-based catheter-associated urinary tract infections, identify variables affecting biofilm formation, and identify etiologic bacterial pathogens and antibiotic-resistance patterns associated with biofilm-based catheter-associated urinary tract infections (CAUTIs) in our setup. METHODS: Patients who developed at least 2 symptoms of urinary tract infection after at least 2 days of indwelling urinary catheters were included...

Actinobacillus pleuropneumoniae is the causative agent of the highly contagious and deadly respiratory infection porcine pleuropneumonia, resulting in serious losses to the pig industry worldwide. Alternative to antibiotics are urgently needed due to the serious increase in antimicrobial resistance. Thymol is a monoterpene phenol and efficiently kills a variety of bacteria. This study found that thymol has strong bactericidal effects on the A. pleuropneumoniae 5b serotype strain, an epidemic strain in China...

Staphylococcus aureus (S. aureus) is a Gram-positive pathogen and forms biofilm easily. Bacteria inside biofilms display an increased resistance to antibiotics and disinfectants. The objective of the current study was to assess the antimicrobial activities of emodin, 1,2,8-trihydroxy-6-methylanthraquinone, an anthraquinone derivative isolated from Polygonum cuspidatum and Rheum palmatum, against S. aureus CMCC26003 grown in planktonic and biofilm cultures in vitro. In addition, a possible synergistic effect between emodin and berberine chloride was evaluated...

OBJECTIVE: The genus Roseomonas comprises a group of pink-pigmented, slow-growing, aerobic, non-fermentative Gram-negative bacteria, which have been isolated from environmental sources such as water and soil, but are also associated with human infections. In the study presented here, Roseomonas mucosa was identified for the first time as part of the endodontic microbiota of an infected root canal and characterised in respect to growth, antibiotic susceptibility and biofilm formation. RESULTS: The isolated R...

Diverse organisms secrete redox-active antibiotics, which can be used as extracellular electron shuttles by resistant microbes. Shuttle-mediated metabolism can support survival when substrates are available not locally but rather at a distance. Such conditions arise in multicellular communities, where the formation of chemical gradients leads to resource limitation for cells at depth. In the pathogenic bacterium Pseudomonas aeruginosa PA14, antibiotics called phenazines act as oxidants to balance the intracellular redox state of cells in anoxic biofilm subzones...

Pseudomonas aeruginosa can cause complicated urinary tract infections, particularly in people with catheters, which can lead to pyelonephritis. Whilst some subgroups appear more susceptible to infection, such as the elderly and women, the contribution of other host factors and bacterial virulence factors to successful infection remains relatively understudied. In this review, we explore the potential role of P. aeruginosa virulence factors including phenazines, quorum sensing, biofilm formation, and siderophores along with host factors such as Tamm-Horsfall protein, osmotic stress and iron specifically on establishment of successful infection in the urinary niche...

Bacterial biofilms form when bacteria adhere to a surface and produce an exopolysaccharide matrix ( Costerton Science 1999 , 284 , 1318 ; Davies Science 1998 , 280 , 295 ; Flemming Nat. Rev. Microbiol. 2010 , 8 , 623 ). Because biofilms are resistant to antibiotics, they are problematic in many aspects of human health and welfare, causing, for instance, persistent fouling of medical implants such as catheters and artificial joints ( Brunetto Chimia 2008 , 62 , 249 ). They are responsible for chronic infections in the lungs of cystic fibrosis patients and in open wounds, such as those associated with burns and diabetes...

Pseudomonas aeruginosa is a Gram-negative bacterium, which causes opportunistic infections in immuno-compromised individuals. Due to its multiple resistances toward antibiotics, the development of new drugs is required. Interfering with Quorum Sensing (QS), a cell-to-cell communication system, has shown to be highly efficient in reducing P. aeruginosa pathogenicity. One of its QS systems employs Pseudomonas Quinolone Signal (PQS) and 4-hydroxy-2-heptylquinoline (HHQ) as signal molecules. Both activate the transcriptional regulator MvfR (Multiple Virulence Factor Regulator), also called PqsR, driving the production of QS molecules as well as toxins and biofilm formation...

The antibiotic era is on the verge of a profound change and facing a ground shaking crisis. The frequent failures of antibiotic treatments are often associated with biofilm formation, which is responsible for chronic infections, exacerbation as well as reinfection. So far, albeit the large number of valuable strategies employed to combat biofilm formation, little success has been recorded. In this work, we propose a simple approach, based on hydrophobic ionic complexation with the bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), to enhance anti-biofilm activity of well-known antibiotics, namely kanamycin (K), amikacin (A) and vancomycin (V)...

There is an increasing trend in the food industry on the Listeria monocytogenes biofilm formation and inhibition. This is attributed to its easy survival on contact surfaces, resistance to disinfectants or antibiotics and growth under the stringent condition used for food processing and preservation thereby leading to food contamination products by direct or indirect exposure. Though, there is a lack of conclusive evidences about the mechanism of biofilm formation, in this review, the concept of biofilm formation and various chemical, physical, and green technology approaches to prevent or control the biofilm formed is discussed...

Infections caused by commensal organisms by changing to infectious life style generate much challenge to the current treatment strategies. Coagulase Negative Staphylococci (CoNS) are one of them, with their coexisting biofilm forming and multiple antibiotic resistance properties form important agents of nosocomial infection. To evaluate species distribution, biofilm formation, and antibiogram, CoNS isolates from various clinical samples were isolated. The presence of biofilm and associated genes icaAB, aap, atlE, embp, bhp, and fbe in CoNS was screened by PCR...

Treatment of urinary tract infections is today a challenge due to the increasing prevalence of multidrug-resistant ESBL-producing uropathogenic Escherichia coli (UPEC). There is an urgent need for new treatment strategies for multidrug-resistant UPEC and preferably with targets that have low potential for development of resistance. Carbon monoxide-releasing molecules (CORMs) are novel and potent antibacterial agents. The present study examines the transcriptomic targets of CORM-2 in a multidrug-resistant ESBL-producing UPEC isolate in response to a single exposure to CORM-2 and after repeated exposure to CORM-2...

Pseudomonas aeruginosa is an opportunistic pathogen that can be very hard to treat because of high resistance to different antibiotics and alternative treatment regimens are greatly needed. An alternative or a complement to traditional antibiotic is to inhibit virulence of the bacteria. The salicylidene acylhydrazide, INP0341, belongs to a class of compounds that has previously been shown to inhibit virulence in a number of Gram-negative bacteria. In this study, the virulence blocking effect of INP0341 on P...

The YmdB protein, an inhibitor of biofilm formation and an inducer of apramycin susceptibility in Escherichia coli (E. coli), is part of a putative operon. However, transcription of this operon and its subsequent effects on biological pathways has not been fully studied. Here, we characterized the operon in terms of promoter activity, transcription, and function. Promoter activity assays identified two new growth- and cold-shock-responsive upstream (PymdA) and inner (PclsC) promoters, respectively. Moreover, investigation of the operon-derived transcripts identified different polycistronic transcripts harboring multiple heterogeneous 3' ends...