antibiotic resistance and biofilm formation

In Staphylococcus aureus, adherence and secretory proteins play chief role in the formation of biofilms. This mode of growth exhibits resistance to a variety of antibiotics and spreads its infections. In the present study, secretary and adherence proteins, Protein-A, Fibronectin-binding protein-A (FnbA) and Rsp (a transcription regulator encoding proteolytic property) expression levels were evaluated at different stages of growth in S. aureus ATCC12600 a drug-sensitive strain and multidrug-resistant strains of S...

Vancomycin-resistant microorganisms are a hurdle that traditional antibiotics struggle to overcome. These difficulties have led to search for new solutions based on natural products. Chitosan has been recognized as an effective antibacterial agent against a vast array of microorganisms including antibiotic resistant ones. As such, this work aimed to evaluate chitosan as an alternative to traditional antibiotics in the management/control of two vancomycin-resistant microorganisms, VRSA and VREF, in planktonic and sessile settings...

AIM: To isolate and characterize the two phenotypically distinct subpopulations from Klebsiella pneumoniae clonal cultures grown in the simulate microgravity environment. MATERIALS & METHODS: Here clonal culture of K. pneumoniae strain ATCC BAA-1705 was grown within a vertically rotating wall vessel bioreactor. Microscopic, colony staining, biofilm assays and quantitative proteomics were used to define the features of subpopulations. RESULTS: Two subpopulations were isolated based on colony appearance and bacterial morphology and indicated the different capability of biofilm formation and antibiotics resistance...

BACKGROUND: Despite the employment of sanitary regimes, contact transmission of the aetiological agents of hospital infections is still exceedingly common. The issue of microbe transmission becomes particularly important when facing multidrug-resistant microorganisms such as methicillin-resistant staphylococci. In the case of deficiencies in cleaning and disinfection procedures, hospital equipment made of copper alloys can play an important role, complementing traditional hospital hygiene procedures...

Pseudomonas aeruginosa (P. aeruginosa) is a common pathogen in hospital-acquired infection and is readily able to form biofilms. Due to its high antibiotic resistance, traditional antibacterial treatments exert a limited effect on P. aeruginosa biofilm infections. It has been indicated that hyperoside inhibits P. aeruginosa PAO1 (PAO1) biofilm formation without affecting growth. Therefore, the current study examined the biofilm formation and quorum sensing (QS) system of PAO1 in the presence of hyperoside. Confocal laser scanning microscopy analysis demonstrated that hyperoside significantly inhibited biofilm formation...

A biofilm, a community of microorganisms, is highly resistant to antibiotics, resulting in massive losses in various areas. We herein present a strategy to remove Streptococcus mutans biofilms through a spontaneous exfoliation by the synergistic effect between zwitterion and sugar alcohols. It is assumed that the anionic site of zwitterion can be coupled with sugar alcohols and the cationic site remains in the state of lacking electrons. The cationic site allows the complexes to be delivered to negatively charged exopolysaccharides of biofilms...

Staphylococcus epidermidis has emerged as an important opportunistic pathogen causing orthopedic device-related infections (ODRIs). This study investigated the association of genome variation and phenotypic features of the infecting S. epidermidis isolate with the clinical outcome of the infected patient. S. epidermidis isolates were collected from 104 patients with ODRI. Their clinical outcome was evaluated, after an average of 26 months, as either "cured" or "not cured". The isolates were tested for antibiotic susceptibility and biofilm formation...

ZnO nanoparticles (NPs) are arising as promising novel antibiotics toward device-related infections. The surface functionalization of Zn, a novel resorbable biomaterial, with ZnO NPs could present an effective solution to overcome such a threat. In this sense, the antibacterial and antibiofilm activity of nano- and microsized ZnO coatings was studied against clinically relevant bacteria, methicillin resistant Staphylococcus aureus (MRSA). The bacterial viability of planktonic and biofilm cells together with the corresponding biofilm structures revealed that only the nanosized ZnO coating had an antibiofilm effect...

Antibacterial resistance is an issue of increasing severity as current antibiotics are losing their effectiveness and fewer antibiotics are being developed. New methods for combating bacterial virulence are required. Modulating molecular communication among bacteria can alter phenotype, including attachment to epithelia, biofilm formation and even toxin production. Intercepting and modulating communication networks provide a means to attenuate virulence without directly interacting with the bacteria of interest...

The regulation of biofilm development requires multiple mechanisms and pathways, but it is not fully understood how these are integrated. Small RNA post-transcriptional regulators are a strong candidate as a regulatory mechanism of biofilm formation. More than 200 small RNAs in the P. aeruginosa genome have been characterized in the literature to date; however, little is known about their biological roles in the cell. Here we describe the identification of the novel regulatory small RNA, SrbA. This locus was up-regulated 45-fold in P...

Staphylococcus aureus bacteria are one of the leading microorganisms responsible for nosocomial infections as well as being the primary causative pathogen of skin and wound infections. Currently, the therapy of staphylococcal diseases faces many difficulties, due to a variety of mechanisms of resistance and virulence factors. Moreover, a number of infections caused by S. aureus are connected with biofilm formation that impairs effectiveness of the therapy. Short cationic lipopeptides that are designed on the basis of the structure of antimicrobial peptides are likely to provide a promising alternative to conventional antibiotics...

Formation of bacterial biofilms on medical devices can cause severe or fatal infectious diseases. In particular, biofilm-associated infections caused by methicillin-resistant Staphylococcus aureus are difficult to eradicate because the biofilm is strongly resistant to antibiotics and the host immune response. There is no effective treatment for biofilm-associated infectionss, except for surgical removal of contaminated medical devices followed by antibiotic therapy. Here we show that norgestimate, an acetylated progestin, effectively inhibits biofilm formation by staphylococcal strains, including methicillin-resistant S...

Nosocomial infections caused by Pseudomonas aeruginosa are difficult to treat due to the low permeability of its outer membrane as well as to its remarkable ability to acquire further resistance to antibiotics. Chensinin-1b exhibited antibacterial activity against the tested multiple-drug-resistant bacteria with a MIC ranging between 1.56 and 50μM, except E. cloacae strain 0320 (MREC0320), P. fluorescens strain 0322 (MRPF0322) and E. aerogenes strain 0320 (MREA0320). However, the MIC (25μM) of chensinin-1b to multiple-drug-resistant P...

With antibiotic resistance increasing at alarming rates, targets for new antimicrobial therapies must be identified. A particularly promising target is the bacterial two-component system. Two-component systems allow bacteria to detect, evaluate and protect themselves against changes in the environment, such as exposure to antibiotics, and also to trigger production of virulence factors. Drugs that target the response regulator portion of two-component systems represent a potent new approach so far unexploited...

Foley catheters are inevitable in health care unit. Pathogens colonise and form biofilm on catheter causing catheter-associated urinary tract infection. Therefore, the authors aimed to functionalise catheter to resist biofilm formation. The authors impregnated urinary catheters with a synergistic combination of antibiotics and silver nanoparticles (SNPs) to evaluate antibiofilm efficacy in vitro and in vivo. SNPs were synthesised using Spirulina platensis. Synergy between the SNPs and antibiotics was determined by the checker-board method...

Cystic fibrosis (CF) patients are predisposed to chronic colonization of the major airways by Pseudomonas aeruginosa biofilms. Pulmonary infections, involving sessile bacteria, are the main cause of morbidity and mortality. As the eradication of antibiotic-resistant biofilms remains impossible, one key objective for the treatment of lung infections is to delay the switch of P. aeruginosa to a sessile phenotype. Few tools are currently available in hospital laboratories to evaluate the susceptibility of adherent microorganisms to antimicrobials...

Bacterial cells possess a signal transduction system that differs from those described in higher organisms, including human cells. These so-called two-component signal transduction systems (TCSs) consist of a sensor (histidine kinase, HK) and a response regulator, and are involved in cellular functions, such as virulence, drug resistance, biofilm formation, cell wall synthesis, cell division. They are conserved in bacteria across all species. Although TCSs are often studied and characterized individually, they are assumed to interact with each other and form signal transduction networks within the cell...

AIMS: Multi-drug resistant Klebsiella pneumoniae has become a relevant healthcare-associated pathogen. Capsule, type 1 and 3 fimbriae (mrkA gene), type 2 quorum-sensing system (luxS), synthesis of D-galactan I (wbbM), LPS transport (wzm) and poly-beta-1,6-N-acetyl-D-glucosamine (pgaA) seem involved in K. pneumoniae biofilm. Non-enzymatic antibiotic resistance is related to non-expression or mutation of porins (OmpK35 and OmpK36), and efflux pump (acrB) over-expression. The aim of this study was to analyse some virulence factors of K...

BACKGROUND: Biofilm produced from Pseudomonas aeruginosa is the cause of infection induced by contact lenses, trauma and post-surgery infection. The aim of this study was to evaluate biofilm formation and the presence of the genes ndvB and tssC1 in ocular infection isolates of P. aeruginosa. METHODS: A total of 92 P. aeruginosa strains were collected from patients with ocular infection referred to Farabi Hospital between March 2014 and July 2015. Antibiotic susceptibility patterns were evaluated by the agar disc-diffusion method according to CLSI guidelines...

Enterococci are nosocomial pathogens that can form biofilms, which contribute to their virulence and antibiotic resistance. Although many genes involved in biofilm formation have been defined, their distribution among enterococci has not been comprehensively studied on a genome scale, and their diagnostic ability to predict biofilm phenotypes is not fully established. Here, we assessed the biofilm-forming ability of 90 enterococcal clinical isolates. Major patterns of virulence gene distribution in enterococcal genomes were identified, and the differentiating virulence genes were screened by polymerase chain reaction (PCR) in 31 of the clinical isolates...