Comparison of performances of flexible sensors on foil and paper for efficient bacterial concentration measurement

Sensor Review ◽  
2020 ◽  
Vol 40 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Tijana Kojic ◽  
Milan Radovanovic ◽  
Goran M. Stojanovic ◽  
Bojana Pivas ◽  
Deana Medic ◽  
...  

Purpose The purpose of this study was to develop flexible sensors for detection of different concentrations of bacteria, such as Pseudomonas aeruginosa and Staphylococcus aureus, in saline. Design/methodology/approach The sensors were fabricated using ink-jet printing technology and they consist of a pair of silver interdigitated electrodes printed on mechanically flexible substrates – foil and paper. In house measurement setup for testing and characterization of sensors has been developed. Structural, electrical and mechanical properties of flexible sensors have been determined and compared. Findings The characteristics of sensor – the resonant frequency as a function of different concentrations of each bacteria – are presented. The obtained results demonstrate different resonant frequencies for each dilution of Pseudomonas aeruginosa and Staphylococcus aureus in physiological saline. Research limitations/implications Both sensors showed accurate measurements of bacterial count, which can be achieved with detection of resonant frequency, and this is reflective of the number of bacterial cells within a sample. Practical implications The findings suggest that the newly developed method based on measuring resonant frequency corresponds well with bacterial cell count, thus establishing a new proof-of-concept that such method can have significant applications in bacterial cell counting that are economic and easily maintained. Social implications Fast, cost-effective, accurate and non-invasive method for detection of different bacteria from saline was developed. Originality/value For the first time, comparison between performances of flexible sensors on foil and paper for bacteria detection is demonstrated. Almost linear dependence between shift of resonant frequency of developed sensors and concentration of bacteria has been obtained.

2012 ◽  
Vol 81 (1) ◽  
pp. 285-291 ◽  
Author(s):  
Sameera Sayeed ◽  
Laura Nistico ◽  
Claudette St Croix ◽  
Y. Peter Di

The human short PLUNC1 (SPLUNC1) protein has been identified as a component of the pulmonary antimicrobial response based on its structural similarity to the bactericidal/permeability-increasing (BPI) protein. Using a genetically modified mouse model, we recently verified the antimicrobial activity of SPLUNC1 againstPseudomonas aeruginosain vivo. To further define the mechanism of epithelial SPLUNC1-mediated antibacterial action, we carried out studies to determine how SPLUNC1 protects the host from acute respiratory infections.P. aeruginosatreated with recombinant human SPLUNC1 protein showed decreased growthin vitro. This antibacterial activity was due to growth inhibition, as a consequence of a SPLUNC1-induced increase in bacterial cell permeability. Removal of SPLUNC1 allowed the recovery ofP. aeruginosaand suggested no permanent cell injury or direct killing of bacteria. Further investigation showed coating of bacterial cells by SPLUNC1. We suggest that this “bacterial cell coating” is necessary for the bacteriostatic function of SPLUNC1. Additionally, we demonstrated a novel role for SPLUNC1 as a chemoattractant that facilitated migration of macrophages and neutrophils. Taking the findings together, we propose synergistic roles for human SPLUNC1 as an antibacterial agent with bacteriostatic and chemotactic activities.


2020 ◽  
Vol 202 (18) ◽  
Author(s):  
Giulia Orazi ◽  
Fabrice Jean-Pierre ◽  
George A. O’Toole

ABSTRACT The thick mucus within the airways of individuals with cystic fibrosis (CF) promotes frequent respiratory infections that are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent pathogens that cause CF pulmonary infections, and both are among the most common etiologic agents of chronic wound infections. Furthermore, the ability of P. aeruginosa and S. aureus to form biofilms promotes the establishment of chronic infections that are often difficult to eradicate using antimicrobial agents. In this study, we found that multiple LasR-regulated exoproducts of P. aeruginosa, including 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), siderophores, phenazines, and rhamnolipids, likely contribute to the ability of P. aeruginosa PA14 to shift S. aureus Newman norfloxacin susceptibility profiles. Here, we observe that exposure to P. aeruginosa exoproducts leads to an increase in intracellular norfloxacin accumulation by S. aureus. We previously showed that P. aeruginosa supernatant dissipates the S. aureus membrane potential, and furthermore, depletion of the S. aureus proton motive force recapitulates the effect of the P. aeruginosa PA14 supernatant on shifting norfloxacin sensitivity profiles of biofilm-grown S. aureus Newman. From these results, we hypothesize that exposure to P. aeruginosa PA14 exoproducts leads to increased uptake of the drug and/or an impaired ability of S. aureus Newman to efflux norfloxacin. Surprisingly, the effect observed here of P. aeruginosa PA14 exoproducts on S. aureus Newman susceptibility to norfloxacin seemed to be specific to these strains and this antibiotic. Our results illustrate that microbially derived products can alter the ability of antimicrobial agents to kill bacterial biofilms. IMPORTANCE Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from multiple infection sites, including the lungs of individuals with cystic fibrosis (CF) and nonhealing diabetic foot ulcers. Coinfection with P. aeruginosa and S. aureus has been shown to produce worse outcomes compared to infection with either organism alone. Furthermore, the ability of these pathogens to form biofilms enables them to cause persistent infection and withstand antimicrobial therapy. In this study, we found that P. aeruginosa-secreted products dramatically increase the ability of the antibiotic norfloxacin to kill S. aureus biofilms. Understanding how interspecies interactions alter the antibiotic susceptibility of bacterial biofilms may inform treatment decisions and inspire the development of new therapeutic strategies.


2019 ◽  
Vol 202 (8) ◽  
Author(s):  
Courtney E. Price ◽  
Dustin G. Brown ◽  
Dominique H. Limoli ◽  
Vanessa V. Phelan ◽  
George A. O’Toole

ABSTRACT Cystic fibrosis (CF) patients chronically infected with both Pseudomonas aeruginosa and Staphylococcus aureus have worse health outcomes than patients who are monoinfected with either P. aeruginosa or S. aureus. We showed previously that mucoid strains of P. aeruginosa can coexist with S. aureus in vitro due to the transcriptional downregulation of several toxic exoproducts typically produced by P. aeruginosa, including siderophores, rhamnolipids, and HQNO (2-heptyl-4-hydroxyquinoline N-oxide). Here, we demonstrate that exogenous alginate protects S. aureus from P. aeruginosa in both planktonic and biofilm coculture models under a variety of nutritional conditions. S. aureus protection in the presence of exogenous alginate is due to the transcriptional downregulation of pvdA, a gene required for the production of the iron-scavenging siderophore pyoverdine as well as the downregulation of the PQS (Pseudomonas quinolone signal) (2-heptyl-3,4-dihydroxyquinoline) quorum sensing system. The impact of exogenous alginate is independent of endogenous alginate production. We further demonstrate that coculture of mucoid P. aeruginosa with nonmucoid P. aeruginosa strains can mitigate the killing of S. aureus by the nonmucoid strain of P. aeruginosa, indicating that the mechanism that we describe here may function in vivo in the context of mixed infections. Finally, we investigated a panel of mucoid clinical isolates that retain the ability to kill S. aureus at late time points and show that each strain has a unique expression profile, indicating that mucoid isolates can overcome the S. aureus-protective effects of mucoidy in a strain-specific manner. IMPORTANCE CF patients are chronically infected by polymicrobial communities. The two dominant bacterial pathogens that infect the lungs of CF patients are P. aeruginosa and S. aureus, with ∼30% of patients coinfected by both species. Such coinfected individuals have worse outcomes than monoinfected patients, and both species persist within the same physical space. A variety of host and environmental factors have been demonstrated to promote P. aeruginosa-S. aureus coexistence, despite evidence that P. aeruginosa kills S. aureus when these organisms are cocultured in vitro. Thus, a better understanding of P. aeruginosa-S. aureus interactions, particularly mechanisms by which these microorganisms are able to coexist in proximal physical space, will lead to better-informed treatments for chronic polymicrobial infections.


2019 ◽  
Vol 8 (2) ◽  
pp. 75-82
Author(s):  
Isnamurti Ciptaningrum ◽  
Reyhan Anjani Putri

Rhizophora apiculata, merupakan jenis tanaman mangrove yang tersebar melimpah di pesisir Indonesia. Populasi tanaman bakau di Indonesia mencapai 75% dari seluruh populasi bakau di dunia. Melimpahnya tanaman ini, belum dimanfaatkan secara optimal. Berdasarkan penelitian terdahulu, diketahui Rhizophora apiculata memiliki beberapa manfaat, salah satunya sebagai antibakteri. Zatantibakteri yang tekandung pada Rhizophora apiculatayaitu tannin, flavonoid dan saponin. Tannin bekerja mengadakan komplek hidrofobik dengan protein, menginaktivasi adhesi, enzim dan protein transport dinding sel, sehingga mengganggu pertumbuhan bakteri. Flavonoid bekerja menghambat sintesis asam nukleat, menghambat fungsi membran sel dan metabolisme energisertamencegah perkembangbiakan bakteri dengan membentuk senyawa kompleks protein ekstraseluler yang akan mengganggu integritas membran sel. Saponin bekerja dengan melisiskan sel bakteri. Berdasarkan penelitian yang telahdi lakukan, ekstrak daun, kulit batang dan akar Rhizophora apiculatadapat menghambat pertumbuhan bakteri Pseudomonas aeruginosa,Staphylococcus aureus, Streptococcus sp, dan Escherichia coli.Tujuandariliterature reviewiniadalah untuk mengetahui potensi Rhizophora apiculatasebagaiantibakteri. Metode yang digunakandalamartikeliniadalahpenelusuran artikel melalui database Google Scholar dan NCBI, lalu artikel dipilih dengan meninjau judul dan abstrak artikel, melibatkan 22 pustaka baik nasional maupun internasional.Hasil dari berbagai penelusuran yang dicantumkan dalam artikel ini untuk menunjukkan adanya potensiRhizophora apiculatasebagaiantibakteri.  Kata kunci: rhizophora apiculata, zatantibakteri, kandunganrhizophora apiculata   EFFECT ANTIMICROBACTERIAL RHIZOPHORA APICULTA FOR INHIBITS GROWTH OF BACTERIA   ABSTRACT Rhizophora apiculata is a type of mangrove that is spread abundantly in the coastal areas of Indonesia. The population of mangroves in Indonesia reaches 75% of the total mangrove population in the world. The abundance of mangroves in Indonesia has not been used optimally. Based on previous research, it is known that Rhizophora apiculata has several benefits, one of them is as an antibacterial. Anti-bacterial substance found in Rhizophora apiculata are tannin, flavonoid and saponin. Tannin works by holding a hydrophobic complex with protein, inactivates adhesion, enzymes and protein transport of cell walls, thereby disturb of bacterial growth. Flavonoids, work to inhibit nucleic acid synthesis, inhibit cells membrane function and inhibit energy metabolism and prevent bacterial proliferation by forming extracellular protein complex compounds that will disturb membrane cell integrity. Saponin as an antibacterial, works by lysis of bacterial cells. Based on several studies that have been done, leaf, bark and roots extracts of Rhizophora apiculata can inhibit the growth of the bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sp. and Escherichia coli. Rhizophora apiculata has an effect in inhabiting the growth of certain bacteria.The purpose of this literature review article is to get to know about the potency of Rhizophora apiculata as an antibacterial. The method used in this article uses a review of articles from Google Scholar and NCBI databases, then the article are selected by reviewing the article titles and abstracts, involving 22 libraries both national and international.The results of various articles included in this article are to show the potency of Rhizophora apiculata as an antibacterial.   Keywords: rhizophora apiculata, anti-bacterial substance, content of rhizophora apiculata


mBio ◽  
2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Sathish Kumar ◽  
Ilana Kolodkin-Gal ◽  
Hanna Engelberg-Kulka

ABSTRACTEscherichia colimazEFis a toxin-antitoxin stress-induced module mediating cell death. It requires the quorum-sensing signal (QS) “extracellular death factor” (EDF), the penta-peptide NNWNN (EcEDF), enhancing the endoribonucleolytic activity ofE. colitoxin MazF. Here we discovered thatE. coli mazEF-mediated cell death could be triggered by QS peptides from the supernatants (SN) of the Gram-positive bacteriumBacillus subtilisand the Gram-negative bacteriumPseudomonas aeruginosa. In the SN ofB. subtilis, we found one EDF, the hexapeptide RGQQNE, calledBsEDF. In the SN ofP. aeruginosa, we found three EDFs: the nonapeptide INEQTVVTK, calledPaEDF-1, and two hexadecapeptides, VEVSDDGSGGNTSLSQ, calledPaEDF-2, and APKLSDGAAAGYVTKA, calledPaEDF-3. When added to a dilutedE. colicultures, each of these peptides acted as an interspecies EDF that triggeredmazEF-mediated death. Furthermore, though their sequences are very different, each of these EDFs amplified the endoribonucleolytic activity ofE. coliMazF, probably by interacting with different sites onE. coliMazF. Finally, we suggest that EDFs may become the basis for a new class of antibiotics that trigger death from outside the bacterial cells.IMPORTANCEBacteria communicate with one another via quorum-sensing signal (QS) molecules. QS provides a mechanism for bacteria to monitor each other’s presence and to modulate gene expression in response to population density. Previously, we addedE. coliEDF (EcEDF), the peptide NNWNN, to this list of QS molecules. Here we extended the group of QS peptides to several additional different peptides. The new EDFs are produced by two other bacteria,Bacillus subtilisandPseudomonas aeruginosa. Thus, in this study we established a “new family of EDFs.” This family provides the first example of quorum-sensing molecules participating in interspecies bacterial cell death. Furthermore, each of these peptides provides the basis of a new class of antibiotics triggering death by acting from outside the cell.


2019 ◽  
Vol 87 (12) ◽  
Author(s):  
ByungHyun Kim ◽  
TingTing Jiang ◽  
Jun-Hyun Bae ◽  
Hye Su Yun ◽  
Seong Han Jang ◽  
...  

ABSTRACT Upon microbial infection, host immune cells recognize bacterial cell envelope components through cognate receptors. Although bacterial cell envelope components function as innate immune molecules, the role of the physical state of the bacterial cell envelope (i.e., particulate versus soluble) in host immune activation has not been clearly defined. Here, using two different forms of the staphylococcal cell envelope of Staphylococcus aureus RN4220 and USA300 LAC strains, we provide biochemical and immunological evidence that the particulate state is required for the effective activation of host innate immune responses. In a murine model of peritoneal infection, the particulate form of the staphylococcal cell envelope (PCE) induced the production of chemokine (C-X-C motif) ligand 1 (CXCL1) and CC chemokine ligand 2 (CCL2), the chemotactic cytokines for neutrophils and monocytes, respectively, resulting in a strong influx of the phagocytes into the peritoneal cavity. In contrast, compared with PCE, the soluble form of cell envelope (SCE), which was derived from PCE by treatment with cell wall-hydrolyzing enzymes, showed minimal activity. PCE also induced the secretion of calprotectin (myeloid-related protein 8/14 [MRP8/14] complex), a phagocyte-derived antimicrobial protein, into the peritoneal cavity at a much higher level than did SCE. The injected PCE particles were phagocytosed by the infiltrated neutrophils and monocytes and then delivered to mediastinal draining lymph nodes. More importantly, intraperitoneally (i.p.) injected PCE efficiently protected mice from S. aureus infection, which was abolished by the depletion of either monocytes/macrophages or neutrophils. This study demonstrated that the physical state of bacterial cells is a critical factor for efficient host immune activation and the protection of hosts from staphylococcal infections.


2020 ◽  
Vol 202 (8) ◽  
Author(s):  
Michael J. Schurr

ABSTRACT In this issue of Journal of Bacteriology, Price et al. show that the Pseudomonas aeruginosa-produced exopolysaccharide alginate protects Staphylococcus aureus by dampening the expression of P. aeruginosa virulence products that usually inhibit S. aureus respiration and cell membrane integrity when the two organisms compete in other environments (C. E. Price, D. G. Brown, D. H. Limoli, V. V. Phelan, and G. A. O’Toole, J Bacteriol 202:e00559-19, 2020, https://doi.org/10.1128/jb.00559-19). This is the first report that exogenously added alginate affects P. aeruginosa competition and provides a partial explanation for S. aureus and P. aeruginosa coinfections in cystic fibrosis.


2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Camille Kolenda ◽  
Jérôme Josse ◽  
Mathieu Medina ◽  
Cindy Fevre ◽  
Sébastien Lustig ◽  
...  

ABSTRACT Staphylococcus aureus is responsible for difficult-to-treat bone and joint infections (BJIs). This is related to its ability to form biofilm and to be internalized and persist inside osteoblasts. Recently, bacteriophage therapy has emerged as a promising option to improve treatment of such infections, but data on its activity against the specific bacterial lifestyles presented above remain scarce. We evaluated the activity of a combination of three bacteriophages, recently used for compassionate treatment in France, against S. aureus HG001 in a model of staphylococcal biofilm and a model of osteoblasts infection, alone or in association with vancomycin or rifampin. The activity of bacteriophages against biofilm-embedded S. aureus was dose dependent. In addition, synergistic effects were observed when bacteriophages were combined with antibiotics used at the lowest concentrations. Phage penetration into osteoblasts was observed only when the cells were infected, suggesting a S. aureus-dependent Trojan horse mechanism for internalization. The intracellular bacterial count of bacteria in infected osteoblasts treated with bacteriophages as well as with vancomycin was significantly higher than in cells treated with lysostaphin, used as a control condition, owing to the absence of intracellular activity and the rapid killing of bacteria released after the death of infected cells. These results suggest that bacteriophages are both inactive in the intracellular compartment after being internalized in infected osteoblasts and present a delayed killing effect on bacteria released after cell lysis into the extracellular compartment, which avoids preventing them from infecting other osteoblasts. The combination of bacteriophages tested was highly active against S. aureus embedded in biofilm but showed no activity against intracellular bacteria in the cell model used.


2014 ◽  
Vol 58 (8) ◽  
pp. 4353-4361 ◽  
Author(s):  
Carlos J. Sanchez ◽  
Kevin S. Akers ◽  
Desiree R. Romano ◽  
Ronald L. Woodbury ◽  
Sharanda K. Hardy ◽  
...  

ABSTRACTWithin wounds, microorganisms predominantly exist as biofilms. Biofilms are associated with chronic infections and represent a tremendous clinical challenge. As antibiotics are often ineffective against biofilms, use of dispersal agents as adjunctive, topical therapies for the treatment of wound infections involving biofilms has gained interest. We evaluatedin vitrothe dispersive activity ofd-amino acids (d-AAs) on biofilms from clinical wound isolates ofStaphylococcus aureusandPseudomonas aeruginosa; moreover, we determined whether combinations ofd-AAs and antibiotics (clindamycin, cefazolin, oxacillin, rifampin, and vancomycin forS. aureusand amikacin, colistin, ciprofloxacin, imipenem, and ceftazidime forP. aeruginosa) enhance activity against biofilms.d-Met,d-Phe, andd-Trp at concentrations of ≥5 mM effectively dispersed preformed biofilms ofS. aureusandP. aeruginosaclinical isolates, an effect that was enhanced when they were combined as an equimolar mixture (d-Met/d-Phe/d-Trp). When combined withd-AAs, the activity of rifampin was significantly enhanced against biofilms of clinical isolates ofS. aureus, as indicated by a reduction in the minimum biofilm inhibitory concentration (MBIC) (from 32 to 8 μg/ml) and a >2-log reduction of viable biofilm bacteria compared to treatment with antibiotic alone. The addition ofd-AAs was also observed to enhance the activity of colistin and ciprofloxacin against biofilms ofP. aeruginosa, reducing the observed MBIC and the number of viable bacteria by >2 logs and 1 log at 64 and 32 μg/ml in contrast to antibiotics alone. These findings indicate that the biofilm dispersal activity ofd-AAs may represent an effective strategy, in combination with antimicrobials, to release bacteria from biofilms, subsequently enhancing antimicrobial activity.


2011 ◽  
Vol 55 (5) ◽  
pp. 2325-2334 ◽  
Author(s):  
F. Jacobsen ◽  
C. Fisahn ◽  
M. Sorkin ◽  
I. Thiele ◽  
T. Hirsch ◽  
...  

ABSTRACTWound infection is a common risk for patients with chronic nonhealing wounds, causing high morbidity and mortality. Currently, systemic antibiotic treatment is the therapy of choice, despite often leading to several side effects and the risk of an insufficient tissue penetration due to impaired blood supply. If systemically delivered, moxifloxacin penetrates well into inflammatory blister fluid, muscle, and subcutaneous adipose tissues and might therefore be a possible option for the topical treatment of skin and infected skin wounds. In this study, topical application of moxifloxacin was investigated in comparison to mupirocin, linezolid, and gentamicin using a porcine wound infection and a rat burn infection model. Both animal models were performed either by an inoculation with methicillin-resistantStaphylococcus aureus(MRSA) orPseudomonas aeruginosa. Wound fluid, tissue, and blood samples were taken, and bacterial counts as well as the moxifloxacin concentration were determined for a 14-day follow-up. A histological comparison of the rat burn wound tissues was performed. Both strains were susceptible to moxifloxacin and gentamicin, whereas mupirocin and linezolid were effective only against MRSA. All antibiotics showed efficient reduction of bacterial counts, and except with MRSA, infected burn wounds reached bacterial counts below 105CFU/g tissue. Additionally, moxifloxacin was observed to promote wound healing as determined by histologic analysis, while no induction of bacterial resistance was observed during the treatment period. The use of topical antibiotics for the treatment of infected wounds confers many benefits. Moxifloxacin is therefore an ideal candidate, due to its broad antibacterial spectrum, its high efficiency, and its potential to promote wound healing.


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