Biofilm-Associated Multi-Drug Resistance in Hospital-Acquired Infections: A Review

Antimicrobial and anti-biofilm efficacy of different inorganic and organic zinc forms against multidrug-resistant Escherichia, Klebsiella, Staphylococcus and Pseudomonas

In our study antibacterial and anti-biofilm efficacy of 2 inorganics (Zn(II) sulphate monohydrate; Zn(II) sulphate heptahydrate) and 3 organic Zn(II) substances (Zn(II) chelate of protein hydrolysate: Zn-Bio; Zn(II) chelate of amino acid hydrate: Zn-AMK; Zn(II) chelate of glycine hydrate: Zn-Gly) were explored and compared against multidrug resistant Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Klebsiella oxytoca (K. oxytoca) and Pseudomonas aeruginosa (P. aeruginosa) using by the 96- wells microtiter plate-based resazurin and/or crystal violet assay. Our finding confirmed that Zn(II)-sulphates and Zn(II)-amino acid complexes exhibit dose and genus-based antibacterial and anti-biofilm potential. Organic compounds (Zn-AMK and Zn-Gly) were more effective against bacterial growth, except P. aeruginosa. Besides Zn-AMK, others organic and inorganic forms of Zn(II) caused predominantly statistically significant decrease of biofilm production in all of tested bacteria. Current data highlights that Zn(II) in various forms has a great potential to be developed as antibacterial and anti-biofilm agents.

The bacillithiol pathway is required for biofilm formation in Staphylococcus aureus

Staphylococcus aureus is a major human pathogen that can cause infections that range from superficial skin and mucosal infections to life threatening disseminated infections. S. aureus can attach to medical devices and host tissues and form biofilms that allow the bacteria to evade the host immune system and provide protection from antimicrobial agents. To counter host-generated oxidative and nitrosative stress mechanisms that are part of the normal host responses to invading pathogens, S. aureus utilizes low molecular weight (LMW) thiols, such as bacillithiol (BSH). Additionally, S. aureus synthesizes its own nitric oxide (NO), which combined with its downstream metabolites may also protect the bacteria against specific host responses. We have previously shown that LMW thiols are required for biofilm formation in Mycobacterium smegmatis and Pseudomonas aeruginosa. Here, we show that the S. aureus bshC mutant strain, which is defective in the last step of the BSH pathway and lacks BSH, is impaired in biofilm formation. We also identify a possible S-nitrosobacillithiol reductase (BSNOR), similar in sequence to an S-nitrosomycothiol reductase found in M. smegmatis and show that the putative S. aureus bsnoR mutant strain has reduced levels of BSH and decreased biofilm formation. Our studies also show that NO plays an important role in biofilm formation and that acidified sodium nitrite severely reduces biofilm thickness. These studies provide insight into the roles of oxidative and nitrosative stress mechanisms on biofilm formation and indicate that BSH and NO are key players in normal biofilm formation in S. aureus.

Dual-function antimicrobial-antibiofilm peptide hybrid to tackle biofilm-forming Staphylococcus epidermidis

BACKGROUND

Due to their resistance and difficulty in treatment, biofilm-associated infections are problematic among hospitalized patients globally and account for 60% of all bacterial infections in humans. Antibiofilm peptides have recently emerged as an alternative treatment since they can be effectively designed and exert a different mode of biofilm inhibition and eradication.

METHODS

A novel antibiofilm peptide, BiF, was designed from the conserved sequence of 18 α-helical antibiofilm peptides by template-assisted technique and its activity was improved by hybridization with a lipid binding motif (KILRR). Novel antibiofilm peptide derivatives were modified by substituting hydrophobic amino acids at positions 5 or 7, and both, with positively charged lysines (L5K, L7K). These peptide derivatives were tested for antibiofilm and antimicrobial activities against biofilm-forming Staphylococcus epidermidis and multiple other microbes using crystal violet and broth microdilution assays, respectively. To assess their impact on mammalian cells, the toxicity of peptides was determined through hemolysis and cytotoxicity assays. The stability of candidate peptide, BiF2_5K7K, was assessed in human serum and its secondary structure in bacterial membrane-like environments was analyzed using circular dichroism. The action of BiF2_5K7K on planktonic S. epidermidis and its effect on biofilm cell viability were assessed via viable counting assays. Its biofilm inhibition mechanism was investigated through confocal laser scanning microscopy and transcription analysis. Additionally, its ability to eradicate mature biofilms was examined using colony counting. Finally, a preliminary evaluation involved coating a catheter with BiF2_5K7K to assess its preventive efficacy against S. epidermidis biofilm formation on the catheter and its surrounding area.

RESULTS

BiF2_5K7K, the modified antibiofilm peptide, exhibited dose-dependent antibiofilm activity against S. epidermidis. It inhibited biofilm formation at subinhibitory concentrations by altering S. epidermidis extracellular polysaccharide production and quorum-sensing gene expression. Additionally, it exhibited broad-spectrum antimicrobial activity and no significant hemolysis or toxicity against mammalian cell lines was observed. Its activity is retained when exposed to human serum. In bacterial membrane-like environments, this peptide formed an α-helix amphipathic structure. Within 4 h, a reduction in the number of S. epidermidis colonies was observed, demonstrating the fast action of this peptide. As a preliminary test, a BiF2_5K7K-coated catheter was able to prevent the development of S. epidermidis biofilm both on the catheter surface and in its surrounding area.

CONCLUSIONS

Due to the safety and effectiveness of BiF2_5K7K, we suggest that this peptide be further developed to combat biofilm infections, particularly those of biofilm-forming S. epidermidis.

Ten Challenges to Understanding and Managing the Insect-Transmitted, Xylem-Limited Bacterial Pathogen Xylella fastidiosa

An unprecedented plant health emergency in olives has been registered over the last decade in Italy, arguably more severe than what occurred repeatedly in grapes in the United States in the last 140 years. These emergencies are epidemics caused by a stealthy pathogen, the xylem-limited, insect-transmitted bacterium Xylella fastidiosa. Although these epidemics spurred research that answered many questions about the biology and management of this pathogen, many gaps in knowledge remain. For this review, we set out to represent both the U.S. and European perspectives on the most pressing challenges that need to be addressed. These are presented in 10 sections that we hope will stimulate discussion and interdisciplinary research. We reviewed intrinsic problems that arise from the fastidious growth of X. fastidiosa, the lack of specificity for insect transmission, and the economic and social importance of perennial mature woody plant hosts. Epidemiological models and predictions of pathogen establishment and disease expansion, vital for preparedness, are based on very limited data. Most of the current knowledge has been gathered from a few pathosystems, whereas several hundred remain to be studied, probably including those that will become the center of the next epidemic. Unfortunately, aspects of a particular pathosystem are not always transferable to others. We recommend diversification of research topics of both fundamental and applied nature addressing multiple pathosystems. Increasing preparedness through knowledge acquisition is the best strategy to anticipate and manage diseases caused by this pathogen, described as "the most dangerous plant bacterium known worldwide."

Bacteriology of endotracheal tube biofilms and antibiotic resistance: a systematic review

Bacteria commonly adhere to surfaces and produce polymeric material to encase the attached cells to form communities called biofilms. Within these biofilms, bacteria can appear to be many times more resistant to antibiotics or disinfectants. This systematic review explores the prevalence and microbial profile associated with biofilm production of bacteria isolated from endotracheal tubes and its associations with antimicrobial resistance. A comprehensive search was performed on databases PubMed, Embase, and Google Scholar for relevant articles published between 1st January 2000 and 31st December 2022. The relevant articles were exported to Mendeley Desktop 1.19.8 and screened by title and abstract, followed by full text screening based on the eligibility criteria of the study. Quality assessment of the studies was performed using the Newcastle-Ottawa Scale (NOS) customized for cross-sectional studies. Furthermore, the prevalence of antimicrobial resistance in biofilm-producers isolated from endotracheal tube specimens was investigated. Twenty studies encompassing 981 endotracheal tubes met the eligibility criteria. Pseudomonas spp. and Acinetobacter spp. were predominant isolates among the biofilm producers. These biofilms provided strong resistance against commonly used antibiotics. The highest resistance rate observed in Pseudomonas spp. was against fluoroquinolones whereas the least resistance was seen against piperacillin-tazobactam. A similar trend of susceptibility was observed in Acinetobacter spp. with a very high resistance rate against fluoroquinolones, third-generation cephalosporins and carbapenems. In conclusion, endotracheal tubes were associated with colonization by biofilm forming bacteria with varying levels of antimicrobial resistance. Biofilms may promote the occurrence of recalcitrant infections in endotracheal tubes which need to be managed with appropriate protocols and antimicrobial stewardship. Research focus should shift towards meticulous exploration of biofilm-associated infections to improve detection and management.

Study on the inhibition activity and mechanism of Tanreqing against Klebsiella pneumoniae biofilm formation in vitro and in vivo

Objective

To evaluate the antibacterial effect of Tanreqing (TRQ) against K. pneumoniae and its inhibition activity on bacterial biofilm formation in vitro and in vivo, and to explore the mechanism of the inhibitory effects of TRQ on K. pneumoniae biofilm formation.

Methods

An in vitro biofilm model of K. pneumoniae was established, and the impact of TRQ on biofilm formation was evaluated using crystal violet staining and scanning electron microscopy (SEM). Furthermore, the clearance effect of TRQ against K. pneumoniae in the biofilm was assessed using the viable plate counting method; q-RT PCR was used to evaluate the inhibitory effect of different concentrations of TRQ on the expression of biofilm-related genes in Klebsiella pneumoniae; The activity of quorum sensing signal molecule AI-2 was detected by Vibrio harveyi bioluminescence assay; Meanwhile, a guinea pig lung infection model of Klebsiella pneumoniae was constructed, and after treated with drugs, pathological analysis of lung tissue and determination of bacterial load in lung tissue were performed. The treatment groups included TRQ group, imipenem(IPM) group, TRQ+IPM group, and sterile saline group as the control.

Results

The formation of K. pneumoniae biofilm was significantly inhibited by TRQ in vitro experiments. Furthermore, when combined with IPM, the clearance of K. pneumoniae in the biofilm was notably increased compared to the TRQ group and IPM group alone. q-RT PCR analysis revealed that TRQ down-regulated the expression of genes related to biofilm formation in K. pneumoniae, specifically luxS, wbbm, wzm, and lsrK, and also inhibited the activity of AI-2 molecules in the bacterium. In vivo experiments demonstrated that TRQ effectively treated guinea pig lung infections, resulting in reduced lung inflammation. Additionally, when combined with IPM, there was a significant reduction in the bacterial load in lung tissue.

Conclusion

TRQ as a potential therapeutic agent plays a great role in the treatment of K. pneumoniae infections, particularly in combination with conventional antibiotics. And TRQ can enhanced the clearance effect on the bacterium by inhibiting the K. pneumoniae biofilm formation, which provided experimental evidence in support of clinical treatment of TRQ against K. pneumoniae infections.

Synergistic bactericidal effects of phage-enhanced antibiotic therapy against MRSA biofilms

Methicillin-resistant Staphylococcus aureus (MRSA) causes biofilm-related medical device infections. Phage-antibiotic combinations offer potential therapy due to proven in vitro antibiofilm efficacy. We evaluated phage-antibiotic synergy against biofilms using modified checkerboard and 24-h time-kill assays. Humanized-simulated daptomycin (DAP) (10, 8, and 6 mg/kg q24h) and ceftaroline (CPT) (600 mg q12h) were combined with Intesti13, Sb-1, and Romulus phages (tMOI 1, q12h). Assays were conducted in 168-h biofilm reactor models against DAP non-susceptible (DNS) vancomycin intermediate S. aureus (VISA) MRSA D712 and DAP-susceptible MRSA 8014. Synergistic activity and bactericidal activity were defined as ≥2log10 CFU/mL reduction from antibiotic-only regimens and ≥3log10 CFU/mL decrease from baseline at 24 h. Differences were analyzed by one-way analysis of variance with Tukey's post hoc test (P ≤ 0.05 is considered significant). Surviving bacteria were examined for antibiotic minimum biofilm inhibitory concentration (MBIC) changes and phage susceptibility. In 168-h biofilm models, humanized DAP 10 mg/kg + CPT, combined with a 2-phage cocktail (Intesti13 + Sb-1) against D712, and a 3-phage cocktail (Intesti13 + Sb-1 + Romulus) against 8014, demonstrated synergistic bactericidal activity. At 168 h, bacteria were minimally detectable [2log10 CFU/cm2 (-Δ4.23 and -Δ4.42 log10 CFU/cm2; both P < 0.001)]. Antibiotic MBIC remained unchanged compared to baseline across various time points. None of the tested bacteria at 168 h exhibited complete phage resistance. This study reveals bactericidal efficacy of DAP + CPT with 2-phage and 3-phage cocktails against DNS VISA and MRSA isolates (D712 and 8014) in biofilm models, maintaining susceptibility. Further research is needed for diverse strains and durations, aligning with infection care.

IMPORTANCE

The prevalence of biofilm-associated medical device infections caused by methicillin-resistant Staphylococcus aureus (MRSA) presents a pressing medical challenge. The latest research demonstrates the potential of phage-antibiotic combinations (PACs) as a promising solution, notably in vitro antibiofilm efficacy. By adopting modified checkerboard and 24-h time-kill assays, the study investigated the synergistic action of phages combined with humanized-simulated doses of daptomycin (DAP) and ceftaroline (CPT). The results were promising: a combination of DAP, CPT, and either a 2-phage or 3-phage cocktail effectively exhibited bactericidal activity against both DAP non-susceptible vancomycin intermediate S. aureus MRSA and DAP-susceptible MRSA strains within 168-h biofilm models. Moreover, post-treatment evaluations revealed no discernible rise in antibiotic resistance or complete phage resistance. This pioneering work suggests the potential of PACs in addressing MRSA biofilm infections, setting the stage for further expansive research tailored to diverse bacterial strains and treatment durations.

Prebiotic levan type fructan from Bacillus subtilis PR-C18 as a potent antibiofilm agent: Structural elucidation and in silico analysis

The global demand for therapeutic prebiotics persuades the quest for novel exopolysaccharides that can retard the growth of pathobionts and healthcare-associated pathogens. In this regard, an exopolysaccharide (3.69 mg/mL) producing strain showing prebiotic and antibiofilm activity was isolated from indigenous pineapple pomace of Tripura and identified as Bacillus subtilis PR-C18. Zymogram analysis revealed EPS PR-C18 was synthesized by levansucrase (∼57 kDa) with a maximal activity of 4.62 U/mg. Chromatography techniques, FTIR, and NMR spectral data revealed the homopolymeric nature of purified EPS with a molecular weight of 3.40 × 104 Da. SEM and rheological study unveiled its microporous structure and shear-thinning effect. Furthermore, EPS PR-C18 showed remarkable emulsification, flocculation, water retention, water solubilization, and antioxidant activity. DSC-TGA data demonstrated its high thermostability and cytotoxicity analysis verified its nontoxic biocompatible nature. In addition, the antibiofilm activity of EPS PR-C18 was validated using molecular docking, molecular simulation, MM-GBSA and PCA studies, which exhibited its strong binding affinity (-20.79 kcal/moL) with PelD, a virulence factor from Pseudomonas aeruginosa. Together, these findings support the future exploitation of EPS PR-C18 as an additive or adjuvant in food and pharmaceutical sectors.

Improving Activity of New Arylurea Agents against Multidrug-Resistant and Biofilm-Producing Staphylococcus epidermidis

Multidrug-resistant (MDR) strains of Staphylococcus epidermidis (S. epidermidis), prevalent in hospital environments, contribute to increased morbidity and mortality, especially among newborns, posing a critical concern for neonatal sepsis. In response to the pressing demand for novel antibacterial therapies, we present findings from synthetic chemistry and structure-activity relationship studies focused on arylsulfonamide/arylurea derivatives of aryloxy[1-(thien-2-yl)propyl]piperidines. Through bioisosteric replacement of the sulfonamide fragment with a urea moiety, compound 25 was identified, demonstrating potent bacteriostatic activity against clinical multidrug-resistant S. epidermidis strains (MIC50 and MIC90 = 1.6 and 3.125 μg/mL). Importantly, it showed activity against linezolid-resistant strains and exhibited selectivity over mammalian cells. Compound 25 displayed antibiofilm-forming properties against clinical S. epidermidis strains and demonstrated the capacity to eliminate existing biofilm layers. Additionally, it induced complete depolarization of the bacterial membrane in clinical S. epidermidis strains. In light of these findings, targeting bacterial cell membranes with compound 25 emerges as a promising strategy in the fight against multidrug-resistant S. epidermidis strains.

Biofilm-mediated infections by multidrug-resistant microbes: a comprehensive exploration and forward perspectives

A biofilm is a collection of microorganisms organized in a matrix of extracellular polymeric material. Biofilms consist of microbial cells that attach to both surfaces and each other, whether they are living or non-living. These microbial biofilms can lead to hospital-acquired infections and are generally detrimental. They possess the ability to resist the human immune system and antibiotics. The National Institute of Health (NIH) states that biofilm formation is associated with 65% of all microbial illnesses and 80% of chronic illnesses. Additionally, non-device-related microbial biofilm infections include conditions like cystic fibrosis, otitis media, infective endocarditis, and chronic inflammatory disorders. This review aims to provide an overview of research on chronic infections caused by microbial biofilms, methods used for biofilm detection, recent approaches to combat biofilms, and future perspectives, including the development of innovative antimicrobial strategies such as antimicrobial peptides, bacteriophages, and agents that disrupt biofilms.

Novel Antimicrobial Approaches to Combat Bacterial Biofilms Associated with Urinary Tract Infections

Urinary tract infections (UTIs) are prevalent bacterial infections in both community and healthcare settings. They account for approximately 40% of all bacterial infections and require around 15% of all antibiotic prescriptions. Although antibiotics have traditionally been used to treat UTIs for several decades, the significant increase in antibiotic resistance in recent years has made many previously effective treatments ineffective. Biofilm on medical equipment in healthcare settings creates a reservoir of pathogens that can easily be transmitted to patients. Urinary catheter infections are frequently observed in hospitals and are caused by microbes that form a biofilm after a catheter is inserted into the bladder. Managing infections caused by biofilms is challenging due to the emergence of antibiotic resistance. Biofilms enable pathogens to evade the host's innate immune defences, resulting in long-term persistence. The incidence of sepsis caused by UTIs that have spread to the bloodstream is increasing, and drug-resistant infections may be even more prevalent. While the availability of upcoming tests to identify the bacterial cause of infection and its resistance spectrum is critical, it alone will not solve the problem; innovative treatment approaches are also needed. This review analyses the main characteristics of biofilm formation and drug resistance in recurrent uropathogen-induced UTIs. The importance of innovative and alternative therapies for combatting biofilm-caused UTI is emphasised.

Bacteriophage-based approach for treatment of urinary tract infections: a quick outlook

Urinary tract infections (UTIs) are among the most common bacterial infections affecting millions worldwide. The increasing emergence of antibiotic-resistant bacteria has become a serious concern in managing UTIs. Therefore, there is a growing interest in using bacteriophages as an alternative or adjunct therapy for UTIs. Bacteriophages are viruses that infect and kill bacteria, making them a promising tool for treating UTIs caused by antibiotic-resistant bacteria. This article provides a quick outlook on using bacteriophages to treat UTIs. We summarize the current understanding of the biology of bacteriophages, the challenges associated with developing phage-based therapies, and the promising results of several case reports and clinical trials. We also highlight the potential of phage therapy as a valuable tool in the fight against antibiotic-resistant UTIs. This quick outlook on a bacteriophage-based approach for treating UTIs offers a timely and informative summary of the current research in this field.

Electrochemical techniques for label-free and early detection of growing microbial cells and biofilms

Over the past decades, the misuse or abuse of antimicrobial agents to prevent and/or control infections has led to increased resistance of microbes to treatments, and antimicrobial resistance is now a subject of major global concern. In some cases, microbes possess the capacity to attach to biotic or abiotic surfaces, and to produce a protective polymeric matrix, forming biofilms of higher resistance and virulence compared to planktonic forms. To avoid further excessive and inappropriate use of antimicrobials, and to propose new effective treatments, it is very important to detect planktonic microbes and microbial biofilms in their early growth stage and at the point of need. In this review, we provide an overview of currently available electrochemical techniques, in particular impedimetric and voltamperometric methods, highlighting recent advances in the field and illustrating with examples in antibiotic susceptibility testing and microbial biofilm monitoring.

A comprehensive review of genomics, transcriptomics, proteomics, and metabolomic insights into the differentiation of Pseudomonas aeruginosa from the planktonic to biofilm state: A multi-omics approach

Biofilm formation by Pseudomonas aeruginosa is primarily responsible for chronic wound and lung infections in humans. These infections are persistent owing to the biofilm's high tolerance to antimicrobials and constantly changing environmental factors. Understanding the mechanism governing biofilm formation can help to develop therapeutics explicitly directed against the molecular markers responsible for this process. After numerous years of research, many genes responsible for both in vitro and in vivo biofilm development remain unidentified. However, there is no "all in one" complete in vivo or in vitro biofilm model. Recent findings imply that the shift from planktonic bacteria to biofilms is a complicated and interrelated differentiation process. Research on the applications of omics technologies in P. aeruginosa biofilm development is ongoing, and these approaches hold great promise for expanding our knowledge of the mechanisms of biofilm formation. This review discusses the different factors that affect biofilm formation and compares P. aeruginosa biofilm formation using the omics approaches targeting essential biological macromolecules, such as DNA, RNA, Protein, and metabolome. Furthermore, we have outlined the application of currently available omics tools, such as genomics, proteomics, metabolomics, transcriptomics, and integrated multi-omics methodologies, to understand the differential gene expression (biofilm vs. planktonic bacteria) of P. aeruginosa biofilms.

An Overview of Biofilm-Associated Infections and the Role of Phytochemicals and Nanomaterials in Their Control and Prevention

Biofilm formation is considered one of the primary virulence mechanisms in Gram-positive and Gram-negative pathogenic species, particularly those responsible for chronic infections and promoting bacterial survival within the host. In recent years, there has been a growing interest in discovering new compounds capable of inhibiting biofilm formation. This is considered a promising antivirulence strategy that could potentially overcome antibiotic resistance issues. Effective antibiofilm agents should possess distinctive properties. They should be structurally unique, enable easy entry into cells, influence quorum sensing signaling, and synergize with other antibacterial agents. Many of these properties are found in both natural systems that are isolated from plants and in synthetic systems like nanoparticles and nanocomposites. In this review, we discuss the clinical nature of biofilm-associated infections and some of the mechanisms associated with their antibiotic tolerance. We focus on the advantages and efficacy of various natural and synthetic compounds as a new therapeutic approach to control bacterial biofilms and address multidrug resistance in bacteria.

Crosslinking kiwifruit-derived DNA with natural aromatic aldehydes generates membranolytic antibacterial nanogels

Improper use of antibiotics has led to the global rise of drug-resistant biofilm bacteria. Thus, researchers have been increasingly interested in green materials that are highly biocompatible and have low toxicity. Here, nanogels (NGs) with imine bonds were synthesized by crosslinking kiwifruit-derived DNA's primary amine and aromatic aldehydes (cuminaldehyde, p-anisaldehyde, or vanillin) under water-in-hexane emulsion processes. Transmission electron microscope showed that the NGs had spherical geometry with an average particle size ranging from 40 to 140 nm and that the zeta potential indicated a negative charge. Additionally, the DNA-aromatic aldehyde NGs showed low cytotoxicity toward normal cell organoids and human RBCs in cell viability tests. These NGs were also tested against four pathogenic bacteria for various assays. DNA-vanillin (DNA-VA) NGs exhibited significant antibacterial effects against bacteria with very low inhibitory concentrations as seen in a minimum inhibitory concentration assay. Scanning electron microscope observation revealed that the bacteria were deformed, and immunoblotting detected intracellular groEL protein expression. In agreement with these results, DNA-aromatic aldehyde NGs successfully protected C. elegans from P. aeruginosa-induced lethality. These DNA NGs provided a multivalent 3D space for antibacterial aromatic aldehydes to tether, enhancing their interaction with the bacterial wall. These results offer a new direction for the development of novel antibiotics in the future.

Unveiling the Antifouling Potential of Stabilized Poly(phosphorus ylides)

Zwitterionic polymers have emerged as highly attractive building blocks for antifouling coatings in biomedical applications. Notably, these polymers offer effective alternatives to the widely used poly(ethylene glycol) (PEG), which has raised concerns regarding its immunotoxicity and the development of PEG-specific antibodies. Polymeric ylides, a largely overlooked class of zwitterionic polymers, have been reported as effective antifouling scaffolds. However, the reported subclasses, poly(sulfur ylides) and N-oxides, lack structural diversity and chemical variability. In this study, we present the synthesis and characterization of polymeric phosphorus ylides as an unexplored class of poly(ylides) with significantly increased structural diversity, which is of high value when designing future ylide-based antifouling materials. Our findings demonstrate that, owing to their low dipole moments and hydration layers, these polymeric phosphorus ylides significantly reduce bacterial attachment. Furthermore, we observe selective toxicity toward bacteria rather than mammalian cells. The bactericidal nature of poly(phosphorus ylides), coupled with their expanded chemical space, provides a distinct advantage over existing materials, including zwitterionic polymers from betaine scaffolds. We anticipate that these unexplored structures will broaden the scope of antifouling applications for poly(ylides).

Factors affecting biofilm formation by bacteria on fabrics

Fabrics act as fomites for microorganisms, thereby playing a significant role in infection transmission, especially in the healthcare and hospitality sectors. This study aimed to examine the biofilm formation ability of four nosocomial infection-causing bacteria (Acinetobacter calcoaceticus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) on cotton, polyester, polyester-cotton blend, silk, wool, viscose, and nylon, used frequently in the healthcare sector, by qualitative and quantitative methods. The impact of temperature, pH, and relative humidity (RH) on biofilm formation was also assessed. P. aeruginosa and S. aureus were strong biofilm producers, while E. coli produced weak biofilm. Wool (maximum roughness) showed the highest bacterial load, while silk (lowest roughness) showed the least. P. aeruginosa exhibited a higher load on all fabrics, than other test bacteria. Extracellular polymeric substances were characterized by infrared spectroscopy. Roughness of biofilms was assessed by atomic force microscopy. For biofilm formation, optimum temperature, pH, and RH were 30 °C, 7.0, and 62%, respectively. MgCl2 and CaCl2 were the most effective in removing bacterial biofilm. In conclusion, biofilm formation was observed to be influenced by the type of fabric, bacteria, and environmental conditions. Implementing recommended guidelines for the effective disinfection of fabrics is crucial to curb the risk of nosocomial infections. In addition, designing modified healthcare fabrics that inhibit pathogen load could be an effective method to mitigate the transmission of infections.

In Vitro Activities of Oxazolidinone Antibiotics Alone and in Combination with C-TEMPO against Methicillin-Resistant Staphylococcus aureus Biofilms

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a global health concern. The propensity of MRSA to form biofilms is a significant contributor to its pathogenicity. Strategies to treat biofilms often involve small molecules that disperse the biofilm into planktonic cells. Linezolid and, by extension, theoxazolidinones have been developed to treat infections caused by Gram-positive bacteria such as MRSA. However, the clinical development of these antibiotics has mainly assessed the susceptibility of planktonic cells to the drug. Previous studies evaluating the anti-biofilm activity of theoxazolidinones have mainly focused on the biofilm inhibition of Enterococcus faecalis and methicillin-sensitive Staphylococcus aureus, with only a few studies investigating the activity of oxazolidinones for eradicating established biofilms for these species. Very little is known about the ability of oxazolidinones to eradicate MRSA biofilms. In this work, five oxazolidinones were assessed against MRSA biofilms using a minimum biofilm eradication concentration (MBEC) assay. All oxazolidinones had inherent antibiofilm activity. However, only ranbezolid could completely eradicate MRSA biofilms at clinically relevant concentrations. The susceptibility of the MRSA biofilms to ranbezolid was synergistically enhanced by coadministration with the nitroxide biofilm dispersal agent C-TEMPO. We presume that ranbezolid acts as a dual warhead drug, which combines the mechanism of action of the oxazolidinones with a nitric oxide donor or cytotoxic drug.

Attenuation of biofilm and quorum sensing regulated virulence factors of an opportunistic pathogen Pseudomonas aeruginosa by phytofabricated silver nanoparticles

Green-synthesized nanoparticles provide an effective strategy for inhibiting microbial pathogenesis by affecting biofilm formation, quorum sensing (QS), and other surface properties of microorganisms. QS is a density-dependent communication signaling cascade that regulates biofilm formation and other pathogenic factors of Pseudomonas aeruginosa. In this context, the effect of phytofabricated silver nanoparticles (CC-AgNPs) synthesized using Cuphea carthagenensis extract on biofilm, QS, and QS-dependent virulence factors of P. aeruginosa were evaluated in this study. CC-AgNPs demonstrated significant attenuation of biofilm, QS, and QS-dependent virulence factors at sub-MICs. A significant inhibition of 88.39 ± 4.32 %, 79.64 ± 3.31 %, 73.07 ± 3.0 %, and 61.67 ± 1.5 % of biofilm formation, quorum sensing, pyocyanin, and LasB elastase, respectively was reported in the study at 20 μg/mL. The study also demonstrated a significant reduction of LasA Staphylolytic activity and 91.37 ± 1.05 % exoprotease production in comparison to untreated control. The lower concentrations of CC-AgNPs also demonstrated significant attenuation of biofilm and other virulence factors suggesting the strong potency of NPs against P. aeruginosa. XTT analysis reported the effect of CC-AgNPs on sessile cells of P. aeruginosa without impacting growth of planktonic cells at sub-MICs. Cell-proliferation study in human cell lines (HEK 293 and Caco-2 cells) demonstrated the safe nature of CC-AgNPs at tested concentrations. This study is novel in a way that environmentally friendly CC-AgNPs were used to inhibit QS at sub-MICs without killing the tested strains, therefore, could be developed as an anti-virulent drug to overcome biofilm and antimicrobial resistance problems.

Impact of Biofilms on Chronic Infections and Medical Challenges

Biofilms which are intricate colonies of bacteria encapsulated in a self-produced matrix are becoming more widely recognized for their importance in persistent infections. Biofilm-related infections provide distinct diagnostic and therapy issues needing novel approaches. Biofilms are common in clinical settings and contribute to the persistence of diseases related to medical devices, dental health, respiratory disorders, and chronic infection. Overcoming these problems requires a thorough understanding of the elements that influence biofilm development and their complex interactions within the microbial community. Emerging diagnostic techniques and therapy approaches that target biofilm-related disorders at different levels give hope for improved patient outcomes. This review looks at how biofilm formation affects chronic infections in a variety of ways, including increased drug resistance, immune system evasion, and delayed diagnosis.

Zwitterionic Polymeric Sulfur Ylides with Minimal Charge Separation Open a New Generation of Antifouling and Bactericidal Materials

Zwitterionic polymers are widely employed hydrophilic building blocks for antifouling coatings with numerous applications across a wide range of fields, including but not limited to biomedical science, drug delivery and nanotechnology. Zwitterionic polymers are considered as an attractive alternative to polyethylene glycol because of their biocompatibility and effectiveness to prevent formation of biofilms. To this end, zwitterionic polymers are classified in two categories, namely polybetaines and polyampholytes. Yet, despite a fundamental interest to drive the development of new antifouling materials, the chemical composition of zwitterionic polymer remains severely limited. Here, we show that poly(sulfur ylides) that belong to the largely overlooked class of poly(ylides), effectively prevent the formation of biofilms from pathogenic bacteria. While surface energy analysis reveals strong hydrogen-bond acceptor capabilities of poly(sulfur ylide), membrane damage of pathogenic bacteria induced by poly(sulfur ylides) indicates toxicity towards bacteria while not affecting eucaryotic cells. Such synergistic effect of poly(sulfur ylides) offers distinct advantages over polyethylene glycol when designing new antifouling materials. We expect that our findings will pave the way for the development of a range of ylide-based materials with antifouling properties that have yet to be explored, opening up new directions at the interface of chemistry, biology, and material science.

Modification of halloysite lumen with dopamine derivatives as filler for antibiofilm coating

HYPOTHESIS

Development of nanocomposite coating with antibiofilm properties is of fundamental importance to efficient fight biofilm formation preventing infections in biomedical area. In this context, halloysite nanotubes (HNTs), biocompatible and low-cost clay mineral, have been efficiently used as filler for different polymeric matrices affording several nanocomposites with appealing antimicrobial properties. The modification of HNTs surfaces represents a valuable strategy to improve the utilization of the clay for biological purposes.

EXPERIMENTS

Herein, the covalent modification of the HNTs lumen with properly designed dopamine derivatives with different perfluoroalkyl chain length is reported. The obtained nanomaterials are thoroughly characterized by several techniques. As proof of concept the antibiofilm properties on E. coli strain of the nanomaterials are assayed as well. Finally, the HNTs fillers were introduced into a polydopamine matrix allowing for the preparation of functional coatings, resistant to formation of microbial biofilms.

FINDINGS

All characterization methods proved the selectivity of the modification and the increased hydrophobicity of the lumen. In particular 27Al solid state nuclear magnetic resonance (NMR) spectra showed a upfield shift of the Al signal. Studies on the antibiofilm properties highlighted different activities according to the length of perfluoroalkyl chains of organic molecules as proved by 19F solid state NMR spectra. The synthetized materials were promising for future application as coatings on medical implants.

The Deciphering of Growth-Dependent Strategies for Quorum-Sensing Networks in Pseudomonas aeruginosa

Pseudomonas aeruginosa is recognized as a significant cause of morbidity and mortality among nosocomial pathogens. In respiratory infections, P. aeruginosa acts not only as a single player but also collaborates with the opportunistic fungal pathogen Aspergillus fumigatus. This study introduced a QS molecule portfolio as a potential new biomarker that affects the secretion of virulence factors and biofilm formation. The quantitative levels of QS molecules, including 3-o-C12-HSL, 3-o-C8-HSL, C4-HSL, C6-HSL, HHQ, PQS, and PYO, measured using mass spectrometry in a monoculture, indicated metabolic changes during the transition from planktonic to sessile cells. In the co-cultures with A. fumigatus, the profile of abundant QS molecules was reduced to 3-o-C12-HSL, C4-HSL, PQS, and PYO. A decrease in C4-HSL by 50% to 170.6 ± 11.8 ng/mL and an increase 3-o-C12-HSL by 30% up to 784.4 ± 0.6 ng/mL were detected at the stage of the coverage of the hyphae with bacteria. Using scanning electron microscopy, we showed the morphological stages of the P. aeruginosa biofilm, such as cell aggregates, maturated biofilm, and cell dispersion. qPCR quantification of the genome equivalents of both microorganisms suggested that they exhibited an interplay strategy rather than antagonism. This is the first study demonstrating the quantitative growth-dependent appearance of QS molecule secretion in a monoculture of P. aeruginosa and a co-culture with A. fumigatus.

How biofilm changes our understanding of cleaning and disinfection

Biofilms are ubiquitous in healthcare settings. By nature, biofilms are less susceptible to antimicrobials and are associated with healthcare-associated infections (HAI). Resistance of biofilm to antimicrobials is multifactorial with the presence of a matrix composed of extracellular polymeric substances and eDNA, being a major contributing factor. The usual multispecies composition of environmental biofilms can also impact on antimicrobial efficacy. In healthcare settings, two main types of biofilms are present: hydrated biofilms, for example, in drains and parts of some medical devices and equipment, and environmental dry biofilms (DSB) on surfaces and possibly in medical devices. Biofilms act as a reservoir for pathogens including multi-drug resistant organisms and their elimination requires different approaches. The control of hydrated (drain) biofilms should be informed by a reduction or elimination of microbial bioburden together with measuring biofilm regrowth time. The control of DSB should be measured by a combination of a reduction or elimination in microbial bioburden on surfaces together with a decrease in bacterial transfer post-intervention. Failure to control biofilms increases the risk for HAI, but biofilms are not solely responsible for disinfection failure or shortcoming. The limited number of standardised biofilm efficacy tests is a hindrance for end users and manufacturers, whilst in Europe there are no approved standard protocols. Education of stakeholders about biofilms and ad hoc efficacy tests, often academic in nature, is thus paramount, to achieve a better control of biofilms in healthcare settings.

Zingerone inhibits biofilm formation and enhances antibiotic efficacy against Salmonella biofilm

Salmonella enterica serovar Typhi is a significant cause of typhoid fever and a major public health problem. The ability of S. Typhi to form biofilms on living and non-living surfaces results in antibiotic resistance and poses a major challenge in health care. In this study, we assessed the ability of zingerone alone and in combination with antibiotics against the motility phenotypes and biofilm-forming ability of S. Typhi. Results showed that zingerone effectively reduced the swimming, swarming, and twitching phenotypes and exhibited biofilm inhibition potential. Moreover, zingerone enhanced the antibiofilm activity of ciprofloxacin and kanamycin. Microscopic analysis revealed a thinner biofilm in the presence of zingerone, which may have enhanced the antibiofilm efficacy of the antibiotics. The microscopic analysis showed that the presence of zingerone resulted in a reduction in the thickness of the biofilm, potentially increasing the antibiofilm efficacy of the antibiotics. In silico molecular docking and simulation studies further indicated that zingerone may bind to the fimbriae subunits (FimA, FimC, FimH, and FimY) of S. Typhi and form stable interactions. These findings provide important insights into the potential of zingerone to target biofilm-associated Salmonella infections. Further research is considered a promising option for designing innovative approaches to prevent infections associated with biofilms. Schematic representation of the role of zingerone in biofilm, motility inhibition and molecular interactions with biofilm associated proteins.

Bacterial Biofilm Formation on Biomaterials and Approaches to Its Treatment and Prevention

Bacterial biofilms can cause widespread infection. In addition to causing urinary tract infections and pulmonary infections in patients with cystic fibrosis, biofilms can help microorganisms adhere to the surfaces of various medical devices, causing biofilm-associated infections on the surfaces of biomaterials such as venous ducts, joint prostheses, mechanical heart valves, and catheters. Biofilms provide a protective barrier for bacteria and provide resistance to antimicrobial agents, which increases the morbidity and mortality of patients. This review summarizes biofilm formation processes and resistance mechanisms, as well as the main features of clinically persistent infections caused by biofilms. Considering the various infections caused by clinical medical devices, we introduce two main methods to prevent and treat biomaterial-related biofilm infection: antibacterial coatings and the surface modification of biomaterials. Antibacterial coatings depend on the covalent immobilization of antimicrobial agents on the coating surface and drug release to prevent and combat infection, while the surface modification of biomaterials affects the adhesion behavior of cells on the surfaces of implants and the subsequent biofilm formation process by altering the physical and chemical properties of the implant material surface. The advantages of each strategy in terms of their antibacterial effect, biocompatibility, limitations, and application prospects are analyzed, providing ideas and research directions for the development of novel biofilm infection strategies related to therapeutic materials.

Synergistic Photodynamic/Antibiotic Therapy with Photosensitive MOF-Based Nanoparticles to Eradicate Bacterial Biofilms

Bacterial biofilms pose a serious threat to human health, as they prevent the penetration of antimicrobial agents. Developing nanocarriers that can simultaneously permeate biofilms and deliver antibacterial agents is an attractive means of treating bacterial biofilm infections. Herein, photosensitive metal-organic framework (MOF) nanoparticles were developed to promote the penetration of antibiotics into biofilms, thereby achieving the goal of eradicating bacterial biofilms through synergistic photodynamic and antibiotic therapy. First, a ligand containing benzoselenadiazole was synthesized and incorporated into MOF skeletons to construct benzoselenadiazole-doped MOFs (Se-MOFs). The growth of the Se-MOFs could be regulated to obtain nanoparticles (Se-NPs) in the presence of benzoic acid. The singlet oxygen (¹O₂) generation efficiencies of the Se-MOFs and Se-NPs were evaluated. The results show that the Se-NPs exhibited a higher ¹O₂ generation efficacy than the Se-MOF under visible-light irradiation because the small size of the Se-NPs was conducive to the diffusion of ¹O₂. Afterward, an antibiotic drug, polymyxin B (PMB), was conjugated onto the surface of the Se-NPs via amidation to yield PMB-modified Se-NPs (PMB-Se-NPs). PMB-Se-NPs exhibit a synergistic antibacterial effect by specifically targeting the lipopolysaccharides present in the outer membranes of Gram-negative bacteria through surface-modified PMB. Benefiting from the synergistic therapeutic effects of antibiotic and photodynamic therapy, PMB-Se-NPs can efficiently eradicate bacterial biofilms at relatively low antibiotic doses and light intensities, providing a promising nanocomposite for combating biofilm infections.

A review of Spaulding's classification system for effective cleaning, disinfection and sterilization of reusable medical devices: Viewed through a modern-day lens that will inform and enable future sustainability

Despite advances in medicine and innovations in many underpinning fields including disease prevention and control, the Spaulding classification system, originally proposed in 1957, remains widely used for defining the disinfection and sterilization of contaminated re-usable medical devices and surgical instruments. Screening PubMed and Scopus databases using a PRISMA guiding framework generated 272 relevant publications that were used in this review. Findings revealed that there is a need to evolve how medical devices are designed, and processed by cleaning, disinfection (and/or sterilization) to mitigate patient risks, including acquiring an infection. This Spaulding Classification remains in use as it is logical, easily applied and understood by users (microbiologists, epidemiologists, manufacturers, industry) and by regulators. However, substantial changes have occurred over the past 65 years that challenge interpretation and application of this system that includes inter alia emergence of new pathogens (viruses, mycobacteria, protozoa, fungi), a greater understanding of innate and adaptive microbial tolerance to disinfection, toxicity risks, increased number of vulnerable patients and associated patient procedures, and greater complexity in design and use of medical devices. Common cited examples include endoscopes that enable non- or minimal invasive procedures but are highly sophisticated with various types of materials (polymers, electronic components etc), long narrow channels, right angle and heat-sensitive components and various accessories (e.g., values) that can be contaminated with high levels of microbial bioburden and patient tissues after use. Contaminated flexible duodenoscopes have been a source of several significant infection outbreaks, where at least 9 reported cases were caused by multidrug resistant organisms [MDROs] with no obvious breach in processing detected. Despite this, there is evidence of the lack of attention to cleaning and maintenance of these devices and associated equipment. Over the last few decades there is increasing genomic evidence of innate and adaptive resistance to chemical disinfectant methods along with adaptive tolerance to environmental stresses. To reduce these risks, it has been proposed to elevate classification of higher-risk flexible endoscopes (such as duodenoscopes) from semi-critical [contact with mucous membrane and intact skin] to critical use [contact with sterile tissue and blood] that entails a transition to using low-temperature sterilization modalities instead of routinely using high-level disinfection; thus, increasing the margin of safety for endoscope processing. This timely review addresses important issues surrounding use of the Spaulding classification system to meet modern-day needs. It specifically addresses the need for automated, robust cleaning and drying methods combined with using real-time monitoring of device processing. There is a need to understand entire end-to-end processing of devices instead of adopting silo approaches that in the future will be informed by artificial intelligence and deep-learning/machine learning. For example, combinational solutions that address the formation of complex biofilms that harbour pathogenic and opportunistic microorganisms on the surfaces of processed devices. Emerging trends are addressed including future sustainability for the medical devices sector that can be enabled via a new Quintuple Helix Hub approach that combines academia, industry, healthcare, regulators, and society to unlock real world solutions.

Ciprofloxacin-Loaded Mixed Polymeric Micelles as Antibiofilm Agents

In this work, mixed polymeric micelles (MPMs) based on a cationic poly(2-(dimethylamino)ethyl methacrylate)-b-poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA₂₉-b-PCL₇₀-b-PDMAEMA₂₉) and a non-ionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO₉₉-b-PPO₆₇-b-PEO₉₉) triblock copolymers, blended at different molar ratios, were developed. The key physicochemical parameters of MPMs, including size, size distribution, and critical micellar concentration (CMC), were evaluated. The resulting MPMs are nanoscopic with a hydrodynamic diameter of around 35 nm, and the ζ-potential and CMC values strongly depend on the MPM's composition. Ciprofloxacin (CF) was solubilized by the micelles via hydrophobic interaction with the micellar core and electrostatic interaction between the polycationic blocks, and the drug localized it, to some extent, in the micellar corona. The effect of a polymer-to-drug mass ratio on the drug-loading content (DLC) and encapsulation efficiency (EE) of MPMs was assessed. MPMs prepared at a polymer-to-drug mass ratio of 10:1 exhibited very high EE and a prolonged release profile. All micellar systems demonstrated their capability to detach pre-formed Gram-positive and Gram-negative bacterial biofilms and significantly reduced their biomass. The metabolic activity of the biofilm was strongly suppressed by the CF-loaded MPMs indicating the successful drug delivery and release. The cytotoxicity of empty and CF-loaded MPMs was evaluated. The test reveals composition-dependent cell viability without cell destruction or morphological signs of cell death.

Antibacterial, Anti-Biofilm and Pro-Migratory Effects of Double Layered Hydrogels Packaged with Lactoferrin-DsiRNA-Silver Nanoparticles for Chronic Wound Therapy

Antimicrobial resistance and biofilm formation in diabetic foot infections worsened during the COVID-19 pandemic, resulting in more severe infections and increased amputations. Therefore, this study aimed to develop a dressing that could effectively aid in the wound healing process and prevent bacterial infections by exerting both antibacterial and anti-biofilm effects. Silver nanoparticles (AgNPs) and lactoferrin (LTF) have been investigated as alternative antimicrobial and anti-biofilm agents, respectively, while dicer-substrate short interfering RNA (DsiRNA) has also been studied for its wound healing effect in diabetic wounds. In this study, AgNPs were complexed with LTF and DsiRNA via simple complexation before packaging in gelatin hydrogels. The formed hydrogels exhibited 1668% maximum swellability, with a 46.67 ± 10.33 µm average pore size. The hydrogels demonstrated positive antibacterial and anti-biofilm effects toward the selected Gram-positive and Gram-negative bacteria. The hydrogel containing AgLTF at 125 µg/mL was also non-cytotoxic on HaCaT cells for up to 72 h of incubation. The hydrogels containing DsiRNA and LTF demonstrated superior pro-migratory effects compared to the control group. In conclusion, the AgLTF-DsiRNA-loaded hydrogel possessed antibacterial, anti-biofilm, and pro-migratory activities. These findings provide a further understanding and knowledge on forming multipronged AgNPs consisting of DsiRNA and LTF for chronic wound therapy.

Increased Levels of (p)ppGpp Correlate with Virulence and Biofilm Formation, but Not with Growth, in Strains of Uropathogenic Escherichia coli

Urinary tract infections are one of the most frequent bacterial diseases worldwide. UPECs are the most prominent group of bacterial strains among pathogens responsible for prompting such infections. As a group, these extra-intestinal infection-causing bacteria have developed specific features that allow them to sustain and develop in their inhabited niche of the urinary tract. In this study, we examined 118 UPEC isolates to determine their genetic background and antibiotic resistance. Moreover, we investigated correlations of these characteristics with the ability to form biofilm and to induce a general stress response. We showed that this strain collection expressed unique UPEC attributes, with the highest representation of FimH, SitA, Aer, and Sfa factors (100%, 92.5%, 75%, and 70%, respectively). According to CRA (Congo red agar) analysis, the strains particularly predisposed to biofilm formation represented 32.5% of the isolates. Those biofilm forming strains presented a significant ability to accumulate multi-resistance traits. Most notably, these strains presented a puzzling metabolic phenotype-they showed elevated basal levels of (p)ppGpp in the planktonic phase and simultaneously exhibited a shorter generation time when compared to non-biofilm-forming strains. Moreover, our virulence analysis showed these phenotypes to be crucial for the development of severe infections in the Galleria mellonella model.

Analysis of Characteristics, Pathogens and Drug Resistance of Urinary Tract Infection Associated with Long-Term Indwelling Double-J Stent

Objective

To investigate the characteristics, pathogens and drug resistance of urinary tract infection (UTI) associated with long-term indwelling double-J stent.

Methods

The clinical data of 102 patients with urinary tract infection associated with long-term indwelling double-J stent in University-Town Hospital of Chongqing Medical University and Chongqing Traditional Chinese Medicine Hospital from September 2010 to July 2022 were collected retrospectively, and the difference between etiological characteristics were analyzed. Urine and double-J stent samples of patients were collected for pathogen identification and drug sensitivity test.

Results

A total of 102 patients, 39 (38.23%) males and 63 (61.77%) females, aged 24-72 years, with a median age of 48 years, were included in this study. Urinary calculi (40.20%) and ureteral stricture (24.50%) were the main causes of urinary tract infection associated with long-term indwelling double-J stent. Among the patients with urinary tract infection caused by double-J stent, female patients were higher than male patients (61.77% vs 38.23%). In terms of positive rate of pathogenic bacteria culture, the rate of double-J stent was higher than that of urine (67.65% vs 35.29%). The main pathogenic bacteria in urine were Escherichia coli (30.55%) of Gram negative bacteria, while the main pathogenic bacteria in double-J stent were enterococcus faecalis (27.53%) of Gram positive bacteria. The resistance rate of Gram positive bacteria in double-J stent to vancomycin, ciprofloxacin, meropenem and piperacillin/tazobactam was significantly higher than that in urine (P<0.05). The resistance rate of Gram negative bacteria in double-J stent to imipenem, cefepime, piperacillin/tazobactam, meropenem and cefoperazone/sulbactam was significantly higher than that in urine (P<0.05).

Conclusion

Double-J stent associated urinary tract infection is more common in women than in men. Escherichia coli and Enterococcus faecalis are the main pathogens, and the pathogens show strong drug resistance.

Easy and Affordable: A New Method for the Studying of Bacterial Biofilm Formation

BACKGROUND

Bacterial biofilm formation (BBF) proves itself to be in the spotlight of microbiology research due to the wide variety of infections that it can be associated with, the involvement in food spoilage, industrial biofouling and perhaps sewage treatment. However, BBF remains difficult to study due to the lack of standardization of the existing methods and the expensive equipment needed. We aim to describe a new inexpensive and easy to reproduce protocol for a 3D-printed microfluidic device that can be used to study BBF in a dynamic manner.

METHODS

We used the SolidWorks 3D CAD Software (EducationEdition 2019-2020, Dassault Systèmes, Vélizy-Villacoublay, France) to design the device and the Creality3D Ender 5 printer (Shenzhen Creality 3D Technology Co., Ltd., Shenzhen, China) for its manufacture. We cultivated strains of Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. For the biofilm evaluation we used optical coherence tomography (OCT), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and crystal violet staining technique.

RESULTS

Based on the analysis, Enterococcus faecalis seems to produce more biofilm in the first hours while Pseudomonas aeruginosa started to take the lead on biofilm production after 24 h.

CONCLUSIONS

With an estimated cost around €0.1285 for one microfluidic device, a relatively inexpensive and easy alternative for the study of BBF was developed.