River waters in Greece: A reservoir for clinically relevant extended-spectrum-β-lactamases-producing Escherichia coli

In the current study, the genotypic characteristics such as antimicrobial resistance and virulence genes, and plasmid replicons and phenotypic characteristics such as biofilm formation and antimicrobial resistance of 87 extended-spectrum beta-lactamase (ESBL)-producing E. coli (ESBL-Ec) isolated from 7 water bodies in northern Greece were investigated. Our data show a high prevalence (60.0 %) of ESBL-Ec in surface waters that exhibit high genetic diversity, suggesting multiple sources of their transmission into the aquatic environment. When evaluating the antimicrobial resistance of isolates, wide variation in their resistance profiles has been detected, with all isolates being multi-drug resistant (MDR). Regarding biofilm formation capacity and phylogenetic groups, the majority (54.0 %, 47/87) of ESBL-Ec were classified as no biofilm producers mainly assigned to phylogroup A (35.6 %; 31/87), followed by B2 (26.5 %; 23/87). PCR screening showed that a high proportion of the isolates tested positive for the blaCTX-M-1 group genes (69 %, 60/87), followed by blaTEM (55.2 %, 48/87), blaOXA (25.3 %, 22/87) and blaCTX-M-9 (17.2 %, 15/87). A subset of 28 ESBL-Ec strains was further investigated by applying whole genome sequencing (WGS), and among them, certain clinically significant sequence types were identified, such as ST131 and ST10. The corresponding in silico analysis predicted all these isolates as human pathogens, while a significant proportion of WGS-ESBL-Ec were assigned to extraintestinal pathogenic E. coli (ExPEC; 32.1 %), and urinary pathogenic E. coli (UPEC; 28.6 %) pathotypes. Comparative phylogenetic analysis, showed that the genomes of the ST131-O25:H4-H30 isolates are genetically linked to the human clinical strains. Here, we report for the first time the detection of a plasmid-mediated mobile colistin resistance gene in ESBL-Ec in Greece isolated from an environmental source. Overall, this study underlines the role of surface waters as a reservoir for antibiotic resistance genes and for presumptive pathogenic ESBL-Ec.

Does Phage Therapy Need a Pan-Phage?

The emergence of multidrug-resistant bacteria is undoubtedly one of the most serious global health threats. One response to this threat that has been gaining momentum over the past decade is 'phage therapy'. According to this, lytic bacteriophages are used for the treatment of bacterial infections, either alone or in combination with antimicrobial agents. However, to ensure the efficacy and broad applicability of phage therapy, several challenges must be overcome. These challenges encompass the development of methods and strategies for the host range manipulation and bypass of the resistance mechanisms developed by pathogenic bacteria, as has been the case since the advent of antibiotics. As our knowledge and understanding of the interactions between phages and their hosts evolves, the key issue is to define the host range for each application. In this article, we discuss the factors that affect host range and how this determines the classification of phages into different categories of action. For each host range group, recent representative examples are provided, together with suggestions on how the different groups can be used to combat certain types of bacterial infections. The available methodologies for host range expansion, either through sequential adaptation to a new pathogen or through genetic engineering techniques, are also reviewed.

Biofilm-producing antibiotic-resistant bacteria in Indian patients: a comprehensive review

For the past few years, microbial biofilms have been emerging as a significant threat to the modern healthcare system, and their prevalence and antibiotic resistance threat gradually increase daily among the human population. The biofilm has a remarkable impact in the field of infectious diseases, in particular healthcare-associated infections related to indwelling devices such as catheters, implants, artificial heart valves, and prosthetic joints. Bacterial biofilm potentially adheres to any biotic or abiotic surfaces that give specific shelter to the microbial community, making them less susceptible to many antimicrobial agents and even resistant to the immune cells of animal hosts. Around thirty clinical research reports available in PUBMED have been considered to establish the occurrence of biofilm-forming bacteria showing resistance against several regular antibiotics prescribed against infection by clinicians among Indian patients. After the extensive literature review, our observation exhibits a high predominance of biofilm formation among bacteria such as Escherichia sp., Streptococcus sp., Staphylococcus sp., and Pseudomonas sp., those are the most common biofilm-producing antibiotic-resistant bacteria among Indian patients with urinary tract infections and/or catheter-related infections, respiratory tract infections, dental infections, skin infections, and implant-associated infections. This review demonstrates that biofilm-associated bacterial infections constantly elevate in several pathological conditions along with the enhancement of the multi-drug resistance phenomenon.

The Critical Role of Intracellular Bacterial Communities in Uncomplicated Recurrent Urinary Cystitis: A Comprehensive Review of Detection Methods and Diagnostic Potential

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide and are particularly prevalent in women. Recurrent UTIs significantly diminish quality of life due to their symptoms and frequent relapses. Patients often experience immediate relapse following slightly strenuous activities or intense psychological stress. In this review, we explore why infections persist despite the advent of various treatments and suggest strategies to manage recurrent cystitis by targeting the mechanisms of adhesion and infection. Vitamin D levels and the expression of neutrophil gelatinase-associated lipocalin are linked to the recurrence of UTIs. During a UTI, bacteria employ adhesins to invade the urinary tract, adhere to urothelial cells, and then penetrate these cells, where they rapidly multiply to establish intracellular bacterial communities. Bacteria can also form quiescent intracellular reservoirs that escape immune responses and antibiotic treatments, leading to recurrence under certain conditions. The surface proteins of bacteria and D-mannose are crucial in the adhesion of bacteria to the urothelium. Understanding these processes provides valuable insights into potential therapeutic approaches that focus on preventing bacterial attachment and cluster formation. By disrupting the ability of bacteria to adhere to and form clusters on cells, we can better manage recurrent UTIs and improve patient outcomes.

Anti-quorum sensing effects of SidA protein on Escherichia coli receptors: in silico analysis

Quorum sensing enables cell-cell communication in bacteria and regulates biofilm formation. Biofilm production promotes pathogenicity of Escherichia coli and causes infections. However, antibiotic resistance limits conventional treatment efficacy against biofilm infections. Quorum quenching offers an alternative by disrupting quorum sensing signals. Allicin, extracted from garlic, possesses antimicrobial and anti-quorum sensing properties. This study employed molecular docking and dynamics simulations to investigate allicin's interaction with the E. coli quorum sensing system, specifically targeting the cytoplasmic SidA receptor protein. SidA binds to N-acyl-homoserine lactone ligands and regulates quorum sensing in E. coli. The crystal structure of SidA was obtained from the PDB. Molecular docking revealed that allicin competitively binds to the ligand-binding pocket of SidA. Simulations analyzed the effects of allicin binding on SidA stability and affinity for N-acyl-homoserine lactones over 200 ns. Parameters like RMSD, RMSF, and hydrogen bonding indicated SidA was more stable when bound to allicin compared to unbound. Binding free energies suggested allicin reduced SidA's affinity for native ligands. Therefore, allicin binding to SidA alters its conformation and inhibits interaction with N-acyl-homoserine lactones, disrupting quorum sensing signaling and biofilm production in E. coli.Communicated by Ramaswamy H. Sarma.

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.

Characterization of Salmonella enterica Biofilms and Antibiofilm Effect of Carvacrol and 2-Aminobenzimidazole

Biofilm-associated foodborne Salmonella infections in poultry have become increasingly challenging for veterinarians, particularly in developing countries, and warrant thorough investigation. We assessed the biofilm-forming tendency of poultry isolates of Salmonella enterica, namely Salmonella Typhimurium (n = 23), Salmonella Infantis (n = 28), and Salmonella Heidelberg (n = 18), in nutrient-rich Rappaport-Vassiliadis Soya (RVS) peptone broth and nutrient-deficient diluted Tryptone Soya Broth (TSB). Seven of the tested isolates exhibited moderate biofilm formation in diluted TSB, whereas two showed such formation in RVS. In addition, the Congo red agar assay revealed curli and cellulose production in seven isolates. Fourteen specific biofilm-associated genes were analyzed identifying sdiA and seqA to be the most prevalent (100%), and glyA the least prevalent (69.5%). The prevalence of the genes bcsA and csgA was significantly lower in moderate and weak biofilm formers, respectively, as compared with nonbiofilm formers in RVS peptone broth. Furthermore, the compounds carvacrol and 2-aminobenzimidazole (2-ABI) effectively inhibited biofilm formation by Salmonella serovars in RVS peptone and TSB media, respectively. Whereas the antibiofilm activity of 2-ABI against Salmonella has not been reported previously, we determined its most effective concentration at 1.5 mM among tested antibiofilm treatments. These findings indicate that Salmonella strains prevalent in poultry farms have the potential to form biofilms, and the tested compounds should be further explored as supportive or alternative antimicrobials.

Impact of antibiotic pharmacokinetics in urine on recurrent bacteriuria following treatment of complicated urinary tract infections

The clinical relevance of bacteriuria following antibiotic treatment of complicated urinary tract infections in clinical trials remains controversial. We evaluated the impact of urine pharmacokinetics on the timing of recurrent bacteriuria in a recently completed trial that compared oral tebipenem pivoxil hydrobromide to intravenous ertapenem. The urinary clearance and urine dwell time of ertapenem were prolonged relative to tebipenem and were associated with a temporal difference in the repopulation of bladder urine with bacteria following treatment, potentially confounding the assessment of efficacy.

Insights into the antimicrobial properties of a cationic steroid and antibiofilm performance in PDMS-based coatings to potentially treat urinary infections

Currently, multidrug-resistant (MDR) infections are one of the most important threats, driving the search for new antimicrobial compounds. Cationic peptide antibiotics (CPAs) and ceragenins (CSAs) contain in their structures cationic groups and adopt a facially amphiphilic conformation, conferring the ability to permeate the membranes of bacteria and fungi. Keeping these features in mind, an amine steroid, DOCA-NH2, was found to be active against reference strains and MDR isolates of Gram-positive Enterococcus faecalis and Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa. The compound was active against all the tested microorganisms, having bactericidal and fungicidal activity, displaying minimal inhibitory concentrations (MICs) between 16 and 128 μg mL-1. No synergy with clinically relevant antibacterial drugs was found. However, the compound was able to completely inhibit the biofilm formation of bacteria exposed to the MIC of the compound. For E. coli and E. faecalis, inhibition of biofilm formation occurred at half the MIC. Besides, DOCA-NH2 inhibited the dimorphic transition of Candida albicans at concentrations 4 times lower than the MIC, and can reduce the microorganism virulence and biofilm formation was significantly reduced at both MIC and half the MIC. Polydimethylsiloxane-based coatings containing DOCA-NH2 (0.5, 1.0, and 1.5 wt%) were prepared and tested against the E. coli biofilm formation under hydrodynamic conditions similar to those prevailing in ureteral stents. A biofilm reduction of approximately 80% was achieved when compared to the control.

Organic Matrix Derived from Host-Microbe Interplay Contributes to Pathological Renal Biomineralization

Matrix stones are a rare form of kidney stones. They feature a high percentage of hydrogel-like organic matter, and their formation is closely associated with urinary tract infections. Herein, comprehensive materials and biochemical approaches were taken to map the organic-inorganic interface and gather insights into the host-microbe interplay in pathological renal biomineralization. Surgically extracted soft and slimy matrix stones were examined using micro-X-ray computed tomography and various microspectroscopy techniques. Higher-mineral-density laminae were positive for calcium-bound Alizarin red. Lower-mineral-density laminae revealed periodic acid-Schiff-positive organic filamentous networks of varied thickness. These organic filamentous networks, which featured a high polysaccharide content, were enriched with zinc, carbon, and sulfur elements. Neutrophil extracellular traps (NETs) along with immune response-related proteins, including calprotectin, myeloperoxidase, CD63, and CD86, also were identified in the filamentous networks. Expressions of NETs and upregulation of polysaccharide-rich mucin secretion are proposed as a part of the host immune defense to "trap" pathogens. These host-microbe derived organic matrices can facilitate heterogeneous nucleation and precipitation of inorganic particulates, resulting in macroscale aggregates known as "matrix stones". These insights into the plausible aggregation of constituents through host-microbe interplay underscore the unique "double-edged sword" effect of the host immune response to pathogens and the resulting renal biominerals.

Emerging evidence-based innovative approaches to control catheter-associated urinary tract infection: a review

Healthcare settings have dramatically advanced the latest medical devices, such as urinary catheters (UC) for infection, prevention, and control (IPC). The continuous or intermittent flow of a warm and conducive (urine) medium in the medical device, the urinary catheter, promotes the formation of biofilms and encrustations, thereby leading to the incidence of CAUTI. Additionally, the absence of an innate immune host response in and around the lumen of the catheter reduces microbial phagocytosis and drug action. Hence, the review comprehensively overviews the challenges posed by CAUTI and associated risks in patients' morbidity and mortality. Also, detailed, up-to-date information on the various strategies that blended/tailored the surface properties of UC to have anti-fouling, biocidal, and anti-adhesive properties to provide an outlook on how they can be better managed with futuristic solutions.

Reduction of biofilm formation of Escherichia coli by targeting quorum sensing and adhesion genes using the CRISPR/Cas9-HDR approach, and its clinical application on urinary catheter

BACKGROUND

Escherichia coli is a common cause of biofilm-associated urinary tract infections (UTIs). Biofilm formation in E. coli is responsible for various indwelling medical device-associated infections, including catheter-associated urinary tract infections (CAUTIs). This study aimed to reduce biofilm formation of E. coli ATCC 25922 by knocking out genes involved in quorum sensing (QS) (luxS) and adhesion (fimH and bolA) using the CRISPR/Cas9-HDR approach.

METHOD

Single-guide RNAs (sgRNAs) were designed to target luxS, fimH and bolA genes. Donor DNA for homologous recombination was constructed to provide accurate repairs of double-strand breaks (DSBs). A biofilm quantification assay (crystal violet assay) was performed to quantify the biofilm formation of mutant and wild-type strains. Morphological changes in biofilm architecture were confirmed by scanning electron microscopy (SEM). Further application of the biofilm formation of mutant and wild-type strains on urinary catheter was tested.

RESULTS

Crystal violet assay showed that the biofilm formation of ΔfimH, ΔluxS, and ΔbolA strains was significantly reduced compared to the wild-type strain (P value < 0.001). The percentage of biofilm reduction of mutant strains was as follows: ΔluxS1 77.51 %, ΔfimH1 78.37 %, ΔfimH2 84.17 %, ΔbolA1 78.24 %, and ΔbolA2 75.39 %. Microscopic analysis showed that all mutant strains lack extracellular polymeric substances (EPS) production compared to the wild-type strain, which was embedded in its EPS matrix. The adherence, cell aggregation, and biofilm formation of wild-type strain on urinary catheters were significantly higher compared to ΔfimH, ΔluxS and ΔbolA strains.

CONCLUSION

Altogether, our results demonstrated that the knockout of luxS, fimH, and bolA genes reduced EPS matrix production, which is considered the main factor in the development, maturation, and maintenance of the integrity of biofilm. This pathway could be a potential strategy to disrupt E. coli biofilm-associated UTIs. This study suggests that CRISPR/Cas9-HDR system may provide an efficient and site-specific gene editing approach that exhibits a possible antibiofilm strategy through intervention with the QS mechanism and adhesion property to suppress biofilm formation associated with UTI catheter infections.

Differences in Virulence Factors and Antimicrobial Susceptibility of Uropathogenic Enterococcus spp. Strains in a Rural Area of Uganda and a Spanish Secondary Hospital

Enterococcus faecalis and Enterococcus faecium have become two of the most important agents of nosocomial diseases due to their constantly growing resistance. Enterococcal infections are associated with biofilms, which are intrinsically sensitive to antimicrobials. The main goal of this study was to compare and relate their capacity to form biofilm and their antimicrobial sensitivity, as well as their virulence factors and their implicated genes, of strains isolated from patients with urinary tract infection (UTI) in a rural hospital in Uganda and a secondary hospital in Spain. A prospective study was conducted with 104 strains of E. faecalis and E. faecium isolated from patients with suspected UTI and who presented leukocyturia at the Saint Joseph Kitgum hospital (Uganda) and at the Hospital Universitario Principe de Asturias (Spain). All microorganisms were identified in Spain by MALDI-TOF mass spectrometry. Antimicrobial susceptibility studies were carried out using the Vitek^® 2 system (Biomériux, France). The biofilm formation capacity was studied by photospectrometry. Phenotypic and genotypic virulence factors were studied in all cases by PCR or expression techniques. In Uganda, we found a higher incidence of E. faecium (65.3%, n = 32), contrary to the situation found in Spain where most of the bacteria found belonged to E. faecalis (92.7%, n = 51). All E. faecalis strains were found to have very low levels of resistance to ampicillin, imipenem, and nitrofurantoin. However, E. faecium exhibited more than 25% resistance to these antibiotics. Although the esp gene has been shown in the results obtained to be an important initial agent in biofilm formation, we have also demonstrated in this study the intervention of other genes when esp is not present, such as the ace1 gene. No statistically significant relationships were found between the presence of agg and gelE genes and increased biofilm formation. The significant difference between the incidence of E. faecalis and E. faecium and biofilm formation, between samples from Spain and Uganda, shows us very different profiles between countries.

Antibiotic Resistance Profile, Biofilm Formation Ability, and Virulence Factors Analysis of Three Staphylococcus spp. Isolates From Urine

Background Staphylococcus spp. is one of the most causative agents of urinary tract infections (UTIs). This study aimed to investigate the antibiotic resistance profile and the virulence factors, including the biofilm formation ability of Staphylococcus spp. isolates from urine. Methodology The agar disk diffusion method was used to test the susceptibility of Staphylococcus isolates to ten antibiotics. The biofilm formation ability was determined using the safranin microplate-based method, and the phospholipase, esterase, and hemolysin activities were assessed by the agar plate method. Results During the study period, a prevalence of 18.12% of urinary tract infections caused by the identified Staphylococci was obtained. All the isolated Staphylococcus aureus and S. epidermidis were resistant to cefazolin. Multi-drug resistance (MDR) was recorded in 80.01%, 81.49%, and 76.20% of S. aureus, S. epidermidis, and S. saprophyticus isolates, respectively. Most of the isolates were moderate biofilm formers, while 44.44%, 31.75%, and 30.16% were positive for phospholipase, esterase, and hemolysin activities, respectively. No relevant correlations were observed between the ability of biofilm formation and the resistance to antibiotics or the expression of virulence factors investigated. Conclusion This study shows that Staphylococcus spp. isolates from patients with clinical manifestations of UTIs expressed a high degree of virulence factors, including the ability of biofilm formation, and exhibited multi-drug resistance to the majority of antimicrobials commonly used for the treatment of Staphylococcal infections.

Short Peripheral Venous Catheters Contamination and the Dangers of Bloodstream Infection in Portugal: An Analytic Study

Peripheral venous catheters (PVCs) are the most used vascular access devices in the world. However, failure rates remain considerably high, with complications such as PVC-related infections posing significant threats to patients’ well-being. In Portugal, studies evaluating the contamination of these vascular medical devices and characterizing the associated microorganisms are scarce and lack insight into potential virulence factors. To address this gap, we analyzed 110 PVC tips collected in a large tertiary hospital in Portugal. Experiments followed Maki et al.’s semi-quantitative method for microbiological diagnosis. Staphylococcus spp. were subsequently studied for the antimicrobial susceptibility profile by disc diffusion method and based on the cefoxitin phenotype, were further classified into strains resistant to methicillin. Screening for the mecA gene was also done by a polymerase chain reaction and minimum inhibitory concentration (MIC)-vancomycin as determined by E-test, proteolytic and hemolytic activity on skimmed milk 1% plate and blood agar, respectively. The biofilm formation was evaluated on microplate reading through iodonitrotetrazolium chloride 95% (INT). Overall, 30% of PVCs were contaminated, and the most prevalent genus was Staphylococcus spp., 48.8%. This genus presented resistance to penicillin (91%), erythromycin (82%), ciprofloxacin (64%), and cefoxitin (59%). Thus, 59% of strains were considered resistant to methicillin; however, we detected the mecA gene in 82% of the isolates tested. Regarding the virulence factors, 36.4% presented α-hemolysis and 22.7% β-hemolysis, 63.6% presented a positive result for the production of proteases, and 63.6% presented a biofilm formation capacity. Nearly 36.4% were simultaneously resistant to methicillin and showed expression of proteases and/or hemolysins, biofilm formation, and the MIC to vancomycin were greater than 2 µg/mL. Conclusion: PVCs were mainly contaminated with Staphylococcus spp., with high pathogenicity and resistance to antibiotics. The production of virulence factors strengthens the attachment and the permanence to the catheter’s lumen. Quality improvement initiatives are needed to mitigate such results and enhance the quality and safety of the care provided in this field.

Combination drug strategies for biofilm eradication using synthetic and natural agents in KAPE pathogens

Antibiotic resistance is a global threat caused by factors such as overuse of antibiotics, lack of awareness, development of biofilms etc. World Health Organization released a list of global priority pathogens which consisted of 12 species of bacteria categorized as expressing critical, high and medium resistance. Several Gram-negative and Gram-positive species are known to cause wide varieties of infections and have become multidrug or extremely drug resistant. Pathogens causing infections associated with invasive medical devices are biofilm producers and hence their treatment becomes difficult due to a structurally stable matrix which prevents antibiotics from penetrating the biofilm and thereby showing its effects. Factors contributing to tolerance are inhibition of penetration, restricted growth and activation of biofilm genes. Combination drug therapies has also shown potential to eradicate biofilm infections. A combination of inhaled Fosfomycin/tobramycin antibiotic strategy has been effective against Gram-negative as well as Gram positive organisms. Along with antibiotics, use of natural or synthetic adjuvants shows promising effects to treat biofilm infections. Fluroquinolone activity on biofilms is disrupted by low oxygen tension in the matrix, a strategy known as hyperbaric oxygen treatment that can enhance efficacy of antibiotics if well optimized. Adjuvants such as Ethylenediaminetetraacetic acid (EDTA), Sodium Dodecyl Sulphate (SDS) and chlorhexidine act by killing non-growing microbial cells aggregated on the inner layer of the biofilm. This review aims to list down current combination therapies used against Gram-negative and Gram-positive biofilm forming pathogens and brief about comparison of combination drugs and their efficacies.

The role of nanocomposites against biofilm infections in humans

The use of nanomaterials in several fields of science has undergone a revolution in the last few decades. It has been reported by the National Institutes of Health (NIH) that 65% and 80% of infections are accountable for at least 65% of human bacterial infections. One of their important applications in healthcare is the use of nanoparticles (NPs) to eradicate free-floating bacteria and those that form biofilms. A nanocomposite (NC) is a multiphase stable fabric with one or three dimensions that are much smaller than 100 nm, or systems with nanoscale repeat distances between the unique phases that make up the material. Using NC materials to get rid of germs is a more sophisticated and effective technique to destroy bacterial biofilms. These biofilms are refractory to standard antibiotics, mainly to chronic infections and non-healing wounds. Materials like graphene and chitosan can be utilized to make several forms of NCs, in addition to different metal oxides. The ability of NCs to address the issue of bacterial resistance is its main advantage over antibiotics. This review highlights the synthesis, characterization, and mechanism through which NCs disrupt Gram-positive and Gram-negative bacterial biofilms, and their relative benefits and drawbacks. There is an urgent need to develop materials like NCs with a larger spectrum of action due to the rising prevalence of human bacterial diseases that are multidrug-resistant and form biofilms.

Antibiotic Resistance and Biofilm Formation in Enterococcus spp. Isolated from Urinary Tract Infections

Background: A urinary tract infection (UTI) resulting from multidrug-resistant (MDR) enterococci is a common disease with few therapeutic options. About 15% of urinary tract infections are caused by biofilm-producing Enterococcus spp. Therefore, the objective of this study was to identify the MDR enterococci associated with UTIs and assess their potential to produce biofilms. Methods: Thirty Enterococcus isolates were obtained from urine samples collected from UTI patients at King Abdulaziz Specialist Hospital in Taif, Saudi Arabia. The antimicrobial resistance profiles of the isolates were evaluated using disk diffusion techniques against 15 antimicrobial agents. Two techniques, Congo red agar (CRA) and a microtiter plate (MTP), were used to assess the potential of the isolates to produce biofilms. The enterococcal isolates were screened for biofilm-related genes, esp; ebpA; and ebpB, using the PCR method. Results: The molecular identification of the collected bacteria revealed the presence of 73.3% Enterococcus faecalis and 26.6% Enterococcus faecium. The antibiotic susceptibility test revealed that all the tested Enterococcus spp. were resistant to all antimicrobials except for linezolid and tigecycline. Additionally, by employing the CRA and MTP techniques, 76.6% and 100% of the Enterococcus isolates were able to generate biofilms, respectively. In terms of the association between the antibiotic resistance and biofilm’s formation, it was observed that isolates capable of creating strong biofilms were extremely resistant to most of the antibiotics tested. The obtained data showed that all the tested isolates had biofilm-encoding genes. Conclusions: Our research revealed that the biofilm-producing enterococci bacteria that causes urinary tract infections were resistant to antibiotics. Therefore, it is necessary to seek other pharmacological treatments if antibiotic medicine fails.

Non-invasive biomedical sensors for early detection and monitoring of bacterial biofilm growth at the point of care

Bacterial infections have long been a serious global health issue. Biofilm formation complicates matters even more. The biofilm's extracellular polymeric substances (EPSs) matrix protects bacteria from the host's immune responses, yielding strong adhesion and drug resistance as the biofilm matures. Early bacterial biofilm detection and bacterial biofilm growth monitoring are crucial to treating biofilm-associated infections. Current detection methods are highly sensitive but not portable, are time-consuming, and require expensive equipment and complex operating procedures, limiting their use at the point of care. Therefore, there is an urgent need to develop affordable, on-body, and non-invasive biomedical sensors to continuously monitor and detect early biofilm growth at the point of care through personalized telemedicine. Herein, recent advances in developing non-invasive biomedical sensors for early detection and monitoring bacterial biofilm growth are comprehensively reviewed. First, biofilm's life cycle and its impact on the human body, such as biofilm-associated disease and infected medical devices, are introduced together with the challenges of biofilm treatment. Then, the current methods used in clinical and laboratory settings for biofilm detection and their challenges are discussed. Next, the current state of non-invasive sensors for direct and indirect detection of bacterial biofilms are summarized and highlighted with the detection parameters and their design details. Finally, commercially available products, challenges of current devices, and the further trend in biofilm detection sensors are discussed.

Effect of Ciprofloxacin-Loaded Niosomes on Escherichia coli and Staphylococcus aureus Biofilm Formation

Infections caused by bacterial biofilms represent a global health problem, causing considerable patient morbidity and mortality in addition to an economic burden. Escherichia coli, Staphylococcus aureus, and other medically relevant bacterial strains colonize clinical surfaces and medical devices via biofilm in which bacterial cells are protected from the action of the immune system, disinfectants, and antibiotics. Several approaches have been investigated to inhibit and disperse bacterial biofilms, and the use of drug delivery could represent a fascinating strategy. Ciprofloxacin (CIP), which belongs to the class of fluoroquinolones, has been extensively used against various bacterial infections, and its loading in nanocarriers, such as niosomes, could support the CIP antibiofilm activity. Niosomes, composed of two surfactants (Tween 85 and Span 80) without the presence of cholesterol, are prepared and characterized considering the following features: hydrodynamic diameter, ζ-potential, morphology, vesicle bilayer characteristics, physical-chemical stability, and biological efficacy. The obtained results suggest that: (i) niosomes by surfactants in the absence of cholesterol are formed, can entrap CIP, and are stable over time and in artificial biological media; (ii) the CIP inclusion in nanocarriers increase its stability, with respect to free drug; (iii) niosomes preparations were able to induce a relevant inhibition of biofilm formation.

Ceragenin CSA-13 displays high antibacterial efficiency in a mouse model of urinary tract infection

Ceragenins (CSAs) are synthetic, lipid-based molecules that display activities of natural antimicrobial peptides. Previous studies demonstrated their high in vitro activity against pathogens causing urinary tract infections (UTIs), but their efficiency in vivo was not explored to date. In this study, we aimed to investigate the bactericidal efficiency of ceragenins against E. coli (Xen14 and clinical UPEC strains) isolates both in vitro and in vivo, as well to explore CSA-13 biodistribution and ability to modulate nanomechanical alterations of infected tissues using animal model of UTI. CSA-44, CSA-131 and particularly CSA-13 displayed potent bactericidal effect against tested E. coli strains, and this effect was mediated by induction of oxidative stress. Biodistribution studies indicated that CSA-13 accumulates in kidneys and liver and is eliminated with urine and bile acid. We also observed that ceragenin CSA-13 reverses infection-induced alterations in mechanical properties of mouse bladders tissue, which confirms the preventive role of CSA-13 against bacteria-induced tissue damage and potentially promote the restoration of microenvironment with biophysical features unfavorable for bacterial growth and spreading. These data justify the further work on employment of CSA-13 in the treatment of urinary tract infections.

Catheter-associated urinary tract infections: Etiological analysis, biofilm formation, antibiotic resistance, and a novel therapeutic era of phage

Urinary tract infection (UTI) caused by uropathogens has put global public health at its utmost risk, especially in developing countries where people are unaware of personal hygiene and proper medication. In general, the infection frequently occurs in the urethra, bladder, and kidney, as reported by the physician. Moreover, many UTI patients whose acquired disorder from the hospital or health-care center has been addressed previously have been referred to as catheter-associated UTI (CAUTI). Meanwhile, the bacterial biofilm triggering UTI is another critical issue, mostly by catheter insertion. In most cases, the biofilm inhibits the action of antibiotics against the UTI-causing bacteria. Therefore, new therapeutic tools should be implemented to eliminate the widespread multidrug resistance (MDR) UTI-causing bacteria. Based on the facts, the present review emphasized the current status of CAUTI, its causative agent, clinical manifestation, and treatment complications. This review also delineated a model of phage therapy as a new therapeutic means against bacterial biofilm-originated UTI. The model illustrated the entire mechanism of destroying the extracellular plyometric substances of UTI-causing bacteria with several enzymatic actions produced by phage particles. This review will provide a complete outline of CAUTI for the general reader and create a positive vibe for the researchers to sort out alternative remedies against the CAUTI-causing MDR microbial agents.

A review on biofilms and the currently available antibiofilm approaches: Matrix-destabilizing hydrolases and anti-bacterial peptides as promising candidates for the food industries

Biofilms are communities of microorganisms that can be harmful and/or beneficial, depending on location and cell content. Since in most cases (such as the formation of biofilms in laboratory/medicinal equipment, water pipes, high humidity-placed structures, and the food packaging machinery) these bacterial and fungal communities are troublesome, researchers in various fields are trying to find a promising strategy to destroy or slow down their formation. In general, anti-biofilm strategies are divided into the plant-based and non-plant categories, with the latter including nanoparticles, bacteriophages, enzymes, surfactants, active peptides and free fatty acids. In most cases, using a single strategy will not be sufficient to eliminate biofilm, and consequently, two or more strategies will inevitably be used to deal with this unwanted phenomenon. According to the analysis of potential biofilm inhibition strategies, the best option for the food industry would be the use of hydrolase enzymes and peptides extracted from natural sources. This article represents a systematic review of the previous efforts made in these directions.

Assessment of Bacterial Isolates from the Urine Specimens of Urinary Tract Infected Patient

Urinary tract infections (UTIs) maintained a serious public health concern, as did the growth in antibiotic resistance both between uropathogenic microorganisms. A regular assessment of the microbiological agents that cause UTIs, as well as their antimicrobial resistance, is essential for a tailored empirical antibiotic response. Knowing the variables that cause UTIs can help you intervene quickly and simply to get the condition under control. The most common infecting species in acute infection is Escherichia coli (E. coli). To strengthen infection control strategies, it is necessary to know the prevalence and location of UTI. The goal of this research is to measure the frequency of microorganisms isolated from patients with UTIs as well as the antimicrobial sensitivity characteristics of Gram-negative bacteria. The purpose of this research has been to evaluate the frequency of UTIs by extracting and characterizing the various bacterial etiological organisms, as well as to assess the factors linked to UTIs. The goal of this research is to identify, characterize, and establish the antibiotic susceptibility patterns of bacteria linked to urinary tract infections. Fresh collected urine specimen was taken from inpatients or outpatients in UTI cases and bacteriologically tested using conventional microbiological methods. The Kirby-Bauer disc diffusion method was used to create the antibiogram. Staphylococcus saprophyticus, Staphylococcus aureus (28%), and Escherichia coli (24.6%) were the most common isolates (20%). The evaluated agents' antibacterial activity was all in the following order: cefixime, ciprofloxacin, augmentin, gentamicin, ceftazidime, nitrofurantoin, ofloxacin, and cefuroxime. It was discovered that each and every one of the microbes exhibited varied degrees of resistance to the antibiotics nitrofurantoin, ciprofloxacin, and ofloxacin. Every type of bacteria, with the exception of those belonging to the genus Streptococcus, has a Multiple Antibiotic Resistance Index (MARI) that is more than 0.2. The first-line therapies for urinary tract infections (UTIs) in the region would consist of ciprofloxacin, ofloxacin, and nitrofurantoin. Lower urinary tract infections almost never result in problems if they are diagnosed and treated as soon as possible and in the correct manner. However, if treatment is not sought, a urinary tract infection can lead to serious complications.

Enterococcus faecalis Antagonizes Pseudomonas aeruginosa Growth in Mixed-Species Interactions

Enterococcus faecalis is often coisolated with Pseudomonas aeruginosa in polymicrobial biofilm-associated infections of wounds and the urinary tract. As a defense strategy, the host innately restricts iron availability at infection sites. Despite their coprevalence, the polymicrobial interactions of these two species in biofilms and under iron-restricted conditions remain unexplored. Here, we show that E. faecalis inhibits P. aeruginosa growth within biofilms when iron is restricted. E. faecalis lactate dehydrogenase (ldh1) gives rise to l-lactate production during fermentative growth. We find that an E. faecalis ldh1 mutant fails to inhibit P. aeruginosa growth. Additionally, we demonstrate that ldh1 expression is induced under iron-restricted conditions, resulting in increased lactic acid exported and, consequently, a reduction in local environmental pH. Together, our results suggest that E. faecalis synergistically inhibits P. aeruginosa growth by decreasing environmental pH and l-lactate-mediated iron chelation. Overall, this study emphasizes the importance of the microenvironment in polymicrobial interactions and how manipulating the microenvironment can impact the growth trajectory of bacterial communities. IMPORTANCE Many infections are polymicrobial and biofilm-associated in nature. Iron is essential for many metabolic processes and plays an important role in controlling infections, where the host restricts iron as a defense mechanism against invading pathogens. However, polymicrobial interactions between pathogens are underexplored under iron-restricted conditions. Here, we explore the polymicrobial interactions between commonly coisolated E. faecalis and P. aeruginosa within biofilms. We find that E. faecalis modulates the microenvironment by exporting lactic acid which further chelates already limited iron and also lowers the environmental pH to antagonize P. aeruginosa growth under iron-restricted conditions. Our findings provide insights into polymicrobial interactions between bacteria and how manipulating the microenvironment can be taken advantage of to better control infections.

Urinary Tract Infections Caused by Uropathogenic Escherichia coli Strains—New Strategies for an Old Pathogen

Urinary tract infections (UTIs) are among the most common infections worldwide. Uropathogenic Escherichia coli (UPECs) are the main causative agent of UTIs. UPECs initially colonize the human host adhering to the bladder epithelium. Adhesion is followed by the bacterial invasion of urothelial epithelial cells where they can replicate to form compact aggregates of intracellular bacteria with biofilm-like properties. UPEC strains may persist within epithelial urothelial cells, thus acting as quiescent intracellular bacterial reservoirs (QIRs). It has been proposed that host cell invasion may facilitate both the establishment and persistence of UPECs within the human urinary tract. UPEC strains express a variety of virulence factors including fimbrial and afimbrial adhesins, invasins, iron-acquisition systems, and toxins, which cooperate to the establishment of long lasting infections. An increasing resistance rate relative to the antibiotics recommended by current guidelines for the treatment of UTIs and an increasing number of multidrug resistant UPEC isolates were observed. In order to ameliorate the cure rate and improve the outcomes of patients, appropriate therapy founded on new strategies, as alternative to antibiotics, needs to be explored. Here, we take a snapshot of the current knowledge of coordinated efforts to develop innovative anti-infective strategies to control the diffusion of UPECs.

Loss of β-Ketoacyl Acyl Carrier Protein Synthase III Activity Restores Multidrug-Resistant Escherichia coli Sensitivity to Previously Ineffective Antibiotics

Gram-negative pathogens are a major concern for global public health due to increasing rates of antibiotic resistance and the lack of new drugs. A major contributing factor toward antibiotic resistance in Gram-negative bacteria is their formidable outer membrane, which acts as a permeability barrier preventing many biologically active antimicrobials from reaching the intracellular targets and thus limiting their efficacy.

Biofilm and Gene Expression Characteristics of the Carbapenem-Resistant Enterobacterales, Escherichia coli IMP, and Klebsiella pneumoniae NDM-1 Associated with Common Bacterial Infections

In light of the limited therapeutic options with Carbapenem-Resistant Enterobacterales (CRE) infections, understanding the bacterial risk factors, such as biofilm formation and related gene expression of CRE, is vital. This study investigates the biofilm formation and biofilm-related gene expression of two enteric Enterobacterales with major CR determinants Escherichia coli IMP and Klebsiella pneumoniae NDM-1, which were seen in high prevalence in most common bacterial infections over the past few years. To our knowledge, this is the first study that demonstrated the relationship between biofilm formation and the related gene expression, to understand the potential molecular mechanisms during the biofilm formation in CRE. Biofilms were quantified by tissue culture plate assay at the stages of the biofilm development: initial attachment (6 h), microcolony formation (12 h), maturation (24 h), and dispersion (48 h). In a dispersion, event bacteria detach without any mechanical means and colonise another area. To investigate the influence of different growth conditions on biofilm formation, biofilms were quantified under different growth conditions. In parallel, quantitative real-time PCR (qPCR) assessed the biofilm-related gene expression of a cluster of genes, including biofilm maturation, quorum sensing, stress survival, and antibiotic resistance. Structural changes during biofilm development were assessed via confocal laser scanning microscopy (CLSM). We observed that the biofilm formation of CRE is correlated with the biofilm development stages, with maximum biofilm observed at 24 h at the maturation stage. Our data also showed that biofilm growth, under the condition tested, is the major factor influencing the variability of biofilm gene expression quantification assays. qPCR analyses have demonstrated that the expression of biofilm-related genes is highly correlated with phenotypic biofilm development, and these findings can be further expanded to understand the variation in regulation of such genes in these significant CRE pathogens. Our study demonstrated that both CRE strains, E. coli IMP and K. pneumoniae NDM-1, are high biofilm formers, and genes involved in biofilm development are upregulated during biofilm growth. The characteristic of the increased biofilm formation with the upregulation of antibiotic-resistant and biofilm-related genes indicates the successful pathogenic role of biofilms of these selected CRE and is attributed to their multi-drug resistance ability and successful dissemination of CRE in common bacterial infections.

Targeting Microbial Bio-film: an Update on MDR Gram-Negative Bio-film Producers Causing Catheter-Associated Urinary Tract Infections

In every age group, urinary tract infection (UTI) is found as a major recurrence infectious disorder. Bio-films produced by bacteria perform a vital role in causing infection in the tract of the urinary system, leading to recurrences and relapses. The purpose of this review is to present the role and mechanism of bio-film producing MDR Gram-negative bacteria causing UTI, their significance, additionally the challenges for remedy and prevention of catheter-associated UTI. This work appreciates a new understanding of bio-film producers which are having multi-drug resistance capability and focuses on the effect and control of bio-film producing uropathogenic bacteria related to catheterization. We have tried to analyze approaches to target bio-film and reported phytochemicals with anti-bio-film activity also updated on anti-bio-film therapy.

Validated In Silico Model for Biofilm Formation in Escherichia coli

Using Escherichia coli as the representative biofilm former, we report here the development of an in silico model built by simulating events that transform a free-living bacterial entity into self-encased multicellular biofilms. Published literature on ∼300 genes associated with pathways involved in biofilm formation was curated, static maps were created, and suitably interconnected with their respective metabolites using ordinary differential equations. Precise interplay of genetic networks that regulate the transitory switching of bacterial growth pattern in response to environmental changes and the resultant multicomponent synthesis of the extracellular matrix were appropriately represented. Subsequently, the in silico model was analyzed by simulating time-dependent changes in the concentration of components by using the R and python environment. The model was validated by simulating and verifying the impact of key gene knockouts (KOs) and systematic knockdowns on biofilm formation, thus ensuring the outcomes were comparable with the reported literature. Similarly, specific gene KOs in laboratory and pathogenic E. coli were constructed and assessed. MiaA, YdeO, and YgiV were found to be crucial in biofilm development. Furthermore, qRT-PCR confirmed the elevation of expression in biofilm-forming clinical isolates. Findings reported in this study offer opportunities for identifying biofilm inhibitors with applications in multiple industries. The application of this model can be extended to the health care sector specifically to develop novel adjunct therapies that prevent biofilms in medical implants and reduce emergence of biofilm-associated resistant polymicrobial-chronic infections. The in silico framework reported here is open source and accessible for further enhancements.

Genetic Diversity, Carbapenem Resistance Genes, and Biofilm Formation in UPEC Isolated from Patients with Catheter-Associated Urinary Tract Infection in North of Iran

BACKGROUND

Infections due to carbapenem-resistant Enterobacteriaceae (CRE) are associated in patients with urinary catheters alarming rate of emergency status. The aim of this study is to investigate the molecular causes of carbapenem resistance among UPEC as well as antimicrobial resistance trends. Additionally, the potential of isolates to produce biofilms, in addition to their clonal and genetic diversity, was investigated. Material and Methods. A cross-sectional study was accomplished on a collection of 76 non-duplicate UPEC isolates obtained from CAUTIs from May 2021 to September 2021. The modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM) test was performed for the detection of carbapenemase and metallo-beta-lactamase activity. Also, the presence of carbapenemase genes was determined using PCR assays. In 96-well microtiter plates, biofilm development was evaluated. ERIC-PCR was used to investigate the clonal and genetic variety of isolates.

RESULTS

A total of 76 confirmed UPEC isolates were obtained from patients mentioned to teaching hospitals in Babol, Iran. The results of antibiotic susceptibility testing revealed a high rate of antibiotic resistance against nalidixic acid (81.6%) and trimethoprim-sulfamethoxazole (80.3%). Among UPEC isolates, 63.2% and 13.2% of UPEC isolates were positive for MBL production. The frequencies of the studied genes are in order of bla _NDM (14.5%), bla _OXA-23 (2.6%), and bla _OXA-48 (2.6%). Forty-two isolates (55.3%) were positive for biofilm formation. ERIC-PCR revealed that UPEC isolates could be categorized into nine clusters A-I and five isolates were categorized as a singleton.

CONCLUSION

The high prevalence of MDR and carbapenemase-producing isolates among the UPEC strain in this investigation is concerning. Moreover, the bla _NDM was the most frequent cause of producing metallo-beta-lactamase and carbapenemase. Also, analysis revealed a partial genetic similarity among the studied isolates, indicating that the same UPEC clones may have spread to other hospital units.

Biofilm Matrix Formation in Human: Clinical Significance, Diagnostic Techniques, and Therapeutic Drugs

Context: Some recent reports have indicated that almost 80% of clinical infections in humans have biofilm origin and impose additional healthcare costs. This study was an updated review of extracellular polymeric substance matrix (Biofilm) formation in humans and elaborated on its clinical significance, diagnosis, and therapeutic approaches. Evidence Acquisition: This narrative study reviewed the most recent information on the significance of microbial biofilm formation in clinical settings, common biofilm-producing bacterial species, its diagnosis, antibiotic drug resistance, and new approaches to the treatment of infections associated with biofilm formation. Results: Evidence indicated a permanent increase in the frequency of microbial biofilm in the central venous catheter, mechanical heart valve, and urinary catheter, as well as persistent infections. However, antimicrobial resistance induced by biofilms formation and the antimicrobial treatment of biofilms were problematic. Moreover, several assays and lab devices were described to evaluate biofilm formation. Furthermore, new attitudes towards anti-biofilm treatments were introduced in this paper. Conclusions: The number of different mechanisms were in accordance with the recent knowledge on how biofilms play a critical role in the disease pathogenesis. Biofilm strikes the treatment and surveillance of patients bearing infectious diseases under different conditions. The use of new methods in anti-biofilm treatments is effective for the recovery of infected patients.

Zinc Deprivation as a Promising Approach for Combating Methicillin-Resistant Staphylococcus aureus: A Pilot Study

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a global health burden with an urgent need for antimicrobial agents. Studies have shown that host immune responses limit essential metals such as zinc during infection, leading to the limitation of bacterial virulence. Thus, the deprivation of zinc as an important co-factor for the activity of many S. aureus enzymes can be a potential antimicrobial approach. However, the effect of zinc deprivation on S. aureus and MRSA is not fully understood. Therefore, the current study aimed to dissect the effects of zinc deprivation on S. aureus hemolytic activity and biofilm formation through employing biochemical and genetic approaches to study the effect of zinc deprivation on S. aureus growth and virulence. Chemically defined media (CDM) with and without ZnCl2, was used to assess the effect of zinc deprivation on growth, biofilm formation, and hemolytic activity in methicillin-susceptible S. aureus (MSSA) RN6390 and MRSA N315 strains. Zinc deprivation decreased the growth of RN6390 and N315 S. aureus strains significantly by 1.5-2 folds, respectively compared to the zinc physiological range encountered by the bacteria in the human body (7-20 µM) (p < 0.05). Zinc deprivation significantly reduced biofilm formation by 1.5 folds compared to physiological levels (p < 0.05). Moreover, the hemolytic activity of RN6390 and N315 S. aureus strains was significantly decreased by 20 and 30 percent, respectively compared to physiological zinc levels (p < 0.05). Expression of biofilm-associated transcripts levels at late stage of biofilm formation (20 h) murein hydrolase activator A (cidA) and cidB were downregulated by 3 and 5 folds, respectively (p < 0.05) suggested an effect on extracellular DNA production. Expression of hemolysins-associated genes (hld, hlb, hla) was downregulated by 3, 5, and 10 folds, respectively, in absence of zinc (p < 0.001). Collectively the current study showed that zinc deprivation in vitro affected growth, biofilm formation, and hemolytic activity of S. aureus. Our in vitro findings suggested that zinc deprivation can be a potential supportive anti-biofilm formation and antihemolytic approach to contain MRSA topical infections.

Enteroaggregative Escherichia coli is associated with antibiotic resistance and urinary tract infection symptomatology

Background

Uropathogenic Escherichia coli (UPEC) is the causative agent of uncomplicated urinary tract infections (UTIs) in ambulatory patients. However, enteroaggregative E. coli (EAEC), an emergent bacterial pathogen that causes persistent diarrhoea, has recently been associated with UTIs. The aim of this study was to determine the frequency of EAEC virulence genes, antibiotic resistance, as well as biofilm production of UPEC isolates obtained from ambulatory patients with non-complicated UTIs that attended to the ISSSTE clinic in Chilpancingo, Guerrero, Mexico, and correlate these with the patients' urinary tract infection symptomatology.

Methods

One hundred clinical isolates were obtained. The identification of clinical isolates, antimicrobial susceptibility testing, and extended spectrum beta-lactamases (ESBLs) production were performed using the Vitek automated system. Assignment of E. coli phylogenetic groups was performed using the quadruplex phylo-group assignment PCR assay. UPEC virulence genes (hlyA, fimH, papC, iutA, and cnf1) and EAEC virulence genes (aap, aggR, and aatA) were detected by multiple PCR.

Results

We found that 22% of the isolates carried the aggR gene and were classified as UPEC/EAEC. The main phylogenetic group was B2 (44.1% were UPEC and 77.27% UPEC/EAEC isolates, respectively). Over half of the UPEC/EAEC isolates (63.64%) were obtained from symptomatic patients, however the aatA gene was the only one found to be associated with the risk of developing pyelonephritis (OR = 5.15, p = 0.038). A total of 77.71% of the UPEC/EAEC isolates were ESBL producers and 90.91% multidrug-resistant (MDR). In conclusion, UPEC/EAEC isolates are more frequent in symptomatic patients and the aatA gene was associated with a higher risk of developing pyelonephritis, along with UPEC genes hlyA and cfn1. UPEC/EAEC isolates obtained from UTI showed ESBL production and MDR.

Prevalence and Impact of Biofilms on Bloodstream and Urinary Tract Infections: A Systematic Review and Meta-Analysis

This study sought to assess the prevalence and impact of biofilms on two commonly biofilm-related infections, bloodstream and urinary tract infections (BSI and UTI). Separated systematic reviews and meta-analyses of observational studies were carried out in PubMed and Web of Sciences databases from January 2005 to May 2020, following PRISMA protocols. Studies were selected according to specific and defined inclusion/exclusion criteria. The obtained outcomes were grouped into biofilm production (BFP) prevalence, BFP in resistant vs. susceptible strains, persistent vs. non-persistent BSI, survivor vs. non-survivor patients with BSI, and catheter-associated UTI (CAUTI) vs. non-CAUTI. Single-arm and two-arm analyses were conducted for data analysis. In vitro BFP in BSI was highly related to resistant strains (odds ratio-OR: 2.68; 95% confidence intervals-CI: 1.60–4.47; p < 0.01), especially for methicillin-resistant Staphylococci. BFP was also highly linked to BSI persistence (OR: 2.65; 95% CI: 1.28–5.48; p < 0.01) and even to mortality (OR: 2.05; 95% CI: 1.53–2.74; p < 0.01). Candida spp. was the microorganism group where the highest associations were observed. Biofilms seem to impact Candida BSI independently from clinical differences, including treatment interventions. Regarding UTI, multi-drug resistant and extended-spectrum β-lactamase-producing strains of Escherichia coli, were linked to a great BFP prevalence (OR: 2.92; 95% CI: 1.30–6.54; p < 0.01 and OR: 2.80; 95% CI: 1.33–5.86; p < 0.01). More in vitro BFP was shown in CAUTI compared to non-CAUTI, but with less statistical confidence (OR: 2.61; 95% CI: 0.67–10.17; p < 0.17). This study highlights that biofilms must be recognized as a BSI and UTI resistance factor as well as a BSI virulence factor.

Temperate Bacteriophages-The Powerful Indirect Modulators of Eukaryotic Cells and Immune Functions

Bacteriophages are natural biological entities that limit the growth and amplification of bacteria. They are important stimulators of evolutionary variability in bacteria, and currently are considered a weapon against antibiotic resistance of bacteria. Nevertheless, apart from their antibacterial activity, phages may act as modulators of mammalian immune responses. In this paper, we focus on temperate phages able to execute the lysogenic development, which may shape animal or human immune response by influencing various processes, including phagocytosis of bacterial invaders and immune modulation of mammalian host cells.

Biofilm inhibition and antifouling evaluation of sol-gel coated silicone implants with prolonged release of eugenol against Pseudomonas aeruginosa

The incidence of biofilm-linked catheter-associated urinary tract infections (CAUTIs) is increasing across the world. However, there is no clinical evidence to support the modifications of biomaterials, such as antimicrobial agent-coated catheters, that are known to reduce the risk of bacterial colonization and resistance development. The present study developed and tested silicone segments coated with an antivirulence agent, eugenol. The parameters for sol-gel preparation and coating were tailored to achieve a prolonged release of eugenol (for >35 days) at predefined antivirulence doses from dip-coated thin films. The eugenol-coated segments could prevent biofilm formation by Pseudomonas aeruginosa PAO1 as well as bacterial adhesion. Significant repression in the expression of virulence and biofilm-associated genes were recorded, confirming the antivirulence and biofilm inhibition properties of silicone segments coated with eugenol. The drug release profiles, efficacy analysis, neutrophil-response studies, and in vitro toxicity profiling further supported the contention that the activity of the eugenol-coated sections was effective and safe.

Correlation Between Biofilm-Formation and the Antibiotic Resistant Phenotype in Staphylococcus aureus Isolates: A Laboratory-Based Study in Hungary and a Review of the Literature

INTRODUCTION

Staphylococcus aureus (S. aureus) is an important causative pathogen in human infections. The production of biofilms by bacteria is an important factor, leading to treatment failures. There has been significant interest in assessing the possible relationship between the multidrug-resistant (MDR) status and the biofilm-producer phenotype in bacteria. The aim of our present study was to assess the biofilm-production rates in clinical methicillin-susceptible S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA] isolates from Hungarian hospitals and the correlation between resistance characteristics and their biofilm-forming capacity.

METHODS

A total of three hundred (n=300) S. aureus isolates (corresponding to MSSA and MRSA isolates in equal measure) were included in this study. Identification of the isolates was carried out using the VITEK 2 ID/AST system and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and E-tests, confirmation of MRSA status was carried out using PBP2a agglutination assay. Biofilm-production was assessed using the crystal violet (CV) tube-adherence method and the Congo red agar (CRA) plate method.

RESULTS

There were significant differences among MSSA and MRSA isolates regarding susceptibility-levels to commonly used antibiotics (in case of erythromycin, clindamycin and ciprofloxacin: p<0.001, gentamicin: p=0.023, sulfamethoxazole/trimethoprim: p=0.027, rifampin: p=0.037). In the CV tube adherence-assay, 37% (n=56) of MSSA and 39% (n=58) of MRSA isolates were positive for biofilm-production, while during the use of CRA plates, 41% (n=61) of MSSA and 44% (n=66) of MRSA were positive; no associations were found between methicillin-resistance and biofilm-production. On the other hand, erythromycin, clindamycin and rifampin resistance was associated with biofilm-positivity (p=0.004, p<0.001 and p<0.001, respectively). Biofilm-positive isolates were most common from catheter-associated infections.

DISCUSSION

Our study emphasizes the need for additional experiments to assess the role biofilms have in the pathogenesis of implant-associated and chronic S. aureus infections.

Evaluation of Antimicrobial and Antioxidant Potential of Essential Oil from Croton piauhiensis Müll. Arg

A large number of infections are caused by Gram-positive and Gram-negative multi-resistant bacteria worldwide, adding up to a figure of around 700,000 deaths per year. The indiscriminate uses of antibiotics, as well as their misuse, resulted in the selection of bacteria resistant to known antibiotics, for which it has little or no treatment. In this way, the strategies to combat the resistance of microorganisms are extremely important and, essential oils of Croton species have been extensively studied for this purpose. The aim of this study was to carry the evaluation of antibacterial, antibiofilm, antioxidant activities, and spectroscopic investigation of essential oil from Croton piauhiensis (EOCp). The EOCp exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria with required MICs ranging from 0.15 to 5% (v/v). In addition, the MBC of the EOCp for Staphylococcus aureus ATCC 25923 and ATCC 700698, were 0.15 and 1.25%, respectively. Moreover, the EOCp significantly reduced significantly the biofilm production and the number of viable cells from the biofilm of all bacterial strains tested. The antioxidant potential of the EOCp showed EC₅₀ values ranging from 171.21 to 4623.83 μg/mL. The EOCp caused hemolysis (>45%) at the higher concentrations tested (1.25 to 5%), and minor hemolysis (17.6%) at a concentration of 0.07%. In addition, docking studies indicated D-limonene as a phytochemical with potential for antimicrobial activity. This study indicated that the EOCp may be a potential agent against infections caused by bacterial biofilms, and act as a protective agent against ROS and oxidative stress.

Santos AC, Cayô R, Gales AC, A. T. Gomes T. Frequency and Diversity of Hybrid Escherichia coli Strains Isolated from Urinary Tract Infections

(1) Background: Hybrid uropathogenic Escherichia coli (UPEC) strains carry virulence markers of the diarrheagenic E. coli (DEC) pathotypes, which may increase their virulence potential. This study analyzed the frequency and virulence potential of hybrid strains among 452 UPEC strains. (2) Methods: Strains were tested for the DEC virulence diagnostic genes’ presence by polymerase chain reaction (PCR). Those carrying at least one gene were classified as hybrid and further tested for 10 UPEC and extraintestinal pathogenic E. coli (ExPEC) virulence genes and phylogenetic classification. Also, their ability to produce hemolysis, adhere to HeLa and renal HEK 293T cells, form a biofilm, and antimicrobial susceptibility were evaluated. (3) Results: Nine (2%) hybrid strains were detected; seven of them carried aggR and two, eae, and were classified as UPEC/EAEC (enteroaggregative E. coli) and UPEC/aEPEC (atypical enteropathogenic E. coli), respectively. They belonged to phylogroups A (five strains), B1 (three), and D (one), and adhered to both cell lineages tested. Only the UPEC/EAEC strains were hemolytic (five strains) and produced biofilm. One UPEC/aEPEC strain was resistant to third-generation cephalosporins and carried bla_CTX-M-15. (4) Conclusions: Our findings contribute to understanding the occurrence and pathogenicity of hybrid UPEC strains, which may cause more severe infections.

Correlation Between Biofilm-Formation and the Antibiotic Resistant Phenotype in Staphylococcus aureus Isolates: A Laboratory-Based Study in Hungary and a Review of the Literature

Introduction

Staphylococcus aureus (S. aureus) is an important causative pathogen in human infections. The production of biofilms by bacteria is an important factor, leading to treatment failures. There has been significant interest in assessing the possible relationship between the multidrug-resistant (MDR) status and the biofilm-producer phenotype in bacteria. The aim of our present study was to assess the biofilm-production rates in clinical methicillin-susceptible S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA] isolates from Hungarian hospitals and the correlation between resistance characteristics and their biofilm-forming capacity.

Methods

A total of three hundred (n=300) S. aureus isolates (corresponding to MSSA and MRSA isolates in equal measure) were included in this study. Identification of the isolates was carried out using the VITEK 2 ID/AST system and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and E-tests, confirmation of MRSA status was carried out using PBP2a agglutination assay. Biofilm-production was assessed using the crystal violet (CV) tube-adherence method and the Congo red agar (CRA) plate method.

Results

There were significant differences among MSSA and MRSA isolates regarding susceptibility-levels to commonly used antibiotics (in case of erythromycin, clindamycin and ciprofloxacin: p<0.001, gentamicin: p=0.023, sulfamethoxazole/trimethoprim: p=0.027, rifampin: p=0.037). In the CV tube adherence-assay, 37% (n=56) of MSSA and 39% (n=58) of MRSA isolates were positive for biofilm-production, while during the use of CRA plates, 41% (n=61) of MSSA and 44% (n=66) of MRSA were positive; no associations were found between methicillin-resistance and biofilm-production. On the other hand, erythromycin, clindamycin and rifampin resistance was associated with biofilm-positivity (p=0.004, p<0.001 and p<0.001, respectively). Biofilm-positive isolates were most common from catheter-associated infections.

Discussion

Our study emphasizes the need for additional experiments to assess the role biofilms have in the pathogenesis of implant-associated and chronic S. aureus infections.

The Role of Antibiotic Resistant A. baumannii in the Pathogenesis of Urinary Tract Infection and the Potential of Its Treatment with the Use of Bacteriophage Therapy

Acinetobacter baumannii are bacteria that belong to the critical priority group due to their carbapenems and third generation cephalosporins resistance, which are last-chance antibiotics. The growing multi-drug resistance and the ability of these bacteria to form biofilms makes it difficult to treat infections caused by this species, which often affects people with immunodeficiency or intensive care unit patients. In addition, most of the infections are associated with catheterization of patients. These bacteria are causative agents, inter alia, of urinary tract infections (UTI) which can cause serious medical and social problems, because of treatment difficulties as well as the possibility of recurrence and thus severely decrease patients' quality of life. Therefore, a promising alternative to standard antibiotic therapy can be bacteriophage therapy, which will generate lower costs and will be safer for the treated patients and has real potential to be much more effective. The aim of the review is to outline the important role of drug-resistant A. baumannii in the pathogenesis of UTI and highlight the potential for fighting these infections with bacteriophage therapy. Further studies on the use of bacteriophages in the treatment of UTIs in animal models may lead to the use of bacteriophage therapy in human urinary tract infections caused by A. baumannii in the future.

Biofilm-Producing Bacteria and Risk Factors (Gender and Duration of Catheterization) Characterized as Catheter-Associated Biofilm Formation

Background

A catheter-associated urinary tract infection (CA-UTI) is preceded by biofilm formation, which is related to several risk factors such as gender, age, diabetic status, duration of catheterization, bacteriuria before catheterization, virulence gene factor, and antibiotic usage.

Aims

This study aims to identify the microbial composition of catheter samples, including its corresponding comparison with urine samples, to determine the most important risk factors of biofilm formation and characterize the virulence gene factors that correlate with biofilm formation.

Methods

A longitudinal cross-sectional study was conducted on 109 catheterized patients from September 2017 to January 2018. The risk factors were obtained from the patients' medical records. All catheter and urine samples were cultured after removal, followed by biomass quantification. Isolate identification and antimicrobial susceptibility testing were performed using the Vitex2 system. Biofilm-producing bacteria were identified by the Congo Red Agar (CRA) method. A PCR test characterized the virulence genes of dominant bacteria (E. coli). All data were collected and processed for statistical analysis.

Results

Out of 109 catheterized patients, 78% of the catheters were culture positive, which was higher than those of the urine samples (37.62%). The most common species isolated from the catheter cultures were Escherichia coli (28.1%), Candida sp. (17.8%), Klebsiella pneumoniae (15.9%), and Enterococcus faecalis (13.1%). E. coli (83.3%) and E. faecalis (78.6%) were the main isolates with a positive CRA. A statistical analysis showed that gender and duration prior to catheterization were associated with an increased risk of biofilm formation (p < 0.05).

Conclusion

E. coli and E. faecalis were the most common biofilm-producing bacteria isolated from the urinary catheter. Gender and duration are two risk factors associated with biofilm formation, therefore determining the risk of CAUTI. The presence of PapC as a virulence gene encoding pili correlates with the biofilm formation. Biofilm-producing bacteria, female gender, duration of catheterization (more than five days), and PapC gene presence have strong correlation with the biofilm formation. To prevent CAUTI, patients with risk factors should be monitored by urinalysis tests to detect earlier the risk of biofilm formation.

Molecular, phylogenetic and antibiotic resistance analysis of enteroaggregative escherichia coli/uropathogenic Escherichia coli hybrid genotypes causing urinary tract infections

Background

Horizontal gene transfer of virulence genes (VGs) from different Escherichia coli pathotypes results in the evolution of hybrid strains. Hybrid genotypes of enteroaggregative E. coli and uropathogenic E. coli (EAEC/UPEC) have been reported in sporadic infections and outbreaks of extraintestinal origin. Yet, their association with routine infections is still underrated.

Materials and Methods

In this study, we analysed 163 isolates of E. coli from cases of urinary tract infection seeking hybrid (EAEC/UPEC) strains. Using multiplex polymerase chain reaction, we investigated VGs (adhesive and toxin genes) of UPEC along with EAEC marker genes (aap and agg R), ast A (toxin genes) and serine protease autotransporters of Enterobacteriaceae, pet (plasmid-encoded toxin) and pic (mucinase gene). Those UPEC strains which had characteristic defining genes of EAEC (agg R/aap or their combination) were considered UPEC/EAEC hybrids.

Results

Molecular predictors of EAEC (aap and aggR) were detected in 20.2% (33/163) of the strains. The pap C was also detected in 36% of the EAEC/UPEC hybrid strains. Phylogenetic analysis revealed that hybrid strains belonged to Group D (60.6%). Nearly 73.8% of UPEC and 75.7% of UPEC/EAEC hybrid strains were multidrug-resistant. Among UPEC isolates, 72.3% and in hybrid UPEC/EAEC, 78.7% isolates were able to produce biofilm.

Conclusions

Our results indicated a closer relationship among EAEC and UPEC, which suggested that some EAEC strains can be potential uropathogens. Ours is a first study documenting the existence of EAEC pathotypes VGs in UPEC strains of nosocomial origin; further studies are required to understand the diarrhoeagenic potential of these hybrids.

Relationship between Virulence and Resistance among Gram-Negative Bacteria

Bacteria present in the human body are innocuous, providing beneficial functions, some of which are necessary for correct body function. However, other bacteria are able to colonize, invade, and cause damage to different tissues, and these are categorised as pathogens. These pathogenic bacteria possess several factors that enable them to be more virulent and cause infection. Bacteria have a great capacity to adapt to different niches and environmental conditions (presence of antibiotics, iron depletion, etc.). Antibiotic pressure has favoured the emergence and spread of antibiotic-resistant bacteria worldwide. Several studies have reported the presence of a relationship (both positive and negative, and both direct and indirect) between antimicrobial resistance and virulence among bacterial pathogens. This review studies the relationship among the most important Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) taking into account two points of view: (i) the effect the acquisition of resistance has on virulence, and (ii) co-selection of resistance and virulence. The relationship between resistance and virulence among bacteria depends on the bacterial species, the specific mechanisms of resistance and virulence, the ecological niche, and the host.

Increasing relevance of Gram-positive cocci in urinary tract infections: a 10-year analysis of their prevalence and resistance trends

Urinary tract infections (UTIs) are the third most common types of infection in human medicine worldwide. There is increasing appreciation for the pathogenic role of Gram-positive cocci (GPC) in UTIs, as they have a plethora of virulence factors, maintaining their pathogenicity and high affinity for the epithelial cells of the urinary tract. The study was carried out using microbiological data collected corresponding to the period between 2008 and 2017. Antimicrobial susceptibility testing was performed using the disk diffusion method and E-tests. The age range of patients affected from the outpatient and inpatient groups differed significantly (43 [range 0.7-99] vs. 68 [range 0.4-99] years; p = 0.008). 3962 GPCs were obtained from inpatient and 4358 from outpatient samples, corresponding to 20.5 ± 2.8% (range 17.5-26.8%) and 20.6 ± 2.6% (range 17.8-26.0%) of all positive urine samples (p > 0.05); in both groups, Enterococcus spp. were the most prevalent (outpatients: 79.6%; inpatients: 88.5%). High-level aminoglycoside resistance in enterococci was noted in 31.0-46.6% of cases. A pronounced increase in the number of MRSA was seen in the second half of the study period (0.6-1.9% vs. 9.8-11.6%; p = 0.038). The ratio of VRE isolates was 0.16%, no VISA/VRSA isolates were detected.

Increasing relevance of Gram-positive cocci in urinary tract infections: a 10-year analysis of their prevalence and resistance trends

Urinary tract infections (UTIs) are the third most common types of infection in human medicine worldwide. There is increasing appreciation for the pathogenic role of Gram-positive cocci (GPC) in UTIs, as they have a plethora of virulence factors, maintaining their pathogenicity and high affinity for the epithelial cells of the urinary tract. The study was carried out using microbiological data collected corresponding to the period between 2008 and 2017. Antimicrobial susceptibility testing was performed using the disk diffusion method and E-tests. The age range of patients affected from the outpatient and inpatient groups differed significantly (43 [range 0.7–99] vs. 68 [range 0.4–99] years; p = 0.008). 3962 GPCs were obtained from inpatient and 4358 from outpatient samples, corresponding to 20.5 ± 2.8% (range 17.5–26.8%) and 20.6 ± 2.6% (range 17.8–26.0%) of all positive urine samples (p > 0.05); in both groups, Enterococcus spp. were the most prevalent (outpatients: 79.6%; inpatients: 88.5%). High-level aminoglycoside resistance in enterococci was noted in 31.0–46.6% of cases. A pronounced increase in the number of MRSA was seen in the second half of the study period (0.6–1.9% vs. 9.8–11.6%; p = 0.038). The ratio of VRE isolates was 0.16%, no VISA/VRSA isolates were detected.

Efficacy of an orally administered combination of Lactobacillus paracasei LC11, cranberry and D-mannose for the prevention of uncomplicated, recurrent urinary tract infections in women

BACKGROUND

Most women experience a urinary tract infection (UTI) at least once in their lifetime. The present study determined the efficacy and safety of a combination of Lactobacillus paracasei LC11, cranberry and D-mannose (Lactoflorene Cist^®) in the prophylaxis of recurrent uncomplicated UTIs in premenopausal women.

METHODS

This single-centre study enrolled premenopausal women aged 18-50 years with an acute UTI and a history of recurrent uncomplicated UTIs. Patients were first treated with fosfomycin (3 g once a day for 2 days) to eliminate any underlying infection, followed by treatment with Lactoflorene Cist^® once a day for 10 days/month for 90 days (Group 1), Lactoflorene Cist^® once daily for 90 days (Group 2) or no treatment (Group 3; control). The main study endpoint was the rate of UTI recurrence during the study period. Any adverse events with treatment were also recorded.

RESULTS

A total of 55 women (mean age 39.3 years; range: 20-46) were enrolled in the study. A significantly higher proportion of patients in the control group experienced UTIs during the study period compared with the two treatment groups (52.9% vs 16.0% in Group 1 and 15.5% in group 2; p < 0.01). Similarly, a higher proportion of patients in Group 1 (65.8%) and Group 2 (68.7%) remained UTI-free during the study versus the control group. No adverse events were reported in the treated patients.

CONCLUSION

Prophylactic treatment with Lactoflorene Cist^® was effective and safe in the management of recurrent uncomplicated UTIs in premenopausal women.