Biofilms are communities of microorganisms that are formed on and attached to living or nonliving surfaces and are surrounded by an extracellular polymeric material. Biofilm formation enjoys several ...advantages over the pathogens in the colonization process of medical devices and patients' organs. Unlike planktonic cells, biofilms have high intrinsic resistance to antibiotics and sanitizers, and overcoming them is a significant problematic challenge in the medical and food industries. There are no approved treatments to specifically target biofilms. Thus, it is required to study and present innovative and effective methods to combat a bacterial biofilm. In this review, several strategies have been discussed for combating bacterial biofilms to improve healthcare, food safety, and industrial process.
Bacteria are the cause of evolution of several strategies to deal with problems and challenges existing under hostile environments. One of the significant survival strategies used by bacteria is a biofilm formation. we have tried to provide a comprehensive picture of current knowledge about antibiofilm agents of different sources.
Vancomycin-resistant Staphylococcus aureus (VRSA), Vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA) are subject to vancomycin treatment failure. The aim of the present study ...was to determine their precise prevalence and investigate prevalence variability depending on different years and locations. Several international databases including Medline (PubMed), Embase and Web of Sciences were searched (data from 1997 to 2019) to identify studies that addressed the prevalence of VRSA, VISA and hVISA among human clinical isolates around the world. Subgroup analyses and meta-regression were conducted to indicate potential source of variation. Publication bias was assessed using Egger's test. Statistical analyses were conducted using STATA software (version 14.0). Data analysis showed that VRSA, VISA and hVISA isolates were reported in 23, 50 and 82 studies, with an overall prevalence of 1.5% among 5855 S. aureus isolates, 1.7% among 22,277 strains and 4.6% among 47,721 strains, respectively. The overall prevalence of VRSA, VISA, and hVISA before 2010 was 1.2%, 1.2%, and 4%, respectively, while their prevalence after this year has reached 2.4%, 4.3%, and 5.3%. The results of this study showed that the frequency of VRSA, VISA and hVISA after 2010 represent a 2.0, 3.6 and 1.3-fold increase over prior years. In a subgroup analysis of different strain origins, the highest frequency of VRSA (3.6%) and hVISA (5.2%) was encountered in the USA while VISA (2.1%) was more prevalent in Asia. Meta-regression analysis showed significant increasing of VISA prevalence in recent years (p value ≤ 0.05). Based on the results of case reports (which were not included in the calculations mentioned above), the numbers of VRSA, VISA and hVISA isolates were 12, 24 and 14, respectively, among different continents. Since the prevalence of VRSA, VISA and hVISA has been increasing in recent years (especially in the Asian and American continents), rigorous monitoring of vancomycin treatment, it's the therapeutic response and the definition of appropriate control guidelines depending on geographical regions is highly recommended and essential to prevent the further spread of vancomycin-resistant S. aureus.
We analyzed the potential antibacterial effects of two different PdB against methicillin-resistant S. aureus and P. aeruginosa. The third-degree burn wound healing effects of PdB was also studied. ...Blood samples were obtained from 10 healthy volunteers and biological assays of the PdB were performed and the antimicrobial activity against MRSA and P. aeruginosa was determined using disk diffusion (DD), broth microdilution (BMD), and time-kill assay methods. 48 Wistar albino rats were burned and infected with MRSA. Two groups were injected PdB, the control groups were treated with plasma and received no treatment respectively. In the next step, the rats were euthanized and skin biopsies were collected and histopathologic changes were examined. The results of DD and BMD showed that both PdB performed very well on MRSA, whereas P. aeruginosa was only inhibited by F-PdB and was less susceptible than MRSA to PdBs. The time-kill assay also showed that F-PdB has an antibacterial effect at 4 hours for two strains. Histopathological studies showed that the treated groups had less inflammatory cells and necrotic tissues. Our data suggest that PdB may possess a clinical utility as a novel topical antimicrobial and wound healing agent for infected burn wounds.
Bacterial infection of the wound could potentially cause serious complications and an enormous medical and financial cost to the rapid emergence of drug-resistant bacteria. Nanomaterials are an ...emerging technology, that has been researched as possible antimicrobial nanomaterials for the inhibition of wound infection and enhancement of wound healing. Graphene is 2-dimensional (2D) sheet of sp2 carbon atoms in a honeycomb structure. It has superior properties, strength, conductivity, antimicrobial, and molecular carrier abilities. Graphene and its derivatives, Graphene oxide (GO) and reduced GO (rGO), have antibacterial activity and could damage bacterial morphology and lead to the leakage of intracellular substances. Besides, for wound infection management, Graphene-platforms could be functionalized by different antibacterial agents such as metal-nanoparticles, natural compounds, and antibiotics. The Graphene structure can absorb near-infrared wavelengths, allowing it to be used as antimicrobial photodynamic therapy. Therefore, Graphene-based material could be used to inhibit pathogens that cause serious skin infections and destroy their biofilm community, which is one of the biggest challenges in treating wound infection. Due to its agglomerated structure, GO hydrogel could entrap and stack the bacteria; thus, it prevents their initial attachment and biofilm formation. The sharp edges of GO could destroy the extracellular polymeric substance surrounding the biofilm and ruin the biofilm biomass structure. As well as, Chitosan and different natural and synthetic polymers such as collagen and polyvinyl alcohol (PVA) also have attracted a great deal of attention for use with GO as wound dressing material. To this end, multi-functional polymers based on Graphene and blends of synthetic and natural polymers can be considered valid non-antibiotic compounds useful against wound infection and improvement of wound healing. Finally, the global wound care market size was valued at USD 20.8 billion in 2022 and is expected to expand at a compound annual growth rate (CAGR) of 5.4% from 2022 to 2027 (USD 27.2 billion). This will encourage academic as well as pharmaceutical and medical device industries to investigate any new materials such as graphene and its derivatives for the treatment of wound healing.
Multi-Drug Resistant (MDR) uropathogenic bacteria have increased in number in recent years and the development of new treatment options for the corresponding infections has become a major challenge ...in the field of medicine. In this respect, recent studies have proposed bacteriophage (phage) therapy as a potential alternative against MDR Urinary Tract Infections (UTI) because the resistance mechanism of phages differs from that of antibiotics and few side effects have been reported for them. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis are the most common uropathogenic bacteria against which phage therapy has been used. Phages, in addition to lysing bacterial pathogens, can prevent the formation of biofilms. Besides, by inducing or producing polysaccharide depolymerase, phages can easily penetrate into deeper layers of the biofilm and degrade it. Notably, phage therapy has shown good results in inhibiting multiple-species biofilm and this may be an efficient weapon against catheter-associated UTI. However, the narrow range of hosts limits the use of phage therapy. Therefore, the use of phage cocktail and combination therapy can form a highly attractive strategy. However, despite the positive use of these treatments, various studies have reported phage-resistant strains, indicating that phage-host interactions are more complicated and need further research. Furthermore, these investigations are limited and further clinical trials are required to make this treatment widely available for human use. This review highlights phage therapy in the context of treating UTIs and the specific considerations for this application.
The high occurrence and mortality rates related to candidiasis emphasize the urgent need to introduce new therapeutic approaches to treat this infection. Eugenol, the main phenolic component of
Clove
...and
Cinnamomum
essential oil, has been used to inhibit growth and different virulence factors of
Candida
, including strains with decreased susceptibility to antifungals, particularly fluconazole. The results showed that this compound could bind to
Candida
membrane and decrease ergosterol biosynthesis, consequently leading to cell wall and membrane damage. Additionally, eugenol not only reduced germ tube formation, which reduces nutrient absorption from host tissues, but it also increased the levels of lipid peroxidation and reactive oxygen species, which induces oxidative stress and causes high permeability in the fungal cell membrane. Eugenol inhibited
Candida
cells’ adhesion capacity; additionally, this compound inhibited the formation of biofilms and eliminated established
Candida
biofilms on a variety of surfaces. Furthermore, by disrupting fungal cell integrity, eugenol could boost the entry of the antifungal drugs into the
Candida
cell, improving treatment efficacy. Therefore, eugenol could be used in the clinical management of various presentations of candidiasis, especially mucocutaneous presentations such as oral and vulvovaginal infections. However, further investigations, including
in vivo
and animal studies, toxicology studies and clinical trials, as well as molecular analysis, are needed to improve formulations and develop novel antifungal agents based on eugenol.
Multi-Drug Resistant (MDR) Pseudomonas aeruginosa is one of the most important bacterial pathogens that causes infection with a high mortality rate due to resistance to different antibiotics. This ...bacterium prompts extensive tissue damage with varying factors of virulence, and its biofilm production causes chronic and antibiotic-resistant infections. Therefore, due to the non-applicability of antibiotics for the destruction of P. aeruginosa biofilm, alternative approaches have been considered by researchers, and phage therapy is one of these new therapeutic solutions. Bacteriophages can be used to eradicate P. aeruginosa biofilm by destroying the extracellular matrix, increasing the permeability of antibiotics into the inner layer of biofilm, and inhibiting its formation by stopping the quorum-sensing activity. Furthermore, the combined use of bacteriophages and other compounds with anti-biofilm properties such as nanoparticles, enzymes, and natural products can be of more interest because they invade the biofilm by various mechanisms and can be more effective than the one used alone. On the other hand, the use of bacteriophages for biofilm destruction has some limitations such as limited host range, high-density biofilm, sub-populate phage resistance in biofilm, and inhibition of phage infection via quorum sensing in biofilm. Therefore, in this review, we specifically discuss the use of phage therapy for inhibition of P. aeruginosa biofilm in clinical and in vitro studies to identify different aspects of this treatment for broader use.
Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MRCoNS) are among the main causes of nosocomial infections, which have caused major ...problems in recent years due to continuously increasing spread of various antibiotic resistance features. Apparently, vancomycin is still an effective antibiotic for treatment of infections caused by these bacteria but in recent years, additional resistance phenotypes have led to the accelerated introduction of newer agents such as linezolid, tigecycline, daptomycin, and quinupristin/dalfopristin (Q/D). Due to limited data availability on the global rate of resistance to these antibiotics, in the present study, the resistance rates of S. aureus, Methicillin-resistant S. aureus (MRSA), and CoNS to these antibiotics were collected.
Several databases including web of science, EMBASE, and Medline (via PubMed), were searched (September 2018) to identify those studies that address MRSA, and CONS resistance to linezolid, tigecycline, daptomycin, and Q/D around the world.
Most studies that reported resistant staphylococci were from the United States, Canada, and the European continent, while African and Asian countries reported the least resistance to these antibiotics. Our results showed that linezolid had the best inhibitory effect on S. aureus. Although resistances to this antibiotic have been reported from different countries, however, due to the high volume of the samples and the low number of resistance, in terms of statistical analyzes, the resistance to this antibiotic is zero. Moreover, linezolid, daptomycin and tigecycline effectively (99.9%) inhibit MRSA. Studies have shown that CoNS with 0.3% show the lowest resistance to linezolid and daptomycin, while analyzes introduced tigecycline with 1.6% resistance as the least effective antibiotic for these bacteria. Finally, MRSA and CoNS had a greater resistance to Q/D with 0.7 and 0.6%, respectively and due to its significant side effects and drug-drug interactions; it appears that its use is subject to limitations.
The present study shows that resistance to new agents is low in staphylococci and these antibiotics can still be used for treatment of staphylococcal infections in the world.
The biofilm communities of
Candida
are resistant to various antifungal treatments. The ability of
Candida
to form biofilms on abiotic and biotic surfaces is considered one of the most important ...virulence factors of these fungi. Extracellular DNA and exopolysaccharides can lower the antifungal penetration to the deeper layers of the biofilms, which is a serious concern supported by the emergence of azole-resistant isolates and
Candida
strains with decreased antifungal susceptibility. Since the biofilms’ resistance to common antifungal drugs has become more widespread in recent years, more investigations should be performed to develop novel, inexpensive, non-toxic, and effective treatment approaches for controlling biofilm-associated infections. Scientists have used various natural compounds for inhibiting and degrading
Candida
biofilms. Curcumin, cinnamaldehyde, eugenol, carvacrol, thymol, terpinen-4-ol, linalool, geraniol, cineole, saponin, camphor, borneol, camphene, carnosol, citronellol, coumarin, epigallocatechin gallate, eucalyptol, limonene, menthol, piperine, saponin, α-terpineol, β–pinene, and citral are the major natural compounds that have been used widely for the inhibition and destruction of
Candida
biofilms. These compounds suppress not only fungal adhesion and biofilm formation but also destroy mature biofilm communities of
Candida
. Additionally, these natural compounds interact with various cellular processes of
Candida
, such as ABC-transported mediated drug transport, cell cycle progression, mitochondrial activity, and ergosterol, chitin, and glucan biosynthesis. The use of various drug delivery platforms can enhance the antibiofilm efficacy of natural compounds. Therefore, these drug delivery platforms should be considered as potential candidates for coating catheters and other medical material surfaces. A future goal will be to develop natural compounds as antibiofilm agents that can be used to treat infections by multi-drug-resistant
Candida
biofilms. Since exact interactions of natural compounds and biofilm structures have not been elucidated, further
in vitro
toxicology and animal experiments are required. In this article, we have discussed various aspects of natural compound usage for inhibition and destruction of
Candida
biofilms, along with the methods and procedures that have been used for improving the efficacy of these compounds.
Helicobacter pylori, the most frequent pathogen worldwide that colonizes around 50% of the world's population, causes important diseases such as gastric adenocarcinoma, chronic gastritis, and gastric ...mucosa-associated lymphoid tissue (MALT) lymphoma. In recent years, various studies have reported that H. pylori biofilm may be one of the critical barriers to the eradication of this bacterial infection. Biofilms inhibit the penetration of antibiotics, increase the expression of efflux pumps and mutations, multiple therapeutic failures, and chronic infections. Nanoparticles and natural products can demolish H. pylori biofilm by destroying the outer layers and inhibiting the initial binding of bacteria. Also, the use of combination therapies destroying extracellular polymeric substances decreases coccoid forms of bacteria and degrading polysaccharides in the outer matrix that lead to an increase in the permeability and performance of antibiotics. Different probiotics, antimicrobial peptides, chemical substances, and polysaccharides by inhibiting adhesion and colonization of H. pylori can prevent biofilm formation by this bacterium. Of note, many of the above are applicable to acidic pH and can be used to treat gastritis. Therefore, H. pylori biofilm may be one of the major causes of failure to eradication of infections caused by this bacterium, and antibiotics are not capable of destroying the biofilm. Thus, it is necessary to use new strategies to prevent recurrent and chronic infections by inhibiting biofilm formation.
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