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The Journal of Hospital Infection Feb 2024Bacteria are known to live inside architectural structures called biofilms. Though standard biofilms have been studied extensively for more than 50 years, little is...
BACKGROUND
Bacteria are known to live inside architectural structures called biofilms. Though standard biofilms have been studied extensively for more than 50 years, little is known about dry-surface biofilms (DSBs). Since 2012, DSBs have been described in several scientific papers, but basic knowledge about the viability and culturability of bacteria remains limited.
AIM
To conduct a systematic review to determine whether bacteria inside DSBs are viable, culturable, and enumerable.
METHODS
Eligible articles had to deal with DSBs containing at least one bacterial species involved in healthcare-associated infections, which developed in actual healthcare environments (in-situ) or with the help of any biofilm model (in-vitro).
FINDINGS
Twenty-four articles were included in the review. Whereas most of them isolated viable bacteria (87% in situ; 100% in vitro), no in-situ study quantified culturable bacteria in the biofilm per unit area. Conversely, 100% of in-vitro studies cultured the bacteria from controls and 94.4% supplied an enumeration of them. Culturable bacteria also grew after 78% of the cleaning, disinfection, or sterilization protocols tested. Microscopic observations after staining the samples with live/dead fluorescent probes (Baclight®) showed large amounts of viable cells in culture-negative samples.
CONCLUSION
Our study questions the efficacy of current methods for microbiological monitoring of surfaces, since these methods are only based on bacterial culturability. To improve both surface monitoring and cleaning and disinfection protocols, it is necessary to integrate the concept of DSBs which appears to contain a significant amount of viable but non-culturable bacteria.
Topics: Biofilms; Desiccation; Disinfection; Health Facilities; Microbial Viability
PubMed: 38029859
DOI: 10.1016/j.jhin.2023.11.004 -
Frontiers in Cellular and Infection... 2023The presence of host collagenases in the degradation of the protein matrix at later stages of carious dentin lesions development, as well as the potential involvement of... (Review)
Review
INTRODUCTION AND AIM
The presence of host collagenases in the degradation of the protein matrix at later stages of carious dentin lesions development, as well as the potential involvement of bacterial collagenases, have been suggested but lack conclusive evidence. This study aims to conduct a systematic review to comprehensively assess the profile of host and bacterial-derived collagenolytic proteases in both root and coronal dentin carious lesions.
METHODS
The search was performed in eight databases and the grey literature. Studies evaluating dentin, extracted teeth, or biofilms from natural caries lesions were included. The methodological quality of studies was assessed using the Joanna Briggs Institute tool. Synthesis of the results and the certainty of evidence were performed following the Synthesis without Meta-analysis (SWiM) checklist and GRADE approach for narrative synthesis, respectively.
RESULTS
From 935 recovered articles, 18 were included. Although the evidence was very uncertain, it was possible to suggest that 1) MMP-2, MMP-9, MMP-13, and CT-B may be increased in carious dentin when compared to sound dentin; 2) there is no difference in MMP-2 presence, while MMP-13 may be increased in root when compared to coronal carious dentin; 3) there is no difference of MMP-2 and MMP-9 expression/activity before and after cavity sealing; 4) MMP-8 may be increased in the dentin before cavity sealing compared to dentin after cavity sealing; 5) there is no difference of MMP-20 in irradiated vs. non-irradiated carious dentin. MMP-20 probably reduces in carious outer dentin when compared to carious inner dentin (moderate certainty). Genes encoding bacterial collagenolytic proteases and protein-degrading bacteria were detected in coronal and root carious lesions.
CONCLUSION
Trends in the direction of the effect were observed for some collagenolytic proteases in carious dentin, which may represent a potential target for the development of new treatments. (Protocol register-PROSPERO: CRD42020213141).
Topics: Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Dentin; Matrix Metalloproteinase 13; Peptide Hydrolases; Matrix Metalloproteinase 20; Collagenases; Bacteria; Dental Caries
PubMed: 38029242
DOI: 10.3389/fcimb.2023.1278754 -
Journal of Research in Medical Sciences... 2023Different virulence factors are involved in the pathogenesis of urinary tract infection (UTI) caused by Uropathogenic (UPEC); hence, this study aimed to study the... (Review)
Review
BACKGROUND
Different virulence factors are involved in the pathogenesis of urinary tract infection (UTI) caused by Uropathogenic (UPEC); hence, this study aimed to study the prevalence of biofilm formation, virulence factors, and phylogenetic groups and their correlation with biofilm formation among UPEC isolates through a systematic review and meta-analysis.
MATERIALS AND METHODS
A literature search was conducted from 1, 2000, to the end of 2021 in different databases for studies that reported biofilm together with virulence genes or phylogenetic groups in UPEC isolates from patients with UTI according to PRISMA protocol. Data were analyzed by Comprehensive meta-analysis software.
RESULTS
The pooled prevalence of biofilm formers was 74.7%. The combined prevalence of phylogenetic Groups A, B1, B2, and D (s) were reported at 19.6%, 11%, 50.7%, and 20.5%, respectively. The most common virulence genes reported worldwide were , , and , with a combined prevalence of 90.3%, 86.6%, and 64.9%, respectively. The pooled prevalence of biofilm formation in UPEC isolates with phylogenetic Groups A, B1, B2, D, C, and F were 12.4%, 8.7%, 33.7%, 12.4%, 2.6%, and 2.65%, respectively. Several studies showed a correlation between biofilm production and virulence genes, or phylogenetic groups.
CONCLUSION
Regarding data obtained, the high level of combined biofilm formation (74.7%) and the presence of a positive correlation between biofilm production and virulence genes, or phylogenetic groups as reported by the most studies included in the present review, indicates an important role of biofilm in the persistence of UPEC in the UTI.
PubMed: 38024522
DOI: 10.4103/jrms.jrms_637_22 -
Biomolecules Oct 2023The emergence of dental implants has revolutionized the management of tooth loss. However, the placement of clinical implants exposes them to complex oral environment... (Review)
Review
BACKGROUND
The emergence of dental implants has revolutionized the management of tooth loss. However, the placement of clinical implants exposes them to complex oral environment and numerous microscopic entities, such as bacteria. Cold atmospheric plasma (CAP) is often used to treat the surfaces of dental implants, which alters morphological features and effectively reduces bacterial load.
PURPOSE
This systematic review aims to assess the existing literature on the bactericidal properties of CAP when used on various kinds of dental implant surfaces.
REVIEW METHOD
An in-depth examination of MEDLINE/PubMed and EMBASE was performed to identify relevant studies, with the most recent search conducted in May 2023. Studies were selected based on their exploration of CAP's effects on dental implants compared to control groups, focusing on CAP's bactericidal efficacy. However, studies that lacked a control group or that failed to measure bactericidal effects were excluded.
RESULTS
After applying the selection criteria, 15 studies were ultimately included in the systematic review. The collected data suggest that CAP can effectively reduce bacterial loads on dental implant surfaces, including pathogens like and . Furthermore, CAP appears to combat biofilms and plaques that are key contributors to periimplantitis.
CONCLUSION
CAP emerges as a promising treatment option, exhibiting significant bactericidal activity on dental implant surfaces. CAP can decrease the rates of bacterial biofilm and plaque formation, leading to improved outcomes for dental implant patients.
Topics: Humans; Dental Implants; Plasma Gases; Bacteria; Biofilms; Bacterial Load; Anti-Bacterial Agents
PubMed: 37892210
DOI: 10.3390/biom13101528 -
The Cochrane Database of Systematic... Oct 2023Otitis media with effusion (OME) is an accumulation of fluid in the middle ear cavity, common amongst young children. The fluid may cause hearing loss. When persistent,... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Otitis media with effusion (OME) is an accumulation of fluid in the middle ear cavity, common amongst young children. The fluid may cause hearing loss. When persistent, it may lead to developmental delay, social difficulty and poor quality of life. Management of OME includes watchful waiting, autoinflation, medical and surgical treatment. Antibiotics are sometimes used to treat any bacteria present in the effusion, or associated biofilms.
OBJECTIVES
To assess the effects (benefits and harms) of oral antibiotics for otitis media with effusion (OME) in children.
SEARCH METHODS
The Cochrane ENT Information Specialist searched the Cochrane ENT Register, CENTRAL, Ovid MEDLINE, Ovid Embase, Web of Science, ClinicalTrials.gov, ICTRP and additional sources for published and unpublished studies to 20 January 2023.
SELECTION CRITERIA
We included randomised controlled trials and quasi-randomised trials in children aged 6 months to 12 years with unilateral or bilateral OME. We included studies that compared oral antibiotics with either placebo or no treatment.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methods. Our primary outcomes were determined following a multi-stakeholder prioritisation exercise and were: 1) hearing, 2) otitis media-specific quality of life and 3) anaphylaxis. Secondary outcomes were: 1) persistence of OME, 2) adverse effects, 3) receptive language skills, 4) speech development, 5) cognitive development, 6) psychosocial skills, 7) listening skills, 8) generic health-related quality of life, 9) parental stress, 10) vestibular function and 11) episodes of acute otitis media. We used GRADE to assess the certainty of evidence for each outcome. Although we included all measures of hearing assessment, the proportion of children who returned to normal hearing was our preferred method to assess hearing, due to challenges in interpreting the results of mean hearing thresholds.
MAIN RESULTS
We identified 19 completed studies that met our inclusion criteria (2581 participants). They assessed a variety of oral antibiotics (including penicillins, cephalosporins, macrolides and trimethoprim), with most studies using a 10- to 14-day treatment course. We had some concerns about the risk of bias in all studies included in this review. Here we report our primary outcomes and main secondary outcome, at the longest reported follow-up time. Antibiotics versus placebo We included 11 studies for this comparison, but none reported all of our outcomes of interest and limited meta-analysis was possible. Hearing One study found that more children may return to normal hearing by two months (resolution of the air-bone gap) after receiving antibiotics as compared with placebo, but the evidence is very uncertain (Peto odds ratio (OR) 9.59, 95% confidence interval (CI) 3.51 to 26.18; 20/49 children who received antibiotics returned to normal hearing versus 0/37 who received placebo; 1 study, 86 participants; very low-certainty evidence). Disease-specific quality of life No studies assessed this outcome. Presence/persistence of OME At 6 to 12 months of follow-up, the use of antibiotics compared with placebo may slightly reduce the number of children with persistent OME, but the confidence intervals were wide, and the evidence is very uncertain (risk ratio (RR) 0.89, 95% CI 0.68 to 1.17; 48% versus 54%; number needed to treat (NNT) 17; 2 studies, 324 participants; very low-certainty evidence). Adverse event: anaphylaxis No studies provided specific data on anaphylaxis. Three of the included studies (448 children) did report adverse events in sufficient detail to assume that no anaphylactic reactions occurred, but the evidence is very uncertain (very low-certainty evidence). Antibiotics versus no treatment We included eight studies for this comparison, but very limited meta-analysis was possible. Hearing One study found that the use of antibiotics compared to no treatment may result in little to no difference in final hearing threshold at three months (mean difference (MD) -5.38 dB HL, 95% CI -9.12 to -1.64; 1 study, 73 participants; low-certainty evidence). The only data identified on the return to normal hearing were reported at 10 days of follow-up, which we considered to be too short to accurately reflect the efficacy of antibiotics. Disease-specific quality of life No studies assessed this outcome. Presence/persistence of OME Antibiotics may reduce the proportion of children who have persistent OME at up to three months of follow-up, when compared with no treatment (RR 0.64, 95% CI 0.50 to 0.80; 6 studies, 542 participants; low-certainty evidence). Adverse event: anaphylaxis No studies provided specific data on anaphylaxis. Two of the included studies (180 children) did report adverse events in sufficient detail to assume that no anaphylactic reactions occurred, but the evidence is very uncertain (very low-certainty evidence).
AUTHORS' CONCLUSIONS
The evidence for the use of antibiotics for OME is of low to very low certainty. Although the use of antibiotics compared to no treatment may have a slight beneficial effect on the resolution of OME at up to three months, the overall impact on hearing is very uncertain. The long-term effects of antibiotics are unclear and few of the studies included in this review reported on potential harms. These important endpoints should be considered when weighing up the potential short- and long-term benefits and harms of antibiotic treatment in a condition with a high spontaneous resolution rate.
Topics: Child; Humans; Child, Preschool; Anti-Bacterial Agents; Otitis Media with Effusion; Quality of Life; Anaphylaxis; Hearing Loss
PubMed: 37870130
DOI: 10.1002/14651858.CD015254.pub2 -
Clinical Microbiology and Infection :... Feb 2024Whether trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis prevents nocardiosis in solid organ transplant (SOT) recipients is controversial. (Meta-Analysis)
Meta-Analysis Review
Trimethoprim-sulfamethoxazole significantly reduces the risk of nocardiosis in solid organ transplant recipients: systematic review and individual patient data meta-analysis.
BACKGROUND
Whether trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis prevents nocardiosis in solid organ transplant (SOT) recipients is controversial.
OBJECTIVES
To assess the effect of TMP-SMX in the prevention of nocardiosis after SOT, its dose-response relationship, its effect on preventing disseminated nocardiosis, and the risk of TMP-SMX resistance in case of breakthrough infection.
METHODS
A systematic review and individual patient data meta-analysis.
DATA SOURCES
MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Science Core Collection, and Scopus up to 19 September 2023.
STUDY ELIGIBILITY CRITERIA
(a) Risk of nocardiosis between SOT recipients with and without TMP-SMX prophylaxis, or (b) sufficient details to determine the rate of TMP-SMX resistance in breakthrough nocardiosis.
PARTICIPANTS
SOT recipients.
INTERVENTION
TMP-SMX prophylaxis versus no prophylaxis.
ASSESSMENT OF RISK OF BIAS
Risk Of Bias In Non-randomized Studies-of Exposure (ROBINS-E) for comparative studies; dedicated tool for non-comparative studies.
METHODS OF DATA SYNTHESIS
For our primary outcome (i.e. to determine the effect of TMP-SMX on the risk of nocardiosis), a one-step mixed-effects regression model was used to estimate the association between the outcome and the exposure. Univariate and multivariable unconditional regression models were used to adjust for the potential confounding effects. Certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
RESULTS
Individual data from three case-control studies were obtained (260 SOT recipients with nocardiosis and 519 uninfected controls). TMP-SMX prophylaxis was independently associated with a significantly decreased risk of nocardiosis (adjusted OR = 0.3, 95% CI 0.18-0.52, moderate certainty of evidence). Variables independently associated with an increased risk of nocardiosis were older age, current use of corticosteroids, high calcineurin inhibitor concentration, recent acute rejection, lower lymphocyte count, and heart transplant. Breakthrough infections (66/260, 25%) were generally susceptible to TMP-SMX (pooled proportion 98%, 95% CI 92-100).
CONCLUSIONS
In SOT recipients, TMP-SMX prophylaxis likely reduces the risk of nocardiosis. Resistance appears uncommon in case of breakthrough infection.
Topics: Humans; Breakthrough Infections; Nocardia Infections; Organ Transplantation; Retrospective Studies; Transplant Recipients; Trimethoprim, Sulfamethoxazole Drug Combination
PubMed: 37865337
DOI: 10.1016/j.cmi.2023.10.008 -
Military Medicine May 2024Antibiotic-resistant bacteria are a growing threat to civilian and military health today. Although infections were once easily treatable by antibiotics and wound... (Review)
Review
INTRODUCTION
Antibiotic-resistant bacteria are a growing threat to civilian and military health today. Although infections were once easily treatable by antibiotics and wound cleaning, the frequent mutation of bacteria has created strains impermeable to antibiotics and physical attack. Bacteria further their pathogenicity because of their ability to form biofilms on wounds, medical devices, and implant surfaces. Methods for treating biofilms in clinical settings are limited, and when formed by antibiotic-resistant bacteria, can generate chronic infections that are recalcitrant to available therapies. Bacteriophages are natural viral predators of bacteria, and their ability to rapidly destroy their host has led to increased attention in potential phage therapy applications.
MATERIALS AND METHODS
The present article sought to address a knowledge gap in the available literature pertaining to the usage of bacteriophage in clinically relevant settings and the resolution of infections particular to military concerns. PRISMA guidelines were followed for a systematic review of available literature that met the criteria for analysis and inclusion. The research completed for this review article originated from the U.S. Military Academy's library "Scout" search engine, which complies results from 254 available databases (including PubMed, Google Scholar, and SciFinder). The search criteria included original studies that employed bacteriophage use against biofilms, as well as successful phage therapy strategies for combating chronic bacterial infections. We specifically explored the use of bacteriophage against antibiotic- and treatment-resistant bacteria.
RESULTS
A total of 80 studies were identified that met the inclusion criteria following PRISMA guidelines. The application of bacteriophage has been demonstrated to robustly disrupt biofilm growth in wounds and on implant surfaces. When traditional therapies have failed to disrupt biofilms and chronic infections, a combination of these treatments with phage has proven to be effective, often leading to complete wound healing without reinfection.
CONCLUSIONS
This review article examines the available literature where bacteriophages have been utilized to treat biofilms in clinically relevant settings. Specific attention is paid to biofilms on implant medical devices, biofilms formed on wounds, and clinical outcomes, where phage treatment has been efficacious. In addition to the clinical benefit of phage therapies, the military relevance and treatment of combat-related infections is also examined. Phages offer the ability to expand available treatment options in austere environments with relatively low cost and effort, allowing the impacted warfighter to return to duty quicker and healthier.
Topics: Biofilms; Humans; Bacteriophages; Phage Therapy
PubMed: 37847552
DOI: 10.1093/milmed/usad385 -
Clinical Laboratory Oct 2023Acinetobacter baumannii produce biofilm and efflux pumps. This systematic review study aimed to provide new strategies to inhibit the efflux pumps and biofilm in A.... (Review)
Review
BACKGROUND
Acinetobacter baumannii produce biofilm and efflux pumps. This systematic review study aimed to provide new strategies to inhibit the efflux pumps and biofilm in A. baumannii using nanoparticles.
METHODS
In this research, analyses from 2000 to February 24, 2022, were performed by the Statement of Preferred Reporting Items for Systematic Reviews (PRISMA). Keywords include Acinetobacter baumannii (A. baumannii) AND (biofilm) AND (anti-biofilm activity) AND (nanoparticles) AND (solid lipid NPS) AND (lipid nanocarriers), and in other searches include Acinetobacter baumannii (A. baumanni) AND (efflux pumps) AND (nanoparticles) AND (solid lipid NPS) AND (lipid nanocarriers). Searches were conducted in English databases, including Science Direct, PubMed, Scopus, Ovid, and Cochrane.
RESULTS
At first, 136 studies were extracted, but after removing duplicates, 116 cases remained for further analysis. After evaluating the title and abstract of each study, 95 unrelated studies were excluded. The remaining 25 studies were reviewed based on full texts. Considering the inclusion/exclusion criteria, 19 studies were selected. In this study, metal nanoparticles were the most used nanoparticles for anti-biofilm and efflux pump purposes, and among these nanoparticles, silver nanoparticles (AgNPs) contributed the most.
CONCLUSIONS
The present study shows that nanoparticles have potential and significant effects in inhibiting biofilm and efflux pumps in A. baumannii isolates, which researchers can consider in light of the increasing prevalence of antibiotic resistance.
Topics: Humans; Anti-Bacterial Agents; Membrane Transport Proteins; Acinetobacter baumannii; Metal Nanoparticles; Silver; Biofilms; Lipids; Microbial Sensitivity Tests; Drug Resistance, Multiple, Bacterial; Bacterial Proteins
PubMed: 37844038
DOI: 10.7754/Clin.Lab.2023.230227 -
Journal of Dental Sciences Oct 2023Oral infection is a common clinical symptom. While antibiotics are widely employed as the primary treatment for oral diseases, the emergence of drug-resistant bacteria... (Review)
Review
Oral infection is a common clinical symptom. While antibiotics are widely employed as the primary treatment for oral diseases, the emergence of drug-resistant bacteria has necessitated the exploration of alternative therapeutic approaches. One such modality is antimicrobial photodynamic therapy (aPDT), which utilizes light and photosensitizers. Indeed, aPDT has been used alone or in combination with other treatment options dealing with periodontal disease for the elimination of biofilms from bacterial community to achieve bone formation and/or tissue regeneration. In this review article, in addition to factors affecting the efficacy of aPDT, various photosensitizers, the latest technology and perspectives on aPDT are discussed in detail. More importantly, the article emphasizes the novel design and clinical applications of photosensitizers, as well as the synergistic effects of chemical and biomolecules with aPDT to achieve the complete eradication of biofilms and even enhance the biological performance of tissues surrounding the treated oral area.
PubMed: 37799910
DOI: 10.1016/j.jds.2023.07.002 -
Pharmaceuticals (Basel, Switzerland) Sep 2023: Probiotic microorganisms, commonly used to bolster gut health, might also have benefits for dental health, according to certain studies. Probiotics (PBs) are... (Review)
Review
: Probiotic microorganisms, commonly used to bolster gut health, might also have benefits for dental health, according to certain studies. Probiotics (PBs) are associated with reducing cariogenic pathogens and protecting against periodontal diseases, although the exact way they function in the mouth is not fully clear. Our study aimed to explore the use of PBs to improve oral health, focusing on issues such as cavities, gum disease, bad breath, mucositis, and periimplantitis. : We utilized the Boolean keywords "Probiotics" AND "Oral health" to search the databases of PubMed, Scopus, and Web of Science. The search was restricted to English-language papers published from 1 January 2019 to 13 April 2023. : A total of 3460 articles were found through our computerized search. After removing duplicates, reviewing the papers, and determining their relevance, 12 were selected for inclusion. : Assessing how bacteria in food or dietary supplements might alter the stable oral microbiota is a complex task. Although probiotic microorganisms have been found to have proven therapeutic benefits, their application in dental health is not yet solidly backed by evidence. Further research is necessary to thoroughly understand the long-term effects of probiotic bacteria on the oral environment, including their ability to colonize and form biofilms.
PubMed: 37765121
DOI: 10.3390/ph16091313