Species of the Enterobacter cloacae complex are widely encountered in nature, but they can act as pathogens. The biochemical and molecular studies on E. cloacae have shown genomic heterogeneity, ...comprising six species: Enterobacter cloacae, Enterobacter asburiae, Enterobacter hormaechei, Enterobacter kobei, Enterobacter ludwigii and Enterobacter nimipressuralis, E. cloacae and E. hormaechei are the most frequently isolated in human clinical specimens. Phenotypic identification of all species belonging to this taxon is usually difficult and not always reliable; therefore, molecular methods are often used. Although the E. cloacae complex strains are among the most common Enterobacter spp. causing nosocomial bloodstream infections in the last decade, little is known about their virulence-associated properties. By contrast, much has been published on the antibiotic-resistance features of these microorganisms. In fact, they are capable of overproducing AmpC β-lactamases by derepression of a chromosomal gene or by the acquisition of a transferable ampC gene on plasmids conferring the antibiotic resistance. Many other resistance determinants that are able to render ineffective almost all antibiotic families have been recently acquired. Most studies on antimicrobial susceptibility are focused on E. cloacae, E. hormaechei and E. asburiae; these studies reported small variations between the species, and the only significant differences had no discriminating features.
•Essential oils were loaded in polymeric polycaprolactone nanocapsules (EO-NCs).•EO-NCs exhibited monomodal size distribution, low PDI, high EE% and stability.•Nanoencapsulation of essential oils ...enhances their antimicrobial activity.•EO-NCs as a natural alternative to food chemical preservatives.
The aim of this work is the encapsulation of essential oils (EOs) in polymeric nanocapsules (NCs), in order to enhance their antimicrobial activity against food-borne pathogens. Thymus capitatus and Origanum vulgare EOs were selected for their different chemical composition, carvacrol (73%) and thymol (44%) being the major constituent, respectively. Polymeric poly(ɛ-caprolactone) (PCL) nanocapsules loaded with EOs were prepared by a nanoprecipitation method. The EO-NCs showed monomodal distribution with diameter size 171 and 175 nm, high efficiency of encapsulation and stability with high retention of EOs at both 4 °C and 40 °C, for a period of at least 30 days. The antimicrobial activity of EO-NCs against food-borne pathogens was higher than that of the corresponding pure essential oils and the NCs loaded with Thymus capitatus EO were the most active. Interestingly EO-NCs showed a bactericidal activity even at the minimum inhibitory concentrations (MICs). It makes them appealing as natural food preservatives.
Antibiotic resistance is a threat to human and animal health worldwide, and key measures are required to reduce the risks posed by antibiotic resistance genes that occur in the environment. These ...measures include the identification of critical points of control, the development of reliable surveillance and risk assessment procedures, and the implementation of technological solutions that can prevent environmental contamination with antibiotic resistant bacteria and genes. In this Opinion article, we discuss the main knowledge gaps, the future research needs and the policy and management options that should be prioritized to tackle antibiotic resistance in the environment.
Cancer is a multifactorial pathology and it represents the second leading cause of death worldwide. In the recent years, numerous studies highlighted the dual role of the gut microbiota in preserving ...host's health. Gut resident bacteria are able to produce a number of metabolites and bioproducts necessary to protect host's and gut's homeostasis. Conversely, several microbiota subpopulations may expand during pathological dysbiosis and therefore produce high levels of toxins capable, in turn, to trigger both inflammation and tumorigenesis. Importantly, gut microbiota can interact with the host either modulating directly the gut epithelium or the immune system. Numerous gut populating bacteria, called probiotics, have been identified as protective against the genesis of tumors. Given their capability of preserving gut homeostasis, probiotics are currently tested to help to fight dysbiosis in cancer patients subjected to chemotherapy and radiotherapy. Most recently, three independent studies show that specific gut resident species may potentiate the positive outcome of anti-cancer immunotherapy. The highly significant studies, uncovering the tight association between gut microbiota and tumorigenesis, as well as gut microbiota and anti-cancer therapy, are here described. The role of the
(LGG), as the most studied probiotic model in cancer, is also reported. Overall, according to the findings here summarized, novel strategies integrating probiotics, such as LGG, with conventional anti-cancer therapies are strongly encouraged.
Infections caused by Gram-positive bacteria are a major public health problem due to their increasing resistance to antibiotics.
Staphylococcus
and
Enterococcus
species’ resistance and pathogenicity ...are enhanced by their ability to form biofilm. The biofilm lifestyle represents a significant obstacle to treatment because bacterial cells become highly tolerant to a wide range of antimicrobial compounds normally effective against their planktonic forms. Thus, novel therapeutic strategies targeting biofilms are urgently needed. The lipoglycopeptide dalbavancin is a long-acting agent for treating acute bacterial skin and skin structure infections caused by a broad range of Gram-positive pathogens. Recent studies have shown promising activity of dalbavancin against Gram-positive biofilms, including methicillin-resistant
S. aureus
(MRSA), methicillin-resistant
S. epidermidis
(MRSE), and vancomycin-susceptible enterococci. This review outlines the mechanisms regulating biofilm development in
Staphylococcus
and
Enterococcus
species and the clinical impact of biofilm-related infections. In addition, it discusses the clinical implications and potential therapeutic perspectives of the long-acting drug dalbavancin against biofilm-forming Gram-positive pathogens.
The use of natural compounds with biocidal activity to fight the growth of bacteria responsible for foodborne illness is one of the main research challenges in the food sector. This study reports the ...preparation and physicochemical characterization of chitosan nanoparticles loaded with
(Th-CNPs) and
(Or-CNPs) essential oils. The nanosystems were obtained by ionotropic gelation technique with high encapsulation efficiency (80-83%) and loading capacity (26-27%). Nanoparticles showed a spherical shape, bimodal particle size distribution, and good stability (zeta potential values > 40 mV). The treatment of the nanosuspensions at different temperatures (4 and 40 °C) and storage times (7, 15, 21, and 30 days) did not affect their physicochemical parameters and highlights their reservoir ability for essential oils also under stressful conditions. Both Or-CNPs and Th-CNPs exhibited an enhanced bactericidal activity against foodborne pathogens (
,
,
) than pure essential oils. These ecofriendly nanosystems could represent a valid alternative to synthetic preservatives and be of interest for health and food safety.
The aim of this study was to address the involvement of PBP mutations in the bactericidal activity to novel cephalosporins, alone and in combination with daptomycin, in not-related ...multidrug-resistant methicillin-resistant Staphylococcus aureus strains isolated during a nationwide Italian survey. MICs determination and time-killing assays were performed and mecA, pbp1, pbp2, pbp3, pbp4, and gdpP genes were sequenced. Ten strains showed low-level resistance to ceftaroline and ceftobiprole. PBP2a sequence analysis identified four different mutations (N146K; N204K; T235I; E239K) uniquely present in the non-penicillin-binding domain (nPBD). Epidemiologically, this resistance was associated with the most widespread MDR Italian clone ST228-SCCmecI-t001/t041, confirming its proclivity to accumulate mutations, and it is also associated to substitutions in the GdpP signaling protein, involved in the maintenance of di-AMP balance, recently associated with resistance to beta-lactams. Despite these mutations, both drugs retained their potent in vitro bactericidal activity and showed a synergistic effect towards difficult-to-treat isolates.
Summary Staphylococcus aureus is a well adapted human pathogen, capable of living freely in the inanimate environment and spreading from person to person, existing as a colonizer or commensal, hiding ...in intracellular compartments and, most importantly, inducing various forms of human disease. Infections caused by S. aureus , above all by antibiotic-resistant strains, have reached epidemic proportions globally. The overall burden of staphylococcal disease caused by antibiotic-resistant S. aureus , particularly by the methicillin-resistant strains, is increasing in many countries, including Italy, in both healthcare and community settings. The widespread use of antibiotics has undoubtedly accelerated the evolution of S. aureus , which, acquiring multiple resistance genes, has become able to survive almost all antibiotic families; this evolution versus more resistant phenotypes has continued among the newer agents, including linezolid and daptomycin. The diminished clinical usefulness of vancomycin is seen as one of the most worrisome problems in many clinical settings and in many countries. In fact, the increasing spread of heteroresistant vancomycin-intermediate S. aureus (hVISA) and vancomycin intermediate (VISA) strains adds new problems, not only in terms of the treatment of severe infections sustained by these microorganisms, but also in the microbiological definition of susceptibility.
Challenges in the management of chronic wound infections Falcone, Marco; De Angelis, Barbara; Pea, Federico ...
Journal of global antimicrobial resistance.,
September 2021, 2021-09-00, 20210901, 2021-09-01, Volume:
26
Journal Article
Peer reviewed
Open access
•Distinction between chronic uninfected from infected wounds is challenging.•Culturing of all chronic wounds is inappropriate.•Debridement is an important step to facilitate the wound healing ...process.•Patients with chronic wound infections require a multidisciplinary approach.•Systemic antibiotics should not be limited to infected cases.
Chronic wound infections may delay the healing process and are responsible for a significant burden on healthcare systems. Since inappropriate management may commonly occur in the care of these patients, this review aims to provide a practical guide underlining actions to avoid in the management of chronic wound infections.
We performed a systematic review of the literature available in PubMed in the last 10 years, identifying studies regarding the management of patients with chronic wound infections. A panel of experts discussed the potential malpractices in this area. A list of ‘Don'ts’, including the main actions to be avoided, was drawn up using the ‘Choosing Wisely’ methodology.
In this review, we proposed a list of actions to avoid for optimal management of patients with chronic wound infections. Adequate wound bed preparation and wound antisepsis should be combined, as the absence of one of them leads to delayed healing and a higher risk of wound complications. Moreover, avoiding inappropriate use of systemic antibiotics is an important point because of the risk of selection of multidrug-resistant organisms as well as antibiotic-related adverse events.
A multidisciplinary team of experts in different fields (surgeon, infectious disease expert, microbiologist, pharmacologist, geriatrician) is required for the optimal management of chronic wound infections. Implementation of this approach may be useful to improve the management of patients with chronic wound infections.
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