Exploring the Interplay between COVID-19 and Gut Health: The Potential Role of Prebiotics and Probiotics in Immune Support.

The COVID-19 pandemic has profoundly impacted global health, leading to extensive research focused on developing strategies to enhance outbreak response and mitigate the disease's severity. In the aftermath of the pandemic, attention has shifted towards understanding and addressing long-term health implications, particularly in individuals experiencing persistent symptoms, known as long COVID. Research into potential interventions to alleviate long COVID symptoms has intensified, with a focus on strategies to support immune function and mitigate inflammation. One area of interest is the gut microbiota, which plays a crucial role in regulating immune responses and maintaining overall health. Prebiotics and probiotics, known for their ability to modulate the gut microbiota, have emerged as potential therapeutic agents in bolstering immune function and reducing inflammation. This review delves into the intricate relationship between long COVID, the gut microbiota, and immune function, with a specific focus on the role of prebiotics and probiotics. We examine the immune response to long COVID, emphasizing the importance of inflammation and immune regulation in the persistence of symptoms. The potential of probiotics in modulating immune responses, including their mechanisms in combating viral infections such as COVID-19, is discussed in detail. Clinical evidence supporting the use of probiotics in managing long COVID symptoms is summarized, highlighting their role as adjunctive therapy in addressing various aspects of SARS-CoV-2 infection and its aftermath.

Kodamaea ohmeri Leg Skin Ulcer Infection in an Immunocompetent Patient: A Case Report.

INTRODUCTION: Kodamaea ohmeri is an emerging fungus recognised as an important pathogen in immunocompromised hosts, responsible for life-threatening infections. CASE PRESENTATION: We describe a case of a 69-year-old immunocompetent man with a long history of leg skin ulcers infected by K. ohmeri. This is the first case of leg wounds infected by K. ohmeri in an immunocompetent patient. The infection was successfully treated with voriconazole 200 mg daily. CONCLUSION: Though rare, K. ohmeri should be considered in patients with skin ulcers that are poorly responsive to medical treatment, even if not immunocompromised.

Review Article title: Natural Compounds with Antimicrobial Activities in oral Candida infections during head and neck radiotherapy.

BACKGROUNDS: Oral colonization and infections are frequently observed in patients during and soon after radiation therapy (RT). Infective mucositis is a common side effect associated with cancer therapy, characterized by an inflammation of the oral mucous membranes with histological mucosal and submucosal changes. Ulcerative mucositis is responsible for significant pain, impairing the patient's nutritional intake and leading to local or systemic infections promoting mycosis due to several species of the genus Candida. According to international guidelines, treatment of candidiasis depends on the infection site and patient's condition. SUMMARY: Recently several studies have shown the protective role of natural compounds counteracting the activity of Candida biofilms. The aim of this review is to discuss the antimicrobial activities of natural compounds in fungal infections, especially Candida spp., during and soon after radiotherapy. Indeed new molecules are being discovered and assessed for their capacity to control Candida spp. growth and, probably in the future, will be used to treat oral candidiasis, overall, during radiotherapy. This review reports several preliminary data about preclinical and clinical evidence of their efficacy in the prevention and/or treatment of mucositis due to Radiotherapy with a brief description of the natural compounds with anti-Candida activities. KEY MESSAGES: The increase in the resistance to the available antifungal drugs related to Candida spp. infections increased as well as drug interactions, urging the development of innovative and more effective agents with antifungal action. Recent preclinical and clinical studies are identifying natural substances with anti-inflammatory and antifungal activity that could be tested in the prevention of candidiasis in patients undergoing radiotherapy. Further studies are needed to confirm these preliminary data.

Staphylococcus aureus Infection: Pathogenesis and Antimicrobial Resistance.

Staphylococcus aureus, a Gram-positive, coagulase-positive pathogen belonging to the family Staphylococcaceae with a spherical shape that forms grape-like clusters, is a commensal that is often present asymptomatically on parts of the human body [...].

Meningococcal Conjunctivitis in a 54-Year-Old Man: Case Report and Review of the Literature.

Neisseria meningitidis represents an uncommon pathogen of acute bacterial conjunctivitis. In this brief report, we describe a case of meningococcal conjunctivitis in an immunocompetent adult male, with a review of the literature. The patient went to the outpatient ophthalmology clinic complaining of severe ocular discomfort, burning, and redness for more than 2 weeks and, at slit lamp examination, he was diagnosed with a mild conjunctivitis. Microbiology cultures of ocular swabs revealed the growth of colonies, as pure culture, identified as N. meningitidis of serogroup B. A diagnosis of primary meningococcal conjunctivitis was made and treatment of patient with intramuscular injections of ceftriaxone in addition to topical moxifloxacin eye drops for 2 weeks led to clinical improvement and, finally, to a complete recovery, in accordance with microbiological findings. Ophthalmologists must be aware of the possibility of primary meningococcal conjunctivitis cases, even uncommon, and the need to treat with systemic antibiotics and their close contacts with adequate antibiotic chemoprophylaxis.

Microbiological Laboratory Diagnosis of Human Brucellosis: An Overview.

Brucella spp. are Gram-negative, non-motile, non-spore-forming, slow-growing, facultative intracellular bacteria causing brucellosis. Brucellosis is an endemic of specific geographic areas and, although underreported, represents the most common zoonotic infection, with an annual global incidence of 500,000 cases among humans. Humans represent an occasional host where the infection is mainly caused by B. melitensis, which is the most virulent; B. abortus; B. suis; and B. canis. A microbiological analysis is crucial to identifying human cases because clinical symptoms of human brucellosis are variable and aspecific. The laboratory diagnosis is based on three different microbiological approaches: (i) direct diagnosis by culture, (ii) indirect diagnosis by serological tests, and (iii) direct rapid diagnosis by molecular PCR-based methods. Despite the established experience with serological tests and highly sensitive nucleic acid amplification tests (NAATs), a culture is still considered the "gold standard" in the laboratory diagnosis of brucellosis due to its clinical and epidemiological relevance. Moreover, the automated BC systems now available have increased the sensitivity of BCs and shortened the time to detection of Brucella species. The main limitations of serological tests are the lack of common interpretative criteria, the suboptimal specificity due to interspecies cross-reactivity, and the low sensitivity during the early stage of disease. Despite that, serological tests remain the main diagnostic tool, especially in endemic areas because they are inexpensive, user friendly, and have high negative predictive value. Promising serological tests based on new synthetic antigens have been recently developed together with novel point-of-care tests without the need for dedicated equipment and expertise. NAATs are rapid tests that can help diagnose brucellosis in a few hours with high sensitivity and specificity. Nevertheless, the interpretation of NAAT-positive results requires attention because it may not necessarily indicate an active infection but rather a low bacterial inoculum, DNA from dead bacteria, or a patient that has recovered. Refined NAATs should be developed, and their performances should be compared with those of commercial and home-made molecular tests before being commercialized for the diagnosis of brucellosis. Here, we review and report the most common and updated microbiological diagnostic methods currently available for the laboratory diagnosis of brucellosis.

Repurposing the Veterinary Antibiotic Apramycin for Antibacterial and Antibiofilm Activity Against Pseudomonas aeruginosa From Cystic Fibrosis Patients.

OBJECTIVES: To evaluate the in vitro antibacterial, antibiofilm, and antivirulence activities of apramycin, comparatively to tobramycin, against a set of P. aeruginosa from chronically infected cystic fibrosis (CF) patients. METHODS: The activity of antibiotics against planktonic cells was assessed by performing MIC, MBC, and time-kill assays. The activity against mature biofilms was evaluated, in a microtiter plate, both in terms of dispersion (crystal violet assay) and residual viability (viable cell count). The effect of drug exposure on selected P. aeruginosa virulence genes expression was assessed by real-time Reverse Transcription quantitative PCR (RT-qPCR). RESULTS: Apramycin MIC90 and MBC90 values were found at least fourfold lower than those for tobramycin. A comparable trend was observed for mucoid strains. Only 4 out of 24 strains (16.6%) showed an apramycin MIC higher than the epidemiological cut-off value of 64 mg/L, whereas a higher resistance rate was observed for tobramycin (62.5%; p < 0.01 vs. apramycin). In time-kill analyses, both aminoglycosides were found bactericidal, although apramycin showed a more rapid effect and did not allow for regrowth. Apramycin generally stimulated biofilm biomass formation, whereas tobramycin showed opposite trends depending on the strain tested. Both drugs caused a highly significant, dose-dependent reduction of biofilm viability, regardless of strain and concentration tested. The exposure to apramycin and tobramycin caused increased expression of mexA and mexC (multidrug efflux pumps), whereas tobramycin specifically increased the expression of aprA (alkaline protease) and toxA (exotoxin A). Neither apramycin nor tobramycin showed cytotoxic potential toward IB3-1 bronchial epithelial CF cells. CONCLUSION: Our results warrant future pharmacokinetic and pharmacodynamic studies for supporting the rationale to repurpose apramycin, a veterinary aminoglycoside, for CF lung infections.

Rapid Detection of Methicillin-Resistant Staphylococcus aureus Directly from Blood for the Diagnosis of Bloodstream Infections: A Mini-Review.

Staphylococcus aureus represents a major human pathogen able to cause a number of infections, especially bloodstream infections (BSI). Clinical use of methicillin has led to the emergence of methicillin-resistant S. aureus (MRSA) and MRSA-BSI have been reported to be associated with high morbidity and mortality. Clinical diagnosis of BSI is based on the results from blood culture that, although considered the gold standard method, is time-consuming. For this reason, rapid diagnostic tests to identify the presence of methicillin-susceptible S. aureus (MSSA) and MRSA isolates directly in blood cultures are being used with increasing frequency to rapidly commence targeted antimicrobial therapy, also in the light of antimicrobial stewardship efforts. Here, we review and report the most common rapid non-molecular and molecular methods currently available to detect the presence of MRSA directly from blood.

Whole genome sequencing of carbapenem-resistant Klebsiella pneumoniae: evolutionary analysis for outbreak investigation.

Aim: Carbapenemase-resistant Enterobacteriaceae represents a major concern in hospital setting. Materials & methods: The evolutionary history of carbapenem-resistant Klebsiella pneumonia strains was analyzed by core genome multilocus sequence typing and Bayesian phylogenesis by whole genomes sequencing. Results: A great increase carbapenem-resistant K.pneumoniae causing blood stream infection was observed in the years 2015-2016. At multilocus sequence typing (MLST), they were prevalently ST512 and ST101. ST512 were core genome (cg)MLST 53, while ST101 mainly cgMLST453. The minimum-spanning tree, based on cgMLST, showed strains clustering based on the different STs. By Bayesian phylogenetic analysis, maximum clade credibility tree showed that strains were introduced in the year 2005 with the most probable location in the ICU ward. Two outbreaks by ST101 and ST512 strains with Tower T8 as the probable location were evidenced. Conclusion: Molecular epidemiology is a powerful tool to track the way of transmission of resistant bacteria within the hospital setting.

Clonal Diversity, Biofilm Formation, and Antimicrobial Resistance among Stenotrophomonas maltophilia Strains from Cystic Fibrosis and Non-Cystic Fibrosis Patients.

The intrinsic antibiotic resistance of Stenotrophomonas maltophilia, along with its ability to form biofilm both on abiotic surfaces and host tissues, dramatically affects the efficacy of the antibiotic therapy. In this work, 85 S. maltophilia strains isolated in several hospital of central Italy and from several clinical settings were evaluated for their genetic relatedness (by pulsed-field gel electrophoresis, PFGE), biofilm formation (by microtiter plate assay), and planktonic antibiotic resistance (by Kirby-Bauer disk diffusion technique). The S. maltophilia population showed a high genetic heterogeneity: 64 different PFGE types were identified, equally distributed in cystic fibrosis (CF) and non-CF strains, and some consisted of multiple strains. Most of the strains (88.2%) were able to form biofilm, although non-CF strains were significantly more efficient than CF strains. CF strains produced lower biofilm amounts than non-CF strains, both those from respiratory tracts and blood. Non-CF PFGE types 3 and 27 consisted of strong-producers only. Cotrimoxazole and levofloxacin were the most effective antibiotics, being active respectively against 81.2% and 72.9% of strains. CF strains were significantly more resistant to piperacillin/tazobactam compared to non-CF strains (90% versus 53.3%), regardless of sample type. Among respiratory strains, cotrimoxazole was more active against non-CF than CF strains (susceptibility rates: 86.7% versus 75%). The multidrug resistant phenotype was significantly more prevalent in CF than non-CF strains (90% versus 66.7%). Overall, the multidrug-resistance level was negatively associated with efficiency in biofilm formation. Our results showed, for the first time, that in S. maltophilia both classical planktonic drug resistance and the ability of biofilm formation might favor its dissemination in the hospital setting. Biofilm formation might in fact act as a survival mechanism for susceptible bacteria, suggesting that clinical isolates should be routinely assayed for biofilm formation in diagnostic laboratories.

Collection, transport and storage procedures for blood culture specimens in adult patients: recommendations from a board of Italian experts.

Bloodstream infections (BSIs) remain a potentially life-threatening condition. The gold standard for the diagnosis of BSI is still blood cultures (BCs), and the diagnostic yield depends on clinical and technical factors that have an impact on collection and transportation. Hence, monitoring of the entire pre-analytical process from blood collection to transportation to the microbiology laboratory is critical. To optimize the clinical impact of the diagnostic and therapeutic procedures, a multidisciplinary approach and univocal protocols are mandatory. A board of specialists discussed the available evidence on the pre-analytical process and produced the present document to guide physicians and nurses on the ideal execution of BC: (1) timing and preparation for blood collection; (2) skin antisepsis; (3) blood volume; (4) sampling method and safety; (5) medium to be used; (6) time to BC transportation; and (7) quality assurance and quality management.

Evaluation of in vitro activity of ceftolozane-tazobactam compared to other antimicrobial agents against Pseudomonas aeruginosa isolates from cystic fibrosis patients.

The in vitro activity of ceftolozane-tazobactam (C-T) was evaluated comparatively to other antibiotics against 188 Pseudomonas aeruginosa isolates collected from cystic fibrosis (CF) patients. Overall, the activity of C-T was comparable to colistin (susceptibility rate: 85.1% vs. 89.4%) but significantly higher than other antimicrobials. Particularly, C-T was active against 70% of meropenem nonsusceptible isolates and 64.1% of those nonsusceptible to beta-lactams. C-T was active against 70%, 58.1%, and 100% of multidrug-resistant, extensively drug-resistant (XDR), and pandrug-resistant isolates, respectively. No differences in C-T activity were found between isolates from children and adult patients, except for XDR ones significantly more susceptible in older patients. C-T and colistin exhibited comparable susceptibility rate (91.1% vs. 86.7%) also against 68 isolates collected during pulmonary exacerbations. Activity of C-T towards mucoid isolates was less than colistin (82.9% vs. 97.6%) but higher compared with other antibiotics. C-T represents a promising agent for treating CF lung infections.

An Overview on Streptococcus bovis/Streptococcus equinus Complex Isolates: Identification to the Species/Subspecies Level and Antibiotic Resistance.

Streptococcus bovis/Streptococcus equinus complex (SBSEC), a non-enterococcal group D Streptococcus spp. complex, has been described as commensal bacteria in humans and animals, with a fecal carriage rate in humans varying from 5% to over 60%. Among streptococci, SBSEC isolates represent the most antibiotic-resistant species-with variable resistance rates reported for clindamycin, erythromycin, tetracycline, and levofloxacin-and might act as a reservoir of multiple acquired genes. Moreover, reduced susceptibility to penicillin and vancomycin associated with mobile genetic elements have also been detected, although rarely. Since the association of SBSEC bacteremia and colon lesions, infective endocarditis and hepatobiliary diseases has been established, particularly in elderly individuals, an accurate identification of SBSEC isolates to the species and subspecies level, as well as the evaluation of antibiotic resistance, are needed. In this paper, we reviewed the major methods used to identify SBSEC isolates and the antimicrobial resistance rates reported in the scientific literature among SBSEC species.

Adhesion and biofilm formation by Staphylococcus aureus clinical isolates under conditions relevant to the host: relationship with macrolide resistance and clonal lineages.

PURPOSE: Staphylococcus aureus isolates, collected from various clinical samples, were analysed to evaluate the contribution of the genetic background of both erythromycin-resistant (ERSA) and -susceptible (ESSA) S. aureus strains to biofilm formation. METHODS: A total of 66 ESSA and 43 ERSA clinical isolates were studied for adhesiveness and biofilm formation under different atmospheres. All isolates were evaluated for phenotypic and genotypic macrolide resistance, and for clonal relatedness by pulsed-field gel electrophoresis (PFGE), and by spa typing on representative isolates. RESULTS: A high genetic heterogeneity was encountered, although 10 major PFGE types accounted for 86 % with a few small spatially and temporally related clusters. Overall, biofilm formation under anoxia was significantly lower than under oxic and micro-aerophilic atmospheres. Biofilm formation by ESSA was significantly higher compared to ERSA under oxic and micro-aerophilic conditions. Adhesiveness to plastic was significantly higher among respiratory tract infection isolates under micro-aerophilic conditions, while surgical site infection isolates formed significantly higher biomass of biofilm under oxic and micro-aerophilic atmospheres compared to anoxia. Pulsotype 2 and 4 strains formed significantly higher biofilm biomass than pulsotype 1, with strains belonging to CC8 forming significantly more compared to those belonging to CC5, under both oxic and micro-aerophilic atmospheres. CONCLUSIONS: S. aureus biofilm formation appears to be more efficient in ESSA than ERSA, associated with specific S. aureus lineages, mainly CC8 and CC15, and affected by atmosphere. Further studies investigating the relationship between antibiotic resistance and biofilm formation could prove useful in the development of new strategies for the management of S. aureus infections.

Prevalent emm Types among Invasive GAS in Europe and North America since Year 2000.

BACKGROUND: Streptococcus pyogenes or group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections, from uncomplicated to more severe and invasive diseases with high mortality and morbidity. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern; for this purpose the M protein gene (emm) gene typing is the most widely used genotyping method, with more than 200 emm types recognized. Molecular epidemiological data have been also used for the development of GAS M protein-based vaccines. METHODS: The aim of this paper was to provide an updated scenario of the most prevalent GAS emm types responsible for invasive infections in developed countries as Europe and North America (US and Canada), from 1st January 2000 to 31st May 2017. The search, performed in PubMed by the combined use of the terms ("emm") and ("invasive") retrieved 264 articles, of which 38 articles (31 from Europe and 7 from North America) met the inclusion criteria and were selected for this study. Additional five papers cited in the European articles but not retrieved by the search were included. RESULTS: emm1 represented the dominant type in both Europe and North America, replaced by other emm types in only few occasions. The seven major emm types identified (emm1, emm28, emm89, emm3, emm12, emm4, and emm6) accounted for approximately 50-70% of the total isolates; less common emm types accounted for the remaining 30-50% of the cases. Most of the common emm types are included in either one or both the 26-valent and 30-valent vaccines, though some well-represented emm types found in Europe are not. CONCLUSION: This study provided a picture of the prevalent emm types among invasive GAS (iGAS) in Europe and North America since the year 2000 onward. Continuous surveillance on the emm-type distribution among iGAS infections is strongly encouraged also to determine the potential coverage of the developing multivalent vaccines.

Infection of recurrent calcaneal ulcer caused by a biofilm-producer Myroides odoratimimus strain.

We report a case of recurrent post-traumatic ulcer infection due to Myroides odoratimimus in an immunocompromised male. We have also reviewed the medical literature on isolated M. odoratimimus infections. The strain, isolated from ulcer discharge, was multidrug-resistant and treatment with meropenem, based on susceptibility testing, led to resolution of infection. The strain was also able to form a relevant amount of biofilm over time, thus suggesting a possible role of sessile communities in the chronicization of infection. To our knowledge, this is the first description of recurrent ulcer infection caused by a biofilm-producer M. odoratimimus strain. This case reminds us of the need to consider uncommon pathogens as etiology of skin and soft tissue infections, especially in immunocompromised patients. Further, since the treatment of infections due to M. odoratimimus is often difficult both due to multidrug resistance and scarce clinical experience, antibiotic therapy should be adapted to in vitro susceptibility testing.

Impact of pneumococcal conjugate vaccine (PCV7 and PCV13) on pneumococcal invasive diseases in Italian children and insight into evolution of pneumococcal population structure.

BACKGROUND: The use of PCV7 for children immunization was gradually implemented in the Italian regions starting from 2006 and was replaced by PCV13 in 2010-2011. In this study we aimed to assess the PCV impact on invasive pneumococcal diseases (IPD) incidence, serotype distribution and antibiotic resistance in Italian children under 5years old. METHODS: All IPD cases in children from 5 Italian regions (Emilia-Romagna, Lombardia, A. P. Bolzano, A. P. Trento, and Piemonte) reported through the nationwide surveillance system during 2008-2014 were included in this study. Pneumococcal isolates were subjected to serotyping, antibiotic susceptibility testing, and clonal analysis according to standard methods. RESULTS: During the study period overall IPD incidence decreased from 7.8 cases/100,000 inhabitants in 2008 to 3.0 cases/100,000 in 2014 (61% decrease, P<0.001). In particular, from 2008 to 2014, PCV7-type IPD decreased from 2.92 to 0.13 cases/100,000 inhabitants (95% decrease, P<0.001) while PCV13-non-PCV7 type IPD decreased from 3.2 to 0.89 cases/100,000 inhabitants (72% decrease, P=0.008). Conversely, non-vaccine serotype (NVS) IPD increased overtime, becoming more common than PCV13 serotype IPD in 2013-2014. Emergent NVS 24F and 12F were the most prevalent in 2014. Antibiotic resistance testing revealed an overall increasing trend in penicillin resistance, from 14% in 2008 to 23% in 2014. Erythromycin resistance showed a downward trend, from 38% in 2008 to 27% in 2014. While in 2008 PCV13 serotypes were the major responsible for antibiotic resistance, during the following years antimicrobial resistance due to NVS increased, mainly as a result of expansion of pre-existing clones. CONCLUSIONS: Both PCVs led to a substantial decrease in vaccine-related IPD incidence in the children population. However NVS-related IPD increased, becoming the most prevalent in the last two-years period. Continuous surveillance is an essential tool to monitor evolution of pneumococcal population causing IPD in children.