SARS-CoV-2 mRNA vaccine BNT162b2 triggers a consistent cross-variant humoral and cellular response.

As the SARS-CoV-2 pandemic continues to rage worldwide, the emergence of numerous variants of concern (VOC) represents a challenge for the vaccinal protective efficacy and the reliability of commercially available high-throughput immunoassays. Our study demonstrates the administration of two doses of the BNT162b2 vaccine that elicited a robust SARS-CoV-2-specific immune response which was assessed up to 3 months after full vaccination in a cohort of 37 health care workers (HCWs). SARS-CoV-2-specific antibody response, evaluated by four commercially available chemiluminescence immunoassays (CLIA), was qualitatively consistent with the results provided by the gold-standard in vitro neutralization assay (NTA). However, we could not observe a correlation between the quantity of the antibody detected by CLIA assays and their neutralizing activity tested by NTA. Almost all subjects developed a SARS-CoV-2-specific T-cell response. Moreover, vaccinated HCWs developed a similar protective neutralizing antibodies response against the EU (B.1), Alpha (B.1.1.7), Gamma (P.1), and Eta (B.1.525) SARS-CoV-2 variants, while Beta (B.1.351) and Delta (B.1.617.2) strains displayed a consistent partial immune evasion. These results underline the importance of a solid vaccine-elicited immune response and a robust antibody titre. We believe that these relevant results should be taken into consideration in the definition of future vaccinal strategies.

Chagas disease knocks on our door: a cross-sectional study among Latin American immigrants in Milan, Italy.

OBJECTIVES: We aimed to assess the prevalence and risk factors for Chagas disease (CD) in Latin American immigrants and to evaluate the accuracy of diagnostic tests. Moreover, we offered to all positive subjects a complete free-of-charge clinical/instrumental evaluation as well as benznidazole treatment in order to stage the disease and verify drug tolerability. METHODS: A cross-sectional survey of CD among Latin Americans living in Milan and its metropolitan area was conducted between July 2013 and July 2014. Blood samples were tested for serologic evidence of CD together with a questionnaire covering demographic and clinical-epidemiological information. RESULTS: Forty-eight (9.6%) of the 501 tested subjects were conclusively diagnosed as having CD. The highest prevalence of CD was among those from Bolivia (43/169, 25.4%) and El Salvador (4/68, 5.9%). Older age (adjusted odds ratio (aOR)] 1.05, p =0.004), a Bolivian origin (aOR 8.80; p =0.003), being born in the department of Santa Cruz (aOR 3.72, p =0.047), having lived in mud houses (aOR 2.68; p =0.019), and having an affected relative (aOR 12.77, p =0.001) were independently associated with CD. The ARCHITECT Chagas test showed the highest sensitivity (100%) and specificity (99.8%). Twenty-nine of the subjects with CD (60.4%) underwent disease staging, 10 of whom (35.7%) showed cardiac and/or digestive involvement. Benznidazole treatment was associated with high frequency of adverse reactions (19/27, 70.4%) and permanent discontinuation (8/27, 29.6%). CONCLUSIONS: CD is highly prevalent among Bolivians and Salvadorans living in Milan. Regions with a large Latin American immigrant population should implement programmes of active detection and treatment.

Kinetic bactericidal activity of telithromycin, azithromycin and clarithromycin against respiratory pathogens.

The present study assessed the comparative in vitro killing kinetics of telithromycin, azithromycin and clarithromycin. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) were determined against Streptococcus pneumoniae, beta-haemolytic streptococci, Haemophilus influenzae and Moraxella catarrhalis strains characterized by different susceptibilities to beta-lactams and macrolides. For each bacterial species, representative strains were chosen for time-kill studies. Telithromycin showed high activity against all the tested strains with MIC ranging from < or = 0.004 to 0.5 mg/L for streptococci, from 0.008 to 8 mg/L for H. influenzae, and from 0.008 to 0.5 mg/L for M. catarrhalis. In time-kill studies, telithromycin showed an overall superior bactericidal activity in respect to macrolides, particularly against resistant strains. In conclusion, telithromycin proved to possess bactericidal activity against a wide range of respiratory pathogens, including strains resistant to common macrolides.

In vitro synergy and selection of resistance by fluoroquinolones plus amikacin or beta-lactams against extended-spectrum beta-lactamase-producing Escherichia coli.

This study compared the potential synergy of levofloxacin and ciprofloxacin in combination with cefepime, ceftazidime, imipenem, piperacillin/tazobactam or amikacin, against extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli by using checkerboard and time kill studies. Moreover, selection of resistance was determined by frequency of mutations and by calculating the increase in minimum inhibitory concentrations (MICs) after five serial subcultures on antibiotic-containing plates. Synergy occurred more often with levofloxacin combined with imipenem (7/10 strains) and with levofloxacin or ciprofloxacin with amikacin (10/10) than for the other combinations. Time kill studies showed synergy for levofloxacin combined with amikacin, ceftazidime, imipenem or piperacillin/tazobactam, and for ciprofloxacin combined with amikacin, cefepime or imipenem. Antibiotic combinations selected for resistance less frequently than antibiotics alone. Mutation frequency was <10(-12) for all combinations. In conclusion, the combination of a fluoroquinolone with a beta-lactam or amikacin may provide improved antimicrobial activity and help limit the occurrence of resistance in ESBL-producing E. coli strains.

Comparative evaluation of the new xTAG GPP multiplex assay in the laboratory diagnosis of acute gastroenteritis. Clinical assessment and potential application from a multicentre Italian study.

OBJECTIVE: Gastroenteritis caused by a single pathogen or multiple pathogens remains a major diagnostic challenge for the laboratory. The treatment of diarrhoea is based on microbiological results. Diagnosis is achieved using different laboratory techniques that have variable sensitivity and specificity. xTAG GPP is a new multiplex PCR assay that simultaneously detects 15 different pathogens responsible for diarrhoea. The results of the first multicentre study in Italy to evaluate the potential clinical application of the GPP assay in the laboratory diagnosis of diarrhoea are reported here. METHODS: Faeces specimens (N=664) from hospitalized patients were tested with the GPP assay using a Luminex 200 instrument. All specimens were run using comparator methods following a routine algorithm: culture for bacteria, enzyme immunoassay and PCR for viruses, and microscopy for parasites. RESULTS: Of the samples tested with the GPP, 53.61% (356/664) gave positive results, as compared to 45.33% by routine testing. Of the positive specimens, 34.55% showed the presence of genomic DNA from multiple pathogens. The Luminex method showed an increase in the percentage of positivity of 8.28%. CONCLUSIONS: The GPP assay can be considered a helpful tool for the detection of gastrointestinal pathogens, with a hands-on time of 5h; it provides accurate data for the clinical management of hospitalized patients and for epidemiological surveillance.

Inhibition of in vitro growth of enteropathogens by new Lactobacillus isolates of human intestinal origin.

Three human Lactobacillus strains, coded B21060, B21070 and B21190, have recently been isolated. The strains show a series of features (acid and bile resistance, adhesion to various types of mucosal cell) which make them particularly promising for the preparation of probiotic products. In the present study, the ability of the strains to inhibit the growth of pathogens in coculture was investigated. Lactobacilli were incubated simultaneously or after one overnight growth with enterotoxigenic Escherichia coli, Salmonella enteritidis or Vibrio cholerae. After 24 and 48 h, bacterial counts of the pathogens and of the lactobacilli were performed. The results showed that these Lactobacillus strains inhibited the in vitro growth of E. coli and S. enteritidis under both conditions. Moreover, a cumulative effect was observed for mixtures of lactobacilli. In contrast, no significant inhibition of Vibrio cholerae growth was observed, provided that the pH of the medium was kept constant. The presence of the pathogens did not affect the growth of the Lactobacillus strains. Moreover, each of the Lactobacillus strains showed coaggregation ability with two pathogenic E. coli strains, namely ATCC 25922 and ATCC 35401.

The use of probiotics in medical practice.

Probiotics are defined as living organisms, beneficial to health when ingested. Different species of microorganisms such as lactic acid bacteria or yeasts have been proposed for human use. These microorganisms differ from each other and it is, therefore, unlikely that they will act in the same way. Probiotics could be used for several conditions such as diarrhoea, candidal vaginitis, urinary tract infections, immune disorders, lactose intolerance, hypercholesterolaemia and food allergy. The effects of probiotics in some of these conditions have been directly observed, in others it has been only suggested on the basis of in vitro studies and from experimental animal models. Controlled trials are needed to determine the scientific basis for their use, the correct formulation and ways of administration in different clinical situations.

Review of probiotics available to modify gastrointestinal flora.

There is evidence that the oral consumption of micro-organisms produces a protective effect on the gut flora. A significant number of studies suggests that probiotics might have beneficial effects on several microbial disorders of the gut, but it is very difficult to define the clinical efficacy of such products. In this review, we report the results of studies on traveller's diarrhoea (TD), antibiotic associated diarrhoea (AAD) and acute diarrhoea (AD) in which various probiotic preparations have been used in controlled trials and been shown to have a beneficial therapeutic or prophylactic effect.

Serum and lung levels of thiamphenicol after administration of its glycinate N-acetylcysteinate ester in experimentally infected guinea pigs.

Thiamphenicol is an analogue of chloramphenicol and is characterised by a broad spectrum of action. In this study, serum and lung levels of thiamphenicol (TAP) were studied in infected guinea pigs after the administration of thiamphenicol glycinate N-acetylcysteinate (TGA). Animals received a single dose of TGA (15 mg/kg, subcutaneously) immediately after intra-tracheal infection with Haemophilus influenzae (about 10(7) CFU/animal). Serum and lung concentrations of TAP were determined at 0, 1, 3, 6, 12 and 24 h after drug administration by means of HPLC. TAP serum levels were elevated at 1 h and remained detectable for 24 h after drug administration. Tissue lung levels were comparable to peak serum concentrations but remained higher and decreased more slowly than serum concentrations.

Genotyping in HIV drug resistance mutations: epidemiology in 145 patients.

The epidemiology of HIV-1 genomic mutations causing antiretroviral drug resistance, in 145 HIV-1 infected patients were obtained using a new sequencing technique. All patients were in a follow up treatment for at least 4 months with all drugs available in clinical practice in accordance to international guidelines. The percentage of the mutations were calculated both on the number of all participants and on the number of patients who received the drugs selecting for that specific resistance. It was possible then to evaluate patients who showed the mutation without receiving the drug. We consider this new sequencing method reliable and hopeful in clinical practice, giving the opportunity for a guided therapy for the single patient and in detecting and monitoring the antiretroviral drug resistance mutations in the pertinent geographic area following a periodic surveillance program.

Candida albicans cellular internalization: a new pathogenic factor?

The preliminary results of a study to show the possibility that Candida albicans can internalize into epithelial cells are reported. The study was performed on buccal, vaginal and HeLa cells. Buccal and vaginal cells, at a concentration of 5 x 10(4) cells/ml and HeLa monolayers were incubated for 2, 3 and 4 h with 10(5) colony forming units of a Candida albicans isolate. After incubation, non-internalised yeasts were eliminated and samples were processed for examination by Scanning Electron Microscopy. Results suggest that receptor-mediated endocytosis could be involved in the pathogenesis of recurrent oral and vaginal infections. This phenomenon could represent an interesting experimental model to testing drug interference in the development of therapeutic strategies against C. albicans infections.

Impact of cefetamet-pivoxil on intestinal microflora: in vivo study.

In our study we considered the possible interference of cefetamet-pivoxil with the intestinal microflora. We used 60 germ-free mice in which an intestinal microflora similar to the human one had been implanted. They were treated with 14.3 mg/Kg/die (standard dose) and a 28.6 mg/kg/die (daily dose) of cefetamet-pivoxil by oral route. The results obtained in vivo proved that cefetamet-pivoxil at therapeutic doses does not influence the normal intestinal microflora.

Effect of moxifloxacin on bacterial pathogenicity factors in comparison with amoxicillin, clarithromycin and ceftriaxone.

Moxifloxacin is a recent fluoroquinolone with an antibacterial spectrum encompassing both aerobic Gram-negative and Gram-positive strains, as well as anaerobic bacteria. In this study the activity of moxifloxacin against Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis, Haemophilus influenzae, Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, and effects of subinhibitory concentrations on bacterial morphology and adhesion properties were compared with those of amoxicillin, clarithromycin and ceftriaxone. The in vitro activity of moxifloxacin against Gram-positive and Gram-negative pathogens was equal to or better than that of comparators. Subinhibitory concentrations of moxifloxacin significantly affected bacterial morphology of S. pneumoniae, M. catarrhalis, H. influenzae and P. aeruginosa, leading to formation of spherical forms and filaments. Moreover, bacterial adhesion to buccal cells and fibroblasts was reduced after treatment with 1/4 and 1/8 X MIC of moxifloxacin. In conclusion, subinhibitory concentrations of moxifloxacin remarkably interfere with some bacterial pathogenic factors, thereby contributing to its antimicrobial activity.

Antimycotic activity and phagocytosis effects of econazole in combination with ibuprofen isobuthanolammonium against vaginal strains.

Vaginal infections caused by Candida spp., other yeasts and Trichomonas vaginalis are problematic mainly due to the various factors involved in development of infection and to the failure of common treatments. In this study we investigated the presence of synergistic activity of econazole and ibuprofen isobuthanolammonium against 310 different vaginal isolates, by using the microdilution broth assay to test in vitro antimicrobial activity and the effect of the two drugs on phagocytosis and intramacrophagic cellular killing of mouse peritoneal macrophages. The effect of sub-inhibitory concentrations of econazole / ibuprofen isobuthanolammonium combination on Candida albicans germ tube formation was also evaluated. The in vitro antifungal activity of econazole was notably improved by addition of ibuprofen isobuthanolammonium. Macrophage killing of C. albicans was significantly increased by the two drugs and also germ-tube formation was significantly affected. We conclude that the addition of ibuprofen isobuthanolammonium to econazole provides better in vitro antifungal activity. However, further studies are needed to elucidate the in vivo action of this formulation.

In vitro antimicrobial activity of propolis dry extract.

In this study the antibacterial and antifungal properties of propolis, a natural product of bees, have been investigated against different pathogens. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined according to NCCLS standards on 320 strains including Staphylococcus aureus, Group A beta-hemolytic streptococci, Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans. Time-kill curves were assessed for susceptible microorganisms, testing 0, 0.5, 1, 2, 4 x MIC for propolis, by counting viable bacteria after 0, 3, 6, 24 hours and viable yeasts after 0, 3, 6, 24 and 48 hours. Propolis showed good antimicrobial activity against most of the isolates, particularly S. pneumoniae, H. influenzae and M. catarrhalis, but not against Enterobacteriaceae. Time-kill curves demonstrated bacteriostatic rather than bactericidal activity of propolis, the latter being evident only at high concentrations.

Escherichia coli: effect of fosfomycin trometamol on some urovirulence factors.

The aim of our study was to evaluate the interference of fosfomycin trometanol (F.T.), at subinhibitory concentrations (1/4 and 1/8 MICs), on some urovirulence factors of Escherichia coli (12 strains). We tested fimbriae production, adhesion to uroepithelial cells, hydrophobicity, motility and hemolysin production of E. coli grown in the presence or absence of F.T. The strains tested, grown in the presence of F.T. (1/8 MIC), were less capable of adhering to uroepithelial cells, had less hemagglutination and reduced motility. This behavior was enhanced at 1/4 MIC of F.T. The hemolysin production and hydrophobicity properties present in some of our tested strains also were significantly decreased when the E. coli were grown in the presence of sub-MIC concentrations of F.T. These results suggest that F.T. may be of clinical use as treatment for acute urinary tract infection and in pyelonephritis prophylaxis.

Microbiological evaluation of commercial probiotic products available in Italy.

Scientific evidence of the prevention and therapy of some intestinal diseases is accumulating in regard to probiotic products. However, sufficient information on the use of probiotics in specific therapies is not yet available and, above all, there is no clear legislation about these products in Europe. In this study, we evaluated five different probiotic products commercially available in Italy for their qualitative and quantitative microbial content after about 12 and 22 months of storage. We also evaluated the stability of lactobacilli to 0.3% bile salts and to pH of 3.58 and 7.98. There were discrepancies between the declared content and our results found after storage for 4 of the tested products. Bile salts and basic pH did not affect the growth of the lactobacilli tested, while for 2 tested products 6 hours at acid pH produced a complete inhibition of bacterial growth. Our results suggest the need for clear legislation and adequate control of the manufacturing of probiotic products.

Effects of three different fish oil formulations on Helicobacter pylori growth and viability: in vitro study.

Helicobacter pylori infection is currently treated with antimicrobial agents in combination with antacids. Recent studies have described the in vitro bactericidal activity of fish oils and polyunsaturated fatty acids on H. pylori, and reduced rates of duodenal ulcer in people with high intake of these substances. In this study we have tested the in vitro activity of three different fish oil formulations on H. pylori strains using the Kirby Bauer method and an in vitro antibacterial test on bacteria adhered to cellular monolayers. Our results demonstrate that one of the oils is active. In this study we cannot speculate on which component of the active oil is effective and its mechanism of action, but we hypothesize that a higher concentration of icosapentaenoic acid and docosahexaenoic acid occurs in the active oil. Further in vitro and in vivo studies are needed before proposing fish oils as treatment of H. pylori infection.