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.

AB0671 NO EVIDENCE OF SARS-COV-2 IN THE KNEE JOINT: A CADAVER STUDY

Background:

Despite the considerable research efforts being made to learn more about COVID-19, little is known about the presence of SARS-CoV-2 genetic material in biological fluids other than respiratory droplets, blood, and feces 1,2. In particular, little is known about the presence of SARS-CoV-2 in the joints either post mortem3 or in vivo4. To the best of our knowledge, only Lopéz-Gonzalez et al.5 have published a description of acute arthritides occurring during hospitalisation due to COVID-19, and they did not find any SARS-CoV-2 genetic material in the patients’ synovial fluid samples.

Objectives:

The aim of this post mortem study was to assess the presence of SARS-CoV-2 RNA in the knee synovial fluid, synovial tissue, and bone tissue of COVID-19 patients in order to discover whether the joint is a possible route of transmission during orthopaedic surgical procedures, and clarify the possible role of SARS-CoV-2 as a directly arthritogenic virus.

Methods:

Post mortem synovial fluid, synovial tissue and bone tissue samples were collected from the knees of five patients who died of COVID-19 in our hospital between September and October 2020, and analysed for the presence of SARS-CoV-2 using a commercial real-time polymerase chain reaction (RT-PCR) panel. Quantitative RT-PCR was used to test post mortem nasopharyngeal swabs of all of the patients.

Results:

No SARS-CoV-2 RNA was detected in any of the knee samples, despite the positivity of the throat swab.

Conclusion:

Our findings indicate that SARS-CoV-2 was not detected in knee synovial fluid, synovial membrane or bone. Therefore, our results suggest that all healthcare professionals performing surgical procedures on the joints of COVID-19 patients are exposed to a risk of contagion due to exposure to respiratory droplets, blood and body fluids, but not to direct exposure to joint- or bone-related tissues. Furthermore, given that some case reports of arthritis in COVID-19 patients 5-8 show that it is possible that COVID-19 patients display viral-mediated arthralgias and arthritis, the absence of the virus in the knee highlighted by our study suggests that it is unlikely that SARS-CoV-2 has a direct inflammatory action on the joint, but it could induce an inflammation-related reaction, manifesting as a reactive arthritis 9.

References:

[1]Cheng ZJ, Shan J. 2019 Novel coronavirus: where we are and what we know. Infection. 2020;(0123456789):1-9. doi:10.1007/s15010-020-01401-y

[2]Chen Y, Chen L, Deng Q, et al. The Presence of SARS-CoV-2 RNA in Feces of COVID-19 Patients. J Med Virol. April 2020. doi:10.1002/jmv.25825

[3]Maiese A, Manetti AC, La Russa R, et al. Autopsy findings in COVID-19-related deaths: a literature review. Forensic Sci Med Pathol. 2020. doi:10.1007/s12024-020-00310-8

[4]Baldanti F, Novazzi F, Cassaniti I, Piralla A, Di A, Bruno R. Detection of the SARS-CoV-2 in different biologic specimens from positive patients with COVID-19, in Northern Italy. Authorea. 2020. doi:10.22541/au.159724509.93056098

[5]López-González M-C, Peral-Garrido ML, Calabuig I, et al. Case series of acute arthritis during COVID-19 admission. Ann Rheum Dis. 2020;0(0):annrheumdis-2020-217914. doi:10.1136/annrheumdis-2020-217914

[6]Parisi S, Borrelli R, Bianchi S, Fusaro E. Viral arthritis and COVID-19. Lancet Rheumatol. 2020;2(11):e655-e657. doi:10.1016/S2665-9913(20)30348-9

[7]Alivernini S, Cingolani A, Gessi M, et al. Comparative analysis of synovial inflammation after SARS-CoV-2 infection. Ann Rheum Dis. 2020;0(0):2-3. doi:10.1136/annrheumdis-2020-218315

[8]Talarico R, Stagnaro C, Ferro F, Carli L, Mosca M. Symmetric peripheral polyarthritis developed during SARS-CoV-2 infection. Lancet Rheumatol. 2020;2(9):e518-e519. doi:10.1016/S2665-9913(20)30216-2

[9]Di Carlo M, Tardella M, Salaffi F. Can SARS-CoV-2 induce reactive arthritis? Clin Exp Rheumatol. 2020;In press.

Acknowledgements:

We would like to thank the clinical staff of the Pathology Unit for their collaboration in performing the autopsies.

Disclosure of Interests:

None declared

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.

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.

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.

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.

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.

Antimicrobial activity and interference of tobramycin and chloramphenicol on bacterial adhesion to intraocular lenses

The antimicrobial activities of tobramycin and chloramphenicol were evaluated by determining minimum inhibitory and bactericidal concentrations against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, group A, group B and group G streptococci, Klebsiella spp., Stenotrophomonas maltophilia and ciprofloxacin-resistant and -susceptible Pseudomonas aeruginosa, as well as by evaluating interference on adhesion of slime producer strains of S. aureus and P. aeruginosa to intraocular lens from tobramycin and chloramphenicol pharmaceutical products by scanning electron microscopy. Chloramphenicol was more active against Gram-positive bacteria than was tobramycin, which instead showed higher activity against ciprofloxacin-susceptible P. aeruginosa. Treatment of lenses with the antimicrobial products eradicated the bacterial biofilm, which was already notably reduced after 5 min. This activity was more pronounced for chloramphenicol against S. aureus and for tobramycin against P. aeruginosa. Bacterial adhesion was also significantly reduced when lenses colonized by P. aeruginosa were treated with chloramphenicol, even if they were resistant to this drug. In conclusion, the tested drugs showed marked antibacterial activity, particularly by interfering with bacterial biofilms. The data obtained in this study suggest a specific use of chloramphenicol in topical prophylaxis aimed at avoiding bacterial contaminations. However, further specific in vivo studies are needed to confirm these data.

Comparative bactericidal activity of fluoroquinolones against clinical isolates resistant to fluoroquinolones

The bactericidal activity of levofloxacin, ciprofloxacin, moxifloxacin and norfloxacin against clinical isolates conventionally classified as resistant to fluoroquinolones were compared at their maximum concentrations in serum, urine (except moxifloxacin) and bronchial mucosa (except norfloxacin). Time killing curves against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Streptococcus pneumoniae were performed. Serum concentrations of the tested drugs were not able to produce a bactericidal effect on fluoroquinolone-resistant strains. In the urine series, levofloxacin was always bactericidal (decrease > or = 3 logs CFU/ml), while norfloxacin and ciprofloxacin were bactericidal on E. coli (both), P. mirabilis (norfloxacin) and P. aeruginosa (ciprofloxacin). In the bronchial mucosa series, S. pneumoniae was rapidly killed by levofloxacin and moxifloxacin, and K. pneumoniae by levofloxacin after 12 hours. In conclusion, the maximum levofloxacin concentrations achievable at certain body sites allowed killing even of strains defined as resistant by conventional breakpoints.

Activity of levofloxacin and ciprofloxacin against urinary pathogens

This study compares the antibacterial activities of levofloxacin and ciprofloxacin against recently isolated urinary tract pathogens, by evaluating their MICs and MBCs in accordance with NCCLS susceptibility tests, time-kill curves and interference with bacterial adhesion to uroepithelial cells. A total of 200 clinical isolates was tested, including the species Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus and Staphylococcus epidermidis. All E. coli isolates were susceptible to levofloxacin and only one was resistant to ciprofloxacin, and there were no differences between beta-lactamase-positive and -negative strains. K. pneumoniae strains resistant to ciprofloxacin were also resistant to levofloxacin. Methicillin-resistant S. aureus seemed to be less susceptible than methicillin-susceptible strains to these quinolones. S. epidermidis strains were susceptible to levofloxacin and ciprofloxacin, with the exception of two isolates. Incubation of S. aureus and E. coli with subinhibitory antimicrobial concentrations reduced their capacity to adhere to uroepithelial cells; this was statistically significant at 0.25 x MIC with respect to controls (P < 0.05). Inhibition of adhesion ranged from 36 to 43% when bacteria were incubated in the presence of 0.25 x MIC of levofloxacin and ciprofloxacin, and from 10 to 27% at 0.125 x MIC. These findings suggest that levofloxacin is an effective alternative to ciprofloxacin in the treatment of urinary tract infections and that sub-inhibitory concentrations may contribute to efficacy.

Antimicrobial activity of thiamphenicol-glycinate-acetylcysteinate and other drugs against Chlamydia pneumoniae

Chlamydia pneumoniae is responsible for respiratory tract infections of both upper and lower respiratory tract. Although this bacterium is one of the most wide-spread pathogens of man, there are limited data on the antibiotic treatment of C. pneumoniae infections. The aim of this study has been to evaluate the in vitro activity of thiamphenicol glycinate acetylcysteinate (TGA, CAS 20192-91-0) in comparison with molecules with established activity against C. pneumoniae, as well as macrolides and quinolones. The results have shown that TGA and clarithromycin (CAS 81103-11-9) are the most active drugs tested, but it is important to underline that the minimal inhibitory concentration (MIC) ranges of TGA are very much lower than the breakpoint of thlamphenicol for the respiratory pathogens. In conclusion, the good antimicrobial in vitro activity of TGA against C. pneumoniae together with its in vivo characteristics, in particular the high concentration reached in lung and the combination with the mucolytic agent N-acetylcysteine (NAC, CAS 616-91-1), can make a valid choice in the treatment of respiratory tract infections caused by C. pneumoniae. These findings need further evaluation by clinical studies.

Comparative in vitro activity of thiamphenicol-glycinate and thiamphenicol-glycinate-acetylcysteinate and other antimicrobials against respiratory pathogens

Thiamphenicol-glycinate-acetylcysteinate (TGA; CAS 20192-91-0) is widely used for the treatment of infections of varied aetiology. The aim of this study was to compare the antibacterial activity of thiamphenicol-glycinate (TG; CAS 15318-45-3), TGA, amoxicillin (CAS 61336-70-7) plus clavulanic acid (CAS 58001-44-8), azithromycin (CAS 83905-01-5) and ceftriaxone (CAS 104376-79-6). Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined against Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae according to the National Committee for Clinical Laboratory Standards (NCCLS) methods. The effects of changes in assay conditions were also examined. The activity of TG and TGA was similar to that of amoxicillin plus clavulanic acid, with the exception of methicillin resistant S. aureus. Azithromycin and ceftriaxone were characterised by a limited activity against gram-positive cocci and methicillin resistant and cefinase-positive S. aureus, respectively. TG and TGA are characterized by a wide spectrum of activity, comparable to that of recent commercialized antibiotics for treatment of respiratory tract infections.

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.

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.

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.

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.

Evaluation of the abbott LCx HIV-1 RNA quantitative, a new assay for quantitative determination of human immunodeficiency virus type 1 RNA

A new quantitative reverse transcription (RT)-PCR assay for human immunodeficiency virus type 1 (HIV-1) RNA (Abbott LCx HIV RNA Quantitative assay) has been compared with the Organon NucliSens assay on 521 retrospective samples obtained from HIV-1-positive patients monitored during highly active antiretroviral therapy, 79 of whom were assayed also by the Chiron Quantiplex 3.0 system and on characterized panels. The LCx system showed a moderate correlation (r = 0.795) and gave higher results than the NucliSens system on 245 of 327 concordant positive samples, with similar sensitivity. Correlation with Quantiplex system results was higher (r = 0.943). LCx reproducibility was very good; the procedure was simple, well controlled, and rapid (up to 48 results in 7 h). The HIV RNA quantitative assay on the LCx system is suitable for routine use.

Comparative effect of thiamphenicol glycinate, thiamphenicol glycinate N-acetylcysteinate, amoxicillin plus clavulanic acid, ceftriaxone and clarithromycin on pulmonary clearance of Haemophilus influenzae in an animal model

BACKGROUND

Thiamphenicol glycinate (TG) and its derivative thiamphenicol glycinate N-acetylcysteinate (TGA) could be a valid therapeutic option in the treatment of respiratory tract infections.

METHODS

Time-kill curves of TG and TGA and pulmonary clearance in Haemophilus influenzae infected guinea pigs were compared with those of clarithromycin, ceftriaxone and amoxicillin plus clavulanic acid.

RESULTS

The bacterial activities of the tested antibiotics were comparable. When compared to the control group, lung bacterial counts were significantly lower for the TGA group at 3 h vs. controls, while for the other treatments, significant decreases were recorded after 6 h. All drugs showed a log count of <2.0 at 24 h with respect to the control while at 48 h all groups demonstrated a log count of <2.0.

CONCLUSIONS

Although the in vitro activity of the tested drugs evaluated by time-kill curves seemed comparable, some pharmacokinetic and pharmacodynamic characteristics of TGA contribute to improving the resolution of the infective process.

Lack of in vitro and in vivo selection of bacterial resistance by roxithromycin

The in vitro and in vivo selective pressure exerted by roxithromycin on Lancefield group A beta-haemolytic streptococci (GABHS) was investigated. In vitro antimicrobial activity on fifty GABHS strains was determined by the microdilution method and by boundary concentration (BC) determination. Insorgence of resistance was evaluated by redetermining MIC and BC after exposure to 16 x MIC roxithromycin concentration. In vivo insorgence of resistance was evaluated by MIC and BC determinations on the GABHS strain recovered from infected mice peritoneum, after treatment with 20 mg/kg roxithromycin. The roxithromycin serum kinetics was established in healthy and infected mice. Neither significant changes in GABHS MIC or BC after in vitro or in vivo exposure to roxithromycin nor a difference in roxithromycin serum levels between healthy and infected mice were detected, suggesting that the roxithromycin selection of resistance in GABHS is low.

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.

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.

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.

Multicenter evaluation of the mycobacteria growth indicator tube for testing susceptibility of Mycobacterium tuberculosis to first-line drugs

In a multicenter study involving three reference centers for mycobacteria, the reliability of the Mycobacteria Growth Indicator Tube (MGIT) for rapid antimicrobial susceptibility testing (AST) of Mycobacterium tuberculosis was evaluated and compared to the radiometric method (BACTEC 460TB). Test cultures for which the results of the MGIT and BACTEC 460TB tests were discordant were checked by the conventional proportion method on solid medium. Four hundred forty-one isolates have been tested for susceptibility to isoniazid (INH), rifampin (RMP), ethambutol (EMB), and streptomycin (SM). Discrepant results were obtained for three isolates (0.7%) with INH (susceptible by MGIT, resistant by BACTEC 460TB), for four isolates (0.9%) with RMP (susceptible by MGIT, resistant by BACTEC 460TB), for six isolates (1.9%) with EMB (four susceptible by MGIT, resistant by BACTEC 460TB; two resistant by MGIT, susceptible by BACTEC 460TB), and for four isolates (0.9%) with SM (two susceptible by MGIT, resistant by BACTEC 460TB; two resistant by MGIT, susceptible by BACTEC 460TB). When cultures with discordant results were tested by the conventional proportion method, about half of the cultures yielded results similar to the BACTEC 460TB results, while the other half yielded results similar to the MGIT results. Turnaround times were 3 to 14 days (median, 8.8 days) for MGIT and 3 to 15 days (median, 7.8 days) for BACTEC 460TB. There was no statistically significant difference between the susceptibility testing results of the two methods (P > 0.05). These data demonstrate that the MGIT system is an accurate, nonradiometric alternative to the BACTEC 460TB method for rapid susceptibility testing of M. tuberculosis.

Immunostimulating effect of oral glutamine

Glutamine represents the principal metabolic substrate for all rapidly proliferating cells. Since part of the glutamine efficacy could be related to immunoregulating properties, we assessed the effects of orally administered glutamine on serum interleukin-2 (IL-2) levels and intestinal T-cell populations in 48 athymic (nude) mice. Twenty-four mice received a standard diet enriched by glutamine (added to drinking water at a 4% concentration), while the other 24 served as the control group and received the same diet without glutamine. In glutamine-fed animals, we observed a marked increase in IL-2 concentrations after 10 days of treatment in comparison with control group and a modest but significant increase in intestinal T-cell counts. These results suggest that oral glutamine is able to exert local and systemic immunostimulating activity that could be of relevance in the prevention of gut integrity and immune defense loss associated, for example, with trauma, surgery, and starvation.

Interference on Helicobacter pylori growth and adhesion by omeprazole and other drugs

Helicobacter pylori is the causative agent of gastritis and a co-agent in other gastroduodenal diseases. Gastroduodenal ulcer and MALT-lymphoma in particular, regress when patients are administered antimicrobial agents to eradicate infection. Sometimes eradication is not definitive and is difficult to check. The aim of our study was to test the antimicrobial activity of omeprazole on H. pylori in comparison with ampicillin and other anti-H2 drugs (ranitidine and famotidine), and to evaluate their interference with bacterial adhesion of H. pylori. We also compared results of the agar dilution antibacterial sensitivity test on H. pylori to those obtained using a bacteria adherence to cell monolayers model, to see if drug activity was different against adhered bacteria. We evaluated omeprazole and ampicillin MIC90s (minimum inhibitory concentrations) against 20 H. pylori isolates by traditional agar dilution method and by exposing previously adhered bacteria to an Hep-2 monolayer to different drug concentrations. The activity against bacteria adhered to cell lines was evaluated by counting viable adhered bacteria after 1, 6, 12 hours of contact with drug. Interference with adherence to Hep-2 cells was also tested. Omeprazole and ampicillin MICs were comparable to other findings (omeprazole MIC90 was 12.5 microg/ml and ampicillin MIC90 was 0.016 microg/ml), while higher concentrations were necessary (4 x MIC90) against adhered bacteria. These findings suggest that MICs evaluated with traditional assays can have different predictivity than tests on adhered H. pylori.

Multicenter comparison of ESP Culture System II with BACTEC 460TB and with Lowenstein-Jensen medium for recovery of mycobacteria from different clinical specimens, including blood

The recently developed ESP Culture System II (AccuMed, Chicago, Ill.) was compared with radiometric BACTEC 460TB (Becton Dickinson, Towson, Md.) and with Lowenstein-Jensen medium for recovery of mycobacteria from over 2,500 clinical specimens both of respiratory and nonrespiratory origin, including blood. The majority of the 219 mycobacterial isolates (129) belonged to the Mycobacterium tuberculosis complex, followed by 37 isolates of the Mycobacterium avium complex (MAC) and 53 isolates of eight other mycobacterial species. Rates of recovery obtained with BACTEC, ESP, and Lowenstein-Jensen medium were 89, 79, and 64%, respectively, with such differences being statistically significant. Different media and systems appeared to behave differently when the more frequently detected organisms were considered: M. tuberculosis complex isolates grew better with BACTEC, and MAC isolates grew better with ESP. An analysis of the combinations of Lowenstein-Jensen medium with BACTEC and with ESP did not reveal significant differences in recovery rates. With regard to the times needed for the detection of positive cultures, they were significantly longer on Lowenstein-Jensen medium (average, 28 days) than with the remaining two systems, between which there was no difference (average, 18 days). We conclude, therefore, that the ESP system, when used in combination with a solid medium, performs as well as the thoroughly validated radiometric BACTEC system and offers the advantages of full automation and absence of radioisotopes.

[Lights and shadows on the molecular diagnosis of hepatitis C]

The rational application of molecular biology to clinical diagnostics must take in consideration the economic demands, as the waste of sophisticated and expensive assays is of no use for the physician prescribing the assays and burdensome for the individual or the community paying them. Sometimes it is useless to apply to the molecular biology, and the information obtainable through serology answer our demands. This brief survey of the principal means available today for Hepatitis C diagnosis and monitoring, besides summarising the principles on which the different techniques are based, wants to underline the most noteworthy aspects of the different assays--from general indication to specific application to a single case--in the attempt to improve the efficacy of the test, which may be the right one at the right moment. There are qualitative and quantitative methods for viremia determination, which not always are alternative; on the contrary they must sometimes be complementary in order to obtain a complete clinical pattern. As a matter of fact the clinician should choose according to protocol susceptibility and considering what the expected viremia could be. The risk of false negatives is very dreadful for the clinician, as that of false positives (from contamination) is threatening for the laboratory, which must carry out more work than its capabilities consent. One must not misuse these diagnostic means, but they must be used correctly in order not to transform an important service into a harmful inefficiency with unpleasant consequences both for the physician and the patient.

Serum and bone concentrations of teicoplanin and vancomycin: study in an animal model

Teicoplanin and vancomycin are antibiotics widely used in the therapy of bone and joint infections. The aim of this study was to compare bone and serum concentrations of each antibiotic in guinea pigs after administration of 50 mg/kg of teicoplanin or vancomycin by the intravenous route. Serum and bone concentrations were determined immediately before and 0.5, 1, 2, 6, 12 and 24 h after drug administration by means of high performance liquid chromatography. Teicoplanin concentrations were always higher than vancomycin levels. Area under the concentration/time curve was significantly greater for teicoplanin than for vancomycin. In bone, teicoplanin concentration increased up to 6 h, while vancomycin reached its peak after 2 h. Moreover, teicoplanin showed markedly higher levels at 6, 12 and 24 h than vancomycin. In conclusion, the ability of teicoplanin to penetrate bone in greater amount than vancomycin confirms the potential use of teicoplanin in the treatment of bone infections and in the prophylaxis of orthopedic surgery.

Algorithmic analysis of in vitro chemotherapy against Pneumocystis carinii

The development of in vitro experimental chemotherapy against P.carinii has been hindered by the lack of efficient methods for continuous cultivation of the microorganism. Various short-term systems, allowing the production of infectious forms of Pneumocystis, can be employed for in vitro experimental chemotherapy. The purpose of the present study is to describe a statistically relevant algorithmic model for the evaluation of P.carinii in short-term in vitro culture and drug screening.

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.

Impact of rufloxacin and ciprofloxacin on the intestinal microflora in a germ-free mice model

The impact of rufloxacin and ciprofloxacin on faecal microflora was investigated in an experimental germ-free mice model into which human gastrointestinal flora was introduced and stabilized. Animals received oral doses of 10, 40 or 80 mg rufloxacin/kg, 30 or 60 mg ciprofloxacin/kg once daily for 10 days, or no treatment. Microflora was studied before, during and 1 week after treatment. No significant effect ( < 2 log reduction, p > 0.05) on aerobic microflora was observed after rufloxacin as compared to controls, except for a marked decrease in enterobacteria and a slight decrease in enterococci, staphylococci and anaerobes at the highest dose. Both doses of ciprofloxacin significantly reduced enterobacteria and clostridia, while the lower dose slightly reduced peptococci, bifidobacteria and eubacteria. The depression of the intestinal ecosystem was reversible, except for enterobacteria at the higher ciprofloxacin dose. No bacterial resistance was detected after either treatment.

[Antimicrobial and sporicidal efficacy of various disinfectant solutions]

The often indiscriminate use of antimicrobial agents has led to increased bacterial resistance over the past years. This phenomenon is above all evident in nosocomial environments but also at a community level. It is therefore important that, in addition to the rational use of antibiotics, an accurate prophylaxis is performed which includes the correct use of disinfectants. This study examines the antimicrobial activity of various commercially available disinfectant solutions consisting of one or more active ingredients. An analysis of the results reveals that products consisting of an association of individual components (quaternary ammonium chloride with o-phenylphenol and/or isopropyl alcohol; chlorhexidine with benzalkonium chloride or with diazolidinylurea and isopropanol) demonstrate a greater efficacy in terms of microbicidal concentration and contact times.

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.

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.

[A microbiological evaluation of the use of roxithromycin in oral odontogenic infections]

Odontogenic infections are the primary infections caused by indigenous oral bacteria, when a factor changes their perfect equilibrium. We studied 30 samples from patients with odontogenic infections that were submitted to therapy with roxithromycin. Our results showed that 79% of aerobic and 71% of anaerobic bacteria, responsible for odontogenic infections, were sensitive to roxithromycin.

Efficacy of azithromycin compared with spiramycin in the treatment of odontogenic infections

Sixty patients with acute odontogenic infections were randomly allocated to oral treatment with azithromycin 500 mg/day once-daily for three days (n = 30) or spiramycin 3,000,000 units three-times daily for seven days (n = 30). Baseline and post-treatment oral specimens were collected from patients to test for pathogenic bacteria. Aerobic bacteria were tested using the Kirby-Bauer disc diffusion method, and anaerobic bacteria with a broth microdilution method, for their susceptibility to azithromycin and spiramycin. A greater incidence of resistance was found in the spiramycin group than in the azithromycin group. The bacteriological assessment showed that the normal balance of microflora was re-established in 67% of patients treated with azithromycin vs 53% in the group treated with spiramycin. Clinical cure was higher in the azithromycin treatment group (97%) compared with the spiramycin group (73%). These results indicate that three-day azithromycin, possibly because of its unusual pharmacokinetics, is more effective than seven-day spiramycin in the treatment of odontogenic infections.

[Roxithromycin in dental infections]

Roxithromicin is a semisynthetic macrolide antibiotic, with similar antibacterial activity to erythromycin. It is characterized by an excellent pharmacokinetic profile and a good tissue penetration. Particularly at the dose of 300 mg per day the dental tissue diffusion is extremely good, and this is important to oppose the oral cavity infections. Oral cavity infections can be either odontogenic or non odontogenic. Odontogenic infections are typically primary and are caused by commensal bacteria (oral Streptococci, Bacteroides sp., Veillonella sp. and Fusobacterium sp.). The antibacterial spectrum of roxithromycin is very large and includes many of the most frequent strains responsible for oral cavity infections. A very interesting characteristic of roxithromycin is its penetration in macrophages (uptake) that allow a more rapid inhibition of bacterial activity. To evaluate the clinical efficacy and tolerance of roxithromycin in the treatment of odontogenic infections, an open study was performed. This study evaluated both the microbiological and clinical aspects. Thirty patients (21 females and 9 males) who had not been previously treated with antibiotic or antibacterial drugs, affected by infective dysodontiasis, gingivitis and periodontal diseases, received 300 mg per day (once a day) of roxithromycin for an average period of 6 days. The symptomatology considered was: intumescence, redness, pain, lymphangitis and presence of trismus. Clinical symptomatology was assessed at the start and at the end of the treatment. The symptomatological improvement due to roxithromycin was rapid and very effective. After 6 days of therapy, the improvement was statistically significant (p < 0.01) compared to basal conditions. No adverse reactions or side-effects were complained during the study. No changement were detected in laboratory parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of Lactobacillus acidophilus and Bifidobacterium bifidum on the intestinal ecosystem of the elderly patient]

The authors have tested the therapeutic efficacy of a multibacterial combination consisting of Lactobacillus acidophilus (10(9)) and Bifidobacterium bifidum (10(9)) in elderly patients with bowel disorders. Bacteriological and histopathologic investigation showed this combination to yield excellent biologic results with restoration of duodenal bacterial flora and subsidence of clinical symptoms. The function of the muciparous glands was restored and the duodenal mucosa was normalized.

[Adhesion capacity of Enterococcus faecium (SF 68) and Enterococcus faecalis to various substrates]

The author's studied the adherence ability of Enterococcus faecium SF 68 compared to that of Enterococcus faecalis IM 11f, on various substrates: vascular catheters and cardiac valves of rabbit, immunodepressed rats and diabetic rats. The bacterial adherence test was calculated by the number of bacteria adhered for microscopic field enlarged to 2000. The data obtained by scanning electron microscope SEM (Cambridge Stereoscan 150 MK2) revealed a different adherence action of the two germs on the various substrates. All the adherence tests showed a higher and uniform adherence activity of E. faecalis compared to that of E. faecium.