A new emerging oral infection: Raoultella planticola in a boy with haematological malignancy.

BACKGROUND: Oral mucositis is a common complication in pediatric cancer patients, affecting up to 80% of children. Due to neutropenia and disruption of the mucosal barrier, chemotherapy-induced oral mucositis is often complicated by super-infections. CASE REPORT: A 16-years old male with stage 3 Burkitt's lymphoma developed chemotherapy induced oral mucositis grade 3 (according to WHO scale). Ulcers were quickly growing (reaching a maximum diameter of 3 cm) and became greyish in colour, resulting in dysphagia and pain. A swab of the lesions was taken and microbiological tests were performed. The sample grew for Raoultella planticola, an encapsulated Gram-negative bacterium whose full pathogenic potential still needs to be defined. TREATMENT: The patient received antibiotic combination therapy with Amikacin and Ceftazidime for 8 days. Complete healing of the lesions and resolution of the symptoms were reached and he completed his antineoplastic therapy without further complications. FOLLOW-UP: Twelve months after the infection, he is alive and well, with no oral complaints. CONCLUSION: This is the first report of a Raoultella planticola infection in a patient with chemotherapy induced oral mucositis. This type of infection must be added to the list of organisms to be considered when caring for these patients.

Evaluation of the expression of IFN-gamma in lymphocytes using a monoclonal antibody and flow cytometry.

A stable hybridoma cell line secreting specific antibodies against human interferon-gamma (IFN-gamma) and designated IGMB-14 has been established. It belongs to the IgG1, kappa subclass and it reacts in Western blot with the 28 kDa and 56 kDa polypeptides present in two different affinity purified IFN-gamma preparations. Peripheral blood mononuclear cells (PBMC) from a healthy individual, stimulated in vitro by PHA, were analysed for IFN-gamma production both when viable and following fixation. The presence of cytoplasmic or surface IFN-gamma was visualized by an indirect immunofluorescence assay using monoclonal antibody (MAb) IGMB-14 and a single laser FACS-III fluorescence-activated cell sorter. The staining permitted the detection of newly synthesized cytoplasmic IFN-gamma molecules in lymphocytes at day 1 after PHA stimulation and surface IFN-gamma at day 2. IFN-gamma was expressed on almost all the CD4+ lymphocytes as shown by a double staining technique. The specificity of the reaction was confirmed by Western blots and abolishing IFN-gamma staining by pretreatment of MAb IGMB-14 with IFN-gamma. The presence of surface IFN-gamma was also visualized on freshly isolated PBMC from two patients suffering from measles and AIDS but not on PBMC from a healthy individual. The experiments showed that this immunofluorescent method is useful for the detection, enumeration, and phenotypic characterization of IFN-gamma-producing cells in vitro and, in addition, for evaluating the presence of PBMC expressing IFN-gamma on their surface during a viral disease.

Purification of natural human IFN-gamma antibodies.

Natural antibodies to interferon gamma (IFN-gamma) were found in patients suffering from various viral infections, but also at weak titers in healthy individuals. In the present study we describe a one-step chromatographic procedure for the purification of the anti-IFN-gamma antibodies from human Ig preparations, using a recombinant IFN-gamma-coupled Sepharose CL4B affinity column. The antibodies to IFN-gamma were eluted from the column using 3 different methods without loss of immunological activity. They were found to be Ig, mostly of the IgG1 subclass, and, in the biological assay, to be able to neutralize the de novo expression of Fc receptor sites induced by IFN-gamma on U937 cells.

Interferon-gamma is associated with the surface of the human immunodeficiency virus and binds to the gag gene product p17.

Purified HIV-1 antigen preparations produced in cell culture were found to contain interferon-gamma (IFN-gamma). Electron microscopic examination of HIV-1 released by H9 cells, a cell line found to produce IFN-gamma, showed the presence of this molecule on the surface of the virus particle. The HIV-1 protein p17 was found to bind IFN-gamma by a solid-phase radioimmunoassay. The specificity of the reaction was confirmed by Western blot analysis. This finding opens new questions about the biologic role of IFN-gamma itself and of its interaction with HIV.

Antibiotic resistances and plasmids in Staphylococcus aureus from Italian hospitals.

A total of 473 Staphylococcus aureus isolates from six Italian hospitals was examined for susceptibility to several antimicrobial agents and for plasmid content. Methicillin-resistant S. aureus (MRSA) were characterised by a plasmid of mol. wt (10(6)) 18-22 or 25 that carried the determinants for penicillinase production, resistance to cadmium ions and resistance to tetracycline. MRSA isolates usually harboured other smaller plasmids of mol. wt (10(6)) 2.8, 2.6 and 1.65 that encoded resistance to tetracycline, chloramphenicol and erythromycin, respectively, and cryptic plasmids of mol. wt (10(6)) c. 2 and 1 were found frequently. Methicillin-sensitive S. aureus (MSSA) that produced penicillinase often carried plasmids of mol. wt (10(6)) 11 or 13. No particular difference was found in plasmid patterns of strains from the various sources. Analysis of plasmids by EcoRI digestion showed that plasmids of similar mol. wt and phenotypic characteristics may have different restriction patterns, but often share one or more fragments in common.

Liquid competition radioimmunoassay for the detection and quantitation of the HIV p24.

Productive infection of permissive cell cultures by HIV has been detected by different assays of which the measurement of reverse transcriptase (RT) activity has been considered highly specific and sensitive. Here we describe the production and characterization of a mouse hybridoma cell line, MB12, secreting monoclonal antibodies to HIV p24, the major core protein, and the use of this monoclonal antibody to develop a type specific indirect liquid competitive radioimmunoassay (RIA) capable of providing earlier detection of the replicating virus than the RT assay. This assay also provides a quantitative analysis of HIV p24, which can be used to study the viral replication in permissive cell cultures. The ease of methodology and the adaptability of the competitive RIA to various assay conditions make this immunoassay suitable for the study of HIV expression in infected cell cultures.

Anti-interferon-gamma antibodies in sera from HIV infected patients.

High serum levels of antibodies to interferon-gamma (IFN-gamma) have been found in patients infected with human immunodeficiency virus (HIV). A radioimmunoassay (RIA) with a recombinant IFN-gamma protein or an affinity purified IFN-gamma preparation as antigens, was developed to detect the specific anti-IFN-gamma antibodies. Reactivity of sera to IFN-gamma was confirmed by Western blot analysis. These antibodies, however, do not seem to recognize the active site of the molecule, since they do not neutralize the antiviral IFN-gamma activity in a biological assay. These results enforce the hypothesis of the role of autoimmunization during the course of the disease.

Comparison of the in vitro antibacterial activity of teicoplanin and vancomycin against gram-positive cocci.

The antibacterial activity of teicoplanin and vancomycin against 231 clinical isolates of staphylococci and enterococci was evaluated by standardized agar dilution testing. The two antibiotics showed similar activity against staphylococci. However teicoplanin was significantly more active against enterococci. Killing curves indicated that the bactericidal activity of teicoplanin at the concentration of 2 X MIC was equal to its activity at 8 X MIC.

Rufloxacin (MF-934): in vitro and in vivo antibacterial activity.

Rufloxacin (MF-934) is a new quinolone which shows in vitro antibacterial activity against E. coli, Salmonella, Klebsiella, Proteus and Staphylococcus spp. Lower in vitro activity was observed with Pseudomonas, Serratia, Enterobacter and the streptococci group D. The antimicrobial activity of MF-934 in vitro is higher than that of nalidixic acid but lower than that of ciprofloxacin, ofloxacin, pefloxacin or norfloxacin. The protective effects of MF-934 in systemic infections in mice are lower than those of ciprofloxacin and ofloxacin. In respiratory infections in rats and in subcutaneous infections in guinea-pigs, the protective effects of MF-934 are of the same order as ciprofloxacin and ofloxacin. This is probably due to the pharmacokinetic properties of MF-934, i.e. the long half-life and tissue concentrations higher than plasma levels.

Detection of Mycoplasma genitalium from urethral swabs of human immunodeficiency virus-infected patients.

Mycoplasma have been suggested as co-factors in the pathogenesis of acquired immune deficiency syndrome (AIDS). The prevalence of urethral infection by Mycoplasma genitalium was determined by polymerase chain reaction (PCR) with urethral swabs from 35 HIV-infected patients at different stages of the disease (all of them were heterosexual men). M genitalium was detected in 2 out of 19 non-AIDS (stage A and B) patients and in a similar proportion (1 out of 14; 7.1%) of samples from healthy individuals. A dramatic increase in the frequency of M. genitalium detection was observed in samples of AIDS (stage C) patients. In fact, 9 out of 16 (56.2%) specimens tested positive by PCR. We found no association in AIDS patients between M. genitalium infection and CD4 count, Human Immunodeficiency Virus (HIV) p24 antigenemia or opportunistic infection.

[Streptococcus group B and pregnancy: the therapeutic role of topical intravaginal clindamycin]. / Streptococco di gruppo B e gravidanza: ruolo terapeutico della clindamicina topica intravaginale.

OBJECTIVE: To evaluate the clinical and therapeutic efficacy of 2% clindamycin vaginal cream in pregnant women heavily colonized with group B streptococci (GBS). STUDY DESIGN: A prospective, clinical trial in which carriers of group B streptococci were randomized to receive topical intravaginal clindamycin or oral amoxicillin. PATIENTS: We randomized 105 pregnant women: 55 received 2% clindamycin vaginal cream (100 mg/day for 7 days) and 50 oral amoxicillin (2 g/day for 7 days). INTERVENTIONS: Patients were treated during pregnancy, none of them received intrapartum chemoprophylaxis. On the other hand, all the neonates, within 24 hours from delivery, were studied from the microbiological point of view, carrying out auricolar, nasal, oropharyngeal and umbilical cultures. RELIEFS: The eradication of the microorganism was evaluated by performing a vaginal culture after 6 weeks from the beginning of antibiotic therapy. RESULTS: The eradication rate of the microorganism was significantly higher in women treated with topical clindamycin compared with the group receiving oral amoxicillin (71% versus 36%; p < 0.05). The neonatal outcome was similar in the two groups in terms of gestational age at delivery and mean birthweight. None of the neonates was admitted to the neonatal intensive care unit and no cases of neonatal sepsis were recorded. CONCLUSIONS: From our experience we can conclude that, during pregnancy, a treatment with topical intravaginal clindamycin may be useful in the eradication of GBS.

Expression of activation markers on peripheral-blood lymphocytes following oral administration of Bacillus subtilis spores.

This study was undertaken to assess the capability of Bacillus subtilis spores to modify the peripheral-blood lymphocyte (PBL) subsets or determine the de novo expression of activation markers. The data we obtained show that spores of B. subtilis are able to increase the expression of certain cell activation markers and that such activation is dose-dependent. In fact, doses of 2 x 10(9) spores did not give rise to changes in any of the parameters evaluated, while doses of 6 x 10(9) increased the HLA-DR antigen expression on T-lymphocytes. At the highest dosage used (12 x 10(9), B. subtilis spores caused the appearance of cells bearing the CD25 and CD71 activation markers. Therefore, such cell activation markers may prove useful for monitoring the activity of B. subtilis spores, and possibly of other immunomodulating agents, in the course of clinical research.

Resistance to beta-lactam antibacterial agents in hospitals.

In recent years, due to the frequent use of antimicrobial agents, strains resistant to antibiotics have been seen with increasing frequency among hospital isolates. We have compared the susceptibility to different beta-lactam drugs of Pseudomonas spp. and Staphylococcus aureus strains, isolated during a 10-yr period (1974-1984) from pathological specimens of different units of Spedali Civili of Brescia Medical School. We have also analyzed the plasmid DNA profile of representative Staphylococcus aureus strains isolated in 1984.

Expression of gamma interferon on circulating lymphocytes in viral infections.

Peripheral blood lymphocytes from a total of 111 patients and 40 healthy individuals were studied for gamma interferon (IFN-gamma) expression on their surfaces by indirect immunofluorescence assay and flow cytometry, with a new anti-IFN-gamma monoclonal antibody (IGMB-14) as a specific reagent. Of 64 patients with proven acute viral infections, 59 had a significantly higher percentage of lymphocytes expressing IFN-gamma on their membranes than healthy individuals did. On the other hand, only 3 (8.9%) of 34 patients with proven bacterial infections had an increased percentage of IFN-gamma-expressing lymphocytes. None of the eight patients with other infections and none of the five with systemic lupus erythematosus showed an increased percentage of IFN-gamma-positive lymphocytes. The percentage of IFN-gamma-expressing lymphocytes during a viral infection was found to be related to different stages of the disease. Finally, some applications of this rapid IFN-gamma assay method in viral diseases are discussed.

Natural antibodies to IFN-gamma in man and their increase during viral infection.

Natural antibodies to IFN-gamma were found in healthy individuals ranging from newborn babies to adults and, at higher levels, in patients suffering from different viral infections. During a viral infection, the titer of anti-IFN-gamma antibodies was observed to be correlated with the stage of the disease. Antibodies specific to IFN-gamma were affinity purified both from sera taken from healthy individuals and sera from viral-infected patients, by using a rIFN-gamma-coupled CNBr-activated Sepharose 4B column. The antibodies were found to be of the IgG class, and maintained their ability to bind rIFN-gamma. They were then tested for neutralizing activity and none of the IgG preparations we analyzed impaired the antiviral activity of rIFN-gamma. This finding suggests that the antigenic determinants recognized by these antibodies on the IFN-gamma molecule are located outside the site, on the IFN-gamma molecule, responsible for its antiviral activity.