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Resistance to saquinavir (Ro 31-8959), an inhibitor of human immunodeficiency virus type I proteinase, was studied in peripheral blood mononuclear cell-derived proviral DNA from patients undergoing prolonged treatment. A Leu90-->Met exchange was the predominant resistance mutation in vivo; Gly48-->Val or doubly mutant virus was rarely observed. After 8-12 months of treatment with saquinavir alone (600 mg, 3 times/day) or in combination with zidovudine (200 mg, 3 times/day), approximately 45% of all patients carried provirus with mutant proteinase; the incidence was lower (22%) in patients treated with a combination of saquinavir, zidovudine, and dideoxycytidine. There was a good relationship between genotypic analysis of saquinavir resistance and data from virus assays, confirming that Leu90-->Met and Gly48-->Val are the essential exchanges in the proteinase that determine loss of sensitivity to this inhibitor. Absence of genotypic resistance correlated with a sustained decrease in plasma viral RNA. There was a positive correlation between a Met90 mutation and some residues at natural polymorphic sites (positions 10, 36, 63, and 71).

A genotypic analysis of the HIV-1 proteinase was performed on clinical specimen obtained from patients after different periods of Saquinavir (SQV) treatment. Proteinase genes of integrated proviral DNA from PBMC were isolated by PCR, cloned and individual sequences were obtained. Genotypic resistance was defined by the Gly48-->Val and Leu90-->Met exchanges. Frequencies and kinetics of resistance development will be reported for phase I/II trials V13330. V13329, O13328 and ACTG229 in patients on monotherapy or combination therapy with RT inhibitors. Data from V13330 have been analysed in more detail for correspondence of genotypic and phenotypic resistance and any correlation between resistance and changes in plasma viral RNA load. Furthermore, we will discuss the data from our extensive proteinase gene sequence collection with respect to mutational changes which would be indicative of resistance to other inhibitors of HIV-1 proteinase.

Rhodococcus equi causes a rare infection in immunocompromised hosts. We describe 24 cases of infection in patients with AIDS-related complex (ARC)/acquired immunodeficiency syndrome (AIDS). Pneumonia was always the first manifestation of R. equi infection, but extrapulmonary involvement was also observed. The main sources of bacteria were sputum, bronchial washings and blood. The strains isolated were mainly susceptible to erythromycin, vancomycin, teicoplanin, rifampicin, imipenem and aminoglycosides. Initial treatment should involve an intravenously administered antibiotic combination therapy including imipenem or vancomycin or teicoplanin, followed by orally administered maintenance combination therapy. Drug combinations should be investigated for serum bactericidal activity in vitro. Surgery does not increase survival time and should only be performed in cases that do not respond to antibiotic treatment. Presumptive risks of infection (contact with horses or farm dust, or cohabiting with people affected by R. equi infection) were present in more than 50% of patients. This finding, and the frequency of bacteria in the sputum, are not sufficient proof of transmission between humans, but do suggest the need for respiratory isolation of patients affected by R. equi pneumonia.

In order to investigate the potential susceptibility of bone marrow stromal myoid cells to human immunodeficiency virus (HIV), a myoid cell population devoid of all other cellular components of marrow environment was isolated from 3 normal adult bone marrow samples. The bone marrow myoid cells were infected with 3 different strains of HIV-1, 2 strains isolated from patients with acquired immune deficiency syndrome (AIDS) and HTLV-IIIB strain. To demonstrate successful infection and HIV production, culture supernatants, harvested weekly until 2 months post-infection, were tested for the presence of p24 antigen and infectious virus. Myoid cell monolayers obtained from the 3 different bone marrow samples were shown to be susceptible to infection. In particular, infection led to the presence of p24 antigen and of infectious virus in culture supernatants up to day 49 post-infection. After day 49, it was not possible to demonstrate the presence of infectious virus in culture supernatants and HIV-DNA polymerase chain reaction (PCR) failed to show viral genome in any of the cultures assayed. Our results demonstrate the susceptibility of myoid stromal cells to HIV infection and may provide an in vitro model for studying the effects of HIV infection in disregulation of the haemopoietic function of bone marrow environment.

The usefulness of traditional methods of HIV plasma titration has been limited by poor detection capacity in the asymptomatic phase of HIV disease. We analyzed plasma samples from asymptomatic seropositive or early symptomatic patients, comparing the classic plasma culture method with the following techniques: phorbol 12-myristate 13-acetate treatment of target cells, centrifugal inoculation of the virus, heat treatment of cultures, addition of monocyte/macrophages to cultures, and polyethylene glycol (PEG) treatment of the plasma. Only PEG treatment significantly increased the percentage of HIV isolation. The increase of HIV isolation after PEG treatment is more evident in patients with higher CD4+ cell counts and those without detectable levels of p24 antigen. In the p24-negative samples, HIV was isolated in 17 of 24 (71%) with PEG treatment versus nine of 24 (37%) with the classic method (p < 0.01). A number of discordant samples were found using the classic and PEG methods. Combining the positive results obtained with either technique, we obtained an overall HIV detection rate of 76%. The increased sensitivity of the combination of PEG and classic methods may allow a wider use of plasma viremia as part of the virological evaluation of anti-HIV drug efficacy in asymptomatic patients.

The antibacterial activity of trospectomycin, clindamycin, metronidazole, imipenem, cefoxitin, and piperacillin was tested against 72 Bacteroides spp. strains isolated from the vagina of women with vaginitis by determining the minimal inhibitory concentration using the agar dilution method. Trospectomycin shows a good activity which is comparable to that of imipenem and metronidazole. Its expanded spectrum of activity makes trospectomycin suitable for the use in single-drug therapy of pelvic infections in women.

A semimicromethod was established for isolating human immunodeficiency virus (HIV) in plasma using 48-well plates and a pool of peripheral blood mononuclear cells (PBMC) from several donors as targets for infection, which increases the efficiency of isolation by reducing the effect of variability due to diverse donor cell susceptibility to HIV infection. The addition of H9 cells to the PBMC cultures did not affect measurable titers. Nevertheless, it potentiated strongly virus replication in terms of p24 production in the supernatant of the wells with HIV isolates, thus facilitating interpretation of the results. The titration of a virus strain of a known titre and reverse transcriptase activity in parallel provided a constant parameter of efficiency and reproducibility within each experiment, permitting comparison with results from other laboratories. The reproducibility of the method was highly significant (r = 0.97, P < 0.001); 68% of the 22 plasma samples from HIV-infected individuals tested by this method were positive. The presence of plasma HIV titer correlated well (P < 0.02) with the low count of CD4+ cells of less than 300/mm3, but not with the presence of the p24 antigen in the serum.

Seven patients with staphylococcal neurosurgical shunt infections were treated with intraventricular teicoplanin. Two infants received 5 mg/d, three patients received 20 mg/d, and two patients received 20 mg every other day. Six of these patients also received intravenous antibiotics. Three patients had infections caused by methicillin-susceptible Staphylococcus epidermidis, and one patient had an infection caused by methicillin-resistant S. epidermidis. Three patients were infected with Staphylococcus aureus (one with a methicillin-resistant strain and two with methicillin-susceptible strains). The mean duration of intraventricular therapy was 16 days. Sterilization of cerebrospinal fluid (CSF) was obtained after an average of 4.4 days. All patients were cured both clinically and microbiologically. No significant adverse effects were observed in any patients. Penetration of teicoplanin into the CSF after intravenous administration was poor. However, after intraventricular administration, high and prolonged peak and trough levels of teicoplanin were detected in the CSF. Bactericidal activity of the CSF was remarkable, exceeding the 1:8 dilution in the majority of the cases. The alternate-day schedule of intraventricular administration of teicoplanin was as effective as the once-daily regimen.

A double-blind placebo controlled trial of oral acyclovir in otherwise healthy immune competent young adults with chickenpox was conducted. One hundred males were recruited into the trial, fifty were randomised to receive acyclovir at a dose of 800 mg five times daily for 5 days and fifty to receive matching placebo. Acyclovir recipients experienced itching and required anti-pruritic therapy for a significantly shorter period of time (p less than 0.05); no significant effects of acyclovir therapy on overall rash progression were observed. In patients with a mild rash on entry the maximum daily temperature recorded was significantly lower in the acyclovir group as compared with placebo recipients on day 1 of therapy (p less than 0.01). Acyclovir was extremely well tolerated and no adverse events were reported. Studies with early oral acyclovir therapy in otherwise healthy children with chickenpox has demonstrated significant benefits, particularly in rash progression. It is postulated that the partial benefits shown in this study in adults reflect the high proportion of patients with mild disease and enrollment of the majority of patients more than 24 hours after the rash onset.

The Authors report the results obtained in 35 patients of either sex suffering from various systemic infections and treated with netilmicin. Netilmicin has been intramuscularly administered in once daily dose of 4.5 mg/kg (mean daily dose 294.3 mg) for a mean duration of 17.8 days. The clinical resolution of the infections has been achieved in 97.1% (34 patients) of the study population; only one patient showed failure. Thirty-three of the 35 baseline causative pathogens have been eradicated. The local and systemic tolerability was good. The serum pharmacokinetics showed bactericidal levels of netilmicin and no serum accumulation.

The use of teicoplanin was evaluated in a group of 33 patients, which included 18 prosthetic infections, seven with osteomyelitis, five skin and soft tissue infections, and three cases of septic arthritis. The bacterial pathogens isolated were 27 isolates of Staphylococcus aureus (methicillin sensitive 18; methicillin resistant 9), Staph. hominis (2), Staph. epidermidis (1), Staph. haemolyticus (2), Enterococcus faecalis (1), Streptococcus pyogenes (1), Peptococcus spp. (1). Eleven patients had polymicrobial infections (Gram-positive plus Gram-negative and/or anaerobic bacteria). In ten cases (nine polymicrobial infections) teicoplanin was used in combination with other antibiotics. Teicoplanin was administered intravenously 400 mg every 24 h in 26 cases, 200 mg every 24 h in six cases and 600 mg every 24 h in one case. The duration of the treatment ranged from 9 to 73 days with a mean of 27.3. Efficacy was evaluable in 30 patients, because in three patients treatment was stopped because of adverse reactions. Cure or improvement was noted in 28 patients (93%). Bacteriological cure occurred in 25 patients (83.3%).

During the period 1951-1976 the annual mortality rate due to pneumonia decreased from about 60 deaths/100.000 to about 26 deaths/100.000. By studying the pattern of mortality in relation to the age of population, it is shown that pneumonia deaths in the elder group (greater than 60 year-old) progressively diminished from 1951 (266/100.000) to 1966 (125/100.000). After this year mortality rates showed to stabilize their levels. Pneumonia mortality among people with age between 0-5 years and 5-60 years showed a progressive decline during all the period here examined. At this time elder people seem to contribute to more than 80% of mortality from pneumonia in Italy.

The single radial haemolysis technique was employed for the detection of rubella antibodies. By using this technique, as compared with the conventional haemagglutination-inhibition test on the same serum samples, it was observed that the single radial haemolysis technique supplies a reliable method for large rubella antibody screening.

The case of a young man of 20 who, after aspecific prodromic symptomatology of viral type, presented a clinical picture characterised by encephalitis and hepatitis classifiable in Reye's syndrome is reported. Bioenzymatic data and therapeutic outlook are discussed.

Antibody response of 68 healthy young-adult volunteers to A/Bangkok/1/79 (H3N2), A/Brazil/11/78 (H1N1), B/Singapore/222/79 trivalent anti-influenza virus vaccine was studied by haemagglutination inhibition and single radial haemolysis techniques. The results of this study indicate that immunogenicity of the individual components of the vaccine (10 micrograms each) varied significantly, the highest frequence of antibody response occurring for A/Brazil influenza virus strain and the lowest for B/Singapore.

Seventy-five young recruits received an intramuscular dose of anti-influenza virus vaccine containing 300 U.I. of A/Texas/1/77 (H3N2), A/URSS/90/77 (H1N1), B/Hong Kong/8/73 strains. Antibody responses were detected by HI and SRH tests: immunogenicity of the preparation was different for the individual vaccine strain in spite of the similar amount of antigenic content, and the immunity conferred by vaccine strains did not significantly extend to new influenza virus strains which prevailed in 1979/80 winter season with the exception for A/Brazil/11/78 (H1N1).

We have developed a murine monoclonal antibody reactive with a major immediate early 72,000 dalton protein of human cytomegalovirus and utilized this reagent in a rapid virus titration and microneutralization assay. Because of the early expression of this virus encoded protein, both assays could be accomplished within 16 h following virus inoculation. In addition, both assays resulted in considerable savings of reagents because the assays were carried out in 96-well microtiter plates. These assays should prove useful in the preparation and study of neutralizing antibodies directed against human cytomegalovirus.

A clinical and epidemiological assessment of 1258 hospital patients in Piedmont in 1977-1979 showed that, at present, the frequency of hepatitis A and B can be regarded as virtually the same, that males are more frequently affected, that AVH A is more frequent in early life, whereas AVH B is significantly more common later, that urban areas are more frequently stricken than rural areas, that AVH A is more common in persons living in groups, whereas AVH B is more frequent among pensioners and the unemployed (the latter being primarily drug-addicts). Patients with AVH A, and hence a minor hepatitic involvement, had shorter hospital stays, while the immune response in both types of hepatitis is characterized by a more frequent increase in gamma-globulins, coupled with arise in IgM levels.

Data on hemoagglutination inhibition (HI) tests for rubella immunity which were performed in our laboratory since 1972, are reported. The results obtained on sera from healthy young women indicate a significant decrease of incidence of sero-negatives in 1978 as compared with previous years. The incidence of high titer-positive sera and the geometric mean titer of HI antibody were significantly greater in 1973 and 1978 than in the remaining years; a greater number of case reports to Public Health Authorities occurred in Rome during these two years. The data are also discussed in relationship with vaccination program.

In the period from September 1981 to April 1982, one strain of influenza virus (A-H3N2) was isolated from 121 throat cultures obtained from patients with acute febrile respiratory disease. A sero-epidemiological survey on 520 serum samples and evaluation of excess mortality from respiratory diseases did not show significant activity of influenza viruses during the period from October 1981 to October 1982.

In this study we report about the efficacy and tolerability of ceftazidime in the treatment of 10 cases of pseudomonal meningitis (nine Pseudomonas aeruginosa and one Pseudomonas cepacia). The 10 patients had a pseudomonal infection of the central nervous system (CNS) complicating neurosurgical procedures or developed on a preexisting immunodepressing condition; four patients were of pediatric age. All isolates were sensitive to ceftazidime with MICs ranging from 0.39 to 3.12 micrograms/ml. Ceftazidime was given intravenously at the dosage of 100-150 mg/kg/day. In seven cases amikacin was associated by intralumbar or intraventricular instillation. The duration of ceftazidime treatment ranged from 9 to 49 days with a mean of 22.2. Eight cases out of ten were cured bacteriologically and clinically, while the remaining two were cured after treatment with other antibiotics. Concentrations of ceftazidime in serum and in lumbar and/or ventricular cerebrospinal fluid (CSF) were obtained in four cases; the mean concentration in lumbar CSF was 12.2 micrograms/ml and in ventricular 3.3 micrograms/ml. The study demonstrated that ceftazidime is effective in the treatment of Pseudomonal meningitis.

In the periods from July 1982 to June 1983 and July 1983 to June 1984, 31 strains of influenza virus, of which 19 A/H3N2 6 A/H1N1 and 6 type B, were isolated from 242 throat cultures obtained from patients with acute febrile respiratory disease. A seroepidemiological survey on 520 serum samples confirms significant activity of influenza viruses during the winterly period of 1983-1984. In the period July-August 1983 the evaluation of mortality from respiratory diseases presents an excess in respect of epidemic threshold probably ascribable to heat stroke.

Live attenuated influenza vaccine containing the recombinant of A/Victoria/3/75 with A/PR/8/34 virus was administered to healthy adults in a field trial aimed at evaluating protection provided by immunization. The study was designed to measure the effect of vaccination on absenteeism from respiratory disease during a natural influenza epidemic. A total of 2115 male employees of the public transport service of Rome volunteered to participate in the trial, 1050 and 1065 receiving vaccine and placebo respectively, in a randomized blind fashion. Vaccination procedure was completed by the end of December 1976. A small-sized outbreak of influenza, due to a viral strain antigenically homologous to the vaccine, occurred during the month of February 1977. Analysis of absenteeism data, classified according to medical certificate, indicated that morbidity from respiratory disease was reduced in vaccinees compared with controls during the epidemic month; the rate of increase of morbidity compared with that of the preceding month was then three times lower in vaccinees than in controls and the difference in absenteeism between the two groups greatly exceeded the ordinary fluctuation that was observed during non-epidemic periods.

Complement fixation (CF), immunofluorescence (IF) and immunoenzymatic (ELISA) tests by commercial sources were compared, for routine laboratory detection of cytomegalovirus IgG antibodies, on 120 serum samples from normal pregnant females. IF and ELISA were comparable in terms of specificity and sensitivity, but in our opinion ELISA showed some advantages with regard to need for facilities and trained personnel. CF could not detect some of low titer positive sera, so it can not be suggested where it is critical to know a previous contact with the virus, as in blood donors or transplant donors and recipients.