Biomedical subjects
Publications and source records attributed to A Giammanco.
Polyacrylamide gel electrophoresis of nucleic acid extracted from stool samples of diarrhoeic children revealed in 3 out of 690 (0.43%) specimens two electrophoretic bands with a migration pattern characteristic of picobirnavirus ds-RNA. In none of the 92 control children were similar bands detected. No other potential enteric pathogens were found in the patients with picobirnavirus infection.
A cytotoxin inducing vacuolation in HEp-2 cells was detected in 19 (3.1%) of 618 stool specimens from children with diarrhea but in none of 135 from control children. Common enteric pathogens were found in only two (10.5%) of the 19 cytotoxin-positive stool specimens. The vacuoles induced by stool filtrates resembled those induced by the vacuolating toxin (VacA) of Helicobacter pylori. The vacuolating toxin was heat-labile and protease-sensitive, and it had an apparent molecular weight of > 100,000 but was not neutralized by an antiserum to H. pylori VacA. Although proper prospective case-control studies are needed to definitely assess the etiologic association between the new vacuolating cytotoxin and diarrhea, the present study suggests that microorganisms of the gastrointestinal tract produce a Helicobacter-like vacuolating toxin and may be responsible for cases of childhood diarrhea whose etiology is currently considered unknown.
BACKGROUND: Infectious diarrheal diseases remain an important cause of childhood morbidity in industrialized countries. The knowledge of the etiology and epidemiology of childhood diarrhea in a given area is needed to plan any measure designed to prevent or ameliorate diarrheal illness and to develop practice guidelines for the most appropriate stool examination procedures. METHODS: We evaluated 618 children with diarrhea and 135 controls prospectively for viral, bacterial and parasitic enteric pathogens. Diarrheagenic Escherichia coli was identified by gene probes specific to different virulence factors. Stool filtrates were examined for the presence of free bacterial toxins by a cell culture cytotoxicity assay. Clinical and epidemiologic data were recorded and analyzed in relation to microbiologic findings. RESULTS: Enteropathogens were identified in 59% of children with diarrhea and in 10.4% of asymptomatic controls. The agents mainly associated with disease were rotavirus (23.6%), Salmonella (19.2%) and Campylobacter (7.9%). Rotavirus was significantly more frequent among children observed as inpatients whereas Campylobacter was significantly more common in outpatients. Infections with diarrheagenic E. coli, Shigella flexneri, yersinia enterocolitica, Cryptosporidium and Giardia were observed in a limited number of patients. The clinical presentation of children was not sufficiently characteristic to permit presumptive diagnosis of a specific pathogen. conversely the presence of blood and/or leukocytes in stools had a high positive predictive value for Salmonella or Campylobacter infection. CONCLUSION: The results of this study will be useful for planning strategies to prevent and control diarrheal diseases in our country.
Fifty-five Escherichia coli strains belonging to enteropathogenic E. coli (EPEC) serogroups were examined for phenotypic and genetic factors associated with virulence. The strains were isolated in Italy from children with diarrhea and identified as EPEC by clinical laboratories using commercially available antisera. O:H serotyping showed that 35 strains (27 of O26, O111, and O128 serogroups) belonged to 11 serotypes considered to be classical EPEC O:H serotypes. The other 20 isolates were classified as 15 nonclassical EPEC O:H serotypes. All the potential EPEC virulence factors associated with bacterial adhesion (localized adherence, fluorescentactin staining test positivity, presence of the attaching and effacing [eaeA] gene), the production of verotoxin, and the positivity with the enterohemorrhagic E. coli probe were significantly more frequent among isolates belonging to classical than nonclassical serotypes. Strains displaying an aggregative adhesion and hybridizing with the enteroaggregative DNA probe were found in serogroups O86, O111, and O126. Verotoxin-producing isolates belonged to serogroups O26, O111, and O128. Only one of the isolates hybridized with the EPEC adherence factor (EAF) probe, but 33 strains gave positive results with the eae probe, confirming that the former is more suitable in epidemiological studies in European countries. These results indicate that up to 75% of strains identified as EPEC by commercial antisera may possess potential virulence properties and/or belong to classical EPEC O:H serotypes and suggest that O grouping is still a useful diagnostic tool for presumptive identification of diarrheagenic E. coli in clinical laboratories.
In 1989, the prevalence of antibody to cytomegalovirus (CMV) was determined by the ELISA method in serum samples from 198 apparently healthy children 4-14 years old in Kumba City (Cameroon). Children were randomly recruited from six primary schools located in different districts of the city. The overall prevalence was 94.0%, increasing from 88.5% in 4-6 years old to 98% in subjects 11-14 years old. A slight male predominance was observed (96.2% versus 92.4%), which was not statistically significant. Family size and father's occupation were not associated with anti-CMV prevalence. These findings demonstrate a virtually total exposure to CMV infection by late childhood in Cameroon. However, the undesirable consequences of congenitally acquired CMV infection are rare, because nearly 100% of the women are seropositive by the time they reach childbearing age.
In 1989, the prevalence of IgG antibodies to pertussis toxin (PT) in a sample of 367 unvaccinated apparently healthy children 5-14 years old was estimated by ELISA in Kumba City (Cameroon). Children were recruited using a systematic random sampling from six primary schools located in different districts of the city. The sample was representative of the various socioeconomic classes. The overall prevalence was 75%; it increased from 62% in 5 year old children to 81% in children 12-14 years old (P less than 0.01). IgG antibody prevalence was positively related to the family size. Children belonging to households of nine or more members had a 2.2-fold risk (C.I. 95 per cent = 1.1-4.6) of previous exposure to B. pertussis infection. No association was found with the father's occupation (O.R. = 1). These findings demonstrate a great impact of pertussis infection in Cameroon, with a nearly total exposure by late childhood.
During the period May 1987 to November 1989, the prevalence of hepatitis B virus (HBV) markers was determined by ELISA in serum samples of 7405 (55% male, 45% female) apparently healthy persons 3-19 years of age in Italy. Earlier studies of adults there had shown an intermediate degree of HBV endemicity (hepatitis B surface antigen carrier rate greater than 2%). Persons were selected by systematic cluster sampling in five different geographical areas of Italy. The overall prevalence of hepatitis B surface antigen (HBsAg) was 0.6%. The overall prevalence of at least one marker of HBV was 2.8%; it increased from 1.7% among children 3-5 years of age to 4.5% in teenagers 17-19 years of age (P less than 0.001). The prevalence of any HBV marker was higher in southern then in northern areas (3.5% vs. 1.8%, P less than 0.001). A significant association was found with sociodemographic features. Persons whose fathers had less than 6 years of schooling had a 2.3-fold risk (C.I. 95% = 1.5-3.4) while those belonging to a household of six or more under one roof had a 1.7-fold risk (C.I. 95% = 1.2-2.4) of previous exposure to HBV infection. These findings indicate that, today in Italy, exposure to HBV infection at a young age is very low and suggest a shift towards a low degree of endemicity following improvements in socio-economic conditions, decreased family size and increasing use of disposable syringes during recent years.(ABSTRACT TRUNCATED AT 250 WORDS)
In Italy, immunization with diphtheria toxoid has been compulsory for all newborns since 1939. The last two clinical cases of diphtheria were reported in 1987. During the period 1987-1989, immunity against diphtheria was assessed by neutralization test in a random sample of 1740 healthy subjects 3-19 years old, from five geographical areas of Italy. Of the total population, 76.5% showed antibody levels considered to be protective (greater than or equal to 0.1 IU ml-1), 17.2% had a relative degree of protection (0.01-0.09 IU ml-1), and 6.3% lacked immunity (less than 0.01 IU ml-1). The percentage of unprotected subjects increased from 6.1% in the age group of 3-5 years to 11.4% in the age group of 18-19 years (p less than 0.01). A smaller proportion of males (5.3%) than of females (7.2%) was unprotected, but this difference was not statistically significant. Subjects residing in the south and the islands were more likely to be unprotected than those residing in the north (7.4 versus 4.1%, p less than 0.01). No association was found between lack of protective antibodies and family size (odds ratio 1.35, confidence interval 95% = 0.77-2.36). However, paternal education of less than 12 years was associated with a higher prevalence of non-responders. In order to maintain a high degree of immunity in the adult population, a routine adult booster dose of diphtheria toxoid is advisable.
Between 1987 and 1989, the prevalence of antibody to cytomegalovirus (CMV) was determined, by the ELISA method, in serum samples from 1494 apparently healthy subjects, 3-18 years old. Subjects were selected by a systematic cluster sampling from five geographical areas in Italy. The overall prevalence of antibody was 64.2%, increasing from 54.4% in 4-6-year-olds to 73.3% in subjects 17-18 years old (P less than 0.01). Prevalence of antibody was significantly higher in females (P less than 0.05) and in subjects residing in the South of Italy (P less than 0.01). A significant association was found with sociodemographic factors. Subjects belonging to a household with six or more persons had a 1.5-fold risk (C.I. 95% = 1.11-2.04) and subjects whose fathers had less than 6 years of schooling had a 1.4-fold risk (C.I. 95% = 1.1-1.87) of previous exposure to CMV infection. The high prevalence (74.4%) of young women who are naturally immune when entering childbearing years does not guarantee that there will be a low risk of fetal infection.
Between 1987 and 1989, the prevalence of antibodies to Toxoplasma gondii was determined by ELISA in serum samples from 1,494 apparently healthy subjects, 3-18 years old. Subjects were selected by a systematic cluster sampling from five geographical areas in Italy. The overall prevalence of antibodies was 17.9%, increasing from 4.7% in 4-6 year olds to 28.4% in 17-18 year olds (P less than 0.01). A slight predominance was observed among males (18.2% vs. 17.5% in females), as well as among subjects residing in Southern Italy and the Islands (21.9% vs. 19.2% in subjects residing in the North), but neither difference was statistically significant. Toxoplasma infection was associated with sociodemographic factors. Subjects belonging to a household with six or more persons had a 1.8-fold risk (C.I. 95% = 1.3-2.6) and subjects whose fathers had less than six years of schooling had a 2.7-fold rosk (C.I. 95% = 1.8-3.9) of previous exposure to toxoplasma infection. Considering the large proportion (70%) of young women entering childbearing age without toxoplasma antibodies, it appears that the risk of congenital toxoplasmosis will not be negligible in Italy in forthcoming years.
In 1988 in Palermo, Italy, the prevalence of antibodies to hepatitis A virus (anti-HAV) in a sample of 490 children 6-13 years old was 10.6%; it increased from 6.3% among children 6-10 years old to 14.7% in children 11-13 years old (P less than 0.01). Compared with findings from a survey conducted in 1978 in the same area, the results of the present study show a significant (P less than 0.01) reduction in the anti-HAV prevalence in both age groups. Anti-HAV prevalence was inversely related to the father's years of education and positively related to the family size. Children of fathers with less than 6 years of schooling had a 3.2-fold risk (C.I. 95% = 1.3-8.1), and children with five or more members in their households had a 2.7-fold risk (C.I. 95% = 1.1-6.4) of previous exposure to hepatitis A virus (HAV) infection. Our findings indicate that exposure of children in Palermo to HAV is decreasing significantly, probably because of improvements in socio-economic conditions during recent years; however socio-demographic factors appear to be important determinants of infection.
A comparative assay for epidemiological evaluation of three different Acinetobacter typing procedures, i.e. biotyping, phage-typing, and the analysis of the bacterial envelope protein profiles, was carried out using sixty-four multiresistant Acinetobacter strains isolated from clinical specimens. The antibiotic susceptibility of the strains was also considered. After geno-species identification, biotyping allowed the recognition of a relatively large and long-lasting presence, at an Intensive Therapy Unit, of two A. baumannii biotypes. Phage-typing and the analysis of the susceptibility to antibiotics allowed for the differentiation of strains belonging to different geno-species and biotypes, and in some cases also to the same biotypes. On the contrary, the analysis by polyacrylamide gel electrophoresis of the cell-envelope proteins failed to show any diversity not only within, but also between some of the biotypes of A. baumannii, the most prevalent species of the genus in the hospital environment.
Serological typing of P. aeruginosa is the most simple and reliable procedure recommended for "in-house" investigations and for studies of suspected outbreaks of infection by this microorganism. It is also a useful procedure in order to know serotype prevalence in a definite geographical area and to obtain indications about the more appropriate composition of polyvalent anti-Pseudomonas vaccines. In the present report, we describe the relatively high frequency of isolation of serogroup 12 from patients in Palermo, Italy. Serogroup 12 is very rare in north-Europe and in the USA, and, as a consequence, it is not included in some vaccine preparations. In Palermo, strains belonging to this serogroup, resistant to a large number of antibiotics, were on the contrary isolated, during more than six years, in different hospitals and from three out-patients. In a Burns Unit, they were in particular responsible for extensive and life-threatening outbreaks.
Ceftizoxime, a new, semisynthetic, beta-lactamase-resistant cephalosporin, is not metabolized in man and is excreted almost entirely as the original active compound in the urine. The efficacy and safety of ceftizoxime were assessed in 80 patients with acute and chronic urinary infections, with and without associated pathological conditions, in comparison with cefotaxime. Two dosage schedules, 1 g or 0.5 g every 12 h, i.v. or i.m. for 10 days, were adopted according to the severity of each case and to separate randomization tables for each schedule; causal agents were all sensitive to both drugs in vitro. The overall results were excellent. Safety was excellent in almost all cases. In this trial ceftizoxime proved at least as effective and well tolerated as the reference antibiotic.
Measles virus can replicate in circulating T cells, B cell and monocytes of man as well as in different human lymphoblastoid cell lines. In the present report we describe the effects on lymphoblastoid cells and on a defined population of human T lymphocytes of infection with three measles virus variants characterized by different cytopathogenicity in human and simian epithelial cell lines. The aim of the investigation was to establish some evidence that the evolution of the viral infection and the cellular damage in lymphocytes can be directly controlled by viral properties.
The Lincoln strain of bovine rotavirus, cytocidal for bovine AU-BEK cells, can establish in the same cell cultures in the presence of foetal calf serum (FCS) a persistent infection that depends on selection of highly resistant cells. In fact, after the induction of the carrier state only a small fraction of the cell population was infected. The parental and the carried viruses are not demonstrably different, the cultures are resistant to superinfection by the homologous virus, the cultures can be cured by antiviral serum in the medium and uninfected resistant cell clones can be selected. The presence of FCS was essential during induction and maintenance of persistence. Its effects appear to be exerted not on the control of virus replication in fully sensitive cells but on the proliferation and selection of the resistant cells.
During the period from May 1987 through November 1989, the prevalence of antibodies to hepatitis A virus infection (anti-HAV) was assayed by the ELISA method in the serum samples of 5,507 (54% males, 46% females) apparently healthy subjects three to 19 years old in Italy. Subjects were selected by a systematic cluster sampling in five different geographical areas of Italy. The overall prevalence of anti-HAV was 9.5%; it increased from 2.3% among children three to five-years-old to 16.3% in teenagers 17 to 19 years old (p less than 0.001). A slight preponderance of females was observed (10% versus 9.1%), but the difference was not statistically significant. The prevalence was significantly higher in Southern Italy than in Northern Italy (27.4% versus 4.8%; p less than 0.01). The prevalence of anti-HAV was inversely related to the fathers' years of schooling (O.R. 3.3; 95% C.I. = 2.5-4.2) and positively related to the family size (O.R. 2.4; 95% C.I. = 1.9-3.1). These findings indicate that, today, exposure to HAV infection at a young age in Italy is very low. However, sociodemographic factors are still important determinants in the spread of this infection.
The prevalence of IgG antibodies to Bordetella pertussis in a sample of 615 1-12-year-old unvaccinated children in Palermo was estimated by ELISA. The overall prevalence was 56%; it increased from 24% in one to three-year-old children to 67% in 11-12-year-old children (p less than 0.01). IgG antibody prevalence was not associated with the father's years of schooling (OR 1), nor with the family size (OR 1.3; C.I. 95% = 0.8-2.2). For children aged one the three years, serological results showed that the history of pertussis reported by parents in questionnaires gave high specificity (93.2%) and negative predictive value (85.4%). Our seroepidemiological study evidences a great exposure of children to B. pertussis in Palermo, with a high proportion of infections occurring after three years of age.