Anna Giammanco

The seroepidemiology of Bordetella pertussis infection in Western Europe

High titres of pertussis toxin (PT) antibody have been shown to be predictive of recent infection with Bordetella pertussis. The seroprevalence of standardized anti-PT antibody was determined in six Western European countries between 1994 and 1998 and related to historical surveillance and vaccine programme data. Standardized anti-PT titres were calculated for a series of whole-cell and acellular pertussis vaccine trials. For the serological surveys, high-titre sera (> 125 units/ml) were distributed throughout all age groups in both high- (> 90%) and low-coverage (< 90%) countries. High-titre sera were more likely in infants in countries using high-titre-producing vaccines in their primary programme (Italy, 11.5%; Western Germany, 13.3%; France, 4.3%; Eastern Germany, 4.0%) compared to other countries (The Netherlands, 0.5%; Finland, 0%). Recent infection was significantly more likely in adolescents (10-19 years old) and adults in high-coverage countries (Finland, The Netherlands, France, East Germany), whereas infection was more likely in children (3-9 years old) than adolescents in low-coverage (< 90%; Italy, West Germany, United Kingdom) countries. The impact and role of programmatic changes introduced after these surveys aimed at protecting infants from severe disease by accelerating the primary schedule or vaccinating older children and adolescents with booster doses can be evaluated with this approach.

Antibody responses and persistence in the two years after immunization with two acellular vaccines and one whole-cell vaccine against pertussis

OBJECTIVE To evaluate the persistence of specific antibodies induced by primary immunization with three doses of two three-component acellular vaccines against pertussis with an observed efficacy of 84%, and one whole-cell vaccine with an observed efficacy of 36%. STUDY DESIGN Serum samples were collected from a subsample of 1572 children from the Italian double-blind, placebo-controlled, randomized trial of vaccines used in 15,601 children at three time points: before administration of the first dose of vaccine, and 1 month and approximately 15 months after administration of the third dose. Further evaluation included pooled cross-sectional analysis of serum specimens associated with episodes of cough (which were not laboratory confirmed as pertussis infection) occurring among the entire population enrolled in the trial. RESULTS With both acellular vaccines there was a fast and steep decrease in geometric mean antibody titers to pertussis toxin, filamentous hemagglutinin, and pertactin after vaccination. Mean titers were close to the limit of detection 15 months after primary immunization. The immunogenicity of the whole-cell study vaccine was poor 1 month after the third dose, and no antibody was detected in nearly all children 15 months after whole-cell vaccination. CONCLUSIONS Although the study acellular pertussis vaccines induced a strong primary specific antibody response in almost all recipients, the duration of the response was limited. Sustained high-level production of antibody to the antigens tested does not account for the observed efficacy of acellular pertussis vaccines.

Enteropathogens associated with childhood diarrhea in Italy

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, Crypto-sporidium 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.

European Sero-Epidemiology Network: standardisation of the assay results for pertussis

A standardisation process was developed in order to compare and harmonize serological results of pertussis toxin (PT) antibody measurements performed by laboratories using different technical procedures for detection. This involved the development of a common panel, of sera by a designed reference centre, the distribution of the panel to each participating laboratory for testing with their routine methods, the comparison of the obtained results to those of the reference centre, and the calculation of standardisation equations by regressing the quantitative results against those of the reference centre. As a cut-off indicative of protection against pertussis has not yet been defined, a particular emphasis was laid upon achieving standardisation of high titre results that would allow epidemiological evaluations based on the estimation of the incidence of recent infections rather than on the traditional approach of determining the population immunity profile. A generally good agreement was achieved between the participating laboratories, all using ELISA procedures very similar in many crucial aspects, and standardisation equations were produced useful to enable inter-country comparison during the next stages of the European Sero-Epidemiology Network (ESEN) project concerning the serological surveillance of immunity to pertussis in Europe.

Persistence of protection through 33 months of age provided by immunization in infancy with two three-component acellular pertussis vaccines

A large, randomized, placebo-controlled clinical trial in Italy on two three-component pertussis vaccines, given as DTaP in infancy, one manufactured by SmithKline and Beecham (SB) and one by Chiron Biocine (CB), found each vaccine to be 84% efficacious through the average age of 24 months. The cohort of children enrolled in the trial was followed with unmodified case ascertainment procedures for nine additional calendar months, during which partial unblinding occurred, for the unvaccinated randomized group. For the DTaP groups, the specific vaccine assignment remained double-blinded throughout the entire additional observation period. Pertussis was defined as paroxysmal cough lasting at least 21 days and confirmed by culture or serology. In the additional 9 months the observed absolute efficacy was 78% (95% CI, 62-87%) for SB DTaP vaccine and 89% (95% CI, 79-94%) for CB DTaP. The relative risk of developing pertussis in SB DTaP recipients compared to CB DTaP vaccinees was 1.99 (95% CI, 1.13-3.51). By combining observations from the initial and additional follow-up periods, the overall observed vaccine efficacy through an average age of 33 months of SB DTaP was 80% and of CB DTaP, 85%.

LOW PREVALENCE OF ANTI-HCV ANTIBODY AMONG ITALIAN CHILDREN

SummaryThe seroprevalence of anti-HCV antibody was studied among 2,749 children and teenagers (1,438 males and 1,311 females) living in Italy. Anti-HCV antibody testing was positive by both EIA and RIBA in ten (0.36%) subjects. The positivity rate increased with age, ranging from 0 among children less than 6 years of age to 0.8% among those aged 17–19 years x2 linear regression=0.038). Anti-HCV prevalence ranged from 0.2% in northeastern regions and in Apulia to 0.6% in Sicily and Sardinia (p>0.005), and no difference was seen between males (0.35%, C.I. 95%: 0.04–0.66) and females (0.38%, C.I. 95%:0.04–0.66) (Fishers exact test=0.565). From these data it appears that in Italy HCV infection is an uncommon event during childhood.ZusammenfassungBei 2.749 Kindern und Jugendlichen (1.438 Jungen und 1.311 Mädchen), die in Italien leben, wurde eine Studie zur Seroprävalenz der anti-HCV Antikörper durchgeführt. Bei zehn der Getesteten (0,36%) fand sich mit EIA und RIBA ein positiver Befund. Die Rate an positiven Fällen nahm mit dem Alter zu von 0 bei Kindern unter 6 Jahren auf 0,8% bei den 17–19jährigen (Chi2 lineare Regression=0,038). In den nordöstlichen Regionen and Apulien lag die anti-HCV Seroprävalenz bei 0,2%, in Sizilien und Sardinien bei 0,6% (p>0,005). Zwischen Mädchen und Jungen fand sich kein Unterschied (0,35%, 95% CI: 0,04–0,66 bei Jungen und 0,38%, 95% CI: 0,04–0,66; Fishers exakter Test 0,565). Aus diesen Daten läßt sich ableiten, daß die HCV-Infektion in der Kindheit in Italien ein seltenes Ereignis ist.

Baseline sero-epidemiology of hepatitis B virus infection in children and teenagers in Italy. A survey before mass hepatitis B vaccination

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)

An Update of the Evolving Epidemic of blaKPC Carrying Klebsiella pneumoniae in Sicily, Italy, 2014: Emergence of Multiple Non-ST258 Clones

Background In Italy, Klebsiella pneumoniae carbapenemase producing K. pneumoniae (KPC-Kp) strains are highly endemic and KPC producing CC258 is reported as the widely predominating clone. In Palermo, Italy, previous reports have confirmed this pattern. However, recent preliminary findings suggest that an epidemiological change is likely ongoing towards a polyclonal KPC-Kp spread. Here we present the results of molecular typing of 94 carbapenem non susceptible K. pneumoniae isolates detected during 2014 in the three different hospitals in Palermo, Italy. Methods and Results Ninety-four consecutive, non replicate carbapenem non susceptible isolates were identified in the three largest acute general hospitals in Palermo, Italy, in the six-month period March-August 2014. They were characterized by PCR for β-lactam, aminoglycoside and plasmid mediated fluoroquinolone resistance genetic determinants. The mgrB gene of the colistin resistant isolates was amplified and sequenced. Clonality was assessed by pulsed field gel electrophoresis and multilocus sequence typing. Eight non-CC258 sequence types (STs) were identified accounting for 60% of isolates. In particular, ST307 and ST273 accounted for 29% and 18% of isolates. CC258 isolates were more frequently susceptible to gentamicin and non-CC258 isolates to amikacin. Colistin non susceptibility was found in 42% of isolates. Modifications of mgrB were found in 32 isolates. Conclusions Concurrent clonal expansion of some STs and lateral transmission of genetic resistance determinants are likely producing a thorough change of the KPC-Kp epidemiology in Palermo, Italy. In our setting mgrB inactivation proved to substantially contribute to colistin resistance. Our findings suggest the need to continuously monitor the KPC-Kp epidemiology and to assess by a nationwide survey the possible shifting towards a polyclonal epidemic.

Detection of Bacterial and Yeast Species with the Bactec 9120 Automated System with Routine Use of Aerobic, Anaerobic, and Fungal Media

ABSTRACT During the period 2006 and 2007, all blood cultures required by four units at high infective risk and most of those required by other units of the University Hospital of Palermo, Palermo, Italy were performed using a Bactec 9120 automated blood culture system with a complete set of Plus Aerobic/F, Plus Anaerobic/F, and Mycosis IC/F bottles. The aim of the study was to enable the authors to gain firsthand experience of the culture potentialities of the three different media, to obtain information regarding the overall and specific recovery of bacteria and yeasts from blood cultures in the hospital, and to reach a decision as to whether and when to utilize anaerobic and fungal bottles. Although very few bloodstream infections (1.8%) were associated with obligate anaerobes, the traditional routine use of anaerobic bottles was confirmed because of their usefulness, not only in the detection of anaerobes, but also in that of gram-positive cocci and fermentative gram-negative bacilli. In this study, Mycosis IC/F bottles detected 77.4% of all the yeast isolates, 87.0% of yeasts belonging to the species Candida albicans, and 45.7% of nonfermentative gram-negative bacilli resistant to chloramphenicol and tobramycin. In order to improve the diagnosis of fungemia in high-risk patients, the additional routine use of fungal bottles was suggested when, as occurred in the intensive-care unit and in the hematology unit of the University Hospital of Palermo, high percentages of bloodstream infections are associated with yeasts, and/or antibiotic-resistant bacteria and/or multiple bacterial isolates capable of inhibiting yeast growth in aerobic bottles.

Identification of picobirnavirus from faeces of Italian children suffering from acute diarrhea

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.