Giovanna Pesavento

Impact of universal vaccination programmes on the epidemiology of hepatitis B: 10 years of experience in Italy.

Ten years have elapsed since routine vaccination of infants and of 12-year-old adolescent was implemented in Italy. In this period, evidence has accumulated on the epidemiological impact of universal immunisation. Coverage is on average >90% and is >or=95% in many areas of the country. Incidence of acute hepatitis B, that was already declining before 1991, was further decreased by routine vaccination programmes. This is particularly evident in adolescents and young adults (cohorts involved by mandatory vaccination), while incidence shows little changes in older subjects according to data of the last years. Prevalence of hepatitis B virus (HBV) markers detected by sero-epidemiological studies on anonymous sera confirms both the very high coverage with hepatitis B vaccination and the virtual absence of chronic HBsAg carriers in cohorts involved by routine vaccination programmes. The system of passive surveillance on adverse events following hepatitis B vaccination supports the excellent safety record of hepatitis B vaccines. In a hyperendemic area of Southern Italy, where a pilot programme was firstly implemented, it was also possible to document the decline of the involvement of hepatitis B in chronic liver pathologies (from 48% in 1982 to 18% in 1997). If coverage rates are maintained at the present levels, elimination of HBV transmission in Italy may be envisaged in few decades.

Specific ion effects on the growth rates of Staphylococcus aureus and Pseudomonas aeruginosa

Motivated by recent advances in the physical and chemical basis of the Hofmeister effect, we measured the rate cell growth of S. aureus--a halophilic pathogenic bacterium--and of P. aeruginosa, an opportunistic pathogen, in the presence of different aqueous salt solutions at different concentrations (0.2, 0.6 and 0.9 M). Microorganism growth rates depend strongly on the kind of anion in the growth medium. In the case of S. aureus, chloride provides a favorable growth medium, while both kosmotropes (water structure makers) and chaotropes (water structure breakers) reduce the microorganism growth. In the case of P. aeruginosa, all ions affect adversely the bacterial survival. In both cases, the trends parallel the specific ion, or Hofmeister, sequences observed in a wide range of physico-chemical systems. The correspondence with specific ion effect obtained in other studies, on the activities of a DNA restriction enzyme, of horseradish peroxidase, and of Lipase A (Aspergillus niger) is particularly striking. This work provides compelling evidence for Hofmeister effects, physical chemistry in action, in these organisms.

Sequence type 101 (ST101) as the predominant carbapenem-non-susceptible Klebsiella pneumoniae clone in an acute general hospital in Italy.

-lactamase genes were detected. Bidirectional sequencing of the ull-length KPC and IMP genes was performed as described previusly [2,3]. The PCR products were independently generated twice o characterise the type of KPC and IMP variant. Sequence alignent and analysis were performed online using the BLAST program http://www.ncbi.nlm.nih.gov). DNA sequencing results identified PC-2 and IMP-18 genes. Utilising the PCR mapping approach described by Cuzon et al. 5], blaKPC-2 was found associated with transposon Tn4401b isoorm, which has been previously identified in KPC-positive P. eruginosa from Colombia [5]. The structure of the blaIMP-18 class 1 ntegron was characterised by a PCR mapping strategy of overlaping PCR fragments that covered from integrase (intl1) to qacE 1 as reviously reported [1]. The results showed the presence of a novel n707 (JN596991) class 1 integron (blaIMP-18–aadA1b–blaOXA-224) ecently reported in nine P. aeruginosa clinical isolates from Puerto ico [1]. This case clearly illustrates several important clinical factors ssociated with the acquisition of these highly resistant, nosocoial, Gram-negative organisms, including: patient age; immune tatus; other co-morbid conditions; invasive procedures (surgery, ndwelling urinary catheters, endotracheal intubation, amongst thers), previous or current use of broad-spectrum antibiotics; proonged hospitalisation; and significant crude mortality. In addition, he KPC and IMP genes are usually associated with mobile genetic lements that can efficiently disseminate to other bacteria in the ospital environment. It is therefore important to emphasise the rompt recognition and establishment of proper therapeutic and nfection control measures in order to reduce the spread of infecions caused by these highly resistant organisms.

Exploring the Anti-Burkholderia cepacia Complex Activity of Essential Oils: A Preliminary Analysis

In this work we have checked the ability of the essential oils extracted from six different medicinal plants (Eugenia caryophyllata, Origanum vulgare, Rosmarinus officinalis, Lavandula officinalis, Melaleuca alternifolia, and Thymus vulgaris) to inhibit the growth of 18 bacterial type strains belonging to the 18 known species of the Burkholderia cepacia complex (Bcc). These bacteria are opportunistic human pathogens that can cause severe infection in immunocompromised patients, especially those affected by cystic fibrosis (CF), and are often resistant to multiple antibiotics. The analysis of the aromatograms produced by the six oils revealed that, in spite of their different chemical composition, all of them were able to contrast the growth of Bcc members. However, three of them (i.e., Eugenia caryophyllata, Origanum vulgare, and Thymus vulgaris) were particularly active versus the Bcc strains, including those exhibiting a high degree or resistance to ciprofloxacin, one of the most used antibiotics to treat Bcc infections. These three oils are also active toward both environmental and clinical strains (isolated from CF patients), suggesting that they might be used in the future to fight B. cepacia complex infections.

Progress towards measles and rubella elimination in Tuscany, Italy: the role of population seroepidemiological profile

BACKGROUND As a part of the National Plan for Measles and Congenital Rubella Elimination, a catch-up campaign targeting children aged 7-14 years with Measles-Mumps-Rubella (MMR) vaccine was conducted during 2004-05 in Tuscany, Central Italy. METHODS To assess the profile of measles and rubella susceptibility, immunoglobulin G antibodies against measles (945 subjects) and rubella (1110 subjects) were detected using two commercial enzyme-linked immunosorbent assay tests in sera from a population aged 1-49 years. RESULTS Overall immunity towards measles increased in the last years, but the WHO-Euro recommended threshold of susceptibility for elimination was attained only in 2- to 4-year-olds. All fertile women up to 29 years had rates of susceptibility clearly higher than those required by WHO-Euro (5%) to eliminate congenital rubella. Despite the reduction of susceptibility among subjects targeted by the catch-up campaign, continuous efforts to increase immunization coverage are needed to eliminate measles and rubella circulation. Our results are predictive of a high chance of measles and rubella outbreaks because of the accumulation of susceptible individuals. CONCLUSION Additional catch-up vaccination strategies targeting the adult population (particularly fertile women) are strongly needed to eliminate the risk of measles and congenital rubella syndrome for future generations.

Sero-epidemiology of hepatitis B markers in the population of Tuscany, Central Italy, 20 years after the implementation of universal vaccination

Italy was one of the first industrialized countries to introduce a program of universal vaccination against hepatitis B in 1991. Twenty years later we verified the impact of universal immunisation on the epidemiology of hepatitis B infection by analyzing the prevalence of specific viral markers (anti-HBs, anti-HBc and HBsAg). The ELISA tests were performed on residual blood samples collected by 0.05% of the resident population aged 1-50 years in Tuscany (Italy). About 63% of subjects aged < 30 years were anti-HBs positive compared to about 25% in older subjects, without differences between genders. About 22% of subjects over 40 years were anti-HBc-positive compared to 5% in the younger age groups. The number of HBsAg-positive subjects was almost 10 fold higher in the unvaccinated age groups than in the cohorts involved in the universal vaccination program. The results of our study show the persisting high anti-HBs reactivity in vaccinated cohorts, while HBV markers related to natural exposure or persistent infection remain remarkably higher in older age groups. This sero-epidemiological study supports with prevalence data the downward incidence trend of acute hepatitis B highlighted by epidemiological surveillance systems, and corroborates the forecast for elimination of hepatitis B in Italy in a few decades.

Legionella contamination in hot water systems of hospitals, nursing homes, hotels, factories and spas in Tuscany-Italy

Abstract Following the report of many cases of Legionnaires’ disease associated with accommodation facilities such as hotels, spas, workplaces, hospitals and nursing homes, we verified if Legionella pneumophila and Legionella spp. were present in some of those structures in Tuscany, in order to estimate the species and serogroups in circulation. Legionella pneumophila serogroup 1 (30.9%) was the most frequently isolated species along with serogroups 3 (16.1%) and 6 (13.3%); these three serogroups are identified, in literature, as those most responsible for Legionnaires’ disease (LD). Studying all analyzed structures, we found some parts of the water system where Legionella concentration was higher than 103CFU/L, indicated, in Italy, as the maximum admitted concentration value above which a decontamination treatment is necessary when one or more cases of healthcare-acquired Legionnaires’ disease are observed. Moreover disinfection is recommended in any case when counts exceed 104CFU/L. Consequently, in order to prevent cases of Legionnaires’ disease, a continuous surveillance of the water systems of all accommodation facilities is necessary, with particular attention to hospitals and nursing homes where immunocompromised patients lodge, so as to promptly estimate the presence of the pathogen and consequently plan the most suitable intervention activities. We concluded that, in any structure, a continuous surveillance and disinfecting treatment of water systems is necessary. Moreover, after any disinfection treatment the temperature of the hot water flowing in the system must be necessarily maintained near 51°C in order to minimize the probability of recontamination from Legionella and limit the risk of LD in consumers.

Free-range and organic farming: Eggshell contamination by mesophilic bacteria and unusual pathogens

SUMMARY The high incidence of foodborne illnesses caused by the consumption of eggs in industrialized countries is the main reason we decided to determine the microbial load on the surface of eggshells from free‐range and organic farming. The objective was to compare which was better for ensuring the least possible health risk to the consumers, focusing on consumption of raw eggs by immune‐compromised people. Bacteria come from the intestine of the animal or subsequent contamination. When eggs are cracked, bacteria from the shell reach the yolk and the albumen, and grow during manipulation and preservation, causing foodborne diseases in consumers. Microorganisms such as Salmonella, Listeria monocytogenes, Campylobacter, Enterobacteriaceae (including E. coli serotype O157: H7), Staphylococcus, Enterococcus, and mesophilic aerobic bacteria, were examined. The presence of bacteria on eggshells depends on hygienic conditions of the farming and packaging industries. Hygienic measures, such as strict cleaning and disinfection of surfaces in contact with eggs in packaging industries, would be a protective factor to minimize the contamination of eggshells. The total absence of pathogens demonstrates the relevance for human consumption of eggs coming from both free‐range and organic farms, though YOPI (young, old, pregnant, or immune‐compromised) people preferably should cook eggs in which bacteria contaminating the outer surface are killed.