1,720,977 research outputs found
Epidemiological characterization and phylogenetic analysis of the emerging Salmonella enterica serovar Napoli: the first cause of invasive nontyphoidal salmonellosis in Lombardy, northern Italy
No full textBackground: Salmonella enterica serovar Napoli is a nontyphoidal serotype that is currently emerging in Europe, mainly affecting Switzerland, France and Italy. In the latter, S. Napoli incidence has
increased by 28.2% during the period 2000-2011, most cases occurring in Lombardy region. Furthermore, a recently large outbreak occurred in Milan, Italy, associated to elevated rates of
hospitalization and bacteraemia, has evidenced that S. Napoli infections may become invasive. By considering the elevated invasive rate observed for that recent outbreak and the knowledge gaps, we
aimed to investigate the role of S. Napoli in invasive salmonellosis in Lombardy during the period 2010-2014, and infer the phylogeny of this emerging serotype. Material/methods: Data of human salmonellosis cases in Lombardy during the period 2010-2014 (10,858 records) were obtained from IT-ENTER-NET, a network of diagnostic laboratories. Comparative genomics analysis based on sequence data for 93 core genome loci, as described by den Bakker et al., was performed to define phylogenetic relationships of 14 Salmonella enterica subsp. enterica serotypes, including S. Napoli outbreak strain, and one S. enterica subsp. arizonae strain. Results: S. Napoli incidence in Lombardy continued to increase during the period 2010-2014. Moreover, this serotype was the first cause of invasive nontyphoidal salmonellosis during 2010-2014 (35 invasive cases out of 691, invasive rate of 5.1%). Phylogenetic analysis revealed that S. Napoli belongs to the Typhi subclade of clade A, and the most related serotype was found to be Paratyphi A. Additionally, S. Napoli genome carries the invasive determinant gene cdtB and the pathogenicity island SPI-18. Conclusions: S. Napoli is an emerging public health concern in Italy. Nevertheless, the role of nontyphoidal serotypes in invasive disease is yet poorly studied. A combination of SPI-18 island and cdtB gene was previously reported only in S. Typhi, S. Paratyphi A and clade B serotypes, all of them associated to elevated rates of invasive disease. Thus, to the best of our knowledge, this is the first time that a clade A nontyphoidal serotype presents the same virulence-genes pattern of S. Typhi and S. Paratyphi A. Our work suggests that S. Napoli potential virulence deserves attention and highlights a need to discuss its classification in nontyphoidal group
Antimicrobial resistance of Listeria monocytogenes strains isolated from humans in Northern Italy
No full textBackground: Listeria monocytogenes rarely develops acquired resistance to antibiotics. However, some studies have recently reported an increased rate of resistance to one or several clinically relevant antibiotics in environmental isolates and less frequently in clinical strains. This probably remains a marginal phenomenon for clinical strains, although only a limited number of studies have focused on the evaluation of antimicrobial resistance in Listeria.
The objective of this study was to investigate the antimicrobial susceptibility of L. monocytogenes strains isolated from humans in Northern Italy.
Materials: A total of 61 clinical strains of L. monocytogenes identified in Lombardy region during the years 2012-2013 were studied. All strains were tested with the disk diffusion method as recommended by European Committee on Antimicrobial Susceptibility Testing (EUCAST). Molecular subtyping were performed by Pulsed-Field Gel Electropheresis (PFGE) according to the PulseNet protocol with AscI and ApaI enzymes to detect clusters and support epidemiological investigations.
Results: All 61 human L. monocytogenes strains were found to be susceptible to penicillin G (1 unit), ampicillin (2 μg) and meropenem (10 μg), while resistance to trimethoprim-sulfamethoxazole (1.25-23.75 μg) and erythromycin (15 μg) were found in 11 (18%) and 6 (9.8%) clinical strains according to EUCAST breakpoint. Twenty-one PFGE pulsotypes and seven clusters with homology over 80% were recognized, but no correlation was observed between L. monocytogenes molecular type and resistance to trimethoprim-sulfamethoxazole and/or erythromycin. Finally, only one of the seven clusters shows a PFGE homology of 100% and a complete overlap with the drug susceptibility pattern.
Conclusion: Our findings reveal an increased rate of resistance compared to the previous study in the same geographical area (Madeo et al., 2014). Despite the low prevalence of antimicrobial resistance presently observed in human strains of L. monocytogenes isolated in Northern Italy, the emergence of resistant strains worldwide underlines the need for a continuous surveillance for this pathogen. Moreover, new susceptibility data for human strains of L. monocytogenes can provide useful information for epidemiological and public health purposes
Salmonellosi non tifoidee: l’anomala distribuzione dei sierotipi in Lombardia
No full textIntroduzione. Tra i sierotipi agenti di salmonellosi non tifoidea (SNT) in Europa, S. Enteritidis rappresenta il primo in ordine di frequenza (39.5%, report EFSA/ECDC 2014), mentre in Italia i dati Enter-Net evidenziano che il sierotipo prevalente è S. Typhimurium (29.4%), seguito dalla sua variante monofasica S. 4,[5],12:i:- (15.5%) e da S. Enteritidis (10.4%). Nell’ultima decade, è stato registrato un significativo aumento degli isolamenti di S. Napoli, attualmente quinto sierotipo più diffuso (4.1%) in Italia ed emergente soprattutto in Lombardia (Graziani et al., 2013), ma non incluso tra i sierotipi top-ten europei.
Metodi. La distribuzione dei sierotipi responsabili di casi di SNT in Lombardia è stata ricavata dall’analisi dei dati raccolti dal sistema di sorveglianza di laboratorio Enter-Net per il periodo 2010-2014.
Risultati. I risultati evidenziano un progressivo aumento degli isolamenti di S. Napoli, che nel 2014, su un totale di 1645 casi di SNT, si è attestata al terzo posto (8.1%), preceduta solamente da S. Typhimurium (15.9%) e da S. 4,[5],12:i:- (40.7%), mentre S. Enteritidis ha subito una drastica riduzione, occupando la quarta posizione (7.2%). La distribuzione dei casi non si è rivelata omogenea, con i più alti valori di incidenza nelle province di Varese, Como e Lecco, dove si è anche osservata una netta stagionalità, con un picco tra giugno e ottobre.
Conclusioni. Lo studio ha evidenziato interessanti differenze nella distribuzione dei sierotipi non solo rispetto al resto d’Europa e alle altre regioni italiane, ma anche all’interno della Lombardia. In particolare, sono emerse la ridotta frequenza di S. Enteritidis e la rilevanza del sierotipo Napoli, che richiede ulteriori indagini per identificare la nicchia ecologica, probabilmente associata all’ecosistema dei laghi prealpini che caratterizzano le province più interessate e che potrebbe essere all’origine della trasmissione all’uomo, sia waterborne che foodborne
Survey on foodborne-related risk perception during pregnancy
No full textOBJECTIVES. Foodborne diseases represent a significant public health problem, particularly in pregnant women. Therefore, food safety education is fundamental to minimize risks. The objective of this study was to assess pregnancy women’s awareness regarding food safety practices, foodborne pathogens and diseases, in order to improve preventive strategies.
MATERIALS AND METHODS. During an overall period of four months (July 2011 and April-June 2012), all the pregnant women attending a medical examination at the obstetrical clinic of the San Paolo hospital (Milan, Italy) were invited to respond to an anonymous and voluntary questionnaire, which consisted of fourteen multiple-choice questions designed to assess their knowledge regarding foodborne diseases and the sources they used to gather information on food safety. The associations between categorical variables were assessed using the chi-square test.
RESULTS. A total of 218 women, aged 20-47 years, completed the questionnaire. Of the respondents, 100 (45.9%) were Italian and 118 (54.1%) were foreign-born: European (18.9%), African (16.5%), Asian (13.3%) and American (5.5%). Half women (44.9%) obtained a high school diploma. Results showed an incomplete knowledge about foodborne pathogens as well as high-risk foods. Most of the interviewed women (82.6%) considered Toxoplasma gondii dangerous, while only 6.9% indicated Listeria monocytogenes as harmful. Most of the questionnaire participants (85.3%) identified raw meat a food to be avoided in pregnancy. Cured meat and seafood were identified as high-risk foods by approximately half of the respondents (56.4% and 45.4%, respectively), while less than 2% considered milk consumption as a risk factor. Overall, 54.1% of the pregnant women demonstrated an insufficient level of knowledge, with the highest percentage (86.2%) among the Africans, those with the lower education level.
CONCLUSIONS. This study revealed a clear lack of knowledge in pregnant women regarding food safety practices and foodborne diseases, especially among those with a low level of education. In particular, results pointed out a limited knowledge about listeriosis and its prevention, while toxoplasmosis-related knowledge was generally good. Therefore, information sources regarding prevention of foodborne diseases should be improved, ensuring easy access for women from all population groups, in order to prevent adverse pregnancy outcomes
Antimicrobial resistance of Shigella sonnei isolates carrying class 2 integron in Northern Italy
No full textBackground: In the last decades, several reports on Shigella sonnei epidemiology from different countries have associated the epidemic circulation of this organism to a well defined strain, characterized by some proprierties, like a resistant phenotype streptomycin, sulfonamide, trimethoprim and tetracycline, a distinct XBaI pulsotype and the presence of class 2 integron. The objective of this study was to evaluate the genetic heterogeneity of molecular profiles, drug susceptibility pattern, and carriage of class 2 integron of S. sonnei collected in northern Italy. Materials: A total of twenty-five clinical isolates of S. sonnei identified in Lombardy region during the years 2009-2012 were studied. All isolates were subtyped by Pulsed-Field Gel Electropheresis (PFGE) according to the PulseNet protocol with XBaI enzyme to detect clusters and support epidemiological investigations. Furthermore, antimicrobial susceptibility testing was performed by the disk diffusion method as recommended by the National Committee of Clinical Laboratory Standards. Finally, polymerase chain reaction (PCR) was performed with the specific primer pair -hep74 and hep51- to detect the class 2 integron. Results: Eight XbaI pulsotypes with homology over 80% were recognized among the 25 clinical isolates. Twenty-three isolates were grouped in six clusters, while the remaining two isolates showed unique pulsotypes, one of which was reported in 2001 (Mammina et al., J. Clin. Microbiol., 2005). Two different class 2 integron structures were identified. Nine (36%) isolates contained a 2.22-kbp gene cassette (dhfr1, sat, and aad) were phenotypically resistant to trimethoprim and streptomycin, also ten (40%) isolate produced a smaller cassette structure of 1.37-kbp encoding only two genes within the cassette (dhfr1 and sat) were resistant to streptomycin. Finally, no class 2 integrons were detected in the remaining six (24%) isolates. Conclusion: The finding of our studies revealed the persistence of a pulsotype isolated in Lombardy in 2001. Moreover, ten S. sonnei isolates containing defective class 2 integron (1.37-kbp) were resistant to streptomycin. It is possible that in this case the streptomycin resistance may be due to aad gene present on a plasmid
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Napoli Strain SN310, Cause of a Multischool Outbreak in Milan, Italy, in 2014
No full textWe report the draft genome sequence of Salmonella enterica subsp. enterica serovar Napoli strain SN310, isolated from a stool sample of an affected pupil during a multischool outbreak in 2014 in Milan, Italy. This represents the first reported draft genome sequence of the emerging serovar Napoli
Salmonella enterica Serotype Napoli is the first cause of invasive nontyphoidal salmonellosis in Lombardy, Italy (2010-2014), and belongs to typhi subclade
No full textSalmonella enterica serotype Napoli (S. Napoli) is currently emerging in Europe and particularly in Italy, where in 2014 it caused a large outbreak associated with elevated rates of bacteremia. However, no study has yet investigated its invasive ability and phylogenetic classification. Here, we show that between 2010 and 2014, S. Napoli was the first cause of invasive salmonellosis affecting 40 cases out of 687 (invasive index: 5.8%), which is significantly higher than the invasive index of all the other nontyphoidal serotypes (2.0%, p < 0.05). Genomic and phylogenetic analyses of an invasive isolate revealed that S. Napoli belongs to Typhi subclade in clade A, Paratyphi A being the most related serotype and carrying almost identical pattern of typhoid-associated genes. This work presents evidence of invasive capacity of S. Napoli and argues for reconsideration of its nontyphoidal category
A multischool outbreak due to salmonella enterica serovar Napoli associated with elevated rates of hospitalizations and bacteremia, Milan, Italy, 2014
No full textA multischool outbreak of salmonellosis caused by Salmonella enterica serovar Napoli was investigated in the province of Milan from October to November 2014, following an increase in school absenteeism coinciding with two positive cases. Epidemiological studies detected 47 cases in four primary schools: 46 children and 1 adult woman (51.4% males and 48.6% females, median age 8.9). From these, 14 cases (29.8%) were severe and resulted in hospitalization, including 6 children (12.8%) who developed an invasive salmonellosis. The epidemic curve revealed an abnormally long incubation period, peaking 1 week after the first confirmed case. Twenty-five available isolates were typed by pulsed-field gel electrophoresis showing an identical pattern. The isolate belongs to ST474, an ST composed exclusively of Salmonella Napoli human strains isolated in France and Italy. Antibiotic resistance analysis showed resistance to aminoglycosides, correlating with the presence of the aminoglycoside resistance gene aadA25 in its genome. Trace-back investigations strongly suggested contaminated ham as the most likely food vehicle, which was delivered by a common food center on 21 October. Nevertheless, this ingredient could not be retrospectively investigated since it was no longer available at the repository. This represents the largest Salmonella Napoli outbreak ever reported in Italy and provides a unique scenario for studying the outcome of salmonellosis caused by this emerging and potentially invasive nontyphoidal serotype
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