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Campylobacter spp. is the most common gastrointestinal pathogen worldwide with a very low reported incidence in Italy. In November of 2013, local and national public health authorities investigated an outbreak caused by Campylobacter jejuni among children in a kindergarten in Northern Italy. A case was defined as a child who had diarrhea with a laboratory-confirmed diagnosis of C. jejuni between 11 and 30 November. Stool samples from the kindergarten kitchen staff and environmental samples from the kitchen were examined for enteric pathogens. As food leftovers were not available, the menu logbook of the refectory was reviewed to identify a possible source of the outbreak. C. jejuni strains were tested for antimicrobial susceptibility and subtyped by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). We identified 20 cases among 247 schoolchildren (attack rate = 8%), all who reported having lunch in the kindergarten. The stools from the kitchen staff as well as the environmental samples were negative for enteric pathogens. The identified outbreak strains (n = 5) were sensitive to all of the antimicrobials tested; the first four strains showed an identical PFGE profile, whereas the fifth strain showed a PFGE pattern similarity of 89%. Using MLST, all five strains were assigned to a single sequence type (ST), ST451 (clonal complex, CC21); this was the first identification of ST and the third reported outbreak of C. jejuni in Italy. Molecular typing confirmed that most of the cases belonged to a clonal cluster supporting the hypothesis of a common source; however, the source was not identified. Due to a delayed start of the investigation, it was not possible to perform any microbiological evaluation of the food consumed.

Monophasic variant of Salmonella enterica subspecies enterica serovar Typhimurium (monophasic S. Typhimurium), with antigenic structure 1,4,[5],12:i:-, appears to be of increasing importance in Europe. In Italy, monophasic S. Typhimurium represented the third most frequent Salmonella serovar isolated from human cases between 2004 and 2008. From June 2013 to October 2014, a total of 206 human cases of salmonellosis were identified in Abruzzo region (Central Italy). Obtained clinical isolates characterised showed S. Typhimurium 1,4,[5],12:i:- with sole resistance to nalidixic acid, which had never been observed in Italy in monophasic S. Typhimurium, neither in humans nor in animals or foods. Epidemiological, microbiological and environmental investigations were conducted to try to identify the outbreak source. Cases were interviewed using a standardised questionnaire and microbiological tests were performed on human as well as environmental samples, including samples from fruit and vegetables, pigs, and surface water. Investigation results did not identify the final vehicle of human infection, although a link between the human cases and the contamination of irrigation water channels was suggested.

Salmonella enterica subsp. enterica serovar 4,[5],12:i:- DT193 is recognized as an emerging monophasic variant of Salmonella Typhimurium in many European countries. Resistance to ampicillin, streptomycin, sulphonamides, and tetracycline (R-type ASSuT) is described as one of the most common profiles of resistance within this clone. Recently, strains presenting such features were isolated from two unrelated outbreaks in Italy. Strains were characterized by pulsed-field gel electrophoresis (PFGE), performed with XbaI, BlnI, and SpeI, and multiple-locus variable-number tandem repeat analysis (MLVA). XbaI-PFGE showed strains related to the two outbreaks as indistinguishable. Conversely, both BlnI-PFGE and MLVA characterized the strains related the two outbreaks as different. XbaI-PFGE identified two profiles, differing by one band, within strains isolated from one of the two outbreaks. Also BlnI-PFGE and MLVA generated different profiles among the strains related to that outbreak. Combining the PFGE profiles obtained by XbaI and BlnI and comparing them with the MLVA profiles, the two methods grouped the same isolates based on identity. Moreover, genomic deletions of the genes included in the operon fljAB, the flanking iroB gene, and the closely located STM2757 gene were investigated. For all strains, the same profile of deletion characterized by the absence of fljA, fljB, and hin genes and the presence of STM2757 and iroB genes was identified. This profile of deletion represents a mixture between two profiles of Salmonella 4,[5],12:i:- described as the "Spanish" and the "U.S." clones. This study demonstrated that although strains of Salmonella 4,[5],12:i:- DT193 ASSuT are highly clonal, minor differences between strains may be seen during the same outbreak by using in parallel PFGE with different restriction enzymes, MLVA, and the analysis of molecular markers related to the operon fljAB. The combination of these different molecular approaches was essential to clarify the epidemiological relationship among the strains.

Salmonella enterica serovar Napoli is an emerging serovar in Italy, France, and Switzerland, but little is known about its pathogenicity to humans. A collection of 112 strains of Salmonella Napoli isolated in Italy from human cases, foods of animal origin, and the environment have been characterized by the detection of a set of virulence genes, pulsed-field gel electrophoresis (PFGE), and antibiotic susceptibility. All the strains examined were susceptible to all the antimicrobials tested. The Salmonella pathogenicity islands genes ssaQ, mgtC spi_4D, and sopB were present from 75.0% to 100% of the tested strains. Only one human and four environmental strains showed the avrA gene. The phage-related sopE1 gene was present in 93% of the strains, whereas sodC1 and gipA genes were only in four and two environmental strains, respectively. The bcfC fimbrial gene was present in all the animal/food strains, in the 71.4% of environmental strains, and in 46.8% of the human strains, respectively. Overall, we observed 10 distinct virulence profiles (VP), but VP1-2-3 included 99 out of 112 strains. PFGE showed that 103 out of 111 isolates were grouped in four major clusters and three minor clusters, whereas two strains were totally unrelated. The most represented PFGE clusters mainly correlated with the virulotypes are VP1, VP2, and VP3. Salmonella Napoli shows an array of virulence genes similar to other serovars considered of public health importance and confirming its capability to cause infection in human. Concerning possible source of infection or reservoirs, the results did not point out any, but our hypothesis is that the environment can act as the main reservoir for Salmonella Napoli, and from there it can spill over to animals and humans. Further studies are needed to increase the knowledge on the ecology of Salmonella Napoli serovar and on the main risk factors for human infection.

A qnrB19 gene variant, carried by an IncL/M-like plasmid, was detected in a multidrug Salmonella enterica serovar Typhimurium human strain with reduced susceptibility to ciprofloxacin. The genetic environment around the gene was fully sequenced (20 kb). A large gene cluster, containing the aph, qnrB19, and blaSHV-12-like resistance genes, is inserted inside a Tn3 transposon.

Salmonella enterica serovar Typhimurium (STM) represents the prevalent cause of foodborne gastroenteritis in Italy with the majority of isolates exhibiting multidrug resistance. A resistant pattern that includes ampicillin (A), streptomycin (S), sulfonamide (Su), and tetracycline (T) (ASSuT) but lacks resistance to chloramphenicol (C) has recently emerged in Italy among strains of STM and of its monophasic variant, S. enterica subspecies enterica serovar S. 4,[5],12:i:-. With the aim to evaluate their clonal relationships, 553 strains of STM and S. 4,[5],12:i:- with the ASSuT and ACSSuT resistance patterns isolated in Italy from human infections between 2003 and 2006 were characterized by pulsed-field gel electrophoresis (PFGE) according to the PulseNet-Europe protocol and nomenclature. Among both the STM and S. 4,[5],12:i:- ASSuT strains, the predominant PFGE profile was STYMXB.0079 (53.2-73.0% of strains, respectively), while the STM ACSSuT strains belonged to the STYMXB.0061 (37.2% of strains) and STYMXB.0067 (29.9% of strains). Bionumerics cluster analysis of the nonunique PFGE profiles showed that more than 90% of ASSuT and ACSSuT-resistant strains were included in two distinct clusters with a genetic homology of 73% each other, suggesting that the ASSuT-resistant strains belong to a same clonal lineage different from that of the ACSSuT strains. Phage typing showed that 23% of the ASSuT STM strains were not typeable and 22.3% were U302. The same phage types were observed among the ASSuT strains of S. 4,[5],12:i:-. A different figure was observed for the ACSSuT strains: the STM isolates mostly belonged to DT104 (70.2%), while none of the S. 4,[5],12:i:- strains belonged to this phage type. This study indicates that the tetra-resistant ASSuT strains of STM and S. 4,[5],12:i:-, increasingly isolated in Italy, belong to a same clonal lineage and that the S. 4,[5],12:i:- strains circulating in our country mainly derive from this STM clonal lineage.

In this study 45 epidemic and sporadic isolates of Acinetobacter baumannii were investigated by antimicrobial resistance, integron identifications and genotyping. Isolates were genotyped by random amplified polymorphism (RAPD) DNA and pulsed-field gel electrophoresis (PFGE). Four different RAPD patterns were observed among the isolates of our collection, further discerned in six PFGE types. Two prevalent genotypes were identified, one corresponding to a carbapenem resistant epidemic clone, causing an outbreak at the intensive care unit of a hospital of Rome. Two class 1 integrons, carrying different gene cassette arrays, were identified among the two prevalent genotypes. Nucleotide analysis of the integron-variable regions revealed the presence of the aacA4, orfO, bla(OXA-20), and aacC1, orfX, orfX', aadA1 gene cassette arrays, respectively. All the carbapenem resistant strains analyzed in this study carried the bla (OXA-58) gene located on plasmids.

We investigated an outbreak of Acinetobacter baumannii in the intensive care unit (ICU) of a hospital in Rome, Italy. The outbreak involved 14 patients whose isolates were most frequently recovered from bronchoalveolar lavage. All isolates were multidrug-resistant and showed diminished susceptibility or resistance to carbapenems. A. baumannii strains with a similar antibiotic susceptibility pattern were isolated from the environment. Pulsed-field gel electrophoresis identified a single clone from both the patients' and environmental isolates. Because of the lack of a single source of infection, the eradication of the epidemic required a broad approach, including contact isolation and cohorting, aggressive environmental disinfection, and close monitoring of the ward staff's performance. Infected patients were successfully treated with combined therapy. Although considered of low virulence, A. baumannii can be particularly aggressive and difficult to treat in ICU patients.