Prevalence, antimicrobial susceptibility and molecular typing of Methicillin-Resistant Staphylococcus aureus (MRSA) in bulk tank milk from southern Italy.

This paper assesses the prevalence of MRSA in bulk tank milk (BTM) samples from southern Italy, and the relationship between the Coagulase Positive Staphylococci count (CPS) and MRSA prevalence. Of 486 BTM samples tested, 12 samples (2.5%) resulted positive for the presence of MRSA. Great genetic diversity was found among the isolates: ST1/t127 and t174/IVa, ST5/t688/V, ST8/t unknown/IVa/V, ST45/t015/IVa, ST71/t524/V, ST88/t786/Iva, ST398/t011 and t899/IVa/V and ST2781/t1730/V. All isolates were pvl-negative and icaA positive. The majority of strains (58%) carried the ses (sec, seh, seg, seo, sem and sen) genes. All tested strains resulted susceptible to amikacin, cephalotin, cloramphenicol, gentamycin, trimethoprim - sulfamethoxazole, tobramycin and vancomycin, and variably resistant to ampicillin, oxacillin and tetracycline. No statistical association between the CPS count and MRSA detection was found in the MRSA-positive samples. Although some of the spa-types and STs detected in our survey are known to cause human infections, raw milk from Italian herds in the considered area is not a common source of MRSA. Nonetheless, it is necessary to assess the risk of foodborne infection and the risk related to the handling of milk.

Genetic variability of the PRNP gene in goat breeds from Northern and Southern Italy.

AIMS: To determine the variability of the prion protein gene (PRNP) in goats from Northern and Southern Italy. METHODS AND RESULTS: Genomic DNA isolated from goat blood was polymerase chain reaction (PCR)-amplified for the coding region of the PRNP gene and then sequenced. In total, 13 polymorphic sites were identified: G37V, T110P, G127S, M137I, I142M, I142T, H143R, R154H, P168Q, T194P, R211Q, Q222K and S240P (substitutions I142T and T194P are novel) giving rise to 14 haplotypes. Clear frequency differences between Northern and Southern breeds were found and confirmed by genetic distance analysis. CONCLUSIONS: Differences in allele distribution were found between Northern and Southern goats, in particular regarding the M142 and K222 alleles, possibly associated to scrapie resistance; philogeographical analysis supported the idea that Northern and Southern breeds may be considered as separate clusters. SIGNIFICANCE AND IMPACT OF THE STUDY: In Italy only limited studies have been carried out on caprine PRNP genotype distribution; this study is important to fill this lack of information. Moreover the finding of significant differences among allele distributions in Northern and Southern goats, especially if involved in modulating resistance/susceptibility, need to be carefully considered for the feasibility of selection plans for resistance to scrapie.

Low prevalence of Listeria monocytogenes in foods from Italy.

Listeria monocytogenes is an important foodborne pathogen that causes gastrointestinal disorders, and, especially in immunocompromised people, serious extraintestinal diseases, such as septicemia and meningitis, as well as abortion in pregnant women. Many foods, from both plant and animal origin, have been involved in listeriosis outbreaks. This article reports the results of a 12-year survey (1993 through 2004) on the presence of L. monocytogenes in several kinds of food marketed in Italy. Of 5,788 analyzed samples, 121 (2.1%) were contaminated with L. monocytogenes. The highest prevalence was found in smoked salmon (10.6%) and in poultry meat samples (8.5%) and the lowest in red meat (0.3%). L. monocytogenes was not found in 154 samples of fresh seafood products. Fifty-two isolates were also serotyped by the agglutination method. The most common serotypes detected in the 52 strains tested were 1/2a (36.5%), followed by 1/2c (32.8%), 1/2b (13.5%), 4b (11.5%), 3a (3.8%), and 3b (1.9%). The results of the present study showed low levels of L. monocytogenes in the analyzed samples. A total of 61.5% of the 52 L. monocytogenes strains analyzed belonged to serotypes 1/2a, 1/2b, and 4b, namely the serovars that are most commonly involved in extraintestinal human listeriosis outbreaks. In the ready-to-eat samples, these three serotypes were 40.0% (1/2a), 17.1% (1/2b), and 14.3% (4b). This finding highlights the need to implement strict hygienic measures during the production, distribution, and sale of foods to reduce the risk of foodborne listeriosis in humans to an acceptable level.

Occurrence, characterization and antimicrobial resistance of enterotoxigenic Staphylococcus aureus isolated from meat and dairy products.

Staphylococcus aureus is considered to be one of the leading causes of food-borne illnesses. Milk, dairy products and meats are often contaminated with enterotoxigenic strains of this bacterium. Foodstuff contamination may occur directly from infected food-producing animals or may result from poor hygiene during production processes, or the retail and storage of foods, since humans may carry the microorganism. The number of S. aureus strains that exhibits antimicrobial-resistance properties has increased, together with the potential risk of transmitting the same properties to the human microflora via foods or inducing infections hard to be treated. This paper reports the results of a 3-year survey (2003-2005) on the occurrence of S. aureus in meat and dairy products. Of 1634 samples examined, 209 (12.8%) were contaminated with S. aureus. A total of 125 enterotoxigenic S. aureus strains were biotyped and their antimicrobial resistance pattern tested. Most of the isolated strains produced SED (33.6%), followed by SEA (18.4%), SEC (15.2%), SEB (6.4%) and belonged mainly to the Human ecovar (50.4%), followed by Ovine (23.2%), Non-Host-Specific (17.6%), Bovine (7.2%) and Poultry-like (1.6%) ecovars. Finally, the 68.8% analysed strains showed antimicrobial resistance properties at least at one of antibiotics tested. Human biotype showed antimicrobial resistance at more than one antibiotic than the other biotypes (p<0.05). The results provided evidence that the presence of enterotoxigenic and antimicrobial resistant strains of S. aureus has become remarkably widespread in foods. This calls for better control of sources of food contamination and of the spread of antimicrobial-resistance organisms.

Comparative study of anti-Hypoderma antibody kinetics in sera, single and bulk milk samples of naturally infested cattle.

The investigation was carried out in Basilicata region (Southern Italy) from October 1997 to June 1998. Fifteen dairy cows bred in semiconfined conditions on a farm with a history of hypodermosis were sampled once a month for sera and milk; bulk milk from these animals was also collected monthly from the farm's tanker. Samples were tested for anti-Hypoderma spp. antibodies (Abs) with an ELISA technique and clinical parasitological examination was carried out monthly from January to July on all the animals in order to detect grubs. Blood and single and bulk milk samples yielded similar antibody kinetics and patterns in accordance with results obtained in previous immunological surveys in Italy. All animals were warbled in the spring time. November-January was confirmed to be the most suitable period for seroepidemiological survey for weather conditions in Southern Italy. The ELISA test proved once again to be very useful because it is simple to perform and cost effective. Either blood or milk samples may be used for epidemiological surveys; bulk milk may be very useful for the preliminary detection of hypodermosis on farms or in areas where there is no data available on the diffusion of the disease.

Goat warble fly infestation by Przhevalskiana silenus (Diptera: Oestridae): immunoepidemiologic survey in the Basilicata region (southern Italy).

The demonstration of serological cross-reactivity between the Hypoderma lineatum antigen and anti-Przhevalskiana silenus antibodies led us to prepare an immunological test (ELISA) for an early diagnosis of goat warble fly infestation. Using the Hypodermosis ELISA-Kit (Vétoquinol Diagnostic, France) produced for the immunodiagnosis of bovine hypodermosis, an epidemiological assay was carried out in Basilicata region where goat breeding is very common and no data are reported with regards to the distribution of goat warble fly infestation. Out of a total of 1,100 flocks and 41,200 goats, 105 randomly extracted flocks proved to be infected and 262 sera out of 1,316 were positive; goat warble fly infestation proved to be present in Basilicata with values similar to those recorded in the surrounding regions (Apulia and Calabria). Statistical evaluation showed highly significant differences between the number of infected flocks in the mountainous areas and hills and those of the mountainous areas and the plain, but no differences between hills and plains. The higher number of positive sera and antibody titres in November-December confirmed that these months are the optimal period for sampling sera in order to perform an early diagnosis. The ELISA test was confirmed to be an easy and economic tool especially when sera sampled within a brucellosis eradication program are used.

Epidemiological research on trichinellosis in Apulia and Basilicata (southern Italy).

Trichinellosis is a zoonotic infection and has a worldwide distribution. In Italy numerous sporadic cases and outbreaks of human trichinellosis have been reported. The authors report an epidemiological survey of trichinellosis in Apulia and Basilicata, two regions of southern Italy, where two outbreaks of human trichinellosi (about one hundred cases) have recently occurred, due to ingestion of wild boar meat (sausages). Serological and/or parasitological research was carried out in the trichinellosis patients, in uninfected people (control group), and in wild and synantropic animals. The incidence of infection found in various animal species (sylvatic trichinellosis) in these two regions is high and can represent a serious health risk.