A. Dambrosio

High occurrence of Helicobacter pylori in raw goat, sheep and cow milk inferred by glmM gene: a risk of food-borne infection?

Helicobacter pylori is an organism widespread in humans and sometimes responsible for serious illnesses, such as gastric and duodenal ulcers, MALToma and even gastric cancer. It has been hypothesized that the infection route by H. pylori involves multiple pathways including food-borne transmission, as the microorganism has been detected from foods such as sheep and cow milk. This work reports the results of a survey conducted in order to investigate the presence of H. pylori in raw goat, sheep and cow milk produced in Southern Italy, employing a Nested Polymerase Chain Reaction (Nested-PCR) assay for the detection of the phosphoglucosamine mutase gene (glmM), as screening method followed by conventional bacteriological isolation. Out of the 400 raw milk samples examined, 139 (34.7%) resulted positive for the presence of glmM gene, but no strains were isolated. In this work H. pylori DNA has been firstly detected from 41 (25.6%) raw goat milk samples. The results deserve further investigations on the contamination source/s of the milk samples and on the major impact that it may have on consumers.

EFFECT OF REDUCING DIETARY PROTEIN LEVEL ON PERFORMANCE RESPONSES AND SOME MICROBIOLOGICAL ASPECTS OF BROILER CHICKENS UNDER SUMMER ENVIRONMENTAL CONDITIONS

This study examined the effect of different crude protein (CP) levels in the diet on growth performance of broilers as well as the total aerobic mesophilic count (TAMC) and Escherichia coli count (ECC) isolated from chicken faeces. A total 150 day-old broilers (Hubbard) were allocated to three treatments with five replicates containing 10 birds. The dietary treatments consisted of three diets with different CP levels for 42 days: high-protein (HCP, 22.5%), medium-protein (MCP, 20.5%), and low-protein (LCP, 18.5%). Body weight and feed intake were determined and the feed conversion ratio was calculated. Faecal samples were collected at 14, 21 and 42 days. Dietary CP did not affect the growth performance of broilers. Reducing CP level was effective at beneficially modulating the composition of the faecal microflora, in particular TAMC and ECC concentrations (log10 CFU g−1) were significant lower for the LCP birds. During hot temperature conditions (33°C and 70% relative humidity) a low protein diet may help to control the characteristics of the faecal microbial community without negative effects on broiler performance.

Methicillin-resistant Staphylococcus aureus (MRSA) in slaughtered pigs and abattoir workers in Italy

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen present in the hospital environment (HA-MRSA), in the community (CA-MRSA) and in livestock, including pigs (LA-MRSA). MRSA may enter the human food chain during slaughtering and may infect humans coming into direct contact with pigs or pork products. This study aimed to determine the prevalence and characteristics of MRSA isolated from pigs and workers at industrial abattoirs in southern Italy. A total of 215 pig nasal swabs were screened for the presence of MRSA using PCR. An MRSA isolate was detected from each mecA/nuc PCR-positive sample and characterized by spa-typing, Multi-Locus Sequence Typing, SCC-mec and Panton-Valentine Leukocidin (PVL), and also tested for the production of staphylococcal enterotoxins (SEs). Eighty-one MRSA isolates (37.6%) were obtained from the 215 pig nasal swabs; 37 of these isolates were further characterized, and showed 18 different spa-types and 8 different STs. The most frequently recovered STs were ST398 (CC398-t034, t011, t899, t1939 - 43.2%) followed by ST8 (CC8-t008, t064, t2953, t5270 - 24.3%) and ST1 (CC1-t127, t174, t2207 - 10.8%). Nine MRSA isolates were obtained from the 113 human swabs; the isolates showed 5 different spa-types and 5 different STs, including the novel ST2794 (t159). The most representative STs recovered were ST1 (CC1-t127) and ST398 (CC398-t034) (33.3%). None of the MRSA isolates showed the ability to produce SEs and PVL and all resulted resistant to two or more classes of antimicrobials. This study shows the great genetic diversity of MRSA strains in slaughtered pigs and in abattoir employees in Italy, and clearly demonstrates the need for improved hygiene standards to reduce the risk of occupational and food-borne infection linked to the handling/consumption of raw pork containing MRSA.

Comparison of methods for the detection of methicillin resistance in Staphylococcus aureus isolates from food products

Aims:  To compare several methods for detection of methicillin resistance in Staphylococcus aureus isolates from food.

Toxic Metals (Hg, Cd, and Pb) in Fishery Products Imported into Italy: Suitability for Human Consumption

Mercury, cadmium, and lead concentrations were determined in various fishery products (fishes, cephalopod molluscs, and crustaceans) imported into Italy from many European and non-European coastal countries. Considerable differences were found in the concentrations of these metals among the products tested. The highest mean Hg concentration was found in fishes (0.21 μg g(-1) wet weight), whereas cephalopods had the highest mean Cd concentration (0.35 μg g(-1) wet weight). Swordfish (0.80 μg g(-1) wet weight), longtail tuna (0.53 μg g(-1) wet weight), and thornback ray (0.52 μg g(-1) wet weight) had the highest concentrations of Hg, whereas maximum Cd concentrations were found in samples of common cuttlefish (0.85 μg g(-1) wet weight) and common octopus (0.64 μg g(-1) wet weight). The majority of the samples analyzed were in compliance with European Union legislation, except for a few cases. The calculated mean weekly intakes of Hg, Cd, and Pb through consumption of the fishery products tested were all below the legislated respective provisional tolerable weekly intakes. In general, the samples analyzed were considered safe to eat with regard to the metal concentrations found and the allowable intakes based on legislation. Nevertheless, the consumption of some species may be of significant importance for consumer health.

Verocytotoxin-producing Escherichia coli O26 in raw water buffalo (Bubalus bubalis) milk products in Italy.

Escherichia coli 026 is known as a verocytotoxin-producing E. coli (VTEC) organism that causes severe foodborne diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Although cattle are the most important reservoir of VTEC, only a few reports on the role of water buffalo (Bubalus bubalis) as a reservoir of VTEC and on the presence of these organisms in their milk are available. However, in Southern Italy, where water buffalo are intensively reared, an outbreak of hemolytic uremic syndrome due to E. coli 026 has recently been reported, in which the consumption of typical dairy products was considered to be a common risk factor. The aims of this work were to assess the prevalence of E. coli O26 in raw water buffalo milk, to characterize the virulence gene profiles of the isolates, and to evaluate their phenotypic antimicrobial resistance pattern. Of 160 analyzed samples, 1 (0.6%) tested positive for E. coli O26, and the isolate showed the stx1+/stx2+/eae-/hlyA+ genotypic profile. The strain showed resistance against glycopeptides, macrolides, and penicillins. The presence of VTEC organisms in raw water buffalo milk could be considered to be a potential threat to consumers; however, the strict adherence to the processes used in the preparation of the most common buffalo dairy products could strongly mitigate the foodborne risk. To our knowledge, this article reports the first isolation and characterization of E. coli O26 VTEC in raw water buffalo milk.

Typing of Escherichia coli O157 strains isolated from fresh sausage

Abstract E. coli O157 is a foodborne pathogen responsible for serious human illnesses, such as hemorrhagic colitic and hemolytic uremic syndrome. Ground beef products are among the foods that are more commonly contaminated, and the strains isolated have been frequently found to carry virulence factors of this pathotype. This paper reports the results of serotyping assays and of investigations performed to screen for virulence factors of 10 E. coli O157 strains isolated from fresh sausages purchased at retail meat outlets in various provinces of Apulia (southern Italy). The presence of verocytotoxins was assessed on VERO cells and ELISA tests. Multiplex PCR assays were performed for the eae, stx1, stx2 and hlyA genes. Six of the 10 strains examined presented the H7 antigen and all of them proved to be potentially pathogenic due to the presence of individual or multiple virulence factors.

Microbiological quality of Burrata cheese produced in Puglia region: southern Italy.

Burrata cheese is a popular typical Italian food product, produced in Puglia (an administrative region of southern Italy), and this study investigated the microbiological quality of 404 samples of this cheese. The samples were analyzed in order to quantify Escherichia coli and to detect the presence of Staphylococcus aureus, Salmonella spp., and Listeria monocytogenes. No sample exceeded the values of E. coli set by EC Regulation 1441/07 for some dairy products, while 15 (3.7%) samples tested coagulase-positive staphylococci positive, with values greater than 10(3) CFU/g. One strain of S. aureus was identified and characterized from each of these positive samples, and of these strains, 7 (46.6%) produced staphylococcal enterotoxin A, 5 (33.3%) produced staphylococcal enterotoxin C, 2 (13.3%) produced staphylococcal enterotoxin D, and 1 (6.6%) produced both staphylococcal enterotoxins A and D. All strains were mecA negative. The 15 S. aureus isolates were tested for their antimicrobial resistance patterns, and all analyzed strains showed antimicrobial resistance properties for at least one of the tested antibiotics. Testing for the other pathogens mentioned above gave negative results. The results of our study mean that the microbiological quality of Burrata cheese can be assumed to be good, although care must be taken with raw materials and good hygiene during processing in order to guarantee greater food safety.

Multiplex-touchdown PCR assay for the detection and genotyping of Helicobacter pylori from artificially contaminated sheep milk.

Helicobacter pylori (Hp) is an organism commonly present worldwide in the human population, sometimes causing serious illnesses such as duodenal and gastric ulcers, adenocarcinoma of the stomach, and low-grade B-cell mucosa-associated lymphoid tissue lymphoma of the stomach. This article describes a multiplex-touchdown PCR method for the identification and genotyping (vacA-s1/m1, sl/m2, and s2/m2-and cagA genes) of Hp directly from sheep milk artificially contaminated with Hp strains from human gastric biopsies and with Hp ATCC 43504. The strains from humans carried sl/m2 cagA+ and s2/m2 cagA allelic combinations, while the ATCC strains carried an sl/ml cagA+ allelic combination. The technique showed a sensitivity of 15 CFU/ml for species identification and of 1,500 CFU/ml for the detection of genes encoding for VacA and CagA. It has proven to be specific and rapid, and the authors suggest that it be used as a rapid screening method to ensure that sheep milk is uncontaminated with this organism.

Market survey of Vibrio spp. and other microrganisms in Italian shellfish.

A survey was conducted of Vibrio spp., Escherichia coli, fecal coliforms, and Salmonella in 644 molluscan shellfish samples marketed in the Apulia region of southern Italy. Vibrios were found in 278 samples (43%), and levels of E. coli and fecal coliforms were above the Italian legal limit in 27 and 34 samples (4 and 5%), respectively. Salmonella was not detected in any of the samples. Because the majority of the vibrio isolates were found in samples that were compliant with Italian regulations, there appears to be no relationship between the presence of microorganisms of fecal origin and the presence of vibrios potentially harmful to human health.