Cases Of Staphylococcal Food Poisoning Research Articles

Aptamer-based photonic crystals enable ultra-trace detection of staphylococcal enterotoxin B without labels

Staphylococcal enterotoxin B (SEB) is one of the most common serotypes in staphylococcal food-poisoning cases. A rapid, sensitive, and simple method for SEB detection is crucial for public health. A photonic crystal (PC) sensing material for label-free detection of ultra-trace SEB was proposed in this study. Gold nanoparticle-doped silica microspheres were stacked to form an opal PC through self-assembly, and SEB aptamers, as the recognition element, were modified onto the PC. When the target protein of SEB came in contact with the PC sensing material, the reflection peak intensity of PCs decreased accordingly. The detection range was 1 × 10−6 to 1 ng mL−1, and the detection limit was 0.103 × 10−6 ng mL−1. Furthermore, the PC sensing material had great specificity and accuracy, which can be used for real sample monitoring. This PC sensing material achieved ultra-sensitive detection, which did not involve complicated preparation processes and reporter labelling.

Enterotoxin Production and Antibiotic Resistance Profile of Staphylococcus aureus Isolated from Meat Samples

Objective: Staphylococcal food poisoning is a major human disease that is causes by the ingestion of food contaminated by staphylococcal enterotoxins produced mainly by enterotoxigenic Staphylococcus aureus. The aim of this study was to evaluate the public health risks of the raw meat samples marketed in Giresun and Trabzon provinces regarding the contamination of Staphylococcus aureus, enterotoxin capacity of the isolates and their resistance to various antibiotics. Material and Method: A total of 30 raw bovine meat products and 38 raw chicken meat products were analyzed for micrococci/staphylococci and total staphylococci. The identification and antibiotic resistance of isolates were determined with the VITEK 2 device. Classical type enterotoxin presence in staphylococcal isolates was determined and typed using Enzyme-Linked ImmunoSorbent Assay technique. Results: The microbial loads of micrococci/staphylococci were 101 to 105 cfu/g and total staphylococci 101 to 105 cfu/g, respectively in 68 meat samples. A total of 171 staphylococci organisms were isolated from the studied 68 meat samples. Among the isolates obtained, one isolate (1.03%) detected in the raw chicken meat was found to be Staphylococcus aureus. This isolate was found to have the ability of producing enterotoxin and to produce E type enterotoxin. S.aureus isolate was resistant only to benzylpenicillin, while it was sensitive to other antibiotics. Conclusion: The results of the study indicated that antibiotic-resistant and enterotoxigenic Staphylococcus aureus poses a significant hygienic risk for consumers. Due to the posing a risk for staphylococcal food poisoning cases and threatening public health over time, extensive studies should be conducted on this subject.

Novel insights into the enterotoxigenic potential and genomic background of Staphylococcus aureus isolated from raw milk

In this study, 53 Staphylococcus (S.) aureus strains were typed by 16S–23S rDNA intergenic spacer region (ISR) typing and staphylococcal enterotoxin gene (SEg) typing for all the staphylococcal enterotoxin (se) and staphylococcal enterotoxin-like toxin (sel) genes known to date, revealing a higher discriminatory power than that of multi locus sequence typing. Six strains, one of each ISR- and SEg-type, were genome sequenced and the ability to produce some classical and new SEs when growing in milk was investigated.The manual analysis of the six genomes allowed us to confirm, correct and expand the results of common available genomic data pipelines such as VirulenceFinder. Moreover, it enabled us to (i) investigate the actual location of se and sel genes, even for genes such as selY, whose location (in the core genome) was so far unknown, (ii) find novel allelic variants of se and sel genes and pseudogenes, (iii) correctly annotate se and sel genes and pseudogenes, and (iv) discover a novel type of enterotoxin gene cluster (egc), i.e. the egc type 5 in strains 356P and 364P, while S. argenteus MSHR1132 harbored the egc type 6.Four of the six S. aureus strains produced sufficient amounts of SEA, SEC, SED and SEH in milk to cause staphylococcal food poisoning (SFP), with S. aureus 372 P being the highest producer of SED in milk found to date, producing as much as ca. 47,300 ng/mL and 49,200 ng/mL of SED, after 24 and 48 h of incubation in milk at 37 °C, respectively. S. aureus 372 P released a low amount of SER in milk, most likely because the seR gene was present as a pseudogene, putatively encoding only 51 amino acids. These findings confirm that not only the classical SEs, but also the new ones can represent a potential hazard for the consumers’ health if produced in foods in sufficient amounts. Therefore, the detection of SEs in foods, especially if involved in SFP cases, should focus not only on classical, but also on all the new SEs and SEls known to date. Where reference methods are unavailable, the presence of the relevant genes, by using the conventional and real time PCR protocols we exhaustively provided herein, and their nucleotide sequences, should be investigated.

Staphylococcal food poisoning caused by Staphylococcus argenteus harboring staphylococcal enterotoxin genes

Staphylococcal food poisoning (SFP) is caused by staphylococcal enterotoxins (SEs) preformed in food materials. SE genes are encoded on mobile genetic elements and are widely found across Staphylococcus species including S. argenteus, although most SFP cases are caused by S. aureus. S. argenteus, recently discriminated from S. aureus as a novel species, are non-pigmented staphylococci phenotypically related to S. aureus. In 2014 and 2015, two independent food poisoning cases occurred in Osaka, Japan, in which non-pigmented staphylococci were predominantly isolated. Several enterotoxin genes (seb, seg, sei, sem, sen, seo, and selu2) were found in their genome and the production of SEB was confirmed by reverse passive agglutination tests. The non-pigmented isolates from patients, food handlers, food, and cooking utensils all produced the same pulsed-field gel electrophoresis pattern. These non-pigmented isolates were coagulase-positive and biochemically identical to S. aureus. We performed further genetic analysis using nucA sequencing and multi-locus sequence typing, and identified these isolates as S. argenteus. We also found that seb was encoded on the Staphylococcus aureus pathogenicity island, while seg, sei, sem, sen, seo, and selu2 were encoded on the enterotoxin gene cluster. From these results, we concluded that the two food poisoning outbreaks were SFP cases caused by S. argenteus harboring SE genes.

Expression and characterization of single-chain variable fragment antibody against staphylococcal enterotoxin A in Escherichia coli.

The staphylococcal enterotoxins (SEs) are potent gastrointestinal exotoxins synthesized by Staphylococcus aureus, which is responsible for various diseases including septicemia, food poisoning, and toxic shock syndrome, as well as bovine mastitis. Among them, staphylococcal enterotoxin A (SEA) is one of the most commonly present serotypes in staphylococcal food poisoning cases. In this study, the stable hybridoma 3C12 producing anti-SEA monoclonal antibody was established with an equilibrium dissociation constant (KD) of 1.48 × 10(-8) mol·L(-1), its ScFv-coding genes were obtained and then the anti-SEA single chain variable fragment (ScFv) protein was expressed in Escherichia coli. Characterization of the expressed target ScFv protein was analyzed by sodium dodecyl sulfate - polyacrylamide gel electrophoresis, Western blot, and enzyme-linked immunosorbent assay. The results demonstrated that the recombinant anti-SEA ScFv protein retained a specific binding activity for SEA, and the KD value of the soluble ScFv was about 3.75 × 10(-7) mol·L(-1). The overall yield of bioactive anti-SEA ScFv in E. coli flask culture was more than 10 mg·L(-1).

Characteristics of Enterotoxin H–Producing Staphylococcus aureus Isolated from Clinical Cases and Properties of the Enterotoxin Productivity

Staphylococcal enterotoxin H (SEH) is predicted to be involved in staphylococcal food poisoning. To characterize SEH-producing Staphylococcus aureus isolates from staphylococcal food poisoning cases in Japan, we investigated the relationship between SEH production and coagulase serotype, which is an epidemiological marker, and compared the properties of SEH production with those of staphylococcal enterotoxins A (SEA) and B (SEB). SEH production was determined by a newly developed sandwich enzyme-linked immunosorbent assay. Eighty-six (59.7%) of 144 isolates from staphylococcal food poisoning cases produced SEH. Seventy-one of the SEH-producing isolates simultaneously produced SEA, SEB, or both. All SEH-producing isolates belonged to coagulase type VII, which was the predominant type, representing 99 (68.8%) of 144 isolates. The amount of SEH produced in brain heart infusion was almost the same as the amount of SEA and approximately 10-fold lower than that of SEB. SEH and SEA were produced mainly during the late exponential phase of growth, whereas SEB was produced mostly during the stationary phase. The production levels of SEH and SEA were gradually affected by decreases in water activity, but the production of SEB was greatly reduced under conditions of low water activity. These findings indicate that SEH-producing S. aureus isolates are of high prevalence in staphylococcal food poisoning cases. Given the unique epidemiological characteristic of these isolates, SEH and SEA probably are responsible for food poisoning.

Staphylococcus ENTEROTOXIGÊNICOS EM LEITE E PRODUTOS LÁCTEOS, SUAS ENTEROTOXINAS E GENES ASSOCIADOS: REVISÃO

Esta revisão de literatura teve como objetivo relatar estudos sobre a ocorrência de Staphylococcus enterotoxigênicos e suas enterotoxinas em leite e produtos lácteos, surtos e casos esporádicos de intoxicação, tipos de enterotoxinas estafilocócicas e seus genes codificadores. Dentre o gênero Staphylococcus, S. aureus é a espécie contaminante de maior prevalência em leite e queijos, principalmente queijos artesanais e está freqüentemente associada com surtos de intoxicação alimentar. As vias de contaminação de queijos podem ser o leite, o manipulador e o ambiente de processamento. Causa relevante de contaminação do leite cru é a mastite bovina, que tem S. aureus como o principal agente etiológico. Já foram identificados 18 tipos de enterotoxinas (A, B, C1, 2, 3, D, E, G, H, I, J, K, L, M, N, O, P, Q, R e U) e descritos seus respectivos genes. Relatos de ocorrência de cepas coagulase negativa com potencial enterotoxigênico em leite e produtos lácteos indicam a necessidade de reavaliação dos padrões microbiológicos estabelecidos pela legislação brasileira.

PCR detection of Staphylococcal enterotoxins (SEs) N, O, P, Q, R, U, and survey of SE types in Staphylococcus aureus isolates from food-poisoning cases in Taiwan

Staphylococcal enterotoxins (SEs) are superantigenic toxins. They are five major classical types, i.e., SEA, SEB, SEC, SED, SEE, and new SEs or SE-like superantigens, such as SEG to SEU. Only the staphylococcal superantigens (SAgs) that induce emesis following oral administration in a monkey model are designated as SEs while other related toxins are called SE-like (SEl) superantigens. To survey the enterotoxin genotypes for S. aureus strains isolated from food-poisoning cases in Taiwan, we developed PCR primers specific for SEN, SEO, SEP, SEQ, SER, and SEU genes. The complete SE sequences and their expression potential for strains positive to sen, seo, sep, seq, ser, and seu specific primers were also determined. These strains were used as reference strains. With the PCR primers specific for all SEs or SAgs, including toxic shock syndrome toxin I (TSST-1), we assayed the genotypes of 147 S. aureus strains isolated from patients associated with staphylococcal food-poisoning outbreaks occurred during 2001–2003. For these147 strains, 135 (91.8%) were found positive for one or more SE or SAg genes. For classical enterotoxin and TSST-1 types, the major one was tsst-1 (59.1%) following by sea (29.2%), seb (19.7%), sec (6.8%), and sed (2.0%). For new SE and SAg types, the major one was sei (29.9%) and sep (27.9%) followed by, sek (16.3%), seo (14.3%), seu (14.2%), sem (11.6%), sen (10.9%), seq (10.9%), seh (8.2%), sel (6.8%), and ser (5.4%) etc. This report reveals the whole SE and SAg genotypes for S. aureus strains isolated from staphylococcal food-poisoning cases in Taiwan.

Enterotoxin production by coagulase-negative staphylococci in restaurant workers from Kuwait City may be a potential cause of food poisoning.

Staphylococcus aureus and coagulase-negative staphylococci (CNS) were isolated from the hands of food handlers in 50 restaurants in Kuwait City and studied for the production of staphylococcal enterotoxins, toxic shock syndrome toxin-1, slime and resistance to antimicrobial agents. One or a combination of staphylococcal enterotoxins A, B or C were produced by 6% of the isolates, with the majority producing enterotoxin B. Toxic shock syndrome toxin-1 was detected in c. 7% of the isolates; 47% produced slime. In all, 21% of the isolates were resistant to tetracycline and 11.2% were resistant to propamidine isethionate and mercuric chloride. There was no correlation between slime and toxin production or between slime production and antibiotic resistance. The detection of enterotoxigenic CNS on food handlers suggests that such strains may contribute to food poisoning if food is contaminated by them and held in conditions that allow their growth and elaboration of the enterotoxins. It is recommended that enterotoxigenic CNS should not be ignored when investigating suspected cases of staphylococcal food poisoning.

Staphylococcal food poisoning in the United Kingdom, 1969–90

Between 1969 and 1990 strains of Staphylococcus aureus from 359 outbreaks and sporadic cases of staphylococcal food poisoning in the United Kingdom were examined in the PHLS Food Hygiene Laboratory for the production of enterotoxin. In a number of instances the incriminated foods were also examined for the presence of enterotoxin. Strains from 79% of incidents produced enterotoxin A alone or together with another enterotoxin. The level of S. aureus present in the foods ranged from no viable S. aureus detected to 1.5 x 10(10) c.f.u./g with a median of 3.0 x 10(7) c.f.u./g. Enterotoxin was detected in foods in the absence of viable S. aureus in only two outbreaks and in both cheese was the implicated food. Meat, poultry or their products were the vehicle in 75% of incidents with ham and chicken most frequently implicated. Other foods included fish and shellfish (7%) and milk and milk products (8%). Most contamination took place in the home followed by restaurants and shops. Seventy-one percent of the incident strains were lysed by phages of group III or I/III.

Biological properties, drug sensitivity and phage types of staphylococci isolated from rats (Rattus norvegicus) and swine

In order to search for the source of staphylococci responsible for food poisoning, studies were made on some properties of staphylococci isolated from rats (Rattus norvegicus) and swine, both of which had close relations with human beings. These staphylococci had been isolated from the nose of swine and the skin of rats. Coagulase-positive staphylococci were derived from 65 (50%) of 130 rats and 58 (85%) of 68 swine. These isolates were proved to have the following biological characters, drug sensitivity, and phage type.1. All the strains of coagulase-positive staphylococci isolated from rats and swine produced DNase, phosphatase and lysozyme, and reduced nitrate.2. Only 34 percent of the coagulase-positive strains isolated from rats showed β hemolysis, while almost all the strains (97%) isolated from swine were β hemolytic.3. The biological properties of the strains of rat origin were not always the same as those of swine origin. There were differences between the two in such respects as colonial color, lipase production, gelatin liquefaction, coagulation and later peptonization of litmus milk, hydrolysis of esculin, and egg reaction.4. Forty percent of the strains of rat origin were relatively resistant to penicillin, showing a susceptibility higher than 25u/ml. Thirty-five percent of the strains of rat origin and 83 percent of those of swine origin were relatively resistant to streptomycin (susceptibility higher than 12.5mcg/ml). Only 13 percent of the strains of swine origin were relatively resistant to tetracycline (higher than 12.5mcg/ml). About 80 percent of the strains isolated from both animal species were resistant to sulfathiazole (higher than 100mcg/ml). All the strains tested, however, were sensitive to chloramphenicol, oleandomycin, and erythromycin (less than 6.3mcg/ml). All the strains that were relatively resistant to penicillin and streptomycin formed yellow colonies on solid medium and were proved to be α hemolytic.5. Typing was carried out on these isolates using the basic set of typing phages which has been selected by the International Committee. Eighty-one percent of 58 strains of swine origin were successfully typed. Three-fourths of the strains which had been typed by this set of phages showed susceptibility to group II, and the rest of them belonged to the mixed group. On the other hand, only 17 percent of the strains of rat origin was found to be typable and belong to group III without exception.6. It can generally be mentioned that the properties of some of the strains of rat origin were closely related to those of the strains isolated from the cases of staphylococcal food poisoning, while the strains isolated from swine were considerably different from those from human beings.From these results, it is quite probable that the rat is playing an important role as a source of contamination in the case of staphylococcal food poisoning.

IMITATION CREAM FILLING AS A VEHICLE OF STAPHYLOCOCCAL FOOD POISONING

SummaryAfter two cases of staphylococcal food poisoning were attributed to doughnuts containing imitation cream filling, dispensed from an unrefrigerated vending machine, a batch of this filling was inoculated with food poisoning stayhylococci to determine its ability to support growth. Three staphylococcus cultures were employed: culture K which carne from the doughnut filling that prompted this study; culture D which was recovered from chocolate eclairs incriminated in an outbreak in 1961; and culture T which was isolated from turkey responsible for an outbreak in 1962. All cultures grew at both 25 C and 32 C in 20 hr and 40 hr. However, cultures K and D developed larger populations than T, the turkey strain. This emphasizes the need for refrigeration of imitation cream fillings from the time of manufacture to the time of sale.

Bacteria Associated with Giblets of Commercially Processed Turkeys

CONTAMINATED products made from turkey meat are important sources of food borne intoxications and infections. Dack (1962) reported that turkeys accounted for 14 of 137 outbreaks of staphylococcal food poisoning during the years 1956–1961. According to Dauer (1961) turkey meat was associated with four outbreaks involving 350 cases of salmonellosis and eight outbreaks responsible for 682 cases of staphylococcal food poisoning in 1960.The most probable source of salmonellae on turkey carcasses has been reported to be the viscera and intestinal contents (Gunderson et al., 1954). Morris and Ayres (1960) recovered Salmonella spp. from only 12 of 2,500 samples taken in a federally inspected turkey processing plant. None of the positive cultures were recovered from the carcass surface after evisceration or from the drainage from giblets. Sadler et al. (1961) isolated Salmonella species from 2.4% of the intestinal or cecal samples of turkeys on the processing line.Incidence and…