Isolation and characterization of Staphylococcus argenteus strains from retail foods and slaughterhouses in Japan.

Staphylococcus argenteus has been recently established as a novel species of Staphylococcus aureus complex. It is known to cause various human diseases, such as skin and soft-tissue infections, sepsis, and staphylococcal food poisoning, although the source of infection has not been clearly described. In food poisoning cases, the source of bacterial contamination in food is unknown. This study examined the prevalence of S. argenteus among retail fresh food and poultry slaughterhouses in Japan. Among 642 food samples examined, successful isolation of S. argenteus was achieved in 21 of 151 (13.9%) chicken samples. No isolations from pork, beef, fish, or vegetables in retail markets were confirmed. Multiple-locus sequence typing revealed that the 21 isolates were classified into four sequence types (ST) that were divided into 14 subtypes using spa-typing. All food isolates were susceptible to methicillin and did not show positivity for the Panton-Valentine leukocidin gene. When bacteria were isolated from two poultry slaughterhouses in the same region, 14 S. argenteus strains were successfully isolated from only one slaughterhouse. Thirteen of 14 strains were isolated from a poultry carcass and slaughterhouse environments during a certain sampling period and were all classified as ST5961 with identical spa-type. Also, the number of single nucleotide variants (SNVs) detected on the core genomes of the same 13 strains were between 0 and 17, suggesting a long-term inhabitation of an S. argenteus strain inside the facility. Furthermore, one isolate from chicken meat was also genetically linked with the same lineage of slaughterhouse isolates, with ≤15 SNVs being detected. Additionally, one slaughterhouse isolate from chiller water and three chicken isolates were classified into the same cluster by phylogenetic analysis, although the number of pairwise SNVs ranged from 62 to 128. To the best of the authors' knowledge, this is the first study that demonstrated S. argenteus in a food processing facility and the possible bacterial contamination on food during food processing.

Reviewing the polyolefin cyclization reaction of the c(35) polyprene catalyzed by squalene-hopene cyclase.

A review of the polycyclization reaction of the C(35) polyprenoid by squalene-hopene cyclase: Surprisingly, our results completely disagree with a previous publication in which it was reported that a hexacyclic skeleton was constructed as the single product. In our work many tri- and tetracyclic scaffolds were isolated, but no penta- or hexacycles. The reasons for the different results and the mechanism of the polycyclization reaction are discussed (see figure).Squalene-hopene cyclase (SHC) catalyzes the polycyclization of squalene (C(30)) to the pentacyclic hopene with regio- and stereochemical specificity. In this study, we reviewed the polycyclization reaction of the C(35) polyprenoid catalyzed by SHC. Surprisingly, our results completely disagreed with a previous publication in which it was reported that a hexacyclic skeleton was constructed as the single product in 10 % yield (I. Abe, H. Tanaka, H. Noguchi, J. Am. Chem. Soc. 2002, 124, 14514-14515). Our experimental results showed that many tri- and tetracyclic products, up to 12, including novel carbocyclic cores, were generated in a high conversion ratio (97 %), but no detectable amounts of the penta- and hexacycle were produced. The mechanisms for the formation of the C(35) polyprene products isolated by us are discussed in this paper. The following four conformations were generated during the polycyclization cascade: chair-chair-boat, chair-chair-chair, chair-chair-chair-boat, and chair-chair-chair-chair. Larger amounts of the false intermediates with 13alpha-H (tricycle) and 17alpha-H (tetracycle) were produced compared with the true intermediates (13beta-H and 17beta-H), which indicates that the C(35) polyprene cannot fold correctly in the enzyme cavity due to the extra C(5) unit appended to squalene. This would have promoted the formation of the aborted cyclization products with tri- and tetracycles. In addition, the fact that no penta- or hexacyclic products were formed further indicates that SHC does not have sufficient space to accommodate the entire carbon framework of C(35).

A case of sick building syndrome in a Japanese office worker.

The adverse health effects caused by indoor air pollution are termed "sick building syndrome". We report such a patient whose symptoms appeared in the workplace. A 36-year-old female office worker developed nausea and headache during working hours in a refurbished office. After eight months of seeking help at other clinics or hospitals without improvement, she was referred to our hospital. At that time she reacted to the smells of various chemicals outside of the office building. Biochemical findings were all within normal ranges. Specific IgE antibody to cedar pollen was positive and the ratio of TH1/TH2 was 4.5. In the Eye Tracking Test (ETT), vertical eye movement was saccadic. Her anxiety level was very high according to the State-Trait Anxiety Inventory (STAI) questionnaire. Subjective symptoms, ETT findings and anxiety levels on STAI gradually improved during two years of follow-up. One year after the onset of her illness, the formaldehyde concentrations in the building air ranged from 0.017-0.053 ppm. Even though relatively low, chemical exposure from building materials such as formaldehyde induced a range of symptoms. Also, lack of recognition by superiors and doctors that sick building syndrome might have been the source of her illness coupled with her high state of anxiety may have exacerbated her symptoms and led to the onset of multiple chemical sensitivity. Thus psychosocial factors may contribute to sick building syndrome in the workplace.

Characterization of multidrug-resistance phenotypes and genotypes of Escherichia coli strains isolated from swine from an abattoir in Osaka, Japan.

A total of 455 highly tetracycline-resistant Escherichia coli strains were isolated from 84 healthy swine from abattoirs and it was found that 56.9, 43.1, 22.2, 15.4, 2.6 and 1.5% of strains were resistant to chloramphenicol, ampicillin, kanamycin, trimethoprim-sulphamethoxazole, ofloxacin and gentamicin respectively. Interestingly, E. coli strains isolated from certain finisher hog groups exhibited resistance against 2-7 antimicrobials, but strains isolated from multiparous sow groups in each herd were resistant to only 2-4 antimicrobial agents. When randomly selected 108 tetracycline-resistant isolates were tested for the presence of resistance genes, the following genes tet(A) (n = 6), tet(B) (n = 95), tet(D) (n = 1) or both tet(A) and tet(B) (n = 6) were found to be distributed among them. Furthermore, 52 isolates carried the integrase 1 gene and 24 strains gave five different PCR amplicon profiles using primers from the variable region of integron. Extensive nucleotide sequence analyses of these amplicons revealed the presence of dhfrI, dhfrXII, dfr17, aadA, aadA2, aadA5, aadA21, aacA4 and catB3 genes which code for different antibacterial resistance proteins.

Enzymatic cyclization reactions of geraniol, farnesol and geranylgeraniol, and those of truncated squalene analogs having C20 and C25 by recombinant squalene cyclase.

The substrate specificity of squalene-hopene cyclase was investigated using the C10-C25 analogs including naturally occurring substances, e.g. geraniol (C10), farnesol (C15) and geranylgeraniol (C20). No cyclization occurred for geraniol, but a significantly high conversion ratio (64%) was observed for farnesol, yielding the cyclic sesquiterpenes consisting of 6/6-fused bicyclic ring systems. Among them, an attractive compound having C30 was produced, in the structure of which acyclic the farnesol unit is linked to the bicyclic skeleton through ether linkage. Conversion of geranylgeraniol was low (ca. 12%). The squalene analogs having C20 and C25 also were cyclized in yields of ca. 33-36%, but the analogs having the methyl group at C7 and/or at C11 underwent no cyclization; the large steric bulk size of C7-Me and/or C11-Me, which is arranged in [small alpha]-disposition for all the pre-chair conformation, would have interacted repulsively with the cyclase recognition site near to the C7 and/or C11, resulting in no construction of the all-chair conformation inside the reaction cavity. A relatively low yield of geranylgeraniol indicated that a less bulky hydrogen atom must be located at C14 for the efficient polycyclization reaction. The squalene cyclase shows remarkably broad substrate specificity to accept the truncated analogs having carbon-chain lengths of C(15)-C25 in addition to C30.