Foodborne Outbreaks Caused by Human Norovirus GII.P17-GII.17-Contaminated Nori, Japan, 2017.

Seven foodborne norovirus outbreaks attributable to the GII.P17-GII.17 strain were reported across Japan in 2017, causing illness in a total of 2,094 persons. Nori (dried shredded seaweed) was implicated in all outbreaks and tested positive for norovirus. Our data highlight the stability of norovirus in dehydrated food products.

FRI-4 carbapenemase-producing Enterobacter cloacae complex isolated in Tokyo, Japan.

Objectives: A carbapenem-resistant Enterobacter cloacae complex isolated in Tokyo, Japan, produced a carbapenemase that was detected by a Carba NP test and a modified carbapenem inactivation method, but none of the 'Big Five' carbapenemase genes was detected by PCR. This study aimed to identify the carbapenemase. Methods: Carbapenemase genes were screened by WGS. Next, we generated a recombinant plasmid in which the carbapenemase gene was inserted. We also extracted the carbapenemase gene-carrying plasmid from the E. cloacae complex. The effects of both plasmids on the antibiotic susceptibility of Escherichia coli were then tested. The carbapenemase gene-carrying plasmid in the E. cloacae complex was completely sequenced. Results: A novel carbapenemase gene, blaFRI-4, encoded an amino acid sequence that was 93.2% identical to French imipenemase (FRI-1). E. coli transformed with blaFRI-4 showed reduced carbapenem susceptibility. A complete sequence of the blaFRI-4-carrying 98 508 bp IncFII/IncR plasmid (pTMTA61661) showed that blaFRI-4 and the surrounding region (18.7 kb) were duplicated. Conclusions: The FRI-4-producing E. cloacae complex was isolated in Japan, whereas all other FRI variants have been found in Europe, suggesting that the spread of FRI carbapenemases is global.

Whole genomic analysis of human G8P[14] group A rotavirus detected from community gastroenteritis outbreak.

Several suspected cases of zoonotic transmission of group A rotavirus (RVA)-related gastroenteritis were reported previously. In August 2012, G8P[14] RVA was detected in fecal specimens from a community gastroenteritis outbreak occurring during a school trip. In this study, additional analyses were performed and it was found that this strain had the G8-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3 sequence, similar to bovine-like RVA strains. Some contamination by emesis and diarrheic feces was observed near a rest room in the lodging area. Contact history with animals was unknown in members of this school trip, and this case implied that the strain may have acquired the ability for person-to-person transmission.

Comparison between patients with norovirus-related gastroenteritis and asymptomatic carriers with respect to distribution of antibody-complexed viral particles and intestinal flora.

Asymptomatic carriers have a major influence on the spreading of norovirus infections. The objective of this study was to examine the characteristics of patients and asymptomatic carriers affected by norovirus-related community gastroenteritis outbreaks. No significant difference between the two groups was observed in terms of the number of norovirus-antibody complexes with respect to total numbers. Principal coordinates analysis of the intestinal flora based on ß-diversity analysis, revealed a different bacterial composition between patients and asymptomatic carriers, particularly regarding the genera Pseudomonas, Bacteroides, and Erwinia, as well as the Ruminococcaceae family. Although the proportional changes between these intestinal microorganisms were not sufficient to explain gastroenteritis symptoms, they represent possible markers shared by asymptomatic norovirus carriers.

[Molecular Epidemiological Analysis of Hepatitis A Viruses Circulating in Tokyo, 2016-2017].

Hepatitis A virus (HAV) is a common infectious agent that causes acute hepatitis worldwide. Since the incubation period of HAV infection is about one month, it is difficult to identify the source of infection based only on medical interviews. Molecular epidemiological analysis of HAV isolated from patients can help to reveal the infection route and to identify diffuse outbreaks caused by common food vehicles. In the present study, samples were collected from 108 cases notified to the active epidemiological investigation system in Tokyo between 2016 and 2017. Samples found to be HAV-positive by semi-nested RT-PCR were subjected to sequencing and phylogenetic analysis; the results were analyzed together with the epidemiological data. HAV was detected in 99 out of 108 cases. Phylogenetic analysis showed that the 99 HAV strains were divided into 91 of genotype IA, two of IB, and six of IIIA. The 91 HAV strains typed as IA were further divided into four main line-ages, IA-1, IA-2, IA-3, and IA-4, each with a unique epidemiological background. Our nucleotide sequence database of HAV and epidemiological background data will be helpful to investigate sources of infection and the epidemiology of hepatitis A cases in the future.

[An autochthonous outbreak of dengue type 1 in Tokyo, Japan 2014].

OBJECTIVES: An outbreak of autochthonous dengue fever was reported in August 2014, with cases suspected mainly from Yoyogi Park in Tokyo. This is the first epidemic of dengue fever in Japan since 1945. METHODS: From August to October 2014, the following measures were taken to control the outbreak: 1) risk communication and information sharing; 2) active case finding; 3) vector surveillance in affected sites; and 4) laboratory testing. We also reviewed the surveillance data as reported to the National Epidemiological Surveillance of Infectious Diseases during the 44 epidemiological weeks. results: An official dengue fever call center was set up temporarily for the general public and 3,005 calls were received. The Tokyo Metropolitan Government issued 39 press releases regarding patients and nine related to dengue virus (DENV) detection and vector control activities for the media. Confirmed autochthonous dengue fever cases were reported between the 35th and 44th epidemiological weeks. Out of 160 cases of outbreak, 108 (67.5%) confirmed cases were reported in Tokyo. The estimated illness onset dates were between August 9 and October 7, and estimated dates of infections were between August 3 and October 3, 2014. The data suggest that the infective mosquitoes had already been present in Yoyogi Park at the end of July 2014. During the weekly vector surveillance at Yoyogi Park, a total of 1,152 adult mosquitoes, of which 856 (73.3%) were Aedes mosquitoes, were collected over 11 weeks by a light trap with dry ice. DENV was detected from adult Aedes mosquito samples collected on the 2nd, 9th, and 16th of September, 2014. Serum samples from 240 suspected cases were examined at the Tokyo Metropolitan Institute of Public Health, and 78 were positive for the DENV NS1 antigen, DENV-specific IgM antibody, or DENV nucleic acid with reverse transcriptase polymerase chain reaction (RT-PCR) (NS1: 66 cases; IgM: 50 cases; PCR: 57 cases). Genetic analysis of DENV-positive serum and mosquito samples found all to be categorized as DENV-serotype 1 (gene type I). Phylogenetic analysis of the envelope protein genome sequence from patients and mosquitoes in Tokyo revealed more than 99% similarity with each other and with the strain from the first outbreak-associated patient in Saitama. CONCLUSION: Measures important for control of infectious disease epidemic were learned during this recent indigenous dengue outbreak in Tokyo. It also highlighted the importance of preparedness for epidemics of indigenous or imported infectious diseases, especially in light of the fact that Tokyo is in preparation for the Olympic and Paralympic Games in 2020.

Decision-making deficit of a patient with axonal damage after traumatic brain injury.

Patients with traumatic brain injury (TBI) were reported to have difficulty making advantageous decisions, but the underlying deficits of the network of brain areas involved in this process were not directly examined. We report a patient with TBI who demonstrated problematic behavior in situations of risk and complexity after cerebral injury from a traffic accident. The Iowa gambling task (IGT) was used to reveal his deficits in the decision-making process. To examine underlying deficits of the network of brain areas, we examined T1-weighted structural MRI, diffusion tensor imaging (DTI) and Tc-ECD SPECT in this patient. The patient showed abnormality in IGT. DTI-MRI results showed a significant decrease in fractional anisotropy (FA) in the fasciculus between the brain stem and cortical regions via the thalamus. He showed significant decrease in gray matter volumes in the bilateral insular cortex, hypothalamus, and posterior cingulate cortex, possibly reflecting Wallerian degeneration secondary to the fasciculus abnormalities. SPECT showed significant blood flow decrease in the broad cortical areas including the ventromedial prefrontal cortex (VM). Our study showed that the patient had dysfunctional decision-making process. Microstructural abnormality in the fasciculus, likely from the traffic accident, caused reduced afferent feedback to the brain, resulting in less efficient decision-making. Our findings support the somatic-marker hypothesis (SMH), where somatic feedback to the brain influences the decision-making process.

Emergence of Phytobacter diazotrophicus carrying an IncA/C2 plasmid harboring bla NDM-1 in Tokyo, Japan.

Phytobacter diazotrophicus is an Enterobacterales species that was originally identified as a plant growth-promoting, Gram-negative bacterium. Recently, this species has been recognized as relevant to opportunistic human and nosocomial infections in clinical settings. Its frequent misidentification as other Enterobacterales species from clinical examination occasionally causes a delay in the identification of nosocomial outbreaks. Here, we report the emergence of New Delhi metallo-ß-lactamase (NDM)-producing P. diazotrophicus isolated from hospitalized pediatric patients and hospital environments in Tokyo, Japan. In our case, these isolates were found during an investigation of carbapenem-resistant Enterobacterales in relation to nosocomial infections. Whole-genome sequencing is useful for overcoming the difficulty of species identification. Furthermore, we found that bla NDM-1 was carried by an IncA/C2 plasmid (approximately 170 kbp), which was transferrable from the clinical isolates to the recipient strain Escherichia coli J53. Our study demonstrated that P. diazotrophicus behaves as a carrier of bla NDM-harboring plasmids, potentially disseminating resistance to carbapenems among Enterobacterales. IMPORTANCE Early detection of nosocomial outbreaks is important to minimize the spread of bacteria. When an outbreak is caused by multidrug-resistant bacteria such as carbapenem-resistant Enterobacterales, a delay in findings makes it difficult to control it because such bacteria often spread not only among human patients but also in hospital environments. Phytobacter diazotrophicus, an Enterobacterales species that has recently been found to be relevant to clinical settings, is often misidentified as other bacteria in clinical laboratories. Here, we found NDM-producing P. diazotrophicus in hospitalized pediatric patients and their environment in Tokyo, Japan. Given that the isolates carried bla NDM-1-harboring transferrable plasmids, the influence of such bacteria could be greater with the mediation of horizontal transfer of carbapenem resistance. Our findings suggest that P. diazotrophicus should be recognized as an NDM-carrier, for which more attention should be paid in clinical settings.

Bone scan can be spared in asymptomatic prostate cancer patients with PSA of <=20 ng/ml and Gleason score of <=6 at the initial stage of diagnosis.

OBJECTIVE: According to several guidelines, it is acceptable to spare a bone scan in the patients who are newly diagnosed with low-risk prostate cancer. Our aim is to clarify a suitable group whereby a bone scan could be spared at the initial staging of prostate cancer. METHODS: Consecutive 857 patients who were newly diagnosed from 2004 through 2009 and received bone scans using technetium 99m methylene diphosphonate at the initial staging were enrolled. The proportion of positive bone metastases by age distribution, prostate-specific antigen level at diagnosis, Gleason score and clinical T stage were evaluated. Univariate and multivariate logistic regression analyses were performed to identify the predictors of positive bone metastases. RESULTS: Of all 857 patients, 40 patients (4.7%) showed bone metastases. Patients with higher age, prostate-specific antigen level, clinical stage and Gleason score showed significantly higher rate of bone metastases (P < 0.001). In univariate logistic regression analyses, age, prostate-specific antigen level, clinical stage and Gleason score were independent predictors of bone metastasis. The multivariate analysis showed that both the prostate-specific antigen level >50 ng/ml and the Gleason score ≥4 + 3 were independent predictors of bone metastases. CONCLUSIONS: The incidences of bone metastases in patients with a prostate-specific antigen level of ≤20 ng/ml and Gleason score of ≤6 were reasonably low. Collectively, a bone scan is not necessary as a routine examination for these patients at their initial staging of prostate cancer.

Benzodiazepine receptor imaging in an adult with Rasmussen's encephalitis and epilepsia partialis continua.

We describe an adult with Rasmussen's encephalitis associated with widespread decreased accumulation of tracer on 123-I iomazenil (IMZ) SPECT. The patient had a form of epilepsia partialis continua and neurological deterioration associated with hemiatrophy. Cranial MRI showed cerebral atrophy in the left frontal, parietal, and temporal lobes, without abnormal intensity. Delayed IMZ SPECT showed widespread decreased accumulation of tracer in the left temporal and frontal regions. An early scan showed mildly decreased accumulation in the left temporal and frontal regions. Three-dimensional stereotactic surface projection (3D-SSP) analysis showed that the decreased regions on delayed IMZ images were slightly larger as compared with the previous IMZ study performed. Some regions without decreased accumulation of tracer on Tc-ECD or early IMZ images showed decreased accumulation on delayed IMZ images. This case study suggests that benzodiazepine receptors may be reduced in the affected hemisphere of patients with Rasmussen's encephalitis.

Molecular Characteristics of Novel Mono-Reassortant G9P[8] Rotavirus A Strains Possessing the NSP4 Gene of the E2 Genotype Detected in Tokyo, Japan.

Rotavirus A (RVA) has been detected in patients with gastroenteritis even after vaccine introduction in Japan. To investigate circulating RVA strains, RVA-positive stool specimens obtained in Tokyo in 2017 and 2018 were analyzed using next-generation sequencing. A total of 50 and 21 RVA samples were obtained in 2017 and 2018, respectively. In 2017, G2P[4] (40.0%) was the most prevalent strain, followed by G3P[8] (DS-1-like) (28.0%), G8P[8] (10.0%), G3P[8] (Wa-like) (8.0%), G9P[8]-E1 (8.0%), and mixed infection (6.0%). In 2018, G3P[8] (DS-1-like) (28.6%) and G9P[8]-E2 (28.6%) were the most prevalent strains, followed by G9P[8]-E1 (19.0%), G2P[4] (9.5%), G8P[8] (9.5%), and mixed infection (4.8%). Six G9P[8]-E2 strains detected in 2018 showed an atypical genotype constellation (G9P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1), which had not been reported previously. Phylogenetic analyses suggested that the RVA virus was generated by inter-genogroup reassortment between commonly circulating G9P[8] and G2P[4] strains in Japan. The G9P[8] strain seemed to be reassorted with only the NSP4 gene of the E2 genotype of the G2P[4] strain. Since this newly-emerged G9P[8]-E2 virus was detected in different locations in Tokyo, the virus appears to have already begun to spread to a wider area.

Seroprevalence of Entamoeba histolytica at a voluntary counselling and testing centre in Tokyo: a cross-sectional study.

BACKGROUND: Amebiasis, which is caused by Entamoeba histolytica, is a re-emerging public health issue owing to sexually transmitted infection (STI) in Japan. However, epidemiological data are quite limited. METHODS: To reveal the relative prevalence of sexually transmitted E. histolytica infection to other STIs, we conducted a cross-sectional study at a voluntary counselling and testing (VCT) centre in Tokyo. Seroprevalence of E. histolytica was assessed according to positivity with an ELISA for E. histolytica-specific IgG in serum samples collected from anonymous VCT clients. RESULTS: Among 2083 samples, seropositive rate for E. histolytica was 2.64%, which was higher than that for HIV-1 (0.34%, p<0.001) and comparable to that for syphilis (rapid plasma reagin (RPR) 2.11%, p=0.31). Positivity for Chlamydia trachomatis in urine by transcription-mediated amplification (TMA) was 4.59%. Seropositivity for E. histolytica was high among RPR/Treponema pallidum hemagglutination (TPHA)-positive individuals and it was not different between clients with and without other STIs. Both seropositivity of E. histolytica and RPR were high among male clients. The seropositive rate for anti-E. histolytica antibody was positively correlated with age. TMA positivity for urine C. trachomatis was high among female clients and negatively correlated with age. Regression analysis identified that male sex, older age and TPHA-positive results are independent risk factors of E. histolytica seropositivity. CONCLUSIONS: Seroprevalence of E. histolytica was 7.9 times higher than that of HIV-1 at a VCT centre in Tokyo, with a tendency to be higher among people at risk for syphilis infection. There is a need for education and specific interventions against this parasite, as a potentially re-emerging pathogen.

Molecular identification and characterization of Sarcocystis spp. in horsemeat and beef marketed in Japan.

Human Sarcocystis infections are known to be caused by the ingestion of raw or undercooked beef or pork containing mature sarcocysts of Sarcocystis hominis or S. suihominis, respectively. In addition, several cases of parasitic food poisoning in Japan have recently been reported after consumption of raw horsemeat containing sarcocysts of S. fayeri. In this study, the presence of sarcocysts in 28 horsemeat and 121 beef samples collected in Tokyo was investigated. Sarcocysts of S. fayeri were found in 16 horsemeat samples. Sarcocysts of S. hominis were not detected in beef samples, while sarcocysts of S. cruzi were detected in 60 beef samples. In addition, S. hirsuta and S. bovini were isolated only from New Zealand beef samples. Bradyzoites in sarcocysts collected from 62/73 sarcocyst-positive refrigerated horsemeat and beef samples were determined to be viable. Molecular analysis of S. fayeri 18S rRNA gene sequences revealed that intraspecific variation among eight individual bradyzoites from a single sarcocyst was as high as 9.8%. In contrast, mitochondrial cytochrome c oxidase subunit 1 (mtDNA cox1) gene sequences from the six fragments of a single sarcocyst were 100% identical. Sarcocysts of S. bovini isolated from beef also exhibited intraspecific variation in 18S rRNA gene sequences and had to be cloned before sequencing, while mtDNA cox1 gene sequences were obtained by direct sequencing. Therefore, we conclude that molecular analysis of the mtDNA cox1 gene is the most useful for identification of Sarcocystis species. This study provides the first published partial sequence of the S. fayeri mtDNA cox1 gene.

Early dynamic SPECT imaging in acute viral encephalitis.

BACKGROUND AND PURPOSE: Several cases have reported that dynamic single-photon emission computed tomography (SPECT) shows increased tracer uptake in acute herpes simplex viral encephalitis (HSVE). The purpose of this study was to evaluate the clinical usefulness of dynamic Tc-ECD SPECT in patients with acute viral encephalitis. METHOD: We performed the dynamic SPECT in 9 patients with acute viral encephalitis (4 women, 5 men, 49.5 +/- 17.4 years of age at onset). SPECT and magnetic resonance imaging (MRI) were performed within 2 weeks after acute clinical onset and at the time of resolution of acute symptoms. RESULTS: Cranial MRI showed high intensities in all patients (7 medial temporal and 2 lateral temporal lobes, 1 inferior temporal lobe, 2 insula and adjacent regions, 1 thalamus, 1 putamen). The initial dynamic SPECT showed increased accumulation of tracer, corresponding to the lesions on MRI in 3 patients with HSVE. Resolution of acute symptoms was associated with a reduction in increased tracer uptake. Six patients with non-HSVE showed no increased accumulation of tracer. CONCLUSIONS: Dynamic SPECT may be a new optional neuroradiologic technique that may help to establish a diagnosis in patients with suspected HSVE.

Physical and histopathological assessment of the effects of metallic stents on radiation therapy.

To evaluate whether simultaneous metallic stent (MS) placement and radiotherapy are feasible, phantom and animal experiments were performed. The interface dose by external irradiation (EI) or intracavity irradiation (II) to 5 kinds of MS was measured using the charge-coupled device (CCD) camera with a thermoluminescent (TL) sheet, and backscatter and absorption were evaluated using composite method. Lineac 10 MV X-ray irradiated the MS in close contact with the TL sheet. II was performed using (192)Ir, and the irradiation dose transmitted through the MS was measured using the TL sheet. The ratio of the CCD value of the MS wire region to that of the MS non-wire region was defined as the dose perturbation factor (DPF). Furthermore, the effects of a combination of (60)Co gamma-ray EI and MS placement in the normal common bile duct were histopathologically evaluated in dogs. In the phantom experiments of EI, in backscatter by the MS, the DPF was 1.09 for CZ, and 1.03 for Pal, but no backscatter was detected in the remaining 3 MS. In absorption by the MS, the DPF was 0.92, 0.97, 0.97, and 0.98 for CZ, Wall, Pal, and Vel, respectively, but no absorption was detected in U. Flex. In those of II, the DPF of absorption was 0.91, 0.98, and 0.98 for CZ, U. Flex, and Wall, respectively, but no absorption was detected in Pal and Vel. The animal experiments showed infiltration of inflammatory cells and fibrosis in the case of both MS placement and EI. These changes were marked in EI treating after MS placement, but neither severe ulcer nor perforation was found. In conclusion, these results suggested that the effect of MS should be considered carefully when simultaneous MS placement and EI is performed clinically.

SPECT revealed cortical dysfunction in a patient who had genetically definite megalencephalic leukoencephalopathy with subcortical cysts.

We describe the findings on single photon emission computed tomography (SPECT) in a patient who had genetically definite megalencephalic leukoencephalopathy with subcortical cysts. Technetium-99m-ethyl cysteinate dimer SPECT revealed hypoperfusion in the cerebral white matter, which had shown high signal intensity on magnetic resonance imaging (MRI) T2 images. Hypoperfusion was also unexpectedly found in the frontal cortices, which showed no abnormalities on MRI. This frontal abnormality corresponded clinically to a low score on the frontal assessment battery. Decreased GABA receptor density as suggested by (123)I-Iomazenil SPECT provided further evidence of cortical neuron dysfunction. Although confirmation must await future larger-scale SPECT and functional studies, our findings suggest that SPECT can be used to non-invasively monitor in vivo cortical function in this disease.

[Development of multiplex real-time PCR assay for the detection of herpes simplex virus types 1 and 2].

We developed a multiplex real-time PCR assay to simultaneously detect herpes simplex virus-1 (HSV-1) and HSV-2 genomes. TaqMan PCR primer pairs and fluologenic probes targeting the HSV-1 or HSV-2 gpD region were originally designed. The detection limit was 15 copies/tube, and the quantitative range was from 15 to 1.5 x 10(6) copies/tube of HSV-1 or HSV-2 DNA. The sensitivity of this assay was 10(3) times higher than the conventional PCR assay. No other herpes virus DNA-Cytomegalovirus, Epstein-Barr virus, human herpes virus 6, human herpes virus 7, or varicella-zoster virus-were detected by this assay. These results indicated that the multiplex real-time PCR assay is useful for rapidly diagnosing HSV-1 and HSV-2.

[Serial Food Poisoning Outbreaks Caused by Norovirus-Contaminated Shredded Dried Laver Seaweed Provided at School Lunch, Tokyo, 2017].

In February 2017, four food poisoning outbreaks occurred in Tokyo, involving ten schools. Shredded dried laver seaweed processed by a single food manufacturer in December 2016 was provided in common for the school meals that caused all four outbreaks. Of 4,209 persons exposed, 1,193 (28.3%) had symptoms of gastroenteritis. Norovirus (NoV) GII was detected in 207 (78.1%) of 265 cases by real-time RT-PCR. Thirty-one shredded dried laver seaweed samples were examined and seven (22.6%) of them were positive for NoV GII. PCR fragments of NoV ORF1/2 junction region (302 bp) from seven shredded dried laver seaweed samples and 20 clinical samples derived from the four outbreaks were sequenced. All of them displayed complete homology, and the genotype was classified as GII.17. A nearly full-length sequence (7,420 bp) of NoV RNA derived from a case was obtained by next-generation sequencer analysis and phylogenetic analysis indicated that this strain belongs to the same cluster as Hu/GII/JP/2015/GII.P17_GII.17/Kawasaki308. Thus, our investigation elucidated that the causative agent of these four serial food poisoning outbreaks was NoV GII.17 and the infectious source was a single batch of shredded dried laver seaweed. The water activity of the shredded dried laver seaweed was found to be 0.119 to 0.129. It was epidemiologically clarified that NoV does not lose infectivity for about two months even in the dry state. We conclude that a large diffuse outbreak of food poisoning caused by NoV GII.17 contamination of shredded dried laver seaweed had occurred in Tokyo. Our elucidation of the causative agent indicated that the food poisoning outbreaks in multiple areas of Japan, including Tokyo, during January to February 2017 were caused by the same contaminated food.

[Evaluation of immunochromatography test for rapid detection of influenza A and B viruses using real-time PCR].

The sensitivity of rapid diagnostic kits to influenza B is lower than to influenza A. The cause-poor performance of the kit or the scarcity of viruses in type B specimens-has yet to be clarified. Using real-time PCR, we measured the amount of influenza viruses with nasopharyngeal aspirate fluid previously identified by virus isolation culture and passing the rapid diagnosis test by four types of kits, including the ESPLINE Influenza A&B-N (Fujirebio Corp., Japan). We classified the results of virus isolation and rapid diagnosis tests into three groups and examined them: group 1 (12 specimens, influenza B, all negative in tests using four types of kits); group 2 (57 specimens, influenza B, all positive in tests); and group 3 (36 specimens, AH3, all positive in tests). The average amount of viruses in group 1 (6.60 +/- 0.81 log10copies/mL) was significantly lower (p<0.0001) than that in group 2 (8.51 +/- 0.57 log10copies/mL) or group 3 (8.72 +/- 0.63 log10copies/mL). No significant difference was seen in the amount of viruses between groups 2 and 3. We concluded that the cause of low sensitivity in rapid diagnostic kits to influenza B are attributable to the scarcity of viruses in the specimen.

[Development of effective detection method for Coxiella burnetii in mayonnaise by real-time PCR and investigation of C. burnetii contamination in commercial mayonnaise in Tokyo].

A PCR method for the effective detection of Coxiella burnetii in commercially available mayonnaise was developed. Sample preparations were isolated from 50 g portions of each mayonnaise product by four successive extraction steps in phosphate buffer with 2.0 M NaCl. These extracts were then centrifuged at 20,000 x g for 60 min. DNA was isolated from the solution containing the precipitate with a commercial kit, and amplified quantitatively using real-time PCR that targeted the com1 region of C. burnetii. The recoveries of C. burnetii from 2 kinds of commercial mayonnaise specimens, with a baseline control of 1 x 10(7) particles of the Nine Mile phase II strain, were 85.0 +/- 6.0% and 72.0 +/- 0.4%, respectively. The determination limit of this method was 500 C. burnetii particles per 50 g of mayonnaise. The DNA specimens isolated from 50 different commercial mayonnaise samples sold in Tokyo using this method were amplified using both nested PCR and real-time PCR. No contamination by C. burnetii was detected in any of the mayonnaise samples.