With the aim of setting up an animal model of Shigella dysenteriae-induced diarrhea, Wistar rats received per os increasing densities of S. dysenteriae type 1 (Sd1). Inoculum of 12×10⁸ Sd1 provoked dysenteric diarrhea within 24 h. Feces of healthy rats were molded, brown to black and rough. Rats developing diarrhea presented blood at the anal orifice; stools were soft or liquid containing mucus, or molded, smooth and mucus-coated. At times, stools appeared longer, dark and shiny due to the presence of mucus and blood, or molded, lumpy and brittle. Diarrheal induction was associated with abdominal ailment, progressive increase in stool weight and frequency, and increase in bacterial population. Sixty-seven percent of the total number of deaths had occurred by day 6 after diarrheal induction. These results indicate that Sd1 induced in rats a model of shigellosis which might be helpful for physiopathological and pharmacological studies of this type of infectious diarrhea.

The study was designed to compare antibiotic use, cost and consumption before and after an initiation of an antibiotic-restriction policy in our hospital. The policy was applied in 2003, and the prescription of two groups of antibiotics (intravenously used and expensive antibiotics) was restricted. A prescription for the restricted antibiotics could be obtained with approval by an infectious disease specialist (IDS). All the hospitalized patients who received antibiotics were evaluated by a cross-sectional study with standard criteria. The annual cost and consumption of antibiotics were evaluated. After restriction, the rate of antibiotic use decreased from 52.7 to 36.7% (P < 0.001), and the appropriate use increased from 55.5 to 66.4% (P < 0.05). Appropriate use was higher for restricted antibiotics (88.4%) than for unrestricted ones (58.2%) (P < 0.001), and higher in the presence of ID consultation (97.5%) than in the absence of consultation (55.7%) (P < 0.001). Culture-based treatment was increased, and appropriate use in such cases (93.0%) was higher than empirical treatment (33.3%) (P < 0.001). After the restriction policy, consumption of antibiotics belonging to the restricted groups was decreased by 44.8%. Total expenditure of all antibiotics was decreased by 18.5%, and the savings were US$332,000 per year. This restriction policy was effective in promoting rational antibiotic prescription and lowering antibiotic cost and consumption in our hospital.

The spectrum of candidiasis has changed with the emergence of non-albicans Candida spp. and acquired antifungal resistance, especially in immunocompromised hosts. This changing scenario has necessitated routine antifungal susceptibility testing. In the present work, 102 Candida spp. isolates gathered during 2003 - 2004 were characterized by standard procedures, and antifungal susceptibility testing to amphotericin B, fluconazole and itraconazole was performed by broth macrodilution (BMD)-minimum inhibitory concentration (MIC) and disk diffusion (DD) methods. Among all isolates, 77.4% were from an ICU and 10.8% were obtained from a nursery. The majority of the isolates were C. tropicalis (48%), followed by C. parapsilosis (27.4%) and C. albicans (22.5%). Overall 6.9, 4.9 and 3.9% of all isolates were resistant to amphotericin B, fluconazole and itraconazole, respectively. Out of the 5 (4.9%) isolates resistant to fluconazole, 4 (3.9%) were from patients with AIDS on fluconazole prophylaxis. A discrepancy was observed between the results of susceptibility testing by DD and those by BMD-MIC: 15 (14.7%) isolates were reported to be resistant by DD despite having low MICs. Based on these results, it was concluded that initial antifungal screening of clinical isolates by the DD method followed by confirmation of resistant strains by the broth dilution method is desirable to optimize patient management.

We investigated the characteristics and detection rates of SEN virus (SENV) infection among 100 Turkish patients who had with high alanine aminotransferase (ALT) and aspartate aminotransferase levels but were negative for HBV DNA and HCV RNA and had no history of transfusion. As a control group, we also analyzed 50 healthy individuals who had normal ALT levels, were negative for HBV DNA and HCV RNA, and had no history of transfusion. The serum samples of patient and controls were analyzed by PCR to detect the presence of SENV DNA and its two genotypes (SENV-H and SENV-D). We detected SENV DNA in 13 of 100 (13%) patients. Five of 13 (38.46%) patients were positive for SENV-D and 8 of 13 (61.53%) patients were positive for SENV-H DNA. We also detected SENV DNA in 5 of 50 (10%) patients in the control group. Two of 5 (40%) patients were positive for SENV-D and 3 of 5 (60%) patients were positive for SENV-H DNA in the control group. SENV was detected at almost the same frequency in the patient and control groups. SENV did not seem to contribute to the pathogenesis of liver disease (P > 0.05) in this cohort. Our results also showed that SENV transmission was not only associated with blood transfusion but also with some other possible routes.

Adhesion to biomaterial is assumed to be a crucial step in the development of staphylococcal foreign body infections. Production of extracellular slime has major implications for the development and implementation of therapeutic strategies. The effect of extracted slime was investigated on the activity of vancomycin, teicoplanin, linezolid, quinupristin/dalfopristin, rifampicin and ranbezolid against 10 clinical and 4 ATCC staphylococcal isolates. The slime extract caused a 2- to 16-fold increase in the MICs of vancomycin and teicoplanin, with a shift in the MIC₉₀ from 2 to 32 (vancomycin) and 2 to 16 (teicoplanin), whereas the MICs of linezolid and quinupristin/dalfopristin were only moderately affected. In time-kill studies, a significant decrease in bacterial killing (>3 log₁₀ cfu/ml) was observed with vancomycin and teicoplanin (4× MIC) after addition of slime (5 and 20 mg/ml), whereas the effect of killing by linezolid and quinupristin/dalfopristin was very modest. The rifampicin and ranbezolid MICs and kill curves were not influenced by the addition of slime. The present study thus indicated that slime interferes with the antimicrobial effect of glycopeptide drugs (vancomycin, teicoplanin), and that for effective prevention and treatment of prosthetic device-related infections, appropriate and newer antibiotics such as ranbezolid should be considered.

In this article, the development of a new TaqMan-based one-step real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay for detection and quantification of Crimean-Congo hemorrhagic fever virus (CCHFV) RNA is described. Selected oligos targeting the highly conserved S region of CCHFV were designed by using our oligo design and analysis software, Oligoware 1.0. None of the primer sequences showed genomic cross-reactivity with other viruses or cells in a BLAST (NCBI) search analysis. The sensitivity and specificity of the primers and the probe were tested using 18 serum samples from patients from East Anatolian who were suspected of having CCHFV, including 2 samples that had already been confirmed to be positive for CCHFV. Among the 16 previously unconfirmed samples, 5 were positive by TaqMan-based one-step real-time RT-PCR and 1 was positive by non-nested RT-PCR, and these results were confirmed with DNA sequencing analysis. The 2 previously confirmed CCHFV RNA samples were also positive by both TaqMan-based one-step real-time RT-PCR and non-nested RT-PCR tests. To ensure the quantitative reproducibility of TaqMan-based one-step real-time RT-PCR, the procedure was repeated several times and the same results were obtained (SD = 0.84 [maximum value]). The developed assay was able to sensitively quantify the concentration of CCHFV RNA, which ranged from 10² to 10⁷ copies/ml per reaction, using plasmid standards generated from the CCHFV RNA (correlation coefficiency = 0.989). The results of the one-step real-time RT-PCR assay were more sensitive than those of the non-nested RT-PCR assay. It can be concluded that our one-step real-time RT-PCR assay is a reliable, reproducible, specific, sensitive and simple tool for the detection and quantification of CCHFV.

Acute suppurative cholangitis is a serious complication of biliary obstructions due to infection. Salmonella enterica serovar Typhi is an important biliary pathogen. Bile samples from 445 patients with biliary diseases as well as those requiring biliary drainage for other miscellaneous gastrointestinal diseases were investigated bacteriologically with special emphasis on Salmonella. Fecal samples or rectal swabs were also obtained from 402 of these patients. Bactericholia was detected in 68.8% patients and Salmonella in 5.8% of all bile samples. Other strains of salmonellae were also present in a fair number of the samples. Some of the patients had the same type of bacterial isolates from their stool samples as those from their bile samples. Colonization of the biliary system may not be clinically apparent, but is associated with an increased risk of infection.

Pyogenic liver abscess (PLA) is a potentially life-threatening disease, and early diagnosis may be difficult. In order to provide diagnostic clues and to enhance the prompt management of such cases, we retrospectively investigated the clinical characteristics of PLA during a 3-year period in a tertiary-care hospital. The crude incidence rate of PLA in our study was 446.1 per 100,000 hospital admissions. Male predominance and a mean age of 57.6 ± 14.4 years were observed. Diabetes mellitus was the most common concomitant disease, and biliary pathologies were the most common predisposing cause of this type of abscess. The most common clinical features were fever, chills, and abdominal pain. Leukocytosis was found in 67.3% of the patients, and the observed C-reactive protein (CRP) values were high. The most common pathogen was Klebsiella pneumoniae. The mortality rate was 6.5%. A complete history, physical examination, evaluation of the white blood cell count and CRP, and the prompt arrangement of imaging studies may lead to an earlier diagnosis. The aggressive performance of image-guided catheter drainage and the appropriate administration of antibiotics may reduce the mortality rate of PLA.

We compared the overall usage of veterinary therapeutic antimicrobials in Japan to the proportion of antimicrobial-resistant. Escherichia coli isolated from the feces of apparently healthy food-producing animals in 2001. The annual sales volume of veterinary antimicrobials, which is published and accumulated information, was subdivided according to the target animal species (cattle, pigs, broiler chickens, and layer chickens). The antimicrobial susceptibility of the isolates was examined against 7 classes of 11 antimicrobials. The rates of antimicrobial resistance among the isolates were found to correlate significantly with the usage of antimicrobial agents in cattle, pigs, and broiler and layer chickens. Therefore, the overall usage of veterinary antimicrobials appears to contribute to the appearance of antimicrobial resistance in E. coli isolates from apparently healthy food-producing animals.

Monoarticular tuberculosis (TB) affecting the knee is rare in all forms of TB (0.1 - 0.3%). We present the case of a patient with tuberculous arthritis in whom the diagnosis was belated due to a lack of familiarity with the disease; here, we emphasize the difficulties associated with the diagnosing joint TB. A 20-year-old man was referred to our department due to swelling of the right knee and the presence of persistent, mild pain for 4 years. The lack of systemic evidence of this disease, the indolent course of disease, and the presence of non-specific symptoms renders early recognition of this disease difficult. Furthermore, in cases in which a diagnosis cannot be reached simply by culturing the synovial fluid, synovial biopsy cultures should be considered in the diagnostic process, due to the high rate of positivity of such cultures. The diagnosis and treatment of articular TB are both urgent matters; surgical debridement and strict adherence to antituberculous chemotherapy tend to yield a satisfactory functional outcome.

We present the case of a 20-year-old male who had a non-traumatic soft tissue lesion (4 × 3 cm) with recurrent discharge at his right posteromedial antebrachial muscles; the patient underwent surgery twice, and antibiotic therapy was administered, but no cure was achieved with these treatments. The patient underwent surgery at our medical center. There was no history of pulmonary, gastrointestinal, or genitourinary tuberculosis (TB). Due to suspected pulmonary, genitourinary, and gastrointestinal TB, radiography and computed tomography scans were performed, and these studies disclosed no evidence of a primary origin. The erythrocyte sedimentation rate and the results of purified protein derivate testing were normal. We also detected submandibular lymphadenopathy (LAP) (2 × 3 cm) localized at a submandibular site in our patient 4 months after his first visit to our clinic. Smears were stained with Ehrlich Ziehl Neelsen (EZN) stain and cultures were grown for Mycobacterium tuberculosis complex (MTC); the samples used for these assays had been obtained by incisional biopsy of the forearm lesion and by aspiration of the submandibular lymph node, and they were found to be MTC-positive. Then, a culture for MTC, derived from an induced sputum sample, was found to be positive, despite the negative results obtained with a sputum smear subjected to EZN staining. According to these results, the primary focus of the tuberculous pyomyositis and the submandibular LAP was the lungs. The lesion and submandibular LAP were both treated successfully by the administration of antituberculous chemotherapy.

In order to invent a screening system to check in vivo gene function and the efficiency of gene transfer mediated by a retroviral vector system, we established a novel packaging cell, PacNIH/A8, based on the neuropathogenic retrovirus A8-V. To construct the expression vector, pA8(Ψ-), which expresses the genes gag, pol and env derived from A8-V, the SV40 early region was used for the polyadenylation signal (polyA signal). When a 0.85 kbp fragment in the SV40 early region was employed for the expression vector (pA8(Ψ-)β), env expression was abolished. This abolition was rescued by shortening the SV40 early region to 0.14 kbp (pA8 (Ψ-)δ). The NHI3T3 cells transfected with pA8(Ψ)δ showed expressions of both env and gag genes.

To evaluate the relation between infectious agents and reproductive health hazards for health care workers (HCWs), a cross-sectional study consisting of 73 HCWs and 65 bureau workers was conducted. The reproductive health problems of both groups were compared using a questionnaire, and serologic examinations for measles, varicella and hepatitis B were performed. There were no differences between the two groups according to the rate of seropositivity of measles and varicella (P > 0.05). The prevalence of anti-HBc seropositivity was significantly higher among HCWs than controls (31.5 versus 16.9%). There were no differences between seropositive and seronegative subgroups of measles, varicella and hepatitis B regarding the rates of normal delivery time, preterm and postterm delivery and stillbirth. Subjects seropositive for anti-HBc showed a higher spontaneous abortion rate than those who were seronegative (38.2 versus 16.3, P = 0.009). Although these data showed that HCWs had a high rate of anti-HBc seropositivity and that the rate of spontaneous abortion was associated with past hepatitis B virus infection, further studies including larger populations are needed. We considered that it should be strongly recommended that all HCWs be vaccinated against this virus, and future studies should be focused on the relationship between infectious diseases and reproductive health problems in HCWs.

Central nervous system (CNS) tuberculosis (TB), the most dangerous form of TB, remains a public health problem, particularly in developing countries. In the differential diagnosis of intracranial tuberculomas (ICTs), images on radiological findings should be differentiated from other causes of space-occupying lesions. These lesions include malignant diseases such as glioma or lymphoma, pyogenic abscess, toxoplasmosis, neurocysticercosis (NC), sarcoidosis, hydatidosis and late syphilitic involvement of CNS. We present a case with multiple ICTs mimicking NC with similar clinical and imaging manifestations in a young immunocompetent patient. The diagnosis was based on brain magnetic resonance imaging findings. The definitive diagnosis was confirmed mycobacteriologically in cerebrospinal fluid and sputum specimens. Adequate response to anti-TB chemotherapy was achieved while multiple ICTs in the brain disappeared slowly. In the absence of appropriate therapy, these pathologies might be fatal; the possibilities of differential diagnosis would be of great clinical importance, particularly because of the different treatment protocols required for the NC and ICTs.

The Susceptible Infected and Recovery (SIR) Model proposed by Robert May in the UK is the basis of the present mathematical model building of infectious disease epidemics. Need for model building incorporating more social and other relevant factors has been recognized. An important example is the introduction of idea of the scale-free distribution of links among the people. More refined models by taking into account the nature of a pathogen, geo-sociological factors, lifestyles of the people, etc., have been developed. For example, Koopman proposed a model for prediction of epidemic expansion based on actual epidemiological data. Eubank proposed a model assessing the bio-terror attack using a model city where every day activity is going on. The present workshop, participated by experts from the US, the UK and Japan, is the first meeting of the proposed series of conference on this issue.

Infection transmission systems circulate infection through complex contact patterns related to both contact patterns and patterns of factors that affect the risk of transmission given contact. The nonlinear dynamics of infection transmission cause these patterns to make big differences in population infection levels. A science of infection transmission system analysis is needed to focus on those details that affect the control of infection transmission. This science must have a strong theoretical base because there is little chance that a dominantly data based approach not using mechanistic models of transmission will have any predictive value. The theoretical base should be built on linked transmission system models that are focused on making needed inferences for both building the theoretical base and making infection control decisions. The linking of different models is needed for a strategy of inference robustness assessment that is designed to find the model that is simple enough to effectively analyze the transmission system but not so simple that realistic violation of simplifying assumptions will change an inference. Types of models that should be used in such linked analyses include deterministic and stochastic compartmental models, discrete individual models with individual event histories but structured mass action mixing, network models that provide more detail as to who has contact with whom, and intermediate model forms such as correlation models that address some aspects of contact details while preserving the flexibility of deterministic compartmental models to structure mixing and analyze the system. While transmission system science is currently weak in regards both to its data base and its theory base, many things are now coming together that could make this science flourish. On the data side these include greater ability to detect infectious agent sequences in the environment and greater ability to sequence and genetically relate agents identified at different sites in the transmission system. On the theory sides, new model construction and model analysis methods are providing new potential to use the new sources of data. Also new parameter estimation methods provide new potential to combine models and data in effective analytic strategies.

It has recently become possible to simulate directly dynamics on very large networks. This paper describes a model of epidemiology on a social network, the Epidemiological Simulation System (EpiSims), and offers general speculation on analyzing disease dynamics on networks. We describe the process of building a realistic social network, describe several different definitions of the network, each useful for certain purposes. Finally, we raise some important questions about structural properties of networks and how they influence dynamics.

We are now planning to make a transmission model of infectious diseases in the scale of a city. People live in the city contacting other persons with daily life. The model regards a contact as a source of infection. A person will be simulated as a simple system of differential equations. As a candidate of differential equations, we are now investigating Marchuk’s simple model. We adopt Marchuk’s simple model because it has formation time, i.e., latent time. As Dr. Takeuchi showed, latent time is very important. There remain problems of choosing parameters for special diseases. We are now planning to use Marquardt method to minimize residuals form clinical data to estimate parameters. As for contacts, there are many approaches. The approach of the MIDAS project is very intensive. Our approach is simple. There are about 30,000 Japanese every fifteen minutes daily life data, sleeping, eating, work, study, house keeping, etc. Our approach is to make virtual families, husband, wife, children in a city and assign actions from the every fifteen minutes data statistically and estimate their contacts in the companies or schools, etc.

Mathematical modeling of infectious disease transmission aims to predict the spread of infection and the effectiveness of containment strategies. For the case of infectious diseases that transmit between human, one key factor becomes the modeling of contacts between individuals through which the disease is potentially transmitted. We review several formulations of such contacts with emphasis on the recently investigated scale-free network, and also discuss the effectiveness of vaccination strategies.

The dependence of the incidence of the hospital infection on the number of the beds was studied by using SIR model with the computer simulation. We obtained the result that the hospital with more beds has a higher probability of experiencing an outbreak. The integration of smaller hospitals into a larger hospital was once considered economically advantageous and such a policy has been implemented in Japan since the early 1980s. This analysis, however, warns against the policy.

HIV infection is exponentially increasing in the past decade among young homosexuals in Japan. Possible influence of social webs among young males whose creation was facilitated by electronic innovation is discussed.