Worldwide, tuberculosis remains the most frequent and important infectious disease to cause morbidity and death. However, the development of new drugs for the treatment and prophylaxis of TB has been slow.Therefore, novel types of antituberculous drugs, which act on the unique drug targets in Mycobacterium tuberculosis, particularly the drug targts related to the establishment of mycobacterial dormancy and persistency in host macrophages, are urgently needed. In this context, it should be noted that current antituberculous drugs mostly target the metabolic reactions and proteins which are essential for the growth of M.tuberculosis in extracellular milieus. It may also be promising to develop another type of drug that exhibits an inhibitory action against bacterial virulence factors which cross-talk and interfere with signaling pathways of M.tuberculosis-infected host immunocompetent cells such as macrophages and T cells, thereby changing the intracelluar milieus favorable to intramacrophage survival and growth of infected bacilli. In this review article, I will describe recent approaches to identify and establish novel potential drug targets in M.tuberculosis, especially those related to mycobacterial virulence factors interfering with host cytokine networks, particularly those acting upon intracellular signaling pathways of macrophages.
Several Japanese companies sell electrical devices advertised as effective in inactivating viruses and killing bacteria by releasing special materials, e.g., Plasmacluster ions, Nanoe particle and minus ions, into the air. These companies claim that their devices killed bacteria on plates in their own experiments. We tested device effectiveness using the same experiments from the Plasmacluster ioniser SHARP Co.,Japan, the Nanoe generator Panasonic Co., Japan, and the Vion KING JIM Co., Japan, to test their advertising claims. Bactericidal ability on agar plate was tested, using Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, and Enterococcus faecalis as follows : the medium containing a certain amount of each bacterium was put onto an agar plate and smeared. Plates were kept in a closed chamber (inner volume 14.4m3) ora glove box (inner volume 0.2m3), with one of the devices run for 2 hours. Plates not exposed to any device were used as controls. Each plate was retrieved and put in an incubator to count the number of bacterial colonies formed on the plate. There was no significant difference in the number of colonies on plates exposed to devices compared to control, in the number for all devices, or in all bacteria tested in experiments in the 14.4m3 chamber. These results strongly suggest that these devices have almost no bactericidal effect, at least in space exceeding this volume. Colony formation was suppressed in the glove box in all devices and in all bacteria tested except P. aeruginosa, although the degree of suppression differed among experiments. The colony formation suppression mechanism was analyzed, and indicated that : colony formation did not change even after the removal of Plasmacluster ions, Nanoe particles, or negative ions from the air, while colony formation was decreased drastically by the removal of ozone from space, which was revealed to be generated inevitably during device operation. These results strongly suggest that the bactericidal effect seen only on the agar plate in narrow space was explained by ozone released in space as a by-product, not by special materials as advertising claimed. It is thus important to analyze the effect of special materials such as those done in this study and to suggest the involvement of ozone as the true cause, as have been done in this study, in evaluating bactericidal effect or viral inactivation as advertised by these companies.
We isolated three strains of vancomycin intermediate Staphylococcus aureus （VISA） from a blood sample of a patient with infective endocarditis （VISA-1）, postoperative pneumonia sputum （VISA-2）, and pyogenic spondylitis blood sample （VISA-3）. These VISA strains did not carry vanA, vanB, vanC1, or vanC2/C3 genes. Cell wall thickening was observed. VISA-1 and VISA-3 PFGE patterns showed the completely same pattern compared to the PFGE pattern of methicillin-resistant Staphylococcus aureus first isolated from patients 1 and 3. After 10 days on brain heart infusion agar, wall thickening in all three type of VISA was unchanged, but VISA-2 and VISA-3 reversed vancomycin susceptibility. The most suitable use of vancomycin in patients with MRSA infection thus appears to be in reducing the opportunity for cell wall thickening.
Mixed human feces were evaluated for simultaneous direct PCR detection of 3 food-borne bacteria verotoxin-producing bacteria, Salmonella,andShigella. Mixed feces concentrated approximately 2.5％ in distilled water, were heated at 95℃ for 5min. The heated suspension was then centrifuged and 5μL of the supernatant poured into a 45μL PCR mixture prepared to neutralize PCR inhibitors originating in biological samples. As a result of PCR under the above conditions followed by melting curve analysis（MCA）, one positive fecal sample containing food-borne bacteria was detected from among 50 mixed fecal samples, showing the same sensitivity as individual cultivation. Results thus indicate that this method enables rapid, reliable, highly sensitive testing of many fecal samples -especially those of personnel handling food, which requires the simultaneous testing of many samples.
Recently available varicella vaccine titers are several dozen times higher than the formulation standard in accompanying information, i.e., ≧1,000PFU/dose. We investigated changes in immunogenicity associated with vaccination using a reduced dose whose virus titer was close to that used when the vaccine was developed, and examined the need for the virus titer presently used. In a non blinded study of 43 children with no history of varicella infection, we administered 0.1mL of varicella vaccine （1/5 of the normal dose） to 20 children 1 year 0 month to 4 years 5 months old （median : 1 year 5 months） and the standard 0.5mL dose to 23 children 1 year 2 months to 3 years 7 months old （median : 1 year 9 months）. We measured IAHA and gpELISA antibody titer before vaccination and 4 to 6 weeks after vaccination. We defined “positive” as ≧2 fold of IAHA titer and ≧50U of gpELISA antibody titer. We administered an additional 0.5mL of varicella vaccine to children whose IAHA titer failed to show seroconversion and remeasured antibody titer 4 to 6 weeks after revaccination. IAHA seroconversion was 25.0％ （5/20） and gpELISA seroconversion 55.0％ （11/20） in the 0.1mL vaccination group, which was lower than that of 76.2％ （16/21） and 87.0％ （20/23）, IAHA p＜0.01, gpELISA p＜0.05, in the 0.5mL vaccination group. We administered an additional vaccination to 19 children―15 in the 0.1mL vaccination group and 4 in the 0.5mL vaccination group―with 100％ seroconversion for both methods. Mean antibody titer after revaccination in the 0.1mL vaccination group （IAHA 26.0, gpELISA 103.7） was higher than those in the 0.5mL vaccination group who seroconverted following initial vaccination （IAHA 24.5,gpELISA 102.6） （p＜0.01）. We also measured virus titer in the remaining vaccine following vaccination of 0.1 mL（n＝20）, and estimated virus titer administered to the 0.1mL vaccination group to be 2,600 - 6,400PFU/dose. Varicella vaccine immunogenicity decreased if dosage was reduced to 1/5 of the standard dose, indicating that the present virus titer is necessary to maintain adequate immunogenicity. An additional administration of the standard dose to children who failed to seroconvert after initial 0.1mL administration produced high antibody titers thought to constitute a booster effect.
We detected and isolated human metapneumovirus (HMPV) and isolated another respiratory virus in pharyngeal swab specimens from 502 pediatric patients with acute respiratory infection, seen at 3 Kyoto City sentinel hospitals from January to December 2011. Our prospective study detected 43 positive HMPV cases (8.6％). Phylogenetic analysis showed that subgroup A2 was most common, followed by B1 and B2,and that A1 was not detected. HMPV was detected mostly in specimens from patients less than 3 years old, and positive HMPV was identified most in spring, peaking in March. Our clinical study showed that positive HMPV patients had fever above 38 degrees (86％) and cough (65％). Among the 30 whose chest radiography was examined, radiological findings were recognized in 18 cases. We found inflammatory infiltrative shadows around the bronchus and peribronchus near the hilum of the lung. Lobar pneumonia and diffuse infiltrative shadows coinciding with peripheral alveolar involvement were not recognized. No difference affecting illness severity was seen among subgroups, viral isolation results, or mixed coxsackie virus or influenza virus infection. In hospitalization, mean disease lasted significantly longer in those with lower respiratory tract symptoms at first examination than in those without such symptoms. We detected HMPV RNA in pharyngeal swabs and stool specimens from patients admitted to the hospital for rhabdomyolysis.
Coinfection with human immunodeficiency virus （HIV） and hepatitis B virus （HBV） is common world wide. The current guidelines for the treatment of HIV infection recommend that HIV patients coinfected with HBV receive antiretoroviral therapy （ART） with two nucleoside analogs against HBV. However, an increase in liver enzymes that is usually attributed to HBV immune reconstitution inflammatory syndrome （IRIS） sometimes occurs in HBV/HIV-coinfected patients after the commencement of ART. We report a case of HBV/HIV-coinfection in which the chronic hepatitis B was successfully treated using interferon （IFN） therapy followed by ART without the development of IRIS. A Japanese man in thirties was referred to our hospital because of an acute HIV infection two months after the diagnosis of an acute HBV infection, which had progressed to a chronic HBV infection. The laboratory test results were as follows : hepatitis B surface antigen （HBsAg） positive, hepatitis B e antigen（HBeAg） positive, HBV DNA level of 8.8 Log copies/mL, HBV genotype A, alanine aminotransferase of 834IU/L, HIV RNA level of 5 Log copies/mL, and a CD4＋T cell count of 437/μL. The initial treatment was natural IFNα therapy for chronic hepatitis B, and HBeAg seroclearance was achieved 20 weeks after the start of therapy. Four months after the end of IFN therapy for 24 weeks, ART including tenofovir and emtricitabine against HBV was commenced. Six months after starting ART, the patientʼs serum HBV DNA level had decreased and become undetectable and HBsAg seroclearance was achieved without an elevation in liver enzymes. The present case suggests that IFN therapy prior to ART contributes to a successful outcome for chronic hepatitis B patients coinfected with HIV, if the HIV status does not require the immediate start of ART.
We report a case with an atypical presentation of descending necrotizing mediastinitis （DNM）. A 47- year-old woman with a medical history of untreated type 2 diabetes mellitus and influenza type A virus infection 2 weeks prior to admission was referred to our hospital complaining of right cervical pain and right upper limb swelling. A chest enhanced computed tomographic （CT） scan showed a ring-enhanced mass-like shadow extending from the right sternomastoid muscle down to the right upper mediastinum, compressing the right subclavicular vein. We diagnosed the patient as having DNM based on a physical examination and the CT findings. Because the abscess extended from deep in the neck to the upper mediastinum and right upper pleural space, emergent abscess debridement and drainage was required. After hospitalization, antibiotics （Ampicillin/Sulbactam 12g/day） were also administered based on Gram-stain findings from the drainage fluid, which showed Gram-positive cocci resembling a string of beads. A culture of the drainage fluid identified Streptococcus agalactiae. Aggressive abscess drainage and early antibiotic therapy resulted in a favorable response. She was discharged without complications on the 33rd hospital day. DNM is well known as a rare but lethal disease. In this case, the presence of diabetes mellitus and post-influenza infection might have been risk factors for a serious S. agalactiae infection. Early aggressive therapy and adequate drainage are recommended for patients with DNM.
We present a case of amebic colitis and liver abscess complicated by acute myeloid leukemia （AML） with high serum procalcitonin （PCT）. A 61-year-old Japanese man seen at our hospital for severe diarrhea and high fever was found to have multiple ulcers in the transverse and sigmoid colon and rectum by colonoscopy and biopsies were conducted. Immature leukocytes with mild anemia and thrombocytopenia were seen in peripheral blood, necessitating bone marrow aspiration and biopsy that yielded a diagnosis of AML （FAB M4Eo）. Serum C-reactive protein and PCT were extremely elevated. Blood cultures for bacteria and fungi were negative. Multiple low-density areas in the liver were found in abdominal computed tomography. Histological colon biopsy findings revealed amebic colitis, strongly suggesting amebic liver abscess. Metronidazole treatment was initiated for amebiasis and subsequent standard chemotherapy for AML was followed after fever was lowered. Hematological and cytogenetic CR was maintained with good clinical condition. Few case reports have been published in Japan to date on amebic colitis and liver abscess complicated by AML and no reports have been made on PCT elevation caused by amebiasis. In conclusion, differential diagnosis of amebiasis is necessary in addition to that of bacterial or fungal infection in serum PCT elevation.
A 76-year-old woman undergoing hemodialysis and having a permanent pacemaker during care elsewhere developed a shunt infection with methicillin-resistant Staphylococcus aureus （MRSA）bacteremia. Vancomycin （VCM） and other antimicrobial agents were not effective even after her artificial shunt vessel was removed. Linezolid （LZD） was administered for 56 days to resolve fever. MRSA was detected repeatedly in blood culture for 7 months except while LZD was being administered, so she was referred to our hospital for further investigation and treatment. Blood culture isolated 3 MRSA strains, all having a minimum inhibitory concentration （MIC） of LZD above 16μg/mL, while that of VCM varied at 2-4μg/mL. Based on these findings, combined VCM, rifampicin, and arbekacin therapy was started but did not resolve the MRSA bacteremia problem. Transesophageal echocardiography showed flat vegetation around the pacemaker lead passing through the tricuspid valve. Based on strongly suspected pacemaker-lead infection, the pacemaker system was removed by heart surgeons using radiographic imaging on day 16 after admission. Her blood culture then became negative. She was returned to the previous hospital on day 66 after admission, where combination antibiotic therapy was continued for about one month. MRSA was not detected again after pacemaker system removal.