The whole-genome sequence analysis of Mycobacterium leprae, which was completed in 2001, revealed the characteristics of this microbe's genomic structure. Half of the M. leprae genome consists of a limited number of protein-coding genes and the rest comprises non-coding regions and pseudogenes. We performed membrane array and tiling array analyses to analyze the gene-expression profile of the M. leprae genome and found that pseudogenes and non-coding regions were expressed similarly to coding regions at the RNA level. The RNA expressions were confirmed by real-time PCR analysis. Expression of these RNAs in clinical samples showed varying patterns among patients, thus indicating that the analysis of RNA expression patterns, including non-coding regions and pseudogenes, may be useful for understanding the pathological state, prognosis, and assessment of therapeutic progress in leprosy.
We performed the genotyping and phylogenetic analysis of respiratory syncytial virus (RSV) isolated from 17 infants with bronchiolitis in Kanagawa Prefecture, Japan in 2005 and 2006. The major genes in these samples (attachment [G] glycoprotein gene, fusion [F] protein gene, and nucleoprotein [N] gene) were sequenced and analyzed genetically. Phylogenetic analysis of these genes revealed that 7 and 10 strains could be classified into subgroups A and B, respectively. Phylogenetic analysis of the G gene revealed that the subgroup A and B strains were unique genotypes GA2 and BA, respectively. Moreover, the amino acid sequences for these genotypes suggested a relatively high frequency of amino acid substitutions in the G and F proteins in these strains, whereas the N protein was highly homologous. These results suggest that RSV genotypes GA2 and BA may be associated with bronchiolitis in the cases studied here.
A laboratory colony of the mosquito Aedes japonicus japonicus, which has recently invaded the United States and is recognized as a highly competent vector of West Nile virus, was established from larvae collected in Narita, Japan. The mosquitoes were maintained with induced insemination, blood-feeding on humans, and oviposition in water provided from the original collection site during the first few generations, then the colony was transferred to a large cage (40 × 40 × 100 cm in height) and adapted to conditions in which specimens were allowed to mate freely. White mice were provided as the blood source, and deionized water was available for oviposition. Approximately 185 eggs, most of which were tolerant to desiccation for at least 1 month, with some surviving for up to 2.5 months, were obtained per female following a single blood-feeding. The rate of successful emergence was nearly 90%, although this rate decreased significantly at high larval densities. The colony has been maintained for 5 years, and developmental profiles of the species have been obtained during that time.
A molecular epidemiological study of rotavirus (RV) and norovirus (NoV) infections was carried out in Nha Trang city in Vietnam between December 2005 and June 2006. RV and NoV were detected in 87 (47.5%) and 12 (6.6%) of the 183 fecal specimens from children hospitalized with acute gastroenteritis, respectively. The majority of patients with RV and NoV were children younger than 2 years of age. The most frequent RV genotypes detected were G3 (n=37, 42.5%) and G1 (n=28, 32.2%) for G type, P (n=61, 70.1%) for P type, and G3P (n=33, 38.0%) and G1P (n=18, 20.7%) for the G and P genotype combination. GII.12 was the most common genotype (6/12, 50%) for NoV, followed by GII.4 (4/12, 33.3%), and we also identified a rare type (GII.19). The results of this study highlight the increased incidence of G3P and the presence of many OP354-like P RVs, as well as the GII.4 2003 Asia variant of NoVs. Furthremore, the first case of GII.19 of NoV in Vietnam is reported.
Mexico is a country with sporadic leprosy cases, and the reemergence of drug resistance is a concern. In this study, molecular analysis of Mycobacterium leprae was employed to clarify the spread of drug-resistant leprosy. Thus, drug resistance-determining regions in the folP1, rpoB, and gyrA genes, which are associated with resistance to dapsone, rifampicin, and ofloxacin, respectively, were analyzed by direct sequencing of the PCR product. No mutations in the folP1 gene were observed in any of the 72 slit skin samples obtained from 38 patients, although two samples carrying a mutation at codon 425 in the rpoB gene, which confers resistance to rifampicin, a key component of multidrug therapy, were identified. In addition, a mutation at codon 91 in the gyrA gene, which correlates with ofloxacin resistance, was found in one sample. These results demonstrate the existence of rifampicin- and ofloxacin-resistant leprosy. Interestingly, wild-type and mutant sequences in the gyrA gene were found to coexist in one clinical sample. In addition, all three drug resistance-related mutations were found in only one of the two earlobes of the patients concerned, suggesting a possible pathway for the spread of drug-resistant M. leprae.
Salmonella enterica has become progressively resistant to antimicrobial agents worldwide as a result of genes carried on different classes of integrons. The aim of the current study was to investigate the molecular diversity of these integrons and their association with antimicrobial resistance in clinical S. enterica isolates from Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Integrons were detected in 65 (47.1%) strains, with classes 1 and 2 being observed in 54 (39%) and 11 (8%) strains, respectively. Integron-positive isolates belonged to seven different S. enterica serovars, and all showed a multidrug-resistant (MDR) phenotype. Our findings show that integrons are widely disseminated among S. enterica strains from Tehran. Furthermore, the results that class 1 integrons were more prevalent than class 2 in Salmonella isolates, and that a statistical association with MDR patterns was observed, suggest that they are more likely to be important in conferring a resistant phenotype to Salmonella strains.
We report the surveillance findings of hand, foot, and mouth disease (HFMD) collected from a general practitioner-based sentinel surveillance system and outbreaks reported by institutions and a laboratory-based enterovirus surveillance system in Hong Kong from 2001 to 2009. A seasonal peak was detected in the warmer months (May–July), along with a smaller winter peak (October–December) from 2006 onwards. The number of older children (>5 years) infected increased from 25.4% in 2001 to 33.0% in 2009 (P=0.01, Mantel-Haenszel chi-square test). Laboratory surveillance detected a cyclical high enterovirus 71 activity every 3 to 4 years. This activity was associated with a higher average hospitalization rate for HFMD patients in the outbreaks reported in the corresponding year, although the difference was only marginally significant (P=0.09, linear regression test). The changing epidemiology of HFMD warrants continuous surveillance in order to guide preventive public-health actions.
Periodontitis is a chronic inflammatory disease caused by the infection of periodontopathic bacteria in dental plaque. However, an individual's susceptibility to this disease appears to be associated with multiple genetic factors, as seen in the case of leprosy. In order to gain a better understanding of the pathophysiology of periodontal disease in subjects with leprosy, we investigated the clinical features of periodontitis and the immunological responses against periodontopathic bacteria in 382 subjects with a history of leprosy and 451 age-matched control subjects. The prevalence of periodontitis and the degree of periodontal pocket depth were found to be significantly higher in leprosy patients than in age-matched controls. Furthermore, a comparison of the clinical parameters of lepromatous leprosy (L-lep) and tuberculoid leprosy (T-lep) patients showed that the probing pocket depth of L-lep patients with periodontal disease was significantly higher than that for T-lep patients. In contrast, serum IgG titers against Porphyromonas gingivalis in L-lep patients were significantly lower than in T-lep patients. These results imply that L-lep patients show more severe periodontal disease than T-lep patients or age-matched control subjects, and that low humoral immunity against P. gingivalis might be one of the genetic factors determining periodontal disease susceptibility in leprosy patients.
The diagnosis of active and latent tuberculosis infection (LTBI) remains a challenge, especially in light of the fact that the tuberculin skin test (TST), which has been used to diagnose LTBI for over a century, has many well-known drawbacks. This study aimed to compare the diagnostic performance of the T-cell-based interferon-gamma releasing assay (IGRA) T-SPOT.TB with the TST for the diagnosis of LTBI in an intermediate tuberculosis (TB)-burden country with high BCG coverage. For this purpose, a total of 91 participants, including culture-confirmed TB patients, healthy contacts known to have been exposed to Mycobacterium tuberculosis, and healthy volunteers, selected from a BCG-vaccinated population were recruited. The sensitivities of theT-SPOT.TB and TST were 79.3 and 25.8%, and the specificities were 75.9 and 56.7%, respectively. The negative- and positive-predictive values for T-SPOT.TB and TST were 78.6 and 76.7% and 42.5 and 38.1%, respectively. The diagnostic performance of the TST in LTBI diagnosis is therefore severely diminished in BCG-vaccinated populations, with the sensitivity and specificity of the T-SPOT.TB assay being markedly higher. IGRAs have been reported to have higher diagnostic sensitivity and specificity in low TB-incidence settings than those seen here. Further larger scale studies in high and intermediate TB-incidence settings are therefore warranted.
The seroprevalence of syphilis in students from a tertiary institution in Benin City, Nigeria was investigated. Venous blood samples (5 mL) were collected from 214 apparently healthy students aged 19–38 years (118 males and 96 females) between February 2009 and October 2009 and the serostatus of syphilis determined qualitatively using the rapid plasma reagin test. Seropositive sera were confirmed using the Treponema pallidum hemagglutination test. The total seropositivity for syphilis was 15.42%, with a prevalence in males and females of 18.64 and 11.46%, respectively. This difference was statistically significant (P<0.05). The highest prevalence was found for the 24–28-year-old age group, while the lowest prevalence was found for the 19–23-year-old age group, where no female tested positive. The results of this study show that the prevalence of syphilis infection among students in Benin City was high and is a public health concern. All persons, including voluntary blood donors, patients with sexually transmitted diseases, or those attending for routine medical checkups, should therefore be thoroughly screenced for syphilis infection.
The relationship between the presence and types of integrons and the antimicrobial susceptibility patterns of Acinetobacter baumannii was investigated. A total of 134 non-duplicated A. baumannii isolates, 54.5% (n=73) of which were subsequently found to carry class 1 integrons, were collected from a regional hospital in Taiwan between March and September 2007. Only two types of gene cassette array, aacA4-catB8-aadA1 and aacC1-orfP-orfP-orfQ-aadA1, were identified. Susceptibility data showed that those strains carrying integrons were significantly more resistant to all antibiotics tested except ampicillin/sulbactam and imipenem. An epidemiological study revealed that the same integron could be found in different unrelated strains. These findings suggest that the presence of integrons in A. baumannii is responsible for both the horizontal transfer of antibiotic-resistance genes related to aminoglycosides and chloramphenicol and also represents a marker of multidrug resistance and epidemic potential.
Ochrobactrum anthropi is an emerging pathogen in immunocompromised patients, with the majority of human cases being central venous catheter-related infections. In contrast, O. anthropi-related biliary sepsis is much rare. Herein we report the clinical and microbiological characteristics of O. anthropi-related biliary sepsis in order to increase awareness of the potential role of O. anthropi in this infection. Further extensive epidemiologic studies should be carried out to ascertain the etiologic association between O. anthropi and biliary sepsis and to identify potential hosts and routes of transmission.
Human ascariasis is caused by infection with the common roundworm Ascaris lumbricoides, although the pig roundworm Ascaris suum has also been reported to infect humans and develop into the adult stage. To elucidate whether pig-derived Ascaris infects humans in Japan, 9 Ascaris isolates obtained from Japanese patients and a further 9 Ascaris isolates of pig origin were analyzed to determine their internal transcribed spacer-1 sequences. Six of the 9 clinical isolates showed the Ascaris genotype which predominantly infects humans in endemic countries, while the other 3 clinical isolates and 9 pig-derived isolates showed the genotype predominant in pigs worldwide. These results suggest that at least some cases of human ascariasis in Japan are a result of infection with pig-derived Ascaris.