This year 2010 marks the 30th anniversary of smallpox eradication, as declared by the WHO Assembly in 1980. As someone who worked for this program for many years, I would like to present my recollection of how it succeeded and what lessons can be learnt, with the added benefit of hindsight. The program achieved the global unification of mankind despite differences in race, nationality, religion, and politics, and research contributed significantly to building the effective strategy that ultimately led to success. These lessons should be useful in a designing a planning solution for many of the problems we face in today's changing world, including problems regarding health security and even those in current and future socioeconomic regions.
The phenotypic and genotypic characteristics of 6 clinical strains of Vibrio cholerae isolated in Surabaya, Indonesia in 2009 were examined. The DNA fingerprints obtained suggested that these isolates were not from a single clone. Furthermore, all isolates produced cholera toxin and possessed the classical type of toxin B subunit gene, thus meaning that this is the first report of the occurrence of El Tor variants of V. cholerae in Indonesia. Although all isolates were sensitive to almost all antibiotics tested, including ampicillin, chloramphenicol, ciprofloxacin, gentamicin, levofloxacin, kanamycin, nalidixic acid, norfloxacin, streptomycin, trimethoprim–sulfamethoxazole, and tetracycline, and had no mutation in the gyrA and parC genes, they nevertheless possessed the class 1 integron that is a molecular vehicle for the acquisition of antibiotic resistance genes, suggesting that they have the potential to acquire the genetic element for drug resistance.
Enterovirus 71 (EV71) is shown to be a major causative agent in outbreaks of hand, foot, and mouth disease (HFMD) reported in Guangdong (GD) Province of China in 2008. A total of 48,876 HFMD cases (131 severe and 21 fatal) were reported to the GD HFMD web-based surveillance system, which covers 871 clinics. The main causes of death included central nervous system damage, heart failure, and pulmonary edema. The incidence rate was 52 per 100,000, and the epidemic peak appeared in May and June. EV71 was found in 59% and coxsackievirus A16 in 26% of 936 laboratory-confirmed cases. Other viruses are likely to be responsible for the remaining 15% of cases. Of the 185 EV71 cases collected, 62% were mild, 27% were severe, and the remaining 11% were fatal. A total of 17 EV71 isolates were subjected to nucleotide sequencing of the entire VP1 gene. Phylogenetic analysis showed that the GD EV71 strains belonged to the C4 subgenotype and that EV71 circulates at a national rather than a regional level. A Comparison with the VP1 gene from a different clinical case showed that there was no obvious virulence determinant in this locus. Furthermore, this study found that most deaths occurred in rural areas, thereby indicating that delayed diagnosis and incorrect treatment may play an important role.
We have developed a cytolethal distending toxin (cdt) gene-based species-specific multiplex PCR assay for the detection and identification of Campylobacter jejuni, C. coli, and C. fetus. The applicability of this assay was evaluated with 325 Campylobacter strains isolated from diarrheal patients in Japan and the results were compared with those obtained by other genetic methods, including hipO gene detection and 16S rRNA gene sequencing. Of the 325 strains analyzed, 314 and 11 were identified as C. jejuni and C. coli, respectively, by combination of hipO gene detection and 16S rRNA gene sequencing. When the multiplex PCR assay was employed, 309, 310, and 314 strains were identified as C. jejuni on the basis of cdtA, cdtB, and cdtC gene-specific primers, respectively. Similarly, 11, 11, and 10 strains were identified as C. coli on the basis of cdtA, cdtB, and cdtC gene-specific primers, respectively. Sequence analysis of the cdt gene region of 6 strains (5 C. jejuni and 1 C. coli) which did not yield specific PCR products in any of the cdt gene-based multiplex PCR assays revealed deletions or mutations of the cdt genes. Pulsed-field gel electrophoresis indicated that C. jejuni and C. coli strains were genetically diverse. Taken together, these findings suggest that the cdtC gene-based multiplex PCR seems to be a particularly simple and rapid method for differentiating between species of Campylobacter strains, such as C. jejuni and C. coli. However, combination of these multiplex PCR assays will allow more accurate identification.
A total of 156 methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients hospitalized in southern Iran were tested for staphylococcal cassette chromosome mec (SCCmec) types and antibacterial susceptibility patterns between May 2008 and May 2009. Type III SCCmec was the most prevalent (116, 74.3%), followed by mec types A (147 bp only; 11, 7.1%), IVa (8, 5.1%), IVc (7, 4.5%), IVd and V (4, 2.6%), and II (1, 0.6%). Class A mec and type III ccr and mec complexes were also predominant. All isolates were found to be sensitive to vancomycin, teicoplanin, linezolid, quinupristin-dalfopristin, mupirocin, and fusidic acid. However, reduced sensitivity of these MRSA isolates to other antibiotics, including rifampin, co-trimoxazole, clindamycin, cephalexin, tetracycline, ciprofloxacin, erythromycin, and gentamicin, was also observed. The predomination of type III SCCmec could be due to the antibiotic pressure which facilitated its clonal selection and dissemination. The present findings are indicative of the existence of community-acquired types (IV, V) in the hospitals studied, therefore comprehensive and periodic control measures and rational prescription of appropriate antibiotics are highly recommended to reduce antibiotic resistance.
It has been reported recently that oral human papillomavirus (HPV) infection is associated with oropharyngeal squamous cell carcinomas. The aim of this study was to determine the prevalence of HPV infection and HPV types in the oral cavity and cervix of female sex workers in Japan. Oral and cervical swabs were taken from 196 female sex workers who visited a clinic for regular medical checkups in 2007, and genomic DNA was extracted from those specimens. The HPV L1 gene was amplified by polymerase chain reaction (PCR) using original and modified GP5+/6+ primers, and genotyping was performed using the Kurabo GeneSquare Microarray or by sequencing cloned PCR products. HPV DNA was detected in the oral cavity of 12 (6.1%) women, with HPV-56 being the most common type (7/12). Likewise, HPV DNA was detected in the cervix of 103 (52.6%) women, with HPV-52 (30/103, 29.1%), followed by HPV-16 (24.3%) and HPV-56 (18.4%), being the most common. Of the 12 women with oral HPV infection, only two were infected with the concordant HPV genotype in the cervix. These findings suggest that oral HPV infection occurs independently of cervical HPV infection in this population, and that oral HPV infection may play a role in HPV transmission in Japan.
The genetic delivery of therapeutic monoclonal antibodies (mAbs) by in vivo production may offer a new solution to the current problems in the mAb therapy for microbial diseases. Herein, plasmids encoding the neutralizing mAb against hemagglutinin (HA) of A/PR/8/34 influenza virus (IFV) were electro-transferred into mouse muscle and the relationship between serum recombinant anti-HA mAb (rHA mAb) levels and the prophylactic efficacy against lethal IFV infection were analyzed. Pretreatment of the muscle with hyaluronidase before electroporation and gene transfer into 3 muscles resulted in a marked enhancement of the mAb expression. After single gene transfer, peak serum concentrations were reached around 20 days after the gene transfer following sustained expression of >10 µg/ml of rHA mAbs. This level of rHA mAb expression was sufficient to protect all mice against a lethal IFV infection. Furthermore, a significant rHA mAb expression level sufficient to protect the host against lethal IFV infection was maintained for at least 130 days. Passive immune-prophylaxis with gene transfer using the plasmid encoding neutralizing mAbs may therefore provide effective protection against viral infections, including IFV.
Bovine spongiform encephalopathy (BSE) was transmitted to three macaques by intracerebral inoculation of a brain homogenate from affected cattle detected in Japan. All monkeys developed abnormal behavioral signs, such as intermittent anorexia and hyperekplexia, around 24 months after inoculation. Neuronal symptoms, such as tremor, myoclonic jerking, and paralysis, appeared 27–44 months after inoculation. These symptoms worsened and total paralysis ensued within a year after onset. The disease duration was approximately 8–12 months. Both the incubation period and the duration of disease were shortened in the secondary transmission experiment to macaques. Heavy accumulation of disease-causing conformer(s) of prion protein (PrPSc), with a similar glycoform profile to the PrPSc contained in the inoculum, and severe spongiform changes in the histology of the brain, confirmed the successful transmission of BSE to monkeys. Florid plaques, a characteristic histological hallmark of variant Creutzfeldt-Jakob disease, were prominent in the cerebral cortex, in which a prion antigen was detected by immunohistochemistry (IHC). PrPSc was mostly confined to the central nervous system, although small amounts of PrPSc accumulated in the peripheral nerves of monkeys, as detected by Western blotting (WB). Neither IHC nor WB detected PrPSc in the lymphatic organs/tissues, such as the tonsils, spleen, and appendix.
A total of 514 consecutive clinical Escherichia coli isolates, irrespective of resistance background, were collected in the period 2002-2008 in Wenzhou, southern China, to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR). The dominant PMQR gene was aac(6')-Ib-cr, followed by qnr, whereas qepA was absent. A total of 253 (49.2%) of these isolates were aac(6')-Ib-positive. Subsequently, 134 of these isolates were sequenced and 42 (31.3%) found to harbor aac(6')-Ib-cr, 18 to harbor new aac(6')-Ib mutants, and 74 to harbor wild-type aac(6')-Ib. The genes qnrA, qnrB, and qnrS were found in 2 (0.4%), 6 (1.2%), and 14 (2.7%) of 514 isolates, respectively, with 2 isolates co-harboring qnrB and qnrS genes. Sequencing allowed us to identify qnrA1, qnrB4, qnrB6, and qnrS1 in 20 qnr-positive isolates, with qnrS1 being the most prevalent allele. The genes qnrC and qnrD were not found in any isolates. Interestingly, 35% of qnr-positive isolates and 16.7% of aac(6')-Ib-cr-positive isolates were susceptible to ciprofloxacin. PMQR genes are therefore present in both quinolone-resistant and -susceptible isolates and can also be transferred by conjugation experiments, thus suggesting a likely future increase in quinolone resistance.
Panton-Valentine leukocidin (PVL) is a cytotoxin which causes leukocyte destruction and tissue necrosis. Although it is produced by fewer than 5% of Staphylococcus aureus strains, PVL-producing S. aureus is emerging as a serious problem worldwide. There has been a marked increase in the incidence of necrotizing lung infections with a very high mortality associated with these strains. This report describes a fatal case of hospital-acquired necrotizing pneumonia caused by PVL-positive methicillin-susceptible S. aureus in a patient with a brain tumor.
Herein we present a case of Neisseria meningitidis-related sepsis and meningitis in a 60-year-old woman. The N. meningitidis strain was identified as serogroup B and sequence type (ST)-4893 by multilocus sequence typing (MLST). The patient in this case had visited France prior to development of symptoms. No meningococcal isolate belonging to ST-4893 has been identified in Japan previously, whereas an ST-4893 strain from France has been reported in the MLST database. These results strongly suggest that this case is likely to have been imported from France.
A total of 18 strains of EHEC O157:H7 were isolated from distinct cases in Akita Prefecture, Japan from July to September 2007. The genetic relatedness of these isolates was investigated by performing a multilocus variable number of tandem repeats analysis (MLVA) and a pulsed-field gel electrophoresis (PFGE) analysis using XbaI. The PFGE analyses allowed us to group these 18 isolates into three major clusters. The MLVA results correlated closely with those obtained by PFGE, although some variants were found within the clusters obtained by PFGE, thus highlighting the utility of this technique for determining a precise classification when it is difficult to differentiate between isolates with indistinguishable or very similar PFGE patterns. In addition, MLVA is a much easier and more rapid method than PFGE for analysis of the genetic relatedness of strains. Thus, as a second molecular epidemiological subtyping method, MLVA is useful for the regional outbreak surveillance of EHEC O157:H7 infections.
The aim of this study was to determine the capsular types of Haemophilus influenzae isolated from clinical specimens by slide agglutination serotyping (SAST) and PCR capsule typing methods. All the isolates were biotyped and their antibiotic resistance patterns also determined. Thirteen isolates of serotype b, 2 of serotype e, 4 of serotype f, and 19 nontypeable (NT) isolates were identified by SAST method in 38 H. influenzae culture-positive samples. Capsule typing by PCR increased the proportion of all invasive cases from 34.2% (by SAST) to 60.5%, and 6 culture-negative samples were identified as invasive H. influenzae (Hib) by this method. The discrepancy rate between SAST and PCR results were 41%. Biotypes I, II, and III were the prevalent biotypes whereas biotypes VI and VII were not found. The majority of capsule type b belonged to biotype II. The isolates were resistant to cotrimoxazole (47.1%) and ampicillin (43.6%). Multidrug resistance was observed in 7 of the isolates.
Metallo-beta-lactamase (MBL)-producing Acinetobacter baumannii has become a growing therapeutic concern worldwide. The aims of this study were to evaluate the antimicrobial susceptibility of A. baumannii isolates and to determine the prevalence of MBL genes among carbapenem non-susceptible isolates. During a period of 16 months (March 2008-June 2009), 100 isolates of A. baumannii were collected from different clinical specimens of inpatients admitted to the largest teaching hospital in the northwest of Iran. All isolates were tested for antimicrobial susceptibility by Kirby-Bauer disk diffusion method. Carbapenem non-susceptible isolates were further screened for production of MBL by Etest and were then subjected to PCR for detection of MBL genes of types blaIMP and blaVIM. Among 63 carbapenem (imipenem and meropenem) non-susceptible isolates of A. baumannii, 31 (49%) were found to be MBL producers. Of 31 MBL-producing isolates, 19 (61%) carried the blaIMP gene and 9 (29%) carried the blaVIM gene. All MBL-producing isolates were multidrug resistant. This is the first report of IMP and VIM types among MBL-producing A. baumannii in Iran.
A cross-sectional study was undertaken to determine the current prevalence of leptospirosis and hantaviral infections, and the socio-demographic characteristics and risk factors of infected patients, in Kandy, Sri Lanka. This report discusses the serological evidence of hantavirus infections among 105 suspected leptospirosis patients, 8 of whom had hantavirus antibodies. Serotyping ELISA showed that these 8 patients had high optical density values for Thailand virus. Most of the sera showed that the focus reduction neutralization test titer against Thailand virus was higher than that against Seoul virus, thereby suggesting that the hantaviral antibodies found in Sri Lanka are different from Seoul virus but closely related to Thailand virus. These findings imply that the hantaviral infection found in Kandy, Sri Lanka appears to be due to a virus similar to Thailand virus. Epidemiological analysis revealed that the association between hantavirus infection and socio-demographic characteristics was not statistically significant.
The aim of this study was to determine the influence of menstruation on the bacterial population of healthy Japanese women's vulvas, especially the labia minora. Labia minora swabs were obtained from 10 premenopausal, nonpregnant Japanese women at premenstruation and on day 2 of menstruation. Vaginal swabs were also obtained from 3 out of the 10 women. No significant difference was found in the average bacterial cell count between the menstruation and premenstruation samples. Molecular analysis using a 16S rRNA gene-based clone library method detected 22 genera from the labia minora swabs (total 20), with the genus Lactobacillus being predominant at both premenstruation and during menstruation in 7 out of the 10 women. Of the other 3 women, 2 showed various kinds of bacterial species, including oral and fecal bacteria, with Atopobium vaginae and Gardnerella vaginalis predominating in the remaining woman's vulva in both conditions. In total, 6 out of 10 cases (60%) showed significantly different microbiota of the labia minora between the two conditions. These results imply that menstruation may promote a distortion of the bacterial flora around the vulva, although it causes no significant increase of the bacterial count.
A low molecular weight type of atypical bovine spongiform encephalopathy (L-BSE) was transmitted to two cynomolgus macaques by intracerebral inoculation of a brain homogenate of cattle with atypical BSE detected in Japan. They developed neurological signs and symptoms at 19 or 20 months post-inoculation and were euthanized 6 months after the onset of total paralysis. Both the incubation period and duration of the disease were shorter than those for experimental transmission of classical BSE (C-BSE) into macaques. Although the clinical manifestations, such as tremor, myoclonic jerking, and paralysis, were similar to those induced upon C-BSE transmission, no premonitory symptoms, such as hyperekplexia and depression, were evident. Most of the abnormal prion protein (PrPSc) was confined to the tissues of the central nervous system, as determined by immunohistochemistry and Western blotting. The PrPSc glycoform that accumulated in the monkey brain showed a similar profile to that of L-BSE and consistent with that in the cattle brain used as the inoculant. PrPSc staining in the cerebral cortex showed a diffuse synaptic pattern by immunohistochemistry, whereas it accumulated as fine and coarse granules and/or small plaques in the cerebellar cortex and brain stem. Severe spongiosis spread widely in the cerebral cortex, whereas florid plaques, a hallmark of variant Creutzfeldt-Jakob disease in humans, were observed in macaques inoculated with C-BSE but not in those inoculated with L-BSE.