A retrospective study on imported hepatitis E in Japan.

Hepatitis E virus (HEV), a causative agent of human hepatitis E, is transmitted through an oral-fecal route, often by contaminated drinking water. Serum specimens were collected from 112 non-A, -B, and -C acute hepatitis patients from 1989 to 2004 in Japan. Of these, 24 patients were found to be positive for anti-HEV IgM and diagnosed with acute Hepatitis E. Seventeen of these patients had a clear history of traveling abroad before disease onset and were counted as cases of imported HEV infection. HEV RNA was detected in 16 of these imported cases, and the nucleotide sequences similar to those of HEV detected in India, Bangladesh, and China were identified. By phylogenetic analysis, the remaining imported case appeared to have been imported from India, even though the patient's travel history was uncertain. These results indicated that some sporadic cases of hepatitis E in Japan are caused by imported HEV, and that phylogenetic analyses enable us to identify the country or area where a patient has been infected.

Selection of Mycoplasma genitalium strains harbouring macrolide resistance-associated 23S rRNA mutations by treatment with a single 1 g dose of azithromycin.

OBJECTIVE: A single 1 g dose regimen of azithromycin has been recommended for the treatment of Mycoplasma genitalium infections. The authors evaluated whether this regimen could select M genitalium strains with macrolide resistance after treatment for M genitalium-positive non-gonococcal urethritis. METHODS: In seven men with non-gonococcal urethritis, who were infected with M genitalium without macrolide resistance-associated mutations but experienced microbiological azithromycin treatment failure, M genitalium DNAs in their post-treatment urine specimens were examined for mutations in the 23S rRNA gene and the ribosomal protein genes of L4 and L22. To assess the relatedness of M genitalium strains before and after treatment, their DNAs in pretreatment and post-treatment urine were genotyped by analysing short tandem repeats of an AGT/AAT unit in the MG309 gene and single nucleotide polymorphisms in the MG191 gene. RESULTS: In four of seven patients, M genitalium in post-treatment urine had an A-to-G transition at nucleotide position 2071 or 2072, corresponding to 2058 or 2059 in the 23S rRNA gene of Escherichia coli. In one of the four strains, Pro81Ser in the ribosomal protein L4 accompanied the mutation in the 23S rRNA gene. The genotyping of M genitalium DNAs suggested that these four post-treatment strains were selected from the respective closely related or identical pretreatment strains without macrolide resistance-associated mutations by the treatment. CONCLUSIONS: The single 1 g dose treatment of azithromycin could select M genitalium strains harbouring macrolide resistance-associated mutations. For M genitalium, this regimen might increase the risk of macrolide resistance selection after treatment.

Recombination analysis of intermediate human adenovirus type 53 in Japan by complete genome sequence.

Human adenovirus type 53 (HAdV-53) has commonly been detected in samples from epidemic keratoconjunctivitis (EKC) patients in Japan since 1996. HAdV-53 is an intermediate virus, containing hexon-chimeric, penton base and fiber structures similar to HAdV-22 and -37, HAdV-37 and HAdV-8, respectively. HAdV-53-like intermediate strains were first isolated from EKC samples in Japan in the 1980s. Here, the complete genome sequences of three such HAdV-53-like intermediate strains (870006C, 880249C and 890357C) and four HAdV-53 strains were determined, and their relationships were analysed. The seven HAdV strains were classified into three groups, 870006C/880249C, 890357C and the four HAdV-53 strains, on the basis of phylogenetic analyses of the partial and complete genome sequences. HAdV strains within the same group showed the highest nucleotide identities (99.87-100.00 %). Like HAdV-53, the hexon loop 1 and 2 regions of 870006C, 880249C and 890357C showed the highest identity with HAdV-22. However, these strains did not show a hexon-chimeric structure similar to HAdV-22 and -37, or a penton base similar to HAdV-37. The fiber genes of 870006C and 880249C were identical to that of HAdV-37, but not HAdV-8. Thus, the three intermediate HAdVs isolated in the 1980s were similar to each other but not to HAdV-53. The recombination breakpoints were inferred by the Recombination Detection Program (rdp) using whole-genome sequences of these seven HAdV and of 12 HAdV-D strains from GenBank. HAdV-53 may have evolved from intermediate HAdVs circulating in the 1980s, and from HAdV-8, -22 and -37, by recombination of sections cut at the putative breakpoints.

Complete genome analysis of a novel intertypic recombinant human adenovirus causing epidemic keratoconjunctivitis in Japan.

For 4 months from September 2008, 102 conjunctival swab specimens were collected for surveillance purposes from patients across Japan suspected of having epidemic keratoconjunctivitis (EKC). Human adenovirus (HAdV) DNA was detected in 61 samples by PCR, though the HAdV type for 6 of the PCR-positive samples could not be determined by phylogenetic analysis using a partial hexon gene sequence. Moreover, for 2 months from January 2009, HAdV strains with identical sequences were isolated from five conjunctival swab samples obtained from EKC patients in five different regions of Japan. For the analyses of the 11 samples mentioned above, we determined the nucleotide sequences of the entire penton base, hexon, and fiber genes and early 3 (E3) region, which are variable regions among HAdV types, and compared them to those of other HAdV species D strains. The nucleotide sequences of loops 1 and 2 in the hexons of all 11 samples showed high degrees of identity with those of the HAdV type 15 (HAdV-15) and HAdV-29 prototype strains. However, the fiber gene and E3 region sequences showed high degrees of identity with those of HAdV-9, and the penton base gene sequence showed a high degree of identity with the penton base gene sequences of HAdV-9 and -26. Moreover, the complete genome sequence of the 2307-S strain, which was isolated by viral culture from 1 of the 11 samples, was determined. The 2307-S strain was a recombinant HAdV between HAdV-9, -15, -26, -29, and/or another HAdV type; however, the recombination sites in the genome were not obvious. We propose that this virus is a novel intertypic recombinant, HAdV-15/29/H9, and may be an etiological agent of EKC.

Epidemiological and virological features of epidemic keratoconjunctivitis due to new human adenovirus type 54 in Japan.

BACKGROUND/AIMS: New human adenovirus (HAdV)-54 causes epidemic keratoconjunctivitis (EKC) and is virologically close to and has occasionally been detected as HAdV-8. Taking HAdV-54 into account, we re-determined HAdV type in EKC samples to determine its epidemiology in Japan, and examined the virological features of HAdV-54. METHODS: HAdV type was re-determined in 776 conjunctival swabs from Japan and 174 from six other countries, obtained between 2000 and 2009. Using 115 HAdV strains obtained before 1999, trends regarding HAdV-8 and HAdV-54 were also determined. In addition, immunochromatography (IC) kit features, DNA copy numbers and viral isolation of HAdV-54 in samples were evaluated. RESULTS: Recently, HAdV-37 and HAdV-54 have been the major causative types of EKC in Japan. HAdV-54 has been isolated each year since 1995, whereas HAdV-8 has become less common since 1997, although it remains the most common cause of EKC in the six other countries investigated where HAdV-54 is yet to be detected. HAdV-54 is comparable to other EKC-related HAdV types in terms of IC kit sensitivity and DNA copy numbers, although HAdV-54 grows more slowly on viral isolation. CONCLUSIONS: EKC due to HAdV-54 can result in epidemics; therefore, it should be accurately diagnosed and monitored as an emerging infection worldwide.

Molecular epidemiology of adenoviral keratoconjunctivitis in Saudi Arabia.

PURPOSE: Adenoviral keratoconjunctivitis is a major cause of ocular morbidity and may lead to visual loss. Adenovirus types 8, 19, and 37 may cause epidemic keratoconjunctivitis. The main objective of this study was to determine the types of adenoviruses causing keratoconjunctivitis in Saudi Arabia. METHODS: We conducted a non-interventional observational clinical study. Seventy three eyes from 65 patients who presented to The Eye Center in Riyadh, Saudi Arabia with clinical features of acute adenoviral keratoconjunctivitis were included. Each patient underwent complete clinical examination and features such as membranous reaction, conjunctival hemorrhage, subepithelial corneal infiltrates, and preauricular lymph node enlargement were recorded. Conjunctival swabs were obtained from patients with presumed acute viral conjunctivitis. Immunochromatography (IC) and restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) were performed on the conjunctival swabs obtained from each eye. Serotype identification was performed using direct sequencing technique. RESULTS: Forty-nine (67.1%) were adenovirus type 8, 8 (11.0%) were adenovirus type 3, 6 (8.2%) type 37, 5 (6.8%) were adenovirus type 4, and 2 (2.3%) type 19. The remaining 5 were types 14, 19, and 22. The prevalence of membranous conjunctivitis was highest (83%) among eyes with adenovirus type 37 while subepithelial corneal opacities were most commonly seen among eyes with adenovirus type 8 (47%). Immunochromatography tests were positive for adenovirus in 48 (65.7%) out of 73 eyes. CONCLUSIONS: This study determined the types of adenoviruses causing keratoconjunctivitis at one center in Saudi Arabia. Direct sequencing techniques is an efficient, accurate, and rapid means of diagnosing adenoviral keratoconjunctivitis. The most common causes of adenoviral keratoconjunctivitis in Saudi Arabia were adenovirus types 8, 3, and 37. Membranous conjunctivitis and subepithelial opacities had the highest frequency of adenovirus types 37 and 8, respectively. Lymph nodes enlargement was least likely in adenovirus type 4.

Emergence of clinical strains of Mycoplasma genitalium harbouring alterations in ParC associated with fluoroquinolone resistance.

Surveillance for antimicrobial resistance in Mycoplasma genitalium clinical strains is extremely limited as culturing of strains from clinical specimens is still difficult. We therefore conducted a non-cultural assessment of fluoroquinolone resistance of M. genitalium clinical strains by analysing the quinolone-resistance determining regions (QRDRs) of the gyrA and parC genes. The QRDRs amplified from M. genitalium DNA taken from urine specimens of 28 men with non-gonococcal urethritis positive for M. genitalium by polymerase chain reaction were sequenced. An amino acid change (Phe-108-->Iso) in GyrA was found in one specimen, and the same change was accompanied by an amino acid change (Lys-97-->Arg) in ParC in another specimen. A single amino acid change (Ser-83-->Asn, Asp-87-->Tyr or Asp-87-->Val) in ParC was also found in three other respective specimens without alterations in GyrA. No alterations in GyrA and ParC were found in the remaining 23 specimens. The alterations of Ser-83-->Asn, Asp-87-->Tyr and Asp-87-->Val in ParC found in 3 (10.7%) of 28 specimens were analogous to those commonly observed in fluoroquinolone-resistant mutants of other Mycoplasma and Ureaplasma spp. M. genitalium harbouring mutations associated with fluoroquinolone resistance in the parC gene may have emerged clinically and the prevalence may be ca. 10% in Japan.

A comparison of the VP1, VP2, and VP4 regions for molecular typing of human enteroviruses.

The VP4, VP2, and VP1 gene regions were evaluated for their usefulness in typing human enteroviruses. Three published RT-PCR primers sets targeting separately these three gene regions were used. Initially, from a total of 86 field isolates (36 HEV-A, 40 HEV-B, and 10 HEV-C) tested, 100% concordance in HEV-A was identified from all three gene regions (VP4, VP2, and VP1). However, for HEV-B and HEV-C viruses, only the VP2 and VP1 regions, and not VP4, showed 100% concordance in typing these viruses. To evaluate further the usefulness of VP4 in typing HEV-A enteroviruses, 55 Japanese and 203 published paired VP4 and VP1 nucleotide sequences were also examined. In each case, typing by VP4 was 100% in concordance with typing using VP1. Given these results, it is proposed that for HEV-A enteroviruses, all three gene regions (VP4, VP2, and VP1), would be useful for typing these viruses. These options would enhance the capability of laboratories in identifying these viruses and would greatly help in outbreaks of hand, foot, and mouth disease.

Molecular identification of adenoviral conjunctivitis in Turkey.

PURPOSE: The aim of the study was isolation of adenoviruses by cell culture and identification using polymerase chain reaction (PCR) and phylogenetic analyses in patients clinically diagnosed with viral conjunctivitis in Ankara, Turkey. METHODS: Conjunctival swabs from 34 patients with acute conjunctivitis were tested using cell culture isolation and PCR for adenovirus detection. PCR-positive samples were sequenced and typed. RESULTS: The positive results of adenovirus were 26.5% (9 of 34) by the PCR method and 20.6% by culture isolation. Nine samples positive at PCR were identified by phylogenetic analyses as human adenovirus 8 (HAdV-8) (4 of 9), HAdV-3 (3 of 9), HAdV-4 (1 of 9), and HAdV-B (1 of 9). CONCLUSIONS: Our study showed types of adenoviruses in patients with ocular infection that occurred in this region of Turkey for the first time. Furthermore, sequence-based typing method is an efficient, accurate, and rapid means of diagnosis and typing of the adenovirus and has significant clinical and epidemiologic implications. HAdV-8 was major type for acute conjunctivitis in Ankara, Turkey. Further studies are required to reveal the major types of HAdVs that cause ocular diseases in this region of the world.

Nucleotide sequence variation in the hexon gene of human adenovirus type 8 and 37 strains from epidemic keratoconjunctivitis patients in Japan.

Human adenovirus type 8 (HAdV-8) and 37 (HAdV-37) cause epidemic keratoconjunctivitis (EKC) associated with community-acquired and nosocomial infections. The nucleotide sequences of the entire hexon and fiber genes of eight HAdV-8 and 26 HAdV-37 strains were analysed and the transition mutations in each gene were compared among strains. Compared with prototype strains, the hexon gene of HAdV-8 and -37 strains showed between two and seven and one and twelve variations at nine and 21 different positions, respectively. All of these, except one position in HAdV-37, were located in the conserved region 4 (C4). There were only three polymorphisms in the fiber gene of both HAdV-8 and HAdV-37, fewer than those in C4. The nucleotide sequence of HAdV-8 and -37 C4 might be readily modified during EKC epidemics.

RETRACTED: Spread of epidemic keratoconjunctivitis due to a novel serotype of human adenovirus in Japan.

This article has been retracted.

Analysis of the complete genome sequence of epidemic keratoconjunctivitis-related human adenovirus type 8, 19, 37 and a novel serotype.

We determined the complete genome sequence of epidemic keratoconjunctivitis (EKC)-related human adenoviruses (HAdVs). We analysed a total of 12 HAdV strains; three prototype strains and two HAdV-8, three HAdV-19 and three HAdV-37 clinical isolates from EKC patients in Japan, and one novel serotype of HAdV. Genome organization of these serotypes was identical to those of the recently determined HAdV-19 and HAdV-37. The identities of the whole genome were over 99 % among strains from the same serotype, except for HAdV-19p, which is not associated with conjunctivitis, resulting in the formation of a distinct cluster in the phylogenetic analysis. The penton, loop 1 and loop 2 of hexon, early region 3 (E3) and fiber were hypervariable regions between serotypes. Results suggest that the HAdV-19 clinical strain is a recombinant of HAdV-19p-like and HAdV-37-like strains, and that the acquisition of the penton, E3 or fiber may be related to ocular tropism.

Epidemic keratoconjunctivitis due to the novel hexon-chimeric-intermediate 22,37/H8 human adenovirus.

In a 2-month period in 2003, we encountered an outbreak of epidemic keratoconjunctivitis (EKC) in Japan. We detected 67 human adenoviruses (HAdVs) by PCR from eye swabs of patients with EKC at five eye clinics in different parts of Japan. Forty-one of the 67 HAdV DNAs from the swabs were identified as HAdV-37 by phylogenetic analysis using a partial hexon gene sequence. When the restriction patterns of these viral genomes were compared with that of the HAdV-37 prototype strain, one isolate showed a never-before-seen restriction pattern. Within 1 year, we encountered three more EKC cases caused by a genetically identical virus: two nosocomial infections at two different university hospitals and a sporadic infection at an eye clinic. We determined the nucleotide sequences of the full-length hexon and fiber genes of these isolates and compared them to those of the 51 prototype strains. Surprisingly, the sequence of the hexon (epsilon determinant) loop-1 and -2 regions showed the highest nucleotide identity with HAdV-22, a rare EKC isolate. However, the nucleotide sequence of the fiber gene was identical to that of the HAdV-8 prototype strain. 22 We propose that this virus is a new hexon-chimeric intermediate HAdV-22,37/H8, and may be an etiological agent of EKC.

Detection of four genetic subgroup-specific antibodies to human metapneumovirus attachment (G) protein in human serum.

Human metapneumovirus (hMPV) strains are classified into two genetic groups, A and B, each of which is further divided in two genetic subgroups, A1, A2, B1 and B2. hMPV encodes two major surface glycoproteins, the fusion (F) and attachment (G) proteins, which may be immunogenic and protective antigens. Although the amino acid sequences of hMPV F protein are highly conserved, those of the G protein are highly variable with low amino acid identity between the two groups. To address the antigenic variation between the genetic subgroups, we developed an immunofluorescence assay (IFA) method using Trichoplusia ni (Tn5) insect cells infected with each recombinant baculovirus-expressed hMPV G (Bac-G) protein of the four genetic subgroups. The titre of each antibody to the four Bac-G proteins was measured by the IFA in 12 paired serum samples obtained from children infected with hMPV of each genetic subgroup. Although 11 of the 12 acute-phase serum samples in paired samples were negative for the antibody to any Bac-G proteins, all of the convalescent-phase serum samples in those paired samples were positive for the antibody to only one of the four Bac-G proteins of the infecting genotype of hMPV. Since the antibody response to hMPV G protein was transient and genetic subgroup-specific without cross-reactivity, four genetic subgroups on the basis of hMPV G protein could be identified as different serotypes. This assay may be useful for the study of immune responses of humans to different hMPV strains, especially for clarifying the risk of reinfection with hMPV.

Novel human adenovirus causing nosocomial epidemic keratoconjunctivitis.

In 2000, we encountered cases of nosocomial infections with epidemic keratoconjunctivitis (EKC) at a university hospital in Kobe, in the western part of Japan. Two human adenovirus (HAdV) strains, Kobe-H and Kobe-S, were isolated from patients with nosocomial EKC infection. They were untypeable by existing neutralizing antisera; however, the isolate was neutralized with homologous antisera. We then encountered several cases of EKC due to nosocomial infections in eye clinics in different parts of Japan. A total of 80 HAdVs were isolated from patients with EKC at eight different hospitals. The partial hexon gene sequences of the isolates were determined and compared to those of the prototype strains of 51 serotypes. All isolates had identical partial hexon nucleotide sequences. Phylogenetic analysis classified these isolates into species of HAdV-D. The isolates showed 93.9 to 96.7% nucleotide identity with HAdV-D prototype strains, while all 32 HAdV-D prototype strains ranged from 93.2 to 99.2% identity. The sequences of the loop 2 and fiber knob regions from the representative strain, Kobe-H, were dissimilar in all prototype strains of 51 serotypes. We believe that this virus is a novel serotype of HAdV that causes EKC.

Rapid detection of the mosaic structure of the Neisseria gonorrhoeae penA Gene, which is associated with decreased susceptibilities to oral cephalosporins.

In Neisseria gonorrhoeae, the mosaic structure of the penA gene (encoding penicillin-binding protein 2 [PBP 2]), which is composed of fragments of the penA genes from Neisseria cinerea and Neisseria perflava, has been significantly associated with decreased susceptibility to cephalosporins, particularly oral cephalosporins. The aim of this study was to develop a rapid assay for the detection of mosaic PBP 2 of N. gonorrhoeae by real-time PCR. This assay successfully detected the mosaic penA gene of N. gonorrhoeae, and its sensitivity was >or=10(1) copies/reaction. Six hundred twenty-one clinical strains were examined by this assay for the presence of mosaic PBP 2, which was detected in 85 (39.4%) of 216 strains from 2002, 69 (40.6%) of 170 strains from 2003, 71 (44.4%) of 160 strains from 2004, and 31 (41.3%) of 75 strains from 2005. The MICs of cephalosporins for strains with the mosaic PBP 2 detected by the assay were statistically higher than those for strains without the mosaic PBP 2. One hundred sixty-six (64.8%) of 256 strains with the mosaic PBP 2 exhibited cefixime MICs of >or=0.5 microg/ml. The emergence and spread of strains with mosaic PBP 2 could be a threat to the cefixime treatment of gonorrhea. This real-time PCR assay for the detection of mosaic PBP 2 of N. gonorrhoeae is thus useful in the prediction of decreased susceptibilities to oral cephalosporins.