Summary.A polymerase chain reaction (PCR) method was developed that was capable of detecting a wide range of medically important fungi from clinical specimens. The primer pair was designed in conserved sequences of 1 8s-ribosomal RNA genes shared by most fungi. The lower limit of detection of this PCR technique was 1 pg of Cundidu ulbicans genomic DNA by ethidium bromide staining and 100 fg after Southern analysis. A 687-bp product was amplified successfully by PCR from all 78 strains of 25 medically important fungal species studied, including Candida spp., Hansenula spp., Saccharomyces cereuisiae, Cryptococcus neoformans, Trichosporon beigelii, Malassezia furfur, Pneumocystis curinii, Aspergillus spp., and Penicillium spp., but not from any strains of Mucor spp., Escherichia coli, or methicillinresistant Staphylococcus aureus (MRSA), calf thymus or human placenta. This specificity was subsequently confirmed by Southern analysis. PCR analysis of blood specimens collected from mice systemically infected with C. albicans and clinical samples including blood, cerebrospinal fluid and sputum appeared to be a more sensitive diagnostic method for invasive fungal infections than a conventional blood culture technique.
A total of 395 Haemophilus influenzae strains from 226 Japanese institutions participating in the Nationwide Surveillance Study Group for Bacterial Meningitis were received from 1999 to 2002. All strains were analyzed by PCR to identify the resistance genes, and their susceptibilities to -lactam agents were determined. Of these strains, 29.1% were -lactamase nonproducing and ampicillin (AMP) susceptible (BLNAS) and lacked all resistance genes; 15.4% were -lactamase producing and AMP resistant and had the bla TEM-1 gene; 30.6% were -lactamase nonproducing and AMP resistant (low-BLNAR) and had a Lys-526 or His-517 amino acid substitution in ftsI encoding PBP 3; 13.9% were -lactamase nonproducing and AMP resistant (BLNAR) and had an additional substitution of Thr-385 in ftsI; 9.1% were amoxicillin-clavulanic acid resistant (BLPACR I) and had the bla TEM-1 gene and a Lys-526 or His-517 amino acid substitution in ftsI; and 1.8% showed resistance similar to that of the BLPACR I group (BLPACR II) but had bla TEM-1 gene and ftsI substitutions, as was the case for the BLNAR strains. All but three strains were serotype b. The prevalence of BLNAR strains has increased rapidly: 0% in 1999, 5.8% in 2000, 14.1% in 2001, and 21.3% in 2002. The MICs at which 90% of BLNAR isolates were inhibited were as follows: AMP, 16 g/ml; cefotaxime, 1 g/ml; ceftriaxone, 0.25 g/ml; and meropenem, 0.5 g/ml. All of these values were higher than those for the BLNAS counterpart strains. The relatively wide distributions of the -lactam MICs for BLNAR strains presumably reflect variations in ftsI gene mutations. Pulsed-field gel electrophoresis suggested the rapid spread of specific H. influenzae type b strains throughout Japan. Expedited vaccination, rapid identification, and judicious antibiotic use could slow their spread.Penicillin-intermediate Streptococcus pneumoniae and penicillin-resistant S. pneumoniae isolates from patients with respiratory tract infections (RTIs) have emerged and increased in number in Japan since 1988 (1). In contrast to the phenotypes of S. pneumoniae isolates from the United States (15), strains with an abnormal PBP 2X and strains for which penicillin G MICs at which 50% of isolates are inhibited (MIC 50 s) were 0.06 g/ml and cefotaxime (CTX) MIC 50 s were 0.125 to 0.5 g/ml accounted for 20% of all strains collected throughout Japan between 1998 and 2000 (22). The high prevalence of these resistant organisms is attributed to the frequent use of oral and intravenous cephem antibiotic agents in Japan (15,22). A similar situation is now evident among Haemophilus influenzae isolates from patients with RTIs, in which a rapid increase in the number of -lactamase-nonproducing, ampicillin (AMP)-resistant (BLNAR) H. influenzae strains has been detected (11,23). Resistance in BLNAR strains results from mutations in the ftsI gene encoding PBP 3, which mediates septal peptidoglycan synthesis (24). Amino acid substitutions identified at three positions in the ftsI gene are very important for resistance phenotypes: (i) Asn-...
BackgroundStreptococcus dysgalactiae subsp. equisimilis (SDSE) causes invasive streptococcal infections, including streptococcal toxic shock syndrome (STSS), as does Lancefield group A Streptococcus pyogenes (GAS). We sequenced the entire genome of SDSE strain GGS_124 isolated from a patient with STSS.ResultsWe found that GGS_124 consisted of a circular genome of 2,106,340 bp. Comparative analyses among bacterial genomes indicated that GGS_124 was most closely related to GAS. GGS_124 and GAS, but not other streptococci, shared a number of virulence factor genes, including genes encoding streptolysin O, NADase, and streptokinase A, distantly related to SIC (DRS), suggesting the importance of these factors in the development of invasive disease. GGS_124 contained 3 prophages, with one containing a virulence factor gene for streptodornase. All 3 prophages were significantly similar to GAS prophages that carry virulence factor genes, indicating that these prophages had transferred these genes between pathogens. SDSE was found to contain a gene encoding a superantigen, streptococcal exotoxin type G, but lacked several genes present in GAS that encode virulence factors, such as other superantigens, cysteine protease speB, and hyaluronan synthase operon hasABC. Similar to GGS_124, the SDSE strains contained larger numbers of clustered, regularly interspaced, short palindromic repeats (CRISPR) spacers than did GAS, suggesting that horizontal gene transfer via streptococcal phages between SDSE and GAS is somewhat restricted, although they share phage species.ConclusionGenome wide comparisons of SDSE with GAS indicate that SDSE is closely and quantitatively related to GAS. SDSE, however, lacks several virulence factors of GAS, including superantigens, SPE-B and the hasABC operon. CRISPR spacers may limit the horizontal transfer of phage encoded GAS virulence genes into SDSE. These findings may provide clues for dissecting the pathological roles of the virulence factors in SDSE and GAS that cause STSS.
Both Helicobacter pylori and "Candidatus Helicobacter heilmannii" infections are associated with peptic ulcers, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphomas. However, good animal models of H. pylori clinical diseases are rare. In this study, we aimed to establish an animal model of "Candidatus Helicobacter heilmannii" gastric MALT lymphoma. We used a urease-positive gastric mucosal and mucus homogenate from a cynomolgus monkey maintained in C57BL/6 mouse stomachs. The bacterium in the homogenate was identified as "Candidatus Helicobacter heilmannii" based on a DNA sequence analysis of the 16S rRNA and urease genes. Mucosal and mucus homogenates were used to inoculate C57BL/6 mice, which were then examined for 24 months. We observed a gradual increase in the surface area of protrusive lesions in almost all infected C57BL/6 mouse fundic stomachs 6 months after infection. Light microscopic observations revealed an accumulation of B lymphocytes along with destruction of glandular elements and the presence of lymphoepithelial lesions consistent with low-grade MALT lymphomas. Electron microscopic observation revealed numerous "Candidatus Helicobacter heilmannii" bacilli in the fundic glandular lumen, the intracellular canaliculi, and the cytoplasm of intact cells, as well as damaged parietal cells. In conclusion, "Candidatus Helicobacter heilmannii" induced gastric MALT lymphomas in almost 100% of infected C57BL/6 mice after a 6-month period associated with the destruction of parietal cells.
We have developed a real-time reverse transcription-PCR (RT-PCR) method to detect 13 respiratory viruses: influenza virus A and B; respiratory syncytial virus (RSV) subgroup A and B; parainfluenza virus (PIV) 1, 2, and 3; adenovirus; rhinovirus (RV); enterovirus; coronavirus (OC43); human metapneumovirus (hMPV); and human bocavirus (HBoV). The new method for detection of these viruses was applied simultaneously with real-time PCR for the detection of six bacterial pathogens in clinical samples from 1700 pediatric patients with community-acquired pneumonia (CAP). Of all the patients, 32.5% were suspected to have single bacterial infections; 1.9%, multiple bacterial infections; 15.2%, coinfections of bacteria and viruses; 25.8%, single viral infections; and 2.1%, multiple viral infections. In the remaining 22.6%, the etiology was unknown. The breakdown of suspected causative pathogens was as follows: 24.4% were Streptococcus pneumoniae, 14.8% were Mycoplasma pneumoniae, 11.3% were Haemophilus influenzae, and 1.4% were Chlamydophila pneumoniae. The breakdown of viruses was as follows: 14.5% were RV, 9.4% were RSV, 7.4% were hMPV, 7.2% were PIV, and 2.9% were HBoV. The new method will contribute to advances in the accuracy of diagnosis and should also result in the appropriate use of antimicrobials.
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