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Biomedical subjects

D H Persing

Publications and source records attributed to D H Persing.

At least 127 records · Page 7Linked to original sources
PubMed1995

Two geographically distinct isolates of Borrelia burgdorferi from the United States share a common unique ancestor.

The genetic diversity of Borrelia burgdorferi isolates from several geographic regions was evaluated by nucleotide sequence analysis of the genes encoding 23S ribosomal RNA and outer surface protein A. Comparison of nucleotide sequences spanning 738 bp of the 23S ribosomal DNA from two unusual isolates, DN127 (Del Norte County, California) and 25015 (Millbrook, New York), to homologous sequences from other B. burgdorferi isolates from the United States and Russia identified several nucleotide sequence polymorphisms that are unique to these two isolates. Sequence analysis of a 615 nucleotide segment of the gene encoding outer surface protein A also revealed greater similarity of strains DN127 and 25015 (94.1%) compared to other US and Eurasian isolates. These data were further corroborated by genomic macrorestriction analysis, in which DN127 and 25015 demonstrated unique restriction digestion patterns. Our findings suggest that substantial genetic diversity of B. burgdorferi, rivaling that of European strains, exists among isolates from the United States. Strains DN127 and 25015 are unique among all B. burgdorferi isolates tested to date, and though isolated from opposite longitudinal extremes of the North American continent, are closely related.

Bacterial Outer Membrane Proteins↗
PubMed1995

Human babesiosis.

OBJECTIVE: To describe a case of human babesiosis and review the literature on the disease. MATERIAL AND METHODS: We describe a 62-year-old man with babesiosis, outline his clinical course and response to therapy, and discuss the use of the polymerase chain reaction for the diagnosis and monitoring of the infection. RESULTS: The onset of the disease was insidious, with fatigue, fever, weight loss, intermittently discolored urine, and anemia. Computed tomography of the abdomen revealed a small, shrunken spleen with an irregular border. With treatment, the symptoms gradually resolved. Although peripheral blood smears were negative soon after therapy, Babesia microti DNA was detected by polymerase chain reaction 53 days after initial examination. CONCLUSION: The development of improved methods for diagnosis, including indirect immunofluorescent antibody assays and the polymerase chain reaction, provides more sensitive detection of the parasitemia associated with babesiosis. Use of these methods may help to delineate the complete clinical spectrum of this infection and its geographic distribution in the United States.

Babesiosis↗
PubMed1995

Blood donors who are repeatedly reactive for hepatitis C virus on enzyme immunoassay and positive on recombinant immunoblot assay: evidence of failure to identify some risk factors.

BACKGROUND: Despite the introduction of surrogate testing and subsequent antibody testing of donor blood, transmission of hepatitis C virus (HCV) still occurs. The institution from which this report originates is a medical center, and many of the blood donors have also been seen as patients at the institution. This provided an opportunity for comparison of donor questionnaire responses and medical history information and for correlation of those findings with HCV test results. STUDY DESIGN AND METHODS: HCV polymerase chain reaction (PCR) testing was performed on nine stored frozen sera from donors or former donors with previous positive results on HCV enzyme immunoassay (EIA) (first- or second-generation) and recombinant immunoblot assay (RIBA) (first- or second-generation). The medical histories were also reviewed for 22 of 23 such HCV EIA-repeatedly reactive, RIBA-positive donors and 88 randomly chosen HCV-negative donors. The lifestyle information was compared with the donors' responses on the blood donation questionnaires. The data were then correlated with available clinical and laboratory evidence of HCV transmission to transfusion recipients. RESULTS: For eight donors, there were no recipients of their blood to be assessed. For 9 of the remaining 15 donors, there were recipients who were tested for HCV. Recipients of blood from 5 of these 9 donors were repeatedly reactive for HCV; while recipients of blood from 4 donors were not. Donor PCR positivity correlated with apparent transmission (p = 0.047). Twelve of 20 HCV EIA-positive donors for whom history and questionnaires were available for comparison had at least one suggestive lifestyle or established risk factor in their medical records, while none of 88 HCV-negative controls did (p < 0.0001). The data did not indicate that paid donation correlated with failure to disclose these factors. CONCLUSION: Despite more explicit and intrusive donor questioning, it is still not possible to identify all possible risk factors at donations, though many donors who do not disclose all their risk factors are eliminated from the pool by the increasingly sensitive donor tests. As long as tests are not completely foolproof, workers must be vigilant regarding the ability to elicit complete information on a donor's risk. Further study is required to determine the best way(s) to do so.

Blood↗
PubMed1995

Ixodes dammini as a potential vector of human granulocytic ehrlichiosis.

Little is known about the epidemiology and mode of transmission of the agent of human granulocytic ehrlichiosis (HGE). Analyses of an engorged female Ixodes dammini tick removed from an HGE patient and 101 field-collected I. dammini and Dermacentor variabilis from three Wisconsin counties for Borrelia burgdorferi and Ehrlichia phagocytophila/Ehrlichia equi DNA revealed that the patient tick and 7 of 68 I. dammini ticks from Washburn County collected in 1982 and 1991 were positive for ehrlichial DNA; 10 ticks from the same collections were positive for B. burgdorferi. Two specimens (2.2%) were positive for both organisms. Serologic evidence for exposure to the agent of HGE or its relatives was detected in 3 of 25 Lyme disease patients from the upper Midwest. These data argue that I. dammini is a common vector for transmission of both Lyme disease and HGE.

Animals↗
PubMed1995

Circumvention of outer surface protein A immunity by host-adapted Borrelia burgdorferi.

Outer surface protein A (OspA), which is abundantly expressed in cultured Borrelia burgdorferi, appears to be down-regulated or masked following low-dose infection, and OspA immunization did not prevent infection, dissemination, or disease development with host-adapted spirochetes. Seroconversion of mice to B. burgdorferi OspA depended on dose and viability of inoculated spirochetes. Mice inoculated with > 10(4) live spirochetes and > 10(7) heat-killed spirochetes seroconverted to OspA, but mice inoculated with fewer spirochetes did not seroconvert to OspA at 2 weeks after inoculation. Growth temperature of spirochetes was not a factor for infectious dose or seroconversion to OspA. Spirochetes grown at 30, 34, or 38 degrees C had the same median infectious dose. Growth temperature did not influence infectious dose when mice were inoculated intraperitoneally or intradermally and did not influence dose-related immunologic recognition of OspA. Mice hyperimmunized with recombinant OspA-glutathione S-transferase (GT) fusion protein or GT (controls) were challenged by syringe inoculation with 10(3) spirochetes or by transplantation of infected skin from syngenic mice infected for 2 or 8 weeks. OspA-GT-immunized mice resisted syringe challenge but developed disseminated infections following transplantation of infected skin. Identical results were obtained in mice passively immunized with hyperimmune serum to OspA-GT or GT and then challenged by syringe or infected skin transplant. The number of spirochetes in infected skin, determined by quantitative PCR directed toward both plasmid and genomic targets, was less than the syringe challenge dose.

Adaptation, Physiological↗
PubMed1995

Direct genotypic detection of Mycobacterium tuberculosis rifampin resistance in clinical specimens by using single-tube heminested PCR.

Recent analysis of the gene encoding the beta subunit of Mycobacterium tuberculosis RNA polymerase (rpoB) has demonstrated a small region that harbors the mutations most frequently associated with rifampin resistance. Earlier reports have described a high degree of sequence conservation of rpoB among mycobacteria other than M. tuberculosis and other GC-rich bacteria that can lead to false-positive amplification when applied directly to clinical specimens. We developed reagents for PCR amplification that are based on signature nucleotides discovered by comparative sequence analysis of the rpoB genes of organisms phylogenetically related to M. tuberculosis. The specificities of the reagents were challenged with 20 isolates of multiple-drug-resistant M. tuberculosis and more than 20 species of mycobacteria other than M. tuberculosis and other GC-rich organisms. A single-tube heminested PCR protocol was devised to obtain sensitivity equal to those of an IS6110-based PCR assay and culture in spiked sputum experiments. The assay correctly identified 21 of 24 (87.5%) culture-positive specimens, 13 of which were acid-fast smear-negative, in a panel of 51 clinical specimens. Three specimens that were false-positive initially were negative upon repeat testing when the assay was modified to eliminate the potential for aerosol carryover of the first-round amplification product during the open-tube addition of the second set of reaction reagents. This assay is the most sensitive and specific test to date for the direct detection of M. tuberculosis rpoB in clinical specimens. This rapid PCR-based assay can be used for the simultaneous identification of M. tuberculosis and its rifampin susceptibility genotype.

Amino Acid Sequence↗
PubMed1995

Genotypic detection of Mycobacterium tuberculosis rifampin resistance: comparison of single-strand conformation polymorphism and dideoxy fingerprinting.

Detection of mutations in the rpoB gene of Mycobacterium tuberculosis can be used as an accurate predictor of rifampin resistance in the majority of strains tested. Simple but highly accurate screening methods must be developed for the detection of these mutations. Either DNA sequence analysis or single-strand conformation polymorphism (SSCP) screening can be used to detect rpoB mutations, but these techniques either are expensive or yield results that may prove difficult to interpret when used in a clinical setting. This report describes the use of dideoxy fingerprinting (ddF) as a postamplification screening method to identify rifampin-resistant genotypes. The ddF protocol was performed on the amplified rpoB fragment with no preparatory steps, thus making ddF practical for laboratories equipped for polyacrylamide gel electrophoresis. When compared with the results of SSCP analysis, ddF results were more easily interpreted and contained more sequence-dependent information that facilitated differentiation of functionally significant and silent mutations. The ddF method was used for genotypic determination of rifampin susceptibility of 20 multidrug-resistant strains of M. tuberculosis. The results of this analysis were concordant with DNA sequence analysis and conventional clinical laboratory methods.

DNA Fingerprinting↗
PubMed1995

Detection of the Staphylococcal mecA gene by chemiluminescent DNA hybridization.

A new solution-phase DNA hybridization capture assay for the rapid detection of the mecA gene in clinical isolates of Staphylococcus was compared with multiplex PCR and disk diffusion methods. The assay uses a DNA capture probe immobilized on paramagnetic particles and a second DNA probe labeled with an acridinium ester. Bacteria from 24-h cultures are lysed, and the lysates are hybridized with the DNA probes. After magnetic separation to remove unhybridized labeled probe, the mecA gene is detected by the chemiluminescence of the hybridized probe. Four hundred consecutive staphylococcal isolates were assayed, including 147 S. aureus and 253 coagulase-negative Staphylococcus isolates. Among the S. aureus isolates, 14 of 147 were MecA+ by both the hybridization capture assay and PCR; 133 of 147 were MecA negative by both assays (positive and negative predictive values, 100%). Comparison of disk diffusion results with those obtained by genotypic methods indicated that 14 of 147 S. aureus isolates judged to be resistant were positive by both methods; 119 of 147 were Oxs and negative by both genotypic methods (positive and negative predictive values, 50 and 100%, respectively). The remaining 14 S. aureus isolates were MecA- Oxr; among these, 13 were beta-lactamase hyperproducers. For coagulase-negative staphylococci, 130 of 253 were MecA+ by the hybridization capture assay; 129 of 130 of these isolates were positive by PCR (positive and negative predictive values, 99.2 and 100%, respectively). Comparison with the disk diffusion assay showed that 128 of the coagulase-negative MecA+ isolates were Oxr; 111 of 253 were MecA- and Oxs (positive and negative predictive values, 90.8 and 99.1%, respectively). Thirteen coagulase-negative isolates were MecA-Oxr; among these, three were beta-lactamase hyperproducers. Comparison of the hybridization capture assay results with PCR indicates that the DNA hybridization assay is a sensitive and specific test for the detection of the mecA gene in clinical isolates of Staphylococcus.

Bacteriological Techniques↗
PubMed1995

Genotype-dependent serologic reactivities in patients infected with hepatitis C virus in the United States.

OBJECTIVE: To evaluate the serologic reactivities in patients infected with different hepatitis C virus (HCV) genotypes to four HCV proteins that are components of the second-generation recombinant immunoblot assay. MATERIAL AND METHODS: Serum samples from 36 patients with chronic HCV infection were obtained. RNA was extracted by using chaotropic lysis and isopropanol precipitation. Reverse-transcriptase polymerase chain reaction of the NS-5 region was performed, followed by automated single-pass dideoxy sequencing of desalted amplification products. Classification of isolated HCV subtypes was based on Simmonds' system. All samples were tested for antibodies to proteins 5-1-1, C100-3, C33c, and C22-3 with the second-generation recombinant immunoblot assay. RESULTS: Reactivity to protein 5-1-1 was significantly lower for patients with genotypes 2b and 3a than for those infected with HCV types 1a or 1b (P < 0.05). Antibody reactivity to the C100-3 protein was also reduced in patients infected with HCV types 2b and 3a. CONCLUSION: These data indicate that the genotype-dependent differences in serologic reactivities are substantial among patients with chronic HCV infection.

Base Sequence↗
PubMed1995

Babesiosis in Wisconsin: a potentially fatal disease.

Babesiosis is emerging as an important tick-borne zoonosis in the United States. Most reported cases of this parasitic disease have been acquired in the Northeast. To date, only two clinical cases of Babesia microti infection acquired in the upper Midwest have been described. We report eight more cases. Most if not all of the 10 total cases probably were acquired in northwestern Wisconsin. Three cases (30% of 10) we now report were fatal and occurred in elderly patients (65-75 years old) who died after complicated hospital courses. One patient probably had had a latent Babesia infection that activated because of immunosuppression attributable to high-dose corticosteroid therapy and to splenic infarctions caused by cholesterol emboli. All three fatal cases were diagnosed incidentally and highlight the importance of considering the diagnosis of babesiosis in febrile patients who have been in babesiosis-endemic areas; examining their blood smears carefully; and treating promptly with clindamycin and quinine, and, if indicated, exchange transfusion. Medical personnel should be knowledgeable about this zoonosis, which is not limited to the northeastern United States, and is potentially serious, sometimes fatal.

Aged↗
PubMed1995

Epidemiology and natural history of hepatitis C infections in liver transplant recipients.

Hepatitis C infection is common in patients undergoing liver transplantation. Few studies have focused on the prevalence and epidemiology of hepatitis C infection among liver transplant recipients since the implementation of donor screening for antibodies against the hepatitis C virus (anti-HCV). Using reverse transcription-polymerase chain reaction (RT-PCR) and genomic sequencing methods, we sought to determine the prevalence, epidemiology, and natural history of hepatitis C infections among 44 consecutive liver transplant patients between January and December 1991. All patients and donors were screened for antibodies against HCV with a first-generation test. Laboratory tests and liver biopsies were routinely done 12 months after transplantation. Serum samples from all organ donors and transplant recipients were analyzed for the presence of HCV-RNA. From four of the six HCV-RNA-positive patients, pre- and post-transplant serum samples were available for sequence analysis. No donor had detectable HCV-RNA. Six of 44 (13.6%) patients had detectable HCV-RNA before and after liver transplantation. Recurrent infection was documented in all who were infected before transplantation and was confirmed by genotype analysis in the four patients who were analyzed. No acquired infections were identified. After transplantation, the HCV-RNA-positive recipients had higher mean alanine aminotransferase (207 +/- 85 U/l vs 37 +/- 7 U/l; p < 0.0001) and were more likely to have chronic hepatitis (50% vs 6%; p < 0.03) than the HCV-RNA-negative recipients.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1995

Babesiosis: new insights from phylogenetic analysis.

Piroplasms of the genus Babesia, along with their relatives to the Theileridae, comprise a genetically and antigenically diverse group of tick-transmitted intraerythrocytic pathogens that together have considerable veterinary, medical, and economic importance. Since the first description of a human case of babesiosis in 1957, this zoonotic infection has now attained a worldwide distribution. In the northeastern and upper midwestern United States, the transmission cycle of Babesia microti overlaps that of another well-known zoonotic agent, Borrelia burgdorferi, the causative agent of Lyme disease. Phylogenetic analysis of Babesia and Babesia-like piroplasms from human and animal sources has shown that many of the small Babesia spp., including B. microti, B. equi, B. gibsoni, and a recently described piroplasm infectious for humans known as WA1, may be phylogenetically related to Theileria. Implications of this observation may include the possible existence of an exoerythrocytic stage of parasite development and attendant features of chronicity, immune suppression, and perhaps lymphoproliferation. In this review, we provide a brief summary of recent developments in the study of Babesia and related piroplasms and speculate on the ramifications of chronic babesial infection in humans.

Adolescent↗
PubMed1994

The stem-loop structure of the cis-encapsidation signal is highly conserved in naturally occurring hepatitis B virus variants.

The region encoding the stem-loop structure of the HBV cis-encapsidation signal was sequenced in 87 patients with various forms of hepatitis. Altogether, 20 nucleotide substitutions were found; 15/20 were predicted to increase the stability of the stem-loop structure. Substitutions likely to decrease the stability of the cis-encapsidation signal were not observed.

Base Sequence↗
PubMed1994

Detection of Borrelia burgdorferi DNA by polymerase chain reaction in synovial fluid from patients with Lyme arthritis.

BACKGROUND: Borrelia burgdorferi is difficult to detect in synovial fluid, which limits our understanding of the pathogenesis of Lyme arthritis, particularly when arthritis persists despite antibiotic therapy. METHODS: Using the polymerase chain reaction (PCR), we attempted to detect B. burgdorferi DNA in joint-fluid samples obtained over a 17-year period. The samples were tested in two separate laboratories with four sets of primers and probes, three of which target plasmid DNA that encodes outer-surface protein A (OspA). RESULTS: B. burgdorferi DNA was detected in 75 of 88 patients with Lyme arthritis (85 percent) and in none of 64 control patients. Each of the three OspA primer-probe sets was sensitive, and the results were moderately concordant in the two laboratories (kappa = 0.54 to 0.73). Of 73 patients with Lyme arthritis that was untreated or treated with only short courses of oral antibiotics, 70 (96 percent) had positive PCR results. In contrast, of 19 patients who received either parenteral antibiotics or long courses of oral antibiotics (> or = 1 month), only 7 (37 percent) had positive tests (P < 0.001). None of these seven patients had received more than two months of oral antibiotic treatment or more than three weeks of intravenous antibiotic treatment. Of 10 patients with chronic arthritis (continuous joint inflammation for one year or more) despite multiple courses of antibiotics, 7 had consistently negative tests in samples obtained three months to two years after treatment. CONCLUSIONS: PCR testing can detect B. burgdorferi DNA in synovial fluid. This test may be able to show whether Lyme arthritis that persists after antibiotic treatment is due to persistence of the spirochete.

Adolescent↗
PubMed1994

Lack of evidence for hepatitis B virus (HBV) infection in fulminant non-A, non-B hepatitis.

We studied eight patients who had orthotopic liver transplantation for fulminant hepatic failure in the course of acute non-A, non-B hepatitis. HBV DNA was searched for extensively in the liver tissue by PCR using several sets of primers in conventional and heminested reactions. All patients were negative for HBV DNA in liver tissue by all assays employed; furthermore, they were negative for HEV RNA, HCV RNA, and HBV DNA in serum. Although the causative role of HEV and HCV in fulminant non-A, non-B hepatitis cannot be excluded, our data do not support a causative association between this syndrome and HBV infection.

Base Sequence↗
PubMed1994

Nucleotide sequence analysis of the precore region in patients with spontaneous reactivation of chronic hepatitis B.

The role of HBV precore mutations in the spontaneous reactivation of chronic hepatitis B (CHB) is currently unknown. We studied 10 patients with CHB; five were HBeAg+ (group I) and five were anti-HBe+ (group II). All 10 had spontaneous reactivation of CHB as defined by the appearance of clinical symptoms along with an increase of serum ALT activity at least 5X above baseline values, in the absence of any other known causes of liver disease or CHB reactivation. The precore (87 nt) and proximal core (81 nt) regions were sequenced after PCR amplification. From each patient three serum samples studied: one 3-12 months before, one during, and one six months after reactivation. Prior to reactivation, none of the group I patients harbored an HBV strain having a mutation that prevented HBeAg synthesis; however, 2/5 developed such a mutation during reactivation (G to A transition at nt 1896). Among the group II patients, three harbored an HBeAg defective mutant both before and during reactivation; after six months, two of these three patients were HBV DNA negative in serum by PCR. Several other sequence polymorphisms, some of which changed the predicted amino acid sequence, were either present initially or developed during reactivation. In conclusion, in this small group of CHB patients who were HBeAg+ spontaneous reactivation was accompanied in some cases by a shift to an HBeAg defective mutant, while in patients who were anti-HBe+, such mutations were frequently present prior to reactivation. In patients already harboring precore defective mutants, spontaneous reactivation may precede an attenuation of viral replication.

Adult↗