All Posts Tagged With: "PCR"

Excerpt:

Dilated cardiomyopathy (DCM) represents the third most common cause of heart
failure and the most frequent cause of heart transplantation. Infectious, mostly
viral, and autoimmune mechanisms, together with genetic abnormalities, have been
reported as three major causes of DCM. We hypothesized that Lyme disease (LD),
caused by spirochete Borrelia burgdorferi (Bb), might be an important cause of
new-onset unexplained DCM in patients living in a highly endemic area for LD
such as the Czech Republic.

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Red Baby Syndrome is a new disease seen in infants and young children. Dramatic onset of clinical symptoms with high intensity, short duration and lack of similarity with other cutaneous lesions makes it distinct. Of 50 such patients studied over a period of 5 years, half were below one year of age. Abrupt onset of high fever and generalized erythema involving the entire skin, which is swollen and tender is characteristic. These children were highly irritable and had paradoxical cry when cuddled. Rapid resolution of symptoms occurred in 7-10 days with extensive desquamation. Routine investigations were normal, C-reactive protein was raised only in 10 patients. Human Parvo virus B-19 IgM antibodies were positive in 15 out of 24 patients. Real time polymerase chain reaction was positive for human parvovirus B 19 DNA in one. Histopathological changes in the skin biopsy showed post infectious vascular injury pattern.

 Borrelia burgdorferi sensu lato, carried by Ixodes ticks, is one of the
most significant human pathogens responsible for Lyme disease. As there
is no standardized method of polymerase chain reaction (PCR) for
detection and identification of spirochetes’ DNA, we carried out a
comparative analysis using a set of complementary primers for three
regions in the genomic DNA of these bacteria (genes fla, rrs and
non-coding rrs-rrlA region). DNA extracted from 579 Ixodes ricinus ticks
was subjected to nested PCR. DNA of the examined spirochetes was
detected in 43 (7.4 %) lysates when we used fla gene as molecular
marker, in 7 (1.2 %), using primers complementary to the rrs gene, and
in 12 (2.1 %) lysates complementary to the non-coding rrs-rrlA sequence.
Restriction fragment length polymorphism (RFLP) analysis, based on fla
gene, helped identify species from the B. burgdorferi sensu lato (B.
burgdorferi sensu stricto, B. afzelii, B. garinii, B. valaisiana),
detect co-infections, and also identify B. miyamotoi. Therefore the fla
gene is the most sensitive and specific molecular marker for the
detection and identification of Borrelia spirochetes in I. ricinus.

 The Lyme borreliosis agent Borrelia burgdorferi and the relapsing fever group
species Borrelia miyamotoi co-occur in the United States. We used
species-specific, quantitative polymerase chain reaction to study both species
in the blood and skin of Peromyscus leucopus mice and host-seeking Ixodes
scapularis nymphs at a Connecticut site. Bacteremias with B. burgdorferi or B.
miyamotoi were most prevalent during periods of greatest activity for nymphs or
larvae, respectively. Continued

Background: Morphea, granuloma annulare (GA) and lichen sclerosus et atrophicans (LSA) have also been suggested to be linked to Borrelia infection. Previous studies based on serologic data or detection of Borrelia by immunohistochemistry and polymerase chain reaction (PCR) reported contradictory results. Thus, we examined skin biopsies of morphea, GA and LSA by PCR to assess the prevalence of Borrelia DNA in an endemic area and to compare our results with data in the literature.

Methods: Amplification of DNA sequences of Borrelia burgdorferi sensu lato by nested PCR from formalin-fixed and paraffin-embedded skin biopsies of morphea, GA and LSA, followed by automated sequencing of amplification products. PCR-based studies on Borrelia species in these disorders published until July 2009 were retrieved by a literature search. Continued

Rates of infection of Amblyomma americanum (L.) by Ehrlichia chaffeensis were
compared in 100 ticks collected from sites in each of four states: Indiana,
North Carolina, Kentucky, and Mississippi. The overall infection rates were
similar among sites, ranging from 1 to 4%. Because pathogenic differences may
exist between E. chaffeensis strains, nested polymerase chain reaction (PCR)
amplification of the variable-length PCR target (VLPT), and sequencing of the
amplicons were performed to differentiate between strains. The most common
infecting strains at all sites exhibited a repeat profile of 1,2,3,4
(corresponding to the Arkansas/Jax/Osceola and Liberty strains). To determine
whether the minimum infection rates (MIRs) or the most common infecting strain
were changing over time in southern Indiana sites, 2765 ticks from six counties
in 2000 and 837 ticks from seven counties in 2004 also were examined in pools of
five ticks per pool. The MIRs for 2000 and 2004 were 3.5 and 4.2% respectively,
suggesting that the overall MIRs remained low. At two sites, in Pike and
Harrison counties, however, infection rates more than doubled from 2000 to 2004
(7 to 16% and 0.3 to 2.7% respectively). Across all sites, the most common
infecting strains (Arkansas/Jax/Osceola and Liberty) did not significantly
change (68% in 2000; 79% in 2004). Continued

Among the various species of hard ticks, Ixodes ricinus is the most frequently
found tick throughout Europe. As with other ixodid ticks, the developmental
cycle runs through three stages. In each stage a blood meal is required in order
to develop to the next stage. Ixodes ricinus has been found to feed on more than
300 different vertebrate species. Usually, larval ticks feed on small mammals
such as mice and become infected with various microorganisms and viruses, of
which some are substantial pathogens to humans. The pathogens remain in the tick
during molting and are thus transstadially transmitted to the next developmental
stage. Pathogens transmitted to humans are the agents of Lyme borreliosis, the
tick-borne encephalitis virus, Rickettsia species, Anaplasma phagocytophilum,
occasionally Francisella tularensis, and protozoal Babesia species. Within the
scope of an EU project Ixodes ricinus ticks from all federal states of Austria
were searched by means of PCR methods for bacterial pathogens such as Anaplasma
phagocytophilum, Borrelia burgdorferi sensu lato, Coxiella burnetii, Ehrlichia
spp., Francisella tularensis, Rickettsia spp., and protozoal Babesia.
Additionally, the prevalence of Bartonella spp. in this tick species was also
determined. Besides the singular detection of Coxiella burnetii and Francisella
tularensis in one tick collection site the overall prevalence of Anaplasma
phagocytophilum, borreliae, rickettsae and babesiae in Ixodes ricinus amounted
to 15%, 14%, 6% and surprising 36% and 51%, respectively. Bartonellae were
detected in about 7%.

A total of 559 fleas representing four species (Pulex irritans, Ctenocephalides felis, Ctenocephalides canis and Spilopsyllus cuniculi) collected on carnivores (five Iberian lynx Lynx pardinus, six European wildcat Felis silvestris, 10 common genet Genetta genetta, three Eurasian badger Meles meles, 22 red fox Vulpes vulpes, 87 dogs and 23 cats) in Andalusia, southern Spain, were distributed in 156 pools of monospecific flea from each carnivore, and tested for Bartonella infection in an assay based on polymerase chain reaction (PCR) amplification of the 16 S-23 S rRNA intergenic spacer region.

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HLA-DR alleles determine responsiveness to Borrelia burgdorferi antigens in a
mouse model of self-perpetuating arthritis.

Iliopoulou BP, Guerau-De-Arellano M, Huber BT.

Tufts University, Boston, Massachusetts.

OBJECTIVE: Arthritis is a prominent manifestation of Lyme disease, which is
caused by infection with Borrelia burgdorferi (Bb). Chronic Lyme arthritis
persisting even after antibiotic treatment is linked to HLA-DRB1*0401 (DR4) and
related alleles. In contrast, patients whose Lyme arthritis resolves within 3
months postinfection show an increased frequency of HLA-DRB1*1101 (DR11). The
aim of this study was to analyze the underlying mechanism by which HLA-DR
alleles confer genetic susceptibility or resistance to antibiotic-refractory
Lyme arthritis. Continued

Clinical practice guidelines are increasing in number. Unfortunately,
when scientific evidence is uncertain, limited, or evolving, as is often
the case, conflict often arises between guideline committees and
practicing physicians, who bear the direct responsibility for the care of
individual patients. The 2006 Infectious Diseases Society of America
guidelines for Lyme disease, which have limited scientific support,
could, if implemented, limit the clinical discretion of treating physicians
and the treatment options available to patients

Introduction

Clinical practice guidelines are now ubiquitous throughout the
United States. The National Guidelines Clearing House, under the
category “diseases,” currently lists 2,126 separate guidelines on its
web site. Clinical guidelines are intended to assist physicians in
patient care by clearly communicating the results of the guideline
committees’ evaluation of available therapeutic options. However,
the processes by which individual guidelines are constructed may be
less clear, leading to disagreements between the issuing committee
and the physicians who treat patients-physicians who may well be
as experienced and knowledgeable as the guideline committee.

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