Experimental dermatophytosis in hamsters inoculated with Trichophyton mentagrophytes in the cheek pouch

This study presents the results of T. mentagrophytes inoculation in the cheek pouch of the hamster, an immunologically privileged site. Forty two animals were used: 21 inoculated with 10(6) fungi in the cheek pouch (group 1) and 21 inoculated initially with 10(6) fungi in the foot pad and 15 days later in the cheek pouch, with the same amount of fungi (group 2). Animals were sacrificed at 20 hours, 3, 7, 14, 30, 60, and 120 days; samples from inoculated cheek pouch, and foot pads submitted to the foot pad test (FPT), were collected. Independent of group and time of evolution of infection, animals did not develop delayed hypersensitivity evaluated through the FPT. The pre-inoculation of fungi in the foot pad did not change the morphology of lesions induced in the cheek pouch. Therefore, in animals of group 1 and 2, the introduction of the fungus in the cheek pouch resulted in focal lesion composed of a sterile acute inflammatory infiltrate, with abscess formation that evolved to a macrophagic reaction, and later to resolution even in the absence of immune response detectable by FPT. Our results indicate that in spite of the important role of the immune response in the spontaneous regression of dermatophytosis, other factors are also an integral part in the defense against this fungal infection.

Polymerase chain reaction (PCR) for the detection of Salmonella in artificially inoculated chicken meat

The aim of this study was to develop a polymerase chain reaction (PCR) protocol for the detection of Salmonella in artificially contaminated chicken meat. Tests were performed with different dilutions of Salmonella Typhimurium or Salmonella Enteritidis cells (10-7, 10-8 or 10-9 CFU/mL) inoculated in chicken meat samples, in order to establish the limits of detection, incubation times (0, 6, 8 and 24 hours of pre-enrichment in PBW 1%) and three DNA extraction protocols (phenol-chloroform, thermal treatment and thermal treatment and Sephaglass). The assay was able to detect until 10-9 CFU/mL of initial dilution of Salmonella cells inoculated in chicken meat, which allows detection of Salmonella within 48 hours, including 24 hours of pre-enrichment and using the phenol-chloroform DNA extraction protocol. As the results are obtained in a shorter time period than that of microbiological culture, this procedure will be useful in the methodology for detection of Salmonella in chicken.

Single step polymerase chain reaction (PCR) for the diagnosis of the Leishmania (Viannia) subgenus

In Brazil, the main etiologic agent of Leishmaniasis that frequently presents with mucosal involvement belongs to the Viannia subgenus. The therapeutic conduct in this disease depends on the parasitological diagnosis, and classical methods are restricted in identifying the agent. In this paper we describe a polymerase chain reaction (PCR), which uses primers designed from mini-exons repetitive sequences. The PCR amplifies a 177bp fragment that can distinguish (Viannia) from (Leishmania) subgenus. This test could be a useful diagnostic tool.

Effect of Cysticercus cellulosae fractions on the respiratory burst of pig neutrophils

Neutrophils, eosinophils and macrophages are cells that interact with invading parasites and naive hosts have been shown to have anti-parasitic activity. The initial reaction of these leukocytes is the generation of reactive oxygen species (ROS) to play in parasite expulsion. The present work was carried out to study the effect of total extract, scolex and membrane fractions from Cysticercus cellulosae on respiratory burst by pig neutrophils. Hydrogen peroxide (H2O2) production by neutrophils incubated with metacestode fractions from C. cellulosae showed an increase of: 190% (total extract), 120% (scolex) and 44% (membrane). High antioxidant catalatic activity (33%, 28%, 28% by total extract, scolex and membrane, respectively) was observed in neutrophils incubated with metacestode fractions, which could be an attempt at self-protection. Scolex and membrane fractions increased the phagocytic capacity of neutrophils (44% and 28%, respectively). On the other hand, total cysticerci did not alter the phagocytosis, possibly due to modifications in membrane function, caused by high ROS production from neutrophils in the presence of total cysticerci. Total fraction from C. cellulosae is toxic for neutrophils as shown by the decrease in phagocytic capacity, probably caused by high levels of ROS formation. The difference in toxicity of total extract, scolex and membrane fractions on neutrophils can be explained by the presence of an antigenic effect of the vesicular fluid in the total extract of C. cellulosae.

Clinical characteristics and evolution of syphilis in 24 HIV+ individuals in Rio de Janeiro, Brazil

A total of 24 patients with syphilis and HIV infection were treated from January 1997 to March 2003 at the Infectious Dermatology Outpatient Clinic of the Evandro Chagas Clinical Research Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil. The caseload consisted of 20 males (83.3%) and four females (16.7%), with a mean age of 38.04 years and mean T CD4+ count of 389.5 cells/mL. Syphilis was diagnosed as secondary in 16 (62.5%) patients, late latent in eight (33.3%), and tertiary in one (4.2%). Manifestations of secondary syphilis were palmar and plantar erythematopapulous cutaneous lesions in nine (37.5%), papulous exanthema in four (16.7%), patchy alopecia in 3 (12.5%) and osteochondritis in one patient (4.2%). Tertiary syphilis was characterized by verrucous lesions. Neurosyphilis was diagnosed in four patients (16.7%), with headache as the only manifestation in two patients. Drugs used in treatment included benzathine penicillin, ceftriaxone, erythromycin, and crystalline penicillin. Cure was achieved in 18 patients (75%). Five patients (20.8%) were retreated, three of whom presented a history of re-exposure. This study confirms the importance of establishing the diagnosis of neurosyphilis in patients with HIV infection, in addition to performing follow-up on treatment for syphilis.

Abdominal angiostrongyliasis: a case with severe evolution

A case of acute abdomen disease caused by abdominal angiostrongyliasis is reported. A 42-year-old otherwise healthy patient presented with a complaint of nine days of abdominal pain, constipation, disury, fever and right iliac fossa palpable mass. Exploratory laparotomy was performed. After surgical treatment the patient presented serious complications.

Comparison of serology, antigenemia assay and the polymerase chain reaction for monitoring active cytomegalovirus infections in hematopoietic stem cell transplantation patients

Forty-six allogeneic hematopoietic stem cell transplantation (HSCT) patients were monitored for the presence of CMV antibodies, CMV-DNA and CMV antigens after transplantation. Immunoenzymatic serological tests were used to detect IgM and the increase in CMV IgG antibodies (increase IgG), a nested polymerase chain reaction (N-PCR) was used to detect CMV-DNA, and an antigenemia assay (AGM) was used to detect CMV antigens. The presence of CMV-IgM and/or CMV-increase IgG antibodies was detected in 12/46 (26.1%) patients, with a median time between HSCT and the detection of positive serology of 81.5 days. A positive AGM was detected in 24/46 (52.2%) patients, with a median time between HSCT and antigen detection of 62 days. Two or more consecutive positive N-PCR results were detected in 32/46 (69.5%) patients, with a median time between HSCT and the first positive PCR of 50.5 days. These results confirmed that AGM and mainly PCR are superior to serology for the early diagnosis of CMV infection. Six patients had CMV-IgM and/or CMV-increase IgG with a negative AGM (five cases) or N-PCR assay (one case). In five of these cases the serological markers were detected during the first 100 days after HSCT, the period of highest risk. These findings support the idea that serology may be useful for monitoring CMV infections in HSCT patients, especially when PCR is unavailable.

Comparison of direct immunofluorescence, conventional cell culture and polymerase chain reaction techniques for detecting respiratory syncytial virus in nasopharyngeal aspirates from infants

A total of 316 samples of nasopharyngeal aspirate from infants up to two years of age with acute respiratory-tract illnesses were processed for detection of respiratory syncytial virus (RSV) using three different techniques: viral isolation, direct immunofluorescence, and PCR. Of the samples, 36 (11.4%) were positive for RSV, considering the three techniques. PCR was the most sensitive technique, providing positive findings in 35/316 (11.1%) of the samples, followed by direct immunofluorescence (25/316, 7.9%) and viral isolation (20/315, 6.3%) (p < 0.001). A sample was positive by immunofluorescence and negative by PCR, and 11 (31.4%) were positive only by RT-PCR. We conclude that RT-PCR is more sensitive than IF and viral isolation to detect RSV in nasopharyngeal aspirate specimens in newborn and infants.

Indications of carbapenem resistance evolution through heteroresistance as an intermediate stage in Acinetobacter baumannii after carbapenem administration

We describe an in vivo evolution of an antimicrobial profile from susceptibility to full-resistance to carbapenems, with heteroresistance as an intermediate stage, in an Acinetobacter baumannii strain. Heteroresistance was characterized by the growth of sub-populations within the susceptibility halo in both disk-diffusion and Etest. PCRs for the main A. baumannii carbapenemases were negative. The exact resistance mechanism, diagnostic methods and clinical relevance of heteroresistance in A. baumannii warrant further investigations. This is the first description of such phenomenon in vivo and the second report of heteroresistance to carbapenems in A. baumannii.

Accidental infection by Trypanosoma cruzi follow-up by the polymerase chain reaction: case report

We report a case of accidental infection by Trypanosoma cruzi in a 42-year-old female patient who presented an inoculation chagoma. Laboratory confirmation was based on examination of fresh blood, Giemsa-stained blood smear, immunoenzyme test (EIA-IgG), indirect immunofluorescence (IIF-IgM, IgG) and polymerase chain reaction (PCR). Only the PCR gave a positive result, and the EIA test was inconclusive. Two treatments with benznidazole were necessary. PCR was the only technique that continued to give positive results for approximately two months (65 days, or 2.2 months) following the second treatment and negative results from 96 days (3.2 months) to 850 days (28.3 months). We concluded that the presence of an inoculation chagoma and use of PCR were important and decisive for diagnosis and follow-up of the case.

Effects of vitamin C supplementation on acute phase Chagas disease in experimentally infected mice with Trypanosoma cruzi QM1 strain

The tissue changes that occur in Chagas disease are related to the degree of oxidative stress and antioxidant capacity of affected tissue. Studies with vitamin C supplementation did not develop oxidative damage caused by Chagas disease in the host, but other studies cite the use of peroxiredoxins ascorbate - dependent on T. cruzi to offer protection against immune reaction. Based on these propositions, thirty "Swiss" mice were infected with T. cruzi QM1 strain and treated with two different vitamin C doses in order to study the parasitemia evolution, histopathological changes and lipid peroxidation biomarkers during the acute phase of Chagas disease. The results showed that the parasite clearance was greater in animals fed with vitamin C overdose. There were no significant differences regarding the biomarkers of lipid peroxidation and inflammatory process or the increase of myocardium in animals treated with the recommended dosage. The largest amount of parasite growth towards the end of the acute phase suggests the benefit of high doses of vitamin C for trypomastigotes. The supplementation doesn't influence the production of free radicals or the number of amastigote nests in the acute phase of Chagas disease.