Etiology of pulmonary infections in predominantly HIV-infected adults with suspected tuberculosis, Botswana.

SETTING: In countries with high HIV rates, diagnosis of lower respiratory disease etiology is both challenging and clinically important. OBJECTIVE: To determine the etiology of lower respiratory tract disease among persons with suspected tuberculosis (TB) and abnormal chest X-rays in a setting with very high HIV seroprevalence. DESIGN: Cross-sectional prevalence data from a prospective cohort of predominantly hospitalized adults with suspected TB in Botswana, January-December 1997. RESULTS: Of 229 patients, 86% were HIV-positive and 71% had a pathogen identified. TB was confirmed in 52%, 17% had acute mycoplasma pneumonia, 3% had Pneumocystis carinii, 27% grew a bacterial pathogen from sputum and 8% from blood. Ninety-four per cent of TB diagnoses were made through expectorated sputum and only 5% of TB cases were diagnosed by sputum induction alone. Polymerase chain reaction (PCR) for Mycobacterium tuberculosis had positive and negative predictive values of 94% and 59%, respectively. Male sex, cough < 2 weeks, and tuberculin skin test > or = 5 mm were independently associated with culture-positive TB among persons with negative acid-fast bacilli smears. Co-infection with two or more pathogens occurred in 25%. CONCLUSIONS: Mycoplasma pneumoniae infection was quite common despite clinical suspicion of TB, and sputum induction and PCR did not significantly improve our ability to diagnose TB, although clinical presentation had some predictive value.

Sequence variation in the cytochrome oxidase I, internal transcribed spacer 1, and Ts14 diagnostic antigen sequences of Taenia solium isolates from South and Central America, India, and Asia.

We examined the genetic variability in the pig-human tapeworm, Taenia solium, by sequencing the genes for cytochrome oxidase I, internal transcribed spacer 1, and a diagnostic antigen, Ts14, from individual cysts isolated from Peru, Colombia, Mexico, India, China, and the Philippines. For these genes, the rate of nucleotide variation was minimal. Isolates from these countries can be distinguished based on one to eight nucleotide differences in the 396 nucleotide cytochrome oxidase I (COI) sequence. However, all of the 15 isolates from within Peru had identical COI sequences. The Ts14 sequences from India and China were identical and differed from the Peru sequence by three nucleotides in 333. These data indicate that there is minimal genetic variability within the species T. solium. Minimal variability was also seen in the ITS1 sequence, but this variation was observed within the individual. Twenty-two cloned sequences from six isolates sorted into 13 unique sequences. The variability observed within the sequences from individual cysts was as great as the variability between the isolates.

Genetic variation in Pneumocystis carinii isolates from different geographic regions: implications for transmission.

To study transmission patterns of Pneumocystis carinii pneumonia (PCP) in persons with AIDS, we evaluated P. carinii isolates from patients in five U.S. cities for variation at two independent genetic loci, the mitochondrial large subunit rRNA and dihydropteroate synthase. Fourteen unique multilocus genotypes were observed in 191 isolates that were examined at both loci. Mixed infections, accounting for 17.8% of cases, were associated with primary PCP. Genotype frequency distribution patterns varied by patients' place of diagnosis but not by place of birth. Genetic variation at the two loci suggests three probable characteristics of transmission: that most cases of PCP do not result from infections acquired early in life, that infections are actively acquired from a relatively common source (humans or the environment), and that humans, while not necessarily involved in direct infection of other humans, are nevertheless important in the transmission cycle of P. carinii f. sp. hominis.

New cryptosporidium genotypes in HIV-infected persons.

Using DNA sequencing and phylogenetic analysis, we identified four distinct Cryptosporidium genotypes in HIV-infected patients: genotype 1 (human), genotype 2 (bovine) Cryptosporidium parvum, a genotype identical to C. felis, and one identical to a Cryptosporidium sp. isolate from a dog. This is the first identification of human infection with the latter two genotypes.

Fast and reliable extraction of protozoan parasite DNA from fecal specimens.

BACKGROUND: Polymerase chain reaction (PCR) detection of intestinal protozoa in fecal specimens is hampered by poor recovery of DNA and by the presence of PCR inhibitors. In this study we describe a novel method for DNA extraction from such specimens containing spores and oocysts of Enterocytozoon bieneusi and Cryptosporidium parvum, respectively. METHODS AND RESULTS: Extraction was done using commercial kits modified to maximize the recovery and purity of extracted DNA. In comparison with a procedure we previously reported, we estimate that this method may increase the sensitivity of parasite DNA detection in fecal specimens up to tenfold. An additional advantage of this method is that up to 12 samples may be processed simultaneously within 2 hours. CONCLUSIONS: By using this method, we were able to increase reproducibility of PCR amplification on fecal specimens and significantly reduce the hands-on time required to process the samples.

Identification of Cryptosporidium felis in a cow by morphologic and molecular methods.

Apicomplexan Cryptosporidium parasites infect a wide range of vertebrate hosts. While some species are limited to a single host group, such as Cryptosporidium baileyi, which infects chickens, other species of this genus, such as C. parvum, infect a wide range of mammalian species from mice to humans. During an investigation of Cryptosporidium infection in cattle on a farm in northern Poland, we identified an infection caused by C. felis, in addition to known infections with C. muris and C. parvum. This new infection was identified based on the size of the oocysts (mean size, 4.3 +/- 0.4 micrometer; range, 3.5 to 5.0 micrometer), as well as by analysis of the molecular sequence of the variable region of the small-subunit rRNA. This finding demonstrates the complex host specificity and circulation in the environment of Cryptosporidium species.

Marcaçäo in vitro de hemácias com tecnécio-99m: aplicaçäo clínica em cintilografia esplênica seletiva; nota técnica / \"In vitro\" labeling of red blood cells with technetium-99m: clinical application for selective splenic scintigraphy - techinical note

A cintilografia esplênica seletiva pode ser o exame de eleiçäo quando há a necessidade de se estudar especificamente o baço. Para isso, descrevemos um método simplificado para marcaçäo in vitro de hemácias com tecnécio-99m com posterior desnaturaçäo térmica. Através dessa técnica é possível obter imagem cintilográfica esplênica com um número mais reduzido de manipulaçöes, quando comparada a métodos similares