Fatal outcomes in family transmission of Mycoplasma pneumoniae.

BACKGROUND: Mycoplasma pneumoniae continues to be a significant cause of community-acquired pneumonia and, on rare occasions, manifests as fulminant disease that leads to mortality, even in healthy individuals. METHODS: We conducted a retrospective study on members of a family who were quarantined by the Centers for Disease Control and Prevention in 2002 for respiratory failure and death of a 15-year-old brother (sibling 1) and a 13-year-old sister (sibling 2). Collected airway, cerebrospinal fluid (CSF), and serum samples from both deceased siblings and serum samples from both parents and the remaining 3 ill siblings (sibling 3-5) were tested using a range of diagnostic assays. Autopsy lung tissue samples from sibling 2 were also assessed using immunohistochemical and immunoelectron microscopic methods. RESULTS: Autopsy evaluation of sibling 1 revealed cerebral edema consistent with hypoxic ischemic encepatholopathy and pulmonary findings of bronchiolitis obliterans with organizing pneumonia (BOOP). Postmortem lung examination of sibling 2 revealed lymphoplasmacytic bronchiolitis with intraluminal purulent exudate, BOOP, and pulmonary edema. Results of diagnostic assays implicated the household transmission of M. pneumoniae among all 5 siblings and both parents. Further analysis of lung tissue from sibling 2 demonstrated the presence of M. pneumoniae organisms and community-acquired respiratory distress syndrome toxin. M. pneumoniae was cultured directly from sibling 2 autopsy lung tissue. CONCLUSION: Evidence is provided that M. pneumoniae was readily transmitted to all members of the household and that the resulting infections led to a spectrum of individual responses with variation in disease progression, including lymphoplasmacytic bronchiolitis, BOOP, and death.

Mycoplasma genitalium symptoms, concordance and treatment in high-risk sexual dyads.

The objective of this study was to determine the prevalence and concordance of Mycoplasma genitalium (MG) among Mexican American and African American women and their male sexual partners. Secondary objectives were to determine symptoms of MG infection and persistence of MG after antibiotic therapy. Heterosexual couples were tested for MG and interviewed separately regarding symptoms and behavioural/epidemiologic variables at baseline, six and 12 months. The overall prevalence of MG among women and men was 9.5% and 10.6%, respectively. Subjects were five times more likely to be infected with MG if their sexual partner was MG positive. Among men and women, MG prevalence and mean bacterial loads were similar after receiving single-dose azithromycin, doxycycline or no antibiotics. MG was associated with current urethral discharge in men. No clinical symptoms were specifically diagnostic of MG infection in women.

Characterization of cDNAs encoding adhesin proteins involved in trichomonas vaginalis cytoadherence.

Trichomonas vaginalis cytoadherence is mediated by four adhesins (AP65, AP51, AP33 and AP23). Adhesin gene expression was previously shown to be up-regulated by iron. Therefore, a cDNA library was constructed from mRNA of T. vaginalis grown in a high-iron medium. Ten cDNA clones (three for AP65, one for AP51, and six for AP33) were recognized with polyclonal antiserum or monoclonal antibody raised against these adhesins. No cross-hybridization among cDNAs of the three adhesins was observed in Southern analysis, confirming restriction mapping analysis of representative cDNAs. Southern analysis probed with representative cDNAs of the adhesins indicated multiple copies for each of the three adhesin genes. Northern analysis showed transcripts of 1.8 kilobases (kb), 1.4 kb, and 0.9 kb for AP65, AP51 and AP33, respectively. Consistent with adhesin expression, mRNAs for these adhesins were detected only when parasites were grown in high-iron conditions. Specific antibodies eluted from E. coli expressing recombinant proteins reacted only with the respective parasite adhesins. Recombinant proteins bind to fixed HeLa cells and competed with radiolabeled trichomonad adhesins for binding. Although proteinase activity is required for cytoadherence, recombinant proteins show no detectable proteinase activity. These data show that recombinant proteins from these clones exhibited characteristics of the trichomonad adhesins.

The Trichomonas vaginalis phenotypically varying P270 immunogen is highly conserved except for numbers of repeated elements.

The prominent and phenotypically variable immunogenic protein of Trichomonas vaginalis, termed P270, is present in all isolates. Most, if not all, patients make antibody to the DREGRD epitope contained in the 333 bp tandemly repeating element (TRE). The complete sequence of p270 of a fresh clinical isolate was recently derived (Musatovova and Alderete, Microb Pathogen 1998; 24: 223-39). We hypothesized that the size polymorphisms of P270 were due to the varied number of TREs that comprise a large, central portion of the gene. In this study, we analysed the p270 coding regions of ten representative isolates. It was determined also that the sequence of the TRE of different p270 genes shared > or =99% identity, and individual TREs of the same p270 gene showed them to have identical nucleotide sequences, affirming the highly-conserved nature of this element within each gene. The coding regions upstream and downstream of the central TREs were then generated by PCR amplification using specific primers. The PCR products corresponding to the 5' and 3'-end coding, non-repeat sequences were then subjected to restriction analyses, and the regions were highly conserved for all p270 genes. The complete sequence of two p270 genes showed > or = 99% identity of amino acids at the N- and C-terminal regions of p270, further reinforcing that the reported polymorphisms in Mr of P270 is due to the varying number of TREs and, therefore, the size of the TRE domain. In support of this hypothesis and during these analyses, one isolate, T. vaginalis T016, was discovered which possessed a p270 gene with only one partial repeat unit. Importantly, and as with all other p270 genes, transcription of this single-repeat p270 gene in isolate T016 was confirmed. The start codon for the p270 T016 gene was preceded by the 12 nucleotide consensus Inr promoter-like sequence (TCATTTTTAATA) and possessed a putative transmembrane domain at the carboxy terminus.

Molecular analysis of the gene encoding the immunodominant phenotypically varying P270 protein of Trichomonas vaginalis.

Trichomonas vaginalisis a flagellated protozoan responsible for the most common non-viral sexually transmitted disease. The immunogen P270 was previously found to be up-regulated in expression and to undergo phenotypic variation between surface versus cytoplasmic localization in trichoImonads harbouring a dsRNA virus. In this report, we characterize the entire p270 open reading frame (ORF) and the unknown flanking 5;- and 3;-unique, non-repeat coding sequences of the gene in addition to untranslated regions. Consistent with an earlier report (Dailey & Alderete, 1991, Infect. Immun. 59: 2083-88), a significant portion of the gene consists of a tandemly repeated 333 bp element that contains the sequence coding for the epitope DREGRD detected by murine monoclonal antibody and antibody from the sera of patients. The non-repeat coding regions for the 5;- and 3;-ends were 69 nucleotides (23 amino acids) and 1183 nucleotides (395 amino acids), respectively. Sequencing of repeat elements showed them to be identical, affirming the highly-conserved nature of this element throughout the gene. The start codon was immediately preceded by the 12 nucleotide consensus sequence (TCATTTTTAATA) found in other trichomonad protein-coding genes. A very AT-rich, non-coding region was identified upstream of the p270 ORF. P270 appears to contain a leader sequence at the amino-terminus and transmembrane domain at the carboxy-terminus. No significant homology was found with any reported proteins at either the nucleotide or amino acid level.

Cloning and molecular characterization of two genes encoding adhesion proteins involved in Trichomonas vaginalis cytoadherence.

Cytoadherence to the vaginal epithelium is a critical step in infection by the eukaryotic flagellate Trichomonas vaginalis. Four trichomonad surface proteins (AP65, AP51, AP33 and AP23) mediate cytoadherence. The cDNA encoding the AP65 adhesin was isolated from a phagemid cDNA expression library by screening with antiserum and monoclonal antibody (mAb) raised against the purified trichomonad AP65 protein. Two clones, F11.2 and F11.5, coded for immuno-crossreactive recombinant proteins that possessed functional properties equal to the T. vaginalis AP65 adhesin. Analysis of full-length sequences corresponding to the F11.2 and F11.5 cDNAs revealed that both contained 1701-base open reading frames (ORFs) that encoded proteins of 63 281 daltons and 83 087 daltons, respectively. Comparison of the full-length sequences showed 87% identity at the nucleotide level and 91% identity at the protein level. Restriction-enzyme mapping and Southern analysis reaffirmed the distinctness of the F11.2 and F11.5 cDNAs, indicating that two different AP65 genes (now called ap65-1 and ap65-2) are present in the T. vaginalis genome in at least two copies each. Northern analysis detected high levels of transcript of approximately 1.8 kb for both ap65-1 and ap65-2 genes in trichomonads grown only in high-iron medium, confirming the transcriptional regulation of adhesin synthesis by iron. Homology searches revealed significant similarity (38% amino acid identity and 54% nucleotide identity) to malic enzymes. However, purified malic enzyme and mAb to AP65 crossreactive with malic enzyme neither inhibited cytoadherence of T. vaginalis to host cells nor prevented binding of the trichomonad AP65 to HeLa cells in a ligand assay.