Diabetes screen during tuberculosis contact investigations highlights opportunity for new diabetes diagnosis and reveals metabolic differences between ethnic groups

Type 2 diabetes (T2D) is a prevalent risk factor for tuberculosis (TB), but most studies on TB-T2D have focused on TB patients, been limited to one community, and shown a variable impact of T2D on TB risk or treatment outcomes. We conducted a cross-sectional assessment of sociodemographic and metabolic factors in adult TB contacts with T2D (versus no T2D), from the Texas-Mexico border to study Hispanics, and in Cape Town to study South African Coloured ethnicities. The prevalence of T2D was 30.2% in Texas-Mexico and 17.4% in South Africa, with new diagnosis in 34.4% and 43.9%, respectively. Contacts with T2D differed between ethnicities, with higher smoking, hormonal contraceptive use and cholesterol levels in South Africa, and higher obesity in Texas-Mexico (p < 0.05). PCA analysis revealed striking differences between ethnicities in the relationships between factors defining T2D and dyslipidemias. Our findings suggest that screening for new T2D in adult TB contacts is effective to identify new T2D patients at risk for TB. Furthermore, studies aimed at predicting individual TB risk in T2D patients, should take into account the heterogeneity in dyslipidemias that are likely to modify the estimates of TB risk or adverse treatment outcomes that are generally attributed to T2D alone.

A missed tuberculosis diagnosis resulting in hospital transmission

OBJECTIVE

To find the source of tuberculin skin test conversions among 38 hospital employees on 1 floor during routine testing January-February 2010.

METHODS

Record review of patients at a private hospital during September-December 2009 and interviews with hospital employees. Names of patients from the state tuberculosis (TB) registry were cross-referenced with hospital records for admissions. Mycobacterium tuberculosis genotype results in the county and adjacent counties were examined, and contacts were evaluated for TB infection and disease.

RESULTS

One of the 38 employees, a nurse, was diagnosed with pulmonary TB with a matching M. tuberculosis genotype and drug resistance pattern (isoniazid monoresistant) to those of a county jail inmate also recently diagnosed with pulmonary TB. The nurse had no known contact with that inmate; however, another inmate in his 20's from the same jail had been hospitalized under that nurse's care in October 2009. That young man died, and a postmortem examination result subsequently confirmed TB, which had not been suspected. Exposure to this man with undiagnosed TB could explain the transmission: 87 (27%) of the 318 hospital-based contacts without previous positive tuberculin skin test results were infected, and 9 contacts had active TB.

CONCLUSIONS

This investigation demonstrated M. tuberculosis transmission in a hospital due to a missed diagnosis and nonadherence to national TB infection control guidelines. Routine TB screening of employees allowed early detection of this missed TB diagnosis, facilitating prompt evaluation of contacts. Healthcare providers should suspect TB in symptomatic persons and adhere to TB control policies.

A relevant enzyme in granulomatous reaction, active matrix metalloproteinase-9, found in bovine Echinococcus granulosus hydatid cyst wall and fluid

In addition to the ability of matrix metalloproteinases (MMP) to degrade components of the extracellular matrix and their involvement in pathology-related processes of tissue remodeling, they were recently reported to enhance inflammation by activation of proinflammatory cytokines, or their release from the cell surface. In the work reported here, proteolytic activity previously found for hydatid cysts was further characterized as MMP-9. Active host MMP-9 was found in walls and fluids of bovine hydatid cysts of Echinococcus granulosus in the environment of granulomatous reaction. Pooled walls and fluids of hydatid cysts obtained from infected cattle were processed. Strong proteolytic activity was detected by zymography. The proteolytic fraction was purified by anion exchange and gelatin-agarose affinity chromatography. Major proteinases of the purified fraction were subjected to mass spectrometry and their identities were further confirmed by Western blotting using commercial anti-human MMP-9 monoclonal antibodies. Two proteinases were characterized as latent and active forms of host MMP-9. Using the same antibody for immunoblot, activity was localized, in paraffin-embedded sections of the parasite and the local host environment, to epithelioid and giant multinucleated cells. It is proposed here that MMP-9 is secreted by specialized host cells of monocytic lineage (epithelioid/giant cells) as an effector, in an attempt to digest the persistent foreign body. In vivo activation of MMP-9 suggests its involvement in inflammatory reaction and in the chemotaxis of inflammatory cells to the cyst. However, E. granulosus can deal efficiently with MMP-9. Research is suggested into possible immune evasion mechanisms, including the secretion of an inhibitory molecule.

Prevalence and risk factors for gallstone disease

Gallstone disease is a main public health problem. The overall prevalence data range from 3.9% in the pre-echographic era to 13.7% when ultrasonography was used as a diagnostic tool. This study is aimed to determine the prevalence of gallstone disease in a medium income level population in Lima, as well as the relationship with some risk factors: age, sex, familiar history and obesity. A total of 534 adult men and women from a medium economic level underwent ultrasonographic examination of abdomen for detection of gallstone disease (July 2003). The echographic evaluation was performed by 10 general surgeons trained in ultrasonography. Likewise, 4 risk factors--age, gender, familial history, and obesity--were analyzed. Pearson chi2 test (2-sided) was used with a probability of <0.05 for statistical significance and logistic regression analyses for assessment of confounding factors. The prevalence founded was 15%. Eighty-one of 534 participants had lithiasis. Compared to the age group under 30, the odds ratio for the 31 to 50 years and >50 years of age group was 0.9 and 1.1, respectively. The female-male ratio was 1.07 and the odds ratio 0.8. The prevalence of gallstone disease in people reporting a first-degree relative with lithiasis was 21%, whereas in participants without such a condition, it was 13%. On the other hand, a familial history was present in 38% of the lithiasis group and in 25% of the nonlithiasis group. The odds ratio for familial history was 1.8 (P = 0.01, 95% confidence interval 1.1-2.9). The prevalence of the disease for body mass index <24, 25 to 29, and higher than 30 was 17%, 14% and 13%, respectively. Compared to the reference group (body mass index <24), the other 2 groups (body mass index 25-29 and >30) both had a similar odds ratio, 0.8. Logistic regression analyses showed an odds ratio of 1.9 for familiar history (95% confidence interval 1.1-3.2), whereas the odds ratio of the overweight (body mass index 25-29) and obese group (body mass index >30) when compared to the normal group, BMI <24, was 0.7 and 0.9, respectively. The prevalence data for gallstone disease remain slightly higher than those previously reported. Although the familiar history was the only characteristic with a statistically significant positive relationship with lithiasis, additional studies are needed because few biases could not be completely avoided and some confounding factors were not controlled.

Intraspecific heterogeneity in the mini-exon gene localization of Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis from Colombia

Intraspecific heterogeneity was demonstrated in the mini-exon gene localization from Leishmania (Viannia) panamensis and L. (Viannia) guyanensis. Different karyotypes were detected in human isolates circulating in endemic areas of Colombia. The presence of mini-exon gene sequences on chromosomes of different sizes, ranging from 370 to 800 kb in L. (V.) panamensis and from 500 to 800 kb in L. (V.) guyanensis, was observed and was neither strain nor species specific. In some cases, hybridization with 2 chromosomes in the same strain was observed. The variability of chromosomal localization of mini-exon gene sequences of these 2 species highlights the genetic variability of the Viannia subgenus and the potential utility of the mini-exon gene as a molecular epidemiologic marker.

A 30 year functional follow-up of a neglected congenital clubfoot in an adult: a case report

Neglected congenital clubfoot in adults has been described in literature, but is not common to see adult patients with this orthopaedic disorder in developed countries with 30 years of follow-up. We report an asymptomatic case of neglected congenital clubfoot in an adult, who is incidentally seeking treatment for her 18-month-old son with congenital clubfoot. Although the cosmetic appearance is unacceptable, this mother remarkably has no functional limitations and for this reason she refuses any surgical treatment for her foot. To our knowledge, this is the first report of an untreated congenital clubfoot with 30 years follow-up.

Identification and localization of glutathione S-transferase as a potential target enzyme in Brugia species

Brugia filarial nematodes are pathogenic lymphatic-dwelling parasites that, like other helminths, may modify the host's defense mechanisms by a major detoxification process involving glutathione-binding proteins such as glutathione S-transferases (GSTs). In the present study, soluble extracts of third-stage larvae, adult male and female worms, microfilariae of either B. pahangi or B. malayi or the adult worm excretory-secretory products of B. malayi were used to determine GST activity. These extracts and affinity-purified fractions of B. pahangi adult worms had a specific enzymatic activity when 1-chloro-2,4-dinitrobenzene was used as a substrate. The observance of this enzyme in all life cycle stages of Brugia spp. demonstrates its ubiquitous nature. Lavage of intraperitoneally infected jirds, but not that of uninfected jirds, also showed increased enzymatic activity, suggesting that GST is secreted in vivo. Soluble proteins of both Brugia spp. were strongly recognized by antibodies in sera from rabbits immunized with affinity-purified native GST of Onchocerca volvulus. Immunohistochemical studies localized these proteins in adult worms, demonstrating cross-reactivity between the GST of these two filarial nematodes. The effect of this enzyme on the motility and viability of adult worms, microfilariae, and larvae was tested in vitro using a battery of known GST inhibitors. Of all those tested, ethacrynic acid, N-ethylmalemide, 4-nitropyridine-oxide, or 1-chloro-2,4-dinitrobenzene at micromolar concentrations reduced the viability and motility of microfilariae, third-stage larvae, and adult worms. These results suggest that Brugia GSTs are major metabolic enzymes and may play an important role in the parasite's survival.

Molecular characterization of P-29, a metacestode-specific component of Echinococcus granulosus which is immunologically related to, but distinct from, antigen 5

In this work the characterization of P-29, a novel 29 kDa antigen from Echinococcus granulosus is reported. E. granulosus was identified while looking for parasite antigens distinct from those present in hydatid cyst fluid. A monoclonal antibody (mAb 47H.PS) prepared against protoscolex components revealed that P-29 is localized to the tegument and rostellum of protoscoleces, and to the germinal layer of the cyst, but it is absent in hydatid cyst fluid or adult worm extracts. Several internal fragments of P-29 showed sequence identity to the amino acid sequence encoded by Eg6, a partial gene sequence reported to code for an epitope of antigen 5 (Ag5), one of the major diagnostic antigens of the parasite. We confirmed that Eg6 encodes a sub-fragment of P-29 by mapping the epitope of mAb 47H.PS, and isolating the full length P-29 cDNA. Since Eg6 had been, postulated to encode a fragment of Ag5, we specifically studied the relationship of P-29 and Ag5 by: (i) examining the cross-reactivity displayed by different mAbs; (ii) comparison of their peptide finger prints; and (iii) a comparative study of their diagnostic value. Our results prove unequivocally that P-29 and Ag5 are immunologically related, but different proteins, raising several questions on the current knowledge of Ag5.

Molecular cloning and characterization of a thioredoxin gene from Echinococcus granulosus

The insert of a clone from a lambdagt11 Echinococcus granulosus (Platyhelminth, Cestoda) protoscolex cDNA library, showed an open reading frame whose deduced protein sequence presents a high homology with all described thioredoxins (TRX). The TRX active site (Trp-Cys-Gly-Pro-Cys) is completely conserved. With a monospecific antibody, selected from a total anti-protoscolex sera by the isolated clone, a 12 kDa polypeptide was immunoprecipitated from a protoscolex total protein extract. Furthermore, an antiserum raised against a recombinant EgTRX also recognizes a 12 kDa band in these extracts. The recombinant protein presents TRX activity, using the insulin reduction assay. Finally, a TRX activity was characterized in protoscolex extracts. In all organisms where TRXs were studied, they participate in a cascade of redox exchanges, contributing to the maintaining of cell homeostasis. Considering that the parasitic flatworm E. granulosus is probably submitted to an important oxidative stress due to host defences, EgTRX protein could be involved in the survival strategies of this parasite.

Human isotype antibody responses to an Onchocerca volvulus glutathione S-transferase

Human isotype specific antibody responses to a recombinant pi-class glutathione S-transferase (Ov24) from Onchocerca volvulus were assessed by ELISA, using a large and well-characterized bank sera (n = 238) from an hyper-endemic area of moderate intensity from Sierra Leone. IgG1, IgG4 and IgA responses, but neither IgG2 nor IgE response, to Ov24 were detected in infected subjects. The relationships between Ov24 antibody levels and skin microfilarial density, number of nodules, age, sex, eosinophil counts and clinical sign of reactive and chronic pathology were analysed using Pearson's correlation coefficient. Significant correlations between both IgA and IgG3 antibody levels and age were found (P < 0.01). Although no firm conclusions could be drawn from this study sample regarding the relationships between antibody levels and parasite load or clinical status, a negative correlation (P = 0.06) between Ov24 IgG3 antibody levels and microfilarodermia was found.

Leishmania RNA viruses in Leishmania of the Viannia subgenus

Karyotype analysis of 69 strains of Leishmania belonging to three species of the Viannia subgenus originating from the southeastern and southwestern regions of Colombia revealed approximately 5.3-kb RNAs in four strains of L. braziliensis and also in the World Health Organization reference strain L. guyanensis IWHI/BR/78/M5313. The RNA element in this reference strain and in L. braziliensis strains isolated from cutaneous and mucosal lesions of four patients hybridized with RNA probes prepared from cDNA of the RNA virus present in L. guyanensis strain CUMC-1-1A (LRV1-1). These strains also contained an 80-kD protein that reacted with polyclonal antibody prepared against a recombinant fragment of the coat (capsid) protein of LRV1-1. In addition, another Colombian strain of L. braziliensis was found to contain an approximately 3.5-kb RNA that did not hybridize with LRV1-1 probes. Contrasting with the strains containing the 5.3-kb RNA, a total lysate of this strain did not contain material reactive with antiserum to the capsid protein fragment. All Leishmania containing LRV1-related viruses identified to date have originated in the Amazon River basin. Karyotype analyses and biological characterization of 17 clones obtained from the highly metastatic L. guyanensis strain 5313 revealed retention of the approximately 5.3 kb RNA in all clones and no segregation of the virus with the metastatic trait. The restricted distribution of LRV1-related viruses among some strains of L. braziliensis and L. guyanensis circulating in the Amazon River basin makes these elements potential epidemiologic markers.

Molecular characterisation and localisation of an Onchocerca volvulus pi-class glutathione S-transferase

Glutathione S-transferases (GSTs) constitute a major detoxification mechanism in helminth organisms and are regarded vaccine candidates against helminth infections. Onchocerca volvulus glutathione-binding proteins were purified from the aqueous soluble fraction of homogenised adult females by affinity chromatography on glutathione-agarose. The eluted proteins had a specific GST activity of 1.6 mumol min-1 mg-1. Immunohistochemical studies localised these antigens in the hypodermis, the wall of the seminal receptacle and spermatozoa of adult worms. A lambda gt11 clone was isolated from an expression library of O. volvulus by immunoscreening. Sequence analysis revealed that it encoded a pi-class GST with 60% identity with Caenorhabditis elegans and up to 45% identity with mammalian pi-class GSTs. Antibodies affinity selected with recombinant GST demonstrated cross-reactivity between Litomosoides sigmodontis and O. volvulus GSTs.

[Detection of amastigotes in cutaneous and mucocutaneous leishmaniasis using the immunoperoxidase method, using polyclonal antibody: sensibility and specificity compared with conventional methods of diagnosis]

The indirect immunoperoxidase method was evaluated in 265 biopsies with the purpose of increasing the sensitivity of the diagnostic histopathology of tegumentary lesions caused by subspecies of the Leishmania braziliensis complex. A diagnosis of leishmaniasis was established by parasitological methods (181) or clinical criteria (12) in 193 patients (72.8%). In the latter group of confirmed cases standard histochemistry and immunoperoxidase were compared with direct examination of tissue scraping and culture of lesion aspirates. The detection and localization of amastigotes was more efficient using the immunoperoxidase method (61.3%) than conventional histopathology with hematoxilin and eosin (34.6%) or direct examination of tissue scraping (43.9%). However, culture of lesion aspirates was the most sensitive procedure (89.8%). The efficiency of the immunoperoxidase method was greater in recent lesions, being positive in 75% of cases with less than 3 months evolution, while 55.6%, 37.5%, and 21.1% of cases with lesion evolution of 3-5.9, 6-11, and 12 months or greater, respectively, were positive. The combined use of the direct examination of lesion scraping and immunoperoxidase applied to histological sections of the biopsy from the lesion border allowed an etiologic diagnosis of 72% of confirmed cases. Cross-reactivity was observed with Paracoccidioides braziliensis but not with Mycobacterium leprae, Sporothrix schenckii, or Histoplasma capsulatum.