Significant Improvement in Diagnosis of Hepatitis C Virus Infection by a One-Step Strategy in a Central Laboratory: an Optimal Tool for Hepatitis C Elimination?

The remarkable effectivity of current antiviral therapies has led to consider the elimination of hepatitis C virus (HCV) infection. However, HCV infection is highly underdiagnosed; therefore, a global strategy for eliminating it requires improving the effectiveness of HCV diagnosis to identify hidden cases. In this study, we assessed the effectiveness of a protocol for HCV diagnosis based on viral load reflex testing of anti-HCV antibody-positive patients (known as one-step diagnosis) by analyzing all diagnostic tests performed by a central laboratory covering an area of 1.5 million inhabitants in Barcelona, Spain, before (83,786 cases) and after (45,935 cases) the implementation of the reflex testing protocol. After its implementation, the percentage of anti-HCV-positive patients with omitted HCV RNA determination remarkably decreased in most settings, particularly in drug treatment centers and primary care settings, where omitted HCV RNA analyses had absolute reductions of 76.4 and 20.2%, respectively. In these two settings, the percentage of HCV RNA-positive patients identified as a result of reflex testing accounted for 55 and 61% of all anti-HCV-positive patients. HCV RNA results were provided in a mean of 2 days. The presence of HCV RNA and age of ≥65 years were significantly associated with advanced fibrosis, assessed using the serological FIB-4 index (odds ratio [OR], 5.92; 95% confidence interval [CI], 3.4 to 10.4). The implementation of viral load reflex testing in a central laboratory is feasible and significantly increases the diagnostic effectiveness of HCV infections, while allowing the identification of underdiagnosed cases.

Characterization of hepatitis B virus X gene quasispecies complexity in mono-infection and hepatitis delta virus superinfection

BACKGROUND

Hepatitis delta virus (HDV) seems to strongly suppress hepatitis B virus (HBV) replication, although little is known about the mechanism of this interaction. Both these viruses show a dynamic distribution of mutants, resulting in viral quasispecies. Next-generation sequencing is a viable approach for analyzing the composition of these mutant spectra. As the regulatory hepatitis B X protein (HBx) is essential for HBV replication, determination of HBV X gene (HBX) quasispecies complexity in HBV/HDV infection compared to HBV mono-infection may provide information on the interactions between these two viruses.

AIM

To compare HBV quasispecies complexity in the HBX 5’ region between chronic hepatitis delta (CHD) and chronic HBV mono-infected patients.

METHODS

Twenty-four untreated patients were included: 7/24 (29.2%) with HBeAg-negative chronic HBV infection (CI, previously termed inactive carriers), 8/24 (33.3%) with HBeAg-negative chronic hepatitis B (CHB) and 9/24 (37.5%) with CHD. A serum sample from each patient was first tested for HBV DNA levels. The HBX 5’ region [nucleotides (nt) 1255-1611] was then PCR-amplified for subsequent next-generation sequencing (MiSeq, Illumina, United States). HBV quasispecies complexity in the region analyzed was evaluated using incidence-based indices (number of haplotypes and number of mutations), abundance-based indices (Hill numbers of order 1 and 2), and functional indices (mutation frequency and nucleotide diversity). We also evaluated the pattern of nucleotide changes to investigate which of them could be the cause of the quasispecies complexity.

RESULTS

CHB patients showed higher median HBV-DNA levels [5.4 logIU/mL, interquartile range (IQR) 3.5-7.9] than CHD (3.4 logIU/mL, IQR 3-7.6) (P = n.s.) or CI (3.2 logIU/mL, IQR 2.3-3.5) (P < 0.01) patients. The incidence and abundance indices indicated that HBV quasispecies complexity was significantly greater in CI than CHB. A similar trend was observed in CHD patients, although only Hill numbers of order 2 showed statistically significant differences (CHB 2.81, IQR 1.11-4.57 vs CHD 8.87, 6.56-11.18, P = 0.038). There were no significant differences in the functional indices, but CI and CHD patients also showed a trend towards greater complexity than CHB. No differences were found for any HBV quasispecies complexity indices between CHD and CI patients. G-to-A and C-to-T nucleotide changes, characteristic of APOBEC3G, were higher in CHD and CI than in CHB in genotype A haplotypes, but not in genotype D. The proportion of nt G-to-A vs A-to-G changes and C-to-T vs T-to-C changes in genotype A and D haplotypes in CHD patients showed no significant differences. In CHB and CI the results of these comparisons were dependent on HBV genotype.

CONCLUSION

The lower-replication CHD and CI groups show a trend to higher quasispecies complexity than the higher-replication CHB group. The mechanisms associated with this greater complexity require elucidation.

Dynamics of dermatophytosis frequency in Mexico: an analysis of 2084 cases

We analysed 15,101 biological samples from patients presenting with superficial mycoses who attended outpatient services over a 10-year period. Scale samples were processed for direct microscopic examination with 15% KOH and cultured on Sabouraud glucose agar plus chloramphenicol and cycloheximide. Laboratory examination confirmed 4,709 cases of superficial mycosis (31.18%), of which 2,084 (44.26%) were dermatophytoses. The species most frequently encountered was Trichophyton rubrum (71.2%), followed by T. tonsurans (6.9%), T. mentagrophytes (5.5%), Microsporum canis (4.5%) and Epidermophyton floccosum (1.3%). The most frequent clinical form of dermatophytosis was tinea unguium (59.9%), followed by tinea pedis (24.5%). We demonstrate that the number of cases of T. rubrum is increasing in Mexico.

[Detection of Coccidioides immitis infection in Coahuila, Mexico]

Coccidioidomycosis is a mycosis firstly pulmonar caused by Coccidioides immitis; it can be disseminated to central nervous system, bones and skin, principaly. In Mexico, the real frequency of the disease is unknown. The aim of this work was to determine, by skin test and by serology, the infection cases by C. immitis in twelve communities (10 rural and two urban), attended in the Hospital Rural No 79 at the Instituto Mexicano del Seguro Social (IMSS) from the Coahuila State, Mexico. Six hundred and sixty eight adult individuals of both sexes were studied, to whom 0.1 ml of coccidioidin by intradermal route was applied; 72 h after, the induration diameter was measured. One hundred eighty individuals were selected and seric anti-C. immitis immunoglobulins levels were determined by ELISA. Six hundred twenty one individuals (93%) were positive to coccidioidin, the frequency was much higher than that previously reported in Coahuila. From 180 sera studied, the means of optical density (OD) were: IgG1, 1.55; IgG2, 0.94; total IgG, 0.33; IgG3, 0.29; IgG4, 0.27; IgM, 0.08. The values of IgG1, IgG2 and IgM compared with the other immunoglobulins were statistically significant. The high values of IgG1 and IgG2 suggest frequent contact with the antigen, and probable cases of undiagnosed disease.

[Immunoglobulins in patients with Nocardia brasiliensis actinomycetoma]

Considering that some authors have reported an increasing of some immunoglobulins in actinomycetoma patients, in this study we propose to determine differential production of IgG1, IgG2, IgG3, IgG4 and IgGM in 25 patients with actinomycetoma and 25 healthy individuals from a mycetoma endemic area. Immunoglobulins were determined by ELISA technique. To sensibilize the plates, six Nocardia brasiliensis antigens were used: a crude antigen denominated NB and five derivatives (NB2, NB4, NB6, NB8 and NB10) obtained by their isoelectric point. Results showed that all IgG subclasses were higher in the patients' sera than in control sera, with a maximal difference to IgG3 and IgG4. To the latter subclass, six antigens were highly reactives. IgM levels were similar in both groups. As it occurs in other infections, in the actinomycetoma pathogenesis probably participate the increase or deficiency of a determined immunoglobulin class, as well as the relationship between different subclasses.

Fungal peritonitis in 15 patients on continuous ambulatory peritoneal dialysis (CAPD). Fallberichte. Pilz-Peritonitis bei 15 Patienten mit ambulanter Dauerperitonealdialyse (CAPD)

Peritonitis is a frequent complication in patients with chronic renal failure on continuous ambulatory peritoneal dialysis (CAPD) treatment. The aim of this study was to know the prevalence of fungal peritonitis on patients undergoing CAPD, and to determine the antifungal susceptibility pattern of the identified isolates. Samples of the peritoneal dialysis fluid from 165 patients on CAPD treatment with peritonitis manifestations were submitted to mycological study (direct microscopic examination, culture and antifungal susceptibility test). Ten Candida isolates were identified, being C. albicans and C. parapsilosis the most common species. From isolates obtained, three species (C. albicans, C. parapsilosis, and C. guilliermondii) presented itraconazole resistance while C. glabrata was resistant to both itraconazole and ketoconazole. Aspergillus fumigatus was associated to peritonitis in three cases and Acremonium sp. in two.

An Imported Case ofBlastomyces DermatitidisInfection in Mexico

Blastomycosis is an acute or chronic primary infection of the respiratory system, endemic in North America (United States of America and Canada), Africa and Asia. We report a case in Mexico, in a three years old child who had been born in California and lived in Chicago, U.S.A. The patient presented pulmonary symptoms prior to development of a skin ulcer. Blastomyces dermatitidis was identified by mycological and molecular procedures. The patient was successfully treated with amphotericin B, oral ketoconazole and itraconazole.

Effectiveness of terbinafine in the eradication of Microsporum canis from laboratory cats

In this study, the coats of 20 cats with no dermatophytosis lesions were sampled for colonization by Microsporum canis, which was isolated in 45% of cases. All cats were treated with oral terbinafine for 3 weeks. The drug was administered orally at a daily dosage 8.25 mg kg-1. Mycologic status was assessed at the end of the treatment; and after follow-up at 2 days, and 4 and 9 weeks. The final evaluation revealed a complete mycologic cure of all cats by obtaining negative cultures, thereby demonstrating that terbinafine is an effective method of eradication of dermatophyte colonization.

[Study of 50 patients with sporotrichosis. Clinical and laboratory assessment]

Because sporotrichosis is the most frequent subcutaneous mycosis in Mexico and the clinical aspect is not always characteristic, the aim of this study was to evaluate laboratory diagnosis techniques. Fifty patients with clinical diagnosis of subcutaneous sporotrichosis were studied including clinical and epidemiologic data. Metabolic antigen was used to elicit delayed hypersensitivity skin reaction in all patients. Exudate was plated on Sabouraud agar and biopsy material was submitted to indirect immunofluorescence and histopathology. Results showed that sporotrichosis frequency was higher in women (62%), in children and adolescents under 20 years of age (34%) and adults older than 50 years of age (28%). Disease was predominant in farmers (44%) followed by housewives (30%). Lymphangitic form accounted for 82% of cases and these were localized in upper limbs (54%). In 66% of cases, histopathology showed S. schenckii yeasts; hypersensitivity skin reaction was positive in 76% and culture in 94%. By indirect immunofluorescence, parasitic elements were demonstrated in all patients corresponding to both sensitivity and specificity 100%. In this work, indirect immunofluorescence was the most efficient sporotrichosis diagnostic method followed by culture, hypersensitivity skin reaction, and histopathologic study.

[Identification and typing of yeast isolates from hospital patients in Mexico City]

Nosocomial yeast infections have become a major cause of morbidity and mortality in immunocompromised patients. This study presents the frequency of yeasts isolated from different biological products from a Mexico City hospital's patients during one year. C. albicans was isolated in 72.3% of patients, followed by C. glabrata (13.4%) and C. parapsilosis (8%). Twenty different morphotypes were identified and the serotype B was the most frequent (79%).

Frequency of Cryptococcus species and varieties in México and their comparison with some Latin American countries

Cryptococcosis frequency is increasing in Mexico. Few epidemiologic and clinical surveys exist even though 10-15% of patients with AIDS develop this mycosis. To know the situation about the prevalence and etiological agents of cryptococcosis in our country, a study including isolated Cryptococcus spp. strains took place from 1989 to August 1998. A total of 211 Cryptococcus spp. strains obtained from patients of diverse hospital centers in Mexico City were studied. This study describes cryptococcosis epidemiological data, in our country. C. neoformans was the dominant isolation (97.15%), followed by two C. albidus isolation and one C. uniguttulatus isolation. 92.5% of the strains was isolated from cerebral spinal fluid and the remaining were from bone marrow, blood, ganglion, sputum, bronchial lavage and liver biopsy. AIDS was the principal opportunistic factor (85%). Strains were found prevails in males (87.3%). It was found that the age groups where the disease appears most frequently are in the fourth (37.5%) and third (33.8%) decade of life. Finally, the isolation frequency of the C. neoformans var. neoformans (vn) and var. gattii (vg) obtained in this study (vn 86.7%) and vg 10.4%) was compared with the ones registered in Argentina (vn 97.6%, vg 2.4%); Brazil (vn 83.3%, vg 15.8%); Cuba (vn 97.6%, vg 2.4%); Paraguay (vn 0%, vg 100.0%); Puerto Rico (vn 100.0%, vg 0%) and Venezuela (vn 66.7%, vg 29.6%).

Case report: cutaneous penicilliosis due to Penicillium chrysogenum

A case of cutaneous penicilliosis in a young man, without immunological compromise is reported. The lesions in the neck were characterized by two exudative reddish-purple pruriginous and painless spots. Penicilliosis was diagnosed after serial laboratory studies based on the observation of hyphae by direct microscopic examination and histopathology. Cultures of the tissue obtained from the lesions, developed mould colonies with typical conidia of Penicillium chrysogenum, which was thermotolerant at 37 degrees C. The treatment with itraconazole was successful, and 15 days after cessation of therapy, no recurrence of infection was observed. The epidemiology of this type of mycosis is commented upon, as well as the rarity of infections produced by Penicillium, even as opportunistic pathogens. The isolation of P. chrysogenum from skin lesions is exceptional.

Detection and expression of corticosteroid binding protein gene in human pathogenic fungi

Participation of steroid hormones in the growth of several fungal species has been widely reported. The aim of the present study was to detect the presence and expression of the corticosteroid binding protein (CBP) gene in different pathogenic fungal isolates from human clinical specimens. Genomic DNA and total RNA were obtained from six different pathogenic fungal species and submitted to Southern blot and Reverse Transcription-Polymerase Chain Reaction respectively. The results indicated that all the fungi studied presented and expressed CBP gene. The sequence of a PCR product of CBP gene fragment corresponding to the carboxyl terminal region in Trichophyton mentagrophytes, which presented the highest CBP expression, showed an identity of 98% as compared to the previously reported gene sequence from Candida albicans. The overall results indicate that CBP is a highly conserved gene in fungi and suggest that steroid hormones should play an important physiological role in these eukaryotic organisms.

How often are dermatophytes present in apparently normal versus scaly feet of children?

The purpose of this investigation was to find out how often pathogenic dermatophytes are found in apparently normal versus scaly feet of children. In this prospective protocol, we studied 100 patients, 2 to 12 years of age, consulting for plantar and/or interdigital scaling with or without erythema, maceration, and pruritus, and 100 controls with apparently healthy feet. Direct microscopic examination (KOH) and mycologic culture (Mycosel) of skin scrapings were performed from the lesions of patients and from the soles and interdigital folds of controls. Mean age of patients and controls was 7 years 7 months (SD = 3 years 2 months). Scaling was present in 100% of patients with a mean time of evolution of 8.9 months (SD = 16.3 months). Shoes fashioned from man-made material were significantly more frequently used by patients than by controls (chi 2(df = 1) = 9.4; p = 0.002). Pathogenic dermatophytes were present in the soles and/or interdigital webs of 21 patients and 7 controls. Not all foot scaling in children, pruritic or not, is associated with dermatophytes. Dermatophytes may be present on the apparently healthy feet of children.

Cryptococcus neoformans var. gattii among patients with cryptococcal meningitis in Mexico. First observations

A retrospective study of 20 patients with cryptococcal meningitis and their isolated strains was performed. Cryptococcus neoformans var. neoformans was recovered from 14 (70%) cases, and var. gattii was recovered from six (30%) patients. Twelve patients had AIDS (all carrying var. neoformans), two had other diseases (one with var. neoformans and one var. gattii) and there was no identifiable underlying disease in six (one var. neoformans and five var. gattii). Fourteen patients (11 var. neoformans and three var. gattii) resided in the Mexico City area, where a temperate climate is prevalent, and there were six cases (three var. neoformans and three var. gattii) from states with a tropical/subtropical climate. Although there was no significant statistical difference between the two varieties, the fatal outcome was higher in patients with var. neoformans. The disease caused by var. gattii strains was characterized by a higher opening pressure, more inflamatory changes of CSF and a longer clinical course (delayed clinical and mycological cure). Cryptococcus neoformans var. gattii is a significant cause of cryptococcal meningitis in patients without underlying diseases in Mexico.

Isolation of Cryptococcus neoformans var. neoformans from bird droppings, fruits and vegetables in Mexico City

The presence of Cryptococcus neoformans in various natural sources, such as bird droppings, fruits and vegetables, was investigated. A total of 711 samples were analyzed; C. neoformans var. neoformans was isolated from seven out of 74 bird droppings (9.5%), with parrots as one of the most significant sources. Fruits were positive in 9.5% of the 169 samples studied, specially citrus fruits, particularly grapefruit, in which the highest frequency was found. From the 468 vegetable samples, only 20 were positive (4.2%). It is emphasized that five of the positive vegetables species are autochthonous to Mexico: avocado (Nectandra salicifolia), beet (Beta vulgaris var. quinopodiace), chayote (Sechium edule), stringbean (Cassia sp), and nopal (Opuntia ficus-indica).

Isolation of Cryptococcus neoformans from pigeon (Columba livia) droppings in Mexico City

To determine the ecological and epidemiological significance of pigeon excrement in cryptococcosis in Mexico City, 251 samples of pigeon droppings were studied. These were collected from houses, public buildings, churches, parks and pigeon nests. Each sample was suspended 1:10 in isotonic saline solution and then cultured in Staib medium. Identification of Cryptococcus neoformans was performed based on the development of brown-coloured colonies and the presence of encapsulated yeasts. Of 251 samples, 52 (20.7%) were positive for Cr. neoformans. The highest frequency was observed in droppings from public buildings (31.2%), followed by churches (22.0%) and houses (13.3%). No significant differences in isolation frequency were observed between fresh or dried excrement. All isolates obtained were Cr. neoformans var. neoformans. As in other studies on Cr. neoformans from pigeons, performed in other countries, these frequency data are considered 'normal'. The results, however, accentuate the potential risk of cryptococcosis acquisition, especially now that cryptococcosis frequency is increasing in Mexico, mainly in AIDS patients.

Dermatophytoses in Mexico City

We analysed 2350 biological samples from patients with a clinical diagnosis of superficial mycoses who attended outpatient services over a 7-year period. Samples of scales were processed by direct microscopic examination with 15% KOH and cultured on Sabouraud glucose agar with chloramphenicol and cycloheximide. Laboratory examination confirmed dermatophytosis in 860 (36.6%) cases, of which 80.9% were caused by Trichophyton rubrum. The most frequently observed dermatophytoses were tinea unguium (60%) and tinea pedis (25.6%). In agreement with previous observations, we demonstrate that T. rubrum continues to increase in Mexico.

[Exoenzymes of dermatophytes isolated from acute and chronic tinea]

The presence of five enzymes (deoxyribonuclease, elastase, lipase, caseinase and hemolysin) in 76 strains of dermatophytes 47 of Trichophyton rubrum, 10 of T. mentagrophytes, five of T. tonsurans, 10 of Microsporum canis and four of Epidermophyton floccosum) isolated from 30 cases of acute dermatophytosis and from 46 chronic ones was determined by a qualitative plate assay; in the same way, the presence of these five enzymes with the acute and chronic dermatophytosis was correlated. It was observed that three of the enzymes were produced by the strains with a meaningful frequency; deoxyribonuclease was produced by 84.2% of the strains; elastase by 82.9%; and lipase by 65.8%. In T. rubrum the DNase was produced in 100% of strains. DNase and elastase were related to fungi which caused acute or chronic dermatophytosis in 93.3/78.2% and 96.6/74% respectively. On the other hand, lipase was present in 76% of strains, the ones that caused the chronic infections.

[Cicatricial, antibacterial and antimycotic effects of tepescohuite in experimental animals]

The cicatricial and antibacterial effects of the sterile powder of the barks of tepescohuite (Mimosa tenuiflora), 2% mupirocin ointment, and 0.9% saline were compared. The experiment was performed in rabbits with chemically induced burns clinically, histopathologically, bacteriologically, and mycologically controlled. No statistically significant difference was found among the three treatment modalities. Due to the potentially hepatotoxic effects and low therapeutic efficacy of tepescohuite it should not be used in human beings.

Dermatophytes isolated from laboratory animals

In order to determine the presence of dermatophytes in healthy skin, 200 animals from the animal house of Faculty of Medicine, U.N.A.M., were studied; these were 50 rats, 50 rabbits, 50 mice, and 50 guinea pigs. Out of these 200 animals, 29.5% had positive isolation of Trichophyton mentagrophytes, var. lacticolor. The frequency variation was: rats 68%; rabbits, 36%; mice, 8%; and guinea pigs, 6%. Male rats and male rabbits, had the higher incidence of positives. The epidemiologic repercussion of these and the significance to use these animals in biomedical investigation is discussed.

Vaginal candidosis. Opportunistic factors and clinical correlation in 600 patients

Vaginal exudates were taken from 600 new patients of the gyneco -obstetrics outpatient clinic. Candida was isolated from 261 patients, 134 (22.3%) of which had this yeast as a component of the normal flora, and in 127 (21.2%) it was considered as a pathogen. The most frequent symptoms in the last group were vaginal discharge, erythema and pruritus. Pregnancy was the most frequent opportunistic factor, followed by the association of pregnancy and malnutrition, and anemia. Vaginal candidosis was more frequent in patients of the medium socio-economical stratum. The species of Candida isolated were C. albicans (67.7%), C. tropicalis (18.8%), C. stellatoidea (8.7%), C. pseudotropicalis (2.4%), C. parakrusei (1.6%) and C. guillermondi (0.8%).

[Study of the pathogenicity of Conidiobolus coronatus in experimental animals]

The pathogenicity of a strain of Conidiobulus coronatus isolated from Aenolamia postica was investigated in 152 mice, 42 guinea pigs and 47 hamsters. Four routes of inoculation were used: intraperitoneal, subcutaneous, intratracheal and scarification in the oral mucosa. Each animal was inoculated 3 times at 3 week intervals. Animals were sacrificed at 1, 8, 15, 45 of 225 days after the first inoculation. Observations of macroscopic lesions (nodules, abscesses, adhesions, etc.) direct examinations, cultures and histopathological studies of different tissues were performed. The aforementioned lesions of tissue were the most frequently found and all of them were resolved by spontaneous cure. The animals inoculated intraperitoneally and subcutaneouslly presented the highest number of postive results. The histopathological features at the 1st and 8th days after inoculation showed an acute inflamatory infiltrate with well preserved fungus filaments; at the 15th day granulomas with giant cells were observed containing fragmented and disintegrated fungal hyphae; at the 45th and 225th days a fibrosis reaction was observed and no fungal filaments, could be found. In no animal was rhinoentomophthoromycosis never reproduced, and according to these results it is considered that either this strain is not a pathogen or its pathogenicity is very low.

[Otomycosis]

From 163 patients with clinical diagnosis of otomycosis, only 72 were confirmed by the mycological laboratory. No difference was noticed regarding the age and sex of patients. The clinical symptoms were the break of the timpanic membrane, secretion and fungal colonies in one side. Most of our patients had more than one year of evolution. The more common causative agent was Aspergillus and quite frequently it were present non-pathogenic bacteria. The local treatment with a solution containing vioform with salicilic acid was successful in the 82% of cases.