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PubMed2005

Multiplex PCR detection and species differentiation of orthopoxviruses pathogenic to humans.

A method for one-stage rapid identification of four orthopoxvirus species pathogenic to humans based on multiplex polymerase chain reaction (MPCR) was developed. Five pairs of oligonucleotide primers--one, genus-specific; and the rest, species-specific for variola, monkeypox, cowpox, and vaccinia viruses, respectively--were used concurrently for MPCR assay of orthopoxvirus DNAs. Specificity and sensitivity of the method developed were evaluated using DNAs of 57 orthopoxvirus strains, including the DNAs isolated from human case clinical materials.

Cowpox virus↗

PubMed1998

Gene discovery through expressed sequence Tag sequencing in Trypanosoma cruzi.

Analysis of expressed sequence tags (ESTs) constitutes a useful approach for gene identification that, in the case of human pathogens, might result in the identification of new targets for chemotherapy and vaccine development. As part of the Trypanosoma cruzi genome project, we have partially sequenced the 5' ends of 1, 949 clones to generate ESTs. The clones were randomly selected from a normalized CL Brener epimastigote cDNA library. A total of 14.6% of the clones were homologous to previously identified T. cruzi genes, while 18.4% had significant matches to genes from other organisms in the database. A total of 67% of the ESTs had no matches in the database, and thus, some of them might be T. cruzi-specific genes. Functional groups of those sequences with matches in the database were constructed according to their putative biological functions. The two largest categories were protein synthesis (23.3%) and cell surface molecules (10.8%). The information reported in this paper should be useful for researchers in the field to analyze genes and proteins of their own interest.

Animals↗

PubMed2004

Garden-variety vaccines: antigens derived from transgenic plants.

The discovery of new vaccines can result from deletion of virulence determinants from a specific pathogen or from identification of target antigens that stimulate a protective immune response. Vaccine development will become less empirical as applications of genomics, proteomics and reverse vaccinology are exploited, and new protective antigens will emerge for inclusion in the vaccines of the future. However, production and purification of these new antigens for oral and parenteral use using traditional expression systems, will be expensive and unattractive to vaccine manufacturers who see the vaccine market as economically uninviting. Cost is one of the persistent barriers to deployment of new vaccines to populations that need them most urgently. This factor will inhibit the development and distribution of safe and effective new vaccines against high priority pathogens.

Antigens, Viral↗

PubMed1991

Spectrum and treatment of bacterial infections in cancer patients with granulocytopenia.

Bacterial infections remain a frequent cause of morbidity and mortality in cancer patients with granulocytopenia. In recent years the proportion of patients with gram-positive infections, caused mainly by coagulase-negative staphylococci and viridans streptococci, has increased markedly in many institutions. The precise reasons for this recent change in the epidemiology of infection in cancer patients are as yet not fully ascertained. Although less prevalent, gram-negative infections are still the major threat, since they are associated with higher mortality. What constitutes the optimal empirical antibiotic therapy remains a controversial issue. One should however recognize that the results of one particular study may not be relevant to other institutions where the predominant pathogens and the pattern of antibiotic resistance may be different. In addition, the results of studies using various antibiotic regimens should be compared with caution. However, with these limitations in mind, the results of the most recently published studies support the following recommendations: in patients with nonmicrobiologically documented infections, monotherapy with a third-generation cephalosporin or a carbapenem is a safe alternative to combination therapy. For gram-negative bacteremia, combined therapy with an extended-spectrum beta-lactam antibiotic and an aminoglycoside appears preferable. For gram-positive infections, a specific anti-gram-positive antibiotic is not needed in every patient and can safely be added upon identification of the pathogen in those patients not responding to empirical therapy.

Agranulocytosis↗

PubMed2004

[Traditional and innovative diagnostic tools: when and why they should be applied].

The development of new technological methods surely improves the quality of the Diagnostic Services in Parasitology offered to the National Sanitary Service, however, cost and simplicity have not to be neglected, even when the prime consideration is efficiency. Moreover, the mere fact that something can be done by one of these new approaches does not mean that it should be done that way or that it is most cost-effective to do it that way. A review of diagnostic tools in Parasitology is proposed, to evaluate when and why each of them should be applied. Traditional procedures for the diagnosis of parasitosis are only based on the "direct" recovery and recognition of the parasite, with the microscope as main tool and few other instruments as co-operator. The innovative procedures, recently adjusted on the basis of new scientific knowledge and made possible by the development of the laboratory instrument weapons, can evidence the parasites both directly and indirectly. If it is obvious that the direct identification of a pathogen is more reliable than that indirect, is not so evident what is the most useful direct method, and when it would be better to use indirect diagnostic tools. Advantages and disadvantages of each procedure, cost as well as the purpose of the test (diagnosis, post-treatment, research), and the general condition in which the test have to been applied must be taken into account when we are choosing. In general, we can say that the rationale for their use can be summarised as follows: 1) The macroscopic/microscopic analysis of samples is always recommended (with the exception of samples coming from tissues that need surgery). This "old" procedure allows the identification in 20 minutes of all the parasites present in mixed infections, and the evaluation of the parasite load. It is a cost-effective method which relies ultimately on the skill of the observer to detect and identify parasite stages; 2) Parasite antigen detection is an innovative and expensive immunological diagnostic, which can suffer of sensitivity and specificity. It could be useful to directly diagnose "occult" infections; 3) Parasite DNA/RNA direct detection is an innovative, sensitive and specific procedure, which can also identify sibling species. It is expensive, therefore its use is restricted to reference laboratories; 4) Host antibody detection is an innovative indirect tool to evaluate the presence of a parasite by means the evaluation of the host response to infection. It can suffer of sensitivity and specificity, and the interpretation of the test results may be difficult. It could be applied as first step to evaluate the presence of tissue parasites, whose direct diagnosis would require surgery. Some tests can be performed in well-equipped laboratories; other tests are available through research laboratories. The specimens, appropriately collected and preserved, have always to be processed in security for potential risk of infection hazard, and submitted to tests appropriate to the laboratory's goals, where, therefore, field and research diagnostic tools shouldn't be applied. The test selected for routine use has to be chosen taking into account value and limitations of each method. Reduction in excessive and often unnecessary testing is mandatory, and therefore it is critical for the clinical Parasitology to perform relevant testing while maintaining appropriate quality. To date, the microscopic analysis of samples is the only direct method that allows all identifications in short times, at a reduced cost, independently from geographical origin and peculiar status of the patient. It has to be regarded as the first step in diagnostic procedures for all laboratories. Some molecular techniques have greater sensitivity than traditional methods, but at least at the present time, their costs may well preclude their routine use. It is difficult to know, exactly, where diagnostic Parasitology will be moving in the next few years, although many soothsayers feel very strongly that the area of molecular diagnostics will replace more traditional means. It is also possible that immunological or perhaps cytometric procedures will replace our more standard diagnostic approach; nevertheless they will continue to remain oddities on the outside of the general practice and be confined to a few reference laboratories. As far as semi-automated or automated instruments and robotics-based techniques, they are useful when large numbers of the same test are performed. Supposing that they will enter in our laboratory, that will happen in central facility rather than in each local facility. So, the great interest in using new technological methods to solve old problems probably will have to be seen in the right perspective.

Animals↗

PubMed2026

NF2-related Schwannomatosis Diagnosed Before and After 30 Years of Age: Differences in Disease Presentation and Rates of Positive Genetic Testing.

OBJECTIVE: Characterize pathogenic variants, rates of mosaicism, genetic testing yield, and disease severity among patients with NF2-related schwannomatosis dichotomized by diagnosis before or after the age of 30. STUDY DESIGN: Retrospective analysis. SETTING: Tertiary referral center multidisciplinary NF2 clinic from 2021 to 2024. PATIENTS: Patients with NF2-related schwannomatosis. INTERVENTION: Next-generation sequencing. MAIN OUTCOME MEASURE: Rates of mosaicism, genetic testing rates and yield, and overall disease severity by tumor burden. RESULTS: From 2021 to 2024, there were 32 patients ≥30 years of age and 39 patients diagnosed at younger ages. Patients diagnosed ≥30 years exhibited decreased likelihood of receiving genetic testing (53% vs. 85%; P =0.009) and decreased genetic yield (defined as identification of a pathogenic genetic variant in those undergoing testing; 65% vs. 85%; P =0.20). Both age groups demonstrated similar rates of pathogenic variant type with loss-of-function being the predominant variant detected in 73% vs. 67%, for ≥30 vs. <30 years of age; P =0.90. Those ≥30 years harbored fewer number of average anatomic regions involved by tumor (2.3 vs. 3.4; P <0.001) and decreased total number of tumors (7 vs. 12; P <0.001). CONCLUSIONS: Patients diagnosed with NF2-related schwannomatosis at age ≥30 years exhibited reduced disease severity compared with those diagnosed at a younger age despite harboring similar distributions of genetic pathogenic variants inclusive of loss-of-function pathogenic variants. These observations emphasize the importance of considering patient age in addition to genetic testing for diagnostic framing tailored to patients' biology and clinical context to optimize care in the setting of NF2-related schwannomatosis.

Humans↗

PubMed1994

Molecular genetics of human prion diseases.

Human prion diseases occur in inherited, sporadic and acquired forms. The inherited forms are associated with coding mutations in the prion protein gene and the identification of one of these pathogenic mutations allows definitive diagnosis and has resulted in a widening of the previously recognized phenotypic spectrum of these diseases. Study of acquired prion disease provides evidence for genetic susceptibility to development of disease following treatment with contaminated pituitary hormones. Sporadic prion disease occurs predominantly in individuals homozygous with respect to a common PrP polymorphism at residue 129. The identification of pathogenic PrP alleles and the role of the codon 129 PrP gene polymorphism in determining susceptibility to prion disease provides strong support for the idea that an abnormal isoform of PrP, PrPSc, is the principal constituent of the prion and that its propagation involves direct PrP-PrP interactions which occur most readily between identical PrP molecules.

Alleles↗

PubMed2005

The 18S rDNA sequence of Synchytrium endobioticum and its utility in microarrays for the simultaneous detection of fungal and viral pathogens of potato.

Resting spores extracted from wart (Synchytrium endobioticum)-infected potato tubers were used for DNA extraction and amplification of 18S rDNA. Analysis of the cloned, sequenced fragment revealed high similarity to members of the Chytridiomycota. Using this information, specific oligonucleotide probes were designed and arrayed onto glass slides for detection of the pathogen. Viral sequence information available in the databank was retrieved, or new viral sequences were generated, and used to design probes for specific detection of important quarantine viruses of potato. To determine the sensitivity and specificity of the oligonucleotide probes, total RNA from infected plants was reverse transcribed, labelled with Cyanine 5, and hybridised with the microarray. A significant number of the oligonucleotide probes exhibited high specificity to S. endobioticum, Andean potato latent virus, Andean potato mottle virus, Potato black ringspot virus, and Potato spindle tuber viroid. Hybridisation signals of sub-arrays within slides were reproducible (r = 0.79) with a high correlation coefficient of hybridisation repetitions (0.73). Our results demonstrate the potential of microarray-based hybridisation for identification of multiple pathogen targets, which will find application in quarantine laboratories, where parallel testing for diverse pathogens is essential.

Chytridiomycota↗

PubMedDate not supplied

Emerging intestinal protozoa: a diagnostic dilemma.

Increasing isolation of Cryptosporidium, Cyclospora, and microsporidia from immunocompromised patients with severe diarrhea has prompted study of these organisms. Only recently recognized as human pathogens, they have also been associated with several waterborne outbreaks of diarrhea in immunocompetent individuals. Cryptosporidium and Cyclospora have been shown to be transmitted through fecally contaminated food and water. The mode of transmission for microsporidia is still unclear. While the life cycle and pathogenesis of Cryptosporidium are beginning to be understood, the microsporidia and Cyclospora are less well elucidated. The laboratory diagnosis of these protozoa is difficult. The routine ova and parasites screen does not include screening for them. Many microscopic methods, including wet mounts, modified acid-fast and trichrome stains, and immunofluorescence methods have been shown to be effective screening methods in the hands of experienced microscopists. Enzyme immunoassay and polymerase chain reaction methods also show promise. The proper identification of these pathogens rests with well-trained laboratory personnel. As appropriate treatment differs for each genus, communication between the laboratory and the physician is vital to the recovery of the patient.

Animals↗

PubMed2003

Ultra-rapid detection of Chlamydia trachomatis by real-time PCR in the LightCycler using SYBR green technology or 5'-nuclease probes.

Chlamydia trachomatis infections are among the most common sexually transmitted diseases and of great epidemiological importance world-wide. Identification of this pathogen can be difficult, and it is highly desirable to have a rapid and accurate nucleic acid based detection method. Several commercial PCR test systems are available (e.g. CobasAmplicor, Roche, Mannheim, Germany) but they require post-amplification detection by hybridization resulting in extended work-up time and possible cross-contamination. The objective of our study was to develop a routine diagnostic method for the sensitive, specific and rapid detection of C. trachomatis. The obvious choice is real-time PCR without any post-amplification procedures. The dye SYBR Green I (intercalating in dsDNA) provides a simple and fast real-time PCR in the LightCycler. Specific primer design combined with melting curve analysis allows a reliable and sensitive identification of C. trachomatis. In addition, a new commercial real-time PCR system (RealArt C. trachomatis LC PCR Reagents, artus, Hamburg, Germany) was evaluated, that combines sequence-specific primers and fluorescence-labelled (FRET) 5'-nuclease probes. An internal control integrated in this system detects false negative results and erroneous PCR conditions. All results were compared with the corresponding data from an analysis using the CobasAmplicor system (Roche). (Clin

Adult↗

PubMed1985

Biochemical and immunological characterization of the cell surface of the fish pathogenic bacterium Aeromonas salmonicida.

The identification of lipopolysaccharide as periodic acid-Schiff positive material, present in the membrane fraction of the fish pathogenic Gram-negative bacterium Aeromonas salmonicida, analyzed by SDS-polyacrylamide gel electrophoresis, is shown. Such analysis has revealed several periodic acid-Schiff positive bands and many membrane proteins among which a pathogenicity-related Mr 54000 protein as a constituent of an additional surface layer outside the outer membrane (Evenberg et al., (1982) Biochim. Biophys. Acta 684, 241-248). The latter protein, designated as additional cell envelope protein or ACE protein, has been purified and characterized in our laboratory (Evenberg and Lugtenberg, (1982) Biochim. Biophys. Acta 684, 249-254). Most strains produce both high and low molecular weight lipopolysaccharide species, presumably corresponding with the presence and (virtual) absence, respectively, of an O-antigenic chain. The property to produce high molecular weight lipopolysaccharide can be lost upon subculturing in laboratory growth media and such is greatly enhanced by the prior loss of the ability to produce ACE protein. Lipopolysaccharide and ACE protein were identified as the major antigens. A new polysaccharide-like antigen, designated as PS-antigen, was detected. Moreover, immunological indications for the presence of a lipoprotein in A. salmonicida are described. The surface localization of the antigens was determined by testing whether preadsorption of antisera by intact cells decreased the binding of IgG to these antigens, or decreased the ability of the sera to agglutinate cells. According to these criteria lipopolysaccharide, ACE protein and PS-antigen are the major surface-located antigens. Material cross-reactive with lipopolysaccharide, ACE protein and PS-antigen has been found in a large number of strains. Several lines of evidence indicate the presence of interactions between ACE protein and lipopolysaccharide. Based on these results a molecular model of the cell envelope of virulent A. salmonicida is presented.

Aeromonas↗

PubMedDate not supplied

Investigating on a foodborne outbreak: analysis of the critical points.

The Authors describe an epidemiological survey performed after a cluster of cases of foodborne infection involving several participants at a wedding reception. The aim was to identify the food, the responsible pathogen and any shortcomings in the coordination between the various services and the territorial operating units involved in the outbreak investigation. The investigation involved 149 participants; fifty seven persons (38.3%) had a foodborne illness. The only food item that remained associated with illness after multiple regression analysis was the ricotta cheese (RR 3.58, I.C. 1.,72-7.48 ). The finding of B. cereus in samples of ricotta cheese collected at the dairy food supplier indicate its responsibility for the outbreak but diagnostic certainty could not be achieved as no leftovers were available. Thus, shortcomings in this epidemiological investigation are constituted by: delayed notification, which prevented the acquisition of food samples, lack of a reference laboratory and lack of a specific diagnostic protocols, which prevented the microbiological research for the rapid identification of new pathogens incriminated in foodborne diseases. Finally, environmental and sanitary inspections showed deficiencies in the hygienic measures of food storage, particularly regarding refrigeration and in the HACCP plan that was not properly implemented.

Adolescent↗

PubMed2005

Viral encephalitis: a review of diagnostic methods and guidelines for management.

Viral encephalitis is a medical emergency. The spectrum of brain involvement and the prognosis are dependent mainly on the specific pathogen and the immunological state of the host. Although specific therapy is limited to only several viral agents, correct immediate diagnosis and introduction of symptomatic and specific therapy has a dramatic influence upon survival and reduces the extent of permanent brain injury in survivors. We searched MEDLINE (National Library of Medicine) for relevant literature from 1966 to May 2004. Review articles and book chapters were also included. Recommendations are based on this literature based on our judgment of the relevance of the references to the subject. Recommendations were reached by consensus. Where there was lack of evidence but consensus was clear we have stated our opinion as good practice points. Diagnosis should be based on medical history, examination followed by analysis of cerebrospinal fluid for protein and glucose contents, cellular analysis and identification of the pathogen by polymerase chain reaction (PCR) amplification (recommendation level A) and serology (recommendation level B). Neuroimaging, preferably by magnetic resonance imaging, is an essential aspect of evaluation (recommendation level B). Lumbar puncture can follow neuroimaging when immediately available, but if this cannot be obtained at the shortest span of time it should be delayed only in the presence of strict contraindications. Brain biopsy should be reserved only for unusual and diagnostically difficult cases. All encephalitis cases must be hospitalized with an access to intensive care units. Supportive therapy is an important basis of management. Specific, evidence-based, anti-viral therapy, acyclovir, is available for herpes encephalitis (recommendation level A). Acyclovir might also be effective for varicella-zoster virus encephalitis, gancyclovir and foscarnet for cytomegalovirus encephalitis and pleconaril for enterovirus encephalitis (IV class of evidence). Corticosteroids as an adjunct treatment for acute viral encephalitis are not generally considered to be effective and their use is controversial. Surgical decompression is indicated for impending uncal herniation or increased intracranial pressure refractory to medical management.

Central Nervous System↗

PubMed2001

Staphylococcus aureus agr genotypes with enterotoxin production capabilities can resist neutrophil bactericidal activity.

Staphylococcus aureus pathogenicity is mainly due to the production of a number of secreted and cell surface-associated proteins under the regulation of the agr gene. A region of the agr gene was used to subgroup S. aureus strains according to restriction fragment length polymorphisms. Additionally, strains were subtyped according to the coagulase gene in order to strengthen discriminatory power. Virulence capabilities of agr genotype subgroups were evaluated using an in vitro neutrophil bactericidal assay, which showed that prevalent genotypes were significantly better at evading this primary host defense. Multiplex PCR was then used to detect enterotoxin genes among the genotype subgroups in order to determine possible virulence candidates that enable strains to combat neutrophil killing. The prevalent genotype strains were found to possess higher production capabilities for enterotoxin A than did low-prevalence strains. The significance of enterotoxin A production capabilities in affecting pathogenicity of S. aureus strains was evaluated and found to have a profound effect on neutrophil killing abilities. The use of a large epidemiological database as a tool for subgrouping strains with varying degrees of pathogenicity has allowed the identification of relevant and previously undefined virulence factors that affect a pathogen's capability to overcome host immune defenses.

Animals↗

PubMed2000

Panfungal PCR and multiplex liquid hybridization for detection of fungi in tissue specimens.

A procedure based on panfungal PCR and multiplex liquid hybridization was developed for the detection of fungi in tissue specimens. The PCR amplified the fungal internal transcribed spacer (ITS) region (ITS1-5.8S rRNA-ITS2). After capture with specific probes, eight common fungal pathogens (Aspergillus flavus, Aspergillus fumigatus, Candida albicans, Candida krusei, Candida glabrata, Candida parapsilosis, Candida tropicalis, and Cryptococcus neoformans) were identified according to the size of the amplification product on an automated sequencer. The nonhybridized products were identified by sequencing. The performance of the procedure was examined with 12 deep-tissue specimens and 8 polypous tissue biopsies from the paranasal sinuses. A detection level of 0.1 to 1 pg of purified DNA (2 to 20 CFU) was achieved. Of the 20 specimens, PCR was positive for 19 (95%), of which 10 (53%) were hybridization positive. In comparison, 12 (60%) of the specimens were positive by direct microscopy, but only 7 (35%) of the specimens showed fungal growth. Sequencing of the nonhybridized amplification products identified an infecting agent in six specimens, and three specimens yielded only sequences of unknown fungal origin. The procedure provides a rapid (within 2 days) detection of common fungal pathogens in tissue specimens, and it is highly versatile for the identification of other fungal pathogens.

Adult↗

PubMed1997

Expression of heat shock proteins in chronic pancreatitis: protective or pathogenic roles?

The tissue-distributions of heat shock proteins (HSP) identified by monoclonal antibodies ML-30, TB-78, CA-Str7-1, and MAB 72/73 have been examined in formalin-fixed and paraffin wax-embedded tissues from 10 normal pancreatic specimens and 92 cases of chronic pancreatitis. The chronic pancreatitis cases were divided by probable etiology into alcohol-related, postacute pancreatitis, or idiopathic. The HSP identified by ML-30 and CA-Str7-1 were constitutively expressed, with a regional distribution, by duct and ductular epithelial cells in all normal pancreatic tissues. The HSP detected by ML-30 were expressed uniformly throughout the cytoplasm of the majority of ductular epithelial cells in all cases of chronic pancreatitis, irrespective of suspected etiology, and in the ducts of all but two cases of alcohol-associated chronic pancreatitis. The HSP defined by CA-Str7-1 were identified in the majority of duct or ductular epithelial cells in most of the cases of chronic pancreatitis, although possible differential expression was observed with respect to etiology (ie, there seemed to be less HSP in cases of postalcohol pancreatitis). The HSP identified by TB-78 were not constitutively expressed by normal pancreatic tissues but were found in a few scattered epithelial cells in two of these cases. However, significant expression of these HSP were observed in most epithelial cells in a population of cases regarded as either alcohol-associated (0.05 > p > 0.02) or postacute chronic pancreatitis (0.01 > p > 0.001). The HSP identified by monoclonal antibody MAB 72/73 were either not demonstrable or were expressed at very low levels in both the normal and inflamed pancreatic tissues. Expression of the four groups of HSP molecules appeared to be differentially regulated both in normal pancreatic and in chronic pancreatitis tissues. These differences in expression may indicate different functions in normal tissues, with either a protective or a pathogenic role for these proteins in the diseased state. Our current findings support the hypothesis that expression of certain HSP, particularly those identified by TB-78, may be involved in the pathogenesis of distinct subtypes of chronic pancreatitis. Our data do not suggest that HSP are the primary targets of immune-mediated cytotoxic activity; nevertheless, enhanced expression of these molecules by pancreatic ductular epithelial cells does provide an environment in which increased amounts of endogenous intracellular peptides may be transported to the cell surface, thereby becoming potential targets of immune-surveillance and cell-mediated cytotoxicity. Conversely, HSP may play a protective role in such a manner that selected groups of pancreatic ductular epithelial cells withstand cytotoxic damage of chemical, metabolic, or immune origin, and for significantly increased periods of time than they would otherwise; HSP thereby conserve a population of "reserve" epithelial cells from which pancreatic regeneration might occur. Identification of distinct pathogenic groups, defined according to precise immunohistochemical criteria, might provide the basis of a functional assessment and hence allow development of biologically appropriate strategies for managing individual patients with chronic pancreatitis.

Adult↗

PubMed2006

Control of the C. albicans cell wall damage response by transcriptional regulator Cas5.

The fungal cell wall is vital for growth, development, and interaction of cells with their environment. The response to cell wall damage is well understood from studies in the budding yeast Saccharomyces cerevisiae, where numerous cell wall integrity (CWI) genes are activated by transcription factor ScRlm1. Prior evidence suggests the hypothesis that both response and regulation may be conserved in the major fungal pathogen Candida albicans. We have tested this hypothesis by using a new C. albicans genetic resource: we have screened mutants defective in putative transcription factor genes for sensitivity to the cell wall biosynthesis inhibitor caspofungin. We find that the zinc finger protein CaCas5, which lacks a unique ortholog in S. cerevisiae, governs expression of many CWI genes. CaRlm1 has a modest role in this response. The transcriptional coactivator CaAda2 is also required for expression of many CaCas5-dependent genes, as expected if CaCas5 recruits CaAda2 to activate target gene transcription. Many caspofungin-induced C. albicans genes specify endoplasmic reticulum and secretion functions. Such genes are not induced in S. cerevisiae, but promote its growth in caspofungin. We have used a new resource to identify a key C. albicans transcriptional regulator of CWI genes and antifungal sensitivity. Our gene expression findings indicate that both divergent and conserved response genes may have significant functional roles. Our strategy may be broadly useful for identification of pathogen-specific regulatory pathways and critical response genes.

Antifungal Agents↗

PubMedDate not supplied

Respiratory and systemic mycoses: an overview.

Respiratory and systemic mycoses are globally emerging as a problem of increasing importance in infectious diseases. This is attributed to the growing population of immunocompromised patients due to epidemic outbreak of AIDS or to other factors such as use of immunosuppressive drugs in recipients of organ transplantation. The available evidence has unequivocally established the endemic occurrence of blastomycosis, histoplasmosis and penicilliosis mameffei in India. In fact, pencilliosis marneffei has emerged as a major endemic mycosis of AIDS patients in Southeast Asia. It has manifestations simulating those of histoplasmosis capsulati, and it may spread to other regions with enlarging population of AIDS patients. Comprehensive studies are indicated in order to delineate the endemic areas of the afore-mentioned systemic mycoses. Among the other important systemic mycoses reported from India are aspergillosis, cryptococcosis, candidiasis and zygomycosis. Our current knowledge of the global distribution of systemic mycoses does not depict their true prevalence. It largely reflects the geographic distribution of medical mycologists or other investigators engaged in the study of fungal diseases and their research interests. Invasive aspergillosis has emerged as an important disease in patients with neutropenia and bone narrow transplant recipients, cryptoccosis, penicilliosis marneffei and pneumocystosis in patients with AIDS, fusariosis in patients with leukaemia receiving cytotoxic therapy, zygomycosis in diabetic patients and in patients on defroxamine therapy, and Malasseziafurfur infection in patients on total parenteral nutrition: Opportunistic systemic mycoses due to yeasts and yeast-like fungi have become commoner than those due to filamentous fungi, occupying fourth position in the list of bloodstream pathogens in some centers in USA. Also, their incidence, pattern of clinical presentations and species spectrum have significantly changed, largely due to more frequent and prolonged therapeutic or prophylactic use of antifungal drugs and subsequent development of resistance. Consequently, infections with resistant yeast-like fungi such as C. lusitaniae, C. krusei, C. tropicalis, C. glabrata and Trichosporon ovoides (T. beigelii) have recently been reported with greater frequency. Since respiratory and systemic mycoses have no pathognomonic clinical or radiologic syndrome and mycological diagnostic facilities are restricted to only some of the major metropolitan centres, these diseases may be frequently confused with tuberculosis or other diseases of obscure etiology in India and other developing countries. Greater awareness and a high index of clinical suspicion are important pre-requisites for their diagnosis. Also, active collaboration of internists, pathologists, mycologists and microbiologists is advocated for their expeditous diagnosis and successful management. Further studies should focus on the development of rapid techniques for selective isolation and identification of systemic pathogenic fungi. The problem of antifungal resistance is likely to become more serious in the future as more and more patients with AIDS, bone marrow transplantation and neutropenia will require chemoprophylaxis cover against systemic fungal infections. Thus, it would be of vital importance to intensify search for more potent and less toxic antifungal drugs. It is recognized that an increasing number of people whose life is saved or prolonged due to successful treatment of their underlying diseases fall victim to opportunistic, life threatening systemic mycoses. A great majority of the deaths due to these infections occurs because they remain undiagnosed for want of mycological diagnostic services. In order to cope with the challenge of systemic mycoses, the health authorities of the developing countries are called upon to urgently take necessary measures for establishing a network of diagnostic mycology laboratories.

Developing Countries↗