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Biomedical subjects

J Guarro

Publications and source records attributed to J Guarro.

At least 19 recordsLinked to original sources

Characterisation of Aeromonas spp. isolated from frozen fish intended for human consumption in Mexico.

A total of 82 strains of presumptive Aeromonas spp. were identified biochemically and genetically (16S rDNA-RFLP). The strains were isolated from 250 samples of frozen fish (Tilapia, Oreochromis niloticus niloticus) purchased in local markets in Mexico City. In the present study, we detected the presence of several genes encoding for putative virulence factors and phenotypic activities that may play an important role in bacterial infection. In addition, we studied the antimicrobial patterns of those strains. Molecular identification demonstrated that the prevalent species in frozen fish were Aeromonas salmonicida (67.5%) and Aeromonas bestiarum (20.9%), accounting for 88.3% of the isolates, while the other strains belonged to the species Aeromonas veronii (5.2%), Aeromonas encheleia (3.9%) and Aeromonas hydrophila (2.6%). Detection by polymerase chain reaction (PCR) of genes encoding putative virulence factors common in Aeromonas, such as aerolysin/hemolysin, lipases including the glycerophospholipid-cholesterol acyltransferase (GCAT), serine protease and DNases, revealed that they were all common in these strains. Our results showed that first generation quinolones and second and third generation cephalosporins were the drugs with the best antimicrobial effect against Aeromonas spp. In Mexico, there have been few studies on Aeromonas and its putative virulence factors. The present work therefore highlights an important incidence of Aeromonas spp., with virulence potential and antimicrobial resistance, isolated from frozen fish intended for human consumption in Mexico City.

Aeromonas↗

Molecular typing of clinical and environmental isolates of Scedosporium prolificans by inter-simple-sequence-repeat polymerase chain reaction.

Invasive infections by Scedosporium prolificans have increased alarmingly in recent years, mainly in immunosuppressed patients. The epidemiology, pathogenesis and the natural habitat of this pathogen are practically unknown. Isolates of S. prolificans were distinguished from one another by inter-simple-sequence-repeat (ISSR) fingerprinting, a technique based on the high degree of polymorphism of the multisatellite genetic markers used. This technique was found useful for typing 84 isolates of S. prolificans from different countries and sources. The assemblage of S. prolificans isolates tested was extremely diverse, with 35 genotypes present. Several patients were found to have been infected or colonized by more than one strain. Overall, this technique facilitates the epidemiological study of S. prolificans infection.

Australia↗

Interlaboratory evaluation of the Etest for antifungal susceptibility testing of dermatophytes.

A three-site interlaboratory reproducibility evaluation of the Etest concentration gradient strip method for testing antifungal susceptibilities was conducted using 30 strains of dermatophytes exposed to strips loaded with ketoconazole (KTZ), itraconazole (ITZ), amphotericin B (AMB) and fluconazole (FCZ). Etest minimal inhibitory concentrations were compared with those obtained using a broth microdilution method. All isolates produced clearly detectable growth at 28 degrees C within 72-96 h for reading with the Etest method. The highest interlaboratory agreement between Etest and the microdilution method was shown with FCZ (94%), and the lowest was seen with KTZ (60%). Overall, agreement between the Etest and microdilution method was variable. It was excellent for AMB (97%), good for ITZ (80%) and KTZ (77%), and low for fluconazole (27%).

Antifungal Agents↗

A DNA probe specific for Aeromonas colonies.

Members of the genus Aeromonas are important enteropathogens. Commercial identification systems are often unable to correctly identify Aeromonas strains and misidentification as Vibrio spp. is common. A digoxigenin-DNA probe based on a 237 bp of the glycerophospholipid-cholesterol acyltransferase gene has been tested in a colony hybridization assay. The probe hybridized with all Aeromonas species tested (n = 16) but not with strains of other enteropathogenic bacteria (n = 20). The probe allowed the unequivocal identification of Aeromonas in primary isolation media within 36 h.

Acyltransferases↗

Subcutaneous infection by Microsporum gypseum.

We report a case of subcutaneous infection caused by the dermatophyte Microsporum gypseum in an immunocompetent host. The patient acquired the infection in the knee through a traumatic inoculation of a splinter. To our knowledge this is the first case of subcutaneous infection caused by this fungus.

Adult↗

Comparison of the virulence of Scedosporium prolificans strains from different origins in a murine model.

Scedosporium prolificans is an emerging opportunist fungus that causes different types of infections in immunocompetent and immunosuppressed people. These infections show an irregular geographical distribution and, generally, disseminated systemic infections are noticed only in specific countries. This study used a murine model of disseminated infection by this fungus to assess if strains from different origins have different virulence. Two strains from each of four different sources (disseminated infection, localised infection, asymptomatic cystic fibrosis patients and the environment) were tested. Two strains of S. apiospermum of clinical origin were also included in the study; these were clearly less virulent than those of S. prolificans. The S. prolificans strains tested were classified in three groups according to their virulence. The groups with higher and lower virulence were represented by only one strain each, and the intermediate group contained six strains. No significant differences were found between the strains from different geographic areas or different forms of disease.

Animals↗

Cytological and microbiological findings in guttural pouch lavages of clinically normal horses with head restraint.

OBJECTIVE: To evaluate the cytological and microbiological contents of guttural pouch washes of ten randomly selected horses restrained so as to prevent them lowering their heads, and to assess the possible effects on the guttural pouch environment in these horses. PROCEDURE: Cytological and microbiological studies were performed on guttural pouch washes of ten clinically normal horses restrained in a standing position so as to prevent them from lowering their heads below normal, as would happen during transportation on long journeys. They were restrained for 12 or 24 h and cytological, bacteriological and mycological findings in guttural pouch washes were recorded. RESULTS: The cytological gradings and neutrophil concentrations of guttural pouch washings were higher in horses that had their heads restrained for a longer period. Washings from these horses were more likely to contain cultivable bacteria and were the only washes yielding potentially pathogenic bacterial species. CONCLUSION: Variation in the cytological differential counts and bacterial cultures of guttural pouch lavages may be found in clinically normal horses which have had their heads restrained in an elevated position for periods from 12 to 24 h. This should be considered when examining this site and care must be taken when interpreting cytology of guttural pouch lavages in samples taken after transportation for more than 12 h. Restriction of head movement could also affect the normal pouch enviroment and predispose it to disease.

Animals↗

Use of the sensititre colorimetric microdilution panel for antifungal susceptibility testing of dermatophytes.

The Sensititre YeastOne antifungal panel was used to test 49 dermatophytes belonging to the species Epidermophyton floccosum, Microsporum gypseum, Microsporum canis, Trichophyton tonsurans, Trichophyton rubrum, and Trichophyton mentagrophytes. The MICs of four antifungals obtained with the Sensititre YeastOne antifungal panel were compared with those obtained by the reference NCCLS microdilution method. The levels of agreement between the two methods (<or=2 dilutions) were 81.6% with amphotericin B, 87.7% with itraconazole, 67.3% with fluconazole, and 69.4% with ketoconazole.

Amphotericin B↗

Effect of inoculum form on in vitro antifungal susceptibilities of Aspergillus spp.

The effect of inoculum form, i.e. ungerminated conidia, germinated conidia and hyphae on the in vitro antifungal susceptibility of 12 strains belonging to Aspergillus spp. was compared using a broth microdilution method. The isolates were tested three times on different days against amphotericin B, itraconazole and ketoconazole. There were no significant differences between MICs obtained with the three types of inoculum (P > 0.05) for any antifungal tested. The degree of reproducibility of the tests was high (>or=75%) for all antifungals with each type of inoculum, except for itraconazole (58.3%) when the inoculum was prepared with ungerminated conidia.

Amphotericin B↗

In vitro activities of four novel triazoles against Scedosporium spp.

In order to develop new approaches to the treatment of the severe and usually fatal infections caused by Scedosporium spp., the in vitro antifungal activities of four novel triazoles (posaconazole, ravuconazole, voriconazole, and UR-9825) and some current antifungals (amphotericin B, ketoconazole, itraconazole, and nystatin) were determined. The latter group was clearly ineffective against the two species tested. The four new antifungals showed activity against Scedosporium apiospermum, and UR-9825 and voriconazole were active against S. prolificans.

Antifungal Agents↗

In vitro activities of 10 antifungal drugs against 508 dermatophyte strains.

We have tested 508 strains belonging to 24 species of dermatophytes against 10 antifungal drugs following mainly the NCCLS (M38-P) standard for filamentous fungi. However, several important factors, such as the temperature (28 versus 35 degrees C) and time of incubation (4 to 10 days versus 21 to 74 h), have been modified. The antifungals used were itraconazole, ketoconazole, miconazole, clotrimazole, voriconazole, terbinafine, amphotericin B, fluconazole, UR-9825, and G-1. In general, with the exception of fluconazole and G-1, all antifungals were shown to be highly effective.

Antifungal Agents↗

In vitro antifungal activities of the new triazole UR-9825 against clinically important filamentous fungi.

We used a modified reference microdilution method (the M-38P method) to evaluate the in vitro activities of the new triazole UR-9825 in comparison with those of amphotericin B against 77 strains of opportunistic filamentous fungi. UR-9825 was clearly more active than amphotericin B against all fungi except Fusarium solani and Scytalidium spp. Notably, UR-9825 had low MICs for Aspergillus fumigatus and Paecilomyces lilacinus (MICs at which 90% of isolates are inhibited, 0.125 microg/ml for both species).

Antifungal Agents↗

Cutaneous infection caused by Aspergillus ustus, an emerging opportunistic fungus in immunosuppressed patients.

We report a case of primary cutaneous infection by the emerging fungus Aspergillus ustus in an immunosuppressed patient after a domestic accident. The patient failed to respond to itraconazole and died before receiving a new treatment with amphotericin B. There have been eight other cases reported since 1973, and only two patients survived the infection. In vitro susceptibility testing of seven antifungal drugs showed that terbinafine and the new azole derivative UR-9825 were the most active against this fungus.

Aged↗

Phaeohyphomycotic cyst caused by Colletotrichum crassipes.

A case of phaeohyphomycosis is reported in a male renal transplant recipient with a nodular lesion in the right leg who was treated with immunosuppressing drugs. The lesion consisted of a purulent cyst with thick walls. The cyst was excised surgically, and the patient did not receive any antifungal therapy. One year later he remains well. Histological study of the lesion showed a granulomatous reaction of epithelioid and multinucleate giant cells, with a central area of necrosis and pus. Fontana-Masson staining demonstrated the presence of pigmented hyphal elements. The fungus Colletotrichum crassipes was grown in different cultures from the cyst. The in vitro inhibitory activities of eight antifungal drugs against the isolate were tested. Clotrimazole and UR-9825 were the most active drugs. This case represents the first known reported infection caused by this rare species.

Adult↗

Comparison of the minimum fungicidal concentration of amphotericin B determined in filamentous fungi by macrodilution and microdilution methods.

Minimum fungicidal concentration (MFC) determination could be useful in severe fungal infections in immunocompromised patients. No reference tests to determine the MFC are available, and both macro- and microdilution methods are commonly used. In this study, discrepancies between minimum inhibitory concentrations (MICs) and MFCs of amphotericin B against 58 isolates of filamentous fungi other than Aspergillus (46 Fusarium spp., six Paecilomyces spp. and six Scopulariopsis spp.), obtained with macro- and microdilution methods, were evaluated. Additionally, the agreement between MFCs obtained by both methods were analyzed. In general MFCs were higher than the corresponding MICs overall using the macrodilution method. MFCs were more than one dilution higher than MICs in 52.3% of the cases in the macrodilution test and in 20.5% of the cases in microdilution test. The degree of agreement between MFCs obtained with the two methods was of 70.4% (Kappa coefficient of 0.5). In general, the macrodilution method showed higher MFC values than the microdilution method. Differences of up to six drug dilutions were observed between MFCs obtained by both methods.

Amphotericin B↗

Emerging pathogens.

The ever increasing numbers of immunosuppressed individuals has led to a significant increase in the incidence of opportunistic infections, particularly those caused by fungi. The epidemiology of infections caused by the common fungal pathogens such as Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus has been well documented. However, in addition to these, a number of species which have previously been unrecognized (e.g., C. dubliniensis) or have previously been assumed to be non-pathogenic (e.g., Saccharomyces cerevisiae, Scedosporium spp. and Fusarium spp.) have emerged as agents of human disease. Since these species have only been identified recently as human pathogens, their role in disease is poorly understood. In most cases, identification of these species is problematic and therefore their epidemiology has yet to be elucidated adequately. In addition, several of these species fail to respond to conventional antifungal therapies. In this article, we describe the emergence of two separate yeast species (C. dubliniensis and S. cerevisiae) and two separate groups of moulds (Scedosporium prolificans and Fusarium spp.), as human pathogens. It is apparent from what we already know, that much work has yet to be performed before we have a clear understanding of how these species cause disease and most importantly how they can be controlled.

Candida↗