Dataset Information

Characterisation of a clinical isolated Aspergillus lentulus strain using a Galleria mellonella infection model.

ABSTRACT:

Background

In recent years, the number of invasive aspergillus infection cases caused by Aspergillus lentulus (A. lentulus) has gradually increased and this fungus is usually difficult to distinguish from Aspergillus fumigatus in morphology. All of these presents a great challenge to the treatment of invasive fungal infections caused by A. lentulus. The present study aims to discuss the antifungal resistance, virulence and inflammatory factors' changes after the infection of larvae of A. lentulus separated from patients with chronic obstructive pulmonary disease (COPD) to reflect the host immune response.

Methods

A. lentulus isolated from COPD patients was identified by morphology and molecular biology, and its drug sensitivity was determined in vitro. Then the virulence factors and inflammatory response related factors of A. lentulus were determined by the model of A. lentulus infecting larvae. These were divided into three groups: A. lentulus standard strain, A. lentulus strain isolated from patients; PBS control. The infection model was formed by injecting the suspension of A. lentulus at a concentration of 1×10⁶ CFU into larvae, in order to determine the (1,3)-?-D-glucan and galactomannan levels, and determine the caspase-1 and TNF-? concentration in Galleria mellonella larvae by RT-PCR.

Results

The results revealed that A. lentulus had good sensitivity to itraconazole, voriconazole and micafungin, while (1,3)-?-D-glucan was negative in the two groups. The level of galactomannan in the two groups was higher than that in the control group, and the difference was statistically significant (P<0.05). However, there was no statistical difference between the standard strain group and patient strain group (P>0.05). After the infection of larvae, caspase-1 and TNF-? in the Galleria mellonella larvae increased in the two groups, and these elevated levels were statistically significant in both groups (P<0.05). However, there was no significant difference between the two groups (P>0.05).

Conclusions

There is no significant difference in virulence factor and host inflammatory response between A. lentulus isolated from COPD patients and standard strains. Galactomannan has more advantages in the early detection of A. lentulus invasive infection. Furthermore, the caspase-1-mediated inflammasome pathway may be involved in the host immune response to A. lentulus.

SUBMITTER: Zhang LJ

PROVIDER: S-EPMC7947491 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The Caulobacter genus, including the widely-studied model organism Caulobacter crescentus, has been thought to be non-pathogenic and thus proposed as a bioengineering vector for various environmental remediation and medical purposes. However, Caulobacter species have been implicated as the causative agents of several hospital-acquired infections, raising the question of whether these clinical isolates represent an emerging pathogenic species or whether Caulobacters on whole possess previously-unappreciated virulence capability. Given the proposed environmental and medical applications for C. crescentus, understanding the potential pathogenicity of this bacterium is crucial. Consequently, we sequenced a clinical Caulobacter isolate to determine if it has acquired novel virulence determinants. We found that the clinical isolate represents a new species, Caulobacter mirare that, unlike C. crescentus, grows well in standard clinical culture conditions. C. mirare phylogenetically resembles both C. crescentus and the related C. segnis, which was also thought to be non-pathogenic. The similarity to other Caulobacters and lack of obvious pathogenesis markers suggested that C. mirare is not unique amongst Caulobacters and that consequently other Caulobacters may also have the potential to be virulent. We tested this hypothesis by characterizing the ability of Caulobacters to infect the model animal host Galleria mellonella. In this context, two different lab strains of C. crescentus proved to be as pathogenic as C. mirare, while lab strains of E. coli were non-pathogenic. Further characterization showed that Caulobacter pathogenesis in the Galleria model is mediated by lipopolysaccharide (LPS), and that differences in LPS chemical composition across species could explain their differential toxicity. Taken together, our findings suggest that many Caulobacter species can be virulent in specific contexts and highlight the importance of broadening our methods for identifying and characterizing potential pathogens.