Antifungal susceptibility and virulence of Aspergillus fumigatus environmental strains from a public tertiary hospital in Metro Manila, Philippines

@#<p><strong>Background and Objectives:</strong> The increase in the number of invasive Aspergillus infections has been observed among immunocompromised and hospitalized patients. In the Philippines to date, no published data focused on the prevalence of Aspergillus species or any other thermotolerant fungal species in a hospital environment. This research served as a primary study to characterize the antifungal susceptibility of environmental strains of Aspergillus fumigatus from a hospital facility against three antifungal agents and to determine the virulence of these isolates on BALB/c mice using an animal survival assay.<br /><strong>Methodology:</strong> Ten environmental strains of A. fumigatus were isolated from three air-conditioned wards in a medical facility using Andersen Air Sampler. The antifungal susceptibility profile of the isolates was determined against Voriconazole, Amphotericin B and Caspofungin. The virulence of these isolates was also tested on BALB/c mice using an animal survival assay. Moreover, the lung tissues of infected BALB/c mice were subjected to histopathological analyses using Gomori Methenamine Silver stain (GMS) and Hematoxylin & Eosin (H&E) stains.<br /><strong>Results:</strong> Etest result for antifungal susceptibility testing showed that two of the ten isolates were resistant to Amphotericin B (AF2-A and AF-3A); one isolate resistant to Voriconazole (AF2-A) and an isolate that manifested non- susceptibility to Caspofungin m(AF2-A). Epidemiological cut-off values were determined for each antifungal following the M38-A2 CLSI guidelines. BALB/c mice median survival analysis revealed that the isolate with the highest Minimum Inhibitory Concentration (MIC= 4.89 ?g/ml) for Voriconazole resulted in the most number of mortality with the least number of observation days. GMS AND H&E histopathology slides showed fungal elements embedded on left lung lobe of mice.<br /><strong>Conclusion:</strong> This study showed that there were strains of Aspergillus fumigatus from a hospital indoor air which were considered as resistant strains to Voriconazole, Amphotericin B, and Caspofungin (AF2-A and AF3-A). Lung tissues of infected mice showed characteristics of bronchopneumonia.</p>

An investigation of virulence factors of Legionella pneumophila environmental isolates

ABSTRACT Nine Legionella pneumophila strains isolated from cooling towers and a standard strain (L. pneumophila serogroup 1, ATCC 33152, Philadelphia 1) were analyzed and compared in terms of motility, flagella structure, ability to form biofilms, enzymatic activities (hemolysin, nucleases, protease, phospholipase A, phospholipase C, acid phosphatase, alkaline phosphatase and lipase), hemagglutination capabilities, and pathogenicity in various host cells (Acanthamoeba castellanii ATCC 30234, mouse peritoneal macrophages and human peripheral monocytes). All the isolates of bacteria appeared to be motile and polar-flagellated and possessed the type-IV fimbria. Upon the evaluation of virulence factors, isolate 4 was found to be the most pathogenic strain, while 6 out of the 9 isolates (the isolates 1, 2, 3, 4, 5, and 7) were more virulent than the ATCC 33152 strain. The different bacterial strains exhibited differences in properties such as adhesion, penetration and reproduction in the hosts, and preferred host type. To our knowledge, this is the first study to compare the virulence of environmental L. pneumophila strains isolated in Turkey, and it provides important information relevant for understanding the epidemiology of L. pneumophila.

Cysticidal Effect of Chlorine Against Environmental and Clinical Isolates of Acanthamoeba / Jurnal Sains Kesihatan Malaysia

Acanthamoeba is a free-living amoeba that has been identified to cause Acanthamoeba keratitis and granulomatous amoebic encephalitis. Their physiological characteristics can be related to pathogenic potential which have a medical importance. This study was carried out to investigate the value of minimum cysticidal concentration of chlorine against them. Acanthamoeba strains tested were from clinical isolates from hospitals (HSB 1, HKL 48 and HKL 95) and environmental isolates (PHS 2, PHS 11 and PHS 15). The minimum cysticidal concentration of chlorine was determined by dilution process using 12 wells microtitre plate starting with 2500 ppm. 100 μl cyst suspensions standardized at 105/ml were pipetted into all wells and incubated overnight at 30°C. Cysts were then washed using Page saline and cultured on non nutrient agar overlaid with Escherichia coli. The presence of trophozoites was then observed. The lowest concentration able to prevent trophozoites formation was noted as the minimum cysticidal concentration. Minimum cysticidal concentration test showed the same concentration of 156 ppm (156 μg/ml) chlorine solution was needed to kill all cysts of Acanthamoeba isolates. This indicates that the physiological traits of environmental and clinical isolates are the same. Isolates from the environmental specimens are also able to show the pathogenic potential similar to clinical specimens, thus capable of causing disease to human.

Presence of blaTEM-116 gene in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei from Brazil

It is known that Aeromonas spp. possess different chromosomal â-lactamase genes. Presence and phenotypic expression of blaTEM, blaSHV, and blaCTX-M ESBL-encoding genes were investigated in environmental water isolates of Aeromonas hydrophila and Aeromonas jandaei. Presence of blaSHV and blaCTX-M genes was not observed, and blaTEM gene was verified in 91 percent of the isolates. Sequencing of 10 fragments showed the occurrence of blaTEM-116.

Temperature Tolerance of Clinical and Environmental isolates of Acanthamoeba spp / Jurnal Sains Kesihatan Malaysia

Acanthamoeba is a free living protozoa that can cause keratitis and granulomatous amoebic encephalitis. Physiological characteristics of this amoeba are found to have a medical importance and related to the pathogenic potential of the organism. This study was carried out to investigate the physiological characteristic from the aspect of temperature tolerance. Six Acanthamoeba strains from three clinical isolates (HSB 1, HKL 48 and HKL 95) and three environmental isolates (PHS 2, PHS 11 and PHS 15) were used in this study. Test was done by culturing cysts at 30°C, 37°C and 42oC for two weeks and the ability of cysts to change to trophozoites were observed. The result showed all strain was able to change to trophozoites at 30°C and 37oC. However, no trophozoites were observed at 42oC. This indicate that there is a similarity in the physiological trait of strains from both isolates are the same and strains from the environment are able to show the pathogenic potential thus capable of causing infection to human.