Yogurt. Enumeration of characteristic microorganisms. Colony-count technique at 37 °C

Keyword(s):  
Author(s):  
Raghdaa K. Fayad ◽  
Roda F. Al-Thani ◽  
Fatima A. Al-Naemi ◽  
Mohammed H. Abu-Dieyeh

This research was conducted to investigate the dynamics of airborne fungi using viable culture collection and in respect to different abiotic variables, including seasonal and intra-diurnal variations. A gravimetric method was used to sample airborne fungal deposition on potato dextrose agar plates on alternate days, for a year between April 2015 to March 2016. From 176 settle plate exposures, a total of 1197 mould and 283 yeast colony-forming units (CFU), 21 genera and 62 species were retrieved. The highest fungal spore count was recorded in February 2016, whereas the lowest count occurred in August 2015. The main constituents of the fungal airspora were attributed to Cladosporium (60.2%), Aspergillus (10.4%), Fusarium (9.4%), Alternaria (8.5%), and Ganoderma spp. (2.3%). Temperature was negatively correlated with total colony count (r = −0.231, p ≤ 0.05) or species richness (r = −0.267, p ≤ 0.001), while wind speed was positively correlated with total colony count (r = 0.484, p ≤ 0.001) or species richness (r = 0.257, p ≤ −0.001). The highest dispersal of fungal spores was obtained at 18:00, whereas the lowest fungal spores release was recorded at 00:00 (midnight). There were no significant differences in species composition and richness of the airborne fungal population between two study sites, the Industrial area and Qatar University Campus. The count of Alternaria spp. and Fusarium spp. were significantly higher at the Industrial area site, which corresponds to a higher CO2 level than the Qatar University site. This study lays the foundation for future work to assess the implications of such aeromycological data on public health.


2014 ◽  
Vol 9 (2) ◽  
Author(s):  
Nafisa Rashid ◽  
Mir Misbahuddin ◽  
Zubaida Khatoon Choudhry ◽  
Ahmed Abu Saleh ◽  
Naseer Ibn Sattar

2021 ◽  
Vol 9 (8) ◽  
pp. 1597
Author(s):  
Dominic Stephenson ◽  
Audrey Perry ◽  
Andrew Nelson ◽  
Ali E. Robb ◽  
Matthew F. Thomas ◽  
...  

Nontuberculous mycobacteria are important respiratory pathogens in patients with cystic fibrosis (CF). For diagnosis, international guidelines recommend culture of sputum that has been decontaminated via chemical treatment. Fifty-six sputum samples from 32 patients known to be previously colonized or infected with NTM were subdivided, and the aliquots were subjected to six different decontamination strategies, followed by quantitative culture for NTM. Thirty sputum samples contained Mycobacterium abscessus complex (MABSC) and 11 contained Mycobacterium avium complex (MAC). Decontamination strategies included treatment with N-acetyl L-cysteine with 2% sodium hydroxide (NALC-NaOH), 4% NaOH, 1% chlorhexidine, 0.5 N sulfuric acid, 5% oxalic acid, double decontamination with NALC-NaOH, followed by 5% oxalic acid, and saline (0.85%) as a control. The samples were also cultured directly with no treatment. Treatment with NALC-NaOH resulted in an average reduction in colony count of 87% for MABSC when compared with direct culture. NaOH at 4% caused a 98.3% average reduction in colony count. All treatments that included NaOH resulted in colony counts that were statistically lower than those obtained from direct culture or the saline-treated control (p < 0.05). Standard treatments using sulfuric or oxalic acids were less deleterious, but still resulted in an average reduction in colony count of at least 30%. The viability of MAC was much less affected by most decontamination treatments. In conclusion, the viability of MABSC was severely compromised by standard decontamination regimens. This supports recent evidence showing that optimal recovery of MABSC is achieved by culture on an appropriate selective agar without decontamination of sputum samples.


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