Latest News on Environmental Microbiology: March 2021

Oligonucleotide microchips as genosensors for determinative and environmental studies in microbiology.

The utility of parallel hybridization of environmental nucleic acids to many oligonucleotides immobilized in a matrix of polyacrylamide gel pads on a glass slide (oligonucleotide microchip) was evaluated. Oligonucleotides complementary to small-subunit rRNA sequences of selected microbial groups, encompassing key genera of nitrifying bacteria, were shown to selectively retain labeled target nucleic acid derived from either DNA or RNA forms of the target sequences. The utility of varying the probe concentration to normalize hybridization signals and the use of multicolor detection for simultaneous quantitation of multiple probe-target populations were demonstrated. [1]

Nosocomial aspergillosis: Environmental microbiology, hospital epidemiology, diagnosis and treatment

Epidemiology, diagnosis and treatment of nosocomial aspergillosis. Appropriate environmental control measures are important in preventing or arresting an outbreak of nosocomial aspergillosis. These include selective environmental microbiological surveillance and floor to ceiling barriers during construction or renovation. These is particularly important for the bone marrow transplant units and units with persistently granulocytopenic patients. We have summarized the point source and cited or formulated the environmental correction measures relating to 25 outbreaks of nosocomial aspergillosis involving a total of more than 100 patients. The most frequent settings of nosocomial invasive aspergillosis occurred in granulocytopenic patients following respiratory infection from an airborne source, associated with hospital construction or contaminated ventilation systems. [2]

Life, Death, and In-Between: Meanings and Methods in Microbiology

Determination of microbial viability by the plate count method is routine in microbiology laboratories worldwide. However, limitations of the technique, particularly with respect to environmental microorganisms, are widely recognized. Many alternatives based upon viability staining have been proposed, and these are often combined with techniques such as image analysis and flow cytometry. The plethora of choices, however, adds to confusion when selecting a method. Commercial staining kits aim to simplify the performance of microbial viability determination but often still need adaptation to the specific organism of interest and/or the instruments available to the researcher. This review explores the meaning of microbial viability and offers guidance in the selection and interpretation of viability testing methods. [3]

Microbiological Analysis of Ready-To-Eat-Foods Obtained from Bukaterian within the Ekiti State University and Environment, Ado-Ekiti, Nigeria

Food-borne diseases are the global public health problem. At random 75 food samples comprising of fifteen each of the five commonly eaten ready-to-eat foods (rice, beans, yam, fufu and meat) were collected from different vendors of the university. Aerobic bacterial count and fungal count were determined by counting the colonies on nutrient agar plates and saboraud dextrose agar plates respectively. The identification of the organisms was determined by their morphology, culture characteristics and biochemical profile. The result obtained revealed that Mean aerobic plate counts ranged from 1.0 x 10² cfu/g (rice) to 6.0 x 10⁴ cfu/g (meat) and mean fungal count ranged from 1.3 x 10² cfu/g (rice) to 5.2 x 10⁴ cfu/g (meat). A total of eleven species (spp) of microorganisms including Escherichia coli, Bacillus cereus, Salmonella spp., Clostridium perfringens, Shigella spp., Klebsiella spp., Proteus spp., Staphylococcus aureus, Campylobacter spp., Aspergillus spp. and Mucor spp. were isolated from the food samples. Bacillus cereus had the highest percentage frequency with (18.12%) while Campylobacter spp. had the lowest percentage frequency with (1.45%). Fufu had the highest percentage of contamination of 35.51% with lowest in yam and meat which both had 5.8%. Based on the specifications by International Commission for Microbiological Specification for Foods (ICMSF), the level of contaminations was within acceptable microbiological limits except for Meat and Fufu; this could be attributed to inadequate processing, poor handling practices and post-cross contamination which can pose danger to the health of the consumers. It is recommended that regular microbiological quality control programs and good hygiene practices should be encourage. [4]

Microbiological Impact Assessment of Air Environment of the Hides and Skin Processing Unit of NILEST Tannery, Zaria

Introduction: Microbial analysis of air is one of the most vital investigations of determining the microbial air pollution. The information on the microbial concentration of bacteria and fungi is necessary both to estimate the health hazard and to create standard for air quality control.

Aim: This study was carried out to investigate the microbiological quality of the air environment in the hides and skin processing unit of NILEST Tannery, Zaria.

Methodology: The analysis was carried out using the settle-plate method. The plates were exposed during passive and active sessions for 30 to 60 minutes.

Results: The bacteria isolated and identified include Proteus mirablis, Pseudomonas aeruginosa, Salmonella enterica, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniawhereas the fungi isolated include Sclerotium sp., Fusarium sp., Aspergillus niger, Aspergillus fumigatus, Corticium sp., and Aspergillus ficheri. The mean total bacteria load recorded during passive and active sessions were 180 cfu/m³ and 254 cfu/m³ respectively. Those of fungi were 115 cfu/m³ and 284 cfu/m³respectively.

Conclusions: The isolation of these microorganisms from the study area is indicative of workers being exposed to potential bio-hazards and therefore there is the need for adequate measures to reduce the risk of exposure to pathogenic strains. [5]

Reference

[1] Guschin, D.Y., Mobarry, B.K., Proudnikov, D., Stahl, D.A., Rittmann, B.E. and Mirzabekov, A.D., 1997. Oligonucleotide microchips as genosensors for determinative and environmental studies in microbiology. Applied and environmental microbiology, 63(6), pp.2397-2402.

[2] Walsh, T.J. and Dixon, D.M., 1989. Nosocomial aspergillosis: environmental microbiology, hospital epidemiology, diagnosis and treatment. European journal of epidemiology, 5(2), pp.131-142.

[3] Davey, H.M., 2011. Life, death, and in-between: meanings and methods in microbiology. Applied and environmental microbiology, 77(16), pp.5571-5576.

[4] Akindele, P.O. and Ibrahim, K.A., 2016. Microbiological Analysis of Ready-To-Eat-Foods Obtained from Bukaterian within the Ekiti State University and Environment, Ado-Ekiti, Nigeria. Journal of Advances in Microbiology, pp.1-8.

[5] Oko, J.O. and Abua, R., 2016. Microbiological Impact Assessment of Air Environment of the Hides and Skin Processing Unit of NILEST Tannery, Zaria. Archives of Current Research International, pp.1-6.