Bacterial growth


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Bacterial growth

The processes of both the increase in number and the increase in mass of bacteria. Growth has three distinct aspects: biomass production, cell production, and cell survival. Biomass production depends on the physical aspects of the environment (water content, pH, temperature), the availability of resources (carbon and energy, nitrogen, sulfur, phosphorus, minor elements), and the enzymatic machinery for catabolism (energy trapping), anabolism (biosynthesis of amino acid, purines, pyrimidines, and so forth), and macromolecular synthesis [proteins, ribonucleic acid (RNA), and deoxyribonucleic acid (DNA)]. Cell production is contingent on biomass production and involves, in addition, the triggering of chromosome replication and subsequent cell division. The cells may or may not separate from each other, and the division may partition the cell evenly or unevenly. Alternatively, growth may occur by budding (unequal division). Most cells so produced are themselves capable of growing and dividing; consequently, viability is usually very high when growth conditions are favorable. Moreover, in many cases the incidence of death is surprisingly low in the absence of needed nutrients. Many bacteria differentiate into resistant resting forms (such as spores); others may simply reduce their rate of metabolism and persist in the vegetative state for long times.

References in periodicals archive ?
Potable water systems, cooling towers, whirlpool spas and decorative fountains offer common environments for bacterial growth and transmission if they are not cleaned and maintained properly.
The reason these materials are relatively unaffected by bacterial growth is due to their thicker dimension and insulative properties.
Of the 49 samples which were positive for bacterial growth, 36.7% grew coliform bacteria, a group which includes E.
Out of the 49 samples which were positive for bacterial growth, 36.7 percent grew coliforms, 36.7 percent Enterococcus spp, and 14.3 percent S.
Bacterial growth was calculated as the increase in cellular density from the beginning to the end of the exponential growth period.
aureus) to each concentration of nanopracticle and the results showed that the influence of the AuNPs on different bacterial growth. The presence of AuNPs slightly inhibited bacterial growth (Figure 1).
Anaerobic culturing requires zero percent oxygen during the entire incubation period, to guarantee a great bacterial growth yield.
Hygienic and ideal for food and pharmaceutical applications, the pallet's material resists extreme temperatures, bacterial growth, corrosion and UV light.
The short time points (<20 min) were used as a strategy to control for any PM-induced bacterial growth (Borcherding et al.
In bacterial respiratory tract infections, the patient's main complaints are high-grade fever, purulent nasal discharge, cough which produces phlegm and the investigations show increase in total leucocyte count (> 11000 cells/cumm), increased polymorphs (> 60%) in differential leucocyte count, swabs taken from nasal secretions and throat are positive for bacterial growth and chest x-ray shows infiltrations or consolidation or pleural effusion.
The effect of phage (SA, SANF and SA2) antibacterial activity on the bacterial growth was tested in commercial pasteurized milk at 25degC and 37degC, at multiplicity of infection (MOI; the ratio of phage concentration/bacterial concentration) of 100.
coli O157 (NCTC) 12900 (Laboratory Razi Vaccine and Serum Research Institute, Karaj, Iran) was grown up in nutrient broth culture (NB) for 24 h at 37degC to determine pH, NaCl, ORS and temperature stress factors on bacterial growth. The bacteria were experimented in different conditions including; pH (4 to10), NaCl (0.5 to 5 g), ORS (1 to 8 g) and temperature (4 to 55degC) in Ben Murray, Incubator, Electrode pH meter and Refrigerator (Dewanti and Wong, 1995; Gabriel and Nakano, 2010a).