ABSTRACT
In recent years, coagulase negative Staphylococci(CONS) are increasingly recognized as one of the major causes of health care associated infections (HCAI). CONS infections are one of the major causes of morbidity and mortality in hospitalized patients. As CONS colonize various parts of the skin and mucous membranes, most of infections are en-dogenous in origin. However, they are also transmitted exogenously via various medical/ surgical procedures. The aim of present review article is to update and summarize the information available on medically important CONS with special reference to epidemiology, laboratory diagnosis and antibiotic resistance.
ABSTRACT
Aim: The study aimed to evaluate the effects of various concentrations of organophosphate agrochemicals, namely monocrotophos and glyphosate on soil chemical parameters, microbial population and activities of certain vital exoenzymes e.g. invertase, amylase, cellulase, dehydrogenase and protease at 7 days interval over an incubation period of 84 days. Methodology: Three concentrations of monocrotophos (1.0 g kg-1 soil-low T1, 2.0 g kg-1 soil-medium T2, 3.0 g kg-1 soil-high T3) and glyphosate (0.1 g kg-1 soil-low T1, 0.15 g kg-1 soil-medium T2, 0.2 g kg-1 soil-high T3) were applied to soil. Soil pH, electrical conductivity, organic carbon (OC), available nitrogen, phosphorous and potassium (NPK) were assessed. Bacterial and fungal population along with activities of exoenzymes were also studied. Data were analysed using two way ANOVA and Duncan's multiple range test (DMRT). Results: Significant variations (p<0.05) of chemical parameters, except P and K, in treated soil between concentrations and time over the incubation period were observed. Microbial population and exoenzymes showed significant variations (p<0.05) in response to agrochemical treatments. Invariably, lower microbial load and enzyme activities were noticed in treated soil relative to control. Interpretation: The study indicated that monocrotophos and glyphosate at recommended and elevated concentrations in soil could adversely impact microbial growth. Inhibited microbial population culminated in lower exoenzyme activity
ABSTRACT
Aims: To investigate the effect of human serum, starvation and /or variation in incubation temperature on yeast and pseudo-hyphae and/ or hyphal cell differentiation in vaginal Candida albicans strains and, its correlation to exoenzymes productivity. Study Design: A total of 31 C. albicans strains previously isolated from high vaginal swab specimens of pregnant Saudi women, as well as the C. albicans QC strain ATCC 10231 were recruited from Brain Heart Infusion-glycerol stock cultures(-80ºC) & included in the study. Place and Duration of Study: Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia, between September 2013 and December 2013. Methodology: Each of thirty one vaginal C. albicans strains and the QC strain (ATCC 10231) was grown in Modified Sabouraud Broth (MSB) at 25ºC and at 37ºC with or without addition of 20 % human serum; and morphological growth was observed at 2 hours intervals by phase contrast microscopy. Selected C. albicans strains that showed ability and/or weak-ability of yeast-hyphal transition were also tested for their exo-hydrolytic enzymes of phospholipase, and proteinase as caseinase, & gelatinase, and coagulase, virulence markers. Results: Showed that at 25ºC 28/31(90.3%) strains were non filamentous, 3/31(9.6%) strains were moderately filamentous, and 0.0% strong filamentous, in comparison, at 37ºC those numbers were 19/31(61.3%), 10/31(32.3%), and 2/31 (6.4%) respectively, suggesting that mere increase in temperature from 25ºC to 37ºC remarkably increases yeast morphogenesis to filamentous forms. Such increase was significantly (P<0.001) more pronounced upon the addition of 20% serum at either incubation temperature of 25ºC or 37ºC as expected. Generally the presence of serum and/or incubation at high temperature (37ºC), speeds off hyphal growth formation. Additionally, results also showed that 8/31 (25.8%) strains exhibited transition to hyphal forms only in presence of serum, whereas 7/31 (22.6%), apparently lost their capacity to switch to hyphal forms even in presence of serum and/or at temperature of 37ºC incubation. In contrast three strains 3/31, (9.7%) expressed such ability of filamentous growth in presence or absence of serum at 37ºC as well as 25ºC. These strains also showed enhanced secretion of exoenzymes. Therefore, these strains would be the most virulent ones. Whereas those strains (7/31, 22.6%) that did not show filamentous growth at any of the examined growth conditions would be considered as less virulent strains. However, considering the limited number of strains tested in this study, these findings require further substantiation by large sample size and in vivo animal studies. Conclusion: Results obtained suggest that vaginal C. albicans strains are heterogenous in their potency to switch from yeast to hyphae. Strains which show morphogenesis in absence of serum and/or at low temperature (25ºC) exhibit higher exoenzymes activity suggesting that these strains are more pathogenic.