Presence Of Microbial Flora Research Articles

A study on microbial flora and quality of raw and pasteurized milk from Hyderabad Telangana state, India

The present study is to investigate the presence of microbial flora and its quality in raw and pasteurized milk. The milk samples were collected from two different locations in Hyderabad region. A total number of twenty samples were studied including two popular brands of pasteurized milk from dairy out lets. The samples were examined for enumeration of microbial flora on TPC (Total Plate Count) and TCC (Total Coliform Count). The range of TPC and TCC are 1.5x108 to 1.25 x 107 CFU/ml respectively. Purity of pasteurized milk is good in nature. In the present work, preliminary investigations were carried out to ascertain the physicochemical characteristics and nutritional values of various milk samples. Ten raw milk samples and ten pasteurized milk samples from different places of Hyderabad were examined, for a period of six months and analyzed for microbial quality and microbial flora. Pasteurization ensures the quality of milk is up to their required standards.

Microbial flora on the white coats of dental health care professionals

Objective: To determine the types of microbial flora present on the white coats of dental healthcare professionals in a Dental Institution and Hospital. Materials and Methods: A total of 100 white coats of dental healthcare professionals were included in the study. An informed consent and questionnaire were taken. A cross-sectional survey was designed with bacterial contamination of white coats in three predetermined areas (chest, pocket, and sleeves). Sterile swabs were moistened with sterile saline. The growth on the plates was determined based on colony morphology, gram-staining, and standard biochemical tests. Chi-square test was used to assess the association among the study variables. Results: Of the total sample, five washed their white coats every day, 60 weekly once, and 35 weekly twice. About 12% of the doctors exchanged their white coats. About 33% of the doctors wore their white coats while eating. Staphylococcus aureus was the most predominant isolate found on the sleeves, and Escherichia coli was found on the pockets. Most of the organisms were seen Gram-positive staphylococci and Gram-negative E. coli. No statistically significant association between the overall presence of microbial flora was observed when compared with different gender, frequency of washings, and practice of exchanging. Conclusions: White coats are a potential source of cross-infection even in dental settings and surroundings. It is therefore recommended that guidelines be prepared for handling and cleaning procedures of white coats.

Persistence of low-pathogenic H5N7 and H7N1 avian influenza subtypes in filtered natural waters

Wild aquatic birds are the natural reservoir of avian influenza virus (AIV), and the virus is transmitted among birds through a fecal-oral route. Infected birds excrete significant amounts of AIV into the environment, and thereby sustain the circulation of AIV in the bird populations. Improved knowledge on the influence of environmental factors on the persistence of AIV in natural habitats would be valuable for risk assessments. The presented work investigated the persistence of two low-pathogenic AIV subtypes in natural water samples. The study included two AIVs formerly isolated from wild ducks, which were suspended in filtered natural fresh, brackish or sea water with salinity of 0, 8000 and 20,000 parts per million (ppm), respectively. Also sterilized brackish and sea waters were included in order to examine the influence of microbial flora on virus persistence. All water samples were incubated at temperatures representative for seasonal variation of ambient temperatures in Northern Europe (4, 17 and 25 °C). The results showed a clear correlation between persistence of viral infectivity and temperature, salinity and presence of microbial flora. While independent of virus subtype, the persistence of infectivity was negatively affected by increased temperature, salinity as well as presence of natural microbial flora. The study provides insight on impact of essential physical, chemical and biological parameters on persistence of AIV in aquatic environments. Studies determining the importance of additional environmental parameters and the detailed mechanisms of microbial inactivation of AIV should be encouraged.

Electron microscopic and chemical study of degraded Pinus radiata wood from a marine pile

During an inspection of marine piles, 12 years after installation, severe degradation was noted on one of them in the vicinity of a corroded eyebolt. The wood was dark brown in colour and tended to crumble easily. Wood fragments were examined by light microscopy and scanning and transmission electron microscopy and were also analyzed for carbohydrates and lignin. Light microscopy indicated numerous cracks in tracheid walls resulting in delamination at the middle lamella – S1 and S1–S2 boundaries and also in fractures across the tracheid wall. Chemical analysis showed extensive loss of both hemicellulose and cellulose. Observations with polarized light microscopy supported the data from chemical analysis on cellulose degradation, indicating a loss of crystallinity. Although presence of microbial flora in the lumen of wood cells was revealed by scanning electron microscopy, transmission electron microscopy showed only occasional soft rot decay zones in the S2 layer. The degradation of Pinus radiata wood from this sample appears to have been caused primarily by brown rot attack and (or) iron corrosion products, soft rot attack playing a minor role. Key words: Pinus radiata wood, marine pile, wood cell wall degradation, electron microscopy.

Action de la flore microbienne du tractus digestif sur le metabolisme des acides biliaires chez le rat

An isotopic balance is established in rats receiving a regular feed intake of [4- 14C] cholesterol so that various chemical species of bile acids have the same specific activity. This property is used to study bile acids distribution in the rat liver, digestive tract and fecal excretion. Bile acids are separated by thin-layer chromatography, radioactivity is determined by liquid scintillation, and the mass by 3-hydroxysteroid dehydrogenase action. The resulting comparative study made between the germ-free rat (axenic rat) and the rat exposed to microbes (“holoxenic” or conventional rat) receiving a semi-synthetetic feed, shows the influence excercised on the metabolism by the microbial flora of the digestive tract. This study confirms that the axenic rat compared to its holoxenic homologue has a higher bile acids pool and a lower fecal excretion. At all levels of the digestive tract (small intestine and the whole caecum and large intestine), probably as well as in the liver, the total amount of bile acids which is observed in the axenic rat is about twice the amount observed in the holoxenic rat, but fecal excretion is decreased by 20%. Values obtained by this method are higher than those previously observed by other authors using gas-liquid chromatography or [ 14C]cholic acid isotopic dilution. This study also confirms that cholic and β-muricholic acids are the main bile acids in the axenic rat and in addition establishes that in this animal bile acids composition is complex and varies from the small intestine to the feces. Besides cholic, α- and β-muricholic, chenodeoxycholic and ursodeoxycholic acids, unidentified chemical species constitute 21% of the whole in the feces. Comparing the compositions observed in axenic and holoxenic rats in this experiment, it could not be determined if the relative activity of the two pathways of bile acid biosynthesis is deeply or only slightly changed by the presence of microbial flora. This is because of a large fraction of unknown composants in the feces of the axenic rat and the extreme complexity in the feces of the holoxenic rat.