S. Marcenscens Research Paper

Unlike many environmental bacteria, Pseudomonas aeruginosa has a remarkable capacity to cause disease in susceptible hosts. It has the ability to adapt to and thrive in many ecological niches, from water and soil to plant and animal tissues. The bacterium is capable of utilizing a wide range of organic compounds as food sources, thus giving it an exceptional ability to

While the bacteria S. marcescens was considered to be harmless in the past, it has been identified in recent years as a cause of serious

As the flowchart shows, a series of tests were conducted to identify the unknown bacterium #65. Microscopic observation of the gram stain indicated a gram-positive coccus bacterium. S. epidermidis was used as the gram-positive control while E. coli was used as the gram-negative control. This observation led to the elimination of all gram negative and rod-shaped genera: Enterobacter, Citrobacter, Klebsiella, Escherichia, Pseudomonas, Serratia, Alcaligenes, Neisseria, Proteus, Salmonella, Shigella, Erwinia, Veillonella, Flavobacterium, Bacillus, Arthrobacter, Lactobacillus, Listeria and Kurthia (2). By performing the catalase test, it was determined that the bacterium was catalase negative and it did not produce bubbles. M. luteus and E. faecalis were used as positive and negative controls, respectively.

Unknown lab report# 24 Introduction Microbiology is a study of organisms that surrounds us every day. It requires an educational understanding to identify organisms, and the ability to distinguish different bacteria’s. In applying the learning process of the different bacteria’s, unknown bacteria samples are given to be studied and identified.

I discovered that my unknown organism was Serratia marcescens. This organism is gram negative and bacillus shaped. It is a member of the Enertobacteriae family. This organism appears a red blood like color when it grows on media. It is anaerobic, but can also survive under aerobic conditions. There are some strains of Serratia marcescens that are motile and have flagellum. It is able to produce the enzymes chitinase, lipase, protease, nuclease, and serrawttin. It is a non-endospore forming bacteria, chromogenic, and does not ferment lactose. (Falkiner, 1997)

Identifying Features- Typically 4 to 6 feet, and 660 to 1,100 pounds. Skin is primarily black, with varying pale spots and a pinkish-white underbelly. Lacks a hard shell but instead has a carapace composed of tough, rubbery skin and thousands of tiny bone plates Its carapace is large, elongated and flexible with 7 distinct ridges running the length of the animal. Front flippers lack claws or scales and back flippers are paddle-shaped.

Historically, gram-negative bacteria contributed principally to the case frequency of sepsis, yet the frequency of gram-positive etiologies have approached the historic gram-negative trend12. Currently, both gram-negative and gram-positive bacteria comprise the major contributors to cases of sepsis12. Multiples studies have demonstrated the prevalence of gram-positive microbial sepsis in recent years12,14. Sepsis originating from a multi-microbial infection produces 4.7% of cases 12. Sepsis of a fungal etiology is responsible for 4.6% of cases, and the incidence of fungal cases have increased proportionally with the overall incidence of sepsis12. Anecdotally, concerns exist regarding the effects of climate change on selecting temperature-tolerant

The best and most accurate way of identifying an unknown microorganism is by sequencing its DNA, but this is very expensive and only used in highly qualified labs. So, the identification of unknown bacteria number 63 was be done by putting the bacteria through numerous laboratory tests. Microorganisms are different among each other by their macroscopic morphology, microscopic morphology, and the unique metabolic processes they use to survive and reproduce. Identifying an unknown microorganism in the laboratory is important because knowledge is gained on the appropriate way to cultivate an organism, how to correctly read the result of a test, and learning about the different characteristics of the bacteria. All of the following tests were done using the best sterile technique and the most new turbid bacterial growth subculture.

Introduction: A frequent matter in the science, medical and pharmaceutical world is identifying unknown bacteria. Throughout the past months of this class we have learned lab technique and how to do a variety of different tests on bacteria. Microbiology is not only an academic understanding of microorganisms but learning how to practically use lab procedures to properly identify and test organisms. There are several reasons one might need to identify a bacteria. It could be to find out the causative agent in a patients disease or to figure out the antibiotics that need to be administered.

In our world we are surrounded by microorganisms, some are harmless, many are beneficial; they are a part of our normal flora on our skin and in our intestines, providing a barrier against microorganisms that may not be so harmless. It is important, however, to distinguish which microorganisms are potentially pathogenic from those that are not, and when someone does get ill to determine what the organism is so appropriate treatment can be determined.

The results showed that foods contaminated by these pathogens “caused 9.4 million illnesses, 55,961 hospitalizations, and 1,351 deaths each year” (p. 12).

Serratia Marcescens are rod-shaped bacteria in the family Enterobacteriaceae. They are a group of Gram negative bacterium that are opportunistic human pathogens humans(Petersen and Tisa 2013). The genus Serratia has 14 recognized species with 2 subspecies(Mahlen 2011). S. marcescens cause in hospital-acquired infections (HAIs) (Sydnor and Perl 2011) and diarrhea associated with HIV/AIDS. Serratia can survive in different environments like water, soil, and the digestive tracts of various animals Petersen and Tisa 2013). In the gastrointestinal tract, it can destroy microvilli and vacuolization. It can also cause nosocomial infections like catheter-associated bacteremia, urinary tract infections respiratory tract infection, meningitis, bacteremia

Serratia Marcescens is a rod (bacillus) shaped bacteria known best for its red coloration. It has a single arrangement and is Gram negative. It grows at room temperature and can be found in soil, water, animals and on plants, but it is especially common in damp areas such as bathrooms or kitchens. Like all bacteria, it reproduces by binary fission. Serratia Marcescens mainly causes urinary and respiratory tract infections but can also cause pneumonia, bloodstream infections, wound infections, and meningitis along with a variety of other infections. It can be difficult to treat S. Marcescens as it is resistant to various antibiotics. In this experiment we tested the effects of antiseptics on the zone of inhibition on serratia marcescens.

aeruginosa has a large genome at 6.26 Mb, which codes for 5,697 genes, the bacteria measures 0.5 to 0.8 µm by 1.5 to 3.0 µm. It can often be found growing were nutrients are limited, like distilled water, it can use more than seventy-five different organic compounds. P. aeruginosa is one of the top three nosocomial infections, resulting in almost 10% of all hospital-acquired infections, with a blood poisoning mortality rate of nearly 50%. This opportunistic pathogen can cause pneumonia, urinary tract infections, and blood poisoning in wounded patients. The most serious complication of P. aeruginosa is cystic fibrosis, a respiratory tract

I used a sample from that MSA streak plate to inoculate urea, glucose, and catalase. I also checked my mannitol, galactose, and gelatin samples for my gram negative. Upon inspection, my unknown did ferment mannitol (Picture F). So I moved onto my gelatin, which was next on my dichotomous key. Gelatin was still present when I pulled it out of the refrigerator (Picture G). Looking at my Dichotomous key, this told me my gram negative sample was Serratia marcescens. Galactose was not fermented either. Using our data table about physical and metabolic characteristics of gram negative bacteria, it helped confirm that all my tests supported Serratia marcescens as the correct gram negative unknown.