Citrobacter Species, Lab Report Example

The objective of this laboratory report is to distinguish and classify two nutrient broths which are composed of two distinct specimens. There is a 92.1% probability that the sample in which is identified as unknown # 2 is enterobacteriacloacae. There is a 3.1% probability that the second sample which is unknown # 11 is enterobacter amigenus 2. It is necessary to review the two organisms by applying an inoculation of the blood agar plate, MacConkey plate, CAN plate and the chocolate plate by the application of the streak plate method. The first streak plate process was conducted and positioned in the incubation device at a temperature of 37 ° C for an interval of 24- 48 hours.

After the review of the development of the growth contained in the plates, it is known that the samples pertain to the enterobacteria group of organisms. The results from the testswill be conducted in order to confirm their identities.

Procedures

Unknown # 2                                                  

Gram staining. The samples of the organisms contained in the plates must be classified as being gram positive or gram negative. This is performed by the application of a gram staining procedure (Cappuccino & Sherman 73).

In applying the purified and fresh cultures which were grown in the nutrient rich broth, a sample is positioned on the slide and permitted to desiccate prior to the application of heat. The procedure which is applied in the staining process is conducted initially by applying a crystal violet solution during the rinsing process. Subsequently, Gram’s Iodine is applied as a mordant. The sample is initially rinsed with alcohol and water. Secondly, the samples are stained with Safaranin and placed into a water rinsing solution. The next phase (Cappuccino & Sherman 73).. In applying this procedure, the outcome was deemed to be conclusive for the unknown # 2.  The unknown # 2 is composed of gram positive rods. The specimen in unknown # 11 has the appearance of being gram negative. Additional examinations are required.

The sample labeled unknown # 2 was assessed as gram positive by the blood agar plate. The sample was assessed to have a hemolytic characteristic, in addition to manifesting a grey color. The colonies were wet colonies which demonstrated lactose fermentation. The colonies in unknown # 2 were alpha hemolytic and assessed as being positive in the Strep examination. The biochemical tests for catalase and coagulate were performed and the results of both tests are positive.  In the MacConkey plate, the colonies in the unknown sample # 2 demonstrated no growth and no hemolytic qualities.

CAN Plate for Unknown # 2.The CAN plate for unknown # 2 demonstrated small colonies which demonstrated a light pink color. The colonies were shiny in their appearance with a quality of being wet.

Chocolate Plate for Unknown # 2.The colonies in the chocolate plate appeared to be small and no hemolytic had taken place. The samples demonstrated a milky color.

Unknown # 11

The samples which were contained in the blood agar demonstrated the characteristic of being gram negative. The colonies were small and gray in the characteristic.

Mac Conkey plate.The sample which was cultivated in the Unknown # 11 sample demonstrated small colonies which were lactose fermented. There was no isolation.

CAN plate. The samples which were cultivated in the Unknown # 11 demonstrated no growth and were gram negative.

Chocolate plate.The colonies demonstrated no hemolytic nature and the colonies were observed to be small.

Biochemical Test.A biochemical examination was performed. The indole examination resulted negative. An API20E  test was conducted. The characteristics which had been revealed in the biochemical tests demonstrated that the ONPG was positive and the ADH was assessed to be positive the LDC was evaluated as negative. The ODC test resulted in a positiveassessment; the CTI resulted in a negative. The H₂S test was negative, The URE exam was negative and the TDA exam was assessed as negative. The IND exam was reviewed as negative and the VP test was evaluated as negative. The GEL and the INO exams were negative. The GLU, MAM, INO, SOR RHA, SAC, MEL, AMY and ARA exams resulted positive.

Discussion

The colonies which had been identified on the unknown # 2 have the characteristic of producing catalase and are wet colonies. In addition, the unknown sample # 2 has been assessed as being coagulate positive. The colonies are alpha hemolytic .In examining the characteristics of unknown # 2, there is a high probability that the sample colonies are identified as Staphylococcus. The colonies have the potential of being Staphylococcus aureus. This is a primary pathogen for human beings that may cause food poisoning, toxic shock syndrome, scalded dermal syndrome, the formation of abscesses and suppuration. In the event that the sample is Staphylococcusepidermidis, an infection may be caused from prosthetic devices. There is also a potential of the sample in the unknown # 2 being Staphylococcus saprophtyticus. This pathogen is the major causal attribute of urinary infections in youthful females (NCKU 1).

Staphylococcus is a category of the bacteria of the Cocci category. These bacteria are encountered in human skin tissue, in the mucous cells and in the skin tissues and mucous cells of mammals and birds. The virulence factors which must be considered with Staphylococcus are that they are found in the biological acids.  These bacteria may be readily identified by their presence of catalase, the presence of coagulate and the lactose fermentation which has been manifest (NCKU 1).

The colonies had been identified as being in the enterobacteriaceae category in the unknown # 11 sample due to the gram negative rod quality. There had been slight growth on the MacConkey plate. The characteristic of being lactose fermenting causes the identification of the unknown # 11 to be the Citrobacter freundii, Enterobacter species,Klebsiella species or Escherichia coli. The indole negative and the quality of being VP negative cause the unknown number 11 to be categorized as Citrobacter freundii. The characteristic of the unknown sample number 11 having ONPG positive, LDC negative and indole negative, the sample is identified as Citrobacter freundii (UNMC 1).

The citrobacter category of bacteria is commonly encountered in food, water and soil. The citrobacter species also inhabit the gastrointestinal system of human beings and animals. In the patients who have acquired a citrobacterinfection, the bacteria are communicated from the parent to the child in a vertical manner or can be communicated from supplementary hospital sources. The citrobacterspecies may cause outbreaks which are nosocomial or sporadic.

Newborns are at an elevated risk of being infested by the citrobacter species. The citrobacter species may cause cerebral abscesses, meningitis and sepsis. Patients who have immunological deficiencies are also at risk for contracting the citrobacter infection. The citrobacter species can cause infections in the bloodstream, endocardium, meninges, peritoneum, bone, respiratory system and the urinary tract.  Citrobacter freundii is a commonly found infection.  It is resistant to chemical antimicrobial interventions (Chang 1).

Works Cited

Chang, Shan- Chwen. “Citrobacter species.”  Antimicrobial Therapy: The Ultimate Reference,2011.Web. 9 September 2014. http://www.antimicrobe.org/b93.asp

Cappucino, James and Natalie Sherman. Microbiology: A laboratory manual. San Francisco, CA: Pearson Benjamin Cummings, 2013. Print.

NCKU. “Pyogenic cocci.”National Cheng Kung University, n.d. Web. 9 September 2014. http://www.ncku.edu.tw/~microbro/course/teacher/hor/int90.htm

UNMC. “Enteric key biochemical reaction review: Biochemical reactions when motility is not available.” University of Nebraska Medical Center, 2011. Web 9 September 2014 http://webmedia.unmc.edu/alliedhealth/CLS/CLS418%2011%Rotation%20document%20Enteric%20review.pdf