Principle of Disease Investigation in Medical Microbiology

This report discusses the principles of disease investigation in medical microbiology and its application in identifying urinary tract infections. It covers the plating technique and API test strip for microbial analysis. The case study of Mr. John Smith is used as an example.

Principle of disease
investigation in medical
microbiology

Contents
INTRODUCTION...........................................................................................................................3
MAIN BODY ..................................................................................................................................3
Material and method....................................................................................................................3
Result............................................................................................................................................5
DISCUSSION AND CONCLUSION.............................................................................................7
REFRENCES............................................................................................................................................9

INTRODUCTION
Microbiology is the biggest field of scientific study which is use for the study of
microbes and the features. Farther it divided into the small sub branches such as bacteriology,
virology, immunology, medial microbiology, all these field deal with study of types of microbes,
their characteristics, their impact on human immune system and health (Barer, and Irving,
2018). Purpose of this report is to use the medical microbiological interpretation for identifying
the problem of case study of Mr. John Smith, related to the urine tract infection, by the
application of microbial test such as the plating technique and API test strip. These techniques
are going to be apply in order to analyze the infection causing microbe.
MAIN BODY
Medical microbiology it is the biggest sub unit of microbiology which deals with the
study of impact of every single type of microbes, in human body system along with the
development of medical tenement’s, medicines for every type of microbial decease. Function of
medical microbiology is to develop the prevention strategies, diagnosis techniques, the majority
of Microbes which causes the infectious disease are fungi, bacteria, parasites and viruses.
UTI (Urinary tract infections) this is the type of physical health issues which develop due
to the microbial infection in any part of the urinary system, such as in the bladder or urethra, that
most commonly occur in the bladder or urethra. This infection possess the various symptoms like
pelvic pain, increased urination, blood in the urine, fever, vomiting.
Material and method
For the identification of UTI causing microbe, two methods was used plating technique
and API test strip. material required for the plating technique are (CLED) cysteine lactose
electrolyte deficient agar along with 10μl calibrated disposable inoculation loop (Leber, A.L.,
2020).
PLATING INOCULATION
In context to the analysis of UTI, plating technique is going to be use . For plating
inoculation, it required labeled (CLED) plate with the name of group and date as well as patient

name, then for initiating the procedure it requires gently mix of the collected patient urine sample
by avoiding the foaming. then inoculated the plate by dipping a sterile inoculation loop into the
sample, after the collecting the sample in loop it followed by gentle streaking of the sample at the
surface of agar plate (Woodford, 2018).
INCUBATION
After the inoculation it followed with the incubation of inoculated plate at 37C for 18
hours it can be incubate for overnight. after the 18 hours’ incubation it proceed with the colonies
counting by the use of colonies counter along with the identification of medium color around the
colonies (Jiang, Liu, Ma, and Lv, 2018).
GRAM STAINING
For the identification of bacterial class, it proceeds with the gram staining method, for
this method it needs the preparation of air dried smear by the use of sterile loop, 10μl water,
clean glass slide. then placed one of the colonies at test tube for dilution over the 10μl water
then placed the drop of dilution on the clean slide. after the smear preparation it needs the heat
fixing and it did by passing the smear slide through Bunsen flame 5 times then (Oba, and et. al.,
2020). Farther it proceeds with the crystal violet staining then it rinses with the water (Murray,
2017). Then it followed by the gram’s iodine addition for 1 mint, after the addition of iodine it
rinses with the alcohol, acetone for decolonization. axes ethanol is riced with water then it
observed under the microscope at 100 x with the oil immersion. then result is noted down in the
table 3.
API 20 STRIP DILUSION TEST
In order to analyses and confirm the urinary tract infection this SPI 20 strip dilution test
was accomplished which identified the microorganism as gram negative bacteria. So we farther
proceed with the API 20 strip for the identification of inoculated organisms’ enzymatic activity
so that it aids to identify the bacteria. its begged with the labeling of try, to make the humid
incubation try by dispensing approx. 5ml of distilled water to it. then API gallery is removed
from sealed envelope and then placed in to the incubation try. sterile loop is used to pick an
isolated colony from the CLED plate then it transfers to the Bijou (API 20E) and emulsified the
inoculum by rubbing it against the side of the tube (Raddaoui and et. al., 2018). then suspension
is visibly turbid. farther it proceeds with the inoculation of the API galleries, gallery contains

micro tubules each of which is consist of a tube and cupule section (Birnie, Hay, 2017). by using
the sterile Pasteur pipette, inoculate is added into tube section of micro tubules by placing the tip
of pipette on the against the side of tube (Al Zuhairi, 2020). avoided the air bubble’s, where the
box is having three quarter then filled the whole tube to the top and where the micro-tubules
don’t have the three quarter line, then there half of the tube is filled. where the micro-tubules are
underlined, its filled half with the inoculum and then remaining space is filled with the molten
petroleum jelly. finally, the plastic lid is placed to the try and incubated the galleries at 35-37.C
for 18 hours (Vik, Bollestad, 2018). After the incubation the micro-tubules color along with the
interpretation tables is used to understand the result and organisms detailed (Shimizu and et. al.,
2020). If all conducted test result as the presence of E. coli along with the of bacillus then this
will be consider as the Urinary tract infection.
Result
Table 3 result of the sample inoculation.
Patient name Mr. John Smith
Date 13/10/2020
Number of the organisms 29*4=116
Number of the organisms’
cfu
Number of the organisms
cfu
Urinary tract infection confirmed? Yes
Gram reaction Negative
Cellular morphology/shape Bacilli, long rod shape
Color colonies Yellow red
Color of agar Yellow red

Interpretive data for Organism 2: Yellow red
Gram Stain for Organism 2: Gram negative

Organism 2 – API 20E strip
Name of the organism is E. coli
DISCUSSION AND CONCLUSION
From the above research it has been concluded that the medical biology is the filed which
deals with the study of microbial disease and for the development of diagnosis, treatment along
with selection and production of particular medicine related to the microbial infection. the result
of inoculation plating and API test strip research interpreted that Mr. smith is UTI positive and
the causative agent is E. coli along with the presence of bacillus. identification of causative agent
aid to prescribe the right medical intervention along with the precautions.

REFRENCES
Books and journals
Barer, M.R. and Irving, W.L., 2018. Medical Microbiology E-Book: A Guide to Microbial
Infections. Elsevier Health Sciences.
Leber, A.L., 2020. Clinical microbiology procedures handbook. John Wiley & Sons.
Murray, P.R., 2017. Basic Medical Microbiology E-Book. Elsevier Health Sciences.
Birnie, K., Hay, A.D. 2017. Comparison of microbiological diagnosis of urinary tract infection in
young children by routine health service laboratories and a research laboratory:
Diagnostic cohort study. PloS one, 12(2), p.e0171113.
Vik, I., Bollestad, M. 2018. Ibuprofen versus pivmecillinam for uncomplicated urinary tract
infection in women—A double-blind, randomized non-inferiority trial. PLoS
medicine, 15(5), p.e1002569.
Dhungana, J.R. 2019. Urinary Tract Infection among Patients Visiting Ganesh Man Singh
Memorial Hospital and Research Center, Lalitpur, Nepal. Tribhuvan University Journal
of Microbiology, 6, pp.108-112.
Babich, T., Zusman, O. 2018. Replacement of urinary catheter for urinary tract infections: a
prospective observational study. Journal of the American Geriatrics Society, 66(9),
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Jiang, Y., Liu, Z., Ma, S. and Lv, J., 2018. Comparative study of different inoculation methods
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Oba, P.M., and et. al., 2020. Effect of a novel animal milk oligosaccharide biosimilar on the gut
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Shimizu, K., and et. al., 2020. Fecal Gram staining of phagocytosed bacteria to differentiate
methicillin-resistant Staphylococcus aureus: A case report. Journal of Infection and
Chemotherapy, 26(10), pp.1078-1081.
Raddaoui, A., and et. al., 2018. Description of a novel mutation in the atpC gene in optochin-
resistant Streptococcus pneumoniae strains isolates from Tunisia. International journal of
antimicrobial agents, 51(5), pp.803-805.
Woodford, N., 2018. Prevalence of carbapenem resistance and carbapenemase production among
Enterobacteriaceae isolated from urine in the UK: results of the UK infection-
Carbapenem Resistance Evaluation Surveillance Trial (iCREST-UK). Journal of
Antimicrobial Chemotherapy, 73(3), pp.698-702.
Al Zuhairi, J.J.M.J., 2020. Antioxidant, cytotoxic and antibacterial activity of Rosmarinus
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Journal of Integrative Medicine, 38, p.101192.