Sss222 Corrected v2

7/30/2019 Sss222 Corrected v2

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Introduction

Various infectitios diseases can be produced from ingestion of pathogens. These are

either probably cramped to gastrointestinal tract or initiated in the gut before scattering to

other parts of the body. However, there are numerous microbial pathogens that are able to

infect the gastrointestinal tract. These microbial pathogens can be identified and

segmented into different categories based on their size, characteristics and so on. Bacteria

are the most common microbes; after all, they cause gastrointestinal tract infection. They

can be got hold of by the fecal-oral route through fecal-contaminated food, water and

fingers. The pathogens must usually be ingested in sufficient number so that it can cause

to infection. There are several terms of indications used to describe the gastrointestinal

tract infection. Like gastroenteritis, diarrhea, dysentery, enterocolitis etc.

Gastroenteritis can be distinguished by gastrointestinal symptoms, for instance,

nausea, vomiting, diarrhea and abdominal discomfort. Salmonella, Shigella,

Staphylococcus, Campylobacter jejuni, Clostridium, Escherichia coli and yersinia

are the most common species of bacteria that cause gastroenteritis.

Diarrhea refers to blood or mucus in the stool may mean inflammatory bowel

disease or bacterial infection. Moreover, it occurs due to loose bowel movements

with bloating or flatus are often caused by lactose (in nonfermented dairy

products) or complex carbohydrates (often found in beans).

Dysentery is an inflammation of the intestine characterized by the frequent

passage of feces, usually with blood and mucus. The two most common causes of

dysentery are infection with a bacillus of the Shigella group, and infestation by an


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ameba, Entamoeba histolytica. Pain, fever, and abdominal cramps are symptoms

of this disorder and usually resulting from large intestine disease.

Enterocolitis is an inflammation involving the mucosa of both the small and large

intestine (1).

All of these terms are beneficial in identifying the cases and come to conclusion with an

effective outcome. The clinical history of the patient as usual plays an important role to

make the diagnosis effectively on track and maintaining towards right procedures. For

example, there were three cases that we had to investigate:

Case #1:

Along with 2 days history of gastroenteritis a16-year old boy was presented to the

doctor, his symptoms were nausea, vomiting followed by abdominal pains and

diarrhea. Those information were enough to go for diagnosis because it seemed to be

one of the pathogens that cause gastrointestinal symptoms.

Case #2:

the patient was suffering from fever, night sweat, severe headache and non productive

cough. There was also a history for a cluster of cases of typhoid fever occurred in the

country side of patient. These symptoms and history would give hint that the case

supposed to be salmonella typhi although we could not exclude other species unless

we had gone for further investigations.

Case #3:

A 22-year old patient was presented to the local doctor with a history abdominal

pains, fever and watery diarrhea followed by classical dysentery including blood and

mucus in his/her stool. These symptoms were typical for the third categorical


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description (dysentery) and doing further investigations were suggested to reach the

final diagnosis.

Clinical history is the great tool to enhance the opportunity and chance of absolute test

function and procedure to generate a meaningful and satisfactory outcome to represent in

front of the doctor to step into next phase for his patient. After all, clinical history is the

reflection of patients symptoms. It is very important to get the correct diagnosis of the

case to can prescribe the treatment accurately; this will help the patient to recover

quickly, moreover avoiding any complication of the disease. Therefore, to rashes that

identifying the above organisms by examining their gram morphology and colony

characteristics, with prime importance being given to simple biochemical tests, aims of

the practical exercises is to provide practical knowledge and skills to work at graduate

level in a diagnostic laboratory on the Enterics bench. Undoubtedly, to work most

effectively in order to interpret results and troubleshoot, it is essential for scientists to

understand the basic principles of diagnostic microbiology and recognizing and selecting

potential pathogens in mixed culture. However, a good understanding of microbial

pathogenesis is becoming increasingly important with the use of tests to detect potential

virulence factors, e.g. toxins.

Discussion

While working in the lab, we had gone through three organism which were unknown to

us; meanwhile, we finally managed to isolate them through proper identification

successfully. After all, as we know, there is no other best possible way rather than


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isolating organism through its accurate detection and identification. During this isolation

procedure, we did mark properly and made sure that is not ging to affect other with its

any kind of infected mode of effects. However, pathogens all kinds of investigation of

sampling work require to follow certain procedure and executing all of them correctly.

That is why, it is obvious and definite to maintain this standard from the beginning till

the last stage of its procedure; for example, history collection to the stage of result

generating stage. In this case, the first hit is the foundation of any furher steps; that

means, if there is anything wronly recorded or mentioned in the clinical history, then

automatically, it will create a barrier to generate a realistic and true outcome. So for lab

scientist the first important thing in the lab after consider the clinical not was the

selection of right media, for example, in case study one, no growth on the plate of

skirrows medium (SK) would exclude campylobacter spp, whereas the growth of bacteria

on desoxycholate citrate agar (DCA), xylose lysine desoxycholate agar (XLD) and

hektoen agar (HEK) would rule in salmonella and shigella spp. The morphological

features might give a clue of the suspected bacteria. For the sake of differentiation in

between salmonella and shigella, we had to undergo through biochemical test and in

response we explored salmonella spp. In addition, API 10S and serology were supposed

to give the exact serotype and if then sending the report to the reference lab for the

confirmation that would be more accurate to reach the correct identification. In case #1, it

was pretty good, nothing was surprising and all the outcomes were familier to us. There

were similarity between case #1 and case #2 outcomes; the only exception was in gas;

from glucose the gas was showing negative outcome; as a result, there was a

differentiation in between salmonella typhi and other salmonella serotypes. Ornithine


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decarboxylase was identified due to reverse response in between salmonella typhi and

other salmonella serotypes (3). Urea gave us a bit hectic moment with its unusual

outcome; from the second colony that had been choosen from the media, it showed its

response as positive. Therefore, we thought of its reflection on non pathogenic disorders;

as a result, it was excluded.

In case #3, the selective media, morphological features and biochemical tests were

reflecting more likely shigella spp. The serology test did represent a positive response

with shigella flexneri. In this practical exercise, we did choose two colons in each case

study; because, we saw slightly different colonies with size from what we normally

suspected in these cases. So in case #1, we did choose two colonies from XLD agar; first-

one was red colonies with black center and the second-one was red colonies very small in

size to be more accurate in identifying the bacteria; but the result was the same for the

both colonies that had been picked. But in case #2 we did choose two colonies but the

result was different. In case #2, two different colones was first choosen from HEK agar

which was green most raised colonies and the second-one was blue green colonies with

black center and the result were the same for both colonies exabte in urea test was

positive in the second colony and negative in the first-one; so we excluded the second

colony; because it was might reflect non pathogenic disorders and that thing was not in

our interest in this practical exrsaus. Finally, in case #3, we also did choose two different

colonies first one from XLD agar red colony and green colonies from HEK agar and the

result were different from each other as it shown in table 3 above but we excluded the

second colonies because it gave us positive urea test and that reflect non pathogenic

disorders. The purity plat for all cases were checked and it was pure with no other


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bacteria growth but if it was not pure all the biochemical test could not be readied and

that would also mean that we were needed to do the exrsaus from the beginning.

Moreover, infectivity of the specimens also did carry wrong diagnosis. That is why extra

measures were taken before any steps initiated, especially the cleanliness was in the

priority. Flame played a major role to avoid any kind of giving chance of allowing

infectivity during the working hours in the lab.

In the end, it can be shared that all the procedures during the tests and throughout this

case study were followed accurately or atleast tried to be acurate. Undoubtedly, we had to

follow the appropriate steps in a right time with right justifications rather than making the

situation in a twisted-manner. Often, we realized that prper time management and usage

of its best in a systematic way would have given us more confidence on claiming the true

and accurate outcomes of any results; but still we are hopeful with our approach and

mode of operations.

After analyzing all the above facts and figures, throughout the experience, we would like

to recommend the followings as per our understanding:

While doing all the tests, it is very essential to keep all the information and data.

Therefore, recording all the data properly is must. Moreover, we assume, tests

must be conducted in a sequential and systematic manner.

Organism is the key factor to generate result or come up with a conclusion;

sometimes or often the result can frustrate us through its positivity or negativity.


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To be well organsied and uptodated with the standard of procedure, time is the

key factor; it is understandable that the free of time usage can provide us that

opportunity in generating best result.

Sss222 Corrected v2

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