Agar Plate

MacConkey agar

 Macconkey agar with lactose (left) and non-lactose (right)

A MacConkey agar plate with an active bacterial culture.

MacConkey agar is a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation.

 Contents

It contains bile salts (to inhibit most Gram-positive bacteria, except Enterococcus and some species of Staphylococcus i.e. Staphylococcus aureus), crystal violet dye (which also inhibits certain Gram-positive bacteria), neutral red dye (which stains microbes fermenting lactose), lactose and peptone.
Composition:

• Peptone - 17 g
• Proteose peptone - 3 g
• Lactose - 10 g
• Bile salts - 1.5 g
• Sodium chloride - 5 g
• Neutral red - 0.03 g
• Agar - 13.5 g
• Water - add to make 1 litre; adjust pH to 7.1 +/- 0.2

There are many variations of MacConkey agar depending on the need. If the spreading or swarming of Proteus species is required, sodium chloride is omitted. Crystal violet at a concentration of 0.0001% (0.001 g per litre) is included when we need to check if Gram-positive bacteria are inhibited.

 History

The medium was developed by Alfred Theodore MacConkey while working as a bacteriologist for the Royal Commission on Sewage Disposal.

Uses

Acting as a visual pH indicator, the agar distinguishes those Gram-negative bacteria that can ferment the sugar lactose (Lac+) from those that cannot (Lac-).
This medium is also known as an "indicator medium" and a "low selective medium". Absence of electrolytes serves to inhibit swarming by Proteus species.

 Lac+

By utilizing the lactose available in the medium, Lac+ bacteria such as Escherichia coli, Enterobacter and Klebsiella will produce acid, which lowers the pH of the agar below 6.8 and results in the appearance of red/pink colonies. The bile salts precipitate in the immediate neighborhood of the colony, causing the medium surrounding the colony to become hazy.

Lac-

Non-Lactose fermenting bacteria such as Salmonella, Proteus specis, Pseudomonas aeruginosa and Shigella cannot utilize lactose, and will use peptone instead. This forms ammonia, which raises the pH of the agar, and leads to the formation of white/colorless colonies formed in the plate. But they can also look golden to brown with dark centers. They are circular colonies and arranged randomly.

 Slow

Some organisms ferment lactose slowly or weakly, and are sometimes put in their own category. These include Serratia and Citrobacter

 Variant

A variant, Sorbitol-MacConkey agar, (with the addition of additional selective agents) can assist in the isolation and differentiation of enteropathogenic E. coli serotypes such as E. coli O157:H7, by the presence of white circular colonies that are non-sorbitol fermenting.

Endo agar

 
Endo agar (also called Endo's medium) is a microbiological growth medium with a faint pink colour. Originally developed for the isolation of Salmonella typhi, it is now used mostly as a coliform medium. Most gram-negative organisms grow well in this medium, while growth of gram-positive organisms is inhibited. Coliform organisms ferment the lactose in this medium, producing a red colour (i.e. Eschericha coli), whereas non-lactose-fermenting organisms produce clear, colourless colonies, i.e. Salmonella sp..

 Typical composition

Endo agar typically contains :

• 1.0 % peptone
• 0.25 % dipotassium hydrogen phosphate (K₂HPO₄)
• 1.0 % lactose
• 0.33 % anhydrous sodium sulfite (Na₂SO₃)
• 0.03 % fuchsine
• 1.25 % agar

Blood agar types

 

• Blood agar plate (BAP)

Contains mammalian blood (usually sheep or horse), typically at a concentration of 5–10%. BAP are enriched, differential media used to isolate fastidious organisms and detect hemolytic activity. β-hemolytic activity will show lysis and complete digestion of red blood cell contents surrounding colony. Examples include Streptococcus haemolyticus. α-hemolysis will only partially lyse(the cells are either lysed or not- it is the digestion that may be incomplete) the hemoglobin and will appear green. An example of this would be Streptococcus viridans. γ-hemolysis (or non-hemolytic) is the term referring to a lack of hemolytic activity.

Contains meat extract, tryptone, sodium chloride, and agar.

Mannitol salt agar

An MSA plate with Micrococcus sp. (1), Staphylococcus epidermis (2) and S. aureus (3) colonies.

Mannitol salt agar or MSA is a commonly used growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others. This medium is important in medical laboratories by distinguishing pathogenic microbes in a short period of time.  It contains a high concentration (~7.5%-10%) of salt (NaCl), making it selective for Staphylococci (and Micrococcaceae) since this level of NaCl is inhibitory to most other bacteria. It is also a differential medium, containing mannitol and the indicator phenol red. Coagulase-positive Staphylococci produce yellow colonies with yellow zones, whereas coagulase-negative Staphylococci produce small pink or red colonies with no color change to the medium. If an organism can ferment mannitol, an acidic byproduct is formed that will cause the phenol red in the agar to turn yellow.  It is used for the selective isolation of presumptive pathogen (pp) Staphylococci.

 

HEALTH EDUCATION MESSAGE

PENYULUHAN KESEHATAN

           

Kebersihan Pribadi

Mencuci Tangan

v     Cucilah tangan anda dengan sabun, abu, atau perasan jeruk nipis;

      Sebelum menyajikan makanan

      Sebelum anda makan atau memberi makan anak anda

      Setelah menggunakan toilet atau jamban atau memandikan anak.

v     Gunakan air bersih yang banyak

v     Bersihkan seluruh bagian tangan anda mulai dari depan, belakang, hingga sela-sela jari dan kuku 

v     Buatlah (jika belum punya) dan pergunakanlah toilet atau jamban di rumah anda.

v     Jagalah selalu kebersihan toilet atau jamban.

v     Buanglah kotoran dari bayi di toilet atau jamban.

Makanan

Masak, kelupas, atau tinggalkan saja (Cook it, peel it, or leave it)

      Masaklah bahan makanan hingga matang seluruhnya.

      Eat cooked foods immediately, while they are stile hot.

      Simpan masakan di kulkas secara hati-hati.

      Panaskan kembali makanan dari kulkas hingga seluruh bagiannya.

      Hindari mencampur makanan yang dimasak dari bahan mentah.

      Kupas kulit buah yang ingin anda makan

      Cuci dan bersihkan piring serta peralatan makan dan memasak yang telah anda gunakan.

Air Minum

Mengelola air minum

Ø      Rebus air hingga mendidih, atau gunakan khlorinasi sesuai ketentuan.

Ø      Simpan air minum yang telah dimasak di tempat yang bersih dan tertutup.

Ø      Air minum dapat digunakan dalam kurun waktu 24 jam

Ø      Tuang air ke gelas / botol, jangan menciduk air dari tempatnya.

Menjaga Sumber Air Minum

v     Jangan membuang air besar di dekat sumur atau sumber air minum lainnya

v     Jangan mandi atau menyiram tanaman atau aktifitas apapun hingga mengotori sumur atau sumber air minum lainnya

v     Tutup Sumur ketika tidak sedang digunakan

MACROSCOPIC URINALYSIS

           

The first part of urinalysis is direct visual observation. Normal, fresh urine is pale to dark yellow or amber in color and clear. Normal urine volume is 750 to 2000 ml/24r.

Turbidity or cloudiness may be caused by excessive cellular material or protein in the urine or may develop from crystallization or precipitation of salts upon standing at room temperature or in the refrigerator. Clearing of the specimen after adition of small amount of acid indicates that precipitation of salts is the probable cause of turbidity.

A red or red- brown (abnormal) color could  be from dye, eating fresh beets, a drug, or the presence of either hemoglobin. Or myoglobin. If the sample contained many red blood cells, it would be cloudy as well as red.

Example of appearance of urine..

Vitamin B₁₂

Vitamin B12, disebut juga kobalamin, adalah sebuah vitamin larut air yang berperan penting dalam berfungsi normalnya otak dan sistem saraf, serta dalam pembentukan darah. Vitamin ini merupakan salah satu dari delapan vitamin B. Umumnya, vitamin ini terlibat dalam metabolisme setiap sel dalam tubuh, terutama pengaruhnya pada sintesis dan regulasi DNA serta pada sintesis asam lemak dan produksi energi.

Vitamin B12 merupakan kumpulan senyawa-senyawa yang terhubung secara kimia, yang semuanya memiliki aktivitas sebagai vitamin. Secara struktur, vitamin B12 adalah vitamin yang paling kompleks dan mengandung elemen kobal yang jarang tersedia secara biokimia. Biosintesis dari struktur dasar vitamin ini hanya dapat dilakukan oleh bakteri, namun konversi antara bentuk-bentuknya yang berbeda dapat terjadi dalam tubuh. Suatu bentuk sintesis yang umum dari vitamin ini, sianokobalamin, tidak terjadi di alam, namun digunakan dalam banyak sediaan farmasi dan suplemen, dan juga sebagai bahan tambahan makanan karena kestabilannya dan harganya yang lebih murah. Dalam tubuh, vitamin ini diubah menjadi bentuk fisiologisnya, metilkobalamin dan adenosilkobalamin, dengan membuang gugus sianida nya walaupun dalam konsentrasi minimal. Baru-baru ini, hidroksokobalamin (suatu bentuk kobalamin yang dihasilkan dari bakteri), metilkobalamin, dan adenosilkobalamin juga dapat ditemukan pada produk farmakologi dan suplemen makanan yang mahal. Kegunaaan dari zat-zat ini masih diperdebatkan.

Dalam sejarahnya, vitamin B12 ditemukan dari hubungannya dengan penyakit anemia pernisius, sebuah penyakit otoimun yang menghancurkan sel-sel parietal dalam perut yang mensekresi faktor intrinsik. Faktor intrinsik ini sangat penting dalam absorpsi normal vitamin B12, sehingga kekurangan faktor intrinsik, yang tampak pada anemia pernisius, disebabkan oleh kekurangan vitamin B12. Sejak saat itu, banyak jenis-jenis kekurangan vitamin B12 lain yang lebih tidak kentara, berikut efek biokimianya, telah berhasil diuraikan.