MICROBIOLOGY TESTS

The purpose of performing Microbiology tests is to detect the germs that cause infectious diseases.

Infectious diseases are diseases caused by Germs (Microorganisms) or their products such as toxins. Infectious diseases are the number one cause of the disease burden in Africa, and are responsible for most of the illness and death on the continent. Infectious diseases may be caused by bacteria, viruses, parasites or fungi. In table 1, examples of infectious diseases and the germs/ organisms causing them are shown.

Infectious diseases diagnostics thus involve the detection of the disease-causing germs/microorganisms in patient samples and/or testing of these germs / organisms to a profile of antibiotics to determine the exact antibiotics that kill the germ/organism before the doctor prescribes for you the correct antibiotic that will work.  When the germs are grown in the laboratory and tested against the antibiotics to tell which ones kill them, this process is known as Culture and Sensitivity Testing.

Table 1. Examples of infectious diseases and their causative organisms

Organism group Infectious Disease Example of causative Germs/organisms
Bacteria Pneumonia

Streptococcus pneumonia

Urinary tract infections (UTI) Escherichia coli, klebsiella pneumonae
Skin ulcers in children Streptococcus pyogenes
Otitis media Staphylococcus aureus, haemophillus influenzae
Tuberculosis  (TB) Mycobacterium tuberculosis
Typhoid Salmonella Typhi or Paratyphi
Syphilis Treponema pallidum
Brucellosis Brucella mellintensis or B. Abortus
Dysentery (bloody diarrhoea) Shigella dysenterae
Bacterial Meningitis Streptococcus pneumoniae, Nesseria meningitidis
Peptic ulcers Helicobacter pyroli
Pyomyositis Staphylococcus aureus
Osteomyelitis Staphylococcus aureus
Gonorrhea Nesseria gonorrhae
Blood stream infection Staphylococcus aureus, salmonella spp
Viruses Naso-pharyngitis (Sore throat/flu) and pneumonia SARS-CoV-2 Virus (COVID-19), Influenza, Measles, etc
AIDS HIV
Painful ulcers in genital parts Herpes simplex virus (HSV) Type 2
Genital warts Molluscum contagiosum
Viral Meningitis Herpes simplex virus (HSV) type 1
Blood stream viral infections Cytomegalovirus (CMV)
Skin infections Molluscum contagiosum
Fungi Nails/Hair/Skin fungal infections in children/adults Many species of fungi cause these
Vaginal candidiasis Candida albicans
Blood stream fungal infections Candida albicans – in patients with blood/bone marrow cancer
Fungal Meningitis Cryptococcus neorfomans
Disseminated organ fungal infections Several Dimorphic fungi
Parasites Malaria Plasmodium falciparum or other species
Intestinal hookworm disease Hook worms
Intestinal tape worm disease Taenia saginata,  or T solium
Trypanosomiasis Trypanosoma gambience
Filariasis (River blindness or Elephantiasis) Oncocerca volvulus
Schistosomiasis Schistosoma haematobium, S. Mansoni
Persistent Diarrhoea Cryptosprodium parvunm or other species

Due to the worldwide growing problem of drug resistance, it is very critical that the patient caring doctor gets to know exactly the organism in the patient sample, and its drug susceptibility profile thru culture and sensitivity testing.

MBN Clinical Laboratories offers, seamlessly and professionally, culture and sensitivity testing services, and also performs molecular/DNA-based tests to help determine the causative germs and their susceptibility to antibiotics.

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SAMPLE & MICROBIOLOGY TESTS

 

Ascites/Pleural/Joint/Pericardial/Hydrocele Fluids (10-20 mls in sterile tube)

Cell counts, Gram, ZN, Protein, Sugar, LDH

Culture & Sensitivity

 

Biopsy tissue

Gram and ZN stain

KOH + Calcoflour (fungal hyphae)

Culture & Sensitivity (Sample collected in plain sterile container with 1-2 mls sterile N.saline)

Histopathology test, collect sample in 10% Formalin

Pap Smear to screen for cancer of the Cervix

 

Blood

B/S Malaria/Trypanosoma/Filaria/Leishman)

Malaria antigen test (P. falc & P. ovale )

Blood culture & Sensitivity – Manual monitoring

Blood culture & Sensitivity – Automated monitoring

 

Bone marrow (1-2ml in sterile tube)

Bone marrow Smear/film

Culture & Sensitivity (bacteria / fungi)

 

Breast milk (5-10ml in sterile tube)

Gram, ZN stain, Culture & Sensitivity

 

BAL/Endotrachael fluid (3-5 mls in sterile tube)

Gram, ZN and Auramine stain

Giemsa stain (Pneumocyctis jirovecii/PCP)

Culture & Sensitivity (bacteria / fungi)

Mycobacterial Culture & Sensitivity

 

Catheter Tip (2-3cm tip, cut into 1ml sterile N/S)

Culture & Sensitivity (bacteria / fungi)

 

CSF  (1-3ml in sterile tube, 1ml in Fluoride bottle for Sugar)

Cell counts – T & D, India ink, Gram & ZN stain, Sugar, Protein

Culture & Sensitivity (bacteria / Yeasts e.g. Cryptococcus)

RPR/ VDRL and TPHA with titers

CRAG (Cryptococcal antigen) test

 

Corneal Scraping (In Sterile tube/petridish)

Gram, ZN, KOH+Calcoflour white stain

Culture for ameoba

 

High Vaginal /Cervical Swab

Wet prep for TV, & Gram stain for clue cells

Culture & Sensitivity(Grp B strep or Neisseria)

 

Gastric Aspirate/biopsy (3-5 mls or g in sterile tube)

ZN for AFBs

Culture for Helicobacter pylori or Mycobacteria

 

Lymph node Aspirate (3-5 mls in sterile tube)

Gram, ZN and auramine stain

Culture & Sensitivity (bacteria / fungi)

Mycobacterial Culture & Sensitivity

 

Nasal swab (in amies transport medium)

Culture & Sensitivity to r/o MRSA

 

Nasopharyngeal/Oropharyngeal swab (in amies transport medium)

Direct Agglutination test (Group A β–haem strept)

Culture & Sensitivity (Group A β-haem strept)

 

Pus 2-3ml in sterile tube or pus swab in amies transport medium. Body site:__________

Gram & ZN stain, Culture & Sensitivity  (bacteria / fungi)

Anaerobic Culture & Sensitivity (only for pus in tube)

 

Semen

Volume, PH, Spermatozoa motility, Morphology, Count

Culture & Sensitivity

 

Skin/Hair/ Nail Scrapping (in sterile petri dish)

KOH+ Calcoflour white stain (fungal hyphae/ yeasts)

Culture & Sensitivity for fungal diagnosis

 

Sputum – Coughed out/Induced (≥3ml, sterile tube)

Gram, ZN and Auramine stain

Giemsa stain (Pneumocyctis jirovecii/PCP)

Culture & Sensitivity (bacteria / fungi)

Mycobacterial Culture & Sensitivity

 

 

Stool 3-5g or mls in sterile dry tube; (If for O&P, put in 10ml of 10% Formalin)

Direct wet/iodine mount microscopy

Processed stool then iodine mount microscopy, Trichrome staining for Ova&Parasites and Modified ZN for protozoa such as Cryptosporidium oocysts)

Methylene blue test for PMN Cells

Culture & Sensitivity (Salmonella/Shigella/C.jejuni/Yersinia/Enterohaemorrhagic E. coli/H. pylori/Vibriocholerae)

Reducing sugars in stool

Sudan III test for stool fat

 

Urethral/Rectal Swab (collect into Modified Thayer-Martin medium or inoculate a chocolate plate immediately).

Gram, ZN stain, Culture & Sensitivity

 

Urine (5 -10mls in sterile tube)

Microscopy (WBCs, RBCs, epithelial cells, casts, eggs)

Gram & ZN stain on sediment

Culture & Sensitivity