MICROBIOLOGY TESTS
The purpose of performing Microbiology tests is to detect from the patient sample the germs that cause infectious diseases. The techniques used to do this include Culture and Sensitivity testing, PCR/Molecular Diagnostics techniques, microscopy, serology or antigen detection techniques.
Culture and Sensitivity.
When the patient sample is inoculated on a growth plate in the laboratory with the germs are allowed to grow and then tested against the antibiotics to tell which drugs kill them or stop them from growing, this process is known as Culture and Sensitivity Testing. Example is in urine culture and sensitivity to detect the bacteria which cause UTI (Urinary Tract Infections).
PCR/Molecular Diagnostics.
Sometimes, we look for the DNA or RNA of the disease-causing germ in the patient sample using PCR/Molecular Diagnostics techniques. Example is TB PCR on sputum, HIV PCR on blood, Hepatitis C virus PCR on blood, COVID-19 PCR on Nasopharyngeal samples, e.t.c.
Other techniques.
Still other times we simply detect the germs through microscopy e.g. for malaria germs in blood, serology or antigen techniques.
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.
| 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 |
The MBN Automated Blood Culture System on the BACTEC FX40 Instrument
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