Automated colony pickers are the equipment that helps pick the desired colony from a cluster of different colonies from any culture media.
Moraxella catarrhalis is a small gram-negative diplococci that resembles Neisseria and causes otitis media in children.
Dark field microscopy is the most specific and sensitive technique to diagnose syphilis when an active chancre or condyloma lata is present.
Presence of bacteria in sterile body fluids, isolation of Mycobacterium tuberculosis or any other bio-terrorism agents should be reported immediately.
Clerical errors, inappropriate containers/conditions, inappropriate or inadequate specimens, delay in transit lead to sample rejection.
Bacteroides fragilis is a gram-negative, pleomorphic anaerobe responsible for variety of anaerobic infections including peritonitis.
Actinomyces is a heterogeneous group of gram-positive, pleomorphic bacilli responsible for the disease actinomycosis.
Francisella tularensis is a gram-negative coccobacillus and is the etiologic agent of tularemia. It is transmitted to humans from rodents and rabbits.
Burkholderia pseudomallei is a water- and soil-borne gram-negative bacterium. Causative agent of melioidosis, it is regarded as a potential bioterror agent.
Nocardia species are gram-positive, variably acid-fast, filamentous, and strictly aerobic organisms belonging to the actinomycetes group.
Legionella is a gram-negative pleomorphic rod, responsible for a serious type of pneumonia called Legionnaires' disease.
Ziehl-Neelsen staining, culture in Lowenstein-Jensen medium and GeneXpert MTB/RIF assay are useful methods for the diagnosis of tuberculosis.
Gram positive club shaped (chinese letter form) bacteria responsible for diphtheria.
Commensal in the large intestine of humans and is responsible for the disease, gas gangrene.
Gram positive, obligate anaerobe, looks like drum-stick shaped and causes tetanus.
Gram positive, anaerobic rod which produces powerful neurotoxin "botulinum toxin".
Yersinia pestis is a short gram-negative rod, responsible for deadly zoonotic disease, plague.
Dark-field microscopy is used for the observation of living, unstained cells. The specimen is brightly illuminated while the background is dark.
A potential biological weapon which causes important zoonotic disease called anthrax.
Streptococcus agalactiae (GBS), is a beta-hemolytic, CAMP test positive, gram-positive cocci. It can cause severe infection in newborns.
BACTEC by BD diagnostics utilizes fluorescent technology and detects the growth of organisms in the blood culture bottles.
Detection of specific antigens present in the sample (blood, urine, or CSF) using specific antibodies is the mainstay for the rapid diagnosis of infections.
Leptospirosis is diagnosed using dark-field microscopy, microscopic agglutination test (MAT) or using IgM ELISA.
This smallest free-living bacteria does not have cell wall (so pleomorphic in shape) causes walking pneumonia.
This gram-negative capsulated rod-shaped bacteria causes hospital acquired pnuemonia, UTI and blood stream infection.
Pus aspirate is the preferred sample. S. aureus, Strep pyogenes, and members of Enterobacteriaceae are major pathogens.
MALDI-TOF MS offers species-level identifications in minutes at low costs with accuracy that matches or even exceeds the conventional system.
The overall volume of blood cultured is more critical in increasing organism yield. More the blood volume cultured greater the chance of isolating pathogen.
Physicians may prefer blood culture in a number of suspected disease conditions such as enteric fever, infective endocarditis, meningitis, pneumonia, etc.
Pneumococcal urinary antigen testing is a rapid assay that detects Streptococcus pneumoniae antigen (C-polysaccharide) in the urine of patients.
Patients swallow 14C-urea capsule. Test urea will be broken down, if infected, and a lot of 14CO2 produced which is detected in the breathe.
Cary-Blair transport medium is used to transport clinical specimens suspected to contain enteric pathogens, including Shigella, Salmonella, Vibrio.
Haemophilus species require accessory growth factors such as X (hemin), V (NAD) or a combination of both.
M. tuberculosis gives rough, raised, dry, non-pigmented (cream/buff colored) colonies on Lowenstein Jensen (LJ) medium.
TPHA is a treponemal test for the serologic diagnosis of syphilis, based on the principle of passive hemagglutination. It detects IgG and IgM.
To diagnose H. pylori infections, urea breathe test, fecal antigen test and rapid urease test are most widely used.
GeneXpert MTB/RIF assay is a NAAT that simultaneously detects DNA of M.tuberculosis complex and resistance to rifampin (i.e. mutation of the rpoB gene).
Quellung reaction is the gold standard technique for serotyping S. pneumoniae. Capsule get “swollen” and is more visible.
Widal test is one of the oldest and most widely used serological tests for the diagnosis of enteric fever.
Gram positive obligate anaerobe responsible for a unique colonic disease, pseudomembranous colitis.
Elek test is an in vitro immunoprecipitation test to determine whether or not a strain of Corynebacterium diphtheriae is toxigenic.
This group A beta-hemolytic streptococci is bacitracin sensitive and causes strep sore throat, rheumatic fever, and PSGN.
Microdase test is a rapid method to differentiate Staphylococcus aureus (negative) from Micrococcus luteus (positive).
Tuberculin skin test is the standard method of determining whether a person is infected with M.tuberculosis or has exposure to tubercle bacilli.
Rapid test for identifying Moraxella (Branhamella) catarrhalis which produce butyrate esterase enzyme.
In Schaeffer-Fulton`s method, primary stain-malachite green is forced into the spore by steaming the smear, safranin is counterstain.
API-20E test strip (from bioMerieux, Inc.) is used to identify the enteric gram negative rods.
In the presence of specific Abs to an infectious agent, any complement in the system is bound, leaving no residual complement for rxn with Abs to the RBCs.
Auramine-rhodamine fluorochrome staining also known as "Truant method of staining", is used to visualize Acid-fast bacilli (AFB).
Beta hemolytic streptococci are arranged into twenty (20) groups A-U without I and J (i.e. A through H and K through V).
Mycobacterium species possess an enzyme-lipase, that splits Tween-80 and releases oleic acid and polyoxyethylated sorbitol.
Common culture media are bismuth sulfite agar, MacConkey agar, deoxycholate citrate agar, xylose lysine deoxycholate agar, salmonella-shigella agar, etc.
V. cholerae emulsified in sodium deoxycholate, it lyses the cell wall and releases DNA giving a mucoid “string” when a loop is drawn away.
DNase test determines the ability of an organism to hydrolyze DNA.
The drop hangs from the coverslip, and the petroleum jelly forms a seal that prevents evaporation. This preparation gives good views of microbial motility.
Clean-catch midstream urine, suprapubic aspiration and straight catheter techniques are common method of urine sample collection.
Gelatin hydrolysis test determines the ability of an organism to produce gelatinases that liquefy gelatin.
Bile-esculin test is widely used to differentiate Enterococci and Non-enterococcus group D streptococci from non-group D viridans group streptococci.
Ziehl-Neelsen acid fast stain is designed to stain bacterial cells containing long chain fatty (mycolid acids) such as Mycobacterium.
Some gram-positive cocci such as Enterococcus produces enzyme L-pyrroglutamylaminopeptidase that hydrolyze PYR substrate.
Tran-isolate medium is used to inoculate and transport CSF sample, If the CSF cannot be transported to a microbiology laboratory immediately.
Rose Bengal test is a simple, rapid slide-type agglutination assay performed with a stained B. abortus to diagnose brucellosis.
Brucellosis, also known as “Undulant fever”, “Mediterranean fever” or “Malta fever” or “Bang’s disease” is a zoonosis caused by Brucella melitensis.
Cholera is an acute infection of the gut caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae O1 or O139.
A colony is defined as a visible mass of microorganisms. Colony characteristics of microorganisms help in their identification.
The first morning expectorated sputum sample is always best for the diagnosis of lower respiratory tract infections.
Modified Kirby-Bauer disc diffusion test method is a reference method to test the susceptibility of a bacterial isolate in a clinical laboratory.
Susceptible organism is likely to respond to treatment with this drug, at the recommended dosage but resistant wont respond.
Haemophilus spp may grow on sheep blood agar very close to the colonies of Staphylococcus aureus.
RPR test is a macroscopic, nontreponemal flocculation card test used to screen for syphilis. RPR test measures IgM and IgG antibodies to lipoidal material.
Rapid latex agglutination test for the qualitative and semi-quantitative determination of anti-streptolysin-O antibodies (ASO) in serum.
Common etiologic agents of acute meningitis are enteroviruses and bacteria (S. pneumoniae, Neisseria meningitidis, Haemophilus influenzae).
Gram-negative, oxidase-positive, coccobacilli, which requires X and V factors for the growth.
Gram positive diplococci (lanceolate shaped), alpha hemolysis, optochin sensitive and bile soluble isolates are S.pneumoniae.
Tests are; Tween-80 hydrolysis test, niacin test, nitrate reduction test, tellurite reduction test, urea hydrolysis test and citrate utilization test.
Neisseria gonorrhoeae is a gram-negative kidney-shaped diplococci. It causes gonorrhea, a sexually transmissted infection.
Syphilis is diagnosed by using dark field microscopy, non-treponemal tests (VDRL, RPR) or treponemal tests (TPHA, FTA-ABS).
FTA-ABS is an indirect fluorescent antibody technique used as a confirmatory test for syphilis. FTA-ABS is the first serological test to become positive following infection.
Chlamydia trachomatis, is an obligate intracellular bacteria which causes pelvic inflammatory disease and other infections (e.g. eye).
The causative agent of Bacillary dysentery, Shigella is a member of family Enterobacteriaceae. It is non-motile, non-lactose fermenter.
The most common cause of gastroenteritis worldwide, Campylobacter is a curved, gram-negative rod. It is an oxidase-positive microaerophile.
Optochin (ethylhydrocupreine hydrochloride) lyses pneumococci (positive) but alpha-streptococci are resistant (negative).
Bacitracin test differentiates S. pyogenes (inhibited) from other beta-hemolytic streptococci.
Pneumococcus is lanceolate shaped gram-positive cocci and causes pneumonia and meningitis. Its is optochin sensitive and bile soluble.
Characteristics pigmentation observed in the culture media is because of the changes in the pH of the medium.
Frequent colonizer of skin, S. aureus is a major cause of surgical wound infection. This gram-positive cocci is catalase and coagulase +ve.
Normal flora of GI tract, E.coli is a major cause of urinary tract infections. It is lactose fermenting, gram negative bacilli.
Gram negative rods, catalase positive and oxidase positive. It produces pigments (pyocyanin and pyoverdin).
We can not culture T. pallidum, M. leprae, Chlamydia trachomatis, Coxiella burnetti and Rickettsia in in-vitro culture media.
Also known as Hansen’s disease, leprosy is a chronic infectious disease caused by an acid-fast bacillus, Mycobacterium leprae.
Coagulase test detects clumping factors and bound coagulase and differentiates Staphylococcus aureus (positive) from CoNS (negative).
