Bacteriology/Parasitology Section
Surveillance and Monitoring
South
Carolina law requires the monitoring of certain bacterial and parasitic
diseases.
Laboratories isolating organisms of public health importance can send them
to the Bacteriology Laboratory for identification or confirmation.
The Bacteriology Laboratory maintains antisera for the serogrouping of :
- Neisseria meningitidis Groups A, B, C, X, Y, Z, W135
- Haemophilus influenzae Groups A, B, C, D, F
- Escherichia coli O26
- Escherichia coli O157:H7
- Escherichia coli O111
- Vibrio cholerae O1, Inaba and Ogawa strains
- Vibrio cholerae O139
- Shigella groups A, B, C, D
- Streptococcus Lancefield groups A, B, C, D, F, G
Antisera are also available for the serogrouping and serotyping of Salmonella. Serogrouping and serotyping of bacteria provide important epidemiological information necessary to monitor the spread of diseases. These procedures allow a cluster of similar bacteria to be recognized and investigated before it can mushroom into a full-scale outbreak.
DHEC's division of Communicable Disease Control and the Bureau of Laboratories have requested that isolates of H. influenzae and N. meningitides from normally sterile body sites be referred to this laboratory for serogrouping. All isolates of Salmonella, E. coli O157:H7, Vibrio cholerae, Shigella, invasive strains of beta hemolytic Streptococcus group A (S. pyogenes), Listeria monocytogenes and Campylobacter are requested. Fecal isolates of E. coli that fail to ferment sorbitol can be sent for screening for the presence of O157 and H7 antigens. The Division of Laboratories publishes a Laboratory Services Guide (pdf) which provides detailed information on how to submit specimens.
Reference Services
The Bacteriology and Parasitology Laboratory serves as the reference laboratory for South Carolina. Bacterial isolates from clinical laboratories can be referred for identification, confirmation or quality assurance. Identification of these organisms is accomplished using conventional biochemical techniques and special stains such as spore, flagella and fluorescent antibody. Determination of metabolic end-products using gas liquid chromatography is also included in the identification of various anaerobes and certain aerobic bacteria.
BACTERIOLOGY
- The Enteric Unit identifies members of the Enterobacteriaceae, Campylobacter
species, Vibrios and other enteric organisms. These organisms, while often
found in fecal specimens, can also cause a variety of serious infections
in other parts of the human body.
- The Special Medical Unit identifies a variety of highly unusual pathogens
that have very varied growth requirements. Haemophilus, Brucella, Bordetella,
Pseudomonas and Listeria species are among the hundreds of different species
identified by this unit.
- The Anaerobe Unit identifies bacteria that cannot live in the presence
of oxygen. These bacteria require very special media and processing to
protect them from exposure to air. Bacteroides, Clostridium, Actinomyces
and Peptostreptococcus species are among the anaerobes most frequently
identified.
- The Gram Positive Coccus Unit identifies aerobic cocci such as Staphylococcus,
Streptococcus, Micrococcus, Leuconostoc, Gemella and Abiotrophia. This
unit also receives swabs from prenatal clinics for culture of beta hemolytic
Streptococcus group B (Streptococcus agalactiae). Detection and treatment
of Group B Streptococcus in pregnant women prior to delivery can help prevent
a form of meningitis which can result in birth defects or death of newborn
infants.
- The Gonorrhea Unit isolates Neisseria gonorrhoeae. This unit uses culture methods rather than direct detection with a genetic probe for determining the presence of gonorrhea. Culture methods of identification are necessary when isolating N. gonorrhoeae from extra-genital body sites or from children or adults for whom treatment with antibiotics has failed to eradicate the disease.
PARASITOLOGY
The Parasitology area receives fecal material for concentration, staining and microscopic examination for ova and parasites. Cyst forms, helminth eggs and larvae, such as hookworm , are detected through microscopic examination of a concentrated suspension of feces in Burke's modification of Gram's iodine. Trophozoites are detected and identified using a trichrome stain. Cyclospora are detected by acid-fast stain. Chromotrope 2R stain is used to identify Microsporidia. Fluorescent antibody stain or acid-fast stain is used to identify Cryptosporidia.
Giardia lamblia is the pathogenic parasite seen most frequently in South Carolina. A fluorescent antibody stain is available which can detect cysts of both Giardia and Cryptosporidium. Cysts of Giardia are also identified by microscopic examination of an iodine treated concentrate while Trophozoites forms are identified using a trichrome stain.
Babesia or Plasmodium can be detected by microscopic examination of blood smears stained with Giemsa stain. They are blood-borne parasites that can be transmitted by the same tick that carries lyme disease. Transmission of this disease occurs naturally in the United States especially in the northeastern coastal region. Plasmodium species are the causative agents of Malaria. Most cases of malaria seen in South Carolina have originated outside of the United States.
Investigation of Outbreaks
Clusters of parasitic or bacterial illnesses indicating a possible outbreak requires a rapid response in order to prevent the further spread of infection. This laboratory's staff are trained to provide such a response. The staff works very closely with the DHEC Division of Communicable Disease Control and The Centers for Disease Control and Prevention in Atlanta in order to identify the causative agent, its origin and the extent of its spread.