Bacteriology testing involves growing bacteria on special growth media. The medium usually used to grom the bacteria is agar. Agar usually has ingredients added to it to encourage bacteria to grow, a typical example of this is sheep blood, which provides nutrients to the bacteria while they are growing. When the bacteria are added to the media, they are usually placed in an incubator set at warm temperature, the reason being that bacteria multiply faster when they are kept in a warm environment. Some bacteria are anaerobic, and these may need to be kept in a reduced oxygen environment, this is achieved by placing them in an incubator with an increased level of carbon dioxide.
Once the bacteria have been allowed to culture they are examined so that the type of bacteria present can be identified. There are a number of ways in which bacteria can be identified, one is by looking at the appearance (morphology) of the bacterial colony (groups of bacteria) growing on the agar. The bacteria can be stained and examined under the microscope to see whether they are gram-positive or gram-negative , other biochemical tests can be carried out, as can more advanced identification methods such as PCR or Maldi-tof.
Once the bacterial “isolates” have been identified they can then be grown in growth medium to allow antimicrobial sensitivity testing to be carried out. Use of antimicrobial sensitivity testing allows vets to decide the most appropriate antibiotics to use when treating bacterial infections. The use of bacteriology testing and antimicrobial sensitivity testing is a prudent step in the use of evidence based medicine to help reduce the development of antimicrobial resistance (AMR)
Equine bacteriological culture
FarmLab carries out range of bacteriology tests on equine samples. Many of these are associated with reproductive assessment of mares and stallions pre-breeding or during the breeding season.
Best practice in equine reproductive management involves ensuring that mares and stallions are free of critical venereal organisms before they are allowed to mate. For this reason mares and stallions should be screened for Contagious Equine Metritis Organism (Taylorella equigenitalis) , Klebsiella pneumoniae and pseudomonas aeruginosa pre-breeding, this is in accordance with the recommendations of the Irish Thoroughbred Breeders Association, and more information relating to this can be found on their website here. FarmLab Diagnostics are an approved laboratory by the Department of Agricufor the testing of pre-breeding swabs from mares and stallions for CEM.
In addition to pre-breeding screening, mares are often checked to see if their uterus is free of infection or “clean”, especially if they have experienced problems being successfully mated in the past. This procedure involves a vet taking a swab from the mare’s cervix. This swab is then sent to the lab for culture and sensitivity testing. In many cases this will result in no growth, ie. the mare does not have an intrauterine infection. However in some cases a variety of organisms may be cultured, this means that the mare has endometritis , these can range from streptococci or coliforms to yeasts or fungi. Once isolated the organisms are checked to see which treatments are effective in killing the organism, and so can be used in deciding on the correct course of treatment with the mare
Salmonella can cause a range of diseases in all animals, this can include abortion in cattle and sheep, diarrhoea/colitis in horses / septicaemia in newborn animals. Special media are required to effectively culture salmonella, which can take up to 72 hrs. Once salmonella is confirmed in submitted samples the owner of the animals needs to work closely with their vet to implement control measures on the farm.