The implementation of control measures for contagious mastitis pathogens has successfully reduced the prevalence of these organisms in U.S. dairy herds. However, the control of environmental pathogens remains a daunting task. Klebsiella spp. are Gram-negative bacteria, similar in structure to Escherichia coli. The most common, mastitis-causing species are Klebsiella pneumoniae and K. oxytoca, but treatment and control is similar for all species of Klebsiella.
Where Are These Organisms Found?
These organisms are commonly found in organic matter, including bedding and manure. Klebsiella spp. are naturally abundant on the forest floor, so their presence in sawdust is common. Therefore, cows bedded on fresh sawdust are at an increased risk for mastitis caused by Klebsiella spp. Loads of sawdust containing high counts of Klebsiella spp. have been linked to herd outbreaks of Klebsiella mastitis. Poor udder cleanliness, inadequate stall management, and damaged teat ends are risk factors for Klebsiella infections in uninfected cows.
How Do Klebsiella spp. Infect the Mammary Gland?
Klebsiella spp. will infect mammary glands through environmental contact. As with all environmental organisms, maintaining a clean and dry environment for bedding cows is of utmost importance. In particular, the use of inorganic bedding (sand) will reduce the environmental contamination with these bacteria. However, it is important to remember that recycled sand can still serve as a source of environmental contamination as organic matter accumulates in the bedding material.
How Can You Prevent and Control Mastitis Caused by Klebsiella spp.?
The control of Klebsiella spp. includes maintaining a clean and dry housing environment and implementing proper milking procedures. At milking time, all quarters should be forestripped, which will begin the milk letdown process.
After forestripping, the use of an efficacious and proven premilking teat disinfectant is particularly important for this mastitis-causing pathogen. The premilking teat disinfectant should remain on the teats for 30 seconds prior to removal with either a paper towel or a single-use clean and dry cloth towel. Following these guidelines, the time from start of manual stimulation (forestrip or wipe) to unit attachment should be in the range of 60 to 120 seconds. This will allow the appropriate time for milk letdown.
Following unit detachment, the application of an efficacious and proven postmilking teat disinfectant should be applied with coverage over at least two-thirds of the teat barrel. In herds with a particular environmental mastitis problem, the use of a barrier teat dip is recommended.
In addition, reducing teat end exposure between milkings by scraping the back of cow stalls (where the udder rests) and applying fresh bedding frequently is imperative. The application of bedding conditioners such as hydrated lime is effective at reducing the bacterial load in the bedding. However, the activity of these products is short-lived, making frequent application necessary. It is recommended that 2 pounds be applied per stall, and it must be applied every other day.
Another key control procedure for reducing Klebsiella spp. infections is to avoid the use of sawdust and recycled manure bedding. In situations where sawdust bedding must be used, the use of a kiln-dried product is suggested. This process essentially eliminates the Klebsiella spp. entering the farm from the forest floor and will help reduce the bacterial load in the clean product.
The use of a coliform mastitis vaccine (J5 bacterin) has been shown to reduce the severity of clinical Gram-negative mastitis, which includes Klebsiella spp. It is important to remember that these vaccines do not reduce the incidence of mastitis. Vaccination administration schedules and the appropriate number of doses have been researched. Talk with your veterinarian before implementing a vaccination protocol.
When Are Klebsiella Infections Most Likely to Occur?
New infections can occur at any time during lactation and may also occur during the dry period. However, cows in early lactation are at an increased risk for new infections due to the increased stress and immune suppression associated with the postpartum period.
Additionally, cows are also at an increased risk for mastitis immediately after drying-off. Following milk cessation, cows do not experience the daily flushing of the gland, which increases their risk. Cows with high milk production are not at greater risk than cows with low milk production.
How Likely Are Klebsiella Infections to Cure?
When Klebsiella bacteria die, a toxin is released; the toxin is the primary cause of the clinical signs observed in a local mastitis infection. Antibiotics act to kill bacteria and, in the case of these infections, would then result in the toxin release. Therefore, intramammary antibiotic treatment is not a generally recommended practice for local infections.
In some cases, Klebsiella infections can become systemic, in which case antibiotic treatment and supportive therapy are required. In recent years, there has been discussion regarding the presence of chronic infections caused by Klebsiella spp. However, a mechanism for these infections becoming chronic is not yet known.
As a reminder, veterinary consultation is recommended prior to the start of any treatment protocol. Due to the nature of these bacteria, emphasis needs to be placed on prevention of these infections rather than on their treatment.
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg.
July 29, 2011