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Paenibacillus associated with milky disease in Central and South American scarabs
H Harrison1, R Patel, A A Yousten
1Microbiology Section, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
Abstract:
Thirty-one isolates of bacteria causing milky disease in scarab larvae collected in Central and South America were identified as Paenibacillus popilliae or Paenibacillus lentimorbus by use of DNA similarity analysis. The isolates were more similar to each other than to the North American isolates that are the type strains of the species. All of the bacteria of both species produced parasporal bodies, a characteristic previously believed to be unique to P. popilliae. Screening of the bacteria using PCR with parasporal protein primers revealed differences among the parasporal protein genes of P. popilliae isolates and between the parasporal genes of P. popilliae and P. lentimorbus. In contrast to P. popilliae from North America, none of the isolates from Central and South America was resistant to vancomycin, an indication of an interesting geographic distribution of the resistance genes.
Insights
Newly identified Paenibacillus bacteria from Central and South America causing milky disease in scarab larvae show unique genetic traits. These findings highlight geographic variations in bacterial species and their resistance genes.
Area of Science:
- Microbiology
- Insect Pathology
- Molecular Biology
Background:
- Milky disease, caused by Paenibacillus bacteria, affects scarab larvae.
- Previous research suggested distinct characteristics for Paenibacillus popilliae and Paenibacillus lentimorbus, including parasporal body production and vancomycin resistance.
Purpose of the Study:
- To identify and characterize Paenibacillus isolates from Central and South America causing milky disease in scarab larvae.
- To compare these isolates with North American strains using molecular methods.
- To investigate the genetic basis of parasporal body production and vancomycin resistance.
Main Methods:
- DNA similarity analysis for bacterial identification.
- Polymerase Chain Reaction (PCR) with parasporal protein primers for genetic screening.
- Vancomycin resistance assays.
Main Results:
- Thirty-one isolates were identified as Paenibacillus popilliae or Paenibacillus lentimorbus.
- Isolates from Central and South America were genetically similar to each other but distinct from North American type strains.
- All isolates produced parasporal bodies, challenging previous assumptions.
- Parasporal protein genes showed variations among P. popilliae isolates and between the two species.
- No Central or South American isolates exhibited vancomycin resistance, unlike North American strains.
Conclusions:
- Paenibacillus popilliae and Paenibacillus lentimorbus from Central and South America represent a distinct genetic group.
- Parasporal body production is not unique to P. popilliae.
- Geographic distribution of vancomycin resistance genes in these Paenibacillus species is noteworthy.