Bacterial community composition of three candidate insect vectors of palm phytoplasma (Texas Phoenix Palm Decline and Lethal Yellowing).

Texas Phoenix Palm Decline (TPPD) and Lethal Yellowing are two phytoplasma-linked diseases in palms. The phytoplasma causing TPPD is thought to be transmitted by three putative planthopper vectors, Ormenaria rufifascia, Omolicna joi, and Haplaxius crudus. These insects have been morphologically and molecularly described, and have screened positive for Candidatus Phytoplasma palmae. Individuals from each species were subjected to 16S bacterial community sequencing using the Roche 454 platform, providing new information regarding the previously unexplored bacterial communities present in putative vectors.

Identification and location of symbionts associated with potato psyllid (Bactericera cockerelli) lifestages.

The potato psyllid (Bactericera cockerelli, Sulc) is an invasive pest of solenaceous plants including potatoes (Solanum tuberosum L.)and tomatoes (Solanum lycopersicum L.). The insect transmits the phytopathogen Candidatus Liberibacter solanacearum, which has been identified as the causal agent of Zebra Chip in potatoes. The microbiome of the potato psyllid provides knowledge of the insect's bacterial makeup which enables researchers to develop targeted biological control strategies. In this study, the microbes associated with four B. cockerelli life stages were evaluated by 16S bTEFAP pyrosequencing. The sequences were compared with a 16S-rDNA database derived from NCBI's GenBank. Some bacteria identified are initial discoveries. Species of Wolbachia, Rhizobium, Gordonia, Mycobacterium, Xanthomonas and others were also detected and an assessment of the microbiome associated with B. cockerelli was established.

Antimicrobial susceptibility of nontuberculous mycobacteria from eye infections.

PURPOSE: To characterize formerly designated atypical or nontuberculous mycobacteria (NTM) associated with eye infections. METHODS: All clinical NTM eye isolates (112 isolates from 100 patients) submitted to a single national NTM reference laboratory between 1982 and 2009 were identified using polymerase chain reaction and restriction fragment length polymorphism of the hsp65 gene. Isolates were tested against 10 antimicrobials, including besifloxacin, a new 8-chloro-fluoroquinolone. Assessments included species of NTM recovered, year of isolation, type of eye infection, geographic location, and drug susceptibilities. RESULTS: In the 1980s, the major pathogen isolated was Mycobacterium abscessus. In the 1990 s, Mycobacterium chelonae emerged as the major pathogen. By 2000, it was responsible for more than 50% of all cases. The majority of M. abscessus and Mycobacterium fortuitum were from southern coastal states and Texas, whereas M. chelonae isolates were more widespread geographically. The most active antimicrobials were amikacin and clarithromycin/azithromycin for M. abscessus and clarithromycin/azithromycin, amikacin, and tobramycin, and the quinolones for M. chelonae. CONCLUSIONS: This is the largest study of NTM ophthalmic isolates to date and is the first to include susceptibilities and molecular identification for all isolates studied. This series establishes M. chelonae (44%) and M. abscessus (37%) as the NTM species most frequently associated with ophthalmic infections. Topical ophthalmic fluoroquinolones may have a role in the management of ocular infections involving M. chelonae and M. fortuitum.

Culture independent survey of the microbiota of the glassy-winged sharpshooter (Homalodisca vitripennis) using 454 pyrosequencing.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), is an invasive pest that has spread across the southern and western United States. H. vitripennis is highly polyphagous and voracious, feeding on at least 100 plant species and consuming up to 100 times its weight in xylem fluid daily. The insect is a vector of the phytopathogen Xylella fastidiosa (Wells), which is the causative agent of Pierce's disease in grapevines. To evaluate the microbial flora associated with H. vitripennis, total DNA extracts from hemolymph, alimentary canal excretions, and whole insect bodies were subjected to 16S rDNA pyrosequencing using the bTEFAP methodology and the resulting sequences (370-520 bp in length) were compared with a curated high quality 16S database derived from GenBank http://www.ncbi.nlm.nih.gov. Species from the genera Wolbachia, Delftia (formerly Pseudomonas), Pectobacterium, Moraxella, Serratia, Bacillus, and many others were detected and a comprehensive picture of the microbiome associated with H. vitripennis was established. Some of the bacteria identified in this report are initial discoveries; providing a breadth of knowledge to the microbial flora of this insect pest can serve as a reservoir of information for developing biological control strategies.

Detection and analysis of the bacterium, Xylella fastidiosa, in glassy-winged sharpshooter, Homalodisca vitripennis, populations in Texas.

The glassy-winged sharpshooter, Homalodisca vitripeninis Germar (Hemiptera: Cicadellidae), is a xylophagous insect that is an endemic pest of several economically important plants in Texas. H. vitripennis is the main vector of Xylella fastidiosa Wells (Xanthomonadales: Xanthomonadaceae), the bacterium that causes Pierce's disease of grapevine and can travel long distances putting much of Texas grape production at risk. Understanding the movement of H. vitripennis populations capable of transmitting X. fastidiosa into Pierce's-disease-free areas is critical for developing a management program for Pierce's disease. To that end, the USDA-APHIS has developed a program to sample vineyards across Texas to monitor populations of H. vitripennis. From this sampling, H vitripennis collected during 2005 and 2006 over the months of May, June, and July from eight vineyards in different regions of Texas were recovered from yellow sticky traps and tested for the presence of X. fastidiosa. The foregut contents were vacuum extracted and analyzed using RT-PCR to determine the percentage of H. vitripennis within each population that harbor X. fastidiosa and have the potential to transmit this pathogen. H. vitripennis from vineyards known to have Pierce's disease routinely tested positive for the presence of X. fastidiosa. While almost all H. vitripennis collected from vineyards with no history of Pierce's disease tested negative for the presence of the pathogen, three individual insects tested positive. Furthermore, all three insects were determined, by DNA sequencing, to be carrying a strain of X. fastidiosa homologous to known Pierce's disease strains, signifying them as a risk factor for new X. fastidiosa infections.

Mycobacterium neoaurum and Mycobacterium bacteremicum sp. nov. as causes of mycobacteremia.

Reference isolates of Mycobacterium neoaurum, Mycobacterium aurum, and the nonvalidated species "Mycobacterium lacticola" were the focus of two recent molecular taxonomic studies. On the basis of this grouping, we identified 46 clinical pigmented, rapidly growing mycobacterial isolates. By 16S rRNA gene sequencing, only two major taxa were identified: M. neoaurum and a previously uncharacterized "M. neoaurum-like" group. The M. neoaurum-like group exhibited only 99.7% identity to M. neoaurum by 16S rRNA gene sequencing and 96.5% identity to M. neoaurum by rpoB sequencing and was named M. bacteremicum. No clinical isolates of M. aurum or M. lacticola were identified. Of isolates with known sources, 4/8 (50%) of M. bacteremicum isolates and 22/34 (65%) of M. neoaurum isolates were recovered from blood, and 35% of these were known to be from patients with catheter-related sepsis. MIC and clinical data on these 46 isolates of M. neoaurum and M. bacteremicum along with a review of 16 previously reported cases of infection with the M. neoaurum-M. lacticola group demonstrated that the isolates were highly susceptible to all drugs tested except clarithromycin, and most clinical cases were successfully treated. The clarithromycin resistance suggested the presence of an inducible erm gene reported in other species of rapidly growing mycobacteria. Sequencing studies are currently required to identify these two species. Strain ATCC 25791 (originally submitted as an example of Mycobacterium aurum) is proposed to be the type strain of M. bacteremicum.