New 2013 CAPA Honey Bee Diseases and Pests manual is now available!

The new CAPA (Canadian Association of Professional Apiculturists) Bee Diseases and Pests manual (3rd edition) for 2013, edited by Stephen Pernal and Heather Clay, is now available!

They have a great website, too, accessible by clicking this link or the image below.

Order your own copy of this 68 page, full color manual (for $10 +S&H at the time of this post) via the contact information in this link.

The Bee Kingdom Archive

The Bee Kingdom Archive link

Dear friends,

Finally, after two years of travel and research, I am ready to organize The Bee Kingdom Archive. Please consider giving a small donation. I'll be producing two editions of prints for those who give larger donations. Please visit the fundraising site at Hatchfund for details: http:www.hatchfund.org/project/the_bee_kingdom_archive

Thank you!

+++
Joy Garnett
Brooklyn, NY
http://joygarnett.com
+++

THE BEE KINGDOM ARCHIVE

Dr. Ahmed Zaky Abushady (1892-1955) was an influential Egyptian scientist, beekeeper, and poet. He was also my maternal grandfather. For the past two years I have been gathering and sorting the many documents that Abushady left behind. Taken together, these documents chart my grandfather's innovative beekeeping practices in early 20th century Egypt and England, as well as his development as a poet and thinker.
I am asking for your support so I can begin to organize this collection of historically valuable and visually compelling material into a searchable archive: The Bee Kingdom Archive. 
PROJECT DESCRIPTION
The Bee Kingdom Archive will include decades of correspondence between Abushady, his famly and his peers, diagrams and patents for beekeeping inventions, manuscripts, poetry, ephemera, Abushady's own scientific and literary publications, and books from his personal library. And because Abushady was drawn to new gadgets and inventions like the handheld Kodak camera, it will contain a large number of photographs and 'snaps' of his activities in the laboratory and in the apiary, many of which he shot himself.
Much of this material has never been published or shared before. It has been preserved for generations by various family members who strove to keep the family legacy intact through wars, displacements, and deaths.
It is my ultimate goal to find funding to digitize The Bee Kingdom Archive and make it accessible to historians, researchers, and artists. But first I must secure and organize the physical archive.

More information.

Please consider donating a dollar or more at Hatchfund.

...

Artist and writer Joy Garnett's work has long revolved around the archive as subject and medium. She will continue to develop The Bee Kingdom Archive as an open access, virtual museum for her post-doctoral work at Winchester School of Art at the University of Southampton (UK), in a program that emphasizes interdisciplinary research across the arts. She is also working on a book about her grandfather, Ahmed Zaky Abushady. In an August 2013 interview, she answered a few questions about Abushady, his work, and her book project:
AZ Abushady: Revolutionary Egyptian Poet, Feminist, Beekeeper, and More, Interview with Joy Garnett, by M. Lynx Qualey, for Arabic Literature (in English) blog, August 26, 2013

Australian bee dog, Bazz.

Australian reporter Clint Jasper put together a great story on another bee dog, Bazz, used to detect honey bee colonies infected by AFB (American foulbrood) bacteria.  It includes an audio interview with beekeeper/handler Josh Kennett discussing the challenge of developing the bee suit that Bazz wears while he's working in the bee yard to avoid stings as well as scent training Bazz, initiated by trainer Martin Dominick.  Martin Dominick also trained the springer spaniel Elroy for scenting AFB in Australia, mentioned in an earlier post.  Bazz is the second black labrador I've heard about employed for scenting AFB.  See an earlier post about the black lab, Clinker, from the U.S.

The article is accessible by clicking the link below.

Dog suits up for a day in the hives - ABC Rural (Australian Broadcasting Corporation)

Canadian province Alberta is at the forefront of honey production and bee research

The world's largest bee was spotted one fine June day in Felher, Alberta getting ready for the big honey flow.

In addition to housing the world's largest bee, Alberta is also the 5th largest honey producing region in the world at present, producing on average 30.5 million pounds each year (Alberta agriculture and rural development) primarily from wildflower, canola, clover, and alfalfa nectar.  Commercial beekeepers from the region supply pollination services to blueberries right next door in British Colombia and to canola crops in the southern part of the province.  Fairview, Alberta is home to an internationally recognized commercial beekeeping certificate program, offered by Grand Prairie Regional College that provides 11 months of education and paid work experience focused on training individuals for careers in the bee industry.  This program originally was offered from 1981 to 1999 and only recently resumed in 2012, currently instructed by Eric Stromgren.  Information on the course can be found via their link below.  

But wait!   There's more!  Albert is also home to Beaverlodge Research Farm and the Canadian National Bee Diagnostic Center (NBDC), a facility born in 2012 via collaborative efforts between Grand Prairie Regional College and the national Beaverlodge Research Farm.   This is, after all, the reason I'm bragging about Alberta on BeeBugs.  If you're a Canadian beekeeper and want to know what's bugging your bees, you can send a sample to the NBDC.  They offer a range of diagnostic services including ultrastructure of comb and brood as well as molecular diagnostics.  They operate out of a fantastic, modern research lab located on the Beaverlodge Research Farm.  offering microscopy and molecular diagnostic services to bee keepers interested to identify virus, bacteria, fungi and protozoa micro-parasites in their bees.   A link to their website is available by clicking their logo:  

So, if you're considering a trip to Canada, why not consider Alberta and go on a quest for current and historical bee-centric sights, eh?

Links:

GPRC Commercial Beekeeping Certificate Program

Canadian National Bee Diagnostic Center

Beaver Lodge Research Farm

Can you identify bee guts infected with Nosema?

Last week I needed to collect a fresh Nosema ceranae sample from a honey bee to use in an experiment.  We generally have a high prevalence of Nosema ceranae in the colonies here at the Bee Research Lab in Maryland, and a heavily infected individual is not too difficult to locate.  But, how do I tell if a bee is infected or not?  Some people say they can tell by looking at the midgut region of the bee's digestive tract whether or not they are infected by Nosema.  The midgut is the specific region of the honey bee gut that both species of Nosema (Nosema apis and Nosema ceranae) infect.

Do you think you can identify a Nosema infection by looking at the midgut?

Here's the test

• Adult workers were collected from an apparently healthy colony on July 3rd (that's right; no sign of dysentery, nosemosis, excessive bee poop on the porch, etc.) and brought to the lab.

• Bees were cold anesthetized on ice.

• Digestive tracts were then removed from 9 individual bees, shown below with both light (left) and dark (right) background.

Can you identify which of the 9 midguts shown are infected by Nosema ceranae?

 

Hints 

1.  At least one midgut shown is heavily infected with about 50 million Nosema spores.

2.  At least one midgut shown has no detectable Nosema spores.

Got your answer?  Give up???  Scroll down for the answers.

Here are light microscope images (400x) of the contents from each midgut shown above:

Only midgut #2 is infected with Nosema ceranae.  In some (#1, #4, #8, #9) large pollen grains are visible.  Some cellular debris (including what look to be lipid spheres) can be seen in the remaining images.  If you answered this correctly you were either a) lucky or b) know something I don't and were lucky.

What does this mean?

Gross examination of the midgut itself is not a reliable way to identify infected individuals.  I can never tell with any measure of confidence whether or not a midgut is infected, and I've looked at a lot of midguts!  It has been suggested that a field test can be used to diagnose Nosema infected midguts by visual inspection, looking for a light color and swelling.  This may be true for pure Nosema apis infections (with which I don't have experience), but is not true for the now most prevalent species N. ceranae and is also probably not true for mixed species infections.  As shown above, the lightest colored midguts (#5, #8, #9) were not infected and midguts equally large (#1, #7, #9) as the infected one (#2) were not infected.

How do I know this is Nosema ceranae?  

Because I extracted DNA from this sample and used a molecular diagnostic test called polymerase chain reaction (PCR) with empirically determined species-specific primers that can differentiate Nosema ceranae from Nosema apis. (See Table S1 below from R. Schwarz and J. Evans. 2013. Single and mixed-species trypanosome and microsporidia infections elicit distinct, ephemeral cellular and humoral immune responses in honey bees.  Developmental and Comparative Immunology 40, 300-310. http://dx.doi.org/10.1016/j.dci.2013.03.010 ).  Although N. ceranae spores are slightly smaller than N. apis, molecular diagnostics are the only way Nosema species identification can be reliably made in my opinion.

Illustrations from "Anatomy of the Honey Bee" by Robert E. Snodgrass

There are few detailed, high quality drawings of bee anatomy available.  Thanks to the University of Georgia Cooperative Extension for posting a digital copy of "The Anatomy of the Honey Bee" by Robert E. Snodgrass.  His anatomy drawings are some of the best made.  It's a difficult book to find in print, so the digital version is very helpful.

Images as well as a full digital version can be accessed via this link:

Illustrations from Anatomy of the Honey Bee by R.E. Snodgrass - eXtension

Since it's called a small hive beetle, does that mean there's a large hive beetle, too?!

Photo: Udo Schmidt, 2006; Oplostomus fuligineus Olivier, 1789;
Location: Senegal, M`Bour

I had the opportunity to speak with Queen Turner, a biologist with the Ministry of Agriculture beekeeping section in Botswana who is diligently working toward improving the health, management, and image of honey bees and beekeeping in her country.  Botswana is located in the southernmost region of Africa, just to the north of South Africa.  Honey bees in Botswana are maintained by small scale keepers primarily, who have just a few hives each.  Honey from the colonies is important as a food and revenue source for some areas but currently honey bees are not used commercially for improved agriculture pollination.  The Botswana Bee Importation Act of 1910 closed import and export of live honey bees from the country, but swarming colonies along border regions may ignore this law.  While the presence and distribution of microscopic pests (like viruses and bacteria) have yet to be determined, larger pests clearly occur.  These include Varroa destructor mites, wax moths, small hive beetle, and large hive beetle!  I doubt many beekeepers outside of Africa have even heard of a large hive beetle since they have not been introduced to other continents.  I certainly hadn't, so I did a bit of research on them.

Two species of large hive beetle

As it turns out, there are two species of large hive beetles: Oplostomus fuligineus (Olivier) and Oplostomus haroldi (Witte).  Both are specialized pests of honey bee colonies not unlike the small hive beetles Aethinia tumida, although they are not closely related.  Small hive beetle belong to the sap beetle family (Nitidulidae) while large hive beetles are a type of scarab beetle (Scarabaeidae).  Both appear to be strongly associated with honey bee colonies.

Morphology

A lateral and dorsal view of both a small hive beetle (SHB) and the large hive beetle (LHB) O. fuligineus collected from Australia and South Africa, respectively, by Simon Hinkley and Ken Walker are shown below.  The LHB are of course quite a bit larger than the SHB, with total body length of the LHB at around 20mm compared to the 6mm SHB.  O. fuligineus and O. haroldi are similar in appearance and difficult to distinguish from one another without close examination.

Small Hive Beetle (Aethinia thumida)

Small Hive Beetle (Aethinia thumida)

Large Hive Beetle (Oplostomus fuligineus)

Large Hive Beetle (Oplostomus fuligineus)
(All above images: Creative Commons Attribution 3.0 Australian License by Ken Walker)

Distribution

Large hive beetles have been documented pests of managed bee hives in South Africa since the early 1900's, though they have likely associated with honey bees on the continent for much longer.  Both species of LHB currently are documented only from Africa including Botswana, Kenya, Namibia, Nigeria, Senegal, South Africa, Tanzania and Zimbabwe.  There is evidence that O. haroldi is more frequent in coastal areas vs. inland areas so local environmental conditions may affect their prevalence.

Impact on honey bee colonies

Although SHB are more prevalent in honey bee colonies in Africa, LHB are generally considered more serious and destructive pests when they occur.  Adult LHB occur more frequently on frames rather than bottom boards, where they consume uncapped and capped brood as well as pollen and honey stores.  Since they are about as big as a honey bee, it's probably much more difficult for bees to deter them off of the frames but bees will attack by biting at them.  Ms. Turner said bees will also cover these beetles in propolis occasionally.  Probably most importantly, the presence of LHB may cause honey bee colonies to abscond (abandon) from the hive.  They may reach peak numbers of 6 to 20 per frame for O. fuligineus and O. haroldi, respectively.  Unlike SHB, larvae of both LHB species do not seem to occur in the honey bee colony and typically live and pupate in decomposing plant matter or dung of cows or donkeys.

The spread of hive beetles

Neither species of LHB have been documented outside of Africa that I have found.  Unfortunately, the SHB has been introduced to North America (mid 1990's) and Australia (early 2000's).  The first official documentation of SHB in North America was from Florida in 1998 likely via a shipment of honey bees from South Africa, where the SHB is native.  A similar accidental introduction of LHB to other continents is theoretically possible if bees or contaminated comb were to be imported.  Given the large size of these beetles, they would readily be noticed during routine opening and examining of a hive.

 

References
Biodiversity occurrence data published by: Lund Museum of Zoology - Insect collections (MZLU) (Accessed through GBIF Data Portal, data.gbif.org, 2012-05-08).

Donaldson, J.M.I. 1989. Oplostomus fuligineus (Coleoptera: Scarabaeidae): Life cycle and biology under laboratory conditions, and its occurrence in bee hives. The Coleopterists Bulletin 43(2):177-182.

Fombong A.T., Haas F., Ndegwa P.N., and Irungu L.W. 2012. Life history of Oplostomus haroldi (Coleoptera: Scarabaeidae) under laboratory conditions and a description of its third instar larva. Int. J. Trop. Ins. Sci. 32(1):56-63.

Fombong A.T., Mumoki F.N., Muli E., Masiga D.K., Arbogast R.T., Teal P.E.A., and Torto B. 2013. Occurrence, diversity and pattern of damage of Oplostomus species (Coleoptera: Scarabaeidae), honey bee pests in Kenya. Apidologie 44:11-20.

Njau M.A., Mpuya P.M., and Mturi F.A. 2009. Apiculture potential in protected areas: the case study of Udzungwa Mountains National Park, Tanzania. Int. J. Biodiv. Sci. Management 5:95-101.

Oyerinde A.A. and Ande A.T. 2009. Distribution and impact of of honeybee pests on colony development in Kwara State, Nigeria. J. Agric. Soc. Sci. 5:85-88.

Torto B., Fombong A.T., Mutyambai D.M., Muli E., Arbogast R.T., and Teal P.E.A. 2010. Aethina tumida (Coleoptera: Nitidulidae) and Oplostomus haroldi (Coleoptera: Scarabaeidae): Occurrence in Kenya, distribution within honey bee colonies, and responses to host odors. Ann. Entomol. Soc. Am. 103(3): 389-396.

Comparative genome analysis of two Spiroplasma melliferum isolates

Figure 4 from Lo et al., 2013.  (Open Access)

About 1 year following the publication of a genome assembly for Spiroplasma melliferum KC3 by Dmitry Alexeev and colleagues comes an assembly from S. melliferum isolate IPMB4A by Wen-Sui Lo and colleagues. 

The papers:

Alexeev et al., 2012. Application of Spiroplasma melliferum proteogenomic profiling for the discovery of virulence factors and pathogenicity mechanisms in host-associated sprioplasmas. J. Proteome Res. 11(1), pp224-236.

 Wen-Sui Lo, L. Chen, W. Chung, G. Gasparich and C. Kuo. 2013. Comparative genome analysis of Spiroplasma melliferum IPMB4A, a honeybee-associated bacterium. BMC Genomics, 14:22.

Elroy the Bee Dog

Another Bee Dog to introduce!

This is Elroy, a springer spaniel trained by Martin Dominick in Australia to sniff out honey bee hives with American Foulbrood (AFB) disease.

Image from the Australian Government RIRDC.

Like Klinker the black lab from the Maryland Dept. of Agriculture, mentioned in an earlier post, Elroy is employed to seek out any honey bee colony that is infected with the AFB bacteria Paenibacillus larvae.  These bee dogs are able to do this work much faster and arguably more effectively than bee keepers (no offense intended to bee keepers).  Elroy even had a bee suit made especially for him so he could work at anytime and not worry about stings.  That's pretty darn cute.

Images of the article written about Elroy back in 2011 by the Australian Government Rural Industries Research and Development Corporation:

Taxonomic description of a Betaproteobacteria and a Gammaproteobacteria-1 from the honey bee gut

Nancy Moran's lab has worked with these two honey bee gut bugs previously, producing several prior publications.  A recent paper in the International Journal of Systemic and Evolutionary Microbiology by Waldan Kwong and Nancy Moran is important, however, as it provides the official and exhaustive work necessary to formally denominate these two new species.  It's also cool because they came up with some fun and worthy names for them!

The Beta, Snodgrassella alvi, is named after the American entomologist Robert Evans Snodgrass (1875-1962) whose numerous authorships include "The Anatomy of the Honeybee".  The specific epithet, alvi, is Latin for 'gut of bees'.  S. alvi was isolated not only from honey bees (Apis mellifera) but also from bumblebees (Bombus bimaculatus and Bombus vagrans).

The Gamma-1, Gilliamella apicola, is named in honor of the American microbiologist Martha A. Gilliam, who has worked extensively with the honey bee microbiota with interest in how these microbes can protect bees from harmful pathogens.  'Bee-dweller' is the translated Latin for the specific epithet apicola.  G. apicola was isolated not only from honey bees (Apis mellifera) but also from bumblebees (Bombus bimaculatus and Bombus vagrans).  In addition, Kwong and Moran determined that G. apicola-like bacteria also occur in a number of other bee species by analyzing previously identified bacteria sequences isolated from the Asian and giant honey bees (Apis cerana and Apis dorsata) and additional bumblebees (Bombus terrestris and Bombus impatiens).  As if describing the type species for this new genus wasn't enough, G. apicola belongs to a new Order (Orbales) and Family (Orbaceae), also described here by Kwong and Moran!

There is substantial genetic diversity in these groups, with isolates from the same bee host species more closely related to one another than to similar bacteria from other bee species.  This may be due to a close evolutionary history between bee host and their specific bacteria strain.  Thus, distinct Gilliamella and Snodgrassella species are likely to be discerned in future research.  

A link to the article published in the International Journal of Systemic and Evolutionary Microbiology is here:  Kwong and Moran, 2012

Cultivation and characterization of the gut symbionts of honey bees and bumble bees: Snodgrassella alvi gen. nov., sp. nov., a member of the Neisseriaceae family of the Betaproteobacteria; and Gilliamella apicola gen. nov., sp. nov., a member of Orbaceae fam. nov., Orbales ord. nov., a sister taxon to the Enterobacteriales order of the Gammaproteobacteria

1. Waldan K. Kwong and
2. Nancy A. Moran

1. Yale University

Dogs sniff out pathogenic bacteria in honey bee colonies

I'm a big fan of canines, and here is my favorite example of how to look for bee bugs.  This is William Troup and Klinker, working for the Maryland Department of Agriculture inspecting honey bee colonies.  Klinker, a black lab, was scent trained on American foul brood (AFB; Paenibacillus larvae), a pathogenic bacteria of European honey bee larvae that create a very distinct smell when present.

Picture from the Maryland Dept. of Agriculture

Once scent trained, dogs can be used to quickly assess colonies for any scent of the bacteria.  Having such a sensitive sense of smell, dogs can detect AFB even at low levels.  This prevents cracking open a hive and pulling out frames one by one to assess them for signs of AFB, particularly beneficial in early Spring when it still may be quite cold out and the girls need to keep in warmth for the developing brood.

If anyone knows of additional dog nose work training in other states/countries to detect pathogens or has updates on Klinker and William Troup at the MDA, please share the knowledge and post a comment.  I'd love to learn more about this.

A link to the MDA Apiary Inspection site is here:  http://mda2.maryland.gov/plants-pests/Pages/apiary_inspection.aspx

The genome of Paenibacillus alvei

Researchers from Georg-August University Göttingen Germany have completed the genomic sequence of P. alvei isolate DSM 29 (6.83Mb)  This is an aerobic, Gram-positive bacteria that is often associated with Melissococcus plutonius, the bacterial causative agent of European foul brood disease in honey bees.

Paenibacillus alvei are the larger, elongated bacteria.  Melissococcus plutonius bacteria are clustered in the center.  Photo from the USDA/ARS.

Along with P. alvei, a number of other bacteria also seem to associate frequently with M. plutonius infections including Brevibacillus laterosporus and Enterococcus faecalis.  Of note from the genome are a number of chitinase genes (10) and a hyaluronate lyase homolog, each of which may be virulence factors involved in host cell invasion.  Also, a unique antimicrobial gene and several encoded toxin molecules (binary, mosquitocidal, alveolysin, insecticidal toxin complex) were identified.  454 GS-FLX with Titanium XL was used to sequence paired-end and shotgun DNA libraries, assembled to 18x coverage in 25 contigs.  The genome contains approximately 6,605 coding genes.

A link to the paper in the Journal of Bacteriology is here:
P. alvei genome by Djukic, Becker, Poehlein, Voget, and Daniel

American Bee Research Conference 2013

The annual American Bee Research Conference is a honey bee-centric meeting of bee keepers and researchers being held this week in Hershey, Pennsylvania alongside the somewhat more popular North American Beekeeping Conference.  Bee bug topics are on schedule to be presented, and are linked here:

https://docs.google.com/file/d/0B4dGydUTgVgRZVc5S1AzZUVnUTg/edit


Pollen mites

While not of concern to honey bees, pollen mite (Chaetodactyllus) infestations can be of concern to other bee species, particularly blue orchard bees (Osmia lignaria) and other Osmia species (mason bees, Japanese hornfaced bee, etc.) of the family Megachilidae.  The Krombein's hairy-footed mite (Chaetodactyllus krombeini) is a pollen mite native to North America.  Additional species of Chaetodactyllus occur on other parts of the globe, more commonly in humid rather than arid regions.

When they infest brood cells, they will kill and then feed on bee eggs and larvae.  They will also feed on pollen stores, hence the common name.  Reproduction in the cell can produce a shocking mass of mites: 

USDA/ARS image of C. krombeini mites in a blue orchard bee brood cell.

Emerging adult bees from other cells in the nest can become covered with the mites, and give them a lift to new frontiers.  Some mites may also stay behind in the nest and parasitize a new female bee looking into using the abandoned nest.

Here is a link to a good description of the pollen mite, Chaetodactylus krombeini, from the North American Bee Mite Project at the University of Michigan: Species_Accounts/Chaetodactylus_krombeini.htm.  The second image is from the USDA/ARS.

A recent paper "Distribution of Chaetodactyllus krombeini (Acari: Chaetodactylidae) within Osmia cornifrons (Hymenoptera: Megachilidae) nests: implications for population management" by Matthew McKinney and Yong-Lak Park is here:  http://link.springer.com/article/10.1007/s10493-012-9629-7

Abstract

Chaetodactylus krombeini (Baker) (Acari: Chaetodactylidae) is a cleptoparasitic mite that negatively affects propagation of Osmia spp. (Hymenoptera: Megachilidae) for orchard pollination in the USA. This study was conducted to determine the effect of C. krombeini on mortality of male and female Osmia cornifrons, the Japanese hornfaced bee. A total of 107 O. cornifrons nests were examined to determine within-nest distribution of C. krombeini with regression analyses. A total of 30 mite-free O. cornifrons nests were observed and within-nest distribution of male and female O. cornifrons was determined with non-linear regression analyses. In addition, cocoons from 20 mite-infested O. cornifrons cells were examined to determine whether C. krombeini could be found inside cocoons of O. cornifrons. The results of this study showed that female O. cornifrons and C. krombeini were found more frequently in the inner part of the nest, and male O. cornifrons were found mostly in the center of the nest. No C. krombeini were found inside O. cornifrons cocoons. These results indicate that C. krombeini have a greater negative impact on mortality in the egg and larval stages of female O. cornifrons than in male O. cornifrons. Implications for management of C. krombeini and O. cornifrons populations for orchard pollination are discussed in this article.

The spread of antibiotic resistance genes due to pressure asserted by prolific antibiotic exposure in animals, in this case honey bees.

Antibiotics (oxytetracycline in this case) affect not only targeted pathogens like foul brood bacteria (Paenibacillus and Melissococcus) but also non-targeted endosymbiotic gut flora.  The latest from Nancy Moran's lab.  :

Long-Term Exposure to Antibiotics Has Caused Accumulation of Resistance Determinants in the Gut Microbiota of Honeybees

1. Baoyu Tian^a*, 
2. Nibal H. Fadhil^a, 
3. J. Elijah Powell^a, 
4. Waldan K. Kwong^a, and
5. Nancy A. Moran

http://mbio.asm.org/content/3/6/e00377-12

ABSTRACT

Antibiotic treatment can impact nontarget microbes, enriching the pool of resistance genes available to pathogens and altering community profiles of microbes beneficial to hosts. The gut microbiota of adult honeybees, a distinctive community dominated by eight bacterial species, provides an opportunity to examine evolutionary responses to long-term treatment with a single antibiotic. For decades, American beekeepers have routinely treated colonies with oxytetracycline for control of larval pathogens. Using a functional metagenomic screen of bacteria from Maryland bees, we detected a high incidence of tetracycline/oxytetracycline resistance. This resistance is attributable to known resistance loci for which nucleotide sequences and flanking mobility genes were nearly identical to those from human pathogens and from bacteria associated with farm animals. Surveys using diagnostic PCR and sequencing revealed that gut bacteria of honeybees from diverse localities in the United States harbor eight tetracycline resistance loci, including efflux pump genes (tetB, tetC, tetD, tetH,tetL, and tetY) and ribosome protection genes (tetM and tetW), often at high frequencies. Isolates of gut bacteria from Connecticut bees display high levels of tetracycline resistance. Resistance genes were ubiquitous in American samples, though rare in colonies unexposed for 25 years. In contrast, only three resistance loci, at low frequencies, occurred in samples from countries not using antibiotics in beekeeping and samples from wild bumblebees. Thus, long-term antibiotic treatment has caused the bee gut microbiota to accumulate resistance genes, drawn from a widespread pool of highly mobile loci characterized from pathogens and agricultural sites.

IMPORTANCE We found that 50 years of using antibiotics in beekeeping in the United States has resulted in extensive tetracycline resistance in the gut microbiota. These bacteria, which form a distinctive community present in healthy honeybees worldwide, may function in protecting bees from disease and in providing nutrition. In countries that do not use antibiotics in beekeeping, bee gut bacteria contained far fewer resistance genes. The tetracycline resistance that we observed in American samples reflects the capture of mobile resistance genes closely related to those known from human pathogens and agricultural sites. Thus, long-term treatment to control a specific pathogen resulted in the accumulation of a stockpile of resistance capabilities in the microbiota of a healthy gut. This stockpile can, in turn, provide a source of resistance genes for pathogens themselves. The use of novel antibiotics in beekeeping may disrupt bee health, adding to the threats faced by these pollinators.

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