J Arthropod-Borne Dis, September 2018, 12(3): 321–324 PG de Mendonça: Cross-Genera PCR …

Short Communication Cross-Genera PCR Amplification of DNA from Apicomplexan Parasites

*Philippe Gil de Mendonça

Institute of Comparative Tropical Medicine and Parasitology, Ludwig Maximilian University, Munich, Germany

(Received 11 Dec 2016; accepted 20 June 2018)

Abstract Background: The discovery of an unexpected genetic sequence raised doubts about the specificity of a primer pair targeting spp. and spp. This study aimed to check the specificity of this primer pair. Methods: Conventional end-point PCR and real-time PCR protocols using primers targeting the 18S rRNA gene V4 hypervariable region of Babesia spp. and Theileria spp. were tested for potential cross-genera amplification using DNA from a palette of parasitic protists and pathogenic bacteria as a template. These investigations took place at the Ludwig Maximilian University of Munich (Germany) in 2010 as part of the EDEN project. Results: Successful amplification was obtained with DNA from five apicomplexan genera: Babesia, Theileria, Hepa- tozoon, Toxoplasma, and Hammondia. No amplicons were obtained when DNA from Leishmania infantum or bacte- ria within the genera Borrelia, Leptospira or Anaplasma was used as a template. Conclusion: This cross-genera amplification ability is useful for the quick exclusion of many parasite species from PCR negative diagnostic samples. Accurate species identification from PCR positive samples requires genetic se- quencing of the amplicon.

Keywords: Babesia, Theileria, , Toxoplasma, Hammondia

Introduction

Babesia spp. and Theileria spp. are wide- species in GenBank, and identity values were spread tick-borne parasites. They are a cause relatively low). These results raised serious of concern to the medical and veterinary concerns about the specificity of the PCR pro- community worldwide (1-10). Several species tocol used for screening Babesia spp. and are even considered as an emerging threat to Theileria spp. human health (9-10). The EU-funded EDEN In order to check for the actual presence project focused specifically on investigating of further cases of cross-genera amplification, emerging diseases (11). Within this context, the tests described below were performed us- arthropod vectors and vertebrate hosts were ing template DNA from a variety of protists routinely sampled and screened for a large and other microorganisms. palette of zoonotic pathogens. A combination of techniques (12), namely PCR followed by Materials and Methods reverse-line blot (RLB), was routinely used for screening Babesia spp. and Theileria spp. On PCR was performed with DNA from ref- various occasions, the panel of RLB probes erence samples of parasitic protists as a tem- available was not suitable for the identifica- plate. Reference samples of parasitic protists tion of the parasite species involved. In such included: Babesia canis, B. capreoli, B. diver- cases, amplicons were sequenced. Sequencing gens, B. gibsoni, B. microti (syn. Theileria mi- revealed the presence of -like or- croti), B. rodhaini (syn. Theileria rodhaini), B. ganisms (sequences did not match any known vogeli, Hepatozoon sylvatici, Toxoplasma 321 * Corresponding author: Dr Philippe Gil de http://jad.tums.ac.ir Mendonça, E-mail: [email protected] Published Online: September 30, 2018

J Arthropod-Borne Dis, September 2018, 12(3): 321–324 PG de Mendonça: Cross-Genera PCR …

gondii, and Leishma- 2010 as part of the EDEN project. nia infantum. Sequencing of amplicons was performed by PCR was also performed with DNA from Eurofins MWG GmbH (Ebersberg, Germany). wildlife samples (arthropod vectors and ver- tebrate hosts) known to be positive for a pal- ette of bacterial pathogens. These bacterial Results pathogens included Borrelia afzelii, Leptospira interrogans and Anaplasma phagocytophilum. As expected, all Babesia spp. and Theileria Pure water was used as no-template control. spp. yielded amplicons with strong positive DNA was amplified using primers (F 5’- signals on both conventional and real-time GACACAGGGAGGTAGTGACAAG and R PCR, and their sequences were consistent with 5’-CTAAGAATTTCACCTCTGACAGT) tar- data available on GenBank, thus confirming geting the 18S rRNA gene V4 hypervariable successful and accurate PCR amplification of region of Babesia spp. and Theileria spp. (13). Babesia and Theileria reference samples. Real-time PCR with dissociation curve anal- Hepatozoon sylvatici, , ® and Hammondia hammondi also yielded am- ysis was performed with QuantiFast SYBR plicons with strong positive signals on both Green (QIAGEN, Hilden, Germany) follow- conventional and real-time PCR, and their se- ing the manufacturer’s instructions. quences were also consistent with data avail- Conventional end-point PCR followed a able on GenBank, thus also confirming suc- modified touch-down protocol (14). One cycle cessful and accurate PCR amplification of at 95 °C for 5min for Hot Start Taq activa- Hepatozoon, Toxoplasma and Hammondia ref- tion was followed by touch-down steps (de- erence samples. naturation at 94 °C for 20sec, annealing for No amplicon could be obtained from L. in- 30 sec starting at 67 °C and dropping to 57 fantum. No amplicon was obtained either from °C at a rate of 1 °C/step, extension at 72 °C any of the bacterial pathogens tested. for 30sec) prior to 40 amplification cycles Melting temperature values for the various (denaturation at 94 °C for 20sec, annealing species successfully amplified ranged from at 57 °C for 30sec, extension at 72 °C for 30 79.8 °C to 85.7 °C with overlap between vari- sec). Reaction mix composition was: 5.00μl ous species. Amplicon sizes ranged from 402bp 10x QIAGEN PCR buffer (at 15mM MgCl2), to 528bp with overlap between various species. 2.00μl QIAGEN MgCl2 (at 25mM), 1.00μl QI- AGEN dNTPs (10mM), 1.00μl of each primer (10μM), 29.75μl ultra-pure water, 0.25μl QI- Discussion AGEN Hot Start Taq Plus (5U/μl). Total vol- ume was 50μl, including 10μl template DNA. The of protists has undergone PCR products were separated by electropho- many revisions and has been revolutionized resis through 1.5% agarose gels stained with from top to bottom in the last few years (15, GelRed® (Biotium, Hayward, California). Size 16). The taxonomy of the species within the markers (reference DNA ladder) were included genus Babesia is no exception to this rule in each gel. Amplicons and size markers were (17, 18). However, for the sake of simplicity, visualized by UV transillumination. Amplicon a traditional approach was retained in the pre- sizes were estimated with GelAnalyzer 2010 sent article which is concerned with molecu- (www. gelanalyzer.com/download.html). lar diagnostic methodology, rather than taxo- These investigations took place at Ludwig nomic changes. Maximilian University, Munich, Germanyin The PCR primer pair used in the present

322 http://jad.tums.ac.ir Published Online: September 30, 2018

J Arthropod-Borne Dis, September 2018, 12(3): 321–324 PG de Mendonça: Cross-Genera PCR …

study was known for its ability to detect two plasma, and Hammondia. Genetic sequenc- closely related protist genera: Babesia and ing of the amplicons is required for accurate Theileria. The above-mentioned results re- species identification. vealed the ability to detect yet further protist genera, namely Hepatozoon and the closely related Toxoplasma and Hammondia. Acknowledgments All these genera belong to the , which suggests that the PCR primer pair used This study was partially funded by EU grant here might amplify even more genera within GOCE-2003-010284 EDEN. The contents of this . This unexpected widespread cross- this publication are the sole responsibility of genera amplification ability might seem prob- the author and do not necessarily reflect the lematic at first glance, however, this turns out views of the European Commission. to be a rather useful property when consid- Additional support was provided by the Ba- ered in a wider context. Indeed, screening with varian Ministry for Environment and Public this primer pair makes it possible to exclude Health (VICCI Project - Module 3). a large number of parasitic species at once It is a pleasure to thank (in non-preferen- for those samples yielding negative PCR re- tial alphabetical order) L Chaudhuri and C sults, thus avoiding expansive and time-con- Thiel who kindly made available reference suming further testing for the numerous spe- samples of Leishmania infantum, Babesia gib- cies within the genera known to be efficient- soni and B. vogeli. The author declares that ly amplified by this peculiar primer pair. As there is no conflict of interest. a corollary to this, it will be most useful to perform yet further testing of additional gen- era within the Apicomplexa in order to es- References tablish the full width of the palette of genera efficiently amplified and thus detected when 1. Aktas M, Altay K, Dumanli N (2005) De- screening samples with this primer pair. Ad- velopment of a polymerase chain re- ditional testing of protist genera outside the action method for diagnosis of Babe- Apicomplexa would also be desirable. sia ovis infection in sheep and goats. Most importantly, due to widespread over- Vet Parasitol. 133(4): 277–281. laps in amplicon sizes and melting tempera- 2. Bourdoiseau G (2006) Canine babesiosis tures on the one hand, and due to limitations in France. Vet Parasitol. 138(1– of the RLB technique on the other hand, ge- 2):118–125. netic sequencing of the amplicon is required 3. Chaudhry ZI, Suleman M, Younus M, Aslim for accurate species identification. A (2010) Molecular Detection of Babe- sia bigemina and Babesia bovis in Crossbred Carrier Cattle Through PCR. Conclusion Pakistan J Zool. 42(2): 201–204. 4. Esmaeilnejad B, Tavassoli M, Asri-Rezaei The range of detection of the primer pair S, Dalir-Naghadeh B, Mardani K, Go- targeting the 18S rRNA gene V4 hypervaria- labi M, Arjmand J, Kazemnia A, Jalil- ble region of Babesia spp. and Theileria spp. zadeh G (2015) Determination of prev- is not limited to these two closely related gen- alence and risk factors of infection with era. At least three additional apicomplexan Babesia ovis in small ruminants from genera are efficiently amplified by this pri- West Azerbaijan Province, Iran by pol- mer pair. These genera are Hepatozoon, Toxo- ymerase chain reaction. J Arthropod

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