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Systematic and Applied Microbiology 30 (2007) 221–228 www.elsevier.de/syapm
‘Candidatus Rhabdochlamydia crassificans’, an intracellular bacterial pathogen of the cockroach Blatta orientalis (Insecta: Blattodea) Daniele Corsaroa, Vincent Thomasb, Genevieve Goyb, Danielle Vendittic, Renate Radekd, Gilbert Greubb, a
CHLAREAS Chlamydia Research Association, 12 rue du Maconnais, 54500 Vandoeuvre-les-Nancy, France Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, 1011 Lausanne, Switzerland c Tredi Research Department, Faculty of Medecine, 9 avenue de la Foret de Haye, B.P. 184, 54505 Vandceuvre-les-Nancy, France d Institute of Zoology, Free University of Berlin, 14195 Berlin, Germany b
Received 29 December 2005
Abstract The genus Rickettsiella comprises various intracellular bacterial pathogens of arthropods, exhibiting a chlamydialike developmental cycle. Species may be divided into two main groups, the R. popilliae–R. grylli group and the R. chironomi group. Previous phylogenetic studies based on the 16S ribosomal RNA encoding gene showed that two Rickettsiella species, one from each group, belong in reality to two distantly related lineages, the g-Proteobacteria (R. grylli) and the Chlamydiales (‘Candidatus Rhabdochlamydia porcellionis’, a pathogen of terrestrial isopods). In the present work, the 16S rDNA sequence of another Rickettsiella-like species, causing abdominal swelling to its cockroach host Blatta orientalis, was determined and phylogenetic analysis performed. Identical 16S rDNA sequences of 1495 nucleotides were obtained from fat body and ovary tissues of both healthy and diseased cockroach individuals. The sequence shared only 73% of similarity with R. grylli, but 82–87% with most Chlamydiales, and even 96.3% with ‘Candidatus Rhabdochlamydia porcellionis’. Phylogenetic analyses confirmed the affiliation of the cockroach pathogen within the order Chlamydiales, and based on ultrastructural characteristics and genetic analyses, we propose its inclusion in the ‘Candidatus Rhabdochlamydia’ as a distinct taxon, ‘Candidatus Rhabdochlamydia crassificans’. These results extend our knowledge of the phylogenetic diversity of the Chlamydiales. r 2006 Elsevier GmbH. All rights reserved. Keywords: Rhabdochlamydia; Rickettsiella; Arthropods; Chlamydiales; Chlamydia-like organisms; Blatta orientalis; Endosymbiont
Introduction Domestic cockroaches (Insecta: Blattodea) include anthropophilic species living in food storage areas, Corresponding author. Tel.: +41 21 314 49 79; fax: +41 21 314 40 60. E-mail address:
[email protected] (G. Greub).
0723-2020/$ - see front matter r 2006 Elsevier GmbH. All rights reserved. doi:10.1016/j.syapm.2006.06.001
kitchens, and cellars where they find the appropriate food, humidity and temperature necessary to sustain their survival. Often associated with unsanitary conditions, cockroaches can act as reservoir and mechanical vectors of fungi, protozoans, worms and bacteria. They may contaminate foods and food storage devices, especially by their excreta that potentially contain pathogenic microorganisms. Antibiotic-resistant bacterial strains
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have been found in several cockroach species, especially in those living in hospitals [14,32]. In addition, different pathogens such as verotoxigenic Escherichia coli [40], Pseudomonas aeruginosa [13], Helicobacter pylori [23], and Mycobacterium avium [12] have been grown from feces of experimentally infected cockroaches up to several days after infection. The established role of cockroaches as reservoir and mechanical vectors of pathogens suggests that these animals may also represent a source of infection by novel emerging pathogens. Chlamydiales constitute a distinct bacterial lineage of obligate intracellular parasites that infect humans, mammals, birds, reptiles, amphibians and fishes, as well as some arthropods and various free-living amoebae [2,3,5,7,15,18,25,28,29, 35,36]. Molecular studies conducted on both clinical and environmental samples indicate a large genetic diversity within the group [4,21,27]. In addition, various invertebrates like cnidarians, bivalve molluscs and arthropods are known to be infected by intracellular parasites that resemble chlamydiae. Since molecular phylogenetic analyses have not yet been conducted, these are called by the trivial name of chlamydia-like organisms. Such a resemblance is based mainly on evidence of a putative developmental cycle exhibiting a small infectious stage, the Elementary Body, that matures intracellularly into a larger vegetative stage, the Reticulate Body, which multiplies by binary fission within an intravacuolar inclusion. Then, the Reticulate Body reorganizes into an intermediate, or condensing body, and finally into a new generation of Elementary Body which is released by the cell. However, since other intracellular bacteria like Coxiella [39] and Rickettsiella [38] seem to have convergently evolved similar developmental cycles, it is no longer sufficient to assign a bacterial strain to the Chlamydiales based only on these morphological traits. Rickettsiella species are arthropod
pathogens that can be separated into two main groups, the R. popilliae–R. grylli group and the R. chironomi group. Phylogenetic analyses based on the 16S rDNA have shown that Coxiella and R. grylli are closely related, and emerge within the g-Proteobacteria [34]. No phylogenetic analyses have been performed on the other Rickettsiella species, but genomic studies suggest that this genus contains an heterogeneous group of unrelated organisms [16,17]. Previously, Radek [33] described an intracellular pathogen of the Oriental cockroach Blatta orientalis, that infects mainly the fat body and causes a swelling of the abdomen in the late stage of infection. Electron micrographic studies have allowed to describe a developmental cycle which is similar, but not identical to the one of Rickettsiella chironomi [11], and the name of R. crassificans has been proposed for this strain [33]. A peculiar ultrastructure characterizes the rod-like, flat Elementary Body, which exhibits a cell wall of five layers, which is constituted by the plasma cell membrane, and in alternance by two electron-lucent and two electron-dense layers. In addition, one to two translucent oblong lamellae are present in the cytoplasm [33] (Fig. 1). Elementary bodies with a five-layered cell wall have been previously hypothethized for scorpion and spider pathogens, previously designed as Porochlamydia [30,31], and later renamed R. chironomi [38]. More recently, such a cell wall structure and translucent lamellae have been described for another Rickettsiella species infecting the hepatopancreas of Porcellio scaber (Crustacea: Isopoda) [8]. The determination of the 16S rDNA sequence of this isopod bacterium has allowed to recognize a novel lineage within the Chlamydiales, named ‘Candidatus Rhabdochlamydia porcellionis’ [25]. The category ‘Candidatus’ allows to accomodates newly recognized but yet uncultured bacterial taxa. Given the ultrastructural similarity between ‘Candidatus
Fig. 1. Ultrastructure of Candidatus Rhabdochlamydia crassificans. (a) Typical flat, rod-shaped elementary bodies, characterized by a five-layered cell wall (arrow head) and one or two oblong translucent lamellae (arrow) into the cytoplasm. Scale-bar 0.1 mm. (b) Inclusion showing elementary bodies (EB), reticulate bodies (RB), and some reticulate bodies undergoing cell division (arrow). Scale-bar 1 mm.
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Rhabdochlamydia porcellionis’ and the bacterial parasite of B. orientalis, we hypothesized that the cockroach Rickettsiella is of Chlamydial origin. This hypothesis was also supported by the increasing diversity within the Chlamydiales that include several potential emerging pathogens [4,5]. We report herein results of 16S rDNA sequencing and phylogenetic analysis of Rickettsiella crassificans infecting B. orientalis. Our work demonstrates that this bacterium is closely related to the novel chlamydial lineage ‘Candidatus Rhabdochlamydia porcellionis’, representing a distinct species. Thus, we propose the name ‘Candidatus Rhabdochlamydia crassificans’.
Materials and methods Animals A colony of the Oriental cockroach B. orientalis was obtained from the Federal Health Institute of Berlin, Germany. Laboratory maintenance conditions and electron microscopy were previously described by Radek [33]. Five adult cockroaches were studied, including three females and two males. One female exhibited an abdominal swelling whereas the four other cockroaches were apparently healthy. Fat bodies and, for the females, ovaries, were removed aseptically and frozen until DNA extraction.
DNA extraction and PCR Genomic DNA was extracted using the Aquapure Genomic DNA Tissue Isolation Kit (BioRad Laboratories, Hercules, CA, USA), following the manufacturer’s instructions. In order to specifically amplify the Chlamydiales 16S rRNA, we used the Chlamydiales specific primer 16SigF previously described by Everett et al. [9] with the primer RP2Chlam (50 -CTACCTTGTTACGACTTCAT-30 ) modified from Weisburg et al. [37]. Conditions for 16S rRNA gene amplification were 5 min at 94 1C, followed by 35 cycles of 1 min at 94 1C, 1 min at 51 1C, and 1 min 30 s at 72 1C. Manipulations were performed according to recommended guidelines and included negative controls starting from the DNA extraction step. Then, all successfully amplified PCR products were compared by sequencing the 298 bp hypervariable 16S rDNA signature region with primers 16SigF and 16SigR [9], allowing the selection of PCR products for complete sequencing of 1495 bp using 16SigF, RP2Chlam and the universal internal primers described by Adekambi and Drancourt [1].
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Phylogenetic analyses Sequences were edited by removal of the longer 50 and 3 ends so that their lengths matched that of the shortest sequence (1262 bp). Genetic and phylogenetic analyses were conducted by using MEGA version 2.1 [26]. Genetic distances were calculated using the pairwise deletion option of the MEGA software. The neighbourjoining, minimum evolution and parsimony methods were applied to infer trees using the p distance. The 16S rDNA gene sequence similarity with ‘Candidatus Rhabdochlamydia porcellionis’ was also determined by using the CLUSTWAL W program supported by the NPS website (http://npsa-pbil.ibcp.fr/). 0
Results A 1495 bp 16S rDNA fragment was successfully amplified with primers 16SigF and RP2Chlam from all the tested samples, i.e. five fat bodies and three ovaries of cockroaches with or without apparent signs of infection. Using the 16SigF and SigR primers, a unique 298 bp sequence was obtained from all samples. This sequence best BLASTed with the 16S rDNA sequence of ‘Candidatus Rhabdochlamydia porcellionis’ (GenBank acc. no. AY223862) with an e-value of 10134. The complete 1495-bp DNA fragment was then sequenced from fat bodies of a cockroach without signs of infection and of the Oriental cockroach with abdominal swelling (both females). Both 1495 bp sequences were identical and the nucleotide sequence was deposited in GeneBank (accession number AY928092). This 1495-bp fragment shared only 73% similarity with R. grylli and was thus clearly not affiliated with this species. Further genetic analysis demonstrated its affiliation with the order Chlamydiales. Indeed, it shared 87–86% sequence similarity with Parachlamydia and Neochlamydia species (family Parachlamydiaceae), 85–86% with Simkania species, ‘Candidatus Fritschea eriococci’, and ‘Candidatus Fritschea bemisiae’ (family Simkaniaceae), 82–85% with Waddlia species (family Waddliaceae), 82–83% with Chlamydia and Chlamydophila species (family Chlamydiaceae), and 80% with ‘Candidatus Piscichlamydia salmonis’ (Table 1). The closest species was ‘Candidatus Rhabdochlamydia porcellionis’. It exhibited as much as 97.1% similarity when considering only point mutations (Table 1) and 96.3% sequence similarity when taking also into account insertions and deletions. All phylogenetic analyses confirmed that the bacterial parasite of B. orientalis belongs to the order Chlamydiales and that it clusters with the recently described ‘Candidatus Rhabdochlamydia porcellionis’. Thus, bootstrap values of 100% in all treeing methods used
a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1
2
% Similaritya 3
4
5
6
7
8
9
10
11
12
13
14
15
The number at the top of each column corresponds to the species number as defined for each row.
Candidatus Rhabdochlamydia crassificans 100.0 Candidatus Rhabdochlamydia porcellionis 97.1 100.0 Candidatus Fritschea bemisiae 86.0 86.2 100.0 Candidatus Fritschea eriococci 86.2 85.9 96.9 100.0 Simkania negevensis 85.7 86.2 90.9 90.7 100.0 Parachlamydia acanthamoebae Bn9 87.4 87.6 86.6 87.3 87.7 100.0 Candidatus Protochlamydia amoebophila UWE25 86.0 85.6 85.1 85.7 85.4 92.8 100.0 Neochlamydia hartmannellae 85.9 85.4 85.9 85.2 85.6 91.1 91.0 100.0 Waddlia malaysiensis 85.2 85.2 84.9 85.8 86.1 90.5 90.4 88.8 100.0 Waddlia chondrophila 82.5 82.6 83.3 84.2 83.9 87.4 88.3 86.9 94.5 100.0 Chlamydophila abortus 83.4 83.2 83.7 83.7 81.8 85.6 85.8 86.5 86.3 84.5 100.0 Chlamydophila psittaci 83.5 83.2 83.7 83.7 82.0 85.9 85.9 86.7 86.4 84.6 99.6 100.0 Chlamydophila pneumoniae 83.4 83.0 84.7 84.3 82.1 86.6 86.6 86.0 86.2 84.7 95.6 96.0 100.0 Chlamydia trachomatis 82.6 82.6 83.7 83.6 82.6 85.0 85.0 86.1 85.9 84.7 94.4 94.5 93.3 100.0 Candidatus Piscichlamydia salmonis 80.5 80.9 81.5 81.5 81.0 81.9 81.8 81.4 82.2 81.5 81.5 81.7 82.0 80.9 100.0
Species no. Species
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Table 1. Comparison of 16S rDNA sequence similarities of Candidatus R. crassificans with those of representing species of the order Chlamydiales, showing its relatedness with Candidatus R. porcellionis
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100
U68 AY1 460 409 Sim 10 C 409 kani 11 C and a ne idat and g e ve us F idat nsis r us F ritsc itschea b em hea i erio cocc siae A Y4 i 6224 4 Ca ndid atus Pisc ichla myd ia sa lmon is AY1
Fig. 2. Unrooted phylogenetic tree showing the relationship of Candidatus Rhabdochlamydia crassificans with other members of the order Chlamydiales. The tree was inferred by using the neighbor-joining method (p-distance), based on the nearly complete sequence (1262 nucleotides) of the 16S rRNA gene. Bootstrap values resulting from 100 replications are presented at the branch points.
(Fig. 2). Thus, bootstrap values of 99%, 86%, and 86% in the neighbor-joining, minimum evolution and parsimony trees, respectively, supported the fork separating these two microorganisms from their closest relatives, the members of the Simkaniaceae family (Fig. 2).
Discussion Here, we demonstrate that R. crassificans is unrelated to R. grylli and clusters with ‘Candidatus Rhabdochlamydia porcellionis’ within the order Chlamydiales. The decision to test for the presence of chlamydial DNA originated from the evidence of strict ultrastructural similarities between the cockroach and the woodlouse pathogens, as deduced from the published microphoto-
graphs in the works of Radek [33] and Drobne et al. [8], respectively, and the successive phylogenetic identification of the woodlouse pathogen as a new lineage of Chlamydiales, ‘Candidatus Rhabdochlamydia porcellionis’ [25]. The hypothesis that the cockroach pathogen could be a member of the ‘Candidatus Rhabdochlamydia’ lineage was confirmed by both genetic and phylogenetic analysis of the 16S rRNA encoding gene (Fig. 2). As stated by Everett et al. [9], chlamydial strains showing more than 95%, but less than 98.5% rDNA sequence identity, should be placed into the same genus as distinct species. Such cut-offs have been used by Thao et al. [36] to separate two closely related strains of homopteran insect endosymbionts described earlier by Costa et al. [6]. Since they were unculturable, these organisms have been described as ‘Candidatus Fritschea
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bemisiae’ and ‘Candidatus Fritschea eriococci’ [10]. The 98.5% cut-off was also used by Chua et al. [3] to separate Waddlia malaysiensis from fruit bats from Waddlia chondrophila from bovine foetuses, as well as by other authors to tentatively cluster the various novel chlamydiae [4,21]. Since the cockroach pathogen showed 16S rDNA sequence similarity of 96.3% with ‘Candidatus Rhabdochlamydia porcellionis’, we conclude that it represents a distinct microorganism and propose, based on phenotypic (the morphological similarity between both organisms), genetic and phylogenetic data, to name it ‘Candidatus Rhabdochlamydia crassificans’. Its affiliation within the order Chlamydiales is supported by the 80–90% sequence similarity with all the other members of that lineage. The parasite of B. orientalis was initially described as Rickettsiella crassificans by Radek [33], to denote the pronounced body swelling caused in infected cockroaches. More than 30 years previously, Huger [22] described R. blattae, later renamed R. popilliae [38], from a cockroach population obtained from the same stock collection of B. orientalis of the Federal Health Institute of Berlin, Germany. However, given some significant differences in size and morphology, these two endosymbionts are likely distinct organisms [33]. The present study clearly demonstrates the close phylogenetic relatedness, but not identity of ‘Candidatus Rhabdochlamydia crassificans’ with ‘Candidatus Rhabdochlamydia porcellionis’ [8,25]. The closest lineage, as inferred from 16S rDNA sequences (less than 90% sequence similarity), appears to be the one of the Simkaniaceae (Fig. 2), but the ultrastructural morphology of the known members of the genus Simkania [24] and ‘Candidatus Fritschea’ [6,36], is clearly different from that of ‘Candidatus Rhabdochlamydia’ [8,25,33]. This also underscores the importance of using the typical ultrastructural features of the elementary bodies (five-layered cell wall) as morphological taxonomic criteria. Other examples of the taxonomic value of ultrastructural differences for the classification of Chlamydiales are the Crescent Body, an infective stage only present within the Parachlamydiaceae [19], or the ‘‘head-and-tail form’’ shown for ‘Candidatus Piscichlamydia salmonis’ [7]. This is especially important given the few phenotypic traits that may be investigated for these obligate intracellular bacteria. In the future, further molecular studies should be performed to determine whether some members of the R. chironomi group may represent additional members of the ‘Candidatus Rhabdochlamydia’ lineage. It will be also important to characterize microbiologically other organisms, molecularly identified as closely related to ‘Candidatus Rhabdochlamydia’ [5], but for which no data beyond the 16S rDNA sequences are yet available, as for example the ECL VI cluster from activated sludge [21].
Rickettsiella species sensu lato comprise only pathogens of arthropods, with limited or absent pathogenic potential for vertebrates [38]. However, since some Rickettsiella species belong in fact to the Chlamydiales, a group including novel human and vertebrate pathogens, the potential pathogenicity of these microorganisms should be assessed. Currently, there are some molecular evidences for a human exposition to rhabdochlamydiae or closely related organisms, provided by Meijer and Ossewaarde [27], who amplified, cloned and sequenced 300-bp 16S rDNA CRG fragments from the aqueous humor of human patients suffering of uveitis. Two clones (CRG95 and CRG96) showed significant sequences similarities (95.1–95.5% similarity) with the genes of both ‘Candidatus Rhabdochlamydia’ species, whereas a third clone (CRG81), though exhibiting a lesser degree of similarity, was phylogenetically more closely related to ‘Candidatus Rhabdochlamydia’ sequences than to any other Chlamydiales sequences. In this work, we showed that even apparently healthy cockroaches may be infected by ‘Candidatus Rhabdochlamydia crassificans’. The presence of the bacteria in ovaries, including oocytes, as shown morphologically [33] and by PCR (this study), suggests that transovarial transmission could occur. Of note, ‘Candidatus Rhabdochlamydia crassificans’ is not only able to infect fat bodies and ovaries of B. orientalis, but may also infect many other cockroach tissues such as intestinal cells, Malpighian tubules and hemolyph cells [33]. If this novel chlamydia proves to be pathogenic for humans, the possible release of ‘Candidatus Rhabdochlamydia’ into the gut lumen of the Oriental cockroach and its consecutive excretion in the feces may have significant epidemiological consequences. Food contamination with ‘Candidatus Rhabdochlamydia crassificans’ may be especially relevant if this obligate intracellular bacteria is able to survive extracellularly for prolonged periods of time thank its five-layered cell wall. In the future, it will be interesting to evaluate the potential of cockroaches as environmental reservoir and vector of ‘Candidatus Rhabdochlamydia’ and other chlamydiae. It will also be important to determine whether ‘Candidatus Rhabdochlamydia’ may survive within free-living amoebae, since these protists harbour several different novel chlamydiae and represent a widespread environmental reservoir for several pathogenic intracellular bacteria [20].
Description of ‘Candidatus Rhabdochlamydia crassificans’ The name ‘Rhabdochlamydia’ is derived from the Greek word orhabdo4, which means stick/rod and from the Greek word ochlamys4 which means coat; ochlamydia4 is the taxonomic name of a bacterial
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genus; orhabdochlamydia4 refers to the rod-like shape of coated elementary bodies [25]. The name ‘crassificans’ is derived from the Latin words ocrassus4, which means thick and ofacere4 to make; it refers to the severe body swelling caused by ‘Candidatus Rhabdochlamydia crassificans’ in infected cockroaches [33]. ‘Candidatus Rhabdochlamydia crassificans’ encompasses the intracellular bacteria present within an inclusion in the fatbodies of the cockroach B. orientalis. Bacterial cells could not be grown on axenic media (data not shown). Bacteria exhibit a chlamydia-like developmental cycle, with elementary bodies, reticulate bodies and two additional intermediate stages, the flat bodies, which look like an enlarged, flattened elementary bodies, and the condensing sphere, which may undergo binary fission like reticulate bodies [33]. The elementary body is about 500 nm in length and 250 nm in width [33]. Its cell wall is typically composed of five layers (Fig. 1a). The cytoplasm of the elementary bodies is especially dense at one pole of the rod where 1 or 2 electron-light lamellae are present (Fig. 1a). At the other pole there is an oval structure with an array of ribosome-like granules. The reticulate bodies, that divide by binary fission (Fig. 1b), are the largest developmental stages (diameter of about 900 nm). Their cell wall is composed of three layers, including the plasma membrane [33]. On the basis of its 16S rRNA gene sequence, ‘Candidatus Rhabdochlamydia crassificans’ appears distinct from its closest neighbor, ‘Candidatus Rhabdochlamydia porcellionis’, and both are two yet uncultured bacteria of the order Chlamydiales. The 16S rRNA gene sequence of ‘Candidatus Rhabdochlamydia crassificans’ has been deposited on the NCBI website (http://www.ncbi.nlm. nih.gov/) under the GenBank accession no. AY223862. ‘Candidatus Rhabdochlamydia crassificans’ is also characterized by rod-shaped elementary bodies with an oblong structure in the cytoplasm and a typical fivelayered cell wall.
Acknowledgments We thank Mrs. Gabriele Schrader (Federal Health Institute of Berlin, Germany) for delivering the stock culture of B. orientalis cockroaches, and Philip Tarr (Lausanne, Switzerland) for reviewing the manuscript. Gilbert Greub is recipient of the Swiss National Science Foundation Grant no FN3200BO-105885.
[2]
[3]
[4]
[5] [6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
References [15] [1] T. Adekambi, M. Drancourt, Dissection of phylogenetic relationships among 19 rapidly growing Mycobacterium species by 16S rRNA, hsp65, sodA, recA and rpoB gene
227
sequencing,, Int. J. Syst. Evol. Microbiol. 54 (2004) 2095–2105. T.J. Bodetti, K. Viggers, K. Warren, R. Swan, S. Conaghty, C. Sims, P. Timms, Wide range of Chlamydiales types detected in native Australian marsupials, Vet. Microbiol. 96 (2003) 177–187. K.B. Chua, J.E. Corkill, P.S. Hooi, C. Winstanley, C.A. Hart, Waddlia malaysiensis: an obligate intracellular bacterium isolated from a fruit bat (Eonycteris spelaea), Emerg. Infect. Dis. 11 (2005) 271–277. D. Corsaro, M. Valassina, D. Venditti, Increasing diversity within chlamydiae, Crit. Rev. Microbiol. 29 (2003) 37–78. D. Corsaro, D. Venditti, Emerging chlamydial infection, Crit. Rev. Microbiol. 30 (2004) 75–106. H.S. Costa, D.M. Westcot, D.E. Ullman, R. Rosell, J.K. Brown, M.W. Johnson, Morphological variation in Bemisia endosymbionts, Protoplasma 189 (1995) 194–202. A. Draghi II, V.L. Popov, M.M. Kahl, J.B. Stanton, C.C. Brown, G.J. Tsongalis, A.B. West, S. Frasca Jr., Characterization of ‘Candidatus Piscichlamydia salmonis’ (Order Chlamydiales), a chlamydia-like bacterium associated with epitheliocystis in farmed Atlantic salmon (Salmo salar), J. Clin. Microbiol. 42 (2004) 5286–5297. D. Drobne, J. Strus, N. Znidarsic, P. Zidar, Morphological description of bacterial infection of digestive glands in the terrestrial isopod Porcellio scaber (Isopoda, Crustacea), J. Invertebr. Pathol. 73 (1999) 113–119. K.D.E. Everett, R.M. Bush, A.A. Andersen, Emended description of the order Chlamydiales, proposal of Parachlamydiaceae fam. nov., and Simkaniaceae fam. nov., each containing one monotypic genus, revised taxonomy of the family Chlamydiaceae, including a new genus and five new species and standards for the identification of organisms, Int. J. Syst. Bacteriol. 49 (1999) 415–440. K.D.E. Everett, M.L. Thao, M. Horn, G.E. Dyszynsky, P. Baumann, Novel chlamydiae in whiteflies and scale insects: endosymbionts ‘Candidatus Fritschea bemisiae’ strain Falk and ‘Candidatus Fritschea eriococci’ strain Elm, Int. J. Syst. Evol. Microbiol. 55 (2005) 1581–1587. B.A. Federici, Reproduction and morphogenesis of Rickettsiella chironomi an unusual intracellular prokaryotic parasite of midge larvae, J. Bacteriol. 143 (1980) 995–1002. O.A. Fischer, L. Matlova, L. Dvorska, P. Svastova, I. Pavlik, Nymphs of the Oriental cockroach (Blatta orientalis) as passive vectors of causal agents of avian tuberculosis and paratuberculosis, Med. Vet. Entomol. 17 (2003) 145–150. R. Fotedar, U. Banerjee, U.B. Shriniwas, Vector potential of the German cockroach in dissemination of Pseudomonas aeruginosa, J. Hosp. Infect. 23 (1993) 55–59. R. Fotedar, U.B. Shriniwas, A. Verma, Cockroaches (Blattella germanica) as carriers of microorganisms of medical importance in hospitals, Epidemiol. Infect. 107 (1991) 181–187. M.G. Friedman, B. Dvoskin, S. Kahane, Infections with the chlamydia-like microorganism Simkania negevensis a possible emerging pathogen, Microb. Infect. 5 (2003) 1013–1021.
ARTICLE IN PRESS 228
D. Corsaro et al. / Systematic and Applied Microbiology 30 (2007) 221–228
[16] R. Frutos, B.A. Federici, B. Revet, M. Bergoin, Taxonomic studies of Rickettsiella, Rickettsia and Chlamydia using genomic DNA, J. Invertebr. Pathol. 63 (1994) 294–300. [17] R. Frutos, M. Pages, M. Bellis, G. Roizes, M. Bergoin, Pulsed-field gel electrophoresis determination of the genome size of obligate intracellular bacteria belonging to the genera Chlamydia, Rickettsiella and Porochlamydia, J. Bacteriol. 171 (1989) 4511–4513. [18] G. Greub, D. Raoult, Parachlamydiaceae: potential emerging pathogens, Emerg. Infect. Dis. 8 (2002) 625–630. [19] G. Greub, D. Raoult, Crescent bodies of Parachlamydia acanthamoeba and its life cycle within Acanthamoeba polyphaga: an electron micrograph study, Appl. Environ. Microbiol. 68 (2002) 3076–3084. [20] G. Greub, D. Raoult, Microorganisms resistant to freeliving amoebae, Clin. Microbiol. Rev. 17 (2004) 413–433. [21] M. Horn, M. Wagner, Evidence for additional genus-level diversity of Chlamydiales in the environment, FEMS Microbiol. Lett. 204 (2001) 71–74. [22] A. Huger, Eine Rickettsiose der Orientalischen Schabe, Blatta orientalis L., verursacht durch Rickettsiella blattae nov. spec., Naturwissenschaften 51 (1964) 22. [23] S. Imamura, M. Kita, Y. Yamaoka, T. Yamamoto, A. Ishimaru, H. Konishi, N. Wakabayashi, S. Mitsufuji, T. Okanoue, J. Imanishi, Vector potential of cockroaches for Helicobacter pylori infection, Am. J. Gastroenterol. 98 (2003) 1500–1503. [24] S. Kahane, N. Kimmel, M.G. Friedman, The growth cycle of Simkania negevensis, Microbiology 148 (2002) 735–742. [25] R. Kostanjsek, J. Strus, D. Drobne, G. Avgustin, Candidatus Rhabdochlamydia porcellionis, gen. nov., sp. nov., an intracellular bacterium from hepatopancreas of the terrestrial isopod Porcellio scaber, Int. J. Syst. Evol. Microbiol. 54 (2004) 543–549. [26] S. Kumar, K. Tamura, I.B. Jakobsen, M. Nei, MEGA2: molecular evolutionary genetics analysis software, Bioinformatics 17 (2001) 1244–1245. [27] A. Meijer, J.M. Ossewaarde, Description of a wider diversity within the order Chlamydiales than curreltly classified. International Chlamydia Conference, Antalya, Turkey, 16–21 June 2002. /http://www.chlamydiae. comS [Online.] [28] R. Michel, K.D. Mu¨ller, L. Zo¨ller, J. Walochnick, M. Hartmann, E.N. Schmid, Free-living amoebae serve as
[29]
[30]
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
[39]
[40]
host for the chlamydia-like bacterium Simkania negevensis, Acta Protozool 44 (2005) 113–121. R. Michel, M. Steinert, L. Zo¨ller, B. Hauro¨der, K. Henning, Free-living amoebae may serve as hosts for the Chlamydia-like bacterium Waddlia chondrophila isolated from an aborted bovine foetus, Acta Protozool. 43 (2004) 37–42. G. Morel, Studies of Porochlamydia buthi g. n., sp. n., an intracellular pathogen of the scorpion Buthus occitanus, J. Invertebr. Pathol. 26 (1976) 167–175. G. Morel, E´tude d’une Rickettsiella (Rickettsie) se de´veloppant chez un arachnide, l’araigne´e Pisaura mirabilis, Ann. Microbiol. Inst. Pasteur 128A (1977) 49–59. H.H. Pai, W.C. Chen, C.F. Peng, Isolation of nontuberculous mycobacteria from hospital cockroaches (Periplaneta americana), J. Hosp. Infect. 53 (2003) 224–228. R. Radek, Light and electron microscopic study of a Rickettsiella species from the cockroach Blatta orientalis, J. Invertebr. Pathol. 76 (2000) 249–256. V. Roux, M. Bergoin, N. Lamaze, D. Raoult, Reassessment of the taxonomic position of Rickettsiella grylli, Int. J. Syst. Bacteriol. 47 (1997) 1255–1257. G. Soldati, Z.H. Lu, L. Vaughan, A. Polkinghorne, D.R. Zimmermann, J.B. Huder, A. Pospischil, Detection of mycobacteria and chlamydiae in granulomatous inflammation of reptiles: a retrospective study, Vet. Pathol. 41 (2004) 388–397. M.L. Thao, L. Baumann, J.M. Hess, B.W. Falk, J.C.K. Ng, P.J. Gullan, P. Baumann, Phylogenetic evidence for two new insect-associated chlamydia of the family Simkaniaceae, Curr. Microbiol. 47 (2003) 46–50. W.G. Weisburg, S.M. Barns, D.A. Pelletier, D.J. Lane, 16S ribosomal DNA amplification for phylogenetic study, J. Bacteriol. 173 (1991) 697–703. E. Weiss, G.A. Dasch, K.P. Chang, Genus VIII. Rickettsiella Philip 1956, 267AL, in: N.R. Krieg, J.G. Holt (Eds.), Bergey’s Manual of Systematic Bacteriology, vol. 1, Williams & Wilkins, Baltimore, MD, 1984, pp. 713–717. E. Weiss, J.W. Moulder, Genus III. Coxiella Philip 1948, 58AL, in: N.R. Krieg, J.G. Holt (Eds.), Bergey’s Manual of Systematic Bacteriology, vol. 1, Williams & Wilkins, Baltimore, MD, 1984, pp. 701–704. L. Zurek, C. Schal, Evaluation of the German cockroach (Blattella germanica) as a vector for verotoxigenic E. coli F18 in confined swine production, Vet. Microbiol. 101 (2004) 263–267.
