Periplaneta americana (Blattodea: Blattidae) fungal pathogens in hospital sewer systems: molecular and phylogenetic approaches.

Cockroaches are known as mechanical vectors of some pathogens that can infect humans. The present study aims to rapidly identify Periplaneta americana fungal pathogens from sewer systems of public hospitals in Esfahan using the polymerase chain reaction (PCR) technique. A total of 55 P. americana cockroaches were randomly collected by direct trapping from sewer systems of seven hospitals and screened for fungal infectious agents using standard morphological methods and the PCR sequencing. From the American cockroach, we isolated 62 yeasts and 31 molds from the surface, hemocoel, and digestive tract of P. americana. Based on DNA sequence comparisons and other taxonomic characteristics, they were identified as more than four species of yeast and four species of mold. Yeast species including Pichia kudriavzevii, Candida glabrata, Pichia kluyveri, and Candida viswanathii, and molds such as Aspergillus niger, Penicillium italicum, Mucor plumbeus, and Rhizopus oryzae were isolated repeatedly from the surface, hemocoel, and digestive tract of P. americana. Our results show that the use of a combination of morphological, molecular techniques, and phylogenetic analysis can lead to the identification of pathogenic fungal agents in American cockroaches and also knowledge of fungal pathogens-arthropod host relationships.

Wolbachia infection in native populations of Blattella germanica and Periplaneta americana.

Cockroaches are significant pests worldwide, being important in medical, veterinary, and public health fields. Control of cockroaches is difficult because they have robust reproductive ability and high adaptability and are resistant to many insecticides. Wolbachia is an endosymbiont bacterium that infects the reproductive organs of approximately 70% of insect species and has become a promising biological agent for controlling insect pests. However, limited data on the presence or strain typing of Wolbachia in cockroaches are available. PCR amplification and sequencing of the wsp and gltA genes were used to study the presence, prevalence and molecular typing of Wolbachia in two main cockroach species, Blattella germanica (German cockroach) and Periplaneta americana (American cockroach), from different geographical locations of Iran. The Wolbachia endosymbiont was found only in 20.6% of German cockroaches while it was absent in American cockroach samples. Blast search and phylogenetic analysis revealed that the Wolbachia strain found in the German cockroach belongs to Wolbachia supergroup F. Further studies should investigate the symbiotic role of Wolbachia in cockroaches and determine whether lack of Wolbachia infection may increase this insect's ability to tolerate or acquire various pathogens. Results of our study provide a foundation for continued work on interactions between cockroaches, bacterial endosymbionts, and pathogens.

Histological Findings in Captive Madagascar Hissing Cockroaches (Gromphadorhina portentosa) and a Literature Review.

Madagascar hissing cockroaches (MHC, Gromphadorhina portentosa) are members of the Blaberidae (giant cockroaches) family of the Insecta class. They are native to the African island of Madagascar where they live within leaf litter on the rainforest floor. Due to their large size, relative tameness, and general easy keeping, they have become popular in classrooms, zoological collections, museums, research laboratories, and as private exotic pets; however, descriptions of diseases of MHC in the literature are rare. The objective of this study is to describe and characterize postmortem histological findings in 18 captive MHC from a single zoological collection. In this retrospective study, 18 (4 females and 14 males) adult MHC necropsies were submitted to Northwest ZooPath between 2016 and 2020 for evaluation. The main organs with histological lesions were chitinous gut (foregut and/or hindgut; n = 17), tracheae (n = 15), fat body (n = 14), ventriculus (midgut) (n = 13), body wall (n = 12), Malpighian tubules (n = 12), and hemolymphatic sinuses (n = 12). All animals had inflammatory lesions affecting various organs. Inflammatory lesions typically consisted of aggregates of hemocytes with variable amounts of melanization and/or encapsulation. Bacterial, fungal, and parasitic infections were common and variably associated with hemocytic inflammation. Many of these organisms may represent symbiotic organisms of the MHC that cause opportunistic infections. This study contributes to the current knowledge of pathological findings and disease response of MHC and reviews diseases reported in multiple cockroach species.

Coevolution of Metabolic Pathways in Blattodea and Their Blattabacterium Endosymbionts, and Comparisons with Other Insect-Bacteria Symbioses.

Many insects harbor bacterial endosymbionts that supply essential nutrients and enable their hosts to thrive on a nutritionally unbalanced diet. Comparisons of the genomes of endosymbionts and their insect hosts have revealed multiple cases of mutually-dependent metabolic pathways that require enzymes encoded in 2 genomes. Complementation of metabolic reactions at the pathway level has been described for hosts feeding on unbalanced diets, such as plant sap. However, the level of collaboration between symbionts and hosts that feed on more variable diets is largely unknown. In this study, we investigated amino acid and vitamin/cofactor biosynthetic pathways in Blattodea, which comprises cockroaches and termites, and their obligate endosymbiont Blattabacterium cuenoti (hereafter Blattabacterium). In contrast to other obligate symbiotic systems, we found no clear evidence of "collaborative pathways" for amino acid biosynthesis in the genomes of these taxa, with the exception of collaborative arginine biosynthesis in 2 taxa, Cryptocercus punctulatus and Mastotermes darwiniensis. Nevertheless, we found that several gaps specific to Blattabacterium in the folate biosynthetic pathway are likely to be complemented by their host. Comparisons with other insects revealed that, with the exception of the arginine biosynthetic pathway, collaborative pathways for essential amino acids are only observed in phloem-sap feeders. These results suggest that the host diet is an important driving factor of metabolic pathway evolution in obligate symbiotic systems. IMPORTANCE The long-term coevolution between insects and their obligate endosymbionts is accompanied by increasing levels of genome integration, sometimes to the point that metabolic pathways require enzymes encoded in two genomes, which we refer to as "collaborative pathways". To date, collaborative pathways have only been reported from sap-feeding insects. Here, we examined metabolic interactions between cockroaches, a group of detritivorous insects, and their obligate endosymbiont, Blattabacterium, and only found evidence of collaborative pathways for arginine biosynthesis. The rarity of collaborative pathways in cockroaches and Blattabacterium contrasts with their prevalence in insect hosts feeding on phloem-sap. Our results suggest that host diet is a factor affecting metabolic integration in obligate symbiotic systems.

Comparative study of gut microbiota from decomposer fauna in household composter using metataxonomic approach.

Household composter is one of the fragmented habitats, which still ensures the survival of many animals, especially decomposer fauna. The components of organic matter in the composter are complex, thus providing opportunities for obtaining high diversity of decomposer fauna. The ability of decomposer fauna to break down organic matter may be supported by their gut microbiota. In this study, we compared the diversity, the abundance and distribution of gut prokaryotic microbiota among several decomposer fauna members, namely cockroaches, millipedes, beetle larvae, and snails, as well as the compost from a household composter in Surabaya, Indonesia, using a metataxonomic approach. Microbial community DNA was isolated from the guts of four types of dominant decomposer fauna and the compost. A total of 42 phyla and 497 genera were observed in five samples with the predominant bacteria belonging to the Proteobacteria phylum which appeared in all samples. The highest diversity of gut bacteria was found in cockroach although not higher than the compost as a habitat for the decomposer fauna. A total of 1131 operational taxonomic units derived from 232 genera were found in compost and guts of four decomposer fauna species. Similarities between the microbial community structures found in the gut of the four decomposer fauna to those found in compost indicated that the environment had a strong effect on the overall gut microbiota of the decomposer fauna.

The utilization of Blaptica dubia cockroaches as an in vivo model to test antibiotic efficacy.

Insects are now well recognized as biologically relevant alternative hosts for dozens of mammalian pathogens and they are routinely used in microbial pathogenesis studies. Unfortunately, these models have yet to be incorporated into the drug development pipeline. The purpose of this work was to begin to evaluate the utility of orange spotted (Blaptica dubia) cockroaches in early antibiotic characterization. To determine whether these model hosts could exhibit mortality when infected with bacteria that are pathogenic to humans, we subjected B. dubia roaches to a range of infectious doses of Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii to identify the medial lethal dose. These results showed that lethal disease did not develop following infection of high doses of S. aureus, and A. baumannii. However, cockroaches infected with E. coli and K. pneumoniae succumbed to infection (LD50s of 5.82 × 106 and 2.58 × 106 respectively) suggesting that this model may have limitations based on pathogen specificity. However, because these cockroaches were susceptible to infection from E. coli and K. pneumoniae, we used these bacterial strains for subsequent antibiotic characterization studies. These studies suggested that ß-lactam antibiotic persistence and dose was associated with reduction of hemolymph bacterial burden. Moreover, our data indicated that the reduction of bacterial CFU was directly due to the drug activity. Altogether, this work suggests that the orange-spotted cockroach infection model provides an alternative in vivo setting from which antibiotic efficacy can be evaluated.

Reduced production of the major allergens Bla g 1 and Bla g 2 in Blattella germanica after antibiotic treatment.

PURPOSE: Allergens present in the feces or frass of cockroaches can cause allergic sensitization in humans. The use of fecal and frass extracts for immunotherapy has been previously investigated but has not yet been fully standardized. Here, we treated cockroaches with ampicillin to produce extracts with reduced amounts of total bacteria. METHODS: We performed targeted high-throughput sequencing of 16S rDNA to compare the microbiomes of ampicillin-treated and untreated (control) cockroaches. RNA-seq was performed to identify differentially expressed genes (DEGs) in ampicillin-treated cockroaches. RESULTS: Analysis of the microbiome revealed that alpha diversity was lower in the ampicillin-treated group than in the control group. Beta diversity analysis indicated that ampicillin treatment altered bacterial composition in the microbiome of cockroaches. Quantitative polymerase chain reaction revealed that almost all bacteria were removed from ampicillin-treated cockroaches. RNA-seq analysis revealed 1,236 DEGs in ampicillin-treated cockroaches (compared to untreated cockroaches). Unlike bacterial composition, the DEGs varied between the two groups. Among major allergens, the expression of Bla g 2 decreased significantly in ampicillin-treated cockroaches (compared to untreated group). CONCLUSIONS: In this study, the reduced level of allergens observed in cockroaches may be related to lower amounts of total bacteria caused by treatment with antibiotics. It is possible to make a protein extract with few bacteria for use in immunotherapy.

Potential value and chemical characterization of gut microbiota derived nitrogen containing metabolites in feces from Periplaneta americana (L.) at different growth stages.

The American cockroach, Periplaneta americana (L.), is able to highly survive in various complicated environments around the globe, and often considered as a pest. In contrast, billions of P. americana have been massively reared in China and extensively used as a medicinal insect, due to its function for preventing and treating ulceration and heart failure. Considering the possibility that microbiota-derived metabolites could be an effective source to identify promising candidate drugs, we attempted to establish a rapid method for simultaneous determination of gut microbiota metabolites from medicinal insects. In this study, network pharmacology approach and ultra-performance liquid chromatography (UPLC) technique were employed to reveal the potential pharmacological activity and dynamics variation of nitrogen-containing metabolites (NCMs) originated from the gut microbiota of breeding P. americana at different growth stages. A metabolites-targets-diseases network showed that NCMs are likely to treat diseases such as ulceration and cancer. The analysis of NCMs' content with the growth pattern of P. americana indicated that the content of NCMs declined with P. americana aging. Both principal component analysis and orthogonal partial least squares discriminant analysis suggested that 8-hydroxy-2-quinolinecarboxylic acid and 8-hydroxy-3,4-dihydro-2(1H)-quinolinone are the potential differential metabolic markers for discriminating between nymphs and adults of P. americana. Moreover, the developed UPLC method showed an excellent linearity (R2 > 0.999), repeatability (RSD < 2.6%), intra- and inter-day precisions (RSD < 2.2%), and recovery (95.5%-99.0%). Collectively, the study provides a valuable strategy for analyzing gut microbiota metabolites from insects and demonstrates the prospects for discovering novel drug candidates from the feces of P. americana.

Enhanced Mutation Rate, Relaxed Selection, and the "Domino Effect" are associated with Gene Loss in Blattabacterium, A Cockroach Endosymbiont.

Intracellular endosymbionts have reduced genomes that progressively lose genes at a timescale of tens of million years. We previously reported that gene loss rate is linked to mutation rate in Blattabacterium, however, the mechanisms causing gene loss are not yet fully understood. Here, we carried out comparative genomic analyses on the complete genome sequences of a representative set of 67 Blattabacterium strains, with sizes ranging between 511 and 645 kb. We found that 200 of the 566 analyzed protein-coding genes were lost in at least one lineage of Blattabacterium, with the most extreme case being one gene that was lost independently in 24 lineages. We found evidence for three mechanisms influencing gene loss in Blattabacterium. First, gene loss rates were found to increase exponentially with the accumulation of substitutions. Second, genes involved in vitamin and amino acid metabolism experienced relaxed selection in Cryptocercus and Mastotermes, possibly triggered by their vertically inherited gut symbionts. Third, we found evidence of epistatic interactions among genes leading to a "domino effect" of gene loss within pathways. Our results highlight the complexity of the process of genome erosion in an endosymbiont.

First record of gregarine protists (Apicomplexa: Sporozoa) in Asian fungus-growing termite Macrotermes barneyi (Blattaria: Termitidae).

Macrotermes barneyi, widely distributed in southern China, is the major fungus-growing termite in the subfamily Macrotermitinae. It has no flagellated protists in the guts. Here, we report occurrence of gregarine, a protozoan parasite in the digestive tract of M. barneyi. The general morphology and ultrastructure of the gregarine gamonts and syzygies by light micrograph and scanning electron micrograph are presented. SSU rDNA sequence analysis showed that the termite gregarine has the highest identity (90.10%) to that of Gregarina blattarum from cockroaches. Phylogenetic analysis based on the SSU rDNA sequences from diverse insect eugregarines indicated that the gregarine from M. barneyi is phylogenetically close to G. blattarus, L. erratica and G. tropica from Gregarinidae and Leidyanidae families, and may represent a novel species. This study expands our knowledge about the diversity of terrestrial eugregarines parasitizing in termites.

Long rDNA amplicon sequencing of insect-infecting nephridiophagids reveals their affiliation to the Chytridiomycota and a potential to switch between hosts.

Nephridiophagids are unicellular eukaryotes that parasitize the Malpighian tubules of numerous insects. Their life cycle comprises multinucleate vegetative plasmodia that divide into oligonucleate and uninucleate cells, and sporogonial plasmodia that form uninucleate spores. Nephridiophagids are poor in morphological characteristics, and although they have been tentatively identified as early-branching fungi based on the SSU rRNA gene sequences of three species, their exact position within the fungal tree of live remained unclear. In this study, we describe two new species of nephridiophagids (Nephridiophaga postici and Nephridiophaga javanicae) from cockroaches. Using long-read sequencing of the nearly complete rDNA operon of numerous further species obtained from cockroaches and earwigs to improve the resolution of the phylogenetic analysis, we found a robust affiliation of nephridiophagids with the Chytridiomycota-a group of zoosporic fungi that comprises parasites of diverse host taxa, such as microphytes, plants, and amphibians. The presence of the same nephridiophagid species in two only distantly related cockroaches indicates that their host specificity is not as strict as generally assumed.

Disentangling the Relative Roles of Vertical Transmission, Subsequent Colonizations, and Diet on Cockroach Microbiome Assembly.

A multitude of factors affect the assemblies of complex microbial communities associated with animal hosts, with implications for community flexibility, resilience, and long-term stability; however, their relative effects have rarely been deduced. Here, we use a tractable lab model to quantify the relative and combined effects of parental transmission (egg case microbiome present/reduced), gut inocula (cockroach versus termite gut provisioned), and varying diets (matched or unmatched with gut inoculum source) on gut microbiota structure of hatchlings of the omnivorous cockroach Shelfordella lateralis using 16S rRNA gene (rDNA) amplicon sequencing. We show that the presence of a preexisting bacterial community via vertical transmission of microbes on egg cases reduces subsequent microbial invasion, suggesting priority effects that allow initial colonizers to take a strong hold and which stabilize the microbiome. However, subsequent inoculation sources more strongly affect ultimate community composition and their ecological networks, with distinct host-taxon-of-origin effects on which bacteria establish. While this is so, communities respond flexibly to specific diets in ways that consequently impact predicted community functions. In conclusion, our findings suggest that inoculations drive communities toward different stable states depending on colonization and extinction events, through ecological host-microbe relations and interactions with other gut bacteria, while diet in parallel shapes the functional capabilities of these microbiomes. These effects may lead to consistent microbial communities that maximize the extended phenotype that the microbiota provides the host, particularly if microbes spend most of their lives in host-associated environments.IMPORTANCE When host fitness is dependent on gut microbiota, microbial community flexibility and reproducibility enhance host fitness by allowing fine-tuned environmental tracking and sufficient stability for host traits to evolve. Our findings lend support to the importance of vertically transmitted early-life microbiota as stabilizers, through interactions with potential colonizers, which may contribute to ensuring that the microbiota aligns within host fitness-enhancing parameters. Subsequent colonizations are driven by microbial composition of the sources available, and we confirm that host-taxon-of-origin affects stable subsequent communities, while communities at the same time retain sufficient flexibility to shift in response to available diets. Microbiome structure is thus the result of the relative impact and combined effects of inocula and fluctuations driven by environment-specific microbial sources and digestive needs. These affect short-term community structure on an ecological time scale but could ultimately shape host species specificities in microbiomes across evolutionary time, if environmental conditions prevail.

Bacteriocytes and Blattabacterium Endosymbionts of the German Cockroach Blattella germanica, the Forest Cockroach Blattella nipponica, and Other Cockroach Species.

Cockroaches are commonly found in human residences and notorious as hygienic and nuisance pests. Notably, however, no more than 30 cockroach species are regarded as pests, while the majority of 4,500 cockroaches in the world are living in forest environments with little relevance to human life. Why some cockroaches have exceptionally adapted to anthropic environments and established pest status is of interest. Here we investigated the German cockroach Blattella germanica, which is a cosmopolitan pest species, and the forest cockroach Blattella nipponica, which is a wild species closely related to B. germanica. In contrast to easy rearing of B. germanica, laboratory rearing of B. nipponica was challenging-several trials enabled us to keep the insects for up to three months. We particularly focused on the distribution patterns of specialized cells, bacteriocytes, for harboring endosymbiotic Blattabacterium, which has been suggested to contribute to host's nitrogen metabolism and recycling, during the postembryonic development of the insects. The bacteriocytes were consistently localized to visceral fat bodies filling the abdominal body cavity, where a number of single bacteriocytes were scattered among the adipocytes, throughout the developmental stages in both females and males. The distribution patterns of the bacteriocytes were quite similar between B. germanica and B. nipponica, and also among other diverse cockroach species, plausibly reflecting the highly conserved cockroach-Blattabacterium symbiotic association over evolutionary time. Our study lays a foundation to experimentally investigate the origin and the processes of urban pest evolution, on account of possible involvement of microbial associates.

The interaction between cuticle free fatty acids (FFAs) of the cockroaches Blattella germanica and Blatta orientalis and hydrolases produced by the entomopathogenic fungus Conidiobolus coronatus.

The interactions between entomopathogenic fungi and insects serve a classic example of a co-evolutionary arms race between pathogens and their target host. The cuticle, site of the first contact between insects and entomopathogenic fungus, is an important defensive barrier against pathogens. It is covered by a layer of lipids that appears to play a key role in these processes and cuticular free fatty acid (FFA) profiles are consider as a determinant of susceptibility, or resistance, to fungal infections. These profiles are species-specific. The cockroaches Blattella germanica (Blattodea: Blattidae) and Blatta orientalis (Blattodea: Ectobiidae) are unsusceptible to the soil fungus Conidiobolus coronatus (Entomophthorales: Ancylistaceae) infection, therefore we studied the profiles of FFAs in order to understand the defensive capabilities of the cockroaches. The fungus was cultivated for three weeks in minimal medium. Cell-free filtrate was obtained, assayed for elastase, N-acetylglucosaminidase, chitobiosidase and lipase activity, and then used for in vitro hydrolysis of the cuticle from wings and thoraces of adults and oothecae. The amounts of amino acids, N-glucosamine and FFAs released from the hydrolysed cuticle samples were measured after eight hours of incubation. The FFA profiles of the cuticle of adults, and the wings, thoraces and oothecae of both species were established using GC-MS and the results were correlated with the effectiveness of fungal proteases, chitinases and lipases in the hydrolyzation of cuticle samples. Positive correlations would suggest the existence of compounds used by the fungus as nutrients, whereas negative correlations may indicate that these compounds could be engaged in insect defence.

A Myanmar amber cockroach with protruding feces contains pollen and a rich microcenosis.

Early endosymbiotic interactions are recorded only from a Cretaceous termite and a cockroach. Mesoblatta maxi Hinkelman, gen. et sp. nov. is the second representative of the dominant, cosmopolitan Mesozoic family Mesoblattinidae known from Cenomanian northern Myanmar amber, and the fourteenth from both amber and sedimentary rocks. Unique characters are rare (n = 19), symplesiomorphies are frequent (n = 140), and foremost is a standard maxillary palp, an irregular area between forewing veins radius and media, central ocellus, and multisegmented styli, suggesting an ancestral position with respect to Blattidae. Autapomorphies of this otherwise conservative taxon are only its large size and a short probasitarsus. Two nymphs with fecal pellets protruding from their body, Blattocoprolites mesoblattamaxi Hinkelman, ichogen. et ichnosp. nov., represent the first cockroaches with formalized coprolites (along with Blattocoprolites blattulidae Hinkelman, ichnosp. nov. established herein from Lebanese amber) and provide evidence of burial defecation. Subhomogenic consistency of coprolites with mucous components, "pseudoinclusions," leaf, trichia, wood debris, cycad pollen, endosymbiotic protists, and epibiotic bacteria directly document pollen transfer through the digestive tract and the earliest coevolution with protists and bacteria. Other post-burial fecal bacteria at the surface are documented for the first time in the Mesozoic, directly indicating structured dung processing. Reference samples (as well as almost all Myanmar amber samples) contain numerous "pseudoinclusions," probably representing damaged or dead cysts of Chlamydomonas hanublikanus Vrsanská et Hinkelman, sp. nov. established on the basis of its reproductive stages (with an origin within the resin inside the tree). These are documented together with green algae, including Spirogyra Nees, 1820; flagellates; and flagellate amoebae, promoting massive future microbiota studies.

Nutritional symbiosis and ecology of host-gut microbe systems in the Blattodea.

Cockroaches and termites (Order: Blattodea) have been the subject of substantial research attention for over a century due, in part, to a subset of them having a strong propensity to cohabitate with humans and their structures. Recent research has led to numerous insights into their behavior, physiology, and ecology, as well as their ability to harbor taxonomically diverse microbial communities within their digestive systems, which include taxa that contribute to host growth and development. Further, recent investigations into the physiological and behavioral adaptations that enable recalcitrant polysaccharide digestion and the maintenance of microbial symbionts in cockroaches and termites suggests that symbionts contribute significantly to nutrient provisioning and processing.

Phylosymbiosis across Deeply Diverging Lineages of Omnivorous Cockroaches (Order Blattodea).

The gut microbiome is shaped by both host diet and host phylogeny. However, separating the relative influence of these two factors over long periods of evolutionary time is often difficult. We conducted a 16S rRNA gene amplicon-based survey of the gut microbiome from 237 individuals and 19 species of omnivorous cockroaches from the order Blattodea. The order Blattodea represents an ancient lineage of insects that emerged over 300 million years ago, have a diverse gut microbiota, and have a typically gregarious lifestyle. All cockroaches shared a broadly similar gut microbiota, with 66 microbial families present across all species and 13 present in every individual examined. Although our network analysis of the cockroach gut microbiome showed a large amount of connectivity, we demonstrated that gut microbiota cluster strongly by host species. We conducted follow-up tests to determine if cockroaches exhibit phylosymbiosis, or the tendency of host-associated microbial communities to parallel the phylogeny of related host species. Across the full data set, gut microbial community similarity was not found to correlate with host phylogenetic distance. However, a weak but significant phylosymbiotic signature was observed using the matching cluster metric, which allows for localized changes within a phylogenetic tree that are more likely to occur over long evolutionary distances. This finding suggests that host phylogeny plays a large role in structuring the cockroach gut microbiome over shorter evolutionary distances and a weak but significant role in shaping the gut microbiome over extended periods of evolutionary time.IMPORTANCE The gut microbiome plays a key role in host health. Therefore, it is important to understand the evolution of the gut microbiota and how it impacts, and is impacted by, host evolution. In this study, we explore the relationship between host phylogeny and gut microbiome composition in omnivorous, gregarious cockroaches within the Blattodea order, an ancient lineage that spans 300 million years of evolutionary divergence. We demonstrate a strong relationship between host species identity and gut microbiome composition and found a weaker but significant role for host phylogeny in determining microbiome similarity over extended periods of evolutionary time. This study advances our understanding of the role of host phylogeny in shaping the gut microbiome over different evolutionary distances.

Household cockroaches carry CTX-M-15-, OXA-48- and NDM-1-producing enterobacteria, and share beta-lactam resistance determinants with humans.

BACKGROUND: This study was designed to investigate whether household cockroaches harbor cephalosporin-resistant enterobacteria that share resistance determinants with human inhabitants. From February through July 2016, whole cockroach homogenates and human fecal samples from 100 households were cultured for cephalosporin-resistant enterobacteria (CRe). The CRe were examined for plasmid-mediated AmpC, ESBL, and carbapenemase genes; antibiotic susceptibility patterns; and conjugative transfer of antibiotic resistance mechanisms. Clonal associations between CRe were determined by multi-locus sequence typing (MLST). RESULTS: Twenty CRe were recovered from whole cockroach homogenates from 15 households. The prevalence of households with cockroaches that harbored CRe, AmpC- (based on phenotype, with no identifiable blaAmpC genes), ESBL-, and carbapenemase-producers were 15, 4, 5%(2 blaCTX-M-15/TEM-1; 1 blaCTX-M-15/TEM-4; 1 blaTEM-24; 1 blaSHV-4) and 3%(2 blaNDM-1 genes and 1 blaOXA-48 gene), respectively. Overall, 20 CRe were recovered from 61 fecal samples of inhabitants from all 15 households that had cockroach samples positive for CRe. Of these, 5CRe (1 per household) were positive for ESBLs (blaTEM-24, blaTEM-14, blaCTX-M-15/TEM-4, blaSHV-3, blaCTX-M-15/TEM-1) and none carried AmpCs or carbapenemases. From 4% of households, the pair of cockroach and human CRe shared the same sequence type (ST), clonal complex (CC), antibiogram, and conjugable bla gene sequence (house 34, E. coli ST9/CC20-blaTEM-4; house 37, E. coli ST44/CC10-blaCTX-15/TEM-4; house 41, E. coli ST443/CC205-blaCTX-15/TEM-1; house 49, K. pneumoniae ST231/CC131-blaSHV-13). CONCLUSION: The findings provide evidence that household cockroaches may carry CTX-M-15-, OXA-48- and NDM-1-producers, and share clonal relationship and beta-lactam resistance determinants with humans.