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Symbiosis in an overlooked microcosm: a systematic review of the bacterial flora of mites.

A dataset of bacterial diversity found in mites was compiled from 193 publications (from 1964 to January 2015). A total of 143 mite species belonging to the 3 orders (Mesostigmata, Sarcoptiformes and Trombidiformes) were recorded and found to be associated with approximately 150 bacteria species (in 85 genera, 51 families, 25 orders and 7 phyla). From the literature, the intracellular symbiont Cardinium, the scrub typhus agent Orientia, and Wolbachia (the most prevalent symbiont of arthropods) were the dominant mite-associated bacteria, with approximately 30 mite species infected each. Moreove…

In vitro Synergism between Chloroquine and Antibiotics against Orientia tsutsugamushi.

BACKGROUND: To investigate whether chloroquine enhances the effect of antibiotics against Orientia tsutsugamushi, the causative organism of scrub typhus, we compared the effect of antibiotics in combination with chloroquine with the effect of antibiotics alone in vitro. MATERIALS AND METHODS: The Boryong or AFSC-4 strain was inoculated into ECV304 cells, and incubated in medium containing doxycycline (4 µg/mL), rifampin (4 µg/mL), azithromycin (0.5 µg/mL), chloroquine (1 µg/mL), and each of these antibiotics in combination with chloroquine for 7 d. Immunofluorescence (IF) staining for O. tsut…

Инфекция Рикитсия цуцугамуши в клеточной культуре: антибиотическая подверженность, определяемая цитометрией потока.

Недавние неопубликованные сообщения из северного Таиланда о серьезных, а иногда и смертельных случаях скруба тифа, несмотря на соответствующую антибиотикическую терапию, свидетельствуют о том, что сопротивление может иметь место. Нынешние методы антибиотической восприимчивости, в которых используются прямые микроскопические подсчеты клеток Giemsa или анализы защиты мышей, медленные, трудоемкие и дорогостоящие. Мы изучали использование цитометрии потока для измерения рикетсиальной инфекции in vitro в клетках L-929, обработанных и не содержащих доксициклина, ципрофлоксацина, эритромицина и хлорэ

Совпадение в аннотации оригинала
Recent unpublished reports from northern Thailand of severe and sometimes fatal cases of scrub typhus, despite appropriate antibiotic therapy, suggest that resistance may occur. Current antibiotic susceptibility methods that use direct microscopic counts of Giemsa-stained cells or mouse protection assays are slow, labor-intensive, and expensive. We explored …

Seasonal development of Leptotrombidium pallidum (Acari: Trombiculidae) observed by experimental rearing in the natural environment.

Engorged larvae of Leptotrombidium pallidum Nagayo, Miyagawa, Mitamura & Tamiya, the vector mite of scrub typhus in Japan, were reared by feeding them with fresh eggs of the collembolan Sinella curviseta Brook while confined in small plastic containers under natural conditions in a copse. The larvae were collected from wild rodents (Apodemus speciosus) in autumn 1985 and spring 1986. Adults were kept alive for 2 yr or longer. The larvae obtained in autumn became dormant in the cold winter season, and growth recommenced in the spring. Thus, the development of mites collected in April became syn…

Epidemiology of rickettsial diseases.

Rickettsial diseases have a diversity of epidemiologic characteristics reflective of the variety of ecologic situations in which the obligate intracellular bacteria are transmitted to humans. For the spotted fever group (SFG) rickettsiae, Rickettsia typhi, R. tsutsugamushi, Coxiella burnetii, and the human ehrlichial agent, humans are a dead-end host who plays no role in the maintenance of the organism in nature. All rickettsioses exist as zoonoses. Moreover, all rickettsiae are found in infected arthopods, which generally serve as the natural hosts and can transmit the infection to the next g

A high-resolution nested PCR assay for genotyping Orientia tsutsugamushi based on a defined 700 bp segment of the TSA56 gene.

OBJECTIVES: To define a reproducibly specified TSA56 fragment that preserves genotype assignment relative to the full-length gene and to est … workflow supports reproducible TSA56 genotyping and more comparable sequence-based surveillance of scrub typhus.

Acute Febrile Illness With Triple Co-Infection: A Case Report on the Diagnostic Challenges of Overlapping Febrile Illnesses.

A 35-year-old female presented with 5 days of fever, fatigue, and myalgia during the post-monsoon season at Damak Hospital, Jhapa, Nepal. Clinical examination revealed fever (102.7°F), tachycardia (110 bpm), and crackles in the right lower lung field. Laboratory investigations showed anemia (Hb 8.9 g%), leukopenia (3300/cumm), elevated liver enzymes (SGPT, 117 IU/L; SGOT, 94 IU/L; ALP, 391 U/L), and elevated CRP (18.58 mg/dL). ELISA testing demonstrated concurrent positivity for Salmonella typhi IgG/IgM, scrub typhus IgM, and Brucella abortus antigens. Blood and urine cultures were negative. A…

Prevalence and zoonotic potential of pathogens in micromammals (rodents and insectivores) in the Republic of Korea.

Micromammals (rodents and insectivores), are reservoirs of numerous zoonotic pathogens and play a critical role in infectious disease transmission. The rising prevalence of micromammals-associated pathogens in the Republic of Korea highlights the urgent need for targeted surveillance. Here, we analyzed micromammal blood samples collected from 16 nationwide sites during spring 2022, autumn 2022, and spring 2023 to investigate the following key zoonotic diseases: severe fever with thrombocytopenia syndrome, Lyme disease, Q fever, scrub typhus, anaplasmosis, ehrlichiosis, and rickettsioses. Our a…

The challenges and potential solutions of achieving meaningful consent amongst research participants in northern Thailand: a qualitative study.

BACKGROUND: Achieving meaningful consent can be challenging, particularly in contexts of diminished literacy, yet is a vital part of participant protection in global health research. METHOD: We explored the challenges and potential solutions of achieving meaningful consent through a qualitative study in a predominantly hill tribe ethnic minority population in northern Thailand, a culturally distinctive population with low literacy. Semi-structured interviews were conducted with 37 respondents who had participated in scrub typhus clinical research, their family members, researchers and other k…

Not Only Leptotrombidium spp. an Annotated Checklist of Chigger Mites (Actinotrichida: Trombiculidae) Associated with Bacterial Pathogens.

Mites of the family Trombiculidae are known for playing a role in maintaining and spreading the scrub typhus etiologic agent, an intracellular Gram-negative bacterium, Orientia tsutsugamushi. Species of the genus Leptotrombidium are investigated most thoroughly, particularly in SE Asia, and a few are proven vectors for the pathogen. The mentioned association, however, is not the only one among trombiculids. Here, we present a list of chiggers indicated in the literature as positive for bacterial pathogens, tested throughout almost 100 years of research. Taxonomic identities of trombiculids fol…

Common Dermatologic Conditions in Returning Travelers.

PURPOSE OF REVIEW: Travel medicine practitioners often are confronted with returning travelers with dermatologic disorders that could be of … ropical destinations, many individuals may be exposed to rickettsia (i.e., African tick bite fever, scrub typhus, or Mediterranean spotted fever), parasitic infections (i.e., cutaneous larva migrans, cutaneous leishmaniasis, African trypanosomiasis, or American trypanosomiasis), viral infections (i.e., measles or Zika virus infection), bacterial (i.e., Buruli …

Analysis of Orientia tsutsugamushi promoter activity.

Orientia tsutsugamushi is an obligate intracellular bacterium that causes scrub typhus, a potentially fatal rickettsiosis, and for which no genetic tools exist. Critical to addressing this technical gap is to identify promoters for driving expression of antibiotic resistance and fluorescence reporter genes in O. tsutsugamushi. Such promoters would need to be highly conserved among strains, expressed throughout infection, and exhibit strong activity. We examined the untranslated regions upstream of O. tsutsugamushi genes encoding outer membrane protein A (ompA), 22-kDa type-specific antigen (ts…

CRISPR/dCas9-mediated biosensor for detection of tick-borne diseases.

Rapid and highly sensitive detection of biomolecules is greatly needed for pathogen diagnosis in clinical samples, but the method needs to b … ssed the clinical utility of this CRISPR/dCas9-mediated biosensor in tick-borne illnesses including scrub typhus (ST) and severe fever with thrombocytopenia syndrome (SFTS), whose clinical presentations are too similar to be easily differentiated. By using CRISPR/dCas9-mediated biosensor, we achieved single molecule sensitivity for the detection of ST (0.54 aM …

Erythema Nodosum Leprosum as a Rare and Challenging Cause of Pyrexia of Unknown Origin.

A 30-year old male presented with fever for last 1 year. There were associated multiple painful skin eruptions with hyperpigmentation and scaling over whole body which had been progressively increasing. He also had anasarca along with generalized weakness. He presented to us in shock after an acute episode of gastroenteritis. After stabilization, he was evaluated for cause of fever. Routine fever workup (for typhoid, syphilis, malaria, filariasis, HIV, scrub typhus, leishmaniasis) was negative. CECT chest and abdomen revealed hepatosplenomegaly. There was no response to intravenous (IV) antibi…

Survey and Phylogenetic Analysis of Rodents and Important Rodent-Borne Zoonotic Pathogens in Gedu, Bhutan.

Rodents are well-known reservoirs and vectors of many emerging and re-emerging infectious diseases, but little is known about their role in zoonotic disease transmission in Bhutan. In this study, a cross-sectional investigation of zoonotic disease pathogens in rodents was performed in Chukha district, Bhutan, where a high incidence of scrub typhus and cases of acute undifferentiated febrile illness had been reported in people during the preceding 4-6 months. Twelve rodents were trapped alive using wire-mesh traps. Following euthanasia, liver and kidney tissues were removed and tested using PCR…

Rickettsial diseases in central India: proposed clinical scoring system for early detection of spotted fever.

OBJECTIVES: To report a series of cases of rickettsial infections from central India and to develop a clinical scoring system for its early … (45.6%) were diagnosed with rickettsial diseases. 52 (69.3%) had spotted fever group and 23 (30.7%) scrub typhus. The mortality rate with rickettsial diseases was 9%. By using proposed clinical scoring system, a score of 14 has sensitivity and specificity of 96.15% and 98.84%, respectively in making a diagnosis of spotted fever group. CONCLUSION: Rickettsial …

Respiratory infections unique to Asia.

Asia is a highly heterogeneous region with vastly different cultures, social constitutions and populations affected by a wide spectrum of re … ctising respirologists in Asia. Specific infections such as melioidosis, dengue haemorrhagic fever, scrub typhus, leptospirosis, salmonellosis, penicilliosis marneffei, malaria, amoebiasis, paragonimiasis, strongyloidiasis, gnathostomiasis, trinchinellosis, schistosomiasis and echinococcosis occur commonly in Asia and manifest with a prominent respiratory comp …

Bacteriostatic and bactericidal activity of levofloxacin against Rickettsia rickettsii, Rickettsia conorii, 'Israeli spotted fever group rickettsia' and Coxiella burnetii.

Levofloxacin, the L-isomer of ofloxacin, is approximately twice as active as ofloxacin against most Gram-positive and Gram-negative bacteria … i in vitro. They are reliable alternatives to tetracycline therapy for Mediterranean spotted fever, scrub typhus and acute Q fever. Levofloxacin was bacteriostatic against R. rickettsii, R. conorii and the Israeli SFGR at concentrations of 0.5-1 mg/L, as determined by both a plaque assay and a dye uptake assay. It was also bacteriostatic against C. burnetii is …

Detection and characterization of Rickettsia tsutsugamushi (Rickettsiales: Rickettsiaceae) in infected Leptotrombidium (Leptotrombidium) fletcheri chiggers (Acari: Trombiculidae) with the polymerase chain reaction.

We developed a method for detecting and characterizing the DNA of Rickettsia tsutsugamushi in chiggers (larval trombiculid mites) by polymer … e chigger. PCR/RFLP analysis is an important new tool for investigating the complex epidemiology of scrub typhus rickettsiae in their mite vectors.

Transcriptional profiles of cytokines and chemokines reveal important pro-inflammatory response from endothelial cells during Orientia tsutsugamushi infection.

Endothelial cells (EC) are key targets during Orientia tsutsugamushi infection. Knowledge of the pro-inflammatory response against O. tsutsugamushi by ECs is limited. The aim of the present study was to characterize the pro-inflammatory transcriptional response during the first 24 h of infection of the human dermal microvascular endothelial cell line with O. tsutsugamushi Karp by examining five-time points. The transcriptional profiles of 84 genes including cytokines, chemokines, growth factors, and TNF receptor superfamily genes were studied using a RT-PCR array. We identified 40 of the 84 ge