Q fever endocarditis and new Coxiella burnetii genotype, Saudi Arabia

One health approach based descriptive study on Coxiella burnetii infections in camels and abattoir workers in the United Arab Emirates

Coxiellosis is a zoonotic bacterial disease caused by Coxiella burnetii (C. burnetii) infection that occurs as subclinical and clinical infections in animals and humans worldwide except in the Antarctica and New Zealand. The objectives of this study were to estimate the seroprevalences of C. burnetti infections in slaughtered camels and abattoir workers as well as to detect C. burnetii DNA in the clotted blood in the same study subjects at Al Bawadi abattoir of Al Ain city, in the United Arab Emirates, UAE. A cross-sectional study design was used to test 393 slaughtered camels and 86 abattoir workers for C. burnetii antibodies between March 2022 and July 2023 using enzyme-linked immunosorbent assay (ELISA) kits supplied by ID Vet multispecies and Abbexa, respectively. Besides, real-time polymerase chain reaction (qPCR) was used for the detection of C. burnetti DNA in clotted blood of 366 camels and 86 abattoir workers. The seroprevalences of C. burnetii infection were 52.9% (95% confidence interval, CI: 46.0, 60.6%) and 24.4% (95% CI: 15.1, 37.3%) in camels and abattoir workers. But, C. burnetii DNA was not detected in clotted blood samples of camels and abattoir workers. Sex, age and body condition of the camels were not associated with the seroprevalence of C. burnetii while abattoir workers of African origin were more likely to be seropositive (odds ratio, OR = 3.70; 95% CI: 1.05, 13.60) than abattoir workers of south Asian origin. The seroprevalences of C. burnetii infections were high in both slaughtered camels and abattoir workers although its DNA was not detected in the clotted blood of either of the study subjects.

Genetic diversity of wild rodents and detection of Coxiella burnetii, the causative agent of Q fever, in Saudi Arabia

Throughout history, wildlife has been regarded as a major source of infectious diseases. Rodentia, the most speciose order of mammals, whose members are recognised hosts of more than 60 zoonotic diseases, represent a potential threat to human health. Recently, epidemiological data from Saudi Arabia indicated an actual growth in the number of emerging and/or re-emerging cases of several zoonoses. However, there is a lack of studies focusing on the molecular taxonomy of rodents and the pathogens they may harbour in this region. In this study, the first molecular characterisation of six rodent taxa in this region is provided, based on partial Cyt B and 16S genes. The data confirm the spread of rodent-associated C. burnetii strains in Jazan, southwestern Saudi Arabia. The PCR targeting IS111, the multi-copy transposase gene, revealed 17.5% (36/205) positive samples, whereas the second nested PCR, targeting the single-copy Com1 gene, revealed 16.6% (34/205) positive samples. Phylogenetic and network analyses indicated the presence of four haplotypes of C. burnetii within the studied localities. One major haplotype (H-2) was observed in all rodent species and from 18 localities. The infection rates of C. burnetii among studied species, localities and habitats were not significantly different (>0.05). Our results facilitate the assessment of the health risk associated with rodents and the development of strategies to control the increasing impacts of Q fever.

Multiyear prospective cohort study to evaluate the risk potential of MERS-CoV infection among Malaysian Hajj pilgrims (MERCURIAL): a study protocol

INTRODUCTION

Middle East respiratory syndrome (MERS) is a viral respiratory infection caused by the MERS-CoV. MERS was first reported in the Kingdom of Saudi Arabia in 2012. Every year, the Hajj pilgrimage to Mecca attracts more than two million pilgrims from 184 countries, making it one of the largest annual religious mass gatherings (MGs) worldwide. MGs in confined areas with a high number of pilgrims' movements worldwide continues to elicit significant global public health concerns. MERCURIAL was designed by adopting a seroconversion surveillance approach to provide multiyear evidence of MG-associated MERS-CoV seroconversion among the Malaysian Hajj pilgrims.

METHODS AND ANALYSIS

MERCURIAL is an ongoing multiyear prospective cohort study. Every year, for the next 5 years, a cohort of 1000 Hajj pilgrims was enrolled beginning in the 2016 Hajj pilgrimage season. Pre-Hajj and post-Hajj serum samples were obtained and serologically analysed for evidence of MERS-CoV seroconversion. Sociodemographic data, underlying medical conditions, symptoms experienced during Hajj pilgrimage, and exposure to camel and untreated camel products were recorded using structured pre-Hajj and post-Hajj questionnaires. The possible risk factors associated with the seroconversion data were analysed using univariate and multivariate logistic regression. The primary outcome of this study is to better enhance our understanding of the potential threat of MERS-CoV spreading through MG beyond the Middle East.

ETHICS AND DISSEMINATION

This study has obtained ethical approval from the Medical Research and Ethics Committee (MREC), Ministry of Health Malaysia. Results from the study will be submitted for publication in peer-reviewed journals and presented in conferences and scientific meetings.

TRIAL REGISTRATION NUMBER

NMRR-15-1640-25391.

Seroprevalence and risk factors of Q-fever (C. burnetii infection) among ruminants reared in the eastern region of the Kingdom of Saudi Arabia

Q-fever is a worldwide spread zoonotic disease associated with severe illness in humans and abortions and stillbirths in ruminants. Ruminants are major sources of human infection where subclinical carriers shed the bacteria in various secretions and excreta. The goal of the current study was to investigate the prevalence and risk factors of Coxiella burnetii infection among cattle, sheep, and goats in the eastern province of the Kingdom of Saudi Arabia (KSA). A total of 1310 serum samples were collected through a designed cross-sectional study from private farms and slaughterhouses in the study area and examined against antibodies of C. burnetii using ELISA. A multivariate logistic regression analysis was built to detect risk factors of C. burnetii infection among examined species. The prevalence of C. burnetii infection among examined animals was 9.2% (CI, 7.7-10.8)-15.6%, 9.1%, and 5.8% among goats, cattle, and sheep, respectively). The risk of getting C. burnetii infection among old animals (> 1 year old) was 23 times higher than the risk among young animals (< 1 year old) (95% CI, 10.04-53.01; P < 0.01). Goats were 2.27 (95% CI, 1.41-3.66; P < 0.01) and 3 times at higher risk than cattle and sheep, respectively, of getting C. burnetii infection. In conclusion, C. burnetii infection is widespread among different ruminant species of the eastern province of KSA which represents a high risk for environmental contamination and disseminating the infection to humans and animal species in that area. Also, our findings may reflect the disease status in other countries of the Arabian Gulf area.

Q-fever prosthetic valve endocarditis in a patient with SLE and antiphospholipid antibody syndrome

Q fever prosthetic valve endocarditis in association with antiphospholipid antibody syndrome (APS) in systemic lupus erythematosus (SLE) has not been previously reported. Here, we report a 22-year-old Saudi female diagnosed with SLE and APS. She had mitral valve replacement with bio-prosthesis five years earlier for Libman-Sack endocarditis. She presented with two months' history of fever, cough, palpitations, and progressive shortness of breath. A transthoracic echocardiogram showed a degenerative mitral valve prosthesis with a large mass causing severe obstruction. Open heart surgery revealed multiple masses on the mitral valve. PCR from the resected tissues was positive for Coxiella burnetii DNA. Q fever serology showed phase two IgG 1:2048, phase one IgG 1:512, and IgM 1:1024. The valve was replaced with a bio-prosthesis. She was well at 12 months of follow-up.

Molecular typing of Coxiella burnetii from sheep in Egypt

Coxiella burnetii, the etiological agent of Q fever, is a globally distributed zoonotic disease. The disease was reported serologically in different animal species and humans in Egypt but the genetic information about circulating Coxiella strains is limited. The present study aimed to genetically characterize Coxiella positive samples, identified in abortive sheep, based on a 17-loci Multiple Locus Variable number tandem repeat analysis (MLVA) panel and Multispacer Sequence Typing (MST). Four MLVA types were found among six examined samples. While all three samples examined by MST were identified as novel sequence type (ST) closely related to human heart valve isolates from France, Saudi Arabia, USA and United Kingdom. This study provides the first genetic information about circulating Coxiella strains in Egypt and improves epidemiological data of Q fever in the country.

Ten-year experience of Q fever endocarditis in a tertiary cardiac center in Saudi Arabia

BACKGROUND

Q fever endocarditis (QFE) is considered rare in the Middle East, with only a few cases reported in Saudi Arabia. The aim of this study is to report on the experience of our centre on QFE.

METHODS

We searched the medical records for cases of QFE at our cardiac center from 2009-2018. Demographic data, clinical features, serology and echocardiography results, treatments, and outcomes were assessed.

RESULTS

Five hundred and two cases of infective endocarditis were detected over the 10 years period. Among the 234 patients with blood culture-negative endocarditis (BCNE), 19 (8.10%) had QFE. All patients had a previously diagnosed congenital heart disease except for one patient with rheumatic heart disease. Eleven patients had received a bovine jugular vein-related implant, e.g., a Melody valve (seven patients) or Contegra conduit (four patients). Coinfection was detected in three patients, and immunologic and embolic phenomena were observed in five patients. All patients received a combination of hydroxychloroquine and doxycycline, with good outcomes. Only two patients required surgery while on treatment. Two patients died several months after treatment; the cause of death was not identified.

CONCLUSION

This study indicates that Q fever exists in our population. The majority of the patients had congenital heart disease (CHD) and underwent bovine jugular vein implants. Patients with CHD are at increased risk of infective endocarditis. Bovine jugular vein implants increase the risk of infective and possibly QFE. Proper exclusion of Q fever is warranted in all BCNE and possibly in culture-positive endocarditis cases in areas endemic to Q fever.

KEY POINTS

We presented the largest series of Q fever endocarditis cases in Saudi Arabia. We showed that Q fever is not rare in the Middle East and suggest that it should be considered in all blood culture-negative endocarditis cases.

Extensive genome analysis of Coxiella burnetii reveals limited evolution within genomic groups

BACKGROUND

Coxiella burnetii is a zoonotic pathogen that resides in wild and domesticated animals across the globe and causes a febrile illness, Q fever, in humans. An improved understanding of the genetic diversity of C. burnetii is essential for the development of diagnostics, vaccines and therapeutics, but genotyping data is lacking from many parts of the world. Sporadic outbreaks of Q fever have occurred in the United Kingdom, but the local genetic make-up of C. burnetii has not been studied in detail.

RESULTS

Here, we report whole genome data for nine C. burnetii sequences obtained in the UK. All four genomes of C. burnetii from cattle, as well as one sheep sample, belonged to Multi-spacer sequence type (MST) 20, whereas the goat samples were MST33 (three genomes) and MST32 (one genome), two genotypes that have not been described to be present in the UK to date. We established the phylogenetic relationship between the UK genomes and 67 publically available genomes based on single nucleotide polymorphisms (SNPs) in the core genome, which confirmed tight clustering of strains within genomic groups, but also indicated that sub-groups exist within those groups. Variation is mainly achieved through SNPs, many of which are non-synonymous, thereby confirming that evolution of C. burnetii is based on modification of existing genes. Finally, we discovered genomic-group specific genome content, which supports a model of clonal expansion of previously established genotypes, with large scale dissemination of some of these genotypes across continents being observed.

CONCLUSIONS

The genetic make-up of C. burnetii in the UK is similar to the one in neighboring European countries. As a species, C. burnetii has been considered a clonal pathogen with low genetic diversity at the nucleotide level. Here, we present evidence for significant variation at the protein level between isolates of different genomic groups, which mainly affects secreted and membrane-associated proteins. Our results thereby increase our understanding of the global genetic diversity of C. burnetii and provide new insights into the evolution of this emerging zoonotic pathogen.

From Q Fever to Coxiella burnetii Infection: a Paradigm Change

Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.

Coxiella burnetii Endocarditis in a Child Caused by a New Genotype

Coxiella burnetii endocarditis is a rare diagnosis in children. We present a case of Q fever endocarditis due to a new genotype, MST 54, and review recent literature on Q fever infections in children. Practitioners should consider Q fever in culture-negative endocarditis, particularly in children with congenital heart disease and history of travel or residence in endemic regions.

The contribution of genomics to the study of Q fever

Coxiella burnetii is the etiological agent of Q fever, a worldwide zoonosis that can result in large outbreaks. The birth of genomics and sequencing of C. burnetii strains has revolutionized many fields of study of this infection. Accurate genotyping methods and comparative genomic analysis have enabled description of the diversity of strains around the world and their link with pathogenicity. Genomics has also permitted the development of qPCR tools and axenic culture medium, facilitating the diagnosis of Q fever. Moreover, several pathophysiological mechanisms can now be predicted and therapeutic strategies can be determined thanks to in silico genome analysis. An extensive pan-genomic analysis will allow for a comprehensive view of the clonal diversity of C. burnetii and its link with virulence.

Draft Genome Sequence of Coxiella burnetii Strain Cb196, an Agent of Endocarditis in Saudi Arabia

Coxiella burnetii Cb196, with a 2,006,415-bp genome, is a strain isolated from a 45-year-old man in Saudi Arabia with endocarditis. It belongs to the genotype MST51, which was detected for the first time only in this country. Cb196 shows more similarity to C. burnetii CbuK_Q154, belonging to genotype 8, which was phylogenetically close to MST51.

Identification of novel Coxiella burnetii genotypes from Ethiopian ticks

Background

Coxiella burnetii, the etiologic agent of Q fever, is a highly infectious zoonotic bacterium. Genetic information about the strains of this worldwide distributed agent circulating on the African continent is limited. The aim of the present study was the genetic characterization of C. burnetii DNA samples detected in ticks collected from Ethiopian cattle and their comparison with other genotypes found previously in other parts of the world.

Methodology/Principal Findings

A total of 296 tick samples were screened by real-time PCR targeting the IS1111 region of C. burnetii genome and from the 32 positive samples, 8 cases with sufficient C. burnetii DNA load (Amblyomma cohaerens, n = 6; A. variegatum, n = 2) were characterized by multispacer sequence typing (MST) and multiple-locus variable-number tandem repeat analysis (MLVA). One novel sequence type (ST), the proposed ST52, was identified by MST. The MLVA-6 discriminated the proposed ST52 into two newly identified MLVA genotypes: type 24 or AH was detected in both Amblyomma species while type 26 or AI was found only in A. cohaerens.

Conclusions/Significance

Both the MST and MLVA genotypes of the present work are closely related to previously described genotypes found primarily in cattle samples from different parts of the globe. This finding is congruent with the source hosts of the analyzed Ethiopian ticks, as these were also collected from cattle. The present study provides genotype information of C. burnetii from this seldom studied East-African region as well as further evidence for the presumed host-specific adaptation of this agent.

Coxiella burnetii-positive PCR in febrile patients in rural and urban Africa

OBJECTIVES

Q fever has been reported throughout the African continent. The objective of this study was to detect the presence of Coxiella burnetii in febrile patients from Africa.

METHODS

Blood samples from febrile and non-febrile patients from six African countries and from France were investigated retrospectively for Q fever infection by molecular assays targeting the IS1111 and IS30A spacers.

RESULTS

We tested 1888 febrile patients from Senegal, Mali, Tunisia, Algeria, Gabon, and Morocco and found one male adult patient (0.3%) infected with C. burnetii in Algeria and six positive patients (0.5%) in Senegal. For one patient from Senegal we determined that the infection was caused by C. burnetii genotype 35. In Senegal, more patients were infected with C. burnetii in Keur Momar Sarr (p=0.002) than in the other locations. Blood samples taken from 500 (51% males) non-febrile people from Senegal and France were all negative.

CONCLUSIONS

The installation of point-of-care laboratories in rural Africa can be a very effective tool for studying the epidemiology of many infectious diseases.