Current Status of Q Fever and the Challenge of Outbreak Preparedness in Korea: One Health Approach to Zoonoses

Human Q fever, a zoonosis caused by Coxiella burnetii, presents with diverse clinical manifestations ranging from mild self-limited febrile illnesses to life-threatening complications such as endocarditis or vascular infection. Although acute Q fever is a benign illness with a low mortality rate, a large-scale outbreak of Q fever in the Netherlands led to concerns about the possibility of blood transfusion-related transmission or obstetric complications in pregnant women. Furthermore, a small minority (< 5%) of patients with asymptomatic or symptomatic infection progress to chronic Q fever. Chronic Q fever is fatal in 5–50% of patients if left untreated. In South Korea, Q fever in humans was designated as a notifiable infectious disease in 2006, and the number of Q fever cases has increased sharply since 2015. Nonetheless, it is still considered a neglected and under-recognized infectious disease. In this review, recent trends of human and animal Q fever in South Korea, and public health concerns regarding Q fever outbreaks are reviewed, and we consider how a One Health approach could be applied as a preventive measure to prepare for zoonotic Q fever outbreaks.

Pathophysiology of enteropathogenic Escherichia coli during a host infection

Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.

Molecular epidemiology of sequence type 33 of Shiga toxin-producing Escherichia coli O91:H14 isolates from human patients and retail meats in Korea

Sequence type (ST) 33 of Shiga toxin-producing Escherichia coli (STEC) strain O91:H14 has been proposed as a potential domestic clone of STEC in Korea because of its high prevalence among human patients with mild diarrhea or asymptomatic carriers. Herein, the clonal diversity of 17 STEC O91:H14 isolates of ST33 during 2003 to 2014 was analyzed by pulsed-field gel electrophoresis, including 14 isolates from human patients and 3 from retail meats. Their virulence characteristics, acid resistance, and antimicrobial susceptibility were also determined. Our results showed that all isolates were clustered mainly into three different pulsotypes and were likely low pathogenic without antimicrobial resistance.

Pathogenic and phylogenetic characteristics of non-O157 Shiga toxin-producing Escherichia coli isolates from retail meats in South Korea

Herein, we report the pathogenic and phylogenetic characteristics of seven Shiga toxin (Stx)-producing Escherichia coli (STEC) isolates from 434 retail meats collected in Korea during 2006 to 2012. The experimental analyses revealed that all isolates (i) were identified as non-O157 STEC, including O91:H14 (3 isolates), O121:H10 (2 isolates), O91:H21 (1 isolate), and O18:H20 (1 isolate), (ii) carried diverse Stx subtype genes (stx₁, stx(2c), stx(2e), or stx₁ + stx(2b)) whose expression levels varied strain by strain, and (iii) lacked the locus of enterocyte effacement (LEE) pathogenicity island, a major virulence factor of STEC, but they possessed one or more alternative virulence genes encoding cytotoxins (Cdt and SubAB) and/or adhesins (Saa, Iha, and EcpA). Notably, a significant heterogeneity in glutamate-induced acid resistance was observed among the STEC isolates (p < 0.05). In addition, phylogenetic analyses demonstrated that all three STEC O91:H14 isolates were categorized into sequence type (ST) 33, of which two beef isolates were identical in their pulsotypes. Similar results were observed with two O121:H10 pork isolates (ST641; 88.2% similarity). Interestingly, 96.0% of the 100 human STEC isolates collected in Korea during 2003 to 2014 were serotyped as O91:H14, and the ST33 lineage was confirmed in approximately 72.2% (13/18 isolates) of human STEC O91:H14 isolates from diarrheal patients.

The role of rpoS, hmp, and ssrAB in Salmonella enterica Gallinarum and evaluation of a triple-deletion mutant as a live vaccine candidate in Lohmann layer chickens

Salmonella enterica Gallinarum (SG) causes fowl typhoid (FT), a septicemic disease in avian species. We constructed deletion mutants lacking the stress sigma factor RpoS, the nitric oxide (NO)-detoxifying flavohemoglobin Hmp, and the SsrA/SsrB regulator to confirm the functions of these factors in SG. All gene products were fully functional in wild-type (WT) SG whereas mutants harboring single mutations or a combination of rpoS, hmp, and ssrAB mutations showed hypersusceptibility to H2O2, loss of NO metabolism, and absence of Salmonella pathogenicity island (SPI)-2 expression, respectively. A triple-deletion mutant, SGDelta3 (SGDeltarpoSDeltahmpDeltassrAB), was evaluated for attenuated virulence and protection efficacy in two-week-old Lohmann layer chickens. The SGDelta3 mutant did not cause any mortality after inoculation with either 1 x 10(6) or 1 x 10(8) colony-forming units (CFUs) of bacteria. Significantly lower numbers of salmonellae were recovered from the liver and spleen of chickens inoculated with the SGDelta3 mutant compared to chickens inoculated with WT SG. Vaccination with the SGDelta3 mutant conferred complete protection against challenge with virulent SG on the chickens comparable to the group vaccinated with a conventional vaccine strain, SG9R. Overall, these results indicate that SGDelta3 could be a promising candidate for a live Salmonella vaccine against FT.

Identification of Staphylococcus pseudintermedius in canine infective endocarditis using PCR-RFLP analysis / 동물의과학연구지

A 5-year-old, 8.95 kg, female Schnauzer presented anorexia with a 3-day history and increased heart sound intensity. Based on the clinical and echocardiographic findings along with the positive blood culture result, the dog was diagnosed with infective endocarditis (IE). Using proper antibiotics treatment, clinical signs were improved within 3 days and resolved within 1 week. For exact identification of the causative agent, multiplex polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) methods were performed. The etiological agent was confirmed as Staphylococcus pseudintermedius with antibiotics resistance genes such as beta-lactamase (blaZ) and methicilline resistance (mecA). The bacterial virulence factors included pyogenic toxin genes such as staphylococcal enterotoxins A, B, C, D, and E and toxic shock syndrome toxin 1. Diagnosis of IE is challenging due to a variety of non-specific clinical presentations, rapid disease progression, and lack of a confirmative diagnostic technique. This report demonstrated that such molecular diagnostics could be very useful for diagnosing and identifying characteristics of the causative organism for prediction of prognosis and proper treatment. To our knowledge, this is the first report on the isolation of S. pseudintermedius using molecular diagnostics from a clinical case of canine IE.

Antibiotic resistance and molecular characterization of ophthalmic Staphylococcus pseudintermedius isolates from dogs

The prevalence, virulence potential, and antibiotic resistance of ophthalmic Staphylococcus pseudintermedius (SP) isolated from dogs were examined. Sixty-seven Staphylococcus species were isolated from ophthalmic samples and surveyed for species-specific sequences in the Staphylococcus intermedius group (SIG) nuclease gene (SInuc), exfoliative toxin gene for SIG (siet), and antibiotic resistance genes (blaZ and mecA). PCR-restriction fragment length polymorphism analysis of the pta gene was also performed. Fifty isolates were identified as SIG strains, all of which were found to be SP. The blaZ gene was detected in 42 of the 50 SP strains and mecA gene was observed in 18 of the 50 SP strains. The 50 SP strains were most susceptible to amoxicillin/clavulanic acid (94%) and chlorampenicol (70%), and highly resistant to tetracycline (94%) and penicillin (92%). It was also found that 16 (88.9%) mecA-positive SP strains were resistant to oxacillin, tetracycline and penicillin. All mecA-positive SP were resistant to more than four of the eight tested antibiotics and therefore considered SP with multi-drug resistance (MDR). Our results indicate a high prevalence of antibiotic resistance genes in ophthalmic SP along with a close relationship between MDR SP strains and the mecA gene. Based on our findings, judicious administration of antibiotics to companion dogs is necessary.

Roles of Mesenchymal Stem Cells (MSCs) in bacterial diseases / 동물의과학연구지

Mesenchymal stem cell (MSC) based cell therapy has emerged as a promising therapeutic approach for treatment of several degenerative, infectious and non-infectious diseases. Numerous studies have demonstrated the remarkable immunosuppressive and antibacterial effects of MSCs both in vitro and in vivo, in animal models and in humans. However, the antibacterial effects of MSCs rely heavily on their paracrine factors rather than direct cell-to-cell contact and the effect is specific to disease and site of infection or injury. Furthermore, recent studies have demonstrated the double-edged sword effect of MSCs in bacterial infectious diseases. Despite their inherent potential for repair of damaged tissues, immunosuppression, and alleviation of various autoimmune as well as infectious diseases, MSCs also play a critical role in promoting persistent bacterial infection and disease progression. Therapeutic administration of MSCs successfully inhibited the bacterial growth and enhances survival by improved clearance of pathogenic bacteria in sepsis and pneumonic conditions. However, due to their abnormal transformation, they assist in long lasting survival and persistent infection of Mycobacterium tuberculosis (M. tuberculosis) and may also be responsible for progression of gastric cancer. This review focuses on recent advances that have broadened our understanding of MSC based therapy for bacterial diseases and provides new insight into the possible therapeutic targets of fatal bacterial diseases.

Dissimilarity of ccrAB gene sequences between methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus among bovine isolates in Korea

The sequences of the ccrAB genes from bovine-, canine- and chicken-originating methicillin-resistant Staphylococcus (S.) epidermidis (MRSE) and bovine methicillin-resistant Staphylococcus (S.) aureus (MRSA) were compared to investigate the frequency of intra-species horizontal transfer of the staphylococcal cassette chromosome mec (SCCmec) complex. Nineteen MRSE strains were isolated from bovine milk, chickens, and dogs, and their genetic characteristics were investigated by multilocus sequence typing and SCCmec typing. Among the animal MRSE strains, the most frequent SCCmec type was type IV, which consisted of the type B mec complex and ccrAB type 2. The ccrA2 and ccrB2 genes were sequenced from the bovine, chicken and canine MRSE strains and compared with those of the bovine MRSA strains. The sequences generally clustered as MRSA and MRSE groups, regardless of the animal source. Additionally, no bovine MRSE sequence was associated with the bovine MRSA groups. Although most of the bovine MRSE and MRSA isolates possessed SCCmec type IV sequences, our results suggest that the intra-species gene transfer of the SCCmec complex between bovine S. aureus and bovine S. epidermidis strains is not a frequent event.

Polymorphisms of interleukin-1beta promoter in simple febrile seizures / 소아과

PURPOSE: Febrile seizure (FS) is the most common type of seizure. The role of genetic factors in FSs has long been recognized. A positive family history can be elicited in 25-40% of patients with FSs; nonetheless, the genes responsible for FSs in the majority of the population remain unknown. Interleukin-1beta (IL-1beta) is a pro-inflammatory cytokine that acts as an endogenous pyrogen. Thus, IL-1beta could be involved in the pathophysiology of FSs. METHODS: To determine whether or not single nucleotide polymorphisms of the IL-1beta gene are associated with susceptibility to simple FSs, IL-1beta promoter -31 and -511 genotyping was performed by means of polymerase chain reaction-restriction fragment (PCR-RF) length polymorphism in 40 FS patients (20 sporadic and 20 familial FS patients) and 33 controls. RESULTS: There were no significant differences in the frequencies of -31 C/T and -511 C/T in the IL-1beta promoter gene, between simple FS patients and controls. CONCLUSION: The frequency of CT/CT increased relatively in familial FS patients. A study examining a larger number of FS patients is needed.

A Case of Cerebral Dystrophy and Cerebellar Atropy in Seckel Syndrome

Seckel syndrome is a rare autosomal recessive disease. The characteristic features of Seckel syndrome include Intrauterine and postnatal growth deficiency, severe microcephaly, and a bird-like head. General appearance of our patient was characterized by Pre- and postnatal growth retardation, microcephaly, large eye, and a beaked nose. The patient had mental retardation with CNS anomalies. The CNS anomalies seen in the patient included cerebral dysgenesis and cerebellar atrophy. So, we report the case of CNS anomalies in Seckel syndrome.

Phenotypic and functional analysis of bovine gammadelta lymphocytes

The studies have provided the first comprehensive comparison of the factors regulating activation and proliferation of WC1+ and WC1- gammadelta T cells. The investigation has shown that accessory molecules essential for activation and function of WC1+ and WC1- gammadelta T cells and the sources and roles of cytokines in activation of gammadelta T cells through the T cell receptor (TCR). The study has also shown that the role of cytokines in activation and function of gammadelta T cells activated indirectly through cytokines secreted by ab T cells, accessory cells and antigen presenting cells (APC). Cytokines were differentially produced by subpopulations of gammadelta T cells under different conditions of activation. The investigation obtained in this study has revealed that factors account for activation and proliferation of gammadelta T cells in cultures designed to study MHC-restricted responses to antigens. Evidence obtained here has shown there is biological relevance to activation under these culture conditions that points to potential regulatory and effector functions of gammadelta T cells. The investigations have also provided the information needed to begin identifying and characterizing antigens recognized by the TCR repertoires of WC1+ and WC1- gammadelta T cells. Finally, the investigations have provided the information needed to begin analysis of the mechanisms by which gammadelta T cells modulate MHC restricted immune responses to pathogens and derived vaccines.