Isolation and whole-genome sequencing analysis of Escherichia fergusonii harboring a heat-labile enterotoxin gene from retail chicken meat in Okinawa, Japan.

This study aimed to reveal the prevalence of heat-labile enterotoxin (LT) gene-positive Escherichia fergusonii in retail chicken meat and genetically characterize these strains. E. fergusonii harboring LT gene was isolated from 6 out of 60 (10%) retail chicken samples in Okinawa, Japan. Whole-genome sequencing analysis revealed that LT gene-positive E. fergusonii from chicken meat and feces contain an IncFII plasmid harboring elt1AB, and suggested to spread clonally to retail chicken through fecal contamination. Additionally, it was found that these strains harbor multidrug-resistant genes on their plasmids. Their pathogenicity and continuous monitoring are required for confirmation.

The Spread of Heat-Labile Enterotoxin-Harboring Escherichia fergusonii in Broiler Chickens and Pigs in Okinawa, Japan.

In 2012, Escherichia fergusonii harboring a heat-labile enterotoxin (LT) was isolated from healthy chickens in South Korea. However, little is known regarding the prevalence, spread, and pathogenicity of these strains in humans and animals. This study aimed to understand the public health threats, such as the distribution, antimicrobial resistance, and genetic diversity of E. fergusonii carrying LTs. E. fergusonii containing LT was isolated from 15.0% (52/346) of chicken fecal samples from all three tested chicken farms but not from 360 pig fecal samples. The antimicrobial susceptibility testing revealed that over 75% of strains were resistant to ampicillin, kanamycin, nalidixic acid, streptomycin, or tetracycline; additionally, 71.2% (37/52) of strains were resistant to all five of these antimicrobials. The 52 strains were clustered into eight pulsed-field gel electrophoresis (PFGE) types, with types V and type VI accounting for 84.6% (44/52). In the present study, multiple chicken farms harbored E. fergusonii with similar antimicrobial resistance patterns and genetic clonality. Since the pathogenicity of LT-bearing E. fergusonii in humans and animals, such as food poisoning and sporadic diarrhea via meat, the transmission of the strains, and the dissemination of antimicrobial resistance genes are unknown, additional research is required.

Antimicrobial resistance and molecular epidemiological analysis of Escherichia fergusonii harboring the mcr gene in pigs and broiler chickens in Okinawa, Japan.

The dissemination of mcr-harboring Enterobacteriaceae, e.g., Escherichia fergusonii, with resistance to colistin via animal products is a public health concern. In our previous study, E. fergusonii harboring the mcr gene were isolated from 11 pigs and 43 chickens. To understand the spread of mcr-harboring E. fergusonii in Okinawa, Japan, and to gain further insights into how they can be controlled, an antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), a conjugation test for the transferability of mcr-harboring plasmids, and PCR-based replicon typing (PBRT) were performed using the 54 strains. According to the disk-diffusion and broth microdilution methods, 9 of the 11 strains from pigs and 9 of the 43 strains from chickens had multidrug resistance (MDR). The broth microdilution method showed that all strains were resistant to colistin, and the minimum inhibitory concentration of colistin was 4-16 µg/mL. PFGE suggested identical PFGE types were being transmitted within one pig farm, within one chicken farm, and among several chicken farms. These findings showed that some mcr-harboring E. fergusonii in Okinawa exhibited MDR, and these had spread within farms and between farms. In the mcr gene conjugation test and PBRT, a type IncI2 plasmid replicon was detected in all mcr-1-harboring transconjugants. Therefore, evidence suggests that the IncI2 plasmid is probably involved in the transmission of the mcr-1 gene. It is important to monitor the antimicrobial resistance profile and dissemination of the IncI2 plasmid in mcr-harboring E. fergusonii.

Leptospirosis with multiple organ dysfunction in a mongoose-scat-detection dog infected with Leptospira interrogans serogroup Hebdomadis, Okinawa, Japan.

A 2-year-old male mongoose-scat-detection dog was diagnosed with leptospirosis by urine PCR. The patient developed acute renal failure, hepatic dysfunction, and disseminated intravascular coagulation. Treatment with antibiotics was administered, including ampicillin and doxycycline, and supportive care management was provided. Seroconversion against serogroup Hebdomadis was observed on day 8. The leptospiral gene flaB was detected only in urine collected on day 1, from which Leptospira interrogans ST329 was identified by multilocus sequence typing using seven housekeeping genes. L. interrogans serogroup Hebdomadis ST329 has been isolated from mongooses and humans in Okinawa, Japan. This patient received early treatment with antibiotics, which may have contributed to the early recovery of renal function and removal of L. interrogans from kidney tissue.

Severe Fever with Thrombocytopenia Syndrome Virus RNA in Ticks from Wild Mongooses in Okinawa Prefecture, Japan.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic tick-borne disease caused by SFTS virus (SFTSV). SFTSV has a wide spectrum of animal hosts and is considered to circulate in an enzootic tick-vertebrate-tick cycle. A previous seroepidemiological study showed the presence of anti-SFTSV antibodies in wild mongooses (Herpestes auropunctatus) and indicated that outdoor activity was associated with an increased risk of tick bites among Okinawa residents. However, the association of SFTSV with wild mongooses and ticks remains unclear. To understand the association between ticks and mongooses with respect to the SFTSV enzootic cycle, we investigated the presence of SFTSV RNA in ticks collected from wild mongooses on the Okinawa Island. A total of 638 ticks belonging to 2 genera and 3 species (Haemaphysalis hystricis, Haemaphysalis formosensis, and Ixodes granulatus) were collected from 22 wild mongooses from 2016 to 2021. SFTSV RNA was detected in two pools of H. hystricis larvae collected from a wild mongoose in the central area of the main island of Okinawa in 2017. Although the prevalence of SFTSV in ticks from wild mongooses is low, endemic circulation of the virus in Okinawa should be carefully monitored to prevent future infections.

Characteristics of Household Transmission of COVID-19 during Its Outbreak in Okinawa, Japan from February to May 2020.

The Okinawa prefecture confirmed 142 cases of coronavirus disease from February 14 to May 2020. Among them, 78 were the first cases of a household with 174 household contacts. Of the 174 contacts, 21 contracted the disease, indicating a secondary attack rate of 12.1% (95% confidence interval [CI] 7.6-17.9%). No significant differences were observed in the demographics and quantitative reverse transcription-polymerase chain reaction test results between the first cases that became the sources of infection to the household members. The secondary attack rates with respect to the various characteristics of the household members were significantly different: aged >69 years (40.9% [95% CI 20.7-63.6%]) and those with underlying diseases (36.0% [95% CI 18.0-57.5%]). When the period from the onset to isolation of the first household case was within 3 days, the secondary attack rate was low (4.5% [95% CI 0.1-22.8%]). Among the 21 secondary cases, 11 (52.4%) developed within 5 days of symptom onset in the first case within the same household. This indicates that secondary infection within the household occurred immediately after symptom onset in the first case. Therefore, isolation of a suspected patient can help reduce secondary household infections.