RESUMEN
Colistin is considered the last resort for treating infections caused by multidrug-resistant bacteria. However, the spread of the plasmid-borne colistin-resistance gene mcr-1 has become a public health threat. In this study, we identified mcr-1-harboring Leclercia adecarboxylata strain (WWCOL-134) isolated from wastewater in Seoul. The strain had a colistin MIC value of 2 µg/ml and was resistant to cefotaxime, gentamicin, tetracycline, trimethoprim, and sulfamethoxazole. The mcr-1 gene, along with an array of resistance genes, was located on a 236-kb plasmid (pCOL134-1), which contained the typical IncHI2 backbone of reported mcr-1-carrying plasmids, and was transferred to an Escherichia coli strain by conjugation. To the best of our knowledge, this is the first study to report the emergence of mcr-1-harboring Leclercia sp. isolate. Our findings demonstrate the ongoing spread of colistin resistance among Enterobacterales species, emphasizing the need for surveillance of antimicrobial resistance in wastewater environments.
RESUMEN
BACKGROUND: Rotavirus group A (RVA) is a causative agent of acute gastroenteritis among young children worldwide, despite the global expansion of rotavirus vaccination. In Korea, although the prevalence of RVA has been reduced among young children owing to vaccination, nosocomial infections still occur among neonates. OBJECTIVES: The aim of this study was to investigate the molecular epidemiology of RVA strains associated with several neonatal outbreaks in Seoul from 2017 to 2020. STUDY DESIGN: Clinical and environmental samples were collected and screened for the presence of RVA using ELISA and PCR targeting VP6, respectively. RVA-positive strains were genotyped via RT-PCR and subsequent sequencing of VP4 and VP7 and were phylogenetically compared with RVA strains from other countries. RESULTS: During 2017-2020, a total of 15 RVA outbreaks occurred at neonatal facilities (six in hospital neonatal wards and nine in postpartum care centers) in Seoul, and only two RVA genotypes were detected: G4P[6] and G8P[6]. G8P[6] emerged in Seoul November 2018 and immediately became the predominant genotype among neonates, at least up to 2020. Phylogenetic analysis revealed that the G8P[6] genotype in this study was closely related to G8P[6] strains first identified in Korea in 2017, but differed from G8P[6] strains detected in Africa. CONCLUSIONS: A novel G8P[6] genotype of RVA strains has emerged and caused outbreaks among neonates in Seoul. Continued surveillance for circulating RVA genotypes is imperative to monitor genotype changes and their potential risks to public health.
Asunto(s)
Infección Hospitalaria , Brotes de Enfermedades , Epidemiología Molecular , Filogenia , Infecciones por Rotavirus , Rotavirus , Femenino , Humanos , Recién Nacido , Heces/virología , Genotipo , Rotavirus/genética , Infecciones por Rotavirus/epidemiología , Infecciones por Rotavirus/virología , Seúl/epidemiología , Infección Hospitalaria/epidemiología , Infección Hospitalaria/virología , Proteínas de la Cápside/genética , Microbiología Ambiental , MasculinoRESUMEN
The bacterial genus Enterococcus encompasses 38 species. Two of the most common species are E. faecalis and E. faecium. Recently, however, there has been an increase in clinical reports concerning less prevalent Enterococcus species, such as E. durans, E. hirae, and E. gallinarum. Rapid and accurate laboratory methods are needed to facilitate the identification of all these bacterial species. In the present study, we compared the relative accuracy of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS), VITEK 2, and 16S rRNA gene sequencing using 39 enterococci isolates from dairy samples, and compared the resultant phylogenetic trees. We found that MALDI-TOF MS correctly identified all isolates at the species level except for one, whereas the VITEK 2 system, which is an automated identification system using biochemical characteristics of species, misidentified ten isolates. However, phylogenetic trees constructed from both methods showed all isolates in similar positions. Our results clearly showed that MALDI-TOF MS is a reliable and rapid tool for identifying Enterococcus species with greater discriminatory power than the biochemical assay method of VITEK 2.
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Vibrio parahaemolyticus is a marine bacterium that causes foodborne diarrhea. Many seafood restaurants keep live fish and shellfish in fish tanks for use in raw seafood dishes; thus, the present study aimed to investigate the prevalence, antibiotic-resistance, and virulence characteristics exhibited by V. parahaemolyticus detected in restaurant fish-tank water samples collected in Seoul, South Korea. Fish-tank water samples were collected from 69 restaurants in Seoul, and screened for the presence of V. parahaemolyticus via both a commercial detection kit, and a real-time polymerase chain reaction (RT-PCR) to detect the toxR gene. Antibiotic susceptibility and virulence determinants of V. parahaemolyticus isolates were evaluated and identified using standard disk-diffusion and RT-PCR methods, respectively. Thirty-five (50.7%) of the 69 analyzed water samples were found to be contaminated with V. parahaemolyticus. Those isolates were most often resistant to ampicillin (51.4% of isolates), followed by amikacin and tetracycline (11.4%), and ceftazidime (8.6%). Thirty (85.7%) out of the 35 isolates carried all four cytotoxicity-inducing type III secretion system 1 (T3SS1) genes [specifically, 34 (97.1%), 33 (94.3%), 35 (100%), and 32 (91.4%) isolates carried genes encoding the VP1670, VP1686, VP1689, and VP1694 T3SS1 proteins, respectively]. The type VI secretion systems (T6SS1 and T6SS2) genes were also detected in 11 (31.4%) and 27 (77.1%) isolates, respectively. However, virulence determinants such as the hemolysin (tdh and trh), urease (ureC), T3SS2α, or T3SS2ß genes that are known to be associated with enterotoxicity were not detected in all isolates. Although some known major virulence genes were not detected in the V. parahaemolyticus isolates, the results of this study indicate that restaurant fish tanks are a potential source of antibiotic-resistant V. parahaemolyticus. The presented data support the need for strict guidelines to regulate the maintenance of restaurant fish tanks to prevent antibiotic-resistant foodborne vibriosis.
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Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Agua de Mar/microbiología , Vibrio parahaemolyticus/efectos de los fármacos , Factores de Virulencia/genética , Proteínas Bacterianas/genética , ADN Bacteriano , Proteínas de Unión al ADN/genética , Contaminación de Alimentos , Prevalencia , Reacción en Cadena en Tiempo Real de la Polimerasa , Restaurantes , Alimentos Marinos/microbiología , Seúl , Factores de Transcripción/genética , Vibrio parahaemolyticus/clasificación , Vibrio parahaemolyticus/aislamiento & purificación , VirulenciaRESUMEN
The possible transport of pathogenic microorganisms during Asian dust events could be an important concern for health workers; however, this is still uncertain owing to a lack of supporting evidence. The present study aimed to investigate the presence of pathogenic microorganisms in air samples collected during the Asian and non-Asian dust periods. Between March and September 2016, air samples were collected at three weather observation stations in Seoul using a high-volume air sampler. Multiplex PCR was performed using the Allplex™ respiratory and gastrointestinal panel assay kits to detect 46 microorganisms. RT-PCR was performed for klassevirus, Aichivirus, and human parechovirus (HPeV) detection. In total, 71 air samples were collected during the Asian (8 samples) and non-Asian (63 samples) dust events. During an Asian dust event, only one human rhinovirus (HRV)-positive air sample was collected on April 23. During the non-Asian dust period, HRV, HPeV, norovirus (NoV), enteroaggregative Escherichia coli (EAEC), enterotoxigenic E. coli (ETEC), and Blastocystis hominis were detected in four, two, one, one, one, and one air samples, respectively. Pathogenic viruses were mostly detected in ambient air samples during the non-Asian dust period, which suggests a possible air-borne transmission of viral pathogens; however, the role of Asian dust in epidemics caused by pathogenic viruses is unclear.