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The present study aimed to investigate the incidence, virulence and antibiotic properties in Vibrio spp. isolated from cockles (Tegillarca granosa) marketed in Korea. A total of 32 Vibrio spp. isolates including V. parahaemolyticus (n = 4), V. alginolyticus (n = 11), V. diabolicus (n = 14) and V. harveyi (n = 3) were detected using gyrB sequencing. The phenotypic pathogenicity revealed that the DNase, amylase and phospholipase activities were 100%, while lipase, slime production, gelatinase and caseinase were detected in 72, 88, 88 and 81% of the isolates respectively. The PCR amplification for the detection of V. parahaemolyticus species‐specific tdh, tlh, trh and toxR genes were positive in 4 (13%), 16 (50%), 0 (0%) and 4 (13%) isolates respectively. The V. alginolytuicus species‐specific tdh, tlh, trh, toxR and vac genes were carried by 15 (47%), 29 (91%), 0 (0%), 15 (47%) and 25 (78%) of the isolates respectively. In addition, multidrug resistance was observed by 27 (84%) isolates, whereas higher resistant rates were observed against ampicillin, piperacillin, streptomycin and cephalothin. The occurrence of blaCTX (78%), blaTEM (40%), blaSHV (22%) and aac(6')‐Ib (94%) were prevalent, while strAB, tetB, aphAI‐IAB, intl1 and aadA1 gene cassettes were also detected. The results signify the potential health risks resulting from the consumption of raw cockles in Korea. Significance and Impact of the Study: Vibrios are well known to cause human infections following consumption of raw or undercooked seafood. This phenomenon has undoubtedly increased the number of health issues over the past few years in Korea. Among the identified Vibrio spp., we could detect V. diabolicus and V. harveyi for the first time in marketed cockles in Korea. The presence of species‐specific genes (tdh‐VA, tlh‐VP, tlh‐VA and toxR‐VA) in V. diabolicus exhibits the close genetic affinity among V. parahaemolyticus and V. alginolyticus. Furthermore, the prevalence of extended‐spectrum β‐lactamases (ESBLs) and other antibiotic resistance genes along with multidrug resistance signifies the potential threat for consumers. [ABSTRACT FROM AUTHOR]

The present study assessed the occurrence, virulence determinants and antimicrobial susceptibility patterns of Vibrio spp. isolated from live Manila clam (Ruditapes philippinarum). A total of 31 Vibrio spp. including 27 V. diabolicus, two V. fluvialis, one V. alginolyticus and one V. antiquarius were isolated and identified. Phenotypic detection of DNase, lipase, phospholipase, amylase and caseinase activities was 100%; and 87% gelatinase, 45% slime production and 6% haemolysin activities were also observed. The prevalence of toxin‐related virulence genes for collagenase (94%), toxR (100%), tlh (68%), and VPI (71%) was detected by PCR. Additionally, two V. fluvialis isolates carried F‐toxR and hupo genes. Moreover, 61% of the isolates showed multiple antimicrobial resistance indices >0·2. The resistance rates of ampicillin, piperacillin, colistin sulfate, rifampicin, and cephalothin were 100, 81, 71, 77 and 68% respectively. The prevalence of blaCTX‐M (87%), blaTEM (55%) and Int1 (90%) genes was observed, whereas blaSHV, strA‐strB, tetA, tetB, and aadA2 gene cassette were reported in varying combinations. However, armA, aac(3)‐IIa and quinolone resistance genes (qnrA, qnrB, qnrS) were not amplified. Thus, the virulence along with extended‐spectrum β‐lactamases (ESBLs) and other antimicrobial resistance genes in multidrug‐resistant Manila clam‐borne vibrios may pose a public health threat for consumers. Significance and Impact of the Study: In Korea, eating raw seafood is considered a great delicacy. This has negatively affected the public by increasing health issues over the years due to the ingestion of vibrios. For the first time, we could identify Vibrio diabolicus and Vibrio antiquarius in marketed Manila clams in Korea. The prevalent Vibrio diabolicus isolates demonstrated the Vibrio parahaemolyticus and Vibrio cholerae homologous virulence genes (toxR, tlh, and VPI). Additionally, the abundance of extended‐spectrum β‐lactamases (ESBLs) and integron (IntI1) harboured by Manila clam‐borne vibrios elucidate the potential health risk for consumers and may complicate health treatments in the case of infection. [ABSTRACT FROM AUTHOR]

Klebsiella sp. are responsible for a multitude of infectious diseases in both humans and animals. In this study, phylogenetic relationships, virulence and antimicrobial resistance gene properties of 16 Klebsiella sp. isolated from 49 pet turtles were investigated. The isolates including Klebsiella oxytoca (n = 13) and Klebsiella pneumoniae (n = 3) were identified using 16S rRNA gene sequencing and each species formed distinct clusters in the neighbour‐joining phylogenetic tree. The prevalence of virulence genes including ureC (100%) and kfu (68·75%) was observed among the isolates using Polymerase chain reaction (PCR) assay. The fimH, mrkD and rmpA genes were detected in all K. pneumoniae while these were absent in every K. oxytoca isolate. In antimicrobial susceptibility testing, high resistance rates were observed against ampicillin (100%) and cephalothin (62·50%). The resistance rates against imipenem, tetracycline, trimethoprim/sulfamethoxazole, nalidixic acid and ciprofloxacin were 12·50, 12·50, 12·50, 6·25 and 6·25% respectively. The presence of antimicrobial resistance genes such as plasmid‐mediated quinolone resistance (PMQR) [qnrB (37·50%), qnrA (31·25%), qnrS (12·50%) and aac(6')‐Ib‐cr (12·50%)], extended‐spectrum β‐lactamase (ESBL) [blaCTX‐M (18·75%)], β‐lactamase [blaSHV‐1 (18·75%)] and tetracycline resistance [tetE (12·50%)] was observed. The results revealed that pet turtle‐borne Klebsiella sp. may carry different types of virulence and antimicrobial resistance genes which represents a potential threat to public health. Significance and Impact of the Study: Klebsiella sp. are nonmotile Gram‐negative bacteria that are found in different environments. The virulence and antimicrobial resistance properties of pet turtle‐borne Klebsiella sp. have not been studied before. Phylogenetic relationships, virulence traits and antimicrobial resistance profiles of pet turtle‐borne Klebsiella sp. were characterized for the first time in Korea. Multiple virulence and antimicrobial resistance genes were observed among the isolates. The occurrence of virulence and antimicrobial resistance determinants in Klebsiella sp. may represent a potential threat to public health. [ABSTRACT FROM AUTHOR]

AIMS: To evaluate the electromyographic (EMG) activity of masseter and temporalis muscles in relation to impact awareness, gender, impact magnitude, and kinematics of head movement in simulated low-velocity rear-end impacts. METHODS: Twenty-nine individuals (17 men and 12 women) were subjected in random order to 3 rear-end impacts: 2 unexpected impacts (chair accelerations of 4.5 m/s2 and 10.1 m/s2) and 1 expected impact (chair acceleration of 10.1 m/s2). The EMG activity of the deep and superficial masseter muscle was recorded bilaterally. EMG activity was also recorded for the left anterior temporalis muscle. Angular acceleration and angular displacement of the head were also recorded. The temporal relationship between onset of the masticatory muscle activity and maximum peak of the kinematics of head movement was determined. RESULTS: The magnitude of normalized masticatory EMG activity ranged from 1.4 to 1.8 times higher (P < .05) for fast unexpected impacts compared to slow unexpected impacts in all masticatory muscles. The magnitude of normalized anterior temporalis EMG peak response ranged from 1.8 to 2.5 times higher (P < .05) in female subjects than in male subjects for all impacts. No significant differences were identified for impact awareness in the magnitude of normalized EMG activity for any masticatory muscle. No significant differences were identified with respect to timing of masticatory muscle response (P > .05). CONCLUSION: EMG activity increased with increased impact magnitude. Temporal and amplitude awareness of a simulated impact did not produce a difference in the masticatory muscle response. Gender differences were identified in the anterior temporalis muscle response. The onset of the masticatory muscle response occurred after peak angular acceleration of the head but prior to peak angular displacement of the head. [ABSTRACT FROM AUTHOR]

Aims: Manila clam (Ruditapes philippinarum) is one of the most popular seafood in Korea, owing to their unique taste and nutritional value. This study aimed to disclose the antibiotic and heavy metal resistance characteristics of Aeromonas spp. isolated from marketed Manila clam in Korea. Methods and results: A total of 36 Aeromonas spp. strains were isolated and subjected to two tests: an antibiotic disk diffusion test to determine their resistance to antibiotics, and a broth dilution test to determine their resistance to heavy metals. PCR‐based amplification was performed to detect the resistance genes. A high level of resistance to ampicillin (100%) and cephalothin (89%) was observed, while 42, 39, 36 and 36% of the isolates were resistant to oxytetracycline, imipenem, nalidixic acid and tetracycline respectively. In addition, among the tested heavy metals, cadmium (Cd) recorded the highest resistance rate (61%), followed by chromium (Cr) (50%), lead (Pb) (47%) and copper (Cu) (37%). However, mercury (Hg) resistance was not observed. PCRs revealed the occurrence of blaTEM, blaSHV, blaCTX‐M, qnrS, tetB, tetE, aac(6′)‐Ib, strA‐strB and intI1 genes among 100, 31, 31, 78, 78, 89, 25, 50 and 72% of the isolates respectively. Moreover, heavy metal resistance genes, copA, merA and czcA were detected in 25, 47 and 61% of the isolates respectively. Conclusions: The results suggest the importance of multi‐drug and heavy metal‐resistant aeromonads in Manila clam to assess the consumer safety and public health. Significance and Impact of the Study: This study is the first to elaborate on the importance of multi‐drug and heavy metal‐resistant aeromonads in Manila clam. Particularly, the presence of extended‐spectrum‐β‐lactamase genes and other antibiotic resistance genes intensifies the possible health risks and may complicate therapeutic treatments upon infection, while heavy metal resistance suggests possible heavy metal exposure. [ABSTRACT FROM AUTHOR]

Aims: Yesso scallop (Patinopecten yessoensis) is a popular seafood in Korea. Aeromonas spp., well‐known pathogenic bacteria, has been reported in some molluscan shellfish, but it has not been studied in scallops so far. Therefore, we aimed to isolate, identify and characterize the Aeromonas spp. isolated from marketed Yesso scallops to estimate their potential risk to public health. Methods and Results: Thirty‐two Aeromonas spp. including A. hydrophila (n = 13), A. salmonicida (n = 11), A. media (n = 3), A. caviae (n = 2), A. veronii (n = 2) and A. enteropelogenes (n = 1) were isolated from 105 marketed scallops and tested for phenotypic pathogenicity, virulence genes and antimicrobial susceptibility. Mean total bacterial count of scallop meat was 1·34 × 104 CFU per gram. Slime production and lipase tests were positive in 97% of the isolates while DNase, protease, gelatinase, phospholipase and haemolysis were shown by 88, 88, 81, 88 and 72% of the isolates respectively. Eleven virulence genes were detected among Aeromonas spp. (act (75%), alt (59%), ast (47%), aerA (78%), lip (59%), ahyB (94%), ser (75%), hlyA (75%), fla (64%), gcat (84%) and ascV (23%)), and exu was negative in all isolates. Aeromonas hydrophila and A. salmonicida harboured ≥7 virulence genes and positive for enterotoxin genes, act, alt and ast. All the isolates were multidrug resistant and 100% resistant to ampicillin, colistin, vancomycin and cephalothin. Also, 30, 31, 20, 21, 29, 24, 27 and 27 of the isolates were resistant to piperacillin, clindamycin, erythromycin, nalidixic acid, imipenem, meropenem, trimethoprim‐sulfamethoxazole and rifampicin respectively. Conclusions: It is obvious with our results that the Aeromonas spp. isolated from Yesso scallops are highly virulent and potentially pathogenic, whereas the multidrug resistance further expedite their importance. Significance and Impact of the Study: To our knowledge, this is the first study reporting Aeromonas spp. in scallop. This implies that not only the common varieties like oysters, but other bivalves can also harbour potentially pathogenic aeromonads which may have impacts on consumer health. [ABSTRACT FROM AUTHOR]

Proteeae is a tribe which consists of three genera: Proteus, Providencia and Morganella. The objective of this study was to determine antimicrobial resistance profile, virulence genotype and class 1 and 2 integrons in Proteeae isolated from pet turtles and to determine the impact of antibiotic resistance on virulence and antimicrobial resistance genes. Integron‐positive isolates were used to detect their gene cassette array. Sixty four Proteeae were isolated and all were resistant to macrolides (100%). Among 64 isolates 56, 52, 36 and 25 were resistant to nitrofurans, β‐lactams, tetracycline and aminoglycoside respectively. Sixteen (25%) isolates were positive for intI1 while 14 (21·87%) were positive for integrase 2 (intI2). Eleven (17·18%) isolates were positive for class 1 variable region while 7 (10·93%) were positive for class 2 variable region. IMP27, a novel metallo β‐lactamase gene was found in Providencia isolates. Proteus sp. were positive for every tested virulence genes and UreC gene was detected in 48·44% followed by zapA (17·19%), mrpA (17·19%) and hlyA (14·06%) genes. In this study, integron associated‐antibiotic resistance genes have been identified in Proteeae isolates in a considerable range representing clear threats to public health. Significance and Impact of the Study: In this study, multidrug‐resistant Proteeae isolates had several antibiotic resistance genes. Integrons are important contributors to the development and dissemination of antibiotic resistance. We could detect both class 1 and 2 integrons and several gene cassette arrays in class 1 integron. The gene cassette arrays of the Class 2 integrons contained IMP27‐dfrA1‐aadA1‐catB2‐ybeA‐ybgA in two isolates. To the best of our knowledge this is the first study to report detection of IMP27 in Providencia rettgeri isolates. All results indicate that healthy pet turtles act as potential reservoirs for Proteeae species with zoonotic potential. Significance and Impact of the Study: In this study, multidrug‐resistant Proteeae isolates had several antibiotic resistance genes. Integrons are important contributors to the development and dissemination of antibiotic resistance. We could detect both class 1 and 2 integrons and several gene cassette arrays in class 1 integron. The gene cassette arrays of the Class 2 integrons contained IMP27‐dfrA1‐aadA1‐catB2‐ybeA‐ybgA in two isolates. To the best of our knowledge this is the first study to report detection of IMP27 in Providencia rettgeri isolates. All results indicate that healthy pet turtles act as potential reservoirs for Proteeae species with zoonotic potential. [ABSTRACT FROM AUTHOR]

Aeromonas spp. are opportunistic pathogenic bacteria associated with a multitude of diseases in ornamental fish. In this study, virulence properties and antibiotic resistance patterns of 43 Aeromonas strains isolated from 46 zebrafish were investigated. The isolates were identified as Aeromonas veronii biovar veronii (n = 26), A. veronii biovar sobria (n = 3), Aeromonas hydrophila (n = 8), A. caviae (n = 3), Aeromonas enteropelogenes (n = 2) and Aeromonas dhakensis (n = 1) by gyrB gene sequencing. The sequence divergence within and between the species ranged from 0–5·80% and 4·90–8·00%. Each species formed a distinct group in a neighbour‐joining phylogenetic tree. The lipase production, biofilm formation, DNase activity, gelatinase production, caseinase production and β‐hemolysis were phenotypically observed in 34 (79·07%), 33 (74·74%), 30 (69·77%), 25 (58·14%), 22 (51·18%) and 21 (48·84%) isolates. The virulence genes were detected by polymerase chain reaction (PCR) in following frequencies‐ aer (86·05%), hlyA (83·72%), gcaT (83·72%), lip (72·09%), act (67·44%), fla (65·12%), ascV (58·14%), ast (55·81%), ser (41·86%), ahyB (39·53%) and alt (25·58%). Every isolate was resistant to at least four antibiotics in disk diffusion test. The multiple antibiotic resistance (MAR) index values ranged from 0·22–0·50 among the isolates. Our study suggests that zebrafish can be a potential reservoir of virulent and multi‐drug resistant Aeromonas spp. Significance and Impact of the Study: Aeromonas spp. are Gram‐negative and facultative anaerobic bacteria which are ubiquitous in aquatic environments. Virulence properties and antibiotic resistance of ornamental fish‐borne Aeromonas spp. are poorly understood. The virulence factors as well as multiple antibiotic resistance profiles of zebrafish‐borne Aeromonas spp. were characterized for the first time in Korea. Most of the isolates were positive for phenotypic virulence traits and harboured several virulence genes revealing the virulence potential of zebrafish‐borne Aeromonas spp. Additionally, the high multiple antibiotic resistance (MAR) index values displayed by the isolates highlight the necessity of responsible use of antibiotics in the ornamental fish industry. Significance and Impact of the Study: Aeromonas spp. are Gram‐negative and facultative anaerobic bacteria which are ubiquitous in aquatic environments. Virulence properties and antibiotic resistance of ornamental fish‐borne Aeromonas spp. are poorly understood. The virulence factors as well as multiple antibiotic resistance profiles of zebrafish‐borne Aeromonas spp. were characterized for the first time in Korea. Most of the isolates were positive for phenotypic virulence traits and harboured several virulence genes revealing the virulence potential of zebrafish‐borne Aeromonas spp. Additionally, the high multiple antibiotic resistance (MAR) index values displayed by the isolates highlight the necessity of responsible use of antibiotics in the ornamental fish industry. [ABSTRACT FROM AUTHOR]

Essential oils are plant extracts that have been used for their antimicrobial properties for centuries. The keeping of turtles as pets exhibits a growing trend worldwide but these animals are known to harbour a range of pathogenic bacteria. In the current study, we assessed eight essential oils as alternative antibacterial agents against nine species of pet turtle-borne Gram-negative bacteria, namely Aeromonas caviae, A. dhakensis, A. hydrophila, Citrobacter freundii, Morganella morganii, Proteus mirabilis, P. vulgaris, Pseudomonas aeruginosa and Salmonella enterica. Except for Pseudomonas aeruginosa, all other bacterial species showed high susceptibility to six essential oils, namely oregano, cinnamon, clove, lemongrass, lavender and eucalyptus oils in descending order of efficacy. Minimum inhibitory concentrations and minimum bactericidal concentrations values of the essential oils against all tested species except for P. aeruginosa showed low heterogeneity, showing that these essential oils can effectively control the growth of nearly all the tested. However, most of the tested bacteria were multiple-antibiotic-resistant as determined in the antibiotic disc diffusion test, with multiple-antibiotic-resistant index values of ≥ 0.2 for most of the strains. Therefore, with regards to their in vitro activity in controlling growth of multi-drug resistant bacteria, we can classify oregano, cinnamon, clove, lemongrass, lavender and eucalyptus essential oils as effective antibacterial agents. Thus, prospective application of these essential oils in controlling and treating these bacteria should be considered. [ABSTRACT FROM AUTHOR]

The current study was aimed to investigate the prevalence of ureC, rsbA, zapA and mrpA virulence genes using polymerase chain reaction (PCR) in Proteus spp. isolated from 5 commercially popular species of pet turtles and comparison of the mrpA gene sequences of Proteus mirabilis isolates with human clinical isolates. A total of 24 isolates in pet turtles were identified, comprised of P. mirabilis (15), Proteus vulgaris (7) and Proteus hauseri (2). The prevalence of ureC, rsbA, zapA and mrpA genes among all identified Proteus spp. isolates were 91.7%, 50%, 45.8% and 45.8%, respectively. The average percentage similarities of mrpA gene sequence of pet turtle P. mirabilis isolates to human urinary and respiratory isolates were 96.35% and 94.85%, respectively. The prevalence of virulence genes and high similarity of mrpA gene sequences between pet turtles and human P. mirabilis isolates revealed that though pet turtles are healthy, these animals may pose a potential risk of urinary and respiratory infections to humans. [ABSTRACT FROM AUTHOR]