Norovirus (NV) is a causative agent of acute gastroenteritis in humans, and shellfishes including oysters act as major vehicles of the virus. To investigate the genetic characteristics of NVs, we collected 1,512 oysters for raw consumption between October 2002 and March 2005 from two distinct areas (area A: the Sanriku Sea area; area B: the Setouchi Sea area). We detected the capsid gene and subjected it to phylogenetic analysis. By further quantification of the copy number of the genome by using real-time PCR, the NV capcid gene was detected in approximately 5% of the oysters, and they showed wide diversity. Two percent of the oysters from area B showed relatively large number of NVs, i.e., over 100 copies of capsid gene/oyster, whereas this was not observed in area A. Most of the detected NVs from oysters and humans were genetically related when the capsid region was compared. These results suggested that NVs obtained from humans and those obtained from oysters showed a potential relationship to each other and that some populations of Japanese oysters accumulated a relatively large number of NVs.
ABSTRACT. The best combination of primers and the annealing temperature of multiplex PCR for Campylobacter jejuni, Campylobacter coli, and Campylobacter lari were examined. The multiplex PCR was able to detect type strains of the three species. All results of identification of wild strains (30 strains of C. jejuni, 20 strains of C. coli, and 4 strains of C. lari) by the multiplex PCR coincided with those of the conventional biochemical identification tests, suggesting that the multiplex PCR can simultaneously differentiate C. jejuni, C. coli, and C. lari from wild strains of campylobacters easily and rapidly. Campylobacters were detected from sparrow feces by the multiplex PCR and antimicrobial sensitivities of the strains were determined to discuss the role of sparrows in contamination of broilers with C. jejuni. Three out of 13 strains of C. jejuni isolated from sparrow feces showed quinolone resistance. From the frequent use of quinolones for treatment of industrial animals like chickens, pigs, and cows, the three strains of quinolone-resistant C. jejuni in sparrows must have been originated from those industrial animals. Sparrows that have quinolone-resistant C. jejuni were considered to have contacted with industrial animals or thier feed. It may be presumed, on the contrary, that C. jejuni in sparrows could be a potential source of contamination of broilers.
Background
This study aimed to examine the prevalence, serovars, and antimicrobial resistance of
Salmonella
isolates from broiler chickens in Kagoshima, Japan. A total of 192 flocks and 3071 samples were collected from broiler chickens at local farms in Kagoshima, Japan from 2009 to 2012.
Result
Among the tested farms, 49.0% of flocks were positive for
Salmonella
, and 243 isolates were obtained from 3071 cecal samples (7.9%). All the
Salmonella
isolates were one of three serovars:
S.
Infantis (57.6%); (140/243),
S.
Manhattan (40.3%; 98/243 and
S.
Schwarzengrund (2.1%; 5/243). The proportion of
S.
Infantis isolates decreased from 66.0% in 2009 to 50.0% in 2011 but increased to 57.6% in 2012, while the proportion of
S.
Manhattan isolates significantly increased from 26.4 to 50% from 2009 to 2011, and decreased moderately to 40.9% in 2012. Most of the recovered
Salmonella
isolates were resistant to three antimicrobials, i.e., streptomycin (95.1%), sulfamethoxazole (91.0%) and oxytetracycline (91.4%). In contrast, all
Salmonella
strains were susceptible to chloramphenicol. Comparison of this study to previous studies of the antimicrobial susceptibility of
Salmonella
isolates showed that: the percentage of antibiotic-resistance isolates increased dramatically for two antibiotics, ampicillin (from 22.4 to 55.1%) and cefotaxime (from 9.1 to 52.7%). In contrast, the percentage of ofloxacin-resistant isolates decreased across the three survey periods, from 20.8% in 2004–2006 to 1.6% in the present study period (2009–2012). In addition,
S.
Infantis exhibited a variety of resistance to antimicrobials examined from sensitive to resistance to eight antimicrobials. Multidrug resistance to more than 6 six antimicrobials was detected in 113 (46.5%) of the isolates, and most of them were
S.
Manhattan.
Conclusions
There was a marked change in the serovars and antimicrobial resistance profiles of the
Salmonella
isolates in this study compared to those in previous studies. The percentage of
S.
Manhattan isolates increased as did the percentages of ampicillin- and cefotaxime-resistant isolates.
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