scholarly journals Occurrence and Characterization of Salmonella Isolated from Large-Scale Breeder Farms in Shandong Province, China

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jie Yang ◽  
Siwei Gao ◽  
Yajie Chang ◽  
Mingliu Su ◽  
Yutong Xie ◽  
...  

This study aimed to investigate the prevalence and antimicrobial resistance of Salmonella spp. isolated from large-scale breeder farms in Shandong Province, China. A total of 63 Salmonella isolates (63/409, 15.4%) were identified from 409 samples collected from five large-scale breeder farms in Shandong Province. These Salmonella isolates were assayed for serotype, antimicrobial susceptibility, prevalence of class 1 integrons, quinolone resistance genes, and β-lactamase genes and subtyped by multilocus sequence typing (MLST). Among these isolates, S. Enteritidis (100%) was the predominant serovar, and high antimicrobial resistance rates to nalidixic acid (100.0%), streptomycin (100.0%), ampicillin (98.4%), and erythromycin (93.7%) were observed. All of the isolates carried blaTEM. MLST results showed that only one sequence type (ST11) was identified. Our findings indicated that Salmonella was generally prevalent not only on broiler farms but also on breeder farms.

Author(s):  
Jiangqing Huang ◽  
Fangjun Lan ◽  
Yanfang Lu ◽  
Bin Li

Background. Escherichia coli sequence type 131 (ST131) is an important multidrug-resistant extraintestinal pathogen, which can cause many kinds of infections. Integrons may play a crucial role in the dissemination of antibiotic resistance genes. The purpose of this study was to characterize the prevelance of integrons among E. coli ST131 strains in China. Methods. Eighty-three E. coli ST131 isolates were used in this study. The antibiotic susceptibility test was performed by the disk diffusion method. The presence and characterization of class 1, 2, and 3 integrons, as well as promotor of gene cassettes and other antimicrobial resistance genes, were detected by PCR and DNA sequencing. Transfer of integrons was carried out using a broth culture mating method. Clonal relatedness of E. coli ST131 isolates was analyzed by PFGE. Results. Overall, 26.5% (22/83) of the E. coli ST131 isolates carried class 1 integrons. Class 2 and 3 integrons were not found in this study. Two types of gene cassette arrays were demonstrated in this study and were as follows: dfrA17-aadA5 and aac(6′)-Ib-cr-cmlA5. Only one type of Pc promoter variant was detected among 22 integron-positive isolates (PcW). In vivo transfer of integron was successful for 9 of integron-positive E. coli ST131 isolates harboring resistance gene cassettes. Results of PFGE demonstrated that the integron-positive E. coli ST131 isolates were grouped into 12 different PFGE clusters. Conclusions. Our study showed a low prevalence of integrons was detected in E. coli ST131. Continued surveillance of this mobile genetic element should be performed to study the evolution of antibiotic resistance among E. coli ST131.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Liting Wu ◽  
Hongduo Bao ◽  
Zhengquan Yang ◽  
Tao He ◽  
Yuan Tian ◽  
...  

Abstract Background Listeria monocytogenes is one of the deadliest foodborne pathogens. The bacterium can tolerate severe environments through biofilm formation and antimicrobial resistance. This study aimed to investigate the antimicrobial susceptibility, resistance genes, virulence, and molecular epidemiology about Listeria from meat processing environments. Methods This study evaluated the antibiotic resistance and virulence of Listeria isolates from slaughtering and processing plants. All isolates were subjected to antimicrobial susceptibility testing using a standard microbroth dilution method. The harboring of resistant genes was identified by polymerase chain reaction. The multilocus sequence typing was used to determine the subtyping of the isolates and characterize possible routes of contamination from meat processing environments. The virulence of different STs of L. monocytogenes isolates was evaluated using a Caco-2 cell invasion assay. Results A total of 59 Listeria isolates were identified from 320 samples, including 37 L. monocytogenes isolates (62.71%). This study evaluated the virulence of L. monocytogenes and the antibiotic resistance of Listeria isolates from slaughtering and processing plants. The susceptibility of these 59 isolates against 8 antibiotics was analyzed, and the resistance levels to ceftazidime, ciprofloxacin, and lincomycin were as high as 98.31% (L. m 37; L. innocua 7; L. welshimeri 14), 96.61% (L. m 36; L. innocua 7; L. welshimeri 14), and 93.22% (L. m 35; L. innocua 7; L. welshimeri 13), respectively. More than 90% of the isolates were resistant to three to six antibiotics, indicating that Listeria isolated from meat processing environments had high antimicrobial resistance. Up to 60% of the isolates harbored the tetracycline-resistance genes tetA and tetM. The frequency of ermA, ermB, ermC, and aac(6′)-Ib was 16.95, 13.56, 15.25, and 6.78%, respectively. Notably, the resistant phenotype and genotype did not match exactly, suggesting that the mechanisms of antibiotic resistance of these isolates were likely related to the processing environment. Multilocus sequence typing (MLST) revealed that 59 Listeria isolates were grouped into 10 sequence types (STs). The dominant L. monocytogenes STs were ST5, ST9, and ST121 in the slaughtering and processing plant of Jiangsu province. Moreover, ST5 subtypes exhibited high invasion in Caco-2 cells compared with ST9 and ST121 cells. Conclusion The dominant L. monocytogenes ST5 persisted in the slaughtering and processing plant and had high antimicrobial resistance and invasion characteristics, illustrating a potential risk in food safety and human health.


2021 ◽  
Author(s):  
Liting Wu ◽  
Hongduo Bao ◽  
Zhengquan Yang ◽  
Tao He ◽  
Yuan Tian ◽  
...  

Abstract Background: Listeria monocytogenes is one of the deadliest foodborne pathogens, and the bacterium can tolerate severe environments through biofilm formation and antimicrobial resistance. The objective of this study was to investigate the antimicrobial susceptibility, resistance genes,virulence and molecular epidemiology about Listeria from meat processing environments. Methods: This study evaluated the antibiotic resistance and virulence of Listeria isolates from slaughtering and processing plants. All isolates were subjected to antimicrobial susceptibility testing by using a standard microbroth dilution method. The carrying of resistant genes were identified by Polymerase Chain Reaction (PCR). The multilocus sequence typing (MLST) was determined subtyping of the isolates and to characterize possible routes of contamination from meat processing environments. The virulence of different STs of L. monocytogenes isolates were evaluated by Caco-2 cells invasion assay. Results: A total of 59 Listeria isolates were identified from 320 samples, including 37 L. monocytogenes (62.71%). This study evaluated the virulence of L. monocytogenes and antibiotic resistance of Listeria isolates from slaughtering and processing plants. The susceptibility of these 59 isolates against eight antibiotics was analyzed, and the resistance levels to ceftazidime, ciprofloxacin, and lincomycin were as high as 98.31% (L. m 37; L. innocua 7; L. welshimeri 14), 96.61% (L. m 36; L. innocua 7; L. welshimeri 14), and 93.22% (L. m 35; L. innocua 7; L. welshimeri 13) respectively. Over 90% of the isolates were resistant to 3-6 antibiotics, indicating that Listeria isolated from meat processing environments has high antimicrobial resistance. Up to 60% of the isolates carried the tetracycline-resistance genes tetA and tetM. The frequencies of ermA, ermB, ermC, and aac(6’)-Ib were 16.95%, 13.56%, 15.25%, and 6.78%, respectively. Notably, the resistant phenotype and genotype did not match exactly, suggesting that the mechanisms of antibiotic resistance of these isolates were likely related to the processing environment. Multilocus sequence typing (MLST) revealed that 59 Listeria isolates were grouped into 10 sequence types (STs). The dominant L. monocytogenes STs were ST5, ST9, and ST121 in the slaughtering and processing plant of Jiangsu province. Moreover, ST5 subtypes exhibited high invasion in Caco-2 cells compared with ST9 and ST121. Conclusions: The results of this study predict a prevalence of Listeria contamination in the slaughtering and processing plant , and resistance of the ST5 subtypes isolates to the antimicrobials may cause potential public health risks.


Author(s):  
Xiaonan Zhao ◽  
Ming Hu ◽  
Qing Zhang ◽  
Cui Zhao ◽  
Yin Zhang ◽  
...  

Abstract Background Salmonella spp. are one of the most important foodborne bacterial pathogens in human beings and animals. The prevalence of Salmonella from broilers in Shandong, China and antimicrobial susceptibility of these isolates was determined. Results From May to October 2018, 600 samples collected, 67 Salmonella isolates were recovered with an isolation rate of 11.2%. The most common serovars were S. enteritidis and S. typhimurium. The highest incidence of resistance observed were for PB (100%), and AMP (68.7%), and the MDR Salmonella isolate rate was 53.7%. Four β-lactamase genes were detected among the isolates, all the isolates carried bla TEM (67/67, 100%), followed by bla OXA (19/67, 28.4%), bla CTX-M (17/67, 25.4%), and bla PSE (7/67, 10.4%); four plasmid-mediated quinolone resistance genes were detected among the isolates, the prevalent resistance genes was aac(6’)-Ib-cr (18/67, 26.9%), followed by oqxB (9/67, 13.4%), qnrB (6/67, 9.0%), and qnrD (1/67, 1.5%); the prevalent rate of mcr -1 was 6.0%(4/67). Class 1 integrons were detected in 26.9% of these isolates and contained seven groups of resistance gene cassettes. MLST analysis revealed seven sequence types, and ST11 was the most frequent sequence types. Conclusions This study indicated that reduction of Salmonella and strict control on the use of antibiotics in more than 5000 million broilers in Shandong are the vitally important measure to keep public health.


2012 ◽  
Vol 75 (8) ◽  
pp. 1486-1491 ◽  
Author(s):  
MUEEN ASLAM ◽  
MOUSSA S. DIARRA ◽  
LUKE MASSON

The objective of this study was to assess the antimicrobial resistance and virulence genotypes of Enterococcus faecalis isolated from samples obtained from a commercial pork processing plant. A total of 200 samples were randomly obtained from carcasses after bleeding (BC; 50 samples) and pasteurization (PC; 100 samples) and from retail pork products (RP; 50 samples). One isolate from each E. faecalis–positive sample was analyzed for antimicrobial susceptibility and characterized using a enterococcal microarray for analysis of resistance and virulence genes. E. faecalis was isolated from 79.5% of BC samples, 2% of PC samples, and 72.7% of RP samples. Resistance to the clinically important drugs ciprofloxacin (one isolate each from BC and RP samples) and daptomycin (one isolate each from PC and RP samples) was found. Multiresistance (to five or more antimicrobials) was more common in E. faecalis isolates from BC (77.4% of isolates) samples than those from PC (25%) and RP (37.6%) samples. Resistance to kanamycin (43.5%) and streptomycin (69.2%) was noted mostly in E. faecalis from BC samples. The most common resistance genes (>5% prevalence) found in E. faecalis were those for aminoglycosides (aac(6), aphA3, and aadE), macrolides-lincosamide (ermB, ermA, sat(4), and linB), and tetracyclines (tetL, tetM, and tetO). The virulence genes expressing adhesion (ace, efaAfs, and agrBfs), gelatinase (gelE), and pheromone (cAM, ccF10, cob, and cpd1) factors were found in the majority of isolates. Significant associations were found between resistance and virulence genes, suggesting their possible relationship. These data suggest that carcasses entering the final product processing area are mostly free of E. faecalis but are recontaminated with antimicrobial-resistant strains during processing. The source of these contaminants remains to be identified; however, these results underscore the importance of E. faecalis as a reservoir of resistance and virulence genes.


2014 ◽  
Vol 63 (11) ◽  
pp. 1561-1567 ◽  
Author(s):  
Kazuki Harada ◽  
Ayaka Niina ◽  
Takae Shimizu ◽  
Yujiro Mukai ◽  
Ken Kuwajima ◽  
...  

Large-scale monitoring of resistance to 14 antimicrobial agents was performed using 103 Proteus mirabilis strains isolated from dogs in Japan. Resistant strains were analysed to identify their resistance mechanisms. Rates of resistance to chloramphenicol, streptomycin, enrofloxacin, trimethoprim/sulfamethoxazole, kanamycin, ampicillin, ciprofloxacin, cephalothin, gentamicin, cefoxitin and cefotaxime were 20.4, 15.5, 12.6, 10.7, 9.7, 8.7, 5.8, 2.9, 2.9, 1.9 and 1.9 %, respectively. No resistance to ceftazidime, aztreonam or imipenem was found. Class 1 and 2 integrases were detected in 2.9 and 11.7 % of isolates, respectively. Class 1 integrons contained aadB or aadB–catB-like-blaOXA10 –aadA1, whereas those of class 2 contained sat–aadA1, dhfr1–sat–aadA1 or none of the anticipated resistance genes. Of five distinct plasmid-mediated quinolone-resistance (PMQR) genes, only qnrD gene was detected in 1.9 % of isolates. Quinolone-resistance determining regions (QRDRs) of gyrA and parC from 13 enrofloxacin-intermediate and -resistant isolates were sequenced. Seven strains had double mutations and three had single mutations. Three of nine ampicillin-resistant isolates harboured AmpC-type β-lactamases (i.e. bla CMY-2, bla CMY-4 and bla DHA-1). These results suggest that canine Proteus mirabilis deserves continued surveillance as an important reservoir of antimicrobial resistance determinants. This is the first report, to our knowledge, describing integrons, PMQRs and QRDR mutations in Proteus mirabilis isolates from companion animals.


2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Melina Ruggiero ◽  
Delphine Girlich ◽  
Laura Dabos ◽  
Pablo Power ◽  
Thierry Naas ◽  
...  

ABSTRACTTheblaPER-2-harboring plasmid pCf587 (191,541 bp) belongs to lineage IncA/C1and is closely related to pRA1. It contains a large resistance island including theblaPER-2gene between two copies of ISKox2-like elements, the toxin-antitoxin modulepemK-pemI, several other resistance genes inserted within a Tn2transposon, a Tn21-like structure, and a class 1 integron. pCf587 belongs to sequence type 13 (ST13), a new plasmid multilocus sequence typing (pMLST) ST.


AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Quan Li ◽  
Jian Yin ◽  
Zheng Li ◽  
Zewei Li ◽  
Yuanzhao Du ◽  
...  

AbstractSalmonella is an important food-borne pathogen associated with public health and high economic losses. To investigate the prevalence and the characteristics of Salmonella in a pig slaughterhouse in Yangzhou, a total of 80 Salmonella isolates were isolated from 459 (17.43%) samples in 2016–2017. S. Derby (35/80, 43.75%) was the most prevalent, followed by S. Rissen (16/80, 20.00%) and S. Newlands (11/80, 13.75%). The highest rates of susceptibility were observed to cefoxitin (80/80, 100.0%) and amikacin (80/80, 100.0%), followed by aztreonam (79/80, 98.75%) and nitrofurantoin (79/80, 98.75%). The highest resistance rate was detected for tetracycline (65/80, 81.25%), followed by ampicillin (60/80, 75.00%), bactrim (55/80, 68.75%), and sulfisoxazole (54/80, 67.50%). Overall, 91.25% (73/80) of the isolates were resistant to at least one antibiotic, while 71.25% (57/80) of the isolate strains were multidrug resistant in the antimicrobial susceptibility tested. In addition, 86.36% (19/22) of the 22 antimicrobial resistance genes in the isolates were identified. Our data indicated that the resistance to certain antimicrobials was significantly associated, in part, with antimicrobial resistance genes. Furthermore, 81.25% (65/80) isolates harbored the virulence gene of mogA, of which 2 Salmonella Typhimurium isolates carried the mogA, spvB and spvC virulence genes at the same time. The results showed that swine products in the slaughterhouse were contaminated with multidrug resistant Salmonella commonly, especially some isolates carry the spv virulence genes. The virulence genes might facilitate the dissemination of the resistance genes to consumers along the production chain, suggesting the importance of controlling Salmonella during slaughter for public health.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S820-S820
Author(s):  
Bongyoung Kim ◽  
Ki Tae Kwon ◽  
Seong-yeol Ryu ◽  
Seong-Heon Wie ◽  
Hyun-uk Jo ◽  
...  

Abstract Background The aim of this study was to examine the change in characteristics of community-onset ciprofloxacin-resistant (CIP-R) E. coli isolates causing community-acquired acute pyelonephritis (CA-APN) in South Korea between 2010-2011 and 2017-2018. Methods E. coli samples isolated from the blood or urine were collected from patients with CA-APN aged 19 years and more who were admitted to 8 Korean hospitals from September 2017 to August 2018, prospectively. One isolate was collected from each patient. Phylogenetic typing, multilocus sequence typing (MLST), and molecular characterization of β-lactamase resistance and plasmid-mediated quinolone resistance (PMQR) determinants were performed. The data were compared with those from the previous study with same design in 2010-2011. Results A total of 346 and 300 isolates were collected during 2017-2018 and 2010-2011, respectively. Among them, 76 (22.0%) and 77 (25.7%) were CIP-R isolates. Significantly higher antimicrobial resistance against ampicillin (75.7% vs. 100%, P < 0.001) and cefotaxime (23.9% vs. 77.9%, P < 0.001) were observed for isolates in 2017-2018 compared to those in 2010-2011. The proportion of phylogenic group B2 had increased significantly (44.7% vs. 79.2%, P < 0.001). As for MLST, the proportion of ST131 (27.6% vs. 66.2%, P < 0.001) had increased while that of ST393 (18.4% vs. 3.9%, P =0.004) had decreased significantly. Higher proportion of CIP-R E. coli isolates in 2017-2018 had extended-spectrum β-lactamase (ESBL)/plasmid-mediated AmpC β-lactamase (PABL) (23.7% vs. 79.2%, P < 0.001) and PMQR determinant (11.8% vs. 40.8%, P < 0.001) compared to those in 2010-2011. Phlogenetic tree Analyzed by SplitsTree Conclusion Among uropathogenic CIP-R E. coli isolates in South Korea, ST131 predominance had become more prominent and the proportion of containing ESBL/PABL and/or PMQR determinants had increased. Disclosures All Authors: No reported disclosures


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