Known mechanisms account for less than half of antimicrobial resistance in a diverse collection of non-aureus staphylococci.

Introduction: Non-aureus staphylococci (NAS) are implicated in many healthcare-acquired infections and an understanding of the genetics of antimicrobial resistance in NAS is important in relation to both clinical intervention and the role of NAS as a reservoir of resistance genes. Gap statement: The burden of antimicrobial resistance in NAS, particularly to clinically relevant antimicrobials, is understudied. Methodology: We sourced 394 NAS isolates from clinical samples, healthy human volunteers, animals and type cultures and subjected them to agar dilution susceptibility testing against eight antimicrobials. We performed whole genome sequencing on 316 isolates and analysed these genotypically for the presence of genetic mechanisms responsible for the phenotypic levels of reduced antimicrobial susceptibility. Results: Cefoxitin is used to screen for methicillin resistance in S. aureus, as it stimulates expression of mecA. We observed 174 isolates with an MIC of at least 4 μg/ml to cefoxitin, of which sequencing revealed 47.6% (80/168) did not harbour a known mec homologue. Seven clinical NAS isolates displayed high daptomycin minimum inhibitory concentrations (MICs) (>4 μg/ml), with no known mechanism identified. Differences in MICs against erythromycin were attributable to the presence of different resistance genes (msrA and ermC). In total, 49% (187/394) of isolates displayed reduced susceptibility to three or more of the antimicrobials tested. Conclusions: The widespread presence of reduced antimicrobial susceptibility in NAS is a concern, with an increased likelihood of (1) harder to treat infections caused directly by NAS, and (2) resistance genes being passed on to other bacteria via horizontal gene transfer, both of which have clinical implications for treatment and management of patients.

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Serotype distribution, antimicrobial susceptibility, antimicrobial resistance genes and virulence genes of Salmonella isolated from a pig slaughterhouse in Yangzhou, China

AMB Express ◽

10.1186/s13568-019-0936-9 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Quan Li ◽

Jian Yin ◽

Zheng Li ◽

Zewei Li ◽

Yuanzhao Du ◽

...

Keyword(s):

Public Health ◽

Antimicrobial Resistance ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Virulence Genes ◽

Multidrug Resistant ◽

Resistance Rate ◽

Economic Losses ◽

Production Chain ◽

Antimicrobial Resistance Genes

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.

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High Frequency of Multidrug-resistant (Mdr) Klebsiella Pneumoniae Harboring Several β-lactamase and Integron Genes Collected From Several Hospitals in the North of Iran

10.21203/rs.3.rs-260577/v1 ◽

2021 ◽

Author(s):

Mojgan Farhadi ◽

Mohammad Ahanjan ◽

Hamid Reza Goli ◽

Mohammad Reza Haghshenas ◽

Mehrdad Gholami

Keyword(s):

Klebsiella Pneumoniae ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Hospitalized Patients ◽

Clinical Samples ◽

High Morbidity ◽

Drug Resistant ◽

The North ◽

Agar Diffusion Test ◽

North Of Iran

Abstract Background: Klebsiella pneumoniae is one of the leading causes of hospital outbreaks worldwide. Also, antibiotic-resistant K. pneumoniae is progressively being involved in invasive infections with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the incidences of resistance genes (integron types and β-lactamase-encoded genes) among clinical isolates of K. pneumoniae. Methods: In this cross-sectional study, a total of 100 clinical samples were obtained from hospitalized patients in three teaching hospitals in the north of Iran, from November 2018 and October 2019. Antimicrobial susceptibility testing was performed using disk agar diffusion test in line with CLSI recommendation. For colistin, minimum inhibitory concentration (MIC) was determined using broth microdilution. Based on antibiogram, multi-drug resistant (MDR) and extensive-drug resistant (XDR) strains were detected. Finally, integron types and β-lactamase resistance genes were identified using polymerase chain reaction technique.Results. The most and least clinical samples were related to the urine and bronchoalveolar lavage, respectively. Based on the antibiogram results, amikacin and gentamicin exhibited good activity against K. pneumoniae strains in vitro. High resistance rate (93%) to ampicillin/sulbactam also predict the limited efficacy of this antibiotic. Among all the 100 isolates, the frequency of MDR and XDR strains were 58% and 13%, respectively, while no pan-drug resistant (PDR) isolates were found. The prevalence of blaSHV, blaTEM, blaCTX-M-15, blaKPC, blaOXA-48, blaNDM β-lactamase genes were 91.4%, 82.7%, 79.3%, 29.3%, 36.2% and 6.9%, respectively, however 58% of the isolates were carrying intI gene. Class II and III integrons were not detected in any isolates. Conclusion: The MDR K. pneumoniae is becoming a serious problem in hospitals, with many strains developing resistance to most available antimicrobials. Our results indicate co-presence of a series of β-lactamase and integron types on the MDR strains recovered from hospitalized patients. The increasing rate of these isolates emphasizes the importance of choosing an appropriate antimicrobial regimen based on antibiotic susceptibility pattern.

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Prevalence of Cefotaxime-Resistant Escherichia coli Isolates from Healthy Cattle and Sheep in Northern Spain: Phenotypic and Genome-Based Characterization of Antimicrobial Susceptibility

Applied and Environmental Microbiology ◽

10.1128/aem.00742-20 ◽

2020 ◽

Vol 86 (15) ◽

Cited By ~ 1

Author(s):

Maitane Tello ◽

Medelin Ocejo ◽

Beatriz Oporto ◽

Ana Hurtado

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Basque Country ◽

Northern Spain ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Cattle Herds ◽

Cattle And Sheep

ABSTRACT In order to estimate herd-level prevalence of extended-spectrum β-lactamase/AmpC β-lactamase (ESBL/AmpC)- and carbapenemase-producing commensal Escherichia coli in ruminants in the Basque Country (northern Spain), a cross-sectional survey was conducted in 2014 to 2016 in 300 herds using selective isolation. ESBL-/AmpC-producing E. coli was isolated in 32.9% of dairy cattle herds, 9.6% of beef cattle herds, and 7.0% of sheep flocks. No carbapenemase-producing E. coli was isolated. Phenotypic antimicrobial susceptibility determined by broth microdilution using EUCAST epidemiological cutoff values identified widespread coresistance to extended-spectrum cephalosporins and other antimicrobials (110/135 isolates), particularly tetracycline, sulfamethoxazole, trimethoprim, and ciprofloxacin. All isolates were susceptible to tigecycline, imipenem, meropenem, and colistin. The genomes of 66 isolates were sequenced using an Illumina NovaSeq 6000 and screened for antimicrobial resistance determinants against ResFinder and PointFinder. The plasmid/chromosomal locations of resistance genes were predicted with PlasFlow, and plasmid replicons were identified using PlasmidFinder. Fifty-two acquired resistance genes and point mutations in another four genes that coded for resistance to 11 antimicrobial classes were identified. Fifty-five genomes carried ESBL-encoding genes, blaCTX-M-14 being the most common, and 11 carried determinants of the AmpC phenotype, mostly the blaCMY-2 gene. Additionally, genes coding for β-lactamases of the CTX-M group 9 were detected as well as the sporadic presence of blaSHV-12, blaCMY-4, and a point mutation in the ampC promoter. Only a bovine isolate coharbored more than one ESBL/AmpC genetic determinant (blaCTX-M-14 and a mutation in the ampC promoter), confirming its ESBL- and AmpC β-lactamase-producing phenotype. Most ESBL/AmpC genes were located in IncI1 plasmids, which also carried a great variety of other antimicrobial resistance genes. IMPORTANCE Extended-spectrum β-lactamase (ESBL)- and AmpC β-lactamase (AmpC)-producing E. coli isolates have emerged in recent years as some of the fastest spreading antimicrobial resistance determinants in humans and food-producing animals, becoming a concern for animal and public health. This study provided insight into the prevalence of cefotaxime-resistant E. coli in cattle and sheep in the Basque Country and the associated genetic determinants of antimicrobial resistance. These constituted an important contribution to the limited repository of such data for cattle in the region and for sheep worldwide. Antimicrobial susceptibility testing by phenotypic and molecular methods is key in surveillance programs to enhance early detection of resistance development, monitor resistance trends, and provide guidance to clinicians in selecting the adequate therapy.

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Antimicrobial Resistance in Bacteria Isolated From Cats and Dogs From the Iberian Peninsula

Frontiers in Microbiology ◽

10.3389/fmicb.2020.621597 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yanli Li ◽

Rubén Fernández ◽

Inma Durán ◽

Rafael A. Molina-López ◽

Laila Darwich

Keyword(s):

Antimicrobial Resistance ◽

Respiratory Tract ◽

Iberian Peninsula ◽

Antimicrobial Susceptibility ◽

Respiratory Tract Infections ◽

Antimicrobial Agents ◽

Close Contact ◽

Clinical Samples ◽

Private Laboratory ◽

Tract Infections

Pet animals are assumed to be potential reservoirs in transferring antimicrobial resistance (AMR) to humans due to the extensively applied broad-spectrum antimicrobial agents and their close contact with humans. In this study, microbiological data and antimicrobial susceptibility results of dog (n = 5,086) and cat (n = 789) clinical samples from a private Laboratory of Diagnosis in Barcelona were analyzed. Samples came from different counties of the Iberian Peninsula during 2016–2018. In dogs, clinical samples were most commonly from otitis, and in cats from wounds, respiratory tract infections and conjunctivitis. In both pet groups, Staphylococcus spp. (31% in dogs vs 30% in cats), Streptococcus spp. (19% vs 17%), Pseudomonas spp. (16% vs 10%), Escherichia coli (8% vs 5.6%), and Enterococcus spp. (5.5% vs 6.8%) were shown as the most predominant bacteria. However, higher frequencies of P. aeruginosa, P. canis, and S. pseudintermedius were found in dogs, while S. aureus and P. multocida were more prevalent in cats. The antimicrobial susceptibility testing demonstrated that Enterococcus spp. and Pseudomonas spp. presented the highest levels of AMR in both dogs and cats. Within the Enterobacteriaceae, E. coli showed low levels of AMR compared to Klebsiella, Proteus, or Enterobacter spp. Respiratory tract infections caused by K. pneumoniae presented higher AMR in cats. By contrast, Pasteurella isolates from the respiratory tract were highly sensitive to all the antimicrobials in cats and dogs. Data from this study could be used to guide empirical antimicrobial selection in companion animal veterinary practices in the Iberian Peninsula.

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Antimicrobial susceptibility, multilocus sequence typing, and virulence of listeria isolated from a slaughterhouse in Jiangsu, China

BMC Microbiology ◽

10.1186/s12866-021-02335-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Liting Wu ◽

Hongduo Bao ◽

Zhengquan Yang ◽

Tao He ◽

Yuan Tian ◽

...

Keyword(s):

Antibiotic Resistance ◽

Antimicrobial Resistance ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Multilocus Sequence Typing ◽

Tetracycline Resistance ◽

Dilution Method ◽

Processing Plant ◽

Meat Processing ◽

Processing Plants

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.

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The Russian gonococcal antimicrobial susceptibility programme (RU-GASP) – national resistance prevalence in 2007 and 2008, and trends during 2005-2008

Eurosurveillance ◽

10.2807/ese.15.14.19533-en ◽

2010 ◽

Vol 15 (14) ◽

Author(s):

A Kubanova ◽

N Frigo ◽

A Kubanov ◽

S Sidorenko ◽

I Lesnaya ◽

...

Keyword(s):

Public Health ◽

European Union ◽

Antimicrobial Resistance ◽

Antimicrobial Susceptibility ◽

Dilution Method ◽

Agar Dilution Method ◽

The European Union ◽

Beta Lactam ◽

First Line ◽

Agar Dilution

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major problem worldwide. In the former Soviet countries including Russia, the knowledge regarding AMR has been highly limited. However, in 2004 the Russian gonococcal antimicrobial susceptibility programme (RU-GASP) was initiated. The aims of this study were to examine and describe the prevalence of N. gonorrhoeae AMR in 2007 and 2008 in Russia, and reveal trends in the period from 2005 to 2008. Gonococcal isolates (660 in 2007 and 900 in 2008) from 36 surveillance sites were examined using agar dilution method. From 2005 to 2008, the proportion of isolates resistant to spectinomycin increased from 0% to 7.2%, and remained high for those resistant to ciprofloxacin (approximately 49%). The resistance to azithromycin was 2.3% and 0.4% in 2007 and 2008, respectively. All isolates between 2005 and 2008 were susceptible to ceftriaxone. In conclusion, the AMR of N. gonorrhoeae in Russia is high, as in most countries in the European Union, and ceftriaxone should be the first line for treatment. If there is no access to ceftriaxone or in the presence of severe beta-lactam antimicrobial allergy, spectinomycin should be used; however, the resistance to spectinomycin has increased. Regular, quality-assured national and international surveillance of AMR in N. gonorrhoeae is crucial globally for public health.

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High frequency of multidrug-resistant (MDR) Klebsiella pneumoniae harboring several β-lactamase and integron genes collected from several hospitals in the north of Iran

Annals of Clinical Microbiology and Antimicrobials ◽

10.1186/s12941-021-00476-1 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Mojgan Farhadi ◽

Mohammad Ahanjan ◽

Hamid Reza Goli ◽

Mohammad Reza Haghshenas ◽

Mehrdad Gholami

Keyword(s):

Klebsiella Pneumoniae ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Hospitalized Patients ◽

Clinical Samples ◽

High Morbidity ◽

Drug Resistant ◽

The North ◽

Agar Diffusion Test ◽

North Of Iran

Abstract Background Klebsiella pneumoniae is one of the leading causes of hospital outbreaks worldwide. Also, antibiotic-resistant K. pneumoniae is progressively being involved in invasive infections with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the incidence of resistance genes (integron types and β-lactamase-encoded genes) among clinical isolates of K. pneumoniae. Methods In this cross-sectional study, a total of 100 clinical samples were obtained from hospitalized patients in three teaching hospitals in the north of Iran, from November 2018 and October 2019. Antimicrobial susceptibility testing was performed using disk agar diffusion test in line with CLSI recommendations. For colistin, minimum inhibitory concentration (MIC) was determined using broth microdilution. Based on antibiogram, multi-drug resistant (MDR) and extensive-drug resistant (XDR) strains were detected. Finally, integron types and β-lactamase resistance genes were identified using polymerase chain reaction technique. Results The most and least clinical samples were related to the urine and bronchoalveolar lavage, respectively. Based on the antibiogram results, amikacin and gentamicin exhibited good activity against K. pneumoniae strains in vitro. The high resistance rate (93%) to ampicillin/sulbactam predicts the limited efficacy of this antibiotic, in the hospitals studied. Among all the 100 isolates, the frequency of MDR and XDR phenotypes were 58% and 13%, respectively, while no pan-drug resistant (PDR) strains were found. In the MDR K. pneumoniae strains, the prevalence of blaSHV, blaTEM, blaCTX-M-15, blaKPC, blaOXA-48, blaNDM β-lactamase genes were 91.4%, 82.7%, 79.3%, 29.3%, 36.2% and 6.9%, respectively, however 91.4% of the isolates were carrying intI gene. Class II and III integrons were not detected in any isolates. Conclusion The MDR K. pneumoniae is becoming a serious problem in hospitals, with many strains developing resistance to most available antimicrobials. Our results indicate co-presence of a series of β-lactamase and integron types on the MDR strains recovered from hospitalized patients. The increasing rate of these isolates emphasizes the importance of choosing an appropriate antimicrobial regimen based on antibiotic susceptibility pattern.

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Antimicrobial Susceptibility and Detection of Genes for Antimicrobial Resistance of Mycoplasma bovis, Staphylococcus aureus and Escherichia coli

Indian Journal of Animal Research ◽

10.18805/ijar.b-1343 ◽

2021 ◽

Author(s):

A. Aksoy

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Antimicrobial Susceptibility ◽

Penicillin G ◽

Dilution Method ◽

Agar Dilution Method ◽

Mycoplasma Bovis ◽

A Cell ◽

Agar Dilution

Background: Mycoplasma bovis (Gram-positive bacteria) belongs the class Mollicutes and to the family Mycoplasmataceae (Maunsell and Donovan, 2009). It is a cell wall-less bacterium and are instead enveloped by a complex plasma membrane. In cattle, M. bovis is widely known causes various diseases, such respiratory disease, mastitis, arthritis and otitis.Methods: The present study was aimed to determine the antimicrobial susceptibility and identify the genes for antimicrobial resistance of Mycoplasma bovis PG45, Staphylococcus aureus and Escherichia coli. M. bovis PG45, S. aureus and E.coli were subjected to test for their sensitivity to various clinically important antibiotics (Cefotaxime, Cefuroxime, Cefaclor Cefalexin, Ofloxacin, Norfloxacin, Nalidixic acid, Amikacin, Ampicillin, Oxacilin, Amoxyclav, Rifampicin, Penicillin G and Tylosin). The minimal inhibitory concentration (MIC) of each antimicrobial agent was determined by applying an agar dilution method. Polymerase Chain reaction (PCR) was used to amplify specific DNA fragments and thus to determine the presence or absence of a target gene (VspA, tet k and tetA). Result: Showed the MIC values and the presence of VspA, tetK and tetA in M. bovis PG45, S. aureus and E. coli respectively.

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Serotyping, Antimicrobial Resistance Profile and Virulence Genes of Salmonella Serovars Isolated from Human, Animals and Birds

10.21203/rs.3.rs-681026/v1 ◽

2021 ◽

Author(s):

Probodh Borah ◽

Rupam Dutta ◽

Leena Das ◽

Girin Hazarika ◽

Mridusmita Choudhary ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Continuous Monitoring ◽

Virulence Genes ◽

Molecular Detection ◽

Drug Resistant ◽

Antimicrobial Resistance Profile ◽

Monitoring And Surveillance ◽

Potential Risks

Abstract The study was undertaken to investigate the prevalence, antimicrobial susceptibility, antimicrobial resistance and virulence genes of Salmonella isolates recovered from human and different species of animals and birds. Out of 88 (7.15%), 21 (23.86%) belonged to Salmonella enterica subsp. enterica serovar Weltevreden, 22 (25%) to serovar Enteritidis, 16 (18.2%) to serovar Typhi and 14 (15.9%) to serovar Newport, while 7 (7.95%) isolates were found to be untypable. Among the 88 isolates, 45.45% showed resistance to ampicillin, 61.36% to tetracycline, 61.18% to cefotaxime, 65.90% to gentamicin, 48.86% to trimethoprim, 11.36% to ceftriaxone, 10.22% to chloramphenicol, and 7.95% each to ciprofloxacin and cefepime. Most of the isolates were susceptible to a low MIC (≤ 0.25 µg/ml) of Cefepime, Cefotaxime, Ciprofloxacin, Ceftriaxone and Co-trimoxazole and a moderate MIC (0.5µg/ml − 4µg/ml) of Ampicillin, Tetracycline, Gentamicin and Chloramphenicol. The resistance genes, blaTEM, tetA and dfrA12 were most prevalent, irrespective of the host of origin of the isolates. While invA was used for molecular detection of Salmonella, other virulence genes, viz. sipA, sipB, sipC, stn and T2544 were also detected in all (100%) the Salmonella isolates. Total 69.32 % of tested samples were found to be contaminated with multi-drug resistant (MDR) Salmonella and various virulence genes were present among the isolated serovars. Another virulence-associated gene, T2544 (pagN) could also be found in all the isolates, irrespective of serovar or host of origin suggesting the possibility of using this gene as a marker for identification of pathogenic Salmonella isolates. This study highlights the importance of continuous monitoring and surveillance for pathogenic salmonellae and their potential risks to both human and animal.

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Antimicrobial Susceptibility, Multilocus Sequence Typing, and Virulence of Listeria Isolated From A Slaughterhouse

10.21203/rs.3.rs-590420/v1 ◽

2021 ◽

Author(s):

Liting Wu ◽

Hongduo Bao ◽

Zhengquan Yang ◽

Tao He ◽

Yuan Tian ◽

...

Keyword(s):

Antibiotic Resistance ◽

Antimicrobial Resistance ◽

Resistance Genes ◽

Antimicrobial Susceptibility ◽

Multilocus Sequence Typing ◽

Tetracycline Resistance ◽

Dilution Method ◽

Processing Plant ◽

Meat Processing ◽

Processing Plants

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.

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