Insights into the genomic traits of Yersinia frederiksenii, Yersinia intermedia and Yersinia kristensenii isolated from diverse sources in Brazil.

Yersinia is an important genus comprising foodborne, zoonotic and pathogenic bacteria. On the other hand, species of the so-called group Yersinia enterocolitica-like are understudied and mostly characterized as non-pathogenic, despite of some reports of human infections. The present study aimed to provide genomic insights of Yersinia frederiksenii (YF), Yersinia intermedia (YI) and Yersinia kristensenii (YK) isolated worldwide. A total of 22 YF, 20 YI and 14 YK genomes were searched for antimicrobial resistance genes, plasmids, prophages, and virulence factors. Their phylogenomic relatedness was analyzed by Gegenees and core-genome multi-locus sequence typing. Beta-lactam resistance gene blaTEM-116 and five plasmids replicons (pYE854, ColRNAI, ColE10, Col(pHAD28) and IncN3) were detected in less than five genomes. A total of 59 prophages, 106 virulence markers of the Yersinia genus, associated to adherence, antiphagocytosis, exoenzymes, invasion, iron uptake, proteases, secretion systems and the O-antigen, and virulence factors associated to other 20 bacterial genera were detected. Phylogenomic analysis revealed high inter-species distinction and four highly diverse YF clusters. In conclusion, the results obtained through the analyses of YF, YI and YK genomes suggest the virulence potential of these strains due to the broad diversity and high frequency of prophages and virulence factors found. Phylogenetic analyses were able to correctly distinguish these closely related species and show the presence of different genetic subgroups. These data contributed for a better understanding of YF, YI and YK virulence-associated features and global genetic diversity, and reinforced the need for better characterization of these Y. enterocolitica-like species considered non-pathogenic.

Untargeted accurate identification of highly pathogenic bacteria directly from blood culture flasks.

To improve the preparedness against exposure to highly pathogenic bacteria and to anticipate the wide variety of bacteria that can cause bloodstream infections (BSIs), a safe, unbiased and highly accurate identification method was developed. Our liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method can identify highly pathogenic bacteria, their near-neighbors and bacteria that are common causes of BSIs directly from positive blood culture flasks. The developed Peptide-Based Microbe Detection Engine (http://proteome2pathogen.com) relies on a two-step workflow: a genus-level search followed by a species-level search. This strategy enables the rapid identification of microorganisms based on the analyzed proteome. This method was successfully used to identify strains of Bacillus anthracis, Brucella abortus, Brucella melitensis, Brucella suis, Burkholderia pseudomallei, Burkholderia mallei, Francisella tularensis, Yersinia pestis and closely related species from simulated blood culture flasks. This newly developed LC-MS/MS method is a safe and rapid method for accurately identifying bacteria directly from positive blood culture flasks.

Yersinia artesiana sp. nov., Yersinia proxima sp. nov., Yersinia alsatica sp. nov., Yersina vastinensis sp. nov., Yersinia thracica sp. nov. and Yersinia occitanica sp. nov., isolated from humans and animals.

Thirty-three Yersinia strains previously characterized by the French Yersinia National Reference Laboratory (YNRL) and isolated from humans and animals were suspected to belong to six novel species by a recently described core genome multilocus sequence typing scheme. These strains and five additional strains from the YNRL were characterized using a polyphasic taxonomic approach including a phylogenetic analysis based on 500 core genes, determination of average nucleotide identity (ANI), determination of DNA G+C content and identification of phenotypic features. Phylogenetic analysis confirmed that the 38 studied strains formed six well-demarcated clades. ANI values between these clades and their closest relatives were <94.7 % and ANI values within each putative novel species were >97.5 %. Distinctive biochemical characteristics were identified in five out of the six novel species. All of these data demonstrated that the 38 strains belong to six novel species of the genus Yersinia: Yersinia artesiana sp. nov., type strain IP42281T (=CIP 111845T=DSM 110725T); Yersinia proxima sp. nov., type strain IP37424T (=CIP 111847T=DSM 110727T); Yersinia alsatica sp. nov., type strain IP38850T (=CIP 111848T=DSM 110726T); Yersinia vastinensis sp. nov., type strain IP38594T (=CIP 111844T=DSM 110738T); Yersinia thracica sp. nov., type strain IP34646T (=CIP 111842T=DSM 110736T); and Yersinia occitanica sp. nov., type strain IP35638T (=CIP 111843T=DSM 110739T).

Yersinia canariae sp. nov., isolated from a human yersiniosis case.

A Gram-negative rod from the Yersinia genus was isolated from a clinical case of yersiniosis in the United Kingdom. Long read sequencing data from an Oxford Nanopore Technologies (ONT) MinION in conjunction with Illumina HiSeq reads were used to generate a finished quality genome of this strain. Overall Genome Related Index (OGRI) of the strain was used to determine that it was a novel species within Yersinia, despite biochemical similarities to Yersinia enterocolitica. The 16S ribosomal RNA gene accessions are MN434982-MN434987 and the accession number for the complete and closed chromosome is CP043727. The type strain is SRR7544370T (=NCTC 14382T/=LMG 31573T).

Yersinia hibernica sp. nov., isolated from pig-production environments.

A Gram-stain-negative, rod-shaped strain isolated from pig-production environments was identified as a new species within the genus Yersinia using multifaceted genomic and biochemical approaches. The genome of this strain was closed using a hybrid assembly approach combining both high accuracy short read sequencing data with long read sequencing technology. Phylogenetic analysis of the 16S rRNA gene showed ~98 % similarity to Yersinia kristensenii and ~98 % similarity to Yersinia enterocolitica. Average nucleotide identity (OrthoANI) values were calculated as 85.79 % to Y. kristensenii ATCC 33638T and 85.73 % to Y. enterocolitica ATCC 9610T thereby providing evidence that this isolate should be considered as a novel species. The type strain is CFS1934T (=NCTC 14222T=LMG 31076T).

Yersinia kristensenii subsp. rochesterensis subsp. nov., isolated from human feces.

A single bacterial isolate, EPLC-04T, was isolated from human feces and identified as representing a member of the genus Yersinia on the basis of phenotypic characteristics, matrix assisted laser desorption ionization time-of-flight mass spectrometry and partial 16S rRNA gene sequencing. The isolate's phenotypic profile differed from that described for the most closely related species, Yersinia kristensenii, by exhibiting lipase production and lacking pyrazinamidase activity. Multiple genetic targets, including the complete (1465 bp) 16S rRNA gene sequence and partial sequences of groEL (539 bp), gyrB (935 bp), glnA (525 bp) and recA (535 bp) indicated that the isolate exhibited 98.91, 92.16, 90.81, 92.78 and 89.01 % identity with Yersinia aldovae, 98.98, 91.99, 90.17, 89.77 and 89.55 % identity with Yersinia intermedia, and 99.66, 98.11, 98.50, 98.49 and 98.51 % identity with Y. kristensenii, respectively. Phylogenetic reconstructions based on the combination of the four housekeeping genes indicated that the isolate formed a unique branch, supported by a bootstrap value of 100 %. Digital DNA-DNA homology and 16S rRNA gene sequencing identified EPLC-04T as representing Y. kristensenii. However, the unique phenotypic traits and results of phylogenetic analysis indicate that it represents a novel subspecies of Y. kristensenii. The name Yersinia kristenseniisubsp. rochesterensis subsp. nov. is proposed for this novel taxon (type strain EPLC-04T=ATCC BAA-2637T, DSMZ 28595T).

Enhanced Binding Efficiency of Microcantilever Biosensor for the Detection of Yersinia.

A novel microcantilever sensor was batch fabricated for Yersinia detection. The microcantilever surface modification method was optimized by introducing a secondary antibody to increase the number of binding sites. A novel microfluidic platform was designed and fabricated successfully. A 30 µL solution could fully react with the microcantilever surface. Those routines enhanced the binding efficiency between the target and receptor on the microcantilever. With this novel designed microfluidic platform, the specific adsorption of 107 Yersinia on the beam surface with modified F1 antibody was significantly enhanced.

Identification of Yersinia enterocolitica isolates from humans, pigs and wild boars by MALDI TOF MS.

BACKGROUND: Yersinia enterocolitica is widespread within the humans, pigs and wild boars. The low isolation rate of Y. enterocolitica from food or environmental and clinical samples may be caused by limited sensitivity of culture methods. The main goal of present study was identification of presumptive Y. enterocolitica isolates using MALDI TOF MS. The identification of isolates may be difficult due to variability of bacterial strains in terms of biochemical characteristics. This work emphasizes the necessity of use of multiple methods for zoonotic Y. enterocolitica identification. RESULTS: Identification of Y. enterocolitica isolates was based on MALDI TOF MS, and verified by VITEK® 2 Compact and PCR. There were no discrepancies in identification of all human' and pig' isolates using MALDI TOF MS and VITEK® 2 Compact. However three isolates from wild boars were not decisively confirmed as Y. enterocolitica. MALDI TOF MS has identified the wild boar' isolates designated as 3dz, 4dz, 8dz as Y. enterocolitica with a high score of matching with the reference spectra of MALDI Biotyper. In turn, VITEK® 2 Compact identified 3dz and 8dz as Y. kristensenii, and isolate 4dz as Y. enterocolitica. The PCR for Y. enterocolitica 16S rDNA for these three isolates was negative, but the 16S rDNA sequence analysis identified these isolates as Y. kristensenii (3dz, 4dz) and Y. pekkanenii (8dz). The wild boar' isolates 3dz, 4dz and 8dz could not be classified using biotyping. The main bioserotype present within pigs and human faeces was 4/O:3. It has been shown that Y. enterocolitica 1B/O:8 can be isolated from human faeces using ITC/CIN culturing. CONCLUSION: The results of our study indicate wild boars as a reservoir of new and atypical strains of Yersinia, for which protein and biochemical profiles are not included in the MALDI Biotyper or VITEK® 2 Compact databases. Pigs in the south-west Poland are the reservoir for pathogenic Y. enterocolitica strains. Four biochemical features included in VITEK® 2 Compact known to be common with Wauters scheme were shown to produce incompatible results, thus VITEK® 2 Compact cannot be applied in biotyping of Y. enterocolitica.

Isothermal DNA amplification combined with lateral flow dipsticks for detection of biothreat agents.

The recently developed methods of nucleic acids isothermal amplification are promising tools for point-of-care diagnostics and in the field detection of pathogenic microorganisms. However, application of these methods outside a laboratory faces some challenges such as the rapid and sensitive detection of amplified products and the absence of cross-reactivity with genetically related microorganisms. In the presented study we compared three methods of isothermal DNA amplification loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA) and thermophilic helicase-dependent isothermal DNA amplification (tHDA), for detection of highly dangerous pathogens, such as Bacillus anthracis, Francisella tularensis and Yersinia pestis, and combined them with lateral flow dipsticks for the rapid visualization of amplified products. We observed low specificity of the three methods for B. antharcis, medium for Y. pestis and high for F. tularensis detection. Sensitivity and the detection limit were high and comparable for all the methods. We concluded that the lateral flow dipsticks have been a very useful tool for product detection of the isothermal amplification methods and enable reading the results without the use of any equipment. However, our results showed that the use of isothermal amplification methods is strongly related to the risk of false positive results.

[Antimicrobial susceptibility and drug-resistance genes of Yersinia spp. of retailed poultry in 4 provinces of China].

Objective: To monitor the antimicrobial resistance and drug-resistance genes of Yersinia enterocolitis, Y. intermedia and Y. frederiksenii recovered from retailed fresh poultry of 4 provinces of China. Methods: The susceptibility of 25 isolated Yersinia spp. to 14 classes and 25 kinds of antibiotics was determined by broth microdilution method according to CLSI (Clinical and Laboratory Standards Institute). The antibiotic resistance genes were predicted with antibiotic resistance genes database (ARDB) using whole genome sequences of Yersinia spp. Results: In all 22 Y. enterocolitis tested, 63.7% (14 isolates), 22.8% (5 isolates), 4.6% and 4.6% of 1 isolates exhibited the resistance to cefoxitin, ampicillin-sulbactam, nitrofurantoin and trimethoprim-sulfamethoxazole, respectively. All the 25 isolates were multi-drug resistant to more than 3 antibiotics, while 64.0% of isolates were resistant to more than 4 antibiotics. A few Y. enterocolitis isolates of this study were intermediate to ceftriaxone and ciprofloxacin. Most Yersinia spp. isolates contained antibiotic resistance genes mdtG, ksgA, bacA, blaA, rosAB and acrB, and 5 isolates recovered from fresh chicken also contained dfrA1, catB2 and ant3ia. Conclusion: The multi-drug resistant Yersinia spp. isolated from retailed fresh poultry is very serious in the 4 provinces of China, and their contained many kinds of drug-resistance genes.

Concentrations of Campylobacter spp., Escherichia coli, Enterococci, and Yersinia spp. in the Feces of Farmed Red Deer in New Zealand.

Intensive deer farming can cause environmental issues, mainly by its impact on soils and water quality. In particular, there is a risk to the microbial quality of water, as high quantities of suspended sediment and fecal bacteria can enter into water systems. The feces of farmed red deer (, = 206) from Canterbury and Southland, New Zealand, were analyzed with regard to the presence of spp., , enterococci, and spp.. Enterococci and were isolated from all samples, with mean concentrations of 4.5 × 10 (95% CI 3.5 × 10, 5.6 10) and 1.3 × 10 (95% CI 1.1 × 10, 1.5 × 10) per gram of dry feces, respectively. spp. were isolated from 27 fecal samples, giving an overall prevalence of 13.1%. isolation rates were variable within and between regions (Canterbury 7.95% [95% CI 2-14%], Southland 16.95% [95% CI 10-24%]). Five out of 42 composite samples were positive for , and one sample for The overall prevalence ranges on a per-animal basis were therefore 2.43 to 11.17% and 0.49 to 2.91%, respectively. This study is the first to quantify the concentration of spp. present in healthy deer farmed in New Zealand. Deer feces are a potential source of human campylobacteriosis, with all genotypes isolated also previously observed among human cases. The fecal outputs from deer should be regarded as potentially pathogenic to humans and therefore be appropriately managed.

The effects of culture independent diagnostic testing on the diagnosis and reporting of enteric bacterial pathogens in Queensland, 2010 to 2014.

Changes in diagnostic laboratory testing procedures can impact on the number of cases notified and the public health surveillance of enteric pathogens. Culture independent diagnostic testing using a multiplex polymerase chain reaction (PCR) test was introduced for the rapid detection of bacterial enteric pathogens in pathology laboratories in Queensland, Australia, from late 2013 onwards. We conducted a retrospective descriptive study using laboratory data to assess the impact of the introduction of PCR testing on four common enteric pathogens, Salmonella, Campylobacter, Shigella and Yersinia, in Queensland between 2010 and 2014. The number of stool specimens tested and the proportion positive for each of the four pathogens increased in 2014 after the introduction of culture independent diagnostic testing. Among the specimens tested by both PCR and culture, 12% of Salmonella positive stools, 36% of Campylobacter positive stools, 74% of Shigella / enteroinvasive Escherichia coli positive stools and 65% of Yersinia positive stools were PCR positive only. Including those where culture was not performed, 19% of Salmonella positive stools, 44% of Campylobacter positive stools, 83% of Shigella positive stools and 79% of Yersinia positive stools had no cultured isolate available for further characterisation. The detection and tracking of foodborne and non-foodborne gastrointestinal outbreaks will become more difficult as culture independent diagnostic testing becomes more widespread. Until new techniques for characterisation of pathogens directly from clinical specimens have been developed, we recommend laboratories continue to culture specimens concurrently or reflexively with culture independent diagnostic tests.

Characterization of Yersinia species by protein profiling using automated microfluidic capillary electrophoresis.

Yersinia pestis is a biological agent of high risk to national security due to its ability to be easily disseminated and transmitted among humans. If Y. pestis was to be utilized in a deliberate disease outbreak it would be essential to rapidly and accurately identify the agent. Current identification methods for Yersinia species are limited by their reliance on cultivation, the time taken to achieve results and/or the use of protocols that are not amenable for field use. Faster identification methods are urgently required. Microfluidic capillary electrophoresis was used to identify seven Yersinia species based on their protein profiles. Further objectives included determining if Yersinia species could be detected in mixtures of milk products and Escherichia coli, determining if Yersinia could be detected in a blinded identification and reproducibility across two platforms. Two characteristic protein bands were detected at 50 kilodaltons (kDa) and between 50 and 75 kDa for the Yersinia species. Individual Yersinia species could be differentiated from one another and distinguished from E. coli, Bacillus anthracis Sterne strain and Dipel (containing Bacillus thuringiensis). Due to the high protein content of milk products Yersinia could not be detected when mixed with these but was detected when mixed with E. coli. Species were correctly identified with 96% success in blinded procedures using 12 individuals. Whilst protein profile patterns were reproducible across platforms there was some discrepancy in protein sizing. This study demonstrates that protein profiling using microfluidic capillary electrophoresis is able to rapidly and reproducibly identify and characterize Yersinia species. Results show this technique is a powerful front-line, rapid and broad range screening method capable of identifying and differentiating biological agents, hoax agents and environmental bacterial species.

A prevalence study of Salmonella spp., Yersinia spp., Toxoplasma gondii and porcine reproductive and respiratory syndrome virus in UK pigs at slaughter.

An abattoir-based study was undertaken between January and May 2013 to estimate the prevalence of Salmonella spp. and Yersinia spp. carriage and seroprevalence of antibodies to Toxoplasma gondii and porcine reproductive and respiratory syndrome virus (PRRSv) in UK pigs at slaughter. In total, 626 pigs were sampled at 14 abattoirs that together process 80% of the annual UK pig slaughter throughput. Sampling was weighted by abattoir throughput and sampling dates and pig carcasses were randomly selected. Rectal swabs, blood samples, carcass swabs and the whole caecum, tonsils, heart and tongue were collected. Salmonella spp. was isolated from 30·5% [95% confidence interval (CI) 26·5-34·6] of caecal content samples but only 9·6% (95% CI 7·3-11·9) of carcass swabs, which was significantly lower than in a UK survey in 2006-2007. S. Typhimurium and S. 4,[5],12:i:- were the most commonly isolated serovars, followed by S. Derby and S. Bovismorbificans. The prevalence of Yersinia enterocolitica carriage in tonsils was 28·7% (95% CI 24·8-32·7) whereas carcass contamination was much lower at 1·8% (95% CI 0·7-2·8). The seroprevalence of antibodies to Toxoplasma gondii and PRRSv was 7·4% (95% CI 5·3-9·5) and 58·3% (95% CI 53·1-63·4), respectively. This study provides a comparison to previous abattoir-based prevalence surveys for Salmonella and Yersinia, and the first UK-wide seroprevalence estimates for antibodies to Toxoplasma and PRRSv in pigs at slaughter.

Serological Prevalence of Enteropathogenic Yersinia spp. in Pigs and Wild Boars from Different Production Systems in the Moravian Region, Czech Republic.

Human yersiniosis caused by pathogenic Yersinia spp. is one of the most common reported zoonoses in the European Union and pigs are considered as the major reservoir of these bacteria. Serological testing represents a suitable method to obtain information about the prevalence of enteropathogenic Yersinia spp. in food animals. The prevalence of antibodies against enteropathogenic Yersinia spp. was studied in 319 slaughtered pigs and 135 wild boars from different production systems in the Moravian region (Czech Republic) using a commercially available ELISA test (an apparent prevalence). The seroprevalence was significantly associated with the type of breeding system, with the lowest seroprevalence being observed in household-raised pigs (13/29, 44.8%). No significant difference between the prevalence of anti-Yersinia antibodies in conventional (146/180, 81.1%) and organic pigs (92/110, 83.6%) was found. Antibodies were found in 65.9% (89/135) of wild boars without a significant difference between adult (23/41, 56.1%) and young (66/94, 70.2%) animals. Seropositivity was significantly higher in domestic (251/319, 78.7% in total) compared to feral pigs. A Bayesian approach taking into account the sensitivity and specificity of the ELISA test was used to estimate the true prevalence of anti-Yersinia antibodies in pigs and wild boars. According to our results, domestic pigs and wild boars proved to be an important reservoir of enteropathogenic Yersinia in the Czech Republic. Attention should be paid to good hygienic practice during slaughtering and handling of meat to prevent meat contamination and subsequently human infection.

Use of whole-genus genome sequence data to develop a multilocus sequence typing tool that accurately identifies Yersinia isolates to the species and subspecies levels.

The genus Yersinia is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus. Here we report the mining of this enormous data set to create a multilocus sequence typing-based scheme that can identify Yersinia strains to the species level to a level of resolution equal to that for whole-genome sequencing. Our assay is designed to be able to accurately subtype the important human-pathogenic species Yersinia enterocolitica to whole-genome resolution levels. We also report the validation of the scheme on 386 strains from reference laboratory collections across Europe. We propose that the scheme is an important molecular typing system to allow accurate and reproducible identification of Yersinia isolates to the species level, a process often inconsistent in nonspecialist laboratories. Additionally, our assay is the most phylogenetically informative typing scheme available for Y. enterocolitica.

Bacterial enteric infections detected by culture-independent diagnostic tests--FoodNet, United States, 2012-2014.

The increased availability and rapid adoption of culture-independent diagnostic tests (CIDTs) is moving clinical detection of bacterial enteric infections away from culture-based methods. These new tests do not yield isolates that are currently needed for further tests to distinguish among strains or subtypes of Salmonella, Campylobacter, Shiga toxin-producing Escherichia coli, and other organisms. Public health surveillance relies on this detailed characterization of isolates to monitor trends and rapidly detect outbreaks; consequently, the increased use of CIDTs makes prevention and control of these infections more difficult. During 2012-2013, the Foodborne Diseases Active Surveillance Network (FoodNet*) identified a total of 38,666 culture-confirmed cases and positive CIDT reports of Campylobacter, Salmonella, Shigella, Shiga toxin-producing E. coli, Vibrio, and Yersinia. Among the 5,614 positive CIDT reports, 2,595 (46%) were not confirmed by culture. In addition, a 2014 survey of clinical laboratories serving the FoodNet surveillance area indicated that use of CIDTs by the laboratories varied by pathogen; only CIDT methods were used most often for detection of Campylobacter (10%) and STEC (19%). Maintaining surveillance of bacterial enteric infections in this period of transition will require enhanced surveillance methods and strategies for obtaining bacterial isolates.

Pathogenic enterobacteria in lemurs associated with anthropogenic disturbance.

As human population density continues to increase exponentially, speeding the reduction and fragmentation of primate habitat, greater human-primate contact is inevitable, making higher rates of pathogen transmission likely. Anthropogenic effects are particularly evident in Madagascar, where a diversity of endemic lemur species are threatened by rapid habitat loss. Despite these risks, knowledge of how anthropogenic activities affect lemur exposure to pathogens is limited. To improve our understanding of this interplay, we non-invasively examined six species of wild lemurs in Ranomafana National Park for enteric bacterial pathogens commonly associated with diarrheal disease in human populations in Madagascar. Patterns of infection with Enterotoxigenic Escherichia coli, Shigella spp., Salmonella enterica, Vibrio cholerae, and Yersinia spp. (enterocolitica and pseudotuberculosis) were compared between lemurs inhabiting intact forest and lemurs inhabiting degraded habitat with frequent exposure to tourism and other human activity. Fecal samples acquired from humans, livestock, and rodents living near the degraded habitat were also screened for these bacteria. Remarkably, only lemurs living in disturbed areas of the park tested positive for these pathogens. Moreover, all of these pathogens were present in the human, livestock, and/or rodent populations. These data suggest that lemurs residing in forests altered or frequented by people, livestock, or peridomestic rodents, are at risk for infection by these diarrhea-causing enterobacteria and other similarly transmitted pathogens.

Prevalence, characterization, and antimicrobial resistance of Yersinia species and Yersinia enterocolitica isolated from raw milk in farm bulk tanks.

The aims of this study were to investigate the prevalence and to characterize and determine the antibiotic resistance of Yersinia spp. isolates from raw milk. From September 2008 to August 2010, 446 raw milk samples were obtained from farm bulk milk tanks in Varamin, Iran. Yersinia spp. were detected in 29 (6.5%) samples, out of which 23 (79.3%), 5 (17.2%), and 1 (3.4%) were isolated from cow, sheep, and goat raw milk, respectively. The most common species isolated was Yersinia enterocolitica (65.5%), followed by Yersinia frederiksenii (31%), and Yersinia kristensenii (3.4%). Of the 19 Y. enterocolitica isolates, 14 (73.7%) were grouped into bioserotype 1A/O:9, 4 (21.1%) belonged to bioserotype 1B:O8, 1 (5.3%) belonged to bioserotype 4/O:3, and 1 isolate (biotype 1A) was not typable. All the isolates of biotypes 1B and 4harbored both the ystA and ail genes. However, all the isolates of biotype 1A were only positive for the ystB gene. The tested Yersinia spp. showed the highest percentages of resistance to tetracycline (48.3%), followed by ciprofloxacin and cephalothin (each 17.2%), ampicillin (13.8%), streptomycin (6.9%), and amoxicillin and nalidixic acid (each 3.4%). All of the tested isolates demonstrated significant sensitivity to gentamicin and chloramphenicol. Recovery of potentially pathogenic Y. enterocolitica from raw milk indicates high risks of yersiniosis associated with consumption of raw milk.

Antibiotic resistance versus antimicrobial substances production by gram-negative foodborne pathogens isolated from minas frescal cheese: heads or tails?

In this study, 15 Gram-negative isolates from Minas Frescal cheese sold in commercial establishments in Rio de Janeiro, Brazil, were able to produce antimicrobial substances (AMSs). Seven, four, two, one, and one isolates identified as Yersinia, Acinetobacter, Enterobacter, Escherichia, and Hafnia genera, respectively, were considered potentially pathogenic. All 15 AMS(+) isolates were resistant to at least 1 antibiotic; however, 7 strains presented resistance to at least 3 antibiotics from different classes, exhibiting multiresistance profiles. The strains were also subjected to plasmid profile analysis. All isolates presented different plasmid forms with most ranging in size from 1 to 10 kb. Activity against various pathogens associated with food was tested and all 15 AMS(+) showed the same activity spectrum, inhibiting all Escherichia coli and Salmonella strains that were tested. Although restricted, the action spectrum of AMS-producing strains is extremely relevant to the food industry because Gram-negative bacteria such as E. coli and Salmonella spp. are most often associated with foodborne illnesses. The findings of this study reveal that even AMS produced by pathogens can have potential applications against other foodborne pathogens.