Detection of linezolid-resistant enterococci carrying optrA and/or poxtA in raw-frozen dog foods commercialised in the EU: trend or threat?

by Nicole Decrisantis
May 6, 2020

1. This is an abstract, not a peer reviewed paper. It is premature to go to the international press. Interesting to discuss at a conference, but not for worldwide distribution. Bad science.

2. Fundamental flaw in the study: They conclude with: ‘The close contact of pets with humans and the commercialization of the studied brands in different EU countries pose an international Public Health risk if transmission of such strains occurs between dogs and humans.’ THEY DID NOT STUDY THE TRANSMISSION OF BACTERIA FROM DOGS TO HUMANS

3. In Anna Heilm-Bjorkmann’s 2019 study:

  1. a. Over 90,000 dog years were studied. Only 3 cases of perceived risk from transmission of bacteria from dogs to humans. Of more disease risk to adults was having children at nursery school by  a factor of over 100%.

4. From the Finisterra paper: ‘Enterococcus (n=163) were identified in 19/46 (41%) (8/15-dry, 2/22-wet, 9/9-raw)of samples and identified as Efm (n=91), E. faecalis (Efs, n=59) or other species(n=13). Eighty-four were deeply studied.’

So  almost half the dry samples were contaminated, but they are not mentioned in the study.
b. All 9 raw products contain Enteros. They were ‘deeply’ studied.
c. What happened to the contaminated dry samples?
d. Why were only 84 of the 163 contaminated foods studied, how were they selected?

5. If MDR Enterococci are found in frozen raw in Portugal, this reflects badly on agriculture in Portugal

a. Farms, Haulage, Markets, Abattoir and Meat Distribution infrastructure and personnel MUST be equally contaminated.

6. Antibiotic resistance issues:
However, some strains of E. faecium may be pathogenic and harmful to humans, and can cause bacteraemia, endocarditis, urinary tract and other infections. Moreover, anti-microbial resistance (AMR) to many commonly used antibiotics has been reported, and E. faecium is the leading cause of multi-drug resistant enterococcal infections in humans. It is thought that about 70% of E. faecium strains in US hospitals are resistant to vancomycin and 90% are resistant to ampicillin. E. faecium resistance is acquired by gene transfer systems, such as conjugative and non-conjugative plasmids or transposons. Virulence of E. faecium strains is not well understood, but adhesins, haemolysin, hyaluronidase, aggression substance and gelatinase are putative virulence factors. These virulence genes may be transferred to human endogenous strains present in the gastrointestinal tract, which may contribute to increasing the virulence factors of this genus and endogenous strains. Concerns over the safety of E. faecium for use as a probiotic food supplement have been raised due to the propensity of this microbe to develop and acquire AMR, especially to vancomycin and ampicillin. The US and Taiwan FDA (Food and Drug Administration) believe that, in general, AMR can be transferred from “wild-type” bacteria residing in the gut to probiotics in transit through the gut. Proving that a probiotic strain is “safe from transfer of drug tolerance” is difficult. However, safe strains cannot transmit AMR if they have no AMR or toxin/virulence genes in the genome therefore, the risk of acquiring and further disseminating AMR by safe E. faecium strains is relatively low under practical use conditions, since exogenous probiotic strains disappear quickly from the gut, as the endogenous flora predominates over time. There is a global consensus to restrict and reduce antibiotic use, so that wild AMR genes diminish in the gut of both humans and animals, and less bacteria develop/acquire antibiotic-resistance. Without proper functioning antimicrobials, medicines become ineffective and treatment of infections becomes challenging, ultimately threatening global public health. Consequently, health authorities all over the world are closely monitoring the development of AMR, including the use of E. faecium as a probiotic in food and feed. Interestingly, there are conflicting views and different regulatory approaches to E. faecium around the world.

a. From:

7. Various opinions exist as to whether it might be desirable that some probiotic strains show resistance to specific antibiotics. On the one hand, some lactic acid bacteria can serve as host for antibiotic resistance genes and transfer these genes to pathogens. However, many of the resistance observed are intrinsic or natural resistance and non-transmissible (Salminen et al., 1998; Voravuthikunchai et al., 2006). It gives advantages in the clinical application, as this allows the probiotic to be taken at the same time as the antibiotic treatment. Resistance of enterococci to gentamicin has been described as intrinsic and partially attributed to a poor uptake of the antibiotic (Kristich et al., 2014). Resistance to erythromycin seems to be intrinsic as well, non-transmissible, and is widely spread among enterococci commonly found in foods (Barbosa et al., 2009). Recently, a high rate of erythromycin resistance has also been detected among Enterococci isolated from Artisanal Tunisian Meat “Dried Ossban” (Zommiti et al., 2018).

a. From:

From the same meeting: Abstract Title: Molecular detection of the mcr-1 mobile colistin resistance gene in healthy humans and a dog with skin infection from Portugal Session Title: Juliana Menezes*1, Adriana Belas1, Inês Cunha e Silva1, Maria Constança Pomba1

a. NO mention of what the dog ate!

9. From the same meeting: • Abstract Title: The transmission risk of multidrug-resistant organisms between pets and humans: n exploratory case control study protocol•

a. Conclusions: A univariate analysis of preliminary data showed no significant difference in pet husbandry or closeness of contact to pets between MDRO-positive and MDRO negative hospital patients. A transmission of MDROs between human and animal was  confirmed in only 1.8% of 112 pet owners and their respective pets. So far, the preliminary data does not indicate pet husbandry as a significant factor for MDRO colonization in hospital patients