Antibiotic Resistant Pseudomonas Spp. Spoilers in Fresh Dairy Products: An Underestimated Risk and the Control Strategies

Abstract

Microbial multidrug resistance (MDR) is a growing threat to public health mostly because it makes the fight against microorganisms that cause lethal infections ever less effective. Thus, the surveillance on MDR microorganisms has recently been strengthened, taking into account the control of antibiotic abuse as well as the mechanisms underlying the transfer of antibiotic genes (ARGs) among microbiota naturally occurring in the environment. Indeed, ARGs are not only confined to pathogenic bacteria, whose diffusion in the clinical field has aroused serious concerns, but are widespread in saprophytic bacterial communities such as those dominating the food industry. In particular, fresh dairy products can be considered a reservoir of Pseudomonas spp. resistome, potentially transmittable to consumers. Milk and fresh dairy cheeses products represent one of a few “hubs” where commensal or opportunistic pseudomonads frequently cohabit together with food microbiota and hazard pathogens even across their manufacturing processes. Pseudomonas spp., widely studied for food spoilage effects, are instead underestimated for their possible impact on human health. Recent evidences have highlighted that non-pathogenic pseudomonads strains (P. fluorescens, P. putida) are associated with some human diseases, but are still poorly considered in comparison to the pathogen P. aeruginosa. In addition, the presence of ARGs, that can be acquired and transmitted by horizontal genetic transfer, further increases their risk and the need to be deeper investigated. Therefore, this review, starting from the general aspects related to the physiological traits of these spoilage microorganisms from fresh dairy products, aims to shed light on the resistome of cheese-related pseudomonads and their genomic background, current methods and advances in the prediction tools for MDR detection based on genomic sequences, possible implications for human health, and the affordable strategies to counteract MDR spread.

Biofilm and Pathogenesis-Related Proteins in the Foodborne P. fluorescens ITEM 17298 With Distinctive Phenotypes During Cold Storage

“…Only few species are classified opportunistic human pathogens and phytopathogens ( Pseudomonas aeruginosa, Pseudomonas syringae , and Pseudomonas cichorii ; de Bentzmann and Plésiat, 2011 ; Ichinose et al, 2013 ). However, an increasing number of Pseudomonas strains, without the issue of pathogenicity, have displayed multiple drug resistances, raised from horizontal transfer of genetic elements or inheritable mutations, which pose a severe threat to human health ( Guzel et al, 2018 ; Quintieri et al, 2019a ). Moreover, the isolation of non-pathogenic pseudomonads strains from clinical human cases has rapidly increased.…”

“…Among these, indeed, pigments modulate the transition to planktonic to biofilm state ( Mavrodi et al, 2013 ), show antimicrobial effects against other microorganisms ( Gram, 1993 ), protect cells from oxidative stress and can act as signaling molecules and virulence factors ( Reverchon et al, 2002 ; Dietrich et al, 2006 ; Liu and Nizet, 2009 ). Recently, it has been reported that, in non-pathogenic pseudomonads, the synthesis of pigments, peptidases, and biofilm formation increased at low temperature, putatively to overcome the hurdles imposed by cold stress ( Yuan et al, 2018b ; Rossi C. et al, 2018 ; Quintieri et al, 2019a , b ). Some of these biological components also showed a high similarity with those involved in pathogenesis and resistance mechanisms in the opportunistic pathogen P. aeruginosa ( Quintieri et al, 2019b ), although their role in food spoilage pseudomonads is not yet completely clear.…”

Lactic Acid Bacteria Adjunct Cultures Exert a Mitigation Effect against Spoilage Microbiota in Fresh Cheese

“…The increasing demand of low-salt and low-fat cheese requires new hurdle technologies approaches to reduce the spoilage microbial communities along the shelf life, particularly by psychotropic Gram-negative bacteria [ 33 , 34 ] that can also trigger antimicrobial resistances [ 35 ]. To address this issue, this study focused on the characterization of the spoilage microbiota of these dairy products and the appraisal of lactic acid bacteria adjunct cultures in limiting the outgrowth of these undesirable microorganisms and consequently cheese defects.…”

Modelling formation and removal of biofilms in secondary dairy raw materials

“…Different groups of microorganisms can participate in biofilm formation in dairy processing plants. The attention of biofilm researchers is attracted by Pseudomonas psychrophiles, which secrete heat-resistant lipolytic and proteolytic enzymes, and Geobacillus, Brevibacillus, Paenibacillus, Sporosarcina sporeforming bacteria [7][8][9]. Lactic acid microorganisms are also actively involved in biofilm formation [10,11].…”