Diversity of Bacterial Biofilm Communities on Sprinklers from Dairy Farm Cooling Systems in Israel

Abstract

On dairy farms in hot climates worldwide, cows suffer from heat stress, which is alleviated by the use of water cooling systems. Sprinklers and showerheads are known to support the development of microbial biofilms, which can be a source of infection by pathogenic microorganisms. The aim of this study was to investigate the presence of microbial biofilms in dairy cooling systems, and to analyze their population compositions using culture-independent technique, 16S rRNA gene sequencing. Biofilm samples were collected on eight dairy farms from 40 sprinklers and the microbial constituents were identified by deep sequencing of the 16S rRNA gene. A total of 9,374 operational taxonomic units (OTUs) was obtained from all samples. The mean richness of the samples was 465 ± 268 OTUs which were classified into 26 different phyla; 76% of the reads belonged to only three phyla: Proteobacteria, Actinobacteria and Firmicutes. Although the most prevalent OTUs (Paracoccus, Methyloversatilis, Brevundimonas, Porphyrobacter, Gp4, Mycobacterium, Hyphomicrobium, Corynebacterium and Clostridium) were shared by all farms, each farm formed a unique microbial pattern. Some known potential human and livestock pathogens were found to be closely related to the OTUs found in this study. This work demonstrates the presence of biofilm in dairy cooling systems which may potentially serve as a live source for microbial pathogens.

The cooling tower water microbiota: Seasonal dynamics and co-occurrence of bacterial and protist phylotypes

“…They are considered pioneers, specifically facilitating the initiation of biofilm formation (Douterelo et al., 2014). Members of the genus Methyloversatilis are found in various environments including drinking water and biofilms (Kalyuzhnaya et al., 2006; Liu et al., 2012; Shpigel et al., 2015; van der Kooij et al., 2017; Williams et al., 2004). Blastomonas species have the ability to coaggregate with various bacteria, an important feature for biofilm formation (Katharios-Lanwermeyer et al., 2014; Rickard et al., 2002).…”

Bacterial community composition of biofilms in milking machines of two dairy farms assessed by a combination of culture-dependent and –independent methods

“…The microbiota of udders and of the stable environment have already been described as sources for raw milk contamination [12, 17]. Dairy biofilms have been analyzed in sprinklers from dairy farm cooling systems [19], raw milk pipelines on dairy farms [20], raw milk cooling tanks [21], raw milk road tankers [10] and in dairy processing plants [8, 22, 23] so far. Many studies focus on the detection of pathogens, like Listeria monocytogenes [24], or on other prominent milk associated bacterial genera [25].…”

Pseudomonas fluorescens: a potential food spoiler and challenges and advances in its detection

“…Biofilm formation by P. fluorescens P. fluorescens has been regarded as the predominant and most harmful microbiota during the cold storage of raw milk (Machado et al 2015;Von-Neubeck et al 2015;Vithanage et al 2016). During storage of the dairy product, not only the P. fluorescens heat-resistant enzymes will remain active after heat sterilization, causing milk bitterness, sediment, and gelation, but they also form biofilm on the surface of equipments and tools in dairy production line (Shpigel et al 2015;Stoeckel et al 2016). Once the biofilm is formed by the Pseudomonas bacteria, it is hard to remove it by the hygienic treatments during the processing of raw milk (Ksontini et al 2013).…”