This study confirms previous suggestions on transduction in enterococci, in particular on interspecies transduction. Interspecies transduction is significant because it widens the range of recipients involved in antimicrobial resistance transfer.

Bacterial diversity in sediments at UNESCO World Heritage listed Naracoorte Caves was surveyed as part of an investigation carried out in a larger study on assessing microbial communities in caves. Cave selection was based on tourist accessibility; Stick Tomato and Alexandra Cave (> 15000 annual visits) and Strawhaven Cave was used as control (no tourist access). Microbial analysis showed that Bacillus was the most commonly detected microbial genus by culture dependent and independent survey of tourist accessible and inaccessible areas of show (tourist accessible) and control caves. Other detected sediment bacterial groups were assigned to the Firmicutes, Actinobacteria and Proteobacteria. The survey also showed differences in bacterial diversity in caves with human access compared to the control cave with the control cave having unique microbial sequences (Acinetobacter, Agromyces, Micrococcus and Streptomyces). The show caves had higher bacterial counts, different 16S rDNA based DGGE cluster patterns and principal component groupings compared to Strawhaven. Different factors such as human access, cave use and configurations could have been responsible for the differences observed in the bacterial community cluster patterns (tourist accessible and inaccessible areas) of these caves. Cave sediments can therefore act as reservoirs of microorganisms. This might have some implications on cave conservation activities especially if these sediments harbor rock art degrading microorganisms in caves with rock art.Keywords: caves; tourism; 16S rDNA; denaturing gradient gel electrophoresis factors attracting tourists (Russell & MacLean, 2008;Bastian et al., 2009; Stomeo et al., 2009).Cave microorganisms range from bacterial groups such as Proteobacteria, Actinobacteria, and Firmicutes to yeasts and saprophytic fungus such as Penicillium, Fusarium and Trichurus (Barton & Jurado, 2007;Zhou et al., 2007;Bastian et al., 2009;Portillo et al., 2009a; Jurado et al., 2010; Adetutu et al., 2011; Vaughan et al., 2011). These microbial communities are affected by the geological nature of the caves, prevailing environmental conditions, soil or sediment factors and cave factors (configuration and use) (Ikner et al., 2007; Shapiro & Pringle, 2010; Adetutu et al., 2011). Cave microorganisms in nutrient rich or limited environments (high and low energy caves) are metabolically versatile acquiring energy from cave compounds, gases and by oxidizing metals from rocks. Through these activities, these microorganisms play critical roles in caves' biogeochemical cycles and in the formation of cave features such as stalactites and stalagmites (Barton & Jurado, 2007). This delicate microbial balance can however be disrupted by uncontrolled human access with adverse effects on the cave environment (Bastian et al., 2010).Abstract:

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Most of the bacteriophages (phages) currently reported in Enterococcus spp. belong to tailed families of bacteriophages Podoviridae, Siphoviridae, and Myoviridae. There is a little information on non-tailed bacteriophages isolated from enterococci. Samples of sewage and piggery effluents were tested on pig and chicken isolates of Enterococcus faecalis, E. faecium and E. gallinarum for lytic phages. In addition, isolates were exposed to mitomycin C to induce lysogenic phages. Bacteriophages that were detected were visualized by electron microscopy. Ten bacteriophages were of isometric shape with long flexible or non-flexible tails, while one had a long head with a long flexible tail; all contained double-stranded DNA molecules. Seven Polyhedral, filamentous, and pleomorphic-shaped phages containing DNA or RNA were also observed. The pleomorphic phages were droplet- or lemon-shaped in morphology. This study is the first report on polyhedral phages in Enterococcus spp. of animal origin and also the first report of filamentous and pleomorphic phages in enterococci.

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Bacteriophages contribute greatly to bacterial evolution. There has been limited investigation of enterococcal bacteriophages, and only two enterococcal bacteriophages have been sequenced completely. In this study, a novel enterococcal bacteriophage, EFRM31, was isolated from a piggery effluent sample and then characterized. The complete bacteriophage genome was determined by shotgun sequencing. EFRM31 belongs to the family Siphoviridae (order Caudovirales) and has a circular double-stranded DNA genome. The putative EFRM31 genome consists of 16945 nucleotides with a low GC content (34.5%) and does not contain CpG islands. The EFRM31 genome contains 82 putative open reading frames, including 17 with identities to genes required for the assembly of a head-tail bacteriophage and 6 hypothetical proteins of unknown function. In general, the sequencing results from EFRM31 revealed considerable similarity to another enterococcal bacteriophage, EFAP-1. This identity and the order of shared genes suggest a close relationship or a common ancestor for these two bacteriophages.

Introduction Acinetobacter baumannii are nosocomial bacteria that are responsible for outbreaks and severe infections in hospitalized patients globally. The major target of this study was the characterization of virulence determinants and biofilm formation of A. baumannii isolates from hospitalized patients. Methods In total, 100 A. baumannii were collected from three hospitals in Tehran, Iran, 2017-2018. The isolates were assessed using phenotypic and genotypic methods and then screened for virulence factor encoding genes such as plcN and lasB using conventional polymerase chain reaction. Furthermore, bacterial biofilm formation, motility and hemolytic and proteolytic activities were assessed. Results Of 100 A. baumannii isolates, 20 isolates included plcN and four isolates included lasB using PCR assay. Overall, 21 isolates were negative for biofilm formation while 45, 20 and 14 of the total isolates were reported as weak, moderate and strong biofilm producers, respectively. All isolates were positive for bap genes using PCR. Moreover, 35 isolates were motile on Luria-Bertani media, 47 isolates were αhemolytic on Brucella blood agar media and all isolates displayed proteolytic activity. Conclusions Healthcare-associated infections with A. baumannii are a major concern, importantly due to their potency to acquire virulence factor genes. Therefore, shedding light in the discovery of new antimicrobial and/or therapeutic agents against virulent A. baumannii strains seem to be necessary.

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