Spiroplasma spp.: A Plant, Arthropod, Animal and Human Pathogen

Mollicutes is a class of smallest and free-living bacteria. They have no cell wall and their plasma membrane contains cholesterol; nevertheless, cellular organization does not differ from that of other prokaryotes. They are used as simple model systems for studying general biological problems, such as those concerning membrane structure and functions, symbiosis between arthropods and microrganisms, animal and plant pathogens. Mollicutes includes the family of Spiroplamataceae, which contains Spiroplasma genus, a group of species associated, in different manner, with arthropods (insects, mites, crustaceans). Spiroplasma species can be commensals or parasites and even be involved in more close symbiosis, such as synergism or mutualism. Out of 38 described Spiroplasma species, only three have been associated with plant diseases and three with arthropod diseases. Moreover, some species have been related to animal diseases, such as transmissible spongiform encephalopathy (TSE), and their role in human disease has been assessed. The chapter describes the taxonomic situation of the genus and reports the most important diseases due to the presence of Spiroplasma in different living organisms with special emphasis on citrus in which it causes one of the most economically damaging infectious diseases in a number of citrus growing areas worldwide

Evaluation of resistance to low pH and bile salts of human Lactobacillus spp. isolates

There are nearly 100 trillion bacteria in the intestine that together form the intestinal microbiota. They are 'good' bacteria because they help to maintain a physiological balance and are called probiotics. Probiotics must have some important characteristics: be safe for humans, be resistant to the low pH in the stomach, as well as bile salts and pancreatic juice. Indeed, their survival is the most important factor, so that they can arrive alive in the intestine and are able to form colonies, at least temporarily. The aim of our study was the evaluation of resistance of Lactobacillus isolates from fecal and oral swabs compared to that found in a commercial product. Seven strains were randomly chosen: L. jensenii, L. gasseri, L. salivarius, L. fermentum, L. rhamnosus, L. crispatus, and L. delbrueckii. We observed a large variability in the results: L. gasseri and L. fermentum were the most resistance to low pH, while only L. gasseri showed the best survival rate to bile salts. Interestingly, the commercial product did not show tolerance to both low pH and bile salts

ENDOSYMBIONTS OF ENTOMOPATHOGENIC NEMATODES FROM SOUTH ITALY:A PHENOTYPIC STUDY

We examined different Xenorhabdusstrains (five of X. bovieniiand two of X. kozodoii), obtained from EPNisolates belonging to the genus Steinernema(S. feltiae, S. ichnusae, S. apuliae, S. vulcanicum) of different geographicorigin by both genotypic and phenotypic analysis. Common laboratory assays were done for traits such as antibioticresistance, haemolytic activity, lactose utilisation, biofilm production, chosen as the least selectable traits for EPN life-cycle, and thus as (presumably) neutral traits. As selective marker, the activity of the endosymbiont’s toxins was verified inan in vivoassay on G. mellonellalarvae. Genotyping done by 16S partial sequencing was used for identification purposes.Xenorhabdusbovieniiisolates showed a broad phenotypic spectrum; on the other hand, X. kozodoiishowed a less degreeof phenotypic variation, reduced ability of biofilm production and conspicuous β-galactosidase activity. However, all thestrains were able to kill G. mellonellalarvae with high efficiency

In Vitro Efficacy of Crataegus oxycantha L. (Hawthorn) and Its Major Components against ATCC and Clinical Strains of Ureaplasma urealyticum

Abstract Crataegus oxycantha L., commonly known as hawthorn, has traditionally been used for its beneficial effect on cardiovascular health, which is related to its flavonoid content. The aim of the present study was to evaluate the antibacterial properties of a fluid extract and a hydro-ethanolic macerate from buds of Crataegus oxycantha against clinical isolates of Ureaplasma urealyticum. The major purified flavonoids present in the extracts were also tested against ATCC strains and clinical isolates. Both the fluid extract and the hydro-ethanolic macerate were active against thirty-due clinical strains of U. urealyticum, with MIC ranges between 15.6 and 250 μg/ml and 15.6 and 62.5 μg/ml, respectively. All pure organic compounds, with the exception of rutin, showed activity against the strains tested, luteolin 3,7-diglucoside being the most active compound (MICs in the range of 0.48 and 1.95 μg/ml), followed by apigenin-7-O-glucoside (MICs in the range of 0.48 and 3.9 μg/ml). The activity of the pure flavonoids was greater against the clinical isolates compared to the ATCC strains. The data presented here demonstrate that flavonoids present in Crataegus oxycantha are effective against clinical isolates of U. urealyticum and could be used in combination with antibiotics in order to combat resistance

Isolamento e caratterizzazione di Streptococcus agalactiae in donne gravide

Negli ultimi decenni lo Streptococcus agalactiae (GBS) ha assunto un ruolo prioritario nel determinismo delle infezioni neonatali, con un alto tasso di mortalità. Nel presente studio è stata valutata la frequenza della colonizzazione materna, la distribuzione sierotipica, l’efficacia della chemioprofilassi intrapartum e l’epidemiologia molecolare di alcuni fattori di virulenza di GBS. In particolare, sui ceppi è stato svolto uno studio per identificare i geni codificanti per le proteine di superficie alp, la produzione di biofilm, la valutazione della sensibilità ad alcuni antibiotici e i geni di resistenza ai macrolidi. Sono state studiate 60 donne gravide tra la 35ª-37ª settimana alle quali in corso di screening per la prevenzione della malattia perinatale da GBS, è stato effettuato un doppio tampone, vaginale e rettale. Il 12% delle gravide arruolate è risultato colonizzato da GBS ed i sierotipi identificati sono stati Ia, III e V. Le proteine “alp” sono espresse nel 72% dei ceppi isolati. La maggiore produzione di biofilm si è ottenuta su terreno di coltura THB addizionato all’1% di glucosio in condizioni di 5% di CO2. Tutti i ceppi isolati si sono dimostrati sensibili all’ampicillina, ma il 28,5% si è dimostrato resistente alle altre classi di antibiotici saggiati (macrolidi e lincosamidi). Tutte le donne colonizzate sono state sottoposte alla chemioprofilassi intrapartum; il decorso fisiologico ed afebbrile del puerperio e, soprattutto, la mancanza di manifestazioni nei neonati delle donne sottoposte a trattamento dimostra l’efficacia della procedura

Lactobacillus rhamnosus AD3 as a Promising Alternative for Probiotic Products

Lactobacillus strains dominate the vaginal habitat and they are associated with a lower risk of genital infections. In addition, they contribute to the conservation of the vaginal microbiota by producing postbiotic agents. Previous studies have shown that their predominance involves antimicrobial activity against urogenital pathologies. In this context, probiotics may improve treatment outcomes. The aim of this study was to evaluate the probiotic properties of lactobacilli strains of vaginal origin using a multidisciplinary approach. For this purpose, safety criteria, ability to resist at low pH and bile salts, antimicrobial activity, ability to produce biofilm, capacity to produce hydrogen peroxide and more importantly, auto-aggregation, co-aggregation (with Candida spp.) and adhesion to human cells were evaluated. The strains belonged to the species of L. crispatus, L. gasseri, L. rhamnosus and L. delbruckii. Among these, a strain of L. rhamnosus named AD3 showed the best probiotic properties. As probiotics are already in use in many clinical practice and there are no major safety concerns, L. rhamnosus AD3 showed promise in becoming a prevention and complementary treatment option for urogenital diseases. Indeed, these results suggest that strain L. rhamnosus AD3 is non-pathogenic and likely to be safe for human consumption. This study revealed the great amensalistic properties of a new L. rhamnosus strain which can aim to be used as probiotic in pharmaceutical applications

Colistin and kanamycin together in association with Coridothymus capitatus to enhance their antimicrobial activity and fight multidrug resistance pathogens

It should be remembered that bacteria continue to spread and develop new types of resistance, so further actions are needed to deal with antibiotic resistance. As a result, antibacterial drugs have become less effective, resulting in the accelerated discovery of available alternative treatments, including essential oils. The aim of this work was to intensify and promote the action of two antibiotics, kanamycin, and colistin, to fight antibiotic resistance thanks to the action of essential oil obtained from the flowers of Coridothymus capitatus grown on the Iblei mountains. To this end, a comparison of biological and chemical assays was carried out. The results showed a broad antimicrobial power of the essential oil itself and a great synergistic activity in combination with Kanamycin and Colistin against multidrug-resistant bacteria. These combinations increased the range of antibiotics, leading us to speculate that it could be incorporated into new pharmaceutical formulations for therapies of infections caused by increasingly dangerous bacteria. Antibiotic resistance represents an ever-greater danger to human health. This work re-evaluates the use of colistin and kanamycin thanks to the synergistic action found with the addition of a natural substance to pave the way for new therapeutic strategies

Antimycoplasmal Activity of Hydroxytyrosol

The aim of this study was to investigate the in vitro antimycoplasmal activity of hydroxytyrosol. Twenty strains of Mycoplasma hominis, three strains of Mycoplasma fermentans, and one strain of Mycoplasma pneumoniae were used. For M. pneumoniae, M. hominis, and M. fermentans, the MICs were 0.5, 0.03 (for 90% of the strains tested), and 0.25 μg/ml, respectively