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Aim To evaluate an antibiotic inactivation strategy to protect the gut microbiome from antibiotic-mediated damage. Methods and Results SYN-004 (ribaxamase) is an orally delivered beta-lactamase intended to degrade penicillins and cephalosporins within the gastrointestinal tract to protect the microbiome. Pigs (20 kg, n = 10) were treated with ceftriaxone (CRO) ( IV, 50 mg kg−1, SID) for 7 days and a cohort ( n = 5) received ribaxamase ( PO, 75 mg, QID) for 9 days beginning the day before antibiotic administration. Ceftriaxone serum levels were not statistically different in the antibiotic-alone and antibiotic + ribaxamase groups, indicating ribaxamase did not alter systemic antibiotic levels. Whole-genome metagenomic analyses of pig faecal DNA revealed that CRO caused significant changes to the gut microbiome and an increased frequency of antibiotic resistance genes. With ribaxamase, the gut microbiomes were not significantly different from pretreatment and antibiotic resistance gene frequency was not increased. Conclusion Ribaxamase mitigated CRO-mediated gut microbiome dysbiosis and attenuated propagation of the antibiotic resistance genes in pigs. Significance and Impact of the Study Damage of the microbiome can lead to overgrowth of pathogenic organisms and antibiotic exposure can promote selection for antibiotic-resistant micro-organisms. Ribaxamase has the potential to become the first therapy designed to protect the gut microbiome from antibiotic-mediated dysbiosis and reduce emergence of antibiotic resistance. [ABSTRACT FROM AUTHOR]

Paranaguá Bay is one of the largest estuarine systems on the Southern Brazilian coast. The only recorded cholera outbreak in this region since the early 20th century occurred in 1999 and resulted in 467 cases and at least three reported deaths in a population of approx. 150 000 people. This short communication reports historical, unpublished data related to that outbreak. Water, zooplankton and bivalve samples were collected and evaluated using direct fluorescence assay to determine whether Vibrio cholerae serogroups O1 and O139 were present in the estuarine system at that time. Most of the water (83%) and zooplankton samples (75%) were positive for V. cholerae O1, while V. cholerae O139 was not detected. Shellfish (Mytella sp.) were also positive for V. cholerae O1. These results indicate that the estuary, including biological vectors such as copepods and bivalves, comprise an important reservoir of V. cholerae O1 and a probable waterborne pathway for the disease, in addition to contamination with untreated sewage. [ABSTRACT FROM AUTHOR]

Abstract Aims: The study was undertaken with the objective of understanding the virulence-associated genes of the CTX and TCP gene clusters in environmental isolates of Vibrio cholerae , an important human pathogen, isolated from the aquaculture environment. The involvement of the omp U gene in conferring bile resistance in these isolates was also evaluated. Methods and Results: The V. cholerae isolates were tested by PCR and fluorescent antibody test for O1 (Ogawa and Inaba) and O139 serotypes. All isolates were found to be non-toxigenic V. cholerae confirmed by their positive PCR reaction for tox R but negative for ctx , zot and tcp gene. The hly A gene was detected in 85% of the strains and omp U in 77%. The results on the bactericidal effect of bile salts suggest that omp U may play a role in conferring bile resistance in non-O1/non-O139 strains. Conclusion: The results of the study indicate that most environmental strains lacked the CTX and TCP gene clusters. However, most isolates had the hly A gene indicating the potential of these environmental strains to cause mild gastroenteritis. It was also observed that strains lacking omp U showed less tolerance to bile salts. Significance and Impact of the Study: Information on virulence factors of V. cholerae associated with aquaculture environment and products would be of value in risk assessment for human health. [ABSTRACT FROM AUTHOR]

Aims: Physiological responses of marine luminous bacteria, Fibrio harveyi (ATCC 14216) and F. fischeri (UM1373) to nutrient-limited normal strength (35 ppt iso-osmolarity) and low (10 ppt hypo-osmolarity) salinity conditions were determined. Methods and Results: Plate counts, direct viable counts, actively respiring cell counts, nucleoid-containing cell counts, and total counts were determined. Fibrio harveyi incubated at 22°C in nutrient-limited artificial seawater (ASW) became nonculturable after approximately 62 and 45 d in microcosms of 35 ppt and 10 ppt ASW, respectively. In contrast, F. fischeri became nonculturable at approximately 55 and 31 d in similar microcosms. Recovery of both culturability and luminescence of cells in the viable but nonculturable state was achieved by addition of nutrient broth or nutrient broth supplemented with a carbon source, including luminescence-stimulating compounds. Temperature upshift from 22°C to 30°C or 37°C did not result in recovery from nonculturability. Conclusions: The study confirms entry of F. harveyi and F. fischeri into the viable but nonculturable state under low-nutrient conditions and demonstrates nutrient-dependent resuscitation from this state. Significance and Impact of the Study: This study confirms loss of luminescence of F. harveyi and F. fischeri on entry into the viable but nonculturable state and suggests that enumeration of luminescent cells in water samples may be a rapid method to deduce the nutrient status of a water sample. [ABSTRACT FROM AUTHOR]

Aims: This study was carried out to investigate the occurrence of potentially pathogenic species of Vibrio in French marine and estuarine environments. Methods and Results: Samples of coastal waters and mussels collected between July and September 1999 were analysed by culture, using selective media including thiosulphate-citratebile salts-sucrose and modified cellobiose-polymixin B-colistin agar. Presumptive Vibrio colonies were isolated and identified using selected biochemical tests. Specific primers based on flanking sequences of the cytolysin, vvhA gene, pR72H DNA fragment and 16S-23S rRNA intergenic spacer region (ISR) were used in a polymerase chain reaction (PCR) to confirm the identification of Vibrio vulnificus, V. parahaemolyticus and V. cholerae, respectively. In this study, V. alginolyticus (99 of 189) was the predominant species, followed by V. parahaemolyticus (41 of 189), V. vulnificus (20 of 189) and non-O1/non-O139 V. cholerae (three of 189). All 20 V. vulnificus isolates showed PCR amplification of the vvhA gene, 16 of which had been isolated from estuarine water. The PCR amplification of the pR72H DNA fragment in 41 V. parahaemolyticus isolates generated two unique amplicons of 387 and 320 bp. The latter, present in 24&middot4% of these isolates, had not previously been found in V. parahaemolyticus strains examined to date. Amplification of the trh gene in two of the isolates suggested these to be virulent strains. Three strains identified as V. cholerae by amplification of the 16S-23S rRNA ISR were confirmed to be non-cholera (non-O1/non-O139) strains. Conclusions: The results of this study demonstrated the presence of pathogenic Vibrio species in French coastal waters. Furthermore, the PCR approach proved useful for the rapid and reliable confirmation of species identification. Significance and Impact of the Study: These findings indicate the potential sanitary risk associated with the presence of pathogenic Vibrio spp. in cultivated... [ABSTRACT FROM AUTHOR]

An environmental source of cholera was hypothesized as early as the late nineteenth century by Robert Koch, but not proven because of the ability of Vibrio cholera, the causative agent of cholera, to enter a dormant phase between epidemics. Standard bacteriological procedures for isolation of the vibrios from the environmental samples, including water, between epidemics generally were unsuccessful. Vibrio cholera, a marine vibrio requiring salt for growth, enters into a dormant 'viable but non-culturable' stage when conditions are unfavourable for growth and reproduction. The association of V. cholera with plankton, notably copepods, provides evidence for the environmental origin of cholera, as well as an explanation for the sporadic and erratic nature of cholera epidemics. Thus, the association of V. cholera with plankton was established only recently, allowing analysis of epidemic patterns of cholera, especially in those countries where cholera is endemic. The sporadic and erratic nature of cholera epidemics can now be related to climate and climate events, such as El Niño. Since zooplankton have been shown to harbour the bacterium and zooplankton blooms follow phytoplankton blooms, remote sensing can be employed to determine the relationship of cases of cholera with chlorophyll, as well as sea surface temperature (SST), ocean height, and turbidity. Cholera occurs seasonally in Bangladesh with two annual peaks in the number of cases occurring each year. From the data obtained and analysed to date, when the height of the ocean is high and sea surface temperature is also elevated, cholera cases are numerous. When the height is low and sea surface temperature is also low, little or no cholera is recorded. From the examination of data for the 1992-1993 cholera epidemic in India, preliminary comparisons of cholera data for Calcutta show a similar relationship between cholera cases, ocean height and SST. In conclusion, from results of studies of SST,... [ABSTRACT FROM AUTHOR]