Yemen is currently experiencing the largest cholera epidemic in recent history. The first cases were declared in September 2016, and over 1.1 million cases and 2,300 deaths have since been reported1. We investigated the phylogenetic relationships, pathogenesis, and antimicrobial resistance determinants by sequencing the genomes of Vibrio cholerae isolates from the Yemen epidemic and recent isolates from neighbouring regions. These 116 genomic sequences were placed within the phylogenetic context of a global collection of 1087 seventh pandemic V. cholerae serogroup O1 and O139 biotype El Tor isolates [2–4]. We show that the Yemeni isolates collected during the two epidemiological waves of the epidemic [1], —the first between September 28th 2016 and April 23rd 2017 (25,839 suspected cases) and the second beginning on April 24th, 2017 (more than one million suspected cases), — are seventh pandemic V. cholerae O1 El Tor (7PET) serotype Ogawa isolates from a single sublineage. Using genomic approaches, we link the Yemen epidemic to global radiations of pandemic V. cholerae and show that this sublineage originated from South Asia and that it caused outbreaks in East Africa before appearing in Yemen. We also show that the Yemeni isolates are susceptible to several antibiotics commonly used to treat cholera, and to polymyxins, resistance to which is used as a marker of the El Tor biotype.

An oxygen nanoshuttle based on a reduced graphene oxide/copper peroxide (rGO/CuO 2 ) nanocomposite has been presented to deliver in situ oxygen nanobubbles (O 2 NBs) for combating bacterial infections. In the presence of rGO, the solid source of oxygen (i.e., CuO 2 ) was decomposed (in response to environmental conditions such as pH and temperature) into O 2 NBs in a more controllable and long-lasting trend (from 60 to 144 h). In a neutral buffer, the O 2 NBs experienced growth and collapse evolutions, creating a dynamic micro− nanoenvironment around the nanocomposite. In addition to effective battling against methicillin-resistant Staphylococcus aureus bacteria, the O 2 NBs demonstrated superior antibacterial properties on Gram-positive S. aureus to those on Gram-negative Escherichia coli bacteria, especially in the presence of rGO. In fact, the rGO contents could provide synergistic effects through harvesting some respiratory electrons (leading to striking interruption of the bacterial respiratory pathway) in one side and transferring them into the O 2 NBs, resulting in nanoscale reactive oxygen species (ROS) generation in another side. Moreover, nearinfrared laser irradiation induced more damage to the cell membrane due to the synergistic effects of local heat elevation and catalyzing the release/collapse of NBs imposing mechanical disruptions. Our results show that the O 2 -containing nanoshuttles can effectively be used as intelligent and controllable anti-infection nanorobots in upcoming graphene-based nanobiomedical applications.

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In this study, 50 Vibrio cholerae O1 serotype Inaba isolates were collected during several cholera outbreaks throughout Iran during the summer of 2005. The results of antibiotic susceptibility testing showed that 86, 84, 84 and 82 % of the isolates were resistant to streptomycin, chloramphenicol, co-trimoxazole and tetracycline, respectively. The strains were genotyped using randomly amplified polymorphic DNA (RAPD), PFGE and ribotyping techniques. PCR showed that 100, 98 and 98 % carried the ctx, zot and ace genes, respectively. Biochemical fingerprinting of the isolates using the PhenePlate (PhP) system showed a low diversity index level (0.755), suggesting that the strains were highly homogeneous. Among the strains, 100 and 96 % showed an identical ribotype and PFGE patterns, respectively. The two isolates showing different PFGE patterns also exhibited discrete PhP types. RAPD was able to discriminate the isolates into six distinct groups, suggesting some genetic dissimilarity was present among the strains. These ribotyping, PFGE and PhP techniques revealed the clonal dissemination of a single V. cholerae strain throughout Iran in 2005.

Our results showed a correlation between presence of virulence gene and antibiotic resistance in K. pneumoniae.

Bioactive glasses (BGs) have attracted added attention in the structure of the scaffolds for bone repair applications. Different metal ions could be doped in BGs to induce specific biological responses. Among these ions, strontium (Sr) is considered as an effective and safe doping element with promising effects on bone formation and regeneration. In this experiment, we evaluated the antibacterial activities of the gelatin-BG (Gel-BG) and Gel-BG/Sr scaffolds in vitro. The osteogenic properties of the prepared scaffolds were also assessed in rabbit calvarial bone defects for 12 weeks. Both scaffolds showed in vivo bone formation during 12 weeks with the newly formed bone area in Gel-BG/Sr scaffold was higher than that in Gel-BG scaffolds after the whole period. Based on the histological results, Gel-BG/Sr exhibited acceleration of early-stage bone formation in vivo. The results of antibacterial investigation for both scaffolds showed complete growth inhibition against Escherichia coli (E. coli). Although Gel-BG revealed no antibacterial effect on Staphylococcus aureus (S. aureus), the Gel-BG/Sr was able to partially inhibit the growth of S. aureus, as detected by threefold reduction in growth index. Our results confirmed that Sr doped BG is a favorable candidate for bone tissue engineering with superior antibacterial activity and bone regeneration capacity compared with similar counterparts having no Sr ion.

Class 2 integrons were found to be predominant among our Shigella spp. This reflects the need to monitor the acquisition and dissemination of different resistant gene cassettes among integrons. Comparison of PFGE pattern through standard procedures promoted the molecular epidemiological surveys and identification of clonal isolates in Iran and other Asian countries.

Genotypic and phenotypic characterizations of 50 clinical Vibrio cholerae isolates obtained during 4 consecutive y from 2004 to 2007 in Iran were studied. Antimicrobial susceptibility test, biochemical fingerprinting with Phene Plate system (PhP-RV) and pulsed-field gel electrophoresis (PFGE) were performed. Antibiotic susceptibility test of all isolates showed 12 different profiles. The predominant antimicrobial resistance profile (62%) was simultaneous resistance to SXT, streptomycin, chloramphenicol and erythromycin. PFGE revealed a total of 9 pulsotypes with a single dominant type in each y under study. PhP-RV revealed 6 common and 10 single types constituting 80% and 20% of the isolates, respectively. Diversity index of PhP-RV was 0.853, indicative of homogeneity among the isolates. Data obtained from PhP-RV was in close agreement with the results of PFGE genotyping. A comparison of the published PFGE patterns performed using the PulseNet protocol revealed the presence of similar patterns between some of our isolates and the isolates from Pakistan, Nepal and India, suggestive of dissemination of common V. cholerae clones in this region of the world. This could, in part, be due to human travel or occurrence of analogous DNA rearrangements, resulting in the emergence of similar V. cholerae genotypes in regional countries.