Sponges (phylum Porifera) are sessile marine filter feeders that have developed efficient defense mechanisms against foreign attackers such as viruses, bacteria, or eukaryotic organisms. Marine sponges are among the richest sources of pharmacologically-active chemicals from marine organisms. It is suggested that (at least) some of the bioactive secondary metabolites isolated from sponges are produced by functional enzyme clusters, which originated from the sponges and their associated microorganisms. More than 5,300 different products are known from sponges and their associated microorganisms, and more than 200 new metabolites from sponges are reported each year. As infectious microorganisms evolve and develop resistance to existing pharmaceuticals, the marine sponge provides novel leads against bacterial, viral, fungal and parasitic diseases. Many marine natural products have successfully advanced to the late stages of clinical trials, as for example ara-A (vidarabine), an anti-viral drug used against the herpes simplex encephalitis virus. This substance is in clinical use for many years. Moreover, a growing number of candidates have been selected as promising leads for extended preclinical assessment, including manzamine A (activity against malaria, tuberculosis, HIV, and others), lasonolides (antifungal activity) and psammaplin A (antibacterial activity). In this review we have surveyed the discoveries of products derived from marine sponges and associated bacteria that have shown in vivo efficacy or potent in vitro activity against infectious and parasitic diseases, including bacterial, viral, fungal and protozoan infections. Our objective was to highlight the substances that have the greatest potential to lead to clinically useful treatments.

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As sessile and filter-feeding metazoans, marine sponges represent an ecologically important and highly diverse component of marine benthic communities throughout the world. It has been suggested that marine sponges are hosts to many microorganisms which can constitute up to 40-60% of its biomass. Recently, sponges have attracted a high interest from scientific community because two important factors. First there is the fact that sponges have a wide range of associated bacteria; and, second, they are a rich source of bioactive substances. Since 1950, a number of bioactive substances with various pharmacological functions have been isolated from marine sponges. However, many of these substances were subsequently shown to be actually synthesized by sponge-associated bacteria. Bacteria associated with marine sponges constitute an interesting source of novel bioactive compounds with biotechnological potential such as antimicrobial substances, enzymes and surfactants. In addition, these bacteria may be biofilm forming and can act as bioindicators in bioremediation processes of environmental pollution caused by oil and heavy metals. This review focuses on the biotechnological applications of these microorganisms.

Here, we transcriptionally and phenotypically characterized the clpB gene from Enterococcus faecalis. Northern blot analysis identified a monocistronic mRNA strongly induced at 48 and 50 6C. In silico analysis identified that the clpB gene encodes a protein of 868 aa with a predicted molecular mass of approximately 98 kDa, presenting two conserved ATP-binding domains. Sequence analysis also identified a CtsR-binding box upstream of the putative "10 sequence, and inactivation of the ctsR gene resulted in an approximately 2-log increase in clpB mRNA expression, confirming ClpB as a member of the CtsR regulon. While expression of clpB was induced by heat stress, a DclpB strain grew relatively well under many different stressful conditions, including elevated temperatures. However, expression of ClpB appears to play a major role in induced thermotolerance and in pathogenesis, as assessed by using the Galleria mellonella virulence model.

Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

The genus Vibrio comprises pathogens ubiquitous to marine environments. This study evaluated the cultivable Vibrio community in the Guanabara Bay (GB), a recreational, yet heavily polluted estuary in Rio de Janeiro, Brazil. Over one year, 66 water samples from three locations along a pollution gradient were investigated. Isolates were identified by MALDI-TOF mass spectrometry, revealing 20 Vibrio species, including several potential pathogens. Antimicrobial susceptibility testing confirmed resistance to aminoglycosides, beta-lactams (including carbapenems and third-generation cephalosporins), fluoroquinolones, sulfonamides, and tetracyclines. Four strains were producers of extended-spectrum beta-lactamases (ESBL), all of which carried beta-lactam and heavy metal resistance genes. The toxR gene was detected in all V. parahaemolyticus strains, although none carried the tdh or trh genes. Higher bacterial isolation rates occurred in months marked by higher water temperatures, lower salinities, and lower phosphorus and nitrogen concentrations. The presence of non-susceptible Vibrio spp. was related to indicators of eutrophication and sewage inflow. DNA fingerprinting analyses revealed that V. harveyi and V. parahaemolyticus strains non-susceptible to antimicrobials might persist in these waters throughout the year. Our findings indicate the presence of antimicrobial-resistant and potentially pathogenic Vibrio spp. in a recreational environment, raising concerns about the possible risks of human exposure to these waters.

Ionic and organic forms of mercury (Hg) are powerful cytotoxic and neurotoxic agents in both humans and wild life. The aim of this study was to analyze the resistance profile and potential detoxification of inorganic and organic forms of Hg of bacteria isolated from marine sponges on the coast of Rio de Janeiro, Brazil. Out of the 1,236 colony forming units associated with eleven species of marine sponges, 100 morphologically different bacterial strains were analyzed in this study. Of these, 21 strains were resistant to Hg, 14 of which were classified as highly resistant because they grew despite exposure to 100 µM HgCl2. Fifteen resistant strains reduced Hg and presented merA in their genomes. The remaining six strains produced biosurfactants, suggesting that they may tolerate Hg by sequestration. Eleven strains grew in the presence of methylmercury. Our results suggest a potential for mercury detoxification by marine sponge-associated resistant bacteria, either through reduction or sequestration, as well as the possibility of bioremediation of toxic waste containing mercury.

Antimicrobial resistance is widely studied and well‐characterized from a clinical perspective. However, considerably less information is available regarding resistance in environmental settings, especially in aquatic habitats. This study presents data regarding the occurrence, distribution and the antimicrobial susceptibility profile of bacteria isolated from Guanabara Bay (GB), a heavily polluted tropical urban estuary and an important tourist attraction in Rio de Janeiro, Brazil. Water samples from sites characterized by growing degrees of pollution were analysed by culture‐dependent methods, revealing the presence of multidrug‐resistant bacteria and clinically relevant indicators of antimicrobial resistance, such as extended‐spectrum beta‐lactamases. Isolates were identified by mass spectrometry, which indicated the presence of potential human pathogens such as Aeromonas spp. and Vibrio spp. Bacteria harbouring beta‐lactam resistance genes were also detected. Although GB is widely used as a recreational and fishing area, there is a substantial knowledge gap regarding the monitoring of antimicrobial resistance and the risk that exposure to these waters poses to public health. Thus, this study reveals new information that calls for better comprehension of antimicrobial resistance in aquatic environments, especially those used for recreational purposes.