Severe fibrinonecrotic enteritis caused by Pseudomonas aeruginosa in a captive monitor lizard (Varanus niloticus).

Pseudomonas aeruginosa is an important pathogen that has been implicated in a number of serious conditions in humans and animals. Studies regarding the efficacy of antimicrobial drugs against virulent strains of P. aeruginosa in human and animal hosts have demonstrated that common therapeutic options are sometimes ineffective. In captive animals, in particular reptiles, literature on this topic is scarce. In this study, a 6-yr-old monitor lizard, Varanus niloticus, died suddenly without previous symptoms. Postmortem examination and bacteriologic analysis of necropsy samples revealed severe fibrinonecrotic enteritis caused by P. aeruginosa. The isolate presented a typical resistance profile, showing resistance to amoxycillin-clavulanic acid, ampicillin, cephotaxime, and sulphamethoxazole-trimethoprim. Virulence characterization demonstrated that the bacterium was able to express hemolysins, DNases, gelatinases, and lipases and had biofilm-forming ability. This study highlights the importance of surveillance for antimicrobial resistance and virulence traits in captive animals, which may present a challenge to practitioners.

Virulence traits and antibiotic resistance among enterococci isolated from Eurasian otter (Lutra lutra).

Enterococci are ubiquitous microorganisms found as part of the normal intestinal microbiota of many animals such as the free-ranging Eurasian otter (Lutra lutra Linnaeus, 1758). In this work, twenty-nine enterococci isolated from fecal samples of Eurasian otters free-living in reservoirs and associated river stretches in South Portugal were identified and typed by conventional/molecular methods and screened for virulence factors and antibiotic resistance. Identification allocated the isolates to the species Enterococcus faecalis (19), E. faecium (9) and E. durans (1) and PCR-fingerprinting revealed their high genomic diversity. Regarding virulence factors, three isolates produced cytolysin and six were gelatinase-positive. Genes ace and acm were detected in five enterococci each, ebpABC in seventeen, gelE in fourteen and cylA in three. All isolates showed resistance patterns and antibiotic resistance genes tet(M) and pbp5 were detected in seventeen isolates each, whereas vanB and vanD were identified in thirteen and five, respectively, being most van-harboring isolates members of E. faecium. The aac(6')-Ie-aph (2″) gene, encoding for gentamicin resistance, was observed in all gentamicin-resistant enterococci. Since all isolates harbor virulence and/or antibiotic resistance traits, the role of free-living Eurasian otters in the dissemination of virulent/resistant enterococci among other animals sharing the same ecological niche cannot be disregarded, as well as the health risk they may represent for humans directly interacting with them or their habitat.

Invasive potential of biofilm-forming Staphylococci bovine subclinical mastitis isolates.

Staphylococcus (S.) aureus is a common infectious agent of bovine chronic mastitis, a disease that is difficult to eradicate. The abilities of staphylococci to be internalized and form a biofilm can contribute to host immunological defence evasion that subsequently impairs antimicrobial therapy. The invasive capability of six S. aureus field isolates with different biofilmforming profiles was compared in vitro using a bovine mammary epithelial cell line. This was further confirmed in primary cell cultures using fluorescent rRNA probes against S. aureus. The results suggest that S. aureus invasion levels are not related to biofilm formation.

Antimicrobial-resistant Salmonella isolated from Eurasian otters (Lutra lutra Linnaeus, 1758) in Portugal.

Eurasian otters (Lutra lutra Linnaeus, 1758) are present in a wide range of aquatic environments. Salmonella isolates have been obtained from otters at rehabilitation centers and in the wild and are sometimes associated with serious illnesses. Antimicrobial-resistant Salmonella were isolated from otter fecal samples collected in March 2006, September 2007, and March 2008 in two river basins in southern Portugal. From 67 samples tested, five were positive for Salmonella (7.58%). None of the isolates were susceptible to all antimicrobials tested, and all were resistant to multiple antimicrobials. Our results confirm the role of otters as potential carriers of Salmonella and the importance of environmental exposure to antimicrobial agents in selection for resistance in bacteria.