Ultrastructural changes in fin epithelium of Channa punctatus (Bloch) exposed to mercuric chloride: sem study.

Fish skin is in direct contact with water and forms the first line of defense against pathogens and toxicants present in the surrounding water. The effect of mercuric chloride (HgCl2) on surface architecture of the epidermis of caudal fin of an air breathing fish, Channa punctatus was examined by scanning electron microscopy (SEM) and revealed the presence of microridges that formed intricate, maze-like patterns. The exposed fish showed significant alterations including disorganization of microridge pattern and increase in number as well as enlargement of mucus cell openings. These findings exhibited concentration- and time- dependent alterations in fin epithelium. Data demonstrated that fin epithelium of fish may be successfully employed as a bioindicator of water pollution.

Indwelling device use and antibiotic resistance in nursing homes: identifying a high-risk group.

OBJECTIVES: To quantify the relationship between indwelling devices (urinary catheters, feeding tubes, and peripherally inserted central catheters) and carriage of antimicrobial-resistant pathogens in nursing home residents. DESIGN: Cross-sectional. SETTING: Community nursing home in Southeast Michigan. PARTICIPANTS: Residents with indwelling devices (n=100) and randomly selected control residents (n=100) in 14 nursing homes. MEASUREMENTS: Data on age, functional status, and Charlson comorbidity score were collected. Samples were obtained from nares, oropharynx, groin, wounds, perianal area, and enteral feeding tube site. Standard microbiological methods were used to identify methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and ceftazidime-resistant (CTZ-R) gram-negative bacteria (GNB). RESULTS: Use of indwelling devices was associated with colonization with MRSA at any site (odds ratio (OR)=2.0, P=.04), groin (OR=4.8, P=.006), and perianal area (OR=3.6, P=.01) and CTZ-R GNB at any site (OR=5.6, P=.003). Use of enteral feeding tubes was associated with MRSA colonization in the oropharynx (OR=3.3, P=.02). CONCLUSION: Use of indwelling devices is associated with greater colonization with antimicrobial-resistant pathogens. This study serves as an initial step in defining a high-risk group that merits intensive infection control efforts.