Antimicrobial peptides: a potential role in ocular therapy

Bacterial pathogens are often involved in contact lens‐related adverse responses. This study aimed to find antimicrobial peptides and proteins that effectively eradicate or inhibit ocular bacteria. The antimicrobials were screened against Gram‐ negative and Gram‐positive bacteria originating from ocular sources. The viability of these ocular bacteria was measured after exposure to the peptides and proteins. Two conditions were used to grow bacteria, low nutrient phosphate‐buffered saline and high nutrient tryptone soya broth. Samples were taken at different times up to 48 h. In low nutrient conditions, protamine was found to be the most effective against all strains. Melittin was very effective against all strains except Serratia and one Pseudomonas isolate which were partially affected. In high nutrient condition, only melittin was effective in killing Staphylococcus aureus. Protamine and the combination of protamine and melittin had the greatest effect in eradicating the bacteria tested in low nutrient condition. Protamine alone and its combination with melittin may have potential therapeutic agents for ocular infections in an era of emerging antibiotic resistance.     

Production of N-acyl homoserine lactones by Gram-negative bacteria isolated from contact lens wearers

The purpose of this study was to investigate the production of N‐acyl‐homoserine lactone (AHL) signal molecules in ocular Gram‐negative bacteria. A total of 91 ocular strains isolated from contact lens adverse response patients and asymptomatic subjects were used in the study. These included Acinetobacter, Aeromonas hydrophila, Escherichia coli, Haemophilus influenzae, Klebsiella oxytoca, Pseudomonas aeruginosa, Serratia liquefaciens, Serratia marcescens, and Stenotrophomonas maltophilia. The biosensor strains Chromobacterium violaceum mutant CV026 and Agrobacterium tumefaciens A136 were used for detection of AHL signal molecules. The majority of A. hydrophila, P. aeruginosa, and S. liquefaciens strains produced more than one AHL molecule. Serratia marcescens strains were AHL positive only under detection of A136. The rest of the test species did not show any AHL production under the current detection system. These findings indicate that AHL‐ mediated quorum‐sensing systems are present in some of the ocular bacteria, and the different signal molecules may be involved with the quorum‐sensing pathway in the other bacterial species.     

Abdominal tuberculosis: CT evaluation

The computed tomography (CT) scans of 27 patients with abdominal tuberculosis were reviewed retrospectively to determine the range of abdominal involvement. Most patients had been at increased risk because of intravenous drug abuse, alcoholism, acquired immunodeficiency syndrome (AIDS), cirrhosis, or steroid therapy. The etiologic agent was Mycobacterium tuberculosis in 23 patients and M. avium-intracellulare in four patients with AIDS. In five patients, tuberculosis was limited to the abdomen. CT findings included adenopathy, splenomegaly, hepatomegaly, ascites, bowel involvement, pleural effusion, intrasplenic masses, and intrahepatic masses. Characteristic features were a tendency for adenopathy to prominently involve peripancreatic and mesenteric compartments, low-density centers within enlarged nodes, complex nature of the ascites, and adenopathy adjacent to sites of gastrointestinal tract involvement. Recognition of these manifestations and maintenance of an index of suspicion, especially in patients at risk, should help optimize the correct diagnosis and management of intraabdominal tuberculosis.     

Livedo reticularis associated with interferon α therapy in two melanoma patients

We report two patients who developed intense livedo reticularis clearly related to the administration of interferon alpha 2b as an adjuvant therapy for melanoma. Histological studies showed scattered perivascular infiltrates without vasculitis. Laboratory tests excluded any underlying condition. Resolution of the symptoms was observed in both patients when interferon alpha was withdrawn. These cases highlight the occurrence of livedo reticularis as an uncommon side-effect of interferon alpha treatment.