Resistance Patterns of Frequently Applied Antimicrobials and Occurrence of Antibiotic Resistance Genes in Edwardsiella tarda Detected in Edwardsiellosis-Infected Tilapia Species of Fish Farms of Punjab in Pakistan.

Edwardsiella tarda is one of the most significant fish pathogens, causes edwardsiellosis in a variety of freshwater fish species, and its antibiotic resistance against multiple drugs has made it a health risk worldwide. In this study, we aimed to investigate the antibiotic resistance (ABR) genes of E. tarda and establish its antibiotic susceptibility. Thus, 540 fish (299 Oreochromis niloticus, 138 O.mossambicus, and 103 O. aureus) were collected randomly from twelve fish farms in three districts of Punjab in Pakistan. E. tarda was recovered from 147 fish showing symptoms of exophthalmia, hemorrhages, skin depigmentation, ascites, and bacteria-filled nodules in enlarged liver and kidney. Antimicrobial susceptibility testing proved chloramphenicol, ciprofloxacin, and streptomycin effective, but amoxicillin, erythromycin, and flumequine ineffective in controlling edwardsiellosis. Maximum occurrence of qnrA, blaTEM, and sul3 genes of E. tarda was detected in 45% in the liver, 58%, and 42% respectively in the intestine; 46.5%, 67.2%, and 55.9% respectively in O. niloticus; 24%, 36%, and 23% respectively in summer with respect to fish organs, species, and season, respectively. Motility, H2S, indole, methyl red, and glucose tests gave positive results. Overall, E. tarda infected 27.2% of fish, which ultimately caused 7.69% mortality. The Chi-squared test of independence showed a significant difference in the occurrence of ABR genes of E. tarda with respect to sampling sites. In conclusion, the misuse of antibacterial agents has led to the emergence of ABR genes in E. tarda, which in association with high temperatures cause multiple abnormalities in infected fish and ultimately resulting in massive mortality.

Crescentic glomerulonephritis associated with bacterial endocarditis--antibiotics alone may be sufficient. A case report.

Crescentic glomerulonephritis complicating the course of bacterial endocarditis carries a poor prognosis. Ideal treatment strategy is not clearly defined. In addition to antibiotic treatment, plasmapheresis and steroids have been used with variable results. Here we report a case of 40-year old female who was referred because of generalized body swelling and decrease urine output associated with low grade fever on and off for two to three months. She was diagnosed to have acute renal failure secondary to tricuspid valve endocarditis. Staph aureus was isolated from blood culture and renal biopsy showed crescentic glomerulonephritis. She received dialysis support and antibiotics and had complete recovery of renal function 6 weeks after initiation of therapy. Eradication of infection with antibiotics treatment may be sufficient for resolution of crescentic glomerulonephritis associated with infective endocarditis in some cases.