Bacteriological and histopathological findings in cetaceans that stranded in the Philippines from 2017 to 2018

Abstract

The relatively high frequency of marine mammal stranding events in the Philippines provide many research opportunities. A select set of stranders (n = 21) from 2017 to 2018 were sampled for bacteriology and histopathology. Pertinent tissues and bacteria were collected from individuals representing eight cetacean species (i.e. Feresa attenuata, Kogia breviceps, Globicephala macrorhynchus, Grampus griseus, Lagenodelphis hosei, Peponocephala electra, Stenella attenuata and Stenella longirostris) and were subjected to histopathological examination and antibiotic resistance screening, respectively. The antibiotic resistance profiles of 24 bacteria (belonging to genera Escherichia, Enterobacter, Klebsiella, Proteus, and Shigella) that were isolated from four cetaceans were determined using 18 antibiotics. All 24 isolates were resistant to at least one antibiotic class, and 79.17% were classified as multiple antibiotic resistant (MAR). The MAR index values of isolates ranged from 0.06 to 0.39 with all the isolates resistant to erythromycin (100%; n = 24) and susceptible to imipenem, doripenem, ciprofloxacin, chloramphenicol, and gentamicin (100%; n = 24). The resistance profiles of these bacteria show the extent of antimicrobial resistance in the marine environment, and may inform medical management decisions during rehabilitation of stranded cetaceans. Due to inadequate gross descriptions and limited data gathered by the responders during the stranding events, the significance of histopathological lesions in association with disease diagnosis in each cetacean stranding or mortality remained inconclusive; however, these histopathological findings may be indicative or contributory to the resulting debility and stress during their strandings. The findings of the study demonstrate the challenges faced by cetacean species in the wild, such as but not limited to, biological pollution through land-sea movement of effluents, fisheries interactions, and anthropogenic activities.

Fecal and skin microbiota of two rescued Mediterranean monk seal pups during rehabilitation

“…In the first period, the fecal microbiota was dominated by the Shigella , Streptococcus , Enterococcus , Lactobacillus, and Escherichia genera. Shigella and Escherichia have been found to co-occur in the feces of captive belugas and Pacific white-sided dolphins ( 42 ), dwarf sperm whale ( Kogia breviceps ) ( 43 ), and harbor seals ( 44 ). However, it is often considered as a disease-causative agent for humans and other primates, but it remains unclear if it is pathogenic to other mammals, including marine ones.…”

Case report: Fatal neonatal sepsis associated with Escherichia fergusonii infection in a common bottlenose dolphin (Tursiops truncatus)

“…Especially, in veterinary medicine, E. fergusonii has been reported to cause enteritis, and septicemia in horse and goat, fibrinonecrotic typhlitis in fowl, and fibrinous bronchopneumonia in cattle ( 18 ). Although a case report reported isolation of E. fergusonii in lungs of Globicephala macrorhynchus ( 19 ), its pathology and clinical importance have rarely been reported in aquatic organisms; therefore, it is not considered as the primary causative agent of sepsis in aquatic organisms, including dolphins. Prompt diagnosis and adequate clinical treatment are pivotal for the prognosis of sepsis in neonates.…”

“…Prompt diagnosis and adequate clinical treatment are pivotal for the prognosis of sepsis in neonates. Antimicrobial resistance (AMR) was reported in E. fergusonii ( 19 – 21 ). Previous studies reported its wide-ranging resistance against nitrofurantoin, ciprofloxacin, ceftriaxone, amikacin, oxytetracycline, tetracycline, amoxicillin, amoxicillin-clavulanic acid, ampicillin, cefoxitin, penicillin, nalidixic acid, quinolone, and erythromycin ( 20 , 21 ).…”

“…Therefore, these antibiotics are not best option for the treatment of E. fergusonii . AMR against erythromycin for treatment of Escherichia species was reported in cetaceans ( 19 ). AMR against cephalothin, ampicillin, cefazolin were also observed in the bacteria isolated from cetaceans which might be ruled out for the treatment ( 19 ).…”

“…AMR against erythromycin for treatment of Escherichia species was reported in cetaceans ( 19 ). AMR against cephalothin, ampicillin, cefazolin were also observed in the bacteria isolated from cetaceans which might be ruled out for the treatment ( 19 ). In contrast, E. fergusonii are reported to be susceptible to florfenicol, gentamicin, and trimethoprim-sulfamethoxazole.…”