A cross-sectional survey of snake oral bacterial flora from Hong Kong, SAR, China.

OBJECTIVE: To determine the pattern of oral bacterial flora and their sensitivity to antibiotics in freshly captured native snakes in Hong Kong SAR, People's Republic of China. METHODS: Healthy native snakes were captured and kept in a designated centre. Snake species were identified by experienced herpetologists. Mouth swabs were taken by the veterinarian using strict aseptic techniques. The snakes were released back to the wild immediately after the above procedure. Swabs were sent for microbiological studies of bacterial culture and antibiotic sensitivity. RESULTS: 47 venomous snakes of the families Colubridae, Elapidae and Viperidae and 53 non-medically important snakes were captured. 406 bacterial isolates of 72 different species were cultured: these included gram negative and positive bacterial species and also anaerobic bacterial species. With the exception of the white-lipped pit viper (Cryptelytrops albolabris), venomous snakes harboured more pathogenic bacteria and total bacteria species compared to the non-medically important species. Of the venomous snakes, the Chinese cobra (Naja atra) harboured the largest number of bacterial species. In the present study, all gram negative bacteria associated with wound infection were sensitive to levofloxacin, netilmicin and piperacillin/tazobactam. Many gram negative bacteria in the study were not sensitive to cefuroxime axetil. Amoxicillin/clavulanic acid was an appropriate choice to cover Enterococcus faecalis and anaerobes. CONCLUSION: In the presence of wound infection from snakebite injury in Hong Kong, first line empirical antibiotics include amoxicillin/clavulanic acid plus levofloxacin. Prophylactic antibiotics may be considered in selected cases of Chinese cobra (N. atra) bite, otherwise prophylactic antibiotics are not recommended in snakebite unless tissue necrosis is present.

Local antivenom treatment for ophthalmic injuries caused by a Naja atra.

We report a case of local antivenom therapy for ocular exposure to the venom of Naja atra. An 83-year-old woman sustained conjunctival and corneal injuries by the venom of a spitting N. atra. Local instillation of N. naja antivenom quickly relieved the pain as measured by visual analog scale, and she recovered uneventfully. Good recovery ensuing topical antivenom administration for ocular exposure to the venom of spitting N. atra and Naja nigricollis has been described in literature, but the pain response was not thoroughly documented. The mechanism of antivenom for pain relief remains to be established. In light of the associated positive outcome observed in human, the role of ocular antivenom therapy merits further study.

Hemolytic anemia after zopiclone overdose.

INTRODUCTION: Zopiclone is associated with methemoglobinemia. We report a case of zopiclone overdose manifested with another hematological complication, hemolysis. CASE: A 46-year-old woman overdosed with 50-100 tablets of 7.5 mg zopiclone. Oxidative hemolysis was evident by anemia, bite cells, raised unconjugated bilirubin and lactate dehydrogenase, lowered haptoglobin, and reticulocytosis. DISCUSSION: In zopiclone overdose, there may be oxidative stress rendering the development of not only methemoglobinemia but also hemolysis.

Two cases of methemoglobinemia following zopiclone ingestion.

INTRODUCTION: Most cases of methemoglobinemia result from exposure to certain medications and chemicals such as nitrates, nitrites, aniline, dapsone, phenazopyridine, benzocaine, and chlorates which oxidize the iron from the ferrous state. Intoxication with zopiclone is expected to produce drowsiness, confusion and coma but not methemoglobinemia. We report two cases of zopiclone overdose with methemoglobinemia. CASE REPORTS: Case one: A 43-year-old woman presented to the emergency department two hours after ingesting 100 tablets of 7.5 mg zopiclone. Her initial vital signs, physical examination, chest x-ray, and electrocardiogram were normal. Two hours post-ingestion her methemoglobin level was 9.8%; 14 hours post-arrival she showed cyanosis of the lips and extremities and dyspnea after walking. The blood sample 16 hours post-ingestion was dark brown in color and the methemoglobin was 23.8%. Shortly after the second of two doses of methylene blue (1 mg/kg each) her methemoglobin was 3.6%. Case two: A 30-year-old woman came to the emergency department 50 hours after ingesting 150 to 200 tablets of 7.5 mg zopiclone. Her vital signs and physical examination were normal. Her methemoglobin level was 5.2% at 52 hours post-ingestion and it peaked at 10.4% one hour later. She recovered following symptomatic care. DISCUSSION AND CONCLUSIONS: Methemoglobinemia has not previously been reported following acute zopiclone overdose. In our patients, there were no identifiable alternative causes explaining the methemoglobinemia and zopiclone was confirmed in both patients by laboratory analysis. These two cases suggest that zopiclone overdose is capable of producing delayed methemoglobinemia, which may be related to formation of a sufficient quantity of the N-oxide metabolite.