2015 July – Rosslea (Queensland) – E.coli

Rosslea (Queensland): E.coli
Incident Description: Detection of E.coli (1 org/100ml) in Rosslea house sample on 8th July 2015. Sample had a chlorine concentration of 1.3mg/L Free Chlorine and 1.7mg/L Total Chlorine. The
E.coli rolling percentage average for the month was 99.9%
Corrective and Preventative Actions: The sample point was inspected and it was discovered that the sample address (house sample point) had become derelict and had no turnover of water (2KL consumed in the preceding year). It was ascertained that the sample was compromised by the poor sample location. A dedicated sample point was installed in a park nearby. Resamples and all further samples have come back clear of E.coli. It must be noted that this non-compliance led to an overhaul of all of Townsville City Council’s sampling locations.

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011