Expert witness’s evidence on antibiotics highly significant

Yesterday the first expert medical witness called by coroner Dr Ciarán MacLoughlin provided the Savita Halappanavar inquest with some highly significant evidence.

A consultant microbiologist at the National Maternity Hospital in Dublin, Dr Susan Knowles is one of the Republic’s foremost experts on infections which affect pregnant women and newborn babies.

Dr Knowles commented on the choice of antibiotics used as part of Ms Halappanavar’s treatment (see panel). She said: “The aspect I have concern with is the choice of intravenous antibiotics.”

Her concern specifically related to the use of co-amoxiclav, because many strains of E.coli – the bug that caused the septicaemia that killed Ms Halappanavar – are increasingly resistant to this antibiotic.

In a case such as this, she said, many centres in Ireland would add an additional antibiotic, for example gentamicin, to the co-amoxiclav, or may decide to use an entirely different, broader spectrum, antibiotic.

It also emerged that all three Dublin maternity hospitals include the drug gentamicin in their protocols for the treatment of chorioamnionitis. Gentamicin is a broad-spectrum antibiotic used in the treatment of bugs such as E.coli.

Anaerobes
Dr Knowles had no criticism of the use of metronidazole, an antibiotic effective against a different group of microbes called anaerobes. Although Ms Halappanavar was not infected by an anaerobic organism, they are a common cause of pregnancy-related sepsis, and so the drug was necessary to cover this eventuality pending the exact identification of the bacterium.

At lunchtime on Wednesday October 24th, consultant obstetrician Dr Katherine Astbury sought the advice of consultant microbiologist Dr Deirbhile Keady, who recommended changing the treatment to gentamicin and piperacillin/ tazobactam. It subsequently emerged that the E.coli bacterium with which she was infected was sensitive to both these drugs but to neither co-amoxiclav nor metronidazole.

On October 25th, preliminary indications, subsequently disproved, suggested the E.coli was resistant to piperacillin/ tazobactam. As a result this antibiotic was stopped and meropenem given in its place. The microbe was subsequently found to be sensitive to this antibiotic. Dr Knowles concluded the antibiotic treatment given to Ms Halappanavar from 6am to lunchtime on Wednesday 24th did not follow University Hospital Galway sepsis in obstetrics management guidelines.

Meanwhile, the expert witness was critical of some clinical aspects of Ms Halappanavar’s early management, including the failure to follow up on the initial blood test taken from the patient. She said if samples are taken “it is important they are followed up”.

Nor was she impressed with the failure to record comprehensively the deceased’s vital signs prior to her transfer to the high dependency unit. After the ward round on the morning of October 24th there was a delay in recognising that the patient was deteriorating further, she said. She added that medical staff should have been called earlier when the systolic blood pressure was dropping.

Dr Knowles’s expert report provided great clarity and was a model of its type.