No signs of infection were detected in a baby girl whose case is central to claims made by Lucy Letby’s defense, asserting the infant was exposed to a dangerous bacterium in the hospital, the Daily Mail has uncovered.

Letby’s new legal representatives argue that the waterborne bacterium, stenotrophomonas maltophilia, was identified in the breathing apparatus of Baby I. Letby was found guilty of murdering the infant in October 2015.

This bacterium has also been implicated in the deaths of six individuals at a Glasgow hospital. Letby’s lawyers believe this connection could be pivotal in proving her innocence.

The defense suggests that sewage leaks in the neo-natal unit at the Countess of Chester Hospital could have been a breeding ground for the bacterium, potentially contributing to the deaths of several babies.

Despite these claims, no evidence during Letby’s trial indicated that any of the victims suffered from bacterial or parasitic infections related to contaminated water. Documents reviewed by the Mail reveal that although the bacterium was detected in Baby I’s breathing tube in September 2015, it had not developed into an infection by the time of her death on October 23.

Stenotrophomonas maltophilia, also known as pseudomonas maltophilia, is a common bacterium found in soil and plants. It rarely causes problems for healthy individuals but is capable of causing pneumonia in vulnerable patients, such as premature babies or people suffering from cancer and other conditions that compromise immunity.

Crucially, Baby I’s post-mortem examination showed no evidence of pneumonia or any other inflammatory infection which would be expected if she had such a bacterial infection at the time of death.

According to the post-mortem report: ‘(There was evidence of) early stage chronic lung disease (due to immaturity and prolonged ventilation) without inflammation or recent bleeding.’

Lucy Letby is serving 15 whole life sentences for the murder of seven babies and attempted murder of seven more at the Countess of Chester Hospital, between June 2015 and June 2016

Defence expert Dr Mike Hall found Baby I was ‘colonised with but not infected by’ the hospital bug

A photograph of the sympathy card that Letby sent to the parents of Baby I, which was shown to the jury at her 10-month trial at Manchester Crown Court

In the card Letby apologised for not being able to attend Baby I’s funeral. She murdered the tot by injecting her with air

Also significantly, Dr Mike Hall, the defence expert neonatologist, who was never called to give evidence in Letby’s trial, also ruled out the bug as being important.

In his report on Baby I, also seen by the Mail, he says she was ‘found to be colonised with (but not infected by) a bacterium called stenotrophomonas maltophilia.’

In other words, the bacterium was not to blame for Baby I’s death, according to the expert.

Letby’s trial, at Manchester Crown Court, also heard there was no evidence of pneumonia on an X-ray, taken around 40 minutes before she collapsed. There was, however, a large bubble of air in her stomach, the jury was told.

Letby was convicted of attacking Baby I three times over the course of three weeks, before murdering her on the fourth attempt, by injecting air into her stomach and bloodstream.

The 36-year-old is currently serving a record 15 whole life terms after being convicted of murdering seven babies and attempting to murder seven more – one of whom she attacked twice – at the Countess of Chester Hospital, between June 2015 and June 2016.

The court heard Baby I had been born 13 weeks early at the end of August 2015, weighing just 2lbs 2oz. 

Despite being very premature she was ‘gaining weight nicely’ and her death, at almost three months old, shocked nurses on the neo-natal unit.

Mark McDonald is representing Letby and claims she is the victim of a miscarriage of justice

An artist’s drawing of Lucy Letby giving evidence at Manchester Crown Court

Letby worked as a nurse on the neonatal unit at the Countess of Chester Hospital

Afterwards, Letby wrote a gushing sympathy card to Baby I’s parents, saying she was ‘sorry’ she couldn’t attend her funeral with colleagues to ‘say goodbye.’

‘There are no words to make this time any easier,’ she wrote.

‘It was a real privilege to care for Baby I and get to know you as a family. 

‘A family who always put Baby I first and did everything possible for her. She will always be part of your lives and we will never forget her. Thinking of you always, sorry I cannot be there to say goodbye.’

A picture of the card – taken around 7.30am on the morning of Baby I’s funeral, when Letby was finishing a nightshift at the hospital – was found on her mobile phone when she was arrested by police almost three years later.

Letby denied getting a ‘thrill’ out of the picture, but admitted it was the only time she had sent a condolence card to parents of a deceased baby and it was not a ‘normal’ thing to do.

The prosecution said she had kept it as a ‘trophy’ of Baby I’s murder.

The court also heard that Letby, who was on duty but not assigned to care for Baby I on the night she died, was found with her ‘hands inside’ the tot’s incubator when she collapsed.

Nurse Ashleigh Hudson gave evidence that she was alerted that Baby I was in distress by a ‘loud, relentless’ cry, which was ‘markedly very different to how she had cried before when she was hungry.’

She said she saw Letby with her hands inside Baby I’s incubator, apparently trying to settle her with a dummy. 

The prosecution said Letby had injected Baby I with air, causing her to cry out in pain, moments earlier.

Nurse Hudson also told the jury about another alleged attack which happened 10 days earlier, while she had nipped away from Baby I’s cot momentarily to help a colleague.

When she returned, Letby appeared in the doorway of the nursery and – although the lights were off and there was a canopy over the cot covering Baby I’s face – told Ms Hudson the infant ‘looked pale.’

Ms Hudson went to check on the tot and found her ‘incredibly pale’, ‘floppy’ and ‘gasping’ for breath. Doctors only just managed to save her after 20 minutes of CPR.

Letby was questioned by prosecutor Nick Johnson KC about how she could possibly have seen from the doorway that the baby was ‘pale’ when the lights were off.

She replied: ‘I knew what I was looking for,’ then quickly corrected herself, adding: ‘at.’

Letby then immediately appeared agitated and flustered, before asking to take a break in her cross-examination.

The mother of Baby I also gave evidence about Letby’s ‘strange’ behaviour after her daughter’s death, which she described as making her feel ‘uncomfortable.’

She told the public inquiry into the baby deaths at the Countess of Chester Hospital that she was ‘shocked’ to see Letby’s name all over her daughter’s medical notes because she had had little to do with her, compared to other nurses.

The mother said she thought Letby was ‘quiet and a bit odd.’

‘She always seemed a bit of a loner,’ the woman, who can’t be named for legal reasons, said. ‘I remember thinking she seemed miserable compared to the others and I never saw her interact with parents much.’

Letby was also ‘smiling weirdly’ after Baby I died, the mother said.

‘She (Letby) was smiling and kept going on about how she was present at our baby’s first bath and how much our baby had loved it,’ the mother told the Thirlwall Inquiry. 

‘I remember thinking at the time, ‘’What are you going on about, she’s only ever had one bath and my husband never got to bath her’’.

‘I just felt so sorry for him because he hasn’t got that memory and I wished Lucy would just stop talking. I remember thinking, ‘’Will you just go away’’.

‘I was really uncomfortable and I just wanted her to leave. It was also weird that she kept smiling. Eventually, I think she realised and stopped.

‘It wasn’t something we wanted to hear right then so I put it down to saying the wrong thing at the wrong time. However, I still thought her behaviour was strange.

‘I mentioned it to my mum who said that maybe Lucy was trying to put a nice mood on it, but there was no nice mood.’

Letby, formerly of Hereford, is currently a prisoner at HMP Bronzefield, in Surrey. She has twice tried and failed to appeal against her convictions.

Mr McDonald has submitted reports from 26 medical experts to the Criminal Cases Review Commission, the body that investigates potential miscarriages of justice, in a bid to have her case reviewed and heard for a third time at the Court of Appeal.

The barrister claims his new expert panel are impartial, although the Mail previously revealed that they were recruited by Canadian neonatologist Dr Shoo Lee, whose evidence for the defence was dismissed by the Court of Appeal, and who wrote to fellow medics, saying: ‘We might be her (Letby’s) last hope.’

Another panel member, Professor Neena Modi, was also head of the Royal College of Paediatrics and Child Health (RCPCH) in 2016 when it carried out a flawed review into the neo-natal unit at the Countess.

A redacted version of their report – which omitted references to Letby and instead flagged up staffing shortages, problems with the transfer of babies to other hospitals and other issues as potential causes for the spike in baby deaths – was used by hospital managers to exonerate Letby, discredit doctors, mislead parents and delay the police probe.

A new Netflix documentary on Letby’s case, which shows her being arrested by police in bed, is being released on Wednesday February 4.