The hospital in Texas where two nurses became the first people to contract Ebola inside the US is mounting an aggressive public relations campaign to rescue its image, as nursing representatives call for its top executives to be held accountable for the crisis.

Texas Health Presbyterian hospital in Dallas hired Burson-Marsteller, a New York-based PR firm, to direct a fightback against sharp criticism it received after Thomas Eric Duncan, a Liberian man who was first sent home by the hospital, died there from Ebola.

It has since published slick video clips of smiling nurses praising their managers and hosted a brief “rally” of medics wielding pro-hospital placards outside the emergency room for television news cameras. Amid fears patients might stay away, the hospital has tried to flood social media with the hashtag “#PresbyProud” and issued rebuttals to allegations about its practices after nurses Nina Pham and Amber Vinson were infected while treating Duncan, who died on 8 October.

“We did everything we could within our power to treat that patient, because he was our priority,” a nurse identified as Josh said in an official video clip that was published to YouTube on Saturday afternoon. “I’m proud of my nurses and their heroic efforts”.

Three previous clips each asked Presbyterian nurses whether they felt safe at work. “I feel that I do work in a safe environment,” said Sean Faulkner. “I feel we do have the opportunity to be trained on new safety devices and new safety protocols.”

Another nurse, Thao, said she and her colleagues “know the protocols and what to do in the event of a disaster”.

Such remarks responded directly to stinging allegations made by National Nurses United, a union that said some nurses at the hospital had been moved to blow the whistle about inadequate protections of them and other patients during the treatment of Duncan.

“Were protocols breached?” asked the union, in a statement. “The nurses say there were no protocols.”

In a series of statements of its own, the hospital sharply disputed several of the allegations. One alleged that “third parties who don’t know our hospital, our employees and who were not present when the events occurred are seeking to exploit a national crisis by inserting themselves into an already challenging situation”.

Deborah Burger, co-president of National Nurses United, told the Guardian she stood by the nurses’ claims.

“If the hospital had been providing personal protection equipment, and were following the proper guidelines to protect the patients, the community and the healthcare workers, we would not have had two nurses who came down with Ebola from one facility,” she said.

Burger said nurses had told of a terrible scene in an anteroom next to the isolation room where Duncan was suffering from projectile vomiting and extreme diarrhoea, in which “every single piece of equipment the nurses wore, every piece of paper, every piece of bed linen did not go out” and accumulated because there was no adequate plan for dealing with it.

“Virus-infected stuff was piling up there,” she said. “It was a reservoir.”

Texas Health said in a statement that it went “above and beyond” national guidelines on waste.

Late on Friday afternoon, a few dozen nurses and other staff appeared to abruptly exit the hospital building to stage a brief rally outside. Some held placards, bearing slogans such as “We [heart] Presby” and “We stand with Presby”, which appeared to have been written in the same handwriting.

Nurses at Texas Health Dallas pray for patients, one another today at hospital gathering. #presbyproud pic.twitter.com/BdnED3VEBe — TexasHealthResources (@texashealth) October 18, 2014

Local TV news broadcasters were tipped off about the event. A news helicopter hovered above, capturing footage for evening bulletins, while cameras on the ground filmed from some distance away. No interviews of the participants appeared to take place, and the event ended in about half an hour.

A photograph of nurses at the gathering holding hands and praying was posted to the Twitter account of Texas Health Resources, the hospital’s operator. Calls to discuss the event with hospital spokespeople were not returned.

The hospital had by then begun to win sympathetic media coverage by publishing to YouTube on Thursday night some extraordinary video footage of Pham, which was recorded at her bedside before she was transferred to a National Institutes of Health facility in Maryland. “I love you guys,” she was shown telling her hazmat-suited doctors.

An accompanying statement that Pham was said to have “asked the hospital to release” while her condition steadily worsened, said she appreciated “everything that my co-workers have done to care for me,” and added: “I’m doing really well thanks to this team, which is the best in the world. I believe in my talented co-workers. I am #PresbyProud!”

A search on Twitter for that hashtag – reminiscent of slogans such as “Boston Strong” and “I Love Ferguson” that have proliferated in US cities suffering through no fault of their own – shows that among the few people using it are the Texas Health corporate account, Brent Boulding, a public relations executive for Texas Health, and Ted Shaw, the chief executive of the Texas Hospitals Association lobbying organisation.

“It makes it seem less of a grassroots effort among the staff and more of what sometimes is referred to as an astroturf campaign to look like grassroots,” said Mark Graban, a Texas-based healthcare consultant. “People should be supportive of the nurses and individuals who performed heroically, but the hospital itself failed.”

Texas Health has indeed conceded that it made errors. The line its staff are required to take appears to be that bosses acknowledge that they “made mistakes” and are “deeply sorry”. Those phrases were used both by Dr Daniel Varga, the chief clinical officer, in his written testimony to the US Congress on Thursday afternoon, and in a statement issued by the hospital operator that evening.

Yet notably absent from public view during this period of intense, international attention have been the hospital’s three most senior executives, including its acting president, Jim Berg, who rose to the position only in August this year, when his predecessor, Britt Berrett, who was paid more than $1.2m a year, left after four years to teach at the University of Texas in Dallas.

Equally shielded from public scrutiny has been Cole Edmonson, who as Dallas Presbyterian’s chief nursing officer is the senior manager to both Pham and Vinson. Edmonson, who according to the hospital’s latest tax filing is paid more than $410,000 a year, owns three homes and a boat in Texas, according to public records. In 2012 he delivered a TED talk while wearing a full flight suit, in which he offered his vision for the future of nursing, including the need to “deconstruct the hierarchies of care”.

Nursing leaders called for Edmonson, who did not respond to a request for an interview, to take responsibility for the fact that two of his nurses had contracted the deadly virus while at work.

“As far as the nurses are concerned, there has been no leadership on this issue other than blaming the nurse and blaming the patient,” said Burger. “He is collecting a paycheck for making sure that his employees are safe. He should be held accountable.”