Case Proves Global Nature of Infection Control

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Apparently brought in by a hospital patient from the Punjab region of India, a persistent strain of methicillin-resistant Staphylococcus aureus (MRSA) has become endemic in a Vancouver hospital and has established a troublesome foothold in another facility in Winnipeg, Canadian clinicians tell Hospital Infection Control.

The Centers for Disease Control and Prevention in Atlanta has increasingly emphasized the global nature of infection control in recent years, including the analogy that exotic pathogens are only a plane ride away. The Canadian MRSA outbreak may prove an apt case in point, as approximately 110 additional cases have been linked to the index case in the Vancouver area alone, says Moira Walker, RN, CIC, senior infection control nurse at Vancouver Hospital and Health Sciences Center. As a result of the outbreak, strict protocols for MRSA infection control have been developed at our hospital. (included at end of article)

“Our rate has declined, but we now have this pool of MRSA-positive patients out in the community with this highly epidemic strain,” she says. It’s still going on, and it’s been going on since the first week of April in 1993.”

It was at that time that a patient in his late 70’s returned to Vancouver from a visit to his native India, where he also had been under hospital care at Dayanand Hospital in the Punjab. Shortly upon returning to Canada, he was hospitalized with skin lesions, congestive heart failure, and chronic renal failure, Walker says.

“He grew MRSA from all sites, and anyone with a decimating skin condition has the potential to spread it more rapidly,” she says.

Initial transmission may have occurred rapidly because the patient was admitted over a long holiday weekend, MRSA infection was not yet determined, and he was not placed immediately under contact isolation. Instead, the patient was admitted to a regular four-bed medical unit, but promptly isolated after the MRSA was discovered.

“The anterior nares were swabbed on the other patients in the room, and we found indeed that the 3 others had become colonized,” Walker says. “Then the whole ward was swabbed, and we found several other MRSA patients.”

To complicate control efforts, a patient originally on the same ward as the index case was discharged and later readmitted to a surgical ward in the same hospital. The same strain of MRSA was

cultured from a draining wound, but by that time, 12 other patients in the surgical ward had acquired MRSA, she adds.

Environmental cultures explained in part why so much transmission was occurring – the MRSA strain called Type 25 was proving remarkably persistent in the environment and impervious to routine cleaning measures. In one case, a newly admitted patient acquired MRSA after being placed in the same bed used by an MRSA patient 5 weeks earlier, she says.

“That demonstrates the fact that it must have been persisting in the environment – it is a pretty hardy survivor,” Walker says.

Even after terminal cleaning with a 2% solution of phenolic germicide, 18 of 21 cultures taken around the room of a discharged MRSA patient were positive, Walker says. Fortunately, the MRSA was eradicated from environmental surfaces after a more rigorous and methodical cleaning protocol was adopted that involved using throw-away wipes dipped directly into the phenolic solution. Wipes were discarded for a fresh one after only a short use, for example, wiping down a bed rail.

“It’s very persistent, but fortunately it is not highly pathogenic,” she says. “It’s not causing a lot of disease, but it is sure a big nuisance. In some patients, we have found that it cleared and seemed to stay cleared. There are some patients that have not cleared and keep coming back.”

To make a difficult situation worse, a patient discharged from the Vancouver hospital – who was not known to be colonized with MRSA – was transferred to the Health Sciences Centre in Winnipeg, and the strain subsequently spread to 15 patients and one staff member. The initial outbreak was brought under control, but six months later, cases began to reappear, says Susan Roman, MD, a fellow in medical microbiology at the hospital.

“We just found two more today,” she says. “We are up to 28 patients now. We thought we had it under control, but new patients seem to be surfacing now.”

Patients are being placed under strict isolation measures, and clinicians have devised an antibiotic protocol that is proving successful at MRSA decolonization. No like strains have been found in the community, but clinicians are beginning to screen groups of patients more aggressively where previous cases have occurred, for example, in a dialysis unit and on a chest service ward.

“We decided to screen the whole ward – we’ve become more aggressive in looking for other cases,” she says. “Before, we were hesitant because it’s very expensive and a lot of work. But

now we feel we have to in order to find the cases that seem to be lurking out there. We want to find them before they’ve had a chance to spread it to other patients.”

An underlying incentive to preventing the MRSA strain from establishing an endemic presence is that it will increase the temptation to add an effective drug to empiric regimens – vancomycin.

“We are already controlling our vancomycin use to prevent the emergence of vancomycin-resistant enterococci, so that would not be good,”Roman notes.

The same strain of MRSA also has been found at Mission (British Columbia) Memorial Hospital, suggesting the possibility of rapid global and national spread of single pathogen. Similar importation of drug-resistant pathogens from Asia and Europe is likely to continue, suggesting that hospitals today are operating increasingly in a global village rather than isolated regions.

“You have to be more careful now about patients and their travel history – not just with respect to unusual infectious diseases,” Roman says. “With any hospitalization they may have had, they could have acquired ordinary bugs with very resistant antimicrobial profiles, which is just as important from a hospital epidemiology view.”

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