The BBC reports that experts are warning that bugs such as MRSA have been spreading in the wider community environment. They want doctors to be alert to the most dangerous form of MRSA that can attack the lungs and may strike young people in particular.
Panton Valentine leukocidin (PVL) strains of community-acquired MRSA can cause a condition called necrotizing pneumonia, which destroys lung tissue.
This only affects a minority of those infected, but can be deadly.
"These new strains of bacteria appear to be able to stick to damaged skin and airways better than the hospital MRSA strains, and they can also multiply at a faster rate," says Dr Marina Morgan, of the Royal Devon and Exeter Foundation NHS Trust.
So far these strains are mainly spreading in the US, where 12% of all MRSA cases are community-acquired, but the UK has seen an increasing number of cases.
It is unclear why children seem to be at particular risk, but the speculation is that older people in the community have fewer cuts and abrasions - a key transmission route - and have less contact with other people.
Nursing home threat
Meanwhile, Irish researchers are examining a new breed of bacteria which carry enzymes called extended spectrum beta lactamases (ESBLs), which are capable of destroying a many common antibiotics.
They include a strain of E. Coli, which is spreading into nursing homes and communities across Europe.
This was held responsible for a severe outbreak of cystitis, a bladder infection, in the UK between 2003 and 2004.
"Although cystitis is not life threatening, it is the most common form of urinary tract infection, and the economic consequences of failing to treat an outbreak quickly and properly are considerable," said Dr Dearbhaile Morris, of the National University of Ireland.
"In severe infections, patients may suffer serious complications if the first antibiotic given to them does not work."
Mark Enright, professor of molecular epidemiology at Imperial College, said he was "not surprised" by the findings.
"The emergence and spread of ESBL E. Coli does give physicians problems in providing proper initial care for some patients especially those with urinary tract infections."
He added: "The control of infections in many nursing homes is inferior to hospitals despite the medication and specialist care required by some residents."