A simultaneous outbreak on a neonatal unit of two strains of multiply antibiotic resistant Klebsiella pneumoniae controllable only by ward closure

Two aminoglycoside-resistant strains of Klebsiella pneumoniae caused an out break on the neonatal unit at St Thomas' Hospital. One, which affected 18 p atients, was capsular type K18 and resistant to ne,,ver cephalosporins by t he production of the extended-spectrum beta -lactamase SHV-2; the other, wh ich colonized four patients, was capsular non-typeable and did not produce extended-spectrum beta -lactamase. Both strains were probably brought into the unit by carrier patients; the probable carrier of the nontypeable strai n was transferred from another hospital but was negative on a single admiss ion screen; the probable carrier of the K18 strain was not screened on admi ssion because he had been born at St Thomas', but his mother had been trans ferred from another hospital. Despite intensive efforts to control the outb reak by standard methods of hand washing, screening, patient isolation and environmental cleaning, a total of 22 neonates on the unit eventually becam e colonized or infected. One of three patients with bacteraemia died. A sma ll proportion of samples of expressed breast milk, electronic thermometers and oxygen saturation probes were contaminated by the K18 strain and may ha ve contributed to some of the cross-infection, but this did not explain the extent of the outbreak. The outbreak was controlled only by opening a temp orary ward for colonized neonates and another for newly born babies, which allowed the closure and cleaning of the main neonatal unit. Multiply antibi otic resistant klebsiellas may be highly epidemic and cause serious, diffic ult-to-control outbreaks on neonatal units. All patients, regardless of the ir admission history, should be screened on admission for carriage of multi ply resistant enterobacteria by a sensitive method, and units should have p lans for temporary ward closure should outbreaks occur. (C) 2001 The Hospit al Infection Society.