Spread of Klebsiella in a neonatal ward

Nosocomial outbreak of gentamicin-resistant Klebsiella pneumoniae in a neonatal intensive care unit controlled by a change in antibiotic policy

Between August and November 1997, a nosocomial outbreak caused by gentamicin-resistant Klebsiella pneumoniae occurred in the Neonatal Intensive Care Unit (NICU) of our hospital. Thirteen neonates became colonized and three of them became infected. Comparison of the isolates by amplified fragment length polymorphism (AFLP) revealed clonal similarity for isolates of eight neonates (homology > 90%). Cultures from environmental specimens were negative for gentamicin-resistant K. pneumoniae. A case-control study was conducted to identify risk factors associated with acquisition of gentamicin-resistant K. pneumoniae. Risk factors were low gestational age and birth weight. These neonates need more care and handling and may therefore, be more at risk of colonization. Length of stay on the NICU was significantly longer for cases, but mean time until colonization (6.3 days) was shorter than the total stay for controls (9.5 days). No single member of the medical or nursing staff was significantly more involved with cases than with controls. The outbreak was stopped by replacing gentamicin by amikacin as the antibiotic of first choice whenever the use of an aminoglycoside antibiotic was indicated.

Neonatal airway colonization with gram-negative bacilli: association with severity of bronchopulmonary dysplasia

BACKGROUND

Airway colonization with Gram-negative bacilli (GNB) and Gram-positive cocci (GPC) is common in mechanically ventilated neonates. Whether GNB are related to nosocomial bloodstream infection (BSI) and/or to the severity of bronchopulmonary dysplasia (BPD) is unknown.

METHODS

We prospectively examine this relationship using a cohort design. Data from 260 < or = 1250-g birth weight inborn infants (1991 to 1995) intubated > or = 2 weeks included 917 serial tracheal cultures and 583 blood cultures. The severity of BPD was assessed by duration of mechanical ventilation, oxygen dependency at 36 weeks of postconceptional age and the use of home oxygen supplementation.

RESULTS

After 2 weeks of ventilation, 80% of the infants were colonized with GPC (Staphylococus epidermidis and Staphylococcus haemolyticus in 90% of the cases). Superimposed on 36% of these infants was GNB airway colonization with Klebsiella pneumoniae (25%), Enterobacter cloacae (25%), Escherichia coli (25%), Pseudomonas aeruginosa (10%), Serratia marcescen (10%), Acinetobacter baumannii and Haemophilus influenzae (5%). Comparison between 174 GPC- and 86 GNB-colonized infants showed that demographics, birth weight, gestational age, perinatal risk factors and mortality were similar. Fifteen percent of GNB-colonized infants developed BSI caused by GNB and 14% developed BSI caused by GPC. No significant temporal relationship between airway colonization and BSI was noted. GNB infants were ventilated longer and required oxygen at 36 weeks of postconceptional age and home oxygen supplementation twice as often as infants colonized only with GPC. GNB colonization was a predictor of severe BPD after controlling for ventilation. Ureaplasma colonization occurred in 28% of GNB-colonized and 33% of noncolonized infants and was not a predictor of BPD severity.

CONCLUSION

GNB airway colonization creates a moderate risk for BSI. Antibiotic treatment does not regularly eradicate GNB. GNB airway colonization is associated with severe BPD, but further studies will be necessary before therapeutic efforts to eradicate GNB from the airways should be undertaken.

Establishing an infection control structure

In studies from the USA it has been shown that infection control can lower infection rates by 30%. To achieve this an infection control programme has to be given a firm structure. Judging from the opinions presented by an educational workshop within the International Federation of Infection Control (IFIC) and from the literature there is an international consensus on the basic components of hospital infection control. An infection control team, with the task of identifying areas of concern, providing or initiating work on written policies, educating and advising not only medical staff but also hospital administrators, constructors etc., constitutes the backbone of infection control. However, in most countries the infection control team, should it exist, is usually understaffed. This is false economy, a qualified medical input is a proven investment.

Antibiotic-resistant gram-negative bacteria in the critical care setting

Gram-negative bacilli that are resistant to commonly used antibiotics are a growing problem in seriously ill, hospitalized patients. Numerous outbreaks involving these organisms have been reported in intensive care nurseries and among critically ill adults. In endemic situations, the major reservoir for these pathogens is the patient; occasionally, transmission from patient to patient occurs through the hands of caregivers. Although the degree of antibiotic use probably plays some role in the emergence of antibiotic-resistant gram-negative bacilli, this relationship has not been uniformly demonstrated, and other factors intrinsic to the organisms themselves and to the critically ill patient may play an important role.

An outbreak of multiresistant Klebsiella in a neonatal intensive care unit

An outbreak of multiresistant Klebsiella pneumoniae occurring in a neonatal intensive care unit is described. All infections developed at least 5 days after admission to the unit (range, 5-40 days). Four infants had septicaemia and one had urinary tract infection. Three of the infected infants died. All klebsiella isolates were resistant to ampicillin, cefotaxime, cefuroxime, co-amoxiclav, mezlocillin, chloramphenicol, gentamicin, and ceftazidime (except in two); all were susceptible to imipenem, amikacin and quinolones. An extensive case-control study identified the following significant risk factors for colonization: prematurity; presence of indwelling catheters; previous antibiotic treatment; and parenteral nutrition. The outbreak was controlled with re-emphasis on strict handwashing practices, cohorting, closure of the unit to outborn admissions, and changing the regimen of empirical antibiotic therapy. Physicians should be aware of multiresistant Klebsiella spp. and change treatment whenever clinically indicated, even before culture results are available.