Letters
169
to the Editor
Sir,
Outbreak
of chest infections
with
Serratia
marcescens
We report an iatrogenic outbreak of chest infection with Serratia marcescens in an acute medical ward housing mostly patients with respiratory disorders. Ten patients out of a total of 23 in the ward were affected, within a span of 2 weeks, most of them suffered primarily from chronic obstructive airways diseases (COAD). As far as we know, a common source outbreak of S. marcescens, such as the one we describe, has not been reported before. In the first 2 weeks of January 1992 our department isolated 5’. marcescens from sputum of 10 patients and all the strains had a similar antibiotic resistance pattern (resistant to ampicillin/amoxycillin, cephradine, trimethoprim, co-amoxiclav, cefuroxime and azlocillin, but sensitive to gentamicin, cefotaxime, ciprofloxacin, aztreonam and imipenem). None of the patients was severely ill and all of them were suffering from COAD. It was difficult to pinpoint any new serious signs or symptoms. On investigation it became known that all affected patients were receiving nebulized medication (salbutamol and/or ipratropium diluted with saline 0.9%) at the time when these isolations were made. Therefore, microbiological investigation included sampling of the nebulizers used by the patients and the diluent (i.e. saline and the saline bottle). S. marcescens strains with similar antibiogram were grown from all 10 nebulizers, saline and from inside of the bottle top. Samples of salbutamol and ipratropium were also cultured but found to be sterile. On enquiry into the nursing practices, it was found that the diluent (i.e. 0.9% saline), instead of being fed direct from sterile sachets into the nebulizers, was stored in a sterile bottle, which acted as a reservoir. Required saline from the bottle was subsequently fed into the nebulizers already charged with medication (i.e. salbutamol/ipratropium) through a sterile syringe. The reservoir was stored at room temperature, opened and used on a number of occasions throughout the day. As the saline was used, fresh sterile saline from a new sachet was used to top it up. Nebulizers were used exclusively on an individual basis. It was noted that the practice of taking an aliquot of medication from multi-dose vials of salbutamol or ipratropium, and diluting with sterile saline instead of using single-dose ‘nebules’, was approved in the nursing manual, but not the daily topping up of saline. Single-dose ‘nebules’, ready for use without dilution, would be more expensive. The isolates from the patients as well as from saline and the nebulizers were sent to the Division of Hospital Infection, Central Public Health Laboratory, Colindale, UK. They were all 014 serotype and belonged to the same phage type. The ward staff were immediately advised that a fresh sachet of saline should be used each time a nebulized medication is to be administered and any remaining solution discarded immediately. It was also emphasized that
Letters
170
to the Editor
nebulizers should be washed with detergent and hot water, and stored dry until the next use. No further cases have been reported since this advice was given. A. K. Chaudhuri C. F. Booth
Department of Microbiology and Infection Control, Royal Albert Edward Infirmary, Wigan WNl ZNN UK
Sir, An outbreak
of EMRSA
2 associated medical
with staff
long-term
colonization
of
We wish to report a small outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection of central venous lines associated with long-term colonization of a member of the medical staff. Two patients became infected with MRSA on central venous catheter tips over a period of 1 month. The first patient, a 68-year-old man, had had an oesophago-gastrectomy. The central venous catheter had been inserted in theatre and was removed on the second postoperative day. No MRSA was isolated from skin, throat, blood or sputum. The second patient was a 63-year-old man who had undergone vascular surgery. The catheter had been inserted in theatre and was removed on the 5th postoperative day and sent for culture when the patient became pyrexial. The exit site of the catheter was inflamed and flucloxacillin was commenced pending culture results. Subsequent skin and throat swabs were taken which also grew MRSA. This patient had been screened for MRSA on three occasions during his preoperative assessment and immediately prior to his operation. No MRSA had been isolated. The MRSA isolates from these patients were identified as EMRSA 2 by phage typing at the Central Public Health Laboratory (Cohndale, UK) (phage 80 and 85 and experimental phages 90 and 932).’ No previous isolates of this strain had been found at this hospital. We undertook extensive screening of staff and patients in an attempt to identify the source of this outbreak. A member of the medical staff who had been present at both operations was found to be a carrier of an indistinguishable strain of EMRSA 2. This was isolated from his nose, throat, forehead, hands and axillae but not from his groin. No other members of staff or patients were found to carry MRSA. This doctor had not inserted either of the central venous lines, however he had used them to administer drugs. He had recently started working at this hospital, so the earlier epidemiology of this strain was sought. His previous
169
to the Editor
Sir,
Outbreak
of chest infections
with
Serratia
marcescens
We report an iatrogenic outbreak of chest infection with Serratia marcescens in an acute medical ward housing mostly patients with respiratory disorders. Ten patients out of a total of 23 in the ward were affected, within a span of 2 weeks, most of them suffered primarily from chronic obstructive airways diseases (COAD). As far as we know, a common source outbreak of S. marcescens, such as the one we describe, has not been reported before. In the first 2 weeks of January 1992 our department isolated 5’. marcescens from sputum of 10 patients and all the strains had a similar antibiotic resistance pattern (resistant to ampicillin/amoxycillin, cephradine, trimethoprim, co-amoxiclav, cefuroxime and azlocillin, but sensitive to gentamicin, cefotaxime, ciprofloxacin, aztreonam and imipenem). None of the patients was severely ill and all of them were suffering from COAD. It was difficult to pinpoint any new serious signs or symptoms. On investigation it became known that all affected patients were receiving nebulized medication (salbutamol and/or ipratropium diluted with saline 0.9%) at the time when these isolations were made. Therefore, microbiological investigation included sampling of the nebulizers used by the patients and the diluent (i.e. saline and the saline bottle). S. marcescens strains with similar antibiogram were grown from all 10 nebulizers, saline and from inside of the bottle top. Samples of salbutamol and ipratropium were also cultured but found to be sterile. On enquiry into the nursing practices, it was found that the diluent (i.e. 0.9% saline), instead of being fed direct from sterile sachets into the nebulizers, was stored in a sterile bottle, which acted as a reservoir. Required saline from the bottle was subsequently fed into the nebulizers already charged with medication (i.e. salbutamol/ipratropium) through a sterile syringe. The reservoir was stored at room temperature, opened and used on a number of occasions throughout the day. As the saline was used, fresh sterile saline from a new sachet was used to top it up. Nebulizers were used exclusively on an individual basis. It was noted that the practice of taking an aliquot of medication from multi-dose vials of salbutamol or ipratropium, and diluting with sterile saline instead of using single-dose ‘nebules’, was approved in the nursing manual, but not the daily topping up of saline. Single-dose ‘nebules’, ready for use without dilution, would be more expensive. The isolates from the patients as well as from saline and the nebulizers were sent to the Division of Hospital Infection, Central Public Health Laboratory, Colindale, UK. They were all 014 serotype and belonged to the same phage type. The ward staff were immediately advised that a fresh sachet of saline should be used each time a nebulized medication is to be administered and any remaining solution discarded immediately. It was also emphasized that
Letters
170
to the Editor
nebulizers should be washed with detergent and hot water, and stored dry until the next use. No further cases have been reported since this advice was given. A. K. Chaudhuri C. F. Booth
Department of Microbiology and Infection Control, Royal Albert Edward Infirmary, Wigan WNl ZNN UK
Sir, An outbreak
of EMRSA
2 associated medical
with staff
long-term
colonization
of
We wish to report a small outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection of central venous lines associated with long-term colonization of a member of the medical staff. Two patients became infected with MRSA on central venous catheter tips over a period of 1 month. The first patient, a 68-year-old man, had had an oesophago-gastrectomy. The central venous catheter had been inserted in theatre and was removed on the second postoperative day. No MRSA was isolated from skin, throat, blood or sputum. The second patient was a 63-year-old man who had undergone vascular surgery. The catheter had been inserted in theatre and was removed on the 5th postoperative day and sent for culture when the patient became pyrexial. The exit site of the catheter was inflamed and flucloxacillin was commenced pending culture results. Subsequent skin and throat swabs were taken which also grew MRSA. This patient had been screened for MRSA on three occasions during his preoperative assessment and immediately prior to his operation. No MRSA had been isolated. The MRSA isolates from these patients were identified as EMRSA 2 by phage typing at the Central Public Health Laboratory (Cohndale, UK) (phage 80 and 85 and experimental phages 90 and 932).’ No previous isolates of this strain had been found at this hospital. We undertook extensive screening of staff and patients in an attempt to identify the source of this outbreak. A member of the medical staff who had been present at both operations was found to be a carrier of an indistinguishable strain of EMRSA 2. This was isolated from his nose, throat, forehead, hands and axillae but not from his groin. No other members of staff or patients were found to carry MRSA. This doctor had not inserted either of the central venous lines, however he had used them to administer drugs. He had recently started working at this hospital, so the earlier epidemiology of this strain was sought. His previous
