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The laryngoscope as a potential source of cross-infection
Letters
to the Editor
6. Malchesky PS, Bond WW, Decker MD. Biological indicators sterilizer. Infect Control Hosp Epidemiol 1993; 14: 563-566.
315
for a liquid
chemical
Sir,
The laryngoscope
as a potential
source of cross-infection
We have recently seen four patients with serious Pseudomonas aeruginosa infections on our paediatric cardiac intensive care unit, one of whom died of nosocomial pneumonia and septicaemia having been expected to make a full recovery from the surgical procedure. All four isolates were of different phage types, but we were concerned that this unexpected cluster may reflect poor handling of an environmental source on the unit. On review, we found the control of infection practices were good. Ventilator humidifiers were sealed disposable units, moisture traps were drained by staff wearing gloves and ventilator tubing was changed every 48 h. Endotracheal suction was performed with single use cannulae by staff wearing gloves and suction jars had disposable inner linings. It was too late to look for faecal carriage in the patients but staff were aware of this potential source and the importance of handwashing. It was noted however that a laryngoscope blade had dried secretions around the bulb and on the blade. These areas were sampled with a moist swab and direct plating revealed a moderate growth of P. aeruginosa of the same phage type as the blood culture isolate from the child who died. The blade was sampled seven days after being used for this child. If it had been used during those seven days, it could only have been once for a child on admission who had no infected secretions. We were surprised that the organism could survive this long on a dry surface and were concerned that intubation with a contaminated laryngoscope could potentially seed the respiratory tract of an at-risk child. Three particular problems on this unit were revealed. The policy was that laryngoscope blades should be cleaned with detergent and then with an alcohol-impregnated wipe.’ In practice this had been reduced to the alcohol wipe only. The contaminated laryngoscope was the only small one on the unit. Repeat intubations on the unit were common since many patients were neonates whose narrow airways more easily block with secretions. It was recommended that a second small laryngoscope should be purchased. After each use the bulb and blade should be removed, all parts thoroughly washed and the laryngoscope soaked in 70% alcohol for 10 min and then dried. We could not prove that P. aeruginosa had been transmitted between patients by a laryngoscope, but no further infections with this strain have been seen in the six months since the introduction of the new
Letters
316
to the Editor
recommendation. Spot checks have noted clean, culture-negative ryngoscopes and confirmed that cleaning policies are being properly lowed. We would Laboratory,
like to thank the Laboratory of Hospital Colindale for typing these strains.
J. E. Foweraker
Infection
at the Central
Public
lafol-
Health
Leicester Public Health Laboratory, Sandringham Building, Leicester Royal Infirmary, Leicester LEl SWW, UK References
1. Ayliffe GAJ, Lowbury EJL, Geddes AM, Williams JD. Decontamination and the environment, equipment and the skin. In: Control of Hospital Infection. A Practical Handbook, 3rd edn. Chapman Hall Medical 1992; 78-114.
Sir, Iatrogenic
meningitis
by Streptococcus puncture
salivarius
following
lumbar
A 64-year-old male underwent a lumbar puncture for myelography because of back pain he had suffered for 15 years. In 1978 he underwent surgery for prolapse of a lumbar disc but he had no further history of major diseases. The night after the lumbar puncture the patient developed symptoms of meningitis, severe headache, stiff neck and high temperature. His leucocyte count rose to 22.5 x 109L-‘. A new lumbar puncture was performed and the cerebrospinal fluid contained 10 000 leucocytes mmp3, mainly polymorphonuclear leucocytes, and had a protein content of 5.4 gL-‘. Culture yielded a Streptococcus salivarius as identified by API 20 streptest. This the patient was treated with isolate was designated isolate 1. Initially flucloxacillin and ceftriaxone. After identification of the causative organism, therapy was changed to penicillin. To identify the source of the infection the procedures during myelography were reviewed and throat swabs taken from the neurologist and his assistant yielded Streptococcus salivarius (designated isolates 2 and 3). Isolate 1 and 2 showed an identical profile in the API 20 streptest (APl No. 5050411). Isolate 2 was identified as API No. 5070651. Fatty acid analysis performed by Dr A. van Silfhout of the National Institute for Public Health and Environmental Hygiene, the Netherlands showed comparable results. Fatty acid profiles from isolates 1 and 2 had an Euclidian distance of ~2 indicating a single source. The Euclidian distance of the profile from isolate 3 was 2-6, which suggests the same subspecies but a different strain.
to the Editor
6. Malchesky PS, Bond WW, Decker MD. Biological indicators sterilizer. Infect Control Hosp Epidemiol 1993; 14: 563-566.
315
for a liquid
chemical
Sir,
The laryngoscope
as a potential
source of cross-infection
We have recently seen four patients with serious Pseudomonas aeruginosa infections on our paediatric cardiac intensive care unit, one of whom died of nosocomial pneumonia and septicaemia having been expected to make a full recovery from the surgical procedure. All four isolates were of different phage types, but we were concerned that this unexpected cluster may reflect poor handling of an environmental source on the unit. On review, we found the control of infection practices were good. Ventilator humidifiers were sealed disposable units, moisture traps were drained by staff wearing gloves and ventilator tubing was changed every 48 h. Endotracheal suction was performed with single use cannulae by staff wearing gloves and suction jars had disposable inner linings. It was too late to look for faecal carriage in the patients but staff were aware of this potential source and the importance of handwashing. It was noted however that a laryngoscope blade had dried secretions around the bulb and on the blade. These areas were sampled with a moist swab and direct plating revealed a moderate growth of P. aeruginosa of the same phage type as the blood culture isolate from the child who died. The blade was sampled seven days after being used for this child. If it had been used during those seven days, it could only have been once for a child on admission who had no infected secretions. We were surprised that the organism could survive this long on a dry surface and were concerned that intubation with a contaminated laryngoscope could potentially seed the respiratory tract of an at-risk child. Three particular problems on this unit were revealed. The policy was that laryngoscope blades should be cleaned with detergent and then with an alcohol-impregnated wipe.’ In practice this had been reduced to the alcohol wipe only. The contaminated laryngoscope was the only small one on the unit. Repeat intubations on the unit were common since many patients were neonates whose narrow airways more easily block with secretions. It was recommended that a second small laryngoscope should be purchased. After each use the bulb and blade should be removed, all parts thoroughly washed and the laryngoscope soaked in 70% alcohol for 10 min and then dried. We could not prove that P. aeruginosa had been transmitted between patients by a laryngoscope, but no further infections with this strain have been seen in the six months since the introduction of the new
Letters
316
to the Editor
recommendation. Spot checks have noted clean, culture-negative ryngoscopes and confirmed that cleaning policies are being properly lowed. We would Laboratory,
like to thank the Laboratory of Hospital Colindale for typing these strains.
J. E. Foweraker
Infection
at the Central
Public
lafol-
Health
Leicester Public Health Laboratory, Sandringham Building, Leicester Royal Infirmary, Leicester LEl SWW, UK References
1. Ayliffe GAJ, Lowbury EJL, Geddes AM, Williams JD. Decontamination and the environment, equipment and the skin. In: Control of Hospital Infection. A Practical Handbook, 3rd edn. Chapman Hall Medical 1992; 78-114.
Sir, Iatrogenic
meningitis
by Streptococcus puncture
salivarius
following
lumbar
A 64-year-old male underwent a lumbar puncture for myelography because of back pain he had suffered for 15 years. In 1978 he underwent surgery for prolapse of a lumbar disc but he had no further history of major diseases. The night after the lumbar puncture the patient developed symptoms of meningitis, severe headache, stiff neck and high temperature. His leucocyte count rose to 22.5 x 109L-‘. A new lumbar puncture was performed and the cerebrospinal fluid contained 10 000 leucocytes mmp3, mainly polymorphonuclear leucocytes, and had a protein content of 5.4 gL-‘. Culture yielded a Streptococcus salivarius as identified by API 20 streptest. This the patient was treated with isolate was designated isolate 1. Initially flucloxacillin and ceftriaxone. After identification of the causative organism, therapy was changed to penicillin. To identify the source of the infection the procedures during myelography were reviewed and throat swabs taken from the neurologist and his assistant yielded Streptococcus salivarius (designated isolates 2 and 3). Isolate 1 and 2 showed an identical profile in the API 20 streptest (APl No. 5050411). Isolate 2 was identified as API No. 5070651. Fatty acid analysis performed by Dr A. van Silfhout of the National Institute for Public Health and Environmental Hygiene, the Netherlands showed comparable results. Fatty acid profiles from isolates 1 and 2 had an Euclidian distance of ~2 indicating a single source. The Euclidian distance of the profile from isolate 3 was 2-6, which suggests the same subspecies but a different strain.