Pedro B., Teles L., Cabral L, Cruzeiro C.

Plastic and Reconstructive Surgery Service and Burns Unit, Coimbra University Hospitals, Portugal

SUMMARY. Acinetobacter is a gram-negative bacteria of the Neisseriaceae family. A very rare strain of multiresistant Acinetobacter baumanii was identified in the Burns Unit of Coimbra University Hospitals (Portugal) in January and February 1999. This infectious episode involved 11 patients and made it necessary to take strong hygiene and isolation measures.

Introduction

Acinetobacter is a saprophyte bacteria found in live organisms and inanimate beings.1 About 25% of people are healthy carriers. Owing to its scarce virulence, the great majority of infections are produced in the hospital environment,2 with a greater incidence in patients who are seriously ill and even in a critical state, with central venous lines, vesicle probes, mechanical ventilation, etc.3 Acinetobacter can also be found in the soil, water, pasteurized milk, frozen food, hospital air-conditioning systems, water deposits, dialysis fluids, hospital mattresses, humidifiers, and oxygen systems.

The close relationship between Acinetobacter bacteriaemia and/or sepsis and surgical procedures or permanent venous lines suggests that the skin is one of the main entrances for this micro-organism.3 The great incidence of Acinetobacter pneumonia as a primary infection or superinfection indicates that the airways can be a further path for bacterial contamination.4 Acinetobacter can also be found in urethral, vaginal, and conjunctival secretions, expectoration, blood, pleural fluid, cerebrospinal fluid, synovial fluid, ascitic fluid, stools, skin ulcers, abscesses, etc.

Relevant factors in the pathogenesis of Acinetobacter infections include the patient’s age; previous treatment with wide spectrum antibiotics, steroids, cytostatics, and immunosuppressors; parenteral nutrition; and admission to ICUs, burn units, etc.

The most important infections caused by Acinetobacter are meningitis, acute and subacute bacterial endocarditis, pneumonia, genitourinary infections, sepsis, peritonitis, corneal ulcers, hepatic and pancreatic abscesses, oral abscesses, and soft tissue infections.

For the diagnosis of Acinetobacter infections it has to be isolated from blood, cerebrospinal fluid, expectoration, urine, or pus. Tests of bacterial sensibility to antibiotics should always be performed.

Patients and method

The Burns Unit of Coimbra University Hospitals has 10 rooms and receives burn patients from all over Portugal. Each patient is isolated and adequately monitored.

In the months of January and February 1999, the Burns Unit admitted 11 patients in whom infections by multiresistant Acinetobacter were found. As normal, all the patients’ antibiotherapy was guided by tests of bacterial sensibility to antibiotics. These tests demonstrated the presence of resistance to penicillin, ampicillin, cephalosporins, imipenem, piperacilin-tazobactan, polymixine, ciprofloxacin, amycacin and gentamicin. Some intermediate sensibility to tobramycin was found in five patients.

Apart from the therapies instituted in each patient in whom infection was found, the following strict hygiene measures were taken without delay for the prevention of dissemination:

1. total isolation of the patient;
2. compulsory use of gown, cap, facial masks, foot covers, and sterilized gloves by health personnel during contact with the affected patients;
3. maintenance of the same clinical instruments exclusively to each room until the affected patient’s discharge from hospital, followed by compulsory sterilization (e.g. stethoscope, sphygmomanometer, thermometer);
4. exclusive cleaning material for each room;
5. use of an association of aldehyde and formol (1% concentration) as antiseptic and disinfectant;
6. cleaning of room surfaces every 8 h with aldehyde-formol solution (this is the solution’s active period);
7. cleaning of all medical apparatus in common use (X-rays equipment, endoscopes, etc.) with the antiseptic solution before removal from affected rooms;
8. patient hygiene with chlorhexidine solution;
9. closing of rooms for some hours after discharge from hospital of affected patients before thorough cleaning and disinfecting in order to allow bacteria to deposit on the surfaces.

Results

Out of a total of 11 patients admitted to the burns unit where Acinetobacter infection had developed:

• there were 5 males and 6 females;
• 9 patients had been transferred from other hospitals (4 males and 5 females);
• 7 patients had associated pathologies (2 males and 1 female with cardiorespiratory pathology, 1 male with type II diabetes, 1 female with colon neoplasia, 1 female with brain neoplasia, and 1 female with schizophrenia).

Of the 5 male patients:

• 3 were discharged from hospital;
• 1 was transferred to another burns unit in Spain, where he died;
• 1 died in the Coimbra Burns Unit.

Of the 6 female patients:

• 2 were discharged from hospital;
• 4 died in the Coimbra Burns Unit.

The total burned body surface area ranged from 8.5% to 70%.

The patients’ age range was from 22 to 90 years.

Discussion

Multiresistant Acinetobacter infections are not unknown in burns units. The problem of nosocomial infections is summed up in the concept of a vulnerable host placed in a hostile environment.2

The interaction between host and micro-organism defines the clinical outcome and is influenced by many factors (metabolic, nutritional, therapeutic, etc.).

When nosocomial infections arise, they complicate patient evolution, lengthen convalescence, and increase economic costs, morbidity, and mortality.

RESUME L’Acinetobacter est une bactérie à Gram négatif de la famille Neisseriaceae. Les Auteurs ont identifié une souche très rare d’Acinetobacter baumanii dans l’Unité des Brûlures des Hôpitaux Universitaires de Coimbra (Portugal) en janvier et février 1999. Cet épisode d’infection a intéressé 11 patients et il a été nécessaire de prendre des mesures sévères d’hygiène et d’isolement.

Bibliography

1. Harrison and Petersdorf: “Princípios de Medicina Interna”, 11th edition, vol. l, 548, 1998.
2. Alexander J.W.: Nosocomial infections. Curr. Prob. Surg., 1-3: August, 1973.
3. Hallen D.M., Hartman B.J..: Acinectobacter species. In: “Principles and Practice in Infectious Diseases”, Mandell, Douglas, Bennett, 1998-2027, 1979.
4. Mareos, Vila, Jiménez: Epidemiologia de las Infecciones por Acinectobacter Baumanii. Enferm. Infecc. Microbiol. Clin., 2: 8, 1993.