Infection with Acinetobacter in a burns unit

Systematic review of invasive Acinetobacter infections in children

INTRODUCTION

Clinicians are generally familiar with Acinetobacter as an etiological agent for serious nosocomial infections in intensive care units. However, there are no previous reviews of the full spectrum of invasive infections in children.

METHODS

A systematic review of the literature was completed up to December 2008 for reports of invasive Acinetobacter infections in children.

RESULTS

There were 101 studies that met the inclusion criteria including 18 possible outbreaks, 33 case series and 49 case reports. Suspected outbreaks were concentrated in neonatal intensive care units (16 of 18 outbreaks) and involved bacteremia or meningitis. Proof of isolate clonality or identification of the source of the outbreak was seldom established. Case series were primarily of children younger than five years of age presenting with bacteremia (sometimes multiresistant), meningitis, endocarditis or endophthalmitis, with many community-acquired infections being reported from India. Case reports consisted of unique presentations of disease or the use of novel therapies. Attributable mortality in the outbreaks and case series combined was 68 of 469 (14.5%).

DISCUSSION

Invasive Acinetobacter infections in children usually manifest as bacteremia, meningitis or both, but can result in a wide variety of clinical presentations. Outbreaks are primarily a problem in newborns with underlying medical conditions. Most reports of community-acquired infections are from tropical countries. The study of the mechanism of colonization and infection of children in intensive care units and of neonates in tropical countries may provide some insight into prevention of invasive infections.

Changing trends in bacteriology of burns in the burns unit, Delhi, India

A retrospective study of bacterial isolates from the wounds of patients admitted to burns unit, was undertaken at Guru Tegh Bahadur Hospital, University College of Medical Sciences, Delhi, India, over a period of 5 years between July 1997 and April 2002. The study compared the results obtained with the previous 5 years data (June 1993-June 1997) from the same unit to determine the changing patterns and emerging trends of bacterial isolates and their antimicrobial susceptibilities. Pseudomonas species (31%) and Staphylococcus aureus (22%) were the most common pathogens followed by Klebsiella species (19%). Multi-drug resistant (MDR) Acinetobacter species (9%) have emerged as an important nosocomial pathogen in our burn unit. Most of the gram-negative isolates obtained were found to be multi-drug resistant and 61% of the tested isolates were extended spectrum beta-lactamase (ESBL) producers. Concomitant resistance to penicillin and aminoglycosides was observed in 61% of Enterococcus fecalis isolates. When compared with the results of previous 5 years (June 1993-June 1997) Pseudomonas spp. was still the commonest pathogen in the burns unit. However, isolation of this organism and other gram-negative organisms has decreased in comparison to previous years. The incidence of antimicrobial resistance has markedly increased over the past years resulting in limitation of therapeutic options.

An outbreak due to multiresistant Acinetobacter baumannii in a burn unit: risk factors for acquisition and management

OBJECTIVES

To describe the investigation and management of an outbreak due to multiresistant Acinetobacter baumannii and to determine risk factors for acquisition of the organism.

SETTING

A 14-bed regional burn unit in a Canadian tertiary-care teaching hospital.

DESIGN

Case-control study with multivariate analysis of potential risk factors using logistic regression analysis. Surveillance cultures were obtained from the hospital environment, from noninfected patients, and from healthcare providers.

RESULTS

A total of 31 (13%) of 247 patients with acute burn injuries acquired multiresistant A. baumannii between December 1998 and March 2000; 18 (58%) of the patients were infected. The organism was recovered from the hospital environment and the hands of healthcare providers. Significant risk factors for acquisition of multiresistant A. baumannii were receipt of blood products (odds ratio [OR], 10.8; 95% confidence interval [CI95], 3.4 to 34.4; P < .001); procedures performed in the hydrotherapy room (OR, 4.1; CI95, 1.3 to 13.1; P = .02); and increased duration of mechanical ventilation (OR, 1.1 per day; CI95, 1.0 to 1.1; P= .02).

INTERVENTIONS

Improved compliance with hand hygiene, strict patient isolation, meticulous environmental cleaning, and temporary closure of the unit to new admissions.

CONCLUSIONS

Acquisition of multiresistant A. baumannii was likely multifactorial, related to environmental contamination and contact with transiently colonized healthcare providers. Control measures addressing these potential sources of multiresistant A. baumannii were successful in terminating the outbreak. Ongoing surveillance and continued attention to hand hygiene and adequate environmental cleaning are essential to prevent recurrent outbreaks due to antibiotic-resistant bacteria in burn units.

Infrequent isolation of multiresistant Acinetobacter baumannii from the staff tending a colonized patient with severe burns

A patient with severe burns who was colonized by multiresistant Acinetobacter baumannii was cared for in contact isolation by staff intensively trained on hospital hygiene. Of the 1,907 postexposure cultures from the staff and 425 environmental samples, only 0.7% and 4%, respectively, yielded this microorganism. These data show that strict hygienic measures may limit staff colonization and contamination of the environment byA baumannii.

Acinetobacter baumannii--an emerging nosocomial pathogen in the burns unit Manipal, India

A retrospective study on 113 patients admitted to the burns unit over a period of 12 months was undertaken to investigate the emerging trend of Acinetobacter baumannii infection. Wound infection with A. baumannii was seen in 13 (11.5%) patients. Of these six (46%) patients developed septicaemia with the same bacteria and five (38%) expired. The virulence of these bacteria, drug susceptibility pattern and its role as a nosocomial pathogen is discussed.

The distribution of Acinetobacter species in clinical culture materials

A total of 584 Acinetobacter strains were isolated from 420 patients from 12 different hospitals over a period of twelve months. Identification of strains at the species level was done according to the new taxonomy proposed by Bouvet and Grimont. A. baumannii strains were isolated most frequently (n = 426; 72.9%), followed by A. species 3 (n = 55), A. johnsonii (n = 29), and A. lwoffii (n = 21). Most isolates were recovered from respiratory tract specimens (n = 251; 42.9%), blood cultures (n = 116; 19.9%), wound swabs (n = 90; 15.4%), catheter tips (n = 75; 12.8%), and urinary tract specimens (n = 20; 3.4%). Strains belonging to species other than A. baumannii were isolated more frequently (n = 158; 27.1%) than previously reported, mainly from blood cultures, respiratory tract specimens, and central venous catheters.

The clinical significance of Acinetobacter baumannii in blood cultures

Acinetobacter baumannii was isolated from blood cultures in 31 patients in 4 intensive care units at a large teaching hospital over a period of 6 months. In 23 of these patients, Acinetobacter was also isolated from tracheal aspirates. Catheter-related infection could be identified as the cause of bacteremia in 14 cases, whereas pneumonia was present in only 6 cases. All patients were seriously ill and 7 (24%) died of their infection.

An outbreak of Acinetobacter calcoaceticus infection in a neonatal care unit

Between January and December 1988, 383 neonates were admitted to our neonatal intensive care unit. 1,991 swabs and blood cultures were tested bacteriologically. Among them 90 specimens obtained from 41 patients were positive for Acinetobacter calcoaceticus. During this period we discovered and treated three cases with A. calcoaceticus sepsis. Three additional cases had blood cultures positive for this bacterium without demonstrating any clinical signs of infection. There is good evidence that contaminated warm air humidifiers were the source of infection. A review of microbiological data for several months preceding the outbreak showed a definite increase in the presence of A. calcoaceticus. The affected neonates required specific antibiotic therapy and intensive care. All of them survived. Conditions favoring the spread of these generally non-pathogenic bacteria and modes of preventive measures are discussed. The necessity of continuous bacteriological surveillance and careful disinfection of intensive care equipment is emphasized.