Outbreak of nosocomial Acinetobacter baumannii bacteremia in a high risk ward

Infections in pediatric patients with hematologic malignancies

Despite significant advances in supportive care, infection remains second only to malignancy as a cause of death in pediatric oncology patients, and infection accounts for a large fraction of treatment-related costs. Multiple risk factors contribute to infection-related morbidity, chief among them the immunosuppressive effects of leukemia itself and of cytotoxic chemotherapy, prolonged hospitalization and antibiotic use, and loss of barrier integrity associated with mucositis and the need for indwelling central access. While viruses are the most common causes of infection, bacteria are responsible for most life-threatening complications. Gram-negative bacilli are a concern for all patients undergoing treatment, while a subset of gram-positive organisms, particularly viridans streptococci, become significant pathogens in children receiving profoundly immunosuppressive therapy. Invasive fungal infections are also a serious risk for morbidity and mortality in this population. Availability of new antimicrobial agents has made it possible to treat infectious complications more effectively, but their availability is also leading to an increased prevalence of highly resistant pathogens. Future work in pediatric oncology will need to include measures to reduce the immunosuppressive effects of anti-cancer therapy, provide targeted treatment for infections, and better identify groups of patients at high risk for infectious complications, who may benefit from antimicrobial prophylaxis or more aggressive empirical therapy.

Hospital-acquired infections related to contaminated substances

Drug-related outbreaks are frequently reported from various medical departments. A systematic review was performed to describe characteristics of these outbreaks and to determine the most frequent occasions in which contamination of substances for patient care take place. Articles were assessed by a search of the outbreak database, a search of PubMed, and hand search of reference lists from relevant articles. Articles published before 1990 were excluded. Data on affected patients, hospital-acquired infections, substances, pathogens and graded information about the location of the contamination incidence were extracted. A total of 2250 patients in 128 articles were included, mostly from intensive care units or haematological departments. Septicaemia was the most frequent hospital-acquired infection. Most often articles report contamination of blood products and heparin-sodium chloride solutions. The most frequent pathogens were hepatitis A virus, Yersinia enterocolitica, and Serratia spp. for blood products and Burkholderia cepacia and Enterobacter spp. for substances other than blood products. Mortality was highest if red blood cells or total parenteral nutrition formulas were contaminated. In 64 of the outbreaks multi-dose vials had been used against the manufacturers' recommendations. Thus, drug-related outbreaks are likely to occur particularly when basic hygiene measures are disobeyed. A large proportion of drug-related nosocomial infections could have been prevented, for example, by avoiding the use of multi-dose vials.

Prevalence and antimicrobial patterns of Acinetobacter baumannii on hands and nares of hospital personnel and patients: the iceberg phenomenon again

OBJECTIVE

To determine the prevalence and antimicrobial susceptibility patterns of Acinetobacter baumannii on the hands and nares of health care workers and patients from intensive care and rehabilitation units at two hospitals in northern Manhattan, New York.

DESIGN

Prevalence survey of Acinetobacter on the hands and anterior nares of staff (n = 184) and patients (n = 98) in rehabilitation and intensive care units of two hospitals.

RESULTS

Twenty subjects (7.1%) had positive test results for A baumannii (6 staff [3.3%] and 14 patients [14.3%]). Five patients had positive test results at both sites, four in the nares only, and 11 on hands only. Among patients, four significant predictors of A baumannii were days on unit (P = .003), location (hospital A or B) (P = .01), surgery (P = .04), and receiving an antifungal agent (P = .02; OR, 5.6; 95% CI, 1.25-24.52). Among staff, predictors were skin damage (P = .02) and employment in hospital B (P = .03). Nine of the 20 subjects (45%) had positive test results for multiresistant strains, one from a staff member and eight from patients.

CONCLUSION

Patients whose conditions are not clinically symptomatic for A baumannii, as well as staff, are often colonized. Staff with damaged skin are more likely to be colonized. Control of this organism will only be possible when the principle of the iceberg phenomenon--all patients (and staff) treated with standard, Universal Precautions--is strictly followed. Further, the endemic prevalence of multiresistant strains may be higher than previously appreciated.

Antibiotic resistance in hospital pathogens--acquisition or spread?

Hospital resistant pathogens are a problem of hospital use allowing acquisition of multi-resistant strains. The use of antibiotics in the community and on the farm has little impact on hospital infection rates and prevalence of resistance in hospital bacteria. Once acquisition occurs the main problem is spread of clones to highly vulnerable patients. Attention to protective methods for such patients ought to be a priority in hospital infection control.

Monoclonal antibodies against the iron regulated outer membrane Proteins of Acinetobacter baumannii are bactericidal

BACKGROUND

Iron is an important nutrient required by all forms of life.In the case of human hosts,the free iron availability is 10(-18) M,which is far less than what is needed for the survival of the invading bacterial pathogen. To survive in such conditions, bacteria express new proteins in their outer membrane and also secrete iron chelators called siderophores. RESULTS/ DISCUSSION: Acinetobacter baumannii ATCC 19606, a nosocomial pathogen which grows under iron restricted conditions, expresses four new outer membrane proteins,with molecular weight ranging from 77 kDa to 88 kDa, that are called Iron Regulated Outer Membrane Proteins (IROMPs). We studied the functional and immunological properties of IROMPs expressed by A.baumanii ATCC 19606. The bands corresponding to IROMPs were eluted from SDS-PAGE and were used to immunize BALB/c mice for the production of monoclonal antibodies. Hybridomas secreting specific antibodies against these IROMPs were selected after screening by ELISA and their reactivity was confirmed by Western Blot. The antibodies then generated belonged to IgM isotype and showed bactericidical and opsonising activities against A.baumanii in vitro. These antibodies also blocked siderophore mediated iron uptake via IROMPs in bacteria.

CONCLUSION

This proves that iron uptake via IROMPs,which is mediated through siderophores,may have an important role in the survival of A.baumanii inside the host,and helps establishing the infection.