Evidence-based infection control in the ICU (except catheters)

Potential of metagenomic next-generation sequencing in detecting infections of ICU patients

BACKGROUND

Due to the limitations of traditional microbiological detection techniques in evaluating complicated infections in ICU patients, it is necessary to explore novel and effective methods to improve the clinical detection of ICU patients' infections.

OBJECTIVE

This study aimed to evaluate the efficiency and specificity of mNGS in screening pathogens in the blood, deep phlegm, urine, and other sample types of ICU patients exploring an effective method for infection detection.

METHODS

A total of 56 ICU patients with 131 samples were included in this study. The sample types included blood, deep phlegm, urine, drainage, anal swabs, and other types. Samples were analyzed by both conventional detection method and mNGS tests. The diagnosis efficiency and consistency of the two methods were compared. The distribution of the identified pathogens was analyzed. Moreover, the clinical features of patients with mNGS-positive or mNGS-negative results were compared.

RESULTS

The positive rate of mNGS was 81.7% (107/131) including 3.1% (4/131) weakly positive, while the positive rate of traditional detection was only 30.5%, including 29 strong positive results and 11 weak positive results. Additionally, there were 41 patients chose to adjust anti-infection strategies according to the results of mNGS, which significantly saved treatment costs. The mNGS-positive patients showed a shorter ICU hospitalization and higher intention to adjust anti-infection strategies than the mNGS-negative patients.

CONCLUSION

mNGS is of great potential for the pathogen detection of ICU patients, and has a higher detection rate than traditional detection methods. Further clinical application investigations can be carried out to expand the application of mNGS.

Antimicrobial resistance in the intensive care unit: mechanisms, epidemiology, and management of specific resistant pathogens

Infections caused by drug-resistant and multidrug-resistant microbial pathogens pose tremendous challenges to health care systems, including challenges related to the diagnosis, treatment, and containment of these infections. These challenges are amplified in the intensive care unit (ICU), where pressures for selection and emergence of resistance and risks of transmission of resistant pathogens are highest, and where the threat of resistance drives selection of empiric antimicrobial regimens. This article reviews basic concepts of resistance to antibacterial agents including mechanisms and modes of transmission, and discusses management issues for the important drug-resistant pathogens found in the ICU.

Antimicrobial susceptibility pattern of microorganisms involved in the pathogenesis of surgical site infection (SSI); A 1 year of surveillance

The aim of this study is to identify the antibiotic sensitivity pattern of pathogens involved in the process of surgical site infection, in surgical wards. Changes made in the pattern of antibiotic use will result in different microorganism susceptibility patterns, which needs correct determination for precise empiric antibiotic therapy. One thousand patients (62% men and 38% women, 18- 74-years-old, with mean age 43 +/- 8)) who underwent surgical treatment, in Alzahra University Hospital, Isfahan University of Medicine, Isfahan, Iran, were studied from 2005 to 2006. Surgical wound infections, based on the reported criteria, were aspirated for culturing within 1 plus gram staining of prepared smears. Minimum Inhibitory Concentrations (MICs) were determined for samples and all derived data were compared by SPSS 13 and WHO net 5 software. The prevalence of SSI was 13.3% with 150 positive cultures, totally. Of 150 bacteria, isolated from surgical site infections Staphylococcus aureus had most frequency (43%). Resistance of isolated organisms was 41.7% in amikacin, 65 and 78.6% in ceftazidime, 85.7% in ceftriaxone, 61.5% in ciprofloxacin, 78.8% in gentamicine, 6.4% in imipenem, 13% in meropenem and 70.6% in trimethoprim/sulfamethoxazole, respectively. 78.9% of Staphylococcus aureus isolates were MRSA and vancomycine was the most effective antibiotic without any resistance. Among 10 isolates of coagulase negative Staphylococcus, no vancomycine resistance was seen, but in contrast all cases were resistant to oxacillin. The most common gram negative organism was Klebsiella (18 isolates) in which 100 and 80% were sensitive to imipenem and meropenem, respectively. Seventeen cases were E. coli, in which the most sensitivity was to meropenem (80%) and imipenem (77.8%). Thirteen cases of Pseudomonas were detected, in which 16.7% were resistant to imipenem and 8.3% to meropenem. Our results demonstrated that the total antibiotic resistance is increasing among SSIs, with an up sloping pattern, which will contact with a constant empiric antibiotic therapy. So, precise up to date antibiogram tantalize us toward balancing the rate of total antibiotic resistance to SSIs.

Acquisition and spread of Acinetobacter baumannii and Stenotrophomonas maltophilia in intensive care patients

Acinetobacter baumannii and Stenotrophomonas maltophilia are increasingly important pathogens, especially in the intensive care units (ICUs). This study was designed to investigate the clonality, the mode of transmission and the patients' risk profile for acquisition of A. baumannii and S. maltophilia at the ICU of an Italian Hospital. Patterns of A. baumannii and S. maltophilia acquisition in the ICU during the period of the survey were carriage, colonization and infection. Characterization of A. baumannii was performed by ARDRA and genotyping of both pathogens by PFGE. Our study provided evidence for the occurrence of an outbreak sustained by the two organisms in study involving 27.3% of patients enrolled into the surveillance. The spread of a unique A. baumannii epidemic clone was demonstrated. A major clone of S. maltophilia was responsible for the epidemic spread of S. maltophilia (55.5% of isolates), thus confirming A. baumannii cross-transmission and showing--among few published reports--the clonal spread of S. maltophilia. Outliers analysis suggested colonized patients as the probable epidemic sources. Mechanical ventilation was confirmed as risk factor for infection (OR 8.4; 95%C.I.: 2.6-27.5). A multimodal intervention program was introduced, followed in later months with a drastic restriction of infection and colonization due to A. baumannii and S. maltophilia and subsequently with the successful control of the outbreak. Active surveillance of infection and colonization by high-risk clones, together with implementation of control strategies, including strict hand hygiene, proved to be effective to reduce the epidemic spread of both alert pathogens in our ICU.