Problems and solutions in hospital-acquired bacteraemia

Preventing nosocomial bloodstream infections (NBSIs) by implementing hospitalwide, department-level, self-investigations: A NBSIs frontline ownership intervention

BACKGROUND

Nosocomial bloodstream infections (NBSIs) are adverse complications of hospitalization. Most interventions focus on intensive care units. Data on interventions involving patients' personal care providers in hospitalwide settings are limited.

OBJECTIVE

To evaluate the impact of department-level NBSI investigations on infection incidence.

METHODS

Beginning in 2016, positive cultures, classified as suspected of being hospital acquired, were prospectively investigated by patients' unit-based personal healthcare providers using a structured electronic questionnaire. After analyzing the conclusions of the investigation, a summary was sent quarterly to the departments and to hospital management. NBSI rates and clinical data during a 5-year period (2014-2018) were calculated and compared before and after the intervention (2014-2015 versus 2016-2018), using interrupted time-series analysis.

RESULTS

Among 4,135 bloodstream infections (BSIs), 1,237 (30%) were nosocomial. The rate of NBSI decreased from 4.58 per 1,000 admissions days in 2014 and 4.82 in 2015, to 3.81 in 2016, 2.94 in 2017 and 2.86 in 2018. Following a 4-month lag after introducing the intervention, the NBSI rate per 1000 admissions dropped significantly by 1.33 (P = .04; 95% CI, -2.58 to -0.07). The monthly NBSI rate continued to decrease significantly by 0.03 during the intervention period (P = .03; 95% CI, -0.06 to -0.002).

CONCLUSIONS

Detailed department-level investigations of NBSI events performed by healthcare providers, increased staff awareness and frontline ownership and were associated with a decrease in NBSI rates hospitalwide.

Healthcare-associated Infection in Intensive Care Units: Overall Analysis of Patient Criticality by Acute Physiology and Chronic Health Evaluation IV Scoring and Pathogenic Characteristics

Objectives

To compare the predicted vs observed mortality rate, criticality, and length of stay of the patients with healthcare-associated infections (HAIs) in intensive care units (ICUs) of a tertiary health center through acute physiology and chronic health evaluation (APACHE) IV scoring. To analyze the drug sensitivity pattern of the isolated pathogen.

Design

This is a prospective observational study involving the patients admitted to various ICUs of a tertiary care teaching hospital. Among 1,229 patients who were admitted in the ICUs for a period of 2.5 months (74 days), 767 patients stayed beyond 48 hours. They were monitored and 87 of them who developed HAIs were included in the study. The organisms isolated from the infection site were identified, and the drug resistance pattern was reported as per standard guidelines. The patients were followed up till their discharge, and adequate details pertaining to the study were collected including demographic details and physiological and biochemical parameters to calculate APACHE IV score, length of stay, and prognosis.

Setting

Intensive care units of JSS Hospital, Mysuru, Karnataka, India.

Subjects/patients

All patients who developed HAI in ICUs.

Interventions

Nil.

Measurements and main results

The HAI rate observed in this study was 15.7%. Ventilator-associated pneumonia (VAP) was the most common type of infection. Klebsiella and Acinetobacter were the frequently isolated organisms. There was a high prevalence of drug resistance among these pathogens. The ICU mortality in infected patients was 21.83%, roughly twice as that of uninfected patients. The observed length of stay was 11.66 (±8.53) days.

Conclusion

Healthcare-associated infection was associated with long duration of ICU stay. There was a high prevalence of drug resistance to various antibiotics. Acute physiology and chronic health evaluation IV score was not found to be good scoring system to predict the mortality and length of stay in the patients who had HAI.

How to cite this article

Gunasekaran S, Mahadevaiah S. Healthcare-associated Infection in Intensive Care Units: Overall Analysis of Patient Criticality by Acute Physiology and Chronic Health Evaluation IV Scoring and Pathogenic Characteristics. Indian J Crit Care Med 2020;24(4):252–257.

Identification of carbapenemase-mediated resistance among Enterobacteriaceae bloodstream isolates: A molecular study from India

Acquired resistance in carbapenem-resistant Enterobacteriaceae (CRE) conferred by carbapenemases is a major concern worldwide. Consecutive, non-duplicate isolates of Escherichia coli (EC) and Klebsiella pneumoniae from clinically diagnosed bloodstream infections were screened for the presence of carbapenem resistance by standard disk-diffusion method and minimum inhibitory concentration breakpoints using the Clinical and Laboratory Standards Institute guidelines. Carbapenemase-encoding genes were amplified by polymerase chain reaction. Of 387 isolates (214 K. pneumoniae, 173 EC) tested, 93 (24.03%) were found to be CRE. Of these, 71 (76.3%) were positive for at least one tested carbapenemase gene. The frequency of carbapenemase genes was New Delhi metallo-β-lactamse-1 (65.6%), oxacillinase (OXA)-48 (24.7%), OXA-181 (23.6%), Verona integron-encoded metallo-β-lactamase (6.4%) and K. pneumoniae carbapenemase (2.1%). Our study identified presence of carbapenemases in a large proportion of CRE isolates. Delineation of resistance mechanisms is important in view of future therapeutics concerned with the treatment of CRE and for aiding control efforts by surveillance and infection control interventions.

Effect of a training programme on blood culture contamination rate in critical care

Blood culture contamination can occur from extraction to processing; its rate should not exceed 3%.

OBJECTIVE

To evaluate the impact of a training programme on the rate of contaminated blood cultures after the implementation of sample extraction recommendations based on the best evidence.

METHOD

Prospective before-after study in a polyvalent intensive care unit with 18 beds. Two phases were established (January-June 2012, October 2012-October 2015) with a training period between them. Main recommendations: sterile technique, surgical mask, double skin disinfection (70° alcohol and 2% alcoholic chlorhexidine), 70° alcohol disinfection of culture flasks and injection of samples without changing needles. Including all blood cultures of patients with extraction request.

VARIABLES

demographic, severity, pathology, reason for admission, stay and results of blood cultures (negative, positive and contaminated). Basic descriptive statistics: mean (standard deviation), median (interquartile range) and percentage (95% confidence interval). Calculated contamination rates per 100 blood cultures extracted. Bivariate analysis between periods.

RESULTS

Four hundred and eight patients were included. Eight hundred and forty-one blood cultures were taken, 33 of which were contaminated. In the demographic variables, severity, diagnosis and stay of patients with contaminated samples, no differences were observed from those with uncontaminated samples. Pre-training vs post-training contamination rates: 14 vs 5.6 per 100 blood cultures extracted (P=.00003).

CONCLUSION

An evidence-based training programme reduced the contamination of samples. It is necessary to continue working on the planning of activities and care to improve the detection of pollutants and prevent contamination of samples.

Risk Factors for Health Care-Associated Bloodstream Infections in a Neonatal Intensive Care Unit

Background

Healthcare-associated bloodstream infections (HCA-BSI) are a major cause of morbidity and mortality in neonatal intensive care units (NICUs).

Objectives

We aimed to determine the causative organisms and risk factors of HCA-BSIs in NICUs.

Methods

This study was performed between January 2011 and December 2014 in the neonatal intensive care unit of Dicle university, Turkey. The study consisted of 126 patients (infected group) with positive blood culture and 126 randomly selected patients (uninfected control group) with negative blood culture after four days of hospitalization.

Results

We found that the most common causative agents isolated from nosocomial infections (NIs) were 20.7% Staphylococcus epidermidis, 26.7% Klebsiella spp., and 13.3% Acinetobacter spp. Incidences of low gestational age, low birth weight, vaginal birth type, and long length of hospitalization were higher in the infected neonates than in the uninfected neonates. In the univariate analysis, surgical operation, ventriculoperitoneal shunt, use of umbilical catheter, nasogastric or orogastric tube, urinary catheter, mechanical ventilation, surfactant treatment, erythrocyte transfusion, plasma transfusion, thrombocyte transfusion, total parenteral nutrition infusion, intracranial hemorrhage, length of hospital stay, fifth-minute Apgar score, and total parenteral nutrition time were significantly associated with NIs. In the multiple logistic regression analysis, fifth-minute Apgar, use of erythrocyte transfusion and surgical operation were found as the independent risk factors for HCA-BSI.

Conclusions

This study determined the causative organisms and risk factors of HCA-BSIs in NICUs.

Patient- and Device-Specific Risk Factors for Peripherally Inserted Central Venous Catheter—Related Bloodstream Infections

Objective.

To determine the patient- and device-specific risk factors for hospital-acquired peripherally inserted central venous catheter–related bloodstream infections (PICC BSIs) in adult patients.

Design.

Nested case-control study.

Setting.

Barnes-Jewish Hospital, a 1,252-bed tertiary care teaching hospital.

Patients.

Adult patients with PICCs placed from January 1, 2006, through July 31, 2008.

Methods.

PICC BSI cases were identified using the National Healthcare Safety Network definition. Uninfected control patients with PICCs in place were randomly selected at a 3: 1 ratio. Patient- and device-related variables were examined using multivariate analysis.

Results.

The overall PICC BSI rate was 3.13 per 1,000 catheter-days. Independent risk factors for PICC BSIs included congestive heart failure (odds ratio [OR], 2.0 [95% confidence interval (CI), 1.26–3.17];P= .003), intra-abdominal perforation (OR, 5.66 [95% CI, 1.76–18.19];P= .004),Clostidium difficileinfection (OR, 2.25 [95% CI, 1.17–4.33];P= .02), recent chemotherapy (OR, 3.36 [95% CI, 1.15–9.78];P= .03), presence of tracheostomy (OR, 5.88 [95% CI, 2.99–11.55];P< .001), and type of catheter (OR for double lumen, 1.89 [95% CI, 1.15–3.10];P= .01; OR for triple lumen, 2.87 [95% CI, 1.39–5.92];P= .004). Underlying chronic obstructive pulmonary disease (OR, 0.48 [95% CI, 0.29–0.78];P= .03) and admission to surgical (OR, 0.43 [95% CI, 0.24–0.79];P= .006) or oncology and orthopedic (OR, 0.35 [95% CI, 0.13–0.99];P= .05) services were less likely to be associated with having a PICC BSI.

Conclusions.

We identified several novel factors related to PICC BSIs. These factors may inform preventive measures.

Nosocomial infections in the intensive care unit: Incidence, risk factors, outcome and associated pathogens in a public tertiary teaching hospital of Eastern India

BACKGROUND

The increased morbidity and mortality associated with nosocomial infections in the intensive care unit (ICU) is a matter of serious concern today.

AIMS

To determine the incidence of nosocomial infections acquired in the ICU, their risk factors, the causative pathogens and the outcome in a tertiary care teaching hospital.

MATERIALS AND METHODS

This was a prospective observational study conducted in a 12 bedded combined medical and surgical ICU of a medical college hospital. The study group comprised 242 patients admitted for more than 48 h in the ICU. Data were collected regarding severity of the illness, primary reason for ICU admission, presence of risk factors, presence of infection, infecting agent, length of ICU and hospital stay, and survival status and logistic regression analysis was done.

RESULTS

The nosocomial infection rate was 11.98% (95% confidence interval 7.89-16.07%). Pneumonia was the most frequently detected infection (62.07%), followed by urinary tract infections and central venous catheter associated bloodstream infections. Prior antimicrobial therapy, urinary catheterization and length of ICU stay were found to be statistically significant risk factors associated with nosocomial infection. Nosocomial infection resulted in a statistically significant increase in length of ICU and hospital stay, but not in mortality.

CONCLUSION

Nosocomial infections increase morbidity of hospitalized patients. These findings can be utilized for planning nosocomial infection surveillance program in our setting.

Laboratory-confirmed, health care-associated bloodstream infections in Jordan: a matched cost and length of stay study

BACKGROUND

No studies have been carried out in Jordan to examine length of stay (LOS) and extra cost associated with health care-associated bloodstream infections (HCABSIs). This study aims to estimate the extra LOS and cost associated with HCABSIs among adult hospitalized Jordanian patients.

METHODS

Five-year data were retrieved from 1 large university-affiliated hospital in Jordan. Matched case-control design was used in this study. Cases were determined based on confirmed positive blood culture after 48 hours of admission. Matching criteria were age (±5 years), gender, admission diagnosis, and LOS in comparison group equal to the LOS (±5%) before blood culture for the case group.

RESULTS

Of the total 445 infected patients 125 (28.1%) were matched with uninfected patients. The mean LOS after infection for cases was 12.1 days (standard deviation [SD] = 17.2) compared with 8.3 (SD = 7.9) days for the controls (P = .02). The total mean inflation-adjusted charges for cases was M (mean) = US $7,426, SD = $7,252 compared with M = $3,274, SD = $4,209 for controls, P < .001. Using multiple regression modeling, LOS after acquiring HCABSIs, admission to critical care units, and being infected with HCABSIs were significant predictors of patients' total charges.

CONCLUSION

Figures generated from this can be used to inform health care researchers, policy makers, and professionals about the impact of HCABSIs.

Healthcare-associated Staphylococcus aureus bloodstream infection: length of stay, attributable mortality, and additional direct costs

This study aimed to determine the excess length of stay, extra expenditures, and attributable mortality to healthcare-associated S. aureus bloodstream infection (BSI) at a teaching hospital in central Brazil. The study design was a matched (1:1) case-control. Cases were defined as patients >13 years old, with a healthcare-associated S. aureus BSI. Controls included patients without an S. aureus BSI, who were matched to cases by gender, age (± 7 years), morbidity, and underlying disease. Data were collected from medical records and from the Brazilian National Hospital Information System (Sistema de Informações Hospitalares do Sistema Único de Saúde - SIH/SUS). A Wilcoxon rank sum test was performed to compare length of stay and costs between cases and controls. Differences in mortality between cases and controls were compared using McNemar's tests. The Mantel-Haenzel stratified analysis was performed to compare invasive device utilization. Data analyses were conducted using Epi Info 6.0 and Statistical Package for Social Sciences (SPSS 13.0). 84 case-control pairs matched by gender, age, admission period, morbidity, and underlying disease were analyzed. The mean lengths of hospital stay were 48.3 and 16.2 days for cases and controls, respectively (p<0.01), yielding an excess hospital stay among cases of 32.1 days. The excess mortality among cases compared to controls that was attributable to S. aureus bloodstream infection was 45.2%. Cases had a higher risk of dying compared to controls (OR 7.3, 95% CI 3.1-21.1). Overall costs of hospitalization (SIH/SUS) reached US$ 123,065 for cases versus US$ 40,247 for controls (p<0.01). The cost of antimicrobial therapy was 6.7 fold higher for cases compared to controls. Healthcare-associated S. aureus BSI was associated with statistically significant increases in length of hospitalization, attributable mortality, and economic burden. Implementation of measures to minimize the risk of healthcare-associated bacterial infections is essential.

Length of stay and charges associated with health care-acquired bloodstream infections

BACKGROUND

Although many studies have examined outcomes of health care-associated bloodstream infections (HCABSIs), population-based estimates of length of stay (LOS) and costs have seldom been reported.

OBJECTIVES

Our objective was to generate US national estimates of LOS and costs associated with HCABSIs using the 2003 National Inpatient Sample (NIS).

METHODS

This study utilized a matched case-control design to estimate LOS and costs associated with HCABSIs based on the 2003 (NIS). A special set of ICD-9-CM codes was used to identify cases. A 1:1 matching procedure was used in which HCABSIs in patients were matched with uninfected patients based on age, sex, and admission diagnosis. We performed weighted analysis to construct population estimates and their standard deviations for LOS and total charges.

RESULTS

After applying the case finding criteria, 113,436 HCABSI cases were identified. The weighted mean LOS for HCABSIs cases was 16.0 days compared with 5.4 days for the control group (P < .001). The weighted mean total charges for patients with HCABSIs were $85,813 ($110,183 US in 2010) compared with $22,821 ($29,302 US in 2010) for uninfected patients (P < .001). We estimated that, in 2003, HCABSIs potentially cost the US economy nearly $29 billion ($37.24 billion US in 2010).

CONCLUSION

This study estimated the economic burden of HCABSIs on the US national economy. With some modifications, the annually published NIS data could be useful as a national surveillance tool for health care adverse events including HCABSIs.

Oral care and bacteremia risk in mechanically ventilated adults

OBJECTIVE

Transient bacteremia occurs in healthy populations from toothbrushing. With the high incidence of bacteremia in the intensive care unit and toothbrushing as an oral care method, this study examined the incidence and clinical significance of transient bacteremia from toothbrushing in mechanically ventilated adults.

METHODS

Prospective pre- and post-test with all subjects (N = 30) receiving a toothbrushing intervention twice per day (up to 48 hours). The planned microbial analysis used DNA typing to identify organisms from oral and blood cultures collected immediately before, 1 minute, and 30 minutes after the interventions.

RESULTS

Seventeen percent of subjects had oral cultures that were positive for selected pathogens before the first toothbrushing intervention. None of the subjects had evidence of transient bacteremia by positive quantitative blood cultures before or after the toothbrushing interventions. Patient characteristics were not statistically significant predictors for systemic inflammatory response syndrome, length of hospital stay, or length of intubation.

CONCLUSION

The toothbrushing intervention did not induce transient bacteremia in this patient population.

Amount of Alcohol-Based Hand Rub Used and Incidence of Hospital-Acquired Bloodstream Infection in a Danish Hospital

We investigated the association between the amount of alcohol-based hand rub (hereafter, “hand rub”) used and the incidence of healthcare-acquired bloodstream infection (HCR-BSI) from 2004 through early 2008. The amount of hand rub used increased significandy, and the incidence of HCR-BSI remained stable. There was no significant association between the amount of hand rub used and the incidence of HCR-BSI.

Risk factors for and influence of bloodstream infections on mortality: a 1-year prospective study in a Greek intensive-care unit

To determine the incidence, risk factors for, and the influence of bloodstream infections (BSIs) on mortality of patients in intensive-care units (ICUs), prospectively collected data from all patients with a stay in an ICU >48 h, during a 1-year period, were analysed. Of 572 patients, 148 developed a total of 232 BSI episodes (incidence 16·3 episodes/1000 patient-days). Gram-negative organisms with high level of resistance to antibiotics were the most frequently isolated pathogens (157 strains, 67·8%). The severity of illness on admission, as estimated by APACHE II score (OR 1·07, 95% CI 1·04–1·1, P<0·001), the presence of acute respiratory distress syndrome (OR 3·57, 95% CI 1·92–6·64, P<0·001), and a history of diabetes mellitus (OR 2·37, 95% CI 1·36–4·11, P=0·002) were risk factors for the occurrence of BSI whereas the development of an ICU-acquired BSI was an independent risk factor for death (OR 1·76, 95% CI 1·11–2·78, P=0·015). Finally, the severity of organ dysfunction on the day of the first BSI episode, as estimated by SOFA score, and the level of serum albumin, independently affected the outcome (OR 1·44, 95% CI 1·22–1·7, P<0·001 and OR 0·47, 95% CI 0·23–0·97, P=0·04 respectively).

Nosocomial infection in neonates: inevitable or preventable?

In the neonatal intensive care unit population the nosocomial infection rate is highest in the lowest-birth-weight infants. It is this group of infants who require the most therapeutic interventions to support them leading to frequent invasive procedures and the longest exposure to the hospital environment. However, infection rates vary from one unit to another, suggesting that there are differences in either how infection rates are determined or the care provided in the various units. This article will describe nosocomial infections and rates in the neonatal intensive care unit and identify strategies of care to minimize the risks of nosocomial infection in low-birth-weight infants.

Oral care and the risk of bloodstream infections in mechanically ventilated adults: A review

RATIONALE

Bacteraemia, defined as the presence of viable bacteria in the circulating blood can result in bloodstream infection, which is one of the most frequent and challenging hospital-acquired infections. Bacteraemia occurs in healthy populations with manipulation of the oral mucosa, including toothbrushing. Oral care is commonly administered to mechanically ventilated patients, it is important to determine whether this practice contributes to the incidence of bacteraemia. This paper reviews the literature on the link between the manipulation of the oral cavity and the development of bacteraemia in mechanically ventilated adults.

METHODS

Searches were conducted using Medline, CINAHL, and the Cochrane Library databases. Article inclusion criteria were (1) a focus on mechanical ventilation and critical illness, (2) human subjects, (3) adult subjects, and (4) publication in English (or available English translation).

RESULTS

Nine articles met inclusion criteria and were critiqued. All relied upon clinical data as outcome measures; many were retrospective. The three organisms most often associated with nosocomial bloodstream infections were Staphylococcus aureus, coagulase negative staphylococci, and Enterococcus species. Establishing the origin of bacteraemia was problematic in most studies.

CONCLUSIONS

Additional research is needed to understand the relationship of oral care practices to bacteraemia in mechanically ventilated adults.

Application of the sequential organ failure assessment (SOFA) score to bacteremic ICU patients

BACKGROUND

Patients admitted to intensive care units (ICUs) are at a high risk of acquiring blood stream infections. We examined whether SOFA score on ICU admission and on the day of bacteremia can predict the occurrence of bacteremia and the outcome of bacteremic ICU patients.

PATIENTS AND METHODS

All patients admitted to a multidisciplinary ICU for more than 48 h from January 1, 2002 to December 31, 2004, were prospectively studied. Demographic, clinical and laboratory data were recorded on admission for all patients and additionally, on the day of the first bacteremic episode for those patients who developed bacteremia. Accordingly, APACHE II and SOFA scores were calculated on the same day.

RESULTS

A total of 185 patients developed one or more episodes of bacteremia, giving an incidence of 9.6 per 1,000 ICU days. The ICU mortality rate was 43.9% for bacteremic and 25.8% for the remaining patients (p < 0.001). Admission SOFA score was independently associated with the occurrence of bacteremia (OR = 1.20, 95% CI: 1.11-1.26, p < 0.001). Among bacteremic patients, SOFA score on the day of bacteremia was the only independent prognostic factor for outcome (OR = 1.44, 95% CI: 1.21-1.71, p < 0.001). When all patients were included in the multivariate analysis, admission SOFA (OR = 1.3, CI: 1.16-1.38, p < 0.001), APACHE II (OR = 1.1, CI: 1.02-1.11, p = 0.003) score and the presence of bacteremia (OR = 1.8, CI: 1.1-2.9, p = 0.023) were independently associated with the outcome.

CONCLUSION

Admission SOFA score is independently associated with the occurrence of ICU-acquired bacteremia, whereas it is not sufficient to predict the outcome of patients who subsequently will develop this complication. However, SOFA score on the first day of bacteremia is an independent prognostic factor for outcome in these patients.

Effect of an immune-enhancing diet on lymphocyte in head-injured rats: What is the role of arginine?

OBJECTIVE

The benefit of immune-enhancing diets (IEDs) in the intensive care unit remains controversial. Considering their complexity, the role of each component, in particular arginine (Arg), in their properties is largely unknown. The aim of this study was to determine the role of arginine in the immunomodulatory effects of an IED (Crucial) in head-injured rats.

DESIGN

Thirty-four rats were randomized into five groups: AL (ad libitum), HI (head-injured), HI-STD (HI + standard enteral nutrition, EN), HI-STD-Arg (HI + standard EN + Arg in equimolar concentration to Arg in IED), and HI-IED (HI + IED). These isocaloric and isonitrogenous diets were administered over 4 days. After death, the thymus was removed and weighed. The density of CD25, CD4 and CD8 on lymphocytes from blood and from Peyer patches was evaluated. Mesenteric lymph nodes, liver and spleen were cultured for analysis of enterobacterial translocation and dissemination.

MEASUREMENTS AND RESULTS

HI induced an atrophy of the thymus which was not corrected by the standard diet (HI 0.27 +/- 0.03, HI-STD 0.35 +/- 0.03 vs. AL 0.49 +/- 0.02 g; p < 0.05). However, the standard diet supplemented with arginine limited the thymic atrophy and the IED restored thymus weight. CD25 density and interleukin-2 production were increased only in the HI-STD-Arg and HI-IED groups (p < 0.05). Head injury induced enterobacterial translocation and dissemination which were blunted only in the HI-STD-Arg group (p < 0.05).

CONCLUSIONS

In this rat HI model, arginine appears to be safe, contributes to a large extent to the immunomodulatory effects of the IED, and seems to limit enterobacterial translocation and dissemination more efficiently alone than in an IED.

[Nosocomial infections in the intensive care unit of a gynecology clinic]

INTRODUCTION

Nosocomial infections are caused by microorganisms, and they develop 48 hours or more after admission to a hospital. It is considered that these infections are neither manifested nor present during the incubation period at the time of admission.

MATERIAL AND METHODS

The objective of our study was to identify the most frequent microorganisms causing nosocomial infections in the Intensive Care Unit of the Institute of Gynecology and Obstetrics. The study included 33 patients, mean age 43.5 +/- 5 years, who were critical cases treated in Intensive Care Unit of the Institute of Gynecology and Obstetrics, Clinical Center of Serbia, in the period 2001 - 2003. All patients were surgically treated, intubated and assisted by mechanical ventilation.

RESULTS

The most common causative agents isolated from the endotracheal tube were Staphylococcus aureus, Staphylococcus coagulasa negative and Pseudomonas spp., whereas Escherichia colli and Enterococcus were isolated from the wounds. These are highly resistant strains to antimicrobial agents.

DISCUSSION

Two big groups of microorganisms were isolated as causative organisms of nosocomial infections. The first group causes blood stream infections, such as Staphilococcus aureus and coagulasa negative, and the second group causes respiratory infections like Pseudomonas aeruginosa, Klebsiella Enterobacter and Acinetobacter. The mortality and morbidity are very high, up to 40 - 80%.

CONCLUSION

We can conclude that invasive diagnostic procedures are causing a high percentage of nosocomial infections. It is of utmost importance to prevent these infections by early use of antibiotics and infection control which depends on the hospital or clinic.

Microscale correlation between surface chemistry, texture, and the adhesive strength of Staphylococcus epidermidis

Staphylococcus epidermidis is among the most commonly isolated microbes from medical implant infections, particularly in the colonization of blood-contacting devices. We explored the relationships between surface wettability and root-mean-square roughness (Rq) on microbial adhesive strength to a substrate. Molecular-level interactions between S. epidermidis and a variety of chemically and texturally distinct model substrata were characterized using a cellular probe and atomic force microscopy (AFM). Substrata included gold, aliphatic and aromatic self-assembled monolayers, and polymeric and proteinaceous materials. Substrate hydrophobicity, described in terms of the water contact angle, was an insufficient parameter to explain the adhesive force of the bacterium for any of the surfaces. Correlations between adhesion forces and Rq showed weak relationships for most surfaces. We used an alternate methodology to characterize the texture of the surface that is based on a fractal tiling algorithm applied to images of each surface. The relative area as a function of the scale of observation was calculated. The discrete bonding model (DBM) was applied, which describes the area available for bonding interactions over the full range of observational scales contained in the measured substrate texture. Weak negative correlations were obtained between the adhesion forces and the area available for interaction, suggesting that increased roughness decreases bacterial adhesion when nano- to micrometer scales are considered. We suggest that modification of the DBM is needed in order to include discontinuous bonding. The adhesive strength is still related to the area available for bonding on a particular scale, but on some very fine scales, the bacteria may not be able to conform to the valleys or pits of the substrate. Therefore, the bonding between the bacterium and substrate becomes discontinuous, occurring only on the tops of ridges or asperities.

Increased mortality among elderly patients with meticillin-resistant Staphylococcus aureus bacteraemia

Despite the high prevalence of meticillin-resistant Staphylococcus aureus (MRSA) infections among the elderly, outcomes of nosocomial MRSA bloodstream infections (BSI) for this patient population have not been fully examined. We performed a case-control study to compare outcomes of hospital-acquired MRSA BSI among patients >/=65 years of age (cases) with those younger than 65 years of age (controls). In a 430-bed tertiary-care teaching hospital, 100 hospitalized patients >/=18 years of age with S. aureus BSI were included in the study. Measurements obtained were: comorbidities, severity of illness at presentation, antibiotic therapy, haematogenous complications and mortality. Overall mortality was significantly higher among cases than controls [36% vs 12%; odds ratio (OR) 4.1, 95% confidence interval (CI) 1.4-14, P<0.01]. A pulmonary source was identified more frequently among elderly patients compared with younger controls (34% vs 16%; OR 2.7, 95%CI 1.1-8.1, P=0.04). On logistic regression, the following variables were independently associated with MRSA BSI among elderly patients: admission to a medical ward (OR 3.1, 95%CI 1.3-7.6, P=0.02), non-central-venous-catheter-related BSI (OR 3, 95%CI 1.2-7.6, P=0.02) and death (OR 3.7, 95%CI 1.3-11, P=0.02). Among patients who received vancomycin, more cases were treated with a reduced dose of vancomycin due to renal insufficiency compared with controls (64% vs 31%; OR 4, 95%CI 2-9, P=0.01). These data suggest that MRSA BSI is associated with significant mortality among the elderly population. Preventing MRSA acquisition among this patient population is of paramount importance.

Genotypic analysis of Acinetobacter bloodstream infection isolates in a Turkish university hospital

Acinetobacter baumannii is a significant pathogen of bloodstream infections in hospital patients that frequently causes single clone outbreaks. We aimed to evaluate the genetic relatedness and antimicrobial susceptibility of Acinetobacter spp. bloodstream isolates, in order to obtain insight into their cross-transmission. This prospective study was conducted at the Erciyes University Hospital. During a 1-y period, all patients with nosocomial BSI caused by Acinetobacter spp. were included in the study. All data with regard to the patients, underlying diseases and risk factors for BSI and the severity of disease were collected. Blood culture isolates of Acinetobacter spp. were identified according to their morphology and biochemical reactions. The antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion test according to the NCCLS; the genetic relatedness of isolates was determined by RAPD-PCR analysis and pulsed-field gel electrophoresis (PFGE). 41 patients acquired a nosocomial bloodstream infection caused by A. baumanii during this period. 88% of these infections (36 of 41) occurred while the patients were treated in the intensive care unit. Nearly 80% of the isolates belonged to 3 genotypes, suggesting cross-transmission in ICU settings where infection control practices are poor. All Acinetobacter isolates were multidrug-resistant and the crude mortality of patients infected with A. baumanii was 80.5%. We concluded that the genetic relatedness of Acinetobacter spp. causing BSI was very high, indicating cross-transmission within the ICU setting. Essential components of an infection control programme to prevent nosocomial transmission of A. baumannii are early detection of colonized patients, followed by strict attention to standard precautions and contact isolation.

Prospective surveillance of phlebitis associated with peripheral intravenous catheters

BACKGROUND

Guidelines have been published for prevention of phlebitis associated with peripheral intravenous catheters (IVC), but this complication continues to occur. We sought to determine the rate of phlebitis associated with peripheral IVCs to identify predictors for phlebitis and to isolate pathogenic bacteria from phlebitic catheter tips.

METHODS

Nine-point prevalence studies were conducted during the years 1996-2003 of all hospitalized patients with a peripheral IVC. During the last 3 surveys, conducted in 2003, phlebitic lines were removed, and, for each line, 1 to 2 nonphlebitic lines, in place for 48 to 72 hours, were removed and cultured as controls. In between these surveys, findings and guidelines for improvement were distributed to the staff.

RESULTS

During these surveys, 40% +/- 8% of hospitalized patients had a peripheral IVC. The rate of peripheral IVC-associated phlebitis decreased from 12.7% (20/157) in 1998 to 2.6% (5/189) in 2003 (P < .01). Factors significantly associated with phlebitis included pain (P < .001), presence of the catheter for longer than 3 days (P < .05), and cleanliness of the dressing (P < .01).

CONCLUSION

The rate of phlebitis associated with peripheral intravenous catheters decreased significantly throughout the study period. The identification of predictors for phlebitis and the dissemination of this information in an educational drive may have contributed to this improvement.

Nosocomial infections in the intensive care units

Background/Aim. The risk for nosocomial infections (NIs) is 5-10 times higher in patients hospitalized in the Intensive Care Units (ICUs) than in patients staying in other wards. The higher incidence rates of NIs in the ICUs may be explained by the fact that the patients in the ICUs have more severe underlying disease, and are exposed to the invasive diagnostic and therapeutical procedures. The unreasonable use of antibiotics leads to the selection of multiresistant agents, which have been increasingly recorded as the NIs causative agents. The aim of this study was to investigate the characteristics of NIs in the ICUs in the period January-June 2005. Methods. The study of incidence was performed in accordance with the methodology of the Centers for Diseases and Prevention. Any infections in the patients hospitalized in the ICUs in the period from January to June 2005 were registered. The results both from medical documentation and from the direct contacts with the medical personnel were analyzed. The samples were tested using standard methods in the microbiological laboratory. Results. The incidence rates of NIs patients ranged from 1.5 to 40.8, and the incidence rates of infections were 1.5 to 65.6 per 1 000 patient?s days. Out of the total number of NIs, urinary infections accounted for 44.6%, blood infections for 37.6%, and surgical site infections for 16.9%. Conclusion. The most frequent cause of nosocomial urinary infections was Klebsiella, of nosocomial sepsis - coagulase ? negative staphylococci, and of surgical site infections - Staphylococcus aureus.

Epidemiological characteristics of nosocomial bloodstream infections and their causes

Background/Aim. Nosocomial bloodstream infections (BSI) contribute to grater morbidity and mortality rates, as well as to increasing length of hospital stay and health care costs. All patients with nosocomial BSI identified during the one-year period were studied to identify microbiological factors associated with these infections. Methods. A one-year prospective cohort study was performed in patients in intensive care units (ICU), and non- ICU patients. The patients were identified by active surveillance and positive blood cultures during the study period. The definitions of nosocomial BSI of the Center for Diseases Control and Prevention, Atlanta were used. Hospital laboratory detected growth in blood cultures, identified organisms, and performed susceptibility testing were in according with the American National Committee for Clinical Laboratory Standards. Results. The incidence of nosocomial BSI was 2.2 per 1 000 admission in non-ICU and 17.4 per 1 000 admission in ICU patients. The 28- day crude mortality rate was 44.9%. There were 60.3% primary nosocomial BSI. Gram-negative organisms accounted for 50%, gram-positive organisms accounted for 44.9%, and 4.1% were caused by fungi. The most common pathogens were coagulasenegative staphylococci (21.4%), Staphylococcus aureus (14.3%), Klebsiella spp. (13.3%), Pseudomonas aeruginosa (8.2%), Acinetobacter spp. (7.1%). Methicillin resistance was detected in 64.3% of S.aureus and 100% of coagulasa-negative staphylococci. Vancomycin resistance in enterococci and staphylococci was not deteced. The proportion of ceftazidim resistance among K.pneumoniae isolates was 92%. Conclusion. This study might help to better understanding not only the characteristics of BSI, but also the featares of their causes, primarily the resistance of coagulase-negative staphylococci and S. aureus to methicillin, and of K. pneumoniae to ceftazidime.

Risk factors for hospital-acquired bacteremia

OBJECTIVE

Bacteremia is one of the most serious health problems associated with high morbidity and mortality. The aim of this study was to identify risk factors for bacteremia in daily medical care to facilitate rapid and accurate clinical decisions about treatment.

PATIENTS AND METHODS

We studied 306 inpatients retrospectively. Age, peripheral neutrophil count, C-reactive protein (CRP), platelets, serum total cholesterol, total protein, albumin and cholinesterase were compared in patients with positive- and negative-blood cultures. The associations between blood culture positivity and glucose tolerance, bedridden state, presence of a central venous catheter (CVC) or urinary catheter were examined. On October 14, 2002, strategies for prevention of catheter-related infection were altered in our hospital. We studied the impact of these changes on the risk of bacteremia.

RESULTS

Sixty-seven patients had positive and 239 had negative blood cultures. Age, neutrophil, platelets, total protein, albumin, and cholinesterase were significantly different between the culture-positive patients and the culture-negative patients. Multivariate analysis showed albumin and platelets as independent predictors. The bedridden state and catheter-inserted states (central venous or urinary) conferred significantly higher positive blood culture rates. Multivariate analysis showed using urinary catheters and indwelling femoral CVCs as independent risk factors. There was no significant difference in the blood culture-positive rate before and after the change in prevention strategies; before the change, 6 of 9 catheter-inserted blood culture-positive cases yielded MRSA, while 4 of 12 cultures yielded Staphylococcus epidermidis after the change.

CONCLUSION

Our study highlights the risk factors of bacteremia in vulnerable patients.

A randomized, prospective clinical trial to assess the potential infection risk associated with the PosiFlow needleless connector

The microbial contamination rate of luers of central venous catheters (CVCs) with either PosiFlow needleless connectors or standard caps attached was investigated. The efficacy of 70% (v/v) isopropyl alcohol, 0.5% (w/v) chlorhexidine in gluconate 70% (v/v) isopropyl alcohol and 10% (w/v) aqueous povidone-iodine to disinfect the intravenous connections was also assessed. Seventy-seven patients undergoing cardiac surgery who required a CVC as part of their clinical management were randomly allocated either needleless connectors or standard caps. Patients were also designated to receive chlorhexidine/alcohol, isopropyl alcohol or povidone-iodine for pre-CVC insertion skin preparation and disinfection of the connections. After 72 h in situ the microbial contamination rate of 580 luers, 306 with standard caps and 274 with needleless connectors attached, was determined. The microbial contamination rate of the external compression seals of 274 needleless connectors was also assessed to compare the efficacy of the three disinfectants. The internal surfaces of 55 out of 306 (18%) luers with standard caps were contaminated with micro-organisms, whilst only 18 out of 274 (6.6%) luers with needleless connectors were contaminated (P<0.0001). Of those needleless connectors disinfected with isopropyl alcohol, 69.2% were externally contaminated with micro-organisms compared with 30.8% disinfected with chlorhexidine/alcohol (P<0.0001) and 41.6% with povidone-iodine (P<0.0001). These results suggest that the use of needleless connectors may reduce the microbial contamination rate of CVC luers compared with the standard cap. Furthermore, disinfection of needleless connectors with either chlorhexidine/alcohol or povidone-iodine significantly reduced external microbial contamination. Both these strategies may reduce the risk of catheter-related infections acquired via the intraluminal route.

Source of infection and other factors associated with case fatality in community-acquired bacteremia—a Danish population-based cohort study from 1992 to 1997

OBJECTIVE

To examine the association between the source of infection, other factors and the 30-day case-fatality rate (CFR) in patients with community-acquired bacteremia.

METHODS

We included in the study 1844 patients older than 15 years (median age 72 years) with a first episode of community-acquired bacteremia in the period 1992-97 from a population-based bacteremia database. Information on co-morbidity, antibiotic prescriptions and date of death was obtained from health registries through linkage with the patient's personal identification number. The outcome measure was the overall CFR.

RESULTS

The mean CFR was 18% (20% in 1992-95, 15% in 1996-97). The commonest sources of infection were the urinary tract (29%) and the respiratory tract (20%); patients with an undetermined source accounted for 21% in 1992-95 and 13% in 1996-97. The most frequent bacteria were Escherichia coli (33%) and Streptococcus pneumoniae (22%). Thirty-two per cent of patients did not receive appropriate empirical antibiotic therapy. The following factors were associated with CFR: source of infection other than the urinary tract, first four years of the study, age >/=75 years, and presence of co-morbidity. An undetermined source showed the strongest association with CFR during the period 1996-97.

CONCLUSIONS

As an undetermined source of infection was strongly associated with CFR, physicians should be aware of the significance of identifying and eliminating a source of infection, and more efforts should be directed at timely and appropriate empirical antibiotic therapy.

Nosocomial infections in adult intensive-care units

Nosocomial infections affect about 30% of patients in intensive-care units and are associated with substantial morbidity and mortality. Several risk factors have been identified, including the use of catheters and other invasive equipment, and certain groups of patients-eg, those with trauma or burns-are recognised as being more susceptible to nosocomial infection than others. Awareness of these factors and adherence to simple preventive measures, such as adequate hand hygiene, can limit the burden of disease. Management of nosocomial infection relies on adequate and appropriate antibiotic therapy, which should be selected after discussion with infectious-disease specialists and adapted as microbiological data become available.

Device-related sources of bacteraemia in English hospitals--opportunities for the prevention of hospital-acquired bacteraemia

Between 1997 and 2001, 17 teaching and 56 non-teaching acute English hospitals conducted hospital-wide surveillance of hospital-acquired bacteraemia (HAB) using a standard protocol drawn up by the Nosocomial Infection National Surveillance Scheme (NINSS). The sources of organisms, the incidence of device-related HAB, and the distribution of HABs from individual device-related sources by specialty and type of hospital were determined for 6,956 HABs in order to identify where resources should best be targeted to reduce these infections. The overall incidence of HAB was higher in teaching than in non-teaching hospitals: 5.39 and 2.83 HABs per 1,000 patients at risk, respectively (P<0.001). Device-related sources were responsible for 52.4 and 43.2% of all HABs in teaching and non-teaching hospitals, respectively (P<0.001), and central lines were the commonest source, causing 38.3% of HABs in teaching versus 22.3% in non-teaching hospitals (P<0.001). In teaching hospitals, general intensive care units (ICUs), haematology, special care baby units (SCBUs), nephrology, and oncology accounted for only 6.1% of the population surveyed, but had the highest incidence of HAB, and contributed 47.8% of 2091 HABs and 56.9% of 1,095 device-related bacteraemias. Of 623 device-related bacteraemias in these high-risk specialties, 554 (88.9%) were from central lines. Thus, in teaching hospitals, resources should be targeted primarily at the prevention of central line-related bacteraemia in these five high-risk specialties, and the surveillance should include data on central line use. In non-teaching hospitals, nearly two thirds (63.3%) of 4,865 HABs and 60.7% of 2,103 device-related bacteraemias were from a few specialties with a low incidence of bacteraemia, but large numbers of patients, namely general medicine, general surgery, geriatric medicine and urology. These specialties accounted for 50.5% of the population surveyed. Central lines were the most common source of bacteraemia in general medicine and surgery, and together accounted for 23.3% of all device-related bacteraemias. However, in geriatric medicine and urology, central line sources were infrequent, accounting for only 1.7% of all device-related bacteraemias. On the other hand, bacteraemia from catheter-associated UTI were common in all these four specialties accounting for 20.9% of all device-related bacteraemias. Thus, in non-teaching hospitals, resources should be targeted primarily at these low-risk specialties and surveillance should include, at least, bacteraemia from central lines and from catheter-associated UTI. Further benefit can be obtained by including central line-related bacteraemias from general ICU and haematology patients, as they contributed 17.0% of all device-related bacteraemias in non-teaching hospitals.

Nosocomial bloodstream infections in Finnish hospitals during 1999-2000

Prospective laboratory-based surveillance in 4 Finnish hospitals during 1999-2000 identified 1477 cases of nosocomial bloodstream infection (BSI), with an overall rate of 0.8 BSIs per 1000 patient-days. Of BSI cases, 33% were in patients with a hematological malignancy and 15% were in patients with a solid malignancy; 26% were in patients who had undergone surgery preceding infection. Twenty-six percent of BSIs were related to intensive care, and 61% occurred in patients with a central venous catheter. Sixty-five percent of the 1621 causative organisms were gram positive, 31% were gram negative, and 4% were fungi. The most common pathogens were coagulase-negative staphylococci (31%), Escherichia coli (11%), Staphylococcus aureus (11%), and enterococci (6%). Methicillin resistance was detected in 1% of S. aureus isolates and vancomycin resistance in 1% of enterococci. The 7-day case-fatality ratio was 9% and was highest for infections caused by Candida (21%) and enterococci (18%). The overall rate of nosocomial BSIs was similar to rates in England and the United States, but S. aureus, enterococci, and fungi were less common in our study, and the prevalence of antibiotic resistance was lower.

Minimizing the workup of blood culture contaminants: implementation and evaluation of a laboratory-based algorithm

An algorithm was implemented in the clinical microbiology laboratory to assess the clinical significance of organisms that are often considered contaminants (coagulase-negative staphylococci, aerobic and anaerobic diphtheroids, Micrococcus spp., Bacillus spp., and viridans group streptococci) when isolated from blood cultures. From 25 August 1999 through 30 April 2000, 12,374 blood cultures were submitted to the University of Iowa Clinical Microbiology Laboratory. Potential contaminants were recovered from 495 of 1,040 positive blood cultures. If one or more additional blood cultures were obtained within +/-48 h and all were negative, the isolate was considered a contaminant. Antimicrobial susceptibility testing (AST) of these probable contaminants was not performed unless requested. If no additional blood cultures were submitted or there were additional positive blood cultures (within +/-48 h), a pathology resident gathered patient clinical information and made a judgment regarding the isolate's significance. To evaluate the accuracy of these algorithm-based assignments, a nurse epidemiologist in approximately 60% of the cases performed a retrospective chart review. Agreement between the findings of the retrospective chart review and the automatic classification of the isolates with additional negative blood cultures as probable contaminants occurred among 85.8% of 225 isolates. In response to physician requests, AST had been performed on 15 of the 32 isolates with additional negative cultures considered significant by retrospective chart review. Agreement of pathology resident assignment with the retrospective chart review occurred among 74.6% of 71 isolates. The laboratory-based algorithm provided an acceptably accurate means for assessing the clinical significance of potential contaminants recovered from blood cultures.