Surveillance of nosocomial infections: a fundamental ingredient for quality

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.

Impact of availability of guidelines and active surveillance in reducing the incidence of ventilator-associated pneumonia in Europe and worldwide

BACKGROUND

To analyse whether the availability of written standards for management of mechanically ventilated patients and/or the existence of a surveillance system for cases of ventilation-associated pneumonia (VAP) are positively associated with compliance with 6 well-established VAP prevention measures.

METHODS

Ecological study based on responses to an online-questionnaire completed by 1730 critical care physicians. Replies were received from 77 different countries, of which the majority, i.e. 1351, came from 36 European countries.

RESULTS

On a cross-country level, compliance with VAP prevention measures is higher in countries with a large number of prevention standards and/or VAP surveillance systems in place at ICU level., Likewise, implementation of standards and VAP surveillance systems has a significant impact on self-reported total compliance with VAP prevention measures (both p < 0.001). Moreover, predictions of overall prevention measure compliance show the effect size of the availability of written standards and existence of surveillance system. For instance, a female physician with 10 years of experience in critical care working in a 15-bed ICU in France has a predicted baseline level of VAP prevention measure compliance of 63 per cent. This baseline level increases by 9.5 percentage points (p < 0.001) if a written clinical VAP prevention standard is available in the ICU, and by another 4 percentage points (p < 0.001) if complemented by a VAP surveillance system.

CONCLUSIONS

The existence of written standards for management of mechanically ventilated patients in an ICU and the availability of VAP surveillance systems have shown to be positively associated with compliance with VAP prevention measures and should be fostered on a policy level.

Correlation of risk and postoperative assessment methods in wound surveillance

BACKGROUND

Various surveillance methods have been described for surveillance of surgical site infections (SSI). The aim of this study was to examine practicality of SSI risk assessment methods (Study on the Efficacy of Nosocomial Infection Control [SENIC] and National Nosocomial Infections Surveillance [NNIS]) with a postoperative wound monitoring scale (ASEPSIS) as an outcome assessment measure.

MATERIALS AND METHODS

Patients were followed with a prospective data chart from January 1, 2003, to December 31, 2005. Correlation of SENIC and NNIS together with ASEPSIS were performed.

RESULTS

During the study period, 222 SSI occurred. SSIs were determined within the 21-d period after operations. Correlation between SENIC with ASEPSIS (r(s) = 0.47, P < 0.001) was found better than that for NNIS with ASEPSIS (r(s) = 0.41, P < 0.001). Type of operation (emergency versus elective), body mass index, operation class, and American Society of Anesthesiologists scores were found independently predictive factors for SSI.

CONCLUSIONS

This study indicates weak but significant correlation between preoperative risk assessment methods for SSI and ASEPSIS.

Administrative coding data, compared with CDC/NHSN criteria, are poor indicators of health care-associated infections

BACKGROUND

ICD-9-CM coding alone has been proposed as a method of surveillance for health care-associated infections (HAIs). The accuracy of this method, however, relative to accepted infection control criteria is not known.

METHODS

Retrospective analysis of patients at an academic medical center in 2005 who underwent surgical procedures or who were at risk for catheter-associated bloodstream infections or ventilator-associated pneumonia was performed. Patients previously identified with HAIs by Centers for Disease Control and Prevention's National Healthcare Safety Network surveillance methods were compared with those of the same risk group identified by secondary infection ICD-9-CM codes. Discordant cases identified by only coding were all rereviewed and adjusted prior to final analysis. When coding and surveillance were both negative, a sample of patients was used to estimate the proportion of false negatives in this group.

RESULTS

The positive predictive values (PPVs) ranged from 0.14 to 0.51 with an aggregate of 0.23, even after adjustment for additional cases detected on subsequent medical record review. The negative predictive values (NPVs) ranged from 0.91 to 1.00, with an aggregate of 0.96. The estimates of the true variance of PPVs and NPVs across surgical procedures were small (0.0129, standard error, 0.009; 0.000145, standard error, 0.00019, respectively) and could be mostly explained by variation in prevalence of surgical site infections.

CONCLUSION

Administrative coding alone appears to be a poor tool to be used as an infection control surveillance method. Its proposed use for routine HAI surveillance, public reporting of HAIs, interfacility comparisons, and nonpayment for performance should be seriously questioned.

[Hospital infections in the maternity department at Brest Hospital over a period from 2000 to 2005]

Hospital infections are at stake in terms of public health. They are responsible for increase in morbidity and involve the community in high costs. Epidemiologic surveillance has been initiated in the departments of gynecology, obstetrics and maternity with a view to making out the rate of hospital-acquired infections and the risk factors associated to them. It is an incidence survey over a period from 2000 to 2005. Surveillance slips are filled in for every childbirth. All suspicions of hospital infections are analysed in morbidity reviews every trimester. A request to the Medical Information Department of the hospital has allowed to look for variables which were not mentioned on the initial questionnaire and so carry out a more complete analysis. The number of hospital infections amounts to 118 over 9526 childbirths, corresponding to an incidence rate of 1.24%. After vaginal delivery the encountered risk factors are: episiotomy or perineal trauma, epidural anesthesia, urinary infection and the use of tools. After a caesarean section the risk factors are: general anesthesia and lack of antibioprophylaxy. The rate of hospital infections in the maternity department at Brest's centre hospitalier universitaire (CHU) during the considered period and the observed tendency to a decreasing of hospital infections over the same period apparently denotes the interest of surveillance in matter of hospital infections in maternity.

Local Dimensionality Reduction and Supervised Learning Within Natural Clusters for Biomedical Data Analysis

Inductive learning systems were successfully applied in a number of medical domains. Nevertheless, the effective use of these systems often requires data preprocessing before applying a learning algorithm. This is especially important for multidimensional heterogeneous data presented by a large number of features of different types. Dimensionality reduction (DR) is one commonly applied approach. The goal of this paper is to study the impact of natural clustering--clustering according to expert domain knowledge--on DR for supervised learning (SL) in the area of antibiotic resistance. We compare several data-mining strategies that apply DR by means of feature extraction or feature selection with subsequent SL on microbiological data. The results of our study show that local DR within natural clusters may result in better representation for SL in comparison with the global DR on the whole data.

Surgical site infection - a European perspective of incidence and economic burden

This retrospective review of reported surgical site infection (SSI) rates in Europe was undertaken to obtain an estimated scale of the problem and the associated economic burden. Preliminary literature searches revealed incomplete datasets when applying the National Nosocomial Infection Surveillance System criteria. Following an expanded literature search, studies were selected according to the number of parameters reported, from those identified as critical for accurate determination of SSI rates. Forty-eight studies were analysed. None of the reviewed studies recorded all the data necessary to enable a comparative assessment of the SSI rate to be undertaken. The estimated range from selected studies analysed varied widely from 1.5-20% - a consequence of inconsistencies in data collection methods, surveillance criteria and wide variations in the surgical procedures investigated - often unspecified. SSIs contribute greatly to the economic costs of surgical procedures - estimated range: 1.47-19.1 billion Euro dollars. The analysis suggests that the true rate of SSIs, currently unknown, is likely to have been previously under-reported. Consequently, the associated economic burden is also likely to be underestimated. A significant improvement in study design, data collection, analysis and reporting will be necessary to ensure that SSI baseline rates are more accurately assessed to enable the evaluation of future cost-effective measures.

Assessing the status of infection control programs in small rural hospitals in the western United States

BACKGROUND

Organized infection control (IC) interventions have been successful in reducing the acquisition of hospital-associated infections. Rural community hospitals, although contributing significantly to the US health care system, have rarely been assessed regarding the nature and quality of their IC programs.

METHODS

A sample of 77 small rural hospitals in Idaho, Nevada, Utah, and eastern Washington completed a written survey in 2000 regarding IC staffing, infrastructure support, surveillance of nosocomial infections, and IC policies and practices.

RESULTS

Almost all hospitals (65 of 67, 97%) had one infection control practitioner (ICP), and 29 of 61 hospitals (47.5%) reported a designated physician with IC oversight. Most ICPs (62 of 64, 96.9%) were also employed for other activities outside of IC. The median number of ICP hours per week for IC activities was 10 (1-40), equating to a median of 1.56 (0.30-21.9) full-time ICPs per 250 hospital beds. Most hospitals performed total house surveillance for nosocomial infections (66 of 73, 90.4%) utilizing Centers for Disease Control and Prevention (CDC) definitions (69 of 74, 93.2%). Most also monitored employee bloodborne exposures (69 of 73, 94.5%). All hospitals had a written bloodborne pathogen exposure plan and isolation policies. CDC guidelines were typically followed when developing IC policies. Access to medical literature and online resources appeared to be limited for many ICPs.

CONCLUSIONS

Most rural hospitals surveyed have expended reasonable resources to develop IC programs that are patterned after those seen in larger hospitals and conform to recommendations of consensus expert panels. Given these hospitals' small patient census, short length of stay, and low infection rates, further studies are needed to evaluate necessary components of effective IC programs in these settings that efficiently utilize limited resources without compromising patient care.

Implementing and evaluating a rotating surveillance system and infection control guidelines in 4 intensive care units

BACKGROUND

In clinical practice, scientific evidence about infection control is often ignored and hygiene rituals are followed.

METHODS

Within an evidence-based infection control program, a quarterly rotating surveillance program for nosocomial infections was implemented in 4 intensive care units (ICUs) at the Aachen University Hospital, Germany.

RESULTS

For the first time, the unit-specific nosocomial infection situation was made clear to the clinical staff by interpretive feedback of the surveillance data. This led to an increased awareness of infection control and a critical review of hygiene practices. After the first surveillance period, the hygiene practices of each ICU were revised and modified. The Centers for Disease Control and Prevention/Hospital Infection Control Practices Advisory Committee guidelines for the prevention of nosocomial infections were adopted and established in tight collaboration with the ward staff.

CONCLUSIONS

Within the surveillance process, communication and team spirit between infection control and patient care personnel showed a remarkable improvement. Awareness and compliance with hospital hygiene and infection control practices could be raised without directive interaction.

Automated entry of nosocomial infection surveillance data: use of an optical scanning system

Surveillance of nosocomial infections is the foundation of any infection control programme. One of the main obstacles to surveillance is the speed and accuracy of data collection and entry. To overcome this bottleneck, we instituted automated data capture and processing in a number of point-prevalence and continuous nosocomial infection surveillance programmes. The system incorporated a document scanner, form design and processing software (Formic for Windows version 2) and statistical analysis software SPSS (Statistical Products and Service Solutions). After designing the surveillance questionnaire, it was completed by putting an X or a numeral in the the appropriate boxes. Information was collected by the infection control nurse and/or by members of clinical staff depending on the type of surveillance being undertaken. Once the form was completed it was returned and scanned using a document scanner with automatic feed. The software read and evaluated the data on each page. Data from 16741 A4 sides of surveillance questionnaires were automatically processed in a total time of 37.3 hours. This system was found to have a 99.98% accuracy rate and it was estimated to be 22 times quicker than manual entry of data. Infection control teams who are required to carry out surveillance activities should consider automatic data-entry systems. The versatility of such systems makes it possible to achieve extensive surveillance with limited resources.

Nosocomial infections in the intensive care units at a university hospital in a developing country: comparison with National Nosocomial Infections Surveillance intensive care unit rates

OBJECTIVE

As a measure of the quality of care provided to patients in the intensive care unit, comparison of nosocomial infection rates with those of the National Nosocomial Infection surveillance was completed during a 3-year observation period.

DESIGN

The study design was a prospective study during 3 years between 1993 and 1995. During that period, patients at the medical/surgical and neurosurgical intensive care units and the high-risk nursery were surveyed for nosocomial infections. Device use, bloodstream infection, urinary tract infection, and ventilator-associated pneumonia nosocomial infection rates were calculated and compared with the National Nosocomial Infection Surveillance published rates for the same period.

SETTING

The study setting was the medical/surgical intensive care unit, the neurosurgical intensive care unit, and the high-risk nursery at the Jordan University Hospital.

RESULTS

Overall infection rates were 17.2 per 100 patients in the medical/surgical intensive care unit, 14.2 to 18.5 per 100 patients in the neurosurgical intensive care unit, and 13.4 to 73.5 per 100 patients in the high-risk nursery. When compared with the weight of the infants, these rates were 61.9 to 94 per 100 in infants weighing <1500 g, 26 to 30.8 per 100 patients in infants weighing >1500 g to 2500 g, and 11.7 to 14.4 per 100 in infants weighing >2500 g. Whereas device use was moderate, bloodstream infection and ventilator-associated pneumonia rates were >90th percentile for National Nosocomial Infection Surveillance in the high-risk nursery, and urinary tract infection was >90th percentile in the medical/surgical and neurosurgical intensive care units. Nosocomial infections at the intensive care units in developing countries need further investigation and control.

Methodologies used in surveillance of surgical wound infections and bacteremia in Australian hospitals

BACKGROUND

The prevalence of nosocomial infection in Australian hospitals is estimated to be between 5.5% and 6.3%. Since 1989, infection control professionals (ICPs) in hospitals accredited by the Australian Council on Health Care Standards (ACHS) have been encouraged to collect nosocomial infection data according to ACHS methodology.

METHOD

In 1996, we surveyed members of the Australian Infection Control Association to examine the time spent on surveillance, the practice of surveillance of all hospital infections (hospital-wide surveillance), case-finding methods, case definitions, and reporting routinely used by ICPs in acute care hospitals. We also examined the ICPs' education and experience in infection control (IC).

RESULTS

The survey was completed and returned by 65% (644 of 993) of Australian Infection Control Association members. Of the ICPs who completed the survey, 47.8% (308 of 644; 95% CI, 43.9%-51.7%) met the criteria for inclusion, because they coordinated an IC program in an acute care or surgical hospital and performed surveillance for either surgical wound infection, intravascular device-related bacteremia, or non-device-related bacteremia. Of the ICPs who reported their facility's accreditation status, 93.5% participated in ACHS system. Most (97.6%) ICPs had completed hospital-based general registered nurse training. Only 1.9% (6 of 308) of ICPs reported completion of continuing education relating to hospital epidemiology. The number of years of IC experience ranged from zero to 35 years, with a median of 4 years. ICPs spent a substantial proportion of their total weekly IC time on surveillance irrespective of ACHS accreditation; 19.5 hours in ACHS hospitals and 15.6 hours in non-ACHS hospitals (P =.33). More than three quarters (76.0%) of ICPs performed hospital-wide surveillance. The case-finding methods, definitions of infections, and reporting formats varied greatly. The definition most commonly applied by ICPs (6.8%; 95% CI, 4.1%-10.4%) to define surgical wound infection was infection within 30 days after the operative procedure, plus purulent drainage, plus isolation of organisms from a culture from the incision site, plus diagnosis by a medical officer. A 5-item definition of a patient being asymptomatic, plus afebrile on admission, plus infection occurring at least 48 hours after admission, plus the patient having a fever of >38 degrees C, plus a recognized culture from one or more bottles was used by 15.7% (95% CI, 11.3%-21.0%) of ICPs to define a case of bacteremia.

CONCLUSION

Surveillance is the core business of Australian ICPs and consumes a substantial proportion of their time. The importance of surveillance, the epidemiologic limitations of the current ACHS system, and the nonstandard methods we report indicate that improved methodology is required for case finding and reporting of nosocomial infections. Australian ICPs should complete training in the principles of surveillance and epidemiology. With this training, ICPs can work collaboratively with other health care professionals to develop epidemiologically sound, local, nosocomial surveillance systems and lobby for a voluntary, national, standardized, risk-adjusted system of targeted nosocomial surveillance.

Repeated multi-centre prevalence surveys of hospital-acquired infection in Greek hospitals. CICNet. Cretan Infection Control Network

Three prevalence studies for the estimation of hospital-acquired infections (HAIs) were carried out in eight Greek hospitals on an annual basis during the years 1994-1996. The overall prevalence of HAI was 6.8, 5.5 and 5.9% for the three years, respectively. Among these, urinary tract infections ranged from 22.4 to 38.2%, lower respiratory tract infections ranged from 21.1 to 32.6%, surgical site infections ranged from 14.6 to 22.7% and bloodstream infections ranged from 9.0 to 13.2%. The prevalence of antibiotic usage among the hospitalized patients was found to be 49.3% in 1994, 47.3% in 1995 and 52.7% in 1996. Unjustified prescription of prophylactic usage was found to be the major component of these high percentages. Appropriate use of antibiotics for prophylaxis is one of the priorities of the current infection control programmes. The development of a nationwide network for the surveillance of HAIs in Greece is planned using the experience gained.

Association rules and data mining in hospital infection control and public health surveillance

OBJECTIVES

The authors consider the problem of identifying new, unexpected, and interesting patterns in hospital infection control and public health surveillance data and present a new data analysis process and system based on association rules to address this problem.

DESIGN

The authors first illustrate the need for automated pattern discovery and data mining in hospital infection control and public health surveillance. Next, they define association rules, explain how those rules can be used in surveillance, and present a novel process and system--the Data Mining Surveillance System (DMSS)--that utilize association rules to identify new and interesting patterns in surveillance data.

RESULTS

Experimental results were obtained using DMSS to analyze Pseudomonas aeruginosa infection control data collected over one year (1996) at University of Alabama at Birmingham Hospital. Experiments using one-, three-, and six-month time partitions yielded 34, 57, and 28 statistically significant events, respectively. Although not all statistically significant events are clinically significant, a subset of events generated in each analysis indicated potentially significant shifts in the occurrence of infection or antimicrobial resistance patterns of P. aeruginosa.

CONCLUSION

The new process and system are efficient and effective in identifying new, unexpected, and interesting patterns in surveillance data. The clinical relevance and utility of this process await the results of prospective studies currently in progress.