Number of comorbidities as a predictor of nosocomial infection acquisition

Impact of carbapenem resistance on the outcome of patients' hospital-acquired bacteraemia caused by Klebsiella pneumoniae

BACKGROUND

Carbapenem-resistant Enterobacteriaceae, especially Klebsiella spp., have become a major health problem recently worldwide. Since 2006 the incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP) infections has increased substantially in Israel. Bloodstream infections (BSIs) caused by these strains have been associated with high rates of treatment failure and mortality.

AIM

This study was designed to identify risk factors for carbapenem resistance among patients with healthcare-related (HCR) K. pneumoniae bacteraemia and predictors of mortality associated with HCR-CRKP bacteraemia compared with carbapenem-susceptible K. pneumoniae (CSKP).

METHODS

In this retrospective case-control study, all cases of K. pneumoniae bacteraemia during 2006-2008 were identified. Resistance patterns, underlying morbidities, risk factors for drug resistance and mortality rates were compared for patients with CRKP and CSKP bacteraemia.

FINDINGS

Two hundred and fourteen patients with CSKP bacteraemia were compared with 103 patients with CRKP bacteraemia. Severe, chronic comorbidities and prior antibiotic use were more frequent among patients with CRKP bacteraemia. On multivariate analysis prior use of macrolides and antibiotic exposure for ≥14 days remained the only independent factors associated with CRKP bacteraemia. Mortality rates of CRKP patients were significantly higher than those of CSKP patients. On multivariate analyses: bedridden status, chronic liver disease, Charlson comorbidity index ≥5, mechanical ventilation, and haemodialysis remained independently associated with mortality among patients with K. pneumoniae bacteraemia. Carbapenem resistance was not a risk factor for mortality.

CONCLUSIONS

Previous antibiotic exposure is a risk factor for CRKP-BSI. Mortality among patients with K. pneumoniae bacteraemia is associated with serious comorbidities, but not with carbapenem resistance.

[Impact on morbidity and costs of methicillin-resistant Staphylococcus aureus nosocomial pneumonia in intensive care patients]

OBJECTIVES

Prevention of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections in the intensive care units (ICU) has been recommended for several years. However, the workload and the costs of these programs are to be weighed against the benefit obtained in terms of reduction of morbidity and costs induced by the infection. The purpose of this study was to evaluate the cost and the current morbidity of the infection with MRSA in the ICU.

METHODS

In a retrospective case-control study carried out in 2004, all patients of the 6 intensive care units of a teaching hospital having developed a MRSA nosocomial infection were included. They were paired with controls on the following criteria: department, Simplified Acute Physiology Score II (SAPSII), age (+/- 5 years), type of surgery (for the surgical intensive care units). The duration of hospitalization of the paired control had to be at least equal to the time from admission to infection of the infected patient. The costs were evaluated using the following parameters: scores omega 1, 2 and 3, duration of artificial ventilation, hemodialysis, length of ICU stay, radiological procedures, surgical procedures, total antibiotic cost and other expensive drugs.

RESULTS

Twenty-one patients with MRSA infection were included. All had nosocomial pneumonia. The 21 paired patients were similar with regard to both initial criteria and sex. Hospital mortality was not different between the 2 groups (cases=8; controls=6; p=0.41), as well as median duration of hospital stay (cases=41 days; controls=43 days; p=0.9). The duration of mechanical ventilation, number of hemodialysis or hemofiltration sessions, number of radiological procedures were similar in both groups. The total omega score was not significantly different between cases (median 435; IQR: 218-579) and controls (median 281, IQR: 231-419; p=0.55). The median duration of isolation was 12 days for cases and 0 day for controls (p=0.0007). The pharmaceutical expenditure was significantly higher in cases (median: 1414euro; IQR: 795-4349), by comparison with the controls (median: 877euro, IQR: 687-2496) (p=0.049).

CONCLUSION

In the ICU having set up a policy intended to reduce the risk of MRSA nosocomial infections, MRSA pneumonia does not seem to involve major additional morbidity, as compared to a control population matched for similar severity of illness. It increases modestly the use of the medical resources.

Long-term outcomes from nosocomial infections in persons with spinal cord injuries and disorders

BACKGROUND

Nosocomial infection may contribute to poor long-term consequences in persons who have spinal cord injuries and disorders (SCI&D).

METHODS

This is a cohort study of individuals who had SCI&D and were hospitalized at least once during 2002. They were followed for 3 years to assess inpatient (IP) admissions, total IP length of stay (LOS), outpatient (OP) visits, and mortality. Count data models and a Cox proportional hazards model were used to assess the relationship between previous infection and subsequent IP and OP use and long-term mortality, respectively.

RESULTS

Of persons who had SCI&D, 59% had at least one nosocomial infection. Multivariable regression indicated that veterans who had SCI&D had more IP admissions (b = 0.405; P < .0001) and longer IP LOS (b = 0.843; P < .0001) if they had a previous infection; however, infection status was not a predictor of future OP visits. Survival time was lower (913.93 versus 1034.75 days, P = .004) in the infection group. Death rate was higher in the nosocomial infection group (30.11% versus 10.77%; P = .004), but the association did not achieve significance in the Cox proportional hazards model (P = .12).

CONCLUSIONS

Nosocomial infections have serious subsequent consequences that result in future hospitalization and shorter survival. Efforts to prevent nosocomial infections are needed to reduce long-term adverse effects in persons who have SCI&D.

Risk factors for nosocomial infections caused by gram-negative bacilli. The Hellenic Antibiotic Resistance Study Group

Two hundred and ninety-nine Gram-negative hospital-acquired infections from 257 patients, consecutively identified during one month (November 1992) in five hospitals in the greater Athens area, were divided into four groups on the basis of the bacterium isolated: Group 1 (Escherichia coli group) included infections owing to E. coli, Group 2 (Proteus group) consisted of infections owing to Proteus spp. and Providencia spp., Group 3 (Kiebsiella/Enterobacter group) involved infections owing to Kiebsiella spp., Enterobacter spp., Citrobacter spp. and Serratia spp. Infections owing to Pseudomonas spp. and other non-fermenters were allocated into Group 4 (non-fermenters group). The four groups were studied in relation to risk factors including the duration of hospitalization, type of ward, underlying disease, history of operation, medical procedures/devices and antimicrobial therapy. A stepwise multiple logistic regression technique (SPSS Inc) was used to analyse the data, and the three groups (the Proteus group, the Klebsiella/Enterobacter group and the non-fermenters group) were analysed separately against the E. coli group. Infections with the Kiebsiella/Enterobacter group were associated with: (a) length of hospital stay before the infection, (b) treatment with newer antibiotics, and (c) hospitalization in an intensivecare unit (ICU). Infections with non-fermenters were associated with: (a) length of hospital stay before infection, (b) a urinary catheter, (c) type of disease (chronic infection being negatively associated), (d) treatment with newer antibiotics and (e) hospitalization in an ICU. Proteus group infections were associated with (a) length of hospital stay before infection, (b) treatment with newer antibiotics and (c) operation during present hospitalization (negative association). Interestingly, no specific hospitals were identified as risk factors. Identification of patients at risk for acquiring an infection owing to a nosocomial pathogen is vital in the development of a preventive strategy for hospital-acquired infections.

Severity of illness classification for infection control departments: a study in nosocomial pneumonia

BACKGROUND

A subjective severity of illness classification was evaluated in a study of nosocomial pneumonia. This is a 5-category system based on the determination of the control of underlying illness and the risk of death during current hospital admission.

METHODS

A case-control study was performed with 128 cases of nosocomial pneumonia and 252 control patients. An additional 60 case and 90 control patients were used to compare this classification with APACHE II scoring in intensive care unit patients.

RESULTS

In univariate analysis, the severity illness classification was significantly associated with nosocomial pneumonia risk (p < 0.01). APACHE II adequately predicted mortality rate but was not statistically significantly associated with nosocomial pneumonia risk among intensive care unit patients. In logistic regression analysis, the severity of illness classification, surgery, age, nasogastric tube placement, and histamine blockers each showed significant independent association with nosocomial pneumonia.

CONCLUSIONS

The role of the severity of illness classification for risk stratification in nosocomial pneumonia is valid. Its roles in the evaluation of surgical wound infection, nosocomial bacteremia, and quality of care remain to be determined in subsequent studies.

Computerized identification of patients at high risk for hospital-acquired infection

Surveillance for hospital-acquired infections is required in U.S. hospitals, and statistical methods have been used to predict the risk of infection. We used the HELP (Health Evaluation through Logical Processing) Hospital Information System at LDS Hospital to develop computerized methods to identify and verify hospital-acquired infections. The criteria for hospital-acquired infection are standardized and based on the guidelines of the Study of the Efficacy of Nosocomial Infection Control and the Centers for Disease Control. The computer algorithms are automatically activated when key items of information, such as microbiology results, are reported. Computer surveillance identified more hospital-acquired infections than did traditional methods and has replaced manual surveillance in our 520-bed hospital. Data on verified hospital-acquired infections are electronically transferred to a microcomputer to facilitate outbreak investigation and the generation of reports on infection rates. Recently, we used the HELP system to employ statistical methods to automatically identify high-risk patients. Patient data from more than 6000 patients were used to develop a high-risk equation. Stepwise logistic regression identified 10 risk factors for nosocomial infection. The HELP system now uses this logistic-regression equation to monitor and determine the risk status for all hospitalized patients each day. The computer notifies infection control practitioners each morning of patients who are newly classified as being at high risk. Of 605 hospital-acquired infections during a 6-month period, 472 (78%) occurred in high-risk patients, and 380 (63%) were predicted before the onset of infection. Computerized regression equations to identify patients at risk of having hospital-acquired infections can help focus prevention efforts.

The infection control practitioner: an action plan for the 1990s

Some articles have suggested that to survive in the 1990s an infection control practitioner (ICP) will have to be "smarter, brighter, or gone"--they assume that new initiatives for hospital peer review (utilization review, risk management, antibiotic use review, and quality assurance) soon will swallow up the ICP and the infection control program. This article questions that assumption. It reviews data supporting the continuing need for hospital infection control programs and presents information suggesting that the need for the ICP will increase rather than decline during the 1990s. Four essential characteristics for infection control programs are listed, and skills that make the ICP a valuable resource for other peer review programs are described. Several ways that the ICP can (and must) bring this information to the attention of other hospital personnel are suggested. Such actions help assure recognition of the continuing important role of the ICP and the hospital infection control program in each U.S. hospital and long-term care institution.