Does antimicrobial use density at the ward level influence monthly central line-associated bloodstream infection rates?

The aim of this study was to elucidate risk factors, including ward antimicrobial use density (AUD), for central line-associated bloodstream infection (CLABSI) as defined by the Centers for Disease Control and Prevention in a 430-bed community hospital using central venous lines with closed-hub systems. We calculated AUD as (total dose)/(defined daily dose × patient days) ×1,000 for a total of 20 drugs, nine wards, and 24 months. Into each line day data, we inputed AUD and device utilization ratios, number of central line days, and CLABSI. The ratio of susceptible strains in isolates were subjected to correlation analysis with AUD. Of a total of 9,997 line days over 24 months, CLABSI was present in 33 cases (3.3 ‰), 14 (42.4%) of which were on surgical wards out of nine wards. Of a total of 43 strains isolated, eight (18.6%) were methicillin-resistant Staphylococcus aureus (MRSA); none of the MRSA-positive patients had received cefotiam before the onset of infection. Receiver-operating characteristic analysis showed that central line day 7 had the highest accuracy. Logistic regression analysis showed the central line day showed an odds ratio of 5.511 with a 95% confidence interval of 1.936-15.690 as did AUD of cefotiam showing an odds ratio of 0.220 with 95% confidence interval of 0.00527-0.922 (P=0.038). Susceptible strains ratio and AUD showed a negative correlation (R (2)=0.1897). Thus, CLABSI could be prevented by making the number of central line days as short as possible. The preventative role of AUD remains to be investigated.

Association between ward-specific antimicrobial use density and methicillin-resistant Staphylococcu aureus surveillance: a 60-month study.

It is not known whether or not ward-specific antimicrobial use density (AUD) affects the ratio of methicillin-resistant Staphylococcus aureus (MRSA) in culture-positive S. aureus. A 60-month study was attempted to ascertain the association between inpatient MRSA ratio and ward-specific AUDs as well as the former and latter study intervals, specimen types, and ward specialty. During the study, the professionals in infection control regulated the use of broad-spectrum antimicrobials and those for MRSA. By both month and ward, the ratio of inpatients positive for MRSA to those positive for S. aureus was calculated. Factors associated with MRSA ratio included AUDs averaged for the sampling month and its previous month, outpatient MRSA ratio by age, ward specialty, specimen type, and half intervals to represent historical changes. Of a total of 4,245 strains of S. aureus isolated during the 5-year study, 2,232 strains (52.6%) were MRSA. By year, outpatient MRSA ratio at age ≥15 decreased in later years, as did inpatient MRSA ratio. Multivariate analysis for inpatient MRSA ratio revealed a positive risk in AUDs for meropenem (odds ratio [OR] 1.761; 95% confidence interval [CI] 1.761-2.637, P = 0.01), imipenem-cilastatin (OR 1.583; 95% CI 1.087-2.306, P = 0.02), ampicillin-sulbactam (OR 1.623; 95% CI 1.114-2.365, P = 0.01), and minocycline (OR 1.680; CI 1.135-2.487, P = 0.01), respiratory care ward (OR 2.292; 95% CI 1.085-4.841, P = 0.03), and outpatient MRSA ratio (OR 1.536; 95% CI 1.070-2.206, P = 0.02). Use of broad-spectrum antimicrobials, such as meropenem, imipenem-cilastatin, and ampicillin-sulbactam may increase inpatient MRSA ratio. Ward factor should be included in MRSA surveillance because of the possible effect on AUD and considering patients' backgrounds.

Is Clostridium difficile infection influenced by antimicrobial use density in wards?

This study was performed to elucidate the relationship between antimicrobial use density (AUD) and Clostridium difficile infection (CDI) manifesting as antimicrobial-associated diarrhea (AAD) in hospital wards during a 4-year period. Case definition of CDI was an adult exhibiting AAD with a daily stool frequency of three or more, arising at least 48 hours after ward admission, and fecal samples testing positive for toxin (A and/or B). Metronidazole or vancomycin was orally administered as treatment. AUDs were calculated for a total of 21 antimicrobials in a span of 48 months and nine wards. We included the average value of AUDs, representing two succeeding months of sample submission into the sample information. We also entered data on the 2-year division and intensified contact precaution for statistical analysis. Of a total of 463 cases, 95 (20.5%) were CDI-positive. Multivariate regression analysis showed odds ratios [OR] of 1.739 (95% confidence interval [CI] of 1.050 - 2.881, P = 0.032) and 1.598 (95% CI of 1.006 -2.539, P = 0.047) for clindamycin and piperacillin, respectively in AUD. Thus increased ward AUDs of clindamycin and piperacillin may run the risk of CDI.

[Drug resistance of Pseudomonas aeruginosa in four community hospitals: influence of antimicrobial use density].

We investigated the relation between hospital antimirobial use density (AUD) and minimum inhibitory concentrations (MIC) for Pseudomonas aeruginosa in four community hospitals. Subjects were a total of 476 strains isolated from urine, sputum, and pus during a total of seven years since 2002, for which 50- and 90-percentile MICs were analyzed. Hospitals A, B, and C moved in 2000, 2005, and 2009, respectively, but MIC50 and MIC90 were stable. MIC values showed significance in five drugs, in which Hospital B showed maximal values in five and Hospital D showed minimal values in four drugs. AUD values were different in nine drugs, Hospital B showing the highest data in meropenem, flomoxef, and sulbactam/cefoperazone while Hospital D having the lowest data in meropenem, ceftazidime, cefotaxime, and sulbactam/cefoperazone. Thus MIC for P aeruginosa may show resistance in the presence of high AUD with wide antimicrobial spectrum.

Association between risk of bloodstream infection and duration of use of totally implantable access ports and central lines: a 24-month study.

BACKGROUND: Prolonged use of totally implantable access ports (APs) and central lines (CLs) has been known to carry a risk of bloodstream infection (BSI), but the safe cutoff day for discontinuing use remains unknown. We performed a receiver operating characteristic (ROC) curve analysis to determine this cutoff. METHODS: A retrospective 24-month study covered a total of 22,481 days of device use. For each day of use, the following findings were recorded: patient age and sex; presence or absence of diabetes mellitus, preexisting sepsis, and renal disease; and occurrence of device-associated BSI. BSI was defined in accordance with the Centers for Disease Control and Prevention's definition of catheter-related infection. RESULTS: BSIs occurred in 81 patients with an AP, for a BSI rate of 2.81 cases per 1,000 days of use. Among the 896 patients with a CL, the BSI rate was 5.60 cases per 1,000 days of use. The ROC analysis found a cutoff time of 33 days for APs (median days of use, 48) and 10 days for CLs (median days of use, 20.5). For the total 22,481 days of use, the odds ratio between APs and CLs with respect to BSI was 0.556 (95% confidence interval [CI], 0.256-1.208; P = .138). Days of use beyond the cutoff had an odds ratio of 2.867 (95% CI, 1.823-4.507; P < .001). Among the risk factors, preexisting sepsis had an odds ratio of 7.843 (95% CI, 4.666-13.184; P < .001). CONCLUSION: Use of an AP for more than 33 days and a CL for more than 10 days may carry an increased risk of device-associated BSI. These cutoff periods are longer than those expected at the time of device placement and indicate the importance of postplacement care.

Central line-associated bloodstream infection: is the hospital epidemiology of methicillin-resistant Staphylococcus aureus relevant?

We aimed to evaluate the risk factors, including the hospital epidemiology of methicillin-resistant Staphylococcus aureus (MRSA), for central venous line-associated and laboratory-confirmed bloodstream infections (CLA-BSI and LC-BSI, respectively). The risk factors examined included the age and sex of patients, whether or not they were in the surgery service, the number of days of central line (CL) placement, the monthly number of inpatients and those positive for MRSA, and whether the standard or maximal barrier precautions were observed at CL insertion. As the outcome factors, we selected CLA-BSI and LC-BSI, while precluding repeated isolation within 28 days. Of a total of 22,723 device days in 927 patients with CL placement, we observed 81 CLA-BSIs and 40 LC-BSIs, rates of 3.56 and 1.76 (/1000 device-days), respectively. Logistic regression analysis revealed a single significant factor, CL placement of more than 30 days, with odds ratios of 3.038 [95% confidence interval (CI) 1.733-5.326; P < 0.001] for CLA-BSI and 3.227 (95% CI 1.427-7.299; P = 0.005) for LC-BSI. Both BSIs included MRSA in seven events without temporal clusters. We conclude that the factor of long CL placement outweighs other risk factors, including the hospital epidemiology of MRSA.

Risk factors for central venous catheter-related bloodstream infection: a 1073-patient study.

We intended to evaluate the risk factors for catheter-related bloodstream infection (CR-BSI) with central venous (CV) catheters. For the hub of the CV line, we used three-way stopcocks in the first year of the study and closed needleless connectors (NCs) in the second year. Background factors included the age and sex of patients; the ward; the specialty service; the CV catheter and its days of placement; and the staff compounding the intravenous infusion, i.e., either nurses, who disinfect hands-free, or pharmacists using clean benches. Outcome factors included positive culture from the blood-related samples and the body temperature estimate. Of a total of 29 221 device-days in 1073 patients, positive cultures showed an overall incidence of 2.26 per 1000 device-days. Multivariate analysis showed a higher odds ratio of positive cultures for the ICU (odds ratio [OR], 4.415; 95% confidence interval [CI], 2.054-9.490]) and for CV catheter placement for more than 30 days (OR, 7.529; 95% CI, 4.279-13.247), but no significance for male sex (OR, 1.752; 95% CI, 0.984-3.119) or for pharmacists' compounding (OR, 2.150; 95% CI, 0.974-4.749). Univariate analysis showed no significance for the following factors: age more than 70 years (OR, 0.968; 95% CI 0.561-1.641), the surgery service (OR, 1.029; 95% CI, 0.582-1.818), double-lumen CV catheters (OR, 0.841; 95% CI, 0.465-1.521), or the NC (1.107; 95% CI, 0.673-1.821). We conclude that the theoretical benefit of the NC, the abolished dead space in the hub, contributed little to the outcomes of blood-related culture. The hands-free disinfection may have resulted in comparable odds ratios for the nurses and the pharmacists compounding the infusions.