Influence of primary care antibiotic prescribing on incidence rates of multidrug-resistant Gram-negative bacteria in hospitalised patients.

PURPOSE: Use of antibiotics can give rise to the selection of resistant bacteria. It remains unclear whether antibiotic use in primary care can influence bacterial resistance incidence in patients when hospitalised. The aim of this study is to explore the impact of prior community antibiotic usage on hospital-detected multidrug-resistant Gram-negative (MRGN) incidence rate. METHODS: This pharmacoepidemiological study was case-control in design, and was carried out in the Antrim Area Hospital (N. Ireland) in two phases. In phase 1, the controls were matched according to: age, gender, admission ward, date of admission, and age-adjusted Charlson co-morbidity index score. During the second phase, controls were selected randomly from the total population of admissions to the hospital over the 2-year study period. RESULTS: In phase 1, multivariate analysis revealed that prior exposure to the second- and third-generation cephalosporins (p = 0.004) and fluoroquinolones (p = 0.023) in primary care was associated with an increased likelihood of MRGN detection in inpatients. In phase 2, an independent relationship between an increased risk of identification of MRGN, while hospitalised was associated with: prolonged hospitalisation (p < 0.001), being elderly (p < 0.001), being female (p = 0.007), and having genitourinary disease (p < 0.001). CONCLUSION: This study provides clear evidence which supports the need to optimise antibiotic use in primary care to help reduce MRGN incidence in hospitalised patients.

A modified method for measuring antibiotic use in healthcare settings: implications for antibiotic stewardship and benchmarking.

OBJECTIVES: To determine whether adjusting the denominator of the common hospital antibiotic use measurement unit (defined daily doses/100 bed-days) by including age-adjusted comorbidity score (100 bed-days/age-adjusted comorbidity score) would result in more accurate and meaningful assessment of hospital antibiotic use. METHODS: The association between the monthly sum of age-adjusted comorbidity and monthly antibiotic use was measured using time-series analysis (January 2008 to June 2012). For the purposes of conducting internal benchmarking, two antibiotic usage datasets were constructed, i.e. 2004-07 (first study period) and 2008-11 (second study period). Monthly antibiotic use was normalized per 100 bed-days and per 100 bed-days/age-adjusted comorbidity score. RESULTS: Results showed that antibiotic use had significant positive relationships with the sum of age-adjusted comorbidity score (P = 0.0004). The results also showed that there was a negative relationship between antibiotic use and (i) alcohol-based hand rub use (P = 0.0370) and (ii) clinical pharmacist activity (P = 0.0031). Normalizing antibiotic use per 100 bed-days contributed to a comparative usage rate of 1.31, i.e. the average antibiotic use during the second period was 31% higher than during the first period. However, normalizing antibiotic use per 100 bed-days per age-adjusted comorbidity score resulted in a comparative usage rate of 0.98, i.e. the average antibiotic use was 2% lower in the second study period. Importantly, the latter comparative usage rate is independent of differences in patient density and case mix characteristics between the two studied populations. CONCLUSIONS: The proposed modified antibiotic measure provides an innovative approach to compare variations in antibiotic prescribing while taking account of patient case mix effects.

An evaluation of the impact of antibiotic stewardship on reducing the use of high-risk antibiotics and its effect on the incidence of Clostridium difficile infection in hospital settings.

OBJECTIVES: To evaluate the impact of a high-risk antibiotic stewardship programme on reducing antibiotic use and on hospital Clostridium difficile infection (CDI) incidence rates. A secondary objective was to present the possible utility of time-series analysis as an antibiotic risk classification tool. METHODS: This was an interventional, retrospective, ecological investigation in a medium-sized hospital over 6.5 years (January 2004 to June 2010). The intervention was the restriction of high-risk antibiotics (second-generation cephalosporins, third-generation cephalosporins, fluoroquinolones and clindamycin). Amoxicillin/clavulanic acid and macrolides were classified as medium-risk antibiotics based on time-series analysis findings and their use was monitored. The intervention was evaluated by segmented regression analysis of interrupted time series. RESULTS: The intervention was associated with a significant change in level of use of high-risk antibiotics (coefficient -17.3, P < 0.0001) and with a borderline significant trend change in their use being reduced by 0.156 defined daily doses/100 bed-days per month (P = 0.0597). The reduction in the use of high-risk antibiotics was associated with a significant change in the incidence trend of CDI (P = 0.0081), i.e. the CDI incidence rate decreased by 0.0047/100 bed-days per month. Analysis showed that variations in the incidence of CDI were affected by the age-adjusted comorbidity index with a lag of 1 month (coefficient 0.137051, P = 0.0182). Significant decreases in slope (coefficient -0.414, P = 0.0309) post-intervention were also observed for the monitored medium-risk antibiotics. CONCLUSIONS: The restriction of the high-risk antibiotics contributed to both a reduction in their use and a reduction in the incidence of CDI in the study site hospital. Time-series analysis can be utilized as a risk classification tool with utility in antibiotic stewardship design and quality improvement programmes.

The impact of antibiotic use on the incidence and resistance pattern of extended-spectrum beta-lactamase-producing bacteria in primary and secondary healthcare settings.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • The emergence and spread of bacteria producing extended-spectrum beta-lactamases (ESBLs) has important therapeutic and epidemiologic implications. • A key target for the establishment of hospital antibiotic stewardship is reducing the occurrence of additional antibiotic resistance. • Further research is needed to accumulate supporting evidence that reducing antibiotic use will result in a parallel reduction in antibiotic resistance. WHAT THIS STUDY ADDS: • Fluoroquinolone restriction reversed ciprofloxacin resistance in primary and secondary healthcare settings. • Fluoroquinolone restriction reduced ESBL-producing bacteria incidence rates in both the primary and secondary healthcare settings. • This study highlights the value of time-series analysis in designing efficient antibiotic stewardship. AIMS: The objective of the present study was to study the relationship between hospital antibiotic use, community antibiotic use and the incidence of extended-spectrum beta-lactamase (ESBL)-producing bacteria in hospitals, while assessing the impact of a fluoroquinolone restriction policy on ESBL-producing bacteria incidence rates. METHODS: The study was retrospective and ecological in design. A multivariate autoregressive integrated moving average (ARIMA) model was built to relate antibiotic use to ESB-producing bacteria incidence rates and resistance patterns over a 5 year period (January 2005-December 2009). RESULTS: Analysis showed that the hospital incidence of ESBLs had a positive relationship with the use of fluoroquinolones in the hospital (coefficient = 0.174, P= 0.02), amoxicillin-clavulanic acid in the community (coefficient = 1.03, P= 0.03) and mean co-morbidity scores for hospitalized patients (coefficient = 2.15, P= 0.03) with various time lags. The fluoroquinolone restriction policy was implemented successfully with the mean use of fluoroquinolones (mainly ciprofloxacin) being reduced from 133 to 17 defined daily doses (DDDs)/1000 bed days (P < 0.001) and from 0.65 to 0.54 DDDs/1000 inhabitants/day (P= 0.0007), in both the hospital and its surrounding community, respectively. This was associated with an improved ciprofloxacin susceptibility in both settings [ciprofloxacin susceptibility being improved from 16% to 28% in the community (P < 0.001)] and with a statistically significant reduction in ESBL-producing bacteria incidence rates. DISCUSSION: This study supports the value of restricting the use of certain antimicrobial classes to control ESBL, and demonstrates the feasibility of reversing resistance patterns post successful antibiotic restriction. The study also highlights the potential value of the time-series analysis in designing efficient antibiotic stewardship.

A point prevalence survey of antibiotic prescriptions: benchmarking and patterns of use.

AIM: The aim of the study was to assess current patterns of antibiotic prescribing and the impact of a hospital antibiotic policy on these practices. METHODS: The study involved collecting information regarding hospitalized patients utilizing the ESAC audit tool. RESULTS: In the study site hospital, the use of the restricted agents was low whilst the use of the non-restricted agents was high. Compliance with the hospital antibiotic guidelines was 70%. DISCUSSION: The findings identified monitoring non-restricted antibiotics and compliance with guidelines as targets for quality improvements in our hospital. Point prevalence surveys may offer a simple method of monitoring antibiotic policies, thus, informing antibiotic stewardship.

Quasiexperimental study of the effects of antibiotic use, gastric acid-suppressive agents, and infection control practices on the incidence of Clostridium difficile-associated diarrhea in hospitalized patients.

The objective of this study was to evaluate the effects of antimicrobial drug use, gastric acid-suppressive agent use, and infection control practices on the incidence of Clostridium difficile-associated diarrhea (CDAD) in a 426-bed general teaching hospital in Northern Ireland. The study was retrospective and ecological in design. A multivariate autoregressive integrated moving average (time-series analysis) model was built to relate CDAD incidence with antibiotic use, gastric acid-suppressive agent use, and infection control practices within the hospital over a 5-year period (February 2002 to March 2007). The findings of this study showed that temporal variation in CDAD incidence followed temporal variations in expanded-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.01/100 bed-days), broad-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.02/100 bed-days), fluoroquinolone use (average delay = 3 months; variation of CDAD incidence = 0.004/100 bed-days), amoxicillin-clavulanic acid use (average delay = 1 month; variation of CDAD incidence = 0.002/100 bed-days), and macrolide use (average delay = 5 months; variation of CDAD incidence = 0.002/100 bed-days). Temporal relationships were also observed between CDAD incidence and use of histamine-2 receptor antagonists (H2RAs; average delay = 1 month; variation of CDAD incidence = 0.001/100 bed-days). The model explained 78% of the variance in the monthly incidence of CDAD. The findings of this study highlight a temporal relationship between certain classes of antibiotics, H2RAs, and CDAD incidence. The results of this research can help hospitals to set priorities for restricting the use of specific antibiotic classes, based on the size-effect of each class and the delay necessary to observe an effect.

Modelling the impact of antibiotic use and infection control practices on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus: a time-series analysis.

OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide. A wide range of factors have been suggested to influence the spread of MRSA. The objective of this study was to evaluate the effect of antimicrobial drug use and infection control practices on nosocomial MRSA incidence in a 426-bed general teaching hospital in Northern Ireland. METHODS: The present research involved the retrospective collection of monthly data on the usage of antibiotics and on infection control practices within the hospital over a 5 year period (January 2000-December 2004). A multivariate ARIMA (time-series analysis) model was built to relate MRSA incidence with antibiotic use and infection control practices. RESULTS: Analysis of the 5 year data set showed that temporal variations in MRSA incidence followed temporal variations in the use of fluoroquinolones, third-generation cephalosporins, macrolides and amoxicillin/clavulanic acid (coefficients = 0.005, 0.03, 0.002 and 0.003, respectively, with various time lags). Temporal relationships were also observed between MRSA incidence and infection control practices, i.e. the number of patients actively screened for MRSA (coefficient = -0.007), the use of alcohol-impregnated wipes (coefficient = -0.0003) and the bulk orders of alcohol-based handrub (coefficients = -0.04 and -0.08), with increased infection control activity being associated with decreased MRSA incidence, and between MRSA incidence and the number of new patients admitted with MRSA (coefficient = 0.22). The model explained 78.4% of the variance in the monthly incidence of MRSA. CONCLUSIONS: The results of this study confirm the value of infection control policies as well as suggest the usefulness of restricting the use of certain antimicrobial classes to control MRSA.

Comparison of the effect of ciprofloxacin and Tazocin on the incidence of meticillin-resistant Staphylococcus aureus (MRSA) in an Intensive Care Unit.

Meticillin-resistant Staphylococcus aureus (MRSA) is a very significant agent of recalcitrant healthcare-associated infections. A major risk of acquiring such infections is thought to be modulated by the use of particular antimicrobial therapies. The aim of this research was to evaluate prospectively the impact of using either ciprofloxacin or Tazocin (piperacillin+tazobactam) on the incidence of MRSA in an Intensive Care Unit (ICU). The 1-year (2 x 6 months) cross-over study was carried out in a medium-sized (426 beds) teaching hospital. During the first 6-month period, ciprofloxacin was used as the first-line broad-spectrum antibiotic therapy of choice. During the second 6-month period, Tazocin was used as first-line therapy. The incidence of hospital-acquired MRSA (i.e. colonised and/or infected) and rates of compliance of the ICU healthcare workers to optimal hand hygiene practices were recorded throughout the study. The study observed no statistically significant differences (P = 0.1) between MRSA incidence rates in the ICU during the ciprofloxacin (4.4/1000 bed-days) or Tazocin (11.4/1000 bed-days) arms of the study. Interestingly, observing healthcare workers' hand hygiene practices throughout the entire study showed that healthcare workers adhered to these practices 59.2% of the time during the ciprofloxacin arm and 66.0% during the Tazocin arm. The low incidence rates within the unit demonstrated the importance of infection control in limiting the spread of MRSA despite the extensive use of antibiotics in a high-risk setting.

Reduction in the incidence of hospital-acquired MRSA following the introduction of a chlorine dioxide 275†ppm based disinfecting agent in a district general hospital.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile are major nosocomial pathogens whose control relies on effective antimicrobial stewardship and infection control practices. This study evaluates the impact of a chlorine dioxide-based disinfectant (275 ppm) on the incidence of hospital-acquired (HA) MRSA and HA-Clostridium difficile infection (CDI) in a district general hospital. METHODS: This study was carried out from November 2009 to September 2013. From November 2009 to October 2011 sodium dichloroisocyanurate was used for routine environmental disinfection. In November 2011, this was changed to a chlorine dioxide 275 ppm based disinfectant. This product was introduced into the hospital in a phased manner with intensive training on its use provided to all nursing, nursing auxiliary and hotel services staff. The effect of this change on the incidence of HA-MRSA and HA-CDI was assessed using segmented regression analysis of interrupted time series. In addition, the potential cost savings as a result of this intervention were assessed. RESULTS: The HA-MRSA trend from November 2009 to October 2011 significantly increased (p=0.006). Following the introduction of the chlorine dioxide-based disinfectant there was significant decrease in the HA-MRSA trend, with the monthly incidence being reduced by 0.003 cases/100 bed days (p=0.001), equating to an average of four cases per month after 12 months of use This resulted in an annual potential cost saving of £276 000. No significant effect on the incidence of HA-CDI was observed (coefficient -0.03; p=0.873). CONCLUSION: This study highlights the importance of effective environmental inanimate surface decontamination in controlling the spread of MRSA and the potential cost savings that can be achieved through decreasing HA-MRSA rates.

Multihospital outbreak of Clostridium difficile ribotype 027 infection: epidemiology and analysis of control measures.

OBJECTIVE: To report a large outbreak of Clostridium difficile infection (CDI; ribotype 027) between June 2007 and August 2008, describe infection control measures, and evaluate the impact of restricting the use of fluoroquinolones in controlling the outbreak. DESIGN: Outbreak investigation in 3 acute care hospitals of the Northern Health and Social Care Trust in Northern Ireland. INTERVENTIONS: Implementation of a series of CDI control measures that targeted high-risk antibiotic agents (ie, restriction of fluoroquinolones), infection control practices, and environmental hygiene. RESULTS: A total of 318 cases of CDI were identified during the outbreak, which was the result of the interaction between C. difficile ribotype 027 being introduced into the affected hospitals for the first time and other predisposing risk factors (ranging from host factors to suboptimal compliance with antibiotic guidelines and infection control policies). The 30-day all-cause mortality rate was 24.5%; however, CDI was the attributable cause of death for only 2.5% of the infected patients. Time series analysis showed that restricting the use of fluoroquinolones was associated with a significant reduction in the incidence of CDI (coefficient, -0.054; lag time, 4 months; P = .003). CONCLUSION: These findings provide additional evidence to support the value of antimicrobial stewardship as an essential element of multifaceted interventions to control CDI outbreaks. The present CDI outbreak was ended following the implementation of an action plan improving communication, antibiotic stewardship, infection control practices, environmental hygiene, and surveillance.

Prevalence of methicillin-resistant Staphylococcus aureus colonization in residents and staff in nursing homes in Northern Ireland.

OBJECTIVES: To determine the prevalence of, and factors associated with, methicillin-resistant Staphylococcus aureus (MRSA) colonization in residents and staff in nursing homes in one geographically defined health administration area of Northern Ireland. DESIGN: Point prevalence study. SETTING: Nursing homes. PARTICIPANTS: Residents and staff in nursing homes. MEASUREMENTS: Nasal swabs were taken from all consenting residents and staff. If relevant, residents also provided urine samples, and swabs were taken from wounds and indwelling devices. RESULTS: A total of 1,111 residents (66% of all residents) and 553 staff (86% of available staff) in 45 nursing homes participated. The combined prevalence rate of MRSA in the resident population was 23.3% (95% confidence interval (CI)=18.8-27.7%) and 7.5% in staff (95% CI=5.1-9.9%). Residents who lived in nursing homes that were part of a chain were more likely to be colonized with MRSA (odds ratio (OR)=1.91, 95% CI=1.21-3.02) than those living in independently owned facilities. Residents were also more likely to be colonized if they lived in homes in which more than 12.5% of all screened healthcare staff (care assistants and nurses) were colonized with MRSA (OR=2.46, 95% CI=1.41-4.29) or if they lived in homes in which more than 15% of care assistants were colonized with MRSA (OR=2.64, 95% CI=1.58-4.42). CONCLUSION: The findings suggest that there is substantial colonization of MRSA in nursing home residents and staff in this one administrative health area. Implementation of infection control strategies should be given high priority in nursing homes.