Correlation between antibiotic consumption and resistance of bloodstream bacteria in a University Hospital in North Eastern Italy, 2008-2014

Relationship between Antibiotic Consumption and Resistance: A Systematic Review

Background

Unreserved use of antibiotics exerted selective pressure on susceptible bacteria, resulting in the survival of resistant strains. Despite this, the relationship between antibiotic resistance (ABR) and antibiotic consumption (ABC) is rarely studied. This systematic review aims to review the relationship between ABC and ABR from 2016 to 2022.

Methods

Articles published over 7 years (2016-2022) were searched from December 23 to 31, 2022. The search strategy was developed by using keywords for ABC and ABR. From 3367 articles, 58 eligible articles were included in the final review.

Results

The pooled ABC was 948017.9 DPDs and 4108.6 DIDs where over 70% of antibiotics were from the Watch and Reserve category based on the WHO AWaRe classification. The average pooled prevalence of ABR was 38.4%. Enterococcus faecium (59.4%), A. baumannii (52.6%), and P. aeruginosa (48.6%) were the most common antibiotic-resistant bacteria. Cephalosporins (76.8%), penicillin (58.3%), and aminoglycosides (52%) were commonly involved antibiotics in ABR. The positive correlation between ABR and consumption accounted for 311 (81%). The correlation between ABR P. aeruginosa and ABC accounted for 87 (22.7%), followed by 78 (20.3%) and 77 (20.1%) for ABR E. coli and K. pneumoniae with ABCs, respectively. Consumption of carbapenems and fluoroquinolones was most commonly correlated with resistance rates of P. aeruginosa, K. pneumoniae, E. coli, and A. baumannii.

Conclusion

There is a positive correlation between ABC and the rate of ABR. The review also revealed a cross-resistance between the consumption of different antibiotics and ABR. Optimizing antibiotic therapy and reducing unnecessary ABC will prevent the emergence and spread of ABR. Thus, advocating the implementation of stewardship programs plays a pivotal role in containing ABR.

Correlation between antibiotic use and resistance of gram-negative bacteria at a university hospital in Japan from 2013 to 2021: a study using the Japan Surveillance for Infection Prevention and Healthcare Epidemiology system

OBJECTIVES

The Japan Surveillance for Infection Prevention and Healthcare Epidemiology (J-SIPHE) system aggregates information related to antimicrobial resistance (AMR) measures. We aimed to investigate the correlation between antibiotic use and AMR at a university hospital from 2013 to 2021 in a time series analysis using the J-SIPHE system. We also studied this correlation in each ward (inter-ward analysis).

METHODS

Data on antibiotic use and resistance rates were collected from the J-SIPHE system, except for the resistance rate in each ward, which was calculated from the source data prepared for this system.

RESULTS

Piperacillin/tazobactam use was positively correlated with piperacillin/tazobactam resistance in Escherichia coli and Klebsiella pneumoniae in the inter-ward analysis, and in Pseudomonas aeruginosa in both analyses. Carbapenem use was positively correlated with meropenem resistance in Enterobacter cloacae in the time series analysis and in P. aeruginosa in both analyses, and imipenem/cilastatin resistance in P. aeruginosa in inter-ward analysis. Quinolone use was positively correlated with levofloxacin resistance in E. coli in both analyses, and in K. pneumoniae in inter-ward analysis.

CONCLUSIONS

This is the first study to investigate the correlation between antibiotic use and AMR at a single hospital in time series and inter-ward analyses using the J-SIPHE system and data prepared for this system, suggesting that this system may be useful for promoting AMR measures.

A two-year retrospective study of multidrug-resistant Acinetobacter baumannii respiratory infections in critically Ill patients: Clinical and microbiological findings

BACKGROUND

Acinetobacter baumannii infection is a serious public health problem because it is highly resistant to antimicrobial therapy and causes a high fatality rate in critically ill patients. The aim of the study is to examine the demographics, microbiological findings, clinical presentation, and outcomes of multi-drug-resistant Acinetobacter baumannii respiratory infections in adult ICU intubated patients during COVID-19 pandemic.

METHODS

This study included 115 mechanically ventilated adult ICU patients who had multi-drug-resistant Acinetobacter baumannii retrieved from respiratory samples during the COVID-19 pandemic in Albaha, Saudi Arabia. The information was obtained from medical and laboratory files. Univariate analysis was used to compare gender, COVID-19 infection, and outcomes.

RESULTS

The rate of Acinetobacter baumanni respiratory infections among adult ICU patients was 6.2 %. Almost 93 % developed ventilator-associated pneumonia, and five of them developed bacteremia. The isolates had significant antibiotic resistance patterns, of which 3 % were pandrug-resistant bacteria. The death rate was 74 %, with major risk factors including sepsis, septic shock, VAP, liver diseases, and the use of inappropriate antibiotic therapy that lacked both colistin and tigecycline. Patients with COVID-19 coinfection had worse outcomes compared to non-COVID-19 patients.

CONCLUSIONS

The identification of MDR-AB as a threat highlights the importance of surveillance studies in this region.

Correlation between antibiotic use and antibiotic resistance: A multicenter study using the Japan Surveillance for Infection Prevention and Healthcare Epidemiology (J-SIPHE) system in Hokkaido, Japan

BACKGROUND

The Japan Surveillance for Infection Prevention and Healthcare Epidemiology (J-SIPHE) system aggregates information related to antimicrobial resistance (AMR) measures in participating medical institutions nationwide and is intended to be used for promotion of AMR measures in participating facilities and their communities. This multicenter study aimed to determine the usefulness of the J-SIPHE system for evaluating the correlation between antibiotic use and antibiotic resistance in Hokkaido, Japan.

METHODS

Data on antibiotic use and detection rate of major resistant Gram-negative bacteria at 19 hospitals in 2020 were collected from the J-SIPHE system, and data correlations were analyzed using JMP Pro.

RESULTS

The detection rate of carbapenem-resistant Pseudomonas aeruginosa was significantly positively correlated with carbapenem use (Spearman's ρ = 0.551; P = .015). There were significant positive correlations between the detection rate of fluoroquinolone-resistant Escherichia coli and the use of piperacillin/tazobactam, carbapenems, and quinolones [ρ = 0.518 (P = .023), ρ = 0.76 (P < .001), and ρ = 0.502 (P = .029), respectively].

CONCLUSIONS

This is the first multicenter study to investigate the correlation between antibiotic use and antibiotic resistance using the J-SIPHE system. The results suggest that using this system may be beneficial for promoting AMR measures.

Correlation Between Individual Child-Level Antibiotic Consumption and Antibiotic-Resistant Among Commensal Escherichia coli: Results from a Cohort of Children Aged 1-3 Years in Rural Ujjain India

Background

The global expansion of antibiotic-resistant bacteria is a serious concern and is increasing worldwide in both pathogenic and commensal bacteria. The study determined the correlation between individual child-level antibiotic consumption and antibiotic resistance among the commensal Escherichia coli (E.coli) in a cohort of 125 children in rural Ujjain, India.

Methods

During a two-year period between August 2014 and September 2016, stool samples were collected at seven-time points from a cohort of 125 children; aged 1–3. A total of six colonies of E.coli per stool sample were collected for antibiotic susceptibility testing. Antibiotic consumption data was collected during the healthcare-seeking follow–up done during the same period. At each of the seven-time points correlation between antibiotic consumption (Defined Daily Dose-DDD/100 patient-days) and antibiotic resistance (number of resistant isolates) was analyzed independently using the Spearman correlation coefficient. Further, mixed-effects logistic regression models were built to study correlation between child-level consumption of penicillin with the number of E.coli isolates resistant to ampicillin, consumption of cephalosporin with resistance to cefotaxime and ceftazidime, consumption of fluoroquinolones with resistance to nalidixic acid and consumption of cotrimoxazole with resistance to cotrimoxazole.

Results

Out of 756 illness episodes reported in 125 children 42% were with antibiotic prescriptions and reported a total antibiotic consumption of 55DDD/100 patient-days. The most common antibiotics used were cefixime (J01DD08;72 DDD/100patient/days) followed by ofloxacin (J01MA01;51DDD/100patient-days), cefpodoxime (J01DD13;38DDD/100patient-days) and amoxicillin (J01CA04;28DDD/100patient-days). The highest percentage of resistance was found to the ampicillin (67%) followed by nalidixic acid (52%) and cefotaxime (44%) and when summarized, more than 90% were resistant to cefotaxime, ceftazidime, and co-trimoxazole in commensal E.coli isolates. The consumption of cephalosporins showed weak positive correlation with the resistance to cefotaxime (Coefficient±SE=0.13 ± 0.09,p<0.001).

Conclusion

Our findings showed no correlation between individual-level antibiotic consumption and resistance development in commensal E.coli in a rural community environment.

Correlation between Carbapenem Consumption and Carbapenems Susceptibility Profiles of Acinetobacter baumannii and Pseudomonas aeruginosa in an Academic Medical Center in Thailand

The emergent issue of carbapenem-resistant Acinetobacter baumannii (A. baumannii) and Pseudomonas aeruginosa (P. aeruginosa) is a major problem in Thailand. The wide use of carbapenems can increase selective pressure of bacterial resistance. The objective of this study was to determine the relationship between carbapenem consumption and the susceptibility rates of A. baumannii and P. aeruginosa, including multi-drug resistance (MDR) strains. This was a retrospective study. Carbapenem consumption and susceptibility profiles were collected from 2007 to 2013 at the Her Royal Highness Princess Maha Chakri Sirindhorn Medical Center, Thailand. We found that the susceptibility rate of A. baumannii to imipenem and meropenem from the sputum and the bronchoalveolar lavage (BAL) specimens was significantly decreased during the study period, but no significant change was found in the P. aeruginosa data. The relationship between carbapenem consumption and the susceptibility rate of A. baumannii had a clear association with the use of ertapenem. We found a statistically significant negative correlation between ertapenem consumption and the susceptibility rate of A. baumannii to imipenem (r = −0.91; p = 0.004) and meropenem (r = −0.97; p = 0.000) in the data from the non-ICU wards. In addition, imipenem use had a moderate negative correlation with the MDR P. aeruginosa data but no statistical significance (r = −0.714; p > 0.05). In conclusion, our study suggested there is an association between carbapenem use and the susceptibility of A. baumannii and P. aeruginosa. Notwithstanding this, information on ecological factors should be considered for further study. These findings showed the need to optimize the carbapenem prescription policy. Avoiding carbapenem overuse and rethinking the appropriate initial therapy might decrease the rate of resistant organisms.

Trends of Antibiotic Use and Expenditure After an Intensified Antimicrobial Stewardship Policy at a 2,200-Bed Teaching Hospital in China

Objective: This study aimed to evaluate the effects of intensified Chinese special rectification activity on clinical antibiotic use (CSRA) policy on a tertiary-care teaching hospital. Methods: A 48-month longitudinal dataset involving inpatients, outpatients, and emergency patients were collected. Study period included pre-intervention stage (adopting soft measures like systemic training) and post-intervention stage (applying antibiotic control system to intensify CSRA policy). Antibiotic use was evaluated by antibiotic use rate (AUR) or antibiotic use density (AUD). Economic indicator was evaluated by antibiotic cost in prescription or antibiotic expenditure in hospitalization. Data was analyzed by interrupted time series (ITS) analysis. Results: The medical quality indicators remained stable or improved during the study period. AUR of inpatients (AURI) declined 0.553% per month (P = 0.025) before the intervention and declined 0.354% per month (P = 0.471) after the intensified CSRA policy was implemented. AUD, expressed as defined daily doses per 100 patients per day (DDDs/100PD), decreased by 1.102 DDDs/100PD per month (P = 0.021) before and decreased by 0.597 DDDs/100PD per month (P = 0.323) thereafter. The ratio of antibiotic expenditure to medication expenditure (AE/ME) decreased by 0.510% per month (P = 0.000) before and fell by 0.096% (P = 0.000) per month thereafter. AE per patient decreased by 25.309 yuan per month (P = 0.002) before and decreased by 7.987 yuan per month (P = 0.053) thereafter. AUR of outpatient (AURO) decreased by 0.065% per month before (P = 0.550) and decreased by 0.066% per month (P = 0.994) thereafter. The ratio of antibiotic cost to prescription cost in outpatient (ACO/PCO) decreased by 0.182% per month (P = 0.506) before and decreased by 0.216% per month (P = 0.906) thereafter. AUR of emergency patient (AURE) decreased by 0.400% per month (P = 0.044) before and decreased by 0.092% per month (P = 0.164) thereafter. The ratio of antibiotic cost to prescription cost in emergency patient (ACE/PCE) decreased by 0.616% per month (P < 0.001) before and decreased by 0.151% per month (P < 0.001) thereafter. Conclusions: Implementation of CSRA policy was associated with declining antibiotic use and antibiotic expenditure in inpatients, outpatients, and emergency patients. However, it is also important to note that the declining trend of antibiotic consumption slowed due to the limited capacity for decline in the later stages of CSRA intervention.

Trends and correlation between antibacterial consumption and carbapenem resistance in gram-negative bacteria in a tertiary hospital in China from 2012 to 2019

Background

To investigate the trends and correlation between antibacterial consumption and carbapenem resistance in Gram-negative bacteria from 2012 to 2019 in a tertiary-care teaching hospital in southern China.

Methods

This retrospective study included data from hospital-wide inpatients collected between January 2012 and December 2019. Data on antibacterial consumption were expressed as defined daily doses (DDDs)/1000 patient-days. Antibacterials were classified according to the Anatomical Therapeutic Chemical (ATC) classification system. The trends in antimicrobial usage and resistance were analyzed by linear regression, while Pearson correlation analysis was used for assessing correlations.

Results

An increasing trend in the annual consumption of tetracyclines, β-lactam/β-lactamase inhibitor (BL/BLI) combinations, and carbapenems was observed (P < 0.05). Carbapenem resistance in Acinetobacter baumannii (A. baumannii) significantly increased (P < 0.05) from 18% in 2012 to 60% in 2019. Moreover, significant positive correlations were found between resistance to carbapenems in A. baumannii (P < 0.05) and Escherichia coli (E. coli; P < 0.05) and consumption of carbapenems, while the resistance rate of A. baumannii to carbapenems was positively correlated with cephalosporin/β-lactamase inhibitor (C/BLI) combinations (P < 0.01) and tetracyclines usage (P < 0.05). We also found that use of quinolones was positively correlated with the resistance rate of Burkholderia cepacia (B. cepacia) to carbapenems (P < 0.05), and increasing uses of carbapenems (P < 0.01) and penicillin/β-Lactamase inhibitor (P/BLI) combinations (P < 0.01) were significantly correlated with reduced resistance of Enterobacter cloacae (E. cloacae) to carbapenems.

Conclusion

These results revealed significant correlations between consumption of antibiotics and carbapenem resistance rates in Gram-negative bacteria. Implementing proper management strategies and reducing the unreasonable use of antibacterial drugs may be an effective measure to reduce the spread of carbapenem-resistant Gram-negative bacteria (CRGN), which should be confirmed by further studies.

The effect of an antibiotic stewardship program on tigecycline use in a Tertiary Care Hospital, an intervention study

Background

A drug-oriented antibiotic stewardship intervention targeting tigecycline utilization was launched at Makassed General Hospital, Beirut, Lebanon, in 2016 as a part of a comprehensive Antibiotic Stewardship Program (ASP). In this study, we evaluated the effect of this intervention on changing tigecycline prescription behavior in different types of infections, patient outcome and mortality, along with tigecycline drug use density, when compared to an earlier period before the initiation of ASP.

Methods

This is a retrospective chart review of all adult inpatients who received tigecycline for more than 72 h between Jan-2012 and Dec-2013 [period (P) 1 before ASP] and between Oct-2016 and Dec-2018 [period (P) 2 during ASP].

Results

Tigecycline was administered to 153 patients during P1 and 116 patients during P2. The proportion of patients suffering from cancer, those requiring mechanical ventilation, and those with hemodynamic failure was significantly reduced between P1 and P2. The proportion of patients who received tigecycline for FDA-approved indications increased from 19% during P1 to 78% during P2 (P < 0.001). On the other hand, its use in off-label indications was restricted, including ventilator-associated pneumonia (26.1% in P1, 3.4% in P2, P < 0.001), hospital-acquired pneumonia (19.6% in P1, 5.2% in P2, P = 0.001), sepsis (9.2% in P1, 3% in P2, P = 0.028), and febrile neutropenia (15.7% in P1, 0.9% in P2, P < 0.001). The clinical success rate of tigecycline therapy showed an overall significant increase from 48.4% during P1 to 65.5% during P2 (P = 0.005) in the entire patient population. All-cause mortality in the tigecycline-treated patients decreased from 45.1% during P1 to 20.7% during P2 (P < 0.0001). In general, mean tigecycline consumption decreased by 55% between P1 and P2 (P < 0.0001).

Conclusion

The drug-oriented ASP intervention targeting tigecycline prescriptions improved its use and patient outcomes, where it helped curb the over-optimistic use of this drug in off-label indications where it is not a suitable treatment option.

Ten-year trends in antibiotic usage at a tertiary care hospital in Korea, 2004 to 2013

BACKGROUND/AIMS

This study was performed to evaluate trends in antibiotic usage at a tertiary care hospital in Korea.

METHODS

This study collated antibiotic prescription data and total patient days for inpatients at a tertiary care hospital in Korea between 2004 and 2013. The consumption of each class of antibiotic was converted to defined daily dose (DDD)/1,000 patient-days. We defined 3rd generation cephalosporins, 4th generation cephalosporins, β-lactam/β-lactamase inhibitors, and fluoroquinolones as broad-spectrum antibiotics; carbapenems, tigecycline, glycopeptides, oxazolidinone, and polymyxin were defined as antibiotics against multidrug-resistant (MDR) pathogens. Other antibiotic classes were defined as nonbroad-spectrum antibiotics.

RESULTS

Mean antibiotic consumption was 920.69 DDD/1,000 patient-days. The proportions of broad-spectrum antibiotics, antibiotics against MDR pathogens, and nonbroad-spectrum antibiotics were 41.8% (384.48/920.69), 3.5% (32.24/920.69), and 54.7% (503.97/920.69), respectively. Consumption of broad-spectrum antibiotics (coefficient for time 0.141; p = 0.049) and antibiotics against MDR pathogens (coefficient for time 0.185; p < 0.001) showed a significant increasing trend over the study period. Nonbroad-spectrum antibiotic consumption showed a significant decreasing trend over the study period (coefficient for time -2.601; p < 0.001).

CONCLUSION

Over the 10-year period, a stepwise increase in the consumption of broad-spectrum antibiotics and antibiotics against MDR pathogens was observed at a tertiary care hospital in Korea. Conversely, during the same period, nonbroad-spectrum antibiotic consumption showed a significant decreasing trend.

Relationship Between Antimicrobial Prescribing and Antimicrobial Resistance Among UTI Patients at Buraidah Central Hospital, Saudi Arabia

Introduction:

Most of the decisions regarding diagnosis and treatment are based on laboratory test results. Urinary tract infections (UTIs) are among the most common infections in humans. The changing antimicrobial sensitivity in UTI requires appropriate antibiotics. Antimicrobial resistance is an emerging problem in the Kingdom of Saudi Arabia where the complete reversal of antimicrobial resistance is difficult due to irrational use of antibiotics.

Objectives:

This study aimed to determine the most common bacterial agents causing UTI in different seasons among patients who were admitted to Buraidah Central Hospital (BCH), Saudi Arabia. The study also evaluated the link between prescribing and resistance toward antimicrobials.

Materials and Methods:

A 6-month retrospective study was conducted among adult patients who were admitted to the inpatient department at BCH. A total of 379 files were collected from microbiological laboratory for inpatients.

Results:

Most UTI-causing bacteria prevailed in the same season. Of 15 bacterial strains, 12 were significantly correlated with 20 (of a total of 40) antibiotics that were used. Most bacteria were gram-negative. Gram-negative bacilli including Escherichia coli, Klebsiella spp., and Pseudomonadaceae and gram-positive Enterococcus faecalis were most frequently causing UTIs.

Conclusion:

Overall prevalence of antibiotic resistance was negative in bacterial isolates. However, the relationship between antimicrobial prescribing and antimicrobial resistance was significantly negative among UTI patients in BCH, Saudi Arabia.

Trends and correlation between antibiotic usage and resistance pattern among hospitalized patients at university hospitals in Korea, 2004 to 2012: A nationwide multicenter study

The aim of this study was to evaluate the changing pattern of antibiotic usage and antimicrobial resistance of bacterial pathogens among hospitalized patients in Korea. We simultaneously investigated the correlation between antimicrobial resistance and antibiotic consumption.Data on total antibiotic prescriptions, patient days, and antimicrobial sensitivity tests among inpatients from 6 university hospitals in Korea in 2004, 2008, and 2012 were collected. The consumption of each antibiotic class was converted to defined daily dose/1000 patient-days by using the anatomical therapeutic chemical classification system by the World Health Organization. We defined third-generation cephalosporins (3rd CEPs), fourth-generation cephalosporins, beta-lactam/beta-lactamase inhibitors, and fluoroquinolones (FQs) as broad-spectrum antibiotics and carbapenems, tigecycline, glycopeptides, oxazolidinone, and polymyxin as antibiotics against multidrug-resistant (MDR) pathogens.A 15.1% decrease in total antibiotic consumption was observed in 2012 compared to that observed in 2004. In contrast, a 10.2% and 70.7% increase in broad-spectrum antibiotics and antibiotics against MDR pathogens were observed, respectively, in the same period. The resistance rate of Escherichia coli to 3rd CEPs (17.6% in 2004, 21.7% in 2008, and 33.8% in 2012, P <.001) and ciprofloxacin (37.5% in 2004, 38.7% in 2008, and 46.6% in 2012, P = .001) demonstrated a significantly increasing trend. Similarly, the resistance rate of Klebsiella pneumoniae to 3rd CEPs (34.3% in 2004, 33.7% in 2008, and 44.5% in 2012, P <.001) gradually increased. Resistance of Acinetobacter baumanii and Pseudomonas aeruginosa to imipenem significantly increased throughout the study period (A baumanii: 8.9% in 2004, 40.8% in 2008, and 65.3% in 2012, P <.001; P aeruginosa: 25.1% in 2004, 31.5% in 2008, and 29.7% in 2008, P = .050).The consumption of carbapenems and FQs demonstrated significant positive correlation for resistance of E coli or K pneumoniae to 3rd CEPs as well as E coli or K pneumoniae to ciprofloxacin. Increasing resistance of A baumanii to ciprofloxacin was significantly correlated with increasing consumption of FQs; increasing resistance of A baumanii to imipenem was significantly correlated with increasing consumption of carbapenems.In conclusion, overall antimicrobial resistance increased and consumption of broad-spectrum antibiotics and antibiotics against MDR pathogens subsequently increased in Korean hospitals.

Association between antibiotic consumption and the rate of carbapenem-resistant Gram-negative bacteria from China based on 153 tertiary hospitals data in 2014

Background

This study aimed to investigate the relationship between the rate of carbapenem-resistant Gram-negative bacteria and antibiotic consumption intensity in 153 tertiary hospitals from China in 2014.

Methods

A retrospective study using national surveillance data from 2014 was conducted. Data on the annual consumption of each antibiotic, as well as the rate of carbapenem-resistant Gram-negative bacteria, were collected from each participating hospital, and the correlation between antibiotic consumption and carbapenem- resistant rate was analyzed.

Results

The overall antibiotic consumption intensity among the hospitals varied between 23.93 and 86.80 defined daily dosages (DDDs) per 100 patient-days (median, 46.30 DDDs per 100 patient-days). Cephalosporins were the most commonly used antibiotic, followed by quinolones, penicillins, and carbapenems, and the rate of carbapenem-resistant Gram-negative bacteria from each hospital varied. The correlations between carbapenem consumption intensity and rate of carbapenem resistance revealed correlation factors of 0.271 for Escherichia coli (p < 0.01), 0.427 for Klebsiella pneumoniae (p < 0.01), 0.463 for Pseudomonas aeruginosa (p < 0.01), and 0.331 for Acinetobacter baumannii (p < 0.01).

Conclusions

A significant relationship existed between the carbapenem consumption and the rates of carbapenem-resistant gram negative bacilli. Rational use of carbapenems should be implemented to address the issue of carbapenem resistance in hospitals.

Electronic supplementary material

The online version of this article (10.1186/s13756-018-0430-1) contains supplementary material, which is available to authorized users.

A few antibiotics can represent the total hospital antibiotic consumption

Background

Appropriate antibiotic use has become an important issue. However, collecting data on the use of all antibiotics in a hospital is difficult without an advanced computerized system and dedicated staff. This paper examines if 1–3 antibiotics can satisfactorily represent the total antibiotic consumption at the hospital level.

Methods

We collected antibiotic data from six large university hospitals in Korea for some years between 2004 and 2012. Since the total antibiotics consist of a few chosen representative antibiotics and the rest, we used those chosen antibiotics along with additional variables constructed only with t (time) such as t, t², and t³ to capture the time trend and whether t belongs to each month or not to capture the monthly variations. The ordinary least squares method was used to explain the total antibiotic amount with these variables, and then the estimated model was employed to predict the use for 2013. To determine which antibiotics were the most representative in tracking general trends in antibiotic use over time, we tried various combinations of antibiotics to find the combination that best minimized the 2013 prediction error.

Results

We found that fluoroquinolones and aminoglycosides were the most representative, followed by beta-lactam/beta-lactamase inhibitors and 4th-generation and 3rd-generation cephalosporins. The mean prediction error over 12 months in 2013 with these few antibiotics was only 1–3% of the monthly antibiotic consumption amount.

Conclusions

The total antibiotic consumption amount at the hospital level can be represented sufficiently by a few antibiotics, such as fluoroquinolones and aminoglycosides, which means that hospitals can save resources by tracing only the usage of those few antibiotics instead of the entire inventory. Since the choice of fluoroquinolones and aminoglycosides is based solely on our Korean data, other hospitals may follow the same modelling methodology to find their own representative antibiotics.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3132-7) contains supplementary material, which is available to authorized users.

Antimicrobial resistance (AMR) nanomachines-mechanisms for fluoroquinolone and glycopeptide recognition, efflux and/or deactivation

In this review, we discuss mechanisms of resistance identified in bacterial agents Staphylococcus aureus and the enterococci towards two priority classes of antibiotics-the fluoroquinolones and the glycopeptides. Members of both classes interact with a number of components in the cells of these bacteria, so the cellular targets are also considered. Fluoroquinolone resistance mechanisms include efflux pumps (MepA, NorA, NorB, NorC, MdeA, LmrS or SdrM in S. aureus and EfmA or EfrAB in the enterococci) for removal of fluoroquinolone from the intracellular environment of bacterial cells and/or protection of the gyrase and topoisomerase IV target sites in Enterococcus faecalis by Qnr-like proteins. Expression of efflux systems is regulated by GntR-like (S. aureus NorG), MarR-like (MgrA, MepR) regulators or a two-component signal transduction system (TCS) (S. aureus ArlSR). Resistance to the glycopeptide antibiotic teicoplanin occurs via efflux regulated by the TcaR regulator in S. aureus. Resistance to vancomycin occurs through modification of the D-Ala-D-Ala target in the cell wall peptidoglycan and removal of high affinity precursors, or by target protection via cell wall thickening. Of the six Van resistance types (VanA-E, VanG), the VanA resistance type is considered in this review, including its regulation by the VanSR TCS. We describe the recent application of biophysical approaches such as the hydrodynamic technique of analytical ultracentrifugation and circular dichroism spectroscopy to identify the possible molecular effector of the VanS receptor that activates expression of the Van resistance genes; both approaches demonstrated that vancomycin interacts with VanS, suggesting that vancomycin itself (or vancomycin with an accessory factor) may be an effector of vancomycin resistance. With 16 and 19 proteins or protein complexes involved in fluoroquinolone and glycopeptide resistances, respectively, and the complexities of bacterial sensing mechanisms that trigger and regulate a wide variety of possible resistance mechanisms, we propose that these antimicrobial resistance mechanisms might be considered complex 'nanomachines' that drive survival of bacterial cells in antibiotic environments.

Spread of Vancomycin-Resistant Enterococcus faecium Isolates Despite Validated Infection Control Measures in an Italian Hospital: Antibiotic Resistance and Genotypic Characterization of the Endemic Strain

An alarming increase of vancomycin-resistant Enterococcus faecium (VREfm) isolates was detected in an Italian referral hospital subjected to policies of infection control validated by the Joint Commission International. Analysis of the population structure of 122 consecutive, nonreplicate VREfm isolates collected over an 18-month period identified a single major clone that spread around the whole hospital, rapidly establishing an endemic state. It belonged to sequence type (ST) 17 and showed a highly multidrug-resistant phenotype, being resistant to all antimicrobial classes for the carriage of several resistance determinants. Furthermore, some strains with decreased susceptibility to daptomycin were detected. Eighteen out of the 122 isolates did not group in the major clone. They showed a low spreading potential inside the hospital wards, even if most of them displayed a multidrug-resistant phenotype and belonged to a hospital-adapted lineage. Causes that led to the VREfm endemic state have not been fully elucidated. However, it is conceivable that the increase in systemic antibiotic consumption and the use of selective digestive tract decontamination, including vancomycin in critically ill patients during the period before 2014, may have played a role in the ST17 clone dissemination, but additional traits conferring high fitness in hospital environment cannot be excluded.