Nature of gram-negative rod antibiotic resistance during antibiotic rotation

The Effect of Antibiotic-Cycling Strategy on Antibiotic-Resistant Bacterial Infections or Colonization in Intensive Care Units: A Systematic Review and Meta-Analysis

Background

Antibiotic‐resistant bacteria, especially multidrug‐resistant strains, play a key role in impeding critical patients from survival and recovery. The effectiveness of the empiric use of antibiotics in the circling manner in intensive care units (ICUs) has not been analyzed in detail and remains controversial. Therefore, this systematic review and meta‐analysis were conducted to evaluate antibiotic‐cycling effect on the incidence of antibiotic‐resistant bacteria.

Methods

We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science for studies focusing on whether a cycling strategy of empiric use of antibiotics could curb the prevalence of antibiotic‐resistant bacteria in ICUs. The major outcomes were risk ratios (RRs) of antibiotic‐resistant infections or colonization per 1,000 patient days before and after the implementation of antibiotic cycling. A random‐effects model was adopted to estimate results in consideration of clinical heterogeneity among studies. The registration number of the meta‐analysis is CRD42018094464.

Results

Twelve studies, involving 2,261 episodes of resistant infections or colonization and 160,129 patient days, were included in the final analysis. Based on the available evidence, the antibiotic‐cycling strategy did not reduce the overall incidence of infections or colonization with resistant bacteria (RR = 0.823, 95% CI 0.655–1.035, p = .095). In subgroup analyses, the cycling strategy cut down the incidence of resistant bacteria more significantly than baseline period (p = .028) but showed no difference in comparison with mixing strategy (p = .758).

Linking Evidence to Action

Although the cycling strategy performed better than relatively free usage of antibiotics in the baseline period on reducing resistant bacteria, the cycling strategy did not show advantage when compared with the mixing strategy in subgroup analyses. In addition, these viewpoints still need more evidence to confirm.

Successful perioperative infection control measures after gastroenterological surgery reduced the number of cases of methicillin-resistant Staphylococcus aureus or Clostridioides (Clostridium) difficile infection to almost zero over a 30-year period: a single-department experience

PURPOSE

To investigate changes in the incidence of postoperative infections in the surgical department of a teaching hospital.

METHODS

During the 30-year period from September 1987 to August 2017, 11,568 gastroenterological surgical procedures were performed in our surgical department. This 30-year period was divided into seven periods (A-G), ranging from 2 to 7 years each and based on the infection control methods used in each period. We then compared the rates of incisional surgical site infection (SSI) and organ/space SSI; remote infection (RI) including respiratory tract infection (RTI), intravascular catheter-related infection, and urinary tract infection (UTI); and antibiotic-associated colitis caused by methicillin-resistant Staphylococcus aureus (MRSA) enteritis or Clostridioides (Clostridium) difficile-associated disease (CDAD) among the seven periods.

RESULTS

In periods B (September 1990-August 1997) and E (November 2004-July 2007), when a unique antibiotic therapy devised in our department was in use, MRSA was isolated from only 0.3% and 0.4% of surgical patients, respectively, and these rates were significantly lower than those in the other periods (p < 0.05). The rate of CDAD increased during period F (August 2007-July 2014), but in period G (August 2014-August 2017), restrictions were placed on the use of antibiotics with a strong anti-anaerobic action and, in this period, the rate of CDAD was only 0.04%, which was significantly lower than that in period F (p < 0.05).

CONCLUSIONS

Limiting the use of antibiotics that tend to disrupt the intestinal flora may reduce the rates of MRSA infection and CDAD after gastroenterological surgery.

Evaluation of a Mixing versus a Cycling Strategy of Antibiotic Use in Critically-Ill Medical Patients: Impact on Acquisition of Resistant Microorganisms and Clinical Outcomes

Objective

To compare the effect of two strategies of antibiotic use (mixing vs. cycling) on the acquisition of resistant microorganisms, infections and other clinical outcomes.

Methods

Prospective cohort study in an 8-bed intensive care unit during 35- months in which a mixing-cycling policy of antipseudomonal beta-lactams (meropenem, ceftazidime/piperacillin-tazobactam) and fluoroquinolones was operative. Nasopharyngeal and rectal swabs and respiratory secretions were obtained within 48h of admission and thrice weekly thereafter. Target microorganisms included methicillin-resistant S. aureus, vancomycin-resistant enterococci, third-generation cephalosporin-resistant Enterobacteriaceae and non-fermenters.

Results

A total of 409 (42%) patients were included in mixing and 560 (58%) in cycling. Exposure to ceftazidime/piperacillin-tazobactam and fluoroquinolones was significantly higher in mixing while exposure to meropenem was higher in cycling, although overall use of antipseudomonals was not significantly different (37.5/100 patient-days vs. 38.1/100 patient-days). There was a barely higher acquisition rate of microorganisms during mixing, but this difference lost its significance when the cases due to an exogenous Burkholderia cepacia outbreak were excluded (19.3% vs. 15.4%, OR 0.8, CI 0.5–1.1). Acquisition of Pseudomonas aeruginosa resistant to the intervention antibiotics or with multiple-drug resistance was similar. There were no significant differences between mixing and cycling in the proportion of patients acquiring any infection (16.6% vs. 14.5%, OR 0.9, CI 0.6–1.2), any infection due to target microorganisms (5.9% vs. 5.2%, OR 0.9, CI 0.5–1.5), length of stay (median 5 d for both groups) or mortality (13.9 vs. 14.3%, OR 1.03, CI 0.7–1.3).

Conclusions

A cycling strategy of antibiotic use with a 6-week cycle duration is similar to mixing in terms of acquisition of resistant microorganisms, infections, length of stay and mortality.

Fighting antibiotic resistance in the intensive care unit using antibiotics

Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to classical infection prevention protocols and surveillance programs, counterintuitive interventions, such as selective decontamination with antibiotics and antibiotic rotation have been applied and investigated to control the emergence of antibiotic resistance. This review provides an overview of selective oropharyngeal and digestive tract decontamination, decolonization of methicillin-resistant Staphylococcus aureus and antibiotic rotation as strategies to modulate antibiotic resistance in the intensive care unit.

Evaluation of new antimicrobials for the hospital formulary. Policies restricting antibiotic use in hospitals

In Spain, the inclusion of new antibiotics in hospital formularies is performed by the Infection Policy Committee or the Pharmacy and Therapeutic Committee, although now the decision is moving to a regional level. Criteria for the evaluation of new drugs include efficacy, safety and cost. For antimicrobial drugs evaluation it is necessary to consider local sensibility and impact in bacterial resistance to determinate the therapeutic positioning. There is compelling evidence that the use of antibiotics is associated with increasing bacterial resistance, and a great number of antibiotics are used incorrectly. In order to decrease the inappropriate use of antibiotics, several approaches have been proposed. Limiting the use of antimicrobials through formulary restrictions, often aimed at drugs with a specific resistance profile, shows benefits in improving antimicrobial susceptibilities and decreasing colonization by drug-resistant organisms. However, the restriction of one agent may result in the increased utilization of other agents. By using antibiotic cycling, the amount of antibiotics is maintained below the threshold where bacterial resistance develops, thus preserving highly efficient antibiotics. Unfortunately, cumulative evidence to date suggests that antibiotic cycling has limited efficacy in preventing antibiotic resistance. Finally, although there is still little clinical evidence available on antibiotic heterogeneity, the use of most of the existing antimicrobial classes could limit the emergence of resistance. This review summarizes information regarding antibiotic evaluation and available restrictive strategies to limit the use of antibiotics at hospitals with the aim of curtailing increasing antibiotic resistance.

Antibiotic rotation strategies to reduce antimicrobial resistance in Gram-negative bacteria in European intensive care units: study protocol for a cluster-randomized crossover controlled trial

Background

Intensive care units (ICU) are epicenters for the emergence of antibiotic-resistant Gram-negative bacteria (ARGNB) because of high rates of antibiotic usage, rapid patient turnover, immunological susceptibility of acutely ill patients, and frequent contact between healthcare workers and patients, facilitating cross-transmission.

Antibiotic stewardship programs are considered important to reduce antibiotic resistance, but the effectiveness of strategies such as, for instance, antibiotic rotation, have not been determined rigorously. Interpretation of available studies on antibiotic rotation is hampered by heterogeneity in implemented strategies and suboptimal study designs. In this cluster-randomized, crossover trial the effects of two antibiotic rotation strategies, antibiotic mixing and cycling, on the prevalence of ARGNB in ICUs are determined. Antibiotic mixing aims to create maximum antibiotic heterogeneity, and cycling aims to create maximum antibiotic homogeneity during consecutive periods.

Methods/Design

This is an open cluster-randomized crossover study of mixing and cycling of antibiotics in eight ICUs in five European countries. During cycling (9 months) third- or fourth-generation cephalosporins, piperacillin-tazobactam and carbapenems will be rotated during consecutive 6-week periods as the primary empiric treatment in patients suspected of infection caused by Gram-negative bacteria. During mixing (9 months), the same antibiotics will be rotated for each consecutive antibiotic course. Both intervention periods will be preceded by a baseline period of 4 months. ICUs will be randomized to consecutively implement either the mixing and then cycling strategy, or vice versa. The primary outcome is the ICU prevalence of ARGNB, determined through monthly point-prevalence screening of oropharynx and perineum. Secondary outcomes are rates of acquisition of ARGNB, bacteremia and appropriateness of therapy, length of stay in the ICU and ICU mortality. Results will be adjusted for intracluster correlation, and patient- and ICU-level variables of case-mix and infection-prevention measures using advanced regression modeling.

Discussion

This trial will determine the effects of antibiotic mixing and cycling on the unit-wide prevalence of ARGNB in ICUs.

Trial registration

ClinicalTrials.gov NCT01293071 December 2010.

Cycling empirical antibiotic therapy in hospitals: meta-analysis and models

The rise of resistance together with the shortage of new broad-spectrum antibiotics underlines the urgency of optimizing the use of available drugs to minimize disease burden. Theoretical studies suggest that coordinating empirical usage of antibiotics in a hospital ward can contain the spread of resistance. However, theoretical and clinical studies came to different conclusions regarding the usefulness of rotating first-line therapy (cycling). Here, we performed a quantitative pathogen-specific meta-analysis of clinical studies comparing cycling to standard practice. We searched PubMed and Google Scholar and identified 46 clinical studies addressing the effect of cycling on nosocomial infections, of which 11 met our selection criteria. We employed a method for multivariate meta-analysis using incidence rates as endpoints and find that cycling reduced the incidence rate/1000 patient days of both total infections by 4.95 [9.43–0.48] and resistant infections by 7.2 [14.00–0.44]. This positive effect was observed in most pathogens despite a large variance between individual species. Our findings remain robust in uni- and multivariate metaregressions. We used theoretical models that reflect various infections and hospital settings to compare cycling to random assignment to different drugs (mixing). We make the realistic assumption that therapy is changed when first line treatment is ineffective, which we call “adjustable cycling/mixing”. In concordance with earlier theoretical studies, we find that in strict regimens, cycling is detrimental. However, in adjustable regimens single resistance is suppressed and cycling is successful in most settings. Both a meta-regression and our theoretical model indicate that “adjustable cycling” is especially useful to suppress emergence of multiple resistance. While our model predicts that cycling periods of one month perform well, we expect that too long cycling periods are detrimental. Our results suggest that “adjustable cycling” suppresses multiple resistance and warrants further investigations that allow comparing various diseases and hospital settings.

The rise of antibiotic resistance is a major concern for public health. In hospitals, frequent usage of antibiotics leads to high resistance levels; at the same time the patients are especially vulnerable. We therefore urgently need treatment strategies that limit resistance without compromising patient care. Here, we investigate two strategies that coordinate the usage of different antibiotics in a hospital ward: “cycling”, i.e. scheduled changes in antibiotic treatment for all patients, and “mixing”, i.e. random assignment of patients to antibiotics. Previously, theoretical and clinical studies came to different conclusions regarding the usefulness of these strategies. We combine meta-analyses of clinical studies and epidemiological modeling to address this question. Our meta-analyses suggest that cycling is beneficial in reducing the total incidence rate of hospital-acquired infections as well as the incidence rate of resistant infections, and that this is most pronounced at low baseline levels of resistance. We corroborate our findings with theoretical epidemiological models. When incorporating treatment adjustment upon deterioration of a patient's condition (“adjustable cycling”), we find that our theoretical model is in excellent accordance with the clinical data. With this combined approach we present substantial evidence that adjustable cycling can be beneficial for suppressing the emergence of multiple resistance.

Antibiotic rotation for febrile neutropenic patients with hematological malignancies: clinical significance of antibiotic heterogeneity

Background

Our unit adopted the single administration of cefepime as the initial treatment for febrile episodes in neutropenic patients with hematological malignancies. However, recently, cefepime-resistant gram-negative bacteremia, including those with extended-spectrum β-lactamase (ESBL)-producers, was frequently observed in these patients. Therefore, we instituted a rotation of primary antibiotics for febrile neutropenic patients in an attempt to control antibiotic resistance.

Methods

This prospective trial was performed from August 2008 through March 2011 at our unit. After a pre-intervention period, in which cefepime was used as the initial agent for febrile neutropenia, 4 primary antibiotics, namely, piperacillin-tazobactam, ciprofloxacin, meropenem, and cefepime, were rotated at 1-month intervals over 20 months. Blood and surveillance cultures were conducted for febrile episodes, in order to assess the etiology, the resistance pattern (particularly to cefepime), and the prognosis.

Results

In this trial, 219 patients were registered. A 65.9% reduction in the use of cefepime occurred after the antibiotic rotation. In the surveillance stool cultures, the detection rate of cefepime-resistant gram-negative isolates, of which ESBL-producers were predominant, declined significantly after the intervention (8.5 vs 0.9 episodes per 1000 patient days before and after intervention respectively, P<0.01). Interestingly, ESBL-related bacteremia was not detected after the initiation of the trial (1.7 vs 0.0 episodes per 1000 patient days before and after intervention respectively, P<0.01). Infection-related mortality was comparable between the 2 periods.

Conclusions

We implemented a monthly rotation of primary antibiotics for febrile neutropenic patients. An antibiotic heterogeneity strategy, mainly performed as a cycling regimen, would be useful for controlling antimicrobial resistance among patients treated for febrile neutropenia.

A 9-Year retrospective review of antibiotic cycling in a surgical intensive care unit

BACKGROUND

Six years after initiating a monthly antibiotic cycling protocol in the surgical intensive care unit (SICU), we retrospectively reviewed antibiogram-derived sensitivities of predominant gram-negative pathogens before and after antibiotic cycling. We also examined susceptibility patterns in the medical intensive care unit (MICU) where antibiotic cycling is not practiced.

MATERIALS AND METHODS

Antibiotic cycling protocol was implemented in the SICU starting in 2003, with monthly rotation of piperacillin/tazobactam, imipenem/cilastin, and ceftazidime. SICU antibiogram data from positive clinical cultures for years 2000 and 2002 were included in the pre-cycling period, and those from 2004 to 2009 in the cycling period.

RESULTS

Profiles of SICU pseudomonal isolates before (n = 116) and after (n = 205) implementing antibiotic cycling showed statistically significant improvements in susceptibility to ceftazidime (66% versus 81%; P = 0.003) and piperacillin/tazobactam (75% versus 85%; P = 0.021), while susceptibility to imipenem remained unaltered (70% in each case; P = 0.989). Susceptibility of E. coli isolates to piperacillin/tazobactam improved significantly (46% versus 83%; P < 0.0005), trend analysis showing this improvement to persist over the study period (P = 0.025). Similar findings were not observed in the MICU. Review of 2004-2009 antibiotic prescription practices showed monthly heterogeneity in the SICU, and a 2-fold higher prescribing of piperacillin/tazobactam in the MICU (P < 0.0001).

CONCLUSIONS

Six years into antibiotic cycling, we found either steady or improved susceptibilities of clinically relevant gram-negative organisms in the SICU. How much of this effect is from cycling is unknown, but the antibiotic heterogeneity provided by this practice justifies its ongoing use.

Reduction in rates of methicillin-resistant Staphylococcus aureus infection after introduction of quarterly linezolid-vancomycin cycling in a surgical intensive care unit

BACKGROUND

The burden of infection with antibiotic-resistant gram-positive cocci, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE), continues to increase, leading to substantial morbidity and high mortality rates, particularly in intensive care units (ICUs). Creative interventions may be required to reverse or stabilize this trend.

METHODS

The efficacy of empiric cycling of antibiotics active against gram-positive organisms was tested in a before-after intervention in a single surgical ICU. Four years of baseline data were compared with two years of data compiled after the implementation of a strategy where the empiric antibiotic of choice for the treatment of gram-positive infections (linezolid or vancomycin) was changed every three months. Whatever the initial choice of drug, if possible, the antibiotic was de-escalated after final culture results were obtained. The rates of all gram-positive infections were analyzed, with a particular focus on MRSA and VRE. Concurrently, similar outcomes were followed for patients treated on the same services but outside the ICU, where cycling was not practiced.

RESULTS

During the four years prior to cycling, 543 infections with gram-positive organisms were acquired in the ICU (45.3/1,000 patient-days), including 105 caused by MRSA (8.8/1,000 patient days) and 21 by VRE (1.8/1,000 patient-days). In the two years after implementation of cycling, 169 gram-positive infections were documented (28.1/1,000 patient-days; p < 0.0001 vs. non-cycling period), including 11 caused by MRSA (1.8/1,000 patient-days; p < 0.0001 vs. non-cycling period). The percentage of S. aureus infections caused by MRSA declined from 67% to 36%. The rate of infection with VRE was unchanged. Outside the ICU, the yearly numbers of infections with both MRSA and VRE increased over time.

CONCLUSION

Quarterly cycling of linezolid and vancomycin in the ICU is a promising method to reduce infections with MRSA.

Antibiotic cycling to decrease bacterial antibiotic resistance: a 5-year experience on a bone marrow transplant unit

Multidrug-resistant pathogens have important effects on clinical outcomes. Antibiotic cycling is one approach to control anti-microbial resistance, but few studies have examined cycling in hematology-oncology units. Antibiotic cycling was implemented in January 1999 at our hematology-oncology unit, alternating piperacillin-tazobactam (pip-tazo) and cefepime in 3 months periods, until June 2004. Clinical isolates were compared in post- and pre-intervention periods and with the susceptibility among the solid organ transplant intensive care unit (TICU) isolates. The rate of Gram-negative isolates remained stable. Among Gram-negatives, susceptibility to cefepime and pip-tazo remained stable. There was an increase in Enterococcus spp. (P=0.007), and susceptibility to ampicillin and vancomycin decreased (odds ratio (OR): 0.04, 95% confidence interval (CI): 0.17-0.89 and OR: 0.23, 95% CI: 0.09-0.58). Compared with the TICU, there was increased susceptibility to pip-tazo and cefepime among enterics (OR: 7.32, 95% CI: 4.44-12.07 and OR: 8.82, 95% CI: 2.1-37.13) and Pseudomonas aeruginosa (OR: 4.27, 95% CI: 1.47-12.4 and OR: 4.61, 95% CI: 1.75-12.1) and decreased susceptibility to ampicillin and vancomycin among enterococci (OR: 0.44, 95% CI: 0.30-0.63 and OR: 0.38, 95% CI: 0.26-0.56). Cycling was associated with preserved antibiotic susceptibility among Gram-negatives, but with an increase in Enterococcus spp. and vancomycin and ampicillin resistance among enterococci.

Cost of Gram-negative resistance*

OBJECTIVE

It is unclear that infections with Gram-negative rods resistant to at least one major class of antibiotics (rGNR) have a greater effect on patient morbidity than infections caused by sensitive strains (sGNR). We wished to test the hypothesis that rGNR infections are associated with higher resource utilization.

DESIGN

Retrospective observational cohort study of prospectively collected data.

SETTING

University hospital surgical intensive care unit and ward.

PATIENTS

Surgical patients with at least one GNR infection.

MEASUREMENTS

We compared admissions treated for rGNR infection with those with sGNR infections. Primary outcomes were total hospital costs and hospital length of stay. Other outcomes included antibiotic treatment cost, in-hospital death, and intensive care unit length of stay. After univariate analysis comparing outcomes after rGNR infection with those after sGNR infection, multivariate linear regression models for hospital cost and length of stay were created to account for potential confounders.

MAIN RESULTS

Cost data were available for 604 surgical admissions treated for at least one GNR infection (Centers for Disease Control and Prevention criteria), 137 (23%) of which were rGNR infections. Admissions with rGNR infections were associated with a higher severity of illness at the time of infection (Acute Physiology and Chronic Health Evaluation II score, 17.6 +/- 0.6 vs. 13.9 +/- 0.3), had higher median hospital costs ($80,500 vs. $29,604, p < .0001) and median antibiotic costs ($2,607 vs. $758, p < .0001), and had longer median hospital length of stay (29 vs. 13 days, p < .0001) and median intensive care unit length of stay (13 days vs. 1 day, p < .0001). Infection with rGNR within the first 7 days of admission was independently predictive of increased hospital cost (incremental increase in median hospital cost estimated at $11,075; 95% confidence interval, $3,282-$20,099).

CONCLUSIONS

Early infection with rGNR is associated with a high economic burden, which is in part related to increased antibiotic utilization compared with infection with sensitive organisms. Efforts to control overuse of antibiotics should be pursued.

Effect of Antibiotic Heterogeneity on the Development of Infections with Antibiotic-resistant Gram-negative Organisms in a Non-intensive Care Unit Surgical Ward

BACKGROUND

Heterogeneous antibiotic use has been suggested to limit the emergence of resistance, but determining the optimal strategy is difficult.

METHODS

We developed a new strategy, termed "periodic antibiotic monitoring and supervision" (PAMS) program in a non-ICU surgical ward. The 2-year prospective study was divided into a 1-year observation period and a 1-year PAMS period. The use of four major classes of antibiotics in empirical therapy for Gram-negative rod (GNR) infections was supervised. During the PAMS program, recommended, restricted, and off-supervised classes of antibiotics were changed every 3 months according to the usage pattern of the antibiotics in the preceding term.

RESULTS

Cefepime (45.5%) and imipenem/cilastatin (39.4%) were the most common antibiotics of choice during the observation period. The use of these antibiotics decreased significantly during the PAMS period, and that of fluoroquinolones and extended-spectrum penicillin/beta-lactamase inhibitor increased (4.8% vs. 21.4% and 2.4% vs. 21.4%, P<0.01 respectively). Outcome analysis demonstrated a tendency toward reduction in the incidence of resistant GNR infections (P=0.079) and that of Pseudomonas aeruginosa (P=0.053). The incidence of resistant Gram-positive core infections did not decrease. Analysis of antibiotic susceptibility to GNR revealed no significant beneficial results for any antibiotics.

CONCLUSIONS

As significant changes were not observed, the PAMS program is not generally applicable and heterogeneous antibiotic use as a way of reducing infections with resistant GNR in non-ICU surgical wards was not established.