Outcome of cephalosporin treatment for serious infections due to apparently susceptible organisms producing extended-spectrum beta-lactamases: implications for the clinical microbiology laboratory

Risk Factors for and Clinical Outcomes of Bloodstream Infections Caused by Extended-Spectrum Beta-Lactamase-ProducingKlebsiella pneumoniae

Objective:

To evaluate risk factors and treatment outcomes of bloodstream infections caused by extended-spectrum beta-lactamase-producingKlebsiella pneumoniae(ESBL-KP).

Design:

Retrospective case-control study. Stored blood isolates ofK. pneumoniaewere tested for ESBL production by NCCLS guidelines, double-disk synergy test, or both.

Setting:

A 1,500-bed, tertiary-care university hospital and referral center.

Patients:

Sixty case-patients with bacteremia due to ESBL-KP were compared with 60 matched control-patients with non-ESBL-KP.

Results:

There were no significant differences in age, gender, APACHE II score, or underlying diseases between the groups. Independent risk factors for infections caused by ESBL-KP were urinary catheterization, invasive procedure within the previous 72 hours, and an increasing number of antibiotics administered within the previous 30 days. Complete response rate, evaluated 72 hours after initial antimicrobial therapy, was higher among control-patients (13.3% vs 36.7%;P= .003). Treatment failure rate was higher among case-patients (35.0% vs 15%;P= .011). Overall 30-day mortality rate was 30% for case-patients and 28.3% for control-patients (P= .841). Case-patients who received imipenem or ciprofloxacin as a definitive antibiotic had 10.5% mortality. The mortality rate for initially ineffective therapy was no higher than that for initially effective therapy (9.1% vs 11.1%;P= 1.000), but statistical power was low for evaluating mortality in the absence of septic shock.

Conclusion:

ForK. pneumoniaebacteremia, patients with ESBL-KP had a higher initial treatment failure rate but did not have higher mortality if antimicrobial therapy was appropriately adjusted in this study with limited statistical power.

Prospective Evaluation of Colonization with Extended-Spectrum β-Lactamase (ESBL)–Producing Enterobacteriaceae Among Patients at Hospital Admission and of Subsequent Colonization with ESBL-Producing Enterobacteriaceae Among Patients During Hospitalization

Objective.

To determine the rates of and risk factors for carriage and acquisition of extended-spectrum (β-lactamase (ESBL)-producing Enterobacteriaceae during hospitalization.

Design.

Cohort study.

Setting.

Shaare Zedek Medical Center, a 550-bed teaching hospital.

Methods.

During a 5-month period (February 1-June 30, 2004), 167 (8%) of 1,985 newly admitted general medical patients were enrolled in our study. Nasal, oropharyngeal, and rectal swab specimens were obtained at admission and every 2-3 days until hospital discharge or death. Enterobacteriaceae isolates were tested for ESBL, andStaphylococcus aureusisolates were tested for methicillin resistance.

Results.

Of the 167 patients enrolled in our study, 15 (9%) were identified as nasal carriers of methicillin-resistantS. aureus(MRSA) at admission, and 13 (8%) were rectal carriers of ESBL-producing Enterobacteriaceae at admission. Univariate risk factors for rectal carriage of ESBL-producing Enterobacteriaceae included female sex (odds ratio [OR], 11 [95% confidence interval {CI}, 1.4—238];P< .05), nursing home residence (OR, 6.9 [95% CI, 1.8-27];P< .01), recent antibiotic treatment (OR, 9.8 [95% CI, 1.7-74];P< .05), and concomitant nasal carriage of MRSA and/or ESBL-producing Enterobacteriaceae (OR, 5.8 [95% CI, 1.2-26];P< .01). Multivariate risk factors were female sex and recent antibiotic treatment. During hospitalization, 35 (21%) of 167 patients had acquired rectal carriage of ESBL-producing Enterobacteriaceae (P= .002, for trend analysis). Of the 12 patients who were still in the hospital 2 weeks after admission, 4 (33%) were carriers of ESBL-producing Enterobacteriaceae. Univariate risk factors for acquisition included an age of older than 65 years (P< .005), nursing home residence (OR 2.6, [95% CI, 0.98-2.6]), impaired cognition (OR, 4.8 [95% CI, 1.9-12]), recent antibiotic treatment (OR, 2.7 [95% CI, 0.9-8.3]), respiratory assistance (OR, 4.2 [95% CI, 1.2-14]), and prolonged hospitalization. Multivariate risk factors were an age of older than 65 years and broad-spectrum antibiotic therapy.

Conclusions.

Rectal carriage of ESBL-producing Enterobacteriaceae occurred in 13 (8%) of 167 patients at admission to the medical departments of our hospital and in 4 (33%) of 12 patients still remaining in our hospital after 2 weeks.

Population Pharmacokinetics of Cefazolin in Serum and Tissue for Patients with Complicated Skin and Soft Tissue Infections (cSSTI)

Introduction

Cefazolin is commonly used to treat complicated skin and soft tissue infections (cSSTI) caused by methicillin-susceptible Staphylococcus aureus (MSSA) and Enterobacteriaceae. We aimed to determine the variability of cefazolin exposure in interstitial fluid (ISF) of tissue and evaluate its dosing recommendations.

Methods

Population pharmacokinetics were performed to co-model serum and ISF concentration data from six patients enrolled in a previous in vivo microdialysis study. A 5,000 patient Monte Carlo simulation was then conducted for 1 and 2 g every 8 h (q8h) regimens to calculate the penetration ratio and probability of target attainment (PTA) at 30% and 50% of the dosing interval that free drug concentrations remain above the minimum inhibitory concentration (fT > MIC) in ISF of tissue.

Results

A three-compartment model, with one of the compartments representing ISF concentrations, fits the data best. The final model resulted in the mean ± SD parameter values: Clearance = 3.8 ± 2.1 L/h, volume of distribution in central compartment = 8.6 ± 6.4 L and volume of distribution in ISF = 36.6 ± 17.9 L. The mean ± SD and median penetration ratios were 1.36 ± 4.57 and 0.80, respectively. At the MIC₉₀ for MSSA of 1 mg/L, PTAs for the 1 g q8h dose in ISF were 96% and 91% for 30% and 50% fT > MIC targets, respectively, which decreased to 87% and 71% at 2 mg/L. For the same respective targets, a 2 g q8h dosing regimen increased PTA to 96% and 91% at 2 mg/L.

Conclusion

Cefazolin penetration into the ISF of a lower limb infection varied across this simulated patient population. Based on these data, a 1 g q8h regimen should be sufficient to obtain 30% fT > MIC exposure against most MSSA causing cSSTI. However, a 2 g q8h dose is required to obtain 50% fT > MIC pharmacodynamic targets at the current breakpoint for Enterobacteriaceae (2 mg/L).

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0049-3) contains supplementary material, which is available to authorized users.

Prevalence of Extended Spectrum β-lactamase-Producing Klebsiella pneumoniae in Clinical Isolates

Background:

Extended spectrum β-lactamase (ESBL) are gram-negative bacteria that produce the enzyme, β-lactamase, which can break down commonly used antibiotics, such as penicillin and cephalosporins, making infections with ESBL producing bacteria more difficult to treat. Extended spectrum β-lactamase-producing Klebsiella pneumoniae were first reported in 1983 from Germany, and since then a steady increase in resistance against cephalosporins has been seen causing health problems.

Objectives:

The aim of this study was to determine the prevalence of ESBL in strains of K. pneumoniae isolated from different clinical samples.

Patients and Methods:

One hundred and thirty isolates of K. pneumoniae were isolated from different clinical specimens from King Khalid hospital, Hafr Elbatin, Kingdom Saudi Arabia. These isolates were then characterized, tested for antimicrobial susceptibility and screened for ESBL production by the MicroScan WalkAway-96 SI System. Extended spectrum β-lactamase production was confirmed by the phenotypic confirmatory disc diffusion test (PCDDT) and the double disc synergy test (DDST).

Results:

Overall, 76.9% (100) of the isolates were resistant to cefuroxime, cefepime and cefazolin, 69.23% (90) were resistant to cefotaxime, and 46.15% (60) were resistant to cefoxitin. Extended spectrum β-lactamase was detected in 53.8% (70) of K. pneumoniae as detected by the MicroScan “WalkAway-96” SI System and 50.07% (66) by PCDDT and 46.15% (60) by DDST. All K. pneumoniae isolates were resistant to ampicillin followed by both piperacillin and mezlocillin 92.30% (120). K.pneumoniae isolates showed high sensitivity to imipenem (15.38%) (20), followed by ertapenem, tetracycline, tigecycline pipracilline/tazobactam and amikacin (23.07%) (30).

Conclusions:

Our study showed that the prevalence of ESBL-producing K. pneumoniae at King Khalid Hospital was significantly high. Routine detection of ESBL-producing microorganisms is required by each of the laboratory standard detection methods to control the spread of these infections and allow a proper therapeutic strategy. For detection, the phenotypic confirmatory disc diffusion test is simple, sensitive and cost effective. However, there is a need for larger scale drug susceptibility surveillance.

Beyond Susceptible and Resistant, Part II: Treatment of Infections Due to Gram-Negative Organisms Producing Extended-Spectrum β-Lactamases

The production of β-lactamase is the most common mechanism of resistance to β-lactam antibiotics among gram-negative bacteria. Extended-spectrum β-lactamases (ESBLs) are capable of hydrolyzing most penicillins, extended-spectrum cephalosporins, and aztreonam, but their activity is suppressed in the presence of a β-lactamase inhibitor. Serious infections with ESBL-producing isolates are associated with high rates of mortality, making early detection and adequate medical management essential to ensure optimal patient outcomes. Much controversy has centered on the recommendations for testing and reporting of antibiotic susceptibility of potential ESBL-producing organisms. The latest version of the Clinical Laboratory Standards Institute (CLSI) susceptibility reporting guidelines, published in 2010, no longer advocates for phenotypic testing of ESBL-producing isolates. From newer studies demonstrating a correlation between organism minimum inhibitory concentration (MIC) and clinical outcome, along with pharmacokinetic/pharmacodynamic (PK/PD) modeling demonstrating the importance of the MIC to achieving therapeutic targets, the CLSI has assigned lower susceptibility breakpoints for aztreonam and most cephalosporins. The new guidelines recommend using the lower MIC breakpoints to direct antibiotic selection. This article reviews the microbiology and epidemiology of ESBLs, the recent change in CLSI susceptibility reporting guidelines for ESBLs, and the clinical and PK/PD data supporting the relationship between in vitro susceptibility and clinical outcome. Finally, considerations for antimicrobial selection when treating patients with infections caused by ESBL-producing organisms from various sources are discussed.

The inoculum effect of antibiotics against CTX-M-extended-spectrum β-lactamase-producing Escherichia coli

BACKGROUND

Questions remain regarding the use of the cephalosporins to treat infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. For example, should ceftazidime or cefepime be used to treat infections with CTX-M ESBL-producing organisms with low MICs (minimum inhibitory concentrations), according to the new Clinical and Laboratory Standards Institute's (CLSI) recommendations for susceptibility testing? Some studies have reported that in vitro MICs of cephalosporins increase as the inoculum increases, which is the inoculum effect; however, most of the enzymes studied were SHV and TEM. In this study, we aimed to investigate the inoculum effect on ceftazidime, cefepime and four other β-lactam agents against CTX-M-ESBLs-producing Escherichia coli.

METHODS

Antibiotic susceptibilities were determined using broth microdilution MIC methodology according to the CLSI recommended with standard and 100-fold-higher inocula.

RESULTS

An inoculum effect on meropenem and cefminox was not detected. The size of the inoculum affected piperacillin/tazobactam activity against only 4 strains, all CTX-M-14 genotypes. The inoculum size affected the activity of ceftazidime, cefepime and cefotaxime against 35%, 85%, 100% of strains, respectively. Among the strains with an inoculum effect, CTX-M-14 was the most common ESBL genotype.

CONCLUSIONS

These findings suggest that meropenem is the most active compound against serious infections caused by Escherichia coli producing ESBLs. Cefminox and piperacillin-tazobactam exhibit strong activity against many strains. Until further studies are performed, clinicians should be aware that third- and fourth-generation cephalosporins (such as ceftazidime and cefepime) are not reliable for serious infections even though in vitro tests indicate susceptibility.

Nosocomial extended-spectrum beta-lactamase-producing Klebsiella pneumoniae bacteremia in hemodialysis patients and the implications for antibiotic therapy

BACKGROUND

In the face of increasing treatment options for extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-Kp) hemodialysis (HD) access-related bacteremia, the difference in clinical effectiveness between ertapenem and flomoxef remains unclear. We conducted this retrospective study to determine their efficacies and treatment outcomes.

METHODS

Patients on maintenance HD with fistula-, graft-, or catheter-related ESBL-Kp bacteremia were enrolled. Data related to clinical features and antibiotic treatments were collected. Outcome was determined by mortality resulting from bacteremia during the 14-day period after the collection of the first positive blood culture for flomoxef-susceptible ESBL-Kp.

RESULTS

The 64 patients studied had severe septicemia as determined by the Pitt bacteremia score; 50% (32/64) were in the intensive care unit (ICU) at the time of bacteremia. Old age (>65 years; 57.8%), malnutrition (albumin<3.5g/dl; 92.2%), a history of severe illnesses (defined by shock, intubation, or ICU stay; 82.5%), and prolonged hospitalization prior to the onset of bacteremia (>30 days; 75%) were also highly prevalent. The study population comprised nine fistula-, 10 graft-, and 45 HD catheter-related bacteremia cases, and the mortality rate was high (38/64, 59.4%). The mortality rate was significantly higher in the flomoxef treatment group than in the ertapenem treatment group (22/30, 73% vs. 16/34, 47%, p<0.05). Among patients with catheter-related bacteremia, multivariate analyses revealed that flomoxef use (odds ratio (OR) 2.52, 95% confidence interval (CI) 1.34-35.17) and Pitt bacteremia score (OR 4.37, 95% CI 1.28-5.26) were independently associated with mortality.

CONCLUSIONS

In accordance with our previous study, our results have demonstrated the inferiority of flomoxef to carbapenems in the treatment of HD access-related ESBL-Kp bacteremia and provide an insight into the possibility of using ertapenem rather than flomoxef as an initial or de-escalating therapy for infections caused by ESBL-producing bacteria.

Clinical management of infections caused by multidrug-resistant Enterobacteriaceae

Enterobacteriaceae showing resistance to cephalosporins due to extended-spectrum β-lactamases (ESBLs) or plasmid-mediated AmpC enzymes, and those producing carbapenemases have spread worldwide during the last decades. Many of these isolates are also resistant to other first-line agents such as fluoroquinolones or aminoglycosides, leaving few available options for therapy. Thus, older drugs such as colistin and fosfomycin are being increasingly used. Infections caused by these bacteria are associated with increased morbidity and mortality compared with those caused by their susceptible counterparts. Most of the evidence supporting the present recommendations is from in vitro data, animal studies, and observational studies. While carbapenems are considered the drugs of choice for ESBL and AmpC producers, recent data suggest that certain alternatives may be suitable for some types of infections. Combined therapy seems superior to monotherapy in the treatment of invasive infections caused by carbapenemase-producing Enterobacteriaceae. Optimization of dosage according to pharmacokinetics/pharmacodynamics data is important for the treatment of infections caused by isolates with borderline minimum inhibitory concentration due to low-level resistance mechanisms. The increasing frequency and the rapid spread of multidrug resistance among the Enterobacteriaceae is a true and complex public health problem.

Antibiotic resistance and extended spectrum beta-lactamases: Types, epidemiology and treatment

Antibiotic resistance is a problem of deep scientific concern both in hospital and community settings. Rapid detection in clinical laboratories is essential for the judicious recognition of antimicrobial resistant organisms. Production of extended-spectrum β-lactamases (ESBLs) is a significant resistance-mechanism that impedes the antimicrobial treatment of infections caused by Enterobacteriaceae and is a serious threat to the currently available antibiotic armory. ESBLs are classified into several groups according to their amino acid sequence homology. Proper infection control practices and barriers are essential to prevent spread and outbreaks of ESBL producing bacteria. As bacteria have developed different strategies to counter the effects of antibiotics, the identification of the resistance mechanism may help in the discovery and design of new antimicrobial agents. The carbapenems are widely regarded as the drugs of choice for the treatment of severe infections caused by ESBL-producing Enterobacteriaceae, although comparative clinical trials are scarce. Hence, more expeditious diagnostic testing of ESBL-producing bacteria and the feasible modification of guidelines for community-onset bacteremia associated with different infections are prescribed.

Predictors of 7- and 30-day mortality in pediatric intensive care unit patients with cancer and hematologic malignancy infected with Gram-negative bacteria

Background

Infection with Gram-negative bacteria is associated with increased morbidity and mortality. The aim of this study was to evaluate the predictors of 7- and 30-day mortality in pediatric patients in an intensive care unit with cancer and/or hematologic diseases and Gram-negative bacteria infection.

Methods

Data were collected relating to all episodes of Gram-negative bacteria infection that occurred in a pediatric intensive care unit between January 2009 and December 2012, and these cases were divided into two groups: those who were deceased seven and 30 days after the date of a positive culture and those who survived the same time frames. Variables of interest included age, gender, presence of solid tumor or hematologic disease, cancer status, central venous catheter use, previous Pseudomonas aeruginosa infection, infection by multidrug resistant-Gram-negative bacteria, colonization by multidrug resistant-Gram-negative bacteria, neutropenia in the preceding seven days, neutropenia duration ≥3 days, healthcare-associated infection, length of stay before intensive care unit admission, length of intensive care unit stay >3 days, appropriate empirical antimicrobial treatment, definitive inadequate antimicrobial treatment, time to initiate adequate antibiotic therapy, appropriate antibiotic duration ≤3 days, and shock. In addition, use of antimicrobial agents, corticosteroids, chemotherapy, or radiation therapy in the previous 30 days was noted.

Results

Multivariate logistic regression analysis resulted in significant relationship between shock and both 7-day mortality (odds ratio 12.397; 95% confidence interval 1.291–119.016; p = 0.029) and 30-day mortality (odds ratio 6.174; 95% confidence interval 1.760–21.664; p = 0.004), between antibiotic duration ≤3 days and 7-day mortality (odds ratio 21.328; 95% confidence interval 2.834-160.536; p = 0.003), and between colonization by multidrug resistant-Gram-negative bacteria and 30-day mortality (odds ratio 12.002; 95% confidence interval 1.578–91.286; p = 0.016).

Conclusions

Shock was a predictor of 7- and 30-day mortality, and colonization by multidrug resistant-Gram-negative bacteria was an important risk factor for 30-day mortality.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

Significant publications on infectious diseases pharmacotherapy in 2012

PURPOSE

The most important articles pertaining to infectious diseases (ID) pharmacotherapy published in 2012, as nominated and ranked by panels of pharmacists and physicians with ID expertise, are summarized.

SUMMARY

Members of the Houston Infectious Diseases Network were asked to nominate articles on ID research published in prominent peer-reviewed journals during the period January 1-December 31, 2012, with a major impact in the field of ID pharmacotherapy. A list of 42 nominated articles on general ID-related topics and 8 articles pertaining to human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) was compiled. In a survey conducted in January 2013, members of the Society of Infectious Diseases Pharmacists (SIDP) were asked to select from the list 10 general ID articles and 1 HIV/AIDS-related article that they considered to be the most important. Of the 180 SIDP members surveyed, 100 (55%) and 44 (24%) participated in ranking the general ID and HIV/AIDS-related articles, respectively. Summaries of the highest-ranked articles in both categories are presented here.

CONCLUSION

With the volume of published ID-related research growing each year, both ID specialists and nonspecialists are challenged to stay current with the literature. Key ID-related publications in 2012 included updated recommendations on management of diabetic foot infections, articles on promising approaches to prevention and early treatment of HIV disease, and reports on developments in research on pharmacotherapies for methicillin-resistant Staphylococcus aureus bacteremia and Klebsiella pneumoniae infections.

Carbapenem-resistant Enterobacteriaceae and Acinetobacter baumannii: assessing their impact on organ transplantation

PURPOSE OF REVIEW

This review highlights the impact of carbapenem-resistant Enterobacteriaceae and carbapenem-resistant Acinetobacter baumannii on patients who have undergone organ transplantation and explores both available and potential agents to treat infections caused by these multidrug-resistant (MDR) pathogens.

RECENT FINDINGS

Few antimicrobials exist to treat carbapenem-resistant Gram-negative infections, and resistance to salvage therapies is escalating. Organ transplantation appears to be a risk factor for infections with Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae. Isolation of these MDR bacteria is increasing and may be associated with allograft failure and mortality. In the majority of cases, aminoglycosides, polymyxins, and tigecycline have been employed to treat these infections. Anecdotal successes exist but these antibiotics may be unreliable. Few novel agents are in development.

SUMMARY

Bacterial infections remain a leading cause of posttransplantation morbidity and mortality. Carbapenem resistance is a significant threat to allograft and patient survival. With few antimicrobials being developed, transplant centers may be forced to make decisions regarding surveillance, empiric antimicrobial regimens, and transplant candidacy in the setting of carriage of MDR pathogens. There is an urgent need for collaborative studies to address the clinical impact of these infections on transplantation.

Incidence of extended-spectrum-β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates that test susceptible to cephalosporins and aztreonam by the revised CLSI breakpoints

The incidence of aztreonam and cephalosporin susceptibility, determined using the revised CLSI breakpoints, for extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates was evaluated. Our analysis showed that results for aztreonam and/or ≥1 cephalosporin were reported as susceptible or intermediate for 89.2% of ESBL-producing E coli isolates (569/638 isolates) and 67.7% of ESBL-producing K. pneumoniae isolates (155/229 isolates).

Extended-spectrum-beta-lactamase producing bacteria related urinary tract infection in renal transplant recipients and effect on allograft function

Background

Urinary tract infection (UTI) is a well-recognized early complication in renal transplant recipients (RTR) and can have significant bearing on their outcome. The recent rise in incidence of extended spectrum beta lactamase (ESBL) producing bacteria causing UTI among RTR poses new and significant challenges in terms of management and outcome. Our aim is to analyze the effect of ESBL producing bacteria causing UTI in these patients and its impact on allograft function.

Methods

We reviewed the medical records of 147 RTR who were followed at a tertiary care hospital affiliated transplant center between January 2007 and May 2013 and noted five RTR who developed episodes of ESBL producing bacteria related UTI during follow up. Multiple patient characteristics including demographics, immunosuppression, recurrences, allograft function and outcome were analyzed.

Results

Five patients (3.4%) out of 147 had ESBL producing bacteria related UTI. We found all patients to be above 60 years of age, with three out of five being females, and all five patients had diabetes mellitus. We identified a total of 37 episodes of UTI among these five patients during this period. Two of these patients had elevated creatinine values during the episodes of UTI and three of them developed bacteremia. Of the five patients, four of them had a favorable outcome except for one patient who developed persistent allograft dysfunction.

Conclusion

RTR are at a higher risk for developing ESBL producing bacteria associated UTI. Early diagnosis along with appropriate and judicious use of antibiotics will ensure long term success in allograft and patient outcome.

Molecular characterization of ESBL-producing Enterobacteriaceae in northern Portugal

Extended-spectrum β-lactamases (ESBLs) prevalence was studied in the north of Portugal, among 193 clinical isolates belonging to citizens in a district in the boundaries between this country and Spain from a total of 7529 clinical strains. In the present study we recovered some members of Enterobacteriaceae family, producing ESBL enzymes, including Escherichia coli (67.9%), Klebsiella pneumoniae (30.6%), Klebsiella oxytoca (0.5%), Enterobacter aerogenes (0.5%), and Citrobacter freundii (0.5%). β -lactamases genes blaTEM, blaSHV, and blaCTX-M were screened by polymerase chain reaction (PCR) and sequencing approaches. TEM enzymes were among the most prevalent types (40.9%) followed by CTX-M (37.3%) and SHV (23.3%). Among our sample of 193 ESBL-producing strains 99.0% were resistant to the fourth-generation cephalosporin cefepime. Of the 193 isolates 81.3% presented transferable plasmids harboring bla ESBL genes. Clonal studies were performed by PCR for the enterobacterial repetitive intragenic consensus (ERIC) sequences. This study reports a high diversity of genetic patterns. Ten clusters were found for E. coli isolates and five clusters for K. pneumoniae strains by means of ERIC analysis. In conclusion, in this country, the most prevalent type is still the TEM-type, but CTX-M is growing rapidly.

Rapid, low-cost fluorescent assay of β-lactamase-derived antibiotic resistance and related antibiotic susceptibility

Antibiotic resistance (AR) is increasingly prevalent in low and middle income countries (LMICs), but the extent of the problem is poorly understood. This lack of knowledge is a critical deficiency, leaving local health authorities essentially blind to AR outbreaks and crippling their ability to provide effective treatment guidelines. The crux of the problem is the lack of microbiology laboratory capacity available in LMICs. To address this unmet need, we demonstrate a rapid and simple test of β -lactamase resistance (the most common form of AR) that uses a modified β -lactam structure decorated with two fluorophores quenched due to their close proximity. When the β -lactam core is cleaved by β -lactamase, the fluorophores dequench, allowing assay speeds of 20 min to be obtained with a simple, streamlined protocol. Furthermore, by testing in competition with antibiotics, the β -lactamase-associated antibiotic susceptibility can also be extracted. This assay can be easily implemented into standard lab work flows to provide near real-time information of β -lactamase resistance, both for epidemiological purposes as well as individualized patient care.

Molecular evaluations of extended spectrum β-lactamase producing strains of Serratia isolated from blood samples of the patients in Namazi Hospital, Shiraz, Southern Iran

BACKGROUND AND OBJECTIVE

Nowadays, the presence of extended-spectrum β-lactamases (ESBLs) producing strains in Serratia genus causes the emergence of resistance to many antibiotics. So, the lack of proper diagnosis of ESBLs strains can lead to failure in the treatment. The objective of the present study was to investigate ESBLs production in Serratia strains isolated from the clinical blood samples in Shiraz, Iran.

MATERIALS AND METHODS

In this study, 39 Serratia strains isolated from the patients referred to Namazi Hospital, during a 2 year period were tested. The antimicrobial resistance of the isolates to 21 antibiotics was evaluated using Kirby-Bauer disk diffusion method. Combination disk method was used to determine the ESBL phenotype among the isolates. PCR was performed to investigate the presence of ESBL genes of SHV, OXA and TEM types.

RESULTS

The lowest antibiotic resistance rates belonged to meropenem (7.69%) and imipenem (5.12%). Overall, positive ESBL phenotype was identified in 69% (n = 27) of the isolates, 70.37% (n = 19) for S. marcescens and 29.62% (n = 8) for S. liquefaciens. Results obtained by PCR showed that only 20.51% carried OXA gene and 15.38% carried SHV-1 gene. TEM gene was detected in none of the isolates.

CONCLUSION

This study showed a high prevalence of the emerging ESBL producing strains among clinical isolates of Serratia that could lead to an increase in antibiotic resistance. However, ESBLs genes other than those tested here may be more responsible for the emergence of ESBL phenotype among Serratia clinical isolates in our region.

Outcomes of children with enterobacteriaceae bacteremia with reduced susceptibility to ceftriaxone: do the revised breakpoints translate to improved patient outcomes?

BACKGROUND

In 2010, the Clinical and Laboratory Standards Institute (CLSI) revised and lowered the ceftriaxone minimum inhibitory concentration breakpoints for Enterobacteriaceae and removed the requisite extended spectrum β-lactamase phenotypic testing for organisms with elevated minimum inhibitory concentrations. The impact that these recommendations have on clinical outcomes of children have not been previously evaluated.

METHODS

We conducted a retrospective study to compare clinical outcomes between children treated with ceftriaxone and those treated with broader spectrum β-lactams for Enterobacteriaceae bacteremia with reduced susceptibility (minimum inhibitory concentrations 4-8 µg/mL) to ceftriaxone according to the new CLSI interpretive criteria. Mortality and microbiological relapse were evaluated using a multivariable logistic regression model.

RESULTS

There were a total of 783 unique children with Enterobacteriaceae bacteremia during the study period. Using the CLSI breakpoints before 2010, 76 children would have had clinical isolates resistant to ceftriaxone. With the revised breakpoints, 229 Enterobacteriaceae isolates would no longer be susceptible to ceftriaxone (>300% increase). Of the 136 children who met eligibility criteria, 63 children received ceftriaxone and 73 children received broader spectrum β-lactams. There was no difference in 30-day mortality (odds ratio 0.81, 95% confidence interval: 0.31-2.59) or microbiological relapse (odds ratio 0.97, 95% confidence interval: 0.36-2.66) between the groups.

CONCLUSIONS

Our findings do not support the proposed clinical benefit of more conservative CLSI breakpoints. The revised breakpoints promote increased broad-spectrum β-lactam use. The need for lowered ceftriaxone breakpoints against Enterobacteriaceae in children needs to be reevaluated in larger prospective studies.

Emerging resistance problems and future perspectives in pharmacotherapy for complicated urinary tract infections

INTRODUCTION

Urinary tract infections (UTIs) are among the most common infectious diseases and contribute to high financial burden worldwide. Administration of appropriate antibiotic therapy is the key to achieving good therapeutic outcomes. The authors review the current status of global or regional epidemiology, especially on the antimicrobial resistance and several potential agents against complicated UTIs by multidrug-resistant (MDR) pathogens.

AREAS COVERED

The authors summarized the susceptibility status on several major surveillance programs on uropathogens, focusing on Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant enterococci. Besides, the current perspectives of several potential antimicrobials against MDR uropathogens available for UTIs were also reviewed.

EXPERT OPINION

High resistance to broad-spectrum antibiotics, especially to extended-spectrum β-lactams, carbapenems, and fluoroquinolones among uropathogens emerges as a critical problem in many countries. Appropriate antimicrobial stewardship and continuous surveillance are necessary to monitor the trends of susceptibility for main pathogens. For these MDR uropathogens, polymyxin, fosfomycin, tigecycline, nitrofurantoin, linezolid, and daptomycin might be potential treatments for patients with uncomplicated and complicated UTIs in some countries, although they might not be approved by their regulation. However, more clinical evidence and more extensive meta-analyses are needed to evaluate and confirm the effectiveness of their usage in countries with a high prevalence of multidrug resistance.

Etiology, extended-spectrum β-lactamase rates and antimicrobial susceptibility of gram-negative bacilli causing intra-abdominal infections in patients in general pediatric and pediatric intensive care units--global data from the Study for Monitoring Antimicrobial Resistance Trends 2008 to 2010

BACKGROUND

Antimicrobial resistance has been increasing for several years and is often higher in intensive care units (ICUs) than in other facilities. The spread of extended-spectrum β-lactamases (ESBLs) in particular has profoundly impacted antimicrobial efficacy and usage. The Study for Monitoring Antimicrobial Resistance Trends has monitored the in vitro activity of ertapenem and several comparators against aerobic gram-negative bacteria from intra-abdominal infections (IAIs) for many years. This report summarizes susceptibility levels and epidemiology for key IAI pathogens cultured from general pediatric medical wards and pediatric ICUs globally.

METHODS

1248 gram-negative bacteria were collected from pediatric IAIs by 113 labs in 40 countries from 2008 to 2010. Susceptibility was determined by Clinical and Laboratory Standards Institute broth microdilution. Susceptibility rates (%S) were determined for species with ≥10 isolates.

RESULTS

Sixty-two percent of isolates came from general pediatric wards and 38% from pediatric ICUs. The overall ESBL-positive rate was 11.0% for Escherichia coli and 38.9% for Klebsiella pneumoniae; the ESBL-positive rate for E. coli was twice as high in ICU as non-ICU. Most study drugs inhibited >90% of ESBL-negative isolates, but only the carbapenems inhibited >90% of ESBL-positive E. coli and only imipenem inhibited >90% of ESBL-positive K. pneumoniae.

CONCLUSIONS

Amikacin, imipenem and ertapenem were the most active against gram-negative bacteria from pediatric IAIs, followed closely by the fluoroquinolones and cefepime. Other cephalosporins were often <90% active. ESBL rates were 38.9% for K. pneumoniae and 11.0% for E. coli. Therapy for pediatric IAIs should take into consideration local ESBL rates because only carbapenems inhibited most of these pathogens.

A hospital-based matched case-control study to identify clinical outcome and risk factors associated with carbapenem-resistant Klebsiella pneumoniae infection

Background

Healthcare-associated infections caused by Klebsiella pneumoniae isolates are increasing and few effective antibiotics are currently available to treat patients. We observed decreased carbapenem susceptibility among K. pneumoniae isolated from patients at a tertiary private hospital that showed a phenotype compatible with carbapenemase production although this group of enzymes was not detected in any sample. The aim of this study was to describe the epidemiology and clinical outcomes associated with carbapenem-resistant K. pneumoniae and to determine the antimicrobial resistance mechanisms.

Methods

Risk factors associated with carbapenem-resistant K. pneumoniae infections were investigated by a matched case–control study from January 2006 through August 2008. A cohort study was also performed to evaluate the association between carbapenem resistance and in-hospital mortality. Bacterial identification and antimicrobial susceptibility were determined by Vitek 2 and Etest. Carbapenemase activity was detected using spectrophotometric assays. Production of beta-lactamases and alterations in genes encoding K. pneumoniae outer membrane proteins, OmpK35 and OmpK36, were analyzed by PCR and DNA sequencing, as well as SDS-Page. Genetic relatedness of carbapenem resistant isolates was evaluated by Pulsed Field Gel Electrophoresis.

Results

Sixty patients were included (20 cases and 40 controls) in the study. Mortality was higher for patients with carbapenem-resistant K. pneumoniae infections compared with those with carbapenem-susceptible K. pneumoniae (50.0% vs 25.7%). The length of central venous catheter use was independently associated with carbapenem resistance in the multivariable analysis. All strains, except one, carried bla_CTX-M-2, an extended-spectrum betalactamase gene. In addition, a single isolate also possessed bla_GES-1. Genes encoding plasmid-mediated AmpC beta-lactamases or carbapenemases (KPC, metallo-betalactamases or OXA-carbapenemases) were not detected.

Conclusions

The K. pneumoniae multidrug-resistant organisms were associated with significant mortality. The mechanisms associated with decreased K. pneumoniae carbapenem susceptibility were likely due to the presence of cephalosporinases coupled with porin alterations, which resulted from the presence of the insertion sequences in the outer membrane encoding genes.

Extended-spectrum cephalosporin-resistant Gram-negative organisms in livestock: an emerging problem for human health?

Escherichia coli, Salmonella spp. and Acinetobacter spp. are important human pathogens. Serious infections due to these organisms are usually treated with extended-spectrum cephalosporins (ESCs). However, in the past two decades we have faced a rapid increasing of infections and colonization caused by ESC-resistant (ESC-R) isolates due to production of extended-spectrum-β-lactamases (ESBLs), plasmid-mediated AmpCs (pAmpCs) and/or carbapenemase enzymes. This situation limits drastically our therapeutic armamentarium and puts under peril the human health. Animals are considered as potential reservoirs of multidrug-resistant (MDR) Gram-negative organisms. The massive and indiscriminate use of antibiotics in veterinary medicine has contributed to the selection of ESC-R E. coli, ESC-R Salmonella spp. and, to less extent, MDR Acinetobacter spp. among animals, food, and environment. This complex scenario is responsible for the expansion of these MDR organisms which may have life-threatening clinical significance. Nowadays, the prevalence of food-producing animals carrying ESC-R E. coli and ESC-R Salmonella (especially those producing CTX-M-type ESBLs and the CMY-2 pAmpC) has reached worryingly high values. More recently, the appearance of carbapenem-resistant isolates (i.e., VIM-1-producing Enterobacteriaceae and NDM-1 or OXA-23-producing Acinetobacter spp.) in livestock has even drawn greater concerns. In this review, we describe the aspects related to the spread of the above MDR organisms among pigs, cattle, and poultry, focusing on epidemiology, molecular mechanisms of resistance, impact of antibiotic use, and strategies to contain the overall problem. The link and the impact of ESC-R organisms of livestock origin for the human scenario are also discussed.

Modified Double Disc Synergy Test to Detect ESBL Production in Urinary Isolates of Escherichia coli and Klebsiella pneumoniae

BACKGROUND AND OBJECTIVES

Various phenotypic methods are recommended in the routine practice to detect the ESBL production in gram negative bacilli. Among them, the Double Disc Synergy Test (DDST) which uses the third generation cephalosporins (3GC), is a simple and a reliable method. But the coexistence of AmpC may give false negative results. In such cases, the ESBL detection can be improved by using cefepime along with the third generation cephalosporins in DDST.

METHODS

A total of 350 urinary isolates (224 Escherichia coli and 126 Klebsiella pneumoniae) were studied for ESBL production by the modified double disc test (MDDST) i.e. by using cefotaxime, ceftriaxone, cefpopdoxime (third generation cephalosporins) and cefepime ( fourth generation cephalosporin) along with a amoxicillin-clavulanate disc.

RESULTS AND INTERPRETATION

ESBL production was seen in 63.4% (142/224) Escherichia coli and in 60.3% (76/126) Klebsiella pneumoniae isolates by MDDST. Among these, in twelve E.coli and five K.pneumoniae strains, only cefepime but none of the third generation cephalosporins showed synergism with amoxicillin-clavulanate. All these seventeen strains showed a clear extension of the edge of inhibition which was produced by cefepime towards the amoxicillin-clavulanate disc. These strains were further tested for AmpC co-production by the AmpC disc test and all these strains were found to be AmpC positive, thus revealing the superior activity of cefepime in detecting ESBLs in the bacteria which co-produced AmpC. A high degree of coresistance was found in the ESBL producers.

CONCLUSION

The ESBL detection can be improved by MDDST by using cefepime along with the third generation cephalosporins.

Background and rationale for revised clinical and laboratory standards institute interpretive criteria (Breakpoints) for Enterobacteriaceae and Pseudomonas aeruginosa: I. Cephalosporins and Aztreonam

Widespread resistance in Enterobacteriaceae and Pseudomonas aeruginosa to cephalosporin and monobactam antibiotics due to extended-spectrum β-lactamases (ESBLs) has resulted in the need for reassessment of the interpretative criteria (breakpoints) established for these agents more than 2 decades ago. Following extensive evaluation, the Clinical and Laboratory Standards Institute recently adopted and published new breakpoints for these agents for use in clinical laboratories and provided updated recommendations for use of the ESBL screening test. This paper summarizes the background and supportive rationale for new interpretative criteria for cephalosporins and aztreonam for testing Enterobacteriaceae.

Evaluation and Management of Bacterial and Fungal Infections Occurring in Patients with a Hematological Malignancy: A 2011 Update

Patients with a hematological malignancy are a heterogeneous patient population who are afflicted with diseases that range from rapidly fatal acute leukemia to indolent lymphoma or chronic leukemia. Treatment options for these patients range from observation to hematopoietic stem cell transplantation (HSCT), but all patients are more susceptible to infection. The problem of infection is dynamic with continued shifts in pathogenic organisms and microbial susceptibilities, new treatment regimens that further diminish immune function, and patients receiving treatment who are now older and frailer. The classic patterns of immunodeficiency for patients with a hematological malignancy include: periods of profound neutropenia, increased iatrogenic risks (i.e., central vascular catheters), and cellular immune suppression that affects HSCT recipients, patients with lymphoid malignancies, and those receiving treatment with corticosteroids or agents like alemtuzumab [1–4]. Recent advances in antimicrobial drug development, new technology, clinical trial results, and further clinical experience have enhanced the database on which to make infection prophylaxis and treatment decisions. However, the practicing clinician must remember that the majority of basic infection management principles for patients who are neutropenic remain unchanged.

Clonal diversity of ESBL-producing Escherichia coli in pigs at slaughter level in Portugal

We aimed to determine the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in fecal samples of healthy pigs, and to evaluate their clonality and associated resistance. Forty-nine percent of pigs sampled (n=35/71) in a slaughterhouse in Portugal revealed ESBL-producing E. coli isolates. Most isolates produced CTX-M-1 enzyme (71.4%; n=25/35), followed by CTX-M-9 (11.4%; n=4/35), CTX-M-14 (5.7%; n=2/35), SHV-12 (5.7%; n=2/35), and CTX-M-32 (5.7%; n=2/35). Ninety-four percent of the isolates presented a phenotype of multi-resistance. Most isolates belonged to phylogroups B1 (42.8%; n=15/35) and A (40%; n=14/35). Multilocus sequence typing (MLST) analysis revealed nine sequence types (STs) under six clonal complexes (CCs) and nine singletons, including overrepresentation of CC10 and three new STs (ST2524, ST2525, ST2528). We observed the frequent presence of CTX-M-producing E. coli in pigs at slaughter level, most of them belonging to CC10, commonly recovered from clinical samples.

Cefepime therapy for monomicrobial bacteremia caused by cefepime-susceptible extended-spectrum beta-lactamase-producing Enterobacteriaceae: MIC matters

BACKGROUND

Extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae isolates are important clinical pathogens. In addition, the efficacy of cefepime for such infections is controversial.

METHODS

We performed a retrospective study of monomicrobial bacteremia caused by ESBL producers at 2 medical centers between May 2002 and August 2007. The patients definitively treated with in vitro active cefepime (cases) were compared with those treated with a carbapenem (controls) in a propensity score-matched analysis to assess therapeutic effectiveness. The 30-day crude mortality is the primary endpoint.

RESULTS

A total of 178 patients were eligible for the study. Patients who received cefepime (n = 17) as definitive therapy were more likely to have a clinical failure (odds ratio [OR] 6.2; 95% confidence interval [CI], 1.7-22.5; P = .002), microbiological failure (OR 5.5; 95% CI, 1.3-25.6; P = .04), and 30-day mortality (OR 7.1; 95% CI, 2.5-20.3; P < .001) than those who received carbapenem therapy (n = 161). Multivariate regression revealed that a critical illness with a Pitt bacteremia score ≥ 4 points (OR 5.4; 95% CI, 1.4-20.9; P = .016), a rapidly fatal underlying disease (OR 4.4; 95% CI, 1.5-12.6; P = .006), and definitive cefepime therapy (OR 9.9; 95% CI, 2.8-31.9; P < .001) were independently associated with 30-day crude mortality. There were 17 case-control pairs in the propensity scores matched analysis. The survival analysis consistently found that individuals who received cefepime therapy had a lower survival rate (log-rank test, P = .016).

CONCLUSIONS

Based on the current Clinical and Laboratory Standards Institute susceptible breakpoint of cefepime (minimum inhibitory concentration ≤ 8 μg/mL), cefepime definitive therapy is inferior to carbapenem therapy in treating patients with so-called cefepime-susceptible ESBL-producer bacteremia.

Antimicrobial resistance in internal medicine wards

Antimicrobial resistance is a global medical problem, affecting most bacterial pathogens. The major challenges are currently posed by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Enterobacteriaceae producing extended-spectrum-beta-lactamases (ESBL) and carbapenemases, and multi-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii. Therapeutic options are very limited and, in some cases, virtually unavailable. This article provides an overview of the recent epidemiological trends exhibited by the most important multi-resistant pathogens, and of the treatment options that are currently available for these infections.

Discrepancy between effects of carbapenems and flomoxef in treating nosocomial hemodialysis access-related bacteremia secondary to extended spectrum beta-lactamase producing Klebsiella pneumoniae in patients on maintenance hemodialysis

Background

Hemodialysis (HD) patients are susceptible to extended spectrum beta-lactamase (ESBL)-producing bacterial infections. Because the optimal treatment and clinical significance of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) HD access-related bacteremia remain unclear, we conducted this retrospective study to determine the clinical outcomes of patients treated with either flomoxef or a carbapenem.

Methods

The eligibility criterion was fistula or graft- or catheter- related ESBL-Kp bacteremia in patients on maintenance HD. The clinical characteristics and antibiotic management were analyzed. Outcome was determined by mortality resulting from bacteremia during the 14‐day period after the first positive blood culture for flomoxef-susceptible ESBL-Kp.

Results

The 57 patients studied were predominantly elderly, malnourished, with a history of severe illnesses and broad-spectrum antibiotic use before the onset of bacteremia, and with severe septicemia as determined by the Pitt bacteremia score (PBS). The study population comprised 7 fistula, 8 graft, and 42 HD catheter-related bacteremia (CRB) cases, and the mortality rate was high (36/57, 63.2%) in these 57 patients. Of 42 patients with CRB, those in the deceased group (27/42, 64.3%) had significantly lower levels of serum albumin, longer prior hospital stay and duration of catheter-dependent HD, and higher PBS than patients in the survived group. Failure to receive effective antibiotics (flomoxef or a carbapenem) within 5 days after onset of bacteremia and treatment with flomoxef both significantly contributed to higher mortality. Multivariate analyses revealed that flomoxef use, PBS, and catheter-dependent HD >30 days were independently associated with increased mortality (OR, 3.52; 95% CI, 1.19–58.17, OR, 2.92; 95% CI, 1.36–6.26 and OR, 5.73; 95% CI, 1.21–63.2, respectively).

Conclusions

Considering the high mortality rate, ESBL-Kp should be recognized as a possible pathogen in patients on maintenance HD at high risk of acquiring HD access infections associated with ESBL-producing bacteria. Carbapenems rather than flomoxef should be the therapy of choice in these critically vulnerable patients.

Ceftazidime for respiratory infections

INTRODUCTION

Ceftazidime is a third-generation cephalosporin that has activity against Gram-negative bacilli, including Pseudomonas aeruginosa. The increasing prevalence of antimicrobial resistance and the limited number of antimicrobial agents in development have necessitated a review of the current status of treatments involving ceftazidime.

AREAS COVERED

This review focuses on studies examining the in vitro antibacterial activity of ceftazidime against recent clinical isolates and recent randomized controlled trials studying the clinical efficacy of ceftazidime, and discusses strategies for the optimal use of ceftazidime for treating respiratory tract infections, mainly hospital-acquired pneumonia (HAP).

EXPERT OPINION

Although ceftazidime remains an important option for HAP treatment, its role as an effective antimicrobial agent has been compromised by the sharp increase in resistance rates over the last decade, especially in P. aeruginosa and Acinetobacter baumannii. To maintain or improve the clinical use of ceftazidime in patients with severe HAP, it will be essential to gain a thorough understanding of local resistance patterns, reserve ceftazidime use when pathogens are susceptible to other third-generation cephalosporins, optimize ceftazidime therapy using prolonged or continuous infusion, determine the effectiveness of the combination of ceftazidime with inhibitors of broad-spectrum β-lactamases and role of combination therapy for P. aeruginosa infections, and judiciously use antimicrobial agents through individualization of antimicrobial therapy for HAP.

Antibiotic heterogeneity optimizes antimicrobial prescription and enables resistant pathogen control in the intensive care unit

BACKGROUND

Multi-drug-resistant organisms (MDRO) complicate care increasingly on the general ward and in the emergency department, operating room, and intensive care unit (ICU). Whereas barrier precautions are important in limiting transmission of MDRO between patients, few tactics have been defined that reduce the genesis of MDRO.

METHOD

Review of pertinent English-language literature.

RESULTS

Antibiotic heterogeneity practices, as part of an overall antimicrobial drug stewardship program, offer one readily deployable means to reduce selection pressure for MDRO development in the ICU. The data underpinning this approach and data derived from its use indicate that, especially in surgical ICUs, heterogeneity of antibiotic prescribing can preserve or restore microbial ecology, reduce the prevalence of MDRO and the incidence of infections caused thereby, and facilitate the implementation and effectiveness of other antibiotic-sparing tactics, such as de-escalation.

CONCLUSION

Heterogeneity of antibiotic prescribing is effective in preventing the dissemination of MDRO pathogens.