Clinical characteristics and antimicrobial patterns in complicated intra-abdominal infections: a 6-year epidemiological study in southern China

Incidence, antimicrobial resistance and mortality of Pseudomonas aeruginosa bloodstream infections among hospitalized patients in China: a retrospective observational multicenter cohort study from 2017 to 2021

Background

Pseudomonas aeruginosa (P. aeruginosa) accounts for high antimicrobial resistance and mortality rates of bloodstream infections (BSIs). We aim to investigate incidence, antimicrobial resistance and risk factors for mortality of P. aeruginosa BSIs among inpatients.

Methods

A retrospective cohort study were conducted at two tertiary hospitals in 2017-2021. Medical and laboratory records of all inpatients diagnosed with P. aeruginosa BSIs were reviewed. A generalized linear mixed model was used to identify risk factors for mortality.

Results

A total of 285 patients with P. aeruginosa BSIs were identified. Incidence of P. aeruginosa BSIs fluctuated between 2.37 and 3.51 per 100,000 patient-days over the study period. Out of 285 P. aeruginosa isolates, 97 (34.04%) were carbapenem-resistant (CR) and 75 (26.32%) were multidrug-resistant (MDR). These isolates showed low resistance to aminoglycosides (9.51-11.62%), broad-spectrum cephalosporins (17.19-17.61%), fluoroquinolones (17.25-19.43%), and polymyxin B (1.69%). The crude 30-day mortality rate was 17.89% (51/285). Healthcare costs of patients with MDR/CR isolates were significantly higher than those of patients with non-MDR/CR isolates (P < 0.001/=0.002). Inappropriate definitive therapy [adjusted odds ratio (aOR) 4.47, 95% confidence interval (95% CI) 1.35-14.77; P = 0.014], ICU stay (aOR 2.89, 95% CI: 1.26-6.63; P = 0.012) and corticosteroids use (aOR 2.89, 95% CI: 1.31-6.41; P = 0.009) were independently associated with 30-day mortality.

Conclusion

Incidence of P. aeruginosa BSIs showed an upward trend during 2017-2020 but dropped in 2021. MDR/CR P. aeruginosa BSIs are associated with higher healthcare costs. Awareness is required that patients with inappropriate definitive antimicrobial therapy, ICU stay and corticosteroids use are at higher risk of death from P. aeruginosa BSIs.

Efficacy, safety, and tolerability of antimicrobial agents for complicated intra-abdominal infection: a systematic review and network meta-analysis

BACKGROUND

Which antimicrobial agents provide the optimal efficacy, safety, and tolerability for the empirical treatment of complicated intra-abdominal infection (cIAI) remains unclear but is paramount in the context of evolving antimicrobial resistance. Therefore, updated meta-analyses on this issue are warranted.

METHODS

We systematically searched four major electronic databases from their inception through October 2022. Randomized controlled trials examining antimicrobial agents for cIAI treatment were included. Two reviewers independently assessed the quality of included studies utilizing the Cochrane Collaboration's risk of bias tool as described in the updated version 1 of the Cochrane Collaboration Handbook and extracted data from all manuscripts according to a predetermined list of topics. All meta-analyses were conducted using R software. The primary outcome was clinical success rate in patients with cIAIs.

RESULTS

Forty-five active-controlled trials with low to medium methodological quality and involving 14,267 adults with cIAIs were included in the network meta-analyses. The vast majority of patients with an acute physiology and chronic health evaluation II score < 10 had low risk of treatment failure or death. Twenty-one regimens were investigated. In the network meta-analyses, cefepime plus metronidazole was more effective than tigecycline and ceftolozane/tazobactam plus metronidazole (odds ratio [OR] = 1.96, 95% credibility interval [CrI] 1.05 ~ 3.79; OR = 3.09, 95% CrI 1.02 ~ 9.79, respectively). No statistically significant differences were found among antimicrobial agents regarding microbiological success rates. Cefepime plus metronidazole had lower risk of all-cause mortality than tigecycline (OR = 0.22, 95% CrI 0.05 ~ 0.85). Statistically significant trends were observed favoring cefotaxime plus metronidazole, which exhibited fewer discontinuations because of adverse events (AEs) when compared with eravacycline, meropenem and ceftolozane/tazobactam plus metronidazole (OR = 0.0, 95% CrI 0.0 ~ 0.8; OR = 0.0, 95% CrI 0.0 ~ 0.7; OR = 0.0, 95% CrI 0.0 ~ 0.64, respectively). Compared with tigecycline, eravacycline was associated with fewer discontinuations because of AEs (OR = 0.17, 95% CrI 0.03 ~ 0.81). Compared with meropenem, ceftazidime/avibactam plus metronidazole had a higher rate of discontinuation due to AEs (OR = 2.09, 95% CrI 1.0 ~ 4.41). In pairwise meta-analyses, compared with ceftriaxone plus metronidazole, ertapenem and moxifloxacin (one trial, OR = 1.93, 95% CI 1.06 ~ 3.50; one trial, OR = 4.24, 95% CI 1.18 ~ 15.28, respectively) were associated with significantly increased risks of serious AEs. Compared with imipenem/cilastatin, tigecycline (four trials, OR = 1.57, 95%CI 1.07 ~ 2.32) was associated with a significantly increased risk of serious AEs. According to the surface under the cumulative ranking curve, Cefepime plus metronidazole was more likely to be optimal among all treatments in terms of efficacy and safety, tigecycline was more likely to be worst regimen in terms of tolerability, and eravacycline was more likely to be best tolerated.

CONCLUSION

This study suggests that cefepime plus metronidazole is optimal for empirical treatment of patients with cIAIs and that tigecycline should be prescribed cautiously considering the safety and tolerability concerns. However, it should be noted that data currently available on the effectiveness, safety, and tolerability of antimicrobial agents pertain mostly to lower-risk patients with cIAIs.

Optimising the treatment for uncomplicated acute appendicitis (OPTIMA trial): a protocol for a multicentre, randomised, double-blinded placebo-controlled study

INTRODUCTION

Emerging evidence has shown that an antibiotic first strategy is a viable treatment option for uncomplicated acute appendicitis (AA). Although there has recently been an interest and increase in the use of antibiotics as the primary strategy for treating uncomplicated AA, there is no consensus regarding the optimum antibiotic regimen. In particular, the long-term outcomes of different antibiotic regimens, such as the recurrence rate, still lack evidence. Given that the flora of the appendix is mainly anaerobic bacteria, we hypothesised that antianaerobe regimens could decrease the recurrence rate compared with those that did not include antianaerobic antibiotics.

METHODS AND ANALYSIS

The OPTIMA(Optimising the treatment for uncomplicated acute appendicitis) trial is a multicentre, double-blinded placebo-controlled superiority randomised study aimed to evaluate the role of antianaerobic antibiotics in the resolution of uncomplicated AA. Patients (18-65 years) with uncomplicated AA (without gangrenous, perforated appendicitis, appendiceal abscess, or appendiceal fecaliths) are eligible for inclusion. The primary endpoint of this study is the success rate of the treatment, defined as the resolution of AA resulting in discharge from the hospital without surgical intervention and recurrent symptoms within one year. Secondary endpoints include mortality, postintervention complications, recurrent symptoms up to one year after treatment, hospital stay, sick leave, treatment cost, pain symptom scores and quality of life. Data are reported as the number of cases (%), median (range) and relative risk, which will be analysed using the Mann-Whitney U test or χ² test, as appropriate. P-value<0.05 will be considered significant.

ETHICS AND DISSEMINATION

The protocol has been approved by the Ethics Committee of Jinling Hospital on 13 November 2018 (2018NZKY-027-01). The trial findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR1800018896.

Antimicrobial Lessons From a Large Observational Cohort on Intra-abdominal Infections in Intensive Care Units

Severe intra-abdominal infection commonly requires intensive care. Mortality is high and is mainly determined by disease-specific characteristics, i.e. setting of infection onset, anatomical barrier disruption, and severity of disease expression. Recent observations revealed that antimicrobial resistance appears equally common in community-acquired and late-onset hospital-acquired infection. This challenges basic principles in anti-infective therapy guidelines, including the paradigm that pathogens involved in community-acquired infection are covered by standard empiric antimicrobial regimens, and second, the concept of nosocomial acquisition as the main driver for resistance involvement. In this study, we report on resistance profiles of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis and Enterococcus faecium in distinct European geographic regions based on an observational cohort study on intra-abdominal infections in intensive care unit (ICU) patients. Resistance against aminopenicillins, fluoroquinolones, and third-generation cephalosporins in E. coli, K. pneumoniae and P. aeruginosa is problematic, as is carbapenem-resistance in the latter pathogen. For E. coli and K. pneumoniae, resistance is mainly an issue in Central Europe, Eastern and South-East Europe, and Southern Europe, while resistance in P. aeruginosa is additionally problematic in Western Europe. Vancomycin-resistance in E. faecalis is of lesser concern but requires vigilance in E. faecium in Central and Eastern and South-East Europe. In the subcohort of patients with secondary peritonitis presenting with either sepsis or septic shock, the appropriateness of empiric antimicrobial therapy was not associated with mortality. In contrast, failure of source control was strongly associated with mortality. The relevance of these new insights for future recommendations regarding empiric antimicrobial therapy in intra-abdominal infections is discussed.

Pharmacokinetics of Linezolid Dose Adjustment for Creatinine Clearance in Critically Ill Patients: A Multicenter, Prospective, Open-Label, Observational Study

Purpose

The aim of this study is to use a population pharmacokinetic (PK) approach to evaluate the optimal dosing strategy for linezolid (LNZ) in critically ill patients.

Methods

This multicenter, prospective, open-label, observational study was conducted in 152 patients, and 117 of them were included in the PK model, whereas the rest were in the validation group. The percentage of therapeutic target attainment (PTTA) comprising two pharmacodynamic indices and one toxicity index was used to evaluate dosing regimens based on Monte Carlo simulations stratified by low, normal, and high renal clearance for MICs of 0.25–4 mg/L.

Results

A single-compartment model with a covariate creatinine clearance (CrCL) was chosen as the final model. The PK parameter estimates were clearance of 5.60 L/h, with CrCL adjustment factor of 0.386, and a distribution volume of 43.4 L. For MIC ≤2 mg/L, the standard dosing regimen (600 mg q12h) for patients with severe renal impairment (CrCL, 40 mL/min) and standard dosing or 900 mg q12h for patients with normal renal functions (CrCL, 80 mL/min) could achieve PTTA ≥74%. The dose of 2400 mg per 24-h continuous infusion was ideal for augmented renal clearance (ARC) with MIC ≤1 mg/L. For MICs >2 mg/L, rare optimal dose regimens were found regardless of renal function.

Conclusion

In critically ill patients, the standard dose of 600 mg q12h was sufficient for MIC ≤2 mg/L in patients without ARC. Moreover, a 2400 mg/day 24-h continuous infusion was recommended for ARC patients.

Clinical and Microbiological Characteristics of Patients with Complicated Intra-abdominal Infections in Intensive Care Unit

In order to investigate the clinical and microbiological characteristics of patients with complicated intra-abdominal infections (cIAIs) in intensive care unit (ICU), the clinical data of 612 cIAIs patients from January 2016 to December 2018 were retrospectively collected. Clinical characteristics, distribution of pathogens and drug resistance were statistically analyzed. It was found that patients with community-acquired intra-abdominal infections (CA-IAIs) made up a majority of cIAIs patients. The positive rate of abdominal drainage fluid culture was 55.56%. Gramnegative bacteria accounted for the majority, the most commonly isolated bacteria of which were Escherichia coli (20.96%), Klebsiella pneumoniae (10.20%) and Pseudomonas aeruginosa (5.57%). The most commonly isolated gram-positive bacteria were Enterococcus (16.88%) and Methicillin-resistant staphylococcus aureus (MRSA, 3.90%). Enterobacter isolates showed high resistance rate to most cephalosporins and low resistance rate to piperacillin/tazobactam and carbapenems. Extended spectrum beta-lactamase (ESBL) screen positive isolates from CA-IAIs patients showed an increasing trend in past three years. Enterococcus and MRSA showed high resistance rate to clindamycin, quinolone, erythromycin and tetracycline, while they showed high sensitivity rate to linezolid, tegacycline, teicoplanin and vancomycin. Our results indicate that isolated bacteria from abdominal drainage fluid show high resistance rates to commonly used antibiotics in ICU patients with cIAIs. The curative effects on diseases should be monitored continuously when antibiotics are used. Meanwhile, we should always keep eyes on drug-resistant bacteria, especially when the treatment efficacy is not good.

Cefoperazone-sulbactam and risk of coagulation disorders or bleeding: a retrospective cohort study

Objectives: Limited evidence has suggested that cefoperazone-sulbactam causes coagulation disorders and bleeding.Methods: The authors conducted a retrospective study to compare patients receiving cefoperazone-sulbactam versus those treated with cefoperazone-tazobactam or ceftazidime. Propensity-score matching was used to explore whether treatment with cefoperazone-sulbactam increased the risk of prothrombin time (PT) prolongation, coagulation disorders, and bleeding, or decreased platelets (PLT).Results: The cohort included 23,242 patients. Among patients receiving cefoperazone-sulbactam, the risk of PT prolongation, coagulation disorders, decreased PLT, and bleeding was 5.3%, 9.2%, 15.7%, and 4.2%, respectively. Propensity-score matching analyses suggested that cefoperazone-sulbactam increased the risk of PT prolongation (aOR 2.26, 95% CI 1.61-3.18), coagulation disorders (aOR 1.81, 95% CI 1.43-2.30), and decreased PLT (aOR 1.46, 95% CI 1.25-1.72), but not increase bleeding (aOR 1.05, 95% CI 0.79-1.40) compared with ceftazidime. Patients receiving cefoperazone-sulbactam had higher risk of PT prolongation (aOR 1.53, 95% CI 1.11-2.10), coagulation disorders (aOR 1.53, 95% CI 1.21-1.95), but not decreased PLT (aOR 0.93, 95% CI 0.81-1.07) or bleeding (aOR 1.11, 95% CI 0.87-1.42), compared with those receiving cefoperazone-tazobactam.Conclusion: Cefoperazone-sulbactam may be associated with a higher risk of PT prolongation and coagulation disorders compared with cefoperazone-tazobactam and ceftazidime.

Susceptibility breakpoint for Danofloxacin against swine Escherichia coli

Background

Improper use of antimicrobials results in poor treatment and severe bacterial resistance. Breakpoints are routinely used in the clinical laboratory setting to guide clinical decision making. Therefore, the objective of this study was to establish antimicrobial susceptibility breakpoints for danofloxacin against Escherichia coli (E.coli), which is an important pathogen of digestive tract infections.

Results

The minimum inhibitory concentrations (MICs) of 1233 E. coli isolates were determined by the microdilution broth method in accordance with the guidelines in Clinical and Laboratory Standards Institute (CLSI) document M07-A9. The wild type (WT) distribution or epidemiologic cutoff value (ECV) was set at 8 μg/mL with statistical analysis. Plasma drug concentration data were used to establish pharmacokinetic (PK) model in swine. The in vitro time kill test in our study demonstrated that danofloxacin have concentration dependent activity against E.coli. The PK data indicated that danofloxacin concentration in plasma was rapidly increased to peak levels at 0.97 h and remained detectable until 48 h after drug administration. The pharmacodynamic cutoff (CO_PD) was determined as 0.03 μg/mL using Monte Carlo simulation. To the best of our knowledge, this is the first study to establish the ECV and CO_PD of danofloxacin against E.coli with statistical method.

Conclusions

Compared to the CO_PD of danofloxacin against E.coli (0.03 μg/mL), the ECV for E.coli seemed reasonable to be used as the final breakpoint of danofloxacin against E.coli in pigs. Therefore, the ECV (MIC ≤8 μg/mL) was finally selected as the optimum danofloxacin susceptibility breakpoint for swine E.coli. In summary, this study provides a criterion for susceptibility testing and improves prudent use of danofloxacin for protecting public health.

A multicenter, double-blind, randomized, comparison study of the efficacy and safety of tigecycline to imipenem/cilastatin to treat complicated intra-abdominal infections in hospitalized subjects in China

Purpose

To assess the efficacy and safety of tigecycline in treating complicated intra-abdominal infections (cIAIs) in hospitalized patients in China.

Patients and methods

A Phase IV, multicenter, randomized, double-blinded, active-controlled, non-inferiority study was conducted. Hospitalized cIAI patients ≥18 years of age were randomized (1:1) to receive intravenous tigecycline (initial dose 100 mg, then 50 mg q12h) or imipenem/cilastatin (500 mg/500 mg or adjusted for renal dysfunction, q6h) for 5–14 days. The primary end point was clinical response for clinically evaluable (CE) subjects at test-of-cure (TOC) assessment.

Results

Four hundred and seventy subjects were randomized; 232 in the tigecycline and 231 in the imipenem/cilastatin group were treated. Tigecycline was non-inferior to imipenem/cilastatin with respect to clinical response at TOC for all CE subjects, ie, the lower bound of the two-sided 95% CI (−12.0%, −1.4%) for the treatment difference in cure rate, tigecycline (89.9%) minus imipenem/cilastatin (96.6%), was >−15%. As non-inferiority was concluded in the CE population, superiority of tigecycline over imipenem/cilastatin and superiority of imipenem/cilastatin over tigecycline were tested on the CE and the modified intent-to-treat (mITT) populations according to pre-specified statistical criteria, and neither could be demonstrated (the cure rate was 82.8% vs 88.7%, difference −6.0% [−12.8%, 0.8%], for the mITT population). The subject-level microbiological response rate at TOC for the microbiologically evaluable population was 88.0% (110/125) vs 95.3% (102/107, difference −7.3% [−15.2%, 0.5%]). Nausea, drug ineffectiveness, postoperative wound infection, vomiting, and pyrexia were the most common adverse events in tigecycline-treated subjects; pyrexia, nausea, vomiting, and increased alanine aminotransferase and aspartate aminotransferase levels were most common in imipenem/cilastatin-treated subjects; none were unanticipated.

Conclusion

Tigecycline was non-inferior to imipenem/cilastatin in treating hospitalized adult patients with cIAI. Superiority of tigecycline over imipenem/cilastatin or imipenem/cilastatin over tigecycline could not be demonstrated. Safety was consistent with the known profile for tigecycline.

ClinicalTrials.gov identifier

NCT01721408.

Microbial Spectrum of Intra-Abdominal Abscesses in Perforating Crohn's Disease: Results from a Prospective German Registry

BACKGROUND

Intra-abdominal abscesses [IAAs] are common life-threatening complications in patients with Crohn's disease [CD]. In addition to interventional drainage and surgical therapy, empirical antibiotic therapy represents a cornerstone of treatment, but contemporary data on microbial spectra and antimicrobial resistance are scarce.

METHODS

We recruited 105 patients with CD and IAAs from nine German centres for a prospective registry in order to characterize the microbiological spectrum, resistance profiles, antibiotic therapy and outcome.

RESULTS

In 92 of 105 patients, microbial investigations of abscess material revealed pathogenic microorganisms. A total of 174 pathogens were isolated, with a median of 2 pathogens per culture [range: 1-6]. Most frequently isolated pathogens were E. coli [45 patients], Streptococcus spp. [28 patients], Enterococci [27 patients], Candida [13 patients] and anaerobes [12 patients]. Resistance to third-generation cephalosporins, penicillins with beta-lactamase inhibitors and quinolones were observed in 51, 36 and 35 patients, respectively. Seven patients had multiple-drug-resistant bacteria. Thirty patients received inadequate empirical treatment, and this was more frequent in patients receiving steroids or immunosuppression [37%] than in patients without immunosuppression [10%: p = 0.001] and was associated with a longer hospital stay [21 days vs 13 days, p = 0.003].

CONCLUSION

Based on antimicrobial resistance profiles, we herein report a high rate of inadequate empirical first-line therapy for IAAs in CD, especially in patients receiving immunosuppression, and this is associated with prolonged hospitalization.

Effect of multiple drug resistance on total medical costs among patients with intra-abdominal infections in China

Background

Multiple drug resistant (MDR) intra-abdominal infections (IAIs) are associated with notable direct and societal costs. As previous studies have not considered the impact of MDR on the total medical costs (TMCs) of IAIs, the present one examines this, as well as further estimates the additional costs at a national level.

Methods

This is a retrospective study. Firstly, we randomly selected a sample of 40% of all inpatients discharged between 2014 and 2015 from a teaching hospital, due to limits in budget and the large number of patients. Then, we manually selected 254 patients with IAIs according to the International Classification of Disease, 10^th revision, using electronic medical records. Eventually, 101 patients with IAIs (64 MDR patients and 37 non-MDR patients) were included after excluding cases without laboratory test results, any pathogens detected, or antimicrobial resistant pathogens. Univariate analysis and a generalized linear model were applied to assess the parameters associated with TMCs.

Results

Compared to non-MDR patients, those with MDR pathogens were significantly associated with higher TMCs, higher antimicrobial costs, higher antimicrobial usage, larger number of pathogens, and longer length of stay and were more likely to have insurance and combination antimicrobial therapy. In addition, the average TMC among patients with MDR pathogens was ¥ 131801, which is ¥ 90201 higher than those without MDR pathogens. If our results are applied to the whole country, the sum of all attributable TMCs was ¥ 37 billion. The societal costs, furthermore, were ¥111 billion in 2015.

Conclusion

Our results provide information that should lead to increased efforts to reduce inappropriate antimicrobial therapy, in order to decrease the emergence of MDR pathogens and to reduce their economic burden.

Risk factors for Pseudomonas aeruginosa infections in Asia-Pacific and consequences of inappropriate initial antimicrobial therapy: A systematic literature review and meta-analysis

OBJECTIVES

Treating infections of Gram-negative pathogens, in particular Pseudomonas aeruginosa, is a challenge for clinicians in the Asia-Pacific region owing to inherent and acquired antimicrobial resistance. This systematic review and meta-analysis provides updated information on risk factors for P. aeruginosa infection in Asia-Pacific as well as the consequences (e.g. mortality, costs) of initial inappropriate antimicrobial therapy (IIAT).

METHODS

Embase and MEDLINE databases were searched for Asia-Pacific studies reporting the consequences of IIAT versus initial appropriate antimicrobial therapy (IAAT) in Gram-negative bacterial infections as well as risk factors for serious P. aeruginosa infection. A meta-analysis of unadjusted mortality was performed using a random-effects model.

RESULTS

A total of 22 studies reporting mortality and 13 reporting risk factors were identified. The meta-analysis demonstrated that mortality was significantly lower in patients receiving IAAT versus IIAT, with a 67% reduction observed for 28- or 30-day all-cause mortality (odds ratio=0.33, 95% confidence interval 0.20-0.55; P<0.001). Risk factors for serious P. aeruginosa infection include previous exposure to antimicrobials, mechanical ventilation and previous hospitalisation.

CONCLUSION

High rates of antimicrobial resistance in Asia-Pacific as well as the increased mortality associated with IIAT and the presence of risk factors for serious infection highlight the importance of access to newer and appropriate antimicrobials.