Antimicrobial Susceptibilities of Aerobic and Facultative Gram-Negative Bacilli from Intra-abdominal Infections in Patients from Seven Regions in China in 2012 and 2013

The efficacy and safety of eravacycline compared with current clinically common antibiotics in the treatment of adults with complicated intra-abdominal infections: A Bayesian network meta-analysis

Background

Eravacycline is a novel, fully synthetic fluorocycline antibiotic for the treatment of adults with complicated intra-abdominal infections (cIAIs). However, the efficacy and safety of eravacycline compared with current clinically common antibiotics remain unknown.

Objective

This study aims to compare the efficacy and safety of eravacycline and other clinically common antibiotics in China, including tigecycline, meropenem, ertapenem, ceftazidime/avibactam+metronidazole, piperacillin/tazobactam, imipenem/cilastatin, and ceftriaxone+metronidazole, for the treatment of adults with cIAIs and to provide a reference for clinical choice.

Methods

The PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were electronically searched to collect clinical randomized controlled studies (RCTs) comparing different antibiotics in the treatment of patients with cIAIs from inception to June 1, 2021. Two reviewers independently screened the literature, extracted data, and evaluated the risk of bias in the included studies.

Results

A total of 4050 articles were initially retrieved, and 25 RCTs were included after screening, involving eight treatment therapies and 9372 patients. The results of network meta-analysis showed that in the intention-to-treat (ITT) population, the clinically evaluable (CE) population, and the microbiologically evaluable (ME) population, the clinical response rate of eravacycline was not significantly different from that of the other 7 therapies (P > 0.05). In terms of microbiological response rate, eravacycline was significantly better than tigecycline [tigecycline vs. eravacycline: RR = 0.82, 95%CI (0.65,0.99)], and there was no significant difference between the other 6 regimens and eravacycline (P > 0.05). In terms of safety, the incidence of serious adverse events, discontinuation rate, and all-cause mortality of eravacycline were not significantly different from those of the other 7 treatment therapies (P > 0.05).

Conclusion

Based on the evidence generated by the current noninferiority clinical trial design, the efficacy and safety of eravacycline for the treatment of adults with cIAIs are not significantly different from those of the other 7 commonly used clinical antibiotics in China. In terms of microbiological response rate, eravacycline was significantly better than tigecycline. In view of the severe multidrug-resistant situation in China, existing drugs have difficulty meeting the needs of clinical treatment, and the new antibacterial drug eravacycline may be one of the preferred options for the treatment of cIAIs in adults.

Genetic diversity and multidrug resistance of phylogenic groups B2 and D in InPEC and ExPEC isolated from chickens in Central China

BACKGROUND

Avian colibacillosis is an infectious bacterial disease caused by avian pathogenic Escherichia coli (APEC). APEC causes a wide variety of intestinal and extraintestinal infections, including InPEC and ExPEC, which result in enormous losses in the poultry industry. In this study, we investigated the prevalence of InPEC and ExPEC in Central China, and the isolates were characterized using molecular approaches and tested for virulence factors and antibiotic resistance.

RESULTS

A total of 200 chicken-derived E. coli isolates were collected for study from 2019 and 2020. The prevalence of B2 and D phylogenic groups in the 200 chicken-derived E. coli was verified by triplex PCR, which accounted for 50.53% (48/95) and 9.52% (10/105) in ExPEC and InPEC, respectively. Additionally, multilocus sequence typing method was used to examine the genetic diversity of these E. coli isolates, which showed that the dominant STs of ExPEC included ST117 (n = 10, 20.83%), ST297 (n = 5, 10.42%), ST93 (n = 4, 8.33%), ST1426 (n = 4, 8.33%) and ST10 (n = 3, 6.25%), while the dominant ST of InPEC was ST117 (n = 2, 20%). Furthermore, antimicrobial susceptibility tests of 16 antibiotics for those strains were conducted. The result showed that more than 60% of the ExPEC and InPEC were resistant to streptomycin and nalidixic acid. Among these streptomycin resistant isolates (n = 49), 99.76% harbored aminoglycoside resistance gene strA, and 63.27% harbored strB. Among these nalidixic acid resistant isolates (n = 38), 94.74% harbored a S83L mutation in gyrA, and 44.74% harbored a D87N mutation in gyrA. Moreover, the prevalence of multidrug-resistant (MDR) in the isolates of ExPEC and InPEC was 31.25% (15/48) and 20% (2/10), respectively. Alarmingly, 8.33% (4/48) of the ExPEC and 20% (2/10) of the InPEC were extensively drug-resistant (XDR). Finally, the presence of 13 virulence-associated genes was checked in these isolates, which over 95% of the ExPEC and InPEC strains harbored irp2, feoB, fimH, ompT, ompA. 10.42% of the ExPEC and 10% of the InPEC were positive for kpsM. Only ExPEC isolates carried ibeA gene, and the rate was 4.17%. All tested strains were negative to LT and cnf genes. The carrying rate of iss and iutA were significantly different between the InPEC and ExPEC isolates (P < 0.01).

CONCLUSIONS

To the best of our knowledge, this is the first report on the highly pathogenic groups of InPEC and ExPEC in Central China. We find that 50.53% (48/95) of the ExPEC belong to the D/B2 phylogenic group. The emergence of XDR and MDR strains and potential virulence genes may indicate the complicated treatment of the infections caused by APEC. This study will improve our understanding of the prevalence and pathogenicity of APEC.

Diagnosis and Management of Intraabdominal Infection: Guidelines by the Chinese Society of Surgical Infection and Intensive Care and the Chinese College of Gastrointestinal Fistula Surgeons

The Chinese guidelines for IAI presented here were developed by a panel that included experts from the fields of surgery, critical care, microbiology, infection control, pharmacology, and evidence-based medicine. All questions were structured in population, intervention, comparison, and outcomes format, and evidence profiles were generated. Recommendations were generated following the principles of the Grading of Recommendations Assessment, Development, and Evaluation system or Best Practice Statement (BPS), when applicable. The final guidelines include 45 graded recommendations and 17 BPSs, including the classification of disease severity, diagnosis, source control, antimicrobial therapy, microbiologic evaluation, nutritional therapy, other supportive therapies, diagnosis and management of specific IAIs, and recognition and management of source control failure. Recommendations on fluid resuscitation and organ support therapy could not be formulated and thus were not included. Accordingly, additional high-quality clinical studies should be performed in the future to address the clinicians' concerns.

Risk Factors and Molecular Epidemiology of Complicated Intra-Abdominal Infections With Carbapenem-Resistant Enterobacteriaceae: A Multicenter Study in China

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) infections are associated with poor patient outcomes. Data on risk factors and molecular epidemiology of CRE in complicated intra-abdominal infections (cIAI) in China are limited. This study examined the risk factors of cIAI with CRE and the associated mortality based on carbapenem resistance mechanisms.

METHODS

In this retrospective analysis, we identified 1024 cIAI patients hospitalized from January 1, 2013 to October 31, 2018 in 14 intensive care units in China. Thirty CRE isolates were genotyped to identify β-lactamase-encoding genes.

RESULTS

Escherichia coli (34.5%) and Klebsiella pneumoniae (21.2%) were the leading pathogens. Patients with hospital-acquired cIAI had a lower rate of E coli (26.0% vs 49.1%; P < .001) and higher rate of carbapenem-resistant Gram-negative bacteria (31.7% vs 18.8%; P = .002) than those with community-acquired cIAI. Of the isolates, 16.0% and 23.4% of Enterobacteriaceae and K pneumoniae, respectively, were resistant to carbapenem. Most carbapenemase-producing (CP)-CRE isolates carried blaKPC (80.9%), followed by blaNMD (19.1%). The 28-day mortality was 31.1% and 9.0% in patients with CRE vs non-CRE (P < .001). In-hospital mortality was 4.7-fold higher for CP-CRE vs non-CP-CRE infection (P = .049). Carbapenem-containing combinations did not significantly influence in-hospital mortality of CP and non-CP-CRE. The risk factors for 28-day mortality in CRE-cIAI included septic shock, antibiotic exposure during the preceding 30 days, and comorbidities.

CONCLUSIONS

Klebsiella pneumoniae had the highest prevalence in CRE. Infection with CRE, especially CP-CRE, was associated with increased mortality in cIAI.

Analysis of Susceptibilities of Carbapenem Resistant Enterobacterales to Colistin in Intra-Abdominal, Respiratory and Urinary Tract Infections from 2015 to 2017

Purpose

To evaluate the susceptibility rates of carbapenem-resistant (CR)-Enterobacterales strains from Chinese intra-abdominal infections (IAI), respiratory tract infections (RTI) and urinary tract infections (UTI) between 2015 and 2017 to colistin.

Methods

In total, 7138 Enterobacterales including 1074 CR-Enterobacterales strains were isolated from IAI+UTI+RTI samples and collected in 21 hospitals across 7 regions of China. Antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards.

Results

From 2015 to 2017, E. coli (51.4%) and K. pneumoniae (30.0%) accounted for the majority of Enterobacterales isolated from IAIs, UTIs and RTIs. The percentage of CR strains within the species was highest for S. marcescens (27.9%), followed by K. pneumoniae (24.8%), P. mirabilis (22.6), K. oxytoca (19.5%), E. cloacae (17.7%), C. freundii (12.5%), K. aerogenes (11.0%) and lowest for E. coli (6.9%). Colistin susceptibilities were generally higher in CS than in CR isolates and were 83.5% for CR-E. coli, 88.6% for CR-K. pneumoniae, 79.2% for CR-E. cloacae and 87.5% for CR-K. aerogenes. For IAI and UTI isolates in particular, CR-E. coli and CR-K. pneumoniae showed a trend of decreasing susceptibility, which was especially noted for CR-E. coli in UTI isolates, and for both organisms in IAI isolates susceptibility dropped markedly in 2017.

Conclusion

Colistin was a last resort antibiotics for empirical CR-Enterobacterales treatments, since especially the percentage of CR-K. pneumoniae was 30.0% of all IAI, UTI and RTI isolates, with an incidence of 24.8% CR strains, of which 88.6% were susceptible to colistin. Also other analyzed CR-Enterobacterales showed colistin susceptibilities of ≥80.0%. However, resistance rates of IAI derived CR-K. pneumoniae and CR-E. coli, and CR-K. pneumoniae UTI isolates to colistin increased between 2015 and 2017, which should further be closely monitored.

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.

In vitro Activity of a New Fourth-Generation Cephalosporin, Cefoselis, Against Clinically Important Bacterial Pathogens in China

The objective of this study was to systematically evaluate the in vitro activity of cefoselis and other comparators against common bacterial pathogens collected from 18 hospitals across China. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method following Clinical and Laboratory Standards Institute (CLSI) guidelines. Cefoselis showed poor activity against extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, with susceptibility rates of < 10% each, while the susceptibility rates of this antibiotic against non-ESBL-producing strains of these organisms were 100%, 94.3%, and 97.0%, respectively. Cefoselis exhibited susceptibility rates of 56.7–83.3% against other tested Enterobacteriaceae isolates. For Acinetobacter baumannii and Pseudomonas aeruginosa isolates, the susceptibility rates to cefoselis were 18.7% and 73.3%, respectively. All methicillin-resistant Staphylococcus aureus (MRSA) strains were resistant to cefoselis, while all methicillin-sensitive S. aureus (MSSA) strains were susceptible to this antibiotic. In conclusion, cefoselis showed good activity against non-ESBL-producing E. coli, K. pneumoniae, and P. mirabilis, MSSA, and was also potent against Enterobacteriaceae, P. aeruginosa, and Streptococcus.

Antimicrobial Susceptibility of Microorganisms Isolated from Patients with Intraabdominal Infection in Korea: a Multicenter Study

BACKGROUND

This study evaluated the antimicrobial susceptibility of pathogens isolated from Korean patients with intraabdominal infections (IAIs).

METHODS

This multicenter study was conducted at 6 university-affiliated hospitals in Korea between 2016 and 2018. All patients with microbiologically proven IAIs were retrospectively included, while patients with spontaneous bacterial peritonitis or continuous ambulatory peritoneal dialysis peritonitis were excluded. Identification and antimicrobial susceptibility testing were performed using automated microbiology systems.

RESULTS

A total of 2,114 non-duplicated clinical isolates were collected from 1,571 patients. Among these pathogens, 510 (24.1%) were isolated from nosocomial infections, and 848 isolates (40.1%) were associated with complicated IAIs. The distribution of the microorganisms included aerobic gram-negative (62.6% of isolates), aerobic gram-positive (33.7%), anaerobic (0.9%), and fungal (2.8%) pathogens. The most common pathogens were Escherichia coli (23.8%), followed by Enterococcus spp. (23.1%) and Klebsiella spp. (19.8%). The susceptibility rates of E. coli and Klebsiella spp. to major antibiotics were as follows: amoxicillin/clavulanate (62.5%, 83.0%), cefotaxime (61.4%, 80.7%), ceftazidime (63.7%, 83.1%), cefepime (65.3%, 84.3%), ciprofloxacin (56.4%, 86.3%), piperacillin/tazobactam (99.0%, 84.8%), amikacin (97.4%, 98.3%), and imipenem (99.8%, 98.8%). The susceptibility rates of Enterococcus spp. to ampicillin were 61.0%, amoxicillin/clavulanate, 63.6%; ciprofloxacin, 49.7%; imipenem, 65.2%; and vancomycin, 78.2%. The susceptibility rates of Pseudomonas aeruginosa and Acinetobacter spp. to imipenem were 77.4% and 36.7%, respectively.

CONCLUSION

Enterococcus spp. with susceptibility to limited antibiotics was one of the main pathogens in Korean IAIs, along with E. coli and Klebsiella spp., which were highly susceptible to imipenem, amikacin, and piperacillin/tazobactam. Meanwhile, the low susceptibilities of E. coli or Klebsiella spp. to amoxicillin/clavulanate, advanced-generation cephalosporins, and ciprofloxacin should be considered when determining empirical antibiotic therapy in clinical practice.

Antimicrobial susceptibility changes of Escherichia coli and Klebsiella pneumoniae intra-abdominal infection isolate-derived pathogens from Chinese intra-abdominal infections from 2011 to 2015

Background

To explore the susceptibility trends of antimicrobials and resistance increase to antibiotics of Enterobacteriaceae isolated from patients in China with intra-abdominal infections (IAI) from 2011 to 2015.

Methods

MIC₉₀ and MIC₅₀ values of 12 commonly used antibiotics from Escherichia coli and Klebsiella pneumoniae isolated from IAI samples were determined.

Results

A total of 8,477 Gram-negative bacterial pathogens were collected from 21 medical centers in China. The majority of IAI isolate-derived pathogens were E. coli (3,854, 45.5%) and K. pneumoniae (1,670, 19.7%) of which 1,990 (23.5%) were consecutively collected from community acquired (CA) and 6,186 (73.0%) from hospital acquired (HA) IAIs. The drugs with the highest efficacy against E. coli and K. pneumoniae isolates derived from IAI samples were imipenem, ertapenem, amikacin and piperacillin-tazobactam. MIC₉₀ values for piperacillin-tazobactam were 64 µg/mL in 2015 with fluctuations from 16–64 µg/mL through the years for E. coli, but were stable at ≥64 µg/mL from 2011 to 2015 for K. pneumoniae isolates. Susceptibilities to ertapenem, imipenem and amikacin were high for E. coli isolates throughout the study, but K. pneumoniae isolated from abscesses, colon and peritoneal fluid collected from medical and surgical ICUs showed an increasing trend of carbapenem resistance in 2015.

Conclusion

In 2015 there was a trend of enhanced carbapenem resistance, particularly for K. pneumoniae isolated from IAI samples obtained from patients in ICUs.

Epidemiology and antimicrobial susceptibility profiles of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae and Escherichiacoli in China

OBJECTS

The retrospective study aimed to determine the prevalence rate and antimicrobial susceptibility of extended-spectrum beta-lactamases (ESBLs)-producing Klebsiella pneumoniae and Escherichia coli in 2013-2017 at a single center in China.

METHODS

Klebsiella pneumoniae and Escherichia coli data were collected from the microbiological laboratory. VITEK 2 compact system was used for the identification and antimicrobial susceptibility testing. ESBL status was determined as per the Clinical and Laboratory Standards Institute (CLSI) protocols microdilution method.

RESULTS

Among a total of 2774 strains of Klebsiella pneumoniae and 2154 strains of Escherichia coli, 15.79% and 36.86% were found to be ESBL producers, respectively. In all patients infected by ESBLs-producing strains, those over 60 years accounted for the largest proportion. Infection by ESBLs-producing Klebsiella pneumoniae was more common in male, while that by ESBLs-producing Escherichia coli was more common in female. Urine and respiratory secretions were the most common sources of ESBLs-producing strains; however, ESBLs-producing strains from urine had been significantly declined. No carbapenem-resistant isolate was found, and all ESBLs-producing strains were resistant to ceftriaxone, aztreonam, and piperacillin. There were no differences in resistance rates between ESBLs-producing Escherichia coli and Klebsiella pneumoniae to ceftazidime and cefepime; however, ESBLs-producing Klebsiella pneumoniae showed higher resistance rates to piperacillin/tazobactam, amikacin, gentamicin, and co-trimoxazole compared with ESBLs-producing Escherichia coli.

CONCLUSION

Different ESBLs-producing organisms have their own epidemiological characteristics, and the resistance of ESBLs-producing Klebsiella pneumoniae and Escherichia coli is different even to the same antibiotics. Therefore, it is important to continuously monitor the status of ESBLs-producing organisms, and an improved antimicrobial stewardship and infection control are much required.

Fluoroquinolone-based versus β-lactam-based regimens for complicated intra-abdominal infections: a meta-analysis of randomised controlled trials

Complicated intra-abdominal infections (cIAIs) are common and confer significant morbidity, mortality and costs. In this era of evolving antimicrobial resistance, selection of appropriate empirical antimicrobials is paramount. This systematic review and meta-analysis of randomised controlled trials compared the effectiveness and safety of fluoroquinolone (FQ)-based versus β-lactam (BL)-based regimens for the treatment of patients with cIAIs. Primary outcomes were treatment success in the clinically evaluable (CE) population and all-cause mortality in the intention-to-treat (ITT) population. Subgroup analyses were performed based on specific antimicrobials, infection source and isolated pathogens. Seven trials (4125 patients) were included. FQ-based regimens included moxifloxacin (four studies) or ciprofloxacin/metronidazole (three studies); BL-based regimens were ceftriaxone/metronidazole (three studies), carbapenems (two studies) or piperacillin/tazobactam (two studies). There was no difference in effectiveness in the CE (2883 patients; RR = 1.00, 95% CI 0.95-1.04) or ITT populations (3055 patients; RR = 0.97, 95% CI 0.94-1.01). Mortality (3614 patients; RR = 1.04, 95% CI 0.75-1.43) and treatment-related adverse events (2801 patients; RR = 0.97, 95% CI 0.70-1.33) were also similar. On subset analysis, moxifloxacin was slightly less effective than BLs in the CE (1934 patients; RR = 0.96, 95% CI 0.93-0.99) and ITT populations (1743 patients; RR = 0.94, 95% CI 0.91-0.98). Although FQ- and BL-based regimens appear equally effective and safe for the treatment of cIAIs, limited data suggest slightly inferior results with moxifloxacin. Selection of empirical coverage should be based on local bacterial epidemiology and patterns of resistance as well as antimicrobial stewardship protocols.

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.

Antimicrobial susceptibility of common pathogens isolated from postoperative intra-abdominal infections in Japan

The principle of empirical therapy for patients with intra-abdominal infections (IAI) should include antibiotics with activity against Enterobacteriaceae and Bacteroides fragilis group species. Coverage of Pseudomonas aeruginosa, Enterobacter cloacae, and Enterococcus faecalis is also recommended for hospital-associated IAI. A nationwide survey was conducted to investigate the antimicrobial susceptibility of pathogens isolated from postoperative IAI. All 504 isolates were collected at 26 institutions and referred to a central laboratory for susceptibility testing. Lower susceptibility rates to ciprofloxacin and cefepime were demonstrated in Escherichia coli. Among E. coli, 24.1% of strains produced extended-spectrum β-lactamase (ESBL). Carbapenems, piperacillin/tazobactam, cephamycins/oxacephem, aminoglycosides, and tigecycline had high activity against E. coli, including ESBL-producing isolates. Among E. cloacae, low susceptibility rates to ceftazidime were demonstrated, whereas cefepime retained its activity. P. aeruginosa revealed high susceptibility rates to all antimicrobials tested except for imipenem. Among B. fragilis group species, low levels of susceptibility were observed for cefoxitin, moxifloxacin, and clindamycin, and high susceptibility rates were observed for piperacillin/tazobactam, meropenem, and metronidazole. Ampicillin, piperacillin, and glycopeptides had good activity against E. faecalis. Imipenem had the highest activity against E. faecalis among carbapenems. In conclusion, we suggested the empirical use of antimicrobials with the specific intent of covering the main organisms isolated from postoperative IAI. Piperacillin/tazobactam, meropenem, or doripenem, are appropriate in critically ill patients. Combination therapy of cefepime (aztreonam in patients with β-lactam allergy) plus metronidazole plus glycopeptides, imipenem/cilastatin or cephamycins/oxacephem plus ciprofloxacin plus metronidazole are potential therapeutic options.

Shifting trends in bacteriology and antimicrobial resistance among gastrointestinal fistula patients in China: an eight-year review in a tertiary-care hospital

Background

The purpose of this study was to determine the shifting trends in bacteriology and antimicrobial resistance of infectious specimens isolated from gastrointestinal (GI) fistula patients over eight years in China.

Methods

We retrospectively reviewed the microbial records of intra-abdominal specimens at a teaching hospital from 2008 to 2015. Study period was divided into the first half (2008–2011) and the second half (2012–2015). All isolates underwent antibiotic susceptibility testing by the micro dilution method.

Results

A total of 874 intra-abdominal isolates were consecutively collected from 502 GI fistula patients (mean age, 46.5 years, 71.1% male) during the study period. Patients in the second study period (2012–2015) were older (>65 years) and more likely to have experienced cancer. Over the entire study period, most infections were caused by E. coli (24.2%) and K. pneumonia (14.1%). There was a significant decrease in the proportion E. coli isolates that were extended- spectrum beta-lactamase (ESBL)-positive (P = 0.026). The proportion of E. coli resistant to imipenem increased from 14.3% in 2008–2011 to 25.9% in 2012–2015 (P = 0.037). Imipenem resistance prevalence was higher in ESBL-negative bacteria than ESBL-positive bacteria for both E. coli and K. pneumonia (P < 0.001). In Enterococcus, significant increase in resistance to ampicillin (P = 0.01) and moxifloxacin (P = 0.02) over time were observed. In Staphylococcus and fungi, rates of antibiotic resistance did not significantly change over the study period.

Conclusions

Gram-negative bacteria predominated as causative agents of intra-abdominal infections in GI fistula patients, and there was an increase in levels of resistance to certain antibiotics, particularly carbapenems. Infection control and source control are important tools available to surgeons to prevent the emergence of antibiotic-resistant pathogens.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2744-7) contains supplementary material, which is available to authorized users.

Susceptibility to penicillin derivatives among third-generation cephalosporin-resistant Enterobacteriaceae recovered on hospital admission

As part of the multicenter Antibiotic Therapy Optimisation Study-the largest study on the prevalence of third-generation cephalosporin-resistant Enterobacteriaceae carriage upon hospital admission-minimum inhibitory concentration values were generated for ampicillin/sulbactam, amoxicillin/clavulanic acid, piperacillin/tazobactam, mecillinam, mecillinam/clavulanic acid, and temocillin against third-generation cephalosporin-resistant Escherichia coli, Klebsiella species and Enterobacter species.