Microbiological profile of patients treated for postoperative peritonitis: temporal trends 1999-2019

BACKGROUND

Temporal changes in the microbiological resistance profile have been reported in several life-threatening infections. However, no data have ever assessed this issue in postoperative peritonitis (POP). Our purpose was to assess the rate of multidrug-resistant organisms (MDROs) in POP over a two-decade period and to analyse their influence on the adequacy of empirical antibiotic therapy (EAT).

METHODS

This retrospective monocentric analysis (1999-2019) addressed the changes over time in microbiologic data, including the emergence of MDROs and the adequacy of EAT for all intensive care unit adult patients treated for POP. The in vitro activities of 10 antibiotics were assessed to determine the most adequate EAT in the largest number of cases among 17 antibiotic regimens in patients with/without MDRO isolates. Our primary endpoint was to determine the frequency of MDRO and their temporal changes. Our second endpoint assessed the impact of MDROs on the adequacy of EAT per patient and their temporal changes based on susceptibility testing. In this analysis, the subgroup of patients with MDRO was compared with the subgroup of patients free of MDRO.

RESULTS

A total of 1,318 microorganisms were cultured from 422 patients, including 188 (45%) patients harbouring MDROs. The growing proportions of MDR Enterobacterales were observed over time (p = 0.016), including ESBL-producing strains (p = 0.0013), mainly related to Klebsiella spp (p < 0.001). Adequacy of EAT was achieved in 305 (73%) patients. Decreased adequacy rates were observed when MDROs were cultured [p = 0.0001 vs. MDRO-free patients]. Over the study period, decreased adequacy rates were reported for patients receiving piperacillin/tazobactam in monotherapy or combined with vancomycin and imipenem/cilastatin combined with vancomycin (p < 0.01 in the three cases). In patients with MDROs, the combination of imipenem/cilastatin + vancomycin + amikacin or ciprofloxacin reached the highest adequacy rates (95% and 91%, respectively) and remained unchanged over time.

CONCLUSIONS

We observed high proportions of MDRO in patients treated for POP associated with increasing proportions of MDR Enterobacterales over time. High adequacy rates were only achieved in antibiotic combinations involving carbapenems and vancomycin, while piperacillin/tazobactam is no longer a drug of choice for EAT in POP in infections involving MDRO.

Cefoxitin versus carbapenems as definitive treatment for extended-spectrum β-lactamase-producing Klebsiella pneumoniae bacteremia in intensive care unit: a propensity-matched retrospective analysis

BACKGROUND

Despite cefoxitin's in vitro resistance to hydrolysis by extended-spectrum beta-lactamases (ESBL), treatment of ESBL-producing Klebsiella pneumoniae (KP) infections with cefoxitin remains controversial. The aim of our study was to compare the clinical efficacy of cefoxitin as definitive antibiotic therapy for patients with ESBL-KP bacteremia in intensive care unit, versus carbapenem therapy.

METHODS

This retrospective study included all patients with monomicrobial bacteremia hospitalized in intensive care unit between January 2013 and January 2023 at the University Hospital of Guadeloupe. The primary outcome was the 30-day clinical success defined as a composite endpoint: 30-day survival, absence of relapse and no change of antibiotic therapy. Cox regression including a propensity score (PS) and PS-based matched analysis were performed for endpoint analysis.

RESULTS

A total of 110 patients with bloodstream infections were enrolled. Sixty-three patients (57%) received definitive antibiotic therapy with cefoxitin, while forty-seven (43%) were treated with carbapenems. 30-day clinical success was not significantly different between patients treated with cefoxitin (57%) and carbapenems (53%, p = 0.823). PS-adjusted and PS-matched analysis confirmed these findings. Change of definitive antibiotic therapy was more frequent in the cefoxitin group (17% vs. 0%, p = 0.002). No significant differences were observed for the other secondary endpoints. The acquisition of carbapenem-resistant Pseudomonas aeruginosa was significantly higher in patients receiving carbapenem therapy (5% vs. 23%, p = 0.007).

CONCLUSIONS

Our results suggest that cefoxitin as definitive antibiotic therapy could be a therapeutic option for some ESBL-KP bacteremia, sparing carbapenems and reducing the selection of carbapenem-resistant Pseudomonas aeruginosa strains.

Acquisition of extended-spectrum cephalosporin-resistant Gram-negative bacteria: epidemiology and risk factors in a 6-year cohort of 507 severe trauma patients

OBJECTIVES

Severe trauma patients are at higher risk of infection and often exposed to antibiotics, which could favor acquisition of antimicrobial resistance. In this study, we aimed to assess prevalence, acquisition, and factors associated with acquisition of extended-spectrum cephalosporin-resistant Gram-negative bacteria (ESCR-GNB) in severe trauma patients.

METHODS

We conducted a retrospective monocentric cohort study in a French level one Regional Trauma Centre between 01 January 2010and 31 December 2015. Patients admitted for ≥ 7 days, with an Injury Severity Score ≥ 15, and ≥ 1 microbiological sample were included in the analysis. Prevalence and acquisition rate of ESCR-GNB were determined then, factors associated with ESCR-GNB acquisition were assessed using a Cox model.

RESULTS

Of 1873 patients admitted during the study period, 507 were included (median Injury Severity Score = 29 [22-34] and median intensive care unit length of stay = 16 days [10-28]). Most of them (450; 89%) had an antimicrobial therapy. Prevalence of ESCR-GNB increased from 13% to 33% during intensive care unit stay, bringing the ESCR-GNB acquisition rate to 29%. Acquisition of ESCR-GNB was mainly related to AmpC beta-lactamase Enterobacterales and was independently associated with mechanical ventilation needs (hazard ratio [HR] = 6.39; 95% confidence interval [CI] [1.51-27.17]; P = 0.01), renal replacement therapy needs (HR = 2.44; 95% CI [1.24-4.79]; P = 0.01), exposure to cephalosporins (HR = 1.06; 95% CI [1.01-1.12]; P = 0.02), and/or combination therapy with non-beta-lactam antibiotics such as vancomycin, linezolid, clindamycin, or metronidazole (HR = 1.03; 95% CI [1.01-1.06]; P = 0.02).

CONCLUSIONS

Acquisition of ESCR-GNB was prevalent in severe trauma patients. Our results suggest selecting antibiotics with caution, particularly in the most severely ill.

Limited Transmission of Klebsiella pneumoniae among Humans, Animals, and the Environment in a Caribbean Island, Guadeloupe (French West Indies)

Guadeloupe (French West Indies), a Caribbean island, is an ideal place to study the reservoirs of the Klebsiella pneumoniae species complex (KpSC) and identify the routes of transmission between human and nonhuman sources due to its insularity, small population size, and small area. Here, we report an analysis of 590 biological samples, 546 KpSC isolates, and 331 genome sequences collected between January 2018 and May 2019. The KpSC appears to be common whatever the source. Extended-spectrum-β-lactamase (ESBL)-producing isolates (21.4%) belonged to K. pneumoniae sensu stricto (phylogroup Kp1), and all but one were recovered from the hospital setting. The distribution of species and phylogroups across the different niches was clearly nonrandom, with a distinct separation of Kp1 and Klebsiella variicola (Kp3). The most frequent sequence types (STs) (≥5 isolates) were previously recognized as high-risk multidrug-resistant (MDR) clones, namely, ST17, ST307, ST11, ST147, ST152, and ST45. Only 8 out of the 63 STs (12.7%) associated with human isolates were also found in nonhuman sources. A total of 22 KpSC isolates were defined as hypervirulent: 15 associated with human infections (9.8% of all human isolates), 4 (8.9%) associated with dogs, and 3 (15%) associated with pigs. Most of the human isolates (33.3%) belonged to the globally successful sublineage CG23-I. ST86 was the only clone shared by a human and a nonhuman (dog) source. Our work shows the limited transmission of KpSC isolates between human and nonhuman sources and points to the hospital setting as a cornerstone of the spread of MDR clones and antibiotic resistance genes. IMPORTANCE In this study, we characterized the presence and genomic features of isolates of the Klebsiella pneumoniae species complex (KpSC) from human and nonhuman sources in Guadeloupe (French West Indies) in order to identify the reservoirs and routes of transmission. This is the first study in an island environment, an ideal setting that limits the contribution of external imports. Our data showed the limited transmission of KpSC isolates between the different compartments. In contrast, we identified the hospital setting as the epicenter of antibiotic resistance due to the nosocomial spread of successful multidrug-resistant (MDR) K. pneumoniae clones and antibiotic resistance genes. Ecological barriers and/or limited exposure may restrict spread from the hospital setting to other reservoirs and vice versa. These results highlight the need for control strategies focused on health care centers, using genomic surveillance to limit the spread, particularly of high-risk clones, of this important group of MDR pathogens.

Retrospective analysis of a large single cohort of Enterobacteriaceae producing extended-spectrum B-lactamase (E-ESBL) patients: incidence, microbiology, and mortality

We conducted a retrospective study from 2005 to 2019 to describe the epidemiology and mortality of enterobacterial producing extended-spectrum β-lactamase (E-ESBL) infections in our university hospital over a 17-year period of time. Clinical and microbiological data were extracted from different software used for continuous surveillance. Stool samples from systematic screening for E-ESBL colonization were excluded from the study. The incidence rate of infected patient was calculated by E-ESBL species and by year. A comparison of mortality rate in patients with bloodstream infections versus other types of infections was conducted using a Kaplan-Meier method survival curves. A log rank test (with a risk of 5%) was carried out. A total of 3324 patients with E-ESBL infection were included with an increased incidence density per 1000 days of hospitalization from 0.03 in 2005 to 0.47 in 2019. Escherichia coli was the most frequently isolated pathogen (64%). Global mortality rate was significantly higher with E. coli than with Klebsiella spp. and Enterobacter spp. (p < 0.001). Mortality was higher in patients with E-ESBL bloodstream infection than in patients with other type of E-ESBL infection (p < 0.001). Our study showed a significant increase of the E-ESBL incidence density over a 17-year period survey with a higher mortality in patients with E-ESBL bacteremia. This highlights the need to continue efforts to control the spread of these multi-resistant bacteria in our institution.

Polyclonal spread of blaCTX-M-15 through high-risk clones of Escherichia coli at a tertiary hospital in Ethiopia

OBJECTIVE

The burden of antimicrobial resistance and spread of epidemic clones are rarely reported from low-income countries. We aimed to investigate genome-based epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) at a tertiary hospital in Jimma, Ethiopia.

METHODS

Bacteria were isolated from clinical specimens obtained from Jimma Medical Center and subjected to species identification (MALDI-TOF), antibiotic susceptibility testing (disk diffusion), and whole genome sequencing (Illumina HiSeq2500). Genomic data analysis was performed using the Enterobase and Center for Genomic Epidemiology bioinformatics pipelines. A maximum likelihood tree was generated using FastTree/2.1.8 based on SNPs in shared genomic regions to identify transmission clusters.

RESULT

E. coli isolates (n=261) were collected from 1,087 single non-repeat clinical specimens over a period of five months in 2016. The prevalence of ESBL-EC was (54.7%, 143/261), and 96% of these isolates were resistant to multiple classes of antibiotics. ESBL-gene bla_CTX-M-15 was present in 88.4.% of the isolates (122/138). Genes conferring resistance to aminoglycosides and ciprofloxacin - aac(6')-Ib-cr (62.3%, 86/138), phenicols - catB3 (56.5%, 78/138), sulfonamides - sul1 (68.1%, 94/138), trimethoprim - dfrA17 (57.9%, 80/138) and macrolides - mph(A) (67.3%, 93/138) were detected. The most prevalent sequence types were ST410 (23%), ST648 (17%), ST131 (10%), and ST167 (7%). Isolates of same sequence type collected from different units of the hospital were highly similar in SNP-analysis.

CONCLUSION

A high prevalence of ESBL, and dissemination of bla_CTX-M-15 through multiple high-risk clones of E. coli, was detected. The nosocomial spread of multidrug-resistant ESBL-EC within the hospital puts vulnerable patients at risk for difficult-to-treat infections.

Antimicrobial resistance and antibiotic consumption in intensive care units, Switzerland, 2009 to 2018

Background

Intensive care units (ICU) constitute a high-risk setting for antimicrobial resistance (AMR).

Aim

We aimed to describe secular AMR trends including meticillin-resistant Staphylococcus aureus (MRSA), glycopeptide-resistant enterococci (GRE), extended-spectrum cephalosporin-resistant Escherichia coli (ESCR-EC) and Klebsiella pneumoniae (ESCR-KP), carbapenem-resistant Enterobacterales (CRE) and Pseudomonas aeruginosa (CRPA) from Swiss ICU. We assessed time trends of antibiotic consumption and identified factors associated with CRE and CRPA.

Methods

We analysed patient isolate and antibiotic consumption data of Swiss ICU sent to the Swiss Centre for Antibiotic Resistance (2009–2018). Time trends were assessed using linear logistic regression; a mixed-effects logistic regression was used to identify factors associated with CRE and CRPA.

Results

Among 52 ICU, MRSA decreased from 14% to 6% (p = 0.005; n = 6,465); GRE increased from 1% to 3% (p = 0.011; n = 4,776). ESCR-EC and ESCR-KP increased from 7% to 15% (p < 0.001, n = 10,648) and 5% to 11% (p = 0.002; n = 4,052), respectively. CRE, mostly Enterobacter spp., increased from 1% to 5% (p = 0.008; n = 17,987); CRPA remained stable at 27% (p = 0.759; n = 4,185). Antibiotic consumption in 58 ICU increased from 2009 to 2013 (82.5 to 97.4 defined daily doses (DDD)/100 bed-days) and declined until 2018 (78.3 DDD/100 bed-days). Total institutional antibiotic consumption was associated with detection of CRE in multivariable analysis (odds ratio per DDD: 1.01; 95% confidence interval: 1.0–1.02; p = 0.004).

Discussion

In Swiss ICU, antibiotic-resistant Enterobacterales have been steadily increasing over the last decade. The emergence of CRE, associated with institutional antibiotic consumption, is of particular concern and calls for reinforced surveillance and antibiotic stewardship in this setting.

Genetic basis of molecular mechanisms in β-lactam resistant gram-negative bacteria

Antibiotic-resistant bacteria are considered one of the major global threats to human and animal health. The most harmful among the resistant bacteria are β-lactamase producing Gram-negative species (β-lactamases). β-lactamases constitute a paradigm shift in the evolution of antibiotic resistance. Therefore, it is imperative to present a comprehensive review of the mechanisms responsible for developing antimicrobial resistance. Resistance due to β-lactamases develops through a variety of mechanisms, and the number of resistant genes are involved that can be transferred between bacteria, mostly via plasmids. Over time, these new molecular-based resistance mechanisms have been progressively disclosed. The present review article provides information on the recent findings regarding the molecular mechanisms of resistance to β-lactams in Gram-negative bacteria, including CTX-M-type ESBLs with methylase activity, plasmids harbouring phages with β-lactam resistance genes, the co-presence of β-lactam resistant genes of unique combinations and the presence of β-lactam and non-β-lactam antibiotic-resistant genes in the same bacteria. Keeping in view, the molecular level resistance development, multifactorial and coordinated measures may be taken to counter the challenge of rapidly increasing β-lactam resistance.

Antibiotic prescriptions and risk factors for antimicrobial resistance in patients hospitalized with urinary tract infection: a matched case-control study using the French health insurance database (SNDS)

BACKGROUND

Antibiotic resistance is increasing among urinary pathogens, resulting in worse clinical and economic outcomes. We analysed factors associated with antibiotic-resistant bacteria (ARB) in patients hospitalized for urinary tract infection, using the comprehensive French national claims database.

METHODS

Hospitalized urinary tract infections were identified from 2015 to 2017. Cases (due to ARB) were matched to controls (without ARB) according to year, age, sex, infection, and bacterium. Healthcare-associated (HCAI) and community-acquired (CAI) infections were analysed separately; logistic regressions were stratified by sex.

RESULTS

From 9460 cases identified, 6468 CAIs and 2855 HCAIs were matched with controls. Over a 12-months window, the risk increased when exposure occurred within the last 3 months. The following risk factors were identified: antibiotic exposure, with an OR reaching 3.6 [2.8-4.5] for men with CAI, mostly associated with broad-spectrum antibiotics; surgical procedure on urinary tract (OR 2.0 [1.5-2.6] for women with HCAI and 1.3 [1.1-1.6] for men with CAI); stay in intensive care unit > 7 days (OR 1.7 [1.2-2.6] for men with HCAI). Studied co-morbidities had no impact on ARB.

CONCLUSIONS

This study points out the critical window of 3 months for antibiotic exposure, confirms the impact of broad-spectrum antibiotic consumption on ARB, and supports the importance of prevention during urological procedures, and long intensive care unit stays.

Pharmacodynamics of Cefepime Combined with the Novel Extended-Spectrum-β-Lactamase (ESBL) Inhibitor Enmetazobactam for Murine Pneumonia Caused by ESBL-Producing Klebsiella pneumoniae

Klebsiella pneumoniae strains that produce extended-spectrum beta lactamases (ESBLs) are a persistent public health threat. There are relatively few therapeutic options, and there is undue reliance on carbapenems. Alternative therapeutic options are urgently required. A combination of cefepime and the novel beta lactamase inhibitor enmetazobactam is being developed for the treatment of serious infections caused by ESBL-producing organisms. The pharmacokinetics-pharmacodynamics (PK-PD) of cefepime-enmetazobactam against ESBL-producing K. pneumoniae was studied in a neutropenic murine pneumonia model. Dose-ranging studies were performed. Dose fractionation studies were performed to define the relevant PD index for the inhibitor. The partitioning of cefepime and enmetazobactam into the lung was determined by comparing the area under the concentration-time curve (AUC) in plasma and epithelial lining fluid. The magnitude of drug exposure for cefepime-enmetazobactam required for logarithmic killing in the lung was defined using 3 ESBL-producing strains. Cefepime, given as 100 mg/kg of body weight every 8 h intravenously (q8h i.v.), had minimal antimicrobial effect. When this background regimen of cefepime was combined with enmetazobactam, a half-maximal effect was induced with enmetazobactam at 4.71 mg/kg q8h i.v. The dose fractionation study suggested both fT > threshold and fAUC:MIC are relevant PD indices. The AUC_ELF:AUC_plasma ratio for cefepime and enmetazobactam was 73.4% and 61.5%, respectively. A ≥2-log kill in the lung was achieved with a plasma and ELF cefepime fT > MIC of ≥20% and enmetazobactam fT > 2 mg/liter of ≥20% of the dosing interval. These data and analyses provide the underpinning evidence for the combined use of cefepime and enmetazobactam for nosocomial pneumonia.

High Prevalence of ST131 Subclades C2-H30Rx and C1-M27 Among Extended-Spectrum β-Lactamase-Producing Escherichia coli Causing Human Extraintestinal Infections in Patients From Two Hospitals of Spain and France During 2015

The present study was carried out to evaluate the prevalence of sequence type 131 (ST131) among 188 extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) collected in 2015 in Lucus Augusti University hospital (Lugo, Spain) and AP-HP Beaujon hospital (Clichy, France) with regard to other STs and to characterize, the types of ESBL produced, serotypes, virulence factor (VF)-encoding genes and the ST131 clades and subclades. ST131 was detected in 33 (39.1%) and 46 (47.9%) of the isolates in Lucus Augusti and Beaujon, respectively. The 109 remaining isolates displayed 57 other STs, the following STs being displayed by at least three isolates: ST10 (8 isolates), ST23 (3), ST38 (4), ST58 (3), ST88 (5), ST95 (4), ST167 (3), ST354 (5), ST361 (3), ST410 (6), ST648 (4), ST744 (3), and ST1615 (6). ST354, ST410, and ST1615 were significantly (P < 0.05) more frequent in Lucus Augusti (5.4%, 6.5%, and 6.5%) than in Beaujon (0% for the three STs). The new globally emerging clone ST1193 among extraintestinal clinical ESBL-EC was identified in one isolate from France and one from Spain. CTX-M-15 was the commonest ESBL detected in the two hospitals (44.6% in Lucus Augusti and 50.0% in Beaujon). CTX-M-14 was significantly (P = 0.0003) more frequent in Lucus Augusti (31.5%) than in Beaujon (10.4%), whereas CTX-M-1 (20.8 vs. 7.6%; P = 0.008) and CTX-M-27 (15.6 vs. 6.5%; P = 0.0389) were more frequent in Beaujon than in Lucus Augusti. The ST131 isolates showed a higher virulence score (mean 13.367) compared with the non-ST131 isolates (mean 7.661) (P < 0.001). Among the 79 ST131 isolates, most of them (52; 65.8%) belonged to subclade C2 (also known as subclone H30Rx) followed by those belonging to subclade C1 (cluster C1-M27: 16 isolates, 20.3%; cluster non-C1-M27: 6 isolates, 7.6%) and clade A (4 isolates; 5.1%). The C2 subclade isolates showed a higher VF-encoding gene score (mean 14.250) compared with the C1-M27 cluster isolates (mean 10.875) (P < 0.001). In conclusion, this study highlights the epidemiological differences between the ESBL-EC isolated from two hospitals of France and Spain obtain in 2015 and reports, for the first time, the presence of clone ST1193 in Spain.

Impact of colonization pressure on acquisition of extended-spectrum β-lactamase-producing Enterobacterales and meticillin-resistant Staphylococcus aureus in two intensive care units: a 19-year retrospective surveillance

BACKGROUND

Colonization pressure is a risk factor for intensive care unit (ICU)-acquired multi-drug-resistant organisms (MDROs).

AIM

To measure the long-term respective impact of colonization pressure on ICU-acquired extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) and meticillin-resistant Staphylococcus aureus (MRSA).

METHODS

All patients admitted to two ICUs (medical and surgical) between January 1997 and December 2015 were included in this retrospective observational study. Rectal and nasal surveillance cultures were obtained at admission and weekly thereafter. Contact precautions were applied for colonized or infected patients. Colonization pressure was defined as the ratio of the number of MDRO-positive patient-days (PDs) of each MDRO to the total number of PDs. Single-level negative binomial regression models were used to evaluate the incidence of weekly MDRO acquisition.

FINDINGS

Among the 23,423 patients included, 2327 (10.0%) and 1422 (6.1%) were colonized with ESBL-PE and MRSA, respectively, including 660 (2.8%) and 351 (1.5%) acquisitions. ESBL-PE acquisition increased from 0.51/1000 patient-exposed days (PEDs) in 1997 to 6.06/1000 PEDs in 2015 (P<0.001). In contrast, MRSA acquisition decreased steadily from 3.75 to 0.08/1000 PEDs (P<0.001). Controlling for period-level covariates, colonization pressure in the previous week was associated with MDRO acquisition for ESBL-PE (P<0.001 and P=0.04 for medical and surgical ICU, respectively), but not for MRSA (P=0.34 and P=0.37 for medical and surgical ICU, respectively). The increase in colonization pressure was significant above 100/1000 PDs for ESBL-PE.

CONCLUSION

Colonization pressure contributed to the increasing incidence of ESBL-PE but not MRSA. This study suggests that preventive control measures should be customized to MDROs.

Non-intravenous carbapenem-sparing antibiotics for definitive treatment of bacteraemia due to Enterobacteriaceae producing extended-spectrum β-lactamase (ESBL) or AmpC β-lactamase: A propensity score study

Carbapenems are considered the treatment of choice for extended-spectrum β-lactamase (ESBL)- or AmpC β-lactamase-producing Enterobacteriaceae bacteraemia. Data on the effectiveness of non-intravenous carbapenem-sparing antibiotic options are limited. This study compared the 30-day mortality and clinical failure associated with the use of carbapenems versus alternative non-intravenous antibiotics for the definitive treatment of ESBL/AmpC-positive Enterobacteriaceae bacteraemia. This 12-year retrospective study (2004-2015) included all patients with bacteraemia due to ESBL/AmpC-producing Enterobacteriaceae at a Spanish hospital. Given the lack of randomisation of initial therapies, a propensity score for receiving carbapenems was calculated. There were 1115 patients with a first episode of bacteraemia due to Escherichia coli or Klebsiella pneumoniae, of which 123 (11.0%) were ESBL/AmpC-positive. There were 101 eligible patients: 59 in the carbapenem group and 42 in the alternative treatment group (trimethoprim/sulfamethoxazole 59.5%, quinolones 21.4%). The most frequent sources of infection were urinary (63%) and biliary (15%). Compared with the carbapenem group, patients treated with an alternative regimen had a shorter hospital stay [median (IQR) 7 (5-10) days vs. 12 (9-18) days; P < 0.001]. Use of an alternative non-intravenous therapy did not increase mortality (OR = 0.27, 95% CI 0.05-1.61; P = 0.15). After controlling for confounding factors with the propensity score, the adjusted OR of carbapenem treatment was 4.95 (95% CI 0.94-26.01; P = 0.059). Alternative non-intravenous carbapenem-sparing antibiotics could have a role in the definitive treatment of ESBL/AmpC-positive Enterobacteriaceae bacteraemia, allowing a reduction in carbapenem use. Use of trimethoprim/sulfamethoxazole in this series showed favourable results.

Risk Factors for Carbapenem-resistant Klebsiella pneumoniae Infection and Mortality of Klebsiella pneumoniae Infection

Background:

Klebsiella pneumoniae (KP) is a pathogen commonly causing nosocomial infection. Carbapenem-resistant KP (CRKP) is more resistant to multiple antimicrobial drugs than carbapenem-susceptible KP (CSKP) isolates. The aim of the present study was to identify the risk factors for CRKP infection and the predictors of mortality among KP-infected adult patients.

Methods:

Patients with CRKP and CSKP infection were categorized as the case group and control group, respectively, and we conducted a 1:1 ratio case-control study on these groups. The CRKP isolates collected were tested for antimicrobial susceptibility and presence of KP carbapenemase (KPC) gene. Clinical data were collected to identify risk factors for CRKP infection and mortality of KP infection. Risk factors were analyzed under univariable and multivariable logistic regression model.

Results:

The independent risk factors for CRKP infection were admission to Intensive Care Unit (odds ratio [OR]: 15.486, 95% confidence interval [CI]: 3.175–75.541, P < 0.001); use of β-lactams and β-lactamase inhibitor combination (OR: 4.765, 95% CI: 1.508–15.055, P = 0.008); use of cephalosporins (OR: 8.033, 95% CI: 1.623–39.763, P = 0.011); fluoroquinolones (OR: 6.090, 95% CI: 1.343–27.613, P = 0.019); and indwelling of urethral catheter (OR: 6.164, 95% CI: 1.847–20.578, P = 0.003). However, older age (OR: 1.079, 95% CI: 1.005–1.158, P = 0.036), Charlson comorbidity index (OR: 4.690, 95% CI: 2.094–10.504, P = 0.000), and aminoglycoside use (OR: 670.252, 95% CI: 6.577–68,307.730, P = 0.006) were identified as independent risk factors for patient deaths with KP infection. The mortality of CRKP group was higher than that of the CSKP group. KPC gene did not play a role in the CRKP group. CRKP mortality was high.

Conclusion:

Implementation of infection control measures and protection of the immunefunction are crucial.

Association between excreta management and incidence of extended-spectrum β-lactamase-producing Enterobacteriaceae: role of healthcare workers' knowledge and practices

BACKGROUND

The spread of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) in healthcare environments has become a major public health threat in recent years.

AIM

To assess how healthcare workers (HCWs) manage excreta and the possible association with the incidence of ESBL-PE.

METHODS

Eight hundred HCWs and 74 nurse-supervisors were questioned through two self-report questionnaires in order to assess their knowledge and practices, and to determine the equipment utilized for excreta management in 74 healthcare departments. Performance on equipment utilized, knowledge and practices were scored as good (score of 1), intermediate (score of 2) or poor (score of 3) on the basis of pre-established thresholds. Linear regression was performed to evaluate the association between HCWs' knowledge/practices and the incidence of ESBL-PE.

FINDINGS

Six hundred and eighty-eight HCWs (86%) and all nurse-supervisors participated in the survey. The proportions of respondents scoring 1, 2 and 3 were: 14.8%, 71.6% and 17.6% for equipment; 30.1%, 40.6 % and 29.3% for knowledge; and 2.0%, 71.9% and 26.1% for practices, respectively. The single regression mathematic model highlighted that poor practices (score of 3) among HCWs was significantly associated with increased incidence of ESBL-PE (P = 0.002).

CONCLUSIONS

A positive correlation was found between HCWs' practices for managing excreta and the incidence of ESBL-PE, especially in surgical units. There is an urgent need for development of public health efforts to enhance knowledge and practices of HCWs to better control the spread of multi-drug-resistant bacteria, and these should be integrated within infection control programmes.

Evaluation of ceftriaxone prescriptions in the emergency department of a university hospital: an urgent need for improvement and alternative therapy

To evaluate the relevance of ceftriaxone prescriptions in an emergency department of a university hospital and suggest whenever possible an antibiotic alternative with a lower ecological impact. All ceftriaxone prescriptions in the first complete week of each month during the year 2016, in the emergency department of the Grenoble university hospital, have been analyzed by an IDS referent in antibiotic prescriptions. Ceftriaxone prescription was considered appropriate if justified (an antibiotic must be used), relevant (ceftriaxone is a good choice), and adapted (in terms of dose, route, and period of administration), regardless of a potential antibiotic association, consistent with international recommendations. We considered patient outcome regarding the quality of initial prescription. Additionally, alternatives were suggested for relevant prescriptions. We included 327 patients, of which ceftriaxone prescriptions were not appropriate in 37.6% of cases: 13.5% were not justified, 12.8% not relevant, and 11.3% not adapted. The main factors associated with unjustified prescriptions were urinary, dermatological, and less frequent infection sites (p < 0.001). The main factors associated with irrelevant prescriptions were patients carrying multi-resistant bacteria (p = 0.002) or already following an antibiotic prescription at emergency department admission (p = 0.024). Antibiotic prescriptions were poorly adapted in patients with a creatinine rate over 150 μmol/L (p < 0.001) and septic shocks (p = 0.032). No difference was found concerning the hospital length of stay comparing appropriate initial prescriptions to inappropriate ones. However, alternatives with lower ecological impact were suggested in 55.2% of relevant prescriptions. In emergency departments, it is crucial to preserve ceftriaxone, selecting better indications and considering alternatives.

Infectious Diseases Consultation Reduces 30-Day and 1-Year All-Cause Mortality for Multidrug-Resistant Organism Infections

Background

Multidrug-resistant organism (MDRO) infections are associated with high mortality and readmission rates. Infectious diseases (ID) consultation improves clinical outcomes for drug-resistant Staphylococcus aureus bloodstream infections. Our goal was to determine the association between ID consultation and mortality following various MDRO infections.

Methods

This study was conducted with a retrospective cohort (January 1, 2006–October 1, 2015) at an academic tertiary referral center. We identified patients with MDROs in a sterile site or bronchoalveolar lavage/bronchial wash culture. Mortality and readmissions within 1 year of index culture were identified, and the association of ID consultation with these outcomes was determined using Cox proportional hazards models with inverse weighting by the propensity score for ID consultation.

Results

A total of 4214 patients with MDRO infections were identified. ID consultation was significantly associated with reductions in 30-day and 1-year mortality for resistant S. aureus (hazard ratio [HR], 0.48; 95% confidence interval [CI], 0.36–0.63; and HR, 0.73, 95% CI, 0.61–0.86) and Enterobacteriaceae (HR, 0.41; 95% CI, 0.27–0.64; and HR, 0.74; 95% CI, 0.59–0.94), and 30-day mortality for polymicrobial infections (HR, 0.51; 95% CI, 0.31–0.86) but not Acinetobacter or Pseudomonas. For resistant Enterococcus, ID consultation was marginally associated with decreased 30-day mortality (HR, 0.81; 95% CI, 0.62–1.06). ID consultation was associated with reduced 30-day readmission for resistant Enterobacteriaceae.

Conclusions

ID consultation was associated with significant reductions in 30-day and 1-year mortality for resistant S. aureus and Enterobacteriaceae, and 30-day mortality for polymicrobial infections. There was no association between ID consultation and mortality for patients with resistant Pseudomonas, Acinetobacter, or Enterococcus, possibly due to small sample sizes. Our results suggest that ID consultation may be beneficial for patients with some MDRO infections.

Monitoring antimicrobial resistance (AMR) using CUSUM control charts

We evaluated the use of the Cumulative Summation (CUSUM) control chart methodology for detection of an excessive increase in antimicrobial-resistant (AMR) bacteria acquisition. We used administrative, clinical and bacteriological data from all 157,570 patients hospitalized for at least 48 h from January 1, 2010 to December 31, 2015 in a 654-bed university teaching hospital in Paris, France. Monthly computed CUSUM were evaluated for the detection of out-of-control situations, defined as incidence rates of acquired AMR bacterial colonization exceeding acceptable thresholds at the hospital and ward levels (based on six selected wards) for AMR bacteria overall and Extended-spectrum beta-lactamases Enterobacteriaceae (ESBL-E) and Methicillin-resistant Staphylococcus aureus (MRSA), specifically. During the study period, 1,403 samples of acquired AMR bacteria were identified including 1,129 ESBL-E and 151 MRSA. The incidence rate of acquired AMR bacteria was stable at the hospital and the wards level. When based on AMR bacteria overall, CUSUM alarms were triggered at the hospital level and at the ward level in four units. For ESBL-E, CUSUM tests generated alarms at the hospital level and for the same four wards, and for MRSA, CUSUM tests detected out-of-control situations in all the wards. The CUSUM approach appears complementary with hospital infection control strategies currently in practice and appears of interest in common practice as a simple tool for AMR surveillance.

Nosocomial infection and its molecular mechanisms of antibiotic resistance

Nosocomial infection is a kind of infection, which is spread in various hospital environments, and leads to many serious diseases (e.g. pneumonia, urinary tract infection, gastroenteritis, and puerperal fever), and causes higher mortality than community-acquired infection. Bacteria are predominant among all the nosocomial infection-associated pathogens, thus a large number of antibiotics, such as aminoglycosides, penicillins, cephalosporins, and carbapenems, are adopted in clinical treatment. However, in recent years antibiotic resistance quickly spreads worldwide and causes a critical threat to public health. The predominant bacteria include Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii. In these bacteria, resistance emerged from antibiotic resistant genes and many of those can be exchanged between bacteria. With technical advances, molecular mechanisms of resistance have been gradually unveiled. In this review, recent advances in knowledge about mechanisms by which (i) bacteria hydrolyze antibiotics (e.g. extended spectrum β-lactamases, (ii) AmpC β-lactamases, carbapenemases), (iii) avoid antibiotic targeting (e.g. mutated vanA and mecA genes), (iv) prevent antibiotic permeation (e.g. porin deficiency), or (v) excrete intracellular antibiotics (e.g. active efflux pump) are summarized.