Clinical and microbiologic characteristics of adult patients with recurrent bacteraemia caused by extended-spectrum β-lactamase-producing Escherichia coli or Klebsiella pneumoniae

Antimicrobial Resistance as Risk Factor for Recurrent Bacteremia after Staphylococcus aureus, Escherichia coli, or Klebsiella spp. Community-Onset Bacteremia

We investigated links between antimicrobial resistance in community-onset bacteremia and 1-year bacteremia recurrence by using the clinical data warehouse of Europe's largest university hospital group in France. We included adult patients hospitalized with an incident community-onset Staphylococcus aureus, Escherichia coli, or Klebsiella spp. bacteremia during 2017-2019. We assessed risk factors of 1-year recurrence using Fine-Gray regression models. Of the 3,617 patients included, 291 (8.0%) had >1 recurrence episode. Third-generation cephalosporin (3GC)-resistance was significantly associated with increased recurrence risk after incident Klebsiella spp. (hazard ratio 3.91 [95% CI 2.32-6.59]) or E. coli (hazard ratio 2.35 [95% CI 1.50-3.68]) bacteremia. Methicillin resistance in S. aureus bacteremia had no effect on recurrence risk. Although several underlying conditions and infection sources increased recurrence risk, 3GC-resistant Klebsiella spp. was associated with the greatest increase. These results demonstrate a new facet to illness induced by 3GC-resistant Klebsiella spp. and E. coli in the community setting.

Mortality, hospital length of stay, and recurrent bloodstream infections associated with extended-spectrum beta-lactamase-producing Escherichia coli in a low prevalence region: A 20-year population-based large cohort study

OBJECTIVES

This population-based study aimed to investigate the risk factors and effect of extended-spectrum beta-lactamase (ESBL) production on clinical outcomes in Escherichia coli bloodstream infection (BSI) patients.

METHODS

The study population was defined as patients aged ≥15 years with E. coli BSI in Queensland, Australia, from 2000 to 2019. Outcomes were defined as 30-day case fatality, hospital length of stay (LOS), and recurrent E. coli BSI.

RESULTS

A total of 27,796 E. coli BSIs were identified, of which 1112 (4.0%) were ESBL-producers. Patients with ESBL-Ec BSI were more frequently older, male, with comorbidity, recurrent E. coli BSI, and less likely with community-associated community-onset infections as compared to non-ESBL-Ec BSI patients. The standardized mortality rate of ESBL-Ec BSI increased 8-fold from 2000 to 2019 (1 to 8 per million residents) and case fatality was 12.8% (n = 142) at 30 days from positive blood culture. Patients with ESBL-Ec BSI were not at higher risk of 30-day case fatality (adjusted hazard ratio [HR] = 0.98, 95% CI: 0.83-1.17), but had higher risk of recurring episodes (adjusted subdistribution HR = 1.58, 95% CI: 1.29-1.92) and observed 14% longer LOS (adjusted incidence rate ratio = 1.14, 95% CI: 1.10-1.18) than non-ESBL-Ec BSI patients.

CONCLUSION

In this large patient cohort, ESBL-Ec BSI did not increase case fatality risk but observed higher hospital LOS and recurrent E. coli BSI than non-ESBL-Ec BSI. Clinical resources are warranted to account for the higher morbidity risk associated with ESBL production and incidence.

Clinical and Molecular Analyses of Recurrent Gram-Negative Bloodstream Infections

BACKGROUND

The causes and clinical characteristics of recurrent gram-negative bacterial bloodstream infections (GNB-BSI) are poorly understood.

METHODS

We used a cohort of patients with GNB-BSI to identify clinical characteristics, microbiology, and risk factors associated with recurrent GNB-BSI. Bacterial genotyping (pulsed-field gel electrophoresis [PFGE] and whole-genome sequencing [WGS]) was used to determine whether episodes were due to relapse or reinfection. Multivariable logistic regression was used to identify risk factors for recurrence.

RESULTS

Of the 1423 patients with GNB-BSI in this study, 60 (4%) had recurrent GNB-BSI. Non-White race (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.38-4.01; P = .002), admission to a surgical service (OR, 2.18; 95% CI, 1.26-3.75; P = .005), and indwelling cardiac device (OR, 2.73; 95% CI, 1.21-5.58; P = .009) were associated with increased risk for recurrent GNB-BSI. Among the 48 patients with recurrent GNB-BSI whose paired bloodstream isolates underwent genotyping, 63% were due to relapse (30 of 48) and 38% were due to reinfection (18 of 48) based on WGS. Compared with WGS, PFGE correctly differentiated relapse and reinfection in 98% (47 of 48) of cases. Median time to relapse and reinfection was similar (113 days; interquartile range [IQR], 35-222 vs 174 days; IQR, 69-599; P = .13). Presence of a cardiac device was associated with relapse (relapse: 7 of 27, 26%; nonrelapse: 65 of 988, 7%; P = .002).

CONCLUSIONS

In this study, recurrent GNB-BSI was most commonly due to relapse. PFGE accurately differentiated relapse from reinfection when compared with WGS. Cardiac device was a risk factor for relapse.

Carriage Duration and Household Transmission of Enterobacterales Producing Extended-Spectrum Beta-Lactamase in the Community: A Systematic Review and Meta-Analysis

An attributing factor to Enterobacterales producing extended-spectrum beta-lactamase (ESBL-E) community spread is human-to-human transmission. This systematic review and meta-analysis aimed to estimate the duration of ESBL-E carriage in the community and the rate of household transmission. Literature search was performed on PubMed, EMBASE, and Scopus. Dose-response meta-analysis was planned to model the proportion of ESBL-E carriers and household transmission over time. Twenty-six studies (n = 2,505 participants) were included. The median carriage duration was 2 months. Approximately 22% (95% confidence interval: 16-28) had persistent carriage after 12 months. Travelers had significantly shorter carriage (median 1-2 months) than discharged hospital patients (median 6 months) at all measured time points. There were insufficient data to robustly meta-analyze household transmission. Nonetheless, five longitudinal studies reported 18.4% to 35.2% of contacts acquired ESBL-E within 4 to 36 months from hospital discharge of index case. Transmission events from travelers to their contacts appeared lower. Travelers with travel-acquired ESBL-E had significantly faster decolonization rate than discharged patients, suggesting that travel-associated import of multidrug-resistant pathogen may have limited contribution to community transmission of ESBL-E. The substantial prevalence of persistent carriers warrant consideration for additional measures to mitigate exposure risk of ESBL-E from discharged patients in the community and from readmitting patients in the hospital.

Clinical and Microbiological Characteristics of Recurrent Escherichia coli Bacteremia

The causative agents of recurrent Escherichia coli bacteremia can be genetically identical or discordant, but the differences between them remain unclear. This study aimed to explore these differences, with regard to their clinical and microbiological features. Patients were recruited from a Japanese tertiary teaching hospital based on blood culture data and the incidence of recurrent E. coli bacteremia. We compared the patients' clinical and microbiological characteristics between the two groups (those with identical or discordant E. coli bacteremia) divided by the result of enterobacterial repetitive intergenic consensus PCR. Among 70 pairs of recurrent E. coli bacteremia strains, 49 pairs (70%) were genetically identical. Patients with genetically identical or discordant E. coli bacteremia were more likely to have renal failure or neoplasms, respectively. The virulence factor (VF) scores of genetically identical E. coli strains were significantly higher than those of genetically discordant strains, with the prevalence of eight VF genes being significantly higher in genetically identical E. coli strains. No significant differences were found between the two groups regarding antimicrobial susceptibility and biofilm formation potential. This study showed that genetically identical E. coli bacteremia strains have more VF genes than genetically discordant strains in recurrent E. coli bacteremia.

IMPORTANCEEscherichia coli causes bloodstream infection, although not all strains are pathogenic to humans. In some cases, this infection reoccurs, and several reports have described the clinical characteristics and/or molecular microbiology of recurrent Escherichia coli bacteremia. However, these studies focused on patients with specific characteristics, and they included cases caused by microorganisms other than Escherichia coli. Hence, little is known about the pathogenicity of Escherichia coli isolated from the recurrent one. The significance of our study is in evaluating the largest cohorts to date, as no cohort studies have been conducted on this topic.

Comparing success rates in central venous catheter salvage for catheter-related bloodstream infections in adult patients on home parenteral nutrition: a systematic review and meta-analysis

BACKGROUND

Catheter-related bloodstream infection (CRBSI) is a life-threatening complication of parenteral nutrition. Therefore, optimal management, ideally with catheter salvage, is required to maintain long-term venous access.

OBJECTIVES

We aimed to evaluate successful catheter salvage rates in patients on home parenteral nutrition (HPN).

METHODS

Studies were retrieved from medical databases, conference proceedings, and article reference lists. Data were collected relating to clinical outcomes of 3 treatments: systemic antibiotics, antimicrobial lock therapy (ALT), and catheter exchange. ORs and 95% CIs were calculated from a mixed logistic effects model.

RESULTS

From 10,036 identified publications, 28 met the inclusion criteria (22 cohort studies, 5 case-control studies, and 1 randomized clinical trial), resulting in a total of 4911 CRBSIs. To achieve successful catheter salvage, the addition of an antimicrobial lock solution was superior to systemic antibiotics alone (OR: 1.75; 95% CI: 1.21, 2.53; P = 0.003). Recurrence of infection was less common in studies that used ALT than in those that used systemic antibiotics alone (OR: 0.26; 95% CI: 0.11, 0.61; P = 0.002). The catheter exchange group was excluded from multilevel regression analysis because only 1 included study applied this treatment. Successful salvage rates were highest for coagulase-negative staphylococci, followed by Gram-negative rods and Staphylococcus aureus .

CONCLUSIONS

The addition of an antimicrobial lock solution seems beneficial for successful catheter salvage in HPN-dependent patients with a CRBSI. Future prospective randomized studies should identify the most effective and pathogen-specific strategy.This review was registered at www.crd.york.ac.uk/PROSPERO as CRD42018102959.

Preconceptual Priming Overrides Susceptibility to Escherichia coli Systemic Infection during Pregnancy

Maternal sepsis is a leading cause of morbidity and mortality during pregnancy. Escherichia coli is a primary cause of bacteremia in women and occurs more frequently during pregnancy. Several key outstanding questions remain regarding how to identify women at highest infection risk and how to boost immunity against E. coli infection during pregnancy. Here, we show that pregnancy-induced susceptibility to E. coli systemic infection extends to rodents as a model of human infection. Mice infected during pregnancy contain >100-fold-more recoverable bacteria in target tissues than nonpregnant controls. Infection leads to near complete fetal wastage that parallels placental plus congenital fetal invasion. Susceptibility in maternal tissues positively correlates with the number of concepti, suggesting important contributions by expanded placental-fetal target tissue. Remarkably, these pregnancy-induced susceptibility phenotypes are also efficiently overturned in mice with resolved sublethal infection prior to pregnancy. Preconceptual infection primes the accumulation of E. coli-specific IgG and IgM antibodies, and adoptive transfer of serum containing these antibodies to naive recipient mice protects against fetal wastage. Together, these results suggest that the lack of E. coli immunity may help discriminate individuals at risk during pregnancy, and that overriding susceptibility to E. coli prenatal infection by preconceptual priming is a potential strategy for boosting immunity in this physiological window of vulnerability.IMPORTANCE Pregnancy makes women especially vulnerable to infection. The most common cause of bloodstream infection during pregnancy is by a bacterium called Escherichia coli This bacterium is a very common cause of bloodstream infection, not just during pregnancy but in all individuals, from newborn babies to the elderly, probably because it is always present in our intestine and can intermittently invade through this mucosal barrier. We first show that pregnancy in animals also makes them more susceptible to E. coli bloodstream infection. This is important because many of the dominant factors likely to control differences in human infection susceptibility can be property controlled for only in animals. Despite this vulnerability induced by pregnancy, we also show that animals with resolved E. coli infection are protected against reinfection during pregnancy, including having resistance to most infection-induced pregnancy complications. Protection against reinfection is mediated by antibodies that can be measured in the blood. This information may help to explain why most women do not develop E. coli infection during pregnancy, enabling new approaches for identifying those at especially high risk of infection and strategies for preventing infection during pregnancy.

Characterisation of extended-spectrum β-lactamase/plasmid AmpC-β-lactamase-producing Escherichia coli isolates from long-term recurrent bloodstream infections

The aim of this study was to investigate recurrent infections in individual patients caused by extended-spectrum β-lactamase and plasmid AmpC β-lactamase-producing Escherichia coli (ESBL/pAmpC-Ec) isolates with >12-month interval. The Danish national collection of ESBL/pAmpC-Ec isolates collected from January 2014 through June 2017 was screened for patients with multiple isolates with >12 months between the episodes. Isolates underwent whole-genome sequencing and were analysed for antimicrobial resistance genes, virulence genes and multilocus sequence typing (MLST). Isolates were subtyped by core genome MLST (cgMLST) and CH typing. From a total of 970 patients, 15 unrelated patients experienced recurrent infections with ESBL/pAmpC-Ec. Of the 15 patients, 10 (67%) were found to be infected a second or third time with a genetically identical or similar strain. The resistance and virulence properties of the strains were similar in individual patients, however they were quite diverse when comparing between patients. Recurrent ESBL/pAmpC-Ec bloodstream infections of genetically related strains occurring with >12-month interval might be related to the previous episode and to a lesser extent be caused by re-infection. With >1000 days between the first and second episode of genetically similar strains (four allele differences), the recurrent infection is likely due to long-term host colonisation by ESBL/pAmpC-Ec. From this analysis, strains able to cause such recurrent infection were relatively diverse between patients. Knowledge about host and strain factors influencing such recurrent infections is needed to implement preventive measures.

Optimizing therapy of bloodstream infection due to extended-spectrum β-lactamase-producing Enterobacteriaceae

PURPOSE OF REVIEW

Infections due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are increasing worldwide. Carbapenems are usually regarded as the antibiotics of choice for the treatment of serious ESBL infections. However, because of the alarming emergence or carbapenem resistance, interest in effective alternatives has emerged. The present review summarizes the findings published on the antibiotics currently available for treatment of patients with an ESBL-E bloodstream infection (BSI).

RECENT FINDINGS

Meropenem and imipenem are the drugs recommended for treatment of ESBL BSIs in critically ill patients, and in infections with high bacterial loads or elevated β-lactam minimum inhibitory concentrations. Ertapenem should be reserved for patients with less severe presentations, and should be used at high doses. In milder presentations or BSIs from low-risk sources, other carbapenem-sparing alternatives could be considered: cephamycins, fluoroquinolones, and particularly a β-lactam/β-lactam inhibitor combination (particularly piperacillin/tazobactam). Optimized dosing of piperacillin/tazobactam is recommended (high doses and extended infusion). There are few data on the use of the promising newly available drugs (e.g. ceftolozane/tazobactam, ceftazidime/avibactam, cefiderocol, and plazomicin), and it seems reasonable to reserve them as last-resort drugs.

SUMMARY

Carbapenems should be used in patients with serious infections; alternatives could be used individually, particularly for definitive treatment of patients with milder presentations.

Extended spectrum β-lactamase producing enterobacteriaceae: carbapenem sparing options

Introduction: Carbapenems have an important place in our antibiotic armamentarium and have been trusted to effectively treat infections caused by ESBL-producing Enterobacteriaceae for many years. However, the utility of carbapenems has been compromised by the emergence of resistance especially in Enterobacteriaceae. Therefore, carbapenem-sparing alternative antibiotics are of extreme importance in clinical practice.Areas covered: We reviewed studies addressing currently available antibiotic options used as both empiric and definitive therapy for the treatment of infections due to ESBL-producing Enterobacteriaceae published in the PubMed/MEDLINE, Web of Science and Scopus databases without any date restriction. Current treatment alternatives included beta-lactam/beta-lactamase inhibitor combinations, cefepime, cephamycins, fluoroquinolones, aminoglycosides, fosfomycin, pivmecillinam, temocillin and, various oral alternative agents. We also summarized the clinical and molecular epidemiology, early prediction methods and impact of initial empirical therapy and de-escalation approach for ESBL-producing Enterobacteriaceae infections.Expert opinion: The current literature would endorse the carbapenem utilization for patients with severe and high inoculum-high risk infections. However, for milder infections particularly for urinary tract infections, various carbapenem-sparing antibiotics can be considered in selected cases. For infections including easily drainable intra-abdominal infections and catheter-related infections in which catheter removal is readily available more reliable data are needed to recommend non-carbapenem antibiotics confidently.

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.

Current options for the treatment of infections due to extended-spectrum beta-lactamase-producing Enterobacteriaceae in different groups of patients

BACKGROUND

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are a frequent cause of invasive infections worldwide. Carbapenems are nowadays the most used drugs to treat these infections. However, due to the increasing rates of resistance to these antimicrobials, carbapenem-sparing alternatives are being investigated.

OBJECTIVES AND SOURCES

The aim of this narrative literature review is to summarize the published information on the currently available antibiotics for the treatment of ESBL-E infections, providing specific information on three subgroups of patients: Group 1, patients with severe infections or infections from high-risk sources or in severely immunocompromised patients; Group 2, patients with non-severe infections from intermediate-risk source; and Group 3, patients with non-severe urinary tract infection.

CONTENT AND IMPLICATIONS

For patients in Group 1, the current data would support the use of carbapenems. For milder infections, however, particularly urinary tract infections, other non-carbapenem antibiotics can be considered in selected cases, including beta-lactam/beta-lactam inhibitor combinations, cephamycins, temocillin and aminoglycosides. While specific studies should be performed in these situations, individualized decisions may be taken in order to avoid overuse of carbapenems.

In vitro activity of flomoxef against extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Korea

To find an alternative regimen for the treatment of extended-spectrum β-lactamase (EBSL)-producing Enterobacteriaceae infections, we examined the in vitro activity of flomoxef against Escherichia coli and Klebsiella pneumoniae having CTX-M-1 group and/or CTX-M-9 group ESBLs. Boronic acid disk methods and polymerase chain reaction amplification were used to detect for ESBL, and AmpC β-lactamase and AmpC β-lactamase co-producers were excluded. Minimum inhibitory concentrations (MICs) were determined for flomoxef by broth microdilution. One hundred seventy-six isolates (E. coli, n = 93 and K. pneumoniae, n = 83) were analyzed for susceptibility test. A total of 94.3% (166/176) of isolates were susceptible to flomoxef (MIC₅₀/MIC₉₀ were 0.5/8 μg/mL); 98.9% of the ESBL-producing E. coli (MIC₅₀/MIC₉₀ were 1/4 μg/mL) and 89.2% of the ESBL-producing K. pneumoniae (MIC₅₀/MIC₉₀ were 0.5/16 μg/mL) were susceptible to flomoxef. Flomoxef has good in vitro activity against ESBL-producing E. coli and K. pneumoniae and could be considered as an alternative for infections caused by these organisms.

Clinical benefit of ertapenem compared to flomoxef for the treatment of cefotaxime-resistant Enterobacteriaceae bacteremia

Objectives

Cefotaxime-resistant Enterobacteriaceae (CE) infections are intractable, with limited treatment options. Though carbapenems are frequently prescribed for CE infections, the emergence of carbapenem-resistant Enterobacteriaceae is of huge concern. Flomoxef is effective against CE in vitro, and some clinical data on its demonstrated effectiveness against CE bloodstream infections (BSIs) exists.

Patients and methods

We conducted a retrospective study on adults with BSI caused by flomoxef-susceptible CE to investigate the efficacy of flomoxef compared with that of ertapenem. The outcome was evaluated with propensity score-based matching and logistic regression analysis.

Results

Demographic and clinical characteristics of patients treated with flomoxef (n = 58) or ertapenem (n = 188) were compared. In the multivariate analysis, severe sepsis (adjusted odds ratio [AOR] = 3.84; 95% confidence interval [CI], 1.16–12.78; p = 0.03), high BSI mortality score (AOR = 5.59; 95% CI, 2.37–13.21; p < 0.01), ultimately or rapidly fatal comorbidity (AOR = 10.60; 95% CI, 3.43–32.75; p < 0.01), and pneumonia (AOR = 10.11; 95% CI, 3.43–29.81; p < 0.01) were independently associated with 28-day mortality. Using propensity scores, 58 flomoxef-treated patients were matched to 116 ertapenem-treated patients. There were no intergroup differences in BSI severity, comorbidity, or BSI sources. The 28-day mortality rates (20.7% vs 13.8%, p = 0.28) did not differ significantly. However, hospitalization length was shorter in the ertapenem group (10.2 ± 8.5 vs. 14.6 ± 9.4 days, p < 0.01).

Conclusion

Although similar outcomes were observed between the groups, ertapenem therapy was associated with a shorter hospitalization time in adults after CE BSI.

Successful ceftazidime-avibactam treatment of MDR-KPC-positive Klebsiella pneumoniae infection in a patient with traumatic brain injury: A case report

RATIONALE

Carbapenem-resistant Enterobacteriaceae infections are a serious health care problem, because of the high mortality. Carbapenem resistance is mainly caused by carbapenemases production, including Klebsiella pneumoniae carbapenemase (KPC). Ceftazidime-avibactam is a new cephalosporin/β-lactamase inhibitor combination for the treatment of complicated urinary, intra-abdominal infections, and nosocomial pneumonia caused by gram negative, or other serious gram-negative infections.

PATIENT CONCERNS

We showed the case of a 27-year-old patient, hospitalized for traumatic brain injury and chest trauma, with KPC-producing Klebsiella pneumoniae infection.

DIAGNOSES

Blood and bronchial aspirate culture analysis detected an infection caused by MDR Klebsiella pneumoniae, resistant to meropenem, ertapenem, piperacillin/tazobactam, amoxicillin/clavulanic acid, aztreonam, ceftazidime, cefotaxime, cefepime, amikacin, ciprofloxacin, trimethoprim/sulfamethoxazole, colistin while it showed an intermediate sensitivity to gentamicin and was sensitive to ceftazidime-avibactam. Molecular analyses revealed that the isolate belonged to the epidemic clone sequence type 258 (ST258) carrying blaKPC-3, blaTEM-1, and blaSHV-11genes.

INTERVENTIONS

After various combined antibiotic therapies without improvements, he was treated with ceftazidime-avibactam, on a compassionate-use basis.

OUTCOMES

With ceftazidime-avibactam monotherapy clinical and microbiological clearance was obtained. A week after the end of the therapy microbiological analysis was repeated and a positive rectal swab for KPC-Klebsiella pneumoniae was found, becoming negative after 1 month. Moreover, the patient did not show any relapses for up to 18 weeks.

LESSONS

This case indicates that ceftazidime-avibactam monotherapy could be efficacious against KPC positive Klebsiella pneumoniae infections.

Antibiotic Prophylaxis Is Associated with Subsequent Resistant Infections in Children with an Initial Extended-Spectrum-Cephalosporin-Resistant Enterobacteriaceae Infection

The objective of this study was to assess the association between previous antibiotic use, particularly long-term prophylaxis, and the occurrence of subsequent resistant infections in children with index infections due to extended-spectrum-cephalosporin-resistant Enterobacteriaceae We also investigated the concordance of the index and subsequent isolates. Extended-spectrum-cephalosporin-resistant Escherichia coli and Klebsiella spp. isolated from normally sterile sites of patients aged <22 years were collected along with associated clinical data from four freestanding pediatric centers. Subsequent isolates were categorized as concordant if the species, resistance determinants, and fumC-fimH (E. coli) or tonB (Klebsiella pneumoniae) type were identical to those of the index isolate. In total, 323 patients had 396 resistant isolates; 45 (14%) patients had ≥1 subsequent resistant infection, totaling 73 subsequent resistant isolates. The median time between the index and first subsequent infections was 123 (interquartile range, 43 to 225) days. In multivariable Cox proportional hazards analyses, patients were 2.07 times as likely to have a subsequent resistant infection (95% confidence interval, 1.11 to 3.87) if they received prophylaxis in the 30 days prior to the index infection. In 26 (58%) patients, all subsequent isolates were concordant with their index isolate, and 7 (16%) additional patients had at least 1 concordant subsequent isolate. In 12 of 17 (71%) patients with E. coli sequence type 131 (ST131)-associated type 40-30, all subsequent isolates were concordant. Subsequent extended-spectrum-cephalosporin-resistant infections are relatively frequent and are most commonly due to bacterial strains concordant with the index isolate. Further study is needed to assess the role prophylaxis plays in these resistant infections.

Increased Costs Associated with Bloodstream Infections Caused by Multidrug-Resistant Gram-Negative Bacteria Are Due Primarily to Patients with Hospital-Acquired Infections

The clinical and economic impacts of bloodstream infections (BSI) due to multidrug-resistant (MDR) Gram-negative bacteria are incompletely understood. From 2009 to 2015, all adult inpatients with Gram-negative BSI at our institution were prospectively enrolled. MDR status was defined as resistance to ≥3 antibiotic classes. Clinical outcomes and inpatient costs associated with the MDR phenotype were identified. Among 891 unique patients with Gram-negative BSI, 292 (33%) were infected with MDR bacteria. In an adjusted analysis, only history of Gram-negative infection was associated with MDR BSI versus non-MDR BSI (odds ratio, 1.60; 95% confidence interval [CI], 1.19 to 2.16; P = 0.002). Patients with MDR BSI had increased BSI recurrence (1.7% [5/292] versus 0.2% [1/599]; P = 0.02) and longer hospital stay (median, 10.0 versus 8.0 days; P = 0.0005). Unadjusted rates of in-hospital mortality did not significantly differ between MDR (26.4% [77/292]) and non-MDR (21.7% [130/599]) groups (P = 0.12). Unadjusted mean costs were 1.62 times higher in MDR than in non-MDR BSI ($59,266 versus $36,452; P = 0.003). This finding persisted after adjustment for patient factors and appropriate empirical antibiotic therapy (means ratio, 1.18; 95% CI, 1.03 to 1.36; P = 0.01). Adjusted analysis of patient subpopulations revealed that the increased cost of MDR BSI occurred primarily among patients with hospital-acquired infections (MDR means ratio, 1.41; 95% CI, 1.10 to 1.82; P = 0.008). MDR Gram-negative BSI are associated with recurrent BSI, longer hospital stays, and increased mean inpatient costs. MDR BSI in patients with hospital-acquired infections primarily account for the increased cost.

Reinfection and relapse of recurrent bacteremia caused by Klebsiella pneumoniae in a medical center in Taiwan

AIM

To delineate the genetic relatedness of Klebsiella pneumoniae causing recurrent bacteremia.

MATERIALS & METHODS

Clinical characteristics of patients, distribution of capsular genoserotypes by capsular cps-PCR genotyping and the genetic relatedness of the paired isolates using arbitrarily primed PCR and pulsed-field gel electrophoresis were investigated.

RESULTS

Of 3067 patients with K. pneumoniae bacteremia, 129 (4.2%) had recurrent bacteremia (301 episodes). Of 129 patients with recurrent bacteremia, 51 (39.5%) were reinfected by the same strains (paired isolates with identical randomly amplified polymorphic DNA patterns and closely related pulsotypes). Multivariate analysis demonstrated that diabetes mellitus (odds ratio: 5.82; p < 0.001) and infection due to serotype K2 (odds ratio: 13.93; p < 0.001) were associated with relapse in patients with recurrent bacteremia.

CONCLUSION

Recurrent K. pneumoniae bacteremia could occur in patients with underlying hematological malignancies or suffering from primary bacteremia. Relapse infection is associated with serotype K2 strains and underlying diabetes mellitus.

ESBL Detection: Comparison of a Commercially Available Chromogenic Test for Third Generation Cephalosporine Resistance and Automated Susceptibility Testing in Enterobactericeae

Rapid detection and reporting of third generation cephalosporine resistance (3GC-R) and of extended spectrum betalactamases in Enterobacteriaceae (ESBL-E) is a diagnostic and therapeutic priority to avoid inefficacy of the initial antibiotic regimen. In this study we evaluated a commercially available chromogenic screen for 3GC-R as a predictive and/or confirmatory test for ESBL and AmpC activity in clinical and veterinary Enterobacteriaceae isolates. The test was highly reliable in the prediction of cefotaxime and cefpodoxime resistance, but there was no correlation with ceftazidime and piperacillin/tazobactam minimal inhibitory concentrations. All human and porcine ESBL-E tested were detected with exception of one genetically positive but phenotypically negative isolate. By contrast, AmpC detection rates lay below 30%. Notably, exclusion of piperacillin/tazobactam resistant, 3GC susceptible K1+ Klebsiella isolates increased the sensitivity and specificity of the test for ESBL detection. Our data further imply that in regions with low prevalence of AmpC and K1 positive E. coli strains chromogenic testing for 3GC-R can substitute for more time consuming ESBL confirmative testing in E. coli isolates tested positive by Phoenix or VITEK2 ESBL screen. We, therefore, suggest a diagnostic algorithm that distinguishes 3GC-R screening from primary culture and species-dependent confirmatory ESBL testing by βLACTATM and discuss the implications of MIC distribution results on the choice of antibiotic regimen.