Extended-spectrum β-lactamase-producing Escherichia coli bacteremia: Comparison of pediatric and adult populations

Characterization of young infants with fecal carriage of multidrug-resistant Escherichia coli in Southern Taiwan

BACKGROUND

The accelerating prevalence of extended-spectrum β-lactamase (ESBL)-producing and multidrug-resistance (MDR) Escherichia coli(E. coli) become a public health challenge worldwide. This study aimed to discuss the prevalence of drug-resistant E. coli colonization and analyze its risk factors and clinical characteristics among young infants in Southern Taiwan.

METHODS

Stool samples were collected from young infants, aged less than three months, within three days of their hospitalization from September to December 2019 in a tertiary hospital. A questionnaire was designed for parents to complete. E. coli colonies were selected and analyzed for antimicrobial susceptibility. PCR-based multilocus sequence typing was to detect the presence of sequence type ST131 and blaCTX-M genes.

RESULTS

Among 100 enrolled infants, 36% had fecal carriage of E. coli isolates, of which twenty nine (80.5%) were MDR, thirteen (36.1%) were ESBL-producing isolates and five (13.8%) and ten (27.7%) were ST131 and strains carrying CTX-M-14 gene, respectively. Compared to non-ST131 and non-CTX-M-14 gene carrier, isolates of ST131 and CTX-M-14 gene carrier showed a significantly higher resistance rate to cefixime, ceftriaxone, and gentamycin, with p value all <0.05.

CONCLUSION

The prevalence of ESBL-producing and MDR E. coli fecal carriage were both high in young infants. The most common sequence type is ST131, of which all are strains carrying CTX-M-14. Further surveillance and investigation to control for the high prevalence of antimicrobial-resistant E. coli fecal carriage among infants in Taiwan are warranted.

High carriage rate of extended-spectrum β-lactamase Enterobacterales and diarrheagenic Escherichia coli in healthy donor screening for fecal microbiota transplantation

The safety of fecal microbiota transplantation (FMT) has been highlighted by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli bacteremia transmitted from donors and acquisition of diarrheagenic E. coli (Shiga toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC)) via FMT. The use of donor screening criteria to lower the risk of pathogen transmission via FMT is essential. This study aimed to demonstrate the outcomes of our strict donor screening program. This study was conducted at our FMT center between January 2019 and June 2022. Our donor screening program included an initial questionnaire and subsequent blood and stool testing. We further used selective culture for third-generation cephalosporin-resistant (3GCR) Enterobacterales and multiplex PCR to detect diarrheagenic E. coli in stools. The resistance mechanisms and sequence type of 3GCR Enterobacterales were determined. A total of 742 individuals were assessed, and 583 participants (78.6%) were excluded after questionnaire. Of the remaining 159 participants undergoing stool and blood tests, 37 participants were finally qualified (5.0%, 37/742). A high fecal carriage rate of ESBL-producing Enterobacterales (35.2%, 56/159), including E. coli (n=53) and Klebsiella pneumoniae (n=5), and diarrheagenic E. coli (31.4%, 50/159), including EPEC (n=41), enteroaggregative E. coli (n=11), enterotoxigenic E. coli (n=4), and STEC (n=1), was noted. CTX-M-79 and CTX-M-15 were dominant in E. coli and K. pneumoniae, respectively. The sequence types of the ESBL-producing strains were diverse. The screening for 3GCR Enterobacterales and diarrheagenic E. coli in stool is necessary. Our findings also support the effectiveness of multiplex PCR panels in FMT donor screening programs.

Epidemiology of extended-spectrum β-lactamases in Enterobacterales in Taiwan for over two decades

The emergence of antimicrobial resistance among microorganisms is a serious public health concern, and extended-spectrum β-lactamases (ESBL)-producing Enterobacterales is one of the major concerns among antibiotic-resistant bacteria. Although the prevalence of ESBL in Enterobacterales has been increasing with time, the prevalence of ESBL could differ according to the species, hospital allocation, sources of infections, nosocomial or community acquisitions, and geographic regions. Therefore, we conducted a comprehensive review of the epidemiology of ESBL-producing Enterobacterales in Taiwan. Overall, the rates of ESBL producers are higher in northern regions than in other parts of Taiwan. In addition, the genotypes of ESBL vary according to different Enterobacterales. SHV-type ESBLs (SHV-5 and SHV-12) were the major types of Enterobacter cloacae complex, but Serratia marcescens, Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae were more likely to possess CTX-M-type ESBLs (CTX-M-3 and CTX-M-14). Moreover, a clonal sequence type of O25b-ST131 has been emerging among urinary or bloodstream E. coli isolates in the community in Taiwan, and this clone was potentially associated with virulence, ESBL (CTX-M-15) production, ciprofloxacin resistance, and mortality. Finally, the evolution of the genetic traits of the ESBL-producing Enterobacterales isolates helps us confirm the interhospital and intrahospital clonal dissemination in several regions of Taiwan. In conclusion, continuous surveillance in the investigation of ESBL production among Enterobacterales is needed to establish its long-term epidemiology.

Distribution of microbes and antimicrobial susceptibility in patients with diabetic foot infections in South China

BACKGROUND

To investigate the distribution of microbes and drug susceptibility in patients with diabetic foot infections (DFI) and provide guidance for clinical empirical treatment and the rational selection of antibacterial drugs.

METHODS

Retrospective analysis of the pathogenic bacterium distribution and antimicrobial susceptibility isolated from 581 DFI patients with different Wagner grades.

RESULTS

The 534 positive samples included 473 cases (88.58%)) of monomicrobial infections and 61 cases (11.42%) of polymicrobial infections before antibiotic therapy. A total of 656 strains were cultivated, including 387 (58.99%) strains of gram-positive organisms (GPOs), 235 (35.82%) gram-negative bacilli (GNB), and 21 (3.20%) fungal strains. Polymicrobial infections mainly occurred in patients with Wagner grade 3-4 ulcers. GPOs were predominant in Wagner grades 1-3 (grade 1: 96.67%, grade 2: 76.52%, grade 3 62.81%), and the most common was Staphylococcus aureus (grade 1: 31.66%, grade 2: 33.04%, grade 3 35.53%). GNB were predominant in grades 4-5 (grade 4: 51.46%, grade 5:60%), and the most common GNB in Wagner grades 4-5 was Proteus (grade 4:27.88%, grade 5: 42.86%), while the most common GPO was Enterococcus (grade 4:34.48%, grade 5:25.00%). Staphylococcus (including MRSA) and Enterococcus were still highly sensitive to vancomycin, linezolid, and tigecycline. Most GNB were still highly sensitive to meropenem, tigecycline, ertapenem, and amikacin. Proteus was most sensitive to amikacin (97.14%), followed by meropenem (92%) and ertapenem (80%).

CONCLUSION

The distribution of microbes and antimicrobial susceptibility in DFI patients varied with different Wagner grades. The most appropriate antimicrobial therapy should be selected based on the pathogen culture and antimicrobial susceptibility.

Phylogeny and antimicrobial resistance of extended-spectrum beta-lactamaseproducing Escherichia coli from hospitalized oncology patients in Perú

Introduction: Healthcare-associated infections are a public health problem due to the increased morbimortality of patients, especially those with risk factors such as immunosuppression due to oncological diseases. It is essential to determine the genetic diversity of the main microorganisms causing healthcare infections by combining traditional epidemiological surveillance and molecular epidemiology for better outbreak follow-up and early detection. Objective: To determine the phylogenetic group and antibiotic resistance of Escherichia coli isolated from hospitalized oncologic patients. Materials and methods: We conducted a cross-sectional study of 67 strains of ESBL-producing Escherichia coli to determine their phylogenetic group and described their antibiotic resistance profile, beta-lactam resistance genes, as well as the type of sample and the hospitalization areas from which they were recovered. Results: The most frequent phylogenetic group was B2 (36%); 57% of B2 strains were isolated from urine and 33% came from the urology department. Resistance to ciprofloxacin and gentamicin was 92% and 53%, respectively, and 79% of the strains had the blaCTX-M gene. A significant association (p<0.05) was found between the phylogenetic groups, ciprofloxacin resistance, and the age of the patients. Conclusion: The predominant E. coli phylogroup was B2. We evidenced high resistance to ciprofloxacin and gentamicin, a high proportion of ESBL strains with the blaCTX-M gene, and a significant association between the phylogenetic group and the resistance to ciprofloxacin.

Distribution and Genomic Characterization of Third-Generation Cephalosporin-Resistant Escherichia coli Isolated from A Single Family and Home Environment: A 2-Year Longitudinal Study

Third-generation cephalosporin-resistant Escherichia coli (CREC), particularly strains producing extended-spectrum β-lactamases (ESBLs), are a global concern. Our study aims to longitudinally assemble the genomic characteristics of CREC isolates from fecal samples from an index patient with recurrent CREC-related urinary tract infections and his family and swabs from his home environment 12 times between 2019 and 2021 to investigate the distribution of antibiotic resistance genes. CREC identified using the VITEK 2 were subjected to nanopore whole-genome sequencing (WGS). The WGS of 27 CREC isolates discovered in 137 specimens (1 urine, 123 feces, and 13 environmental) revealed the predominance of ST101 and ST131. Among these sequence types, bla_CTX-M (44.4%, n = 12) was the predominant ESBL gene family, with bla_CTX-M-14 (n = 6) being the most common. The remaining 15 (55.6%) isolates harbored bla_CMY-2 genes and were clonally diverse. All E. coli isolated from the index patient’s initial urine and fecal samples belonged to O25b:H4-B2-ST131 and carried bla_CTX-M-14. The results of sequence analysis indicate plasmid-mediated household transmission of bla_CMY-2 or bla_CTX-M-55. A strong genomic similarity was discovered between fecal ESBL-producing E. coli and uropathogenic strains. Furthermore, bla_CMY-2 genes were widely distributed among the CREC isolated from family members and their home environment.

Prevalence and household risk factors for fecal carriage of ESBL-producing, sequence type 131, and extraintestinal pathogenic Escherichia coli among children in southern Taiwan

BACKGROUND

The rapidly increasing prevalence of antimicrobial-resistant Escherichia coli (E. coli) is a global concern. This study determined the prevalence and risk factors for the fecal carriage of drug-resistant E. coli and extraintestinal pathogenic E. coli (ExPEC) among children.

MATERIALS AND METHODS

In this prospective study, stool samples from children aged 0-18 years were obtained within three days of hospitalization between April 2016 and March 2019. E. coli were selected and tested for extended-spectrum β-lactamase (ESBL)-production and antimicrobial susceptibility. Multilocus sequence typing, blaCTX-M gene groups and ExPEC were determined using polymerase chain reactions. Questionnaires were recorded for risk factor analysis.

RESULTS

Among 179 E. coli isolates, 44.1% were multi-drug resistant, 20.7% produced ESBL, and 50.3% were ExPEC. Children carrying ESBL-producing E. coli were younger than those carrying non-ESBL strains. Several anthropogenic factors, including drinking water process, pork consumption, pets and household density might be associated with ESBL-producing E. coli, sequence type (ST) 131 E. coli, or ExPEC fecal carriage. Compared with families who live in less crowded houses, participants with pets had a similar trend of higher risks of ESBL-producing E. coli, ST131 E. coli, and ExPEC fecal carriage among those living in houses accommodating relatively more people.

CONCLUSIONS

Children accounted for a large proportion of instances of feces carrying ESBL E. coli. In addition to antimicrobial control for people and livestocks, avenues of exposure, such as drinking water, food, pets, household density, and socioeconomic deprivation might present potentially novel opportunities to reduce the burden of nonsusceptible E. coli and ExPEC.

Causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria

BACKGROUND

Jaundice may be one of the first signs of urinary tract infection (UTI) in infants. The most common pathogen is Escherichia coli. Currently recommended antibiotic treatment for neonatal UTI is ampicillin and an aminoglycoside. Recently, increasing ampicillin and gentamicin resistance in strains of E. coli has been isolated. The aim of this study was to determine causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria (SB).

METHODS

We evaluated admitted afebrile, asymptomatic infants younger than 1-month old with hyperbilirubinemia (total bilirubin >15 mg/dl) requiring phototherapy between January 2011 and December 2015. A total of 615 asymptomatic jaundiced infants were enrolled. Urinalysis and urine cultures were performed on all jaundiced infants. A urine culture was defined as SB if a single pathogen with more than 105-colony forming units per milliliter (CFU/ml) by sterile urinary collection bag or 104 CFU/ml by catheterization was isolated.

RESULTS

A total of 88 (14.3%) of 615 asymptomatic jaundiced infants had positive urinary culture. E coli was the most common cultured bacteria (40 cases, [45.5%]). Enterococcus faecalis was the second most common bacteria (17 cases, [19.3%]). Seven cases (8.0%) of Streptococcus agalactiae and six cases (6.8%) of Klebsiella pneumoniae were also identified. Ampicillin sensitivity was found in 22.5% of E. coli infections, gentamicin sensitivity was found in 84.2%, and extended-spectrum β-lactamases were found in 7.5%.

CONCLUSION

E. coli was the most common causative organism for infants with SB. We suggest modifying current empiric antibiotics by changing gentamicin to amikacin for neonatal Gram-negative bacterial infections.

Temporal Trend of ST131 Clone among Urinary Escherichia coli Isolates in the Community: A Taiwan National Surveillance from 2002 to 2016

Sequence type (ST) 131 is a multidrug-resistant pandemic lineage of E. coli responsible for extraintestinal infections. Few surveillance data of ST131 included all antimicrobial-susceptible and -resistant isolates or focused on community-acquired urinary tract infection (UTI). From a population-based surveillance pool of 2997 outpatient urine E. coli isolates, 542 were selected for detection of ST131 based on ciprofloxacin and/or cefotaxime resistance. Pulsed-field gel electrophoresis (PFGE) was performed on all ST131 isolates to further determine their relatedness. The estimated overall ST131 prevalence in this community UTI cohort increased from 11.2% (in 2002-2004), 12.2% (in 2006-2008), 13.6% (in 2010-2012), to 17.4% in 2014-2016 (p < 0.01). In the ciprofloxacin-resistant/cefotaxime-resistant group, ST131 increased from 33.3% in 2002-2004 to 72.1% in 2014-2016 (p < 0.01). In the ciprofloxacin-resistant/cefotaxime-susceptible group, ST131 was found in 24.3% overall without significant increase in its prevalence over time. PFGE showed emergence of a cluster of ciprofloxacin-resistant/cefotaxime-resistant ST131 carrying Gr. 1 CTX-M ESBL in 2014-2016, especially 2016. Multivariate analysis revealed that age (≥65 y.o) and ciprofloxacin resistance were independent factors associated with ST131. This longitudinal surveillance showed that ciprofloxacin-resistant/cefotaxime-susceptible ST131 has been circulating in the community since 2002 but ciprofloxacin-resistant/cefotaxime-resistant ST131 increased rapidly in the later years.

Bloodstream Infections Caused by Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Patients with Liver Cirrhosis

Background: This study aimed to investigate the frequency of sequence type (ST) 131 strains and outcome of cirrhotic patients with bloodstream infections (BSIs) caused by extended-spectrum beta-lactamase-producing Escherichiacoli (ESBLEC) and non-extended-spectrum beta-lactamase-producing Escherichiacoli (NESBLEC). Methods: The incidence of ST 131 strains, hospital stay, and 30-day re-admission/mortality were compared between 51 ESBLEC and 51 NESBLEC bacteremic patients with cirrhosis. Results: ST 131 strains were found in 35.3% of the ESBLEC group and 0% of the NESBLEC group (p < 0.001). Mean hospital stay was 26.5 days in the ESBLEC group and 17.1 days in the NESBLEC group (p = 0.006). Thirty-day re-admission rates were 11.8% in the ESBLEC group and 5.9% in the NESBLEC group (p = 0.5). ST 131 strains were associated with 30-day re-admission (odds ratio: 4.5, 95% confidence interval: 1.1–18.9). Thirty-day mortality rate was 31.4% in the ESBLEC group and 23.5% in the NESBLEC group (p = 0.4). Conclusion: In patients with cirrhosis, the ESBLEC BSIs group had a higher frequency of ST 131 strains and longer hospital stay than the NESBLEC BSIs group with similar 30-day re-admission/mortality. ST 131 strains were associated with 30-day re-admission.

National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored bla _KPC (n = 17), bla _OXA-48 (n = 2), and bla _VIM (n = 1) genes.

CTX-M group gene distribution of extended spectrum beta-lactamase-producing Enterobacteriaceae at a Japanese Children's hospital

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae have spread globally as one of the most common multidrug resistant organisms. Although a wide variety of ESBL genes were known in each geographical region, few reports existed on the distribution of ESBL genes in Japanese children. To clarify the distribution of ESBL genes, we investigated the CTX-M type of the ESBL-producing Enterobacteriaceae and patient characteristics among hospital-acquired and community-acquired cases. Total of 253 isolates of ESBL-producing Enterobacteriaceae were recovered from 238 pediatric patients. ESBL-producing Enterobacteriaceae were mostly recovered from children with underlying diseases (76.5%). Ratio of community-acquired and hospital-acquired cases was 58.8% and 41.2%, respectively. Compared to the hospital-acquired cases, community-acquired cases had younger age, fewer underlying diseases, and the dominant detection of Escherichia coli. The most common ESBL-producing Enterobacteriaceae was E. coli (79.8%), followed by Klebsiella pneumoniae (9.1%). CTX-M9 group was the most prevalent CTX-M group gene (63.2%), which was dominantly detected in E. coli (72.7%). This was the largest descriptive study to find CTX-M9 group as the most prevalent ESBL genotype among Enterobacteriaceae isolated from Japanese children in line with adult's epidemiology.

Tigecycline Therapy for Infections Caused by Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Critically Ill Patients

: We aimed to evaluate tigecycline on the clinical effectiveness in treating complicated skin and soft tissue infections (cSSTI), complicated intra-abdominal infections (cIAI), and pneumonia, caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, as data are limited. From three medical centers in Taiwan, we retrospectively studied the cSSTI, cIAI, and/or pneumonia caused by ESBL-producing Enterobacteriaceae. Among the 71 patients, including 39 patients infected with Klebsiella pneumoniae, 30 infected with Escherichia coli and others, the clinical success rate of tigecycline-based therapy was 80%-90% for pneumonia and cSSTI caused by E. coli and 50%-60% for cIAI caused by K. pneumoniae and E. coli. Microbiological and clinical outcome of pneumonia caused by carbapenem-resistant K. pneumoniae was poor. Univariate Cox analysis showed that dyspnea, SOFA score, septic shock, thrombocytopenia, prolonged prothrombin time, and lesser microbiological eradication were significant factors associated with 30-day mortality after the end of therapy. Cox regression proportional hazards model revealed dyspnea and a SOFA score > 8 to be independently associated with time to death. For ESBL producers, tigecycline showed good effects for cSSTI and pneumonia by E. coli, ordinary for cIAI, but ineffective for pneumonia by K. pneumoniae. Dyspnea and a high SOFA score predict a poor outcome.

Urinary Tract Infections With Extended-spectrum-β-lactamase-producing Bacteria: Case-control Study

BACKGROUND

Urinary tract infections (UTI) are the most common bacterial infections among infants and young children with fever without a source. Extended-spectrum β-lactamases (ESBLs) have emerged as emerging cause of UTI globally; however, data about risk factors and clinical features of children with ESBL-UTI have been scarce.

OBJECTIVE

To describe the predisposing risk factors, clinical and microbiologic features associated with pediatric UTIs caused by ESBL-producing bacteria (ESBL-PB).

METHODS

Our nested case-control study ran from January 1, 2012 to December 31, 2016. Pediatric patients with ESBL-PB UTI were compared with patients with non-ESBL-PB UTI matched for age and year of diagnosis.

RESULTS

A total of 720 children were enrolled (240 cases and 480 controls). Patients with ESBL-PB UTI were more likely to have a history of prior intensive care unit (ICU) admission (22.5% vs. 12.3%, P < 0.001), at least one underlying comorbidity (19.2% vs. 5.8%, P < 0.001), prior hospitalization (47.1% vs. 32.9%, P < 0.001), exposure to a cephalosporin antibiotic within 30 days before culture (7.5% vs. 4.2%, P = 0.035), and to have cystostomy (7.9% vs. 1.5%, P < 0.001) compared with those with non-ESBL-PB UTI. Patients with ESBL-PB UTI were more likely to present with hypothermia (48.8% vs. 38.5%, P = 0.009); had significantly longer average hospital stays {8.7 days [95% confidence interval (CI): 3.2-14.3] vs. 4.0 days (95% CI: 2.5-5.5)} and were more likely to be admitted to the ICU [odds ratio (OR) 1.8; 95% CI: 1.1-2.9). Multivariate analysis determined that only having cystostomy (OR 3.7; 95% CI: 1.4-9.4] and at least one underlying comorbidity (OR 2.4; 95% CI: 1.3-4.3) were the independent risk factors for ESBL-PB UTI. All ESBL-PB isolates tested against meropenem were susceptible, majority were resistant to multiple non-beta-lactam antibiotics.

CONCLUSIONS

Children with underlying comorbidities and cystostomy are at higher risk for ESBL-PB UTI, but majority of ESBL cases were patients without any known risk factors. Clinical signs/symptoms and commonly used biochemical markers were unreliable to differentiate cases caused by ESBL-PB from those caused by non-ESBL-PB. Further research is needed to elucidate the conditions most associated with ESBL-PB UTIs among children to properly guide empirical therapy in patients at-risk for these infections, to improve the outcomes, and finally, to determine strategies for rational antimicrobial use.

Applicability of an in-house saponin-based extraction method in Bruker Biotyper matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system for identifying bacterial and fungal species in positively flagged pediatric VersaTREK blood cultures

BACKGROUND/PURPOSE

Early identification of pathogens causing bloodstream infection (BSI) is critical for prompt administration of appropriate antimicrobial therapy.

METHODS

We used an in-house saponin-based extraction method to evaluate the performance of Bruker Biotyper MALDI-TOF MS system (MALDI Biotyper) for bacterial and fungal identification in 2013 positively-flagged VersaTREK blood culture bottles.

RESULTS

A total of 180 monomicrobial and 23 polymicrobial positive blood cultures were investigated. Among monomicrobial positive blood cultures, the MALDI Biotyper recognized 90.6% and 81.7% of organisms directly from the flagged blood culture bottles to the genus and species levels, respectively. The MALDI Biotyper also correctly characterized one of the polymicrobial organisms to the species level in 20 (87%) bottles and to the genus level in 21 (91.3%) bottles. The overall identification rate using our protocol was 90.6% (184/203) and 82.3% (167/203) for genus and species levels, respectively. Identification accuracy was higher for Gram-positive than Gram-negative organisms and was the lowest for yeasts. Score values of identification were ≥1.500 for 200 (98.5%) bottles, ≥1.700 for 195 (96.1%) bottles and ≥2.000 for 182 (89.7%) bottles. Moreover, 83.5% and 92% of the isolates were identified precisely to species and genus level with the lower cutoff score of 1.500. Using our protocol also helped identifying BSI pathogens 18-24 h earlier compared to the sub-cultured colonies.

CONCLUSION

Using Bruker MALDI Biotyper for identification of isolates directly from positive VersaTREK blood culture bottles, our in-house saponin-based protocol provided a more rapid turn-around time for correct identification of BSI pathogens than the conventional methods.

Available evidence of antibiotic resistance from extended-spectrum β-lactamase-producing Enterobacteriaceae in paediatric patients in 20 countries: a systematic review and meta-analysis

OBJECTIVE

To make a systematic review of risk factors, outcomes and prevalence of extended-spectrum β-lactamase-associated infection in children and young adults in South-East Asia and the Western Pacific.

METHODS

Up to June 2018 we searched online databases for published studies of infection with extended-spectrum β-lactamase-producing Enterobacteriaceae in individuals aged 0-21 years. We included case-control, cohort, cross-sectional and observational studies reporting patients positive and negative for these organisms. For the meta-analysis we used random-effects modelling of risk factors and outcomes for infection, and meta-regression for analysis of subgroups. We mapped the prevalence of these infections in 20 countries and areas using available surveillance data.

FINDINGS

Of 6665 articles scanned, we included 40 studies from 11 countries and areas in the meta-analysis. The pooled studies included 2411 samples testing positive and 2874 negative. A higher risk of infection with extended-spectrum β-lactamase-producing bacteria was associated with previous hospital care, notably intensive care unit stays (pooled odds ratio, OR: 6.5; 95% confidence interval, CI: 3.04 to 13.73); antibiotic exposure (OR: 4.8; 95% CI: 2.25 to 10.27); and certain co-existing conditions. Empirical antibiotic therapy was protective against infection (OR: 0.29; 95% CI: 0.11 to 0.79). Infected patients had longer hospital stays (26 days; 95% CI: 12.81 to 38.89) and higher risk of death (OR: 3.2; 95% CI: 1.82 to 5.80). The population prevalence of infection was high in these regions and surveillance data for children were scarce.

CONCLUSION

Antibiotic stewardship policies to prevent infection and encourage appropriate treatment are needed in South-East Asia and the Western Pacific.

Bloodstream infection with extended-spectrum beta-lactamase-producing Escherichia coli: The role of virulence genes

BACKGROUND

Extraintestinal pathogenic Escherichia coli (ExPEC) strains hold the responsibility for the majority of E. coli infections. Numerous extraintestinal virulence factors (VFs) were possessed by ExPEC which are involved in the pathogenesis of infection. However, the effect of comorbidities or infection syndrome in the association of VFs and mortality remains inconclusive.

METHOD

This study addressed whether specific sequence type (ST) and VFs of extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) are associated with different outcomes in patients with bloodstream infection. 121 adults from southern Taiwan with ESBL-EC bloodstream infections were enrolled during a 6-year period. Demographic data, including infection syndromes, underlying disease and outcomes, were collected. The virulence factors in isolates were analyzed by PCR and multilocus sequence typing analyses were also performed.

RESULT

Positivity for the virulence genes iha, hlyD, sat, iutA, fyuA, malX, ompT, and traT was associated with ST131 positivity (P < 0.05). Some ESBL-EC virulence genes associated with urinary tract infection (UTI) were revealed. Positivity for ST405 and the virulence genes iroN and iss were significantly associated with increased 30-day mortality (death within 30 days) on univariate analysis (P < 0.05). Independent risk factors of 30-day mortality in bacteremic patients with UTI included underlying chronic liver disease and malignancy. ST131 was borderline associated with 30-day mortality. Independent risk factors associated with 30-day mortality among bacteremic patients without UTI included comorbidities and iroN positivity.

CONCLUSION

In bacteremic patients with UTI, and the ST131 clone was borderline associated with mortality. Positivity for the virulence gene iroN may be linked to mortality in bacteremic patients without UTI.

Distribution of Microbes and Drug Susceptibility in Patients with Diabetic Foot Infections in Southwest China

OBJECTIVE

To investigate the microbial distribution and drug susceptibility among diabetic foot ulcers (DFUs) with different Wagner grades and between acute and chronic DFUs. Methods. We enrolled 428 DFU patients who were hospitalized and treated in the Southwest Hospital. We collected deep ulcer secretion for microbial culture and drug susceptibility tests and analyzed the results. We reexamined 67 patients with poor anti-infection efficacy and analyzed microbial species. Results: The 354 positive samples included 201 cases (56.8%) of single-pathogen infections and 153 cases (43.2%) of multiple-pathogen infections before antibiotic therapy. A total of 555 strains were cultivated, including 205 (36.9%) strains of gram-positive organisms (GPOs), 283 (51.0%) gram-negative bacilli (GNB), and 67 (12.1%) fungal strains. In terms of distribution, patients with different Wagner grades had different bacterial composition ratios (P < 0.01). Patients with Wagner grades 3-5 mainly had GNB. The specimens from chronic ulcer wounds were primarily GNB (54.2%), whereas fungi accounted for 14.4% of the infections; the distribution was significantly different from that of acute ulcers (P < 0.01). The susceptibility tests showed that the Staphylococcus genus was more susceptible to vancomycin, linezolid, and tigecycline. Tobramycin was the most effective drug (97%) for the treatment of Escherichia coli, followed by ertapenem (96.4%), imipenem (93.5%), and cefotetan (90%). Most of the remaining GNB were susceptible to antibiotics such as carbapenems, aminoglycosides, fluoroquinolones, ceftazidime, cefepime, and piperacillin-tazobactam (>63.2%). After antibiotic therapy, the positive rate of microbial culture was 52.2%, and the proportion of GNB and fungi increased to 68.9% and 20%.

CONCLUSION

The distribution and types of bacteria in diabetic foot infection (DFI) patients varied with the different Wagner classification grades, courses of the ulcers, and antibiotic therapy. Multidrug resistance were increased, and the clinical treatment of DFIs should select the most suitable antibiotics based on the pathogen culture and drug susceptibility test results.