Risk Factors for Bloodstream Infections due to Extended-spectrum β-lactamase-producing Escherichia coli

Predictors for onset of extended-spectrum beta-lactamase-producing Escherichia coli-induced bacteraemia: a systematic review and meta-analysis

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli bacteraemia can induce unfavourable clinical outcomes due to delay in appropriate antimicrobial treatment and limited therapeutic options. Therefore, elucidating the predictors of ESBL-producing E. coli-induced bacteraemia is crucial to improve clinical outcomes. However, a literature search did not reveal any studies that incorporate a meta-analysis of the predictors of ESBL-producing E. coli-induced bacteraemia. As such, this review was undertaken to assess current evidence on the predictors of ESBL-producing E. coli-induced bacteraemia. PubMed, Web of Science and Cochrane Library databases were searched for all relevant publications from January 2000 to September 2021. This systematic review evaluated 10 observational studies, comprising a total of 2325 patients with E. coli-induced bacteraemia and 850 (36.6%) ESBL-producing strains. In the meta-analysis, previous antibiotic therapy [pooled risk ratio (RR) 2.72; P<0.001], especially with cephalosporins (pooled RR 4.66; P<0.001) and quinolones (pooled RR 5.47; P<0.001), and urinary catheter use (pooled RR 3.79; P<0.001) were predictive of ESBL-producing E. coli-induced bacteraemia. Antibiotic therapy for patients with the above-mentioned risk factors should be selected considering the possibility of ESBL-producing E. coli-induced bacteraemia compared with non-ESBL-producing E. coli-induced bacteraemia. It is important to elucidate whether appropriate modulation of the identified risk factors can potentially mitigate the risk of ESBL-producing E. coli-induced bacteraemia compared with non-ESBL-producing E. coli-induced bacteraemia.

Risk Factors for Bloodstream Infections Due to ESBL-Producing Escherichia coli, Klebsiella spp., and Proteus mirabilis

(1) Background: Risk factors for extended-spectrum beta-lactamase (ESBL) infections could vary geographically. The purpose of this study was to identify local risk factors for ESBL production in patients with Gram-negative bacteremia. (2) Methods: This retrospective observational study included adult patients admitted from January 2019 to July 2021 and had positive blood cultures for E. coli, K. pneumoniae, K. oxytoca, and P. mirabilis. Patients with ESBL infection were matched to a non-ESBL-producing infection with the same organism. (3) Results: A total of 150 patients were included: 50 in the ESBL group and 100 in the non-ESBL group. Patients in the ESBL group had a longer length of stay (11 vs. 7 days, p < 0.001), but not increased mortality (14% vs. 15%, p = 0.87) Multivariate analysis identified the receipt of >1 antibiotic in the last 90 days as a risk factor for ESBL infection (OR = 3.448, 95% CI = 1.494-7.957; p = 0.004); (4) Conclusions: Recent antimicrobial use was identified as an independent risk factors for ESBL-producing Enterobacterales infections. Knowledge of this risk may improve empirical therapy and reduce inappropriate use.

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.

Factors Associated with Extended-spectrum β-lactamase-producing Enterobacteria Isolated from Respiratory Samples

Objective Although extended-spectrum β-lactamase (ESBL)-producing bacteria are a global threat, as they may cause respiratory infection, the factors associated with the isolation of these bacteria from sputum remain unclear. We therefore explored the factors related to ESBL-producing Klebsiella pneumoniae and Escherichia coli isolated from sputum samples. Patients and Methods This study included consecutive patients admitted to our department from 2010 to 2021 with K. pneumoniae or E. coli isolated from their sputum. The patients were categorized into ESBL-producing and non-ESBL-producing groups, and the factors associated with ESBL-producing bacteria isolation were assessed using a binomial logistic regression analysis. Results We included 82 patients, and ESBL-producing pathogens were isolated from 23 (28%). The usage rates of cephem [odds ratio (OR) 4.000, 95% confidence interval (CI) 1.402-11.409, p=0.010], quinolone (OR 2.961, 95% CI 1.097-7.996, p=0.032), and macrolide (OR 4.273, 95% CI 1.518-12.028, p=0.006) in the past year were significantly higher in the ESBL-producing group than in the non-ESBL-producing group. The multivariate analysis revealed that the applications of cephem (adjusted OR: 4.130, 95% CI: 1.233-13.830, p=0.021) and macrolide (adjusted OR: 6.365, 95% CI: 1.922-21.077, p=0.002) was independently associated with the isolation of ESBL-producing bacteria. Conclusions A history of cephem and macrolide use can be considered a risk factor for ESBL-producing bacteria isolation from sputum samples. Physicians need to consider these risk factors when determining antibiotics for the treatment of patients with respiratory infections.

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.

Economic Burden of Patients with Bloodstream Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli

Background

The prevalence of infections with extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is increasing worldwide, but the economic impact of ESBL-EC bloodstream infection (BSI) has not been comprehensively evaluated.

Patients and Methods

A retrospective cohort including patients hospitalized at a tertiary hospital between January 2013 and December 2016 who were confirmed with a BSI of ESBL-EC or non-ESBL-EC was set. Clinical data and medical costs were collected by chart review of electronic and paper medical records. The economic burden was evaluated with disability-adjusted life years (DALYs).

Results

A total of 580 patients with E. coli BSI, comprising 333 patients (57.4%) with ESBL-EC BSI and 247 patients (42.6%) with non-ESBL-EC BSI, were identified. There were no significant differences in comorbidity and severity of patients between ESBL-EC and non-ESBL-EC BSI. The median length of stay (LOS) after bacteremia was 12 days for ESBL-EC (interquartile range, 7 to 21) versus 11 days for non-ESBL-EC (interquartile range, 7 to 21) (P = 0.38), and appropriate empirical antimicrobial therapy occurred in 87.4% versus 89.9% (P = 0.353). The mortalities were 20.1% versus 17.4% (P = 0.41). Patients with ESBL-EC did not have significantly different in-hospital medical costs to those with non-ESBL-EC (median, $8048.68 vs $7476.84, respectively, with a difference of $571.84, P = 0.321). In the non-ESBL-EC group, 247 patients lost 531.05 DALYs in total, with an average of 2.15 DALYs per person, while in the ESBL-EC group, 333 patients lost 692.64 DALYs in total, with an average of 2.08 DALYs per person. There is no significant difference in average DALYs (P = 0.343).

Conclusion

In conclusion, patients with BSI due to ESBL-EC did not cost more than patients with BSI due to non-ESBL-EC. This phenomenon may be attributed to timely and effective antibiotic treatment, but the initial empiric therapy with second- or third-line antibiotics in non-ESBL-EC BSI should be corrected.

Bacteremia Caused by Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in Vientiane, Lao PDR: A 5-Year Study

Although there has been an increasing incidence of bacteremia caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) across South East Asia, there are sparse data from the Lao PDR, where laboratory capacity for antimicrobial resistance surveillance is limited. We, therefore, retrospectively reviewed bacteremia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae between 2010 and 2014 at Mahosot Hospital, Vientiane, Lao PDR. Clinical and laboratory data relating to all episodes of ESBL-E bacteremia were reviewed over the 5-year period and compared with non-ESBL-E bacteremia. Blood cultures positive for E. coli or K. pneumoniae were identified retrospectively from laboratory records. Clinical and laboratory data were extracted from research databases and case notes and analyzed using STATA. Between 2010 and 2014, we identified 360 patients with E. coli (n = 249) or K. pneumoniae (n = 111) bacteremia, representing 34.8% of all patients with clinically significant bacteremia. Seventy-two (20%) isolates produced ESBL; E. coli accounted for 15.3% (55/360) and K. pneumoniae for 4.7% (17/360), respectively. The incidence of ESBL-producing E. coli bacteremia rose during the study period. By multiple logistic analysis, reported antibiotic use in the previous week was significantly associated with ESBL positivity (P < 0.001, odds ratio 3.89). Although multiresistant, most ESBL-producing E. coli and K. pneumoniae remained susceptible to meropenem (65/65; 100%) and amikacin (64/65; 98.5%). We demonstrated an alarming increase in the incidence of ESBL-E as a cause of bacteremia in Vientiane during the study period. This has implications for empiric therapy of sepsis in Laos, and ongoing surveillance is essential.

A retrospective analysis of risk factors and outcomes in patients with extended-spectrum beta-lactamase-producing Escherichia coli bloodstream infections

OBJECTIVE

Risk factors and outcomes associated with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) bloodstream infections (BSI) are not yet fully understood.

METHODS

This was a retrospective analysis of patients with E. coli BSI treated over a 4-year period. The characteristics of bacteremia caused by ESBL-producing versus non-ESBL-producing E. coli were compared. Factors influencing mortality were also assessed.

RESULTS

Of 554 eligible patients, 58.9% developed ESBL-producing E. coli. Multivariate analysis showed that urinary tract infections, stomach tube catheterization, and prior cephalosporin exposure were independent risk factors for the emergence of ESBL-producing E. coli BSI. No significant differences in 30-day mortality were seen in patients with BSI caused by ESBL-producing or non-ESBL-producing E. coli (11.1% vs. 9.2%; P=0. 642). Factors independently associated with a higher risk of mortality were previous carbapenem exposure, high APACHE II score, and respiratory tract origin.

CONCLUSIONS

This study showed that prior UTIs and previous cephalosporin exposure represent significant risk factors for the development of ESBL-producing E. coli BSI. Previous carbapenem exposure, high APACHE II score, and a respiratory tract origin were seen to be independent mortality risk factors in patients with E. coli BSI.

Extended-spectrum β-lactamase-producing E. coli septicemia among rectal carriers in the ICU

The aim of this study was to identify risk factors for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E coli) bloodstream infection (BSI) among carriers hospitalized between March 2011 and June 2016 at the ICU of the West China Hospital.The cases were patients with at least 1 episode of ESBL-producing E coli BSI within 1 week after a positive rectal swab. Controls were selected randomly 1:2 among ESBL-producing E coli rectal carriers who did not develop BSI.Among 19,429 ICU patients, 9015 (46.4%) had a positive rectal swab for ESBL-producing E coli. Of them, 42 (0.5%) were diagnosed with ESBL-producing E coli BSI. The in-hospital mortality was higher for the BSI patients compared with controls (19.1% vs. 6.0%, P = .031). In the past 72 hours, patients in case group were more likely to use penicillin (odds ratio [OR] = 12.076; 95% confidence interval [CI]: 1.397-104.251, P = .02), cephalosporin (OR = 6.900; 95% CI: 1.493-31.852, P = .01), and carbapenem (OR = 5.422; 95% CI: 1.228-23.907, P = .03) as compared to patients in control group. Also, when compared to patients in control group, patients in case group were likely to stay for a longer time in ICU before positive rectal swab test (OR = 1.041, 95% CI: 1.009-1.075, P = .01) and have higher maximum body temperature before positive rectal swab (OR = 8.014; 95% CI: 2.408-26.620, P = .001).Bacteremia owing to ESBL-producing E coli was associated with high antimicrobial exposure, hospital stay, and maximum body temperature.

Impact of cephalosporin restriction on incidence of infections with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an endemic setting

Decreasing cephalosporin use was described as an effective intervention in decreasing the incidence of infections caused by Klebsiella pneumoniae harbouring extended-spectrum beta-lactamase (ESBLKP). Due to sustained increased levels of infections caused by ESBLKP, a multifaceted antibiotic stewardship intervention aimed to decrease cephalosporin use was carried out at a large medical unit of a teaching hospital. All cephalosporins except the first-generation were restricted and could only be prescribed after authorization by an infectious disease physician. The use of cephalosporins decreased significantly after intervention. The effect was most prominent for the third-generation cephalosporins (7.9-1.5 DDD/100 OBD). There was an increase in the consumption of piperacillin/tazobactam, carbapenems and fluoroquinolones. In contrast to our expectations the ESBLKP incidence increased, but the changes were not statistically significant. The intervention was successful in controlling the prescribing of cephalosporins, but had no impact on incidence of ESBLKP infections.

Antimicrobial resistance patterns, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients with hematological disease: A monocenter retrospective study in China

The aim of this retrospective analysis was to evaluate the antimicrobial resistance, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients in a single hematological center in China. A retrospective case-control study of 157 adult hematological patients with 168 episodes of E coli bacteremia was initiated from April 2012 to July 2015. Antimicrobial susceptibility as well as antimicrobial co-resistance rates were analyzed. Clinical features and outcomes were also studied. In addition, risk factors for septic shock and death were investigated. Among the 553 positive blood isolates during the study period, the prevalence of E coli was 33.3% and ESBL production strains represented 61.9% of those examined. In all the E coli strains isolated, 85.6% were multidrug-resistance (MDR), 2.4% were extensive drug resistance (XDR), and 6.0% were resistant to carbapenems. More MDR phenotype was noted in ESBL-EC strains (98.6% vs 62.8%, P<.001) and isolates from neutropenic patients (98.6% vs 62.8%, P < .001). In the antimicrobial susceptibility test, carbapenems and amikacin exhibited not only higher in vitro activity against E coli (94.0% and 92.0%, respectively), but lower co-resistance rates to other antibiotics. Carbapenem resistant strains retained full sensitivity to tigecycline and 60% to amikacin. Piperacillin/tazobatam was the third sensitive drug to both ESBL-EC (77.1%) and non-ESBL-EC (86.0%). In our series, 81.6% episodes received appropriate initial antibiotic treatment and no significant decrease in it was found in bacteremia due to ESBL E coli and patients with neutropenia, septic shock. Septic shock was noted in 15.5% patients and the overall 30-day mortality rate was 21.7%. Multivariate analysis revealed that induction chemotherapy (OR 2.126; 95% CI 1.624-11.332; P = .003) and polymicrobial infection (OR 3.628; 95% CI 1.065-21.219; P = .041) were risk factors for septic shock, whereas male (OR 2.223; 95% CI 1.132-12.022; P < .01) and septic shock (OR 52.359; 95% CI 19.951-292.690; P = .030) were risk factors for death.In the hematology department, ESBL-producing and MDR are widely prevalent in E coli bacteremia which is still a major life-threatening problem, especially for patients with septic shock. For empirical antimicrobial therapy, combination based on aminoglycoside, especially amikacin, will be helpful to increase the antimicrobial coverage against ESBL-EC while combining tigecycline with aminoglycoside should be considered for seriously carbapenem-resistant infectious patients.

Prevalence, risk factors and antimicrobial susceptibility pattern of extended spectrum β-lactamase-producing bacteria in a tertiary care hospital

BACKGROUND

The widespread misuse of antibiotics over the past several decades has been regarded as the contributing factor in the development of resistance toward them. Extended spectrum β-lactamases (ESBLs) are enzymes produced by certain bacteria that can make them resistant to certain antibiotics. Early detection of ESBL strains and judicious use of antibiotics and proper implementation of infection control strategies are essential to prevent the spread of this threat in the community. The study aimed at appraising the prevalence, risk factors and antimicrobial susceptibility pattern of ESBL-producing microorganisms.

METHODS

A prospective observational study was carried out in a tertiary care referral hospital located in Malappuram district of Kerala among inpatients with infection by ESBL-producing bacteria in order to estimate the prevalence, risk factors and their antibiotic susceptibility pattern.

RESULTS

Out of the total 1156 patients studied, 118 had confirmed diagnosis on the presence of ESBL-producing microorganisms. Overall, 9.79% of all samples growing Enterobacteriaceae yielded an ESBL producer. Out of the total isolates identified, 66.1% were urinary tract infections, 15.1% were respiratory tract infections, 14.4% were surgical site infections and the remaining constituted blood stream infections. The highest antimicrobial activity against ESBL-producing isolates was observed for meropenem.

CONCLUSIONS

High prevalence of ESBL-producing organisms is evident in the study setting implicating the necessity to report the ESBL production along with the routine sensitivity reports supplemented with control measures which can assist a clinician in prescribing appropriate antibiotics.

Antimicrobial susceptibility of clinical Enterobacteriaceae isolates at the emergency department in a regional hospital: A threat of extended spectrum beta-lactamase-producers among nursing home residents

BACKGROUND/PURPOSE

The prevalence of extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in nursing home residents has rarely been reported in Taiwan.

METHODS

A retrospective study was performed at medical wards of a district hospital at southern Taiwan between July 2009 and June 2011. Patients were included if they were older than 18 years, admitted via the emergency department, and their blood, sputum, or urine culture revealed the growth of Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis. From each patient only the first isolate from the infection site was included. Antimicrobial susceptibility was determined using the disc diffusion method.

RESULTS

Overall, 827 patients were included, with 354 (42.8%) coming from the community and 473 (57.2%) referred from a nursing home. Of the isolates acquired in nursing home, 45.5% (215/473) harbored ESBL. By contrast, 20.6% (73) of 354 isolates acquired in the community exhibited the ESBL production phenotype (p < 0.001). Of the isolates obtained from blood, urine, or sputum, 28.2% (37/131), 36.0% (208/578), or 36.4% (43/118) harbored ESBL, respectively, whereas 41% (211) of 515 E. coli isolates, 34.3% (72) of 210 K. pneumoniae, and 4.9% (5) of 102 P. mirabilis had ESBL. In general, the isolates from a nursing home or those with ESBL had lower antimicrobial susceptibility rates than those from the community or those without ESBL production. Only amikacin, piperacillin/tazobactam, ertapenem, and imipenem/meropenem were active against >90% Enterobacteriaceae isolates, irrespective of ESBL production.

CONCLUSION

ESBL production was common among clinical Enterobacteriaceae isolates, especially E. coli or those isolated from nursing home residents.

Risk factors for bloodstream infection caused by extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae: A focus on antimicrobials including cefepime

BACKGROUND

Extended-spectrum β-lactamase (ESBL)-producing pathogens represent increasing challenges to physicians because of rising prevalence, high mortality, and challenging treatment. Identifying high risks and early appropriate therapy is critical to favorable outcomes.

METHODS

This is a 5-year retrospective case-case-control study performed at the Detroit Medical Center on adult patients with bloodstream infection (BSI) caused by ESBL-producing and non-ESBL-producing Escherichia coli or Klebsiella pneumoniae, each compared with uninfected controls. Data were collected from December 2004-August 2009. Multivariate analysis was performed using logistic regression.

RESULTS

Participants included 103 patients with BSI caused by ESBL-producing pathogens and 79 patients with BSI caused by pathogens that did not produce ESBLs. The mean age of patients in the ESBL group was 67 years; of the patients, 51% were men, 77% were black, and 38% (n = 39) died in hospital. The mean age of patients in the non-ESBL group was 58 years; of the patients, 51% were men, 92% were black, and 22% (n = 17) died in hospital. On multivariate analysis, predictors of BSI caused by ESBL-producing pathogens included central venous catheter (odds ratio [OR], 29.4; 95% confidence interval [CI], 3.0-288.3), prior β-lactam-/β-lactamase-inhibitor therapy (OR, 28.1; 95% CI, 1.99-396.5), and prior cefepime therapy (OR, 22.7; 95% CI, 2.7-192.4). The only risk factor for BSI caused by non-ESBL-producing pathogens was urinary catheter insertion (OR, 18.2; 95% CI, 3.3-100.3).

CONCLUSION

Prior antimicrobial therapy, particularly with β-lactam, was the strongest unique risk factor for BSI caused by ESBL-producing E coli or K pneumoniae.

An outbreak of multi-drug resistant Escherichia coli urinary tract infection in an elderly population: a case-control study of risk factors

BACKGROUND

Prevention of infection due to multi-drug resistant organisms is particularly challenging because of the spread of resistant bacteria beyond hospitals into the community, including nursing homes. This study aimed to identify risk factors for the acquisition of a multidrug resistant (MDR) Escherichia coli in a local outbreak.

METHODS

Study participants were all aged over 65 years. Cases had the MDR E. coli isolated from a routine urine sample, and controls had a urine sample submitted to the laboratory in the same time period but the MDR E. coli was not isolated. Information from clinical records was used to identify risk factors both in the hospital and the community setting for acquisition of the MDR E. coli.

RESULTS

76 cases and 156 controls were identified and included in the study. In a multivariate analysis, risk factors statistically significantly associated with acquisition of the MDR E. coli were female gender (adjusted OR 3.2; 95 % confidence interval 1.5-6.9), level of care (high dependency OR 7.5; 2.2-25.7) compared with living independently), and in hospital prescription of antimicrobials to which the MDR E. coli was resistant (OR 5.6; 2.5-12.9).

CONCLUSIONS

The major risk factors for the acquisition of a MDR E. coli were found to be residence in a nursing home and in-hospital prescription of antimicrobials to which the MDR E. coli was resistant. This emphasises that prevention of transmission of MDROs within a community needs to involve both hospitals and also other healthcare organizations, in this case nursing homes.

Extended spectrum β-lactamase producers among nosocomial Enterobacteriaceae in Latin America

To review the epidemiology of nosocomial extended spectrum β-lactamase-producing Enterobacteriaceae in Latin America, a systematic search of the biomedical literature (PubMed) was performed for articles published since 2005. Rates of nosocomial infections caused by extended spectrum β-lactamase-producing Enterobacteriaceae in Latin America have increased since 2005. Up to 32% of Escherichia coli and up to 58% of Klebsiella pneumoniae isolates are extended spectrum β-lactamase-positive, rates that are higher than in other world regions. From a region-wide perspective, 11–25% of E. coli isolates and 45–53% of K. pneumoniae isolates were nonsusceptible to third-generation cephalosporins. At the country level, there was a wide range in Enterobacteriaceae resistance rates to third-generation cephalosporins, with especially high rates of resistance to E. coli in Guatemala, Honduras, and Mexico, and high resistance rates to Klebsiella spp. in Argentina, Brazil, Chile, Guatemala, Honduras, and Paraguay. Susceptibility of extended spectrum β-lactamase-producing Enterobacteriaceae to cefepime, fluoroquinolones, ampicillin/sulbactam, aminoglycosides, and piperacillin/tazobactam has also been compromised, leaving the carbapenems, tigecycline, and colistin as the only antibiotics with >90% susceptibility rates. There is a steady increase in the prevalence and types of extended spectrum β-lactamases produced by Enterobacteriaceae isolates in Latin American hospitals (particularly CTX-Ms), suggesting endemic conditions overlaid by clonal outbreaks. Appropriate treatment decisions and infection control strategies informed by surveillance of regional and local susceptibilities and mechanisms of resistance are required to mitigate this major public health concern.

Risk factors of community-onset urinary tract infections caused by plasmid-mediated AmpC β-lactamase-producing Enterobacteriaceae

BACKGROUND

The AmpC β-lactamase (AmpC)-producing Enterobacteriaceae emerged worldwide. This study was conducted to determine the risk factors of community-onset urinary tract infections (UTIs) caused by plasmid-mediated AmpC-producing Enterobacteriaceae.

METHODS

Patients who were diagnosed as community-onset UTIs caused by Enterobacteriaceae in a tertiary-care teaching hospital from December 2010 to January 2012 were included. Extended-spectrum β-lactamase (ESBL)-producing isolates were excluded. We identified plasmid-mediated AmpC-producing Enterobacteriaceae both phenotypically (by disk potentiation test and double-disk synergy test) and genotypically (by Multiplex polymerase chain reaction (PCR) assay). The demographic data, clinical characteristics, and risk factors of acquisition were described.

RESULTS

Among the 323 non-ESBL-producing Enterobacteriaceae identified in community-onset UTIs, 50 isolates were phenotypically positive for AmpC. Escherichia coli was the most common AmpC-producing organism (60%), followed by Klebsiella pneumonia (8%), and Enterobacter cloacae and Proteus mirabilis (6% for each species). The independent risk factors for acquisition of AmpC-producing Enterobacteriaceae included prior history of cerebral vascular accident [odds ratio (OR) = 2.014; 95% confidence interval (CI) = 1.007-4.031; p = 0.0048], and prior use of fluoroquinolones (OR = 4.049; 95% CI = 1.759-9.319; p = 0.001) and cephamycin (OR = 9.683; 95% CI = 2.007-45.135; p = 0.004). AmpC-producing isolates were multidrug resistant. Carbapenems, cefepime, and piperacillin/tazobactam had the best in vitro efficacy. The most commonly identified plasmid-mediated AmpC gene was bla(CIT), followed by bla(DHA)/bla(EBC), and bla(MOx).

CONCLUSION

For community-onset UTIs, AmpC-producing Enterobacteriaceae should be suspected in those with prior history of cerebral vascular accident and prior use of antimicrobials. To treat these multiple-resistant isolates, carbapenems, cefepime, and piperacillin/tazobactam may be considered.

Resistant gram-negative infections in the outpatient setting in Latin America

Latin America has a high rate of community-associated infections caused by multidrug-resistant Enterobacteriaceae relative to other world regions. A review of the literature over the last 10 years indicates that urinary tract infections (UTIs) by Escherichia coli, and intra-abdominal infections (IAIs) by E. coli and Klebsiella pneumoniae, were characterized by high rates of resistance to trimethoprim/sulfamethoxazole, quinolones, and second-generation cephalosporins, and by low levels of resistance to aminoglycosides, nitrofurantoin, and fosfomycin. In addition, preliminary data indicate an increase in IAIs by Enterobacteriaceae producing extended-spectrum β-lactamases, with reduced susceptibilities to third- and fourth-generation cephalosporins. Primary-care physicians in Latin America should recognize the public health threat associated with UTIs and IAIs by resistant Gram-negative bacteria. As the number of therapeutic options become limited, we recommend that antimicrobial prescribing be guided by infection severity, established patient risk factors for multidrug-resistant infections, acquaintance with local antimicrobial susceptibility data, and culture collection.

High prevalence of antibiotic-resistant bacterial infections among patients with cirrhosis at a US liver center

BACKGROUND & AIMS

There are limited data on the prevalence or predictors of antibiotic-resistant bacterial infections (AR-BI) in hospitalized patients with cirrhosis in North America. Exposure to systemic antibiotics is a risk factor for AR-BI; however, little is known about the effects of the increasingly used oral nonabsorbed antibiotics.

METHODS

We analyzed data from patients with cirrhosis and bacterial infections hospitalized in a liver unit at a US hospital between July 2009 and November 2010. Multivariate logistic regression was used to determine predictors of AR-BI. Data were analyzed on the first bacterial infection of each patient (n = 115), and a sensitivity analysis was performed on all infectious episodes per patient (n = 169).

RESULTS

Thirty percent of infections were nosocomial. Urinary tract infections (32%) and spontaneous bacterial peritonitis (24%) were most common. Of the 70 culture-positive infections, 33 (47%) were found to be antibiotic resistant (12 were vancomycin-resistant Enterococci, 9 were extended-spectrum β-lactamase-producing Enterobacteriaceae, 7 were quinolone-resistant gram-negative rods, and 5 were methicillin-resistant Staphylococcus aureus). Exposure to systemic antibiotics within 30 days before infection was associated independently with AR-BI, with an odds ratio (OR) of 13.5 (95% confidence interval [CI], 2.6-71.6). Exposure to only nonabsorbed antibiotics (rifaximin) was not associated with AR-BI (OR, 0.4; 95% CI, 0.04-2.8). In a sensitivity analysis, exposure to systemic antibiotics within 30 days before infection and nosocomial infection was associated with AR-BI (OR, 5.2; 95% CI, 1.5-17.7; and OR, 4.2; 95% CI, 1.4-12.5, respectively).

CONCLUSIONS

The prevalence of AR-BI is high in a US tertiary care transplant center. Exposure to systemic antibiotics within 30 days before infection (including those used for prophylaxis of spontaneous bacterial peritonitis), but not oral nonabsorbed antibiotics, is associated with development of an AR-BI.

Detecting risk and predicting patient mortality in patients with extended-spectrum β-lactamase-producing Enterobacteriaceae bloodstream infections

Extended-spectrum β-lactamases (ESBLs) have been increasingly described worldwide, especially among Enterobacteriaceae isolates, and recently not only in the nosocomial, but also in the community setting. Bloodstream infections (BSIs) caused by ESBL-producing Enterobacteriaceae have been associated with increased rates of treatment failure, mortality and hospital costs. Any delay in the initiation of adequate antibiotic therapy is potentially lethal for patients with BSIs caused by ESBL-producing Enterobacteriaceae. The awareness of changes in bacterial resistance patterns, the careful knowledge of risk factors for ESBL infection and of factors facilitating adverse outcome, giving attention to local epidemiology, can improve the efficacy of empirical treatment protocols. The aim of this review is to focus on the main characteristics of BSIs caused by ESBL-producing Enterobacteriaceae, with particular emphasis on risk factors for these infections and factors related to mortality.

Complexity of β-lactamases among clinical Aeromonas isolates and its clinical implications

Aeromonas species, aquatic Gram-negative bacilli, distributed globally and ubiquitously in the natural environment, may be implicated in a variety of human diseases. They can produce various β-lactamases which confer resistance to a broad spectrum of β-lactams, and therefore in vitro susceptibility testing must be used to guide antimicrobial therapy. However, conventional in vitro susceptibility tests may sometimes fail to detect these β-lactamases, and hence raise a therapeutic challenge. In this review article, two chromosomally mediated β-lactamases (i.e., AmpC β-lactamases and metallo-β-lactamases) and acquired extended-spectrum β-lactamases in aeromonads are reviewed, and the clinical implications of the complexity of β-lactamases are discussed.

Impact of ceftriaxone de-restriction on the occurrence of ESBL-positive bacterial strains and antibiotic consumption

As a cost-saving measure, the Drug and Therapeutics Committee (DTC) removed ceftriaxone from the list of restricted antibiotics in May, 2008, which permitted its use as a first-line antibiotic. To evaluate the impact of this change, the occurrence of extended-spectrum beta-lactamase (ESBL)-positive bacterial strains and antibiotic consumption were monitored for 2 years before and after the intervention. In the post-intervention period, ceftriaxone utilization increased, while total antibiotic utilization did not change significantly. The utilization of all restricted antibiotics decreased (p <0.05) in the post-intervention period. Utilization of carbapenems increased (p <0.05), while utilization of quinolones increased nonsignificantly. The density of resistant ESBLs increased (p = 0.001) from 0.99 to 1.34 per 1000 bed-days from the pre- to the postintervention period. Ceftriaxone use was significantly correlated with ESBL occurrence (p <0.005). It can be concluded that ceftriaxone de-restriction increased the occurrence of ESBLs and the utilization of carbapemens.

The clinical epidemiology and outcomes of bacteremic biliary tract infections caused by antimicrobial-resistant pathogens

OBJECTIVES

The prevalence of antibiotic-resistant pathogens continues to increase steadily. The aim of this study was to analyze the changing patterns and risk factors of antibiotic resistance in patients with bacteremic biliary tract infections (BTIs). In addition, prognostic factors related to survival in patients with a bacteremic BTI were evaluated.

METHODS

Five hundred fifty-six biliary bacteremic events in 411 patients, treated from January 2000 to April 2010, were retrospectively analyzed. In addition, biliary bacteremic events were divided into nosocomial infections (N=396) and community-acquired infections (N=160).

RESULTS

The resistance rate to third-generation cephalosporin was higher in 2005-2009 (35 out of 140, 25%, vs. 72 out of 151, 47.7%). The prevalence of extended-spectrum β-lactamase-producing organisms of Escherichia coli and Klebsiella strains increased markedly from 2.3% (2 out of 86) in 2000-2004 to 43.9% (58 out of 132) in 2005-2009. Nosocomial infection, hospital days before bacteremia, previous hospitalization within 90 days, previous use of antibiotics within 90 days, and an indwelling biliary drainage catheter were found to be independently associated with antibiotic resistance. However, no association was found between antibiotic resistance and mortality in patients with biliary bacteremia.

CONCLUSIONS

Antibiotic resistance in bacteremic BTI has increased markedly during the past 10 years. Almost half of nosocomial bacteremic BTI caused by common Gram-negative pathogens during 2005-2009 (58.5%) could not be treated with third-generation cephalosporin. Clinical outcomes were found to be associated with bacteremia severity and underlying illness rather than antibiotic resistance.

Patient's origin and lifestyle associated with CTX-M-producing Escherichia coli: a case-control-control study

Background

Global dissemination of Escherichia coli producing CTX-M extended-spectrum β-lactamases (ESBL) is a public health concern. The aim of the study was to determine factors associated with CTX-M- producing E. coli infections among patients hospitalised in the Assistance Publique-Hôpitaux de Paris, the largest hospital system in France (23 000 beds), through a prospective case-control-control study.

Methods/Principal Findings

From November 2008 to June 2009, 152 inpatients with a clinical sample positive for CTX-M-producing E. coli (cases), 152 inpatients with a clinical sample positive for non ESBL-producing E. coli on the day or within the three days following case detection (controls C1), and 152 inpatients with culture-negative clinical samples since the beginning of hospitalisation and until three days after case detection (controls C2) were included in ten hospitals of the Paris area. Factors studied were related to patient's origin, lifestyle and medical history as well as care during hospitalisation. Those independently associated with CTX-M-producing E. coli were determined. Three independent factors were common to the two case-control comparisons: birth outside of Europe (cases vs C1: OR₁ = 2.4; 95%CI = [1.3–4.5] and cases vs C2: OR₂ = 3.1; 95%CI = [1.4–7.0]), chronic infections (OR₁ = 2.9; 95%CI = [1.3–6.9] and OR₂ = 8.7; 95%CI = [2.0–39.7]), and antibiotic treatment between hospital admission and inclusion (OR₁ = 2.0; 95%CI = [1.0–3.8] and OR₂ = 3.3; 95%CI = [1.5–7.2]). Cases were also more likely to be (i) functionally dependent before hospitalisation than C2 (OR₂ = 7.0; 95%CI = [2.1–23.5]) and (ii) living in collective housing before hospitalisation than C2 (OR₂ = 15.2; 95%CI = [1.8–130.7]) when CTX-M-producing E. coli was present at admission.

Conclusion

For the first time, patient's origin and lifestyle were demonstrated to be independently associated with isolation of CTX-M-producing E. coli, in addition to health care-related factors.