Resistance against broad-spectrum beta-lactams among uropathogens in children

Antibiotic resistance pattern of uropathogenic Escherichia coli isolated from children with symptomatic urinary tract infection in Moscow, Russia

Background and Aim: Uropathogenic Escherichia coli (UPEC) is commonly involved in urinary tract infections (UTIs), which are generally treated with antibiotics. However, the emergence of multidrug-resistant (MDR) strains of UPEC has made the treatment difficult. There is thus a need to continuously assess their sensitivity to antibiotics. This study aimed to determine the antibiotic resistance patterns and MDR phenotypes of UPEC strains isolated from children diagnosed with UTIs at the Russian Children's Clinical Hospital in Moscow, Russia. Materials and Methods: Kirby–Bauer's disc diffusion method was used to study the sensitivity to antibiotics of 106 UPEC isolates from urine specimens from children (aged from 9 months to 18 years old) diagnosed with UTIs. The results were interpreted in accordance with the Clinical and Laboratory Standards Institute guidelines and the correlations of variables with the degree to which each antibiotic inhibited the UPEC strains in terms of diameter on the disc were determined using Spearman's rank correlation test. A t-test and principal component analysis were performed to visualize the correlations of the susceptibility of UPEC to antibiotics with the age and sex of the patients. Statistical significance was set at p≤0.05. Results: Among the 106 UPEC strains tested, none (0%) showed resistance to fosfomycin (FO), while 84 (79.2%) were resistant (R) to at least one antibiotic. The highest rates of resistance were observed to amoxicillin (69.8%), ampicillin (62.3%), cefazolin (39.6%), trimethoprim (TR) (37.7%), ceftriaxone (34.9%), and tetracycline (33.0%). Interestingly, 22 (20.8%) strains were R to imipenem. UPEC isolates from males aged 1-6 years were more R to antibiotics than those from the other groups, with the exception of TR, to which UPEC isolates from females aged 13-18 years old were less sensitive (S). The multidrug-resistance (MDR) index ranged between 0.00 and 0.75 and we found that more than a quarter of UPEC (31/106) had an MDR index ≥0.5 and only 22 (20.7%) strains were S to all antibiotics tested (MDR index=0). Finally, Spearman's rank correlation test showed that, with the exception of FO, there were correlations between the inhibition diameters of all other antibiotics. Conclusion: FO is the only antibiotic to which all UPECs were S and may be suggested as the first line of treatment for UPEC. Further research is needed to continue monitoring antibiotic resistance and to investigate the genetic features associated with such resistance observed in this study.

Multiresistant E. coli urine infections in children: a case-control study

OBJECTIVE

Urinary tract infections (UTIs) caused by resistant organisms are increasing which poses challenges when selecting empirical antimicrobial therapy. The aim of this study is to determine risk factors for multiresistant Escherichia coli UTIs in children.

DESIGN

We included all reported urinary isolates from a children's hospital collected between January 2010 and June 2013. Patients who had multiresistant E. coli UTIs were identified and a retrospective review of medical records performed. Patient-specific clinical and demographic factors were compared with age-matched and gender-matched controls with non-multiresistant E. coli UTIs. Univariable and multivariable statistical analysis were performed to determine significant risk factors for multiresistant organism E.coli UTIs.

RESULTS

In total, there were 2692 positive urine cultures, 1676 (62.3%) from 1169 patients were E. coli. Multiresistant E. coli was isolated from 139 (8.3% of all E. coli) cultures in 99 patients. Thirteen incomplete medical records were excluded, leaving 86 patients, matched with 86 controls. In multivariable regression, the only significant risk factor was antibiotic use in the previous month (adjusted OR 3.0, 95% CI 1.4 to 6.2), but not previous hospital admission (adjusted OR 1.4, 95% CI 0.6 to 2.9), being an inpatient at the time of diagnosis (adjusted OR 2.4, 95% CI 0.8 to 7.4) and previous instrumentation (adjusted OR 1.0, 95% CI 0.4 to 2.4).

CONCLUSIONS

This is the first case-control study to examine multiresistant UTI in Australian children. Clinicians should be judicious in the use of antibiotics in treatment and prophylaxis of UTIs. In children presenting with UTI and recent antibiotic exposure, amoxicillin-clavulanic acid appears to be an appropriate empiric antibiotic choice in our population.

A comparison of blood stream infections with extended spectrum beta-lactamase-producing and non-producing Klebsiella pneumoniae in pediatric patients

Background

Rapid development and global spread of multidrug resistant Klebsiella pneumonia (K. pneumoniae) as a major cause of nosocomial infections is really remarkable. The aim of this study was to explore risk factors for health care associated blood stream infections (BSI) caused by ESBL-producing K. pneumoniae in children and analyze clinical outcomes.

Methods

A retrospective review of patients younger than 18 years-old with blood stream infection caused by K. pneumoniae was performed. Patients with ESBL-producing K. pneumoniae isolates were compared with ESBL-non-producing isolates in terms of risk factors, outcome and mortality.

Results

Among 111 K. pneumoniae isolates 62% (n = 69) were ESBL –producing K. pneumoniae. The median total length of hospitalization and median length of stay in hospital before infection was significantly higher in patients with ESBL-producing isolates than ESBL-non-producing. Use of combined antimicrobial treatment was significantly different between ESBL-producing and ESBL-non-producing groups, 75.4% and 24.6%, respectively (p = 0.001). Previous aminoglycoside use was higher in cases with ESBL –producing isolates (p = 0.001). Logistic regression analysis showed a significant correlation between mortality and use of combined antibiotics (OR 4.22; p = 0.01).

Conclusion

ESBL production in K. pneumoniae isolates has a significant impact on clinical course of BSIs. Total length of hospitalization, length of hospital stay before infection, prior combined antibiotic use and use of aminoglycosides were significant risk factors for development of ESBL-producing K. pneumoniae related BSI.

Previous Antibiotic Exposure Increases Risk of Infection with Extended-Spectrum-β-Lactamase- and AmpC-Producing Escherichia coli and Klebsiella pneumoniae in Pediatric Patients

The objective of this study was to determine whether antibiotic exposure is associated with extended-spectrum-beta-lactamase- or AmpC-producing Escherichia coli or Klebsiella pneumoniae infections in children. We collected extended-spectrum-beta-lactamase- or AmpC-producing E. coli or K. pneumoniae isolates and same-species susceptible controls from normally sterile sites of patients aged ≤21 years, along with associated clinical data, at four free-standing pediatric centers. After controlling for potential confounders, the relative risk of having an extended-spectrum-beta-lactamase-producing isolate rather than a susceptible isolate was 2.2 times higher (95% confidence interval [CI], 1.49 to 3.35) among those with antibiotic exposure in the 30 days prior to infection than in those with no antibiotic exposure. The results were similar when analyses were limited to exposure to third-generation cephalosporins, other broad-spectrum beta-lactams, or trimethoprim-sulfamethoxazole. Conversely, the relative risk of having an AmpC-producing versus a susceptible isolate was not significantly elevated with any antibiotic exposure in the 30 days prior to infection (adjusted relative risk ratio, 1.12; 95% CI, 0.65 to 1.91). However, when examining subgroups of antibiotics, the relative risk of having an AmpC-producing isolate was higher for patients with exposure to third-generation cephalosporins (adjusted relative risk ratio, 4.48; 95% CI, 1.75 to 11.43). Dose-response relationships between antibiotic exposure and extended-spectrum-beta-lactamase-producing or AmpC-producing isolates were not demonstrated. These results reinforce the need to study and implement pediatric antimicrobial stewardship strategies, and they indicate that epidemiological studies of third-generation cephalosporin-resistant E. coli and K. pneumoniae isolates should include resistance mechanisms when possible.

Long-term resistance trends of uropathogens and association with antimicrobial prophylaxis

BACKGROUND

The aim of this study was to identify long-term resistance trends of uropathogens and determine the effect of prophylaxis in a pediatric patient population.

MATERIALS AND METHODS

A total of 638 uropathogens were isolated from urine samples collected from children hospitalized for urinary tract infection during the 12-year study period (1997-2008) and analyzed.

RESULTS

The most frequent uropathogen identified was Escherichia coli (69 %), followed by Klebsiella spp. (9.7 %), Pseudomonas aeruginosa (6.7 %), Enterococcus spp. (5.6 %), and Proteus spp. (4.4 %). High resistance rates were observed for common agents used for empiric treatment, such as amoxicillin, cotrimoxazole, and ceftriaxone. Resistance increased over time for nitrofurantoin, ceftriaxone, and piperacilin-tazobactam (chi-square for trend p < 0.0002, p < 0.0034 and p < 0.014, respectively) and decreased for cefuroxime (p < 0.016) and gentamicin (p < 0.014). The use of prophylaxis was related to an increased proportion of non-E. coli pathogens (46.9 vs. 26.9 %; odds ratio 2.4, 95 % confidence interval 1.61-3.55; p < 0.0001), as well as to increased resistance of non-E. coli pathogens, and was a major risk factor associated with resistance to amoxiclav (p < 0.005), cotrimoxazole (p < 0.0001), cefuroxime (p < 0.0001), ceftriaxone (p < 0.0001), gentamicin (p < 0.0001), and nitrofurantoin (p < 0.0001).

CONCLUSIONS

Our findings point to considerable changes in the long-term resistance patterns of uropathogens and an association of prophylaxis with resistance. Our results suggest the need for continuous surveillance, re-evaluation of empiric regimens and further assessment of the role of prophylaxis in the treatment of urinary tract infection.

Technical report—Diagnosis and management of an initial UTI in febrile infants and young children

OBJECTIVES

The diagnosis and management of urinary tract infections (UTIs) in young children are clinically challenging. This report was developed to inform the revised, evidence-based, clinical guideline regarding the diagnosis and management of initial UTIs in febrile infants and young children, 2 to 24 months of age, from the American Academy of Pediatrics Subcommittee on Urinary Tract Infection.

METHODS

The conceptual model presented in the 1999 technical report was updated after a comprehensive review of published literature. Studies with potentially new information or with evidence that reinforced the 1999 technical report were retained. Meta-analyses on the effectiveness of antimicrobial prophylaxis to prevent recurrent UTI were performed.

RESULTS

Review of recent literature revealed new evidence in the following areas. Certain clinical findings and new urinalysis methods can help clinicians identify febrile children at very low risk of UTI. Oral antimicrobial therapy is as effective as parenteral therapy in treating UTI. Data from published, randomized controlled trials do not support antimicrobial prophylaxis to prevent febrile UTI when vesicoureteral reflux is found through voiding cystourethrography. Ultrasonography of the urinary tract after the first UTI has poor sensitivity. Early antimicrobial treatment may decrease the risk of renal damage from UTI.

CONCLUSIONS

Recent literature agrees with most of the evidence presented in the 1999 technical report, but meta-analyses of data from recent, randomized controlled trials do not support antimicrobial prophylaxis to prevent febrile UTI. This finding argues against voiding cystourethrography after the first UTI.

Characterisation of uropathogenic Escherichia coli from children with urinary tract infection in different countries

Uropathogenic Escherichia coli (UPEC) carry many virulence factors, including those involved in long-term survival in the urinary tract. However, their prevalence and role among UPEC causing urinary tract infection (UTI) in children is not well studied. To further understand the virulence characteristics of these bacteria, we investigated the prevalence of antibiotic resistance, antigen 43 genes, curli and cellulose among UPEC in children from different countries. Isolates (n = 337) from five countries were tested for antibiotic susceptibility, phylogenetic groups, prevalence of flu, fluA(CFT073), fluB(CFT073), curli and cellulose. High prevalence of multidrug resistance and extended spectrum beta lactamase production was found among Iranian and Vietnamese isolates. Resistance was associated with phylogenetic group D while group B2 was associated with fluA(CFT073) and fluB(CFT073). Fewer Iranian isolates carried fluA(CFT073), curli and cellulose. fluB(CFT073) was most prevalent among Slovak isolates. Ampicillin and amoxicillin/clavulanic acid resistance was prevalent among fluA(CFT073)- and fluB(CFT073)-positive Australian, Iranian and Swedish isolates. Lack of curli and cellulose was associated with resistance among Vietnamese isolates. We conclude that major differences exist in the prevalence of antibiotic resistance among UPEC from different countries. Associations observed between resistance and virulence factors may, in different ways, promote the long-term survival of UPEC in the urinary tract.