Incidence of single-drug resistant, multidrug-resistant and extensively drug-resistant Escherichia coli urinary tract infections: An Australian laboratory-based retrospective study

Genomic characterization of extended-spectrum beta-lactamase-producing and carbapenem-resistant Escherichia coli from urban wastewater in Australia

This study investigates extended-spectrum beta-lactamase-producing and carbapenem-resistant Escherichia coli isolates from Sydney's wastewater. These isolates exhibit resistance to critical antibiotics and harbor novel resistance mechanisms. The findings highlight the importance of wastewater-based surveillance in monitoring resistance beyond the clinical setting.

Risk Factors and the Impact of Multidrug-Resistant Bacteria on Community-Acquired Urinary Sepsis

Risk factors for multidrug-resistant bacteria (MDRB) in nosocomial urinary tract infection (UTI) have been widely studied. However, these risk factors have not been analyzed in community-acquired urinary sepsis (US), nor have its outcomes been studied. The aim of our study is to determine risk factors for MDRB in community-acquired US and its influence on outcomes. Prospective observational study of patients with community-acquired US admitted to a university hospital. We compared epidemiological and clinical variables and outcomes of US due to MDRB and non-MDRB. Independent risk factors for MDRB were analyzed using logistic regression. A total of 193 patients were included, 33.7% of them with US due to MDRB. The median age of patients was 82 years. Hospital mortality was 17.6%, with no difference between the MDRB and non-MDRB groups. The length of hospital stay was 5 (4-8) days, with a non-significant tendency to longer hospital stays in the MDRB group (6 (4-10) vs. 5 (4-8) days, p = 0.051). Healthcare-associated US was found to be an independent risk factor for MDR bacteria by multivariate analysis. In conclusion, the impact of MDR bacteria on the outcomes of community-acquired urinary sepsis was mild. Healthcare-associated US was an independent risk factor for MDR bacteria.

Sex differences in aged 80 and over hospitalized patients with community-acquired UTI: A prospective observational study

Aim

This study aimed to evaluate clinically significant sex differences that could have an effect on the choice of treatment and outcomes of urinary tract infection (UTI) in aged 80 and over hospitalized patients with community-acquired UTI.

Methods

This was a prospective study of 161 patients aged 80 and over admitted to hospital with community-acquired UTI. Epidemiological, clinical, laboratory and microbiologic variables were compared between both sexes. Multivariate analysis was performed using logistic regression to determine the variables independently associated with sex.

Results

In a population of 91 (56.52%) women and 70 (43.48%) men, aged 80 and over, we found that women were more likely to have cognitive impairment (p = 0.035) and less likely to have chronic obstructive pulmonary disease (COPD) (p = 0.006) and indwelling urinary catheter (p < 0.001) than men. Levels of creatinine were higher in men than in women (p = 0.008). Septic shock at presentation was more frequent in the male group (p = 0.043). Men had a higher rate of polymicrobial infection (p = 0.035) and Pseudomonas aeruginosa infection (p = 0.003). Factors independently associated with sex by multivariate analysis were septic shock, cognitive impairment, COPD and indwelling urinary catheter.

Conclusion

Men aged 80 and over with community-acquired UTI had more septic shock at admission to hospital and higher rates of indwelling urinary catheter, while women had more cognitive impairment. There were no differences in outcomes between sexes.

Antimicrobial resistance in urinary pathogens and culture-independent detection of trimethoprim resistance in urine from patients with urinary tract infection

Background

Although urinary tract infections (UTIs) are extremely common, isolation of causative uropathogens is not always routinely performed, with antibiotics frequently prescribed empirically. This study determined the susceptibility of urinary isolates from two Health and Social Care Trusts (HSCTs) in Northern Ireland to a range of antibiotics commonly used in the treatment of UTIs. Furthermore, we determined if detection of trimethoprim resistance genes (dfrA) could be used as a potential biomarker for rapid detection of phenotypic trimethoprim resistance in urinary pathogens and from urine without culture.

Methods

Susceptibility of E. coli and Klebsiella spp. isolates (n = 124) to trimethoprim, amoxicillin, ceftazidime, ciprofloxacin, co-amoxiclav and nitrofurantoin in addition to susceptibility of Proteus mirabilis (n = 61) and Staphylococcus saprophyticus (n = 17) to trimethoprim was determined by ETEST® and interpreted according to EUCAST breakpoints. PCR was used to detect dfrA genes in bacterial isolates (n = 202) and urine samples(n = 94).

Results

Resistance to trimethoprim was observed in 37/124 (29.8%) E. coli and Klebsiella spp. isolates with an MIC₉₀ > 32 mg/L. DfrA genes were detected in 29/37 (78.4%) trimethoprim-resistant isolates. Detection of dfrA was highly sensitive (93.6%) and specific (91.4%) in predicting phenotypic trimethoprim resistance among E. coli and Klebsiella spp. isolates. The dfrA genes analysed were detected using a culture-independent PCR method in 16/94 (17%) urine samples. Phenotypic trimethoprim resistance was apparent in isolates cultured from 15/16 (94%) dfrA-positive urine samples. There was a significant association (P < 0.0001) between the presence of dfrA and trimethoprim resistance in urine samples containing Gram-negative bacteria (Sensitivity = 75%; Specificity = 96.9%; PPV = 93.8%; NPV = 86.1%).

Conclusions

This study demonstrates that molecular detection of dfrA genes is a good indicator of trimethoprim resistance without the need for culture and susceptibility testing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02551-9.

Clinical impact of multidrug-resistant bacteria in older hospitalized patients with community-acquired urinary tract infection

Introduction

Previous studies have described some risk factors for multidrug-resistant (MDR) bacteria in urinary tract infection (UTI). However, the clinical impact of MDR bacteria on older hospitalized patients with community-acquired UTI has not been broadly analyzed. We conducted a study in older adults with community-acquired UTI in order to identify risk factors for MDR bacteria and to know their clinical impact.

Methods

Cohort prospective observational study of patients of 65 years or older, consecutively admitted to a university hospital, diagnosed with community-acquired UTI. We compared epidemiological and clinical variables and outcomes, from UTI due to MDR and non-MDR bacteria. Independent risk factors for MDR bacteria were analyzed using logistic regression.

Results

348 patients were included, 41.4% of them with UTI due to MDR bacteria. Median age was 81 years. Hospital mortality was 8.6%, with no difference between the MDR and non-MDR bacteria groups. Median length of stay was 5 [4–8] days, with a longer stay in the MDR group (6 [4–8] vs. 5 [4–7] days, p = 0.029). Inadequate empirical antimicrobial therapy (IEAT) was 23.3%, with statistically significant differences between groups (33.3% vs. 16.2%, p < 0.001). Healthcare-associated UTI variables, in particular previous antimicrobial therapy and residence in a nursing home, were found to be independent risk factors for MDR bacteria.

Conclusions

The clinical impact of MDR bacteria was moderate. MDR bacteria cases had higher IEAT and longer hospital stay, although mortality was not higher. Previous antimicrobial therapy and residence in a nursing home were independent risk factors for MDR bacteria.

Susceptibility of Multidrug-Resistant and Biofilm-Forming Uropathogens to Mexican Oregano Essential Oil

Antibiotic resistance along with biofilm formation increases the difficulty for antibiotic therapy in urinary tract infections. Bioactive molecules derived from plants, such as those present in essential oils, can be used to treat bacterial infections. Oregano is one of the spices to have antimicrobial activity. Therefore, three Mexican oregano essential oils (two Lippia berlandieri Schauer and one Poliomintha longiflora) were tested for antimicrobial capacity against multidrug-resistant, biofilm-forming bacterial isolates. Clinical isolates from urinary tract infections were tested for antibiotic resistance. Multidrug-resistant isolates were evaluated for biofilm formation, and Mexican oregano antimicrobial effect was determined by the minimal inhibitory (CMI) and minimal bactericidal concentrations (CMB). The selected isolates were identified by molecular phylogenetic analysis. Sixty-one isolates were included in the study; twenty were characterized as multidrug-resistant and from those, six were strong biofilm formers. Three isolates were identified as Escherichia coli, two as Pseudomonas aeruginosa and one as Enterococcus faecalis based on the phylogenetic analysis of 16 S rRNA gene sequences. The antimicrobial effect was bactericidal; E. faecalis was the most susceptible (<200 mg/L CMI/CMB), and P. aeruginosa was the most resistant (>2,000 mg/L CMI/CMB). There was a range of 500-1000 mg/L (CMI/CMB) for the E. coli isolates. Mexican oregano essential oils demonstrated antimicrobial efficacy against multidrug-resistant clinical isolates.