Antimicrobial Resistance Trends of Escherichia coli Isolates from Outpatient and Inpatient Urinary Infections over a 20-Year Period

SWOT and Root Cause Analyses of Antimicrobial Resistance to Oral Antimicrobial Treatment of Cystitis

Nearly 150 million cases of urinary tract infections (UTIs) are reported each year, of which uncomplicated cystitis triggers > 25% of outpatient prescriptions of oral antimicrobial treatment (OAT). OAT aids immune cells infiltrating the urothelium in eliminating uropathogens capable of invading the urothelium and surviving hyperosmotic urine. This self-evident adaptability of uropathogens and the short interval between the introduction of Penicillin and the first report of antimicrobial resistance (AMR) implicate AMR as an evolutionary conserved heritable trait of mutant strains selected by the Darwinian principle to survive environmental threats through exponential proliferation. Therefore, AMR can only be countered by antimicrobial stewardship (AMS) following the principle of the five Ds-drug, dose, duration, drug route, and de-escalation. While convenient to administer, the onset of the minimum inhibitory concentration (MIC) for OAT in urine leaves a window of opportunity for uropathogens to survive the first contact with an antimicrobial and arm their descendant colonies with AMR for surviving subsequent higher urine antimicrobial levels. Meanwhile, the initial dose of intravesical antimicrobial treatment (IAT) may be well above the MIC. Therefore, the widespread clinical use of OAT for cystitis warrants an analysis of the strengths, weaknesses, opportunity, and threats (SWOTs) and a root cause analysis of the AMR associated with OAT and IAT.

Antimicrobial Resistance of Genital Mycoplasma and Ureaplasma: A Multicentre Study Over a 5-Year Period in Italy (2017-2021)

Updated data on genital Mollicutes prevalence and antimicrobial susceptibility can help provide guidance for antibiotic stewardship and set up effective strategies for infection control policies. In this multicentre study, we assessed the prevalence and the resistance profile of Mycoplasma hominis (MH) and Ureaplasma species (U. parvum/U. urealyticum), analyzing data from 21,210 subjects who provided urogenital samples for Mollicutes detection by culture over a 5-year period (2017-2021) in two high-density urban areas in the North of Italy (i.e., Bologna and Lecco). Overall prevalence of Mollicutes infection was 22.3%, with women showing a significantly higher detection rate than men (p < 0.00001). The prevalence decreased with age (highest prevalence <30 years) and over the years considered. Ureaplasma strains were much more frequently detected (62.3%) compared to MH (8.3%) and to mixed infections (29.4%). Ureaplasma species showed high levels of ciprofloxacin resistance (39.5%), whereas MH strains were nonsusceptible to azithromycin and roxithromycin in about 60% of cases. Over time, a significant decrease of resistance to azithromycin and doxycycline was detected (p < 0.0001 and 0.0004, respectively), in parallel with an important increase of ciprofloxacin-resistance levels (p < 0.0001). Overall, our results revealed that minocycline and josamycin can be first-line drugs for Mollicutes empirical treatment.

Carbapenem resistant Enterobacterales in the United Arab Emirates: a retrospective analysis from 2010 to 2021

Background

Carbapenem-resistant Enterobacterales (CRE) are spreading in the United Arab Emirates (UAE) where their dissemination is facilitated by international travel, trade, and tourism. The objective of this study is to describe the longitudinal changes of CRE as reported by the national AMR surveillance system of the UAE.

Methods

In this study, we retrospectively describe CRE isolated from 317 surveillance sites, including 87 hospitals and 230 centers/clinics from 2010 to 2021. The associated clinical, demographic, and microbiological characteristics are presented by relying on the UAE national AMR surveillance program. Data was analyzed using WHONET microbiology laboratory database software (http://www.whonet.org).

Results

A total of 14,593 carbapenem resistant Enterobacterales were analyzed, of which 48.1% were carbapenem resistant Klebsiella pneumoniae (CRKp), 25.1% carbapenem resistant Escherichia coli (CREc), and 26.8% represented 72 other carbapenem resistant species. Carbapenem resistant strains were mostly associated with adults and isolated from urine samples (36.9% of CRKp and 66.6% of CREc) followed by respiratory samples (26.95% for CRKp) and soft tissue samples (19.5% for CRKp). Over the studied period carbapenem resistance rates remained high, especially in K. pneumoniae, and in 2021 were equivalent to 67.6% for imipenem, 76.2% for meropenem, and 91.6% for ertapenem. Nevertheless, there was a statistically significant decreasing trend for imipenem and meropenem resistance in Klebsiella species (p < 0.01) while the decrease in ertapenem resistance was non-significant. Concerning E. coli, there was a statistically significant decreasing trend for meropenem and imipenem resistance over the 12 years, while ertapenem resistance increased significantly with 83.8% of E. coli exhibiting ertapenem resistance in 2021. Resistance rates to ceftazidime and cefotaxime remained higher than 90% (in 2021) for CRKp and cefotaxime rates increased to 90.5% in 2021 for CREc. Starting 2014, resistance to colistin and tigecycline was observed in carbapenem resistant Enterobacterales. CRE were associated with a higher mortality (RR: 6.3), admission to ICU (RR 3.9), and increased length of stay (LOS; 10 excess inpatient days per CRE case).

Conclusion

This study supports the need to monitor CRE in the UAE and draws attention to the significant increase of ertapenem resistance in E. coli. Future surveillance analysis should include a genetic description of carbapenem resistance to provide new strategies.

Occurrence of plasmid-mediated fosfomycin resistance (fos genes) among Escherichia coli isolates, Portugal

OBJECTIVES

To evaluate the occurrence of plasmid-mediated fos genes among fosfomycin-resistant Escherichia coli isolates collected from patients in Lisbon, Portugal, and characterize the fos-positive strains.

METHODS

A total of 19 186 E. coli isolates were prospectively collected between April 2022 and January 2023 from inpatients and outpatients at a private laboratory in Lisbon. Fosfomycin resistance was initially assessed by semi-automated systems and further confirmed by the disc diffusion method. Resistant isolates were investigated for plasmid-mediated fos genes (fosA1-fosA10, fosC and fosL1-fosL2) and extended-spectrum beta-lactamases (ESBLs) by PCR and sequencing. Multilocus sequence typing was performed to evaluate the clonal relationship among fos-carrying isolates.

RESULTS

Out of the 19 186 E. coli isolates, 100 were fosfomycin-resistant (0.5%), out of which 15 carried a fosA-like gene (15%). The most prevalent fosfomycin-resistant determinant was fosA3 (n = 11), followed by fosA4 (n = 4). Among the 15 FosA-producing isolates, 10 co-produced an ESBL (67%), being either of CTX-M-15 (n = 8) or CTX-M-14 (n = 2) types. The fosA3 gene was carried on IncFIIA-, IncFIB-, and IncY-type plasmids, whereas fosA4 was always located on IncFIB-type plasmids. Most FosA4-producing isolates belonged to a single sequence type ST2161, whereas isolates carrying the fosA3 gene were distributed into nine distinct genetic backgrounds.

CONCLUSION

The prevalence of fosfomycin-resistant E. coli isolates is still low in Portugal. Notably, 15% of fosfomycin-resistant isolates harbour a transferable fosA gene, among which there is a high rate of ESBL producers, turning traditional empirical therapeutical options used in Portugal (fosfomycin and amoxicillin-clavulanic acid) ineffective.

Treating urinary tract infections in the era of antibiotic resistance

INTRODUCTION

Urinary tract infections (UTIs) are associated with 25-40% of antibiotics consumed in primary care and are, therefore, driving antibiotic resistance. The worldwide increase in antibiotic resistance especially in Escherichia coli has complicated the treatment choices for UTIs and absence of effective oral antibiotics may lead to increasing need for more effective treatments.

AREAS COVERED

In this review we focus on the importance of the correct diagnosis of UTI as based on proof of urinary pathogens in the urine and discuss diagnostic measures including microscopy, dipstick, and culture. Antibiotic treatment can often await diagnostic measures with pain relief such as ibuprofen. The risk of an uncomplicated UTI leading to pyelonephritis is low (1-2%) and presence of bacteria in the bladder leaves some time for the immune system to react. Three antibiotics are recommended as based on their activity, and low propensity to select for resistance, i.e. nitrofurantoin, fosfomycin, and pivmecillinam, and in general, 3-5 days of treatment will suffice.

EXPERT OPINION

Understanding the usual benign course of uUTIs can help reduce antibiotic treatment in many cases, e.g. starting treatment by pain relief and awaiting the course of infection without antibiotics. Better rapid tests in primary care are urgently needed to enforce such policies.

Pivmecillinam, the paradigm of an antibiotic with low resistance rates in Escherichia coli urine isolates despite high consumption

OBJECTIVES

Pivmecillinam, the oral version of mecillinam, represents one of the major recommended and used antibiotics for empiric and targeted treatment of urinary tract infections in primary care in Denmark, Norway and Sweden. Mecillinam resistant mutants in Escherichia coli develop easily in vitro, but their fitness cost has been shown to be high.

METHODS

We revisited the resistance and consumption data from the monitoring programmes in the three countries and compared pivmecillinam with ciprofloxacin from 2010 to 2020.

RESULTS

Mecillinam resistance rates in Escherichia coli remained around 6% in Denmark and Norway relative to a constant consumption in Norway of 1.6-1.8 DID (defined daily doses per 1000 inhabitants per day), and even increasing in Denmark from 1.6 to 2.3 DID. In Sweden resistance was significantly lower at 4% related to the lower consumption of 0.5 DID. For ciprofloxacin, resistance rates fluctuated around 6%-12%, highest in Sweden with the highest consumption (0.8-0.6 DID) and lowest in Denmark (0.55-0.35 DID) and Norway (0.7-0.3 DID), although consumption declined significantly in all three countries.

CONCLUSIONS

Pivmecillinam is an example of an antibiotic, which easily develops resistance in vitro, but apparently can be used broadly in primary care without increase in resistance rates.

Exploration of the Structure-Function Relationships of a Novel Frog Skin Secretion-Derived Bioactive Peptide, t-DPH1, through Use of Rational Design, Cationicity Enhancement and In Vitro Studies

Amphibian skin-derived antimicrobial peptides (AMPs) have attracted increasing attention from scientists because of their excellent bioactivity and low drug resistance. In addition to being the alternative choice of antibiotics or anticancer agents, natural AMPs can also be modified as templates to optimise their bioactivities further. Here, a novel dermaseptin peptide, t-DPH1, with extensive antimicrobial activity and antiproliferative activity, was isolated from the skin secretion of Phyllomedusa hypochondrialis through 'shotgun' cloning. A series of cationicity-enhanced analogues of t-DPH1 were designed to further improve its bioactivities and explore the charge threshold of enhancing the bioactivity of t-DPH1. The present data suggest that improving the net charge can enhance the bioactivities to some extent. However, when the charge exceeds a specific limit, the bioactivities decrease or remain the same. When the net charge achieves the limit, improving the hydrophobicity makes no sense to enhance bioactivity. For t-DPH1, the upper limit of the net charge was +7. All the designed cationicity-enhanced analogues produced no drug resistance in the Gram-negative bacterium, Escherichia coli. These findings provide creative insights into the role of natural drug discovery in providing templates for structural modification for activity enhancement.

Multi-Drug Resistant Bacteria as Aetiological Factors of Infections in a Tertiary Multidisciplinary Hospital in Poland

Global and local initiatives were recently undertaken to reduce the burden of antibiotic resistance. The aim of the study was to describe the incidence and the aetiology of bacterial infections among hospitalized patients with special attention paid to the multidrug resistant (MDR) bacteria. This retrospective study was based on prospectively collected data from 150,529 consecutive patients hospitalized in a tertiary multidisciplinary hospital in the years 2017–2019. All consecutive microbiological tests from any biological material performed in the analyzed period were included. Microbiological screening tests (n = 10,677) were excluded. The analysis was focused on aetiological factors of bacterial infections, especially the incidence of MDR bacteria and mechanisms of antibiotic resistance. There were 58,789 microbiological tests performed in the analyzed period. The highest testing rate was noticed for intensive care unit (mean of 3.1 tests per one patient), followed by neonatal intensive care unit (2.7), internal medicine (1.9), pediatrics (1.8), and urology (1.2). Among 58,789 tests, 7690 (13.1%) were positive. MDR bacteria were responsible for 1783 infections (23.2%). The most common antibiotic resistance mechanism reported was ESBL production by Klebsiella spp. or Escherichia coli or Enterobacter spp. isolates (47.3% of all MDR cases). ESBL cases were followed by MRSA (14.7%), VRE (14.2%) and MBL producing Klebsiella spp. (5.6%). Among all infections caused by MDR bacteria, 1175 (65.9%) were diagnosed after 72 h of hospitalization (hospital-acquired infections). Apart from AmpC and ESBL producing Escherichia coli, all MDR bacteria were significantly more common in hospital-acquired infection. MDR bacteria are aetiological factors of a significant portion of infections in hospitalized patients with no remarkable change in the incidence in recent years. Production of ESBL is the most common mechanism of antibiotic resistance and should be regarded as one of the most urgent problems in clinical microbiology.