Fosfomycin for the treatment of drug-resistant urinary tract infections: potential of an old drug not explored fully

Antibiotic efficacy and resistance patterns of urinary tract infection-causing bacteria in dogs and resistome of multidrug-resistant Klebsiella pneumoniae via whole genome sequencing in South Korea

Bacterial urinary tract infections (UTIs) are prevalent in dogs and necessitate antibiotic intervention. However, the emergence of multidrug-resistant (MDR) bacteria poses significant challenges to antibiotic therapy. Although fosfomycin has been demonstrated to achieve and maintain high concentrations in urine, suggesting its potential for treating UTIs in dogs, its efficacy and the resistance profiles of urinary pathogens from canine UTIs remain elusive. Therefore, this study was conducted to investigate the antibiotic susceptibility of bacterial pathogens isolated from companion dogs with UTIs, with a particular focus on their susceptibility and resistance to fosfomycin. A total of 70 isolates from urine samples were analyzed, of which Escherichia coli (n = 18), Proteus mirabilis (n = 9), Klebsiella pneumoniae (n = 5), and Staphylococcus pseudintermedius (n = 5) were predominant. Resistance to erythromycin was most prevalent (94.59%), followed by clindamycin (91.89%) and ampicillin (78.37%), whereas the lowest resistance rate was observed for amikacin (5.40%). Resistance to fosfomycin was observed in 15 out of the 37 predominant isolates (40.54%), including all K. pneumoniae isolates (100%). All isolates, except 4 E. coli strains, were categorized as MDR (33 out of 37; 89.18%). The resistance rates for amoxicillin/clavulanic acid and trimethoprim-sulfamethoxazole, which are common first-line antibiotics for canine UTIs, were 48.64 and 56.75%, respectively. Whole-genome sequencing of K. pneumoniae isolates, which exhibited high resistance to fosfomycin, revealed multiple antibiotic resistance genes, with chromosomal fosA present in all isolates. Among the 27 dogs with recurrent infection included in this study, 2 were administered fosfomycin, resulting in clinical remission, as evidenced by negative urine culture tests. Overall, this study is the first to demonstrate the importance of assessing fosfomycin resistance profile for optimal treatment of canine UTIs, particularly in cases involving MDR strains.

Pre- and Post-COVID-19 Appraisal of Antimicrobial Susceptibility for Urinary Tract Infections at an Outpatient Setting of a Tertiary Care Hospital in Delhi

BACKGROUND

This study was conducted to understand the effect of the COVID-19 pandemic on urine culture and sensitivity results in an outpatient setting. There are plenty of data from inpatient and ICU settings but there is a paucity of data in outpatient or community settings. Thus, this study primarily targeted change in antibiotic resistance of urinary tract infection (UTI) agents in the pre- and post-COVID-19 period.

METHODS

In the study, urine samples received in the Department of Laboratory Medicine (microbiology laboratory) with a preliminary diagnosis of UTI between April 2019 and March 2021 were analyzed. Urine cultures and antibiotic susceptibility tests of the patients included in the study were examined in two periods (pre-pandemic and post-pandemic).

RESULTS

A total of 22,372 urine samples were received in the pre-pandemic period (April 2019 to March 2020) and 4885 samples in the post-pandemic period (April 2020 to March 2021). The positivity rate obtained from urine cultures sent post-COVID-19 pandemic (16%) was significantly higher than those sent before the COVID-19 pandemic (8%). According to cultures and antibiogram results, resistance to ampicillin, amikacin, ceftazidime (p < 0.05), co-trimoxazole, levofloxacin, gentamicin (p < 0.05), nitrofurantoin, fosfomycin, and tetracycline decreased compared with the pre-COVID-19 period.

CONCLUSIONS

In this study, we found that the frequency of significant bacteriuria increased significantly in the post-pandemic period. However, resistance to antibiotics decreased significantly in the post-COVID-19 period compared to the pre-COVID-19 period. There was no significant change in the etiology of UTI during the two time periods.

Limited Therapeutic Options in Mexico for the Treatment of Urinary Tract Infections

The rise in antimicrobial resistance (AMR) has complicated the management of urinary tract infections (UTIs). The objective of this study was to evaluate the antimicrobial susceptibility patterns of Escherichia coli and Klebsiella pneumoniae. Design: prospective observational study. Bacteria were classified as susceptible or resistant to ampicillin-sulbactam, amikacin, gentamicin, ciprofloxacin, norfloxacin, nitrofurantoin, trimethoprim-sulfamethoxazole (TMP/SMZ), ertapenem, meropenem, and fosfomycin. The sensitivity to fosfomycin and chloramphenicol was evaluated by the disk diffusion method. Statistical analysis: the chi-square test and Fisher’s exact test were used to compare differences between categories. A p value < 0.05 was considered statistically significant. Isolates were collected from January 2019 to November 2020 from 21 hospitals and laboratories. A total of 238 isolates were received: a total of 156 E. coli isolates and 82 K. pneumoniae isolates. The majority were community-acquired infections (64.1%). Resistance was >20% for beta-lactams, aminoglycosides, fluoroquinolones, and TMP/SMZ. For E. coli isolates, resistance was <20% for amikacin, fosfomycin, and nitrofurantoin; for K. pneumoniae, amikacin, fosfomycin, chloramphenicol, and norfloxacin. All were susceptible to carbapenems. K. pneumoniae isolates registered a higher proportion of extensively drug-resistant bacteria in comparison with E. coli (p = 0.0004). In total, multidrug-resistant bacteria represented 61% of all isolates. Isolates demonstrated high resistance to beta-lactams, fluoro-quinolones, and TMP/SMZ.

Fosfomycin versus Nitrofurantoin for the Treatment of Lower UTI in Outpatients

Introduction Fosfomycin and nitrofurantoin are increasingly being prescribed in outpatients for the oral treatment of urinary tract infection (UTI). Although ample literature is available on the in vitro sensitivity pattern of fosfomycin and nitrofurantoin in UTI cases, clinical data are scant.

Methodology  Voided midstream urine, collected from patients ≥ 16 years of age of both genders with suspected sign and symptoms, was plated on cystine lactose electrolyte-deficient agar. Uropathogen was defined as an organism known to be associated with the signs and symptoms of UTI with > 10 ⁵ colony forming units/mL of urine. Antimicrobial susceptibility testing was determined by Kirby-Bauer disc diffusion method. Further, for fosfomycin, agar dilution method was also performed.

Results  A total of 143 patients, 47 treated with fosfomycin and 96 with nitrofurantoin, were followed for clinical outcome. The most common isolated uropathogen was Escherichiacoli . In vitro susceptibility rate of uropathogens against fosfomycin and nitrofurantoin was 99.3% and 81.2%, respectively. Overall, the clinical cure rate with fosfomycin and nitrofurantoin treatment groups was 80.85% and 90.06% respectively (not statistically significant).

Conclusion  Fosfomycin and nitrofurantoin showed good in vitro activity against uropathogens from lower UTI and can be used for empirical therapy in our area. Multiple confounding factors may have contributed to the discrepancy between in vitro susceptibility and clinical cure, which needs to be studied further.

Susceptibility pattern of oral antimicrobials in uncomplicated UTI: Does fosfomycin still stand effective?

INTRODUCTION

Urinary tract infections (UTIs) are a leading cause of morbidity amongst all age groups and most patients with uncomplicated UTI who visit the OPD are treated with empirical antibiotics without doing any culture analysis. Of all the oral antibiotics used in UTI, fosfomycin is well excreted in the urine and is being used for the treatment of UTIs with a single oral dose.

METHODOLOGY

The current study was planned to determine the resistance amongst uropathogens to various oral antibiotics including fosfomycin isolated over a 4-year period (April 2015 to March 2019).

RESULTS

A total of 22,546 urine samples were received from OPD patients over 4 years and of these, 7,295 isolates were obtained from patients with uncomplicated UTI. About 82% of the isolates were gram-negative bacilli (GNBs). The most common isolate was E. coli 1023 (67.2%) followed by Klebsiella spp 254 (16.7%), and Pseudomonas spp 63 (4.1%). Of all the antibiotics tested, maximum sensitivity in the year 2018 was found to fosfomycin followed by nitrofurantoin for all the isolates tested. There was a statistically significant increase in the resistance pattern for almost all antibiotics tested in gram-negative bacteria (both Enterobacteriaceae and nil fermenters) whereas the increase in the resistance was not statistically significant in gram-positive cocci.

CONCLUSION

It can be easily seen that the level of antibiotic resistance has been increasing even in the community with the rampant injudicious use of antibiotics in humans as well as livestock. As the level of resistance to fosfomycin is still low in the community, it can play a promising role in the treatment of infection in patients with uncomplicated UTI.

Evaluation of in vitro susceptibility of fosfomycin among Enterobacteriaceae isolates from urine cultures: A study from Puducherry

INTRODUCTION:

The increasing drug resistance among Gram-negative uropathogens and a lack of effective oral antibiotics have limited the therapeutic options available for urinary tract infections (UTIs). This shortage of newer antibiotics has paved the way for considering the use of older antibiotics such as fosfomycin. This study aims to evaluate the in vitro susceptibility of Enterobacteriaceae isolates to fosfomycin.

MATERIALS AND METHODS:

In this descriptive study conducted over a period of 6 months, we processed 1500 urine samples. The Enterobacteriaceae isolates were subjected to in vitro susceptibility testing to fosfomycin, in addition to the regularly used urinary antibiotics, by Kirby–Bauer disc-diffusion method.

RESULTS:

Of 1500 urine samples processed, 582 samples yielded the growth of pathogens. Enterobacteriaceae accounted for 392 (67.3%) of the isolates. Among these isolates, lower rates of resistance were observed for imipenem (4.1%) and fosfomycin (13.3%). Relatively higher rates of resistance were observed for nitrofurantoin (35.5%) and amikacin (30.9%). Nalidixic acid, norfloxacin, gentamicin, cefotaxime, and cotrimoxazole showed a high resistance rate of 82.7%, 69.6%, 52.3%, 69.1%, and 71.4%, respectively. All antibiotics, except fosfomycin, were in routine clinical use in our hospital. The low resistance (13.3%) to fosfomycin is indicative of its utility as an excellent urinary antibiotic.

CONCLUSIONS:

Uropathogenic Enterobacteriaceae isolates displayed excellent in vitro susceptibility to fosfomycin. These in vitro findings suggest the unexplored potential of fosfomycin as a superior therapeutic option for treating uncomplicated UTI.

Emergence of antibiotic resistance Pseudomonas aeruginosa in intensive care unit; a critical review

The emergence of antibiotic resistant bacteria in the healthcare is a serious concern. In the Healthcare premises precisely intensive care unit are major sources of microbial diversity. Recent findings have demonstrated not only microbial diversity but also drug resistant microbes largely habitat in ICU. Pseudomonas aeruginosa found as a part of normal intestinal flora and a significant pathogen responsible for wide range of ICU acquired infection in critically ill patients. Nosocomial infection associated with this organism including gastrointestinal infection, urinary tract infections and blood stream infection. Infection caused by this organism are difficult to treat because of the presence of its innate resistance to many antibiotics (β-lactam and penem group of antibiotics), and its ability to acquire further resistance mechanism to multiple class of antibiotics, including Beta-lactams, aminoglycosides and fluoroquinolones. In the molecular evolution microbes adopted several mechanism to maintain genomic plasticity. The tool microbe use for its survival is mainly biofilm formation, quorum sensing, and horizontal gene transfer and enzyme promiscuity. Such genomic plasticity provide an ideal habitat to grow and survive in hearse environment mainly antibiotics pressure. This review focus on infection caused by Pseudomonas aeruginosa, its mechanisms of resistance and available treatment options. The present study provides a systemic review on major source of Pseudomonas aeruginosa in ICU. Further, study also emphasizes virulence gene/s associated with Pseudomonas aeruginosa genome for extended drug resistance. Study gives detailed overview of antibiotic drug resistance mechanism.

New Insights in Treatment Options in Pediatric Urinary Tract Infection

Urinary tract infection (UTI) represents one of the most frequent infections with bacterial etiology during childhood. In infants and toddlers with fever without source UTI’ investigation should be carried out, since signs and symptoms are nonspecific. However, obtaining uncontaminated urine samples from these patients can be challenging and time consuming; all current collection methods (clean-catch, plastic collection bag, catheterization, etc) have disadvantages. Criteria for UTI definition are represented by the presence of significant number of a single uropathogen, this number being different depending on the collection method: at least 1000 colony-forming unit (CFU/ml) for catheter samples and at least 100.000 CFU/ml from midstream clean-catch samples or 50.000 CFU/ml and significant pyuria in a symptomatic or febrile child. Accurate diagnosis of UTI is essential to avoid any antibiotic overuse and expensive investigations. UTI caused by resistant bacterial strains has an increasing prevalence in children. In pediatric population, extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBLPE) represent the etiology of around 15% of UTIs. Because of limited therapeutic options the reintroduction of some old antimicrobial agents is necessary, therefore Nitrofurantoin and Fosfomycin, can represent alternatives for oral treatment and prophylaxis of UTIs in children or in case of resistance suspicion to other drug classes. It is important to recognize patients at risk, such as children with recurrent UTIs, kidney abnormalities, like vesicoureteral reflux and previous antibiotherapy, in order to recommend adequate empiric treatment, especially against resistant bacteria.

Development and validation of a LC-MS/MS method for quantitation of fosfomycin - Application to in vitro antimicrobial resistance study using hollow-fiber infection model

Extensive use and misuse of antibiotics over the past 50 years has contributed to the emergence and spread of antibiotic-resistant bacterial strains, rendering them as a global health concern. To address this issue, a dynamic in vitro hollow-fiber system, which mimics the in vivo environment more closely than the static model, was used to study the emergence of bacterial resistance of Escherichia coli against fosfomycin (FOS). To aid in this endeavor we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for quantitative analysis of FOS in lysogeny broth. FOS was resolved on a Kinetex HILIC (2.1 × 50 mm, 2.6 μm) column with 2 mm ammonium acetate (pH 4.76) and acetonitrile as mobile phase within 3 min. Multiple reaction monitoring was used to acquire data on a triple quadrupole mass spectrometer. The assay was linear from 1 to 1000 μg/mL. Inter- and intra-assay precision and accuracy were <15% and between ±85 and 115% respectively. No significant matrix effect was observed when corrected with the internal standard. FOS was stable for up to 24 h at room temperature, up to three freeze-thaw cycles and up to 24 h when stored at 4°C in the autosampler. In vitro experimental data were similar to the simulated plasma pharmacokinetic data, further confirming the appropriateness of the experimental design to quantitate antibiotics and study occurrence of antimicrobial resistance in real time. The validated LC-MS/MS assays for quantitative determination of FOS in lysogeny broth will help antimicrobial drug resistance studies.

Assessing the Importance of Domestic Vaccine Manufacturing Centers: An Overview of Immunization Programs, Vaccine Manufacture, and Distribution

Vaccines have significantly reduced the detrimental effects of numerous human infectious diseases worldwide, helped to reduce drastically child mortality rates and even achieved eradication of major pathogens, such as smallpox. These achievements have been possible due to a dedicated effort for vaccine research and development, as well as an effective transfer of these vaccines to public health care systems globally. Either public or private institutions have committed to developing and manufacturing vaccines for local or international population supply. However, current vaccine manufacturers worldwide might not be able to guarantee sufficient vaccine supplies for all nations when epidemics or pandemics events could take place. Currently, different countries produce their own vaccine supplies under Good Manufacturing Practices, which include the USA, Canada, China, India, some nations in Europe and South America, such as Germany, the Netherlands, Italy, France, Argentina, and Brazil, respectively. Here, we discuss some of the vaccine programs and manufacturing capacities, comparing the current models of vaccine management between industrialized and developing countries. Because local vaccine production undoubtedly provides significant benefits for the respective population, the manufacture capacity of these prophylactic products should be included in every country as a matter of national safety.