Carbapenem and Cephalosporin Resistance among Enterobacteriaceae in Healthcare-Associated Infections, California, USA1

Evaluation of Doctors' Knowledge, Attitudes, Behaviors, Awareness and Practices on Rational Antimicrobial Stewardship in a Training and Research Hospital in Mogadishu-Somalia

Introduction

Historically, antimicrobials have been used to treat microbial illnesses in humans and animals. But throughout this time, antibiotics that had been successful against particular microorganisms started to lose their effectiveness due to rising inappropriate use brought on by ignorance, negligent attitudes, and improper methods. Our goal in conducting this study was to ascertain the knowledge, attitudes, and practices of doctors with relation to the use of antibiotics in light of the growing global and Sub-Saharan African problem of antimicrobial resistance.

Methods

In a tertiary hospital in Mogadishu, Somalia, a cross-sectional survey study was carried out to assess experts' and research assistants' knowledge, attitudes, behavior, awareness, and practices regarding the use of antibiotics and antibiotic resistance. A questionnaire consisting of 2 sections and 22 questions was applied to the participants on a voluntary basis.

Results

Among the 202 doctors that participated in the study, 49 (24.3%) were specialists, and 153 (75.7%) were assistants. Prescriptions for one to ten antibiotic boxes per week on average were reported by 146 respondents (72.3%). Of the physicians, just 27 (13.4%) did not require assistance when prescribing an antibiotic. The most often accessed sources of support were experts in infectious diseases (43.1%) and national/international antimicrobial guidelines (32.2%). The top three factors contributing to antibiotic resistance in Somalia include misuse of antibiotics (61.4%), unnecessary prescriptions written by doctors (44.6%), and an absence of infectious disease specialists in most institutions (44.1%).

Conclusion

As an alarming level of antimicrobial resistance has been observed globally in recent years, the results of our survey will help educate our doctors by gauging their perceptions, attitudes, and knowledge about rational antibiotic use in Sub-Saharan Africa. This will provide better patient outcomes.

The prevalence of multidrug resistance in uropathogens of patients admitted in the intensive care unit of a tertiary care hospital

Urinary tract infections (UTIs) are among the most common bacterial infections, posing significant public health challenges due to increasing antimicrobial resistance (AMR). This study aims to assess the prevalence, demographic characteristics, microbial profile, and antimicrobial resistance patterns in Indian patients with UTIs admitted to intensive care unit. A total of 154 patients with positive UTIs were included in this cross-sectional study. The prevalence data including demographics, microbial isolates, and antimicrobial susceptibility patterns were collected. Additionally, risk factors for multidrug resistance uropathogens were assessed using multivariate analyses. The patient cohort had diverse demographic, with a slight male predominance of 52.6% (n = 81). The most common comorbidities were hypertension 59.1% (n = 91) and diabetes mellitus 54.5% (n = 84). The microbial profile was dominated by gram-negative bacteria, particularly Escherichia coli 26.62% (n = 41) and Klebsiella pneumoniae 17.53% (n = 27). The predominant gram-positive and fungal isolate was Enterococcus faecium 7.14% (n = 11) and Candida spp. 18.83% (n = 29), respectively. Substantial resistance was noted against common antimicrobials, with variations across different pathogens. Gram-negative bacteria, particularly Escherichia coli and Klebsiella pneumoniae, exhibited high MDR rates, emphasizing the challenge of antimicrobial resistance. Multivariate logistic regression identified age groups 50-65 and over 65, and prolonged catheterization as significant risk factors for MDR infections. A significantly high resistance rate among pathogens emphasizes the need for judicious antimicrobial use. Our findings emphasize the necessity of ongoing surveillance and tailored interventions based on local pathogen prevalence and antibiogram data to effectively address the threat of AMR threat for better management of UTI management in ICU settings.

The Prevalence of Alert Pathogens and Microbial Resistance Mechanisms: A Three-Year Retrospective Study in a General Hospital in Poland

The development of antibiotic resistance mechanisms hinders the treatment process. So far, there is limited data on the problem of bacterial resistance in hospitals in Central and Eastern Europe. Therefore, this study aimed to assess the prevalence of resistance mechanisms and alert pathogens based on reports regarding cultures of samples collected from general hospital patients in Poland in the period 2019-2021. This study examined the prevalence of resistance mechanisms and alert pathogens and the structure of microorganisms, including the type of diagnostic material in the hospital department. The frequency of occurrence and the trends were analysed based on Cochran's Q-test, relative change and the average annual rate of change (AARC). Of all 14,471 cultures, 3875 were positive for bacteria, and 737 were characterised by resistance mechanisms (19.0%). Alert pathogens were identified in 983 cases (24.6%), including pathogens isolated from blood samples. The most commonlyisolated bacteria were Escherichia coli (>20% of positive cultures), Enterococcus faecalis (7%), and Klebsiella pneumoniae (6%) increasing over time; Staphylococcus aureus (13%) was also found, but its proportion was decreasing over time. Extended-spectrum β-lactamase (ESBL) was the most frequent resistance mechanism in Internal Medicine (IM) (p < 0.001) and the Intensive Care Unit (ICU) (p < 0.01), as well as in ICU-COVID; this increased over the study period (AARC ↑34.9%). Methicillin-resistant Staphylococcus aureus (MRSA) (AARC ↓50.82%) and AmpC beta-lactamase (AARC ↓24.77%) prevalence fell over time. Also, the number of alert pathogens was dominant in the IM (p < 0.01) and ICU (p < 0.001). The most common alert pathogen was ESBL-positive E. coli. Gram-negative rods constitute a significant epidemiological problem in hospitals, especially the growing trend of ESBL in IM and ICU, which calls for increased control of sanitary procedures.

Metabolic reprogramming of the glutathione biosynthesis modulates the resistance of Salmonella Derby to ceftriaxone

Salmonella, a foodborne pathogen, has become a major public health concern because of its widespread drug resistance, including resistance to multiple drugs such as third-generation cephalosporin, ceftriaxone (CRO). However, the metabolic profile changes and associated mechanisms engendered by cephalosporin-resistant mutations remain uncharted. In this study, we have employed the LC-MS/MS metabolomics platform to determine the metabolic profiles of 138 strains of Salmonella. Our results show that metabolic profiles correspond to specific serotypes, sources, processing stages, and antibiotic resistance patterns. Notably, we observed that Salmonella Derby (S. Derby) with drug resistance to CRO has a different metabolic status with changes in glutathione biosynthesis. Specifically, glutathione oxidized (GSSG) and citrulline abundances are greatly suppressed in CRO-resistant S. Derby. Furthermore, exogenous GSSG or citrulline, but not glutathione reduced (GSH), restored the susceptibility of multidrug-resistant S. Derby to CRO. This study establishes a strategy based on functional metabolomics to manage the survival of antibiotic-resistant bacteria.

An In Vitro Susceptibility Study of Cefotaxime-Sulbactam on Clinical Bacterial Isolates From Various Regions in India: A Comparison With Ceftriaxone-Sulbactam

Background and objective Combining sulbactam with cefotaxime/ceftriaxone augments its antimicrobial activity against β-lactamase-producing bacteria. They are widely used as empirical treatment for many clinical infections. However, there is a scarcity of data on the susceptibility of various organisms to these antibiotics in the Indian region. In light of this, the present in vitro study evaluated the susceptibility of bacterial isolates to cefotaxime-sulbactam and compared it with ceftriaxone-sulbactam. Methodology Clinical samples with positive bacterial cultures from various laboratories in India were subjected to antibiotic sensitivity testing using in vitro E-test strips and disk diffusion methods to determine the minimum inhibitory concentration (MIC) and zone of inhibition (ZOI), respectively. MIC₅₀ and MIC₉₀ values were determined along with the measurement of the ZOI for the effectiveness of antibiotics. Interpretations of MIC and ZOI values were made as per the criteria set by the Clinical and Laboratory Standards Institute (CLSI) guidelines to estimate the proportion of sensitive organisms. Results Among 400 clinical isolates evaluated, Escherichia coli (E. coli) (47.75%) was the most common organism isolated followed by Klebsiella (26%), Salmonella (7.75%), Proteus (3.8%), and Acinetobacter (2.8%). The mean ZOI was found significantly higher for E. coli, Klebsiella, and Salmonella in the cefotaxime-sulbactam group than in the ceftriaxone-sulbactam group. MIC₅₀ values for E. coli and Klebsiella were 0.25 and 0.19 µg/ml, respectively in the cefotaxime-sulbactam group as compared to 0.38 and 0.25 µg/ml, respectively for ceftriaxone-sulbactam. The proportion of sensitive isolates was also higher in the cefotaxime-sulbactam group for E. coli, Klebsiella, and Salmonella. Conclusions The in vitro effect of cefotaxime-sulbactam on organisms is similar to that of ceftriaxone-sulbactam in terms of MIC, ZOI, and proportion of sensitivity based on our study involving clinical isolates from various parts of India. Cefotaxime-sulbactam may be preferred in the empirical management of various clinical infections.

Comparative In Vitro Activity of Ceftolozane/Tazobactam against Clinical Isolates of Pseudomonas aeruginosa and Enterobacterales from Five Latin American Countries

Background: Ceftolozane/tazobactam (C/T) is a combination of an antipseudomonal oxyiminoaminothiazolyl cephalosporin with potent in vitro activity against Pseudomonas aeruginosa and tazobactam, a known β-lactamase inhibitor. The aim of this study was to evaluate the activity of C/T against clinical isolates of P. aeruginosa and Enterobacterales collected from five Latin American countries between 2016 and 2017, before its clinical use in Latin America, and to compare it with the activity of other available broad-spectrum antimicrobial agents. Methods: a total of 2760 clinical isolates (508 P. aeruginosa and 2252 Enterobacterales) were consecutively collected from 20 hospitals and susceptibility to C/T and comparator agents was tested and interpreted following the current guidelines. Results: according to the CLSI breakpoints, 68.1% (346/508) of P. aeruginosa and 83.9% (1889/2252) of Enterobacterales isolates were susceptible to C/T. Overall, C/T demonstrated higher in vitro activity than currently available cephalosporins, piperacillin/tazobactam and carbapenems when tested against P. aeruginosa, and its performance in vitro was comparable to fosfomycin. When tested against Enterobacterales, it showed higher activity than cephalosporins and piperacillin/tazobactam, and similar activity to ertapenem. Conclusions: these results show that C/T is an active β-lactam agent against clinical isolates of P. aeruginosa and Enterobacterales.

Migratory birds as a potential overseas transmitter of Shiga toxin-producing Escherichia coli

Shiga toxin-producing Escherichia coli (STEC) has a great public health importance. This study was conducted to investigate the potential role of migratory birds in the transmission of STEC. For this purpose, cloacal swabs were collected from 349 migratory birds (209 ducks and 140 quails) from Damietta governorate, Egypt. The collected swabs were cultured for isolation of STEC using the STEC CHROMagar. STEC isolates were identified based on colonial characteristics, Gram's stain, conventional biochemical tests and molecular detection of stx1, stx2 and eae genes. Positive isolates were serotyped and examined for their antibiotic susceptibility pattern. Furthermore, gene sequencing was performed for genes stx1and stx2. Of the examined birds, two STEC isolates were a obtained with an overall occurrence rate 0.57% (2/349), one isolate carried stx2 gene from a migratory quail 0.71% (1/140), and another isolate from a migratory duck carried stx1 gene 0.48% (1/209), whereas both isolates were negative for eae gene. Moreover, the duck isolate was serotyped O86, while the quail isolate was serotyped O125; both isolates were multidrug resistant. The phylogenetic analysis of the obtained stx1 and stx2 genes revealed high genetic relatedness to those isolated from human cases in the countries where such birds either lived or were in their migratory pathway. In conclusion, this study highlights the potential role of migratory birds in transmitting multidrug-resistant STEC across their migratory pathway.

Environmental antimicrobial resistance and its drivers: a potential threat to public health

Imprudent and overuse of clinically relevant antibiotics in agriculture, veterinary and medical sectors contribute to the global epidemic increase in antimicrobial resistance (AMR). There is a growing concern among researchers and stakeholders that the environment acts as an AMR reservoir and plays a key role in the dissemination of antimicrobial resistance genes (ARGs). Various drivers are contributing factors to the spread of antibiotic-resistant bacteria and their ARGs either directly through antimicrobial drug use in health care, agriculture/livestock and the environment or antibiotic residues released from various domestic settings. Resistant micro-organisms and their resistance genes enter the soil, air, water and sediments through various routes or hotspots such as hospital wastewater, agricultural waste or wastewater treatment plants. Global mitigation strategies primarily involve the identification of high-risk environments that are responsible for the evolution and spread of resistance. Subsequently, AMR transmission is affected by the standards of infection control, sanitation, access to clean water, access to assured quality antimicrobials and diagnostics, travel and migration. This review provides a brief description of AMR as a global concern and the possible contribution of different environmental drivers to the transmission of antibiotic-resistant bacteria or ARGs through various mechanisms. We also aim to highlight the key knowledge gaps that hinder environmental regulators and mitigation strategies in delivering environmental protection against AMR.

A public health concern: emergence of carbapenem-resistant Klebsiella pneumoniae in a public transportation environment

OBJECTIVES

This study was designed to understand the prevalence of antibiotic-resistant bacteria in the Beijing subway environment and the potential transmission of carbapenem-resistant Enterobacteriaceae in a public transportation environment.

METHODS

Carbapenem-resistant isolates were selected on brain heart infusion agar supplemented with meropenem (0.5 mg/L) and antimicrobial susceptibility testing was conducted using the broth microdilution method. WGS analyses were conducted for 11 Klebsiella pneumoniae isolates to identify resistance genes. The genetic relationships among the isolates were evaluated by MLST and PFGE.

RESULTS

We identified 11 carbapenem-resistant K. pneumoniae isolates from the Beijing subway environment. WGS revealed three STs among the 11 isolates, with 9 isolates classified as ST726 and containing a blaNDM-5-carrying IncX3 plasmid. The genetic environment of blaNDM-5 was very similar to that observed in other blaNDM-5-containing clinical isolates.

CONCLUSIONS

The presence of carbapenem-resistant Enterobacteriaceae in a public transportation environment is concerning and indicates that regular antimicrobial resistance surveillance is urgent and necessary.

Mortality associated with third generation cephalosporin-resistance in Enterobacteriaceae infections: a multicenter cohort study in Southern China

Background: Emerging third-generation cephalosporin-resistant Enterobacteriaceae (3GCR-EB) pose global healthcare concern. This study assessed the in-hospital mortality attributed to 3GCR-EB.Methods: The study cohort comprised inpatients with community-onset or healthcare-associated infection caused by Enterobacteriaceae in three tertiary-care public hospitals in 2017. In-hospital mortality was compared between 3GCR-EB infected patients and third-generation cephalosporin-susceptible Enterobacteriaceae (3GCS-EB) infected patients using competing risk survival models.Results: Of 2,343 study patients (median age 60 years; 45.2% male), 1,481 (63.2%) had 3GCS-EB and 862 (36.8%) 3GCR-EB infection. 494 (57.0%) 3GCR-EB isolates were co-resistant to fluoroquinolones and 15 (1.7%) to carbapenems. In-hospital mortality was similar in 3GCS-EB and 3GCR-EB infections (2.4% vs. 2.8%; p = 0.601). No increase in the hazard of in-hospital mortality was detected for 3GCR-EB compared to 3GCS-EB infection (sub-distribution hazard ratio [HR] 0.80; 95%CI, 0.41-1.55) adjusting for patient age, sex, intensive care admission, origin of infection and site of infection. Analysis of cause-specific hazards showed that 3GCR-EB infections significantly decreased the daily rate of hospital discharge (cause-specific HR = 0.84; 95%CI, 0.76-0.92) leading to lengthier hospitalizations.Conclusion: 3GCR-EB infection per se was not associated with increased in-hospital mortality in this study, but placed significant healthcare burden by increasing the length of hospitalization.

Synergistic Activity of Equol and Meropenem against Carbapenem-Resistant Escherichia coli

The emergence of carbapenem-resistant Enterobacterales (CRE) seriously limits treatment options for bacterial infections. Combined drugs are an effective strategy to treat these resistant strains. This study aimed to evaluate the synergistic effect of equol and meropenem against carbapenem-resistant Escherichia coli. First, this study investigated the antibacterial activity of carbapenems on clinically isolated E. coli strains by analyzing the minimum inhibitory concentrations (MICs). The E. coli strains were all resistant to carbapenem antibiotics. Therefore, we confirmed the cause of carbapenem resistance by detecting bla_KPC and bla_OXA-48 among the carbapenemase genes using polymerase chain reaction (PCR) analysis. Checkerboard and time-kill analyses confirmed that equol restored the susceptibility of carbapenem-resistant E. coli to meropenem. Also, the transcription levels of specific carbapenemase genes in E. coli were significantly suppressed by equol. The study also evaluated the anti-virulence effects of equol on bacterial biofilm and motility through phenotypic and genotypic analyses. In conclusion, our results revealed that equol had a synergistic effect with meropenem on carbapenem-resistant E. coli. Therefore, this study suggests that equol is a promising antibiotic adjuvant that prevents the expression of carbapenemases and virulence factors in carbapenem-resistant E. coli.

Needs assessment for novel Gram-negative antibiotics in US hospitals: a retrospective cohort study

BACKGROUND

Evidence-based needs assessments for novel antibiotics against highly-resistant Gram-negative infections (GNIs) are scarce. We aimed to use real-world data from an electronic health record repository to identify treatment opportunities in US hospitals for GNIs resistant to all first-line drugs.

METHODS

For this retrospective cohort study, population estimates with an unmet need for novel Gram-negative antibiotics were quantified using the Cerner Health Facts database (2009-15), aggregating episodes of infection in US hospitals with pathogens displaying difficult-to-treat resistance (DTR; resistance to carbapenems, other β-lactams, and fluoroquinolones) and episodes involving empirical coverage with reserve drugs (colistin or polymyxin B and aminoglycosides). Episodes displaying extended-spectrum cephalosporin resistance (ECR) were also estimated. Episodes were multiplied by site-specific and fixed 14-day treatment durations for conservative and liberal days-of-therapy (DOT) estimates and stratified by site and taxon. Hospital type-specific DOT rates were reliability adjusted to account for random variation; cluster analyses quantified contribution from outbreaks.

FINDINGS

Across 2 996 271 inpatient encounters and 134 hospitals, there were 1352 DTR-GNI episodes, 1765 episodes involving empirical therapy with colistin or polymyxin B, and 16 632 episodes involving aminoglycosides. Collectively, these yielded 39·0 (conservative estimate) to 138·2 (liberal estimate) DOT per 10 000 encounters for a novel DTR-GNI-targeted drug, whereas greater treatment opportunities were identified for ECR (six times greater) and β-lactam susceptible GNIs (70 times greater). The most common DTR-GNI site and pathogen was lower respiratory (14·3 [43·3%] of 33 DOT per 10 000 encounters) and Pseudomonas aeruginosa (522 [38·1%] of 1371 episodes), whereas Enterobacteriaceae urinary-tract infections dominated the ECR or carbapenem-sparing niche (59·0% [5589 of 9535 episodes]) equating to 210·7 DOT per 10 000 encounters. DTR Stenotrophomonas maltophilia, Burkholderia spp, and Achromobacter spp represented less than 1 DOT per 10 000 encounters each. The estimated need for DTR-GNI-targeted antibiotics saw minor contributions by outbreaks and varied from 0·5 to 73·1 DOT per 10 000 encounters by hospital type.

INTERPRETATION

Suspected or documented GNIs with no or suboptimal treatment options are relatively infrequent. Non-revenue-based strategies and innovative trial designs are probably essential to the development of antibiotics with improved effectiveness for these GNIs.

FUNDING

Center for Drug Evaluation and Research, US Food and Drug Administration; Intramural Research Program, National Institutes of Health Clinical Center and the National Institute of Allergy and Infectious Diseases and the National Cancer Institute.

Clinical evaluation of cefotiam in the treatment of bacteremia caused by Escherichia coli, Klebsiella species, and Proteus mirabilis: A retrospective study

Bacteremia is often caused by gram-negative bacteria (represented by EKP; Escherichia coli, Klebsiella species, and Proteus mirabilis), and the excessive use of cefazolin, as the first-line antimicrobial in its treatment, has been a source of concern in the emergence of resistant strains. As an antimicrobial, cefotiam may be an alternative to cefazolin; however, little evidence is available for its use in the treatment of bacteremia. The purpose of this non-inferiority study was to retrospectively compare the therapeutic efficacy of cefotiam with some antimicrobials of narrow spectrum (cefazolin, cefmetazole, and flomoxef) in the treatment of EKP-induced bacteremia. The number of patients recruited was 32 in the cefotiam group and 29 in the control group. In the primary endpoint, the survival rate on day 28 for the cefotiam group and the control group was 93.5% and 89.3%, respectively (relative risk at day 28, 1.048; 95% confidence interval, 0.894-1.227). In the secondary end point, treatment success rate in the two groups was 71.9% and 69.0%, respectively (relative risk, 1.042; 95% confidence interval, 0.752-1.445). Intensive care unit admission, low body weight, hypoalbuminemia, and infections unassociated with the urinary tract were identified to be the risk factors responsible for treatment failure. We demonstrated cefotiam may be non-inferior to other antimicrobials of similar spectrum, in terms of survival rate, in EKP-induced bacteremia.