Antibiotic multi-drug-resistance of Escherichia coli causing device- and procedure-related infections in the United States reported to the National Healthcare Safety Network (NHSN), 2013-2017

Comprehensive characterization of bacterial glycoconjugate vaccines by liquid chromatography - mass spectrometry

Bacterial pathogens can cause a broad range of infections with detrimental effects on health. Vaccine development is essential as multi-drug resistance in bacterial infections is a rising concern. Recombinantly produced proteins carrying O-antigen glycosylation are promising glycoconjugate vaccine candidates to prevent bacterial infections. However, methods for their comprehensive structural characterization are lacking. Here, we present a bottom-up approach for their site-specific characterization, detecting N-glycopeptides by nano reversed-phase liquid chromatography-mass spectrometry (RP-LC-MS). Glycopeptide analyses revealed information on partial site-occupancy and site-specific glycosylation heterogeneity and helped corroborate the polysaccharide structures and their modifications. Bottom-up analysis was complemented by intact glycoprotein analysis using nano RP-LC-MS allowing the fast visualization of the polysaccharide distribution in the intact glycoconjugate. At the glycopeptide level, the model glycoconjugates analyzed showed different repeat unit (RU) distributions that spanned from 1 to 21 RUs attached to each of the different glycosylation sites. Interestingly, the intact glycoprotein analysis displayed a RU distribution ranging from 1 to 28 RUs, showing the predominant species when the different glycopeptide distributions are combined in the intact glycoconjugate. The complete workflow based on LC-MS measurements allows detailed and comprehensive analysis of the glycosylation state of glycoconjugate vaccines.

Phosphonium-Substituted Conjugated Polyelectrolytes Display Efficient Visible-Light-Induced Antibacterial Activity

We report the light-activated antibacterial activity of a new class of phosphonium (R-PMe3+)-substituted conjugated polyelectrolytes (CPEs). These polyelectrolytes feature a poly(phenylene ethynylene) (PPE) conjugated backbone substituted with side groups with the structure -O-(CH2)nPMe3+, where n = 3 or 6. The length of the side groups has an effect on the hydrophobic character of the CPEs and their propensity to interact with bacterial membranes. In a separate study, these phosphonium-substituted PPE CPEs were demonstrated to photosensitize singlet oxygen (1O2) and reactive oxygen species, a key factor for the photoinduced inactivation of bacteria. In this study, in vitro antibacterial assays against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were performed by employing the series of polyelectrolytes under both dark and illumination conditions. In general, the phosphonium-substituted CPEs displayed profound light-activated biocidal activity, with >99% colony forming unit (CFU) reduction after 15 min of light exposure (16 mW cm-2) at a ≤20 μM CPE concentration. Strong biocidal activity was also observed in the dark for a CPE concentration of 20 μM against S. aureus; however, higher concentrations (200 μM) were needed to enable dark inactivation of E. coli. The dark activity is ascribed to bacterial membrane disruption by the CPEs, supported by a correlation of dark biocidal activity with the chain length of the side groups. The light-activated biocidal activity is associated with the ability of the CPEs to sensitize ROS, which is cytotoxic to the microorganisms. Serial dilution bacterial plating experiments revealed that the series of CPEs was able to induce a >5-log kill versus E. coli with 15 min of exposure to a blue LED source (16 mW cm-2).

Clinical and epidemiological characteristics of multi-drug resistant Enterobacterales isolated from King Fahad Hospital of the University, AlKhobar, Saudi Arabia

Multi-drug resistant (MDR) Enterobacterales remain a major clinical problem. Infections caused by carbapenem-resistant strains are particularly difficult to treat. This study aimed to assess the clinical and epidemiological characteristics of MDR Enterobacterales isolates. A total of 154 non-repetitive clinical isolates, including Escherichia coli (n = 66), Klebsiella pneumoniae (n = 70), and other Enterobacterales (n = 18), were collected from the Diagnostic Microbiology Laboratory at King Fahad Hospital of the University. Most E. coli isolates were collected from urine specimens (n = 50, 75.8%) and resistance against the third and fourth-generation cephalosporins (ceftriaxone, ceftazidime, cefixime, and cefepime) and fluoroquinolones (ciprofloxacin and levofloxacin) was assessed. Clonal relatedness analysis using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) revealed two clones (E. coli A and B), each comprising two strains. Most K. pneumoniae samples were collected from respiratory specimens (27.1%, 20 samples), and the strains showed overall resistance to most of the antimicrobials tested (54%‒100%). Moreover, clonal-relatedness analysis using ERIC-PCR revealed seven major clones of K. pneumoniae. These findings suggest nosocomial transmission among some identical strains and emphasize the importance of strict compliance with infection prevention and control policies and regulations. Environmental reservoirs could facilitate this indirect transmission, which needs to be investigated.

Insights into the microbiological and virulence characteristics of bacteria in orthopaedic implant infections: A study from Pakistan

The exponential increase in the prevalence of multidrug resistant bacteria has resulted in limiting surgical treatment options globally, potentially causing biofilm-related complications, implant failure, and severe consequences. This study aims to isolate and characterize bacteria from post-surgical orthopaedic implant infections and screening for multiple antibiotic resistance. A cross-sectional study was conducted, involving isolation of forty-four dominant pathogenic bacterial isolates from 16 infected implant samples from across Islamabad and Rawalpindi. Out of forty-four, 38% cocci and 61% bacilli were obtained. Approximately 90% of isolates showed multiple antibiotic resistance (MAR) index of more than 0.2. Eleven strains were identified via 16S rRNA gene sequencing as Pseudomonas aeruginosa, Bacillus spp., Planococcus chinensis, Staphylococcus, Escherichia coli and Enterobacter cloacae. The bacterial strain E. coli MB641 showed sensitivity to Polymyxin only, and was resistant to all other antibiotics used. Maximum biofilm forming ability 0.532 ± 0.06, 0.55 ± 0.01 and 0.557 ± 0.07 was observed in Pseudomonas aeruginosa MB663, Pseudomonas aeruginosa MB664 and Bacillus spp. MB647 respectively after 24 hours of incubation. EPS production of bacterial strains was assessed, the polysaccharides and protein content of EPS were found to be in the range of 11-32 μg/ml and 2-10 μg/ml, respectively. Fourier transform infrared spectroscopic analysis of EPS showed the presence of carbohydrates, proteins, alkyl halides, and nucleic acids. X-ray diffraction analysis revealed crystalline structure of EPS extracted from biofilm forming bacteria. These findings suggest a high prevalence of antibiotic-resistant bacteria in orthopaedic implant-associated surgeries, highlighting the urgent need for ongoing monitoring and microorganism testing in infected implants.

Antimicrobial Resistance Patterns and Risk Factors Associated with ESBL-Producing and MDR Escherichia coli in Hospital and Environmental Settings in Lusaka, Zambia: Implications for One Health, Antimicrobial Stewardship and Surveillance Systems

Antimicrobial resistance (AMR) is a public health problem threatening human, animal, and environmental safety. This study assessed the AMR profiles and risk factors associated with Escherichia coli in hospital and environmental settings in Lusaka, Zambia. This cross-sectional study was conducted from April 2022 to August 2022 using 980 samples collected from clinical and environmental settings. Antimicrobial susceptibility testing was conducted using BD PhoenixTM 100. The data were analysed using SPSS version 26.0. Of the 980 samples, 51% were from environmental sources. Overall, 64.5% of the samples tested positive for E. coli, of which 52.5% were from clinical sources. Additionally, 31.8% were ESBL, of which 70.1% were clinical isolates. Of the 632 isolates, 48.3% were MDR. Most clinical isolates were resistant to ampicillin (83.4%), sulfamethoxazole/trimethoprim (73.8%), and ciprofloxacin (65.7%) while all environmental isolates were resistant to sulfamethoxazole/trimethoprim (100%) and some were resistant to levofloxacin (30.6%). The drivers of MDR in the tested isolates included pus (AOR = 4.6, CI: 1.9-11.3), male sex (AOR = 2.1, CI: 1.2-3.9), and water (AOR = 2.6, CI: 1.2-5.8). This study found that E. coli isolates were resistant to common antibiotics used in humans. The presence of MDR isolates is a public health concern and calls for vigorous infection prevention measures and surveillance to reduce AMR and its burdens.

Older patient age and prior antimicrobial use strongly predict antimicrobial resistance in Escherichia coli isolates recovered from urinary tract infections among female outpatients

BACKGROUND

Increasing prevalence of antimicrobial resistance (AMR), including multidrug resistance (MDR), among Escherichia coli (E. coli) makes treatment of uncomplicated urinary tract infection (uUTI) difficult. We assessed risk factors for fluoroquinolone (FQ)-not-susceptible (NS) and MDR E. coli among US female outpatients.

METHODS

This retrospective cohort study utilized data from female outpatients aged ≥ 12 years with E. coli positive urine culture and oral antimicrobial prescription ± 1 day from index. We assessed patient-level factors within 90 and 91-360 days prior to index as predictors of FQ NS (intermediate/resistant) and MDR (NS to ≥ 1 drug across ≥ 3 classes) E. coli: age, prior oral antimicrobial dispensing, prior AMR phenotypes, prior urine culture, and prior hospitalization.

RESULTS

Among 1,858 outpatients with urine-isolated E. coli, 369 (19.9%) had FQ NS and 59 (3.2%) had MDR isolates. After multivariable adjustment, independent risk factors (p < 0.03) for FQ NS E. coli were older age, prior FQ NS isolates, prior dispensing of FQ, and dispensing of any oral antibiotic. Independent risk factors (p < 0.02) for MDR were prior extended-spectrum β-lactamase-producing isolates (ESBL+), prior FQ dispensing, and prior oral antibiotic dispensing.

CONCLUSIONS

In women with uUTI due to E. coli, prior dispensing of FQ or any oral antibiotic within 90 days predicted FQ NS and MDR urine E. coli. Prior urine culture with FQ NS isolates and older age were predictive of FQ NS E. coli. Prior ESBL+ was predictive of MDR E. coli. These data could help identify patients at risk for AMR E. coli and inform empiric prescribing.

A one-year genomic investigation of Escherichia coli epidemiology and nosocomial spread at a large US healthcare network

BACKGROUND

Extra-intestinal pathogenic Escherichia coli (ExPEC) are a leading cause of bloodstream and urinary tract infections worldwide. Over the last two decades, increased rates of antibiotic resistance in E. coli have been reported, further complicating treatment. Worryingly, specific lineages expressing extended-spectrum β-lactamases (ESBLs) and fluoroquinolone resistance have proliferated and are now considered a serious threat. Obtaining contemporary information on the epidemiology and prevalence of these circulating lineages is critical for containing their spread globally and within the clinic.

METHODS

Whole-genome sequencing (WGS), phylogenetic analysis, and antibiotic susceptibility testing were performed for a complete set of 2075 E. coli clinical isolates collected from 1776 patients at a large tertiary healthcare network in the USA between October 2019 and September 2020.

RESULTS

The isolates represented two main phylogenetic groups, B2 and D, with six lineages accounting for 53% of strains: ST-69, ST-73, ST-95, ST-131, ST-127, and ST-1193. Twenty-seven percent of the primary isolates were multidrug resistant (MDR) and 5% carried an ESBL gene. Importantly, 74% of the ESBL-E.coli were co-resistant to fluoroquinolones and mostly belonged to pandemic ST-131 and emerging ST-1193. SNP-based detection of possible outbreaks identified 95 potential transmission clusters totaling 258 isolates (12% of the whole population) from ≥ 2 patients. While the proportion of MDR isolates was enriched in the set of putative transmission isolates compared to sporadic infections (35 vs 27%, p = 0.007), a large fraction (61%) of the predicted outbreaks (including the largest cluster grouping isolates from 12 patients) were caused by the transmission of non-MDR clones.

CONCLUSION

By coupling in-depth genomic characterization with a complete sampling of clinical isolates for a full year, this study provides a rare and contemporary survey on the epidemiology and spread of E. coli in a large US healthcare network. While surveillance and infection control efforts often focus on ESBL and MDR lineages, our findings reveal that non-MDR isolates represent a large burden of infections, including those of predicted nosocomial origins. This increased awareness is key for implementing effective WGS-based surveillance as a routine technology for infection control.

A case–control study of infections caused by Klebsiella pneumoniae producing New Delhi metallo-beta-lactamase-1: Predictors and outcomes

Introduction

Infections caused by antimicrobial-resistant bacteria are a significant cause of death worldwide, and carbapenemase-producing bacteria are the principal agents. New Delhi metallo-beta-lactamase-1 producing Klebsiella pneumoniae (KP-NDM-1) is an extensively drug-resistant bacterium that has been previously reported in Mexico. Our aim was to conduct a case–control study to describe the risk factors associated with nosocomial infections caused by K. pneumoniae producing NDM-1 in a tertiary-care hospital in Mexico.

Methods

A retrospective case–control study with patients hospitalized from January 2012 to February 2018 at the Hospital Civil de Guadalajara “Fray Antonio Alcalde” was designed. During this period, 139 patients with a culture that was positive for K. pneumoniae NDM-1 (cases) and 486 patients hospitalized in the same department and on the same date as the cases (controls) were included. Data were analyzed using SPSS v. 24, and logistic regression analysis was conducted to calculate the risk factors for KP-NDM-1 infection.

Results

One hundred and thirty-nine case patients with a KP-NDM-1 isolate and 486 control patients were analyzed. In the case group, acute renal failure was a significant comorbidity, hospitalization days were extended, and significantly more deaths occurred. In a multivariate analysis of risk factors, the independent variables included the previous use of antibiotics (odds ratio, OR = 12.252), the use of a urinary catheter (OR = 5.985), the use of a central venous catheter (OR = 5.518), the use of mechanical ventilation (OR = 3.459), and the length of intensive care unit (ICU) stay (OR = 2.334) as predictors of infection with NDM-1 K. pneumoniae.

Conclusion

In this study, the previous use of antibiotics, the use of a urinary catheter, the use of a central venous catheter, the use of mechanical ventilation, and ICU stay were shown to be predictors of infection with NDM-1 K. pneumoniae and were independent risk factors for infection with NDM-1 K. pneumoniae.

Rise in the prevalence of resistance to extended-spectrum cephalosporins in the USA, nursing homes and antibiotic prescribing in outpatient and inpatient settings

The prevalence of resistance to extended-spectrum (ES) cephalosporins for multiple types of infections treated in US hospitals and the incidence of hospitalization with ESBL-producing Enterobacteriaceae (many of which are detected in nursing home residents) have grown markedly in recent years. Here, I review these developments, as well as evidence for their adverse consequences, including the increase in the overall burden of bacterial infections due to proliferation of ESBL-producing/ES cephalosporin-resistant bacteria, the contribution of ESBL-producing/ES cephalosporin-resistant bacteria to the increase in the burden of mortality associated with bacterial infections and the contribution of the proliferation of ESBL-producing bacteria to the prevalence of carbapenem resistance. I argue that in order to mitigate the escalation of these phenomena, a reduction in outpatient prescribing of cephalosporins, especially to older adults, mitigation of transmission of ESBL-producing organisms in nursing homes and a reduction in inpatient prescribing of ES cephalosporins (which has seen a major increase in recent years) are needed.