Les misérables: a Parallel Between Antimicrobial Resistance and COVID-19 in Underdeveloped and Developing Countries

Combined effect of SAR-endolysin LysKpV475 with polymyxin B and Salmonella bacteriophage phSE-5

Endolysins are bacteriophage (or phage)-encoded enzymes that catalyse the peptidoglycan breakdown in the bacterial cell wall. The exogenous action of recombinant phage endolysins against Gram-positive organisms has been extensively studied. However, the outer membrane acts as a physical barrier when considering the use of recombinant endolysins to combat Gram-negative bacteria. This study aimed to evaluate the antimicrobial activity of the SAR-endolysin LysKpV475 against Gram-negative bacteria as single or combined therapies, using an outer membrane permeabilizer (polymyxin B) and a phage, free or immobilized in a pullulan matrix. In the first step, the endolysin LysKpV475 in solution, alone and combined with polymyxin B, was tested in vitro and in vivo against ten Gram-negative bacteria, including highly virulent strains and multidrug-resistant isolates. In the second step, the lyophilized LysKpV475 endolysin was combined with the phage phSE-5 and investigated, free or immobilized in a pullulan matrix, against Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311. The bacteriostatic action of purified LysKpV475 varied between 8.125 μg ml-1 against Pseudomonas aeruginosa ATCC 27853, 16.25 μg ml-1 against S. enterica Typhimurium ATCC 13311, and 32.50 μg ml-1 against Klebsiella pneumoniae ATCC BAA-2146 and Enterobacter cloacae P2224. LysKpV475 showed bactericidal activity only for P. aeruginosa ATCC 27853 (32.50 μg ml-1) and P. aeruginosa P2307 (65.00 μg ml-1) at the tested concentrations. The effect of the LysKpV475 combined with polymyxin B increased against K. pneumoniae ATCC BAA-2146 [fractional inhibitory concentration index (FICI) 0.34; a value lower than 1.0 indicates an additive/combined effect] and S. enterica Typhimurium ATCC 13311 (FICI 0.93). A synergistic effect against S. enterica Typhimurium was also observed when the lyophilized LysKpV475 at ⅔ MIC was combined with the phage phSE-5 (m.o.i. of 100). The lyophilized LysKpV475 immobilized in a pullulan matrix maintained a significant Salmonella reduction of 2 logs after 6 h of treatment. These results demonstrate the potential of SAR-endolysins, alone or in combination with other treatments, in the free form or immobilized in solid matrices, which paves the way for their application in different areas, such as in biocontrol at the food processing stage, biosanitation of food contact surfaces and biopreservation of processed food in active food packing.

Pre- and Post-COVID-19 Antimicrobial Resistance Pattern of Pathogens in an Intensive Care Unit

We aimed to determine the trend of the antimicrobial resistance pattern of pathogens isolated in samples collected from patients hospitalized in the intensive care unit (ICU) in selected periods before and after COVID-19. A retrospective study of bacterial pathogens was performed on 1267 patients. Positive bacterial culture data from 1695 samples from the pre-COVID-19 period and 1562 samples from the post-COVID-19 period were obtained. The most frequently isolated bacteria in both periods were Staphylococcus aureus and Klebsiella spp. The resistance rates of Klebsiella spp. Significantly increased against colistin (0.38% to 20.51%), gentamicin (44.62% to 64.85%), and aztreonam (56.35% to 3.60%). There was a significant increase in the resistance rate against colistin for E. coli strains (4.69% to 32.46%) and for Acinetobacter sp. strains (3.37% to 18.09%). More than 50% of the Staphylococcus aureus strains were MRSA, with statistically significant increases in the antimicrobial resistance rate against doxycycline (40.08% to 51.72%), linezolid (0.22% to 3.13%), rifampicin (53.16% to 64.93%), and teicoplanin (26.31% to 53.40%). The study revealed a significantly increasing trend in the antimicrobial resistance rate of Gram-negative pathogens against certain antibiotics, including those used only in cases where there are no other therapeutic options.

Genetic diversity of macrolides resistant Staphylococcus aureus clinical isolates and the potential synergistic effect of vitamins, C and K3

BACKGROUND

Macrolide antibiotics have been extensively used for the treatment of Staphylococcus aureus infections. However, the emergence of macrolide-resistant strains of S. aureus has become a major concern for public health. The molecular mechanisms underlying macrolide resistance in S. aureus are complex and diverse, involving both target site modification and efflux pump systems. In this study, we aim to overcome the molecular diversity of macrolide resistance mechanisms in S. aureus by identifying common molecular targets that could be exploited for the development of novel therapeutics.

METHODS

About 300 Staphylococcus aureus different isolates were recovered and purified from 921 clinical specimen including urine (88), blood (156), sputum (264), nasal swabs (168), pus (181) and bone (39) collected from different departments in Tanta University Hospital. Macrolide resistant isolates were detected and tested for Multi Drug Resistant (MDR). Gel electrophoresis was performed after the D test and PCR reaction for erm(A), (B), (C), msr(A), and mph(C) genes. Finally, we tried different combinations of Erythromycin or Azithromycin antibiotics with either vitamin K3 or vitamin C.

RESULTS

Macrolide resistance S. aureus isolates exhibited 7 major resistance patterns according to number of resistance markers and each pattern included sub patterns or subgroups. The PCR amplified products of different erm genes; analysis recorded different phenotypes of the Staphylococcus aureus isolates according to their different genotypes. In addition, our new tested combinations of Erythromycin and vitamin C, Erythromycin, and vitamin K3, Azithromycin and vitamin C and Azithromycin and vitamin K3 showed significant antibacterial effect when using every antibiotic alone. Our findings provide new insights into the molecular mechanisms of macrolide resistance in S. aureus and offer potential strategies for the development of novel protocols to overcome this emerging public health threat.

[Study of the resistome of human microbial communities using a targeted panel of antibiotic resistance genes in COVID-19 patients]

AIM

To study overall drug resistance genes (resistome) in the human gut microbiome and the changes in these genes during COVID-19 in-hospital therapy.

MATERIALS AND METHODS

A single-center retrospective cohort study was conducted. Only cases with laboratory-confirmed SARS-CoV-2 RNA using polymerase chain reaction in oro-/nasopharyngeal swab samples were subject to analysis. The patients with a documented history of or current comorbidities of the hepatobiliary system, malignant neoplasms of any localization, systemic and autoimmune diseases, as well as pregnant women were excluded. Feces were collected from all study subjects for subsequent metagenomic sequencing. The final cohort was divided into two groups depending on the disease severity: mild (group 1) and severe (group 2). Within group 2, five subgroups were formed, depending on the use of antibacterial drugs (ABD): group 2A (receiving ABD), group 2AC (receiving ABD before hospitalization), group 2AD (receiving ABD during hospitalization), group 2AE (receiving ABD during and before hospitalization), group 2B (not receiving ABD).

RESULTS

The median number of antibiotic resistance (ABR) genes (cumulative at all time points) was significantly higher in the group of patients treated with ABD: 81.0 (95% CI 73.8-84.5) vs. 51.0 (95% CI 31.1-68.4). In the group of patients treated with ABD (2A), the average number of multidrug resistance genes (efflux systems) was significantly higher than in controls (group 2B): 47.0 (95% CI 46.0-51.2) vs. 21.5 (95% CI 7.0-43.9). Patients with severe coronavirus infection tended to have a higher median number of ABR genes but without statistical significance. Patients in the severe COVID-19 group who did not receive ABD before and during hospitalization also had more resistance genes than the patients in the comparison group.

CONCLUSION

This study demonstrated that fewer ABR genes were identified in the group with a milder disease than in the group with a more severe disease associated with more ABR genes, with the following five being the most common: SULI, MSRC, ACRE, EFMA, SAT.

Antibiotic-Resistant ESKAPE Pathogens and COVID-19: The Pandemic beyond the Pandemic

Antibacterial resistance is a renewed public health plague in modern times, and the COVID-19 pandemic has rekindled this problem. Changes in antibiotic prescribing behavior, misinformation, financial hardship, environmental impact, and governance gaps have generally enhanced the misuse and improper access to antibiotics during the COVID-19 pandemic. These determinants, intersected with antibacterial resistance in the current pandemic, may amplify the potential for a future antibacterial resistance pandemic. The occurrence of infections with multidrug-resistant (MDR), extensively drug-resistant (XDR), difficult-to-treat drug-resistant (DTR), carbapenem-resistant (CR), and pan-drug-resistant (PDR) bacteria is still increasing. The aim of this review is to highlight the state of the art of antibacterial resistance worldwide, focusing on the most important pathogens, namely Enterobacterales, Acinetobacter baumannii, and Klebsiella pneumoniae, and their resistance to the most common antibiotics.

A Tale of Two Pandemics: Antimicrobial Resistance Patterns of Enterococcus spp. in COVID-19 Era

Although the COVID-19 pandemic has held the spotlight over the past years, the antimicrobial resistance (AMR) phenomenon continues to develop in an alarming manner. The lack of strict antibiotic regulation added to the overuse of antimicrobials fueled the AMR pandemic. This paper aims to analyze and identify the impact of the COVID-19 pandemic on antibiotic resistance patterns of Enterococcus spp. The study was designed as a retrospective observational study. Enterococcus spp. infections data were collected from one academic hospital in Cluj-Napoca, Romania over 18 months. A statistical analysis was performed to compare antibiotic resistance phenotypes identified. We recorded an increase in the isolation rates of Enterococcus spp. strains, from 26 isolates (26.53%) during Period A (November 2020-April 2021) to 42 strains (42.85%) during Period C (November 2021-April 2022). The number of strains with resistance to vancomycin increased from 8 during Period A to 17 during Period C. Of the total 36 strains with resistance to vancomycin, 25 were identified as E. faecium. SARS-CoV-2 patients (n = 29) proved to be at risk to develop an E. faecium co-infection (n = 18). We observed that strains with resistance to ampicillin (n = 20) and vancomycin (n = 15) are more often isolated from these patients. All changes identified in our study are to be considered in the light of COVID-19 pandemic, highlighting the threatening AMR phenomenon in Romania. Further studies should be performed to quantify the worldwide effects of these pandemics.