Ciprofloxacin and imipenem resistance and cross-resistance in Pseudomonas aeruginosa: A single institution experience

Eradication of Bacterial Persister Cells By Leveraging Their Low Metabolic Activity Using Adenosine Triphosphate Coated Gold Nanoclusters

Bacteria first develop tolerance after antibiotic exposure; later genetic resistance emerges through the population of tolerant bacteria. Bacterial persister cells are the multidrug-tolerant subpopulation within an isogenic bacteria culture that maintains genetic susceptibility to antibiotics. Because of this link between antibiotic tolerance and resistance and the rise of antibiotic resistance, there is a pressing need to develop treatments to eradicate persister cells. Current anti persister cell strategies are based on the paradigm of "awakening" them from their low metabolic state before attempting eradication with traditional antibiotics. Herein, we demonstrate that the low metabolic activity of persister cells can be exploited for eradication over their metabolically active counterparts. We engineered gold nanoclusters coated with adenosine triphosphate (AuNC@ATP) as a benchmark nanocluster that kills persister cells over exponential growth bacterial cells and prove the feasibility of this new concept. Finally, using AuNC@ATP as a new research tool, we demonstrated that it is possible to prevent the emergence of antibiotic-resistant superbugs with an anti-persister compound. Eradicating persister cells with AuNC@ATP in an isogenic culture of bacteria stops the emergence of superbug bacteria mediated by the sub-lethal dose of conventional antibiotics. Our findings lay the groundwork for developing novel nano-antibiotics targeting persister cells, which promise to prevent the emergence of superbugs and prolong the lifespan of currently available antibiotics.

Phenotypic and genotypic characterisation of cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacterial pathogens in Lebanon, Jordan and Iraq

Antimicrobial resistance (AMR) is a worldwide health concern that continues to escalate. A PubMed literature search identified articles from January 2015-August 2020 reviewing cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacteria (GNB) in Lebanon, Jordan and Iraq, specifically focused on three main pathogens, namely Acinetobacter spp., Enterobacteriaceae (i.e. Escherichia coli and Klebsiella spp.) and Pseudomonas aeruginosa. Sixty-seven relevant articles published within the past 5 years highlighting trends in AMR in Lebanon, Jordan and Iraq were included. Increased resistance to carbapenems in Acinetobacter spp. isolates was observed in Lebanon, Jordan and Iraq; colistin resistance remained relatively low. Studies on Enterobacteriaceae isolates were more varied, with high rates of carbapenem and cephalosporin resistance and lower levels of colistin resistance in Lebanon. Studies from Iraq found high cephalosporin and colistin resistance along with increased susceptibility to carbapenems. In Jordan, most studies recorded high resistance to cephalosporins along with high susceptibility to carbapenems and colistin. Studies on P. aeruginosa isolates were limited: most isolates in Lebanon were carbapenem-resistant and colistin-susceptible; studies in Iraq showed varying levels of resistance to carbapenems and cephalosporins with high susceptibility to colistin; and studies in Jordan found varying levels of susceptibility to carbapenems, cephalosporins and colistin. The most commonly observed resistance mechanisms in GNB were genetic modifications causing increased expression of antimicrobial-inactivating enzymes and decreased permeability. Overall, this review highlights the concerning rise in AMR and the need for improved understanding of the resistance mechanisms to better inform healthcare providers when recommending treatment for patients in this region.

The 2018 Lebanese Society of Infectious Diseases and Clinical Microbiology Guidelines for the use of antimicrobial therapy in complicated intra-abdominal infections in the era of antimicrobial resistance

BACKGROUND

The Lebanese Society of Infectious Diseases and Clinical Microbiology (LSIDCM) is involved in antimicrobial stewardship. In an attempt at guiding clinicians across Lebanon in regards to the proper use of antimicrobial agents, members of this society are in the process of preparing national guidelines for common infectious diseases, among which are the guidelines for empiric and targeted antimicrobial therapy of complicated intra-abdominal infections (cIAI). The aims of these guidelines are optimizing patient care based on evidence-based literature and local antimicrobial susceptibility data, together with limiting the inappropriate use of antimicrobials thus decreasing the emergence of antimicrobial resistance (AMR) and curtailing on other adverse outcomes.

METHODS

Recommendations in these guidelines are adapted from other international guidelines but modeled based on locally derived susceptibility data and on the availability of pharmaceutical and other resources.

RESULTS

These guidelines propose antimicrobial therapy of cIAI in adults based on risk factors, site of acquisition of infection, and clinical severity of illness. We recommend using antibiotic therapy targeting third-generation cephalosporin (3GC)-resistant gram negative organisms, with carbapenem sparing as much as possible, for community-acquired infections when the following risk factors exist: prior (within 90 days) exposure to antibiotics, immunocompromised state, recent history of hospitalization or of surgery and invasive procedure all within the preceding 90 days. We also recommend antimicrobial de-escalation strategy after culture results. Prompt and adequate antimicrobial therapy for cIAI reduces morbidity and mortality; however, the duration of therapy should be limited to no more than 4 days when adequate source control is achieved and the patient is clinically stable. The management of acute pancreatitis is conservative, with a role for antibiotic therapy only in specific situations and after microbiological diagnosis. The use of broad-spectrum antimicrobial agents including systemic antifungals and newly approved antibiotics is preferably restricted to infectious diseases specialists.

CONCLUSION

These guidelines represent a major step towards initiating a Lebanese national antimicrobial stewardship program. The LSIDCM emphasizes on development of a national AMR surveillance network, in addition to a national antibiogram for cIAI stratified based on the setting (community, hospital, unit-based) that should be frequently updated.

Epidemiology of common resistant bacterial pathogens in the countries of the Arab League

No uniformly organised collection of data regarding antimicrobial resistance has occurred in the countries of the Arab League. 19 countries of the Arab League have published data for antimicrobial susceptibility for the WHO priority organisms, and seven of 14 of these organisms are included in this Review (Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella spp, Staphylococcus aureus, and Streptococcus pneumoniae). Although E coli and Klebsiella spp resistance to third-generation cephalosporins is common in all countries, with prevalence reaching more than 50% in Egypt and Syria, carbapenem resistance is emerging, albeit with a prevalence of less than 10%. Conversely, a large amount of carbapenem resistance has been reported for P aeruginosa and A baumannii across the Arab League, reaching 50% and 88% of isolates in some countries. As for Salmonella spp, the prevalence of fluoroquinolone resistance has exceeded 30% in several areas. With regards to the Gram-positive pathogens, the prevalence of meticillin resistance in S aureus is reported to be between 20% and 30% in most countries, but exceeds 60% in Egypt and Iraq. The prevalence of penicillin non-susceptibility among pneumococci has reached more than 20% in Algeria, Egypt, Morocco, Saudi Arabia, and Tunisia. These findings highlight the need for structured national plans in the region to target infection prevention and antimicrobial stewardship.

Recent updates of carbapenem antibiotics

Carbapenems are among the most commonly used and the most efficient antibiotics since they are relatively resistant to hydrolysis by most β-lactamases, they target penicillin-binding proteins, and generally have broad-spectrum antibacterial effect. In this review, we described the initial discovery and development of carbapenems, chemical characteristics, in vitro/in vivo activities, resistance studies, and clinical investigations for traditional carbapenem antibiotics in the market; imipenem-cilastatin, meropenem, ertapenem, doripenem, biapenem, panipenem/betamipron in addition to newer carbapenems such as razupenem, tebipenem, tomopenem, and sanfetrinem. We focused on the literature published from 2010 to 2016.