In vitro Activity of Ceftazidime-Avibactam and Aztreonam-Avibactam Against Carbapenem-resistant Enterobacteriaceae Isolates Collected from Three Secondary Hospitals in Southwest China Between 2018 and 2019
INFECTION AND DRUG RESISTANCE
Authors: Zou, Chunhong; Wei, Jie; Shan, Baoju; Chen, Xian; Wang, Deqiang; Niu, Siqiang
Abstract
Purpose: To assess the antimicrobial activities of ceftazidime/avibactam (CAZ/AVI) and aztreonam/avibactam (ATM/AVI) against carbapenem-resistant Enterobacteriaceae (CRE) isolates collected from three secondary hospitals in Southwest China between 2018 and 2019. Materials and Methods: A total of 120 unique CRE clinical isolates were collected and carbapenemase genes were detected using PCR. Antimicrobial susceptibility was determined using standard broth microdilution method and the results were interpreted according to CLSI breakpoints. Results: The 120 carbapenem-resistant strains included 92 Klebsiella pneumoniae, 10 Escherichia coli, 10 Enterobacter cloacae, five Klebsiella aerogenes, and three Klebsiella oxytoca isolates. Seventy-four percent of these 120 CRE isolates were collected from patients located in non-ICUs; 65.0% of these CRE isolates were collected from male patients; and 34.2% of these isolates were isolated from respiratory tracts. Four different carbapenemase genes were identified among 103 carbapenemase-producing Enterobacteriaceae (CPE) isolates, including bla(KPC-2) (n=77), bla(NDM-1) (n=16), bla(NDM-5) (n=12) and bla(IMP-4) (n=2). Overall, 21.7%, 37.5%, 40.8%, 75.0%, and 100% of the CRE strains were susceptible to levofloxacin, trimethoprim/sulfamethoxazole, amikacin, CAZ/AVI, and ATM/AVI, respectively. In addition, antimicrobial susceptibility testing showed that 96.7% isolates (n=116) were resistant to aztreonam, and the addition of avibactam (4 mg/L) significantly reduced the MICs of those aztreonam-resistant isolates by more than 128-fold (range: <= 0.125-4 mg/L), and 90.0% (n=108) of total 120 isolates were inhibited at ATM/AVI concentration <= 1 mg/L. Conclusion: Our study revealed significant antimicrobial resistance among the CRE isolates against some commonly used antibiotics in three secondary Chinese hospitals. ATM/AVI exhibited potent activity against CRE isolates, including double carbapenemase-producing isolates, whereas CAZ/AVI was active against all KPC producers.
The Role of Systemic Antimicrobials in the Treatment of Endophthalmitis: A Review and an International Perspective
OPHTHALMOLOGY AND THERAPY
Authors: Grzybowski, Andrzej; Turczynowska, Magdalena; Schwartz, Stephen G.; Relhan, Nidhi; Flynn, Harry W., Jr.
Abstract
Background The optimal management of patients with endophthalmitis is challenging and includes both intravitreal and, in some cases, systemic antimicrobials. Systemic antimicrobials may be administered either intravenously or orally. In this article we review systemic antimicrobial options currently available for the treatment of types of endophthalmitis and the role of systemic antimicrobials (antibiotics and antifungals) in these treatments. Review While systemic antimicrobials are not universally utilized in the management of endophthalmitis, they may be helpful in some circumstances. The blood-retinal barrier affects the penetration of systemic medications into the posterior segment of the eye differently; for example, moxifloxacin and imipenem cross the blood-retinal barrier relatively easily while vancomycin and amikacin do not. However, inflammation, including endophthalmitis, may disrupt the blood-retinal barrier, enhancing the penetration of systemic agents into the eye. Conclusion Systemic antimicrobials may be particularly beneficial in patients with certain types of endophthalmitis; as such, they are standard treatment in the management of endogenous endophthalmitis (fungal and bacterial) and also widely used for prophylaxis and treatment of open-globe injuries. Although systemic antimicrobials are used in some patients with acute-onset postoperative endophthalmitis following cataract surgery, the literature generally does not support this practice. It is noted that there are currently no randomized clinical trials demonstrating a benefit of systemic antibiotics for any category of endophthalmitis.