Emergence of colistin-resistant Klebsiella pneumoniae in Poland

Virulence analysis and antibiotic resistance of Klebsiella pneumoniae isolates from hospitalised patients in Poland

Klebsiella pneumoniae (KP) is a nosocomial pathogen causing difficult-to-treat infections. The presence of virulence genes and antibiotic resistance of 109 KP isolates from hospitalized patients were investigated. Among them, 68.8% were multi-drug resistant (MDR) and 59.6% produced extended-spectrum beta-lactamases (ESBLs). Metallo-β-lactamases (MBLs) were produced by 22% of isolates (mainly from anus), including 16.5% of isolates producing New Delhi metallo-β-lactamase (NDM-1). The genes encoding adhesins (fimH-91.7%, mrkD-96.3%), enterobactin (entB-100%) and yersiniabactin (irp-1-88%) were frequently identified. The genes encoding salmochelin (iroD-9.2%, iroN-7.3%) and colibactin (clbA, clbB-0.9%) were identified rarely. Iron acquisition system-related kfu gene and wcaG gene involved in capsule production were identified in 6.4% and 11% of isolates, respectively. The rmpA gene associated with hypermucoviscosity was present in 6.4% of isolates. In 19.2% of isolates magA gene was detected, specific for K1 capsule serotype, while 22.9% of isolates showed K2 capsule serotype. The rmpA, iroD or iroN genes being diagnostic biomarkers for hypervirulent KP (hvKP) were detected in 16.5% of isolates. We found that 55.5% of hvKP were MDR and produced ESBLs, thus hospital KP isolates pose a serious threat to the healthcare system.

A Bibliometric Meta-Analysis of Colistin Resistance in Klebsiella pneumoniae

Colistin is a last resort antibiotic medication for the treatment of infections caused by carbapenem-resistant Klebsiella pneumoniae. In recent years, various mechanisms have been reported to mediate colistin resistance in K. pneumoniae. This study reports a bibliometric analysis of published articles retrieved from the Scopus database relating to colistin resistance in K. pneumoniae. The research trends in colistin resistance and mechanisms of resistance were considered. A total of 1819 research articles published between 1995 and 2019 were retrieved, and the results indicated that 50.19% of the documents were published within 2017-2019. The USA had the highest participation with 340 (14.31%) articles and 14087 (17.61%) citations. Classification based on the WHO global epidemiological regions showed that the European Region contributed 42% of the articles while the American Region contributed 21%. The result further indicated that 45 countries had published at least 10 documents with strong international collaborations amounting to 272 links and a total linkage strength of 735. A total of 2282 keywords were retrieved; however, 57 keywords had ≥15 occurrences with 764 links and a total linkage strength of 2388. Furthermore, mcr-1, colistin resistance, NDM, mgrB, ceftazidime-avibactam, MDR, combination therapy, and carbapenem-resistant Enterobacteriaceae were the trending keywords. Concerning funders, the USA National Institute of Health funded 9.1% of the total research articles, topping the list. The analysis indicated poor research output, collaboration, and funding from Africa and South-East Asia and demands for improvement in international research collaboration.

Comparison of the recommended colistin susceptibility testing methods with colistin gradient strips and semi-automated method for antimicrobial-resistant non-fermenting rods

An increased frequency of multidrug-resistant non-fermenting rods isolation has resulted in the excessive use of colistin - often the last chance antimicrobial. However, determination of colistin susceptibility is difficult, mainly because of its structure and limited diffusion properties. This study was performed to compare colistin susceptibility testing among Pseudomonas aeruginosa (n = 49) and Acinetobacter baumannii (n = 49) strains. Four methods were applied: colistin gradient strips (Liofilchem, Italy), semi-automated method Phoenix BD (Becton Dickinson, USA) and two broth microdilution methods: SensiTest Colistin (Liofilchem, Italy) and MICRONAUT MIC-Strip (MERLIN Diagnostika GmbH, Germany). Data were analyzed by comparison of MIC values and strains susceptibility interpretation criteria (resistant and sensitive, respectively). The same interpretation results were obtained for 46 (93.9%) P. aeruginosa and 37 (75.5%) A. baumannii isolates in all of the applied methods. Using broth microdilution methods, the same interpretation was obtained for 48 (98.0%) P. aeruginosa and 42 (85.7%) A. baumannii isolates. The results obtained by colistin gradient strips usually confirm the results of broth microdilution tests for P. aeruginosa isolates, the automated method is in turn less labor-intensive. However, MIC values, obtained with their use, are less precise because of the antibiotic dilutions limited to only several concentrations. The results underline the importance of choosing of the appropriate type of method, also among those recommended and commercially available.