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Abstract 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.

Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for hard-to-treat infections. The presence of 19 virulence genes in 120 MRSA isolates obtained from hospitalized patients and genetic relationships of these isolates were investigated. The eno (100%) and ebps (93.3%) genes encoding laminin- and elastin binding proteins, respectively, were ubiquitous. Other adhesion genes: fib (77.5%), fnbB (41.6%), bbp (40.8%), cna (30.8%) encoding proteins binding fibrinogen, fibronectin, bone sialoprotein and collagen, respectively, and map/eap (62.5%), encoding Eap, were also frequent. The etB and etD genes, encoding exfoliative toxins, were present in 15.6% and 12.5% isolates, respectively. The splA, splE and sspA, encoding serine protease were detected in 100%, 70.8% and 94.2% isolates, respectively. The tst gene, encoding toxic shock syndrome toxin-1 was found in 75% isolates. The cna, map/eap and tst genes were the most common in wound isolates and much less common in blood isolates. We identified 45 different spa types, t003 (21.7%) and t008 (18.8%) being the most common. The t003 was the most frequent among isolates from the respiratory tract (35.5%), while t008 in blood isolates (40%). Identification of virulence factors of MRSA is important for evaluation of pathogen transmission rate and disease development.