High proportions of multidrug-resistant Klebsiella pneumoniae isolates in community-acquired infections, Brazil

Abstract

Klebsiella pneumoniae is one of the leading causes of bloodstream (BSI) and urinary tract infections (UTI), but limited data is available regarding community-acquired (CA) infections. This study characterized the clinical aspects of CA-BSI and CA-UTI caused by K. pneumoniae and the molecular features of isolates, including their resistance profiles. Sixty-five isolates (CA-BSI, n = 24; CA-UTI, n = 41) underwent antimicrobial susceptibility testing, β-lactamase and virulence gene assessment, capsular genotyping, and molecular typing. Older age, male gender, and comorbidities, particularly kidney disease, were significantly associated with CA-BSI. The MDR and carbapenem resistance rates for K. pneumoniae from CA infections were 24.6% and 4.6%, respectively. CA-BSI isolates were more antibiotic-resistant and had a higher proportion of ESBL-producing (37.5% versus 9.8%) and MDR isolates (45.8% versus 12.2%) than CA-UTI. The bla_CTX-M-like or bla_KPC-like genes was found in all ESBL-producing isolates, while bla_KPC-like and bla_NDM-like were detected exclusively in CA-BSI strains. The isolates' virulence profiles were similar between the groups, although one CA-BSI and two CA-UTI isolates presented hypervirulence biomarkers. A high clonal diversity was observed, with a majority of MDR (81.3%) (ST11, ST15, ST101, ST258, ST307, and ST6852) and hypervirulent (2/3) (ST23 and ST65) isolates being high-risk pandemic clones in humans. Our data highlight the high prevalence of MDR K. pneumoniae in CA infections in Brazil, with CA-BSI showing significant differences in resistance profiles compared to CA-UTI.

Keywords: Klebsiella pneumoniae; Antimicrobial resistance; Bloodstream infections; Community-acquired; High-risk clones; Urinary tract infections.

Fig. 1

Molecular profile of Klebsiella pneumoniae from community-acquired bloodstream infections and community-acquired urinary tract infections (n = 65). AK, amikacin; AMC, amoxicillin-clavulanic acid; ATM, aztreonam; CAZ, ceftazidime; CFO, cefoxitin; CIP, Ciprofloxacin; COL, colistin; CRO, ceftriaxone; FEP, cefepime; GEN, gentamicin; hvKp, hypervirulent Klebsiella pneumoniae; IMP, imipenem; LVX, levofloxacin; MDR, multidrug-resistant; MEM, meropenem; NIT, nitrofurantoin; ST, sequence typing; SXT, trimethoprim-sulfamethoxazole; TOB, tobramycin; TZP, piperacillin-tazobactam. *New ST; **New wzi alleles.

Fig. 2

Frequency of antimicrobial resistance of Klebsiella pneumoniae from community-acquired bloodstream infections (n = 24) and community-acquired urinary tract infections (n = 41). BSI, bloodstream infection; CA, community-acquired; ESBL, extended-spectrum β-lactamase; MDR, multidrug resistance; UTI, urinary tract infection.

Fig. 3

Frequency of β-lactamases genes in Klebsiella pneumoniae from community-acquired bloodstream infections (n = 24) and community-acquired urinary tract infections (n = 41). BSI, bloodstream infection; CA, community-acquired; UTI, urinary tract infection.

Fig. 4

goeBURST-based population structure of 43 STs from 59 Klebsiella pneumoniae isolates. Five distinct clusters (C-1 to C-5) were identified, while 31 STs were singletons. The analysis displays only single-locus variants in a population snapshot. Connections between STs are represented by black lines, and the size of each node is proportional to the number of isolates corresponding to that ST in this study. Group founders are shown in light green, and common nodes are shown in blue. Legend: C, cluster; ST, sequence type.