Multidrug-resistant Klebsiella pneumoniae harboring extended spectrum β-lactamase encoding genes isolated from human septicemias

Abstract

Klebsiella pneumoniae is a major pathogen implicated in nosocomial infections. Extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae isolates are a public health concern. We aim to characterize the type of β-lactamases and the associated resistance mechanisms in ESBL-producing K. pneumoniae isolates obtained from blood cultures in a Portuguese hospital, as well as to determine the circulating clones. Twenty-two cefotaxime/ceftazidime-resistant (CTX/CAZR) K. pneumoniae isolates were included in the study. Identification was performed by MALDI-TOF MS and the antimicrobial susceptibility testing by disk-diffusion. The screening test for ESBL-production was performed and ESBL-producer isolates were further characterized. The presence of different beta-lactamase genes (blaCTX-M, blaSHV, blaTEM, blaKPC, blaNDM, blaVIM, blaOXA-48, blaCMY-2, blaDHA-1, blaFOX, blaMOX, and blaACC) was analyzed by PCR/sequencing in ESBL-producer isolates, as well as the presence of other resistance genes (aac(6’)-Ib-cr, tetA/B, dfrA, qnrA/B/S, sul1/2/3) or integron-related genes (int1/2/3). Multilocus-sequence-typing (MLST) was performed for selected isolates. ESBL activity was detected in 12 of the 22 CTX/CAZR K. pneumoniae isolates and 11 of them carried the blaCTX-M-15 gene (together with blaTEM), and the remaining isolate carried the blaSHV-106 gene. All the blaCTX-M-15 harboring isolates also contained a blaSHV gene (blaSHV-1, blaSHV-11 or blaSHV-27 variants). Both blaSHV-27 and blaSHV-106 genes correspond to ESBL-variants. Two of the CTX-M-15 producing isolates carried a carbapenemase gene (blaKPC2/3 and blaOXA-48) and showed imipenem resistance. The majority of the ESBL-producing isolates carried the int1 gene, as well as sulphonamide-resistance genes (sul2 and/or sul3); the tetA gene was detected in all eight tetracycline-resistant isolates. Three different genetic lineages were found in selected isolates: ST348 (one CTX-M-15/TEM/SHV-27/KPC-2/3-producer isolate), ST11 (two CTX-M-15/TEM/SHV-1- and CTX-M-15-TEM-SHV-11-OXA-48-producer isolates) and ST15 (one SHV-106/TEM-producer isolate). ESBL enzymes of CTX-M-15 or SHV-type are detected among blood K. pneumoniae isolates, in some cases in association with carbapenemases of KPC or OXA-48 type.

Characterization of ESBL-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Clinical Samples in a Northern Portuguese Hospital: Predominance of CTX-M-15 and High Genetic Diversity

“…In addition, Klebsiella pneumoniae can be found in the intestinal microbiota of healthy humans and animals although may also cause life-threatening infections; it is considered a major opportunistic pathogen implicated in nosocomial infections (as is the case of pneumonia or bloodstream infections), especially in patients of intensive-care units (UCIs) and in immunocompromised hosts with severe underlying diseases. K. pneumoniae strains can accumulate resistance genes, increasing their pathogenicity and causing severe infections [ 1 , 3 , 4 , 5 ]. Moreover, it is known that K. pneumoniae spreads easily, mainly in the hospital environment [ 5 ].…”

“…K. pneumoniae strains can accumulate resistance genes, increasing their pathogenicity and causing severe infections [ 1 , 3 , 4 , 5 ]. Moreover, it is known that K. pneumoniae spreads easily, mainly in the hospital environment [ 5 ].…”

“…In particular, ESBLs of CTX-M-type and qAmpC enzymes (especially the CMY-2 type) were increasingly reported worldwide, specifically among clinical isolates from E. coli [ 7 , 8 , 9 ] and K. pneumoniae [ 6 , 10 , 11 , 12 ]. Moreover, recent studies reported ESBL-producing K. pneumoniae isolates among urinary tract infections and invasive infections in patients in Portugal [ 4 , 5 , 9 ], as well as among healthy Portuguese students in Lisbon [ 13 ]. Furthermore, a previous report created by our group showed the presence of ESBL-producing E. coli among healthy and sick cats [ 14 ] and dogs [ 15 ] in Portugal.…”

“…To our knowledge, some studies have been performed in Portugal based on the detection of ESBL-producing Enterobacteriaceae in hospitalized patients [ 3 , 4 , 12 , 19 , 32 , 33 , 34 , 35 , 36 ]. In a previous study performed by our research group, the ESBLs types were determined among invasive K. pneumoniae isolates recovered from blood cultures in a hospital located in Northern Portugal [ 5 ]. The purpose of the present study is to expand this previous work by analyzing in the same hospital the ESBLs types and the main associated resistance mechanisms in broad-spectrum cephalosporin-resistant K. pneumoniae isolates obtained from different clinical origins (except blood), and also in Escherichia coli isolates obtained from blood and urine samples; furthermore, the genetic lineages of selected isolates were also the aim of this research.…”

Investigation of the Antibacterial Activity and Efflux Pump Inhibitory Effect of Cycas thouarsii R.Br. Extract against Klebsiella pneumoniae Clinical Isolates

“…Recently, multidrug resistance is highly disseminated among Klebsiella pneumoniae isolates causing serious problems at the clinical sites due to the decreased therapeutic options available to treat such resistant bacteria [ 3 ]. K. pneumoniae isolates could acquire different mechanisms that lead to antibiotic resistance to many antibiotics [ 4 ]. This concern has resulted in high mortality rates and extended hospitalization periods in patients infected with this pathogen [ 5 ].…”