High frequency of NDM-1 and OXA-48 carbapenemase genes among Klebsiella pneumoniae isolates in central Iran

Background The emergence and distribution of multidrug-resistant (MDR) and carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a global health threat.

Therefore, this study aimed to investigate the frequency and antibiotic resistance patterns of MDR, extensively drug-resistant (XDR), and CRKP, as well as the antibiotic resistance genes of Klebsiella pneumoniae ( K. pneumoniae ) isolates from patients’ infectious samples from central Iran.

Methods This study examined 546 clinical samples of patients to identify K. pneumoniae.

The isolates were investigated for their antibiotic resistance profile, extended-spectrum β-lactamase (ESBL), AMPC β-lactamase, carbapenemase resistance, sulfonamide, tetracycline, plasmid-mediated quinolone resistance (PMQR) along with their resistance genes, integrase, and quaternary ammonium compounds ( qac ) by polymerase chain reaction (PCR).

Results Out of 546 clinical samples, 121 (22.1%) cases of K. pneumoniae were identified using culture and PCR methods.

The highest antibiotic resistance rates were found for ampicillin (119/121; 98.3%), cotrimoxazole (78/121; 64.4%), and cefixime, cefotaxime, ceftriaxone, and ceftazidime as a group (77/121; 63.6%).

Tigecycline, colistin, and fosfomycin were the most effective antimicrobial agents with 98.4%, 96.7%, and 95.9% susceptibility, respectively.

The amount of CRKP was 51 (42.1%).

All CRKP isolates were MDR.

The most abundant genes were bla _TEM (77/77; 100%), bla _CTX−M1 (76/77; 98.7%), bla _SHV (76/77; 98.7%), bla _CTX−M15 (73/77; 94.8%) for ESBL; bla _CIT 28 (48.3%) and bla _CMY−2 26 (44.8%) for AMPC β-lactamase; and bla _OXA−48 46 (90.1%) and bla _NDM 36 (70.5%) for carbapenemase.

Among the PMQR determinants, qnrB (25/52; 48%), qnrS (19/52; 36.5%), and qnrA (11/52; 21.1%) were positive from the isolates.

TetA and tetB were recognized in 25 (44.6%) and 17 (30.3%) isolates, respectively.

Class 1 and 2 integrons were recognized in 97 (80.1%) and 53 (43.8%) isolates, respectively.

Conclusions Due to the high prevalence of MDR and CRKP in central Iran, tracking and immediate intervention are necessary for control and inhibition of K. pneumoniae resistant isolates.

Tigecycline, colistin, and fosfomycin are the best treatment options for treatment of patients with CRKP in this geographical area.