Prevalence of blaKPC and its occurrence with other beta-lactamases in Klebsiella pneumoniae

Antimicrobial resistance and carbapenemase dissemination in Pseudomonas aeruginosa isolates from Libyan hospitals: a call for surveillance and intervention

Pseudomonas aeruginosa is a multidrug-resistant bacterium capable of forming biofilms. This study aimed to assess resistance of clinical isolates from Libyan hospitals to antipseudomonal antibiotics, the prevalence of selected extended-spectrum β-lactamases and carbapenemase genes among these isolates, and the microorganisms' capacity for alginate and biofilm production. Forty-five isolates were collected from four hospitals in Benghazi and Derna, Libya. Antimicrobial susceptibility was determined using agar disc diffusion. The presence of resistance genes (blaCTXM, blaTEM, blaSHV-1, blaGES-1, blaKPC, and blaNDM) was screened using PCR. Biofilm formation was quantified via the crystal violet assay, while alginate production was measured spectrophotometrically. Resistance to antipseudomonal antibiotics ranged from 48.9% to 75.6%. The most prevalent resistance gene was blaNDM (26.7%), followed by blaGES-1 (17.8%). Moreover, all isolates demonstrated varying degrees of biofilm-forming ability and alginate production. No statistically significant correlation was found between biofilm formation and alginate production. The dissemination of resistant genes in P. aeruginosa, particularly carbapenemases, is of great concern. This issue is compounded by the bacteria's biofilm-forming capability. Urgent intervention and continuous surveillance are imperative to prevent further deterioration and the catastrophic spread of resistance among these formidable bacteria.

Prevalence and clonal relatedness of NDM and OXA-48-producing Klebsiella pneumoniae in a tertiary care hospital in South India

BACKGROUND

Carbapenems are used for the treatment of serious infections caused by multidrug-resistant Klebsiella pneumoniae. Resistance to carbapenems in K. pneumoniae is mainly due to metallo-beta-lactamases (NDM, IMP, and VIM) and class D oxacillinase (OXA-48-like).

AIM AND OBJECTIVE

This study was undertaken to detect the genes encoding for carbapenemase in K. pneumoniae and to determine the clonal relatedness of selected isolates of K. pneumoniae producing NDM and OXA-48 by pulsed-field gel electrophoresis method (PFGE).

MATERIALS AND METHODS

The isolates were collected over a period of 1 year. A total of 370 clinically significant, nonduplicate isolates of K. pneumoniae were included in this study. Phenotypic tests for the detection of carbapenemases were performed for all the isolates. Polymerase chain reaction (PCR) was carried out for the detection of carbapenemase genes such as bla _KPC, bla _IMP, bla _VIM, bla _NDM, and bla _OXA-48. PFGE was performed, and the PFGE profiles were analyzed and compared using BioNumerics version 7.6.

RESULTS

Of the 370 isolates of K. pneumoniae, carbapenemase genes were detected in 13.78% (51/370). bla _OXA-48 was the prevalent gene detected followed by bla _NDM and bla _KPC. Thirty strains of K. pneumoniae selected by PFGE analysis were divided into five clusters (A, B, C, D, and E). Cluster C was the major type detected carrying bla _NDM and bla _OXA-48 genes.

CONCLUSION

bla _OXA-48 was the most prevalent gene detected in this study. PCR is useful in detecting carbapenemase genes, especially bla _NDM, which may show false susceptibility to carbapenems. There was no direct correlation detected between PFGE profiles and antibiotic susceptibility pattern. PFGE has revealed the genomic diversity among isolates, thereby suggesting heterogeneity in strain circulation within intensive care unit and wards of the hospital. Monitoring and molecular typing is essential to curtail the spread of multidrug-resistant strains and control the outbreaks of infection.