Performance of CarbaNP and CIM tests in OXA-48 carbapenemase-producing Enterobacteriaceae

Carbapenems are the last drugs of choice apart from colistin against serious infections caused by Gram-negative bacteria. However, there are increasing number of reports indicating prevailing emergence of metallo-β-lactamase (MBL)-producing clinical isolates worldwide and among them New Delhi MBL (NDM) is the most prevalent one. This study reports NDM-1 for the first time among Klebsiella pneumoniae from hospitalized patients in Baghdad, Iraq. Fifty-five clinical isolates of K. pneumoniae resistant to carbapenem were investigated from burned wounds, sputum, and blood samples. The susceptibility to different antibiotics was tested by VITEK-2 system. All strains were multidrug-resistant and they showed nine different antimicrobial-resistant patterns (A-I) and the most effective antibiotic on these strains was levofloxacin (85.45%). The phenotypic detection of carbapenemases by MASTDISCS D70C revealed 29 (52.73%) strains were MBL-producing, out of 55 were carbapenem-resistant K. pneumoniae strains. The bla and other MBL genes were detected by conventional PCR and the result showed 37 (67.27%) strains positive for bla gene and only 5 (9.1%) strains harbored bla gene, while all strains were negative for bla, bla, bla, and bla genes. Our results showed the coexistence of both bla and bla genes in three strains of K. pneumoniae, while indicated widespread NDM-1 in Baghdad, Iraq. Hence, it is necessary to follow proper infection control practices and physicians should be aware of the patients with such risk factors.

Section: Discussionmentioning

confidence: 99%

Emergence of NDM-1 among carbapenem-resistant Klebsiella pneumoniae in Iraqi hospitals

Hussein

2017

“…In Istanbul, Turkey, the Ambler class D β-lactamase OXA-48 was initially identified from a carbapenem-resistant isolate of K. pneumoniae. In our country, β-lactamase OXA-48 is the most common carbapenemase, but recently, the association between OXA-48 and NDM-1 has been reported frequently [3,4].…”

Section: Introductionmentioning

confidence: 90%

High rate of colistin and fosfomycin resistance among carbapenemase-producing Enterobacteriaceae in Turkey

Yıldız

Kaşkatepe

Şimşek

et al. 2018

Self Cite

When the problem with carbapenem-resistant Enterobacteriaceae (CRE) increases, the older antimicrobial agents such as colistin and fosfomycin are used for the treatment of these infections. In this study, the broth microdilution method for colistin and the agar dilution method for fosfomycin were used for a total of 147 multidrug-resistant (MDR) or extensively drug-resistant (XDR) strains of CRE. The study included Klebsiella pneumoniae (91.16%), Escherichia coli (7.48%), Enterobacter cloacae (0.68%), and Serratia marcescens (0.68%). All these strains produce various types of carbapenemase, including OXA-48, NDM, and KPC. Some of these strains also have three different carbapenemase mechanisms, including OXA-48 (78.23%), NDM (2.04%), and KPC (0.68%) or OXA-48 and NDM (10.88%), or OXA-48 and KPC (0.68%). About 76.19% of the strains and 67.35% of the strains were resistant for colistin and fosfomycin, respectively. A total of 21 out of 35 colistin-susceptible strains were found to be susceptible to fosfomycin. This study showed that the resistance rates of colistin and fosfomycin are high. The MDR and XDR strains of CRE are spreading in our region and thus a monitoring system for CRE should be followed. Moreover, the applicability of antimicrobial stewardship programs should be increased in all inpatient and outpatient settings.

“…Yıldız et al [22] have conducted phenotypic tests on carbapenemaseproducing strains (OXA-48 and NDM-1) and they found that CarbaNP and carbapenem inactivation method tests were suitable for describing carbapenem producers. In a study, NDM-5 has been shown to increase the MIC values for ceftazidime, cefotaxime, and cefepime comparing with NDM-1 [23].…”

Section: Düzgünmentioning

confidence: 99%

Effect of amino acid substitution in New Delhi metallo-β-lactamase on carbapenem susceptibility

Düzgün

2018

The aim of this work was investigation of clinically important amino acid substitutions of NDM-1 variants. A bla gene was cloned into expression vector pET100/D-TOPO. The sequence of NDM-1 variants with substituted amino acids was determined by ClustalW program. A pET100/D-TOPO + bla was used to generate the alanine mutations at different positions, such as NDM-2 (P28A), NDM-3 (D95A), NDM-4 (M154A), NDM-5 (V88A), NDM-7 (D130A), and NDM-9 (E152A). The mutant variants were transformed into Escherichia coli DH5α. Changes in the activities of alanine mutation variants were determined by E-test. All samples had 32 μg/ml MIC values against ampicillin. The 28 amino acid mutation sample had the highest MIC value against ceftazidime, whereas decreased MIC value for piperacillin. It was observed that the resistance to imipenem was increased in mutant variants D95A, M154A, D130A, and E152A, comparing with P28A and V88A. It was found that NDM-1 has 0.64 μg/ml and the 130 amino acid mutation sample has 0.75 μg/ml meropenem MIC value.