High-risk clones and novel sequence type ST4497 of Klebsiella pneumoniae clinical isolates producing different alleles of NDM-type and other carbapenemases from a single tertiary-care centre in Egypt.

Enterobacteria producing NDM carbapenemases represent a severe diagnostic and therapeutic challenge in healthcare settings. Infections caused by NDM-positive strains are usually associated with high mortality rates and very limited treatment options. A total number of 33 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates were included in this study, comprising 30 recovered from clinical diagnostic samples and 3 cultured from screening rectal swabs taken at patient admission. Bacterial identification was performed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS) and antibiotic susceptibility testing was performed by reference broth microdilution and a commercial automated method. Isolates were investigated for carbapenemase production using the ß-CARBA test, the modified carbapenem inactivation method (mCIM) and, for the 30 clinical isolates, by MALDI-TOF/MS, using the MBT STARⓇ-Carba IVD Kit. Carbapenem resistance genes were characterised by PCR and sequencing. Seven different blaNDM gene variants were identified in 94% of the isolates, whilst three variants of blaOXA-48-like were detected in 27% of the isolates. Most CRKP corresponded to high-risk clones (ST147, ST11 and ST15). Novel ST4497 is reported for the first time in this study as well as the first emergence of K. pneumoniae ST231 producing OXA-232 in Egypt. These results indicate an ongoing evolution of the blaNDM genes in our area and confirm the need for a maintained surveillance system in order to monitor the spread of these mobile blaNDM genes.

Carbapenem-resistant Klebsiella pneumoniae isolates from Egypt containing blaNDM-1 on IncR plasmids and its association with rmtF.

OBJECTIVES: The aim of this study was to characterize carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates recovered from clinical specimens at a tertiary care hospital in Egypt over a period of 15 months. METHODS: Eight CRKP isolates were included in this study. The minimum inhibitory concentrations of different antibiotics were determined by broth microdilution and Etest methods. Multilocus sequence typing was performed. Antibiotic resistance genes were assessed by PCR and DNA sequencing. Plasmid analysis was done by S1 nuclease digestion of whole genomic DNA followed by pulsed-field gel electrophoresis (S1-PFGE). RESULT: Eight carbapenem-resistant NDM-1-producing K. pneumoniae isolates of three different sequence types (ST) were identified (ST147, ST11, and ST17), in which blaNDM-1 was carried by either IncR or untypeable plasmids. Seven out of the eight isolates also contained the rmtF methylase gene. CONCLUSION: This study describes the occurrence of IncR plasmids carrying blaNDM-1 and rmtF in Egypt, raising concerns regarding this type of replicon and its role in the transmission of these resistance determinants.

CTX-M-15-producing Escherichia coli clinical isolates in Cairo (Egypt), including isolates of clonal complex ST10 and clones ST131, ST73, and ST405 in both community and hospital settings.

In Egypt, little is known about the genetic background of Escherichia coli isolates harboring extended-spectrum ß-lactamase (ESBL). Five hundred twenty Enterobacteriaceae were prospectively collected (May 2007-August 2008) at the Theodor Bilharz Research Institute (Cairo). Among the collected Enterobacteriaceae, 56% (n=291) were E. coli and 32% (n=165) Klebsiella pneumoniae. A total of 16% (n=3) of all isolates were ESBL, 19% (n=55) of the E. coli and 14% (n=23) of the K. pneumoniae. The proportion of E. coli ESBL producers did not differ significantly between in and outpatients (20% vs. 17%) but was significantly different for non-E. coli ESBL producers (18.5% vs. 1.2%: p=0.0001). The majority of E. coli ESBL producers (75%) was isolated from urine. All the ESBL-producing Enterobacteriaceae available for molecular study (n=74) produced CTX-M-15. Among the CTX-M-15-producing E. coli isolates; 40% belonged to phylogenetic group A, 32% to D, and 26% to B2. ERIC-2 PCR profiles were obtained for all these E. coli isolates and multilocus sequence typing for those belonging to group B2. Genotyping analyses showed strain diversity; however, some clusters had profiles indistinguishable from that of previously published clones. Multilocus sequence typing showed that 75% of E. coli group B2 belonged to clone ST131. This indicates that a new country in Africa is adversely affected by clones of E. coli-producing CTX-M-15.