NDM-1 cases and outbreaks in Turkey

Abstract

We are grateful to Hatipoğlu and Turhan [Mikrobiyol Bul 2014; 48(1): 188-9] for their interest in our study published in Mikrobiyol Bul 2013; 47(2): 382-4. As Hatipoğlu and Turhan mentioned in their comment, ertapenem is more sensitive than other carbapenem antibiotics for the identification of New Delhi Metallo-beta-lactamase (NDM-1) producers among carbapenem-resistant strains being studied. However, its low specificity [Dortet et al. Biomed Res Int 2014; 2014: 249856] makes it equal with other carbepenems. Since all the isolates in our study were not tested for ertapenem susceptibility, we used the susceptibility data for three carbapenems to increase the sensitivity of our study regarding isolate selection. We agree Hatipoğlu and Turhan about the Modified Hodge Test (MHT) and we did not use MHT at all in our study. However we couldn’t understand how they came to a conclusion that we used MHT and didn’t mention in Material and Methods section. ZnSO4 supplemented MHT which was recommended by the authors [Dortet et al. Biomed Res Int 2014; 2014: 249856] has a sensitivity rate of about 85%. Thus we used molecular methods instead of MHT not to miss any single isolate. Hatipoğlu and Turhan mentioned about previously reported four NDM-1 positive isolates without any international relation in Turkey. However, since this mentioned study [Alp et al. J Hosp Infect 2013; 84(2): 178-80] was published after the appeal, acceptance and publication of our study, eventually we didn’t have the opportunity to discuss the data of Alp’s report. In the same study authors stated that NDM-1 producing isolates were isolated from pediatric patients and had no connection with patients from Indian peninsula. At the same time Poirel et al. [Antimicrob Agents Chemother 2014; 58(5): 2929-33] reported in their study that NDM-1 producing isolates from pediatric patients had clonal relation with Enterobacter cloacae strains and subject to an outbreak. The evaluation of the previous reports about NDM-1 indicated that NDM-1 was initially originated from foreign sources before exhibit- ing endemicity in a country. Thus the situation in our region was not an exception. In conclusion, medical facilities taking care of foreign patients should pay particular attention to identification of NDM-1 isolates and establishment of appropriate control measures.