Emergence of New Delhi Metallo-Beta-Lactamase (NDM) and Klebsiella pneumoniae Carbapenemase (KPC) Production by Escherichia coli and Klebsiella pneumoniae in Southern Vietnam and Appropriate Methods of Detection: A Cross-Sectional Study.

Cuong Q Hoang,Lan T Phan,Hai D Nguyen,Tuyet S M Nguyen,Trung L Tran,Hang T T Tran,Binh T Pham,Anh T Nguyen,Huy Q Vu,Y M Dao,Dung A Nguyen,Hanh T H Nguyen

doi:10.1155/2019/9757625

Abstract

Carbapenemase-producing Enterobacteriaceae (CPE) are well known to cause many serious infections resulting in increasing mortality rate, treatment cost, and prolonged hospitalization. Among the widely recognized types of carbapenemases, New Delhi β-lactamase (NDM) and Klebsiella pneumoniae carbapenemase (KPC) are the most important enzymes. However, in Vietnam, there are only scattered reports of CPE due to the lack of simple and affordable methods that are suitable to laboratory conditions. This study aims to survey the characteristics of carbapenem-resistant E. coli and K. pneumoniae (CR-E/K) at two hospitals in Southern Vietnam and perform some simple methods to detect the two enzymes. A total of 100 CR-E/K strains were collected from clinical isolates of Gia Dinh People's Hospital and Dong Nai General Hospital, Vietnam, from November 2017 to May 2018. The patient-related information was also included in the analysis. We conducted real-time polymerase chain reaction (PCR), Modified Hodge Test (MHT), and combined disk test (CDT) on all isolates. Carbapenemase-encoding genes were detected in 47 isolates (36 NDM, 10 KPC, and one isolate harboring both genes). The E. coli strain carrying simultaneously these two genes was the first case reported here. Most of isolates were collected from patients in ICU, Infectious Disease Department, and Department of Urologic Surgery. Urine and sputum were two common specimens. The true positive rate (sensitivity, TPR) and specificity (SPC) of the imipenem–EDTA (ethylen diamine tetra acetic acid) for NDM detection and the imipenem–PBA (phenylboronic acid) for KPC detection on E. coli were 93.8%, 97.1% and 66.7%, 95.7%, respectively. Meanwhile, the imipenem–EDTA for NDM detection and the imipenem–PBA for KPC detection among K. pneumonia achieved 90.5%, 100% and 100%, 92.9% TPR and SPC, respectively. However, MHT showed low sensitivity and specificity. Our findings showed that CP-E/K were detected with high prevalence in the two hospitals. We suggest that CDT can be used as a low-priced and accurate method of detection.

Highlights

Antibiotic resistance is a tremendous health problem
These two genes harboring bacteria were more dangerous and resistant to carbapenem with a higher level than bacteria that harbored other types of carbapenemase-encoding genes [6, 16,17,18]. These carbapenemaseproducing bacteria result in severe infections with high mortality rate; the infection caused by Klebsiella pneumoniae carbapenemase (KPC)-producing K. pnuemoniae was from 40% to 56% [16] and up to 88% for New Delhi β-lactamase (NDM)-1 producing Enterobacteriaceae [6]
Of 100 strains from clinical samples (50 isolates of E. coli and 50 isolates of K. pneumoniae), 47 isolates were positive by real-time polymerase chain reaction (PCR)

Summary

Introduction

Antibiotic resistance is a tremendous health problem. This includes the resistance to carbapenems which was considered as the last resort for Enterobacteriaceae infections [1]. E. coli and K. pneumoniae are the most common pathogens in Enterobacteriaceae family These carbapenemasae-producing bacteria were found in many countries, such as China [3], Parkistan [4], India [5], Turkey [6], Brazil [7], Mexico [8], Peru [9], and Greece [10]. These two genes harboring bacteria were more dangerous and resistant to carbapenem with a higher level than bacteria that harbored other types of carbapenemase-encoding genes (including OXA48-like, another popular carbapenemase present in Enterobacteriaceae) [6, 16,17,18] These carbapenemaseproducing bacteria result in severe infections with high mortality rate; the infection caused by KPC-producing K. pnuemoniae was from 40% to 56% [16] and up to 88% for NDM-1 producing Enterobacteriaceae [6]. Carbapenem minimum inhibitory concentrations (MICs) for these two types of carbapeenemase producers in recent studies were higher than carbapenem MIC values against OXA-48 type producers [17, 18]

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