Detection of CTX-M-type extended-spectrum beta-lactamases among Jordanian clinical isolates of Enterobacteriaceae

Cefixime and cefixime-clavulanate for screening and confirmation of extended-spectrum beta-lactamases in Escherichia coli

Introduction

Detection of Extended-Spectrum Beta-Lactamases (ESBLs) depends on screening for resistance to certain cephalosporins, confirmation with selective ESBL inhibitors, and ESBL genes detection. New tests are required for accurate ESBL detection.

Aims

To test the ability of cefixime (CFM) and cefixime-amoxicillin/clavulanate (CFM-AMC) as a screening and confirmatory test for ESBL identification.

Methods

246 clinical isolates of Escherichia coli were tested by an ESBL screening test, a double-disk synergy test (DDST), a disk replacement test, the Vitek 2 ESBL test, and an ESBL genes test by PCR. CFM ESBL Screening was performed by disk diffusion, while CFM-AMC confirmation was performed by DDST and a disk replacement test.

Results

246 E. coli clinical isolates from two referral hospitals were collected over 2 years. The mean age ± standard deviation of patients was 43.8 ± 27.7 years and 76.8% were females. Resistance rates to penicillins, first, second, and third generation cephalosporins, and monobactams were very high at 97%, 84%, 100% and 97%, respectively. ESBL screening was positive in 81.3% of isolates, DDST was positive in 74.8%, disk replacement was positive in 79%, Vitek 2 ESBL test was positive in 67.3%, and ESBL genes were detected in 85.8% of isolates (CTX-M 75%, TEM 42.5%, SHV 4.6%). Compared to genotyping, screening with CFM achieved 87.7% sensitivity and 64.7% specificity. CFM-AMC DDST achieved 75.8% sensitivity and 75.4% specificity, and CFM-AMC disk replacement had 73% sensitivity and 70% specificity.

Conclusions

High prevalence of ESBLs was noted among E. coli isolates, dominated by CTX-M genotype. ESBL screening and confirmation using CFM and CFM-AMC is a new and accurate method for ESBLs detection.

Epidemiology of common resistant bacterial pathogens in the countries of the Arab League

No uniformly organised collection of data regarding antimicrobial resistance has occurred in the countries of the Arab League. 19 countries of the Arab League have published data for antimicrobial susceptibility for the WHO priority organisms, and seven of 14 of these organisms are included in this Review (Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella spp, Staphylococcus aureus, and Streptococcus pneumoniae). Although E coli and Klebsiella spp resistance to third-generation cephalosporins is common in all countries, with prevalence reaching more than 50% in Egypt and Syria, carbapenem resistance is emerging, albeit with a prevalence of less than 10%. Conversely, a large amount of carbapenem resistance has been reported for P aeruginosa and A baumannii across the Arab League, reaching 50% and 88% of isolates in some countries. As for Salmonella spp, the prevalence of fluoroquinolone resistance has exceeded 30% in several areas. With regards to the Gram-positive pathogens, the prevalence of meticillin resistance in S aureus is reported to be between 20% and 30% in most countries, but exceeds 60% in Egypt and Iraq. The prevalence of penicillin non-susceptibility among pneumococci has reached more than 20% in Algeria, Egypt, Morocco, Saudi Arabia, and Tunisia. These findings highlight the need for structured national plans in the region to target infection prevention and antimicrobial stewardship.

Molecular Characterization of Multidrug Resistant Uropathogenic E. Coli Isolates from Jordanian Patients

Background

Emergence of multi-drug resistant uropathogenic E. coli strains is an increasing problem to empirical treatment of urinary tract infections in many countries. This study investigated the magnitude of this problem in Jordan.

Methods

A total of 262 E. coli isolates were recovered from urine samples of Jordanian patients which were suspected to have urinary tract infections (UTIs). All isolates were primarily identified by routine biochemical tests and tested for antimicrobial susceptibility by disc diffusion method. Fifty representative Multidrug Resistance (MDR) E. coli isolates to 3 or more antibiotic classes were tested for the presence of resistance genes of blaCTX-M- 1, 9 and 15, carbapenemase (blaIMP, blaVIM, blaNDM-1, blaOXA-48), fluoroquinolones mutated genes (parC and gyrA) and clone of ST131 type using PCR methods.

Results

A total of 150/262 (57.3%) of E. coli isolates were MDR. Urine samples of hospitalized patients showed significantly more MDR isolates than outpatients. Fifty representative MDR E. coli isolates indicated the following molecular characteristics: All were positive for mutated parC gene and gyrA and for ST131 clone, and 78% were positive for genes of CTX-M-15, 76% for CTX-M-I and for 8% CTX-M-9, respectively. Additionally, all 50 MDR E. coli isolates were negative for carbapenemase genes (blaIMP, blaVIM, blaNDM-1, blaOXA-48), except of one isolate was positive for blaKPC-2 .

Conclusion

This study indicates alarming high rates recovery of MDR uropathogenic E. coli from Jordanian patients associated with high rates of positive ST131 clone, fluoroquinolone resistant and important types of blaCTX-M.

Detection of OXA-48-like and NDM carbapenemases producing Klebsiella pneumoniae in Jordan: A pilot study

Little is known of carbapenemase producing Klebsiella pneumoniae (CPK) in Jordan. This study aimed to determine the prevalence of CPK in a major hospital in Amman, Jordan in 2012-2013 and to characterize the isolates and detect the types of carbapenemase(s) they produced. For the 296 isolates investigated, species identification and antimicrobial susceptibilities were determined (Vitek II, bioMérieux). Isolates with decreased ertapenem susceptibility were tested for carbapenemase production using the Modified Hodge Test. Isolates with a carbapenemase-positive phenotype were characterized further via multiplex PCRs for extended-spectrum β-lactamase and carbapenemase genes and by Pulsed Field Gel Electrophoresis (PFGE). Seven of 296 K. pneumoniae isolated in 2012-2013 (2.4%) were carbapenemase producers, five produced class D carbapenemases (OXA-48-like) and two produced a NDM metallo-beta-lactamase. All seven isolates also encoded CTX-M enzymes; CTX-M-1-like enzymes were detected in five isolates (two co-producing NDM enzymes and three co-producing OXA-48-like enzymes), CTX-M-9 was found in the two remaining OXA-48-like producers. PFGE revealed five genetically distinct types amongst the seven carbapenemase producing K. pneumoniae, with two pairs of identical isolates associated with patients treated on the same wards. The emergence of OXA-48-like and NDM carbapenemases associated with multi-drug resistant (MDR) isolates in Jordan is concerning. The strict implementation of infection control practices will help to disrupt the spread of MDR carbapenemase producers in Jordanian hospitals.