Carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPAE) are globally a major medical issue, especially in intensive care units. The digestive tract is the main reservoir for these isolates; therefore, rectal swab surveillance is highly recommended. The purpose of this study was to detect the prevalence of gastrointestinal tract colonization of CRE and CRPAE in patients admitted to intensive care units in Saudi Arabia. This project also aimed to characterize carbapenem-hydrolyzing enzyme production in these isolates. From February to May 2015, 200 rectal swab specimens were screened by CHROMagar KPC. Organism identification and susceptibility testing were performed using the Vitek 2 system. One CRE and 13 CRPAE strains were identified, for a prevalence of 0.5% (1/200) and 6.5% (13/200) respectively. Strains showed high genetic diversity using enterobacterial repetitive intergenic consensus sequence-based PCR. NDM type and VIM type were detected by PCR in four and one CRPAE isolates respectively. ampC overexpression was detected in eight CRPAE isolates using Mueller-Hinton agar containing 1000 μg/mL cloxacillin. CTX-M-15 type was detected in 1 CRE by PCR. The prevalence of CRE strain colonization was lower than that of CRPAE isolates. The detection of NDM and VIM in the colonizing CRPAE strains is a major infection control concern. To our knowledge, this is the first study in Saudi Arabia and the gulf region focusing on digestive tract colonization of CRE and CRPAE organisms and characterizing the mechanisms of carbapenem resistance.

Objectives:To detect resistance genes to fluoroquinolones and β-lactams in Salmonella strains from a Saudi hospital.Methods:From October 2015 to December 2016, a total of 149 Salmonella strains were collected from stool specimens from patients admitted to King Fahad Hospital of the University, AlKhobar, Saudi Arabia using CHROMagar Salmonella. The organism identification and antimicrobial susceptibility testing were performed using Vitek 2 system. Strain serogrouping was performed using Wellcolex color Salmonella kit. Fluoroquinolone resistance genes, extended-spectrum β-lactamases (ESBLs), and AmpC β-lactamase were determined using polymerase chain reaction (PCR). Enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) was used to determine clonal relatedness.Results:The resistance rates to cefotaxime were 1.3% and ciprofloxacin 19.5%. Plasmid mediated quinolone resistance (PMQR) genes, qnrB and qnrS, were detected in 8 strains, qnrB (n=5) and qnrS (n=3), respectively. No ESBLs, AmpC, or mutations in the topoisomerases were detected. Salmonella isolates formed 7 clusters with similarity.Conclusions:This study reveals the emergence of fluoroquinolone resistant Salmonella in the region imposing public health concerns.