Fecal carriage of MDROs in a population of Lebanese elderly: Dynamics and impact on bacterial fitness

Abstract

Muti-Drug Resistant Organisms (MDROs) are problematic all over the world, especially in Lebanon. High fecal carriage rates of MDR Enterobacteriaceae were reported from Lebanese nursing homes. Some studies show that MDROs have a fitness cost as compared to sensitive isolates. In this study, the competitive growth of MDR Escherichia coli obtained from fecal samples from elderly is assessed. Fecal swabs from ten elderly patients from a Lebanese nursing home were obtained between June and December, 2015. Isolates were identified by API 20E and antimicrobial susceptibilities were determined. Production of ESBL (extended spectrum β lactamase), MBL (metallo β lactamse), AmpC and KPC (Klebsiella pneumonia carbapenemase) was detected phenotypically by the use of EDTA, PBA, cloxacillin, and DDSTs. In-vitro competition assays were performed using E. coli isolates with different combinations of bacterial resistance. A total of 117 isolates was obtained with 71.8% E. coli, 7.7% of which were ESBL and 5.1% AmpC producers. Sensitive E. coli isolates out-competed all other isolates when in competition, followed sequentially by ESBL, AmpC, and OXA-48 (oxacillin) producers. This study shows an advantage of sensitive E. coli strains obtained from fecal samples to out-compete resistant strains in specific in-vitro conditions. This ability could be exploited in the elimination of MDR organisms from the gut flora, after further investigation.

The Effect of Infection Precautions on Extended-Spectrum Beta-Lactamase Enterobacteriaceae Colonization Among Nurses in Three Beirut Hospitals

“…The comparable prevalence between clinical samples from this study, and the prevalence among nursing staff of hospitals without CP would indirectly support the idea that hospital CP practices impart at least some protection against MDRO colonization. We find a similarity between the prevalence data of the hospital still requiring CP to that of a Lebanese nursing home data [55], which is lower than the hospital resistance data described above [54]. This is likely due to the nursing home prevalence being more reflective of community prevalence data as opposed to acute-care hospital data.…”

“…Interestingly, a study by Challita et al in 2015 demonstrated an ESBL E. coli prevalence of 7.7% in a Lebanese nursing home [55]. We are not able to explain this lower-than-average prevalence data point, especially in a cohort of institutionalized elderly patients.…”

“…However, we do find a reflection of this prevalence in our nursing staff cohort at Hospital 1, where CP continues to be practiced. Hence, we question whether the effect of healthcare acquisition is mitigated by strict adherence to CP, ultimately resulting in a lower prevalence of ESBL colonization among nurses, with 8.9% ESBL positive carriers in Hospital 1, comparable to the 7.7% ESBL E. coli in the Challita study [55].…”