Acquisition of a High Diversity of Bacteria during the Hajj Pilgrimage, Including Acinetobacter baumannii with blaOXA-72 and Escherichia coli with blaNDM-5 Carbapenemase Genes.

Pilgrims returning from the Hajj (pilgrimage to Mecca) can be carriers of multidrug-resistant bacteria (MDR). Pharyngeal and rectal swab samples were collected from 98 pilgrims before and after they traveled to the Hajj in 2014 to investigate the acquisition of MDR bacteria. The bacterial diversity in pharyngeal swab samples was assessed by culture with selective media. There was a significantly higher diversity of bacteria in samples collected after the return from the Hajj than in those collected before (P = 0.0008). Surprisingly, Acinetobacter baumannii strains were isolated from 16 pharyngeal swab samples (1 sample taken during the Hajj and 15 samples taken upon return) and 26 post-Hajj rectal swab samples, while none were isolated from samples taken before the Hajj. Testing of all samples by real-time PCR targeting blaOXA-51 gave positive results for only 1% of samples taken during the Hajj, 21/90 (23.3%) pharyngeal swab samples taken post-Hajj, and 35/90 (38.9%) rectal swab samples taken post-Hajj. One strain of A. baumannii isolated from the pharynx was resistant to imipenem and harbored a blaOXA-72 carbapenemase gene. Multilocus sequence typing analysis of 43 A. baumannii isolates revealed a huge diversity of 35 sequence types (STs), among which 18 were novel STs reported for the first time in this study. Moreover, we also found one Escherichia coli isolate, collected from a rectal swab sample from a pilgrim taken after the Hajj, which harbored blaNDM-5, blaCTX-M-15, blaTEM-1, and aadA2 (ST2659 and ST181). In conclusion, pilgrims are at a potential risk of acquiring and transmitting MDR Acinetobacter spp. and carbapenemase-producing Gram-negative bacteria during the Hajj season.