Multidrug Resistant Pseudomonas aeruginosa (MDR-PSA) in USA Hospitals by Geographic Region in 2015

Background: We examined the prevalence of MDR-PSA in hospitalized patients across different USA geographic regions.

Methods: Utilizing a 2015 electronic research dataset established by Becton Dickinson & Company from 346 USA hospitals, non-duplicate PSA isolates (first isolate of a species per 30 day period) from all sources were identified as MDR if intermediate/resistant, as defined by NHSN, to > 1 antibiotic in 3 of the 5 drug classes: ceftazidime or cefepime; ciprofloxacin or levofloxacin; aminoglycosides, carbapenems; and piperacillin/tazobactam. Isolates were categorized as either: admission (< 3 days of an inpatient admission and no previous admission within 14 days) or hospital-onset (>3 days post-admission or within 14 days of discharge). Geographic regions were classified into NHSN categories (Sievert, 2013, ICHE), with Region 1, 7, and 8 being grouped into “other” due to small number of hospitals. We conducted pairwise comparison between regions using the region with the lowest MDR-PSA rate as the reference group.

Results: The overall MDR-PSA rate was 16.1% (7,218/44,844) with admission and hospital-onset settings rates of 13.1% (2,474/18,820) vs 18.2% (4,744/26,024), respectively (P<0.0001). Significant regional differences were noted within admission and hospital-onset settings compared to Region 10 in both settings (see Table).

Region	States	# of Hospitals	MDR-PSA Rate (%)
			Admission	Hospital-Onset
2	NJ, NY, PR, VI	30	13.5*	21.9*
6	AR, LA, NM, OK, TX	59	15.0*	19.7*
9	AZ, CA, HI, Pacific Islands	28	13.0	19.0*
5	IL, IN, MI, MN, OH, WI	85	13.9*	17.2*
4	AL, FL, GA, KY, MS, NC, SC, TN	98	12.7	18.2*
1, 7, 8	All Other	11	11.1	16.7*
3	DE, DC, MD, PA, VA, WV	13	9.6	12.0
10	AK, ID, OR, WA	22	9.0	10.6
Overall		346	13.1	18.2

* P < 0.05 compared to Region 10 within admission & hospital-onset settings

Conclusion: The overall MDR-PSA rate was significantly higher for the hospital-onset setting in the US hospitals, with 1 in 6 PSA isolates being MDR positive. There is a significant regional difference in MDR-PSA rates. Hospitals in different geographic regions need to be aware of their local microbiological epidemiology for MDR-PSA in selecting empiric antibiotics for patients at risk of infection with PSA.