Multi-drug resistance, inappropriate initial antibiotic therapy and mortality in Gram-negative severe sepsis and septic shock: a retrospective cohort study

Table 7 Predictors of receiving initially inappropriate antibiotic therapy ^a

	Odds ratio	95% confidence interval	P value
Stenotrophomonas maltophilia	91.981	20.538 to 411.956	<0.001
Multidrug resistant	23.045	12.097 to 43.900	<0.001
Acinetobacter spp.	17.410	9.600 to 31.574	<0.001
HIV	4.547	1.255 to 16.477	0.021
Bacteroides spp.	4.202	2.466 to 7.159	<0.001
Transfer from another hospital	2.280	1.527 to 3.403	<0.001
Polymicrobial	2.294	1.498 to 3.512	<0.001
Prior antibiotics	1.793	1.238 to 2.597	0.002
Congestive heart failure	1.683	1.097 to 2.582	0.017
APACHE II score	1.051	1.023 to 1.081	<0.001

^aThis model includes all factors identified in the model in Table 4 with the addition of the three pathogens with strikingly different initially appropriate antibiotic therapy patterns identified in Table 6. Please note that all other previously identified factors stayed in, except nursing home residence, which fell out based on significance (lower bound of the 95% confidence interval was 0.921). The area under the receiver operating characteristics curve is improved compared with the model in Table 4. However, we feel that this model does not add any clinical or policy utility when compared with the original model. While the multidrug-resistant designation provides an actionable data point with regard to stewardship and prevention of resistance development, the other microbiology variables simply represent organisms routinely isolated from septic patients. For this reason, we are offering this alternate regression and retaining the original regression as a part of the main manuscript. These data further emphasize the need for clinicians to know their individual centers’ case mix vis-à-vis microorganisms associated with sepsis and their predominant susceptibility patterns. APACHE, Acute Physiology and Chronic Health Evaluation. Area under the receiver operating characteristics curve = 0.827, Hosmer–Lemeshow P = 0.162.

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