Epidemiology and risk factors for pyogenic liver abscess in the Calgary Health Zone revisited: a population-based study

Table 3 Microbial constituents in PLA between cohorts

Factor	1999–2003 Cohort	2015–2017 Cohort	p value
Polymicrobial	35/71 (49%)	44/136 (32%)	0.01
Nosocomial PLA	6/71 (9%)	6/136 (4.4%)	0.19
Streptococcus anginosus group	31/71	54/136	0.34
Klebsiella species	19/71	34/136	0.45
Anaerobes^a	14/71	22/136	0.32
Escherichia coli	11/71	24/136	0.43
Enterococcus species	5/71	12/136	0.44
Staphylococcus aureus	4/71	2/136	0.11
Other bacteria	11/71	26/136	0.33
Culture negative^b	12/71	13/136	0.10
Antimicrobial resistant isolate present	1/71	11/136	0.04

^aAnaerobes included Clostridium perfringens, Bacteroides species, Peptostreptococcus species, Fusobacterium species, Actinomyces species, Prevotella species, Lactobacillus species, Veillonella species. The prevalence of these organisms was not different between the two cohorts
^bPatients classified as culture negative had negative blood and aspiration cultures (4/136) or negative blood cultures only when aspiration was not performed (9/136)

ISSN: 1471-2334