Empirical treatment of community-acquired pneumonia and the development of fluoroquinolone-resistant tuberculosis.
BACKGROUND" Fluoroquinolone (FLQ) antibiotics are not uncommonly prescribed for community-acquired pneumonia that is later proven to be pulmonary tuberculosis (TB). Such FLQ monotherapy may result in FLQ-resistant pulmonary TB.


METHODS
To assess outpatient FLQ use by patients with culture-proven pulmonary TB before diagnosis, TB registries in Alberta and Saskatchewan, Canada, were linked with provincial and federal drug benefit plans. To assess FLQ resistance, a case-control study was performed.


RESULTS
Of 428 patients with pulmonary TB who were covered by a drug benefit plan, 74 (17.3%) had received > or = 1 FLQ prescription during the 6 months immediately before receipt of the diagnosis. Older patients (age, >64 years) were more likely than younger patients (age, 15-64 years) to be prescribed an FLQ (P < .05). Patients who were prescribed an FLQ received a total of 103 prescriptions. Most (54 [73.0%] of 74) patients who were prescribed an FLQ received a single prescription. Most (69 [67.0%] of 103) FLQ prescriptions were written within 90 days before the diagnosis of pulmonary TB. Patients who were prescribed an FLQ were not statistically significantly more likely than matched patients who were not prescribed an FLQ (control subjects) to be infected with FLQ-resistant Mycobacterium tuberculosis. Of 148 isolates of M. tuberculosis from patients and control subjects, 3 were FLQ resistant; all of these isolates were from patients who had received multiple FLQ prescriptions. Patients who had received multiple FLQ prescriptions were more likely than patients who had received a single FLQ prescription to be infected with FLQ-resistant M. tuberculosis (15.0% vs. 0.0%; odds ratio, 11.4; P = .04).


CONCLUSIONS
Outpatient FLQ use, ostensibly for community-acquired pneumonia, is not uncommon among patients with pulmonary TB, especially older patients. Single FLQ prescriptions were not associated with FLQ-resistant M. tuberculosis, whereas multiple FLQ prescriptions were associated with FLQ resistance.
Department of Medicine, University of Alberta, Edmonton, Alberta. richard.long@ualberta.ca
Richard
R
Long
Huey
H
Chong
Vernon
V
Hoeppner
Hareishun
H
Shanmuganathan
Kinga
K
Kowalewska-Grochowska
Cary
C
Shandro
Jure
J
Manfreda
Ambikaipakan
A
Senthilselvan
Abeer
A
Elzainy
Thomas
T
Marrie
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta; D017714:Community-Acquired Infections / Q000188:drug therapy*; D024881:Drug Resistance, Bacterial; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D010045:Outpatients; D011014:Pneumonia / Q000188:drug therapy*; D012525:Saskatchewan; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000382:microbiology*; D055815:Young Adult
D024841:Fluoroquinolones