In Vitro Activity of Oral Antimicrobial Agents against Pathogens Associated with Community-Acquired Upper Respiratory Tract and Urinary Tract Infections: A Five Country Surveillance Study.
BACKGROUND
Bacterial infections that cause community-acquired urinary tract infections (CA-UTI) and upper respiratory tract infections (CA-URTI) are most frequently treated empirically. However, an increase in antimicrobial resistance has become a problem when treating outpatients.


METHODS
This study determined the in vitro activities of oral antibiotics among 1501 pathogens from outpatients with CA-UTI and CA-URTI in medical centers during 2012 and 2013 from Argentina, Mexico, Venezuela, Russia, and the Philippines. Minimal inhibitory concentrations (MICs) were determined using broth microdilution and susceptibility defined by Clinical Laboratory Standards Institute (CLSI) and European Committee for Antimicrobial Susceptibility Testing (EUCAST) criteria.


RESULTS
Ceftibuten (MIC50, ≤0.25 mg/L) was more potent in vitro compared to other β-lactams against Enterobacteriaceae from CA-UTI. Susceptibility to fluoroquinolones using CLSI criteria varied: Argentina and Mexico (50%), the Philippines (60%), Venezuela (70%), and Russia (80%). Fosfomycin susceptibility was >90% against Enterobacteriaceae in each country. Susceptibility among Enterobacteriaceae to trimethoprim-sulfamethoxazole was 30.6-75.6% and nitrofurantoin susceptibility also varied among the countries and was higher when EUCAST breakpoints were applied (65->90%) compared to CLSI (52-84%). All Haemophilus influenzae isolates from CA-URTI were susceptible to ceftibuten, cefixime, cefpodoxime, and cefuroxime using CLSI breakpoint criteria. EUCAST criteria produced intermediate and resistant MIC values for these oral cephalosporins. Country-specific susceptibility variation for fluoroquinolones, macrolides, and trimethoprim-sulfamethoxazole was observed among Streptococcus pneumoniae and Streptococcus pyogenes from CA-URTI.


CONCLUSIONS
This study demonstrated that antimicrobial susceptibility patterns varied in the five countries investigated among pathogens from CA-UTI and CA-URTI.


BACKGROUND
Merck & Co. Inc., Kenilworth, New Jersey, USA.
International Health Management Associates, Inc., Schaumburg, IL, USA. dbiedenbach@ihmainc.com.
Douglas J
DJ
Biedenbach
International Health Management Associates, Inc., Schaumburg, IL, USA.
Robert E
RE
Badal
Merck & Co. Inc., Kenilworth, NJ, USA.
Ming-Yi
MY
Huang
Merck & Co. Inc., Kenilworth, NJ, USA.
Mary
M
Motyl
Merck & Co. Inc., Kenilworth, NJ, USA.
Puneet K
PK
Singhal
Institute of Antimicrobial Chemotherapy, Smolensk State Medical University, Smolensk, Russia.
Roman S
RS
Kozlov
Research Institute for Tropical Medicine, Manila, The Philippines.
Arthur Dessi
AD
Roman
Merck & Co. Inc., Kenilworth, NJ, USA.
Stephen
S
Marcella
Community-acquired UTI and RTI; Oral antibiotics; Prescribing practices; Resistance