Background: Extended spectrum beta lactamases (ESBL) are responsible
for increased resistance to third generation cephalosporins. Proteus species is an important
cause of both community acquired and nosocomial infections. The Proteus
species is usually susceptible to beta lactam drugs but there is progressive increase in
beta lactam resistance and recently, ESBLs are also fast spreading to this species.
Objective: This study was conducted to study ESBL production and occurrence of
TEM, SHV and CTX-M beta lactamases in clinical isolates of Proteus species in a
tertiary care center.
Method: This prospective hospital based study was carried out in Microbiology,
Kasturba Medical College, Mangalore over 9 months. All non-duplicate consecutive
Proteus isolates were identified and antibiotic susceptibility testing was done. ESBL
detection was done by double disk synergy method and TEM, SHV, CTX-M genes
were detected by PCR.
Results: 84 Proteus isolates from urine (29), blood (1), respiratory secretions (2), tissue
(20) and exudates (47) were included in the study. 20.2% (17) were ESBL positive
by disk synergy method. CTX-M was present in 6, TEM in 2 and both in 9 isolates.
SHV was not present in any isolate.
Conclusion: Our findings showed that 20% of clinical isolates of Proteus species
were ESBL producers. 52% of ESBL positive isolates carried both TEM and CTX-M
genes followed by CTX-M alone (35%) and only 11% had TEM alone. This stresses
on the fact that ESBL detection should be done routinely in Proteus isolates and the
genotype surveyed periodically for better management.