TY - JOUR
T1 - Spread of multidrug-resistant Proteus mirabilis isolates producing an AmpC-type β-lactamase
T2 - epidemiology and clinical management
AU - Luzzaro, Francesco
AU - Brigante, Gioconda
AU - D'Andrea, Marco Maria
AU - Pini, Beatrice
AU - Giani, Tommaso
AU - Mantengoli, Elisabetta
AU - Rossolini, Gian Maria
AU - Toniolo, Antonio
PY - 2009/4
Y1 - 2009/4
N2 - A remarkable increase in Proteus mirabilis strains producing acquired AmpC-type β-lactamases (CBLs) has been observed at Ospedale di Circolo e Fondazione Macchi (Varese, Italy) over the last few years. The epidemiology and treatment outcome of infections associated with this unprecedented spread are reported. From 2004-2006, 2070 P. mirabilis isolates were investigated. Extended-spectrum β-lactamases (ESBLs) and CBL resistance determinants were identified by gene amplification and direct sequencing. Clonal relatedness was evaluated by macrorestriction analysis. Overall, 43 CBL-positive isolates were obtained from hospitalised (n = 22) and non-hospitalised (n = 21) patients (median age 78.8 years). The prevalence of CBL-positive isolates increased from 0.3% in 2004 to 4.6% in 2006, whereas that of ESBL-positive isolates remained constant (ca. 10%). CBL-positive isolates were multidrug-resistant and carried the CMY-16 determinant. All but two isolates were genetically identical or closely related. Retrospective analysis of clinical records revealed that the majority of CMY-16-positive isolates were associated with urinary tract infections. Treatment with amikacin or carbapenems was consistently effective, whereas piperacillin/tazobactam produced a clinical response in seven of nine cases. This is the first report of a rapid spread of CBL-positive P. mirabilis strains endowed with remarkable antimicrobial resistance. Practical methods for CBL detection are needed for the appropriate management of related infections.
AB - A remarkable increase in Proteus mirabilis strains producing acquired AmpC-type β-lactamases (CBLs) has been observed at Ospedale di Circolo e Fondazione Macchi (Varese, Italy) over the last few years. The epidemiology and treatment outcome of infections associated with this unprecedented spread are reported. From 2004-2006, 2070 P. mirabilis isolates were investigated. Extended-spectrum β-lactamases (ESBLs) and CBL resistance determinants were identified by gene amplification and direct sequencing. Clonal relatedness was evaluated by macrorestriction analysis. Overall, 43 CBL-positive isolates were obtained from hospitalised (n = 22) and non-hospitalised (n = 21) patients (median age 78.8 years). The prevalence of CBL-positive isolates increased from 0.3% in 2004 to 4.6% in 2006, whereas that of ESBL-positive isolates remained constant (ca. 10%). CBL-positive isolates were multidrug-resistant and carried the CMY-16 determinant. All but two isolates were genetically identical or closely related. Retrospective analysis of clinical records revealed that the majority of CMY-16-positive isolates were associated with urinary tract infections. Treatment with amikacin or carbapenems was consistently effective, whereas piperacillin/tazobactam produced a clinical response in seven of nine cases. This is the first report of a rapid spread of CBL-positive P. mirabilis strains endowed with remarkable antimicrobial resistance. Practical methods for CBL detection are needed for the appropriate management of related infections.
KW - Antimicrobial resistance
KW - Enterobacteriaceae
KW - Epidemiology
KW - Outcome
KW - Treatment
UR - http://www.scopus.com/inward/record.url?scp=61449240014&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=61449240014&partnerID=8YFLogxK
U2 - 10.1016/j.ijantimicag.2008.09.007
DO - 10.1016/j.ijantimicag.2008.09.007
M3 - Article
C2 - 19095415
AN - SCOPUS:61449240014
VL - 33
SP - 328
EP - 333
JO - International Journal of Antimicrobial Agents
JF - International Journal of Antimicrobial Agents
SN - 0924-8579
IS - 4
ER -