G. Laurans

Coexistence of SHV-4- and TEM-24-Producing Enterobacter aerogenes Strains before a Large Outbreak of TEM-24-Producing Strains in a French Hospital

ABSTRACT In 1996, a monitoring program was initiated at the teaching hospital of Amiens, France, and carried out for 3 years. All extended-spectrum β-lactamase (ESBL)-producing Enterobacter aerogenes isolates recovered from clinical specimens were collected for investigation of their epidemiological relatedness by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and determination of the type of ESBL harbored by isoelectric focusing and DNA sequencing. Molecular typing revealed the endemic coexistence, during the first 2 years, of two clones expressing, respectively, SHV-4 and TEM-24 ESBLs, while an outbreak of the TEM-24-producing strain raged in the hospital during the third year, causing the infection or colonization of 165 patients. Furthermore, this strain was identified as the prevalent clone responsible for outbreaks in many French hospitals since 1996. This study shows that TEM-24-producing E. aerogenes is an epidemic clone that is well established in the hospitals ecology and able to spread throughout wards. The management of the outbreak at the teaching hospital of Amiens, which included the reinforcement of infection control measures, failed to obtain complete eradication of the clone, which has become an endemic pathogen.

Successive Emergence of Extended-Spectrum β-Lactamase-Producing and Carbapenemase-Producing Enterobacter aerogenes Isolates in a University Hospital

ABSTRACT Sixty-two clinical isolates of Enterobacter aerogenes resistant to expanded-spectrum cephalosporins were collected between July 2003 and May 2005. Among these isolates, 23 (37.1%) were imipenem (IPM) susceptible, and 39 (62.9%) were IPM insusceptible, of which 89.7% (35/39) were resistant and 10.3% (4/39) were intermediate. Isolate genotypes were compared by pulsed-field gel electrophoresis. Of 62 isolates, 48 belonged to epidemic pulsotype A (77.4%). This pulsotype included 37.5% and 58.4% of β-lactam phenotypes b and a, respectively. Nine isolates (14.5%) belonged to pulsotype E, which included 22.3% and 77.7% of phenotypes b and a, respectively. The β-lactamases with pIs of 5.4, 6.5, 8.2, and 8.2 corresponded to extended-spectrum β-lactamases (ESBLs) TEM-20, TEM-24, SHV-5, and SHV-12, respectively. Of 39 IPM-insusceptible E. aerogenes isolates, 26 (66.6%) were determined to be metallo-β-lactamase producers, by using a phenotypic method. Of these isolates, 24 harbored a blaIMP-1 gene encoding a protein with a pI of >9.5, and two carried the blaVIM-2 gene encoding a protein with a pI of 5.3, corresponding to β-lactamases IMP-1 and VIM-2, respectively. The remaining 13 (33.4%) isolates were negative for the blaIMP-1 and blaVIM-2 genes but showed an alteration of their outer membrane proteins (OMPs). Ten of these isolates produced the two possible OMPs (32 and 42 kDa), with IPM MICs between 8 and 32 μg/ml, and three others produced only a 32-kDa OMP with IPM MICs >32 μg/ml. This work demonstrates that, in addition to resistance to expanded-spectrum cephalosporins, IPM resistance can occur in ESBL-producing E. aerogenes isolates by carbapenemase production or by the loss of porin in the outer membrane.

Molecular typing and characterization of extended-spectrum TEM, SHV and CTX-M β-lactamases in clinical isolates of Enterobacter cloacae

Sixty-one non-repetitive Enterobacter cloacae ESBL producers were collected at the Amiens University Hospital in France. Eight beta-lactam resistance phenotypes (a-h) and three aminoglycoside resistance phenotypes (i-k) were identified among these isolates, and 32 different pulsotypes were observed. Of these 61 isolates, 37 were sequenced and found to harbor beta-lactamases with a pI of 5.9 (TEM-4), 6.5 (TEM-24), 7.8 (SHV-4), 8.2 (SHV-12), 8.4 (CTX-M-1) and 8.0 (CTX-M-9). Four imipenem-resistant ESBL-producing E. cloacae isolates did not express the 38kDa OMP, indicating that this resistance is associated with porin deficiency.

Nocardia nova as the Causative Agent in Spondylodiscitis and Psoas Abscess

ABSTRACT We describe here the first case of Nocardia nova spondylodiscitis accompanied by a psoas abscess due to spreading from pulmonary nocardiosis. Nocardia was cultured from all affected sites. After 1 year of an appropriate antimicrobial therapy and a surgical drainage of the abscess that was required, the patients clinical condition had improved.

Molecular epidemiology of ampicillin-resistant clinical isolates of Salmonella enterica serovar Typhimurium

Thirty-nine multiresistant Salmonella enterica serovar Typhimurium (S. Typhimurium) isolates were obtained from 33 children and 6 adults hospitalized from 1996 to 1999 in the University Hospital of Amiens (France). S. Typhimurium was cultured from stools (n=36), blood samples (n=2) and peritoneal fluid (n=1). These isolates were characterized by biotyping, antibiotic susceptibility test, RAPD-PCR, and PFGE typing. Emergence of pentaresistant S. Typhimurium isolates (phenotype ACSSuTe) was observed, and five of them were resistant to nalidixic acid and of intermediate susceptibility to pefloxacin. Genotypic analysis of both RAPD and PFGE results showed that there were 7 different patterns. Thirty-three isolates gave an identical pattern (AI) and were considered as epidemic isolates; the six remaining patterns (each containing one isolate) corresponded to sporadic cases. Antibiotic susceptibility patterns, RAPD and PFGE patterns subdivided the 39 isolates into 9 clonally related groups. One of them (pattern AI and R-pattern a) was implicated in 74% of the cases.