Joaquín R. Otero

Nosocomial Spread of Colistin-Only-Sensitive Sequence Type 235 Pseudomonas aeruginosa Isolates Producing the Extended-Spectrum β-Lactamases GES-1 and GES-5 in Spain

ABSTRACT The mechanisms responsible for the increasing prevalence of colistin-only-sensitive (COS) Pseudomonas aeruginosa isolates in a Spanish hospital were investigated. Pulsed-field gel electrophoresis revealed that 24 (50%) of the studied isolates belonged to the same clone, identified as the internationally spread sequence type 235 (ST235) through multilocus sequence typing. In addition to several mutational resistance mechanisms, an integron containing seven resistance determinants was detected. Remarkably, the extended-spectrum β-lactamase GES-1 and its Gly170Ser carbapenem-hydrolyzing derivative GES-5 were first documented to be encoded in a single integron. This work is the first to describe GES enzymes in Spain and adds them to the growing list of β-lactamases of concern (PER, VIM, and OXA) detected in ST235 clone isolates.

Emergencia de un clon de Staphylococcus aureus resistente a meticilina de origen comunitario en la población pediátrica del sur de Madrid

Introduccion El aparente incremento en el numero de aislamientos de Staphylococcus aureus resistentes a meticilina (SARM) en pacientes pediatricos atendidos en nuestro hospital nos llevo a estudiar sus caracteristicas microbiologicas, epidemiologicas y clinicas. Se estudio con especial atencion su possible origen comunitario. Metodos Se realizo un estudio retrospectivo de todos los pacientes pediatricos atendidos en el Hospital 12 de Octubre con aislamientos clinicos de SARM. El periodo de estudio fue de enero de 2002 a junio de 2005. Se distinguio entre infecciones de adquisicion intrahospitalaria, asociada o relacionada con el sistema sanitario, y extrahospitalaria (adquirida en la comunidad). Los aislamientos de SARM se estudiaron mediante electroforesis en campo pulsante (ECP), tipificacion del elemento SCCmec y determinacion de la presencia del gen que codifica la leucocidina de Panton-Valentine (LPV). Resultados Se aislo SARM de 17 pacientes. De estos, 7 aislamientos (42,2%) eran de origen comunitario, correspondientes a 4 casos de infeccion cutanea y/o de partes blandas, dos otitis y una piomiositis bacteriemica. De los 7 aislamientos de origen comunitario, seis tenian el mismo patron de ECP (genotipo D), presentaban el tipo IV de SSCmec, producian la toxina LPV y eran unicamente resistentes a la oxacilina. Conclusion Este estudio constata, creemos que por primera vez en Espana, la presencia de estas cepas comunitarias de SARM. El posible incremento en la incidencia de infecciones por SARM en ninos fuera del ambiente hospitalario tiene importantes implicaciones tanto para las posibles estrategias de salud publica como para el tratamiento correcto.

Systematic screening and treatment of asymptomatic bacteriuria in renal transplant recipients

We sought to examine the impact of asymptomatic bacteriuria on renal transplant outcome by retrospectively analyzing 189 renal transplant recipients for whom systematic screening uncovered 298 episodes of asymptomatic bacteriuria in 96 recipients. These patients were treated and all were followed for 36 months. Significant risk factors included female gender, glomerulonephritis as the disease that led to transplantation, and double renal transplant. There were no differences in serum creatinine, creatinine clearance, or proteinuria between patients with and without bacteriuria. The incidence of pyelonephritis in these patients was 7.6 episodes per 100 patient-years compared with 1.07 in those without asymptomatic bacteriuria. Between two to five and more than five bacteriuria episodes were significant independent factors associated with pyelonephritis whereas more than five episodes was a significant independent factor associated with rejection. Thus, we found no differences in renal function prognosis between patients who do not develop asymptomatic bacteriuria and those uncovered by systematic screening and who received treatment following kidney transplantation. Despite this treatment, the incidence of pyelonephritis was much higher in the group of patients with detected asymptomatic bacteriuria.

Nosocomial spread of colistin-only-sensitive (COS) ST235 Pseudomonas aeruginosa producing the extended-spectrum β-lactamases GES-1 and GES-5 in Spain

ABSTRACT The mechanisms responsible for the increasing prevalence of colistin-only-sensitive (COS) Pseudomonas aeruginosa isolates in a Spanish hospital were investigated. Pulsed-field gel electrophoresis revealed that 24 (50%) of the studied isolates belonged to the same clone, identified as the internationally spread sequence type 235 (ST235) through multilocus sequence typing. In addition to several mutational resistance mechanisms, an integron containing seven resistance determinants was detected. Remarkably, the extended-spectrum β-lactamase GES-1 and its Gly170Ser carbapenem-hydrolyzing derivative GES-5 were first documented to be encoded in a single integron. This work is the first to describe GES enzymes in Spain and adds them to the growing list of β-lactamases of concern (PER, VIM, and OXA) detected in ST235 clone isolates.

VIM-2-producing multidrug-resistant Pseudomonas aeruginosa ST175 clone, Spain.

This clone is a major public health problem because it limits antimicrobial drug therapy.

Multidrug-resistant Acinetobacter baumannii Harboring OXA-24 carbapenemase, Spain.

In February 2006, a patient colonized with a multidrug-resistant sequence type 56 Acinetobacter baumannii strain was admitted to a hospital in Madrid, Spain. This strain spread rapidly and caused a large outbreak in the hospital. Clinicians should be alert for this strain because its spread would have serious health consequences.

Panton-Valentine leukocidin-positive Staphylococcus aureus skin and soft tissue infections among children in an emergency department in Madrid, Spain.

Fifty-three children who attended the emergency department with community-associated (CA) Staphylococcus aureus skin and soft tissue infections (SSTIs) were enrolled in the study. Seven cases of infection (13.2%) were due to methicillin-resistant S. aureus (MRSA). Twelve of 46 available isolates (26.1%) were Panton-Valentine leukocidin (PVL)-positive. PVL-positive S. aureus SSTIs were more frequently associated with abscesses and cellulitis (75% vs. 38%, p 0.028), and more commonly required incision and drainage (75% vs. 21%, p 0.001). Most PVL-positive CA-MRSA isolates belonged to a single multilocus sequence type (ST8). In contrast, PVL-positive methicillin-susceptible S. aureus isolates belonged to four different sequence types (ST8, ST30, ST80, ST120).

Prospective randomized trial of efficacy of ganciclovir versus that of anti-cytomegalovirus (CMV) immunoglobulin to prevent CMV disease in CMV-seropositive heart transplant recipients treated with OKT3.

We compared the efficacy of ganciclovir versus that of cytomegalovirus (CMV) immunoglobulin for the prevention of CMV disease in 31 CMV-seropositive heart transplant recipients who had received early immunoprophylaxis with OKT3 monoclonal antibodies. The incidence of CMV disease and visceral involvement was much higher in the CMV immunoglobulin group than in the ganciclovir group (40 versus 6%, respectively; P = 0.03). No adverse effects were found in the CMV immunoglobulin group, but 19% of the patients in the ganciclovir group developed mild leukopenia or a mild increase in their serum creatinine levels.

Clinical and Molecular Characteristics of Infections with CO2-Dependent Small-Colony Variants of Staphylococcus aureus

ABSTRACT Most Staphylococcus aureus small-colony variants (SCVs) are auxotrophs for menadione, hemin, or thymidine but rarely for CO2. We conducted a prospective investigation of all clinical cases of CO2-dependent S. aureus during a 3-year period. We found 14 CO2-dependent isolates of S. aureus from 14 patients that fulfilled all requirements to be considered SCVs, 9 of which were methicillin resistant. The clinical presentations included four cases of catheter-related bacteremia, one complicated by endocarditis; two deep infections (mediastinitis and spondylodiscitis); four wound infections; two respiratory infections; and two cases of nasal colonization. Pulsed-field gel electrophoresis typing showed that the 14 isolates were distributed into 4 types corresponding to sequence types ST125-agr group II (agrII), ST30-agrIII, ST34-agrIII, and ST45-agrI. An array hybridization technique performed on the 14 CO2-dependent isolates and 20 S. aureus isolates with normal phenotype and representing the same sequence types showed that all possessed the enterotoxin gene cluster egc, as well as the genes for α-hemolysin and δ-hemolysin; biofilm genes icaA, icaC, and icaD; several microbial surface components recognizing adhesive matrix molecules (MSCRAMM) genes (clfA, clfB, ebh, eno, fib, ebpS, sdrC, and vw); and the isaB gene. Our study confirms the importance of CO2-dependent SCVs of S. aureus as significant pathogens. Clinical microbiologists should be aware of this kind of auxotrophy because recovery and identification are challenging and not routine. Further studies are necessary to determine the incidence of CO2 auxotrophs of S. aureus, the factors that select these strains in the host, and the genetic basis of this type of auxotrophy.

Nosocomial spread of linezolid-resistant Staphylococcus haemolyticus infections in an intensive care unit.

This report documents the nosocomial spread for an 18-month period of a single clone of linezolid- and teicoplanin-resistant Staphylococcus haemolyticus associated primarily with catheter-related bacteremia in intensive care unit patients. All linezolid-resistant isolates had the same G2576T mutation in at least 1 copy of the 23S rRNA gene.