Large Outbreak in a Surgical Intensive Care Unit of Colonization or Infection with<i>Pseudomonas aeruginosa</i>that Overexpressed an Active Efflux Pump

Bertrand, Xavier; Bailly, Pascale; Blasco, Gilles; Balvay, P.; Boillot, A.; Talon, D.

doi:10.1086/318117

Cited by 45 publications

(32 citation statements)

References 22 publications

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“…While a few previous studies have reported on the clonal spread of P. aeruginosa isolates overexpressing an efflux pump (3,12), to the best of our knowledge, this is the first description of an outbreak caused by a P. aeruginosa strain that simultaneously hyperproduced MexXY-OprM and produced an integron-borne PSE-1 ␤-lactamase. These two resistance mechanisms have previously been reported among P. aeruginosa isolates that are more resistant to FEP than to CAZ (16).…”

Section: Discussionmentioning

confidence: 70%

Nosocomial Outbreak of a Non-Cefepime-Susceptible Ceftazidime-Susceptible Pseudomonas aeruginosa Strain Overexpressing MexXY-OprM and Producing an Integron-Borne PSE-1 ß-Lactamase

et al. 2009

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Pseudomonas aeruginosa is an opportunistic pathogen that causes a variety of nosocomial infections. Cefepime (FEP) and ceftazidime (CAZ) are broad-spectrum cephalosporins that display similar MICs for wild-type P. aeruginosa strains. Although the rates of susceptibility of these two antipseudomonal cephalosporins appear to be identical for P. aeruginosa isolates in the United States (20), several European studies have recently reported an unusual discordance in the MICs of FEP and CAZ (4, 6, 7), with P. aeruginosa isolates being less susceptible to the former cephalosporin.The most frequent mechanisms of resistance to extendedspectrum cephalosporins in P. aeruginosa are derepression of the chromosomal AmpC ß-lactamase, the impermeability of the outer membrane, and increased efflux (9). FEP, in contrast to CAZ, is efficiently extruded by various efflux pumps, including the MexCD-OprJ and MexXY-OprM efflux pumps (16,22). In addition, previous studies have noted the selectively reduced susceptibility to FEP among P. aeruginosa strains producing OXA ß-lactamases (2), as opposed to those that produce class A extended-spectrum ß-lactamases (32), which usually confer resistance to CAZ and FEP.In response to an increase in the incidence of carbapenemresistant and multidrug-resistant P. aeruginosa isolates in the Hospital de Bellvitge, Barcelona, Spain, since 2004, a microbiology surveillance program was introduced. Recently, however, P. aeruginosa isolates showing variable susceptibilities to carbapenems and a discordance in susceptibility between CAZ and FEP have been noted. A clustering of the P. aeruginosa non-FEP-susceptible and CAZ-susceptible (Fep ns Caz s ) phenotype was suspected in the hospital's intensive care unit (ICUs). Here we elucidate the clinical and molecular epidemiology of the isolates with this discordant phenotype and the resistance mechanisms involved. MATERIALS AND METHODSHospital setting. The Hospital de Bellvitge is a university-affiliated public institution for adult patients located in Barcelona, Spain. It contains 900 beds for acute medical and surgical care but no wards for pediatrics, obstetrics, or burns. The hospital has two 12-bed medical-surgical ICUs managed by separate teams of medical and nursing staff. The paramedical care providers (physiotherapists, radiographic personnel, nutrition support team) have contact with patients in both ICU units. All rooms in the ICUs are single.Data collection-outbreak detection.

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Section: Discussionmentioning

confidence: 70%

Nosocomial Outbreak of a Non-Cefepime-Susceptible Ceftazidime-Susceptible Pseudomonas aeruginosa Strain Overexpressing MexXY-OprM and Producing an Integron-Borne PSE-1 ß-Lactamase

et al. 2009

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“…During the survey period, 201 patients admitted to the hospital in Besançon were colonized and/or infected by an epidemic clone of P. aeruginosa serotype O:6. The outbreak was initially detected in the surgical ICU in May 1999 (8). However, a retrospective study showed that the epidemic strain was already present in the institution in May 1997.…”

Section: Resultsmentioning

confidence: 99%

“…We recently witnessed the propagation of a multiresistant P. aeruginosa epidemic clone in the surgical intensive care unit (ICU) of the Besançon public hospital, France (8). The outbreak was controlled in the ward after implementation of strict hygiene measures but has disseminated inside and outside the hospital since then, affecting more than 200 patients.…”

mentioning

confidence: 99%

Genetic and Phenotypic Variations of a ResistantPseudomonas aeruginosaEpidemic Clone

Hocquet¹,

Bertrand

Köhler³

et al. 2003

Antimicrob Agents Chemother

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Although constitutively overproduced in these bacteria, the MexXY efflux system did not appear to contribute significantly to aminoglycoside resistance. ␤-Lactam resistance was associated with derepression of intrinsic AmpC ␤-lactamase (with isolate-to-isolate variations of up to 58-fold) and sporadic deficiency in a 46-kDa protein identified as the carbapenem-selective porin OprD. Of the 18 isolates, 14 were also found to overproduce the efflux system MexAB-OprM as a result of alteration of the repressor protein MexR (His1073Pro). However, complementation experiments with the cloned mexR gene demonstrated that MexAB-OprM contributed only marginally to ␤-lactam and fluoroquinolone resistance. Of the four isolates exhibiting wild-type MexAB-OprM expression despite the MexR alteration, two appeared to harbor secondary mutations in the mexA-mexR intergenic region and one harbored secondary mutations in the putative ribosome binding site located upstream of the mexAB oprM operon. In conclusion, this study shows that many mechanisms were involved in the multiresistance phenotype of this highly epidemic strain of P. aeruginosa. Our results also demonstrate that the clone sporadically underwent substantial genetic and phenotypic variations during the course of the outbreak, perhaps in relation to local or individual selective drug pressures.

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“…Bearing in mind that the probability of developing resistance during treatment is close to 10% [5], it is possible that a patient having a longer stay in hospital and greater exposure to different antibiotics [18], sequencially [7], may develop resistance, especially in the context of cross transmission in a small unit [16]. Bertrand et al, have described a large-scale epidemic in a surgical ICU which lasted 55 months [19]. No environmental reservoir was identified, but colonisation of health personnel's hands was documented.…”

Section: Discussionmentioning

confidence: 99%

Identifying and controlling a multiresistant pseudomonas aeruginosa outbreak in a latin-american cancer centre and its associated risk factors

Cortés¹,

Cuervo²,

Urdaneta³

et al. 2009

Braz J Infect Dis

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Pseudomonas aeruginosa is an important and frightening microorganism for patients suffering from cancer. Multiresistant P. aeruginosa (MRPA) may appear as a consequence of exposure to multiple antibiotics or from a breakdown in infection control practices. This article reports an MRPA outbreak in a cancer treatment centre and the consequent case control study. Mechanical ventilation was identified as being the main risk factor for developing MRPA colonisation or infection; molecular analysis confirmed the outbreak. A multifaceted strategy was adopted, involving reinforcing hand-washing practices, contact isolation, antibiotic restriction and suction devices for mechanically-ventilated patients. MRPA was controlled and the outbreak ended. Such strategy may be effective in controlling MRPS in low-resource environments amongst high risk cancer patients.

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Large Outbreak in a Surgical Intensive Care Unit of Colonization or Infection withPseudomonas aeruginosathat Overexpressed an Active Efflux Pump

Cited by 45 publications

References 22 publications

Nosocomial Outbreak of a Non-Cefepime-Susceptible Ceftazidime-Susceptible Pseudomonas aeruginosa Strain Overexpressing MexXY-OprM and Producing an Integron-Borne PSE-1 ß-Lactamase

Nosocomial Outbreak of a Non-Cefepime-Susceptible Ceftazidime-Susceptible Pseudomonas aeruginosa Strain Overexpressing MexXY-OprM and Producing an Integron-Borne PSE-1 ß-Lactamase

Genetic and Phenotypic Variations of a ResistantPseudomonas aeruginosaEpidemic Clone

Identifying and controlling a multiresistant pseudomonas aeruginosa outbreak in a latin-american cancer centre and its associated risk factors

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