ABSTRACT
BACKGROUND: Data on superinfections in patients with ventilator-associated pneumonia vary, but different pathogens are typically studied as a single category. We studied the incidence of superinfections and the outcomes of patients with superinfections in Pseudomonas aeruginosa ventilator-associated pneumonia. METHODS: Sixty patients with Pseudomonas aeruginosa ventilator-associated pneumonia were initially treated appropriately. On day three of follow-up, bronchoalveolar lavage was collected. For Pseudomonas aeruginosa species that reached >104 colony forming units/ml upon follow-up, bronchoalveolar lavage pulsed gel field electrophoresis was applied. Accordingly, Pseudomonas aeruginosa was identified as a superinfection when isolates were genetically unrelated to those isolated at study entry or as a persistence of infection when isolates were closely related. RESULTS: Upon follow-up, 15 (25%) patients displayed superinfections with Pseudomonas aeruginosa that was resistant to the initial antibiotic regimen. Forty-five (75%) patients did not have a superinfection upon follow-up. Among these patients, 18 (30%) had a persistent infection , as determined by the significant counts of initial Pseudomonas aeruginosa isolates that had developed resistance, and 27 (45%) had persistence in which insignificant counts of initial Pseudomonas aeruginosa isolates remained sensitive to the initial antibiotics. Antibiotic treatment was adjusted for patients with superinfections and persistence with the development of resistance. The Simplified Acute Physiology Score (45.1±4.9 versus 43±4.9, P=0.38), the Sequential Organ Failure Assessment (4.13±2.5 versus 4.7±2.7, P=0.53) and mortality (20% versus 17.7%, P~1.00) were comparable on day-14 for patients with and without a superinfection. CONCLUSION: For Pseudomonas aeruginosa ventilator-associated pneumonia, superinfections are not uncommon as early as day three, but they do not increase mortality.
Subject(s)
Pneumonia, Ventilator-Associated/microbiology , Pseudomonas Infections/microbiology , Superinfection/microbiology , APACHE , Anti-Bacterial Agents/therapeutic use , Bronchoalveolar Lavage , Bronchoalveolar Lavage Fluid/microbiology , Female , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Multiple Organ Failure/pathology , Pneumonia, Ventilator-Associated/drug therapy , Prospective Studies , Pseudomonas Infections/drug therapy , Research Design , Superinfection/drug therapy , Treatment OutcomeABSTRACT
Fifty-two isolates of Acinetobacter spp. obtained from three Greek and one UK hospital, were studied using partial 16 S ribosomal DNA sequence analysis, repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR) mediated fingerprinting and DNA macro-restriction analysis. The aim was twofold: first, to discern the major differences in the population of Acinetobacter spp. between the two countries. Second, to compare a simple PCR-based typing scheme with pulsed-field gel electrophoresis (PFGE). The multi-resistant Greek isolates were within DNA groups 2 and TU13, and clustered into three types both by REP-PCR and PFGE. By contrast, the more susceptible Oxford isolates were heterogeneous on 16 S RNA sequence analysis and distinguishable on typing. The need for studies that elucidate the phylogeny of Acinetobacter spp. inside and outside hospitals are important, as this will help clarify the relationship between organisms that are increasingly recognized as causes of severe infections.
