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PubMed2006

[Are isolation measures needed in the hospital management of Acinetobacter baumannii colonizations-infections?].

UNLABELLED: Until 2001, the infection control department of the Besançon university hospital (France) recommended isolation precautions for all patients colonized-infected by Acinetobacter baumannii (Ab) whatever the antibiotic susceptibility of the strain. These systematic isolation procedures were given up at the beginning of 2002 since the number of colonized-infected patients remained stable from 1998 to 2001. OBJECTIVE: The aim of this study was to evaluate the impact of this decision on the risk of Ab infection. METHOD: Incidence rates of colonization-infections that were observed during years 2002 and 2003 were compared with expected incidence rate, based on data from 1998-2001 period. Infection control practices and antibiotics consumption were evaluated for each ward of hospitalisation. Genotyping made it possible to determine diversity of clones inside each unit and the whole hospital. RESULTS: The expected incidence per 1000 patients-days was 0.22 in comparison with observed data in 2002, 0.34 (CI(95%) [0.28-0.42]), and in 2003, 0.53 (CI(95%) [0.45-0.63]). The expected number of Ab bloodstream infections, about two per year compared with the observed numbers in 2002 and 2003 respectively seven and 17. The number of unit with more than three cases per year increased from seven in 1999 to 18 in 2003. Antibiotics consumption did not change significantly. CONCLUSION: Genotyping results show the importance of cross-transmission in these units. Finally, observed results suggest that some measures of isolation precautions in addition to standard precautions are needed to prevent outbreaks of Ab.

Acinetobacter Infections↗
PubMed2005

A possible link between multiple sclerosis and Creutzfeldt-Jakob disease based on clinical, genetic, pathological and immunological evidence involving Acinetobacter bacteria.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the nervous system. There is an increasingly likelihood that MS could be triggered/perpetuated by environmental (microbial) agents. Sporadic Creutzfeldt-Jakob disease (sCJD) is a relatively rare but fatal disease, which shows various clinical, genetic, pathological and immunological features through which it resembles a severe form of MS. The disease in some patients with MS may show a rapidly downhill course with death occurring within one to two years and a similar situation occurs in sCJD. The occurrence of these comparative similarities between MS and sCJD could be explained on the basis that both of these conditions might be sharing a common aetiopathogenic factor such as infection by Acinetobacter microbes and this possibility could be investigated further by carrying out immunological studies on a relatively large numbers of patients with MS and CJD.

Acinetobacter↗
PubMed2004

Identification of a new geographically widespread multiresistant Acinetobacter baumannii clone from European hospitals.

The aim of the study was to investigate the genetic diversity of Acinetobacter baumannii clinical strains that had previously been allocated to three major groups based on automated ribotyping. Forty-seven isolates from European hospitals and one isolate from a South African hospital, geographically representative of the three ribogroups (ribogroups 1, 2 and 3 with 10, 23 and 15 isolates, respectively), were analysed using the highly discriminatory fingerprinting methods AFLP and pulsed-field gel electrophoresis (PFGE). Based on AFLP data, the isolates clustered into three main groups, each corresponding to one ribogroup. Inclusion of reference strains of the previously described clones I and II, responsible for outbreaks in northwestern European hospitals, showed that ribogroups 1 and 2 correspond to clones I and II, respectively, whereas ribogroup 3 apparently represents a new clone. This clone III was found in France, The Netherlands, Italy and Spain. Clones I and II were not limited to northwestern European countries, as they were also recovered from Spain, South Africa, Poland and Italy (clone I) and from Spain, Portugal, South Africa, France, Greece and Turkey (clone II). Combined AFLP and PFGE data showed intraclonal diversity and led to the distinction of 23 different genotypes. Three genotypes, two of them belonging to clone II and one to clone III, were found in different hospitals and may correspond to subsets of isolates with a more recent clonal relationship, which emphasizes the epidemic potential of these organisms.

Acinetobacter Infections↗
PubMed2004

Distribution of tetracycline resistance genes in genotypically related and unrelated multiresistant Acinetobacter baumannii strains from different European hospitals.

The presence of tetracycline (TET) resistance genes was investigated in 49 genotypically related and unrelated multidrug-resistant Acinetobacter baumannii (MDRAB) strains from European hospitals including representatives of pan-European clones I and II. Except for one strain, all MDRAB strains displayed resistance to tetracycline (MIC range of 16 to > 512 microg/ml) but were susceptible (MIC < 4 microg/ml) or exhibited intermediate resistance (MIC of 4-8 microg/ml) to minocycline (MIN). In 37 strains, either tet(A) or tet(B) was detected and one of these strains possessed both tet(A) and tet(M). In addition, all MDRAB strains contained the aspecific efflux gene adeB irrespectively of whether they harbored tet genes or not. Repetitive DNA element (rep)-PCR fingerprinting using the (GTG)5 primer [(GTG)5-PCR] revealed that strains previously assigned to pan-European clones I and II were grouped into two separate clusters. In addition, these clusters also contained strains that had not been typed previously, indicating that (GTG)5-PCR is a valuable method for recognizing putative new members of MDRAB clones. Most, but not all, members of clones I and II were linked to the presence of either tet(A) or tet(B) and displayed different levels of TET resistance with MIC values of 32 to > 512 microg/ml and > 512 microg/ml, respectively. Of these two genes only tet(B) encodes an efflux of both TET and MIN, which was reflected by the relatively high MIC values for MIN (4 microg/ml) shown by the majority of the tet(B)-carrying clone II strains as opposed to the low MIC values for MIN (< 1 microg/ml) displayed by most tet(A)-containing clone I strains. Collectively, our phenotypic and genotypic resistance data support the therapeutic evaluation of second-generation tetracyclines like MIN as promising agents for treating MDRAB infections.

Acinetobacter Infections↗
PubMed2005

Adherence of Acinetobacter baumannii strains to human bronchial epithelial cells.

Acinetobacter baumannii is an important nosocomial pathogen, but the mechanisms contributing to its epidemicity and virulence are largely unknown. The organism is able to colonize skin and mucosal surfaces of the human host. Adherence of microorganisms to host cells is an important virulence factor as it is the initial step of the colonization process. In the present study, adherence of A. baumannii to human bronchial epithelial NCI-H(292) cells was examined by light and scanning electron microscopy. Thirty-seven strains were investigated including 18 from outbreaks, 16 not associated with outbreaks, and three for which an epidemic implication was unknown. Eight and 11 isolates belonged to European clone I and II, respectively. Two types of adherence were observed, dispersed adherence of bacteria to the cell, and adherence of clusters of bacteria at localized areas of the cells. Bacteria with dispersed adherence interacted with the epithelial cells through fimbriae, but were also entrapped by protrusions extending from the epithelial cells. Quantitative adherence varied considerably among strains but there was no significant correlation of the outbreak-associated strains with the percentage of infected cells. There was, however, a correlation between the clonal lineage and the percent of infected cells, with clone II being more adherent than clone I (P<0.05). Ten consecutive isolates from one outbreak were investigated to test whether adherence increased during passage among patients, but this appeared not to be the case. This study showed that A. baumannii adheres to human bronchial epithelial cells in vitro and that A. baumannii strains of clone II had a relatively high capacity for adhering to these cells.

Acinetobacter Infections↗
PubMed1988

Multiple intensive care unit outbreak of Acinetobacter calcoaceticus subspecies anitratus respiratory infection and colonization associated with contaminated, reusable ventilator circuits and resuscitation bags.

PURPOSE: Acinetobacter calcoaceticus subspecies anitratus (A. anitratus) can cause nosocomially and community acquired pneumonia. Source identification of the organism is often difficult. An outbreak of respiratory infection and colonization with A. anitratus affecting 93 ventilated patients in all six of a hospital's intensive care units (ICUs) over 10 months is described. PATIENTS AND METHODS: In April 1984, the infection control staff started to review positive culture results from all patients in all ICUs. At this point, information on significant isolates was recorded by patient, site, date, genus and species, and antimicrobial susceptibility. During the month of August 1984, an increased number of A. anitratus isolates from sputum began to be detected. Information was expanded to include the date of hospital admission, ICU admission, intubation, and extubation; the dates and types of all surgical procedures; the results and dates of all prior sputum cultures; and the use of nebulized bronchodilator medications. Monthly numbers of cases were compared for four months prior to the outbreak, during the outbreak, and for seven months after the outbreak. Plasmid DNA from isolates was prepared, electrophoresed, and visualized. Isolates were designated according to the molecular weights of visualized plasmids. RESULTS: Barrier precautions and improved staff handwashing did not diminish the frequency of new cases. When pasteurized, reusable ventilator circuits and resuscitation bags were cultured for the possibility of low-level contamination, 18 percent were positive for A. anitratus. Terminal ethylene oxide sterilization of these devices was associated with prompt control of the outbreak. Plasmid DNA analysis of isolates from patients involved in the outbreak, contaminated devices, and the hands of personnel responsible for device disinfection revealed two predominant plasmid profiles. After outbreak control, isolates with these profiles were found much less frequently in patient specimens. CONCLUSION: Contaminated, reusable ventilator support equipment may be a leading cause for the extent of A. anitratus in the sputum of intubated patients. This problem is potentially correctable by the use of terminal etyhlene oxide sterilization of reusable ventilator circuits and resuscitation bags.

Acinetobacter↗
PubMed2000

Postoperative endophthalmitis caused by sequestered Acinetobacter calcoaceticus.

PURPOSE: To describe postoperative endophthalmitis caused by sequestered Acinetobacter calcoaceticus. METHOD: Case report. A 40-year-old woman developed recurrence of inflammation after extracapsular cataract extraction with intraocular lens (IOL) implantation. At last recurrence, the capsular bag was studded with white deposits. Intraocular lens was removed along with capsular bag during pars plana vitrectomy. RESULTS: The capsular bag, when cultured, grew A calcoaceticus. The media remained clear with no evidence of recurrence of infection over a 3-month follow-up. CONCLUSION: Postoperative endophthalmitis similar to that caused by sequestered Propionibacterium acnes can be caused by A calcoaceticus.

Acinetobacter Infections↗
PubMed2003

Prevalence of metallo-beta-lactamase among Pseudomonas aeruginosa and Acinetobacter baumannii in a Korean university hospital and comparison of screening methods for detecting metallo-beta-lactamase.

To identify the metallo-beta-lactamases (MBLs) prevalent in Korea, a total of 130 clinical isolates of Pseudomonas aeruginosa and Acinetobacter baumannii (99 P. aeruginosa and 31 A. baumannii) with a reduced susceptibility to imipenem (IPM) and/or ceftazidime (CAZ) was subjected to PCR analyses with primers specific to bla(IMP-1), bla(VIM-1), and bla(VIM-2). In addition, inhibitor-potentiated disk diffusion methods (IPD) using two kinds of substrate-inhibitor combinations (ceftazidime-2-mercaptopropionic acid (2MPA) and imipenem-EDTA) were investigated. Thirty-three isolates (29 P. aeruginosa and 4 A. baumannii) carried bla(VIM-2) and two P. aeruginosa isolates harbored bla(IMP-1). The enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) pattern revealed that many of the VIM-2-producing P. aeruginosa isolates were clonally related, whereas the A. baumannii isolates were diverse. The inhibitor-potentiated disk diffusion test using imipenem-EDTA was highly sensitive and specific for detecting the VIM-2 producer. These results suggest that VIM-2 is an important MBL in P. aeruginosa and A. baumannii in the Korean hospital of this study and that the IMP-1-producing P. aeruginosa has also emerged. Screening for MBLs and strict infection control for these isolates will contribute to prevent further spread of resistance.

Acinetobacter↗
PubMed2003

Nosocomial multi-drug resistant Acinetobacter baumannii bloodstream infection: risk factors and outcome with ampicillin-sulbactam treatment.

The emergence of multidrug-resistant (MDR) Acinetobacter baumannii poses a therapeutic problem. The aim of this study was to assess the risk factors for nosocomial MDR-A. baumannii bloodstream infection (BSI) and the efficacy of ampicillin-sulbactam (A/S) in its treatment. Of 94 nosocomial A. baumannii BSI during the year 2000, 54% involved MDR strains, 81% of which were genetically related. Various risk factors for MDR-A. baumannii were found, of which intensive-care unit admission and prior aminoglycoside therapy were independently associated with MDR-A. baumannii acquisition on multivariate analysis. Of MDR-A. baumannii BSI cases, 65% received A/S and 35% inadequate antibiotic therapy, whereas of 43 non-MDR cases, 86% were treated according to susceptibility and 14% inappropriately with antibiotics to which these organisms were resistant. Crude mortality was comparable in the adequately treated groups. Respective mortalities among patients treated adequately and inadequately were 41.4 and 91.7% (p<0.001). Among severely ill patients, A/S therapy significantly decreased the risk of death (P=0.02 OR=7.64). MDR-A. baumannii has become highly endemic in our institution. A/S appears to be one of the last effective and safe empirical resorts for treatment of MDR A. baumannii BSI.

Acinetobacter Infections↗
PubMed2003

Bacteriological, clinical and epidemiological characteristics of hospital-acquired Acinetobacter baumannii infection in a teaching hospital.

Over an 18 month period, the bacteriological, clinical and epidemiological characteristics of nosocomial Acinetobacter baumannii infections in a teaching hospital were studied. Typing studies were performed on 38 strains isolated from 36 patients. Twenty-two of the strains were isolated during the three outbreaks. Surgery, catheterization, mechanical ventilation, and antibiotic therapy for adult patients and respiratory distress syndrome, mechanical ventilation, and prematurity for paediatric patients were the main risk factors identified. All isolates were resistant to penicillins (except ampicillin-sulbactam), cephalosporins, gentamicin, and aztreonam but susceptible to carbapenems and colistin. Resistance to tobramycin, ciprofloxacin, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, and amikacin was variable. Antibiotyping, arbitrarily-primed polymerase chain reaction (AP-PCR) and the pulse-field gel electrophoresis (PFGE) indicated the epidemiological relationship. The outbreak strains, demonstrated genetic distinction between our three outbreaks and isolates from specific areas in the hospital.

Acinetobacter Infections↗
PubMed2003

Assessment of Acinetobacter baumannii susceptibility to antiseptics and disinfectants.

Disinfection and antisepsis are of primary importance in controlling outbreaks of Acinetobacter baumannii, a nosocomial pathogen that frequently shows multiple antibiotic resistance. In this study we assessed the susceptibility of nine A. baumannii strains isolated during a sustained intensive care unit outbreak, to several antiseptics and disinfectants based on European Standards. While the tested strains showed diverse antibiotic resistance patterns, they were equally sensitive to the biocides assessed in vitro. We observed neither evidence of development of resistance to biocides over time, nor a correlation between resistance to antibiotics and a decreased susceptibility to antiseptics or disinfectants.

Acinetobacter Infections↗
PubMed1985

Epidemic spread of Acinetobacter calcoaceticus in a neurosurgical department analyzed by electronic data processing.

An epidemic spread of Acinetobacter calcoaceticus var. anitratus in two neurosurgical wards is described retrospectively and prospectively using electronic data processing. Isolation of the species from sputum preceded the isolation from CSF by 1/2-1 year. Control measures directed against spread by air and indirect contact controlled the epidemic. Reexamination of 20 selected strains from the epidemic revealed two distinct resistance patterns.

Acinetobacter↗
PubMed1996

Secondary carriage with multi-resistant Acinetobacter baumannii and Klebsiella pneumoniae in an adult ICU population: relationship with nosocomial infections and mortality.

A one year prospective, observational survey was performed to evaluate the abnormal carriage of multi-resistant Klebsiella pneumoniae and/ or Acinetobacter baumannii, to determine associated risk factors for carriage, and to correlate the abnormal carriage with infectious morbidity and mortality in the intensive care unit (ICU) of a University Hospital. Two hundred and ninety-eight patients who stayed in the ICU > 48h, and were not neutropenic, were studied. Salivary and rectal samples were obtained on admission and weekly until discharge. Out of 265 evaluable patients, 88 (33%) developed oropharyngeal and/or rectal carriage within a median of nine days. Three factors were significantly associated with abnormal carriage: higher 'severity of illness' score on admission, a threefold increase in ICU stay, and the need for mechanical ventilation. K. pneumoniae or A. baumannii accounted for 57/158 (36%) of all ICU-acquired infections (in 46 patients). They were considered as secondary endogenous infections (SEI) in 42 patients who were previously colonized with the same strains, and developed infection within a median of three days (range 0-68 days). Prolonged stay in ICU was the only factor associated with SEI in the carrier population. Mortality was significantly greater in the carrier group (43 vs 25%, P = 0.0006). Post hoc stratification suggested that abnormal carriage only influenced mortality in patients showing a low severity of illness score on admission to ICU. Abnormal carriage was found in the most severely ill patients, predisposed to secondary nosocomial infections, and could influence mortality in the less severely ill.

Acinetobacter↗
PubMed1996

Investigation of the epidemiology of hospital isolates of Acinetobacter anitratus by two molecular methods.

Two hundred and two isolates of Acinetobacter anitratus from 126 patients in 36 wards belonging to 11 specialties of a university teaching hospital were compared by ribotyping and restriction enzyme digest analysis (REA) of total DNA. Forty-six groups were defined by both techniques and there was 96 center dot 5% agreement between the methods for the designation of isolates into groups. Only two groups were endemic and circulating in the whole hospital while others were less common. Burns and intensive therapy units had the highest number of isolates and these were mainly of the two endemic groups while renal dialysis and neonatal units had isolates belonging to the less common groups. Of the 32 patients with multiple isolates, 17 were infected or colonized at different sites by two and up to four groups of A. anitratus. Both ribotyping and REA of total DNA are discriminatory methods for typing A. anitratus, however, the latter is a simpler and more rapid method and it can be used in a routine clinical laboratory.

Acinetobacter↗
PubMed1997

Nosocomial outbreak of multi-resistant Acinetobacter baumannii on a surgical ward: epidemiology and risk factors for acquisition.

Between December 1994 and April 1995, a nosocomial outbreak caused by a multi-resistant Acinetobacter baumannii, occurred on a surgical ward in our hospital. The organism was isolated from 13 patients, eight of whom were infected whereas the others were colonized. Twelve isolates were compared by cell envelope protein electrophoretic profiles and AFLP, a recently described DNA fingerprinting method. Both methods indicated that this outbreak was caused by spread of a single strain, which was identified as A. baumannii by amplified ribosomal DNA fingerprinting (ARDRA). A case-control comparison was performed to identify risk factors associated with nosocomial acquisition of A. baumannii. Risk factors for cross-colonization were length of stay, surgery, wounds and treatment with broad-spectrum antibiotics. Cross-infection with A. baumannii among patients occurred despite implementation of stringent infection control measures. The outbreak was controlled after temporary closure of the surgical ward for disinfection purposes. Patients admitted on a general surgical ward colonized or infected with multi-resistant A. baumannii strains should alert the hospital infection control team, and prompt implementation of strict infection prevention measures to prevent further spread is advised.

Acinetobacter↗
PubMed1997

Genotypic investigation of multidrug-resistant Acinetobacter baumannii infections in a medical intensive care unit.

Multi-resistant Acinetobacter baumannii isolates obtained from 13 hospitalized patients over a six-month period were evaluated. One patient had an isolate susceptible only to imipenem; the next three had isolates susceptible to imipenem and ampicillin/sulbactam; the next six patients had isolates which were susceptible to imipenem, amikacin, and ampicillin/sulbactam; while the final three patients had isolates which were susceptible to imipenem and ampicillin/sulbactam. Ten patients died, five within 10 days of a positive culture. Five of six patients with bacteraemia succumbed to the infection. DNA extracted from all isolates was amplified by polymerase chain reaction using four random primers (RAPD). The resulting band patterns were compared and strains identified. In addition, all isolates were biotyped. RAPD analysis and biotyping showed that there were two distinct strains involved. The first four patients were infected with one strain (genotype ¿A', biotype 9), the subsequent nine patients were infected with a second strain (genotype ¿B', biotype 1). These results suggested that there was patient-to-patient spread of strains. Institution of, and strict adherence to, isolation procedure and other infection control practices controlled the spread of infection. These data emphasize the need for active surveillance for multidrug-resistant organisms in critically ill patients, and the value of molecular typing of strains in a hospital setting to investigate spread of infection.

Acinetobacter↗
PubMed1999

An outbreak of neonatal infection with Acinetobacter linked to contaminated suction catheters.

An outbreak of multi-drug resistant Acinetobacter spp. infection in the neonatal unit at King Edward VIII hospital in Durban, South Africa, is described. Nine out of a total of 218 neonates were infected during the study period. The outbreak was characterized by early onset infection [median postnatal age 3 days (range 1-23 days)] in pre-term babies [median gestational age 33 weeks (range 30-35 weeks)] with an attributable mortality of 22%. The source of the outbreak, determined by ribotyping, was presumed to be contaminated suction bottles and catheters in the neonatal admission room. Five neonates were successfully treated with ciprofloxacin and amikacin. Enforcement of strict infection control practices curtailed the outbreak.

Acinetobacter↗
PubMed2003

[Acinetobacter baumannii bacteremia: clinical and prognostic features].

OBJECTIVE: The incidence, clinical features, and prognosis of bacteremia due to Acinetobacter baumannii were investigated. METHODS: Prospective study of all episodes of A. baumanii bacteremia detected during the period of January 1995 to December 1998. A. baumannii was identified using recent standard methods. RESULTS: A total of 133 episodes of bacteremia due to A. baumannii were studied, all of them nosocomial-acquired. The incidence-density diminished from 2.02 episodes per 10,000 patient-days to 0.40 episodes per 10,000 patient-days after the implementation of a control program. Most of the patients (70%) were, or had been, in the ICU when bacteremia occurred. Some 80% of patients had a chronic illness and 62% had a Hilf's severity score > 4. Among the strains identified, 74% were multidrug-resistant and 28% were imipenem-resistant. Attributable mortality was 25.6%. Multivariate analysis showed that inappropriate antibiotic treatment, septic shock, and high Hilf's severity score were associated with poorer prognosis. CONCLUSION: A. baumannii bacteremia mainly affects severely ill patients who have undergone several invasive procedures, and who may have relevant associated morbidity and mortality. Among other variables, inappropriate antibiotic treatment was a risk factor for increased mortalilty.

Acinetobacter Infections↗