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PubMed1979

Serological cross-reactions between Acinetobacter calcoaceticus and chlamydiae.

A cross-reaction between Acinetobacter calcoaceticus and chlamydiae is described. A water-soluble, heat stable, non-dialyzable antigen was extracted from Acinetobacter species by boiling. This antigen fixed complement in the presence of homologous hyperimmune sera from rabbits or guinea pigs and in the presence of heterologous human or hyperimmunized animal sera containing chlamydial antibodies. Hyperimmune antisera to the extracted antigen, or to suspensions of live acinetobacters, also reacted in complement fixation with a group-specific antigen.

Acinetobacter↗
PubMed1990

Species, biotype, and bacteriophage type determinations compared with cell envelope protein profiles for typing Acinetobacter strains.

Species, biotypes, and phage types were determined for 120 Acinetobacter strains from clinical or environmental sources or from culture collections. These characteristics were compared with cell envelope protein profiles obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in previous studies. A considerable heterogeneity of species and types was observed by use of the various methods, in particular among strains from different sources. Acinetobacter baumannii was the most commonly found species in isolates from clinical sources, followed by Acinetobacter species 3. Nine biotypes were observed among A. baumannii strains. Further differentiation within most species and biotypes was achieved by protein profile typing and, to some extent, phage typing. Of 120 strains, 49 (41%) were not typeable by phages. Consistent results for the various classification methods were obtained for strains from common sources. Biotyping seemed an appropriate method for the screening of strains, whereas protein profile and phage typing could serve as additional methods to establish the identity or nonidentity of strains. Results of this study suggest that the combination of the typing methods is useful in epidemiological studies.

Acinetobacter↗
PubMed2003

Evaluation of the Hodge test and the imipenem-EDTA double-disk synergy test for differentiating metallo-beta-lactamase-producing isolates of Pseudomonas spp. and Acinetobacter spp.

Gram-negative bacilli with acquired metallo-beta-lactamase (MBL) production have been increasingly reported in some countries, necessitating their detection. The aim of this study was to evaluate the performance of the Hodge test and those of the imipenem (IPM)-EDTA, ceftazidime (CAZ)-mercaptopropionic acid (MPA), and CAZ-sodium mercaptoacetic acid (SMA) double-disk synergy tests (DDSTs). The efficiencies of testing CAZ-resistant and IPM-nonsusceptible isolates were also compared. Strains used for the evaluation were known IMP-1 and VIM-2 MBL-producing isolates and consecutive and CAZ-nonsusceptible isolates of pseudomonads and acinetobacters. The performance of the Hodge test was improved by addition of zinc sulfate (140 microg/disk) to an IPM disk. In DDSTs, EDTA (ca. 1,900 microg) disks were better at detecting MBL-producing strains among pseudomonads, while MPA (3 microl) and SMA (3 mg) disks performed better for acinetobacters. EDTA (ca. 750 microg)-plus-SMA (ca. 2 mg) disks performed better than EDTA, MPA, or SMA disks with both organisms. CAZ-SMA DDSTs failed to detect 22 of 80 (28%) MBL-producing acinetobacters. In conclusion, use of an IPM disk and an EDTA (750 microg)-plus-SMA (2 mg) disk improves performance, and testing IPM-nonsusceptible isolates rather than CAZ-resistant isolates could reduce screening work. Further evaluation of the test is required for the detection of other types of MBL-producing gram-negative bacilli.

Acinetobacter↗
PubMed1992

Evaluation of Mast-ID 15 system for identification of fresh clinical isolates of Enterobacteriaceae and Acinetobacter.

AIMS: To assess the accuracy of the Mast-ID 15 system compared with API 20 E for the identification of stock and fresh clinical strains of Enterobacteriaceae and Acinetobacter spp; to compare the accuracy of 19 pin and 36 pin multipoint inoculator heads. METHODS: One hundred frozen stock cultures of Enterobacteriaceae and Acinetobacter spp which had previously been identified by the API 20E were classified by the Mast-ID using 19 and 36 pin multipoint inoculator heads. Reproducibility was determined by testing 36 randomly selected organisms in duplicate. Four hundred and sixty nine consecutive fresh clinical isolates of Enterobacteriaceae and Acinetobacter spp were identified by the Mast-ID using a 36 pin multipoint inoculator and by the API 20E. Reproducibility for the fresh isolates was determined by testing 96 randomly selected strains in duplicate. RESULTS: The Mast-ID 15 identified 82% and 85% of frozen strains to species level and reproducibility was 80% and 86% using 19 and 36 pin inoculator heads, respectively. Of the 469 fresh clinical isolates, the Mast-ID identified 70% of strains to species level; 19% were not identified and 11% were identified incorrectly by comparison with the API 20E. The Mast-ID achieved a reproducibility level of 80% with the fresh clinical isolates. CONCLUSIONS: The use of a 36 pin multipoint inoculator head in preference to the standard 19 pin head for the Mast-ID was advantageous as it allowed greater numbers of strains to be identified at a reduced cost. Unfortunately, in our hands, the Mast-ID system was insufficiently accurate for routine use in the clinical laboratory. Modifications to some of the problematic tests may result in a sufficient increase in accuracy and reproducibility to make the system beneficial in the routine clinical laboratory.

Acinetobacter↗
PubMed1980

A common source outbreak of Acinetobacter pulmonary infections traced to Wright respirometers.

Over a 30-day period, Acinetobacter calcoaceticus var. antiratus was the responsible pathogen for hospital-acquired pneumonia in 10 patients, and resulted in the colonization of the upper respiratory tract in an additional 9 patients. Wright respirometers contaminated by this organism were shown to be the common source for the outbreak as indicated by the recovery of a single serotype (8J), the inability to recover Acinetobacter from any other environmental source, and the demonstration that moisturized Wright respirometers are capable of "aerosolizing" fluids containing Acinetobacter.

Acinetobacter Infections↗
PubMed2004

Activity of levofloxacin and ciprofloxacin in combination with cefepime, ceftazidime, imipenem, piperacillin-tazobactam and amikacin against different Pseudomonas aeruginosa phenotypes and Acinetobacter spp.

BACKGROUND: Combination therapy is used to widen the antimicrobial spectrum, minimize toxicity and prevent the emergence of resistant mutants. METHODS: Synergy between levofloxacin or ciprofloxacin and ceftazidime, cefepime, imipenem, piperacillin-tazobactam and amikacin was evaluated by checkerboard assay with 55 strains and by time-kill curves with 8 strains of Pseudomonas aeruginosa and Acinetobacter spp. RESULTS: In the checkerboard assay, synergy and additivity were the most frequent effects observed among all the combinations against P. aeruginosa and Acinetobacter spp., with no significant differences between the two fluoroquinolones. No antagonism was observed. In the time-kill curves, synergy was evidenced against all the tested strains, at least for one combination at one of the time points considered. Levofloxacin and ciprofloxacin combined with ceftazidime, as well as levofloxacin plus amikacin, were synergistic for all the strains tested. CONCLUSION: Combinations of fluoroquinolones with beta-lactams or amikacin show an enhanced activity against P. aeruginosa and Acinetobacter spp.

Acinetobacter↗
PubMed1983

Acinetobacter contamination of laboratory dental pumice.

Micro-organisms of the genus Acinetobacter, implicated as opportunistic pathogens, have been recovered from dentures after laboratory repair. A study was undertaken to determine if Acinetobacter could be isolated from used dental pumice. Cultural studies demonstrated that Acinetobacter calcoaceticus variety lwoffi was present in high numbers in used pumice and was a major gram-negative microbial contaminant.

Acinetobacter↗
PubMed2002

Pharmacokinetic model for tobramycin in acinetobacter meningitis.

OBJECTIVE: To report a case of acinetobacter meningitis treated with a once-daily intravenous dose of tobramycin and to propose a pharmacokinetic model for the drug disposition. CASE SUMMARY: A 28-year-old man with chronic hydrocephalus was admitted with a diagnosis of intracranial hypertension. Acinetobacter spp. was detected in the cerebrospinal fluid (CSF); it was sensitive to tobramycin, ampicillin/sulbactam, and colistin. Based on the culture report, multiple daily-dose therapy with tobramycin was started. As the infectious symptoms remained, once-daily therapy was recommended; the optimal dose was calculated with nonlinear regression by least-squares analysis and a Bayesian method, using plasma and CSF samples. The infection was resolved, tobramycin therapy was discontinued, and the patient was discharged from the intensive care unit. DISCUSSION: We use once-daily intravenous tobramycin therapy because, although the intrathecal administration of drugs is generally well tolerated, the presence of preservatives may be a source of central nervous system adverse effects. Pharmacokinetic parameters were calculated with plasma and CSF concentration values obtained during the first once-daily dose by using a compartment-effect model which allows fitting of simultaneous plasma and CSF concentrations. The prediction level was determined by the estimation of drug concentrations during the fourth once-daily dose. CSF concentrations of drug were enough to eradicate the clinical signs of infection. CONCLUSIONS: Therapy using once-daily intravenous administration of tobramycin may be an adequate alternative for acinetobacter infections in neurosurgical patients when an intrathecal route is initially not recommended. The development of a compartment-effect model can be useful to predict drug concentrations.

Acinetobacter Infections↗
PubMed2006

High prevalence of ceftazidime-resistant Klebsiella pneumoniae and increase of imipenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. in Korea: a KONSAR program in 2004.

A nationwide antimicrobial resistance surveillance has been conducted since 1997 in Korea. In this study, susceptibility test data generated in 2004 by KONSAR group hospitals were analyzed and compared to those at a commercial laboratory. In hospitals, the rank orders of organisms in 2004 were identical to those in 2003. The most prevalent species was Staphylococcus aureus (20.2%) in hospitals, but Escherichia coli (29.7%) in the commercial laboratory. The proportions of Enterococcus faecium to all isolates of Enterococcus faecalis plus E. faecium were 47.2% in hospitals and 24.9% in the commercial laboratory. The mean resistance rates of significant antimicrobial-organism combinations in hospitals were: oxacillin-resistant S. aureus (68%), oxacillin-resistant (penicillin- nonsusceptible) Streptococcus pneumoniae (68%), vancomycin-resistant E. faecium (25%), cefotaxime-resistant E. coli (14%), ceftazidime- and cefoxitin-resistant Klebsiella pneumoniae (34% and 32%, respectively), and imipenem-resistant Acinetobacter spp. and Pseudomonas aeruginosa (17% and 24%, respectively). In conclusion, oxacillin-resistant staphylococci, expanded-spectrum cephalosporin-resistant K. pneumoniae, and imipenem-resistant Acinetobacter spp. and P. aeruginosa were prevalent in 2004. Increasing trends were observed for vancomycin-resistant E. faecium, cefoxitin- resistant E. coli and K. pneumoniae, and imipenem-resistant Acinetobacter spp. and P. aeruginosa. Certain antimicrobial- organism combinations were also prevalent among the commercial laboratory-tested strains.

Acinetobacter↗
PubMed2001

Structural and serological characterisation of the O-antigenic polysaccharide of the lipopolysaccharide from Acinetobacter strain 96 (DNA group 11).

A polysaccharide containing D-Manp, L-Fucp (6-deoxygalactopyranose, fucose) and D-GlcpNAc was isolated by mild acid hydrolysis, followed by gel-permeation chromatography, from the lipopolysaccharide derived from Acinetobacter strain 96 (DNA group 11). The structure of the O-antigen was determined by compositional analysis and NMR spectroscopy of the polysaccharide as: [carbohydrate structure see text] A monoclonal antibody obtained after immunization of mice with heat-killed bacteria of Acinetobacter strain 96 was shown to bind to the O-antigen and did not cross-react with any Acinetobacter O-antigen of known structure.

Acinetobacter↗
PubMed2002

Quantifying the impact of wastewater micronutrient composition on in situ growth activity of Acinetobacter spp.

Batch growth studies with pure cultures of Acinetobacter johnsoniiT and Acinetobacter johnsonii strain 210 on various media formulations were used to examine the effects of micronutrient composition on the growth rate of microbial populations in wastewater treatment systems. On nutrient rich Luria-Bertani medium, both strains of A. johnsonii grew with a doubling time of approximately 30 min. On a defined, minimal medium with acetate as the sole carbon source, the doubling time of A. johnsoniiT was 9.62 h and the doubling time of strain 210a was 2.6 h. Using a synthetic wastewater as a growth medium, the type strain had a doubling time of 56 h and strain 210a had a doubling time of 9.62 h. The concentration and redox state of iron appeared to be the principle growth limiting factors with higher doubling times occurring in media containing ferric iron as compared to ferrous iron. Additionally, grab samples from batch growth experiments were analyzed with oligonucleotide hybridization probes targeting the mature 16S ribosomal RNA (rRNA) and precursor 16S rRNA of Acinetobacter spp. Results showed that the precursor 16S rRNA levels responded more rapidly and to a greater extent than total 16S rRNA levels to changes in the micronutrient composition of the growth media. Precursor 16S rRNA levels increased in both strains when overnight cultures were diluted with fresh media and when micronutrient supplements were added to growing cultures. Our results show that the micronutrient composition of the influent wastewater can have a significant impact on the microbial community structure in wastewater treatment systems.

Acinetobacter↗
PubMedDate not supplied

[Regulation of acetate metabolism in a strain of Acinetobacter sp., growing on ethanol].

Ethanol metabolism in Acinetobacter sp. is limited by the rate of acetate assimilation in a reaction catalyzed by acetyl-CoA synthetase (EC 6.2.1.1). Effects of ions (sodium, potassium, and magnesium), byproducts of ethanol and acetaldehyde oxidation (NADH and NADPH), and pantothenic acid on this enzyme have been studied (sodium, NADH, and NADPH inhibit acetyl-CoA synthetase; pantothenic acid, potassium, and magnesium act as the enzyme activators). Conditions of culturing were developed, under which ethanol, acetaldehyde, and acetate in Acinetobacter cells were oxidized at the same rates, producing a threefold increase in the activity of acetyl-CoA synthetase in the cell-free extract. The results of studies of acetyl-CoA synthetase regulation in a mutant strain of Acinetobacter sp., which is incapable of forming exopolysaccharides, provide a basis for refining the technology of ethapolan production, involving the use of C2 substrates.

Acetaldehyde↗
PubMed2003

[Characteristics of strains of Acinetobacter spp. after culture in various media].

Growth, surface properties, production of lipase, histamine and some signal molecules (N-acyl-homoserine lactones, AHLs) in four Acinetobacter baumannii strains, in one Acinetobacter lwoffii and in one Acinetobacter haemolyticus strain cultivated in three complex media were studied. More intensive growth of bacterial suspensions was observed in Mueller-Hinton broth and in brain heart infusion in comparison with growth in proteose peptone. Greater growth of bacterial strains (with the exception of A. haemolyticus) in these two media was associated with more significant surface hydrophobicity of bacteria manifested by their adherence to xylene. A higher level of lipase was found in all strains (with the exception of A. haemolyticus) after cultivation in Mueller-Hinton broth. Composition of culture medium did not affect production of histamine. None of the studied strains in any medium tested produced short-chained unsubstituted AHLs that can be ones of the signal molecules shared with cell-to-cell communication.

Acinetobacter↗
PubMed2004

PER-1 type beta-lactamase production in Acinetobacter baumannii is related to cell adhesion.

BACKGROUND: Recently, the dissemination of ESBL (PER-1) among Acinetobacter isolates was reported in Turkish hospitals. We investigated the presence and the association of various virulence determinants in 20 Acinetobacter baumannii isolates, of which 13 were blaPER-1 positive. MATERIAL/METHODS: Virulence tests were slime and hemolysin production, gelatinase and protease activity, biofilm formation, and Caco2 cell adhesion. RAPD analysis was also performed with ERIC primers. RESULTS: None of the strains was positive for slime or hemolysin production and gelatinase or protease activity. A total of 16 strains, five of which were PER-1 gene negative, formed a biofilm on polymer surfaces. There was no relation between the presence of the PER gene and biofilm formation. On the other hand, nine strains (all PER-1 gene positive) were positive in adhesion experiments to Caco2 cell lines. All PER-negative strains were negative for cell adhesion. CONCLUSIONS: This study indicates the existence of a relation between PER-1 gene and cell adhesion in Acinetobacter strains.

Acinetobacter baumannii↗
PubMedDate not supplied

[Spread of bacteria of the genus Acinetobacter in the hydrobios of the Bay of Peter the Great, the Sea of Japan].

The analysis of the spread of bacteria of the genus Acinetobacter among the invertebrate animals of the Bay of Peter the Great (the Sea of Japan): in bivalved mollusks, sea cucumbers and sea urchins Acinetobacter bacteria were detected more often than in cushion stars and crustaceous animals. The biological properties of 45 isolated bacteria were studied with the use of a wide variety of tests. The study revealed that 9% of Acinetobacter cultures isolated from marine animals had pronounced beta-hemolysis.

Acinetobacter↗
PubMed2004

[Adhesion of Acinetobacter spp. to para-xylene].

Hydrophobicity of 200 of Acinetobacter spp. strains was defined by the BATH (Bacterial Adhesion to Hydrocarbon Test) method of Rosenberg et al. 48.0% strains of Acinetobacter spp. adhered to para-xylene. 40.0% of strains showed waek hydrophobicity, 7.5% moderate and one strain strongly adhered to para-xylene. A. baumannii strains adhered in 52.2%, A. junii in 42.1% and 20.0% in A. haemolyticus. Significantly we find weak adhesion to para-xylene than mild and strong. Mostly adhesion was discovered in A. baumannii and A. junii than in A. haemolyticus. Results show that Acinetobacter spp. has adhesive properties to para-xylene.

Acinetobacter↗
PubMed1991

[Presence of various Acinetobacter species in urinary tract infections].

Species classification of 39 strains of Acinetobacter isolated from urinary tract infections (UTI) was performed by API 20NE tests. On the whole 24 biotypes were differentiated which formed 4 species and one biotype had no defined species classification. Acinetobacter baumani was most numerously represented. Seventy seven percent of strains were isolated from urine samples from women. About 90% of Acinetobacter strains were isolated as single pathogens. Sensitivity of these strains to 23 antibiotics and chemotherapeutics using ATB-UR and disc diffusion technique was evaluated. Of all cephalosporins tested ceftazidime was the most active. All strains tested were sensitive to imepenem. The high percentage of strains was sensitive to quinolones of IIIrd generation. The high percentage of strains was resistant to nitrofurantoin.

Acinetobacter↗
PubMed1990

[Epidemiology of Acinetobacter and resistance to antibiotics at hospitals. A 5-year evaluation].

The growing number of Acinetobacter strains in hospitals and the rapid increase of their resistance to antibiotics have prompted us to undertake a long-term epidemiological study of this resistance at the Bichat hospital, Paris. Between 1971 and 1984, the resistance of Acinetobacter to antibiotics had already progressed, with only some antibiotics (imipenem, ceftazidime, tobramycin and amikacin) remaining active. During the following 5 years (1984-1988) a study of 1056 strains demonstrated a further increase of resistance and showed how serious the problem was in intensive care units. During the last few years, there has been a considerable increase in the proportion of multiresistant strains, reaching 84 per cent with beta-lactam antibiotics and 64 per cent with aminoglycosides. At present, in most cases the only effective treatment is imipenem, and no antibiotic is active in 5.5 per cent of the cases. Studies of lysotypes, enzymes and phenotypic resistance of bacterial strains completed the epidemiological approach, showing the presence of dominant lysotypes. Two predominant lysotypes are associated with multiresistance of Acinetobacter strains responsible for nosocomial infections.

Acinetobacter Infections↗