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PubMed2005

Multidrug-resistant Acinetobacter extremity infections in soldiers.

War wound infection and osteomyelitis caused by multidrug-resistant (MDR) Acinetobacter species have been prevalent during the 2003-2005 military operations in Iraq. Twenty-three soldiers wounded in Iraq and subsequently admitted to our facility from March 2003 to May 2004 had wound cultures positive for Acinetobacter calcoaceticus-baumannii complex. Eighteen had osteomyelitis, 2 burn infection, and 3 deep wound infection. Primary therapy for these infections was directed antimicrobial agents for an average of 6 weeks. All soldiers initially improved, regardless of the specific type of therapy. Patients were followed up to 23 months after completing therapy, and none had recurrent infection with Acinetobacter species. Despite the drug resistance that infecting organisms demonstrated in this series, a regimen of carefully selected extended antimicrobial-drug therapy appears effective for osteomyelitis caused by MDR Acinetobacter spp.

Acinetobacter↗
PubMed2006

Further increase of vancomycin-resistant Enterococcus faecium, amikacin- and fluoroquinolone-resistant Klebsiella pneumoniae, and imipenem-resistant Acinetobacter spp. in Korea: 2003 KONSAR surveillance.

Monitoring temporal trends of antimicrobial resistance can provide useful information for the empirical selection of antimicrobial agents to treat infected patients and for the control of nosocomial infections. In this study, we analyzed antimicrobial resistance of clinically relevant bacteria in 2003 at Korean hospitals and at a commercial laboratory. The following organism-antimicrobial agent resistance combinations were very prevalent: oxacillin-resistant Staphylococcus aureus (68%), expanded-spectrum cephalosporin-resistant Klebsiella pneumoniae (25%), and fluoroquinolone-resistant Escherichia coli (33%), Acinetobacter spp. (58%), and Pseudomonas aeruginosa (40%). Moreover, gradual increases in vancomycin-resistant Enterococcus faecium (20%), cefoxitin-resistant E. coli (10%) and K. pneumoniae (23%), and imipenem-resistant P. aeruginosa (20%) and Acinetobacter spp. (13%) were also observed. The resistance rates of Acinetobacter spp. to most antimicrobial agents at hospitals and at the commercial laboratory were similar. Among the Acinetobacter spp. isolated at a tertiary-care hospital, 46.2% were multidrug-resistant to 9-12 of 13 antimicrobial agents, and 18.3% were panresistant. The exclusion of duplicate isolates at a tertiary-care hospital significantly lowered the proportion of oxacillin-resistant S. aureus, vancomycin-resistant E. faecium, and fluoroquinolone-resistant E. coli.

Acinetobacter↗
PubMed1999

Characteristics of Acinetobacter strains (phenotype classification, antibiotic susceptibility and production of beta-lactamases) isolated from haemocultures from patients at the Teaching Hospital in Olomouc.

A total of 85 strains of the genus Acinetobacter were isolated from haemocultures at the Institute of Microbiology of the Teaching Hospital in Olomouc over the period January 1993 to June 1997. Sixty-two (73.0%) strains of the Acinetobacter calcoaceticus-baumannii complex (Acb complex) were the most frequent. In 3 (3.5%) strains it was impossible to decide whether they belonged to the Acb complex. Other acinetobacter species were represented by 20 (23.5%) strains. The greatest amount (28.2%) of these strains was collected from the Clinic of Internal Medicine. Leukemias, lymphomas and myelodysplastic syndromes were the most frequent clinical diagnoses (20.0%) of the patients with a positive haemoculture. The most effective antimicrobial preparations tested were as follows: meropenem (98.8% of susceptible strains), colistin (94.1%), quinolones (90.6-94.1% according to the type of agent) and amikacin (91.8%). The Acb complex strains were less susceptible to antimicrobial agents than other acinetobacters. Production of inductive chromosomal beta-lactamases AmpC was proved in 42 (49.4%) strains whilst no occurrence of extended-spectrum beta-lactamases (ESBL) in the isolated organisms was recorded.

Acinetobacter↗
PubMedDate not supplied

Cerebrospinal meningitis with the presence of Acinetobacter spp.

The study was conducted on 16 strains of Acinetobacter sp. which were isolated from cerebrospinal fluid. The diagnostic material was analysed with the use of automatic BacT/Alert system (Organon Teknika). The analysis was performed in the Department of Microbiology, Medical University in Bydgoszcz. API 20NE system (bioMérieux) enabled the identification of 14 strains (87.5%) as A. baumannii, 1 strain as A. haemolyticus and 1 strain as A. lwoffii. The micro-organisms were isolated from patients whose age ranged between 4 and 66 years. These patients were treated in the departments of Neurosurgery (75.0%), Neurology (18.8%) and Intensive Therapy (6.2%). The infection of cerebrospinal fluid was caused by injury and subsequent exposure to the bacteria present in external environment. Antibiotic-sensitivity of these micro-organisms was evaluated with the help of disc-diffusion method, observing standardisation conditions outlined by NCCLS. All the strains proved sensitive to carbapenems, 15 strains were sensitive to netilmicin, 7 strains--to tobramycin and 7 strains--to amikacin. All the strains displayed multiple resistance. The only exception was A. haemolyticus. The use of two-discs allowed for the detection of ESBLs in 7 A. baumannii strains. Positive results were most frequently obtained after the combination of sublactam and aztreonam. Due to microscopic resemblance between Acinetobacter spp., and bacteria of Neisseria, Moraxella and Haemophilus genus, microbiological diagnostics should not be restricted to microscopic assessment of cerebrospinal fluid and quick serological tests evaluating the antigens of the most frequent aetiological factors. Considering multiple resistance of Acinetobacter spp. to antibiotics, the treatment should be based on sensitivity tests and the ability of a given antibiotic to penetrate into cerebrospinal fluid. In our opinion, both reasonable antibiotic policy as well as observing the principles of hygiene and monitoring infections play equally important roles in the prevention of infections with Acinetobacter spp. Such combined measures may help to prevent the spreading of multiple resistant strains in hospital environment.

Acinetobacter↗
PubMed2002

[Acinetobacter, a nosocomial pathogen. Contribution of experimental models].

EPIDEMIOLOGY: The increasing importance of Acinetobacter as a nosocomial pathogen responsible for outbreaks in intensive care units has been pointed out for twenty years. Today Acinetobacter infections are essentially pneumonia in patients under mechanical ventilation. EXPERIMENTAL MODELS: Most clinical isolates are resistant to b-lactam antibiotics as well as to other drugs. Animal models represent an essential step between in vivo testing an<d clinical studies, necessary to understand physiopathology, pharmacology and efficacy of therapy. The virulence of clinical isolates of Acinetobacter spp has been studied in a mouse model of systemic infection. Pharmacological studies and efficacy of antibiotics have been studied in a mouse model of Acinetobacter pneumonia. HUMAN THERAPEUTICS: The majority of strains are multi-resistant to antibiotics and the infections they cause are difficult to treat. Isolated or combined Sulbactam has often been used with success.

Acinetobacter↗
PubMed1992

[The pathogenicity factors of bacteria in the genus Acinetobacter].

Eighty Acinetobacter strains, isolated in Togliatti from patients with purulent inflammatory diseases, were studied to determine their pathogenicity factors. Out of these 80 strains, 32.5% were found to have enterotoxigenic activity and 46.2%, adhesive activity. They were related to adhesins of the human type and to adhesins of the sheep, rabbit, swine and guinea pig types. But the most important phenomenon established in this study was the combination of different pathogenicity factors detected in Acinetobacter bacteria. Analysis of the combination of pathogenicity factors revealed that 7.5% of Acinetobacter strains had adhesive and enterotoxigenic activity, 15.3% of these strains combined adhesive and hemolytic activity and 1.2% of them were found to be enterotoxigenic and hemolytic. Only 5.0% of Acinetobacter strains were found to carry all there pathogenicity factors simultaneously.

Acinetobacter↗
PubMed2004

[A prospective study on the risk factors of Acinetobacter banmannii bacteremia infection in incubated patients with nosocomial pneumonia].

OBJECTIVE: To study the epidemiology of Acinetobacter baumannii infection in patients with ventilator-associated pneumonia (VAP). METHODS: Prospective clinical study was carried out with 176 episodes of VAP with etiologic diagnosis being followed in two groups. RESULTS: Twenty-six episodes were caused by Acinetobacter baumannii and one hundred-fifty episodes were caused by "other" organisms. Using logistic regression analysis, the risk of VAP due to Acinetobacter baumannii was found to be high in patients with head trauma [odds ratio (OR) = 4.20, 95% confidence interva (CI): 2.72 to 6.48], surgery (OR = 2.88, 95% CI: 1.78 to 4.66), acute respiratory dispnea syndrome (OR = 2.81, 95% CI: 1.19 to 6.64), and large-volume pulmonary aspiration (OR = 6.71, 95% CI: 3.91 to 11.50). CONCLUSIONS: Acinetobacter baumannii pulmonary infection in incubated patients had an epidemiological pattern that different from "other" organisms. Patients with high risk identified in our study might mark the existence of cross-infection during airway manipulation.

Acinetobacter↗
PubMed1986

[Comparative activity in vitro of ceftizoxime, ceftazidime and imipenem against Acinetobacter calcoaceticus].

Acinetobacter calcoaceticus, a nosocomial pathogenic agent, is isolated with increasing frequency from hospitalized patients. Acinetobacter is one of the most resistant pathogens to currently available antibiotics, particularly beta-lactam antibiotics. Beta-lactamases (TEM penicillinase and cephalosporinase) and problems of permeability are the most frequent mechanisms of resistance. The authors compared the in vitro activity of ceftizoxim, ceftazidim and imipenem against 82 clinical isolates of Acinetobacter calcoaceticus. Ceftizoxim, structurally similar to cefotaxim, was highly active in vitro; MIC 50%, 90% and geometric mean were respectively 6.28, 15 and 6.9 micrograms/ml. A significant difference was observed between the anitratum and lwoffi varieties. The lwoffi variety was more susceptible to tested drugs than the anitratum variety. Ceftazidim activity was comparable with MIC 50 of 6.5 micrograms/ml and MIC 90 of 26.2 micrograms/ml. A good bactericidal activity was observed against susceptible strains (MIC less than or equal to 4 micrograms/ml). Imipenem showed the greatest activity since 0.47 microgram/ml of the drug inhibited 90% of Acinetobacter calcoaceticus.

Acinetobacter↗
PubMed1987

[Ecology and the antibiotic sensitivity of hospital strains of Acinetobacter].

Strains of Acinetobacter were shown to be widely distributed in the environment of traumatological and orthopedic hospitals and in clinical pathological materials. This permitted to consider Acinetobacter as an agent causing hospital infections. It was shown that Acinetobacter strains were resistant to the majority of antibacterial drugs. The potential ability of Acinetobacter to transfer resistance plasmids to other strains is of particular danger for distribution of resistant microorganisms in hospitals.

Acinetobacter↗
PubMed1983

[Comparative in vitro activity of 6 recent beta-lactams against hospital strains of Acinetobacter calcoaceticus: role of the monobactam SQ 26,776].

Acinetobacter calcoaceticus is recognized as one of the most resistant nosocomial pathogens. Clinical isolates of Acinetobacter are usually resistant to most beta-lactam antibiotics and even to carbenicillin; 50% of the strains isolated in 1981-82 at the Bichat hospital were inhibited only at a concentration of 180 micrograms/ml. Recently several new molecules belonging to the beta-lactam group were discovered. Among them, monobactam SQ 26 776, a new broad spectrum highly potent monocyclic beta-lactam antibiotic, is resistant to beta-lactamase degradation and is able to inhibit especially Pseudomonas aeruginosa and Providencia. Its activity against 110 clinical strains of Acinetobacter was compared to that of 5 recent beta-lactam antibiotics which are resistant to beta-lactamase degradation (N-formimidoyl-thienamycin, cefotaxime, moxalactam, ceftriaxone, cefoperazone). 50% of the strains were inhibited at a concentration of 25 micrograms/ml and 90% at a concentration of 58 micrograms/ml of monobactam. The geometric mean was 27 micrograms/ml. For the other beta-lactam antibiotics, the MIC values (except for thienamycin), were superior to the critical values of bacterial susceptibility. N-formimidoyl-thienamycin is the most active compound against clinical isolates of Acinetobacter, with MIC 50 and MIC 90% being respectively of 0,4 and 0,8 micrograms/ml.

Acinetobacter↗
PubMed1995

[Biological characteristics and antibiotic sensitivity of Acinetobacter strains].

Fifty Acinetobacter strains were investigated. Their differentiation according to the species position showed that 30 strains belonged to A. calcoaceticus and 20 strains belonged to A. lwoffi. It was found that the Acinetobacter strains had multiple drug resistance. They showed 100 per cent resistance to ampicillin, carbenicillin, erythromycin, methicillin, oxacillin, tetracycline, oleandomycin, streptomycin, rondomycin and lincomycin. According to the results of the study the most efficient antibiotics were cefazolin, cefotaxime, ceftazidime and polymyxin. The Acinetobacter hospital strains contained conjugative plasmids of different incompatibility groups. 50 per cent of the Acinetobacter strains contained conjugative R plasmids determining the resistance to streptomycin, kanamycin and tetracycline and referring to the T, J, M and N incompatibility groups. Their molecular weights were 42.0, 35.0, 30.0 and 50.0 MD respectively.

Acinetobacter↗
PubMed2025

Growth inhibition of Acinetobacter by 5-chloro-indole-3-acetic acid.

The Acinetobacter calcoaceticus-baumannii complex includes high-priority, multidrug-resistant pathogens for which novel antibiotics are urgently needed. Many bacterial strains from this complex harbor a so-called iac gene cluster that codes for the catabolism of indole-3-acetic acid (IAA). Here, we demonstrate that possession and expression of iac genes represent an Achilles' heel for Acinetobacter species, which can be exploited to suppress bacterial growth by treatment with IAA and its analog 5-chloro-IAA.IMPORTANCEAcinetobacter baumannii is a deadly bacterial pathogen and one of the leading causes of hospital-acquired infections worldwide. It is also known for its resistance to many antibiotics currently available. In this study, we show that Acinetobacter bacteria choke on a mixture of IAA and 5-chloro-IAA, offering a path to the discovery and development of a novel drug treatment.

Indoleacetic Acids↗
PubMed1989

Influence of environmental parameters on polyphosphate accumulation in Acinetobacter sp.

The regulation of and the optimum conditions for polyphosphate accumulation in Acinetobacter sp. were determined. Acinetobacter strain 210A accumulated polyphosphate in the presence of an intra- or extracellular energy source. The accumulation of polyphosphate during endogenous respiration was stimulated by streptomycin and inhibited by KCN. The highest amount of polyphosphate was found in cells in which energy supply was not limited, namely at low growth rates under sulphur limitation, and in the stationary phase of growth when either the nitrogen or the sulphur source was depleted. The phosphorus accumulation was not affected by the pH between 6.5 and 9. There was a pronounced effect of the temperature on phosphorus accumulation but is varied from strain to strain. Acinetobacter strain 210A accumulated more phosphate at low temperatures, strain B8 showed an optimum accumulation at 27.5 degrees C, while strain P accumulated phosphorus independently of the temperature. The optimum temperature for growth of Acinetobacter strains tested ranged from 25 to 33 degrees C, and the optimum pH was between 6 and 9.

Acinetobacter↗
PubMed2006

Air ionisation and colonisation/infection with methicillin-resistant Staphylococcus aureus and Acinetobacter species in an intensive care unit.

OBJECTIVE: To determine effect of negative air ions on colonisation/infection with methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter species in an intensive care unit. DESIGN: Prospective single-centre cross-over study in an adult general intensive care unit. PATIENTS: 201 patients whose stay on the unit exceeded 48 hour's duration. INTERVENTION: Six negative air ionisers were installed on the unit but not operational for the first 5 months of the study (control period). Devices were then operational for the following 5.5 months. MEASUREMENTS AND RESULTS: 30 and 13 patients were colonised/infected with MRSA and Acinetobacter spp., respectively, over 10.5 months. No change in MRSA colonisation/infection was observed compared with the 5 month control period. Acinetobacter cases were reduced from 11 to 2 (p=0.007). CONCLUSION: Ionisers may have a role in the prevention of Acinetobacter infections.

Acinetobacter Infections↗
PubMed2002

Evaluation of non-cyanobacterial genome sequences for occurrence of genes encoding proteins homologous to cyanophycin synthetase and cloning of an active cyanophycin synthetase from Acinetobacter sp. strain DSM 587.

All publicly accessible microbial genome databases were searched for the occurrence of genes encoding proteins homologous to the cyanophycin synthetase (CphA) of Synechocystis sp. strain PCC 6803 in order to reveal the capability of microorganisms not belonging to the cyanobacteria to synthesize cyanophycin. Among 65 genome sequences, genes homologous to cphA were found in Acinetobacter sp. strain ADP1 (encoding a protein homologous to CphA with 40% amino acid identity), Bordetella bronchiseptica strain RB50 (39%), Bordetella pertussis strain Tohama I (39%), Bordetella parapertussis strain 12822 (39%), Clostridium botulinum strain ATCC 3502 (39%), Desulfitobacterium hafniense strain DCB-2 (38%) and Nitrosomonas europaea strain ATCC 25978 (37%). The gene homologous to cphA from Acinetobacter sp. strain DSM 587 was amplified by PCR, ligated to the vector pBluescript SK(-) downstream of the lac promoter and introduced into Escherichia coli. The recombinant strain of E. coli expressed CphA activity at up to 1.2 U/mg protein and accumulated cyanophycin to up to 7.5% of the cellular dry matter, indicating that CphA of Acinetobacter sp. strain DSM 587 is functionally active. In Acinetobacter sp. strain DSM 587 itself, cyanophycin accumulated to up to 1.4% of the total protein under phosphate-limited conditions, and cyanophycin synthetase activity was detected, which indicated the function of cyanophycin as a storage compound in this strain.

Acinetobacter↗
PubMed2002

Opportunistic colonization of Ralstonia solanacearum-infected plants by Acinetobacter sp. and its natural competence development.

The behavior of the soil bacterium Acinetobacter sp. BD413 was monitored in Ralstonia solanacearum-infected and non-infected tomato plants after direct injection into the stem or natural infection by roots. In healthy plants, Acinetobacter sp. BD413 failed to colonize plant tissue. In plants infected simultaneously by the pathogen R. solanacearum,the Acinetobacter population increased linearly to about 3.1 x 10(7) cells per gram plant material and was maintained at a high level until the death of the plant. Moreover, Acinetobacter sp. BD413 was found to develop a competent state when multiplying in planta, indicating it could possibly be transformed by bacterial or plant DNA.

Acinetobacter↗
PubMed2003

Multidrug resistant Acinetobacter baumannii isolates from a teaching hospital.

Abstract Acinetobacter baumannii is the most common nosocomial pathogen among all Acinetobacter spp. A. baumannii tend to be resistant to multiple antibiotics, and represent a severe threat in the treatment of hospitalized patients. The purpose of this study was to evaluate the prevalence, biotyping, and antibiotic resistance status of A. baumannii isolates recovered from submitted hospital clinical specimens. The in-vitro activity of 29 currently used antimicrobial agents was studied in 180 isolates of A. baumannii. The prevalence was higher in wound exudates (32%) and urine samples (22%) than in other specimens. Forty-six percent of the isolates were of biotype 9. The evolution of resistance from November 1996 through October 1998 was studied. More than 75% of the isolates were multidrug resistant (MDR) and more than 70% were #-lactamase producers. Amikacin, ampicillin + sulbactam, and imipenem are still effective antimicrobial agents, but a steady rise in the values of the minimum inhibitory concentration at which 50% of the isolates were inhibited (MIC50 )and MIC90 was observed. Resistance to aztreonam (60%), enrofloxacin (60%), imipenem (29%), moxalactam (73%), and sparfloxacin (25%) was noted; enrofloxacin and sparfloxacin are not generally used in this hospital. From the findings of the present study, no single drug appears to be suitable for empirical therapy for this nosocomial pathogen. Abstract Acinetobacter baumannii is the most common nosocomial pathogen among all Acinetobacter spp. A. baumannii tend to be resistant to multiple antibiotics, and represent a severe threat in the treatment of hospitalized patients. The purpose of this study was to evaluate the prevalence, biotyping, and antibiotic resistance status of A. baumannii isolates recovered from submitted hospital clinical specimens. The in-vitro activity of 29 currently used antimicrobial agents was studied in 180 isolates of A. baumannii. The prevalence was higher in wound exudates (32%) and urine samples (22%) than in other specimens. Forty-six percent of the isolates were of biotype 9. The evolution of resistance from November 1996 through October 1998 was studied. More than 75% of the isolates were multidrug resistant (MDR) and more than 70% were #-lactamase producers. Amikacin, ampicillin + sulbactam, and imipenem are still effective antimicrobial agents, but a steady rise in the values of the minimum inhibitory concentration at which 50% of the isolates were inhibited (MIC50) and MIC90 was observed. Resistance to aztreonam (60%), enrofloxacin (60%), imipenem (29%), moxalactam (73%), and sparfloxacin (25%) was noted; enrofloxacin and sparfloxacin are not generally used in this hospital. From the findings of the present study, no single drug appears to be suitable for empirical therapy for this nosocomial pathogen.

Acinetobacter baumannii↗
PubMed2007

Evaluation of biosorption potency of Acinetobacter sp. for removal of hexavalent chromium from tannery effluent.

Two bacterial consortia were developed by continuous enrichment of microbial population of tannery and pulp and paper mill effluent contained Serratia mercascens, Pseudomonas fluorescence, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter sp. identified by 16S rDNA method. The consortia evaluated for removal of chromate [(Cr(VI)] in shake flask culture indicated pulp and paper mill consortium had more potential for removal of chromate. Acinetobacter sp. isolated from pulp and paper mill consortium removed higher amount of chromate [Cr(VI)] under aerobic conditions. Parameters optimized in different carbon, nitrogen sources, and pH, indicated maximum removal of chromate in sodium acetate (0.2%), sodium nitrate (0.1%) and pH 7 by Acinetobacter sp. Bacteria was applied in 2-l bioreactor significantly removed chromate after 3 days. The results of the study indicated removal of more than 75% chromium by Acinetobacter sp. determined by diphenylcarbazide colorimetric assay and atomic absorption spectrophotometer after 7 days. Study of microbial [Cr(VI)] removal and identification of reduction intermediates has been hindered by the lack of analytical techniques. Therefore, removal of chromium was further substantiated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) which indicated bioaccumulation of chromium in the bacterial cells.

Acinetobacter↗