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PubMed2001

Successful treatment of late onset infection due to multi-drug resistant Acinetobacter Lwoffii in a low birth weight neonate using ciprofloxacin.

This report presents the case of a low birth weight neonate with multidrug-resistant Acinetobacter Lwoffii infection who was successfully treated with ciprofloxacin and co-trimoxazole. Use of ciprofloxacin in pediatric populations was reviewed. The infant responded to the antibiotic regimen with sterilized cerebrospinal fluid with no adverse effects attributable to the ciprofloxacin. Although ciprofloxacin has been found to cause irreversible damage to cartilage in laboratory animals, a review of the literature found that this complication rarely occurs in pediatric patients. Ciprofloxacin has been found to be effective in the treatment of multidrug-resistant gram negative infections in pediatric patients, including premature infants. Ciprofloxacin should be considered in the treatment of neonatal infection caused by multidrug-resistant gram-negative organisms.

Acinetobacter↗
PubMed2001

In vitro activity of CA(1-8)M(1-18), a synthetic cecropin A-melittin hybrid peptide, against multiresistant Acinetobacter baumannii strains.

The in vitro antibiotic activity of CA(1-8)M(1-18), a synthetic cecropin A-melittin hybrid peptide, was determined by broth microdilution on 20 clinical Acinetobacter baumannii isolates with different resistance profiles. The MIC(50), MIC(90) and ranges were 4 mg/l, 4 mg/l and 2-8 mg/l, respectively, and were independent of resistance pattern. Different assay parameters such as microplate plastic (polystyrene or polypropylene), addition of supplements (5-10% fetal calf serum or 5% horse blood), inoculum size (10(5), 10(6), 10(7) and 10(8) CFU/ml) or incubation period (24 or 48 h) were studied. MIC was independent of the first two parameters, although the MIC values increased both with inoculum size or incubation period. Killing curves were obtained both for a standard strain and a multiresistant isolate over a 45.7-2.8 mg/l (16-1 mM) peptide range, using an initial inoculum of 10(5)-10(6) CFU/ml and 10(9)-10(10) CFU/ml. A concentration of 45.7 mg/l was required for complete killing. Accordingly, CA(1-8)M(1-18) showed good in vitro activity against the A. baumannii strains tested irrespective of the resistance to classical antibiotics, and could be a future candidate for multiresistant A. baumannii infections, although further cytotoxicity and pharmacological studies will be needed.

Acinetobacter↗
PubMed2001

[Activity of new fluoroquinolones against clinical isolates of Acinetobacter baumannii].

Acinetobacter baumannii is an opportunistic pathogen associated with numerous nosocomial infections. In recent years it has shown extraordinary ease in developing resistance to most antimicrobial agents, which is a serious problem as it makes these infections difficult to treat. We determined the in vitro activity of eight quinolones, five betalactam agents and colistin in 160 clinical isolates of A. baumannii. In general, we observed a high rate of resistance to the quinolones (90%), excluding clinafloxacin (25%), and to ampicillin-sulbactam (61.25%) and imipenem (50%). Colistin is the agent with least resistance (13.125%), although its toxicity limits its therapeutic use. Clinafloxacin may be a good option to treat A. baumannii infections, especially in cases of therapeutic failure with other antimicrobial agents.

Acinetobacter↗
PubMedDate not supplied

A multi-resistant Acinetobacter baumannii outbreak in a general intensive care unit.

In an Intensive Care Unit, three patients were found infected and two colonized with multiresistant Acinetobacter baumannii within a period of one week. To identify the outbreak source, two surveillance studies were performed concerning patients and the environment. Genotyping of isolates was performed by random amplification of polymorphic DNA analysis (RAPD). Environmental sampling failed to yield A. baumannii, with the exception of a single sample from a trunking. RAPD-fingerprinting yielded identical patterns for all patient isolates including the trunking isolate, thus confirming the suspected cluster. Since the strain from the trunking had a susceptibility pattern and a RAPD pattern identical to that of the strains isolated from the patients, we believe that this was the likely source of the outbreak. In conclusion, A. baumannii outbreaks may be quickly controlled by appropriate action of the hospital infection staff. RAPD-fingerprinting may provide a useful and rapid identification technique for the epidemiological investigation of a hospital outbreak.

Acinetobacter Infections↗
PubMed2003

Effects of permeabilizers on antimicrobial susceptibility of Stenotrophomonas maltophilia and Acinetobacter spp.

Isolates of the gram-negative bacteria Stenotrophomonas maltophilia and Acinetobacter spp. are naturally resistant to many classes of antibiotics. Using the disk diffusion technique it was shown that the membrane permeabilizers ethylenediaminetetraacetic acid, sodium citrate, and sodium polyphosphate increased susceptibility to a range of antibiotics including imipenem, ciprofloxacin, tetracycline, and rifampicin. These effects are probably due to the metal chelating properties of the permeabilizers.

Acinetobacter↗
PubMed2003

[In vitro activity of azithromycin against clinical isolates of Acinetobacter baumannii].

The activity of azithromycin against 225 clinical strains of Acinetobacter baumannii isolated consecutively from 26 Spanish hospitals in November 2000 was studied. The MICs of azithromycin were determined by microdilution, according to the NCCLS guidelines. The bactericidal activity of azithromycin against 15 clonally unrelated A. baumannii strains with different antimicrobial susceptibility patterns was tested using the subculture method. The killing-curves method was also performed against five strains with different susceptibility to azithromycin. The MIC(50) and MIC(90) of azithromycin were 32 and 64 mg/l, respectively. Moderate bactericidal activity was observed in 14 out of the 15 strains evaluated by the subculture method (MBCs from 1 to 4 dilution steps higher than the MICs) and by the killing-curve method. For three strains the number of CFU/ml was reduced 1 to 1.4 log by concentrations of azithromycin equivalent to 1 and 4 times their MICs. lt is concluded that azithromycin has moderate bactericidal activity against the strains of A. baumannii evaluated.

Acinetobacter Infections↗
PubMed2003

Clinical features of pandrug-resistant Acinetobacter baumannii bacteremia at a university hospital in Taiwan.

BACKGROUND AND PURPOSE: The number of infections caused by Acinetobacter baumannii has increased in recent years and the emergence of pandrug-resistant A. baumannii (PDRAB) has been observed in Taiwan. The aim of this study was to evaluate the clinical features and outcomes of patients with bacteremia due to PDRAB. METHODS: From January 1999 to April 2002, 30 patients with PDRAB bacteremia were treated. We analyzed the clinical characteristics of these patients, including gender, underlying diseases, clinical manifestations, antibiotic treatment, and outcome. RESULTS: Bacteremia developed an average of 33 days after hospitalization and was hospital acquired in all cases. The source of bacteremia was identified in 19 patients (63.3%) and was most commonly from the respiratory tract. The overall mortality was 60% (18 patients). Among these, the cause of death was directly related to PDRAB bacteremia in 12. Underlying heart disease, shock, resuscitation, acute respiratory distress syndrome, mechanical ventilation, and multiple organ dysfunction score (MODS) were significant predictors of mortality after the development of PDRAB bacteremia. No specific antimicrobial therapy appeared to be effective. CONCLUSIONS: Clinical outcomes of patients with PDRAB bacteremia were related to the medical conditions of the patients at the time of development of bacteremia and could be predicted by the MODS. The only way to limit the spread is through strict preventive measures for nosocomial infection and antibiotic control.

Acinetobacter Infections↗
PubMed2003

Community-acquired bacteremic cellulitis caused by Acinetobacter baumannii.

Acinetobacter baumannii is rarely encountered as a pathogen causing community-acquired skin and soft tissue infection. A 79-year-old man had a fever for 3 days accompanied by pain and swelling over the left leg around an old scar caused by a dog bite 10 years ago. Two sets of blood cultures and a wound culture all yielded A. baumannii. The patient's condition deteriorated initially but recovered completely after 3 weeks of meropenem treatment. This case suggests that A. baumannii should be included among pathogens with the potential to cause complicated skin infection in the community.

Acinetobacter Infections↗
PubMed2004

Evaluation of phenotypic and genotypic markers for clinical strains of Acinetobacter baumannii.

Acinetobacter baumannii is an important opportunistic pathogen that is rapidly evolving toward multidrug resistance and is involved in various nosocomial infections that are often severe. It strongly prompts the epidemiological study of A. baumannii infections. However, there is no a generally accepted typing scheme. Different genotypic and phenotypic procedures were evaluated for the characterization of clinical isolates of A. baumannii isolated from a community hospital of Rosario, Argentina (Hospital de Emergencias Clemente Alvarez, HECA), during a period of four years. These included PCR with degenerate oligonucleotide primers (DO-PCR), repetitive extragenic palindromic-PCR (REP-PCR), pulsed-field gel electrophoresis (PFGE), and antibiotyping. Amongst individual methods, DO-PCR and PFGE were found the most suitable methods to discriminate A. baumannii clinical isolates [discriminatory indexes (D) of 0.98 and 0.96, respectively]. On the other hand, both antibiotyping and REP-PCR were much less discriminatory (D: 0.86 and 0.77, respectively). The combination of antibiotyping with any of the above genotypic procedures was found to largely increase D. In particular, the combination of DO-PCR and antibiotyping provided the best discriminatory method for epidemiological studies of A. baumannii. Combination of the different genotypic and phenotypic procedures allowed the inference of genetic relationships and dissemination of multidrug-resistant A. baumannii clones in HECA in the period 1994-1999. One particular strain, which showed sensibility to carbapenems, was found widely distributed in this hospital during 1994-1996. A different strain, showing additional resistance to carbapenems, rapidly disseminated in HECA in coincidence with the introduction of imipenem therapy in 1997.

Acinetobacter Infections↗
PubMed2004

Acinetobacter baumannii infections among patients at military medical facilities treating injured U.S. service members, 2002-2004.

Acinetobacter baumannii is a well known but relatively uncommon cause of health-care--associated infections. Because the organism has developed substantial antimicrobial resistance, treatment of infections attributed to A. baumannii has become increasingly difficult This report describes an increasing number of A. baumannii bloodstream infections in patients at military medical facilities in which service members injured in the Iraq/Kuwait region during Operation Iraqi Freedom (OIF) and in Afghanistan during Operation Enduring Freedom (OEF) were treated. The number of these infections and their resistance to multiple antimicrobial agents underscore 1) the importance of infection control during treatment in combat and health-care settings and 2) the need to develop new antimicrobial drugs to treat these infections.

Acinetobacter Infections↗
PubMedDate not supplied

[Spinal epidural abscess caused by Acinetobacter baumannii mimicking a herniated lumbar disc].

INTRODUCTION: A vertebral epidural abscess usually offers a very varied clinical picture of systemic involvement with signs of infection, general malaise and neurological focus. It is diagnosed by means of magnetic resonance imaging, which reveals large lesions with frequent involvement of soft tissues and peripheral contrast enhancement. CASE REPORT: A 35-year-old male with lumbar-radicular pain in the right S1 with Lasègue's sign at 20 degrees on the right side and abolition of the Achilles' reflex. Magnetic resonance imaging showed an extradural lesion in L5-S1, dependent on the disc space, which suggested a herniated disc. The rest of the anamnesis, explorations and analyses were normal except for a slightly high erythrocyte sedimentation rate. The patient was submitted to surgery and an epidural abscess was observed from which an Acinetobacter baumanii was recovered. Treatment was established with antibiotics and a rigid lumbosacral orthosis. At three months clear signs of discitis were observed in magnetic resonance images; these were completely resolved at eight months, when the patient was asymptomatic. CONCLUSIONS: Epidural abscess must be included in the differential diagnosis of a herniated disc because in the early phases it can give rise to symptoms of lumbar-radicular pain that are identical to those caused by a herniated lumbar disc. This is the first case of an epidural abscess produced by A. baumanii.

Acinetobacter Infections↗
PubMed2005

Predictors of mortality in Acinetobacter baumannii bacteremia.

This study retrospectively investigated 149 episodes of Acinetobacter baumannii bacteremia which occurred during a 41-month period from September 1997 to January 2001. Bacteremia was nosocomial in 139 (93%) of the episodes and community-acquired in 10 (7%). Thirty three deaths (22.1%) were attributed to these episodes of A. baumannii bacteremia. The mean age of survivors was younger than that of patients who died of bacteremia (60.4 +/- 19.9 vs 67.1 +/- 17.4) but this result was not significant on univariate analysis (p=0.084). Previous intensive care unit stay was longer among survivors than among patients who died of bacteremia (9.5 vs 18 days, p=0.048). Factors associated with mortality included immunosuppression (p=0.019), shock (p=0.002), recent surgery (p=0.008), invasive procedures such as central venous catheterization (p=0.002), urinary catheterization (p=0.012), placement of a nasogastric tube (p<0.001), pulmonary catheterization (p=0.015), and mechanical ventilation (p=0.035). The number of underlying conditions (p=0.015) and invasive procedures (p<0.001) were positively correlated with mortality. Mortality was significantly associated with lower platelet count (p=0.001) and lower serum albumin concentration (p=0.005). Patients with catheter-related bacteremia had a high survival rate (96.2%), while survival rate was low in patients with infection originating from the respiratory tract (60.8%). Susceptibility testing by agar dilution test indicated that imipenem was the most effective antibiotic, followed by cefepime and ciprofloxacin. The mortality rate was lower in patients who received 1 or more antibiotics to which the isolates were susceptible, but this difference was not significant (p=0.197). On multivariate analysis, factors that independently correlated with mortality were increased age (p=0.003), immunosuppressive status (p=0.001), recent surgery (p=0.002), acute respiratory failure (p=0.004), acute renal failure (p=0.009) and septic shock (p<0.001). These findings highlight the importance of a treatment strategy based on risk stratification among patients with A. baumannii bacteremia.

Acinetobacter Infections↗
PubMed2005

Spread of a single clone Acinetobacter baumannii strain in an intensive care unit of a teaching hospital in Turkey.

Acinetobacter baumannii is an important nosocomial pathogen, especially in immunocomprimised patients and those hospitalized in intensive care units. After the first isolation of A. baumannii strains from the bronchial aspirates of two patients in the intensive care unit (ICU) of our hospital as a pure culture, screening studies were performed to define possible source(s). A. baumannii strains isolated from bronchial aspirates and blood cultures of the patients in ICU were collected as a possible part of the outbreak. A total of 23 screening samples collected from equipment (7), hands (4) and gloves (2) of the staff, and from ten different body regions of the patients in the ICU were cultured. Antimicrobial susceptibility test of the isolates was performed by the standardized disk-diffusion method. All isolates were subtyped by antibiogram, arbitrarily primed polymerase chain reaction (AP-PCR) and pulsed-field gel electrophoresis (PFGE) typing methods. A total of 26 A. baumannii strains including eight clinical and 18 screening isolates were identified. All isolates were susceptible only to meropenem, tobramycin, and imipenem. There was at least a 96% resistance rate to the other antibiotics tested. Antibiogram typing showed that 24 of the 26 isolates were epidemiologically related, two were unique. AP-PCR yielded two types, one of which had 21 isolates, the other had five. PFGE fingerprinting revealed that all isolates were clonally related, including four closely related and 22 indistinguishable strains. Based on the results of PFGE which has been accepted as a reference method it can be concluded that A. baumannii strains isolated from our intensive care unit originated from a single type of strain.

Acinetobacter Infections↗
PubMed2006

[Molecular epidemiological study of colistin-only-sensitive strains of multi-drug resistant Acinetobacter baumannii].

OBJECTIVE: To genetically analyze the epidemiology of the colistin-only-sensitive (COS) Acinetobacter baumannii (COS-AB) so as to provide experimental data for controlling COS-AB infection. METHODS: The drug resistance to 14 antibiotics of 136 COS-AB isolates collected in Ruijin Hospital from June 2004 to May 2005 were analyzed. 66 A. baumannii isolates were collected from May to December 2004, of which 33 strains were COS-AB and the other 33 non-COS-AB. Random amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) were applied to analyze the homology of these strains. RESULTS: RAPD analysis (with the primers ERIC2 and 272) showed all COS-AB strains as identical, while PFGE analysis showed that these COS-AB were of two closely related genotypes distinctly different from that of the non-COS-AB. The COS-AB strains obtained from the Burns Ward were PFGE B type causing inter-ward outbreak of single clone. And the COS-AB strains obtained from another wards were PFGE BA type causing inter-departmental outbreak, mainly among the departments of surgical system. CONCLUSION: The cross-infection of COS-AB is severe. Strict disinfection and sterilization should be implemented. The epidemiology of COS-AB in environment and patients should be closely monitored. PFGE analysis is a more accurate method in typing A. baumannii.

Acinetobacter Infections↗
PubMed2006

[Susceptibility pattern of Acinetobacter baumannii clinical isolates in Madrid vs. Hong Kong].

The objective of this study was to compare the susceptibility to seven antimicrobials of Acinetobacter baumannii clinical isolates from H. U. de La Princesa of Madrid vs. A. baumannii clinical isolates from Hospital Queen Mary of Hong Kong from January 2004 to March 2005. A total of 74 strains isolated from our hospital and 30 strains attended to Hospital Queen Mary were studied. The MIC (minimal inhibitory concentration) was determined by agar dilution method. NCCLS recommended breakpoints were used against imipenem, tobramycin, amikacin, ofloxacin and ceftazidime. For sulbactam the break point for ampicillin/sulbactam was used. BSAC breakpoint was considered against colistin. Colistin showed the highest susceptibility percentage in Spanish strains (98.64%), followed by imipenem (94.59%) and tobramycin (78.37%). About 50% of the clinical isolates were susceptible to sulbactam (54.05%) and amikacin (51.35%). The majority of the strains were resistant to ofloxacin (2.7% of susceptible strains) and ceftazidime (1.35% of susceptible strains). In the Hong Kong clinical isolates, high susceptibility percentages were shown for most antimicrobials: 96.66% to colistin, sulbactam, tobramycin and amikacin; lower for imipenem (93.33%) and ofloxacin (90%). Ceftazidime presented the lowest susceptibility percentage (10%). In conclusion, higher resistant percentages in Spanish strains than Chinese strains were obtained for most antimicrobials tested. To ofloxacin, 90% of Hong Kong isolates were susceptible while 93% of Madrid isolates were resistant. Geographically remote populations (such as Madrid and Hong Kong) showed important differences according to the susceptibility patterns.

Acinetobacter Infections↗
PubMed1991

Acinetobacter calcoaceticus bacteremia: analysis of 48 cases.

The medical records of 48 patients with Acinetobacter calcoaceticus bacteremia over a recent two-year period were reviewed retrospectively to determine the epidemiologic and clinical features. There were 34 males and 14 females with a median age of 51 years. Forty-six of the cases were hospital-acquired. The characteristics of these patients included residence in the intensive care unit, intubation and ventilatory support, preceding antibiotic therapy and intravascular catheterization. In vitro susceptibility testing for the isolated organisms revealed that 32% of these strains were resistant to gentamicin and 90% were aztreonam-resistant. Minocycline, amikacin, ceftazidime, ticarcillin, imipenem, and the new quinolones retained good activity. Although A. calcoaceticus causes septic pictures as do other aerobic Gram-negative bacilli and part of these isolates are multiple drug-resistant, the infection did not seem to be difficult to control. Twenty-six (54%) of these patients survived, including 9 patients without appropriate antimicrobial therapy initiated within 48 hours of blood sampling. The mortality was rarely due to bacteremia per se; most often, it resulted from the underlying diseases.

Acinetobacter Infections↗
PubMed2006

Outbreaks of imipenem-resistant Acinetobacter baumannii producing carbapenemases in Korea.

Among 53 Acinetobacter baumannii isolates collected in 2004, nine imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Korea. Nine carbapenemase-producing isolates were further investigated in order to determine the mechanisms underlying resistance. These isolates were then analyzed via antibiotic susceptibility testing, microbiological tests of carbapenemase activity, pI determination, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. One outbreak involved seven cases of infection by A. baumannii producing OXA-23 beta-lactamase, and was found to have been caused by a single ERIC-PCR clone. During the study period, the other outbreak involved two cases of infection by A. baumannii producing IMP-1 beta-lactamase. The two clones, one from each of the outbreaks, were characterized via a modified cloverleaf synergy test and an EDTA-disk synergy test. The isoelectric focusing of the crude bacterial extracts detected nitrocefin-positive bands with pI values of 6.65 (OXA-23) and 9.0 (IMP-1). The PCR amplification and characterization of the amplicons via direct sequencing showed that the clonal isolates harbored blaIMP-1 or blaOXA-23 determinants. The two clones were characterized by a multidrug resistance phenotype that remained unaltered throughout the outbreak. This resistance encompassed penicillins, extended-spectrum cephalosporins, carbapenems, monobactams, and aminoglycosides. These results appear to show that the imipenem resistance observed among nine Korean A. baumannii isolates could be attributed to the spread of an IMP-1- or OXA-23-producing clone. Our microbiological test of carbapenemase activity is a simple method for the screening of clinical isolates producing class D carbapenemase and/or class B metallo-beta-lactamase, in order both to determine their clinical impact and to prevent further spread.

Acinetobacter Infections↗