No abstract available.
Acinetobacter/*isolation & purification ; Acinetobacter Infections/*drug therapy/*microbiology ; Anti-Bacterial Agents/*therapeutic use ; Cross Infection/*microbiology/*therapy ; Female ; Humans ; Male ; Meningitis, Bacterial/*drug therapy/*microbiology ; Staphylococcal Infections/*drug therapy/*microbiology ; Staphylococcus/*isolation & purification

BACKGROUND: Despite increasing importance of Acinetobacter baumannii in nosocomial infections and rapid development of multi-antimicrobial resistance in this strain, the resistance mechanisms of beta-lactam antimicrobials in A. baumannii were not clearly defined. In order to observe the resistance mechanisms against beta-lactams and carbapenem, we characterized the production of beta-lactamases and outermembrane protein (OMP) profiles for the 44 clinical isolates of A. baumannii. METHODS: The MICs of antimicrobials were determined by agar dilution test. The secondary beta-lactamases were characterized by isoelectric focusing, polymerase chain reactions and nucleotide sequencing, and the production of chromosomal beta-lactamases was quantitated by spectrophotometric method. For two strains with an elevated MIC of carbapenem, outermembrane protein (OMP) profile was analyzed by ultracentrifugation of the sonicated bacteral cells and SDS-PAGE. RESULTS AND CONCLUSION: Twenty two or 4 of 44 strains produced TEM-1-like beta-lactamase or PER-1 extended-spectrum beta-lactamase, respectively. However, when we analyzed the MICs of several beta-lactams with the beta-lactamase production, the resistance level of beta-lactam was mainly determined by the production of chromosomal beta-lactamase, not by the secondary beta-lactamases in the clinical isolates of A. baumannii. In two strains with an elevated MIC of imipenem, a decrease or loss of about 35 kDa and 22 kDa proteins in OMP was observed, which suggested that the change of OMP played a role in carbapenem resistance.
Acinetobacter/*drug effects/isolation & purification/metabolism ; Acinetobacter Infections/drug therapy/microbiology ; Antibiotics, Lactam/*pharmacology ; Bacterial Outer Membrane Proteins/biosynthesis ; Carbapenems/pharmacology ; Cross Infection/drug therapy/microbiology ; Drug Resistance, Bacterial ; Human ; beta-Lactamases/biosynthesis

OBJECTIVETo analyze clinical characteristics and therapy of pan-resistant Acinetobacter baumannii (PDRAB) infection and explore the methods for effective therapy and prevention of this infection.

METHODSNine hospitalized patients with PDRAB infection confirmed by pathogen and susceptibility testing were analyzed for the risk factors and the treatment outcomes were assessed by case analysis.

RESULTSPDRAB infections occurred mainly in patients with severe complications, most of whom had complications by diabetes or hypertension or damaged mucosal integrity due to mechanical ventilation, surgery and catheterization. The polymyxin sensitivity were 100% for these infections, but all the bacteria identified showed a antimicrobial resistance rates of 100%. The majority of the infections were acquired during hospitalization occurring mainly in the lungs; all the patients had prolonged hospitalization and received antibiotic treatments with high proportions of broad-spectrum antimicrobial agents especially third-generation cephalosporins and quinolones. Exclusive or sequential use of carbapenems and sulbactam in combination with quinolone or aminoglycoside produced favorable effects.

CONCLUSIONSThe prevalence of hospital-acquired pan-resistance of PDRAB infections increased significantly in recent years, particularly in patients with high risk factors. The widespread use of broad-spectrum antibiotics may have some relevance to drug resistant occurrence. The application of carbapenems or sulbactam, or their sequential use, in combination with other agents may produce good effects.

Acinetobacter Infections ; drug therapy ; microbiology ; Acinetobacter baumannii ; drug effects ; Anti-Infective Agents ; therapeutic use ; Cross Infection ; drug therapy ; microbiology ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; Middle Aged

IN the presence of septic shock, every hour in delaying the administration of effective antibiotics is associated with a measurable increase in mortality. This is especially true for neutropenic patients with septic shock.1 As there is a higher incidence of involving multi-drug resistant pathogens for neutropenic patients, the decision on antibiotics regime remains a challenge for physicians.2 Immunosuppression and previous antibacterial use are factors that promote the spread of multi-drug resistant pathogens, and the possibility of co-existing multi-drug resistant pathogens should be suspected when treating patients with these risk factors who developed refractory shock. Here we present a case with neutropenic fever and refractory shock whose blood culture yielded multi-drug resistant Acinetobacter baumannii and carbapenem- resistant Klebsiella pneumoniae.
Acinetobacter Infections ; blood ; drug therapy ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Adult ; Bacteremia ; blood ; drug therapy ; microbiology ; Carbapenems ; administration & dosage ; pharmacology ; therapeutic use ; Drug Resistance, Multiple, Bacterial ; Fatal Outcome ; Humans ; Klebsiella Infections ; blood ; drug therapy ; microbiology ; Klebsiella pneumoniae ; drug effects ; isolation & purification ; Male ; Shock, Septic ; blood ; drug therapy ; microbiology

OBJECTIVETo analyze the detection, drug resistance, and status of infection of Acinetobacter baumannii (AB) in burn ICU during 3 years.

METHODSA total of 2 010 specimens of wound secretion, blood, venous catheter attachment, sputum, stool and urine were collected from 505 burn patients hospitalized in our burn ICU from January 2011 to December 2013, and bacterial culture was performed. Pathogens were identified by automatic microorganism identifying and drug sensitivity analyzer. Drug resistance of all the obtained AB to 16 antibiotics commonly used in clinic, including cefoperazone/sulbactam, polymyxin, etc., was tested with K-B paper disk diffusion method. Patients with AB infection were ascertained. The WHONET 5.6 software was used to analyze the distribution of pathogens during 3 years, the isolation of AB with different sources and the status of drug resistance of AB to 16 antibiotics each year, and the status of patients with AB infection, and their outcome.

RESULTSA total of 961 strains of pathogens were isolated, among which 185 (19.25%) strains were Gram positive cocci, 728 (75.75%) strains were Gram negative bacilli, and 48 (4.99%) strains were fungi. A total of 172 strains of AB were isolated, ranking the second place among all the detected pathogens, with 67 (38.95%) strains from wound secretion, 11 (6.40%) strains from blood, 23 (13.37%) strains from venous catheter attachment, and 71 (41.28%) strains from sputum, no AB strain was isolated from feces or urine. The AB strains were found sensitive to polymyxin and with relatively low drug resistance rate to minocycline, while the drug resistance rates were over 80.0% to the other 14 antibiotics commonly used in clinic in 2013. AB culture of wound secretion was positive in 27 patients. Among them, 7 patients suffered from wound infection, and the wound infection was caused by AB in 1 out of the 7 patients. AB culture of blood was positive in 7 patients. Among them, 3 patients suffered from bloodstream infection, and the infection was due to AB invasion in 1 out of the 3 patients. AB culture of venous catheter attachment was positive in 20 patients. Among them, 8 patients suffered from bloodstream infection, and the infection was due to AB invasion in 1 out of the 8 patients. AB culture of sputum was positive in 35 patients. Among them, 13 patients suffered from ventilatory associated pneumonia, and 2 out of the 13 patients were diagnosed as AB infection. A total of 69 patients were AB culture positive, among them 64 patients were cured, 2 patients were transferred to other hospitals, and 3 patients died, with the mortality rate of 4.35%.

CONCLUSIONSAB in our burn ICU has a high detection rate and extensive drug resistance in above-mentioned 3 years. However, AB was mainly colonized in patients with extensive burns with a low mortality rate.

Acinetobacter Infections ; drug therapy ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Anti-Bacterial Agents ; pharmacology ; Burns ; microbiology ; Cross Infection ; Drug Resistance ; Gram-Negative Bacteria ; isolation & purification ; Humans ; Intensive Care Units ; Microbial Sensitivity Tests

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.
Vancomycin Resistance ; Vancomycin/pharmacology ; Population Surveillance ; Microbial Sensitivity Tests ; Korea/epidemiology ; Klebsiella pneumoniae/drug effects/isolation & purification ; Klebsiella Infections/drug therapy/epidemiology/microbiology ; Imipenem/pharmacology ; Humans ; Gram-Positive Bacterial Infections/drug therapy/epidemiology/*microbiology ; Gram-Negative Bacterial Infections/drug therapy/epidemiology/*microbiology ; Gammaproteobacteria/*drug effects/isolation & purification ; Fluoroquinolones/pharmacology ; Enterococcus faecium/*drug effects/isolation & purification ; *Drug Resistance, Bacterial ; Anti-Bacterial Agents/*pharmacology ; Amikacin/pharmacology ; Acinetobacter Infections/drug therapy/epidemiology/microbiology ; Acinetobacter/drug effects/isolation & purification

PURPOSE: The increasing prevalence of antimicrobial resistant bacteria has become a serious worldwide problem. The aim of this study was to analyze antimicrobial resistance data generated in 2009 by hospitals and commercial laboratories participating in the Korean Nationwide Surveillance of Antimicrobial Resistance program. MATERIALS AND METHODS: Susceptibility data were collected from 24 hospitals and two commercial laboratories. In the analysis, resistance did not include intermediate susceptibility. Duplicate isolates were excluded from the analysis of hospital isolates, but not from the commercial laboratory isolates. RESULTS: Among the hospital isolates, methicillin-resistant Staphylococcus aureus, penicillin G-non-susceptible Streptococcus pneumoniae based on meningitis breakpoint, and ampicillin-resistant Enterococcus faecium remained highly prevalent. The proportion of vancomycin-resistant E. faecium gradually increased to 29%. Ceftazidime-resistant Escherichia coli and Klebsiella pneumoniae increased to 17% and 33%, respectively, and fluoroquinolone-resistant K. pneumoniae, Acinetobacter spp. and Pseudomonas aeruginosa increased to 33%, 67% and 39%, respectively. Amikacin-resistant Acinetobacter spp. increased to 48%. Imipenem-resistant Acinetobacter spp. and P. aeruginosa increased to 51% and 26%, respectively. Higher resistance rates were observed in intensive care unit (ICU) isolates than in non-ICU isolates among the isolates from hospitals. Resistance rates were higher in hospital isolates than in clinic isolates among the isolates from commercial laboratories. CONCLUSION: Among the hospital isolates, ceftazidime-resistant K. pneumoniae and fluoroquinolone-resistant K. pneumoniae, Acinetobacter spp., and P. aeruginosa further increased. The increase in imipenem resistance was slight in P. aeruginosa, but drastic in Acinetobacter spp. The problematic antimicrobial-organism combinations were much more prevalent among ICU isolates.
Acinetobacter/*drug effects/isolation & purification ; Acinetobacter Infections/drug therapy/microbiology ; Amikacin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Carbapenems/pharmacology ; Cross Infection/drug therapy/microbiology ; *Drug Resistance, Bacterial ; Fluoroquinolones/pharmacology ; Humans ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification ; Republic of Korea

OBJECTIVEThis study aimed to summarize the clinical characteristics and antimicrobial resistance of carbapenem-resistant Acinetobacter baumannii (CRAB) infections in children, identify its risk factors and to raise the level of diagnosis and treatment of this disease.

METHODThe data of clinical and antimicrobial susceptibility of 32 cases of CRAB and 64 cases of carbapenem-susceptible Acinetobacter baumannii (CSAB) infections as control seen between January 1, 2004 and December 31, 2010 in Yuying Children's Hospital Affiliated to Wenzhou Medical College were analyzed retrospectively.

RESULTThirty-two cases of CRAB infections were identified, 21 were male and 11 female. The ages ranged from 1 day to 16 years (median age 43 days) ,among whom 14 (44%) were aged < or = 28 days; 28 cases (88%) were diagnosed as hospital-acquired pneumonia (HAP) and 4 cases (12%) had wound infection. The common primary diseases of the cases were neonatal respiratory distress syndrome (n = 12, 38%), followed by congenital heart disease (n = 5,16%) and open fractures (n = 5,16%). Before the isolation of CRAB, 10 cases (31%) had received major surgery;29 patients (91%) had stayed in ICUs, 26 cases (81%) had received tracheal intubation and mechanical ventilation,the ventilation time was 2 -249 days (median: 12 days). Carbapenem was used in 17 cases (53%) previously, 13 (41%) had received beta-lactam/beta-lactamase inhibitor combinations, 8 (25%) had used 3rd-generation cephalosporins within 2 weeks before the isolation of CRAB. Sixteen cases (50%) were cured, 12 cases (38%) were improved, parents of 1 case(3%) automatically gave up hospitalization without being cured and 3 cases (9%) died. Forty-nine CRAB strains were isolated from the 32 cases, accounting for 10. 4% of AB isolation strains in the same period, in which 40 strains (82%) were isolated from sputum specimens and 9 strains (18%) from open wounds secretions. All 49 strains showed multidrug-resistance (MDR), of which 13 strains (27%) were pandrug-resistant (PDR) to the common antimicrobials. The rates of resistance to ampicillin-sulbactam and cephalosporins were 90% and more than 85%, respectively; while the rates of resistance to cefoperazone-sulbactam were 19%, the lowest among the tested agents. In multivariate analysis, receiving surgery (OR = 8.450), tracheal intubation and mechanical ventilation for more than 10 days (OR = 6.366) and previous use of carbapenems (OR = 7.084) were independent risk factors for CRAB infections.

CONCLUSIONNosocomial infections in children due to CRAB infections mainly cause HAP and open wound infection. Previous surgery, prolonged tracheal intubation and mechanical ventilation for more than 10 days and previous carbapenems therapy within 2 weeks before the isolation of CRAB were independent risk factors for CRAB infections. CRAB showed MDR or even PDR to the common antimicrobials, which made great difficulties in antibiotic choices.

Acinetobacter Infections ; drug therapy ; microbiology ; Acinetobacter baumannii ; drug effects ; Adolescent ; Anti-Infective Agents ; pharmacology ; Carbapenems ; pharmacology ; Child ; Child, Preschool ; Cross Infection ; drug therapy ; microbiology ; Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Pneumonia, Bacterial ; drug therapy ; microbiology ; Retrospective Studies

The emergence of multidrug-resistant gram-negative bacteria is challenging the treatment of serious nosocomial infections. This is an international trend that is mirrored in Singapore too. Reports of strains resistant to all currently available agents have surfaced here and possibly have taken root here as well. The direst situation is among the non-fermenters, Pseudomonas aeruginosa and Acinetobacter baumannii. This is followed closely by the Enterobacteriaceae family with their array of extended-spectrum beta-lactamases, AmpC beta-lactamases and carbapenemases. There are also resistance mechanisms such as efflux pumps and porins downregulation that effect resistance against multiple classes of agents. Potentiating these developments is the dwindling "pipeline" of new agents. Hence, there is a real concern that we are running out of options for our patients. Novel antibiotic combinations, enhanced infection control, antibiotic cycling, computer-assisted programmes, and maybe in the distant future, non-antimicrobial agents is all that we have.
Acinetobacter Infections ; drug therapy ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Drug Resistance, Multiple, Bacterial ; drug effects ; Forecasting ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections ; drug therapy ; microbiology ; Pseudomonas aeruginosa ; drug effects ; isolation & purification ; Singapore ; beta-Lactamases ; metabolism

BACKGROUND/AIMS: Frequent pathogens of nosocomial meningitis were investigated and the adequacy of empiric antibiotic therapy was assessed. Outcomes of nosocomial meningitis were also evaluated. METHODS: Ninety-one patients, who were diagnosed and treated for nosocomial meningitis at a single tertiary hospital in Daegu, Korea for 10 years, were included. Medical record and electronic laboratory data on the causative pathogens, antibiotics used, and outcomes were retrospectively investigated. RESULTS: Coagulase-negative Staphylococcus (40.9%) was the most common pathogen, followed by Acinetobacter (32.5%). Both were cultured as a single organism in cerebrospinal fluid (CSF). Seventy-eight patients (85.7%) had infections related to external ventricular drains (EVD). The most common empirical antibiotics were extended-spectrum beta-lactam antibiotics plus vancomycin (35/91, 38.6%). Of the 27 patients who had cultured Acinetobacter in CSF, 10 (37%) were given the wrong empirical antibiotic treatment. Seven of the 27 patients (26.9%) with cultured Acinetobacter died, and overall mortality of the 91 patients was 16.5%. In the multivariate analysis, the presence of combined septic shock (p < 0.001) and a persistent EVD state (p = 0.021) were associated with a poor prognosis. CONCLUSIONS: Acinetobacter is one of the leading pathogens of nosocomial meningitis and may lead to inadequate coverage of empiric antibiotic therapy due to increasing resistance. An EVD should be removed early in cases of suspected nosocomial meningitis, and carbapenem might be required for the poor treatment response.
Acinetobacter/classification/*isolation & purification ; Acinetobacter Infections/cerebrospinal fluid/diagnosis/*drug therapy/*microbiology ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Cerebrospinal Fluid/microbiology ; Cross Infection/cerebrospinal fluid/diagnosis/*microbiology/mortality/*therapy ; Drug Resistance, Bacterial ; Female ; Humans ; Logistic Models ; Male ; Meningitis, Bacterial/cerebrospinal fluid/diagnosis/*drug therapy/*microbiology/mortality ; Middle Aged ; Multivariate Analysis ; Odds Ratio ; Republic of Korea ; Retrospective Studies ; Risk Assessment ; Risk Factors ; Staphylococcal Infections/cerebrospinal fluid/diagnosis/*drug therapy/*microbiology/mortality ; Staphylococcus/classification/*isolation & purification ; Time Factors ; Treatment Outcome ; Young Adult