OBJECTIVETo investigate the resistance genes and antibiotic resistance patterns against beta-lactams in Pseudomonas aeruginosa prevalent in burn ward.

METHODSK-B method was performed to test bacterial resistance patterns against 9 species of beta-lactams in Pseudomonas aeruginosa isolated from wounds and dressings of the patient in burn wards. Seven species of resistance genes against beta-lactams were detected with PCR. Tazobactam-inhibited piperacillin resistance test was performed to study whether the above strains produce extended spectrum beta-lactams.

RESULTSAll 12 strains of bacteria with resistance genes detected were resistant to penicillin and cephalosporins (100%), among them 11 were resistant to all antibiotics. Tazobactam-inhibited piperacillin resistance test demonstrated that all strains with resistance genes were ESBLs.

CONCLUSIONHigh incidence of beta-lactams resistance genes is found in Pseudomonas aeruginosa isolated from burn ward, and they have close relationship with the occurrence of multiple drug-resistance.

Burn Units ; Burns ; microbiology ; Genes, Bacterial ; Humans ; Pseudomonas aeruginosa ; drug effects ; genetics ; isolation & purification ; beta-Lactam Resistance ; genetics

OBJECTIVETo analyze the isolation and the in vitro susceptibility of P. aeruginosa to antibiotics in our burn ward.

METHODSFive hundred and thirty six burn patients admitted to our ward from 1997 to 2003 were enrolled in the study, and the wound excretion, the tips of the venous catheter, the subeschar tissue samples, and the blood samples were collected for bacterial identification and antibiotic susceptibility test with VITEK-AMS system.

RESULTSThe isolation rate of P. aeruginosa from 1997 to 2003 was 24.51%, 23.94%, 21.01%, 40.06%, 36.17%, 46.76% and 55.72%, respectively. The antibiotic effect of the third generation of Cephalosporins against the said bacteria showed a tendency to decline. The susceptibility rate to Cefoperazone, Ceftazidime and Cefotaxime were respectively 71%, 66% and 79% in 1997; 47%, 25%, 39% in 1998; 22%, 16%, 25% in 2002; The third generation cephalosporins had almost lost their antibiotic activity against P. aeruginosa in 2003, with the susceptibility rate to Cefotaxime lowered to 2%. The susceptibility rate to Imipenem from 1997 to 2003 was 76%, 33%, 45%, 11%, 41%, 31%and 4%, respectively.

CONCLUSIONThe isolation rates of P. aeruginosa were steady during the period from 1997 to 1999, and they began to increase in 2000. The bacterial resistance to antibiotics increased gradually in recent years, and the strains of P. aeruginosa had become multi-drug resistant.

Anti-Bacterial Agents ; pharmacology ; Burn Units ; Burns ; microbiology ; Drug Resistance, Multiple, Bacterial ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Pseudomonas Infections ; microbiology ; Pseudomonas aeruginosa ; drug effects ; isolation & purification

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.
Pseudomonas aeruginosa/drug effects/isolation & purification ; Microbial Sensitivity Tests ; Laboratories ; Korea ; Klebsiella pneumoniae/drug effects/isolation & purification ; Imipenem/*pharmacology ; Hospitals ; Gammaproteobacteria/*drug effects/isolation & purification ; Drug Resistance, Multiple, Bacterial ; Ceftazidime/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Acinetobacter/drug effects/isolation & purification

OBJECTIVETo investigate the distribution of burn pathogens and their antibiotic resistance in a burn unit, so as to provide reference for clinical practice.

METHODSThree hundred and forty-eight burn patients hospitalized in our department were enrolled in this study. The pathogens isolated from the wounds, blood, venous catheter, sputum, urine, purulent discharge of wounds in these patients, and their antibiotic resistance were surveyed by retrospective analysis from Jan, 2001 to Dec, 2006.

RESULTSTotal-ly 464 strains were isolated, among which Gram negative (G-) bacilli accounted for 52.6%, Gram positive microorganisms (G+) accounted for 40.5%, and fungi accounted for 6.9%. The main pathogens were Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter species and Escherichia coli, among which Staphylococcus aureus (MRSA) was predominant (93.5%). MRSA was 100% resistant to levofloxacin, penicillium, oxacillin, and it was also resistant to other antibiotics except Vancomycin. The resistance rate of Pseudomonas aeruginosa to Cefoperazone/Sulbactam, Imipenem and cefepime were 15.8%, 36.8%, 33.3%, respectively.

CONCLUSIONStaphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter species and Escherichia coli were predominant in the burn unit,among them Staphylococcus aureus and Acinetobacter were more resistant to antibiotics.

Acinetobacter baumannii ; drug effects ; isolation & purification ; Burn Units ; Burns ; microbiology ; Cross Infection ; microbiology ; Drug Resistance, Bacterial ; Escherichia coli ; drug effects ; isolation & purification ; Humans ; Pseudomonas aeruginosa ; drug effects ; isolation & purification ; Retrospective Studies ; Staphylococcus aureus ; drug effects ; isolation & purification

OBJECTIVETo study changes in the drug-resistance of Pseudomonas aeruginosa (PA) and the use of antibiotics in burn wards so as to optimize the use of antibiotic in the future.

METHODSBacteria were isolated from specimens of blood, venous catheter, stool, sputum, urine, wound tissue from 5717 patients hospitalized in our burn wards within the duration of January 2005 to December 2009. The number of specimens examined and positive rates of bacteria were calculated. Changes in constituent ratio of cocci and bacilli, spectrum of bacteria, the drug-resistance rate of PA, and the usage of antibiotics were analyzed. The number of specimens examined, constituent ratio of cocci and bacilli, drug-resistance rate were processed with chi-square test. Bivariate correlation analysis was performed between the usage of antibiotics and the drug-resistance rate.

RESULTS(1) The number of specimens examined showed no statistical difference during the five years (with rates from 73.2% to 76.1%, χ(2) = 5.583, P > 0.05), while constituent ratio of cocci and bacilli showed statistical difference (with ratios from 105:134 to 169:126, χ(2) = 14.806, P < 0.01). The positive rates of bacteria were increasing in the five years. (2) One thousand six hundred and seventy-five strains were identified during the five years from different kinds of specimens, with 29 from blood, 39 from venous catheter, 3 from stool, 157 from sputum, 13 from urine, and 1434 from wound tissue. Among them, Staphylococcus aureus accounted for 28% to 42%, PA accounted for 10% to 25%, Acinetobacter baumannii accounted for 10% to 19%, and they were the predominant strains. (3) The difference among drug-resistance rates of PA to each kind of 12 antibiotics during the five years were statistically significant (with χ(2) values from 47.911 to 308.095, P values all below 0.01). The drug-resistance rates of PA to some antibiotics showed downward trend in the former four years, including amikacin, ceftazidime, and imipenem/cilastatin, but it rebounded in the fifth year. (4) There was descending trend in usage of cefoperazone/sulbactam and levofloxacin, but vancomycin was always used widely. (5) Drug-resistance rates of PA to 7 antibiotics, including amikacin, imipenem/cilastatin, and ciprofloxacin, etc., were positively correlated with usage of various antibiotics (with r values from 0.879 to 0.978, P < 0.05 or P < 0.01).

CONCLUSIONSIn our burn wards, drug-resistant PA was prevalent. Disinfection and isolation measures, appropriate use of antibiotics, etc. can reduce PA infection.

Anti-Bacterial Agents ; therapeutic use ; Burn Units ; Burns ; drug therapy ; microbiology ; Drug Resistance, Bacterial ; drug effects ; Female ; Humans ; Male ; Pseudomonas Infections ; drug therapy ; microbiology ; Pseudomonas aeruginosa ; drug effects ; isolation & purification

OBJECTIVETo analyze the distribution and drug resistance of bacteria in different wound infections and provide evidence for wound infection control in subtropical regions.

METHODSThis study involved 265 patients from 4 different departments of our hospital who experienced wound infections between July, 2007 and July, 2008. The bacterial strain distribution in the wounds and drug resistance of the bacteria were analyzed.

RESULTSAcinetobacter baumanii (39% of the total strain identified) was the most frequent bacterial strain causing infection of the burn wounds, followed by Proteus mirabilis (20%) and Pseudomonas aeruginosa (20%). E. coli infection was prevalent in the departments of general surgery (37%) and urinary surgery (64%), and Pseudomonas aeruginosa and Pseudomonas pneumonia infections were detected at the rate of 30% and 43% in the urinary surgery department, respectively. Different bacterial strains were found at similar rates around 10% in the wounds of patients undergoing traumatic surgery.

CONCLUSIONDespite that the commonly seen pathogenic bacteria in burn patients including Staphylococcus aureus have been effectively controlled by early application of antibiotics, the opportunistic pathogens such as Acinetobacter baumanii and Proteus mirabilis often survive these antibiotics, and some strains evolve to be drug-resistant and even multi-drug-resistant. E. coli infection is prevalent in general surgery and urinary surgery departments, where Staphylococcus aureus and Pseudomonas aeruginosa infections can also be found frequently. All kinds of bacteria infection are present in trauma surgery department, each found at the rate around 10%.

Acinetobacter baumannii ; drug effects ; isolation & purification ; Adolescent ; Adult ; Burns ; complications ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Escherichia coli ; drug effects ; isolation & purification ; Female ; Humans ; Male ; Middle Aged ; Pseudomonas aeruginosa ; drug effects ; isolation & purification ; Wound Infection ; etiology ; microbiology ; Young Adult

The discovery of quorum sensing (QS) system and its critical role in bacterial virulence have revealed a new way to attack pathogenic bacterium. The pathogenecity of QS deletion mutants decreases significantly. Targeting bacterial QS system is a promising therapeutic approach to control infections and anti-microbial resistance. To obtain natural QS inhibitors from marine organisms, marine fungi (69 strains) were isolated from marine mollusca, and their extracts were screened using improved QSIS2 (Quorum Sensing Inhibitor Selector 2) assay and Chromobacterium violaceum CV026. To improve the efficiency of QSIS2 screening, 2,3,5-triphenyltetrazolium chloride (TTC) staining method was used. Extract from strain QY013 was found to have QS inhibitory activity. Further experiment indicated that pyocyanin in Pseudomonas aeruginosa PAOI and violacein in C. violaceum CV026 were reduced by QY013 extract, without affecting bacterial growth. Morphological and 18S rDNA sequence analysis revealed that strain QY013 was most closely related to Penicillium species. The above results suggest that active constituents from QY013 may be used as novel antimicrobial agents against bacterial infection.
Animals ; Anti-Infective Agents ; isolation & purification ; metabolism ; pharmacology ; Bacterial Physiological Phenomena ; Fungi ; isolation & purification ; physiology ; Marine Biology ; Mollusca ; microbiology ; Penicillium ; isolation & purification ; metabolism ; Pseudomonas aeruginosa ; drug effects ; metabolism ; pathogenicity ; Quorum Sensing ; drug effects ; Virulence ; drug effects

OBJECTIVETo investigate the relationship between the drug resistance of Pseudomonas aeruginosa (PA) isolated from burn patients wounds and its mobile genetic elements, including plasmid, transposon, and integron.

METHODSThirty-two strains of PA were isolated from wounds exudate of hospitalized burn patients in Ningbo No. 2 Hospital. PA drug sensitivity was determined using GNS-448 drug sensitivity card and K-B tests. The genetic markers of plasmid, transposon and integron including traA, traF, tnpA, tnpU, merA, int I 1 were amplified by PCR and verified by gene sequencing.

RESULTSDrug resistant rate of 32 PA strains to gentamicin, amikacin, cefoperazone/sulbactam, ciprofloxacin was 43.7%, 32.0%, 46.8%, 49.9%, respectively. PA drug resistant rates to piperacillin, cefotaxime, ceftazidime, cefepime, aztreonam, piperacillin/tazobactam, levofloxacin, imipenem and meropenem were all above 56.0%. Seventeen out of 32 PA strains were found to carry transposon and (or) integron genetic markers. One strain was positive for both tnpA and merA, 8 strains were positive for both merA and int I 1, 1 strain was only positive for tnpA, 2 strains were only positive for merA, and 5 strains were positive for int I 1 only.

CONCLUSIONSPA isolated from burn wounds of hospitalized patients in Ningbo No. 2 Hospital is seriously drug resistant, which may relate with its high positive rate of mobile genetic elements of transposon and (or) integron.

Anti-Bacterial Agents ; pharmacology ; Burns ; microbiology ; DNA Transposable Elements ; Drug Resistance, Multiple, Bacterial ; genetics ; Humans ; Integrons ; Microbial Sensitivity Tests ; Plasmids ; Pseudomonas aeruginosa ; drug effects ; genetics ; isolation & purification

OBJECTIVETo investigate drug-resistant genes associated with beta-lactams and aminoglycosides in clinically isolated Pseudomonas aeruginosa.

METHODSTwenty strains of Pseudomonas aeruginosa were isolated from wound excretion of hospitalized burn patients. The strains resistant to 14 antibiotics were selected for detection of 16 kind of drug-resistant genes (TEM, SHV, OXA-10 cluster, PER, VEB, GES, CARB, CTX-M- I, IMP, VIM, SPM, GIM, DHA, MOX, FOX, oprD2) and 6 kind of aminoglycoside modification genes (aac(3)- I, aac(3)-II, aac(6')-I, aac(6')-II, ant (3")- I , ant(2")- I) in them by PCR.

RESULTSAmong the 20 strains resistant to beta-lactam , all of them were TEM and GES positive (100%), oprD2 gene depletion in 5 strains (25%). All other genes were negative. Among aminoglycoside resistant genes, 20 strains were aac (6') - I positive (100%), 7 were ant (2") - I positive (35%), and negative for other stains.

CONCLUSIONThere were very high existence rates of TEM, GES and aac (6')- I genes in Pseudomonas aeruginosa isolated from clinical burn patients. The fact that GES-5 gene has also been detected in Pseudomonas aeruginosa, suggesting this organism is highly drug resistant in our burn unit.

Aminoglycosides ; pharmacology ; Drug Resistance, Multiple, Bacterial ; genetics ; Humans ; Pseudomonas aeruginosa ; drug effects ; genetics ; isolation & purification ; beta-Lactam Resistance ; genetics ; beta-Lactams ; pharmacology

OBJECTIVETo investigate the change in the antibiotic resistant spectrum of Pseudomonas aeruginosa (PA) isolated from burn wounds and the production of inducible beta-lactamase.

METHODSVITEK-AMS system (total automatic bacterial identification and drug sensitivity system) and E-test concentration gradient were employed to perform bacterial identification and antibiotic sensitivity tests. K-B method was applied to detect inducible enzyme.

RESULTSThe resistance of PA to Cephalosporin and Imipenem was increased in the past 4 years from June of 1996 to June of 2000. Whereas the resistance to Cefoperazone/Sulbactam was least. There was an obvious difference of the resistance of PA to antibiotics during the 4 years (P < 0.05). The resistant rate to Imipenem ranged from 20% to 40%. PA was able to produce inducible enzymes among 120 strains of wild type of PA occupying 72.5% with Imipenam as the inducing agent.

CONCLUSIONThe analysis of the antibiotic resistance of PA and the detection of inducible enzymes could be monitored from time to time and helpful in the correction of the use of antibiotics. Constant monitoring of antibiotic resistance might be beneficial to the prevention of outbreak of epidemics of PA infection in a burn unit.

Burns ; microbiology ; Cephalosporins ; pharmacology ; Drug Resistance, Bacterial ; Enzyme Induction ; Humans ; Imipenem ; pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; drug effects ; isolation & purification