| Background:Pseudomonas aeruginosa is non-fermentative gram-negative bacilli, widely exist in nature. Pseudomonas aeruginosa belongs to the human pathogens, change or damage the body's normal defense mechanisms, resulting in lower immune function are easy to infect it, serious infection can lead to septicemia. According to the data of the Chinese ministry of bacterial resistance monitoring network(Mohnarin 2006-2007), Pseudomonas aeruginosa of 4.7% was the third proportion in gram-negative bacilli, following Escherichia coli(18.7%) and Klebsiella(7.3%). Pseudomonas aeruginosa of 111 isolates was the second, following Escherichia coli(190 isolates) in the septicemia pathogen in southern hospital since 2003-2008.Pseudomonas aeruginosa occurs resistance with complex mechanism, due to its structure and the result antimicrobial induced. The resistance status of Pseudomonas aeruginosa becomes more and more serious, along with the wide application of antimicrobial agents. Pseudomonas aeruginosa septicemia is severe systemic infection with rapid progression and high mortality. The mortality of Pseudomonas aeruginosa septicemia reported by foreign literature is between 21% and 39%, and is more than that of Staphylococcus aureus septicemia. At present domestic clinical research about Pseudomonas aeruginosa septicemia is few. Objective:1. To explore the drug resistance status of Pseudomonas aeruginosa.2. To investigate the risk factors related with mortality for Pseudomonas aeruginosa septicemia.Methods:1. The date of 89 cases of Pseudomonas aeruginosa septicemia from Jan 2004 to May 2009 in Nanfang Hospital were collected.2. The date of the included cases were studied retrospectively. The clinical characteristics of initial septicemia, including:time of intial blood culture, age, gender, hospital department, hospital infection type, duration of hospital stay before septicemia, length of hospitalization, stay-in-ICU, comorbid illness, invasive procedure, immunosuppressive therapy, laboratory findings, source of septicemia, results of initial blood culture, antibiotic treatments during the 15 days prior to septicemia, and outcome were recorded.3. Pseudomonas aeruginosa from blood cultures in patients was isolated by PHOEN IX 100 automation system. Antibiotic susceptibility test was performed by K-B disk diffusion method. Pseudomonas aeruginosa was confirmed by using standard of National Commitee for Clinical Laboratory Standards into sensitive, resistant, and intermediate.4. Prognostic index:the 30-day mortality and survival time.5. All the data were analyzed by SPSS software 13.0 version. The drug resistance status of Pseudomonas aeruginosa was analyzed withχ2 test(Pearson Chi-Square or Fisher's Exact Test). The prognostic factors of univariate analysis:The measurement data was analyzed with t test(equal variances assumed), or Satterthwaite estimation t test(equal variances not assumed). The enumeration data was analyzed withχ2 test(Pearson Chi-Square or Fisher's Exact Test). On the basis of univariate analysis, the variables P<0.05 were analyzed with binary Logistic regression analysis, identifing the independent risk factors of mortality for Pseudomonas aeruginosa septicemia. The survival time was analyzed with Kaplan-Meier method. P<0.05 is a statistically significant difference.Results:1.89 patients with Pseudomonas aeruginosa septicemia were included in this retrospective study.14 patients belong to community infection, and 75 patients belong to hospital infection.52 patients were male, and 37 patients were female.42 patients were in hematology specialty,10 patients were in pediatric ward,8 patients were in nephrology department,6 patients were in division of respiratory disease.23 patients were in other wards.2. The resistant rates of Pseudomonas aeruginosa strains to 10 common usable antibiotics were less than 30%. Meropenem has the lowest resistant rate 6.82%, followed by cefoperazone/sulbactam 8.64%. The resistant rates to amikacin, cefepime, piperacillin/tazobactam, ceftazidime, imipenem, ciprofloxacin, levoflozacin were 10.11%,11.11%,12.79%,13.95%,15.91%,17.07%,20.00% respectively. Aztreonam has the highest resistant rate 26.79%. The multidrug resistance rate of Pseudomonas aeruginosa strains was 16.85%, and pan-drug resistance rate of Pseudomonas aeruginosa strains was 3.37%.3. The resistant rates of imipenem-resistant Pseudomonas aeruginosa strains to ceftazidime (P=0.000), cefepime (P=0.000), cefoperazone/sulbactam (P=0.001), piperacillin/tazobactam (P=0.000), ciprofloxacin (P=0.000), levoflozacin (P=0.000), amikacin (P=0.001), meropenem (P=0.000) were more than that of the imipenem-susceptible strains, while remarkable differences (P<0.05). 4. The resistant rates of meropenem-resistant Pseudomonas aeruginosa strains to ceftazidime (P=0.003), cefepime (P=0.000), cefoperazone/sulbactam (P=0.000), piperacillin/tazobactam (P=0.000), ciprofloxacin (P=0.000), levoflozacin (P=0.000), amikacin(P=0.001), imipenem (P=0.000) were more than that of meropenem-susceptible strains, while remarkable differences (P<0.05).5. The resistant rates of meropenem-resistant Pseudomonas aeruginosa strains (P=0.000) or imipenem-resistant Pseudomonas aeruginosa strains (P=0.000) to multidrug resistance were more than that of the sensitive strains, while remarkable differences (P<0.05).6. The resistant rates of Pseudomonas aeruginosa strains isolated from community infection patients between hospital infection patients to 10 common usable antibiotics were not statistically significant differences, P>0.05. Same were for different gender patients.7. The resistant rates of Pseudomonas aeruginosa strains isolated from hematology specialty ward to ceftazidime (χ2=4.993, P=0.025), cefepime (P=0.032), cefoperazone/sulbactam (P=0.012), aztreonam(χ2=8.984, P=0.003), ciprofloxacin (χ2=7.495, P=0.006) were less than that of strains isolated from other wards, while remarkable differences (P<0.05). But no differences were to piperacillin/tazobactam(χ2=1.877, P=0.171), levoflozacin(χ2=3.013, P=0.083), amikacin(P=0.163), imipenem (χ2=0.158, P=0.691), meropenem(P=0.205), P>0.05.8. The resistant rates of Pseudomonas aeruginosa strains isolated from the patients using carbapenem antibiotics to ceftazidime (P=0.000), cefepime (P=0.003), cefoperazone/sulbactam (P=0.032), piperacillin/tazobactam (P=0.012), aztreonam (P=0.008), ciprofloxacin (P=0.015), levoflozacin (P=0.005), imipenem (P=0.000), meropenem (P=0.018) were more than that of strains isolated from the patients not using carbapenem, while remarkable differences (P<0.05). 9. The resistant rates of Pseudomonas aeruginosa strains isolated from the patients using two or more antibiotics were more than that of strains isolated from the patients using one antibiotics or not.10.65 patients survived within 30 days, and 24 patienst died.30-day mortality was 27%.11. The univariate analysis results:the factors associated with the higher 30-day mortality were Pitt Bacteremia Score(χ2=-9.050,P=0.000), plasma albumin(χ2=3.030,P=0.003), indwelling central venous catheter(χ2=4.113,P=0.043), imipenem-resistant Pseudomonas aeruginosa(P=0.000), meropenem-resistant Pseudomonas aeruginosa(P=0.005), multidrug resistance Pseudomonas aeruginosa(P=0.000), inappropriate empiric antibiotic therapy(χ2=28.578,P=0.000), empiric antibiotic therapy(χ2=6.493,P=0.019), the differences were statistically significant, P<0.05. Empiric monotherapy with inappropriate antibiotic therapy of 36.2%, empiric combination antibiotic therapy with inappropriate antibiotic therapy of 14.3%, the difference of proportion was statistically significant,χ2=5.543,P=0.019.12. Binary Logistic regression analysis identified two independent risk factors of mortality:Pitt Bacteremia Score(P=0.000, OR=4.313) and inappropriate empiric antibiotic therapy(P=0.001, OR=29.471).13. Compared to monotherapy, there was a trend to increase survival time for neutropenic patients receiving empiric combination antibiotic therapy, but the difference was not statistically significant(χ2=0.847,P=0.358). Compared to monotherapy, for neutropenic patients receiving definite combination antibiotic therapy, the difference between survival time was not statistically significant(χ2=0.036,P=0.849).14. Compared to monotherapy, for non-neutropenic patients receiving empiric combination antibiotic therapy, the survival time were longer and survival rate was higher, the difference was statistically significant(χ2=4.186,P=0.041). Compared to monotherapy, for non-neutropenic patients receiving definite combination antibiotic therapy, the difference between survival time was not statistically significant(χ2=0.348,P=0.555).Conclusions:1. The resistant rates of Pseudomonas aeruginosa strains to 10 common usable antibiotics were less than 30%. Meropenem has the lowest resistant rate, followed by cefoperazone/sulbactam. Aztreonam has the highest resistant rate.2. The resistant rates of imipenem-resistant Pseudomonas aeruginosa strains or meropenem-resistant Pseudomonas aeruginosa strains to common usable antibiotics were more than that of the sensitive strains. Same were multidrug resistance strains.3. Using carbapenem antibiotics and using two or more antibiotics and aggravate resistance rates of Pseudomonas aeruginosa strains.4. High Pitt Bacteremia Score and inappropriate empiric antibiotic therapy were independent mortality risk factors for Pseudomonas aeruginosa septicemia.5. Empiric combination antibiotic therapy can reduce the frequency of inappropriate antibiotic therapy.6. Compared to monotherapy, for non-neutropenic patients receiving empiric combination antibiotic therapy, the mortality was lower, and the survival time was longer. |
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