ABSTRACT
Background: Pseudomonas aeruginosa is an opportunistic pathogen causing nosocomial infections in many hospitals. The aim of this study was to compare the different epidemiological typing techniques and their effectiveness in typing and discrimination of nosocomial Pseudomonas aeroginosa isolates
Methods: Seventy eight confirmed nosocomial Pseudomonus aeroginosa out of 1520 different sample [nosocomial infections and environmental samples] were collected during a period of one year. Six typing methods were evaluated, utilizing the confirmed 78 Pseudomonas strains, to assess their usefulness as tools to study the bacterial diversity. The methods used were antibiogram, pyocin typing, serotyping, extracellular enzyme typing, automated ribotyping and pulsed field gel electrophoresis [PFGE
Results: The distinctive capacity of four phenotyping methods was determined and compared to PFGE. Resistance to the antibiotics tested was in the 37.2% to 98.7% range; Imipenem was the most effective, whereas augmentin, carbenicillin and ceftazidime were the least effective antibiotics. Antibiogram for 78 isolates discriminate 13 different patterns
Pulsed field gel electrophoresis yielded 56 distinct types of P.aeruginosa with 100% distinction capacity [78/78] as all the strains were typable. Compared to PFGE, the distinctive capacities were 88.5% [69/78] for serotyping, 91% [71/78] for Pyocin typing and 100% [78/78] for automated ribotyping analysis. The results obtained in PFGE, were the easiest to read and interpret and most discriminating [0.99], followed by the pyocin typing [0.96], whereas ribotyping had [0.90] discriminatory power
Conclusion: Our results indicated that P.aeruginosa infections in Suez Canal University Hospital, mainly affect the hospitalized patients in orthopedic wards, surgical wards and burn units and played a great role in hospital associated infections. Imipenem was the best antibiotic as far as bacterial resistance is considered. Although, the lack of major PFGE type confirmed that no P.aeruginosa outbreak, typing results showed that PFGE was the best used typing method regarding high typability, sensitivity and discriminatory power. The used typing methods showed that cross transmission and treatment failure were the two main problems for spread of nosocomial infections inside surgical wards and should be considered to prevent this bacterial infection in medical units
ABSTRACT
Background: The genus Klebsiellae pneumonia is considered an important pathogen causing ventilator-associated pneumonia [VAP]. Beta lactam antimicrobial agents are the most commonly used treatment of bacterial infections. Extended spectrum p-lactamases [ESBLs] are enzymes that mediate resistance to extended-spectrum cephalosporins and monobactams but not cephamycins or carbapenems. ESBLs are considered an important source of morbidity and mortality in patients receiving mechanical ventilation. These enzymes are numerous and mutate continuously in response to heavy pressure of antibiotics use and misuse. This study aimed to study the role of SHV genes as they are one of the most common and important genes encode these enzymes and prevalence of ESBLs producing Klebsiellae pneumonia causing VAP in ICU patients and antimicrobial susceptibility pattern to prevent spread of this type of isolates
Methods: Endotracheal tube aspirates specimens from patients clinically diagnosed as VAP were collected according to CDC criteria within one year in two hospitals in Saudi Arabia; Buraidah Central Hospital and King Fahd Specialist Hospital Klebsiellae pneumonia was identified using conventional identification method and by automated MicroScan machine
Diagnosis of ESBLs producing isolates were done using both phenotypic double disk Synergy diffusion method [DDST] and also was confirmed by the automated MicroScan machine using panel for Gram negative by minimal inhibitory concentration [MIC] method. Detection of SHV genes were done to ESBLs positive isolates using polymerase chain reaction [PCR] assay
Results: Twenty one isolates of Klebsiellae pneumonia were isolated; 18 of them were ESBLs positive by MIC method [85.7%]. DDST failed to diagnose one isolate only as it gave false negative result compared to MIC confirmatory method. The rate of VAP was 5.6 cases/1000 ventilator-days within one year in the two hospitals. The mean of length of stay in ICU of both hospitals was [mean+/-SD = 9.7+/-7.0]. The mean of ventilator days was 8.4 days [range 2-35 days]
Prevalence of confirmed ESBLs Klebsiellae pneumonia was 26.5% isolated from all VAP cases [18/68] causing VAP in both hospitals. Using PCR method 12 isolates out of 18 were positive for the presence of SHV genes [66.7%]. This enumerated the importance of these genes for production of ESBLs. All ESBLs isolates were resistant to ampicillin, cefazolin, cefuroxime, ceftazidime, cefotaxime, cefepime, piperacillin, [100%] meanwhile these were sensitive to cefoxitin except two isolates only were resistant [11.1%]. All these isolates were sensitive to tigecycline and colistin [100%]. Resistance of ESBLs isolates to amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, moxifloxacin, tetracycline and trimethoprim- sulfamethoxazole were 33.3%, 38%, 33.3%, 22%, 22%, 16.7%, 55.6% and 83.3% respectively. It was found that 55.5% of ESBLs isolates were resistant to amoxicillin/k clavulanate and piperacillin/tazobactam. The least resistance was to imipenem, meropenem, ertapenem and cefoxitin in 2 isolates only [11.1%] for each
Conclusion: Our findings showed the importance of these ESBLs isolates in hospital associated infections especially VAP in ICU and antibiotic resistance especially cephalosporins and penicillin group that could lead to failure of management and restriction for the suitable choice of chemotherapeutic agents by clinicians
Wise use of antimicrobial agents is recommended inside ICU as critically ill patients are more susceptible to infection by these strains. It is recommended to screen for the presence of SHV and other genes by rapid, accurate molecular method in suspected ESBLs isolates to prevent spread of infection among critically ill patients in ICU. Further molecular studies like multiplex PCR, genetic sequencing, restriction fragment length polymorphism [RFLP], isoelectric focusing are needed to study other genes that mediate production of these enzymes
ABSTRACT
Background: Fungal infection particularly due to Candida species is important cause of morbidity and mortality in the ICU. Non-Candida albicans such as C.tropicalis, C.parapsilosis C.glabrata andC.Krusei are emerging as opportunistic pathogens which may add resistance to antifungal agents. The rapid detection and identification of Candida species in clinical laboratories are extremely important for early management of critically ill patients with central line associated blood stream infections [CLABSI]
Patients and methods: Our study has been performed in Buraidah central Hospital and King Fahd Specialized Hospital in the period between July 2009 and June 2012. AH patients who developed clinical signs of CLABSI were eligible. Under complete aseptic technique, blood samples were taken from peripheral vein, central vein and from the central line catheter tip, if removed, for semiquantitative cultures. Another peripheral blood sample was taken within 30 minutes in sterile plain tube without anticoagulant for Polymerase Chain Reaction [PCR] assay
Results: Two hundreds and twelve patients in the two hospitals have developed CLABSI through the period of the study. The overall isolation rate of Candida by using conventional culture and identification method was 9.43% [20/212]. C.albicans was the most frequent species isolated 40% [8/20], followed by non-albicans species as C.tropicalis 2o% [4/20], C.parapsilosis 15% [3/20], C.glabrata 15% [3/20], C.krusei 5% [1/20] and C.dubelinsis 5% [1/20]. The PCR assay yielded positive results in 19 out of the 20 patients proved to be Candida by using the conventional culture method and revealed 20 negative out of 20 samples proved to be negative by the same method. The negative PCR sample out of the 20 positive was due to infection by C.dubelinsis which could not be diagnosed by the used primer. The sensitivity, specificity, positive predictive value [PP V], negative predictive value [NP V] and agreement of PCR compared to culture method as gold standard were 95%, 100%, 100%, 95.2 % and 97.5% respectively
Conclusion: PCR assay is a rapid and highly specific method for early diagnosis of candidaemiae in critically ill patients. This will help the early initiation of antifungal therapy and may save lives especially of immunocompromised patients in ICU
Conclusion: The existence of EBV infection in HCC tissues suggests that EBV may be involved in the hepatocellular carcinogenesis in Egypt. HCV infection may be a major cause of HCC. There is correlation between EBV and HCV in the development of HCC. EBV enhancement the replication of HCV
ABSTRACT
Stenotrophomonus maltophilia is a multidrug resistant nosocomial pathogen for which optimal typing methods are needed to estimate epidemiologic relatedness especially among Intensive Care Unit [ICU]. Ventilator associated pneumonia [VAP] is a common complication in mechanically ventilated patients and it is accompanied by increased mortality. Pulsed field gel electrophoresis [PFGE] was applied to 12 nosocomial strains isolated from patients had VAP and six environmental specimens in ICU in Bahrain Hospital over 15 months period in 2004-2005. Antibiogram as a phenotypic marker failed to discriminate between these isolates. Five antibiogram patterns were identified among 18 isolates with predominance of pattern [I] that resisted five chemotherapeutic agents in 5 isolates [27.8%]. All the strains were sensitive to trimethoprim-sulfamethoxazole but only 72.2%, 55.6%, 44.4%, 22.2% and 11.1% were sensitive to minocycline, levofloxacin, ticarcillin-clavulanic acid, ceftazidime and chloramphenicol respectively. All the strains were typable by the genotypic marker PFGE. It revealed 14 patterns among 18 clinical and innate environmental isolates with a small two clusters included 3 strains that were epidemiologically related. Ten genotypic patterns were detected among twelve clinical isolates meanwhile six patterns were detected among the six environmental isolates. There were similar isolated PFGE patterns between environmental and clinical isolates suggestive of the source of infection to those patients and evidence of patient to patient transmission. These different genotypic patterns indicated different sources and genetic diversity of this opportunistic pathogen. This study proved high typability, sensitivity and discriminatory power of PFGE method for typing of nosocomial Stenotrophomonus maltophilia. It is recommended to add another genotypic marker in further studies like random amplified polymorphic DNA analysis [RAPD] to increase and augment the sensitivity and discriminatory power for typing of this important pathogen and trace the different sources of nosocomial infection
ABSTRACT
Opportunistic fungal infections are increasingly important cause of morbidity and mortality particularly due to Candida species. Non-Candida albicans such as C. tropicalis, C. glabrata and C. Krusei are emerging as opportunistic pathogens ad more resistant to antifungal agents. Urinary tract infections in critically ill patients caused by Candida are increasing in recent years, so identification of Candida to the species level and antifungal susceptibility are very important. Urine samples were collected from critically ill patients in Intensive Care Unit [ICU] from 92 patients. Urine samples were cultured on CLED, blood and Sabouraud dextrose agar [SDA] for diagnosis of Candida. After gram staining subculture was done on: morphologic media included Corn meal and Rice agar Tween 80; chromogenic media included CHROM agar [CMA], BIGGY agar [bismuth ammonium citrate, glucose, glycine and yeast extract]. Results of the previous media were compared with those obtained with API 20 C AUX yeast identification kits. The study revealed an overall isolation rate of Candida among urinary tract infections was 23.9% [22/92]. C. albicans was the most frequent species isolated responsible for fungal urinary tract infections 45.5% [10/22]. However, non-albicans species C. glabrata [22.7%], C. tropicalis [18.2%] and C. krusei [13.7%] were also isolated. Rice agar Tween 80 was found effective in discrimination of Candida species as well as Corn meal agar beside it is cheap and available. CMA medium couldn't identify and discriminate C. glabrata while BIGGY agar showed less sensitivity [36.6%] in discrimination of Candida species compared to the result of morphologic media and API 20C AUX. E-test on [SDA] was found to be an accurate method for antifungal susceptibility as it was compared with the reference broth macrodilution method recommended by National Committee for Clinical Laboratory Standards [NCCLs]. For fluconazole the E-test demonstrated 95.5% agreement at +/- 1dilution and 100% at +/- 2 dilutions for all Candida species. For amphotericin B the E-test demonstrated 86.4% agreement at +/- 1dilution and 90.9% at +/- 2 dilutions for all Candida species. E test revealed that 90.9% and 45.5% of all Candida species were susceptible to amphotericin B and fluconazole respectively. In conclusion non-C. albicans species play a great role as causative agent of fungal urinary tract infections especially in critically ill patients, this necessitate accurate isolation and identification of Candida to the species level and selection of proper antifungal therapy. It is recommended to use morphologic media as Corn meal agar or Rice agar Tween 80 for identification of Candida species and use E-test method on SDA media as a fast simple method for determination of MIC of antifungal drugs, an important point that could encourage clinical laboratories to perform antifungal susceptibility routinely
ABSTRACT
The exact pathophysiology of chronic idiopathic urticaria [CIU] is not well understood. The concept of autoreactivity has evolved to explain the disease in up to 50% of cases, while the search for other mechanisms is still needed to explain the disease, at least among the remaining subpopulation of non-autoreactive CIU. Therefore, we thought to investigate some aspects of the IgE-dependent, lymphocyte-mediated late-phase response [LPR] of anaphylaxis. We searched for percentages of Fc[epsilon]RII-bearing [CD23[+]] B and T lymphocytes and correlated this with total IgE serum levels, IL-4 serum levels and the disease severity scores. Twenty-five patients with non-autoreactive CIU and ten healthy control subjects participated in this study. CD23[+] B- and T-cells were assessed by flow cytometry, total IgE serum levels were estimated by enzyme linked fluorescent assay [ELFA], IL-4 serum levels were estimated by Enzyme Amplified Sensitivity Immunoassay [EASIA], while disease severity was determined by a daily self-assessment urticaria activity and itching score. Our results showed that the mean values for percentages of CD23[+] B-cells [6.7 +/- 2.3%], total IgE serum levels [139.6 +/- 103.9 micro g/dl] and IL-4 serum levels [18.3 +/- 14.7ng/ml] for patients were statistically significant [p=0.002, 0.013 and 0.008, respectively], when compared with the corresponding values for controls [4.0 +/- 1.7%, 51.5 +/- 25.1 micro g/dl, and 5.1 +/- 4.1ng/ml, respectively], while the difference between the mean percentage of CD23[+] T-cells for patients [2.8 +/- 2%] and that for controls [2.1 +/- 0.6%] was nonsignificant [p=0.267]. Strong positive correlations were detected between percentages of CD23[+] B-cells and severity scores [r= 0.678, p= 0.0001], total IgE serum levels [r= 0.756, p= 0.0001] and IL-4 serum levels [r= 0.709, p= 0.0001], while no correlation was detected between CD23[+] B-cells and CD23[+]T-cells [r= 0.188, p= 0.368]. It is concluded, that CD23[+] B-cells, regulated by IL-4, may contribute in the pathogenesis of non-autoreactive CIU, by producing high levels of IgE and possibly lymphokines, while CD23[+] T-cells may be involved in early antigen recognition. This may have a future therapeutic ramification in this distinct subset of CIU by targeting low-affinity IgE receptors