Mini-review: Antimicrobial central venous catheters – recent advances and strategies

Central venous catheters (CVCs) nowadays constitute critical devices used in medical care, namely in intensive care units. However, CVCs also represent one of the indwelling medical devices with enhanced risk of nosocomial device-related infection. Catheter-related infections (CRIs) are a major cause of patient morbidity and mortality, often justifying premature catheter removal and an increase in costs and use of resources. Adhesion and subsequent biofilm formation on the surfaces of indwelling catheters is elemental to the onset of pathogenesis. Seeking the prevention of CVC colonisation and CRI, a variety of approaches have been studied, tested and, in some cases, already applied in clinical practice. This review looks at the current preventive strategies often used to decrease the risk of CRIs due to colonization and biofilm formation on catheter surfaces, as well as at the more recent approaches under investigation.     

Carbapenem resistance in Acinetobacter baumannii,and their importance in hospital-acquired infections: a scientific review

Carbapenem is an important therapy for serious hospital-acquired infections and for the care of patients affected by multidrug-resistant organisms, specifically Acinetobacter baumannii; however, with the global increase of carbapenem-resistant A. baumannii, this pathogen has significantly threatened public health. Thus, there is a pressing need to better understand this pathogen in order to develop novel treatments and control strategies for dealing with A. baumannii. In this review, we discuss an overview of carbapenem, including its discovery, development, classification and biological characteristics, and its importance in hospital medicine especially in critical care units. We also describe the peculiarity of bacterial pathogen, A. baumannii, including its commonly reported virulence factors, environmental persistence and carbapenem resistance mechanisms. In closing, we discuss various control strategies for overcoming carbapenem resistance in hospitals and for limiting outbreaks. With the appearance of strains that resist carbapenem, the aim of this review is to highlight the importance of understanding this increasingly problematic healthcare-associated pathogen that creates significant concern in the field of nosocomial infections and overall public health.     

Genome of Staphylococcus xylosus and Comparison with S.aureus and S.epidermidis

Staphylococci are Gram-positive, AT-rich cocci, and often stick together in grape-like clusters. The genus can be classified into two groups based on their ability to produce coagulase, an enzyme that causes clotting of blood plasma （Otto, 2004）. Coagulase-positive Staphylococci include Staphylococcus aureus, a common pathogen of community-acquired and nosocomial infections （Smith et al., 2009）.     

6890例住院病人的医院感染情况调查分析

目的为了了解我院几个重点临床科室住院患者医院感染发病率,以加强控制.方法对医院2002年内利,外利,骨科的6890例住院病历进行调查分析.结果有41例患者医院感染,感染率为0.60%.感染部位:尿道为43.9%,呼吸道为26.8%,手术伤口为19.5%,其它9.8%.感染细菌以G 菌为主,其次是真菌.结论通过监控和加强培训教育能有效地预防医院感染的发生.     

76例恶性肿瘤患者院内深部真菌感染调查

目的探讨深部真菌感染对于恶性肿瘤患者的影响,以及住院期间应注意的问题。方法调查分析2005年1月到2008年12月期间住院的76例恶性肿瘤患者院内深部真菌感染情况,分析患者一般状态、诊治方法的影响。结果76例患者中真菌感染的部位以呼吸道为主（70．9％）,泌尿系次之（17．7％）;病原学检测标本共培养出真菌79株,以白色念珠菌占第1位（60．8％）,热带念珠菌占第2位（21．5％）;老年（≥60岁）、一般状态评分（Ps评分）〉2分、晚期肿瘤差异均有显著性;多数有侵入性操作者（100％）、经过抗生素治疗者（97．4％）、经过激素治疗者（90．8％）和经过放化疗治疗者（82．9％）。结论肿瘤患者的年龄、病情分期、一般状态是本组病例发生院内深部真菌感染的基本病因,抗生素不合理使用及住院期间侵入性操作、既往放化疗及激素治疗等医疗措施是院内深部真菌感染的危险因素。     

Spreading and mechanisms of antimicrobial resistance in microorganisms,producing beta-lactamases. Molecular mechanisms of resistance to beta-lactam antibiotics of <Emphasis Type="Italic">Klebsiella</Emphasis> spp. strains,isolated in cases of nosocomial infections

Antibiotic sensitivity has been investigated in nosocomial bacterial Klebsiella spp. strains isolated from patients treated in 30 hospitals of 15 Russian regions. Among Klebsiella strains (n = 212) studied the following species were found: Klebsiella pneumoniae ss. pneumoniae—182 (85.8%), Klebsiella pneumoniae ss. ozaenae—1 (0.5%), Klebsiella oxytoca—29 (13.7%) strains. Their sensitivity to antibacterial preparations was estimated by the method of serial dilutions in microvolume (the microdilution method). Carbapenems (imipenem and meropenem) exhibited the highest antibacterial activity against the strains studied. Among third generation cephalosporins the lowest MIC (Minimum inhibitory concentration) were found in the inhibitor protected preparations: ceftazidime/clavulanic acid (MIC₅₀ of 0.25 μg/ml; MIC₉₀ of 64 μg/ml) and cefoperazone/sulbactam (MIC₅₀ of 16 μg/ml; MIC₉₀ of 64 μg/ml). Using the PCR method the detection of class A betalactamases genes (TEM, SHV, CTX) was carried out in 42 strains of Klebsiella pneumoniae ss. pneumoniae. TEM type beta-lactamases were found alone or in various combinations in 16 (38.1%) strains, SHV—in 29 (69%), and CTX—in 27 (64.3%). Combinations of 2 and 3 different resistance determinants were detected in 23.8 and 26.2% of strains, respectively. Screening of carbapenem-resistant Klebsiella strains for production of class B metallo-beta-lactamases did not reveal nosocomial strains with phenotypically documented production of these enzymes.     

Comparison of bacteriostatic and bactericidal activity of 13 essential oils against strains with varying sensitivity to antibiotics

Aims:  To compare the bacteriostatic and bactericidal activity of 13 chemotyped essential oils (EO) on 65 bacteria with varying sensitivity to antibiotics.
Methods and Results:  Fifty-five bacterial strains were tested with two methods used for evaluation of antimicrobial activity (CLSI recommendations): the agar dilution method and the time-killing curve method. EO containing aldehydes ( Cinnamomum verum bark and Cymbopogon citratus ), phenols ( Origanum compactum , Trachyspermum ammi , Thymus satureioides , Eugenia caryophyllus and Cinnamomum verum leaf) showed the highest antimicrobial activity with minimum inhibitory concentration (MIC) <2% (v/v) against all strains except Pseudomonas aeruginosa . Alcohol-based EO ( Melaleuca alternifolia , Cymbopogon martinii and Lavandula angustifolia ) exhibited varying degrees of activity depending on Gram status. EO containing 1·8-cineole and hydrocarbons ( Eucalyptus globulus , Melaleuca cajeputii and Citrus sinensis ) had MIC_90% ≥ 10% (v/v). Against P. aeruginosa , only C. verum bark and O. compactum presented MIC ≤2% (v/v). Cinnamomum verum bark, O. compactum , T. satureioides , C. verum leaf and M. alternifolia were bactericidal against Staphylococcus aureus and Escherichia coli at concentrations ranging from to 0·31% to 10% (v/v) after 1 h of contact. Cinnamomum verum bark and O. compactum were bactericidal against P. aeruginosa within 5 min at concentrations <2% (v/v).
Conclusions:  Cinnamomum verum bark had the highest antimicrobial activity, particularly against resistant strains.
Significance and Impact of the Study:  Bacteriostatic and bactericidal activity of EO on nosocomial antibiotic-resistant strains.     

Nosocomial submandibular infections with dipterous fly larvae

In September 1998, a case of nosocomial cutaneous myiasis caused by Lucilia sericata (Meigen, 1826) in a 77-year-old male was found. The patient had been receiving partial maxillectomy due to the presence of malignant tumor on premaxilla. This is the first verified case involving Lucilia sericata in Taegu, Korea. In the present paper, the salient morphological features of the third instar larvae involved have been studied.     

Bronchopneumonia and oral health in hospitalized older patients. A pilot study

Aims: To correlate microbial findings obtained by bronchoalveolar lavage in pneumonia patients with the clinical situation of the oral cavity. Method: Quantitative aerobic and anaerobic cultures were carried out in 150 ml samples of bronchoalveolar lavage (BAL) obtained by means of an endoscope (Video Endoscope Pentax®) inserted per as in the infected bronchus. Material: Twenty consecutive patients with a tentative clinical diagnosis of bronchopneumonia in whom BAL was carried out for diagnostic purposes. A clinical evaluation of the oral health status (oral hygiene, caries, periodontal diseases) was subsequently carried out. Results: In seven edentulous subjects wearing complete dentures the culture of anaerobic microorganisms was negative or yielding less than 100 cfu/ml BAL. Two patients yielded high counts of S. aureus and one high counts of P. aeruginosa. In the 13 subjects with natural teeth left one showed high counts of Veillonella spp. (anaerobic)+P. aeruginosa, one high counts of Veillonella spp. +S. aureus, one high counts of P. aeruginosa + S. aureus and one high counts of E. coli. These four subjects showed poor oral hygiene, periodontal pockets and a BAL microflora consistent with periodontal pathology. Conclusion: The results of this pilot study suggest that microorganisms of denture plaque or associated with periodontal diseases may give rise to aspiration pneumonia in susceptible individuals.     

Phenotypic properties, drug susceptibility and genetic relatedness of Stenotrophomonas maltophilia clinical strains from seven hospitals in Rio de Janeiro, Brazil

AIMS: To investigate phenotypic aspects including biotyping, drug susceptibility and production of extracellular enzymes and genetic diversity of Stenotrophomonas maltophilia clinical strains obtained from seven hospitals in Rio de Janeiro, Brazil. METHODS AND RESULTS: Thirty-nine S. maltophilia strains were investigated by biotying, susceptibility testing, extracellular enzymes detection and by randomly amplified polymorphic DNA (RAPD)-PCR. Biotyping distinguished 13 biotypes among 39, and one of them was prevalent. The majority of the strains produced DNase, gelatinase and haemolysin. Protease, lipases and phospholipase C activities were observed in highly variable amounts. None of the strains was elastase producer. The percentage of full susceptibility, by agar dilution, was 100, 94.8, 81.6 and 26.3% for trimethoprim/sulphametoxazole, ticarcillin/clavulanate, ciprofloxacin and ceftazidime, respectively. Thirty-three RAPD-PCR profiles were obtained suggesting multiple sources of acquisition. CONCLUSIONS: The results pointed out the necessity of monitoring S. maltophilia especially in critical hospital wards, to assure effective control measures. SIGNIFICANCE AND IMPACT OF THE STUDY: Despite of the genetic diversity among the strains, in two situations it was observed indistinguishable RAPD-PCR profiles among strains isolated from different patients who had been hospitalized in the same hospital ward, suggesting the possibility of nosocomial transmission that until now has been rarely related.