Antimicrobial susceptibility of Brucella melitensis isolates in Peru

Brucellosis is an important public health problem in Peru. We evaluated 48 human Brucella melitensis biotype 1 strains from Peru between 2000 and 2006. MICs of isolates to doxycycline, azithromycin, gentamicin, rifampin, ciprofloxacin, and trimethoprim-sulfamethoxazole were determined by the Etest method. All isolates were sensitive to tested drugs during the periods of testing. Relapses did not appear to be related to drug resistance.     

羊种布鲁氏菌分离株体外抗生素敏感性研究

目的 为研究布鲁氏菌临床分离株常见抗生素的敏感性.方法 本研究利用肉汤稀释法检测布鲁氏菌临床分离株对临床常见布鲁氏菌病治疗药物的最小抑菌浓度(MIC),并利用单因素方差分析比较不同分离省份的菌株药物敏感性差异.结果 在现有的布鲁氏菌耐药拐点下,本研究涉及的布鲁氏菌临床分离株常见治疗药物的MIC均在敏感范围内,其中多西环...     

In vitro susceptibility of clinical isolates of Brucella melitensis to fucidic acid

Brucella species are facultative intracellular bacteria, and therefore a limited number of antibiotics are effective against these organisms. The side effects of drug combination schemes, and the incidences of relapses and therapeutic failures, have led to investigations of new drugs to treat brucellosis. The purpose of this study was to test the in vitro susceptibility of 50 Brucella melitensis isolates to fucidic acid, which has not previously been used for the treatment of brucellosis. The minimum inhibitory concentrations (MICs) of fucidic acid to 50 B. melitensis isolates that were obtained from blood and bone marrow cultures of patients with brucellosis were studied by the broth microdilution method. The MIC₅₀ and MIC₉₀ values for the 50 B. melitensis strains susceptibility to fucidic acid were determined to be 0.5 and 2µg/ml, respectively, and the MIC range was 0.125–2.0µg/ml. Further experiments are needed to reassess the activity of fucidic acid against intracellular Brucella spp.     

Cross-immunity between Brucella melitensis and Mycobacterium tuberculosis; intracellular behavior of Brucella melitensis in monocytes from vaccinated animals

A non-specific element has been demonstrated in the resistance of monocytes derived from immunized rabbits. Vaccination by BCG or by an effective anti-brucellosis reagent induces protection in either case against both Mycobacterium tuberculosis and Brucella melitensis when studied by the monocyte culture method. The activity of the antiserum required to demonstrate the resistance of the monocyte is not affected when the agglutinating action of the anti-Brucella rabbit serum is removed by absorption. The ability of the monocytes from specifically immunized rabbits to retard the growth of virulent Brucella was demonstrated, not as an all-or-none phenomenon, but in the light of the unrestricted bacterial multiplication which occurs in monocytes from normal animals.     

Susceptibilities of Brucella melitensis isolates to clinafloxacin and four other new fluoroquinolones.

The susceptibilities of 120 clinical isolates of Brucella melitensis and 3 reference strains of the same species to six fluoroquinolones (clinafloxacin, PD 117596, PD 131628, PD 138312, PD 140248, and ciprofloxacin) were examined by agar dilution MIC methodology. Clinafloxacin was the most active compound tested (MIC at which 50% of strains tested were inhibited [MIC50] and MIC90 of 0.06 micrograms/ml). Its level of activity was slightly higher than that of PD 117596 (MIC50 and MIC90 of 0.12 micrograms/ml). PD 131628 and ciprofloxacin were less active than clinafloxacin, with MIC50s ranging from 0.12 to 0.25 micrograms/ml and MIC90s of between 0.25 and 0.5 micrograms/ml for the two compounds. The activity levels of PD 138312 and PD 140248, with MIC50s ranging from 1 to 2 micrograms/ml and MIC90s of 4 to 8 micrograms/ml, were lower than those of the other fluoroquinolones tested.     

Characterization of imipenem resistance mechanisms in Pseudomonas aeruginosa isolates from Turkey

The emergence of carbapenem resistance in Pseudomonas aeruginosa threatens the efficacy of this important anti-pseudomonal antibiotic class. Between 2003 and 2006, an increase in the number of carbapenem-resistant P. aeruginosa isolates at the Zonguldak Karaelmas University Hospital was observed (Zonguldak, Turkey). To assess the imipenem resistance mechanisms emerging in these P. aeruginosa isolates, they were characterized by amplified fragment length polymorphism typing, which revealed diversity among imipenem-resistant isolates as well as two clonally related outbreak groups. The molecular mechanism of carbapenem resistance was characterized in a representative isolate from each clonal group. Mutational disruption of oprD was the most frequently encountered resistance mechanism (23/27 isolates).     

Ciprofloxacin resistance in clinical isolates of Salmonella typhimurium obtained from two patients.

Two patients (patients A and B) infected with Salmonella typhimurium failed ciprofloxacin therapy, and the posttherapy isolates had reduced susceptibilities to quinolones; 6 of 11 isolates from patient B were also cross-resistant to chemically unrelated agents. No transferable resistance, chloramphenicol-acetylating enzymes, or beta-lactamases were detected. For 13 of 14 isolates, the concentrations of ciprofloxacin that inhibited DNA synthesis by 50% were similar to the MICs, suggesting a mutation in gyrA. Insertion of pNJR3-2 (gyrA) in the posttherapy isolate from patient A and 5 of 11 of the posttherapy isolates from patient B resulted in lower quinolone MICs, also suggesting that resistance was due to a mutation in gyrA. Three of the five isolates also had reduced levels of accumulation of quinolones. All six cross-resistant isolates from patient B had reduced levels of accumulation of quinolones, but only one isolate had increased susceptibility when pNJR3-2 was inserted. Despite the lack of OmpF seen in five isolates from patient B, there was no correlation with decreased levels of quinolone accumulation. All isolates had identical smooth lipopolysaccharide profiles. The mechanism of apparently reduced accumulation has yet to be determined.     

Surveillance of antimicrobial resistance among gram-negative isolates from intensive care units in eight hospitals in Turkey

With the participation of eight major reference hospitals in Turkey, 749 aerobic Gram-negative isolates obtained from 473 intensive care patients in 1997 were tested for their susceptibility to 13 commonly employed antibacterial agents. The frequency with which species were isolated and resistance rates were compared with data from the previous 2 years. Imipenem was the most active agent against the majority of isolates (75%), followed by ciprofloxacin, cefepime and amikacin. The per cent susceptibility to all antibiotics declined from 1995 to 1996. With the exception of imipenem, for which there was no change in resistance, the per cent susceptibility somewhat increased in 1997. However, it was still lower than in 1995.     

Plasmid-mediated quinolone resistance in isolates obtained in german intensive care units

Screening of 703 isolates of Enterobacteriaceae, obtained from 34 German intensive care units (ICUs), revealed qnr-positive, integron-containing isolates of Enterobacter sp. and Citrobacter freundii from four patients in 2 German ICUs. This is one of the first reports of qnr-positive strains obtained from patients in Europe.     

Intracellular killing of Brucella melitensis in human macrophages with microsphere-encapsulated gentamicin

OBJECTIVES: Treatment of human brucellosis demands antibiotic targeting into the mononuclear-phagocytic system. The aim of this work was to prepare and characterize particulate carriers containing gentamicin and to study their interactions with phagocytic cells and bactericidal activity against intracellular Brucella melitensis. METHODS: Different poly(lactide-co-glycolide) (PLGA) polymers with free carboxylic end-group were used to formulate micro- and nanoparticles containing gentamicin, by a water-oil-water solvent-evaporation technique. PLGA 502H and 75:25H microparticles were selected because they showed the highest gentamicin loadings as well as good physico-chemical properties and sustained release in vitro. RESULTS: Gentamicin-containing microspheres of both polymers were successfully phagocytosed by infected THP-1 human monocytes, and immunocytochemistry studies revealed that the antibiotic reached Brucella-specific compartments. A dose of 30 microg of encapsulated gentamicin was able to reduce intracellular Brucella infection by 2.2 log. CONCLUSIONS: Altogether, these results suggest that 502H and 75:25H microspheres are suitable carriers for gentamicin targeting inside human macrophages and thus for brucellosis treatment.     

National surveillance of antimicrobial resistance in Pseudomonas aeruginosa isolates obtained from intensive care unit patients from 1993 to 2002

Nosocomial infections caused by Pseudomonas aeruginosa in critically ill patients are often difficult to treat due to resistance to multiple antimicrobials. The purpose of this study was to evaluate antimicrobial resistance among P. aeruginosa isolates from intensive care unit patients in the United States from 1993 to 2002 by using the Intensive Care Unit Surveillance Study database. Over the 10-year period, susceptibility of 13,999 nonduplicate isolates of P. aeruginosa was analyzed. From 1993 to 2002, nationwide increases in antimicrobial resistance were greatest for ciprofloxacin, imipenem, tobramycin, and aztreonam. Rates of multidrug resistance (resistance to > or =3 of the following drugs: ceftazidime, ciprofloxacin, tobramycin, and imipenem) increased from 4% in 1993 to 14% in 2002. The lowest dual resistance rates were observed between aminoglycosides or fluoroquinolones with piperacillin-tazobactam while the highest were for those that included beta-lactams and ciprofloxacin. Ongoing surveillance studies are crucial in monitoring antimicrobial susceptibility patterns and selecting empirical treatment regimens.     

Molecular survey of beta-lactamases conferring resistance to newer beta-lactams in Enterobacteriaceae isolates from Polish hospitals

The first national survey of resistance to newer beta-lactams in nosocomial populations of Enterobacteriaceae in Poland was performed. The study covered all nonrepetitive enterobacterial isolates cultured from specimens from inpatients in 13 regional secondary-care hospitals from November 2003 to January 2004. Among 2,388 isolates, the predominant species was Escherichia coli (59.6%), followed by Proteus mirabilis (14.5%) and Klebsiella spp. (8.5%). The frequency of extended-spectrum beta-lactamases (ESBLs) was very high, with ESBLs present in 11.1% of all isolates and 40.4% of Klebsiella pneumoniae isolates, the latter value greatly exceeding that for E. coli (2.5%). The contribution of outbreak isolates was significant, resulting, for example, in a particularly high rate of ESBL producers among Serratia marcescens isolates (70.8%). The pool of ESBL types was overwhelmingly dominated (81.7%) by CTX-M-like beta-lactamases CTX-M-3 (80.6%) and CTX-M-15, with SHV types (17.5%; SHV-2, SHV-5, and SHV-12) and sporadic TEM-like enzymes (0.7%; TEM-19 and TEM-48) being the next most frequent. Acquired AmpC-type cephalosporinases were observed exclusively in P. mirabilis, in 20.5% of the isolates of this species (compared with the frequency of ESBL producers of 11.5% of P. mirabilis isolates). All these cephalosporinases (CMY-12, CMY-15, and a novel variant, CMY-38) originated from Citrobacter freundii. Four isolates of E. coli (two isolates), K. pneumoniae (one isolate), and P. mirabilis (one isolate) produced class A inhibitor-resistant beta-lactamases (TEM-30, TEM-32, TEM-37, and SHV-49), being the first of such producers identified in Poland. The survey documented both specific and more global characteristics of the epidemiology of the beta-lactamase-mediated resistance in enterobacteria from Polish hospitals and demonstrated that the ESBL frequency has reached an alarming level.     

Increasing prevalence of quinolone resistance in human nontyphoid Salmonella enterica isolates obtained in Spain from 1981 to 2003

From January 1981 to December 2003, susceptibility to nalidixic acid was tested in 10,504 nontyphoid Salmonella enterica isolates from patients with acute enteric disease in Gipuzkoa, Spain. The prevalence of nalidixic acid resistance steadily increased from less than 0.5% before 1991 to 38.5% in 2003, mainly due to the increase in resistance among isolates of the most prevalent serovar, S. enterica serovar Enteritidis. For nalidixic acid-resistant isolates, the ciprofloxacin MIC was eightfold higher than that for susceptible isolates, and the nalidixic acid-resistant isolates contained a single point mutation in the gyrA gene (at codons for Ser83 or Asp87). The same mutations were found in a sample of nalidixic acid-resistant nontyphoid Salmonella strains isolated between 1999 and 2003 from retail food for human consumption. In 2003, we identified five S. enterica serovar Typhimurium clinical isolates with high-level fluoroquinolone resistance (ciprofloxacin MIC, 16 microg/ml) with two point mutations in the gyrA gene (coding for Ser83-->Phe and Asp87-->Asn) and one point mutation in the parC gene (coding for Ser80-->Arg). Strict sanitary controls are needed to avoid the spread of ciprofloxacin-resistant serovar Typhimurium isolates, and a more efficient veterinary policy must be adopted to decrease the large burden of Salmonella serovar Enteritidis infections in humans in our region.     

Epidemiological survey of mental disorders in urban regions of Ardabil province (Iran)

For any informed decision making about community-oriented nursing, it is necessary to map out the community regarding the psychological factors. This study is an attempt to estimate the mental disorders' rate among the age group of 15-65 in the urban areas of Ardabil province. A sample of 1430 individuals was selected through random multistage cluster sampling. The instruments employed in this study included Personal Data Questionnaire and the 28-item General Health Questionnaire (GHQ). The findings revealed that, on the whole, 27.83% of the subjects suffer from different mental disorders. The prevalence rate of mental disorders appeared to vary from 13.3% to 44.4% based on the place of residence, and the highest prevalence rate was found to be social dysfunction and anxiety disorders. According to GHQ test, the prevalence rate of social dysfunction, anxiety, somatization and depression disorders were 32%, 22.30%, 20% and 14%, respectively. The study also showed that the prevalence rate of mental disorders was higher among women as compared with men (34.2% vs. 21.1%). The findings of this study is hoped to contribute to community-oriented nursing practice and education.     

2003-2008年儿科临床分离菌的分布变迁及耐药性监测

目的了解目前儿科临床分离细菌种类分布及对抗菌药物的耐药性变化。方法对2003--2008年北京儿童医院住院患儿所有临床分离菌株进行分析,药敏试验使用纸片扩散法和Phoenix100微生物分析仪检测,按CLSI2008年标准进行。使用WHONET5．4软件进行数据的统计分析。结果临床分离革兰阴性菌比率呈上升趋势,革兰阴性菌以大肠埃希菌、铜绿假单胞菌和肺炎克雷伯菌为主。革兰阳性菌以金葡菌、肺炎链球菌和凝固酶阴性葡萄球菌为主。肺炎链球菌是儿科呼吸系统、中枢神经系统和血流感染的重要病原菌,在呼吸道标本中其分离率最高,肺炎链球菌对青霉素不敏感率82．5％。耐甲氧西林凝固酶阴性葡萄球菌（MRCNs）占CNS79．8％～92．7％;MRSA升至10．6％。肺炎链球菌、葡萄球菌和肠球菌均未发现耐万古霉素的耐药株,但有万古霉素中介的肠球菌检出。革兰阴性菌中,产ESBLs大肠埃希菌菌株占73．9％～80．0％;肺炎克雷伯菌为70．5％～81．5％。不发酵糖菌的铜绿假单胞菌对碳青霉烯类抗生素（亚胺培南、美罗培南）耐药率分别为11．3％和9．2％,鲍曼不动杆菌对两者的耐药率均为3．3％。结论儿科临床分离CNS、肺炎链球菌、肠球菌属、大肠埃希菌和克雷伯菌属的耐药处于较高水平,加强儿科临床分离细菌的监测,对于了解儿科临床分离细菌分布及其耐药性变迁,指导临床合理用药防止耐药菌产生和播散都有重要意义。     

我国羊种布鲁氏菌rpoB基因遗传多态性分析

目的 调查中国羊种布鲁氏菌rpoB基因的多态性。方法 利用AMOS-PCR对分离菌株进行种型鉴定;根据布鲁氏菌rpoB基因的4个多态性位点设计特异性引物,对299株羊种布鲁氏菌流行株（羊1型菌38株、羊2型菌19株、羊3型菌242株）的rpoB基因的4个多态性位点进行扩增,并将PCR产物测序结果与羊种布鲁氏菌标准菌株的扩增结果进行比对。结果 羊种布鲁氏菌的rpoB基因检测发现,有169株为rpoB-2变异型、103株为rpoB-2型、24株为新的rpoB基因型（rpoB-4型）及3株为rpoB-1型。结论 我国羊种布鲁氏菌rpoB基因具有较高的多态性,可作为羊种布鲁氏菌的分子流行病学调查靶基因,我国羊种菌rpoB基因型和生物型无相关性。