Streptococci species of anginosus group isolated from oral and maxillofacial infections

The aim of the study was to isolate and identify at species level streptococci strains of anginosus group in pus samples collected from 110 patients with oral and maxillofacial (OMF) infections. Gram-stained smears and cultures on selective and nonselective media were done from each of the 111 pus samples (2 samples were collected from one of the patients, who presented 2 oral abscesses at the same time). The isolates were identified on the basis of cultural and biochemical characteristics. Speciation of the anginosus group isolates was performed using the Rapid ID 32 Strep system (Bio Mérieux, France). Fourty-four anginosus group strains were isolated from 42 patients. Fourty of these isolates were identified as Streptococcus anginosus (2 nonidentical isolates were found in 2 patients), 3 isolates as Streptococcus constellatus and only one as Streptococcus intermedius. The study confirmed that the anginosus group is often involved in OMF infections alone or in association with other aerobic and/or anaerobic bacteria. In the investigated cases, Streptococcus anginosus was by far the most frequently isolated species within the anginosus group.     

Comparison of a randomly amplified polymorphic DNA (RAPD) analysis and ATB ID 32C system for identification of clinical isolates of different Candida species

The objective of this work was to compare the usefulness of a randomly amplified polymorphic DNA (RAPD) assay to that of the ATB ID32C kit (bioMérieux, France) for identification of different species of Candida isolated from clinical specimens. The RAPD-PCR patterns obtained with OPE-18 primer for identification of clinical isolates were consistent, and the different independent assays revealed reproduction of the band patterns. RAPD with the OPE-18 primer is a very specific and sensitive method for identification of Candida glabrata, Candida guilliermondii, Candida tropicalis, Candida pelliculosa, Candida albicans, Candida krusei, and Candida lusitaniae.     

Characterization of the yeast flora present in some Turkish high-sugar products

In this study, 129 Turkish high-sugar products were examined in terms of their yeast flora and 73 representative strains were isolated. Yeast isolates were identified at species level by using Apilab Plus (bioMérieux, France), a specific computer program developed for ID 32C strips (bioMérieux, France). While one of the isolates could be identified at genus level as Aureobasidium, 66 of them were identified as 21 species belonging to 8 different genera. The distribution of these isolates were as follows: Candida (38), Rhodotorula (8), Zygosaccharomyces (7), Cryptococcus (6), Saccharomyces (3), Debaryomyces (2), Pichia (1) and Torulaspora (1). Approximately 70% of the isolates were found to have the ability to grow on media with 50% (w/w) glucose. Hence, they were characterized as xerotolerant strains. Although Zygosaccharomyces rouxii is known as the most xerotolerant yeast species, only two strains of Z. rouxii could be isolated from Turkish high-sugar foods. During identification studies, it was observed that ID 32C test strips should certainly be supported by morphological and physiological tests for obtaining more reliable identification results. If not, closely related yeast species such as anamorph and telemorph forms can not be distinguished.     

Comparison between conventional methods, ChromAgar Candida® and PCR method for the identification of Candida species in clinical isolates

The increase in the incidence of yeast species causing fungemia in susceptible immunocompromised patients in the last two decades and the low sensitivity of conventional blood culture has led to the need to develop alternative approaches for the early detection and identification of causative species. The aim of this study was to compare the usefulness of molecular testing by the polymerase chain reaction (PCR) and conventional methods to identify clinical isolates of different species, using the ID32C ATB system (bioMérieux, France), chromogenic culture Chromagar Candida? (CHROMagar, France) and morphogenesis in corn meal agar. We studied 79 isolates, in which the most prevalent species using the system ID32C and PCR was C. albicans, followed by C. tropicalis, C. glabrata and C .krusei. PCR patterns obtained for the identification of clinical isolates were stable and consistent in the various independent studies and showed good reproducibility, concluding that PCR with species-specific primers that amplify genes ITS1 and ITS2 for rRNA or topoisomerase II primers is a very specific and sensitive method for the identification of C. glabrata, C. krusei, C. albicans, and with less specificity for C. tropicalis.     

Evaluation of fungaemia infections in a Hungarian university hospital between 1996 and 2009

The incidence of Candida species causing bloodstream infections in the University Hospital of Szeged, Hungary, between 1996 and 2009, and the susceptibilities of these isolates to antifungal agents were evaluated.Automated blood culture systems (Vital, bioMérieux, Marcy-l'Etoile, France; and BACTEC 9120, Becton-Dickinson Diagnostic Systems, Sparks, USA) were used. The in vitro susceptibilities of the yeast isolates to antifungal agents were determined by the Etest method (AB Biodisk, Solna, Sweden).Bloodstream infections were caused by yeast strains in 231 cases during this period, and 226 Candida strains were cultured from 216 candidaemia patients. Bloodstream infections caused by multiple Candida spp. were diagnosed almost every year. Of the 216 patients, 67 were children; and 55 infants needed intensive care. In 2005, C. glabrata caused an increase in the incidence of invasive fungal infections in the Neonatal Intensive Care Unit. The PFGE analysis of 12 isolates distinguished 4 different karyotypes. The incidence of bloodstream infections caused by fungi did not change during the 14-year study period. The most frequent species cultured from blood samples were C. albicans and C. glabrata. The incidence of resistant isolates remained constant. The local trends of fungaemia must be monitored and compared with global reports.     

Antimicrobial susceptibility of some streptococci strains of anginosus group isolated from oral and maxillofacial infections

Streptococci strains of the anginosus group isolated from various oral and maxillofacial infections (OMF) were screened for their susceptibility to the following antimicrobial agents: benzylpenicillin, ampicillin, oxacillin, cephalothin, ceftazidime, cefotaxime, cefuroxime, erythromycin, clindamycin, tetracycline, chloramphenicol, vancomycin and trimethoprime-sulphamethoxazole. The isolates were susceptable to: clindamycin, chloramphenicol, vancomycin and all beta-lactam antibiotics, except ceftazidime to which 54.5% of the strains showed intermediate susceptibility. Intermediate susceptibility to tetracycline was found in 11.3% of the strains, whereas resistance to the same antibiotic was demonstrated in 61.4%. Resistance to erythromycin and trimethoprime-sulphamethoxazole was of 2.3% for both. In conclusion, penicillin is the drug of choice in infections caused by streptococci of the anginosus group.     

Distribution and antifungal susceptibility of Candida clinical isolations coming from six health care centers in the metropolitan area of Caracas, Venezuela (years 2003-2005)

The aim of this study was to investigate the frequency and antifungal susceptibility of Candida clinical isolations coming from patients with candidiasis in six health care centers of Caracas, Venezuela metropolitan area. The laboratory reports were retrospectively revised from January 2003 through August 2005. The isolated yeasts identification was carried out by conventional methods and antifungal susceptibility was evaluated by ATB-fungus (bioMérieux, France) and Etest (AB Biodisk, Solna, Sweden). One thousand nine hundred seventy seven (1.977) yeasts were studied and their susceptibility testing were carried out only in 1,414 of them. C. albicans was the most isolated yeast (46.7%) and none-albicans Candida-species represented more than half of the isolations (53.4%). All the isolated yeasts evaluated presented CMIs<1 microg/ml to anfotericina B and showed variable susceptibility percentages to fluconazole (91.5%), itraconazole (80%) and voriconazole (98.6%).     

La Spécificité Parasitaire et ses Incidences sur l'Etiologie et l'Epidémologie des Parasitoses Humaines d'Origine Zoonotique

by J. Euzeby, Fondation Mérieux, 1997. 250.00FFr (153 pages) ISBN 2 84039 053 1.     

High presence of extended-spectrum beta-lactamases and resistance to quinolones in clinical isolates of Escherichia coli

A study was conducted to detect the presence of extended-spectrum β-lactamases (ESBLs) in 706 isolates of Escherichia coli, largely from outpatients (75.2%). The Clinical and Laboratory Standards Institute (formerly NCCLS)-recommended disk diffusion procedure was used to detect ESBL presence; the VITEK 2 system (bioMérieux, Marcy L’Etoile, France) was used to determine the susceptibility to antibiotics of clinical interest, and the ESBLs were characterized by biochemical study, determining the isoelectric point, and by molecular study with PCR. Clonal distribution was studied in eight hospital isolates. There were 115 ESBL-producing isolates (16.3%), with a predominance of CTX-M9 type (58.3%). We draw attention to the high resistance to quinolones (>70%) in CTX-M9 and SHV enzyme producing isolates and the lower aminoglycoside activity in the latter.     

Comparison of cultural methods for the identification and molecular investigation of yeasts from sourdoughs for Italian sweet baked products

Twenty-five yeast strains isolated from sourdough samples for Panettone, Pandoro and Cornetto brioche manufactured by eight different bakeries in northern Italy were characterised. Classification was performed by the simplified identification method (SIM), Kurtzman and Fell's identification protocol, the API system from bioMérieux (France) and the MicroLog system from Biolog (USA). Genetic diversity was investigated by randomly amplified polymorphic DNA fingerprinting and mitochondrial-DNA restriction enzyme analysis. Sequences of the internal transcribed spacers between 18S and 26S rDNA genes were analysed. Candida humilis was the predominant species (56% of isolates), whereas the remaining strains (44%) were related to the Saccharomyces cerevisiae sensu stricto group. Identification systems based on phenotypic analysis proved to be unreliable to identify yeasts from sourdough. Either RAPD-PCR or mtDNA restriction analysis showed to be suitable for the identification of species, but could not be used to differentiate among the isolates at the strain level. Sequencing of the ITS region permitted a consistent classification of the sourdough yeasts.     

Prevalence of oral lesions by Candida sp.: Their varieties and serotypes in a population of patients with AIDS under a highly active antiretroviral therapy.

The aim of this study has been to determine the prevalence of oral candidiasis and oral Candida carriers in an AIDS population under highly active antiretroviral therapy. Eighty-six AIDS patients treated with an antiretroviral combination (indinavir o ritonavir o saquinavir + zidovudine [AZT] + lamivudine [3TC]). Patients were grouped attending the predisposing factors for HIV infection in: intravenous drug users (IDU), heterosexuals, homosexuals, patients using hematological products or having unknown factors. Oral cavity was examined and an oral specimen was inoculated in a chromogenic culture medium (Albicans ID, bioMérieux, France). The prevalence of oral Candida lesions was 30.2% and Candida was isolated from 54.7% of patients. The predominant species was C. albicans serotype A in all the groups with the exception of homosexual patients, were C. albicans serotype B was the predominant. The IDU group showed the higher prevalence of Candida lesions and oral yeasts colonization, followed by the group of heterosexuals and homosexuals. An association was found between the presence of lesions and/or Candida spp. and the clinical stage or the viral concentration. The species Candida dubliniensis was isolated in the oral samples of two patients with candidosis and in two individuals without oral candidosis. The finding of this species in Spanish patients can be added to the data obtained in epidemiological studies in other countries.     

Experimental abscess formation caused by human dental plaque

Human dental plaque consists of a wide variety of microorganisms, some of which are believed to cause systemic infections, including abscesses, at various sites in the body. To confirm this hypothesis experimentally, we examined the abscess-forming ability of native dental plaque in mice, the microbial features of the infectious locus produced by the plaque, and the anti-phagocytic property of microbial isolates. Aliquots of a suspension of supragingival dental plaque containing 6 x 10(6) colony-forming unit of bacteria were injected subcutaneously into the dorsa of mice. Abscess formation was induced in 76 of 85 mice using ten different plaque samples. Thirteen microorganisms were isolated from pus samples aspirated from abscess lesions. The microbial composition of pus, examined in 17 of 76 abscesses, was very simple compared to that of the plaque sample that had induced the abscess. The majority of the isolates belonged to the Streptococcus anginosus group, normally a minor component of plaque samples. S. anginosus was the most frequently detected organism and the most prevalent in seven abscesses, and Streptococcus intermedius and Streptococcus constellatus were predominant in one and three abscess samples, respectively. Each isolate of S. anginosus group produced abscesses in mice, and heat-treated supragingival dental plaque influenced the abscess-forming ability of S. anginosus isolate. These isolates possessed a high antiphagocytic capacity against human polymorphonuclear leukocytes. Our results suggest that human supragingival dental plaque itself is a source of the infectious pathogens that cause abscess formation.     

Nitrogen-fixing sinorhizobia with Medicago laciniata constitute a novel biovar (bv. medicaginis) of S. meliloti

Sixty-eight new rhizobial isolates were obtained from root-nodules of Medicago laciniata and from Mediterranean soils in Tunisia and France. All of them were identified as Sinorhizobium meliloti on the basis of PCR-RFLP analyses of 16S rDNA and the intergenic spacer sequence between 16S and 23S rDNAs. DNA/DNA hybridization, phenotypic characterization and 16S rRNA gene sequencing led to the conclusion that they belong the same taxon. All new isolates shared the ability to nodulate and fix nitrogen with M. laciniata except 11 of them not capable of fixing nitrogen with this plant and originating from French soils containing no efficiently adapted symbionts with M. laciniata. The nitrogen-fixing rhizobia on M. laciniata differed markedly from the other S. meliloti or Sinorhizobium medicae isolates and references in their symbiotic traits such as nifDK RFLP diversity, nodA sequences and nitrogen effectiveness with tree other different annual Medicago species (M. truncatula, M. polymorpha and M. sauvagei). Two infrasubspecific (biovar) divisions are therefore proposed within S. meliloti: bv. medicaginis for Sinorhizobium efficient on M. laciniata and bv. meliloti for the classically known S. meliloti group represented by the strains ATCC9930(T) and RCR 2011 efficient on M. sativa.     

Rapid and reliable identification of Streptococcus anginosus group isolates to the species level by real-time PCR and melting curve analysis

A real-time PCR assay is described for rapid and accurate identification of the Streptococcus anginosus group members. Based on melting curve analysis, the S. anginosus species isolates could be further subdivided into two subgroups, each associated with different clinically relevant ribotypes of S. anginosus.     

Potato late blight in Morocco: characterization of Phytophthora infestans populations (virulence and mating type)

Late blight caused by Phytophthora infestans, is the most important disease of potato in Morocco. Use of partially resistant cultivars should be an essential component of a sustainable management strategy of potato late blight, provided the durability of this form of resistance. It is therefore important to determine the nature of P. infestans Moroccan populations. Mating types were determined for 91 strains of P. infestans collected in the northern (Larache-northern plain), north western (Kénitra) and north eastern (Méknès, Middle Atlas) potato cropping areas of Morocco in 1999-2000, 2000-2001 and 2003-2004. They showed a clear regional structure of these populations, with the presence of both mating types (A1 and A2). Of all isolates collected since 1999, A2 mating type constituted 56% (54 isolates), following by A1 mating type (40.7%, 31 isolates) and A1-A2 (self-fertile) mating type (3.30%, 3 isolates). Populations from Méknès and Kénitra consisted mainly of A2 mating type, whereas populations from Larache predominantly included A1 mating type. Physiological race study revealed the presence of 19 races of P. infestans in the first collection of 25 isolates tested between 1999 and 2001. All known virulence genes were detected in western and northern Moroccan isolates, except virulence for resistance genes R2, R5, and R6 which were absent. All isolates were able to overcome two or more R genes except one isolate (5-1) corresponding to race 1.     

Prevalence of Escherichia coli strains resistance to antibiotics in wound infections and raw milk

Antibiotic-resistant Escherichia coli strains including extended-spectrum β-lactamase (ESBL) isolates are globally widespread in medical, food, and environmental sources. Some of these strains are considered the most pathogenic bacteria in humans. The present work examined the predominance of antibiotic resistance in E. coli strains in wound infections comparing with E. coli strains isolated from a raw milk as a potential source of those strains. The wound infections included abdomen, anus, arm, back, buttock, chest, foot, hand, head, leg, lung, mouth, neck, penis, thigh, toe, and vagina infections. In total, 161 and 153 isolates identified as E. coli were obtained from wound infections and raw milk, respectively. A Vitek 2 system innovated by bioMérieux, France was applied to perform the identification and susceptibility tests. The E. coli isolates that have ability to produce ESBL were detected by an ESBL panel and NO45 card (bioMérieux). Over half of the E. coli were from abdomen, back, and buttock wound infections. More than 50%of the E. coli isolates obtained from wound infections were resistant to cefazolin, ampicillin, cefuroxime, ciprofloxacin, mezlocillin, moxifloxacin, piperacillin, and tetracycline; 70% of the isolates from wound infections and 0% of the isolates from raw milk were E. coli isolates produced ESBL. The data showed that the strains resistance to multi-antibiotic and produced ESBL are more widespread among wound infections than in raw milk.     

Antibiotic resistance and virulence properties of Pseudomonas aeruginosa strains from mechanically ventilated patients with pneumonia in intensive care units: comparison with imipenem-resistant extra-respiratory tract isolates from uninfected patients

We investigated the epidemiology of antibiotic resistance and virulence properties among Pseudomonas aeruginosa clinical isolates collected in 1999 from patients hospitalized in the intensive care units of the centre hospitalier d'Orléans, in France. We compared the totality of the strains from mechanically ventilated patients with pneumonia (33 non-duplicate isolates, group 1) to 15 randomly chosen, imipenem-resistant, extra-respiratory tract isolates, collected from non-infected patients hospitalized in the same units (group 2). The isolates were serotyped, typed by random amplified polymorphic DNA (RAPD), and screened for their pneumocyte cell adherence, cytotoxicity, and antibiotic resistance. A total of 35 RAPD profiles were found, and only two profiles were encountered in both groups, demonstrating a high genetic diversity. 84.8% of the group 1 and 93.3% of the group 2 isolates adhered to A549 cells. Three non-exclusive adhesive patterns were observed: a diffuse adhesion in 38 isolates, a localized adhesion in 14 isolates, and an aggregative adhesion in seven isolates. 78.8% of the group 1 and 93.3% of the group 2 isolates were cytotoxic. Considering all 48 isolates, there was a strong and statistically significant correlation between cytotoxicity and adherence. Among the three dominant serotypes, O:12 isolates were in majority avirulent, but the great majority of O:1 and all the O:11 isolates were found adherent and cytotoxic. Gentamicin was the least active antibiotic for both groups, and ceftazidime was the most active antibiotic for group 1 and amikacin for group 2. The penicillinase production phenotype was significantly correlated with a decrease in P. aeruginosa virulence.     

Utility of albicans ID plate for rapid identification of Candida albicans in clinical samples

Albicans ID (bioMérieux, Marcy l'Etoile, France) is a ready-to-use medium that contains a chromogenic substrate that allows rapid detection and specific identification of Candida albicans. We have evaluated its clinical performance by culturing 846 clinical specimens from pregnant women and neonates. A 99.2% sensitivity and a 100% specificity were observed in the identification of C. albicans isolates from primary culture.     

1235例创伤并发创面感染的病原学调查

目的 调查创伤并发创面感染的细菌分布和耐药现状,为合理使用抗菌药物提供依据.方法 嘉兴市第二医院2005年至2010年1235例创伤并发创面感染的分泌物采用哥伦比亚血琼脂做细菌培养,法国生物梅里埃公司VITEK-32型全自动生物分析仪进行鉴定和药敏.结果 1235例创面感染共培养出细菌1208株.G-杆菌、G+球菌、真菌分别占51.82％、39.57％、8.11％.G-杆菌对头孢类抗菌药物高度耐药,对美洛培南和亚胺培南敏感;G+球菌对β-内酰胺类抗菌药物普遍耐药,对万古霉素、利奈唑烷和莫昔沙星敏感.结论 创伤并发创面感染常见病原菌为铜绿假单胞菌、表皮葡萄球菌、金黄色葡萄球菌、大肠埃希菌、鲍曼不动杆菌,且对抗菌药物多重耐药.     

Antibiotic susceptibility and molecular characterisation of Proteus mirabilis isolates in hospitals from the West Pomeranian area of Poland.

Proteus mirabilis isolates (n = 177), collected between 1996 and 2000 in four hospitals in the West Pomeranian area of Poland, were characterized by antibiotype and pulsed-field gel electrophoresis (PFGE). The selected isolates were collected from different wards (intensive care unit, surgery, internal medicine, and urology). The strains were cultured from various specimen types, mostly from urine, wound samples, bronchial exudates and sputa. The identification was done by biochemical test ID 32E ATB (bioMerieux). Analysis of PFGE patterns was based on comparison of the banding patterns obtained by PFGE of chromosomal DNA digested with SfiI enzyme. Among all P. mirabilis isolates tested three major genotypes A (A1-A7), B (B1-B4), C (C1-C5) and 71 unique patterns were identified. The same genotypes were obtained from different patients, treated in different wards and hospitals during a 5-year period. The strains which belonged to the genotypes A and B were multiresistant and most of them produced ESBL; genotype C was more sensitive to antibiotics.