Prevalence of Pseudomonas aeruginosa O serogroups

The serological typing of 708 P. aeruginosa strains made it possible to determine serogroups in 97.9% of cultures. Serogroups O2 and O6 were the most prevalent (33.8% and 2.5% respectively); serotypes O1, O3 and O11 also occurred rather frequently (about 10%); O4, O7 and O9 were rare (3-8%), serotypes O10 and O12, very rare (less than 1%). The prevalence of P. aeruginosa strains O2 and O6 among the clinical strains was shown over a period of 10 years, serogroup O2 always playing the leading role. In serogroups, the predominance of strains with a definite combination of partial antigen was established; strains with the antigenic structure not described in the International Scheme of the Structure of O-Antigens were detected.     

Difference of Phenotype and Genotype Between Human and Environmental: Isolated Vibrio cholerae in Surabaya,Indonesia

Cholera due to Vibrio cholerae has been spreading worldwide, although the reports focusing on Indonesian V. cholerae are few. In this study, in order to investigate how V. cholerae transmitted to human from environment. We extended an epidemiological report that had investigated the genotype of V. cholerae isolated from human pediatric samples and environmental samples. We examined 44 strains of V. cholerae isolated from pediatric diarrhea patients and the environment such as shrimps or oysters collected in three adjacent towns in Surabaya, Indonesia. Susceptibilities were examined for 11 antibiotics. Serotype O1 or O139 genes and pathogenic genes including cholera toxin were detected. Multi-locus sequence typing (MLST) and enterobacterial repetitive intergenic consensus (ERIC)-PCR were also performed to determine genetic diversity of those isolates. Serotype O1 was seen in 17 strains (38.6%) with all pathogenic genes among 44 isolates. Other isolates were non-O1/non-O139 V. cholerae. Regarding antibiotic susceptibilities, those isolates from environmental samples showed resistance to ampicillin (11.4%), streptomycin (9.1%) and nalidixic acid (2.3%) but those isolates from pediatric stools showed no resistance to those 3 kinds of antibiotics. MLST revealed sequence type (ST) 69 in 17 strains (38.6%), ST198 in 3 strains (6.8%) and non-types in 24 strains (54.5%). All the ST69 strains were classified to O1 type with more than 95% similarity by ERIC-PCR, including all 6 (13.6%) isolates from environmental samples with resistance to streptomycin. In conclusion, V. cholerae O1 ST69 strains has been clonally spreading in Surabaya, exhibiting pathogenic factors and antibiotic resistance to streptomycin, especially in the isolates from environment.     

The prevalence of Yersinia and its serologic variants in patients with acute intestinal diseases of undetermined etiology in Leningrad

Among Yersinia enterocolitica strains of 32 serovars, proposed as typing strains, some strains were found to belong to new species. Y. enterocolitica sensu stricto was represented by 21 serovars in the collection of typing strains. The occurrence of different Yersinia serovars in patients with acute enteric diseases of unknown etiology in Leningrad in 1983-1986 was determined with the use of the set of monoreceptor to 21 serovars. Out of 2,947 cultures studied by biochemical and serological methods, 81% were typed. Among them 18 Y. enterocolitica serovars were determined. Their characteristic feature was the prevalence of serovar O3 and an insignificant proportion of serovar O9. More frequently Yersinia were detected in patients with the primary diagnosis of acute enteric diseases (93.5%). The overwhelming majority (two-thirds) of Yersinia strains were isolated from children. A great number of strains detected in this study (70%) was isolated on days 10-15 of the bacteriological examination. In 927 cultures the following biovars were determined: the strains of serovar O3 belonged to biovar 4 and all other strains, to biovar 1.     

Characterization of Vibrio anguillarum and closely related species isolated from farmed fish in Norway.

A total of 264 bacterial strains tentatively or definitely classified as Vibrio anguillarum were examined. The strains were isolated from diseased or healthy Norwegian fish after routine autopsy. With the exception of five isolates from wild saithe (Pollachius virens), the strains originated from nine different species of farmed fish. The bacteria were subjected to morphological, physiological, and biochemical studies, numerical taxonomical analyses, serotyping by slide agglutination and enzyme-linked immunosorbent assay, DNA-plasmid profiling, and in vitro antimicrobial drug susceptibility testing. The results of the microbiological studies were correlated to anamnestic information. The bacterial strains were identified as V. anguillarum serovar O1 (n = 132), serovar O2 (n = 89), serovar O4 (n = 2), serovar O8 (n = 1), and not typeable (n = 1) as well as Vibrio splendidus biovar I (n = 36) and biovar II (n = 1), Vibrio tubiashii (n = 1), and Vibrio fischerii (n = 1). V. anguillarum serovar O1 or O2 was isolated in 176 out of 179 cases of clinical vibriosis in Atlantic salmon (Salmo salar). V. anguillarum serovar O1 was the only serovar isolated from salmonid fish species other than Atlantic salmon, while V. anguillarum serovar O2 was isolated from all marine fish suffering from vibriosis. A 48-Mda plasmid was isolated from all V. anguillarum serovar O1 isolates examined. Serovar O2 isolates did not harbor any plasmids. Resistance against commonly used antibiotic compounds was not demonstrated among V. anguillarum isolates. Neither V. splendidus biovar I nor other V. anguillarum-related species appeared to be of clinical importance among salmonid fish.(ABSTRACT TRUNCATED AT 250 WORDS)     

Experience with epidemiologic studies of pyocyaneus infections. I. Feasibility of using serotypes and antibiotic resistance as a epidemiologic label for clinical strains]

The authors carried out serological typing of 98 Pseudomonas aeruginosa strains, isolated from patients of burn department of the Sklifosovsky First Aid Institute in January-July, 1974, and of 215 strains obtained from other sources; their sensitivity to 13 antibiotics was determined. Pseudomonas aeruginosa cultures isolated from the patients were typed with O-sera of 10 serological types. The presence of several hospital strains of Pseudomonas aeruginosa was found by means of serological typing; along with these there were revealed cultures of this causative agent sporadically appearing in the department. Sensitivity to some antibiotics could serve as an additional criterion for differentiation of Pseudomonas aeruginosa strains of the same serological type.     

圈养林麝铜绿假单胞菌的分离鉴定及耐药性和病原特性分析

【背景】铜绿假单胞菌感染所致的化脓性疾病是困扰林麝驯养的重要因素,是一类较难防治的细菌性疾病,目前尚无疫苗可用来预防该病。【目的】研究林麝源铜绿假单胞菌的感染现状和分子流行病学规律。【方法】对2014年10月至2015年10月四川宝兴和陕西镇坪两个林麝养殖中心发病林麝中铜绿假单胞菌进行分离鉴定,并对其耐药情况进行分析,利用脉冲场凝胶电泳(PFGE)分型技术研究分离菌的PFGE指纹图谱,探究其流行病学趋势,并对部分菌株的致病性进行分析。【结果】分离得到60株铜绿假单胞菌,其中34株来自镇坪,26株来自宝兴。耐药结果表明:60株林麝源铜绿假单胞菌对17种抗菌药物呈现不同程度耐药性,不同地区和不同样本源间分离的铜绿假单胞菌对17种抗菌药物的耐药性总体趋于一致,多重耐药情况严重,以5耐、6耐为主。分型结果显示:60株铜绿假单胞菌PFGE图谱的相似性为49.1%-100%。经聚类分析得到A-O共15种基因簇,其中优势基因簇为C、E、G、J。致病性结果表明,流行菌株的致病力强弱依次为:动物源菌株环境源菌株,且主要流行菌株(基因簇E、F、J)的致病力大于其余菌群。【结论】铜绿假单胞菌在两地区具有水平传播的途径,本研究可为跨地区林麝化脓性炎症的防控提供理论依据。     

耐喹诺酮类铜绿假单胞菌的耐药性分析及血清学分型

目的了解广州地区喹诺酮类耐药铜绿假单胞菌的耐药性及泵抑制剂对其耐药水平降低的作用,并调查血清型分布情况。方法用法国生物梅里埃公司的微生物鉴定和药敏分析系统VITEK-2对127株铜绿假单胞菌进行鉴定和药敏检测,并采用羰酰氰基-对-氯苯胺(CCCP)与环丙沙星共同作用,以琼脂稀释法测定耐药菌的最低抑菌浓度(M IC)的变化,同时用玻片凝集法对耐药株进行血清学分型。结果环丙沙星耐药菌对哌拉西林/他唑巴坦(65.5%)的敏感率最高,只有阿米卡星(64.4%)、哌拉西林(51.7%)和妥布霉素(50.6%)的敏感率大于50.0%,而敏感菌对美罗培南(97.5%)及左氧氟沙星(97.5%)的敏感率最高,妥布霉素(95.0%)次之,对临床常用的13种抗生素,耐药菌较敏感菌的敏感性明显降低(P值均<0.001);耐药菌受泵抑制CCCP作用,M IC降低1~4个稀释度;血清分型率为93.1%,耐药菌的血清型以B型(20.7%)和L型(19.5%)为主。结论耐喹诺酮类铜绿假单胞菌对临床常用抗生素的敏感性降低,并呈多重耐药,使用抗生素 泵抑制剂可提高药物对铜绿假单胞菌的敏感性;血清学分型可以快速简单地监测铜绿假单胞菌在医院内的流行情况。     

环丙沙星耐药的铜绿假单胞菌药敏情况分析

目的了解对环丙沙星耐药的铜绿假单胞菌的药敏情况。方法细菌的鉴定及药敏试验,均采用法国生物梅里埃公司的VITEK2微生物鉴定与药敏系统,选择经VITEK2测定耐环丙沙星的铜绿假单胞菌(耐药株)68株及对环丙沙星敏感的铜绿假单胞菌(敏感株)67株,统计分析两者对亚胺培南、阿米卡星、庆大霉素、头孢他啶、哌拉西林和哌拉西林他唑巴坦等几种临床上常用抗生素的药敏情况。结果耐药株对以上6种抗生素的敏感率分别为亚胺培南706%,阿米卡星206%,庆大霉素191%,头孢他啶279%,哌拉西林632%,哌拉西林他唑巴坦721%。而敏感株对6种抗生素的敏感率则分别为925%、328%、687%、657%、881%与896%,明显高于耐药株,经χ2检验,除阿米卡星005相似文献   

Occurrence of plasmids in Danish isolates of Vibrio anguillarum serovars O1 and O2 and association of plasmids with phenotypic characteristics.

Two hundred and twenty-eight isolates of Vibrio anguillarum serovar O1 (125 isolates) and serovar O2 (103 isolates) have been characterized with regard to plasmid contents, biochemical properties, and in vitro hemagglutination and hydrophobic properties. Among 74 V. anguillarum isolates from diseased fish, 63 carried only a 67-kb plasmid (pJM1), 9 carried an additional 98-kb plasmid, and 1 isolate carried only the 98-kb plasmid. Only one isolate was without plasmids. In V. anguillarum serovar O1 from nondiseased fish (mucus and gills), plasmids of the same sizes were present in 29 isolates (58%), whereas 21 isolates (42%) were plasmid free. Based on hemagglutination and biochemical properties, V. anguillarum serovar O1 isolates were divided into eight biovars. The plasmid-carrying strains (102 isolates) all fell within biovars 1 and 2, whereas the 23 strains of biovars 3 to 8 were without plasmids. It was tentatively concluded there are two populations of V. anguillarum serovar O1. One population contains plasmid(s), is hemagglutination negative and trehalose negative, and does not form pellicles in broth cultures, whereas the other population is plasmid free and has the opposite characteristics. The former group is the one related to disease in fish. All 20 V. anguillarum serovar O2 isolates from the environment were without plasmids, whereas 54 (65%) of the isolates from fish (trout and cod) carried plasmids. The biochemical diversity within serovar O2 was pronounced; 13 different biovars were demonstrated. No correlation between the presence of plasmids and biochemical properties was observed.     

Occurrence of plasmids in Danish isolates of Vibrio anguillarum serovars O1 and O2 and association of plasmids with phenotypic characteristics.

Two hundred and twenty-eight isolates of Vibrio anguillarum serovar O1 (125 isolates) and serovar O2 (103 isolates) have been characterized with regard to plasmid contents, biochemical properties, and in vitro hemagglutination and hydrophobic properties. Among 74 V. anguillarum isolates from diseased fish, 63 carried only a 67-kb plasmid (pJM1), 9 carried an additional 98-kb plasmid, and 1 isolate carried only the 98-kb plasmid. Only one isolate was without plasmids. In V. anguillarum serovar O1 from nondiseased fish (mucus and gills), plasmids of the same sizes were present in 29 isolates (58%), whereas 21 isolates (42%) were plasmid free. Based on hemagglutination and biochemical properties, V. anguillarum serovar O1 isolates were divided into eight biovars. The plasmid-carrying strains (102 isolates) all fell within biovars 1 and 2, whereas the 23 strains of biovars 3 to 8 were without plasmids. It was tentatively concluded there are two populations of V. anguillarum serovar O1. One population contains plasmid(s), is hemagglutination negative and trehalose negative, and does not form pellicles in broth cultures, whereas the other population is plasmid free and has the opposite characteristics. The former group is the one related to disease in fish. All 20 V. anguillarum serovar O2 isolates from the environment were without plasmids, whereas 54 (65%) of the isolates from fish (trout and cod) carried plasmids. The biochemical diversity within serovar O2 was pronounced; 13 different biovars were demonstrated. No correlation between the presence of plasmids and biochemical properties was observed.     

Nursery Outbreak of Pseudomonas aeruginosa: Epidemiological Conclusions from Five Different Typing Methods

In April 1971, nine cases of Pseudomonas aeruginosa septicemia occurred in a high-risk nursery. The epidemiology of the outbreak was studied by pyocin production, pyocin sensitivity, serological typing, antibiotic susceptibility, and phenotypic properties such as colonial morphology, pigment, and hemolysis. Ten isolates of P. aeruginosa were recovered from 9 newborn infants and from 13 environmental sources. Twenty-one of the 23 isolates had identical pyocin production patterns against 60 different indicator strains and were of the same serotype. These 21 isolates were designated as the "outbreak strain"; the other 2 isolates had no epidemiological significance. The results of pyocin sensitivity, antibiotic susceptibility tests, and phenotypic properties were dissimilar. They would yield incorrect epidemiological conclusions if used alone. The outbreak strain dissociated in vitro and these phenotypic changes accounted for the variable results by the latter three typing methods. Although the precise mode of introduction of the organism into the nursery could not be determined in retrospect, the epidemiological data strongly suggested that one infant contracted a P. aeruginosa infection, and this strain spread throughout the nursery by means of contaminated resuscitation equipment.     

PCR-RAPD typing of carbapenem-resistant Pseudomonas aeruginosa strains

P. aeruginosa rods are opportunistic pathogens responsible generally for nosocomial infections. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to evaluate the usefulness of PCR-RAPD technique in typing of 16 carbapenem-resistant P. aeruginosa strains isolated in 2007 from different patients of University HospitalNo. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Study shows increasing frequency of isolation that type of strains when compared to 2006. Percentage of carbapenem-resistant isolates raised from 12,4% in 2006 to 22.9% in 2007. The majority of examined strains were obtained from patients of the Intensive Care Units (25.0%) and were isolated from bronchoalveolar lavage (25.0%), urine (25.0%) and wound swabs (18.8%) samples. Examined P. aeruginosa strains demonstrated resistance to doripenem (81.3%) and piperacillin (75.0%) and susceptibility to colistin (100.0%), amikacin (81.3%), netilmicin and norfloxacin (75.0% each). Using PCR-RAPD amplification with 208 and 272 primers, 14 and 16 DNA patterns were obtained, respectively. Usefulness of PCR-RAPD in carbapenem-resistant P. aeruginosa strains typing was proved in case of strains presenting similar and/or different antimicrobials susceptibility patterns.     

Epidemiology of Pseudomonas aeruginosa in a Burns Hospital: Evaluation of Serological, Bacteriophage, and Pyocin Typing Methods

In a retrospective study 36 cultures of Pseudomonas aeruginosa, isolated from patients with fatal Pseudomonas burn wound sepsis and from burned patients with nonfatal P. aeruginosa infections, were used to evaluate the consistency and reliability of serological, phage, and pyocin typing as epidemiological tools. Frequency distributions of positive reactions were analyzed by a computer in a 3-way chi-square test, and a high degree of consistency was demonstrated for each method. From these data, 75% of the cultures were differentiated by serological, 90% by phage, and 100% by pyocin typing. There was no significant difference among organisms isolated from fatal cases of burn wound sepsis and organisms from patients with nonfatal infections (chi(2) = 0.3418; P = 0.9870). The combined typing system was a sensitive and reliable epidemiological tool for intraspecific differentiation of P. aeruginosa.     

Ribotypes and plasmid contents of Vibrio anguillarum strains in relation to serovar.

Eighty-six strains of the 10 major agglutination types of Vibrio anguillarum (serovars O1 to O10) and 6 nontypeable strains of V. anguillarum have been characterized by ribotyping with a probe complementary to 16S and 23S rRNA of Escherichia coli and by plasmid profile analysis. Forty-four different ribotypes were observed with the restriction enzyme HindIII. Ribotype similarity was compared by using the Dice coefficient (Sd), and three significantly different levels of homogeneity within the V. anguillarum serovars were observed (serovars O1, O3A, O7, and O9, Sds of > 90%; serovars O2B, O4, and O10, Sds of 80 to 90%; serovars O2A, O3B, O5, and O8, Sds between 46 and 70%). None of the ribotype patterns of V. anguillarum strains were observed among 20 other Vibrio strains typed for comparison. By cluster analysis, the V. anguillarum strains were divided into a main cluster containing 83 strains, while all strains of serovar O3B, one strain (each) of serovars O2A, O5, and O8, and a nontypeable strain were separated from this cluster by at least 15% difference in similarity coefficients. Plasmids were demonstrated in only six strains other than serovar O1. In serovar O1, a 67- to 70-kilobase-pair (kb) plasmid molecule was present in 17 of 19 strains tested; of the two remaining strains, one strain harbored two plasmids (45 and 6.5 kb) and one strain had no plasmids.     

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.     

Prevalence and genotypic relatedness of carbapenem resistance among multidrug-resistant P. aeruginosa in tertiary hospitals across Thailand

ABSTRACT: BACKGROUND: Increased infection caused by multidrug resistant (MDR) Pseudomonas aeruginosa has raised awareness of the resistance situation worldwide. Carbapenem resistance among MDR (CR-MDR) P. aeruginosa has become a serious life-threatening problem due to the limited therapeutic options. Therefore, the objectives of this study were to determine the prevalence, the antibiotic susceptibility patterns and the relatedness of CR-MDR P. aeruginosa in tertiary hospitals across Thailand. METHODS: MDR P. aeruginosa from eight tertiary hospitals across Thailand were collected from 2007--2009. Susceptibility of P. aeruginosa clinical isolates was determined according to the Clinical and Laboratory Standards Institute guideline. Selected CR-MDR P. aeruginosa isolates were genetically analyzed by pulsed-field gel electrophoresis. RESULTS: About 261 clinical isolates were identified as MDR P. aeruginosa and approximately 71.65% were found to be CR-MDR P. aeruginosa. The result showed that the meropenem resistance rate was the highest reaching over 50% in every hospitals. Additionally, the type of hospitals was a major factor affecting the resistance rate, as demonstrated by significantly higher CR-MDR rates among university and regional hospitals. The fingerprinting map identified 107 clones with at least 95% similarity. Only 4 clones were detected in more than one hospital. CONCLUSIONS: Although the antibiotic resistance rate was high, the spreading of CR-MDR was found locally. Specific strains of CR-MDR did not commonly spread from one hospital to another. Importantly, clonal dissemination ratio indicated limited intra-hospital transmission in Thailand.     

Vibrio cholerae O139 bacteriophages

Cholera bacteriophages have been isolated from 27 lysogenic cultures of V. cholerae O139. As shown the pages under study belong to two morphological groups A1 and F1 and serological types II and XII. The use of prophage typing and the sensitivity test to specific phage made it possible to differentiate V. cholerae strains, serogroup O139.     

Phage types and plasmid profiles of plasmid DNA strains of Salmonella enterica subsp. enterica ser. Enteritidis (S. Enteritidis) isolated from food poisoning outbreaks in 2001

Salmonella Enteritidis strains are the most often isolated Salmonella serovar in Poland. In the present study, phage typing, antibiotic resistance testing and plasmid profile analysis, have been applied to characterise 41 Polish S. Enteritidis isolates originated from human cases of salmonellosis and from other sources. The typing phages of Ward and colleagues scheme were used to type a total of 41 S. Enteritidis strains coming from Poland. All 41 strains were typable and 5 different phage types were observed. Among 41 strains tested, both PT6 and PT21 were recognized in the 15 strains (36.6%). Nine strains (22%) belonged to phage type 8. The others PTs were represented by small amount of strains (PT1var and PT4). Among all tested isolates only 4 different plasmid profiles were observed. Of the 41 strains investigated, 16 (39%) contained the 57 kb plasmid alone. The remaining 25 strains (61%) except 57 kb plasmid, possessed additional DNA particles. The probable phage type conversion of PT21 to PT1var strain, possibly connected with smaller DNA particle presence, was observed. This hypothesis needs confirmation. The real S. Enteritidis epidemiological situation in Poland should be known after introducing of systematic, annual research program.     

Contribution of Pseudomonas Aeruginosa strains to infections in patients of specialistic outpatients clinics of the SP ZOZ in Nidzica

The aim of this study was to examine a frequency of isolation and analysis of drug susceptibility o P. aeruginosa strains cultured from clinical specimens obtained from patients treated in specialistic outpatient clinics of the Samodzielny Publiczny Zespó? Opieki Zdrowotnej (SP ZOZ) in Nidzica durin 40 months (01. 09. 2000 - 31. 12. 2003). Ninety six P. aeruginosa strains were cultured out of 829 clinical samples collected from ambulatory patients and processed in the Bacteriological Laboratory of SP ZOZ in Nidzica during over three years. P. aeruginosa strains were isolated from 11.6% of examined specimens. The greatest number of strains (49.0%) were cultured from urine samples obtained from children. Identification of strains was performed using biochemical tests (Becton Dickinson, Emapol, bio-Merieux). Susceptibility of strains to antimicrobial agents was determined with disc diffusion method according to NCCLS recommendations. Special tests were applied to detect extended-spectrum beta-lactamases (ESBL). The most active in vitro against isolated P. aeruginosa strains was a carbapenem - imipenem. All strains were susceptible to this antibiotic. Ciprofloxacin (94.8% of susceptible strains), ceftazidime (89.6%), gentamicin (86.5%), piperacillin (84.4%) and aztreonam (76.0%) were active against the majority of P. aeruginosa strains isolated from ambulatory patients. Six strains (6.25% of all strains) producing extended--spectrum beta--lactamases (ESBL) were detected. It is alarming, that the majority of P. aeruginosa strains from outpatients were cultured out of pediatric samples (61.5%). Because of an increase in resistance and appearance of new mechanisms of resistance to antibiotics/chemotherapeutics in P. aeruginosa strains, it is necessary to monitor a drug susceptibility of these strains causing infections in ambulatory patients.     

Factors associated with virulence and survival in environmental and clinical isolates of Vibrio cholerae O1 and non O1 in Romania

Four hundred ninety seven strains of Vibrio cholerae selected from isolates in Romania in the last decade 1990-1999 were investigated for antibiotic resistance and for classical and putative virulence factors. V. cholerae O1 strains predominated in clinical cases and non O1 strains in the environment, excepting in 1992 when non O1 strains were frequent in clinical and environmental sources. V. cholerae O1 strains previously susceptible to tetracycline acquired clinically significant resistance to this drug during 1993-1994, but this trend was reversed in 1995, following the introduction of nalidixic acid in cholera treatment in 1994. V. cholerae O1 and non O1 clinical isolates acquired simultaneous resistance to the vibriostatic agent O/129 and cotrimoxazole during 1994-1995. High levels of intrinsic resistance to multiple antibiotics were exhibited by all strains examined. The presence of cholera toxin (CT) was concentrated in clinical V. cholerae O1 strains and was substituted in clinical non O1 strains by four putative virulence markers (Kanagawa haemolysin, slime, lipase, and colonial opacity). Colonial opacity (30%) was present only in clinical isolates of V. cholerae non O1. Pigmentogenesis (11.7%) has present only in environmental sources. Antibioresistance profiles differ for V. cholerae O1 and non O1 strains with respect to their source of isolation. This aspect may imply a role in virulence and survival of V. cholerae in the natural environment where they may serve as a reservoir of virulence and multiple drug resistance genes.