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At least 19 recordsLinked to original sources
PubMed2002

Decline in epidemic of multidrug resistant Salmonella typhi is not associated with increased incidence of antibiotic-susceptible strain in Bangladesh.

Since 1987, multidrug resistant (MDR) strains of Salmonella Typhi, resistant simultaneously to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole, have caused epidemics of severe typhoid fever in Asia and Africa. A retrospective analysis of blood culture results (1989-96) in a Diarrhoea Treatment Centre in Dhaka, Bangladesh detected MDR strains in 0.3% (8 of 2793) of samples in 1990. The isolation rate peaked to 3.2% (240 of 7501) in 1994 (P < 0.01) and decreased to 1.8% (165 of 9348) in 1995 and further to 1.0% (82 of 8587) in 1996 (P < 0.01 compared to 1994) indicating the emergence and decline of MDR typhoid epidemic. Ten of 15 MDR strains tested had a 176 kb conjugative R plasmid that mediates resistance to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole to Escherichia coli K12. Unlike MDR strains, the isolation rate (approximately 3.3%) of susceptible S. Typhi remained remarkably unchanged during the study. The significant decrease in isolation of MDR strains suggests that cheaper and effective first-line antibiotics may re-emerge as drugs of choice for the treatment of typhoid fever in Bangladesh.

Adult↗
PubMed2000

Multiple antibiotic resistance in Stenotrophomonas maltophilia: involvement of a multidrug efflux system.

Clinical strains of Stenotrophomonas maltophilia are often highly resistant to multiple antibiotics, although the mechanisms of resistance are generally poorly understood. Multidrug resistant (MDR) strains were readily selected by plating a sensitive reference strain of the organism individually onto a variety of antibiotics, including tetracycline, chloramphenicol, ciprofloxacin, and norfloxacin. Tetracycline-selected MDR strains typically showed cross-resistance to erythromycin and fluoroquinolones and, in some instances, aminoglycosides. MDR mutants selected with the other agents generally displayed resistance to chloramphenicol and fluoroquinolones only, although two MDR strains (e.g., K1385) were also resistant to erythromycin and hypersusceptible to aminoglycosides. Many of the MDR strains expressed either moderate or high levels of a novel outer membrane protein (OMP) of ca. 50 kDa molecular mass, a phenotype typical of MDR strains of Pseudomonas aeruginosa hyperexpressing drug efflux systems. Indeed, the 50-kDa OMP of these S. maltophilia MDR strains reacted with antibody to OprM, the outer membrane component of the MexAB-OprM MDR efflux system of P. aeruginosa. Similarly, a ca. 110-kDa cytoplasmic membrane protein of these MDR strains also reacted with antibody to the MexB component of the P. aeruginosa pump. The outer and cytoplasmic membranes of several clinical S. maltophilia strains also reacted with the anti-OprM and anti-MexB antibodies. N-terminal amino acid sequencing of a cyanogen bromide-generated peptide of the 50-kDa OMP of MDR strain K1385, dubbed SmeM (Stenotrophomonas multidrug efflux), revealed it to be very similar to a number of outer membrane multidrug efflux components of P. aeruginosa and Pseudomonas putida. Deletion of the L1 and L2 beta-lactamase genes confirmed that these enzymes were responsible for the bulk of the beta-lactam resistance of K1385 and its parent. Still, overexpression of the MDR efflux mechanism in an L1- and L2-deficient derivative of K1385 did yield a modest increase in resistance to a few beta-lactams. These data are consistent with the MDR efflux mechanism(s) playing a role in the multidrug resistance of S. maltophilia.

Anti-Bacterial Agents↗
PubMedDate not supplied

Atypical manifestations of typhoid fever.

BACKGROUND: High fever, toxaemia, constipation during first week of fever, complicated by encephalopathy and perforation during third week of fever are the typical manifestations of typhoid fever. However, the classical presentation of typhoid fever has considerably changed now. AIM: To study atypical presentations of typhoid fever. SETTING: A teaching unit of a hospital in South India METHOD: All culture-positive adult patients of typhoid fever admitted over a period of seven years were studied RESULTS: Thirty-two adult patients were admitted. Fifteen (46.9%) patients presented with atypical manifestations. Atypical manifestations observed were burning micturition with normal urine examination (n= 5, 15.6%) diarrhoea in first week (6.2%), encephalopathy in first week (3.1%), isolated hepatomegaly (6.2%), pneumonitis (3.1%) and bone marrow depression (6.2%). Out of 32 Salmonella typhi culture positive patients, 10 (31.3%) patients had multidrug resistant (MDR) strain. Patients with MDR strains had atypical manifestations (5/10=50%) not significantly more often than patients having multidrug sensitive strains (10/22=45.5%) (Z <2). All patients responded to treatment. CONCLUSION: It appears atypical manifestations do not necessarily mean a worse prognosis in typhoid fever. Patients having high fever presenting with pneumonia, early encephalopathy, early diarrhoea or bone marrow depression in a typhoid endemic area, should be suspected for this disease.

Adolescent↗
PubMed1996

Molecular typing of Salmonella typhi strains from Dhaka (Bangladesh) and development of DNA probes identifying plasmid-encoded multidrug-resistant isolates.

Seventy-eight Salmonella typhi strains isolated in 1994 and 1995 from patients living in Dhaka, Bangladesh, were subjected to phage typing, ribotyping, IS200 fingerprinting, and PCR fingerprinting. The collection displayed a high degree of genetic homogeneity, because restricted numbers of phage types and DNA fingerprints were observed. A significant number of the S. typhi strains (67%) were demonstrated to be multiple drug resistant (MDR). The vast majority of the MDR strains were resistant to chloramphenicol, ampicillin, trimethoprim, streptomycin, sulfamethoxazole, and tetracycline (R type CATmSSuT), a resistance phenotype that has also frequently been observed in India. Only two strains displayed a distinct MDR phenotype, R type AT-mSSuT. Pulsed-field gel electrophoresis demonstrated the presence of large plasmids exclusively in the MDR strains of both R types. The plasmids present in the S. typhi strains of R type CATmSSuT could be conjugated to Escherichia coli and resulted in the complete transfer of the MDR phenotype. PCR fingerprinting allowed discrimination of MDR and susceptible strains. The DNA fragments enabling discrimination of MDR and susceptible S. typhi strains by PCR were useful genetic markers for identifying MDR encoded by large plasmids of the H1 incompatibility group.

Bacterial Typing Techniques↗
PubMed1997

Multidrug-resistant Salmonella typhi: a worldwide epidemic.

Since 1989, strains of Salmonella typhi resistant to chloramphenicol, ampicillin, and trimethoprim (i.e., multidrug-resistant [MDR] strains) have been responsible for numerous outbreaks in countries in the Indian subcontinent, Southeast Asia, and Africa. MDR strains have also been isolated with increasing frequency from immigrant workers in countries in the Arabian Gulf, as well as in developed countries from returning travelers. In all MDR strains so far examined, multiple resistance has been encoded by plasmids of the H1 incompatibility group. As a result of the widespread dissemination of such strains, chloramphenicol can no longer be regarded as the first-line drug for typhoid fever. Because strains are also resistant to ampicillin and trimethoprim, the efficacy of these antibiotics has also been impaired, and ciprofloxacin is now the drug of choice for typhoid fever. Chromosomally encoded resistance to ciprofloxacin has now been observed in a small number of strains isolated in the United Kingdom from patients returning from the Indian subcontinent, and in at least one case the patient did not respond to treatment with this antibiotic. It is regrettable that resistance to ciprofloxacin has now emerged in MDR S. typhi, and it is of paramount importance to limit the unnecessary use of this vital drug so that its efficacy should not be further jeopardized.

Developed Countries↗
PubMed1999

[Primary and acquired drug resistance of tuberculosis bacilli in Poland].

Information about resistant pattern of Mycobacterium tuberculosis isolates against antituberculon drugs is a very important part of tuberculosis control and indicates the directions of TB policy in each country. Poland joined WHO/IUATLD global project on drug resistance surveillance, and carried out the first prospective survey, simultaneously on primary and acquired drug resistance of tuberculosis patients according WHO/IUATLD recommendations. The programme covered the whole country, basing on cooperation between the National Reference Laboratory (NRL) with regional TB laboratories. Questionnaires and cultures were obtained from patients who excreted TB bacilli during the period from 1 November 1996 to 1 November 1997 (12 months). Drug susceptibility testing to INH, SM, EMB and RMP were performed on Lowenstein-Jensen medium according to the proportion method or/and radiometric Bactec 460 TB system. 3970 TB patients bacteriologically confirmed by culture were included in a one-year study. The male to female ratio was 2.6:1. Patients were at the age of 6 to 83 years. Majority of patients (86% males and 77% of females) was older than 35 years. Primary resistance to any drug was found in 3.6% of new cases and 2.4% of those patients who excreted monoresistant strains. No monoresistance to EMB was found. 18 patients (0.6%) were infected by MDR strains. Total resistance in new cases was for INH--2.6%, for SM--1.8%, for RMP--0.7% and for EMB--0.1%. Acquired resistance to any drug was found in 17.0% of treated. Majority of patients--7.7% excreted monoresistant strains. 7.0% were infected by MDR strains. Total resistance to INH was 14.8%, to SM--9.2%, to RMP--7.8%, and to EBM--2.5%. No correlation was found between sex and primary resistance rates. Among new cases, 3.7% of males and 3.3% of females were infected with resistant strains. However, among treated patients, males (20%) excreted resistant strains twice as much as females (9.1%). Mean age of women and men infected with primary and acquired resistant strains was similar.

Adolescent↗
PubMed1997

Genome and MIC stability in Mycobacterium tuberculosis and indications for continuation of use of isoniazid in multidrug-resistant tuberculosis.

Mycobacterium tuberculosis strains resistant to two or more of the first line antituberculosis drugs (MDR) are a serious threat to successful tuberculosis control programmes. For this retrospective study, 85 follow-up drug resistant isolates from 23 patients residing in a community with a high incidence of tuberculosis were collected and the level of in-vitro resistance to antibiotics determined quantitatively. PCR-SSCP and sequencing techniques were used to screen for gene mutations associated with resistance in 31 follow-up samples from a smaller group of eight patients. DNA fingerprint analysis was done on sequential isolates to confirm identity. Although treatment had a profound effect on changes in drug resistance patterns, the MIC for a particular agent remained constant in follow-up isolates. DNA fingerprinting and mutational analysis (14 different loci) showed that the genome of MDR strains of M. tuberculosis is relatively stable during the course of therapy. The rpoB gene was the most frequently mutated structural gene involved in drug resistance and a novel C to T mutation upstream of open reading frame (ORF)1 of the inhA operon was detected. No evidence was found of the presence of strain W (New York) in this group of MDR strains. The results stress the importance of confirming individuality of strains for the accurate calculation of frequencies of particular mutations associated with drug resistance, particularly in a high incidence area. Approximately one-half (47.8%) of the patients had isolates resistant to concentrations just above the critical concentration for isoniazid (MICs of 0.2-5 mg/L). Therefore, these patients and their contacts who develop primary drug-resistant tuberculosis may respond to higher dosages of treatment which could have a considerable impact on the cost and the ease of management of resistant tuberculosis.

Antitubercular Agents↗
PubMed2000

Tropical and exotic infections. Proceedings of the 5th Liverpool Tropical School Bayer Symposium on Microbial Diseases. 14 February 1998.

In summary, MDR strains of S. typhi are both epidemic and endemic in many countries in Asia and MDR S. paratyphi A has recently emerged in Pakistan. Multiple clones may be present in a given area at any time. Fluoroquinolones and third generation cephalosporins have been used widely over the past decade to treat MDR strains. The clinical superiority of fluoroquinolones is now threatened by the rapid emergence of chromosomally mediated resistance and cephalosporin resistance is also being reported. Whether these problems can be overcome by the use of newer fluoroquinolones or cephalosporins remains to be seen. Meanwhile, furazolidone and azithromycin deserve further trials, and clinical and molecular surveillance of resistance patterns remains essential.

Cholera↗
PubMed2002

[Frequency of drug resistant tuberculosis in Poland in 2000 as compared to 1997].

Prevalence of drug resistance to one drug and multidrug resistance--MDR in different categories of tuberculosis patients is an important information about the susceptibility pattern of Mycobacterium tuberculosis isolates against antimycobacterial drugs. Poland joined WHO/IUATLD global project on TB drug resistance surveillance, and carried out in 1996/1997 the first prospective survey, simultaneously on primary and acquired drug resistance. This study is repeated in 2000 according to the WHO/IUATLD protocol. The programme covered the whole country. A total of 16 regional centers participated in the co-operative study. 3705 questionnaires and cultures were obtained from patients who excreted TB bacilli during the 12-months from 1 st. January to 31st December 2000. Drug resistance tests to INH, RMP, SM, EMB were performed on Lowenstein-Jensen medium according to the proportion method or/and Bactec 460 TB system. 3705 TB patients (3037 new and 668 treated cases) bacteriologically confirmed by culture were included in one-year study. Primary resistance to any drug was found in 6.12% (CI 5.27-6.56) of new cases. 35 patients (1.15%, CI 0.77-1.35) were infected with MDR strains. Acquired resistance to any drug was found in 16.6% (CI 5.27-6.56), 8.53% (CL 6.41-9.6) of the patients who excreted MDR strains. We have found increased resistance from 3.6% in 1997 to 6.12% (p < 0.001) in 2000 and MDR from 0.6% in 1997 to 1.15% (p < 0.001) in 2000 in untreated tuberculosis patients in Poland. The rate of resistance in the group of treated TB patients was very similar in 1997 (17.0%) and in 2000 (16.6%); except 20% increase of MDR cases--(7.0% in 1997, and 8.53% in 2000). We observed an increase in drug resistant tuberculosis first time during 40 years long period of its monitoring. Regular monitoring of drug resistance in TB patients in Poland is recommended.

Adolescent↗
PubMed1991

Teicoplanin combined with various antibiotics and human blood against a multiple-drug-resistant strain of Staphylococcus aureus.

Neither teicoplanin nor vancomycin at 2, 1 and 0.5 micrograms/ml consistently killed inocula of representative isolates of a multiple-drug-resistant (MDR) strain of Staphylococcus aureus in the presence of 65% (v/v) of fresh, defibrinated human blood, although both antibiotics sterilized tube contents in Mueller-Hinton broth (MHB). With added human blood, teicoplanin (1 microgram/ml) combined with rifampin (1 microgram/ml) was the most effective in vitro combination, followed by teicoplanin (1 microgram/ml) + amoxicillin (8 micrograms/ml) + clavulanate (3 micrograms/ml), ampicillin (8 micrograms/ml) + sulbactam (8 micrograms/ml), cefamandole (8 micrograms/ml), fosfomycin (4 micrograms/ml + 25 micrograms/ml glucose-6-phosphate), imipenem (8 micrograms/ml), netilmicin (4 micrograms/ml), trimethoprim + sulfamethoxazole (1/19 micrograms/ml) and vancomycin (1 microgram/ml), respectively. Conversely, teicoplanin (1 microgram/ml) combined with fusidic acid (0.5 micrograms/ml) and ofloxacin (4 micrograms/ml), respectively, proved ineffective with 65% (v/v) added human blood. In concurrent control tubes, however, all drug combinations were bactericidally active in MHB against the MDR strain of S. aureus.

Aminoglycosides↗
PubMed1996

Therapeutic aspects of typhoidal salmonellosis in childhood: the Karachi experience.

We evaluated the response to therapy in a series of 876 children consecutively admitted to The Aga Khan University Hospital with culture-proven typhoid, including 281 cases infected with multi-drug-resistant (MDR) strains. Among sensitive isolates there was no significant difference in cure rates, failure rates and time to defervescence with either ampicillin or chloramphenicol. Of the 217 children with MDR typhoid who received therapy with third-generation cephalosporins, the outcome was significantly better with intravenous ceftriaxone compared with cefotaxime. Despite comparable cure rates, the time to defervescence was significantly longer among MDR strains treated with ceftriaxone versus sensitive strains (mean (SD): 7.2 (3.4) versus 6.3 (29) days; p < 0.05). Earlier recognition and introduction of appropriate second-line therapy has allowed us to reduce the case fatality rates of typhoid to under 1%. Although a 14-day course of ceftriaxone can be used successfully to treat most children hospitalized with MDR typhoid, there is a need to evaluate the role of short-course therapy or alternative therapeutic agents.

Algorithms↗
PubMed1999

The threat of multidrug-resistant tuberculosis: results of 1 yr of surveillance in the Lombardy region of Italy.

A descriptive multicentre study based on laboratory data was carried out in patients with culture-confirmed tuberculosis (TB) who were cared for between September 1995 and August 1996 in 14 general hospitals with at least one human immunodeficiency virus (HIV) ward, a hospital specializing in TB or a large chest clinic, all in the Lombardy region of Italy. For each culture positive for Mycobacterium tuberculosis, the results of susceptibility tests to the five first-line anti-TB drugs were collected; other information collected included: the patient's name, the ward/service where the patient was staying and the characteristics of the culture (biological sample, date of arrival and type of mycobacterium isolated). Foreign-born persons were identified through their names; acquired immune deficiency syndrome (AIDS) patients were identified through record linkage with the National AIDS Registry. Given that only one-quarter of the laboratories performed pyrazinamide-susceptibility tests, resistance to this drug was not analysed. Of the isolates tested, 28.1% were resistant to at least one drug, i.e. single-drug-resistant (SDR) and 12.9% were multidrug-resistant (MDR). The frequency of SDR and MDR strains showed considerable variation by healthcare centre (range 0.0-94.3% and 0.0-37.1%, respectively). In three hospitals, the time of occurrence and the susceptibility pattern of the MDR-TB isolates indicated that clusters of the disease occurred. The frequency of both SDR and MDR strains was significantly higher among AIDS patients (48.8% and 23.6%, respectively) than among foreign-born persons (30.2% and 6.9%) or persons belonging to no known risk group (98.3% and 11.3%). The frequency of drug resistance observed in this study is much higher than that reported in other European surveys and is comparable only to that observed in New York, before the implementation of an effective control programme. Acquired immune deficiency syndrome patients are at very high risk of multidrug-resistant tuberculosis: effective containment and infection control practices should be rigorously implemented to prevent the occurrence of this alarming phenomenon.

Antitubercular Agents↗
PubMedDate not supplied

The changing face of the epidemiology of tuberculosis due to molecular strain typing--a review.

About one third of the world population is infected with tubercle bacilli, causing eight million new cases of tuberculosis (TB) and three million deaths each year. After years of lack of interest in the disease, World Health Organization recently declared TB a global emergency and it is clear that there is need for more efficient national TB programs and newly defined research priorities. A more complete epidemiology of tuberculosis will lead to a better identification of index cases and to a more efficient treatment of the disease. Recently, new molecular tools became available for the identification of strains of Mycobacterium tuberculosis (M. tuberculosis), allowing a better recognition of transmission routes of defined strains. Both a standardized restriction-fragment-length-polymorphism-based methodology for epidemiological studies on a large scale and deoxyribonucleic acids (DNA) amplification-based methods that allow rapid detection of outbreaks with multidrug-resistant (MDR) strains, often characterized by high mortality rates, have been developed. This review comments on the existing methods of DNA-based recognition of M. tuberculosis strains and their peculiarities. It also summarizes literature data on the application of molecular fingerprinting for detection of outbreaks of M. tuberculosis, for identification of index cases, for study of interaction between TB and infection with the human immuno-deficiency virus, for analysis of the behavior of MDR strains, for a better understanding of risk factors for transmission of TB within communities and for population-based studies of TB transmission within and between countries.

Humans↗
PubMed2002

Cloning and expression of functional shikimate dehydrogenase (EC 1.1.1.25) from Mycobacterium tuberculosis H37Rv.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, continues to be one of the deadliest diseases in the world. TB resurged in the late 1980s and now kills more than 2 million people a year. Possible factors underlying the reemergence of TB are the high susceptibility of human immunodeficiency virus-infected persons to the disease, the proliferation of multi-drug-resistant (MDR) strains, patient noncompliance in completing the standard "short-course" therapy, and decline of health care systems. Thus, there is a need for the development of new antimycobacterial agents to treat MDR strains of M. tuberculosis, to provide for more effective treatment of latent tuberculosis infection, and to shorten the treatment course to improve patient compliance. The shikimate pathway is an attractive target for antimicrobial agents development because it is essential in algae, higher plants, bacteria, and fungi, but absent in mammals. Homologs to enzymes in the shikimate pathway have been identified in the genome sequence of M. tuberculosis. The M. tuberculosis aroE-encoded shikimate dehydrogenase was PCR amplified, cloned, sequenced, and expressed in Escherichia coli BL21(DE3). Recombinant protein expression was achieved by a low-cost and simple protocol. Although cell lysis resulted in the formation of insoluble aggregates of the recombinant protein, soluble and functional M. tuberculosis shikimate dehydrogenase could be obtained by repeated cycles of freezing and thawing. Enzyme activity measurements demonstrated that there was approximately a 5-fold increase in specific activity for M. tuberculosis shikimate dehydrogenase. Moreover, the enzyme activity was linearly dependent upon the amount of recombinant protein added to the assay mixture, thus, confirming cloning and expression of functional mycobacterial shikimate.

Alcohol Oxidoreductases↗
PubMed1996

[Resistant lung tuberculosis in Berlin 1987-1993].

Resistance of Mycobacterium tuberculosis (M. tb) strains is an increasing problem worldwide. Since no public health data are available for urban populations in Germany, we investigated resistance in our hospitalized patients (n = 1011) during the last seven years. We evaluated clinical data and results of susceptibility tests (break-point technique/proportion method) for isoniazid, streptomycin, rifampin, pyrazinamide, protionamide, and ethambutol. Since 1987 there has been a relatively constant rate of 5.9% (3.9-7.8%) for single-drug resistance (SDR) but an increasing rate of multidrug-resistant (MDR) strains (> or = 2 first-line drugs) from 1.7% in 1987 to 5.8% in 1993. 69% of patients with MDR strains showed resistance to two drugs and 31% to three or more drugs. Risk factors for SDR and MDR tuberculosis revealed previous therapy (odds ratio (OR) [CI95%] SDR: 2.2 [1.7-4.0]; MDR: 4.5 [2.3-8.8]) and foreign-born status (SDR: 2.2 [1.3-3.6]; MDR: 3.5 [1.8-6.8]) to be the most important factors associated with resistance (p < 0.006-0.0001). Both primary and acquired resistance was higher in foreign-born than in German-born patients (p < 0.005). There was a considerable increase in multidrug-resistant tuberculosis in our hospital during 1987 and 1993. Since previously treated patients and patients born in countries with a high level of primary resistance had an increased risk of drug-resistant tuberculosis, we would advise a four-drug regimen as initial therapy in those patients.

Adolescent↗
PubMed1995

Drug-resistant pulmonary tuberculosis in Berlin, Germany, 1987-1993.

Resistance of Mycobacterium tuberculosis (M.tb) strains is an increasing problem worldwide. Since no public health data are available for urban populations in Germany, we investigated resistance in our hospitalized patients (n = 1,011) over the last 7 yrs. We therefore evaluated clinical data and results of susceptibility tests (breakpoint technique/proportion method) for isoniazid, streptomycin, rifampin, pyrazinamide, protionamide and ethambutol. Since 1987, there has been a relatively constant rate of 5.9% (3.9%-7.8%) for single-drug resistance (SDR), but an increasing rate of multidrug-resistant (MDR) strains (> or = 2 first-line drugs) from 1.7% in 1987 to 5.8% in 1993. Sixty nine percent of patients with MDR strains showed resistance to two drugs, and 31% to three or more drugs. Risk factors for SDR and MDR tuberculosis revealed previous therapy (odds ratio (OR) (95% confidence interval (95% CI)); SDR 2.2 (1.7-4.0); MDR 4.5 (2.3-8.8)); and foreign-born status (SDR 2.2 (1.3-3.6); MDR 3.5 (1.8-6.8)) to be the most important factors associated with resistance. Both primary and acquired resistance were higher in foreign-born than in German-born patients. We conclude that there was a considerable increase in multidrug-resistant tuberculosis in our hospital from 1987 to 1993. Since previously treated patients and patients born in countries with a high level of primary resistance had an increased risk of drug-resistant tuberculosis, we would advise a four drug regimen as initial therapy in those patients.

Adult↗
PubMed2002

Molecular characterization of cephalosporin-resistant Salmonella enterica serotype Newport isolates from animals in Pennsylvania.

Multidrug-resistant (MDR) strains of Salmonella enterica serotype Newport have been described for many years. However, the recognition of Newport strains with resistance to cephalosporin antibiotics is more recent. Plasmid-mediated CMY-2 AmpC beta-lactamases have been identified in Salmonella in the United States, and the bla(CMY-2) gene has been shown to be present in Salmonella serotype Newport. This organism is currently undergoing epidemic spread in both animals and humans in the United States, and this is to our knowledge the first description of the molecular epidemiology of this Salmonella strain in animals. Forty-two isolates were included in this study. All isolates were characterized by pulsed-field gel electrophoresis, plasmid analysis, and antibiogram. Four pulsed-field profiles with XbaI were observed. Plasmid analyses showed that although the majority of isolates harbored a single plasmid of 140 kb, this plasmid was not identical in all strains. All isolates showed the presence of the bla(CMY) gene by PCR. Integrons were detected in 16 of the 42 isolates; a fragment of approximately 1,000 bp, amplified with the intI-F and aadAI-R primers, confirmed the presence of the aadAI gene cassette within an integron in these 16 isolates. The potential for coselection of the bla(CMY) gene, if located on an MDR replicon, may not be dependent on any particular antibiotic but rather may be the result of more general antimicrobial use. If this replicon is mobile, it is to be expected that similar MDR strains of additional Salmonella serotypes will be recognized in due course.

Animals↗
PubMed2002

[Infectiousness and virulence of multidrug-resistant and drug susceptible tuberculosis in adult contacts].

Patients carrying multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have been considered traditionally as presenting a diminished epidemiological risk according to animal experimentation results. The experience obtained from the MDRTB/AIDS related epidemics showed MDRTB transmission to immunocompetent health care workers and adults close contacts. In this retrospective study, the infectiousness (measured as the frequency of intradermal test with PPD 2TU over 10 mm) and virulence (cases bacteriologically confirmed) among close contacts of patients with MDR and susceptible TB were evaluated. A total of 97 contacts of 37 MDRTB patients vs. 356 contacts of 100 patients with susceptible TB were studied. No statistical differences were found in PPD 2 UT positivity and TB cases between both contact groups, nor in relation to HIV seropositivity of index cases. According to these observations, MDR strains of M. tuberculosis present similar infectiousness and virulence compared with susceptible strains.

Adult↗