Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Antibiogram”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed1992

Antimicrobial susceptibility testing of Bilophila wadsworthia by using triphenyltetrazolium chloride to facilitate endpoint determination.

Initial susceptibility studies of Bilophila wadsworthia indicated significant resistance to several beta-lactam antibiotics, including imipenem and cefoxitin. NO beta-lactamase production was detected. However, some B. wadsworthia strains may grow as a heavy "haze" at up to the highest concentration of an antibiotic on standard antimicrobial agent-containing plates, and it is often difficult to determine the point at which conventional growth stops and haze growth begins. We investigated the nature of the haze growth of B. wadsworthia by using triphenyltetrazolium chloride (TTC) as an indicator of viability during antimicrobial susceptibility testing, by determining viability counts on antimicrobial agent-containing plates at various times, and by microscopically inspecting stained preparations of the growth on the control plate and the haze area. TTC MICs were determined by applying a TTC solution over the growth on plates inside the anaerobic chamber or within 5 min after exposure to air (aerobic TTC MICs). The haze growth reduced TTC in the chamber but not under aerobic conditions, whereas TTC was reduced by the conventional growth in both atmospheres. The aerobic TTC MICs correlated with the viability counts. Separated proteins resolved by polyacrylamide gel electrophoresis and isoelectric focusing showed TTC-reactive bands only when stained under anaerobic conditions, further demonstrating the sensitivity of TTC reduction to aerobic conditions. Microscopic examination of the haze growth indicated spheroplast formation. A new antibiogram for B. wadsworthia has been established by use of aerobic TTC endpoints; we believe that the lower MICs obtained with the TTC method are likely the ones that are clinically relevant and should be used in tests of B. wadsworthia. Also, we found that when the organisms were grown on pyruvate-containing medium, 87% of 56 strains tested were Beta-lactamase positive.

Anti-Bacterial Agents↗
PubMed1992

Resistance to cefotaxime and seven other beta-lactams in members of the family Enterobacteriaceae: a 3-year survey in France.

During the second quarter each of 1988, 1989, and 1990, a French collaborative study group, including 12 university hospital laboratories, surveyed the resistance to beta-lactams of clinical isolates from hospitalized patients: consecutively, 10,641, 10,692, and 9,382 isolates were tested. The distribution of bacterial species over time was similar in each laboratory. The susceptibilities of microorganisms to amoxicillin, ticarcillin, cephalothin, cefoxitin, cefotaxime (CTX), ceftazidime (CAZ), aztreonam (ATM), and imipenem (IPM) were measured by the disk diffusion method in accordance with the recommendations of the Antibiogram Committee of the French Society for Microbiology. Five reference strains were included for quality control. Extended-spectrum beta-lactamases were detected by the synergistic effect of the combination of clavulanic acid-amoxicillin with CTX, CAZ, and ATM in the double-diffusion test. A synergistic effect with CTX, CAZ, and ATM was detected for 1.5% of all strains, mainly those of Klebsiella pneumoniae (13.3%). For this species, the synergy test enabled the detection of roughly 50% of the resistant strains misclassified as susceptible on the basis of interpretative standards. Extended-spectrum beta-lactamases disseminated in 1990 in most enterobacterial species but at a low frequency. Important variations in the percentages of resistant strains were observed in terms of bacterial species, hospitals, and wards. However, when the total number of strains was considered, the percentages of resistance to newer beta-lactams remained low.

Anti-Bacterial Agents↗
PubMed1996

Effects of topical erythromycin on ecology of aerobic cutaneous bacterial flora.

We have demonstrated previously that application of topical erythromycin, an antibiotic commonly used for the treatment of acne, results in an increased density of cutaneous erythromycin-resistant (Emr) coagulase-negative staphylococci; however, it is unknown if this increase results in an overall higher density of total cutaneous staphylococci or if upon cessation of erythromycin use, Emr coagulase-negative staphylococci remain at an increased density compared with the pretreatment density. To investigate this, 2% erythromycin or vehicle was applied to each subject's forehead (n = 225) twice a day by laboratory personnel for a period of 6 weeks. Samples were obtained for culture from the forehead, anterior nares, and back of the subjects at baseline and at weeks 6, 9, and 12 of the study. Cultures were performed on differential media. Plates into which erythromycin was incorporated (8 micrograms/ml) were used to identify Emr coagulase-negative staphylococci. The species of all Emr coagulase-negative staphylococci were determined, and an antibiogram for 16 antibiotics was obtained. The baseline prevalence of Emr coagulase-negative staphylococci on the forehead and nose was about 80% at the two study sites, whereas that on the back was 50%. The baseline density of Emr coagulase-negative staphylococci on the forehead, nose, and back was approximately 20% of the total flora. Following 6 weeks of erythromycin treatment, the prevalence of Emr coagulase-negative staphylococci on the forehead and nose was nearly 100% and the densities were 73 and 62%, respectively; the prevalence and density for the back were 78 and 42%, respectively. The most prevalent erythromycin resistance gene expressed by the Emr coagulase-negative staphylococci was ermC. There was no increase in the numbers of Staphylococcus aureus, gram-negative rods, or yeasts, nor was there increased resistance to any other antibiotic except clindamycin. The density of total aerobic organisms also remained static. There were no changes in the prevalence or density of Emr coagulase-negative staphylococci in the vehicle group. A statistically significant decrease in the prevalence and density of Emr coagulase-negative staphylococci in the erythromycin group was observed within 3 weeks posttreatment and by 6 weeks posttreatment, the prevalence and density returned to baseline values. These data demonstrate that the increased prevalence and density of Emr coagulase-negative staphylococci as a result of topical 2% erythromycin use are transient on both population and individual levels.

Administration, Topical↗
PubMed1999

OXA-17, a further extended-spectrum variant of OXA-10 beta-lactamase, isolated from Pseudomonas aeruginosa.

Pseudomonas aeruginosa isolates 871 and 873 were isolated at Hacettepe University Hospital in Ankara and were highly resistant to ceftazidime (MIC, 128 microg/ml). Each produced three beta-lactamases, with pIs of 5.3, 6.1, and 7.9. The beta-lactamase with a pI of 5.3 was previously shown to be PER-1 enzyme. The antibiograms of the isolates were not entirely explained by production of PER-1 enzyme, insofar as ceftazidime resistance was incompletely reversed by clavulanate. The enzymes with pIs of 6.1 and 7.9 were therefore investigated. The enzyme with a pI of 6.1 proved to be a novel mutant of OXA-10, which we designated OXA-17, and had asparagine changed to serine at position 73 of the protein. When cloned into Escherichia coli XL1-blue, OXA-17 enzyme conferred greater resistance to cefotaxime, latamoxef, and cefepime than did OXA-10, but it had only a marginal (two- to fourfold) effect on the MIC of ceftazidime. This behavior contrasted with that of previous OXA-10 mutants, specifically OXA-11, -14, and -16, which predominately compromise ceftazidime. Extracted OXA-17 enzyme had relatively greater activity than OXA-10 against oxacillin, cloxacillin, and cefotaxime but, in terms of kcat/Km, it had lower catalytic efficiency against most beta-lactams. The enzyme with a pI of 7.9 was shown by gene sequencing to be OXA-2.

Anti-Bacterial Agents↗
PubMed2001

Complexity and diversity of Klebsiella pneumoniae strains with extended-spectrum beta-lactamases isolated in 1994 and 1996 at a teaching hospital in Durban, South Africa.

beta-Lactamase production was investigated in cultures of 25 Klebsiella pneumoniae isolates isolated at a hospital in Durban, South Africa, in 1994 and 1996. Twenty of these isolates gave ceftazidime MIC/ceftazidime plus clavulanate MIC ratios of >/=8, implying production of extended-spectrum beta-lactamases (ESBLs), and DNA sequencing identified an ESBL gene (bla(TEM-53)) in a further two isolates. Pulsed-field gel electrophoresis (PFGE) defined 4 distinct strains among the 12 isolates collected in 1994 and 9 distinct strains among the 13 isolates collected in 1996. In three cases, multiple isolates from single patients varied in their PFGE profiles and antibiograms, implying mixed colonization or infection. Isoelectric focusing and DNA hybridization found both TEM and SHV enzymes and their genes in all 25 isolates. Many isolates had multiple identical or different beta-lactamase gene variants, with at least 84 bla(SHV) and bla(TEM) gene copies among the 25 organisms. Sequencing identified the genes for the SHV-1, -2, and -5 enzymes and for four new SHV types (SHV-19, -20, -21, and -22). These new SHV variants had novel mutations remote from sites known to affect catalytic activity. Sequencing also found the genes for TEM-1, TEM-53, and one novel type, TEM-63. All the isolates had multiple and diverse plasmids. These complex and diverse patterns of ESBL production and strain epidemiology are far removed from the concept of an ESBL outbreak and suggest a situation in which ESBL production has become endemic and in which evolution is generating a wide range of enzyme combinations. This complexity and diversity complicates patient management and the design of antibiotic use policies.

Amino Acid Substitution↗
PubMed2002

High prevalence of oxacillin-resistant Staphylococcus aureus isolates from hospitalized patients in Asia-Pacific and South Africa: results from SENTRY antimicrobial surveillance program, 1998-1999.

As part of the SENTRY antimicrobial surveillance program, we examined the prevalence rates, types, and antibiograms of oxacillin-resistant Staphylococcus aureus from hospitalized patients from 17 institutions in eight countries in Asia-Pacific and South Africa (APAC). From April 1998 to December 1999, a total of 1,711 isolates of S. aureus (814 from blood, 392 from the respiratory tract, 467 from skin and skin structures, and 38 from urine) were collected from hospitalized patients within the APAC region. Multidrug-resistant oxacillin-resistant S. aureus (MORSA) isolates, defined as strains with three or more resistances to drug classes other than beta-lactams, were the most common type of oxacillin-resistant S. aureus (ORSA). They were the most frequently identified pathogen in wound infections and were common in bloodstream and lower respiratory tract infections. In all contributing institutions combined, more than 45% (range, 4 to 74%) of S. aureus isolates were oxacillin resistant, and in six institutions, this rate exceeded 60%. MORSA accounted for 91.2% of all oxacillin-resistant isolates. Distinct resistance patterns predominated at various sites within the APAC region, suggesting the local evolution of resistant clones. Non-multidrug-resistant strains were frequent in one part of Australia. No vancomycin-intermediate strains were detected, and no strains were resistant to linezolid or quinupristin-dalfopristin. MORSA strains are a very common cause of infection in hospitalized patients in the APAC region.

Asia↗
PubMed1998

Detection of Escherichia coli O157:H7 in the beef marketed in Malaysia.

Twelve strains of Escherichia coli O157:H7 were isolated from 9 of 25 beef samples purchased from retail stores in Malaysia. These strains produced Shiga toxin 2 with or without Shiga toxin 1 and had the eae gene and a 60-MDa plasmid. The antibiograms and the profiles of the arbitrarily primed PCR of the strains were diverse, suggesting that the strains may have originated from diverse sources.

Animals↗
PubMed2000

Molecular characterization of Irish Salmonella enterica serotype typhimurium: detection of class I integrons and assessment of genetic relationships by DNA amplification fingerprinting.

Salmonella enterica is among the principal etiological agents of food-borne illness in humans. Increasing antimicrobial resistance in S. enterica is a cause for worldwide concern. There is concern at present in relation to the increasing incidence of human infection with antimicrobial agent-resistant strains of S. enterica serotype Typhimurium, in particular of phage type DT104. Integrons appear to play an important role in the dissemination of antimicrobial resistance genes in many Enterobacteriaceae including S. enterica. In this study the antimicrobial susceptibilities and phage types of 74 randomly collected strains of S. enterica serotype Typhimurium from the Cork region of southern Ireland, obtained from human, animal (clinical), and food sources, were determined. Each strain was examined for integrons and typed by DNA amplification fingerprinting (DAF). Phage type DT104 predominated (n = 48). Phage types DT104b (n = 3), -193 (n = 9), -195 (n = 6), -208 (n = 3), -204a (n = 2), PT U302 (n = 1), and two nontypeable strains accounted for the remainder. All S. enterica serotype Typhimurium DT104 strains were resistant to ampicillin, chloramphenicol, streptomycin, Sulfonamide Duplex, and tetracycline, and one strain was additionally resistant to trimethoprim. All DT104 strains but one were of a uniform DAF type (designated DAF-I) and showed a uniform pattern of integrons (designated IP-I). The DT104b and PT U302 strains also exhibited the same resistance phenotype, and both had the DAF-I and IP-I patterns. The DAF-I pattern was also observed in a single DT193 strain in which no integrons were detectable. Greater diversity of antibiograms and DAF and IP patterns among non-DT104 phage types was observed. These data indicate a remarkable degree of homogeneity at a molecular level among contemporary isolates of S. enterica serotype Typhimurium DT104 from animal, human, and food sources in this region.

Animals↗
PubMed2006

Safety assessment of the oral cavity probiotic Streptococcus salivarius K12.

Streptococcus salivarius is a prominent member of the oral microbiota and has excellent potential for use as a probiotic targeting the oral cavity. In this report we document safety data relating to S. salivarius K12, including assessment of its antibiogram, metabolic profiles, and virulence determinants, and we examine the microbial composition of saliva following the dosing of subjects with K12.

Anti-Bacterial Agents↗
PubMed1990

Candida albicans strain delineation.

Candida albicans is a major opportunistic pathogen causing a wide spectrum of disease in human beings. Methods for strain delineation of this species to assess or predict virulence or to conduct epidemiologic or pathogenetic investigations have been developed. Although factors associated with virulence have been identified, there is no rapid system to quantitate them in a clinical laboratory. Therefore, many typing methods are based on variable phenotypic characteristics within this species including morphotyping, serotyping, antibiogram, resistogram typing, biotyping, biotyping based on commercial carbon assimilation patterns, enzyme profiles, sensitivity to yeast killer toxins, and typing based on protein variability. Phenotypically defined strains generally do not correlate with the pathogenic potential of a strain with the exception of morphotyping. However, these methods can be useful in epidemiologic investigations; for example, they have revealed that most individuals harbor one strain and that infections are frequently due to an endogenous strain. Problems with these methods usually relate to their discriminatory power. When this is maximized, reproducibility (especially between laboratories) suffers. Recently, methods based on differences in DNA structure (genotyping) for strain delineation have been developed, including electrophoretic karyotyping and restriction enzyme fragment length polymorphisms. The development of a computer-assisted data bank and analysis for these genotypic strain delineators will open investigations into the pathogenesis of this infection and permit epidemiologic studies previously not possible with this important human pathogen.

Bacterial Typing Techniques↗
PubMed1991

Susceptibility testing of anaerobic bacteria: myth, magic, or method?

The demand for susceptibility testing of anaerobes has increased, yet consensus as to procedure and interpretation in this area has not been achieved. While routine testing of anaerobic isolates is not needed, certain isolates in specific clinical settings should be tested. Also, laboratories may monitor their local antibiograms by doing periodic surveillance batch testing. The National Committee for Clinical Laboratory Standards has published a protocol of methods approved for susceptibility testing of anaerobic bacteria. Both agar and broth microdilution are included; however, the broth disk elution method is no longer approved by the National Committee for Clinical Laboratory Standards because of method-related interpretive errors. A number of newer methods are undergoing evaluation and seem promising. Clinicians and microbiologists reviewing susceptibility reports should be aware of sources of variability in the test results. Variables in susceptibility testing of anaerobes include the media and methods used, organisms chosen for testing, breakpoints chosen for interpretation, antibiotic, and determination of endpoint. Clustering of MICs around the breakpoint may lead to significant variability in test results. Adherence of testing laboratories to approved methods and careful descriptions of the method and the breakpoints used for interpretation would facilitate interlaboratory comparisons and allow problems of emerging resistance to be noted. A variety of resistance mechanisms occurs in anaerobic bacteria, including the production of beta-lactamase and other drug-inactivating enzymes, alteration of target proteins, and inability of the drug to penetrate the bacterial wall. Antimicrobial resistance patterns in the United States and abroad are described.

Animals↗
PubMed1995

New and emerging yeast pathogens.

The most common yeast species that act as agents of human disease are Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, and Cryptococcus neoformans. The incidence of infections by other yeasts has increased during the past decade. The most evident emerging pathogens are Malassezia furfur, Trichosporon beigelii, Rhodotorula species, Hansenula anomala, Candida lusitaniae, and Candida krusei. Organisms once considered environmental contaminants or only industrially important, such as Candida utilis and Candida lipolytica, have now been implicated as agents of fungemia, onychomycosis, and systemic disease. The unusual yeasts primarily infect immunocompromised patients, newborns, and the elderly. The role of central venous catheter removal and antifungal therapy in patient management is controversial. The antibiograms of the unusual yeasts range from resistant to the most recent azoles and amphotericin B to highly susceptible to all antifungal agents. Current routine methods for yeast identification may be insufficient to identify the unusual yeasts within 2 days after isolation. The recognition of unusual yeasts as agents of sometimes life-threatening infection and their unpredictable antifungal susceptibilities increase the burden on the clinical mycology laboratory to pursue complete species identification and MIC determinations. Given the current and evolving medical practices for management of seriously ill patients, further evaluations of the clinically important data about these yeasts are needed.

Carrier State↗
PubMed1995

beta-Lactamases in laboratory and clinical resistance.

beta-Lactamases are the commonest single cause of bacterial resistance to beta-lactam antibiotics. Numerous chromosomal and plasmid-mediated types are known and may be classified by their sequences or phenotypic properties. The ability of a beta-lactamase to cause resistance varies with its activity, quantity, and cellular location and, for gram-negative organisms, the permeability of the producer strain. beta-Lactamases sometimes cause obvious resistance to substrate drugs in routine tests; often, however, these enzymes reduce susceptibility without causing resistance at current, pharmacologically chosen breakpoints. This review considers the ability of the prevalent beta-lactamases to cause resistance to widely used beta-lactams, whether resistance is accurately reflected in routine tests, and the extent to which the antibiogram for an organism can be used to predict the type of beta-lactamase that it produces.

Enterobacteriaceae↗
PubMed1980

Comparison of virulence markers of peritoneal and fallopian tube isolates with endocervical Neisseria gonorrhoeae isolates from women with acute salpingitis.

Neisseria gonorrhoeae strains which cause acute salpingitis are presumed to ascend the genital tract from the cervix. Previous studies utilized isolates obtained from endocervical canal cultures, although it was not known if the isolates truly represented the organisms present in the fallopian tubes. In this study, we compared N. gonorrhoeae isolates from endocervical canal cultures with fallopian tube or peritoneal cul-de-sac isolates or isolates from both sites obtained at laparoscopy. Potential virulence markers were studied, including colony phenotype, auxotype, antimicrobial agent susceptibility, protein patterns on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and susceptibility to normal human serum. Six of seven cervical isolates had the same antibiograms and molecular weight for major outer membrane proteins as those of the corresponding peritoneal isolates. Auxotypes also were the same and included prototrophic, proline-requiring, and proline-and-arginine-requiring isolates. The isolates as a group appeared to be very susceptible to the bactericidal action of pooled serum from normal women. Colony phenotypes varied between sites; the fallopian tubecul-de-sac isolates were predominantly of transparent phenotype and piliated. The cervical isolates were either mixtures of equal quantities of opaque and transparent phenotypes or predominantly opaque phenotype. By these markers, patients' N. gonorrhoeae cervical isolates appeared to be the same as their isolates from fallopian tubes except for a difference or shift in colony phenotype.

Anti-Bacterial Agents↗
PubMed1988

Serial isolates of Pseudomonas aeruginosa from a cystic fibrosis patient have identical pilin sequences.

Five isolates of Pseudomonas aeruginosa (CD2, CD3, CD4, CD5, and CD10) from a patient with cystic fibrosis were examined with regard to several genotypic and phenotypic characteristics to determine whether the patient was colonized with one or several distinct strains. Isolates CD2, CD3, and CD4 were obtained from a single sputum sample, and CD5 and CD10 were obtained 1 and 2 years later, respectively. On the basis of colonial morphology, serotyping, and antibiograms, the five isolates appeared to be different strains. However, Southern blot analysis with a 1.2-kilobase DNA probe containing the P. aeruginosa PAK pilin gene indicated that all five strains were identical at that genetic locus. The pilin genes of the five isolates were cloned and sequenced at the nucleotide level and found to be identical. Southern blot analysis with a probe from a separate region of the P. aeruginosa chromosome, a 741-base-pair PstI-NruI DNA fragment adjacent to the exotoxin A gene, also revealed genetic identity among these five clinical isolates. On this basis, it was concluded that this patient was colonized with a single strain of P. aeruginosa and that the strain had remained genetically stable over a period of 2 years. The predicted pilin sequence of the CD isolates was almost identical to that of strain PA103 (97% homology) and serologically related to PAO pilin, with which it shared 80% homology. No immunological cross-reactivity was detected between the CD and PAK pilins, which shared the least homology (62%) among the four pilins considered in this study. Although all five CD isolates contained identical pilin genes, three had acquired mutations which prevented normal expression of the pilus system. CD3 was a putative regulatory mutant which was unable to produce normal amounts of pilin, and CD4 and CD10 were putative assembly mutants which produced normal amounts of pilin but were unable to assemble the pilin subunit into intact pili.

Amino Acid Sequence↗
PubMed2006

Characterization of Shigella strains in Iran by plasmid profile analysis and PCR amplification of ipa genes.

To characterize Shigella clinical strains, we studied 82 Shigella strains recovered from 719 stool samples of patients with bloody diarrhea in Shiraz, Iran, over the period from April to October 2003. Serological assay classified the Shigella isolates as follows: 61 (74.39%) Shigella sonnei isolates, 16 (19.51%) Shigella flexneri isolates, 3 (3.65%) Shigella boydii isolates, and 2 (2.43%) Shigella dysenteriae isolates. In an antibiogram test, all Shigella strains were susceptible to ceftazidime, ciprofloxacin, and ceftriaxone. They showed high degrees of sensitivity to nalidixic acid, gentamicin, cephalothin, and amikacin. Approximately 90.24% of the Shigella isolates were resistant to co-trimoxazole. The plasmid profile patterns of all strains were determined by a modified alkaline lysis method. The average number of plasmid bands for each strain was 9.5. By plasmid profile analysis we identified 56 genotypes among all isolates and 42, 14, 3, and 2 genotypes among the S. sonnei, S. flexneri, S. boydii, and S. dysenteriae strains, respectively. PCR assays showed that all isolates were positive for two virulence genes, ipaBCD and ipaH. In conclusion, these data mandate local monitoring of drug resistance and its consideration in the empirical therapy of Shigella infections. These results also demonstrate that plasmid profile analysis is more reliable than antibiotic susceptibility pattern analysis for the identification of Shigella epidemic strains isolated in Iran.

Adolescent↗
PubMed2006

Spread of cholera with newer clones of Vibrio cholerae O1 El Tor, serotype inaba, in India.

During 2004 and 2005, cholera was recorded in 15 states of India, with 7 outbreaks. The newly emerged Vibrio cholerae O1 Inaba had a different antibiogram and ribotype, different pulsotypes, and different mutations in the wbeT gene. Due to the absence of serogroup O139, the Inaba serotype may have acquired the potential to affect the population at large.

Anti-Bacterial Agents↗