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PubMedDate not supplied

Characteristics of CVI988/Rispens and R2/23, two prototype vaccine strains of serotype 1 Marek's disease virus.

Studies were focused on two attenuated serotype 1 Marek's disease (MD) vaccine viruses, CVI988/Rispens (passage 42) and R2/23 (passage 105). Both serotype 1 vaccine viruses provided much higher levels of protection than the prototype MD vaccine, turkey herpesvirus (HVT); the best protection was generally provided by CVI988/Rispens when compared with other vaccines. The efficacy of neither serotype 1 vaccine was improved by mixture with viruses of other serotypes (synergism). No differences between the two serotype 1 vaccines were revealed by cross-neutralization tests, thus excluding preferential in vivo neutralization by maternal antibodies as an explanation for differences in protective efficacy. Neither vaccine strain induced MD lesions or reduced growth rates in 8- or 18-week trials. Neither virus depressed humoral or cellular immune responses to antigenic challenge at 3 or 15 days after vaccination. Both virus strains exhibited altered characteristics during serial backpassage; R2/23 acquired increased oncogenic potential, and CVI988/Rispens acquired the potential for increased viremia titers, accompanied by an increased frequency of both histologic nerve lesions and gross thymic atrophy. During backpassage trials, contact spread was not observed for R2/23 and, surprisingly, seemed relatively limited for CVI988/Rispens. Studies on these two serotype 1 strains generally support the safety and efficacy of the serotype 1 class of MD vaccines.

Animals↗
PubMed1994

Epidemiology, subgroups and serotypes of rotavirus diarrhea in north Indian communities.

To know prevalence of rotavirus diarrhea subgroups and serotypes, a prospective study was conducted in rural, periurban and urban communities at Chandigarh. Weekly surveillance for diarrheal episodes was carried out in 110 families each from rural, periurban and urban localities constituting 584 children < 5 years of age from October, 1988 to February, 1991. Stool samples of 218 diarrheal episodes occurring in 115 children were subjected to rotavirus detection by ELISA. Rotavirus positive samples were further analyzed for subgroups and serotypes using specific monoclonal antibodies. Overall prevalence of rotavirus diarrhea was 4.3% (25/584). Rotavirus constituted 11.5% (25/218) of total diarrheal episodes and 22% (25/115) among the children affected with acute diarrhea. Among rural, periurban and urban communities, the overall prevalences of rotavirus diarrhea were 7.3%, 3.2% and 2.3% and episode related prevalences of 31.8%, 7.4% and 5%, respectively (chi 2 test for trend was highly significant from rural to periurban to urban localities). Forty per cent (10/25 of rotavirus positive samples were subgroup I and 60% (15/25) sub-group II. Of the 25 rotavirus strains, 40% (10) were serotype 2, 24% (n = 6) serotype 3 and 36% (n = 9) serotype 4. No definite temporal or seasonal pattern of rotavirus was observed; however, more of rotavirus diarrheal episodes (16%) occurred during winter season. Subgroups and serotypes were observed to cocirculate during the rotavirus episodes. Demonstration of serotypes in our field study imply that the vaccine to be used in our country must be cross protective to have an effective impact on rotavirus infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMedDate not supplied

[The periodic and regional characteristics of the pneumococcal serotype spectrum in children with respiratory diseases and in healthy carriers].

The aim of the work was the comparative study Streptococcus pneumoniae serotypes, isolated from healthy carriers and acute pneumonia patients in different regions of the CIS; in Moscow observations were carried out for 10 years. Specific antibodies to different S.pneumoniae capsular polysaccharide antigens were determined in blood serum samples by the method of heterogeneous enzyme immunoassay. The study revealed that S.pneumoniae serotype spectra in healthy children and in children with acute respiratory viral diseases were similar, while from pneumonia patients with complications of pleuritis caused by S.pneumoniae serotypes 1, 3, 5 and 14, were more frequently isolated. During 10 years of observations changes in the occurrence of individual serotypes were noted both in carriers and in patients. Differences in the serotype spectra of S.pneumoniae isolated in different regions were established. S.pneumoniae serotype 5 caused 70% of pleuritis cases in Tashkent, while rarely occurring in regions with the moderate climate. S.pneumoniae serotype 14, formerly causing complicated forms of pneumonia, lately became more widespread, but at the same time caused fewer cases of pneumonia with complications. High occurrence of pneumonia among children aged 1-3 years correlated with a low level of specific antibodies in the child population.

Antibodies, Bacterial↗
PubMed1993

[Prevalence of serotype 0:12 among strains of P. aeruginosa causing nosocomial infection in Spain (1980-1991)].

BACKGROUND: The aim of the present study was to characterize P. aeruginosa strains causing nosocomial infection in Spain between 1980-1990 with special emphasis on the incidence of serotype 0:12 strains. METHODS: 11,411 strains of P. aeruginosa from hospital-acquired infections were studied and epidemiologically characterized by phage-typing, serotyping and sensitivity to antimicrobial agents. The strains of the 0:12 serotype were analyzed by isoenzyme analysis. RESULTS: Although the major serotypes throughout the period studied were: 0:1, 0:6 and 0:11, the existence of serotype 0:12 strains (6%) were detected which had produced nosocomial outbreaks in surrounding countries. This serotype is homogeneous in that the epidemiologic markers and patterns of sensitivity to antibiotics and the multienzyme analysis demonstrate uniformity in the electrophoretic patterns of all the strains studied. CONCLUSIONS: The 0:12 serotype is in Spain indistinguishable by phage typing and studies of antibiotic sensitivity. It may be considered as being of clonal origin and is probably equal to that existing elsewhere in Europe.

Bacterial Proteins↗
PubMed1996

Pneumococci causing invasive disease in New Zealand, 1987-94: serogroup and serotype coverage and antibiotic resistances.

AIMS: Development of polysaccharide-conjugated pneumococcal vaccines, prompted by the ineffectiveness of the current 23-valent vaccine for young children, requires an understanding of the pneumococci causing invasive disease worldwide. We have reviewed the capsular serogroups and serotypes, and the antibiotic resistances of pneumococci identified from invasive disease in New Zealand, for the period 1987-94. METHODS: Pneumococci referred from invasive disease were serogrouped and serotyped using the Neufeld test and allocated a capsular type according to the Danish system of nomenclature. Antibiotic susceptibility testing was performed by an agar dilution method following National Committee for Clinical Laboratory Standards (NCCLS) guidelines. RESULTS: A total of 1506 pneumococci were examined of which, 584 (39.8%) were sourced from children less than 15 years and 573 (39%) were from adults 60 years or greater. The majority (88.3%) were from blood cultures. In descending order of frequency serogroups or serotypes 14, 19, 6, 9, 23, 7, 4 and 1 were common to all age-groups but serogroups 6 and 18 were significantly (p < 0.001) associated with children under 15 years and serotype 3 with adult patients. Penicillin resistance was demonstrated by 22 (1.4%) isolates, five of which showed high level resistance (MIC > or = 2 mg/L) and multidrug resistance. Fourteen percent of all isolates were resistant to at least one antibiotic and serogroups 23, 6, 18, 19 and serotype 14 accounted for 82.6% of these resistant isolates. CONCLUSIONS: The serogroups and serotypes found most frequently associated with pneumococcal disease, and antibiotic resistance, were consistent with those described overseas. Continuing surveillance of antibiotic resistances and serotypes of pneumococci causing invasive disease is recommended.

Adolescent↗
PubMed1997

[Serotypes and drug susceptibility of Pseudomonas aeruginosa isolated from clinical specimens].

Between January, 1982 and December, 1994, 236 Pseudomonas aeruginosa strains were isolated from clinical specimens at our division, and were tested for serotypes and drug-susceptibilities to 15 antibiotics. Serotype G strains were isolated at the highest frequency (32.6%), and followed by strains of serotype B (15.7%), A (11.9%), E (9.3%), I (7.2%), F and M (5.5%), non-typable (5.1%), D (3.4%), H (2.1%), C and K (0.8%). We examined the changes of isolation frequencies of different serotypes annually. Isolation frequencies of serotypes E and F showed tendency to decrease, whereas serotype I has been isolated increasingly year by year. MIC90's of the 15 antibiotics were as follows, tosufloxacin: 0.78 microgram/ml, biapenem (BIPM) and ofloxacin (OFLX): 3.13 micrograms/ml, imipenem (IPM), ceftazidime, cefozopran, cefsulodin and gentamicin: 6.25 micrograms/ml, aztreonam and amikacin: 12.5 micrograms/ml, piperacillin, cefoperazone and minocycline (MINO): 25 micrograms/ml, fosfomycin: > 100 micrograms/ml and chloramphenicol: > 200 micrograms/ml. MIC90'S of IPM, BIPM, MINO and OFLX increased 4-fold from stage I (1982-1987) through stage III (1992-1994) and the isolation frequency of drug-resistant strains increased year by year. In other words, antibiotic resistant strains appeared increasing with time. No relationship between serotypes and drug-resistance were observed.

Anti-Bacterial Agents↗
PubMed1997

[Serotypes of the human immunodeficiency virus type 1 in Madrid].

BACKGROUND: HIV-1 shows high genetic variability, mainly in the genomic region codifying the envelope proteins, which are the most immunogenic. This fact explains the high heterogeneity of antibodies against HIV-1 epitopes. Both genetic and serologic diversity has allowed to classify HIV-1 variants in several subtypes (genotypes and serotypes, respectively). The clinical and epidemiological significance of infection caused by each subtype remains to be clarified. PATIENTS AND METHODS: Serum samples from 154 HIV-seropositive individuals living in Madrid were studied. Serotyping was performed using 4 peptides belonging to the V3 env region. Epidemiological and clinical variables examined in these patients were the route of infection, the year in which HIV infection occurred, the country of birth, and the rate of disease progression (rapid versus slow). RESULTS: 148 (96.2%) samples could be serotyped, and the B class was recognized in 131 (88.5%) of them. Serotype A/C was found in 9 (6.1%). Two samples (1.3%) reacted to peptide E; however, both were also reactive against the B peptide, suggesting co-infection with B and E subtypes. Six samples were EIA-reactive for HIV-1/2 but were typed as HIV-2 alone. Infection with serotypes A/C was more frequent amongst immigrants, mainly in Africans. There was not association between any subtype and the route of infection neither a different rate of disease progression. CONCLUSION: HIV-1 serotype B is the most frequently found in HIV-seropositive individuals living in Madrid, without association with the route of infection or the clinical course of the disease. Serotypes A/C and E were found sporadically, mainly among immigrants.

Africa↗
PubMedDate not supplied

Antigenic and S-1 genomic characterization of the Delaware variant serotype of infectious bronchitis virus.

A previously unrecognized infectious bronchitis virus (IBV) serotype, referred to hereafter as the Delaware variant (DE var), was isolated from commercial broiler chickens during a severe, widespread respiratory disease epornitic in the Delmarva peninsula region of the United States in January-March 1992. The DE var serotype was found to be antigenically unrelated by virus-neutralization (VN) test to nine reference IBV serotypes from North America. Additional VN tests indicated that the DE var isolates (DE/072/92, DE/121/ 92, DE/152/92, and DE/174/92) from broilers were fully or partially neutralized by monospecific antisera prepared against themselves and against two IBV field isolates (DE/492/90 and DE/903/90) recovered from a Delmarva commercial layer flock experiencing egg production losses in 1990. Antigenic relatedness values determined by VN indicated layer isolate DE/492/90 was more closely related to the broiler DE var isolates than was layer isolate DE/903/90. Cross-challenge tests performed in specific-pathogen-free chickens also demonstrated the antigenic similarity of the broiler (DE/072/92 and DE/174/92) and the layer isolates (DE/492/90 and DE/903/90), with heterologous strain protection values ranging from 55% to 100%. Protection values of DE var isolates vs. Massachusetts 41 and Arkansas DPI were considerably lower (0-60%). The S-1 gene of the US/DE/072/92 isolate of the DE var serotype was amplified by reverse transcription polymerase chain reaction, cloned, and sequenced. The DE var S-1 gene sequence was compared with the S-1 gene sequences of IBV serotypes from North America, Europe, and Australia. A dendrogram based on this analysis supported the conclusion that the DE var serotype is highly novel among IBV. A high degree of similarity (> 88%) was observed between the S-1 genes of the DE var broiler isolates (DE/072/92 and DE/174/92) and layer isolates (DE/492/90 and DE/903/90). These data, taken with the VN and cross-challenge results, establish a genetic as well as an antigenic link between the isolates from layers and broilers and indicate the DE var serotype was responsible for both infectious bronchitis outbreaks.

Animals↗
PubMedDate not supplied

Serotype identification of avian infectious bronchitis virus by RT-PCR of the peplomer (S-1) gene.

The S-1 peplomer gene sequences of 31 strains of avian coronavirus infectious bronchitis virus (IBV) from North America, Europe, and Australia were compared to identify common and unique regions for possible diagnostic applications. S-1 sequences that were conserved among serotypes and sequences that were variable between serotypes were identified. Based on conserved S-1 gene sequences, "general" degenerate oligonucleotide primers were designed that amplified IBV genomic RNA by the reverse transcriptase polymerase chain reaction (RT-PCR) procedure regardless of serotype. Primers specific for IBV serotypes Massachusetts, Connecticut, Arkansas, JMK, Delaware (DE/072/92), and California (CA/633/85) were designed from regions of the S-1 gene exhibiting extensive sequence hypervariability. The ability to identify these six serotypes of IBV by RT-PCR was demonstrated by testing the serotype-specific primers on a panel of unknown samples that included 30 reference strains and field isolates previously characterized by virus neutralization (VN). The use of serotype-specific primers in RT-PCR provides a rapid and accurate means of identifying IBV.

Amino Acid Sequence↗
PubMed1998

Serotyping scheme for Staphylococcus aureus isolated from cows with mastitis.

OBJECTIVE: To identify the Staphylococcus aureus capsular serotypes that are not typable, using capsular serotypes 5 and 8, which are currently used to type S aureus isolated from cows with mastitis. SAMPLE POPULATION: Milk samples (n = 273) from cows with mastitis in 178 dairy herds in California, Wisconsin, Michigan, Texas, and New York that were collected by state diagnostic laboratories and S aureus-positive milk samples collected by Veterinary Health Services in the United Kingdom (15), France (22), The Netherlands (36), and Germany (21). PROCEDURE: Capsular serotyping of coded isolates was performed by use of direct cell agglutination and immunoprecipitation of cell extracts with antisera specific for capsular types 5 and 8 and a newly developed S aureus serotyping antiserum 336. RESULTS: In the United States, S aureus capsular types 5 and 8 accounted for 18 and 23% of the isolates, respectively, and type 336 accounted for 59%. Percentage of capsular serotypes in European samples were as follows: type 5 = 34%, type 8 = 34%, type 336 = 30%, and nontypable = 2%. CONCLUSIONS: Serotypes 5 and 8 accounted for only 41% of S aureus isolates from US milk samples, but accounted for 70% of isolates from European milk samples. Addition of the newly developed serotyping antiserum 336 to the typing scheme accounted for 100% of US samples and 98% of European samples and will enable development of a more comprehensive S aureus vaccine.

Agglutination Tests↗
PubMed2000

Several log increase in therapeutic transgene delivery by distinct adeno-associated viral serotype vectors.

We previously demonstrated that rAAV vectors carrying human and canine factor IX (FIX) cDNA can infect, stably persist, and secrete functional human and canine FIX following direct intramuscular injection. In an attempt to improve FIX protein secretion for eventual therapeutic use, we set out to determine if alteration of the AAV capsid would affect skeletal muscle transduction and factor IX secretion. Two reasons to pursue this question were (1) the persistence of high-titer neutralizing antibody (NAB) to AAV2 and (2) our previous study that supported a restricted tropism of muscle fiber types to AAV2 transduction. Using an identical CMV/canine factor IX (cFIX) expression cassette, we cross-packaged this genome into virions generated from each of the five AAV serotypes. In a dose-response assay, equivalent amounts of rAAV/cFIX serotypes were tested in vitro and in vivo. In tissue culture cells, FIX antigen levels secreted into the supernatant varied depending on the AAV serotype used; type 2 transduced maximally, with serotypes 3, 1, 5, and 4, respectively, expressing lower levels. However, when the same viruses were tested in vivo using immunodeficient NOD/SCID animals, we obtained surprisingly different results. While the time to onset of detectable serum levels appeared the same for all serotypes, types 1, 3, and 5 produced 100- to 1000-fold more cFIX than type 2. In fact, 12 weeks after transduction, type 1 continued to express levels of cFIX on average at 80 microg/ml followed by type 5 (6.52 microg/ml), type 3 (3.27 microg/ml), type 4 (258 ng/ml), and finally type 2 (90 ng/ml). Coagulant activity of cFIX as measured by aPTT supported the circulating levels measured by ELISA demonstrating the secreted protein was functional, and RT-PCR of injected tissue correlated with the serotype-specific transduction data. In summary, we found significant differences in cFIX expression upon introducing various rAAV serotypes into mouse muscle. These data have direct bearing on the design of AAV gene therapy clinical trials for hemophilia and should also extend to most therapeutic transgenes.

Animals↗
PubMed1996

Identification of a set of proteins (C' and C) encoded by the bicistronic P gene of the Indiana serotype of vesicular stomatitis virus and analysis of their effect on transcription by the viral RNA polymerase.

Previous work (C.F. Spiropoulou and S.T. Nichol, 1993, J. Virol. 67, 3103-3110) has demonstrated the existence in cells infected with the New Jersey serotype of vesicular stomatitis virus (VSV) of two small carboxy-coterminal proteins encoded by the P mRNA. These proteins have been named C' and C. We are interested in studying the function of these proteins in the virus life cycle. Toward this end, we have cloned the ORF encoding the potential C' protein of the Indiana serotype as a histidine-tagged fusion protein, purified the expressed protein from Escherichia coli, and used the fusion protein as an immunogen to raise antiserum in a rabbit. We have used this anti-C' protein serum to demonstrate that both of the predicted C' and C proteins are synthesized in cells infected with the Indiana serotype of VSV. In addition we have localized a portion of these proteins to nucleocapsids isolated from infected cells, suggesting that they may play a role in RNA synthesis. Reconstitution of the viral polymerase activity by expressing the L and P protein subunits with or without the C proteins failed to demonstrate any effect of the presence of these latter proteins on reconstituted transcription using purified nucleocapsids as templates. However, we have been able to show a dramatic stimulation of the polymerase activity in purified virions by the addition of purified C' protein to in vitro transcription reactions. Both the level and the fidelity of mRNA synthesis are stimulated by this protein. Evidence for the specificity of this effect comes from the fact that stimulation appears to be serotype specific; C' protein of the Indiana serotype stimulates transcription by purified Indiana serotype virions but has a minimal effect on transcription by purified virions of the New Jersey serotype. We are continuing our studies to determine the mechanism of this stimulation.

Animals↗
PubMed1996

Study of Pseudomonas aeruginosa serotype O12 isolates with a common antibiotic susceptibility pattern.

A multicentre European study of Pseudomonas aeruginosa serotype O12 isolates with a common antibiotic resistance pattern was conducted. Resistance to beta-lactams and aminoglycosides was observed in 24 of the 25 isolates, as often reported in Europe, and all 25 isolates were significantly more susceptible to fosfomycin than 189 isolates of other serotypes (72% vs. 13.2%). The mutational frequency of serotype O12 was similar to that of other serotypes and thus could not explain the susceptibility to fosfomycin. As a number of epidemiological studies using various methods, especially ribotyping with EcoRI, have shown that most strains are similar, it has been suggested that a single strain of this serotype is widespread. However, in this study ribotyping with EcoRI and PvuII distinguished seven clones among 24 ticarcillin resistant serotype O12 isolates, although one ribotype predominated (67%). Thus the hypothesis of spread of one clone across Europe cannot explain the common resistance phenotype observed in different clones of serotype O12. Resistance of beta-lactams and aminoglycosides might be explained by greater receptiveness for transposable resistance mechanisms, and susceptibility to fosfomycin by increased permeability of the outer membrane.

Anti-Bacterial Agents↗
PubMed2004

Cryptococcus neoformans mitochondrial genomes from serotype A and D strains do not influence virulence.

Cryptococcus neoformans is an encapsulated pathogenic yeast producing meningoencephalitis. Two primary strains in genetic studies, serotype A H99 and serotype D JEC21, possess dramatic differences in virulence. Since it has been shown that mitochondrial gene expression is prominent at the site of the infection and there are significant differences between mitochondrial gene structure and regulation between the serotype A and D strains, this study used AD hybrids to move serotype A and D mitochondria under different genomic influences. When the serotype D MATa strain is involved in the mating crosses, there is uniparental transmission of mitochondrial DNA, but with the serotype A MATa strain, mitochondrial DNA can be inherited from either parent and recombination in the mitochondrial genome may also occur. In virulence studies between serotype A and D strains, it was found that the primary genetic control of the virulence composite for growth in the central nervous system is encoded in the nuclear DNA and not through mitochondrial DNA.

Animals↗
PubMed1987

Comparison of the reovirus serotype 1, 2, and 3 S3 genome segments encoding the nonstructural protein sigma NS.

The sequences of the S3 genome segments of reovirus serotype 1 and 2 prototype strains are presented and these sequences are compared with the sequence of the serotype 3 S3 genome segment. The S3 genome segment encodes the nonstructural protein sigma NS which possesses affinity for ssRNA and appears to function in reovirus morphogenesis. The three S3 genome segments are closely related: all are 1198 nucleotides long and possess a single long open reading frame 366 codons long. They exhibit a serotype 1:3 relatedness pattern: there are only 13% mismatches between the S3 genome segments of serotypes 1 and 3, but 27 and 26% mismatches, respectively, between those of serotype 1 and 2 and serotype 3 and 2. The amino acid mismatches for the three sigma NS proteins are much lower (2.7, 13.9, and 13.7%, respectively), because the majority of nucleotide mismatches are in third base codon positions. The three sigma NS proteins possess a conserved secondary structure that is rich in alpha-helix content; in fact, the predicted alpha-helix content of these nonstructural proteins (about 50%) is much higher than that of the three other sigma size class proteins (about 20%), all of which are structural proteins. We also sequenced the S3 genome segment of a ts mutant of serotype 3 generated by treatment with nitrous acid and found a single nucleotide change that specifies an amino acid change that introduces a five-residue-long beta-sheet prone configuration into a long (80 amino acids) highly conserved alpha-helix in the C-terminal half of sigma NS. This change could account for this mutant's ts character. Finally, the three sigma NS proteins have diverged in only about 10% of positions, whereas the three sigma 1 proteins have diverged in about 70%. The rapid evolutionary divergence of the latter may be a result of several factors, including (i) the fact that sigma 1, but not sigma NS, is under immunologic selective pressure; (ii) the fact that the functions of sigma 1 (antigenicity and cell attachment) probably reside in two rather small domains that are not restricted spatially with respect to each other; and (iii) the fact that the functions of sigma NS, namely RNA binding and protein binding (during morphogenesis), require a highly specific overall protein configuration that may permit little variation.

Amino Acid Sequence↗
PubMed1993

A monoclonal antibody blocking ELISA to detect serotype-specific infectious bronchitis virus antibodies.

A monoclonal antibody (Mab) blocking enzyme-linked immunosorbent assay (B-ELISA) was developed and compared to a conventional indirect ELISA (I-ELISA) and a virus-neutralization (VN) test for detection of specific antibodies to avian infectious bronchitis virus (IBV) serotypes. Sera used in this study were derived from chickens experimentally inoculated with the three most prevalent IBV serotypes, Arkansas (Ark), Connecticut (Conn), and Massachusetts (Mass). Overall, there was good correlation between the results of B-ELISA and the VN test. Both detected serotype-specific antibodies in chicken sera during primary and secondary phases of the immune response. Results of both tests indicated that the antibodies produced during the primary response to IBV serotypes are strongly serotype-specific. Those produced during the secondary response react more strongly with the homologous virus, but do exhibit some level of cross-reactivity with heterologous antigens. I-ELISA detected IBV group-specific and not serotype-specific antibodies. The B-ELISA which both offers the convenience of the conventional I-ELISA and the serotype specificity of the VN test, hold excellent promise for field application in IBV diagnosis and evaluation of response to IBV vaccines.

Animals↗
PubMed1993

Blocking enzyme-linked immunosorbent assay for detection of antibodies against Actinobacillus pleuropneumoniae serotype 8.

A blocking enzyme-linked immunosorbent assay (ELISA) for detection of antibodies against Actinobacillus pleuropneumoniae serotype 8 is described. The test is based upon a competitive reaction between the serum to be tested and a polyclonal rabbit antiserum prepared against serotype 8 and absorbed with whole cells of serotypes 3 and 6. The blocking ELISA proved able to distinguish animals infected with serotype 8 from those infected with any other serotype of A. pleuropneumoniae including the antigenically closely related serotypes 3 and 6. Positive results were not observed with field sera from serotype 6 infected herds or from herds known to be free from A. pleuropneumoniae infection.

Actinobacillus Infections↗
PubMed2006

Multidrug-resistant and extended-spectrum beta-lactamase (ESBL)-producing Salmonella enterica (serotypes Typhi and Paratyphi A) from blood isolates in Nepal: surveillance of resistance and a search for newer alternatives.

OBJECTIVES: We evaluated the prevalence of multidrug resistance (MDR) and production of extended spectrum beta-lactamase (ESBL) by Salmonella enterica (serotypes Typhi and Paratyphi A) in a teaching hospital in Nepal. The MDR strains of S. enterica were also tested for susceptibility to newer antibiotics. METHODS: Blood cultures were obtained from 4105 patients with febrile illnesses. Isolates of S. enterica were serotyped and antibiotic susceptibility testing was carried out using disk diffusion (Kirby-Bauer) and E-tests. ESBL screening and phenotype confirmation were done following National Committee for Clinical Laboratory Standards (NCCLS) recommendations for Escherichia coli. RESULTS: A total of 541 isolates of S. enterica serotypes Typhi (47%) and Paratyphi A (53%) were grown. Twenty-eight isolates (5%) of S. enterica were resistant to two or more antibiotics (MDR isolates), with a greater prevalence among serotype Paratyphi A (7%). All ESBL producers (three isolates) were serotype Paratyphi A. Most of the MDR S. enterica showed reduced susceptibility to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, ofloxacin, and ciprofloxacin, and had good susceptibility to extended-spectrum cephalosporins and carbapenems. Among the fluoroquinolones, gatifloxacin demonstrated better in vitro activity compared to levofloxacin, ciprofloxacin, and ofloxacin. CONCLUSIONS: A greater prevalence of S. enterica serotype Paratyphi A with higher rates of multidrug resistance and ESBL production is concerning for natives as well as travelers in Nepal since the current typhoid vaccines do not provide protection against this serotype.

Anti-Bacterial Agents↗