Genetic characterization of co-trimoxazole non-susceptible Streptococcus pneumoniae isolates from Indonesia
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ABSTRACT:
SUBMITTER: Safari D
PROVIDER: S-EPMC8604174 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The soil-borne pathogen Nocardia sp. causes severe cutaneous, pulmonary, and central nervous system infections. Against them, co-trimoxazole (SXT) constitutes the mainstay of antimicrobial therapy. However, some Nocardia strains show resistance to SXT, but the underlying genetic basis is unknown. We investigated the presence of genetic resistance determinants and class 1-3 integrons in 76 SXT-resistant Nocardia strains by PCR and sequencing. By E test, these clinical strains showed SXT minimum inhibitory concentrations of ?32:608 mg/L (ratio of 1:19 for trimethoprim: sulfamethoxazole). They belonged to 12 species, being the main representatives Nocardia farcinica (32%), followed by N. flavorosea (6.5%), N. nova (11.8%), N. carnea (10.5%), N. transvalensis (10.5%), and Nocardia sp. (6.5%). The prevalence of resistance genes in the SXT-resistant strains was as follows: sul1 and sul2 93.4 and 78.9%, respectively, dfrA(S1) 14.7%, blaTEM-1 and blaZ 2.6 and 2.6%, respectively, VIM-2 1.3%, aph(3')-IIIa 40.8%, ermA, ermB, mefA, and msrD 2.6, 77.6, 14.4, and 5.2%, respectively, and tet(O), tet(M), and tet(L) 48.6, 25.0, and 3.9%, respectively. Detected amino acid changes in GyrA were not related to fluoroquinolone resistance, but probably linked to species polymorphism. Class 1 and 3 integrons were found in 93.42 and 56.57% strains, respectively. Class 2 integrons and sul3 genes were not detected. Other mechanisms, different than dfrA(S1), dfrD, dfrF, dfrG, and dfrK, could explain the strong trimethoprim resistance shown by the other 64 strains. For first time, resistance determinants commonly found in clinically important bacteria were detected in Nocardia sp. sul1, sul2, erm(B), and tet(O) were the most prevalent in the SXT-resistant strains. The similarity in their resistome could be due to a common genetic platform, in which these determinants are co-transferred.
| S-EPMC4412068 | biostudies-literature
Project description:OBJECTIVES:This study aimed to define the molecular basis of co-trimoxazole resistance in Malawian pneumococci under the dual selective pressure of widespread co-trimoxazole and sulfadoxine/pyrimethamine use. METHODS:We measured the trimethoprim and sulfamethoxazole MICs and analysed folA and folP nucleotide and translated amino acid sequences for 143 pneumococci isolated from carriage and invasive disease in Malawi (2002-08). RESULTS:Pneumococci were highly resistant to both trimethoprim and sulfamethoxazole (96%, 137/143). Sulfamethoxazole-resistant isolates showed a 3 or 6 bp insertion in the sulphonamide-binding site of folP. The trimethoprim-resistant isolates fell into three genotypic groups based on dihydrofolate reductase (encoded by folA) mutations: Ile-100-Leu (10%), the Ile-100-Leu substitution together with a residue 92 substitution (56%) and those with a novel uncharacterized resistance genotype (34%). The nucleotide sequence divergence and dN/dS of folA and folP remained stable from 2004 onwards. CONCLUSIONS:S. pneumoniae exhibit almost universal co-trimoxazole resistance in vitro and in silico that we believe is driven by extensive co-trimoxazole and sulfadoxine/pyrimethamine use. More than one-third of pneumococci employ a novel mechanism of co-trimoxazole resistance. Resistance has now reached a point of stabilizing evolution. The use of co-trimoxazole to prevent pneumococcal infection in HIV/AIDS patients in sub-Saharan Africa should be re-evaluated.
| S-EPMC3886935 | biostudies-literature
Project description:As part of an ongoing surveillance program of antibiotic-resistant Streptococcus pneumoniae in Sofia, Bulgaria, 120 penicillin-resistant strains (PRSP) (most of them recovered from children hospitalized with pneumococcal disease) were analyzed by microbiological and molecular methods. Several unique features of this collection are of particular interest. (i) Most isolates (112 of 120) were also resistant to trimethoprim-sulfamethoxazole (SXT) (97 of 120 isolates, or 80%), and over 70% (86 of 120) of the isolates were resistant to at least three antibiotics in addition to penicillin. (ii) Close to 80% of all isolates were represented by large clusters of bacteria, each with a unique serotype, antibiotype, and chromosomal macrorestriction pattern (determined by pulsed-field gel electrophoresis), as well as unique restriction fragmentation length polymorphisms of the penicillin-binding protein genes pbp1a, pbp2x, and pbp2b. (iii) A large proportion (45 of 120, or 38%) of the strains belonged to two internationally spread epidemic clones of S. pneumoniae, the first expressing capsular type 23F and the second expressing serotype 9. (iv) A unique Bulgarian cluster composed of eight serotype 19F isolates was resistant to tetracycline, SXT, cefotaxime, and extremely high levels of penicillin and erythromycin. Nevertheless, this clone did not react with either the erm or the mef DNA probes, and thus the mechanism of macrolide resistance in this group of PRSP remains to be elucidated.
| S-EPMC84503 | biostudies-literature
Project description:Thirty-four ciprofloxacin-resistant (MIC > or = 2 microg/ml) and 12 ciprofloxacin-susceptible clinical isolates of Streptococcus pneumoniae were divided into four groups based upon susceptibility to norfloxacin and the effect of reserpine (20 microg/ml). The quinolone-resistance-determining regions of parC, parE, gyrA, and gyrB of all ciprofloxacin-resistant clinical isolates were sequenced, and the activities of eight other fluoroquinolones, acriflavine, ethidium bromide, chloramphenicol, and tetracycline in the presence and absence of reserpine were determined. Despite a marked effect of reserpine upon the activity of norfloxacin, there were only a few isolates for which the activity of another fluoroquinolone was enhanced by reserpine. For most isolates the MICs of acriflavine and ethidium bromide were lowered in the presence of reserpine despite the lack of effect of this efflux pump inhibitor on fluoroquinolone activity. The strains that were most resistant to the fluoroquinolones were predominantly those with mutations in three genes. Expression of the gene encoding the efflux pump PmrA was examined by Northern blotting (quantified by quantitative competitive reverse transcriptase PCR) and compared with that of S. pneumoniae R6 and R6N. Within each group there were isolates that had high-, medium-, and low-level expression of this gene; however, increased expression was not exclusively associated with those isolates with a phenotype suggestive of an efflux mutant. These data suggest that there is another reserpine-sensitive efflux pump in S. pneumoniae that extrudes ethidium bromide and acriflavine but not fluoroquinolones.
| S-EPMC127475 | biostudies-literature
Project description:The oral streptococcal group (mitis phylogenetic group) currently consists of nine recognized species, although the group has been traditionally difficult to classify, with frequent changes in nomenclature over the years. The pneumococcus (Streptococcus pneumoniae), an important human pathogen, is traditionally distinguished from the most closely related oral streptococcal species Streptococcus mitis and Streptococcus oralis on the basis of three differentiating characteristics: optochin susceptibility, bile solubility, and agglutination with antipneumococcal polysaccharide capsule antibodies. However, there are many reports in the literature of pneumococci lacking one or more of these defining characteristics. Sometimes called "atypical" pneumococci, these isolates can be the source of considerable confusion in the clinical laboratory. Little is known to date about the genetic relationships of such organisms with classical S. pneumoniae isolates. Here we describe these relationships based on sequence analysis of housekeeping genes in comparison with previously characterized isolates of S. pneumoniae, S. mitis, and S. oralis. While most pneumococci were found to represent a closely related group these studies identified a subgroup of atypical pneumococcal isolates (bile insoluble and/or "acapsular") distinct from, though most closely related to, the "typical" pneumococcal isolates. However, a large proportion of isolates, found to be atypical on the basis of capsule reaction alone, did group with typical pneumococci, suggesting that they have either lost capsule production or represent as-yet-unrecognized capsular types. In contrast to typical S. pneumoniae, isolates phenotypically identified as S. mitis and S. oralis, which included isolates previously characterized in taxonomic studies, were genetically diverse. While most of the S. oralis isolates did fall into a well-separated group, S. mitis isolates did not cluster into a well-separated group. During the course of these studies we also identified a number of potentially important pathogenic isolates, which were frequently associated with respiratory disease, that phenotypically and genetically are most closely related to S. mitis but which harbor genes encoding the virulence determinants pneumolysin and autolysin classically associated with S. pneumoniae.
| S-EPMC97291 | biostudies-literature
Project description:The telithromycin susceptibility of 210 erythromycin-resistant pneumococci was tested with the agar diffusion method. Twenty-six erm(B)-positive isolates showed heterogeneous resistance to telithromycin, which was manifested by the presence of colonies inside the inhibition zone. When these cells were cultured and tested, they showed stable, homogeneous, and high-level resistance to telithromycin.
| S-EPMC1472201 | biostudies-literature
Project description:Twenty-nine penicillin-susceptible serotype 6B strains isolated from patients with invasive diseases and from healthy carriers were examined by different genotyping methods. Ten groups were identified on the basis of the pulsed-field gel electrophoresis (PFGE) profiles, and two of these contained multiple isolates and were analyzed further. PFGE group 1 comprised 12 isolates, the majority of which had a multiresistant phenotype (resistance to erythromycin, clindamycin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole), corresponding to that of a clone previously described in the Mediterranean area and related to penicillin-resistant clone Spain(6B)-2. The pbp2b, pbp2x, dhf, and pspA genes of the isolates had identical restriction profiles; and the partial sequence of pspA was identical to that of clone Spain(6B)-2. In all isolates the resistance determinants erm(B) and tet(M) were inserted in a Tn1545-like element; 11 isolates carried cat as part of the integrated plasmid pC194. Multilocus sequence typing (MLST) performed with two isolates confirmed that their profiles corresponded to that of the Mediterranean clone. PFGE group 2 comprised nine strains, of which the majority showed no antibiotic resistance. Their pspA profiles were different, and the partial sequences obtained for two representative isolates indicated the presence of PspA proteins of different clades. The MLST profile of one strain was identical to that of a serotype 6B strain from the United Kingdom, while two other isolates were novel one-allele variants. This clone appears to be related (five of seven identical alleles) to two other internationally disseminated clones, Hungary(19A)-6 and Poland(23F)-16, both of which are penicillin resistant. The presence of antibiotic-susceptible isolates of this clone suggests that traits other than antibiotic resistance can make a clone successful.
| S-EPMC165367 | biostudies-literature
Project description:Streptococcus pneumoniae is a human pathogenic bacterium able to cause invasive pneumococcal diseases. Some studies have reported medicinal plants having antibacterial activity against pathogenic bacteria. However, antibacterial studies of medicinal plants against S. pneumoniae remains limited. Therefore, this study aims to describe the antibacterial activity of medicinal plants in Indonesia against S. pneumoniae. Medicinal plants were extracted by maceration with n-hexane, ethanol, ethyl acetate and water. Antibacterial activity was defined by inhibition zone and minimum inhibitory concentration (MIC). Bactericidal activity was measured by culture and time-killing measurement. Methods used to describe the mechanism of action of the strongest extract were done by absorbance at 595 nm, broth culture combined with 1% crystal violet, qRT-PCR targeting lytA, peZT and peZA, and transmission electron microscope to measure bacterial lysis, antibiofilm, LytA and peZAT gene expression, and ultrastructure changes respectively. Among 13 medicinal plants, L. inermis Linn. ethyl acetate extract showed the strongest antibacterial activity against S. pneumoniae with an MIC value of 0,16 mg/ml. Bactericidal activity was observed at 0,16 mg/ml for 1 hour incubation. Lawsonia inermis extract showed some mechanism of actions including bacterial lysis, antibiofilm, and ultrastructure changes such as cell wall disruption, decreasing cell membrane integrity and morphological disorder. Increasing of lytA and decreasing of peZA and peZT expression were also observed after incubation with the extract. In addition, liquid chromatography mass spectrophotometer showed phenolic compounds as the commonest compound in L. inermis ethyl acetate extract. This study describes the strong antibacterial activity of L. inermis with various mechanism of action including ultrastructure changes.
| S-EPMC9469987 | biostudies-literature
Project description:The vic two-component signal transduction system of Streptococcus pneumoniae is essential for growth. The vic operon comprises three genes encoding the following: VicR, a response regulator of the OmpR family; VicK, its cognate histidine kinase; and VicX, a putative protein sharing 55% identity to the predicted product (YycJ) of an open reading frame in the Bacillus subtilis genome. We show that not only is vic essential for viability but it also influences virulence and competence. A putative transcriptional start site for the vic operon was mapped 16 bp upstream of the ATG codon of vicR. Only one transcript of 2.9 kb, encoding all three genes, was detected by Northern blot analysis. VicK, an atypical PAS domain-containing histidine kinase, can be autophosphorylated in vitro, and VicR functions in vitro as a phospho-acceptor protein. (PAS is an acronym formed from the names of the proteins in which the domains were first recognized: the Drosophila period clock protein [PER], vertebrate aryl hydrocarbon receptor nuclear translocator [ARNT], and Drosophila single-minded protein [SIM].) PAS domains are commonly involved in sensing intracellular signals such as redox potential, which suggests that the signal for vic might also originate in the cytoplasm. Growth rate, competence, and virulence were monitored in strains with mutations in the vic operon. Overexpression of the histidine kinase, VicK, resulted in decreased virulence, whereas the transformability of a null mutant decreased by 3 orders of magnitude.
| S-EPMC130280 | biostudies-literature
Project description:Eight low-passage-number Streptococcus pneumoniae clinical isolates, each of a different serotype and a different multilocus sequence type, were obtained from pediatric participants in a pneumococcal vaccine trial. Comparative genomic analyses were performed with these strains and two S. pneumoniae reference strains. Individual genomic libraries were constructed for each of the eight clinical isolates, with an average insert size of approximately 1 kb. A total of 73,728 clones were picked for arraying, providing more than four times genomic coverage per strain. A subset of 4,793 clones were sequenced, for which homology searches revealed that 750 (15.6%) of the sequences were unique with respect to the TIGR4 reference genome and 263 (5.5%) clones were unrelated to any available streptococcal sequence. Hypothetical translations of the open reading frames identified within these novel sequences showed homologies to a variety of proteins, including bacterial virulence factors not previously identified in S. pneumoniae. The distribution and expression patterns of 58 of these novel sequences among the eight clinical isolates were analyzed by PCR- and reverse transcriptase PCR-based analyses, respectively. These unique sequences were nonuniformly distributed among the eight isolates, and transcription of these genes in planktonic cultures was detected in 81% (172/212) of their genic occurrences. All 58 novel sequences were transcribed in one or more of the clinical strains, suggesting that they all correspond to functional genes. Sixty-five percent (38/58) of these sequences were found in 50% or less of the clinical strains, indicating a significant degree of genomic plasticity among natural isolates.
| S-EPMC1346598 | biostudies-literature