Multidrug resistant staphylococci isolated from pigs with exudative epidermitis in North eastern Region of India

Exudative epidermatitis or greasy pig disease (GPD) is a contagious disease of pig and endemic worldwide caused by toxigenic strains under genus Staphylococcus. The present study reported an outbreak of GPD in Champhai district of Mizoram adjoining to the southern border of Myanmar. A total of 60 samples were collected from 22 clinically affected animals and processed for isolation and identification of Staphylococcus spp. All the isolates were subjected to antimicrobial sensitivity assay, biofilm production assay and detection of virulence genes, biofilm genes and mec genes followed by cloning and sequencing for phylogenetic analysis. A total of 44 staphylococci belonged to four species (S. sciuri, S. aureus,S. lentus, and S. hyicus) were isolated. Majority of the isolates were multidrug resistant with maximum resistance against ampicillin, penicillin including vancomycin. None of the S. hyicus isolates was methicillin resistant (MRSH) but 66·67% isolates were MRSA. By PCR, mecA gene was detected in S. aureus (n = 2), S. sciuri (n = 4) and S. lentus (n = 3). Biofilm associated gene icaD was detected in S. aureus (n = 3), S. sciuri (n = 5), S. hyicus (n = 4) and S. lentus (n = 6). The exfoliative toxin genes (ehxB, shetA and tsst1) were detected in S. hyicus (n = 3) and S. aureus (n = 1) isolates. All the isolates were closely related with the isolates from pigs of China, Germany, Japan and USA. The pathogens might be transmitted through illegal migration of pigs from Myanmar to India.     

Microbial communities in low permeability,high pH uranium mine tailings: characterization and potential effects

Aims

To describe the diversity and metabolic potential of microbial communities in uranium mine tailings characterized by high pH, high metal concentration and low permeability.

Methods and Results

To assess microbial diversity and their potential to influence the geochemistry of uranium mine tailings using aerobic and anaerobic culture‐based methods, in conjunction with next generation sequencing and clone library sequencing targeting two universal bacterial markers (the 16S rRNA and cpn60 genes). Growth assays revealed that 69% of the 59 distinct culturable isolates evaluated were multiple‐metal resistant, with 15% exhibiting dual‐metal hypertolerance. There was a moderately positive correlation coefficient (R = 0·43, P < 0·05) between multiple‐metal resistance of the isolates and their enzyme expression profile. Of the isolates tested, 17 reduced amorphous iron, 22 reduced molybdate and seven oxidized arsenite. Based on next generation sequencing, tailings depth was shown to influence bacterial community composition, with the difference in the microbial diversity of the upper (0–20 m) and middle (20–40 m) tailings zones being highly significant (P < 0·01) from the lower zone (40–60 m) and the difference in diversity of the upper and middle tailings zone being significant (P < 0·05). Phylotypes closely related to well‐known sulfate‐reducing and iron‐reducing bacteria were identified with low abundance, yet relatively high diversity.

Conclusions

The presence of a population of metabolically‐diverse, metal‐resistant micro‐organisms within the tailings environment, along with their demonstrated capacity for transforming metal elements, suggests that these organisms have the potential to influence the long‐term geochemistry of the tailings.

Significance and Impact of the study

This study is the first investigation of the diversity and functional potential of micro‐organisms present in low permeability, high pH uranium mine tailings.     

Actinomycetes from solitary wasp mud nest and swallow bird mud nest: isolation and screening for their antibacterial activity

The aim of this study was to isolate and screen actinomycetes from solitary wasp and swallow bird mud nests for antimicrobial activity. The actinomycetes were isolated from soil of nests of solitary wasp and swallow bird, and identified on the basis of morphological characteristics and molecular biological methods. A total of 109 actinomycetal isolates were obtained from 12 soil samples (6 from each habitat) using two media. The highest number of actinomycetes were recovered on Humic acid vitamin agar media (65.13%, n = 71) as compared to actinomycetes isolation agar media (34.86%, n = 38). The antimicrobial activity of actinomycetes isolates was determined using the agar plug method. Among 109 isolates, 51 isolates (46.78%) showed antibacterial activity by agar plug assay. The morphological and molecular characteristics confirmed that the most of active isolates in both sample belonged to the genus Streptomyces, the other potential genera like Streptosporangium, Actinomadura, Saccharopolyspora, Thermoactinomycetes and Nocardia were also recovered, but in a low frequency. The isolates designated as 8(1)*, BN-6, MN 2(6), MN 2(7) and MN 9(V) showed most promising activity against various drug resistant bacterial pathogens. It seems that the promising isolates from these unusual/unexplored habitats may prove to be an important step in development of drug for treating multi-drug resistant bacterial pathogens.     

Wastewater Irrigation Increases the Abundance of Potentially Harmful Gammaproteobacteria in Soils in Mezquital Valley,Mexico

Wastewater contains large amounts of pharmaceuticals, pathogens, and antimicrobial resistance determinants. Only a little is known about the dissemination of resistance determinants and changes in soil microbial communities affected by wastewater irrigation. Community DNAs from Mezquital Valley soils under irrigation with untreated wastewater for 0 to 100 years were analyzed by quantitative real-time PCR for the presence of sul genes, encoding resistance to sulfonamides. Amplicon sequencing of bacterial 16S rRNA genes from community DNAs from soils irrigated for 0, 8, 10, 85, and 100 years was performed and revealed a 14% increase of the relative abundance of Proteobacteria in rainy season soils and a 26.7% increase in dry season soils for soils irrigated for 100 years with wastewater. In particular, Gammaproteobacteria, including potential pathogens, such as Pseudomonas, Stenotrophomonas, and Acinetobacter spp., were found in wastewater-irrigated fields. 16S rRNA gene sequencing of 96 isolates from soils irrigated with wastewater for 100 years (48 from dry and 48 from rainy season soils) revealed that 46% were affiliated with the Gammaproteobacteria (mainly potentially pathogenic Stenotrophomonas strains) and 50% with the Bacilli, whereas all 96 isolates from rain-fed soils (48 from dry and 48 from rainy season soils) were affiliated with the Bacilli. Up to six types of antibiotic resistance were found in isolates from wastewater-irrigated soils; sulfamethoxazole resistance was the most abundant (33.3% of the isolates), followed by oxacillin resistance (21.9% of the isolates). In summary, we detected an increase of potentially harmful bacteria and a larger incidence of resistance determinants in wastewater-irrigated soils, which might result in health risks for farm workers and consumers of wastewater-irrigated crops.     

Diagnostic detection of intended bacteria associated with respiratory tract infections among Kelantanese Malaysian Hajj pilgrims by a ready-to-use,thermostable multiplex PCR assay

Bacterial respiratory tract infections (RTIs) are prone to be associated with serious health problems during the annual Hajj pilgrimage and are a public health concern due to the potential of pathogens transmission across continents. This study aimed to perform a diagnostic screening of intended bacteria associated with RTIs among Malaysian Hajj pilgrims by using a newly developed PCR assay. Expectorated sputum specimens (n = 202) and sociodemographic characteristics of the returning Hajj pilgrims were collected upon arrival in Kelantan, Malaysia. Diagnostic screening of bacterial respiratory pathogens was performed using a thermostabilized multiplex PCR assay in parallel with the sputum culture. Of the six intended bacteria: Haemophilus influenzae, Klebsiella pneumoniae, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae, the sputum specimens were found positive for H. influenzae (n = 139), K. pneumoniae (n = 20), and S. pneumoniae (n = 19) by the multiplex PCR assay. The sensitivity, specificity, positive- and negative predictive values (PPV and NPV) of this assay were 100% (95% confidence interval (CI): 97.85% to 100.00%), 92.23% (95% CI: 85.27% to 96.59%), 95.51% (95% CI: 91.61% to 97.64%) and 100.00%, respectively. The accuracy of this assay was 97.07% (95% CI: 94.31% to 98.73%). Overall, H. influenzae was found to be the predominant organism in the pilgrims’ sputa by both molecular and microbial culture methods. The multiplex PCR assay would enable a simple, faster and reliable means for the massive screening of intended bacteria compared to the sputum culture, especially during the Hajj pilgrimage.     

A Year of Infection in the Intensive Care Unit: Prospective Whole Genome Sequencing of Bacterial Clinical Isolates Reveals Cryptic Transmissions and Novel Microbiota

Bacterial whole genome sequencing holds promise as a disruptive technology in clinical microbiology, but it has not yet been applied systematically or comprehensively within a clinical context. Here, over the course of one year, we performed prospective collection and whole genome sequencing of nearly all bacterial isolates obtained from a tertiary care hospital’s intensive care units (ICUs). This unbiased collection of 1,229 bacterial genomes from 391 patients enables detailed exploration of several features of clinical pathogens. A sizable fraction of isolates identified as clinically relevant corresponded to previously undescribed species: 12% of isolates assigned a species-level classification by conventional methods actually qualified as distinct, novel genomospecies on the basis of genomic similarity. Pan-genome analysis of the most frequently encountered pathogens in the collection revealed substantial variation in pan-genome size (1,420 to 20,432 genes) and the rate of gene discovery (1 to 152 genes per isolate sequenced). Surprisingly, although potential nosocomial transmission of actively surveilled pathogens was rare, 8.7% of isolates belonged to genomically related clonal lineages that were present among multiple patients, usually with overlapping hospital admissions, and were associated with clinically significant infection in 62% of patients from which they were recovered. Multi-patient clonal lineages were particularly evident in the neonatal care unit, where seven separate Staphylococcus epidermidis clonal lineages were identified, including one lineage associated with bacteremia in 5/9 neonates. Our study highlights key differences in the information made available by conventional microbiological practices versus whole genome sequencing, and motivates the further integration of microbial genome sequencing into routine clinical care.     

Amplicon-based profiling of bacteria in raw and secondary treated wastewater from treatment plants across Australia

In this study, we investigated the use of Illumina high-throughput sequencing of 16S ribosomal RNA (rRNA) amplicons to explore microbial diversity and community structure in raw and secondary treated wastewater (WW) samples from four municipal wastewater treatment plants (WWTPs A–D) across Australia. Sequence reads were analyzed to determine the abundance and diversity of bacterial communities in raw and secondary treated WW samples across the four WWTPs. In addition, sequence reads were also characterized to phenotypic features and to estimate the abundance of potential pathogenic bacterial genera and antibiotic-resistant genes in total bacterial communities. The mean coverage, Shannon diversity index, observed richness (S _obs), and abundance-based coverage estimate (ACE) of richness for raw and secondary treated WW samples did not differ significantly (P > 0.05) among the four WWTPs examined. Generally, raw and secondary treated WW samples were dominated by members of the genera Pseudomonas, Arcobacter, and Bacteroides. Evaluation of source contributions to secondary treated WW, done using SourceTracker, revealed that 8.80–61.4% of the bacterial communities in secondary treated WW samples were attributed to raw WW. Twenty-five bacterial genera were classified as containing potential bacterial pathogens. The abundance of potentially pathogenic genera in raw WW samples was higher than that found in secondary treated WW samples. Among the pathogenic genera identified, Pseudomonas and Arcobacter had the greatest percentage of the sequence reads. The abundances of antibiotic resistance genes were generally low (<0.5%), except for genes encoding ABC transporters, which accounted for approximately 3% of inferred genes. These findings provided a comprehensive profile of bacterial communities, including potential bacterial pathogens and antibiotic-resistant genes, in raw and secondary treated WW samples from four WWTPs across Australia and demonstrated that Illumina high-throughput sequencing can be an alternative approach for monitoring WW quality in order to protect environmental and human health.

     

Targeting Acyl Homoserine Lactones (AHLs) by the quorum quenching bacterial strains to control biofilm formation in Pseudomonas aeruginosa

Navigating novel biological strategies to mitigate bacterial biofilms have great worth to combat bacterial infections. Bacterial infections caused by the biofilm forming bacteria are 1000 times more resistant to antibiotics than the planktonic bacteria. Among the known bacterial infections, more than 70% involve biofilms which severely complicates treatment options. Biofilm formation is mainly regulated by the Quorum sensing (QS) mechanism. Interference with the QS system by the quorum quenching (QQ) enzyme is a potent strategy to mitigate biofilm. In this study, bacterial strains with QQ activity were identified and their anti-biofilm potential was investigated against the Multidrug Resistant (MDR) Pseudomonas aeruginosa. A Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136-based bioassays were used to confirm the degradation of different Acyl Homoserine Lactones (AHLs) by QQ isolates. The 16S rRNA gene sequencing of the isolated strains identified them as Bacillus cereus strain QSP03, B. subtilis strain QSP10, Pseudomonas putida strain QQ3 and P. aeruginosa strain QSP01. Biofilm mitigation potential of QQ isolates was tested against MDR P. aeruginosa and the results suggested that 50% biofilm reduction was observed by QQ3 and QSP01 strains, and around 60% reduction by QSP10 and QSP03 bacterial isolates. The presence of AHL degrading enzymes, lactonases and acylases, was confirmed by PCR based screening and sequencing of the already annotated genes aiiA, pvdQ and quiP. Altogether, these results exhibit that QQ bacterial strains or their products could be useful to control biofilm formation in P.aeruginosa.     

Detection of hemolytic bacteria from <Emphasis Type="Italic">Palythoa caribaeorum</Emphasis> (Cnidaria,Zoantharia) using a novel palytoxin-screening assay

Palytoxin (PTX), one of the most potent and chemically complex marine toxins, is predominantly found in zoanthid corals and sporadically in dinoflagellates. Its biosynthesis and metabolic pathways are largely unknown. However, the widespread occurrence of the toxin in phylogenetically distinct marine organisms is consistent with its production by microorganisms and subsequent accumulation in the food chain. To investigate a possible microbial origin, bacteria from two zoanthid corals (Palythoa caribaeorum, Zoanthus pulchellus) and one sponge (Neofibularia nolitangere) were isolated. More than 250 bacteria were screened for hemolysis using a newly developed PTX-screening assay of which 7% showed PTX-like hemolytic activity. 16S rRNA gene sequencing revealed that these bacterial isolates belonged to strains of Bacillus cereus group (n = 11) as well as the genera Brevibacterium (n = 4) and Acinetobacter (n = 2). The results indicate the presence of Na⁺/K⁺-ATPase toxins and possibly PTX in hemolytic bacteria from P. caribaeorum.     

Occurrence of the genes encoding carbapenemases,ESBLs and class 1 integron-integrase among fermenting and non-fermenting bacteria from retail goat meat

The present study was planned to detect the genes encoding carbapenemases, ESBLs and class 1 integron-integrase among bacteria obtained from retail goat meat. Fermenting and non-fermenting bacterial isolates (n = 57), recovered from 61 goat meat samples, were identified by 16S rRNA gene sequencing. Antimicrobial susceptibility of isolates was tested by the broth dilution method using ceftazidime, cefotaxime, meropenem and imipenem. Plasmids were isolated and tested for their physical characters. Plasmids were subjected to screening of carbapenemase, ESBL and intI1 gene. Conjugation assay was performed using bla_NDM-positive isolates as the donor, and Escherichia coli HB101 as the recipient. Isolates showed the high rates of resistance to ceftazidime (77·2%), cefotaxime (70·2%), meropenem (22·8%) and imipenem (17·5%). They showed variability in number and size (~1 to >20 kb) of plasmids. Among all, 1, 4, 13 and 31 isolates showed the bla_KPC, bla_NDM, bla_SHV and bla_TEM genes, respectively. The bla_KPC-2 gene was observed in one E. coli isolate. The bla_NDM-1 gene was detected in Stenotrophomonas maltophilia (n = 2), Acinetobacter baumannii (n = 1) and Ochrobactrum anthropi (n = 1) isolates. These isolates co-harboured the bla_TEM and bla_SHV genes. The intI1 gene was detected in 22 (38·6%) isolates, and 16 of these isolates showed the carbapenemase and/or ESBL genes. The conjugative movement of bla_NDM gene could not be proved after three repetitive mating experiments. The presence of genes encoding carbapenemases and ESBLs in bacteria from goat meat poses public health risks.     

Screening and selection of stress resistant Lactobacillus spp. isolated from the marine oyster (Crassostrea gigas)

We attempted to isolate Lactobacillus spp. from the marine oyster (Crassostrea gigas) and select stress resistant strains for development of a future marine aquaculture feed adjuvant. A total of 83 lactobacilli strains were isolated from oyster. They were all Gram-positive, rod-shaped and catalase-negative. By performing a stress resistance assay, we selected eighteen isolates. Based on 16S rRNA gene sequencing, Lactobacillus paracasei was the most prevalent species among the selected isolates. The in vitro antagonistic effect of the selected strains against fish pathogens was assayed by measurement of inhibition diameters. Except for MH44, MH51, MH53 and MH62, most of the isolates showed inhibition of Vibrio alginolyticus and Vibrio proteolyticus (diameters over 15 mm). Lactobacillus rhamnosus MH22 was selected as the most stress resistant strain showing the MICs of 1.8 M NaCl, 14% ethanol and 0.014% hydrogen peroxide. L. rhamnosus MH22 isolated from oyster has a potential to be applied as a microbial feed adjuvant for marine aquaculture.     

Molecular characterization of airborne fungi in caves of the Mogao Grottoes, Dunhuang, China

In this study, we analyzed air samples collected from several sites within the Mogao Grottoes, Dunhuang, China. The samples were collected each month from September 2008 to August 2009 from an open cave (OC), a semi-open cave (SC), a closed cave (CC), and the entrance (EN) of the Mogao Grottoes. Sampling was carried out using a six-stage Andersen FA-I sampler; then samples were cultured and fungal isolates were identified by partial sequencing of their internal transcribed spacer (ITS) region. Eleven different fungal genera were found, and the most prevalent was Cladosporium, followed by Fusarium, Penicillium, Alternaria, and Aspergillus. The fungal community composition varied among the four sites. Fungal community structure was significantly related to site (r = −0.293, p = 0.039) and to time of year (r = −0.523, p = 0.000). The concentrations and abundance of airborne fungi varied greatly throughout the year at the four sampling sites. Meteorological parameters (e.g., temperature, relative humidity) and the number of visitors also influenced both abundance and community structure of airborne fungi in the Mogao Grottoes.     

Turbinaria ornata and its associated epiphytic Bacillus sp. A promising molecule supplier to discover new natural product approaches

Marine ecosystems are highly dependent on macroalgea in providing food and shelter for aquatic organisms, interacting with many bacteria and mostly producing secondary metabolites of potent therapeutic antibacterial property. Screening of marine microbial secondary metabolites of valuable biotechnological and therapeutical applications are now extensively studied. In this study, Bacillus spp. identified by DNA sequencing and found associated with Turbinaria ornata, was screened and characterized for its cell free supernatant (CFS) possible antimicrobial and antibiofilm applications. Among the 7 microbial isolates tested, CFS greatly affected Bacillus subitilis (12 mm) and inhibited equally the yeast isolates Candida albicans, Candida tropicalis and Candida glabrata (10 mm) and had no or negligible effect on S.aureus, E.coli, P. aeruginosa. As for the CFS antibiofilm activity, no difference was revealed from the positive control. Algal crude extracts (methanol, acetone and aqueous), on the other hand, were similarly tested for their antimicrobial activity against the seven microbial isolates, where highest activity was observed with the aqueous crude extract against Staphylococcus aureus(10 mm) and Pseudomonas aeruginosa (9 mm) compared to the negligible effects of methanol and acetone crude extracts. Chemical analysis was performed to reveal the major constituents of both crude algal extracts and Bacillus spp. CFS. FTIR spectrum of the bacterial CFS indicated the presence of bacteriocin as the major lipopeptide responsible for its biological activity. Whereas, methanol and water crude algal extract GC–MS spectra revealed different chemical groups of various combined therapeutical activity mainly Naphthalene, amino ethane-sulfonic acid, pyrlene, Biotin and mercury chloromethyl correspondingly. Thus, the present study, demonstrated the moderate activity of both crude algal extract and the bacterial CFS, however, further investigations are needed for a better biological activity.     

Sugar Beet-Associated Bacterial and Fungal Communities Show a High Indigenous Antagonistic Potential Against Plant Pathogens

The aim of this study was to analyze microbial communities in/on sugar beet with special focus on antagonists toward plant pathogens. For this purpose, the composition of microorganisms isolated from the rhizosphere, phyllosphere, endorhiza, and endosphere of field-grown sugar beet plants was analyzed by a multiphasic approach at three different plant development stages at six locations in Europe. The analysis of microbial communities by Single Strand Conformation Polymorphism (SSCP) of 16S/18S rRNA clearly revealed the existence of discrete microenvironment- and site-specific patterns. A total of 1952 bacterial and 1344 fungal isolates screened by dual testing for antagonism toward the pathogens Aphanomyces cochlioides, Phoma betae, Pythium ultimum, and Rhizoctonia solani resulted in 885 bacterial (=45%) and 437 fungal (=33%) antagonists. In general, the indigenous antagonistic potential was very high and influenced by (a) the location, (b) the plant developmental stage, and (3) the microenvironment. Furthermore, we showed for the first time that the antagonistic potential was highly specific for each target pathogen. The majority of antagonistic microorganisms suppressed only one pathogen (bacteria: 664 = 75%; fungi: 256 = 59%), whereas the minority showed a broad host range (bacteria: 4 = 0.5%; fungi: 7 = 1.6%). The bacterial communities harbored the highest antagonistic potential against P. ultimum, whereas the fungal communities contained more antagonists against A. cochlioides and R. solani. In contrast to their high proportion, only a low diversity of antagonists at genotypic and species level was found. Novel antagonistic species, e.g., Subtercola pratensis or Microbacterium testaceum were found in the internal part of the sugar beet body.     

Molecular characterization of Plasmodium vivax clinical isolates in Pakistan and Iran using pvmsp-1, pvmsp-3α and pvcsp genes as molecular markers

In this study, the diversity of Plasmodium vivax populations circulating in Pakistan and Iran has been investigated by using circumsporozoite protein (csp) and merozoite surface proteins 1 and 3α (msp-1 and msp-3α) genes as genetic markers. Infected P. vivax blood samples were collected from Pakistan (n = 187) and Iran (n = 150) during April to October 2008, and were analyzed using nested-PCR/RFLP and sequencing methods. Genotyping pvmsp-1 (variable block 5) revealed the presence of type 1, type 2 and recombinant type 3 allelic variants, with type 1 predominant, in both study areas. The sequence analysis of 33 P. vivax isolates from Pakistan and 30 from Iran identified 16 distinct alleles each, with one allele (R-8) from Iran which was not reported previously. Genotyping pvcsp gene also showed that VK210 type is predominant in both countries. Moreover, based on the size of amplified fragment of pvmsp-3α, three major types: type A (1800 bp), type B (1500 bp) and type C (1200 bp), were distinguished among the examined isolates that type A was predominant among Pakistani (72.7%) and Iranian (77.3%) parasites. PCR/RFLP products of pvmsp-3α with HhaI and AluI have detected 40 and 39 distinct variants among Pakistani and Iranian examined isolates, respectively. Based on these three studied genes, the rate of combined multiple genotypes were 30% and 24.6% for Pakistani and Iranian P. vivax isolates, respectively. These results indicate an extensive diversity in the P. vivax populations in both studies.     

Nasopharyngeal microbiome reveals the prevalence of opportunistic pathogens in SARS-CoV-2 infected individuals and their association with host types

The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is causing a severe global health emergency owing to its highly infectious nature. Although the symptoms of SARS-CoV-2 are well known but its impact on nasopharyngeal microbiome is poorly studied. The present cross-sectional study was intended to understand the perturbation in the nasopharyngeal microbiome composition within the infected (n = 63) and non-infected (n = 26) individuals using 16S rRNA gene based targeted amplicon sequencing and their association with host types and the prevalence of opportunistic pathogens at the stage of infection. The results confirmed that number of OTUs were significantly (p < 0.05) decreased in the SARS-CoV-2 infected individuals in comparison to non-infected individuals. Pairwise Wilcoxon test showed a significant (p < 0.05) increase in the abundance of Proteobacteria in infected individuals compared to non-infected ones and vice-versa for Fusobacteria and Bacteroidetes. Similarity percentage (SIMPER) analysis showed the increment in the abundance of opportunistic pathogens (Haemophilus, Stenotrophomonas, Acinetobacter, Moraxella, Corynebacterium 1, Gemella, Ralstonia, and Pseudomonas) involved in secondary infection. Furthermore, this study highlighted the microbial community structure of individuals within and across the families. In this study, we also performed the assesment of microbiome associated with host types (age and genders) and COVID-19 conditions (symptomatic and asymptomatic). The data suggested that the host types/conditions during the COVID-19 infection are potential factors in enrichment of specific bacterial communities in upper respiratory tract.     

Antimicrobial activity of invertebrate-pathogenic fungi in the genera Akanthomyces and Gibellula

Infectious disease caused by antibiotic resistant microorganisms is a global public health problem. There is a need to search for new bioactive compounds from new sources. In this study, we focused on invertebrate-pathogenic fungi infecting spiders. One hundred and sixty-five crude extracts from Akanthomyces (n = 45) and Gibellula (n = 10) were screened for their antimicrobial activity against nine human pathogens. Twenty-one extracts out of 165 (12.73%) from 16 (29.09%) isolates exhibited antimicrobial activity against at least one test strain. The most activity was against Staphylococcus aureus American Type Culture Collection (ATCC 25923) (8.48%) followed by Cryptococcus neoformans ATCC 90112 (3.03%), C. neoformans ATCC 90113 (2.42%), methicillin-resistant Staphylococcus aureus (MRSA) SK-1 (2.42%), Penicillium marneffei (2.42%), Microsporum gypseum (1.21%), Candida albicans ATCC 90028 (1.21%), Pseudomonas aeruginosa ATCC 27853 (0.61%) and Escherichia coli ATCC 25922 (0.61%), respectively. The ethyl acetate extract of mycelia from Gibellula pulchra EPF083 had the strongest broad spectrum antimicrobial activity with a minimum inhibitory concentration (MIC) value of 16 μg/ml against S. aureus ATCC 25923, MRSA SK-1, C. neoformans (ATCC 90112 and ATCC 90113) and P. marneffei and exhibited fungicidal activity against C. neoformans ATCC 90112 and P. marneffei with minimum fungicidal concentration (MFC) values of 16 and 32 μg/ml, respectively. These preliminary data show that invertebrate-pathogenic fungi could be a potential source of antimicrobial agents.     

Plasmodium vivax: immunological properties of tryptophan-rich antigens PvTRAg 35.2 and PvTRAg 80.6

Need for malaria vaccine necessitates the characterization of potential antigens of the Plasmodium parasite. Recently, we have identified several Plasmodium vivax tryptophan-rich antigens (PvTRAgs). Here, we describe the immunological characterization of hitherto undescribed two such antigens PvTRAg 35.2 and PvTRAg 80.6 which are respective homologue of Plasmodium falciparum merozoite associated tryptophan-rich antigen (PfMaTrA) and P. falciparum tryptophan and threonine rich antigen (PfTryThrA) involved in erythrocyte invasion. Each of the pvtrag genes is comprised of two exons where exon 2 encodes for major part of the protein. PvTRAg 35.2 and PvTRAg 80.6 showed 97.06% and 94.12% (n = 34) seropositivity rates, and 92.3% (n = 13) and 100% (n = 29) lymphoproliferative responses, respectively, among P. vivax exposed individuals. Geometric mean values of IL-12, IFN-γ, TNF-α, IL-4 and IL-10 in PBMC culture supernatants of P. vivax exposed individuals were 182.02, 60.3, 62.84, 196.01 and 177.17 pg/ml against PvTRAg 35.2 and 185.27, 58.15, 64.56, 142.01 and 157.2 pg/ml against PvTRAg 80.6 showing mixed immune response with distinct biased towards anti-inflammatory Th2 phenotype. The pvtrag 35.2 gene was highly conserved in the parasite population whereas pvtrag 80.6 showed minor variations in the N-terminal region but highly conserved in the C-terminal region containing tryptophan-rich domain.     

Evaluation of Potential Probiotics Isolated from Human Milk and Colostrum

Several studies have demonstrated a diversity of bacterial species in human milk, even in aseptically collected samples. The present study evaluated potential probiotic bacteria isolated from human milk and associated maternal variables. Milk samples were collected from 47 healthy women and cultured on selective and universal agar media under aerobic and anaerobic conditions. Bacterial isolates were counted and identified by Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight mass spectrometry and then tested for probiotic properties. Total bacteria in human milk ranged from 1.5 to 4.0 log₁₀ CFU/mL. The higher bacterial counts were found in colostrum (mean = 3.9 log₁₀ CFU/mL, 95% CI 3.14–4.22, p = 0.00001). The most abundant species was Staphylococcus epidermidis (n = 76). The potential probiotic candidates were Lactobacillus gasseri (n = 4), Bifidobacterium breve (n = 1), and Streptococcus salivarius (n = 4). Despite the small sample size, L. gasseri was isolated only in breast milk from mothers classified into a normal weight range and after a vaginally delivered partum. No potential probiotics showed antagonism against pathogens, but all of them agglutinated different pathogens. Nine bacterial isolates belonging to the species L. gasseri, B. breve, and S. salivarius were selected as potential probiotics. The present study confirms the presence in breast milk of a bacterial microbiota that could be the source of potential probiotic candidates to be used in the formula of simulated maternal milk.     

Widespread Emergence of Multidrug Resistant <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> Isolated from CSF Samples

Bacterial infections of the central nervous system, especially acute infections such as bacterial meningitis require immediate, invariably empiric antibiotic therapy due to the widespread emergence of resistance among bacterial species. Nosocomial infections by Pseudomonas aeruginosa have been described with an increasing trend towards multidrug resistance. P. aeruginosa isolates n = 53 (66%) isolated from the cerebrospinal fluid (CSF) were used for this study. Antibiotic resistance in 53 P. aeruginosa clinical isolates from 80 CSF samples were evaluated. Of these, n = 42 (80%) of the isolates showed multidrug resistance to more than eight antibiotics and n = 17 (32%) isolates were found to be imipenem resistant P. aeruginosa (IMPR-Pa). Genotypical examination by ERIC based PCR revealed minor genetic variations. Polymicrobial infections are common in the CSF samples. However, high prevalence of P. aeruginosa as an opportunistic pathogen has been developing with increased resistance to antimicrobial agents and thus becoming a significant threat.