Dissemination and survival of non-indigenous bacterial genomes in pristine Antarctic environments.

Continental Antarctic is perceived as a largely pristine environment, although certain localized regions (e.g., parts of the Ross Dependency Dry Valleys) are relatively heavy impacted by human activities. The procedures imposed on Antarctic field parties for the handling and disposal of both solid and liquid wastes are designed to minimise eutrofication and contamination (particularly by human enteric bacteria). However, little consideration has been given to the significance, if any, of less obvious forms of microbial contamination resulting from periodic human activities in Antarctica. The predominant commensal microorganism on human skin, Staphylococcus epidermidis, could be detected by PCR, in Dry Valley mineral soils collected from heavily impacted areas, but could not be detected in Dry Valley mineral soils collected from low impact and pristine areas. Cell viability of this non-enteric human commensal is rapidly lost in Dry Valley mineral soil. However, S. epidermidis can persist for long periods in Dry Valley mineral soil as non-viable cells and/or naked DNA

Non-specificity of Staphylococcus generic primers

Published as a "Microbiology Comment": this provides a platform for readers of Microbiology to communicate their personal observations and opinions in a more informal way than through the submission of papers.Our results allow us to conclude that there appears to be significant conservation between the tuf genes of Planococcus, Planomicrobium and Staphylococcus spp., and that although the primer set TstaG422/TStag765 has been shown to possess high specificity, its use for the definitive identification of Staphylococcus spp. must be treated with some caution

PCR-based detection of non-indigenous microorganisms in ‘pristine’ environments

PCR-based technologies are widely employed for the detection of specific microorganisms, and may be applied to the identification of non-indigenous microorganisms in ‘pristine’ environments. For ‘pristine’ environments such as those found on the Antarctic continent, the application of these methods to the assessment of environmental contamination from human activities must be treated with caution. Issues such as the possibility of non-human dispersal of organisms, stability and survival of non-indigenous organisms in vivo, the sensitivity, reproducibility and specificity of the PCR process (and particularly primer design) and the sampling regime employed must all be considered in detail. We conclude that despite these limitations, PCR and related technologies offer enormous scope for assessment of both natural and non-indigenous microbial distributions

Carbapenem resistance expressed by Gram-negative bacilli isolated from a cohort of Libyan patients

Background and objectives: Carbapenem-resistant Enterobacteriaceae (CRE) and other Gram-negative bacteria are among the most common pathogens responsible for both community and hospital acquired infection. The global spread of cephalosporinases in Enterobacteriaceae has led to the increased use of carbapenems resulting in the emergence and rapid spread of CRE. This has become an alarming public health concern, yet the condition in Libya remains unclear. The aim of this study was to obtain a better understanding of CRE strains prevalent in Libyan patients by investigating their phenotypic characteristics and antibiograms. Methods: Gram-negative bacterial species were collected from Misrata Central Hospital, Misrata Cancer Centre and Privet Pathology Laboratories. Clinical samples and swabs were obtained from hospitalised and non-hospitalised patients and from mechanical ventilation and suction machines. Patients who had received antibiotic therapy for at least three days prior to the study were excluded. The identification and characterization of the isolated species were achieved using the growth characteristics on MacConkey and blood agar, spot tests and API 20E or API 20NE biochemical testing systems. Screening for carbapenem resistance was performed using the disk diffusion method with carbapenem 10 μg and cephalosporin 30 μg disks and minimum inhibitory concentrations (MIC) determined using the Sensititre Gram-negative Xtra plate format (GNX2F). All strains demonstrating resistance or reduced susceptibility to one of the four carbapenems were subjected to carbapenememase activity detection using the RAPIDEC CARBA NP test, Modified Hodge test and carbapenem inactivation methods. Results: A total of one hundred and forty isolates representing fourteen bacterial species were isolated from 140 non-duplicated specimens. Clinical specimens included urine samples (96/140, 68.57%), sputum (15/140, 10.71%), surgical wound swabs (18/140, 12.85%), foot swabs from diabetes mellitus (DM) patients (6/140, 4.29%), ear swabs (3/140, 2.14%) and wound swabs (2/140, 1.43%). Thirty-four (24.29%) isolates demonstrated resistance to at least one of the four carbapenems with Klebsiella pneumoniae representing 73.53% (25 isolates) of all carbapenem resistant species, followed by 8.82% for Pseudomonas aeruginosa (3 isolates), 5.88% for both Proteus mirabilis (2 isolates) and Escherichia coli (2 isolates) and 2.94% for both Citrobacter koseri (1 isolate) and Rahnella aquatilis (1 isolate). The other isolates were either susceptible or cephalosporinase producers. Conclusion: This study has revealed the high rate of carbapenem resistance amongst Libyan patients and emphasizes the crucial need for accurate screening, identification and susceptibility testing to prevent further spread of nosocomial and community acquired resistance. This may be achieved through the establishment of antibiotic stewardship programmes along with firm infection control practices.National Research Foundation of South Africa; Libyan GovernmentWeb of Scienc

Bacterial diversity in three different antarctic cold desert mineral soils

A bacterial phylogenetic survey of three environmentally distinct Antarctic Dry Valley soil biotopes showed a high proportion of so-called “uncultured” phylotypes, with a relatively low diversity of identifiable phylotypes. Cyanobacterial phylotypic signals were restricted to the high-altitude sample, whereas many of the identifiable phylotypes, such as the members of the Actinobacteria, were found at all sample sites. Although the presence of Cyanobacteria and Actinobacteria is consistent with previous culture-dependent studies of microbial diversity in Antarctic Dry Valley mineral soils, many phylotypes identified by 16S rDNA analysis were of groups that have not hitherto been cultured from Antarctic soils. The general belief that such “extreme” environments harbor a relatively low species diversity was supported by the calculation of diversity indices. The detection of a substantial number of uncultured bacterial phylotypes showing low BLAST identities (<95%) suggests that Antarctic Dry Valley mineral soils harbor a pool of novel psychrotrophic taxa

Additional file 1: Figure S1. of Respiratory microbes present in the nasopharynx of children hospitalised with suspected pulmonary tuberculosis in Cape Town, South Africa

Seasonal distribution of viruses and bacteria. Figure S2. Canonical Variate Analysis (CVA) biplot depicting the spread of respiratory pathogens in the definite TB (red line) and not TB (blue line) groups only. Observations under each group are denoted by “+” signs and the median of each group by the red and blue ovals. Table S1. Target pathogens in the FTD respiratory pathogens 33 multiplex realtime PCR assay. Table S2. Summary of all paired pathogen co-occurrence counts *. Table S3. Risk factors associated with the occurrence of each microbes. (PDF 565 kb

Predominance of Central Asian strain (ST 26) in Mycobacterium tuberculosis isolates from Balochistan by spoligotyping

International audienc

Predominance of Central Asian strain (ST 26) in Mycobacterium tuberculosis isolates from Balochistan by spoligotyping

CITATION: Shafee, M. et al. 2019. Predominance of Central Asian strain (ST 26) in Mycobacterium tuberculosis isolates from Balochistan by spoligotyping. Journal of Infection in Developing Countries, 13(7):619-625, doi:10.3855/jidc.10803.The original publication is available at https://jidc.orgIntroduction: Tuberculosis is a chronic debilitating infectious disease causing a severe challenge to public health, especially in developing countries. The aim of this study was to examine genetic diversity in Mycobacterium tuberculosis strains circulating in the Balochistan region of Pakistan. Methodology: One hundred isolates collected from patients visiting the Fatima Jinnah TB Hospital in Quetta were subjected to genotype analysis by spoligotyping. Results: Three main genotypes were identified: Central Asian Strain 1 (CAS1) (n = 89), East African Indian (EAI) strain (n = 7) and Latin American Mediterranean (LAM) strain (n = 3). The CAS1 clade (ST 26) had high genetic diversity represented by seven different spoligopatterns, of which one had major predominace (n = 75). Conclusions: This is the first insight into the genotype of M. tuberculosis strains in the Balochistan region that might serve as a base line study for control of tuberculosis in the community.https://jidc.org/index.php/journal/article/view/10803Publisher's versio