We previously reported that variations in the number and type of bacteria found in public spaces are influenced by environmental factors. However, based on field survey data alone, whether the ...dynamics of bacteria in the air change as a result of a single environmental factor or multiple factors working together remains unclear. To address this, mathematical modeling may be applied. We therefore conducted a reanalysis of the previously acquired data using principal component analysis (PCA) in conjunction with a generalized linear model (Glm2) and a statistical analysis of variance (ANOVA) test employing the χ2 distribution. The data used for the analysis were reused from a previous public environmental survey conducted at 8:00-20:00 on May 2, June 1, and July 5, 2016 (regular sampling) and at 5:50-7:50 and 20:15-24:15 on July 17, 2017 (baseline sampling) in the Sapporo underground walking space, a 520-meter-long underground walkway. The dataset consisted of 60 samples (22 samples for "bacterial flora"), including variables such as "temperature (T)," "humidity (H)," "atmospheric pressure (A)," "traffic pedestrians (TP)," "number of inorganic particles (Δ5: 1-5 μm)," "number of live airborne bacteria," and "bacterial flora." Our PCA with these environmental factors (T, H, A, and TP) revealed that the 60 samples could be categorized into four groups (G1 to G4), primarily based on variations in PC1 Loadings: T(-0.62), H(-0.647), TP(0.399), A(0.196) and PC2 Loadings: A(-0.825), TP(0.501), H(0.209), T(-0.155). Notably, the number of inorganic particles significantly increased from G4 to G1, but the count of live bacteria was highest in G2, with no other clear pattern. Further analysis with Glm2 indicated that changes in inorganic particles could largely be explained by two variables (H/TP), while live bacteria levels were influenced by all explanatory variables (TP/A/H/T). ANOVA tests confirmed that inorganic particles and live bacteria were influenced by different factors. Moreover, there were minimal changes in bacterial flora observed among the groups (G1-G4). In conclusion, our findings suggest that the dynamics of live bacteria in the underground walkway differ from those of inorganic particles and are regulated in a complex manner by multiple environmental factors. This discovery may contribute to improving public health in urban settings.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Healthcare-associated infections have become a major health issue worldwide. One route of transmission of pathogenic bacteria is through contact with “high-touch” dry surfaces, such as handrails. ...Regular cleaning of surfaces with disinfectant chemicals is insufficient against pathogenic bacteria and alternative control methods are therefore required. We previously showed that warming to human-skin temperature affected the survival of pathogenic bacteria on dry surfaces, but humidity was not considered in that study. Here, we investigated environmental factors that affect the number of live bacteria on dry surfaces in hospitals by principal component analysis of previously-collected data (
n
= 576, for CFU counts), and experimentally verified the effect of warming to human-skin temperature on the survival of pathogenic bacteria on dry surfaces under humidity control. The results revealed that PCA divided hospital dry surfaces into four groups (Group 1~4) and hospital dry surfaces at low temperature and low humidity (Group 3) had much higher bacterial counts as compared to the others (Group 1 and 4) (
p
<0.05). Experimentally, warming to human-skin temperature (37°C with 90% humidity) for 18~72h significantly suppressed the survival of pathogenic bacteria on dry surfaces, such as plastic surfaces
p
<0.05 vs. 15°C (
Escherichia coli
DH5α,
Staphylococcus aureus
,
Pseudomonas aeruginosa
,
Acinetobacter baumannii
, and
bla
NDM-5
E
.
coli
) or handrails p<0.05 vs. 15~25°C (
E
.
coli
DH5α,
S
.
aureus
,
P
.
aeruginosa
,
A
.
baumannii
), under moderate 55% humidity. Furthermore, intermittent heating to human-skin temperature reduced the survival of spore-forming bacteria (
Bacillus subtilis
) (
p
<0.01 vs. continuous heating to human-skin temperature). NhaA, an Na
+
/H
+
antiporter, was found to regulate the survival of bacteria on dry surfaces, and the inhibitor 2-aminoperimidine enhanced the effect of warming at human-skin temperature on the survival of pathogenic bacteria (
E
.
coli
DH5α,
S
.
aureus
,
A
.
baumannii
) on dry surfaces. Thus, warming to human-skin temperature under moderate humidity is a useful method for impairing live pathogenic bacteria on high-touch surfaces, thereby helping to prevent the spread of healthcare-associated infections.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The spreading of antimicrobial-resistant Enterobacteriaceae, especially those co-harboring plasmid-mediated cephalosporin (bla) and colistin (mcr) resistance genes, is becoming increasingly ...problematic. As a vector, flies carry antimicrobial-resistant bacteria (ARB) into human and livestock habitats. To investigate ARB in flies, we collected 235 flies from 27 sites (18 urban areas, five pig farms and four chicken farms) in Thailand during 2013-2015. Cefotaxime-resistant Enterobacteriaceae (CtxRE) and bla-positive CtxRE were isolated from 70 (29.8%) and 48 (20.4%) flies, respectively. In 93 bla-positive CtxRE isolates that included Escherichia coli, Enterobacter spp., and Klebsiella pneumoniae from 48 flies, the most frequent bla gene was TEM (n = 62), followed by CTX-M-55 (n = 31), CTX-M-14 (n = 26), CMY-2 (n = 24) and SHV (n = 10), and 58 isolates harbored multiple types of these genes. In addition, we detected the mcr-1 (n = 1) and mcr-3 (n = 19) genes in bla-positive CtxRE isolates from 16 flies. In conjugation experiments, 10 mcr-3- and bla-positive isolates exhibited co-transfer of mcr-3 and blaTEM-1 genes. These results suggest that a relatively high proportion of flies in Thailand carries cephalosporin-resistant Enterobacteriaceae harboring co-transmissible cephalosporin and colistin resistance genes.
We monitored the survival of human pathogenic bacteria Escherichia coli (ATCC), extended-spectrum β-lactamase-producing E. coli (Clinical isolate), New Delhi metallo-β-lactamase-producing E. coli ...(clinical isolate), Staphylococcus aureus (ATCC) on dry materials (vinyl chloride, aluminum, plastic, stainless steel) at distinct temperatures (room temperature or 15°C-37°C). These bacteria favored a lower temperature for their prolonged survival on the dry fomites, regardless of the material type. Interestingly, when mixed with S. aureus, E. coli survived for a longer time at a lower temperature. Cardiolipin, which can promote the survival of S. aureus in harsh environments, had no effect on maintaining the survival of E. coli. Although the trends remained unchanged, adjusting the humidity from 40% to 60% affected the survival of bacteria on dry surfaces. Scanning electron microscopic analysis revealed no morphological differences in these bacteria immediately before or after one day of dry conditions. In addition, ATP assessment, a method used to visualize high-touch surfaces in hospitals, was not effective at monitoring bacterial dynamics. A specialized handrail device fitted with a heater, which was maintained at normal human body core temperature, successfully prohibited the prolonged survival of bacteria Enterococcus faecalis (ATCC), E. coli (ATCC), Pseudomonas aeruginosa (ATCC), S. aureus (ATCC), Acinetobacter baumannii (clinical isolate), and Serratia marcescens (clinical isolate), with the exception of spore-forming Bacillus subtilis (from our laboratory collection) and the yeast-like fungus Candida albicans (from our laboratory collection) on dry surfaces. Taken together, we concluded that the tested bacteria favor lower temperatures for their survival in dry environments. Therefore, the thermal control of dry fomites has the potential to control bacterial survival on high-touch surfaces in hospitals.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chlamydia trachomatis LGV (CtL2) causes systemic infection and proliferates in lymph nodes as well as genital tract or rectum producing a robust inflammatory response, presumably leading to a low ...oxygen environment. We therefore assessed how CtL2 growth in immortal human epithelial cells adapts to hypoxic conditions. Assessment of inclusion forming units, the quantity of chlamydial 16S rDNA, and inclusion size showed that hypoxia promotes CtL2 growth. Under hypoxia, HIF-1α was stabilized and p53 was degraded in infected cells. Moreover, AKT was strongly phosphorylated at S473 by CtL2 infection. This activation was significantly diminished by LY-294002, a PI3K-AKT inhibitor, which decreased the number of CtL2 progeny. HIF-1α stabilizers (CoCl2, desferrioxamine) had no effect on increasing CtL2 growth, indicating no autocrine impact of growth factors produced by HIF-1α stabilization. Furthermore, in normoxia, CtL2 infection changed the NAD+/NADH ratio of cells with increased gapdh expression; in contrast, under hypoxia, the NAD+/NADH ratio was the same in infected and uninfected cells with high and stable expression of gapdh, suggesting that CtL2-infected cells adapted better to hypoxia. Together, these data indicate that hypoxia promotes CtL2 growth in immortal human epithelial cells by activating the PI3K-AKT pathway and maintaining the NAD+/NADH ratio with stably activated glycolysis.
Houseflies are a mechanical vector for various types of bacteria, including antimicrobial-resistant bacteria (ARB). If the intestine of houseflies is a suitable site for the transfer of antimicrobial ...resistance genes (ARGs), houseflies could also serve as a biological vector for ARB. To clarify whether cephalosporin resistance genes are transferred efficiently in the housefly intestine, we compared with conjugation experiments in vivo (in the intestine) and in vitro by using Escherichia coli with eight combinations of four donor and two recipient strains harboring plasmid-mediated cephalosporin resistance genes and chromosomal-encoded rifampicin resistance genes, respectively. In the in vivo conjugation experiment, houseflies ingested donor strains for 6 hr and then recipient strains for 3 hr, and 24 hr later, the houseflies were surface sterilized and analyzed. In vitro conjugation experiments were conducted using the broth-mating method. In 3/8 combinations, the in vitro transfer frequency (Transconjugants/Donor) was ≥1.3 × 10(-4); the in vivo transfer rates of cephalosporin resistance genes ranged from 2.0 × 10(-4) to 5.7 × 10(-5). Moreover, cephalosporin resistance genes were transferred to other species of enteric bacteria of houseflies such as Achromobacter sp. and Pseudomonas fluorescens. These results suggest that houseflies are not only a mechanical vector for ARB but also a biological vector for the occurrence of new ARB through the horizontal transfer of ARGs in their intestine.
We previously isolated a symbiotic environmental amoeba, harboring an environmental chlamydia, Neochlamydia S13. Interestingly, this bacterium failed to survive outside of host cells and was ...immediately digested inside other amoebae, indicating bacterial distribution via cytokinesis. This may provide a model for understanding organelle development and chlamydial pathogenesis and evolution; therefore, we assessed our hypothesis of Neochlamydia S13 distribution via cytokinesis by comparative analysis with other environmental Chlamydiae (Protochlamydia R18 and Parachlamydia Bn9). Dual staining with 4′,6‐diamidino‐2‐phenylindole and phalloidin revealed that the progeny of Neochlamydia S13 and Protochlamydia R18 existed in both daughter cells with a contractile ring on the verge of separation. However, in contrast to other environmental Chlamydiae, little Neochlamydia S13 16S ribosomal DNA was amplified from the culture supernatant. Interestingly, Neochlamydia S13 failed to infect aposymbiotic amoebae, indicating an intimate interaction with the host cells. Furthermore, its infectious rates in cultures expanded from a single amoeba were always maintained at 100%, indicating distribution via cytokinesis. We concluded that unlike other environmental Chlamydiae, Neochlamydia S13 has a unique ability to divide its progeny only via host amoebal cytokinesis. This may be a suitable model to elucidate the mechanism of cell organelle distribution and of chlamydial pathogenesis and evolution.
The role of lymphocytes as a cornerstone of the inflammatory response in the invasive pathogenesis
of Chlamydia trachomatis
(Ct) LGV (L1–3) infection is unclear. Therefore, we assessed whether the ...adaptation of CtL2 to immortal lymphoid Jurkat cells under hypoxic conditions occurred through proinflammatory cytokine profile modification. The quantities of inclusion-forming units with chlamydial 16S rDNA confirmed that CtL2 grew well under hypoxic rather than normoxic conditions in the cells. Confocal microscopic imaging and transmission electron microscopy revealed the presence of bacterial progeny in the inclusions and showed that the inclusions were larger under hypoxic rather than normoxic conditions; this was supported by the results of 3D image construction. Furthermore, PCR-based analysis of proinflammatory cytokines revealed that the gene expression levels under hypoxic conditions were significantly higher than those under normoxic conditions. In particular, the expression of two genes (
CXCL8
and
CXCR3
) was significantly diminished under normoxic conditions. Taken together, the results indicated that hypoxia promoted CtL2 growth in Jurkat cells while maintaining the levels of proinflammatory cytokines. Thus, Ct LGV infection in lymphocytes under hypoxic conditions might be crucial to a complete understanding of the invasive pathogenesis.
The Marabou stork (Leptoptilos crumenifer) is a typical scavenging bird and adapted to the Savannah environment, where they show a carnivorous feeding style. However, Marabou stork recently ...penetrated into the city areas and acclimatized to the urban environment, where they modified their feeding habits to an omnivorous type toward more carbohydrate. To reveal their adaptation to the variable feeding customs, this study compared the gut microbiomes and chemical compositions of feces of Marabou storks inhabiting two different locations in peri urban Kampala: one is a slaughter house floc that predicted their original carnivorous feeding, and the other is a landfill floc that adapted more to the omnivorous feeding. 16S rRNA gene sequencing analysis revealed more diverse gut microbiome, more enriched Lactobacilli, and less abundant Peptostreptococci in the landfill flock comparing to the slaughter house flock. Isolation work and predicted metagenome analysis confirmed more diverse Lactobacilli and more enriched functions for carbohydrate metabolism in the landfill flock. In addition, chemical composition of feces revealed higher ammonia in the former, which is consisting with higher Peptostreptococci and their practice of carnivorous feeding. These results highlighted their adaptation to the variable feeding environment, which presumably protects their health and ensure survival of species.
This study was conducted to understand the molecular epidemiology of circulating Chlamydia trachomatis (Ct) strains in Sapporo, Japan.
A total of 713 endocervical samples collected from April 2016 to ...March 2019 were screened for Ct. The obtained Ct positive samples were analyzed by ompA genotyping and multilocus sequence analysis (MLSA).
Eighty-three (11.6%) samples were positive for Ct plasmid DNA. Sequence analysis of the ompA gene from the 61 positive cases revealed eight genotypes: F (40.9%), E (19.6%), D (14.7%), G (9.8%), H (6.5%), I (3.2%), K (3.2%), and J (1.6%). The globally dominant genotype E and F strains were highly conserved with 13 ompA genetic variants being detected, whereas genotype D strains were the most diverse. Genetic characterization of D strains revealed that D1 genetic variants may be potentially specific to Sapporo. MLSA revealed 13 unique sequence types (STs) including four novel STs from 53 positive samples, with the globally dominant STs 39 and 19 being predominant. STs 39, 34, and 21 were exclusively associated with genotypes E and F indicating their global dominance. Novel ST70 and ST30 were specifically associated with genotype D.
Our study has revealed the circulation of genetically diverse Ct strains in the women population of Sapporo, Japan. We suggest identifying a transmission network of those successful strains and implementing public health prevention strategies to control the spread of Ct in Sapporo.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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