Persistence of Marine Bacterial Plasmid in the House Fly (Musca domestica): Marine-Derived Antimicrobial Resistance Genes Have a Chance of Invading the Human Environment

The house fly is known to be a vector of antibiotic-resistant bacteria (ARB) in animal farms. It is also possible that the house fly contributes to the spread of ARB and antibiotic resistance genes (ARGs) among various environments. We hypothesized that ARB and ARGs present in marine fish and fishery food may gain access to humans via the house fly. We show herein that pAQU1, a marine bacterial ARG-bearing plasmid, persists in the house fly intestine for 5 days after fly ingestion of marine bacteria. In the case of Escherichia coli bearing the same plasmid, the persistence period exceeded 7 days. This interval is sufficient for transmission to human environments, meaning that the house fly is capable of serving as a vector of marine-derived ARGs. Time course monitoring of the house fly intestinal microflora showed that the initial microflora was occupied abundantly with Enterobacteriaceae. Experimentally ingested bacteria dominated the intestinal environment immediately following ingestion; however, after 72 h, the intestinal microflora recovered to resemble that observed at baseline, when diverse genera of Enterobacteriaceae were seen. Given that pAQU1 in marine bacteria and E. coli were detected in fly excrement (defined here as any combination of feces and regurgitated material) at 7 days post-bacterial ingestion, we hypothesize that the house fly may serve as a vector for transmission of ARGs from marine items and fish to humans via contamination with fly excrement.

Marine bacteria harbor the sulfonamide resistance gene sul4 without mobile genetic elements

Marine bacteria are possible reservoirs of antibiotic-resistance genes (ARGs) originating not only from clinical and terrestrial hot spots but also from the marine environment. We report here for the first time a higher rate of the sulfonamide-resistance gene sul4 in marine bacterial isolates compared with other sul genes. Among four sulfonamide-resistance genes (sul1, sul2, sul3, and sul4), sul4 was most abundant (45%) in 74 sulfonamide-resistant marine isolates by PCR screening. The order of abundance was sul4 (33 isolates) >sul2 (6 isolates) >sul3 (5 isolates) >sul1 (1 isolate). Whole-genome sequencing of 23 isolates of sul4-expressing α- and γ-proteobacteria and bacilli revealed that sul4 was not accompanied by known mobile genetic elements. This suggests that sul4 in these marine isolates is clonally transferred and not horizontally transferable. Folate metabolism genes formed a cluster with sul4, suggesting that the cluster area plays a role in folate metabolism, at which sul4 functions as a dihydropteroate synthase. Thus, sul4 might be expressed in marine species and function in folate synthesis, but it is not a transferable ARG.

An Integrative and Conjugative Element (ICE) Found in Shewanella halifaxensis Isolated from Marine Fish Intestine May Connect Genetic Materials between Human and Marine Environments

Integrative and conjugative elements (ICEs) play a role in the horizontal transfer of antibiotic resistance genes (ARGs). We herein report an ICE from Shewanella halifaxensis isolated from fish intestine with a similar structure to both a clinical bacterial ICE and marine bacterial plasmid. The ICE was designated ICEShaJpn1, a member of the SXT/R391 family of ICEs (SRIs). ICEShaJpn1 has a common core structure with SRIs of clinical and fish origins and an ARG cassette with the pAQU1 plasmid of Photobacterium damselae subsp. damselae, suggesting that the common core of SRIs is widely distributed and ARG cassettes are collected from regional bacteria.

Contamination of antibiotics and sul and tet(M) genes in veterinary wastewater, river, and coastal sea in Thailand

Water systems in Southeast Asia accumulate antibiotics and antibiotic resistance genes (ARGs) from multiple origins, notably including human clinics and animal farms. To ascertain the fate of antibiotics and ARGs in natural water environments, we monitored the concentrations of these items in Thailand. Here, we show high concentrations of tetracyclines (72,156.9 ng/L) and lincomycin (23,968.0 ng/L) in pig farms, followed by nalidixic acid in city canals. The city canals and rivers contained diverse distributions of antibiotics and ARGs. Assessments of targeted ARGs, including sul1, sul2, sul3, and tet(M), showed that freshwater (pig farm wastewater, rivers, and canals) consistently contained these ARGs, but these genes were less abundant in seawater. Although sulfonamides were low concentrations (<170 ng/mL), sul1 and sul2 genes were abundant in freshwater (minimum 4.4 × 10^-3-maximum 1.0 × 10⁰ copies/16S), suggesting that sul genes have disseminated over a long period, despite cessation of use of this class of antibiotics. Ubiquitous distribution of sul genes in freshwater appeared to be independent of selection pressure. In contrast, water of the coastal sea in the monitored area was not contaminated by these antibiotics or ARGs. The density of Enterobacteriales was lower in seawater than in freshwater, suggesting that the number of ARG-possessing Enterobacteriales falls after entering seawater. From the pig farms, through rivers/canals, to the coastal sea, the occurrence of tetracyclines and tet(M) exhibited some correlation, although not a strong one. However, no correlations were found between concentrations of total antibiotics and ARGs, nor between sulfonamides and sul genes. This is the first comprehensive study showing Thai features of antibiotics and ARGs contaminations. The pig farm is hot spot of antibiotics and ARGs, and sul genes ubiquitously distribute in freshwater environments, which become less abundant in seawater.

Adsorption of sulfonamides to marine diatoms and arthropods

Sulfonamides are frequently detected in the environment, where these compounds adsorb to soil particles and are retained in the environment. However, adsorption of sulfonamides to planktonic particles in the sea is not known. Here we demonstrate that sulfonamides adsorb to a diatom (Chaetoceros) and an arthropod (Artemia), albeit at low levels, under laboratory conditions. In both plankton, sulfamethazine (SMT) was more readily adsorbed than was sulfamethoxazole (SMX). The adsorption occurred quickly and the concentration on the plankton was stable for at least 24 h (Chaetoceros) or 5 h (Artemia). These data suggest that marine plankton may retain sulfonamides, although the adsorbed concentration per cell or individual is not high.

Tetracycline Resistance Gene Profiles in Red Seabream (Pagrus major) Intestine and Rearing Water After Oxytetracycline Administration

Marine aquaculture fish and the environment are possible hot spots for the maintenance and spread of antibiotic resistance genes (ARGs). We here show the time courses of changes of six tetracycline resistance genes (tet) in fish rearing seawater and fish intestine in tank experiments. Experimental tanks were prepared as oxytetracycline (OTC) administration tanks and those without OTC. It was found that tet(B), tet(M), and tet(W) were dominant in seawater among the six tet genes. tet(B) and tet(M) abundances increased immediately after OTC administration, indicating that OTC served as a selective pressure to increase the proportion of tet-possessing bacteria. In contrast, the abundance of tet genes in the fish intestine did not differ between the with- and without-OTC administration groups, and clearly was not altered by OTC administration. Profile changing of tet in seawater and fish intestine did not synchronize. These observations suggested that the dynamics of intestinal tet-possessing bacteria do not directly reflect the environment, but reflect selection within the intestine.

Tetracycline resistance gene tet(M) of a marine bacterial strain is not accumulated in bivalves from seawater in clam tank experiment and mussel monitoring

Antibiotic resistance genes (ARGs) are found in marine as well as terrestrial bacteria. Bivalves are known to accumulate chemical pollutants and pathogenic microbes, however, the fate of ARGs in bivalves after the intake of ARG-possessing bacteria is not known. Here we show that the copy number of oxytetracycline resistance gene tet(M) increased rapidly in the clam digestive tract by filtering water, then remained constant over 96h in a tank experiment even with the addition of tet(M)-possessing bacteria every 24h. >99.9% of the added tet(M) was decomposed, reaching a balanced state. Environmental sampling of mussel digestive tract and seawater supported the hypothesis that tet(M) was decomposed in bivalves as tet(M) was present in seawater from April to October at a concentration of 10^-5 to 10^-6 copies/16S, whereas tet(M) in mussels was mostly below the detection limit. Two (April) and three (July and October) individual mussels were positive for tet(M) with a concentration equivalent to that of seawater. We therefore conclude that bivalves do not accumulate tet(M) from seawater.

Efficacy of sulfamethoxazole-trimethoprim administration in the prevention of Pneumocystis carinii pneumonia in patients with connective tissue disease

The efficacy and adverse effects of prophylactic administration of Sulfamethoxazole-Trimethoprim (ST) for Pneumocystis carinii Pneumonia (PCP) were assessed in patients with connective tissue diseases (CTD). Eighty-four patients who were receiving more than 40 mg/day of prednisolone were entried in the present study. Patients with at least one of the two PCP risk factors (interstitial pulmonary fibrosis and lymphopenia), were administered either one (11 patients) or two (26 patients) ST tablets/day. The remaining 47 patients who did not receive ST served as the controls. Although PCP was detected in 4.3% of the patients in the no-ST group, none of the patients who received ST developed PCP. Five of these 26 patients who received two tablets of ST/day, experienced adverse reactions. However, no adverse reactions were detected in the patients who received one tablet of ST/day (p < 0.05). Abnormal laboratory data were obtained for 10 (38.5%) of the patients who received two tablets of ST/day and for 4 (36.4%) of the 11 patients who received one tablet of ST/day. The results of the present study suggest that the prophylactic administration of one tablets of ST in patients with CTD that have at least one of the two PCP risk factors is effective in preventing PCP.

[A SLE case with toxic shock syndrome after delivery]

We experienced a SLE patient with TSS after delivery. A 32-year-old SLE patient was transferred to our division due to fever, diarrhea, erosive rash, pericardial effusion, myalgia, low blood pressure, thrombocytopenia and hypoproteinemia which appeared two days after transvaginal delivery. At the time of admission, we considered these symptoms as the exacerbation of SLE, and treatment with high doses of steroid was started. It was when TSST-1-producing-MRSA was cultured from the vagina and uterus that TSS was suspected. 2 g/day of vancomycin was administered and her symptoms improved. As observed in this case, it is important to consider TSS as one of the complications seen with SLE patients after delivery.

[Serum hepatocyte growth factor (HGF) in patients with inflammatory myopathies]

The hepatocyte growth factor (HGF) regulates growth, motility, and morphogenesis of epithelial and endothelial cells. It has been reported that serum level of HGF was elevated in patients with having fulminant hepatitis. In inflammatory myopathies (IM), muscle cells are damaged by the inflammatory process and subsequently regenerated. HGF may be involved in the regeneration process of muscle cells in IM. We examined serum HGF was measured by ELISA from 13 patients with having polymyositis (PM), 18 patients with having dermatomyositis (DM), 3 patients with amyopathic dermatomyositis (ADM) and 14 normal individuals. The muscle of IM patients was examined by immunofluorescence staining using a monoclonal anti-HGF antibody. The serum HGF level was significantly higher in IM patients (0.63 +/- 0.11 (p = 0.028) in PM, 0.58 +/- 0.07 (p = 0.023) in DM) than in normal controls (0.26 +/- 0.01 ng/ml). However, there was no relationship between the serum HGF level and hepatic enzyme level in IM. The levels of serum HGF were significantly higher in active disease (1.05 +/- 0.26 ng/ml) than in inactive disease (0.29 +/- 0.03 ng/ml) (p = 0.044). The serum HGF levels (0.77 +/- 0.12 ng/ ml) were significantly higher in IM patients with pulmonary fibrosis than in those (0.42 +/- 0.04 ng/ml) without pulmonary fibrosis (p = 0.049). There was a positive relationship between serum HGF levels and the presence of opaque fiber and/or regeneration/degeneration fiber in biopsied muscles. HGF was detected in muscles from IM patients by immunofluorescence. Serum HGF levels are elevated in IM and correlated with disease activity and complication of interstitial pneumonia.

Risk factors for Pneumocystis carinii pneumonia in patients with polymyositis/dermatomyositis or systemic lupus erythematosus

OBJECTIVE

To investigate risk factors for Pneumocystis carinii pneumonia (PCP) in patients with systemic lupus erythematosus (SLE) and polymyositis/dermatomyositis (PM/DM).

METHODS

The subjects were 75 patients hospitalized because of SLE or PM/DM who were administered corticosteroids 40 mg/day or above as prednisolone. The relationship between clinical symptoms of SLE and PM/DM and the occurrence of PCP was evaluated.

RESULTS

Seven patients (9.3%) developed PCP and 3 died. Interstitial pulmonary fibrosis was observed in all 7 patients who developed PCP, and its incidence was significantly higher (p < 0.001) than in those who did not develop PCP (6/68). The incidence of PCP in patients with SLE was 1.7%, but that of patients with PM/DM was 37.5%. The peripheral blood lymphocyte count was 1052.7/microliters in patients who developed PCP, which was significantly lower (p < 0.01) than 1841.6/microliters in patients who did not develop PCP.

CONCLUSION

A low peripheral lymphocyte count and interstitial pulmonary fibrosis were considered risk factors for PCP in patients administered corticosteroids for SLE or PM/DM.

Acquired progressive lymphangioma occurring following femoral arteriography

Our case report concerns an unusual case of acquired progressive lymphangioma (APL) which developed in a 52-year-old Japanese man following femoral artery catheterization for angiography. The histological examination revealed many irregularly shaped and dilated lymphatic channels that were lined by a single layer of endothelial cells. Immunohistochemical staining for von Willebrand factor was negative in the endothelial cells of the dilated channels. Electron microscopic study demonstrated no Weibel-Palade bodies in the cytoplasm of the endothelial cells. The endothelial cells had no distinct basement membrane.

Cutaneous vasculitis in a patient with dermatomyositis without muscle involvement

A 74-year-old female patient with cutaneous ulcerations and typical dermatomyositis (DM) skin rash had no muscle disease for a 1-year and 5 months period. Histological examination of the skin ulceration indicated vascular occlusion without cellular infiltration. Cutaneous ulceration is a very rare manifestation of adult-onset DM patients without inflammatory myopathy.

Assignment of the human indoleamine 2,3-dioxygenase gene to chromosome 8 using the polymerase chain reaction

In order to identify the chromosomal assignment for the human indoleamine 2,3-dioxygenase (IDO) gene, we performed the polymerase chain reaction (PCR) using somatic cell hybrids and screened for the presence of amplified products. The results indicate that the human IDO gene can be assigned to chromosome 8.

Nevus depigmentosus systematicus with partial yellow scalp hair due to selective suppression of eumelanogenesis

We report a Japanese patient with congenital hypomelanosis with a segmental pattern on the left abdomen, whorl-like pattern on the back; mosaic pattern on the chest, right abdomen, and proximal extremities; and with yellow hair on a portion of the scalp. Chemical analysis of the yellow hair revealed decreased eumelanin content, whereas the pheomelanin content was normal.

Chédiak-Higashi syndrome: report of a case and review of the Japanese literature

We report the case of a Japanese female infant with Chédiak-Higashi syndrome born to consanguineous parents. At birth she had fair skin but, when she was three months old, marked hyperpigmentation of the sun-exposed skin areas developed. Microscopic examination of blood and electron microscopic examination confirmed the diagnosis. She enjoyed good health until she was two years old when she had pneumonia with marked hepatosplenomegaly. It is important for dermatologists and pediatricians to be aware of the skin manifestations of this disease because hyperpigmentation after sun exposure may be a characteristic, initial feature of this condition.

Gene structure of human indoleamine 2,3-dioxygenase

Two genomic DNA clones that encode human indoleamine 2,3-dioxygenase (IDO) were isolated from the human genomic DNA library using the IDO cDNA as a probe, and their restriction maps and partial nucleotide sequences were determined. The human IDO gene spanned 15 kilobase pairs with ten exons. The 5' terminus of the IDO mRNA was 33 nucleotides upstream of the translation initiation codon ATG. The 5' flanking region contained ISRE, X-box, and Y-box like sequences. Southern blot analysis of the human genomic DNA indicated that the human IDO gene was present in a single copy in the genome.