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PubMed1994

Complement sensitivity of Entamoeba histolytica and various nonpathogenic amoeba species.

Culture forms of the potentially pathogenic Entamoeba histolytica were compared to those of the nonpathogenic species of E. dispar, E. hartmanni, E. coli, Endolimax nana, and E. moshkovskii regarding the sensitivity to lysis by human complement activated through the alternative pathway. E. dispar was found unique in its complement resistance; all other nonpathogenic isolates resembled E. histolytica in that they were complement sensitive. Thus, a state of complement sensitivity is not a particular property of potentially pathogenic amoebae.

Animals↗
PubMed2004

An assay to compare the infectivity of Mycobacterium tuberculosis isolates based on aerosol infection of guinea pigs and assessment of bacteriology.

The aim of this study was to establish an assay to compare Mycobacterium tuberculosis strains, and cells grown under different growth conditions, in terms of their ability to cause a lung infection and disseminate to the spleen. M. tuberculosis strains H37Rv, Erdman, South Indian (TMC120, SI) and H37Rv cells grown aerobically or under low oxygen/iron limitation in a chemostat were assayed for infectivity. Groups of 8 animals were challenged with 3 different doses of each strain. Lung and spleen bacteriology was assessed at 16 days post-infection for all strains. Bacteriology and lung pathology at day 56 was studied for H37Rv, Erdman and SI. Strains H37Rv and Erdman had a statistically significantly higher pathogenic potential than SI and this was confirmed by analysis of lung pathology performed at 8 weeks post-infection, although the Erdman strain caused more extensive caseation without calcification and little encapsulation. The model could discriminate between cells grown under different growth conditions; low-oxygen/iron-limited cells had a significantly higher infectivity than those grown aerobically. This study presents a quick and reliable method for comparing with statistical confidence, the pathogenic potential of M. tuberculosis strains and the impact of in vitro growth conditions on the infectivity of M. tuberculosis in vivo.

Aerobiosis↗
PubMed1996

Molecular and pathogenic characterization of the RFB osteoma virus: lack of oncogene and induction of osteoma, osteopetrosis, and lymphoma.

RFB virus is an ecotropic C-type retrovirus isolated from CF-1 mice, in which it is associated with induction of osteomas. Sequence analysis of the RFB provirus revealed no evidence for presence of an oncogene or a recombined env gene. RFB virus is a member of the murine leukemia virus (MuLV) group (RFB MuLV), sharing 97% nucleotide identity with the endogenous ecotropic provirus of AKR mice (Akv). Like Akv, expression of RFB MuLV mRNAs is inducible by dexamethasone treatment, indicating that FRB MuLV also shares transcriptional control signals with Akv. We assessed the pathogenic potential of RFB MuLV in NMRI mice, which, in contrast to CF-1 mice, do not contain endogenous ecotropic retroviruses. RFB MuLV induced osteomas, osteopetrosis, and lymphomas in newborn NMRI mice. Another CF-1 mouse-derived leukemia virus, FBJ MuLV, the helper virus of the FBJ osteosarcoma virus stock, as well as Akv, also induced osteomas, osteopetrosis, and lymphomas in NMRI mice similar to RFB MuLV. These findings indicate that endogenous retroviruses carry a pathogenic potential in hematopoietic tissues and in the skeleton.

Animals↗
PubMed1999

Airway inflammation and bronchial microbial patterns in patients with stable chronic obstructive pulmonary disease.

The effect of bacterial colonization of the bronchi on the progress of airflow limitation is not well known. Therefore, the pattern of airway inflammation in smokers and patients with stable chronic obstructive pulmonary disease (COPD) and its relation to bronchial microbial colonization was assessed. Eight nonsmoking and 18 smoking controls as well as 52 patients with COPD (28 mild, 11 moderate and 13 severe) were studied. All subjects were investigated by means of flexible bronchoscopy including protected specimen brush and bronchoalveolar lavage (BAL) sampling. Differential cell counts, cytokine (interleukin (IL)-1beta, IL-6, IL-8, IL-10 and tumour necrosis factor-alpha(TNF-alpha) concentrations and microbial patterns were determined in BAL fluid. Forced expiratory volume in one second (FEV1) % of the predicted value was inversely correlated with pack-yrs of cigarette smoking (r=-0.47, p<0.0001), the percentage of neutrophil (p=-0.56, p<0.0001) and IL-6 (p=-0.37, p=0.01) and IL-8 concentration (p=-0.43, p=0.004) in BAL fluid. Accordingly, pk-yrs of cigarette smoking (p=0.39, p=0.01) and IL-8 (p=0.69, p<0.0001) and TNFalpha (p=0.4, p<0.005) were positively correlated with the percentage of neutrophils in BAL fluid. Smoking controls and COPD patients were mainly colonized in the bronchial tree (33%) by community endogenous potentially pathogenic micro-organisms (PPMs). Colonization rates and patterns of PPMs were not affected by severity of airflow obstruction. The presence of PPMs was significantly associated with higher percentages of neutrophils (33.2+/-10.4% versus 10.1+/-3.5%, p=0.02) and TNF-alpha concentration (29.9+/-10.8 versus 6.3+/-2.1 pg x mL(-1), p=0.01) in BAL fluid. In conclusion, bronchial neutrophilia is a key inflammatory pattern in chronic obstructive pulmonary disease patients. Bronchial colonization with potentially pathogenic micro-organisms may represent an independent stimulus for additional airway inflammation.

Biopsy↗
PubMed1998

Peripheral blood lymphocytes in SLE--hyperexpression of CD154 on T and B lymphocytes and increased number of double negative T cells.

Abnormalities in the regulation of both cell-mediated and humoral immunity have been implicated in the pathophysiology of systemic lupus erythematosus (SLE). Cognate contact-dependent T-B cell interactions involving CD154 (CD40 ligand) on activated T cells and CD40 on B lymphocytes have a critical role in antibody production. Abnormal CD154 expression on lymphocytes may play a role in the production of potentially pathogenic autoantibodies and defects in self-tolerance mechanisms may be important. Failure of intrathymic or peripheral deletion of autoreactive T cells may also result in an autoimmune phenotype. Elevated levels of CD3(+)CD4(-)/8(-) (double negative) T cells (DNT) in the peripheral blood are a surrogate marker for defects of this type. The expression of CD154 on T and B cells was evaluated and levels of double negative T cells in the peripheral blood were assessed by two and three colour flow cytometric analyses. We studied peripheral blood lymphocytes in 48 patients with SLE. Twenty-five normal subjects and 12 patients with rheumatoid arthritis (RA) were studied as disease controls. T cells in 22/48 (45%) lupus patients expressed CD154 between 20-80% (median=52%). In normal controls and RA patients 8-18% T cells were CD154(+). Twelve patients (30%) had elevated expression of CD154 (20-50%) on B cells. In the control RA patients, less than 15% T cells were CD154(+). Twelve of 48 SLE patients had elevated numbers of DNT cells (18-27%). The control subjects had DNT cell numbers <10. These observations suggest that defects in either the intrathymic or peripheral deletion of potentially pathogenic T lymphocytes may play a role in the pathogenesis of SLE. The high expression of CD154 on both T and B cells may also be important in mediating the production of potentially harmful autoantibodies.

Adult↗
PubMed1996

Isolation of yeasts from bovine milk in Belgium.

A total of 436 milk samples from non-infected and 80 from infected quarters were investigated: 24.5% of the samples collected from non-infected and 55% of those collected from infected quarters were positive. Normal milk yielded not less than 16 different species and among them many potentially pathogenic yeast species such as C. parapsilosis, C. guilliermondii, C. tropicalis, C. glabrata and T. asahii, all five able to grow at 40 degrees C. In contrast, the yeasts isolated from infected quarters were from 3 species: C. kefyr, C. catenulata and C. lambica, which were also among the yeasts species recovered from normal milk. Among the three species, only one i.e. Candida kefyr is able to grow above 40 degrees C and from there can be considered as potentially pathogenic, even if bacterial association is necessary to cause mastitis.

Animals↗
PubMed1986

Antibody coating and quantitative cultures of bacteria in sputum and bronchial brush specimens from patients with stable chronic bronchitis.

Antibody coating of bacterial isolates has been proposed as a method of identifying bacteria responsible for chronic lower respiratory infections. This study was designed to determine the specificity of antibody coating by examining bronchial secretions obtained from a group of patients with chronic bronchitis who had no clinical evidence of acute infection. Routine and quantitative bacterial cultures were performed at the same time. The bronchial brush specimens contained potentially pathogenic bacteria in all 18 patients examined, and 17 of these 18 specimens had antibody coating of bacteria. Quantitative cultures yielded greater than 10(4) colony forming units in only one patient and he subsequently developed a lower respiratory tract infection. We conclude that in patients with chronic bronchitis, the determination of antibody coating of bacterial isolates does not significantly increase the specificity of routine culture. Quantitative cultures of specimens obtained via the protected brush catheter are useful in identifying potential pathogens.

Bronchi↗
PubMed2006

Effect of telithromycin and azithromycin on nasopharyngeal bacterial flora in patients with acute maxillary sinusitis.

OBJECTIVE: To explore the efficacy of the ketolide telithromycin compared with azithromycin in eradicating S pneumoniae from the nasopharynx of adults with acute maxillary sinusitis. The growing resistance of Streptococcus pneumoniae to penicillin and macrolides brought about the development of a new class of antibiotics-the ketolides-that are effective against resistant pneumococci. SETTING: Otolaryngology clinic. PATIENTS: One-hundred five patients with acute maxillary sinusitis. INTERVENTIONS: Nasopharyngeal cultures were obtained before therapy and 10 to 12 days after initiation of treatment. Fifty-nine patients were treated with 500 mg of azithromycin daily for 3 days and 46 were treated with 800 mg of telithromycin daily for 5 days. RESULTS: Sixty-seven potential pathogens were recovered prior to initiation of therapy in 57 patients, 32 treated with telithromycin and 25 treated with azithromycin: S pneumoniae (31 isolates), Haemophilus influenzae (non-type b) (13), Staphylococcus aureus (8), Streptococcus pyogenes (8), and Moraxella catarrhalis (7). The distribution of the pathogens was similar in both groups. The number of S pneumoniae isolates in the azithromycin group was reduced following treatment from 14 to 8 (43% reduction), and 5 of these 8 isolates were resistant to azithromycin. In contrast, the number of S pneumoniae isolates in the telithromycin group was reduced following treatment from 17 to 1 (94% reduction) (P < .01). This isolate was susceptible to azithromycin and telithromycin. No differences were noted in the eradication rate of all of the other potential pathogens, which were all susceptible to both azithromycin and telithromycin. Development of resistance to the antimicrobial agents used (defined as increase in the minimal inhibitory concentration by at least 2 tubes) was found only in 5 isolates (4 S pneumoniae and 1 H influenzae) recovered only from patients who received azithromycin (P < .05). CONCLUSION: These data illustrate the superiority of telithromycin to azithromycin in the eradication of S pneumoniae from the nasopharynx.

Acute Disease↗
PubMed1988

Infections after experimental cadaver bone marrow transplantation in beagle dogs. Transplantations with and without selective gastrointestinal decontamination.

Experimental transplantations of cadaver bone marrow (BMT) in beagle dogs were performed to evaluate the problems and potentials in a preclinical setting. The effectiveness of selective decontamination of the gut (SD) and gnotobiotic surveillance in preventing infections during longer aplastic periods was investigated. Three groups of dogs were compared. Group A: controls. Group B: dogs with BMT, without SD and irregular gnotobiotic surveillance. Group C: dogs with BMT, with SD and regular gnotobiotic surveillance. The intestinal colonization of normal healthy beagles shows similarities as well as dissimilarities to the human intestinal microflora. Aerobic potentially pathogenic organisms do not colonize the gut of healthy beagles under our keeping conditions. SD resulted in a significant decrease in infections with Escherichia coli and Plesiomonas. Infections with anaerobes, as well as bacterial infections of the respiratory tract were, however, not prevented. The intestinal colonization in dogs of group C with Clostridium difficile is another obvious effect of SD. The infections encountered during the study indicate the importance of the "take" for the clinical significance and outcome of intestinal colonization with potentially pathogenic organisms. In order to reduce the drug burden of BMT patients, we consider the elimination of routine SD after BMT not to be superior to gnotobiotic surveillance and germ-specific short term decontamination.

Amphotericin B↗
PubMedDate not supplied

Ecophylaxis: preventive treatment with gentamicin of rabbit lincomycin-associated diarrhea.

In rabbits the oral or parenteral administration of lincomycin result in a severe and usually fatal form of diarrhea. The rabbits treated simultaneously with lincomycin and gentamicin do not present any sign of disease and behave exactly, therefore, as the control subjects. The same occurs in subjects treated with gentamicin alone. In all the subjects which died with diarrhea there was a marked alteration of the intestinal bacterial flora. Among the aerobic bacteria there was an overgrowth of coliforms and less frequently of enterococci, while bacilli were reduced and lactobacilli completely disappeared. Among the anaerobic bacteria, bacteroides and bifidobacteria disappeared and there was an overgrowth of clostridia instead. In rabbits treated contemporaneously with lincomycin and gentamicin, coliforms were absent and the mean number of clostridia was at least one hundred times lower; as in rabbits treated only with lincomycin, enterococci were present in greater number, while lactobacilli, bifidobacteria and bacteroides completely disappeared. Some of the bacteria which are able to overgrow in lincomycin treated subjects, in particular coliforms and clostridia, can be considered potentially pathogenic and their overgrowth could therefore explain the onset of diarrhea. Actually in faecal specimens of rabbits with lincomycin-associated diarrhea, together with the overgrowth of E. coli and clostridia, there is an absence of lactobacilli, bifidobacteria and bacteroides. It is known that these last bacteria contribute, in normal conditions, to maintaining the ecological equilibrium of the intestinal microbial flora. The diarrhea itself can be attributed most likely to the ecological alteration of intestinal microbial flora, with an overgrowth of some potentially pathogenic bacteria and the suppression of others which normally exert an inhibiting effect on the former. It has been suggested to call this form of gentamicin prophylaxis of lincomycin-associated diarrhea 'ecophylaxis', in the sense that it prevents or corrects certain types of ecological alteration of the intestinal microbial flora which lead to diarrhea.

Animals↗
PubMed1994

Serum antibody responses of divers to waterborne pathogens.

To assess the significance of exposure of divers to waterborne pathogens, specific immunoglobulin G serum antibody responses to Pseudomonas and Aeromonas isolates recovered from dive sites from the respiratory tracts of nine experienced divers and seven diving trainees working in the Chesapeake Bay area over a 6- to 18-month period were measured. A significant increase in the frequency of isolation of these organisms from respiratory surfaces both groups of divers after each dive was noted, with the divers' ears being the predominant recovery site (48%; P < 10(-8), chi-square). The acute serum responses of the majority of experienced divers (83%) showed evidence of preexisting antibody to these potential pathogens, whereas the acute serum response of only 32% of naive divers showed such evidence (P < 10(-8), chi-square). Six months into their training, the rate of seroresponse of the trainees to organisms recovered after their first dives increased to 61% (P = 0.003, chi-square), suggesting that repeated exposure in necessary for generation of a specific systemic immunologic response. The rate of acquisition of a new seroresponse to recovered organisms was approximately 12% per dive for both groups of divers, suggesting that there is continuous exposure to, and infection with, new strains present in the water during dives. These data suggest that, in cases in which systemic antibody is important for protection, there are various levels of susceptibility to waterborne potential pathogens in both experienced and inexperienced divers.

Adult↗
PubMed1990

[Antibody-coated bacteria and quantitative culture in sputum samples from patients with bronchiectasis].

The results of the quantitative culture of sputum samples from patients with bronchiectasis were compared with those obtained in the same samples with the detection of antibody-coated bacteria (ACB), in the acute phase of the disease (group I), after antibiotic therapy (group II), and in the phase of clinical stability (group III). In quantitative cultures at least one potentially pathogen species was isolated, at a concentration of greater than or equal to 10(6) colony forming units/ml in the 7 sputum samples from group I, in 4 of the 5 samples from group II, and in 10 of the 11 samples from group III. The immunofluorescence technique detected ACB in all samples from group I and group II, and in 10 of the 11 from group III. The sample from group III in which ACB were not detected was the same in which potentially pathogen organisms were not detected by culture.

Acute Disease↗
PubMed2006

Identification and antibiotic susceptibility of bacterial isolates from probiotic products available in Italy.

This study was carried out to assay the bacterial viability and the probable contamination of a range of probiotic products available in Italy and to test the susceptibility of the isolates. Eleven dried food supplements and five fermented functional foods were examined using different isolation media under standardized cultivation conditions. The identification was made by conventional phenotypic characteristics and biochemical tests. Among isolates from the probiotic products antibiotic susceptibility was detected using the E-test (ABBiodisk). Our results demonstrate that nine food supplements and two fermented foods claimed species which could not be isolated, whereas potential pathogens (i.e. Micromonas micros) were isolated. Lactobacilli displayed species-dependent antibiotic resistance. Atypical resistance occurred for penicillin in Lactobacillus acidophilus and Lactobacillus bulgaricus and for erythromycin in Lactobacillus lactis and Lactobacillus salivarius. A broad range of MICs was observed for cephalosporins and fluroquinolones. Aminoglycosides had poor activity against Lactobacillus isolates. Two of the four isolates of Bifidobacterium exhibited high resistance to trimethroprim/sulfametoxazole and to fluoroquinolones. Our results suggest that some probiotic products claim species that cannot always be isolated, and are sometimes contaminated by potential pathogens. Moreover, the probable transferable erythromycin or penicillin resistance among the lactobacilli isolated should be taken into account.

Anti-Bacterial Agents↗
PubMed2006

Nasal middle meatal specimen bacteriology as a predictor of the course of acute respiratory infection in children.

AIMS: To test our hypothesis that children with potentially pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae or Moraxella catarrhalis) in the nasal middle meatus might have more prolonged symptoms of acute respiratory infection than children without such bacteria, we conducted a prospective cohort study of such children. MATERIALS AND METHODS: We recruited prospectively child volunteers between 6 and 13 years of age with acute respiratory infections present for fewer than 10 days. Nasal middle meatal bacterial culture was taken with a rigid endoscope at enrollment and again after 3 weeks and evaluated for presence or absence of 3 potential pathogens: S. pneumoniae, H. influenzae and M. catarrhalis. The subsequent persistence of acute symptoms (nasal discharge: clear/colored, nasal obstruction and cough) was determined by means of a diary. Viral etiology was studied with polymerase chain reaction methods. RESULTS: The 82 children had had symptoms for an average of 4 days (range, 1-10) at entry, and viruses were detected in 54% (39 of 72). The endoscopic procedure and bacteriologic sampling succeeded in all cases. Thirty-eight children (46%) had at least 1 of the 3 pathogens in the middle meatus specimen. The children with nasal pathogens present at entry had a significantly longer mean duration of symptoms than those with nonpathogenic bacteria (difference, 3.6 days; 95% confidence interval, 0.7-6.5; P = 0.025). The effect remained significant after adjustment for age, sex, allergic symptoms and the presence of virus (adjusted relative hazard of delayed recovery, 2.0; 95% confidence interval, 1.1-3.6). CONCLUSIONS: We found that the use of endoscopic swab culture sampling from the nasal middle meatus is well-tolerated by children older than 6 years of age and that it can be useful in selected situations to determine pathogenic bacteria in the culture of these specimens.

Acute Disease↗
PubMed2004

Genetic screening for melanocortin-4 receptor mutations in a cohort of Italian obese patients: description and functional characterization of a novel mutation.

Mutations in the human melanocortin-4 receptor (MC4-R) gene may account for up to 5.8% of morbid nonsyndromic obesity. We have screened 120 unrelated obese patients for variants of the MC4-R gene. Four heterozygous missense variants were detected, including two polymorphisms (Val(103)Ile and Ile(251)Leu) previously described in the literature. A novel heterozygous mutation (Glu(308)Lys) was detected in a 36-yr-old female patient. Compared with the wild-type receptor, cells expressing the mutated receptor showed a reduced stimulation of cAMP production and a reduction of radioactive alpha MSH binding. No segregation of the mutation with the obese phenotype could be demonstrated. A second, potentially pathogenic mutation (Ser(30)Phe) was detected in a 31-yr-old female patient. Functional analysis of the mutated receptor showed no change in the affinity to the natural ligand alpha MSH nor limited ability to stimulate cAMP production. Sixty lean subjects were also screened, and no additional variants of the MC4-R gene were observed, except for two individuals with the Val(103)Ile polymorphism. In conclusion, we have screened a population of Italian obese subjects for MC4-R variants, demonstrating a 1.7% prevalence of potentially pathogenic mutations. A novel heterozygous missense mutation (Glu(308)Lys) that impairs MC4-R functional activity in vitro was characterized.

Adolescent↗
PubMed2006

Bacterial contamination of keyboards: efficacy and functional impact of disinfectants.

BACKGROUND: Computers are ubiquitous in the healthcare setting and have been shown to be contaminated with potentially pathogenic microorganisms. This study was performed to determine the degree of microbial contamination, the efficacy of different disinfectants, and the cosmetic and functional effects of the disinfectants on the computer keyboards. METHODS: We assessed the effectiveness of 6 different disinfectants (1 each containing chlorine, alcohol, or phenol and 3 containing quaternary ammonium) against 3 test organisms (oxacillin-resistant Staphylococcus aureus [ORSA], Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus species) inoculated onto study computer keyboards. We also assessed the computer keyboards for functional and cosmetic damage after disinfectant use. RESULTS: Potential pathogens cultured from more than 50% of the computers included coagulase-negative staphylococci (100% of keyboards), diphtheroids (80%), Micrococcus species (72%), and Bacillus species (64%). Other pathogens cultured included ORSA (4% of keyboards), OSSA (4%), vancomycin-susceptible Enterococcus species (12%), and nonfermentative gram-negative rods (36%). All disinfectants, as well as the sterile water control, were effective at removing or inactivating more than 95% of the test bacteria. No functional or cosmetic damage to the computer keyboards was observed after 300 disinfection cycles. CONCLUSIONS: Our data suggest that microbial contamination of keyboards is prevalent and that keyboards may be successfully decontaminated with disinfectants. Keyboards should be disinfected daily or when visibly soiled or if they become contaminated with blood.

Aspergillus↗
PubMed1992

Optimum use of selective plated media in primary processing of respiratory tract specimens from patients with cystic fibrosis.

A total of 258 respiratory tract specimens from patients with cystic fibrosis were inoculated onto nine different plated media, and the rates of recovery of potential pathogens were compared. Media included sheep blood agar, enriched chocolate agar, MacConkey agar for gram-negative bacilli, chocolate agar containing bacitracin for Haemophilus spp., bromcresol green agar for yeasts, cetrimide agar for Pseudomonas spp., sheep blood agar containing colistin and nalidixic acid for gram-positive cocci, mannitol salt agar for Staphylococcus aureus, and oxidation-fermentation agar containing 300 U of polymyxin B per ml and 2 U of bacitracin per ml (OF-PBL medium) for Pseudomonas cepacia. With two exceptions, all of these media proved useful in recovering potential pathogens from respiratory tract specimens from patients with cystic fibrosis. The two exceptions were cetrimide agar and colistin-nalidixic acid-supplemented sheep blood agar, which were found to be superfluous. In addition, the results of this study further delineated the prevalence of selected bacteria and fungi in respiratory tract secretions from patients with cystic fibrosis. In rank order of frequency of isolation, we recovered isolates of Pseudomonas aeruginosa, Haemophilus parainfluenzae, Candida albicans, S. aureus, Haemophilus influenzae, molds, members of the family Enterobacteriaceae, yeasts other than Candida albicans, miscellaneous gram-negative bacilli, beta-hemolytic streptococci, P. cepacia, and Streptococcus pneumoniae.

Agar↗
PubMed2003

Exposure to bioaerosols in a municipal sewage treatment plant.

Microbiological air sampling was performed in a medium-size sewage treatment plant processing municipal wastewater from a city located in eastern Poland. Air samples for determination of the concentrations of viable mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, fungi and endotoxin were collected at 12 sites associated with various phases of sewage treatment process. The concentrations of total mesophilic bacteria (both Gram-positive and Gram-negative) were within a range of 2.4-70.7 x 10(2) cfu/m(3). Gram-positive coryneform bacteria and cocci were dominant, forming respectively 56.6 % and 24.0 % of the total count. The concentrations of Gram-negative bacteria, thermophilic actinomycetes, and fungi were respectively within ranges of 0.2-5.7 x 10(2) cfu/m(3), 0-0.5 x 10(2) cfu/m(3), and 0.24-1.4 x 10(2) cfu/m(3). Among Gram-negative bacteria, commonly occurred Enterobacter cloacae (17.3 % of the total count), followed by Acinetobacter calcoaceticus (16.2 %), Pseudomonas spp. (14.0 %) and Stenotrophomonas maltophilia (11.1 %). Among thermophilic actinomycetes prevailed Thermoactinomyces thalpophilus (47.2 %) and Thermoactinomyces vulgaris (22.2 %), while among fungi, Geotrichum candidum (32.2 %), Penicillium spp. (20 %), Cladosporium lignicola (12.2 %), and Alternaria alternata (10.4 %). Altogether, 20 potentially pathogenic species or genera of bacteria and fungi were identified in the air samples taken in the examined plant. The values of the respirable fraction of airborne microflora varied within a fairly wide range and were between 24.1-100 %. The concentrations of airborne endotoxin were in the range of 0.104-5.2 ng/m(3). In conclusion, the concentrations of microorganisms and endotoxin in the examined municipal sewage treatment plant were low and did not exceed proposed occupational exposure limit values. A moderate risk for the workers may be associated with the presence of potentially pathogenic microbial species having allergenic and/or immunotoxic properties.

Actinobacteria↗