Cometabolism of m-Chlorobenzoate by an Arthrobacter

Swabbing skin to collect bacteria for enumeration revealed that a single washing or rinsing of the swab in buffer removed between 90 and 95% of the bacteria collected. Further removal of the remaining bacteria from the initial swab by repeated washings of the swab produced plate counts that showed nearly proportional decreases in the numbers and types of bacteria retained or eluted from the swab. None of the commonly isolated cutaneous bacteria was retained or eluted from the single swab in numbers that misrepresented measurement of their proportions present in the sample. Populations of nonlipophilic bacteria on skin when present were mainly gram-positive catalase-producing cocci. Diphtheroids when present were chiefly lipophilic. Media containing furoxone were selective for cutaneous diphtheroids. The concentration of furoxone used affected isolation and enumeration of the diphtheroids. Lipophilic diphtheroids from the stratum corneum were basically aerobic and anaerobic incubation reduced or eliminated this group from enumeration studies. Lipophilic furoxone-resistant aerobic diphtheroids from several areas, particularly the nasal passages, occurred in numbers inversely proportional to the numbers of staphylococci for periods up to 11 months. The cocci-diphtheroid relationships occurred independently of the total number of aerobic bacteria present, the transient appearance of yeasts or gram-negative bacilli, the required use of certain antibiotics by the subjects, climate, age, and sex.     

Nitrogen Requirements and Uricolytic Activity of Cutaneous Bacteria

Uric acid, but not xanthine, was degraded by gram-positive catalase-producing cocci and diphtheroids which represented the two predominant human autochthonous skin bacteria. The proportions of uricolytic cocci and diphtheroids varied with the cutaneous site sampled. Uric acid and allantoin were not utilized by cocci or diphtheroids as sole sources of nitrogen. Uric acid appeared to act only as a secondary substrate for the gram-positive bacteria. Cutaneous cocci are known to be ureolytic but few diphtheroids had urease activity. Urea and ammonium nitrogen were not utilized as sole nitrogen sources by cocci, but some diphtheroids used these compounds for nitrogen. The majority of the cocci and diphtheroids were nutritionally fastidious and required amino-nitrogen for growth. In addition, some strains required vitamins and other unidentified metabolites found in yeast extract. These requirements were partially related to the cutaneous site from which the cocci or diphtheroids were isolated. Certain gram-negative bacilli degraded uric acid and utilized urate or its degradation products as nitrogen sources.     

Effect of antimicrobial soap containing chlorhexidine on the microbial flora of skin.

The qualitative and semiquantitative changes in the aerobic microbial flora of normal skin with the prolonged use of a chlorhexidine scrub (6 months) were investigated. More samples in the chlorhexidine scrub group had gram-negative bacilli in their axilla (63 of 96, 66%) and groin (36 of 96, 38%) than the controls (32 of 66, 49%, for axilla and 7 of 66, 11%, for groin; P = 0.01). Klebsiella and Enterobacter were the predominant organisms in the control and chlorhexidine groups, respectively. The chlorhexidine scrub produced a reduction in the total aerobic counts in the axilla, groin, and between the toes and the fingers. Fewer samples from the chlorhexidine-treated areas revealed the presence of lipophilic diphtheroids than did the controls. Lipophilic diphteroids were also reduced quantitatively in the groin and axilla with chlorhexidine treatment. No consistent pattern for the other major groups of bacteria was noted between the treatments.     

Preliminary studies of the effect of steroid hormones on skin bacteria in vitro

It results from studies on skin hormones that some of steroid hormones reach high concentrations on skin surface mainly during a course of acne vulgaris. Our studies indicate that the activity of hormones on skin bacteria can be multiform. Nineteen hormones of analytical grade of purity were tested. They were derived from different firms of synthesized in the Department of Endocrinology of the Pharmacology Institute of Polish Academy of Sciences in Cracow. Bacterial strains tested in this study were isolated from normal skin flora. The majority of the compounds tested in this study showed different reactivity toward Staphylococcus aureus as well as Staphylococcus epidermidis and anaerobic diphtheroids+ and sometimes aerobic ones.     

A comparison of contact plate and calcium alginate swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces

A contact plate method for enumeration of bacteriological contamination at 9 environmental sites in 64 homes was compared with swab sampling techniques. Contamination levels of 100 or more organisms/21-25 cm2 were demonstrated more frequently using swab methods, but for some sites where low numbers of organisms were present, higher recovery rates were obtained using contact plates. When contamination levels from contact plate and swab techniques were compared according to rank order a good correlation was obtained. Results of this investigation indicate that the contact plate method is satisfactory for differentiation of hygiene levels at environmental sites whilst facilitating handling of large numbers of samples in a field survey.     

A comparison of contact plate and calcium alginaie swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces

S cott , E. B loomfield , S.F. & B arlow , C.G. 1984. A comparison of contact plate and calcium alginate swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces. Journal of Applied Bacteriology 56 , 317–320.
A contact plate method for enumeration of bacteriological contamination at 9 environmental sites in 64 homes was compared with swab sampling techniques. Contamination levels of 100 or more organisms/21–25 cm² were demonstrated more frequently using swab methods, but for some sites where low numbers of organisms were present, higher recovery rates were obtained using contact plates. When contamination levels from contact plate and swab techniques were compared according to rank order a good correlation was obtained. Results of this investigation indicate that the contact plate method is satisfactory for differentiation of 'hygiene levels' at environmental sites whilst facilitating handling of large numbers of samples in a field survey.     

Quantitative assessment of vaginal microflora during use of tampons of various compositions

Although the effect of vaginal tampons on the microbial flora during menstruation has recently been studied by several investigators, quantitative effects attributable to particular tampon fibers have received less attention. The purposes of the present study were (i) to determine and then to compare the effects of polyacrylate rayon tampons and viscose rayon tampons on the normal vaginal flora, (ii) to compare quantitative bacterial counts obtained from these tampons with those obtained from concomitant vaginal swabs, and (iii) to determine whether either of these tampon types alters the vaginal microflora when compared with the microflora in the same women using all-cotton tampons or external catamenial pads. Tampon and swab samples were obtained at predetermined times from 18 women for an average of seven menstrual cycles. Samples consisting of swabs from women wearing menstrual pads were compared with swab and tampon samples taken at predetermined times during the menstrual cycle from women using cotton, polyacrylate rayon, or viscose rayon tampons. Samples were analyzed for total aerobic, facultative, and anaerobic bacterial counts. Statistical evaluation of the results indicated that, on the whole, total bacterial counts decreased during menstruation and that the numbers of bacteria in tampons tended to be lower than those in swab samples taken at the same time. The tampon type had little effect on the vaginal microflora.     

Numbers,diversity, and morphological characteristics of aerobic,chemoheterotrophic bacteria in deep subsurface sediments from a site in South Carolina

The aerobic, chemoheterotrophic bacteria indigenous to deep aquifers and other subsurface sediments (depths to 265 m) at a site in South Carolina were characterized by direct microscopy, enumeration of viable cells, analysis of colony morphologies on plates, and analysis of cell morphologies of isolated strains. Substantial numbers of viable bacteria (10^5‐10⁸/g) were present in all transmissive, aquifer sediments, and their numbers did not decrease with depth. Fewer bacteria (<10³/g) were detected in nontransmissive, confining layers. The highest viable counts were obtained on dilute media, but 10–50% of the bacteria in most aquifer sediments also grew rapidly on concentrated, nutrient‐rich media (indicating a high degree of metabolic flexibility). Most of the bacteria were mesophilic; relatively few psychrophiles or thermophiles were detected (<10³/g; in many cases, none). The bacterial flora was diverse (11–62 distinct colony types on enumeration plates of most aquifer sediments). Diversity did not decrease with depth, but the composition of the microflora (based on colony analysis) varied extensively from one geological formation to another. Almost 95% of the platable colonies that grew on enumeration plates contained nonstreptomycete bacteria, more than 80% of which were gram‐negative rods. Light microscopy of films released from aquifer sediments by flotation revealed the presence of dividing cells and microcolonies, thus implying that the in situ deep aquifer microflora was more metabolically active than that seen previously in shallow aquifers.     

A comparison of bacterial flora isolated by transtracheal aspiration and pharyngeal swabs in Macaca fascicularis.

The pulmonary flora of 30 monkeys (Macaca fascicularis) was sampled by the transtracheal aspiration technique and the pharyngeal swab method, and the results were compared. The transtracheal aspiration technique yielded lower numbers of bacteria in both aerobic and anaerobic cultures. The bacteria isolated by transtracheal aspiration were predominately pure culture, thereby lowering the possibility of contamination from commensal flora. Bordetella bronchiseptica was isolated from 23.3% of the monkeys by transtracheal aspiration, but this organism was not isolated when samples were collected with pharyngeal swabs.     

Aerobic microbial flora of intertrigenous skin.

The incidence and density of intertrigenous microflora were determined in subjects using nonmedicated soap. The axilla, groin, toe web, and finger web were examined. The incidence of gram-negative rods was 17% for the axilla, 13% for the groin, 10% for the toe web, and 9% for the finger web. Klebsiella, Proteus, and Enterobacter were the predominant organisms, in that order. The highest incidence of Staphylococcus aureus was in the groin (12%) and toe web (11%). Lipophilic diphtheroids were the most prevalent bacteria in the groin (1.1 X 10(6)/cm2) and toe web (1.2 X 10(6)/cm2). Nonlipophilic diphtheroids were the predominant flora in the axilla (1.3 X 10(7)/cm. Micrococci had the highest counts in the toe web (7.6 X 10(5)/cm2). The incidence of coagulase-negative staphylococci was highest in the finger web, but the major flora were those of micrococci.     

Quantitative assessment of vaginal microflora during use of tampons of various compositions.

Although the effect of vaginal tampons on the microbial flora during menstruation has recently been studied by several investigators, quantitative effects attributable to particular tampon fibers have received less attention. The purposes of the present study were (i) to determine and then to compare the effects of polyacrylate rayon tampons and viscose rayon tampons on the normal vaginal flora, (ii) to compare quantitative bacterial counts obtained from these tampons with those obtained from concomitant vaginal swabs, and (iii) to determine whether either of these tampon types alters the vaginal microflora when compared with the microflora in the same women using all-cotton tampons or external catamenial pads. Tampon and swab samples were obtained at predetermined times from 18 women for an average of seven menstrual cycles. Samples consisting of swabs from women wearing menstrual pads were compared with swab and tampon samples taken at predetermined times during the menstrual cycle from women using cotton, polyacrylate rayon, or viscose rayon tampons. Samples were analyzed for total aerobic, facultative, and anaerobic bacterial counts. Statistical evaluation of the results indicated that, on the whole, total bacterial counts decreased during menstruation and that the numbers of bacteria in tampons tended to be lower than those in swab samples taken at the same time. The tampon type had little effect on the vaginal microflora.     

Uneven distribution of aerobic mesophilic bacteria on human skin.

Viable aerobic mesophilic bacteria are not evenly distributed on the skin of the volar forearm. An increase in the size of the area sampled did not result in a proportional increase in the number of the viable aerobic mesophilic bacteria recovered.     

Uneven distribution of aerobic mesophilic bacteria on human skin.

Viable aerobic mesophilic bacteria are not evenly distributed on the skin of the volar forearm. An increase in the size of the area sampled did not result in a proportional increase in the number of the viable aerobic mesophilic bacteria recovered.     

Rapid enumeration of viable micro-organisms by staining and direct microscopy

A rapid method is described that uses the tetrazolium salt 2-( p -iodophenyl-3-( p -nitrophenyl)-5-phenyl tetrazolium chloride (INT) to stain viable micro-organisms retained on a filter membrane. Good correlation exists between numbers of INT stained cells and aerobic plate counts of single strain cultures of bacteria and yeasts. A pre-treatment step allows the technique to be used for pasteurized milk.     

The cutaneous microbiology of haired and hairless mice

H arnby , D., G owland , G., H olland , K.T. & K earney , J.N. 1990. The cutaneous microbiology of haired and hairless mice. Journal of Applied Bacteriology 69 , 686–691.
The cutaneous microflora of the mid-dorsal area of hairless and haired mice was studied by processing skin biopsies. In both C3H and CBA hairless genotype animals the prevalence of colonization and the bacterial density were significantly greater than in the haired animals. The dominant bacteria were staphylococci and aerobic coryneforms. No propionibacteria were isolated. Temporal studies with C3H mice showed that from 0 to 9 days after birth the cutaneous microflora reduced and from then on the haired genotype animals maintained a low cutaneous microflora, whilst hairless genotype animals gradually lost hair from head to tail and the microflora density increased. Reciprocal skin grafting between haired and hairless animals showed that the donor skin acquired the microflora characteristics of the recipient animal after 15 d post-grafting even though the donor skin remained morphologically true to genotype.     

Microbiology of Anaerobic Sludge Fermentation: I. Enumeration of the Nonmethanogenic Anaerobic Bacteria1

An anaerobic medium containing sludge supernatant fluid and glucose was used for enumeration of bacteria from the sludge fermentation. Comparison of viable counts from several separate samples consistently showed 10 to 100 times more anaerobic than aerobic bacteria. However, viable counts of the various samples differed by as much as 10 times; this variation probably reflects a change in the natural environment or sampling errors, or a combination of the two. Direct microscopic counts yielded values of about 10(10)/ml. The discrepancy between viable (10(8) to 10(9)/ml) and direct counts may be due to large numbers of dead cells. Random isolates of representative colonies from high dilutions exhibited the ability to ferment sugars and are not likely to be methane bacteria.     

Enumeration of viable anaerobic bacteria by solid phase cytometry under aerobic conditions

Classical enumeration methods for anaerobes are time-consuming and require special conditions. Solid phase cytometry (SPC) is a recent laser scanning technique for the quantitative detection of fluorescently labelled bacteria on a membrane filter that eliminates the need for a growth phase. Fluorescent labelling of cells results from the cleavage by intracellular esterases of a fluorescein type ester to yield a free fluorescein derivative, which is retained only in cells with an intact cytoplasmic membrane. However, as the standard labelling procedure is carried out under the conditions of aerobiosis, labelling of anaerobic bacteria does not appear to be obvious. We have labelled eight strains of vegetative anaerobic bacteria (i.e. Bacteroides thetaiotaomicron, Clostridium bifermentans, C. butyricum, C. perfringens, Fusobacterium nucleatum, Porphyromonas canoris, P. gingivalis, Propionibacterium acnes) and two strains of spores (C. butyricum, C. perfringens,) within 4 h under aerobic conditions. However, anaerobiosis remained necessary for spores of C. sordellii, C. sporogenes, C. tyrobutyricum. For vegetative cells of all strains, plots of SPC versus plate counts were linear with slopes exceeding 1.0, indicating that SPC consistently yielded higher numbers of bacteria.     

A Simplified Overlay Plaque Technic for Evaluating Responses of Small Free-Living Amebae in Grassland Soils*

SYNOPSIS. The responses of amebae and bacteria in a grassland soil were investigated by an overlay plaque technic developed in this laboratory. This procedure, using Aerobacter aerogenes as the food source, allowed convenient assay of significant changes in ameba populations which resulted from additions of nutrient and water. In comparison with controls, when water was added an initial increase occurred in bacterial counts followed by an increase in the numbers of amebae. Upon addition of glucose, ameba populations increased initially and then decreased with time, while populations of bacteria remained constant. The addition of hay resulted in significant increases in populations of bacteria and amebae. Plaque appearance on enumeration plates was most rapid with inocula from nutrient-treated soils. Predominant amebae recovered by this technic were species of Acanthamoeba and Hartmannella. They were estimated to be present in untreated soils at 3.2 × 10³/gram. Ameba feeding experiments were used to evaluate the possible suitability of other bacteria as food. The results indicated that nonpigmented laboratory strains of bacteria were preferred, while pigmented grassland isolates were more rapidly utilized. Small soil amebae appear to be sensitive to minor soil perturbations, and the enumeration procedure developed in this study should aid in following their responses to environmental stresses.     

Comparison of two techniques for obtaining endometrial bacteriologic cultures in the mare

The endometria of 39 mares were cultured simultaneously using a swab guarded with a double cannula and distal, teflon plug and an unguarded swab with a single, open cannula. Sheep blood (5%) agar, Mac-Conkey's agar, and Sabourad's agar media were innoculated with each swab. The presence of bacterial or fungal growth was determined after 24 and 48 hours of aerobic incubation at 37 C. There were significantly more plates that failed to yield bacterial or fungal growth when streaked with swab specimens obtained with the guarded cannula than when streaked with those obtained with the unguarded cannula. It was concluded that while culturing the endometrium of mares for bacteria or fungi, the use of a guarded instrument consisting of a double cannula with a closed end will result in the recovery of fewer contaminants; therefore, it will be more likely to result in a more accurate representation of uterine bacterial and fungal flora.     

Effects of a Systemic Antibiotic on Nasal Bacterial Ecology in Man

The nasal flora of coagulase-positive staphylococcus carriers and noncarriers was studied in aerobic conditions in 17 individuals. Five hundred milligrams of cephalexin was given orally four times daily for 12 days, and its effects on the nasal bacteria were determined quantitatively before, during, and after treatment. The total count obtained before the drug treatment was 5.4 x 10(6) in carriers and 3.9 x 10(6) in noncarriers. The lowest total count observed was 3 days after the cessation of the drug. The increase in gram-negative rods was seen 9 days after antibiotic therapy, not during the greatest reduction of gram-positive bacteria. Coagulase-positive cocci and diphtheroids were most sensitive to drug treatment. After 36 days, the total count was restored to pretreatment level. Diphtheroids did not return to the original number and were replaced by a corresponding increase of resistant coagulase-negative cocci. An inverse relationship between coagulase-negative cocci and lipophilic diphtheroids was seen in the anterior nares of many individuals. No gross difference in nasal ecology to differentiate carriers from noncarriers was seen.