Microbiology of infected pustular psoriasis lesions

BACKGROUND: Bacterial infections can occur in lesions of pustular psoriasis (PP). The objective of this study was to establish the aerobic and anaerobic microbiology of secondarily infected PP. METHODS: A retrospective 10-year review was carried out of clinical and microbiology laboratory records from patients with secondarily infected PP lesions, whose specimens of infected sites were processed for the presence of aerobic and anaerobic bacteria. RESULTS: Bacterial growth was noted in 23 specimens. Aerobic or facultative anaerobic bacteria only were present in 12 patients (52%), anaerobic bacteria only in four (17%), and mixed anaerobic-aerobic flora was present in seven (30%). Thirty-six isolates were recovered (1.6 per specimen), 23 aerobic or facultative bacteria and 13 strict anaerobes. The predominant aerobic and facultative bacteria were Staphylococcus aureus (15 isolates), Group D Enterococcus (two isolates), and Escherichia coli (two isolates). The predominant anaerobes were Peptostreptococcus spp. (six isolates) and Bacteroides fragilis group, Propionibacterium acnes, and pigmented Prevotella spp. in two each. Single bacterial isolates were recovered in 14 patients (61%), 11 of which were S. aureus. Nineteen of the organisms isolated from 18 patients (78%) produced the enzyme beta-lactamase. S. aureus was isolated from all body sites. Organisms that resided in the mucous membranes close to the lesions predominated in these infections. Enteric Gram-negative rods and Bacteroides fragilis group predominated in lesions on the legs and buttocks. Group A beta-hemolytic streptococci, pigmented Prevotella, and Fusobacterium spp. were most frequently recovered in lesions of the hand. CONCLUSIONS: The polymicrobial etiology of secondarily infected PP lesions and the association of bacterial flora with the anatomic site of the lesions were demonstrated.     

MICROBIOLOGY OF INFECTED ATOPIC DERMATITIS

Background. Bacterial infections occur frequently in lesions of atopic dermatitis (AD). The objectives of the study were to establish the aerobic and anaerobic microbiology of secondarily infected AD. Methods. A retrospective review was carried out of clinical and microbiology laboratory records and of data obtained from patients with secondarily infected AD lesions, whose specimens of infected sites were processed for the presence of aerobic and anaerobic bacteria. Results. Bacterial growth was noted in 41 specimens. Aerobic or facultative anaerobic bacteria only were present in 15 patients (36%), anaerobic bacteria only in eight (20%), and mixed anaerobic-aerobic flora was present in 18 (44%). Seventy- two isolates were recovered (1.8 per specimen), 34 aerobic or facultative bacteria, 35 strict anaerobes, and three Candida sp. The predominant aerobic and facultative bacteria were Staphylococcus aureus (12 isolates). Group A beta hemolytic streptococcus in five isolates, and Escherichia coli in four. The predominant anaerobes were peptostreptococcus spp. (13 isolates), pigmented Prevotella and Porphyromonas spp. in eight, and Fusobacterium spp. in four isolates. Single bacterial isolates were recovered in 14 patients (34%), seven of which were S. aureus. Twenty-one of the organisms isolated from 16 patients (39%) produced the enzyme beta-lactamase. Organisms that resided in the mucous membranes close to the lesions predominated in these infections. Enteric gram-negative rods and bacteroides fragilis group predominated in lesions on legs and buttocks. Group A beta-hemolytic streptococci, pigmented Prevotella, and Porphyromonas and Fusobacterium spp. were most frequently recovered in lesions of the finger, scalp, face, and neck. Conclusions. The polymicrobial etiology of secondarily infected AD lesions and the association of bacterial flora with the anatomic site of the lesions are demonstrated.     

Microbiology of Nonbullous Impetigo

Abstract: Our objective was to establish the aerobic and anaerobic microbiology of nonbullous impetigo (Nl) in children. We used a retrospective review of clinical microbiology laboratory and patients'records. Specimens were obtained from 40 patients with Nl lesions and showed bacteriai growth. Aerobic or facultative anaerobic bacteria only were present in 24 patients (60%), strict anaerobic bacteria only in 5 patients (12.5%), and mixed anaerobic-aerobic flora was present in 11 patients (27.5%). Sixty-four isolates were recovered (1.6 per specimen): 43 aerobic or facultative, and 21 anaerobic. The predominant aerobic and facultative bacteria were Staphylococcus aureus (29 isolates). Group A beta hemolytic streptococcus (GABHS) (13 Isolates), and Escherichia coli (1 isolate). The predominant anaerobes were Peptostreptococcus spp. (12), pigmented Prevotella spp. (5), Fusobacterium spp. (2), and Bacteroides fragilis (1). Single bacterial isolates were recovered in 17 patients (42.5%), 13 of which were S. aureus. S. aureus alone or mixed with GABHS or Peptostreptococcus spp. were isolated from all body sites. Mixed flora of Peptostreptococcus spp. with Prevotella spp. or Fusobacterium spp. was mostly found in infections of the head and neck, while E. coli mixed with B. fragills and Peptostreptococcus spp. were isolated from one infection of the buttocks area. Thirty-three organisms isolated from 32 patients (80%) produced the enzyme beta-lactamase. This study demonstrates the polymicrobial aerobic-anaerobic microbiology of Nl lesions.     

Microbiology of infected hemangiomas in children

Bacterial infections are a common complication of hemangiomas in children. The objective of this study was to establish the aerobic and anaerobic microbiology of infected hemangiomas. A retrospective 8-year review of clinical and microbiology laboratory records from patients with secondarily infected hemangiomas was carried out. Specimens from infected sites were processed for the presence of aerobic and anaerobic bacteria. Bacterial growth was present in 32 of 38 specimens. Aerobic bacteria alone were recovered in 12 infected hemangiomas (37.5%), anaerobic bacteria alone in 8 (33%), and mixed aerobic and anaerobic flora in 12 (37.5%). A total of 80 isolates (47 aerobes and 33 anaerobes) were recovered, giving an average of 2.5 isolates per specimen (1.5 aerobes and 1.0 anaerobes). The highest number of isolates were recovered in infections of the perineum (3.7 per site) and the legs (2.8 per site). The predominant aerobic isolates were Staphylococcus aureus, group A beta-hemolytic streptococci, and Enterobacteriaceae. The predominant anaerobes were Peptostreptococcus sp., gram-negative bacilli, and Fusobacterium sp. Organisms that belong to the mucous membranes close to the lesions predominated in infections next to those membranes. The polymicrobial etiology of secondarily infected hemangiomas and the association of bacterial flora with the anatomic site of the lesions is thereby demonstrated.     

MICROBIOLOGY OF SECONDARILY INFECTED DIAPER DERMATITIS

Specimens obtained from 67 infants with secondarily infected diaper dermatitis were cultured for aerobic and anaerobic bacteria. Bacteria growth was obtained in 58. Aerobic facultative bacteria or Candida sp. only were present in 28 patients (48%), anaerobic bacteria only in 11 (19%), and mixed anaerobic with aerobic, facultative, or yeast flora was present in 19 (33%). Ninety-one bacterial or fungal isolates were recovered (1.6 per specimen), 54 (0.9 per specimen) aerobic or facultative bacteria, 8 (0.1 per specimen) Candida sp., and 31 (0.6 per specimen) strict anaerobes. The predominant aerobic and facultative bacteria were Staphylococcus aureus (23 isolates), Streptococcus sp. (16), and Escherichia coli (6). The predominant anaerobes included Bacteroides sp. (12, including 9 Bacteroides fragilis group) and Peptostreptococcus sp. (11). Single bacterial isolates were recovered in 32 (55%) patients, 18 of which were S. aureus. Twenty-five beta-lactamase-producing bacteria were detected in 22 (51%) of the 43 tested patients. These included 16 S. aureus and 6 B. fragilis group. These data highlight the importance of anaerobic bacteria in the polymicrobial nature of secondarily infected diaper dermatitis.     

Aerobic and anaerobic microbiology of chronic venous ulcers

Abstract
Background The role of bacteria in the pathogenesis of chronic venous leg ulcers (CVLU) is unclear. The objective of the study was to establish the aerobic and anaerobic bacteriology of CVLU.
Methods A retrospective review was carried out of the clinical and microbiological laboratory records obtained from patients with CVLU. Microorganisms were grown from 43 specimens obtained from 41 patients.
Results Aerobic or facultative bacteria alone were present in 18 (42%) specimens, anaerobic bacteria only in three (7%), and mixed aerobic–anaerobic flora in 22 (51%).
In total, there were 97 isolates, 64 aerobic or facultative and 33 anaerobic, an average of 2.3 isolates per specimen (1.5 aerobes and 0.8 anaerobes). The predominant aerobic organisms were Staphylococcus aureus (26 isolates), group D streptococci (5), and Escherichia coli (5). The predominant anaerobes were Peptostreptococcus spp. (15), Bacteroides fragilis group (6), Propionibacterium acnes (4), and Prevotella spp. (3).
Conclusions CVLU have a polymicrobial aerobic–anaerobic flora.     

Microbiology of infected epidermal cysts

Specimens from 231 epidermal cyst abscesses were inoculated on media supportive for growth of aerobic and anaerobic bacteria. Of these, 192 yielded bacterial growth. Aerobic or facultative bacteria only were recovered in 84 specimens (44%), anaerobic bacteria only in 57 specimens (30%), and mixed aerobic and anaerobic bacteria in 51 specimens (26%). A total of 315 isolates (162 anaerobes and 153 aerobes) were recovered. An average of 0.8 aerobic or facultative isolates per infected cyst were recovered, and this number was unrelated to the cysts' anatomic sites. However, the number of anaerobic bacteria varied; they were isolated more frequently in perirectal (1.5 isolates per specimen), vulvovaginal (1.4), and head (1.1) infections, and less frequently in trunk (0.7) and extremities (0.4) infections. The predominant aerobic or facultative bacteria were Staphylococcus aureus (81 isolates), group A streptococcus (9 isolates), and Escherichia coli (7 isolates). The predominant anaerobic organisms were Peptostreptococcus species (85 isolates) and Bacteroides species (55 isolates, including 12 Bacteroides melaninogenicus and 9 Bacteroides fragilis groups). The study highlights the polymicrobial nature and predominance of anaerobes in cyst abscesses in the perirectal, vulvovaginal, and head areas.     

The microbiology of infected and noninfected leg ulcers

BACKGROUND: A clinical study was undertaken to investigate and compare specifically the aerobic and anaerobic microbiology of infected and noninfected leg ulcers. METHODS: Leg ulcers, defined as being infected on the basis of clinical signs, were swab sampled and investigated for aerobic and anaerobic microorganisms using stringent isolation and identification techniques. RESULTS: Two hundred and twenty isolates were cultured from 44 infected leg ulcers, in comparison with 110 isolates from 30 noninfected leg ulcers. Statistical analysis indicated a significantly greater mean number of anaerobic bacteria per infected ulcer (particularly Peptostreptococcus spp. and Prevotella spp.) in comparison with the noninfected ulcer group (2.5 vs. 1.3, respectively) (P < 0.05). Also, anaerobes represented 49% of the total microbial composition in infected leg ulcers compared with 36% in noninfected leg ulcers. The mean numbers of aerobes per wound in the two ulcer groups were not statistically different (P > 0.05). The study failed to demonstrate a clear correlation between commonly implicated facultative pathogens and wound infection. The isolation rate of Pseudomonas aeruginosa was generally low and, although Staphylococcus aureus was a frequent isolate in both wound types, it was more prevalent in noninfected leg ulcers. CONCLUSIONS: This study has demonstrated the complex aerobic-anaerobic microflora which exists in leg ulcers, the prevalence of anaerobes in infected wounds, and a poor correlation between the presence of specific aerobic pathogens and wound infection. In view of these findings, the role of microbial synergistic interactions in the pathogenesis of chronic wound infection may be of greater clinical importance than the isolated involvement of any specific potential pathogen.     

Aerobic and Anaerobic Microbiology of Necrotizing Fasciitis in Children

Abstract: Specimens obtained from eight children with necrotizing fasciitis (NF) were cultured for aerobic and anaerobic bacteria. A total of 21 isolates were recovered, 13 anaerobic and 8 aerobic or facultatives. The facultative organism Streptococcus pyogenes was present alone in two (25%) instances, and mixed aerobic and anaerobic bacteria were isolated in six (75%). The predominant isolates were Peptostreptococcus spp. (6 isolates, including 3 Peptostreptococcus magnus ). S. pyogenes (4), Bacteroides fragilis group (3), Clostridium perfringens (2), Escherichia coli (2), and Prevotella spp. (2). Organisms similar to the ones isolated from the NF aspirates were recovered in the blood of all patients except one. These included S. pyogenes (3 isolates). B. fragilis group (2), E. coli (1), and P. magnus (1) and Clostridium perfringens (1). All patients underwent surgical fasciotomy, and four required skin grafting. Antimicrobials were administered to all children. Despite extensive resection and intense supportive therapy, three patients died from sepsis accompanied by shock acidosis and disseminated intravascular coagulation. These findings illustrate the polymicrobial aerobic-anaerobic flora of NF in children.     

Microbiology of perianal cellulitis in children: comparison of skin swabs and needle aspiration

Objective To establish the aerobic and anaerobic microbiology of perianal cellulitis in children, comparing skin swab and needle aspirate methodology. Method Swabs of involved skin and needle aspirates of cellulitis were studied for aerobic and anaerobic bacteria. Results Specimens obtained from 10 patients with perianal cellulitis showed bacterial growth. Polymicrobial aerobic–anaerobic flora was found in all skin surface cultures, where the predominate isolates were Peptostreptococcus spp., Escherichia coli, and alpha hemolytic streptococci. The number of isolates in needle aspirates varied between one and two. The predominant ones were E.coli (3), Peptostreptococcus spp. (3), Staphylococcus aureus (2), and Bacteroides fragilis group (2). Complete or partial concordance in microbiology between skin swabs and needle aspirates was present in six instances. In four instances, isolates recovered from needle aspirates were not isolated from the skin surface. Conclusions This study demonstrates the diversity of aerobic and anaerobic organisms isolated from perianal cellulitis, and the superiority of needle aspirates in establishing the microbiology of the infection.     

Bacteriological study of epidermal cysts

The aim of this study was to determine whether bacterial infection plays a significant role in the inflammatory process of epidermal cysts. Samples from 152 patients (115 cases of inflamed and 37 of uninflamed epidermal cysts) were subjected to aerobic and anaerobic bacterial culture and the isolates were investigated. The rate of bacterial growth and the recovered anaerobes were significantly greater in the inflamed than the uninflamed epidermal cysts. However, it is difficult to determine whether recovered isolates from epidermal cysts represent "infection" or "colonization". In conclusion, this study revealed the predominance of anaerobes in inflamed cysts, strongly suggesting that anaerobes play a role in the inflammatory process.     

Anaerobic flora in trophic ulcers in leprosy patients

Material from 108 trophic ulcers from leprosy cases were studied bacteriologically. 4 cases showed growth of pure anaerobes and 69 showed mixed growth of aerobic and anaerobic bacteria. The predominant anaerobes were Fusobacteria (41), anaerobic cocci (30) and Bacteroides (25). Clostridia were isolated only in 10 cases. Metronidazole, chloramphenicol, penicillin and ampicillin were found effective against anaerobes in in-vitro studies.     

Anaerobes in genitourinary infections in men.

Urethral and sub-preputial swabs from 150 men were examined. There was a strong association between the isolation of anaerobic bacteria, particularly Bacteroides spp, and a clinical diagnosis of balanoposthitis, non-specific urethritis (NSU), or both. Aerobic bacteria formed the predominant flora in 28 healthy controls whereas anaerobes were predominant in specimens from 79 patients with balanoposthitis, from 24 with NSU, and from 19 with both. Bacteroides spp were the commonest isolates in all patient groups; B asaccharolyticus, B melaninogenicus ss intermedius, B ureolyticus, and B bivius were the most common species. The results obtained with the two swabs were identical except that Gardnerella vaginalis was isolated from the urethral swab only in five patients.     

Bacteriology of hidradenitis suppurativa exacerbations and deep tissue cultures obtained during carbon dioxide laser treatment

Summary Background Previous studies have shown different bacteria in hidradenitis suppurativa (HS) lesions, but the literature regarding bacteria in acute exacerbation of HS is sparse. Objectives To determine the type of bacteria isolated from HS lesions during exacerbations of the disease. Methods Patients with HS with acute nodules or abscesses were examined and treated by carbon dioxide laser vaporization. Bacterial samples for aerobic and anaerobic cultures were taken from the skin surface (before surgery) and then from the deeper layers (during surgery) of the lesions. At each level two samples were taken, one with a punch biopsy and one by pressing a soft agar gel against the skin. The bacterial findings were typed and quantified. Results A total of 10 patients (eight women and two men), with a mean age of 37·2 years and a mean HS duration of 14·5 years, were included. All of them had an ongoing exacerbation (mean duration 5·6 days) of their HS, with one inflamed lesion that was treated by carbon dioxide laser vaporization. Coagulase‐negative staphylococci (CNS) were found in the deep layers in all 10 patients. Nine of the patients carried Corynebacterium spp. and two alpha‐haemolytic streptococci at various levels. Among the anaerobic microorganisms, Gram‐positive cocci were the most common bacteria. Conclusions As found in a previous study, CNS were the most common bacteria, but contrary to what we expected, Staphylococcus aureus was not found in any cultures from acute inflammatory nodules of HS exacerbations.     

THE EFFECT OF BACTERIAL COLONIZATION ON VENOUS ULCER HEALING

To determine the effect of bacterial colonization on venous ulcer healing, 82 patients with 100 venous ulcerated limbs were each studied prospectively for six months. Despite bacteriological swab results, topical or systemic antibiotics were not administered unless cellulitis supervened. Initial ulcer size, length of ulcer history and time to complete healing of colonized and uncolonized ulcers were determined and compared. Organisms were cultured from 83 limbs prior to commencement of treatment, the commonest isolates being Staphylococcus aureaus (48%), mixed coliforms (28%), Pseudomonas aeruginosa (21%) and anaerobes (17%). When compared with ulcers with no bacterial growth, colonized ulcers were of longer duration (p [symbol: see text] 0.01), had a larger initial size (p [symbol: see text] 0.001) and had significantly longer healing time (p [symbol: see text] 0.001). When analysed individually beta-haemolytic streptococci, anaerobes, Staphylococcus aureus and coliforms were associated with delayed healing. Delayed healing was not found with Pseudomonas aeruginosa, although pseudomonas-colonized ulcers were significantly larger and of longer duration than uncolonized ulcers. Bacterial colonization is associated with delayed venous ulcer healing. To further clarify the pathogenicity of colonizing bacteria, however, the effect of their eradiction on healing of venous ulcers needs to be established.     

Correlations between epithelial cells and bacterial populations in bacteriological skin samples

The purposes of this study were to determine whether the variability in populations of skin bacteria observed between individuals is related to the number of epithelial cells removed during the skin scrubbing procedure and also whether any particular group of microorganisms can be directly associated with epithelial cells. Foreheads of 31 subjects were sampled using the cup scrubbing method, and bacterial populations were quantified as: total anaerobes, aerobes, Propionibacterium spp., aerobic coryneforms, and Micrococcaceae. Epithelial cells were counted in a haemocytometer. Correlation coefficients were positive between total bacterial populations and epithelial cell counts, with the largest values of 0.64 for Propionibacterium spp., 0.58 for Micrococcaceae, and 0.15 for aerobic coryneforms. High epithelial cell counts were always associated with high bacterial populations, but high bacterial counts occurred, in some instances, with low epithehal cell counts; epithelial cells are not, therefore, responsible for variations in bacterial populations in all cases. Stained smears of epithelial cells from subjects from whom aerobic coryneforms were not cultured showed microcolonies of presumptive anaerobic diphtheroids, closely associated with epithelial cells. These findings and the high correlation between Propionibacterium spp. and epithelial cells suggests a re-examination of the location of anaerobes in the stratum corneum.     

Isolation and identification of anaerobic organisms from the male and female urogenital tracts

Since Bacteroides spp may play an important role together with Gardnerella vaginalis in the pathogenesis of non-specific vaginitis and balanoposthitis, anaerobic organisms were isolated and identified from 34 female and 20 male patients attending a department of genitourinary medicine, and the results compared with the clinical findings and the presence of other routinely isolated pathogens. Twenty-three different organisms were recovered from 13 of the 20 men; of these organisms, 20 were of the Bacteroides spp. Most isolates were of the B melaninogenicus/oralis group, which forms part of the commensal vaginal flora in women. A definite association between the presence of anaerobes and other pathogens needs to be firmly established, as this obviously causes important complications in treating these conditions.     

Isolation and identification of anaerobic organisms from the male and female urogenital tracts.

Since Bacteroides spp may play an important role together with Gardnerella vaginalis in the pathogenesis of non-specific vaginitis and balanoposthitis, anaerobic organisms were isolated and identified from 34 female and 20 male patients attending a department of genitourinary medicine, and the results compared with the clinical findings and the presence of other routinely isolated pathogens. Twenty-three different organisms were recovered from 13 of the 20 men; of these organisms, 20 were of the Bacteroides spp. Most isolates were of the B melaninogenicus/oralis group, which forms part of the commensal vaginal flora in women. A definite association between the presence of anaerobes and other pathogens needs to be firmly established, as this obviously causes important complications in treating these conditions.     

Bacteriological examination of inflamed epidermal cysts: a survey between 2008 and 2009 at a hospital in southern Taiwan

BackgroundInflamed epidermal cysts are common clinical conditions, and they frequently form abscesses. We designed a study to delineate the bacteriology of inflamed epidermal cysts.MethodsWe enrolled 61 adult patients with inflamed epidermal cysts characterized by surface erythema, with or without tenderness, or localized abscess formation within the cyst cavity. Incision and drainage of the cysts were performed, and the contents were sent for aerobic and anaerobic bacterial culture. The locations of the cyst and culture results were recorded for statistical analysis.ResultsA total of 61 cysts and 122 cultures were obtained. The most common locations of the inflamed cysts were the face, neck, and scalp (34.4%), followed by the trunk (32.8%), then the buttocks, inguinal areas, perineum, and axillae (16.4%), and the extremities (16.4%). The culture results were positive in 88.5% of patients, and anaerobes were more frequently isolated than were aerobes. Pure aerobes represented 31.1% of the cultures; pure anaerobes, 36.1%, and combined aerobes and anaerobes, 21.3% (n = 13). The most common anaerobic organisms found were Propionibacterium spp (40.8%), followed by Peptostreptococcus spp (36.7%), Staphylococcus saccharolyticus (14.4%), Prevotella (4.1%), Bacteroides fragilis (2.0%), and Fusobacterium spp (2.0%). The most commonly isolated aerobes were Staphylococcus spp (40%), followed by Enterobacter spp (11.3%), Proteus mirabilis (8.5%), Citrobacter diversus (8.5%), Klebsiella pneumoniae (5.7%), Corynebacterium (5.7%), Morganella morganii (2.9%), Enterococcus faecalis (2.9%), group A β-hemolytic streptococcus (2.9%), Pseudomonas aeruginosa (2.9%), and Providencia rettgeri (2.9%).ConclusionsBoth aerobic and anaerobic microorganisms were present in the inflamed epidermal cysts, although the anaerobic bacteria, specifically, Propionibacterium spp and Peptostreptococcus spp, were isolated slightly more frequently. Antibiotics directed against anaerobes may be considered in the treatment regimen for inflamed epidermal cysts.     

The infectious aetiology of tropical ulcer—a study of the role of anaerobic bacteria

We have cultured anaerobic bacteria from patients with tropical ulcers. Fusobacteria were isolated most frequently. Anaerobes were always present, together with aerobes or facultative anaerobes, particularly in early phase ulcers, suggesting that the combination of organisms is important in the pathogenesis of the disease. Spirochaetes were identified in material examined by light and electron microscopy, but were not cultured.