Mental illness in adults with fetal alcohol syndrome or fetal alcohol effects

PURPOSE: To investigate the aerobic and anaerobic microbiology of dacryocystitis. METHOD: Retrospective review of the 62 clinical and microbiologic records collected between 1980 and 1990. RESULTS: Aerobic or facultative bacteria were recovered in 32 cases (52%), anaerobic bacteria only in 20 cases (32%), mixed aerobic and anaerobic bacteria in seven cases (11%), and fungi in three cases (5%). A total of 94 organisms (1.5 per specimen), which included 56 aerobic or facultative anaerobic organisms, 35 anaerobic organisms, and three fungi, were recovered. The predominant aerobic and facultative bacteria were Staphylococcus aureus (15 isolates), Staphylococcus epidermidis (13 isolates), and Pseudomonas species (seven isolates). The most frequently recovered anaerobes were Peptostreptococcus species (13 isolates), Propionibacterium species (12 isolates), Prevotella species (four isolates), and Fusobacterium species (three isolates). The predominant fungus was Candida albicans (two isolates). Polymicrobial infection was present in 28 cases (45%). CONCLUSION: These data highlight the potential importance of anaerobic bacteria in dacryocystitis.     

Synthesis of novel cyclic protease inhibitors using Grubbs olefin metathesis

The microbiologic features of infected sinus aspirates in nine children with neurologic impairment were studied. Anaerobic bacteria, always mixed with aerobic and facultative bacteria, were isolated in 6 (67%) aspirates and aerobic bacteria only in 3 (33%). There were 24 bacterial isolates, 12 aerobic or facultative and 12 anaerobic. The predominant aerobic isolates were Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus (2 each) and Proteus mirabilis, Pseudomonas aeruginosa, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae (1 each). The predominant anaerobes were Prevotella sp. (5), Peptostreptococcus sp. (4), Fusobacterium nucleatum (2), and Bacteroides fragilis (1). Beta-lactamase-producing bacteria were isolated from 8 (89%) patients. Organisms similar to those recovered from the sinuses were also isolated from tracheostomy site and gastrostomy wound aspirates in five of seven instances. This study demonstrates the uniqueness of the microbiologic features of sinusitis in neurologically impaired children, in which, in addition to the organisms known to cause infection in children without neurologic impairment, facultative and anaerobic gram-negative organisms that can colonize other body sites are predominant.     

Aerobic and anaerobic bacteriology of cutaneous abscesses in children

Specimens from 209 cutaneous abscesses in children were cultured for aerobic and anaerobic microorganisms. Of these, nine (4%) were sterile and 51 (24%) yielded pure cultures that were predominantly Staphylococcus aureus. The rest of the abscesses yielded growth of two or more aerobic and/or anaerobic organisms. The data were organized according to these anatomic locations: head, neck, trunk, finger, nailbed, hand, leg, buttocks, perirectal, and vulvovaginal areas. Aerobic bacteria only were present in 92 specimens (46%), anaerobes only were isolated in 52 (26%), and mixed aerobic and anaerobic bacteria were present in 56 abscesses (28%). A total of 467 isolates (270 anaerobes and 197 aerobes) were recovered, accounting for 2.3 isolates per specimen (1.3 anaerobes and 1.0 aerobes). The presence of more than one anaerobe per abscess was obtained from the vulvo-vaginal, buttocks, perirectal, finger, nailbed, and head areas. Aerobes were more prevalent in the neck, hand, leg, and trunk areas. The predominant aerobes recovered were: S aureus (89 isolates), alpha- and nonhemolytic streptococci (29), group A beta-hemolytic streptococci (16), Enterobacter (10), and Escherichia coli (8). The predominant anaerobes recovered were anaerobic Gram-positive cocci (79 isolates), Bacteroides sp (116, including 31 B melaninogenicus group and 29 B fragilis group), and Fusobacterium sp (39). Our findings indicate the polymicrobial nature and predominance of anaerobes in cutaneous abscesses in children in perirectal, head, finger, and nailbed areas.     

Penicillium marneffei fungemia in an AIDS patient: the first case report in Taiwan

The microbiology of in 55 ear aspirates obtained from 34 children with chronic otorrhea was studied. Aspiration of the middle ear exudate was done immediately following removal of tympanostomy tube (TT). The middle ear aspirates and swab specimens of the external auditory canals were cultured for aerobic and anaerobic bacteria. Sixty-five isolates were recovered only from the middle ears, 73 only from the external ear canals, and 73 were present at both sites. Analysis of the 138 middle ear isolates demonstrated the recovery of aerobic bacteria only in 28 patients (50%), anaerobes only in seven (13%), and both aerobes and anaerobes in 20 (36%). There were 77 aerobic and 61 anaerobic isolates. Commonly recovered aerobes were Pseudomonas aeruginosa (17 isolates), Staphylococcus aureus (11), Proteus sp. (7), Moraxella catarrhalis (6), Klebsiella pneumoniae (5) and non-typable Haemophilus influenzae (5). Commonly isolated anaerobes were Peptostreptococcus sp. (25 isolates), Prevotella sp. (10), Bacteroides sp. (8) and Fusobacterium sp. (6). Pseudomonas aeruginosa and S. aureus were more often isolated in children older then 6 years. These findings demonstrate the polymicrobial bacteriology of TT-related otorrhea in children. Specimens collected from the external auditory canals can be misleading. Reliable information can be obtained from the ear exudes when collected through the TT or through the open perforation after their removal.     

Aerobic and anaerobic microbiology of surgical-site infection following spinal fusion

The aerobic and anaerobic microbiology of surgical-site infections (SSI) following spinal fusion was retrospectively studied. This was done by reviewing the clinical and microbiological records at the Naval Hospital in Bethesda, Md., from 1980 to 1992. Aspirates of pus from 25 infection sites showed bacterial growth. Aerobic bacteria only were recovered from 9 (36%) specimens, anaerobic bacteria only were recovered from 4 (16%), and mixed aerobic and anaerobic bacteria were recovered from 12 (48%). Sixty isolates were recovered: 38 aerobes (1.5 isolates per specimen) and 22 anaerobes (0.9 isolate per specimen). The predominant aerobes were Escherichia coli (n = 8) and Proteus sp. (n = 7). The predominant anaerobes were Bacteroides fragilis group (n = 9) and Peptostreptococcus sp. (n = 6) isolates. An increase in recovery of E. coli and B. fragilis was noted in patients with bowel or bladder incontinence. This study highlights the polymicrobial nature of SSI and the importance of anaerobic bacteria in SSI following spinal fusion.     

Aerobic and anaerobic microbiology of axillary hidradenitis suppurativa

A retrospective review of the microbiological and clinical data of 17 specimens obtained from axillary hidradenitis suppurativa (HS) over a period of 6 years was undertaken to study the aerobic and anaerobic microbiology of this condition. A total of 42 bacterial isolates (2.5 per specimen) were obtained, 12 aerobic or facultative (0.7 per specimen) and 30 anaerobic or micro-aerophilic (1.8 per specimen). Aerobic and facultative bacteria only were isolated in six (35%) cases, anaerobic bacteria only in seven (41%) and mixed aerobic and anaerobic bacteria in four (24%). The predominant aerobic bacteria were Staphylococcus aureus (six isolates), Streptococcus pyogenes (three) and Pseudomonas aeruginosa (two). The most frequently isolated anaerobes were Peptostreptococcus spp. (10), Prevotella spp. (seven), micro-aerophilic streptococci (four), Fusobacterium spp. (three) and Bacteroides spp. sensu stricto (three). This study highlights the polymicrobial nature and predominance of anaerobic bacteria in axillary HS and the need for antimicrobial thereby to reflect this.     

Microbiology of liver and spleen abscesses

To study the aerobic and anaerobic microbiology of liver and spleen abscesses and correlate the results with predisposing factors, potential causes and routes of infection, clinical and laboratory data of 48 patients with liver abscesses and 29 with spleen abscesses treated between 1970 and 1990 were reviewed retrospectively. In liver abscesses, a total of 116 isolates (2.4 isolates/specimen) was obtained; 43 were aerobic and facultative species (0.9 isolates/specimen) and 73 were anaerobic species or microaerophilic streptococci (1.5 isolates/specimen). Aerobic bacteria only were isolated from 12 (25%) abscesses, anaerobic bacteria only from eight (17%), and mixed aerobic and anaerobic bacteria from 28 (58%); polymicrobial infection was present in 38 (79%). The predominant aerobic and facultative isolates were Escherichia coli (11 isolates), Streptococcus group D (8), Klebsiella pneumoniae (5) and Staphylococcus aureus (4). The predominant anaerobes were Peptostreptococcus spp. (18 isolates), Bacteroides spp. (13), Fusobacterium spp. (10), Clostridium spp. (10) and Prevotella spp. (4). There were 12 isolates of micro-aerophilic streptococci. S. aureus and beta-haemolytic streptococci were associated with trauma; Streptococcus group D, K. pneumoniae and Clostridium spp. with biliary disease; and Bacteroides spp. and Clostridium spp. with colonic disease. In splenic abscesses, a total of 56 isolates (1.9 isolates/specimen) was obtained; 23 were aerobic and facultative species (0.8 isolates/specimen), 31 were anaerobic species or micro-aerophilic streptococci (1.1 isolates/specimen) and two were Candida albicans. Aerobic bacteria only were isolated from nine (31%) abscesses, anaerobic bacteria from eight (28%), mixed aerobic and anaerobic bacteria from 10 (34%) and C. albicans in two (7%); polymicrobial infection was present in 16 (55%). The predominant aerobic and facultative isolates were E. coli (5 isolates), Proteus mirabilis (3), Streptococcus group D (3), K. pneumoniae (3) and S. aureus (4). The predominant anaerobes were Peptostreptococcus spp. (11 isolates), Bacteroides spp. (5), Fusobacterium spp. (3) and Clostridium spp. (3). S. aureus, K. pneumoniae and Streptococcus group D were associated with endocarditis, E. coli with urinary tract and abdominal infection, Bacteroides spp. and Clostridium spp. with abdominal infection and Fusobacterium spp. with respiratory infection.     

Aerobic and anaerobic microbiology of empyema. A retrospective review in two military hospitals

The microbiology and clinical features of empyema were studied retrospectively in 197 patients whose specimens yielded bacterial growth after inoculation for aerobic and anaerobic bacteria. Three hundred forty-three organisms (216 aerobic or facultative and 127 anaerobic organisms) were isolated. Aerobic bacteria were isolated in 127 (64 percent) patients, anaerobic bacteria in 25 (13 percent), and mixed aerobic and anaerobic bacteria in 45 (23 percent). The predominant aerobic or facultative organisms were Streptococcus pneumoniae (70 isolates), Staphylococcus aureus (58), Escherichia coli (17), Klebsiella pneumoniae (16), and Haemophilus influenzae (12). The predominant anaerobes were pigmented Prevotella and Porphyromonas species (24), Bacteroides fragilis group (22), anaerobic cocci (36), and Fusobacterium species (20). beta-Lactamase-producing organisms were recovered in 49 (38 percent) of 128 tested specimens. These included all 42 tested S aureus and 15 B fragilis group, 4 of 9 K pneumoniae, 3 of 9 H influenzae, 3 of 8 pigmented Prevotella and Porphyromonas species, and 2 of 6 E coli. Most patients from whom S pneumoniae and H influenzae were recovered had pneumonia, and most patients with S aureus had pneumonia, aspiration pneumonia, and lung abscesses. The recovery of anaerobic bacteria was mostly associated with the concomitant diagnosis of aspiration pneumonia, and lung, subdiaphragmatic, dental, and oropharyngeal abscesses. These data highlight the importance of anaerobic bacteria in selected cases of empyema.     

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.     

Otitis media: microbiology and management

Otitis media (OM) is a common childhood disease and one that can cause significant morbidity. A knowledge of the pathogens responsible for OM can assist in the selection of the most appropriate treatment regimen and can minimize complications that may require surgery. The microbiology of acute, serous, and chronic OM is reviewed. The major organisms recovered from about three quarters of acute OM and half of serous OM cultures are Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. Streptococcus pyogenes, anaerobic cocci, and viruses can each be isolated in less than 5% of the patients with acute OM. The predominant organisms isolated from chronic OM are Staphylococcus aureus, Pseudomonas aeruginosa, and anaerobic bacteria. The predominant anaerobes are gram-positive cocci, pigmented Prevotella and Porphyromonas sp, Bacteroides sp, and Fusobacterium sp. Many of the aerobic and anaerobic organisms causing OM can produce beta-lactamase, rendering them resistant to many of the penicillins. The appropriate surgical and medical therapies for acute, serous, and chronic otitis media are discussed.     

Bacteriological study of otogenic cerebral abscesses: chemotherapeutic role of metronidazole

In nine consecutive patients with otogenic cerebral abscesses a mixed growth of aerobic and obligate anaerobic bacteria was isolated from the pus in five patients, and in the remaining four obligate anaerobes were the sole isolates. The commonest obligate anaerobe isolated was Bacteroides fragilis, which was present in all but one patient. The patients were all treated with metronidazole for the anaerobic organisms and with appropriate chemotherapy against the aerobic organisms isolated. All the patients recovered and only one was left with a neurological deficit. As otogenic cerebral abscesses constitute a major proportion of all cerebral abscesses, the use of metronidazole against obligate anaerobic bacteria, which tend to dominate in such abscesses, should reduce the high mortality from this condition.     

Making the best use of consultant orthodontic services, Part 2: How to undertake the referral

There is little information on the microbiology of periapical lesions, and no data on the residual microbial flora in the periapex, if any, after apicoectomy procedures. Hence, 64 patients treated by apicoectomy procedures were prospectively studied to assess the bacterial flora in the periapex and to evaluate the residual bacteria in postoperative apicoectomy sites. Of the 64 lesions studied, 14 (22%) were sterile and 50 (78%) yielded bacteria preoperatively. Bacteria could be recovered from 28 (56%) of the latter lesions after apicoectomy and curettage. A total of 105 bacterial strains was isolated from 50 lesions, yielding a range of 1-4 (mean 2.1) species per sample. The isolates comprised 84 (80%) facultative anaerobes and 21 (20%) strict anaerobes. A polymicrobial growth was obtained from 39 lesions whilst 11 lesions yielded pure cultures. On detailed microbiological analyses of 29 lesions, 40% of the isolates were identified as alpha-haemolytic streptococci, half of which were Streptococcus sanguis; anaerobic streptococci were the predominant anaerobes. None of the organisms or group(s) of organisms emerged as recalcitrant colonisers which were difficult to dislodge after surgical debridement. These data indicate that the majority of periapical lesions harbour a variety of flora which cannot be eradicated despite thorough apicoectomy procedures.     

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.     

In vitro activity of Bay 12-8039, a new 8-methoxyquinolone, compared to the activities of 11 other oral antimicrobial agents against 390 aerobic and anaerobic bacteria isolated from human and animal bite wound skin and soft tissue infections in humans

The in vitro activity of Bay 12-8039, a new oral 8-methoxyquinolone, was compared to the activities of 11 other oral antimicrobial agents (ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin, azithromycin, clarithromycin, amoxicillin clavulanate, penicillin, cefuroxime, cefpodoxime, and doxycycline) against 250 aerobic and 140 anaerobic bacteria recently isolated from animal and human bite wound infections. Bay 12-8039 was active against all aerobic isolates, both gram-positive and gram-negative isolates, at < or = 1.0 microg/ml (MICs at which 90% of isolates are inhibited [MIC90s < or = 0.25 microg/ml) and was active against most anaerobes at < or = 0.5 microg/ml; the exceptions were Fusobacterium nucleatum and other Fusobacterium species (MIC90s, > or = 4.0 microg/ml) and one strain of Prevotella loeschii (MICs, 2.0 microg/ml). In comparison, the other quinolones tested had similar in vitro activities against the aerobic strains but were less active against the anaerobes, including peptostreptococci, Porphyromonas species, and Prevotella species. The fusobacteria were relatively resistant to all the antimicrobial agents tested except penicillin G (one penicillinase-producing strain of F. nucleatum was found) and amoxicillin clavulanate.     

Operation for retinal detachment caused by holes in the posterior pole area, simple, long-tolerated silver span and cerclage (author''s transl)

Quantitative bacteriology was performed on vaginal secretions from healthy adult women. The analysis included a single sample from 17 college students and 35 samples from five volunteers collected at intervals of three to five days throughout the menstrual cycle. Mean concentrations in all 52 specimens were 10(8.1) aerobic bacteria/g and 10(9.1) anaerobic bacteria/g. The rank of predominant organisms, according to rates of recovery in concentrations of greater than 10(5) colony-forming units/g, was anaerobic and facultative Lacrobacillus species, Peptococcus species, Bacteroides species, Staphylococcus epidermidis, Corynebacterium species, Peotostreptococcus species, and Eubacterium species. Sequential samples collected throughout the menstrual cycle showed relatively consistent mean levels of anaerobes and a significant decrease in concentrations of aerobes in premenstrual specimens compared with those in the specimens collected in the week following onset of menses. Analysis of sequential specimens from each of the five individuals showed considerable variation in species recovered. These data indicate that the vaginal flora in healthy adult women is a dynamic ecosystem in which anaerobes are usually the numerically dominant bacteria.     

Organisms isolated from dogs and cats with anaerobic infections and susceptibility to selected antimicrobial agents

OBJECTIVE: To determine the prevalence of obligate anaerobic bacteria in bacterial infections in dogs and cats and susceptibility to selected antimicrobial agents. DESIGN: Case series. SAMPLE POPULATION: Specimens from 1,267 dogs and 243 cats. PROCEDURE: Standard anaerobic and aerobic bacterial culture methods were used. Anaerobic isolates were tested for susceptibility to selected antimicrobial agents. RESULTS: Obligate anaerobic bacteria were isolated from 199 (15.7%) and 69 (28.4%) specimens obtained from dogs and cats, respectively. More than half of the specimens that contained obligate anaerobic bacteria were from draining tracts (exclusively dogs), pleural fluid, abscesses, bones, the respiratory tract, or the abdominal cavity. The most commonly isolated obligate anaerobic bacteria (approx 70% of all isolates) were Bacteroides spp, Peptostreptococcus spp, Fusobacterium spp, and Porphyromonas spp. Eighty percent of the specimens that contained obligate anaerobic bacteria also contained facultative anaerobic or aerobic organisms. The organisms most commonly isolated in association with obligate anaerobic bacteria were members of the family Enterobacteriaceae (Escherichia coli was the most common), Pasteurella spp, and Staphylococcus intermedius. Ninety-seven obligate anaerobic isolates were tested for susceptibility to ampicillin, amoxicillin-clavulanic acid, chloramphenicol, clindamycin, and metronidazole. All were susceptible to amoxicillin-clavulanic acid and chloramphenicol, and most were susceptible to metronidazole. Only 71% of the Bacteroides isolates were susceptible to ampicillin, and only 83% were susceptible to clindamycin. Only 80% of the Clostridium isolates were susceptible to clindamycin, but all were susceptible to ampicillin. CLINICAL IMPLICATIONS: Data on sites and conditions from which anaerobic bacteria are commonly isolated, along with results of susceptibility testing, may be useful in designing antimicrobial treatment regimens.     

Bacteriology of the lower respiratory tract as determined by fiber-optic bronchoscopy and transtracheal aspiration

For assessment of the validity of cultures of tracheobronchial secretions and exudates (TBSE) obtained by fiber-optic bronchoscopy, the aerobic and anaerobic flora of expectorated saliva and TBSE obtained by fiber-optic bronchoscopy from nine healthy volunteers and eight patients were compared with those obtained by fiber-optic bronchoscopy as well). Normal volunteers yielded both aerobic and anaerobic bacteria in amounts usually less than 104.5 colony-forming units (cfu)/ml in TBSE obtained by fiberoptic bronchoscopy. In patients with chronic bronchitis, 42 isolates of aerobic bacteria (104-105.5 cfu/ml) and only 10 isolates of anaerobes (usually less than 104 cfu/ml) were reovered from 15 samples obtained by trantracheal aspiration. The data lead to the conclusion that low-level contamination (less than or equal to 104 cfu/ml) with oral flora is common in TBSE obtained by fiber-optic bronchoscopy. A single potential pathogen in numbers of greater than or equal to 105 cfu/ml may be of etiologic significance, particularly if recovered from purulent drainage material from a localized portion of the lung. Under circumstances in which quantitative bacteriology cannot be done, TBSE obtained by transtracheal aspiration will most reliably reflect the bacterial flora present in the lung.     

Coal miners'' respiratory disease litigation

Between 1985 and 1995, 1037 bacteremic episodes were recorded in a pediatric tertiary care center and analyzed retrospectively. Gram-positive bacteria accounted for 719 episodes (68%), gram-negative bacteria for 303 (29%), fungi for 16 (2%), and anaerobes for 12 (1%). In 526 (51%) patients, primarily neonates and oncology patients, a predisposing condition was present. In 390 (38%) episodes a clinical source of infection was documented. Mortality was highest in Pseudomonas bacteremia (45%). Since the bacterial spectrum differed widely between patient groups, the choice of empirical antimicrobial therapy should be based on any underlying condition present in the patient and the clinical source of infection. As anaerobes were rarely isolated. the routine use of anaerobic blood cultures in patients without predisposing conditions does not seem warranted.     

A study of the anaerobic bacterial flora of the female genital tract in health and disease

Semi-quantitative and qualitative bacterial assessment of the vaginal and cervical flora of a total of 202 women was carried out over a period of six months to determine the bacterial flora in three groups of women and changes caused by prior use of antibiotics. The number was made up of 32 healthy volunteers, 80 women with gynaecological problems and 90 women with gynaecological infections who had had antibiotic treatment prior to this study. Standard methods were used for the investigations. Five main genera of anaerobic bacteria were isolated from all patients. They included, the Bacteroides spp., Prevotella spp., Porphyromonas spp., Peptostreptococcus spp. and Clostridium spp. Five non-sporing gram negative anaerobic bacteria constituted the bulk of the flora including Prevotella bivia, P. disiens, P. melanogenica, P. asaccharolytica and B. fragilis. The predominant flora was P. bivia occurring in 61 pc of cervical swab specimens of the 80 women with proven gynaecological infections who had not used antibiotics and accounting for 27 pc of the total number of Gram-negative anaerobic bacteria isolated. Escherichia coli and Staphylococcus epidermidis were the most frequently encountered aerobic bacteria. The semi-quantitative counts of the different bacterial species in the patient group were significantly higher than in the control group of healthy individuals (p < 0,025). Similarly, prior antibiotic administration significantly reduced the population and quantitative count of the anaerobic bacteria.     

Antimicrobial susceptibility of subgingival bacterial flora in dogs with gingivitis

The aerobic and anaerobic flora from gingival pockets of 49 dogs with severe gingivitis and periodontitis were cultured. The susceptibility of each isolate to four antimicrobial agents currently approved for veterinary use in the USA (amoxicillin-clavulanic acid; clindamycin; cefadroxil; and enrofloxacin) was determined. Amoxicillin-clavulanic acid (Clavamox Pfizer Animal Health) had the highest in-vitro susceptibility against all isolates (96%), all aerobes (94%) and all anaerobes (100%) tested. For gram-negative aerobes, enrofloxacin (Baytril, Bayer Corp.) had the highest in-vitro susceptibility activity. For bacteria associated with treatment of gingivitis, which typically are mixed aerobic/anaerobic and gram-positive/gram-negative organisms, the antimicrobial of choice for clinical use based on these susceptibility tests is amoxicillin-clavulanic acid.