Cave canem: HBO2 therapy efficacy on Capnocytophaga canimorsus infections: a case series.

BACKGROUND: Dog bites are a frequent injury, but the incidence and type of lesions vary across countries. Although only few patients develop complications, the treatment of advanced injuries has a considerable medical, social and economic impact. A frequently isolated pathogen in dog bite wounds is Capnocytophaga canimorsus, a bacterium that can cause sepsis or meningitis. Hyperbaric oxygen (HBO2) therapy has been shown to be useful in treating anaerobic infections, most likely because it creates an inhospitable environment for the bacterium and enhances the patient's immune response. AIM: We present a case series of C. canimorsus infections treated with HBO2 in adjunction to antibiotic therapy. Furthermore, we tested the in vitro activity of ceftaroline against C. canimorsus, alone and in association with hyperbaric oxygen therapy. METHODS: We included nine (9) patients admitted to the surgery department of "A. Cardarelli" Hospital (Naples) after dog bite, from 2010 to 2016. All were initially treated with antibiotics and required transfer to the intensive care unit due to worsening conditions. C. canimorsus was isolated from wounds, and HBO2 therapy was administered in adjunction to antibiotics, until clinical improvement and microbiological test negativity. We tested the activity of hyperbaric oxygen therapy in adjunction to ceftaroline on cultured plates with C. canimorsus versus ceftaroline alone. Minimal inhibitory concentration was evaluated. CONCLUSIONS: Our findings confirm the utility of HBO2 therapy after biting injuries. Indeed, increased oxygen supply to the wound (as well as in vitro) may be toxic for bacteria, can improve healing and may improve the effectiveness of antibiotics.

Ceftaroline versus isolates from animal bite wounds: comparative in vitro activities against 243 isolates, including 156 Pasteurella species isolates.

More than 5 million Americans are bitten by animals, usually dogs, annually. Bite patients comprise ∼1% of all patients who visit emergency departments (300,000/year), and approximately 10,000 require hospitalization and intravenous antibiotics. Ceftaroline is the bioactive component of the prodrug ceftaroline fosamil, which is FDA approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs), including those containing methicillin-resistant Staphylococcus aureus (MRSA). There are no in vitro data about the activity of ceftaroline against Pasteurella multocida subsp. multocida and Pasteurella multocida subsp. septica, other Pasteurella spp., or other bite wound isolates. We therefore studied the in vitro activity of ceftaroline against 243 animal bite isolates. MICs were determined using the broth microdilution method according to CLSI guidelines. Comparator drugs included cefazolin, ceftriaxone, ertapenem, ampicillin-sulbactam, azithromycin, doxycycline, and sulfamethoxazole-trimethoprim (SMX-TMP). Ceftaroline was the most active agent against all 5 Pasteurella species, including P. multocida subsp. multocida and P. multocida subsp. septica, with a maximum MIC of ≤0.008 µg/ml; more active than ceftriaxone and ertapenem (MIC(90)s, ≤0.015 µg/ml); and more active than cefazolin (MIC(90), 0.5 µg/ml) doxycycline (MIC(90), 0.125 µg/ml), azithromycin (MIC(90), 0.5 µg/ml), ampicillin-sulbactam (MIC(90), 0.125 µg/ml), and SMX-TMP (MIC(90), 0.125 µg/ml). Ceftaroline was also very active against all S. aureus isolates (MIC(90), 0.125 µg/ml) and other Staphylococcus and Streptococcus species, with a maximum MIC of 0.125 µg/ml against all bite isolates tested. Ceftaroline has potential clinical utility against infections involving P. multocida, other Pasteurella species, and aerobic Gram-positive isolates, including S. aureus.

Clinical and bacteriological assessment of dog-to-dog bite wounds.

Although dog-to-dog bite wounds are frequent, few studies correlate bacterial involvement to clinical aspects. This work aimed at relating clinical evolution and bacteriological data, with the evolution time (ET), i.e., the period of time elapsed from aggression until presentation. A total of 228 wounds from 83 cases of bitten dogs was evaluated; 48 of the wounds were sampled for bacteriology. Dogs with clinically infected wounds (N=29) were subjected to antimicrobial therapy and local disinfection. Dogs without clinical signs of infection were either subjected to the same treatment (N=43) or only subjected to daily wound saline irrigation (N=11), to evaluate the need for antimicrobial prophylaxis. The majority of wounds were laceration and puncture wounds with dermis penetration (41.2% and 23.2%, respectively). Only 17% of the wounds were clinically infected. The mean ET was 39h 30m and prolonged ET was significantly correlated to infection. None of the wounds from animals not given antibiotics became infected. Bacteriology was positive in 95.8% of the wounds sampled (N=46). A total of 125 isolates was obtained, mostly aerobes. Clinical infection was associated with the presence of strict anaerobes. Excluding antibiotics that should be preserved for life-threatening cases, the higher rates of in vitro antimicrobial susceptibility were observed for sulphamethoxazole-trimethoprim (94.4%) and amoxicillin-clavulanate (91.9%). This study identified the time lag from aggression to presentation as a risk factor for infection development. Further studies are required to evaluate the actual requirement for antimicrobial therapy when only dermis is affected in dog-to-dog bite wounds.

Why your housecat's trite little bite could cause you quite a fright: a study of domestic felines on the occurrence and antibiotic susceptibility of Pasteurella multocida.

Approximately four to five million animal bite wounds are reported in the USA each year. Domestic companion animals inflict the majority of these wounds. Although canine bites far outnumber feline bites, unlike the dog, the cat's bite is worse than its bark; 20-80% of all cat bites will become infected, compared with only 3-18% of dog bite wounds. Pasteurella multocida is the most commonly cultured bacterium from infected cat bite wounds. Anyone seeking medical attention for a cat-inflicted bite wound is given prophylactic/empiric penicillin or a derivative to prevent Pasteurella infection (provided they are not allergic to penicillins). In an effort to establish a carriage rate of P. multocida in the domestic feline, bacterial samples from the gingival margins of domestic northern Ohio cats (n=409) were cultured. Isolates were tested for antibiotic sensitivity as prophylactic/empiric use of penicillin and its derivatives could potentially give rise to antibiotic resistance in P. multocida. The high carriage rate (approximately 90%) of P. multocida observed was found to be independent of physiological and behavioural variables including age, breed, food type, gingival scale, lifestyle and sex. High antibiotic susceptibility percentages were observed for benzylpenicillin, amoxicillin-clavulanate, cefazolin, and azithromycin (100%, 100%, 98.37% and 94.02%, respectively) in P. multocida isolates. The high prevalence of P. multocida in the feline oral cavity indicates that prophylactic/empiric antibiotic therapy is still an appropriate response to cat bite wounds. Additionally, the susceptibility of P. multocida to penicillin and its derivatives indicates that they remain reliable choices for preventing and treating P. multocida infections.

The bacteriology and antimicrobial susceptibility of infected and non-infected dog bite wounds: fifty cases.

Dog bite wounds are a common reason for dogs requiring veterinary care, but there is surprisingly little data on the bacteriology of bite wounds. A prospective study was performed on dogs with various grades of bite wound to identify the bacteria present in these wounds. Swabs were collected from all wounds for bacterial culture and cytology. All swabs were cultured aerobically and anaerobically and all aerobic cultures were evaluated for antibiotic susceptibility using the Kirby Bauer disk diffusion test. Fifty dogs with 104 bite wounds, inflicted within the previous 72h, were included. The victims were predominately intact male small breed dogs. Of the 104 wounds, 21 were judged by cytology to be infected and 83 non-infected. Infected wounds were significantly more likely to culture positive (p=0.02). Sixteen percent of wounds showed no growth. Sixteen percent grew aerobes, 1% anaerobes and 67% a mixture of aerobes and anaerobes. Pasteurella canis and pyogenic streptococci were common in infected wounds, whereas Bacillus spp., Actinomyces spp. and the oral streptococci were usually found in contaminated wounds. Three anaerobic genera were cultured, namely, Prevotella, Clostridium and Peptostreptococcus. One case represented the first isolation of Capnocytophaga canimorsus in an infected dog bite wound. Although no single antibiotic therapy was considered to be effective against all the bacteria, amoxycillin plus clavulanic acid, 1st and 3rd generation cephalosporins ampicillin or amoxycillin and potentiated sulphonamides gave the best in vitro sensitivity results.

Successful treatment of Pasteurella multocida meningitis with aztreonam.

This is the first reported case of the successful treatment of Pasteurella multocida meningitis with aztreonam in a patient with multiple antibiotic allergies.

Rat bite fever without fever.

Rat bite fever is a rarely reported acute febrile bacterial illness caused by Streptobacillus moniliformis or Spirillum minus following a rat bite. It is classically characterised by abrupt onset of fever with rigors, myalgias, headache, and the appearance of a generalised maculopapular petechial skin rash. Polyarthritis complicates the course of the disease in up to 50% of infected patients, and numerous hurdles can make the diagnosis particularly difficult in the absence of fever or rash, as in the present case. A high degree of awareness is necessary to make the correct diagnosis in such cases. Diagnosis has important prognostic implications as the disease is potentially lethal, but easily treatable.

Dog-bite wounds: bacteriology and treatment outcome in 37 cases.

Bite wounds in 37 dogs were prospectively evaluated. Ninety-five percent of animals presented within 12 hours of injury. The most common wound locations were neck, limbs, head, chest, shoulder region, and abdomen. Eighty-six percent had wounds to multiple locations. Fifty-seven percent of wounds were Class 4 (i.e., most severe). Based on results of all samples, 65% had positive aerobic cultures, 15% had positive anaerobic cultures, and 33% had negative cultures. The most commonly isolated aerobic bacteria were Staphylococcus intermedius, Enterococcus spp., Staphylococcus coagulase negative, and Escherichia coli. Most common anaerobic isolates were Bacillus spp., Clostridium spp., and Corynebacterium spp. Severe bite wounds had a high rate of bacterial contamination at presentation. No single antibiotic or antibiotic combination was effective against all bacteria that were cultured.

Characterization of Bacteroides forsythus strains from cat and dog bite wounds in humans and comparison with monkey and human oral strains.

Bacteroides forsythus strains recovered from cat and dog bite wound infections in humans (n = 3), monkey oral strains (n = 3), and the human oral ATCC 43037 type strain were characterized by using phenotypic characteristics, enzymatic tests, whole cell fatty acid analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, PCR fingerprinting, and 16S rDNA (genes coding for rRNA) sequencing. All three bite wound isolates grew on brucella agar supplemented with 5% sheep blood, vitamin K1, and hemin. These strains, unlike the ATCC strain and previously described monkey oral and human clinical strains, did not require N-acetylmuramic acid supplementation for growth as pure cultures. However, their phenotypic characteristics, except for catalase production, were similar to those of previously identified strains. PCR fingerprinting analysis showed differences in band patterns from the ATCC strain. Also, SDS-PAGE and whole cell fatty acid analysis indicated that the dog and cat bite wound strains were similar but not identical to the human B. forsythus ATCC 43037 type strain and the monkey oral strains. The rDNA sequence analysis indicated that the three bite wound isolates had 99.93% homology with each other and 98.9 and 99.22% homology with the human ATCC 43037 and monkey oral strains, respectively. These results suggest that there are host-specific variations within each group.

Growth characteristics and a novel method for identification (the WEE-TAB system) of Porphyromonas species isolated from infected dog and cat bite wounds in humans.

Thirty-nine clinical isolates of Porphyromonas species recovered from infected cat and dog bite wounds in humans and eight American Type Culture Collection and National Collection of Type Cultures type strains were characterized by using the API ZYM system, the RapID ANA II system, and conventional biochemical methods. Growth characteristics on various agar media were compared. All strains grew on brucella blood agar supplemented with vitamin K1 and hemin and on brucella laked blood agar supplemented with vitamin K1 and hemin. In contrast, only 34% of strains grew on unsupplemented brucella blood agar, 62% grew on Columbia blood agar, and 70% grew on tryptic soy blood agar (the last three media did not contain vitamin K1 or hemin). The ability of the single-tube, triple-substrate WEE-TAB system to detect the preformed enzymes N-acetyl-beta-D-glucosaminidase, alpha-D-galactosidase, beta-D-galactosidase, alpha-fucosidase, trypsin-like activity, and chymotrypsin was evaluated. The WEE-TAB test results were easy to interpret; the WEE-TAB tests were more sensitive than the comparable tests with the API ZYM and RapID ANA II systems for the detection of alpha-D-galactosidase, beta-D-galactosidase, trypsin, and chymotrypsin, and the WEE-TAB tests accurately identified Porphyromonas species.

Comparative in vitro activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against 387 aerobic and anaerobic bite wound isolates.

The activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against bite wound isolates were determined by the agar dilution method. DU-6859a was the most active compound (MICs, < or = 0.125 microg/ml) against all Pasteurella species, Staphylococcus aureus, and streptococci; anaerobes were susceptible to < or = 0.5 microg/ml, except fusobacteria, which were susceptible to < or = 2 microg/ml. Against aerobes, levofloxacin was more active than ofloxacin (MIC at which 90% of isolates are inhibited [MIC90], < or = 1.0 microg/ml for both) and sparfloxacin and ciprofloxacin were also active (MIC90s, < or = 0.25 and < 1 microg/ml, respectively).

Susceptibility of bite wound bacteria to seven oral antimicrobial agents, including RU-985, a new erythromycin: considerations in choosing empiric therapy.

The susceptibility of 93 aerobic and 59 anaerobic bacteria isolated from human and animal bite wounds was determined by agar dilution. No agent tested (penicillin, oxacillin, cephalexin, sulfamethoxazole-trimethoprim, minocycline, erythromycin, and RU-965) was consistently active against all isolates. A total of 21% of the Bacteroides species, all isolated from human bites, were resistant to penicillin; 14 and 18% of the Pasteurella multocida isolates were resistant to erythromycin and oxacillin, respectively.

[Antibacterial therapy in treating the wound after animal bites]. / Antibakterial'naia terapiia pri lechenii ran posle ukusov zhivotnykh.

A total of 150 patients with wounds due to animal bites were treated. The bacteriological analysis showed that during the first 24 hours after the bite the main microbes isolated from the wound contents were staphylococci and Coli bacteria. At later periods gramnegative microflora predominated. Prolonged washing of the wounds with furacin and sodium bicarbonate, 2 per cent boric acid after the wound dissection with establishing primary and secondary sutures, antibacterial therapy with semisynthetic penicillins and monomycin provided rapid healing of the wounds in 144 patients.