Polymicrobial tenosynovitis with Pasteurella multocida and other gram negative bacilli after a Siberian tiger bite

Mammalian bites present a considerable clinical problem because they are often associated with bacterial infections. Pasteurella multocida is a microorganism that commonly infects both canine and small feline bites. Zoonotic infections developing after large feline bites have been recognised, although their reports are limited. We describe a 35 year old man who was bitten by a Siberian tiger and who developed infectious tenosynovitis secondary to P multocida, Bergeyella (Weeksella) zoohelcum, and Gram negative bacteria most like CDC group EF-4b and comamonas species. The latter three bacteria have not been isolated previously from large feline bite wounds.     

Wound management: the occlusive dressing

Superficial wounds resulting from athletic injury are common in sports medicine. Although such wounds can be quite painful, they are usually merely inconvenient to the athlete. If improperly managed, however, superficial wounds may heal slowly and cause unnecessary scar tissue proliferation at the wound site. Scar formation causes the wound to break open frequently and puts the athlete at risk of cross-contamination by pathogenic organisms. New advances in the science of wound management strongly favor the use of occlusive dressings to increase patient comfort, increase patient compliance, decrease the risk of infection, and decrease overall healing time. Occlusion has clearly been proven to aid in the healing of superficial wounds and should be considered as a treatment alternative for wounds in the sports medicine setting. In this paper, I discuss three of the most widely used types of occlusive dressings: 1) films, 2) hydrogels, and 3) hydrocolloids.     

Protothecosis: report of a case with 20-year follow-up, and review of previously published cases

We present a Prototheca wickerhamii wound infection case that failed treatment with ketoconazole but was cured with amphotericin-B plus tetracycline. The patient was immunocompetent but had had local steroid injections. We reviewed another 159 cases from the literature. Prototheca has infected many areas of the human body, but most often skin, olecranon bursa, or wounds. Prior treatment with steroids and immune deficiencies are contributing factors. Itraconazole and fluconazole are reasonable initial treatments for patients with mild infections. For serious infections, or for infections that have failed azole treatment, amphotericin-B is the treatment of choice.     

Pasteurella multocida: a case report of bacteremic pneumonia and 10-year laboratory review

Pasteurella multocida is a normal oral commensal in animals. Animal bites are often complicated by severe wound infection due to P. multocida, but systemic infection is rare. We report a patient with bacteremic pneumonia successfully treated with ceftriaxone and ciprofloxacin. We also review the clinical isolates of P. multocida reported by a major teaching hospital laboratory over a 10-year period. There were 23 patients, comprising the present case, 17 patients with wound infections following animal bites, one case of neonatal meningitis and associated maternal vaginal carriage of P. multocida, and three sputum isolates of doubtful significance.     

Wound infections following posterior spinal instrumentation for paralytic scoliosis

Objectives: To investigate in a prospective study the infection rate, the bacteriology and the outcome of wound infections following posterior spinal instrumentation in children and young adolescents during 1993–96.
Methods: Fifty patients, who underwent spinal instrumentation because of paralytic scoliotic deformity, were followed by the surgeon, the clinical microbiologist and the infection control nurse. In those patients with clinical and laboratory findings suggesting wound infection, multiple swabs and tissue biopsies were obtained from deep within the infected wound and were cultured on appropriate media. Microorganisms were identified by conventional methods.
Results: Ten of 50 patients (20%) developed early deep wound infections, most of them polymicrobial, 3–9 days after the operation. Coagulase-negative staphylococci (70.0%), Enterobacteriaceae (17.3%), anaerobes (5.4%) and Staphylo-coccus aureus (3.7%) were isolated from the wound specimens. S. epidermidis strains were the predominant isolates. All coagulase-negative staphylococci were multiresistant to β-lactams, aminoglycosides, fusidic acid and co-trimoxazole, while most of them were susceptible to rifampicin and quinolones. All wounds healed uneventfully with aggressive debridement and prolonged antimicrobial therapy.
Conclusions: Postoperative wound infection is a significant complication of spinal instrumentation. Multiresistant coagulase-negative staphylococci are the predominant pathogens. Successful treatment includes wound debridement and prolonged antimicrobial therapy.     

Tick bites in a Lyme borreliosis highly endemic area in Switzerland

The duration of tick feeding is an important indicator to evaluate the risk of Borrelia burgdorferi sensu lato transmission, which increases considerably with the blood meal duration. This blood meal duration may be estimated from scutal index, the ratio between body length (idiosoma) and scutum width. For the estimation of blood meal duration in Ixodes ricinus, nymphal and adult female ticks were detached at predetermined intervals (24, 48, 72, and 96h) from laboratory mice and rabbits and their scutal index calculated. From this, non-linear regression equations were developed to determine the duration of attachment for nymphal and adult female I. ricinus ticks. As part of an epidemiological study addressing the risk of subclinical (seroconversion) and clinical infections after a tick bite in the Neuchatel area (Switzerland) over 3 years (2003-2005), duration of tick attachment and anatomical site of bites collected on participants as well as seasonal distribution of tick bites were studied. Tick attachment duration was estimated in all ticks collected during this study (n=261). Nymphs were attached for a mean (+/- standard error, SE) of 31.6h (+/-2.6) and females for a mean (+/-SE) of 29.6h (+/-3.2). Most nymphs were removed after 24h of blood meal whereas most females were removed before 24h. Legs were the major anatomical sites of bites for women (40.7%), men (44.4%), and almost all age classes. Only children <10 years old were bitten more frequently on the head (41.2%) and on the neck (38.5%) than participants >10 years. The majority of tick bites were recorded from May to July during the 3 years. Attachment sites can influence the discovery of ticks, hence the duration of the tick bite. A detailed body examination after each outing in forest and an early withdrawal of an attached tick is an effective way to prevent Lyme borreliosis.     

Different test situations for measuring offensive aggression in male rats do not result in the same wound patterns

It has been reported by the Blanchards, that the attacks of offensively motivated rats produce a very characteristic wound distribution on the body of opponents, the back region being the most prominent target area. We now report that the distribution of wounds on male intruders produced by male resident Wistar rats in a resident-intruder paradigm, depends on the experimental situation used. Rats solitarily housed in small cages (0.1 m²), produced most wounds (57%) on the upper back, about 14% on the lower back, whereas head and belly were much less bitten. Rats housed in larger cages (0.52 m²) with a female (“territorial situation”) produced about 39% of the wounds on the back, equally divided over the anterior and posterior parts. In this situation the head (21%) and the belly (23%) were more frequently bitten than in the other test situations. In a large colony (5.7 m²), practically all wounds were situated dorsally (81%), the majority (58.5%) on the lower part of the back. It was concluded that the distribution of wounds over the body of the intruder was at least partly determined by the possibility of escape.     

Vibrio vulnificus endometritis

Vibrio vulnificus most frequently causes wound infections contracted after exposure to seawater or primary septicemias resulting from the consumption of raw oysters. We report a case of endometritis caused by V. vulnificus. The infection was apparently acquired during the act of sexual intercourse in seawater in an area in which V. vulnificus has been frequently isolated. The efficacy of treatment with an antimicrobial regimen which included tetracycline is discussed.     

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.     

Prevention of dog bites: Evaluation of a brief educational intervention program for preschool children

Dog bites are an underestimated societal problem. Victims suffer injuries, both physical and emotional, that sometimes end in death, and the economic cost to the community is high. The most frequent victims are children, many of whom are bitten at home. Current interventions, primarily aimed at the control of dogs in public areas, appear unlikely to reduce the incidence of dog bites within this group. In this study, parents' beliefs about their children's behavior around familiar and strange dogs were investigated using a questionnaire. The impact of a brief educational dog safety program on 192 kindergarten children (M = 4.68 years of age) was then evaluated. The questionnaire data revealed that many children engage in unsafe behaviors around dogs, and that parents are largely unaware of the dangers associated with such behaviors. The dog safety program resulted in a significant increase in the ability of children to identify high risk situations for up to 4 weeks, with the benefits being even greater in those children whose parents were also given information regarding safe behaviors around dogs. © 2003 Wiley Periodicals, Inc.     

Pneumonia and bacteremia caused by a previously undescribed Moraxella-like bacterium.

Immunocompromised patients are frequently subject to unusual infections. We recently treated a renal allograft recipient for pneumonia due to a hitherto undescribed Moraxella-like bacterium which most closely resembles M-5. M-5 has previously been associated in humans only with dog bites and wound infections. The patient responded well to treatment with aminoglycosides and cephalosporins. Susceptibility to these drugs was demonstrated in vitro by a broth dilution technique. On the basis of the known ability of Moraxella species to colonize the oropharynx and the patient's lack of animal exposure, we propose that our patient's illness was secondary to aspiration of colonized oropharyngeal contents.     

The changing epidemiology of severe infections in the ICU

Data on the epidemiology of severe infection in the intensive care unit (ICU) can be used to monitor the effect of preventive measures and changes in policy or procedures. The most common risk factors associated with ICU-acquired infection include length of stay, antibiotic usage, catheterization and use of other invasive devices. The most frequent infections encountered in ICU patients include lower respiratory tract infections (especially pneumonia) and bacteremia, in addition to urinary tract infections and wound infections. Streptococcus pneumoniae, Haemophilus influenzae , methicillin susceptible Staphylococcus aureus and Enterobacteriaceae are most often implicated in community-acquired and early onset ICU-acquired infections, whereas late onset infection is more likely to be caused by pathogens which are more refractory to treatment, such as Enterobacter spp., Serratia spp., Pseudomonas aeruginosa, Acinetobacter spp. and methicillin-resistant S. aureus (MRSA). The pathogen spectrum also varies according to the site of infection, with Gram-positive bacteria being most frequently isolated in bacteremia and wound infections, whereas Gram-negative bacteria are prevalent in late-onset pneumonia and urinary tract infections. The prevalence of Gram-positive pathogens in bacteremia has increased over the past 20 years, mainly because of the increased isolation of coagulase-negative staphylococci (CNS) and enterococci. This is most probably due to the selective pressure exerted by the use of broad-spectrum antibiotics, such as the third-generation cephalosporins and fluoroquinolones, which are generally more potent against Gram-negative than Gram-positive bacteria, and to the increased use of invasive devices.
The increasing isolation frequency of Gram-positive pathogens in severe ICU infections has resulted in greater usage of vancomycin, which may account for the rising incidence of vancomycin-resistant enterococci.     

Plasmodium falciparum transmission intensity and infection rates in children in Gabon

Several factors can determine the outcome of a malarial infection. Studies on susceptibility or resistance to malarial infection can be confounded by differences in transmission. In the present study, the relationship between vector abundance and Plasmodium falciparum infection rate of Gabonese children was studied. Indoor human bait catches were conducted in the houses of two groups of children, those who had been found earlier to be either frequently (> 3 infections per year) or rarely (< 0.5 infections per year) infected with P. falciparum. The human biting rate was 12 and 31 bites per person per night during the dry and the rainy season, with 3% and 16% Anopheles, respectively. Anopheles gambiae and A. moucheti were found to be the only vectors involved in the transmission of malaria in this area. No significant difference in the abundance and the rate of P. falciparum infection of the Anopheles mosquitoes was found among children rarely or frequently infected. Differences in transmission cannot account for differences in infection rates in our study group. Hereditary and immunological factors seem to be the primary determinants for the outcome of malarial infection.     

A wide spectrum of fastidious and ampicillin-susceptible bacteria dominate in animal-caused wounds

The main purpose of this study was to assess the actual occurrence of Gram-negative oxidase-positive bacteria (GNOP) in human wounds caused by animals, mostly cat and dog bites and scratches, and with signs of infection. We report a prospective series of 92 wound samples. Routine culturing was combined with a procedure optimised for fastidious GNOP. All GNOP isolates were identified by 16S rDNA sequencing to the species level. We observed a more prominent role of GNOP, including at least 30 species mostly in the families Flavobacteriaceae, Neisseriaceae and Pasteurellaceae, and less of Staphylococcus aureus and streptococci. The antibiotic susceptibility pattern was investigated, as GNOP are associated with sudden onset of serious infections, making an early decision on antibiotic treatment vital. All GNOP isolates judged to be clinically relevant displayed susceptibility to ampicillin and meropenem, but resistance to oxacillin, clindamycin and gentamicin was frequent. Our findings emphasise the need to cover GNOP as recommended in guidelines, and not only common wound pathogens, when treating an animal-caused wound.     

Perioperative antibiotic prophylaxis for herniorrhaphy and breast surgery

We assessed the efficacy of perioperative antibiotic prophylaxis for surgery in a randomized, double-blind trial of 1218 patients undergoing herniorrhaphy or surgery involving the breast, including excision of a breast mass, mastectomy, reduction mammoplasty, and axillary-node dissection. The prophylactic regimen was a single dose of cefonicid (1 g intravenously) administered approximately half an hour before surgery. The patients were followed up for four to six weeks after surgery. Blinding was maintained until the last patient completed the follow-up and all diagnoses of infection had been made. The patients who received prophylaxis had 48 percent fewer probable or definite infections than those who did not (Mantel-Haenszel risk ratio, 0.52; 95 percent confidence interval, 0.32 to 0.84; P = 0.01). For patients undergoing a procedure involving the breast, infection occurred in 6.6 percent of the cefonicid recipients (20 of 303) and 12.2 percent of the placebo recipients (37 of 303); for those undergoing herniorrhaphy, infection occurred in 2.3 percent of the cefonicid recipients (7 of 301) and 4.2 percent of the placebo recipients (13 of 311). There were comparable reductions in the numbers of definite wound infections (Mantel-Haenszel risk ratio, 0.49), wounds that drained pus (risk ratio, 0.43), Staphylococcus aureus wound isolates (risk ratio, 0.49), and urinary tract infections (risk ratio, 0.40). There were also comparable reductions in the need for postoperative antibiotic therapy, non-routine visits to a physician for problems involving wound healing, incision and drainage procedures, and readmission because of problems with wound healing. We conclude that perioperative antibiotic prophylaxis with cefonicid is useful for herniorrhaphy and certain types of breast surgery.     

Role of perioperative low dose vaginal oestrogens in improving the outcomes of pelvic organ prolapse surgery

Pelvic organ prolapse (POP) is the most common gynaecological disorder requiring surgical treatment in postmenopausal women. Surgical treatment of POP might include anterior or posterior vaginal repair, vaginal hysterectomy, vault fixation procedures like sacrocolpopexy and sacrospinous fixation. Complications of POP surgery include excessive bleeding, visceral injuries, postoperative wound infection, urinary tract infection (UTI), sexual dysfunction secondary to vaginal scarring and recurrence. Postmenopausal vaginal atrophy may increase the risk of visceral injuries due to thinning of vaginal wall and also increases the risk of surgical site wound infections due to alteration of vaginal flora and urinary tract infections (UTI). Use of vaginal low dose oestrogens to treat atrophy of the vagina may improve the subjective cure rates and minimise surgical site wound infections by altering the vaginal flora to premenopausal levels. To date there has not been any data on the outcomes of POP surgery when low dose vaginal oestrogens are used perioperatively. Hence we want to study the effectiveness of vaginal low dose oestrogen on the outcome of POP surgery in postmenopausal women.     

Role of perioperative low dose vaginal oestrogens in improving the outcomes of pelvic organ prolapse surgery

Pelvic organ prolapse (POP) is the most common gynaecological disorder requiring surgical treatment in postmenopausal women. Surgical treatment of POP might include anterior or posterior vaginal repair, vaginal hysterectomy, vault fixation procedures like sacrocolpopexy and sacrospinous fixation. Complications of POP surgery include excessive bleeding, visceral injuries, postoperative wound infection, urinary tract infection (UTI), sexual dysfunction secondary to vaginal scarring and recurrence. Postmenopausal vaginal atrophy may increase the risk of visceral injuries due to thinning of vaginal wall and also increases the risk of surgical site wound infections due to alteration of vaginal flora and urinary tract infections (UTI). Use of vaginal low dose oestrogens to treat atrophy of the vagina may improve the subjective cure rates and minimise surgical site wound infections by altering the vaginal flora to premenopausal levels. To date there has not been any data on the outcomes of POP surgery when low dose vaginal oestrogens are used perioperatively. Hence we want to study the effectiveness of vaginal low dose oestrogen on the outcome of POP surgery in postmenopausal women.     

Pseudomonas aeruginosa biofilms perturb wound resolution and antibiotic tolerance in diabetic mice

Diabetic patients are more susceptible to the development of chronic wounds than non-diabetics. The impaired healing properties of these wounds, which often develop debilitating bacterial infections, significantly increase the rate of lower extremity amputation in diabetic patients. We hypothesize that bacterial biofilms, or sessile communities of bacteria that reside in a complex matrix of exopolymeric material, contribute to the severity of diabetic wounds. To test this hypothesis, we developed an in vivo chronic wound, diabetic mouse model to determine the ability of the opportunistic pathogen, Pseudomonas aeruginosa, to cause biofilm-associated infections. Utilizing this model, we observed that diabetic mice with P. aeruginosa-infected chronic wounds displayed impaired bacterial clearing and wound closure in comparison with their non-diabetic littermates. While treating diabetic mice with insulin improved their overall health, it did not restore their ability to resolve P. aeruginosa wound infections or speed healing. In fact, the prevalence of biofilms and the tolerance of P. aeruginosa to gentamicin treatment increased when diabetic mice were treated with insulin. Insulin treatment was observed to directly affect the ability of P. aeruginosa to form biofilms in vitro. These data demonstrate that the chronically wounded diabetic mouse appears to be a useful model to study wound healing and biofilm infection dynamics, and suggest that the diabetic wound environment may promote the formation of biofilms. Further, this model provides for the elucidation of mechanistic factors, such as the ability of insulin to influence antimicrobial effectiveness, which may be relevant to the formation of biofilms in diabetic wounds.     

Wound microbiology and associated approaches to wound management

The majority of dermal wounds are colonized with aerobic and anaerobic microorganisms that originate predominantly from mucosal surfaces such as those of the oral cavity and gut. The role and significance of microorganisms in wound healing has been debated for many years. While some experts consider the microbial density to be critical in predicting wound healing and infection, others consider the types of microorganisms to be of greater importance. However, these and other factors such as microbial synergy, the host immune response, and the quality of tissue must be considered collectively in assessing the probability of infection. Debate also exists regarding the value of wound sampling, the types of wounds that should be sampled, and the sampling technique required to generate the most meaningful data. In the laboratory, consideration must be given to the relevance of culturing polymicrobial specimens, the value in identifying one or more microorganisms, and the microorganisms that should be assayed for antibiotic susceptibility. Although appropriate systemic antibiotics are essential for the treatment of deteriorating, clinically infected wounds, debate exists regarding the relevance and use of antibiotics (systemic or topical) and antiseptics (topical) in the treatment of nonhealing wounds that have no clinical signs of infection. In providing a detailed analysis of wound microbiology, together with current opinion and controversies regarding wound assessment and treatment, this review has attempted to capture and address microbiological aspects that are critical to the successful management of microorganisms in wounds.     

Infection Caused by Nocardia farcinica: Case Report and Review

 Nocardia farcinica is a rare Nocardia species causing localised and disseminated infections. A case of Nocardia farcinica infection is presented, and 52 cases previously reported in the literature are reviewed. The hosts usually had predisposing conditions (85%), and acquired the infection through the respiratory tract or skin; the infection then often spread to the brain, kidney, joints, bones and eyes. Pulmonary or pleural infections (43%), brain abscesses (30%) and wound infections (15%) which failed to respond to conventional antimicrobial therapy were the more frequent forms of infection. Nocardia farcinica was frequently isolated from pus (100% of samples), bronchial secretions (41%) and biopsy specimens (63%), but isolation from blood and urine, as in the case presented here, is rare. Antibiotic therapy was adequate in 61% of the patients in whom it was specified, the agents most frequently given being trimethoprim-sulfamethoxazole (54%), amikacin combined with imipenem (7%) and amoxicillin-clavulanate (7%). The high mortality (31%) can be attributed to the severe underlying diseases present, difficulties encountered in identifying the pathogen, inappropriate therapy and late initiation of therapy. Although an infrequent pathogen, Nocardia farcinica should be kept in mind as a cause of infection especially in immunosuppressed patients with indolent infections not responding to third-generation cephalosporins.