Wound Swab Culture Research Articles

The prevalence of fungal infections in a level I Iranian burn hospital

Background: With significant increase in incidence of fungal infections in burn victims, determination of patternof fungal infections and colonization is required to allow medical staff to begin proper empirical antibiotic therapyin early stages of septic episodes. Objective: To determine the current infection profile (especially fungal profile) of burn wounds in a level I burncare center in Tehran. Methods: A cross-sectional survey was conducted from January 2008 to September 2009 on burn wound patientsadmitted in Shahid Motahari Burn Hospital, Tehran, Iran. Wound swab cultures and tissue specimens from 869patients (634 male and 235 female) out 4083 were taken and cultured in Sabouraud dextrose agar. The fungalorganisms were then identified with macroscopic and microscopic structures. Results: The incidence of fungal infection (not colonization) among the patients of this study was 13%.Candida albicans was identified as the dominant fungal agent (45%) followed by Aspergillus fumigatus (35%),Penicillium (8%), Aspergillus niger (5%), and other fungal organisms (7%). Conclusion: With such high mortality rate and an increasing incidence of fungal wound infections, fungalinfections should be a top infectious complication of burn patients and should be managed immediately andaggressively. Keywords: Burn wound, Candida albicans, colonization, fungal infection, incidence

5 year analysis of bacteriology culture in a tropical burns ICU

Introduction Infection is a major cause of morbidity and mortality in burns patients. Methodology A retrospective review of all 94 patients admitted to a regional burns ICU from 2004 to 2009 was performed. All the patients’ data and records of all culture isolates from a computerized hospital wide database were studied. Epidemiology of the patients, bacteriology information including yield and correlation of bacteremia with positive cultures from other sites were examined. In addition, the relationship between burns excision surgeries to bacteremia was analyzed. Results 402 tissue cultures, 238 wound swab cultures, 269 endotracheal cultures, 125 urine cultures, 236 tip of monitoring line cultures and 474 blood cultures were studied. Acinetobacter baumannii was the most prevalent bacteria for all culture methods. Within 24 h of bacteremia, the tissue, line tips, endotracheal and wound swab cultures had yielded very similar pathogens (>70% of the time) to those from the blood stream. Furthermore 60% of all bacteremic episodes occur within 48 h of the surgery. Conclusion In ICUs where multidrug resistant pathogens are endemic, the choice of appropriate antimicrobial empiric cover should be guided by the intensity of colonization with these organisms as indicated by the cultures from various sites.

A Case Report: Efficiency of Microbial Cellulose Dressing in Partial Thickness Burn Wounds

Microbial cellulose is a natural polymer that can hold an amount of water without any disconformities as a result it considered to be a wound dressing material. We report a case of 28 percent total body surface area partial thickness flame burn approximately 4.5 % superficial partial thickness burns on anterior face and 23.5 % mixed between superficial and deep partial thickness burns on both upper arms and anterior trunk. Microbial cellulose dressing “Nanocell” (thai nanocellulose Co.LTD, Bangkok, Thailand) was applied onto the face wound for once time without any other dressing changed after this application. Progress of healing until full epithelialization on face was observed within 2 weeks. During the treatment, the patient did not show any irritation or allergic reaction to this new dressing and there was no evidence of bacteria presence after burn wound swab culture. This innovative material will be an alternative dressing in superficial partial thickness burn wounds.

Efficiency of Microbial Cellulose Dressing in Partial-Thickness Burn Wounds

Microbial cellulose is a natural polymer that can hold a quantity of water without any disconformities. Therefore, it is proposed for use as wound dressing material. We report a case of 28% total body surface area partial-thickness flame burn: approximately 4.5% superficial partial-thickness burns on anterior face and 23.5% combined superficial and deep partial-thickness burns on both upper arms and anterior trunk. A microbial cellulose dressing, Nanocell (Thai Nano Cellulose Co Ltd, Bangkok, Thailand), was applied to the face wound only once, without any further dressing change. Progress of healing, until full epithelialization on the face, was observed for 2 weeks. During the treatment period, the patient did not show any irritation or allergic reaction to this new dressing, and wound swab culture showed no evidence of bacteria presence. This innovative material can be an alternative dressing for superficial partial-thickness burn wounds.

Collagen dressing versus conventional dressings in burn and chronic wounds: A retrospective study

Objective:Biological dressings like collagen are impermeable to bacteria, and create the most physiological interface between the wound surface and the environment. Collagen dressings have other advantages over conventional dressings in terms of ease of application and being natural, non-immunogenic, non-pyrogenic, hypo-allergenic, and pain-free. This study aims to compare the efficacy of collagen dressing in treating burn and chronic wounds with that of conventional dressing materials.Materials and Methods:The records of 120 patients with chronic wounds of varied aetiologies and with mean age 43.7 years were collected and analyzed. The patients had been treated either with collagen or other conventional dressing materials including silver sulfadiazine, nadifloxacin, povidone iodine, or honey (traditional dressing material). Patients with co-morbidities that could grossly affect the wound healing like uncontrolled diabetes mellitus, chronic liver or renal disease, or major nutritional deprivation were not included. For the purpose of comparison the patients were divided into two groups; ‘Collagen group’ and ‘Conventional group’, each having 60 patients. For assessment the wound characteristics (size, edge, floor, slough, granulation tissue, and wound swab or pus culture sensitivity results) were recorded. With start of treatment, appearance of granulation tissue, completeness of healing, need for skin grafting, and patients’ satisfaction was noted for each patient in both groups.Results:With two weeks of treatment, 60% of the ‘collagen group’ wounds and only 42% of the ‘conventional group’ wounds were sterile (P=0.03). Healthy granulation tissue appeared earlier over collagen-dressed wounds than over conventionally treated wounds (P=0.03). After eight weeks, 52 (87%) of ‘collagen group’ wounds and 48 (80%) of ‘conventional group’ wounds were >75% healed (P=0.21). Eight patients in the ‘collagen group’ and 12 in the ‘conventional group’ needed partial split-skin grafting (P=0.04). Collagen-treated patients enjoyed early and more subjective mobility.Conclusion:No significant better results in terms of completeness of healing of burn and chronic wounds between collagen dressing and conventional dressing were found. Collagen dressing, however, may avoid the need of skin grafting, and provides additional advantage of patients’ compliance and comfort.

Assessing bacterial burden in wounds: comparing clinical observation and wound swabs

A randomised controlled trial (RCT) was conducted to compare the efficacy of nanocrystalline silver and cadexomer iodine dressings in healing chronic lower leg ulcers. The relationships between wound swab culture results and nurses' clinical assessments of critical colonisation, and between bacterial burden and healing rate, were also examined. There were 281 individuals with leg ulcers recruited. The bacterial burden of wounds was assessed using semi-quantitative wound swabs collected at baseline and intervals during the study. The study found no relationship between the nurses' clinical assessments and bacterial burden as identified from wound swabs in the wounds. A significant difference in wound healing was found with the use of nanocrystalline silver as compared to cadexomer iodine in the first 2 weeks of treatment when nil or low levels of leukocytes, gram positive bacilli, gram positive cocci or gram negative cocci were reported. This study has raised a number of questions regarding the need for further investigation into methods of assessing wound bacterial burden as well as the impact of wound biofilms on wound assessment and treatment.

Bacteriological pattern of wound swab isolates in patients with chronic leg ulcer

PURPOSE: To determine the pattern of bacterial pathogens and their antibiotic sensitivity profile in patients with infected chronic leg ulceration. METHODS: Sixty swab specimens obtained from chronic leg ulcer (CLU) patients were cultured aerobically and the antibiotic sensitivity pattern of the recovered organisms determined by the modified Kirby- Bauer disc-diffusion method. RESULTS: 47 (78.3%) of the ulcers were infected out of which 39 (83.0%) were culture positive. Most of the culture positive ulcers were on the distal third of the leg. The isolated bacteria from the wounds were Pseudomonas aeruginosa (33%), Staphylococcus aureus (24%), Proteus spp (15%), Klebsiella spp (13%), Citrobacter spp (13%) and Escherichia coli (2%). None of the patient without clinical evidence of wound infection had bacterial positive wound swab culture. All isolates were sensitive to third generation cephalosporin and floroquinolones but majority were resistant to ampicillin. CONCLUSION: Pseudomonas aeruginosa, Staphylococcus aureus. Proteus spp, Klebsiella spp, Citrobacter spp and Escherichia coli sensitive to third generation cephalosporin and floroquinolones have been recovered from 78% of patients with chronic leg ulcers in a tertiary health facility in Nigeria. Keywords: Bacteriology; Chronic leg ulcer; Wound swab

A comparative study to evaluate the effect of honey dressing and silver sulfadiazene dressing on wound healing in burn patients

ABSTRACTTo compare the effect of honey dressing and silver-sulfadiazene (SSD) dressing on wound healing in burn patients. Patients (n=78) of both sexes, with age group between 10 and 50 years and with first and second degree of burn of less than 50% of TBSA (Total body surface area) were included in the study, over a period of 2 years (2006-08). After stabilization, patients were randomly attributed into two groups: ‘honey group’ and ‘SSD group’. Time elapsed since burn was recorded. After washing with normal saline, undiluted pure honey was applied over the wounds of patients in the honey group (n=37) and SSD cream over the wounds of patients in SSD group (n=41), everyday. Wound was dressed with sterile gauze, cotton pads and bandaged. Status of the wound was assessed every third and seventh day and on the day of completion of study. Patients were followed up every fortnight till epithelialization. The bacteriological examination of the wound was done every seventh day. The mean age for case (honey group) and control (SSD group) was 34.5 years and 28.5 years, respectively. Wound swab culture was positive in 29 out of 36 patients who came within 8 hours of burn and in all patients who came after 24 hours. The average duration of healing in patients treated with honey and SSD dressing at any time of admission was 18.16 and 32.68 days, respectively. Wound of all those patients (100%) who reported within 1 hour became sterile with honey dressing in less than 7 days while none with SSD. All of the wounds became sterile in less than 21 days with honey, while tthis was so in only 36.5% with SSD treated wounds. The honey group included 33 patients reported within 24 hour of injury, and 26 out of them had complete outcome at 2 months of follow-up, while numbers for the SSD group were 32 and 12. Complete outcome for any admission point of time after 2 months was noted in 81% and 37% of patients in the honey group and the SSD group. Honey dressing improves wound healing, makes the wound sterile in lesser time, has a better outcome in terms of prevention of hypertrophic scarring and post-burn contractures, and decreases the need of debridement irrespective of time of admission, when compared to SSD dressing.

A comparative study to evaluate the effect of honey dressing and silver sulfadiazene dressing on wound healing in burn patients.

To compare the effect of honey dressing and silver-sulfadiazene (SSD) dressing on wound healing in burn patients. Patients (n=78) of both sexes, with age group between 10 and 50 years and with first and second degree of burn of less than 50% of TBSA (Total body surface area) were included in the study, over a period of 2 years (2006-08). After stabilization, patients were randomly attributed into two groups: ‘honey group’ and ‘SSD group’. Time elapsed since burn was recorded. After washing with normal saline, undiluted pure honey was applied over the wounds of patients in the honey group (n=37) and SSD cream over the wounds of patients in SSD group (n=41), everyday. Wound was dressed with sterile gauze, cotton pads and bandaged. Status of the wound was assessed every third and seventh day and on the day of completion of study. Patients were followed up every fortnight till epithelialization. The bacteriological examination of the wound was done every seventh day. The mean age for case (honey group) and control (SSD group) was 34.5 years and 28.5 years, respectively. Wound swab culture was positive in 29 out of 36 patients who came within 8 hours of burn and in all patients who came after 24 hours. The average duration of healing in patients treated with honey and SSD dressing at any time of admission was 18.16 and 32.68 days, respectively. Wound of all those patients (100%) who reported within 1 hour became sterile with honey dressing in less than 7 days while none with SSD. All of the wounds became sterile in less than 21 days with honey, while tthis was so in only 36.5% with SSD treated wounds. The honey group included 33 patients reported within 24 hour of injury, and 26 out of them had complete outcome at 2 months of follow-up, while numbers for the SSD group were 32 and 12. Complete outcome for any admission point of time after 2 months was noted in 81% and 37% of patients in the honey group and the SSD group. Honey dressing improves wound healing, makes the wound sterile in lesser time, has a better outcome in terms of prevention of hypertrophic scarring and post-burn contractures, and decreases the need of debridement irrespective of time of admission, when compared to SSD dressing.

Necrotizing fasciitis with toxic shock syndrome in a child: a case report and review of literature

IntroductionNecrotizing fasciitis was described as early as the fifth century BC. It showed an increased incidence worldwide in the past several years.Case presentationAn 8-year-old Arabian boy was referred for admission as a case of cellulitis of the left thigh. Ten days prior to admission he had a cat scratch to his left thigh and the parents did not seek medical advice at that time. The child was again examined by orthopedic surgeon and a diagnosis of cellulites was made at that time.Physical examination on admission revealed a very toxic appearing weak child with cold extremities and poor peripheral perfusion.Examination of the left thigh revealed extensive swelling, induration and edema with dusky skin, blistering and bleb formation, in addition to an area of gangrenous skin. Laboratory investigation revealed white blood cell count of 22,400 × 109 with toxic granulation on peripheral blood smear.The child was admitted to the pediatric intensive care unit and dopamine and dobutamine infusions were started after volume expansion. Penicillin and clindamycin also were started in addition to multiple transfusions of fresh frozen plasma. Surgical debridement of all necrotic tissues and drainage of involved fascia planes via extensive fasciotomy were done for our patient after stabilization of his vital signs and improvement of his general condition.Blood cultures grew group A streptococcus, as did wound swab culture.The child showed great improvements in his clinical condition after the 3rd day of antibiotics and supportive treatment and the wound healed normally and antibiotics were administered for 21 days.ConclusionNecrotizing fasciitis in children is a frequently misdiagnosed condition; early identification of the necrotizing process can improve the outcome of this life-threatening disease. Surgical debridement and antibiotics were the most important therapeutic measures.

Observational study of bone-anchored hearing aid infection rates using different post-operative dressings

Avoidance of infection at the implant site is a crucial element to the success of bone-anchored hearing aid (BAHA) implantation. However, little evidence exists to suggest the best post-operative wound dressing to use. We report our experience with 160 consecutive BAHA patients, using four types of post-operative BAHA wound dressing (Tri-adcortyl, Mepitel, Allevyn, and Acticoat 7 with Allevyn). Patients were reviewed at week one and week two post-operatively. Infection was defined as a positive wound swab culture or evidence of cellulitis at the BAHA site. Post-operative BAHA infection rates were 16 per cent, 50 per cent, 10 per cent and 5 per cent, for each of the four dressings respectively, and the mean number of additional visits to wound care clinic were 1.5, 3.7, one and 0.4, respectively. Acticoat 7 with Allevyn produced the lowest infection rate and thus became the dressing of choice for our BAHA programme.

Bacterial and fungal colonization of burn wounds

A prospective study of fungal and bacterial flora of burn wounds was carried out from February 2004 to February 2005 at the Burns Unit of Hospital Regional da Asa Norte, Brasília, Brazil. During the period of the study, 203 patients were treated at the Burns Unit. Wound swab cultures were assessed at weekly intervals for four weeks. Three hundred and fifty four sampling procedures (surface swabs) were performed from the burn wounds. The study revealed that bacterial colonization reached 86.6% within the first week. Although the gram-negative organisms, as a group, were more predominant, Staphylococcus aureus (28.4%) was the most prevalent organism in the first week. It was however surpassed by Pseudomonas aeruginosa form third week onwards. For S. aureus and P. aeruginosa vancomycin and polymyxin were found to be the most effective drugs. Most of the isolates showed high level resistance to antimicrobial agents. Fungi were found to colonize the burn wound late during the second week postburn, with a peak incidence during the third and fourth weeks. Species identification of fungi revealed that Candida tropicalis was the most predominant, followed by Candida parapsilosis. It is crucial for every burn institution to determine the specific pattern of burn wound microbial colonization, the time-related changes in the dominant flora, and the antimicrobial sensitivity profiles. This would enable early treatment of imminent septic episodes with proper empirical systemic antibiotics, without waiting for culture results, thus improving the overall infection-related morbidity and mortality.

An evaluation of the role of systemic antibiotic prophylaxis in the control of burn wound infection at the Lagos University Teaching Hospital

A prospective study was carried out on 61 patients to evaluate the role of systemic antibiotic prophylaxis in the control of burn wound infection. The patients were randomised into three groups: group 1 ( n=21) received ampicillin and cloxacillin; group 2 ( n=20) received erythromycin and genticin and a control group ( n=20) received no systemic chemo prophylaxis. The burn wounds were similarly managed. Wound colonisation was determined from surface wound swab cultures and wound infection was determined from wound biopsy cultures and histopathology. The colonisation time (days) for the groups was 2.90±0.92, 3.15±0.77 and 3.05±0.83 for groups 1 and 2 and the control, respectively. The commonest organism isolated from contaminated wounds was Staphylococcus aureus. Wound infection was established in 5.70±1.70, 5.75±1.62 and 5.6±1.90 days for group 1, group 2 and the control group, respectively. There was no significant difference between wound infection time of control and group 1 nor was there such difference between the control and group 2 ( P>0.05). The commonest organism infecting burn wounds in all the groups was Pseudomonas aeruginosa followed by S. aureus. There was however a significant difference between the treatment groups and the control ( P<0.05) with regard to the percentage of infected wounds that grew P. aeruginosa, compared to those that grew S. aureus. It was concluded that systemic antibiotic prophylaxis is of no value in controlling burn wound sepsis, and might even favour the growth of P. aeruginosa in the burn wounds.

Fever and a Rat Bite

269 A70-year-old previously healthy man presented to the emergency department with a three-day history of fever. Two weeks before, while working in the kitchen of his restaurant, he captured a rat. The rat bit him on his right thumb, prompting the man to kill the rat and dispose of it in the garbage. He saw his family physician, who gave him a topical antibiotic ointment and a tetanus booster. The wound healed and the patient felt well until 10 days later when he developed fever, chills and sweats. At the same time, his thumb became painful, swollen and erythematous. The wound dehisced spontaneously. He returned to his family physician, who prescribed oral cloxacillin and referred him to the emergency department. Upon arrival at the emergency department, his temperature was 39.1°C and his oxygen saturation was 90% on room air. Blood and wound swab cultures were obtained. The patient was given a second tetanus booster and a consultation with the infectious diseases service was requested. The patient was from China and had lived in Canada since 1996. He had not travelled outside Canada since his arrival. His vaccination history was unknown. There was no history of arthralgias, myalgias or rash. On physical examination by the infectious disease service, his blood pressure was 110/80 mmHg, his heart rate was 70 beats/min and regular, and his temperature was 36.7°C. His oxygen saturation was 97% on room air. There was no cervical adenopathy and his conjunctiva were normal. His neck was supple. Cardiovascular and abdominal examinations were normal. Auscultation of his chest revealed bibasilar inspiratory crackles. There was no rash, petechiae, jaundice or clubbing. His right thumb was swollen and erythematous to the base. There was a superficial puncture wound on the ventromedial aspect of his thumb (Figure 1). There was no drainage. His thumb was tender and indurated. There was also evidence of lymphangitis on the dorsal aspect of his right forearm. Initial laboratory investigations revealed a white blood cell count of 9.5×109/L, and normal electrolyte, renal and liver profiles. Two sets of blood cultures were negative. A Gram stain of the sample from the wound showed Gramnegative bacilli on microscopy, but the culture was negative. Radiographs of his chest and hand were normal. What is your diagnosis and how would you treat this patient?

Étude de la colonisation par Staphylococcus aureus résistant à la méticilline dans des services de soins de suite

Purpose. – Prevalence of methicillin-resistant Staphylococcus aureus is high in the Poitiers teaching hosiptal, particularly in the intermediate care facilities. We performed a survey of methicillin-resistant Staphylococcus aureus colonization in the intermediate care facilities and 265 patients were included. Methods. – Nasal, cutaneous and wound swab cultures were done at the time of admission and at the time of the patients’ departure. A decolonization procedure of methicillin-resistant Staphylococcus aureus carriers was performed using nasal application of fusidic acid and different soaps for the skin. At entry, 17.7% of patients were methicillin-resistant Staphylococcus aureus carriers (of at least one location). At departure, 30.4% were methicillin-resistant Staphylococcus aureus carriers. Among methicillin-resistant Staphylococcus aureus non-carriers at entry, 24.3% became methicillin-resistant Staphylococcus aureus carriers. Results. – The principal risk factor of carriage was the initial presence of a wound (RR = 3.6). The incidence rate of methicillin-resistant Staphylococcus aureus infection among the 265 patients included was 3%. Conclusion. – The systematic screening of patients at the time of admission is expensive and isolation technically hard to manage in the intermediate care facilities. The risk factor we found in this study allow us to propose a ‘light’ screening limited to patients with wounds.

Herpes simplex virus type 2 infection in a 5-year-old boy presenting with recurrent chest wall vesicles and a possible history of herpes encephalitis

A 5-year-old hyperkinetic but otherwise healthy child presented with recurrent irritable vesicles and erosions of the anterior chest wall; they have been apparent since the age of 15 months. Wound swab cultures yielded herpes simplex virus type-2 (HSV-2) and Western blot serology showed past exposure to both HSV-1 and HSV-2. Skin biopsy results further supported a herpes virus infection. Magnetic resonance imaging of the brain showed right temporal lobe atrophy. An evaluation showed no evidence of sexual abuse in the patient but a Western blot assay of the mother's serum for HSV-2 was positive, while the father's was negative. In view of the diagnosis of HSV-2 infection in such a young patient, the possible routes of transmission and the time of acquisition of infection were explored. We believe the most likely route of infection in this child was postnatal, through intimate contact with the mother.

Topical phenytoin in the treatment of split-thickness skin autograft donor sites: a comparative study with polyurethane membrane drape and conventional dressing

The effectiveness of topical phenytoin as a wound healing agent was compared with that of OpSite® (Smith & Nephew) and a conventional topical antibiotic dressing (Soframycin®, Roussel) in a controlled study of 60 patients with partial-thickness skin autograft donor sites on the lower extremities. Mean time to complete healing (complete epithelialization) was 6.2 ± 1.6 days in the phenytoin-treated group (30 patients), compared to 8.6±2.2 days with OpSite (15 patients), and 12.6±3.4 days in the 15 Soframycin-treated patients. The differences between the treatment groups were significant at P < 0.001. Mean pain scores were also lower in the phenytoin-treated group, 0.40±0.55 vs. 0.66±0.60 with OpSite ( P < 0.05) and 1.4±0.50 with the conventional dressing ( P < 0.001). Both phenytoin and OpSite were superior to the Soframycin dressing with respect to bacterial contamination and wound infection as measured by Gram stains of wound smears, swab and aspirate (OpSite) cultures, and clinical assessments ( P < 0.001) carried out on the fifth day of treatment. No local or systemic adverse effects of the three agents used were noted. Phenytoin appears to be an effective, low-cost and safe method for the treatment of partial-thickness skin graft donor sites, comparing very favourably with, and in some aspects superior to, occlusive dressings. Further clinical use and evaluation of topical phenytoin are merited.

Bacterial flora of burn wounds in Lagos, Nigeria: A prospective study

A prospective study of burn wound sepsis was carried out on 31 consecutive patients with fresh burns. Wound swab cultures were assessed at weekly intervals for 5 weeks. The study revealed that while 96.7 per cent of burn wounds were sterile on admission, bacterial colonization reached 80.6 per cent within the first week after admission. Although the Gram-negative organisms, as a group, were more predominant, Staph. aureus (38.2 per cent) was the most prevalent organism in the first week. It was however surpassed by Pseud. aeruginosa from the second week onwards. Anaerobes were conspicuous by their absence. Similarly, β-haemolytic streptococcus was not isolated from any patient. Proteus mirabilis was unusually preponderant, forming 19.4 per cent of all isolates. The antibiotic senstivity pattern showed resistance of most of the organisms to ampicillin. Only 15 per cent of staphylococci were sensitive to cloxacillin. Most of the organisms cultured (93.5 per cent) were sensitive to ceftazidime.

THE MICROBIOLOGICAL SWAB SAMPLER ‐ A QUANTITATIVE EXPERIMENTAL INVESTIGATION

The aim of the investigation was to give an in vitro experimental account of the commonly used cotton swab as a sampler for quantitative determination of bacteria in operation wounds. The transfer of staphylococci with the swab from an inoculated to a non-inoculated agar culture plate was used as a model, and three different ways of swab handling were tested. A direct transfer of 19 per cent staphlococci from the inoculated to the non-inoculated plate was found. When the swab was rinsed in a small volume of saline and the rinsing fluid was plated, 39 per cent were transfered. When the swab was kept in a Stuart transport medium, as is the usual procedure in clinical practice, only 4 per cent were transfered. Quantitative wound swab cultures depend on a thorough sampling of the wound and an efficient recovery of bacteria from the swab. It is concluded that the use of a Stuart transport medium would appear to hamper quantitative determination, and a rinsing procedure should be preferred.