BACKGROUND: Propionibacterium acnes and P. granulosum are widely regarded as the aetiological agents of inflammatory acne. Their proliferation and metabolism are controlled using lengthy courses of oral and/or topical antibiotics. Despite numerous reports of skin colonization by antibiotic-resistant propionibacteria among acne patients, accurate prevalence data are available only for the U.K. OBJECTIVES: To determine the prevalence of skin colonization by antibiotic-resistant propionibacteria among acne patients and their contacts from six European centres. METHODS: Skin swabs were collected from 664 acne patients attending centres in the U.K., Spain, Italy, Greece, Sweden and Hungary. Phenotypes of antibiotic-resistant propionibacteria were determined by measuring the minimum inhibitory concentrations (MIC) of a panel of tetracycline and macrolide, lincosamide and streptogramin B (MLS) antibiotics. Resistance determinants were characterized by polymerase chain reaction (PCR) using primers specific for rRNA genes and erm(X), followed by nucleotide sequencing of the amplified DNA. RESULTS: Viable propionibacteria were recovered from 622 patients. A total of 515 representative antibiotic-resistant isolates and 71 susceptible isolates to act as control strains were characterized phenotypically. The prevalence of carriage of isolates resistant to at least one antibiotic was lowest in Hungary (51%) and highest in Spain (94%). Combined resistance to clindamycin and erythromycin was much more common (highest prevalence 91% in Spain) than resistance to the tetracyclines (highest prevalence 26.4% in the U.K.). No isolates resistant to tetracycline were detected in Italy, or in Hungary. Overall, there were strong correlations with prescribing patterns. Prevalence of resistant propionibacteria on the skin of untreated contacts of the patients varied from 41% in Hungary to 86% in Spain. Of the dermatologists, 25 of 39 were colonized with resistant propionibacteria, including all those who specialized in treating acne. None of 27 physicians working in other outpatient departments harboured resistant propionibacteria. CONCLUSIONS: The widespread use of topical formulations of erythromycin and clindamycin to treat acne has resulted in significant dissemination of cross-resistant strains of propionibacteria. Resistance rates to the orally administered tetracycline group of antibiotics were low, except in Sweden and the U.K. Resistant genotypes originally identified in the U.K. are distributed widely throughout Europe. Antibiotic-resistant propionibacteria should be considered transmissible between acne-prone individuals, and dermatologists should use stricter cross-infection control measures when assessing acne in the clinic.
The aim of this study was to determine antibiotic susceptibility of Propionibacterium acnes isolates from prostate. Prostate-derived P. acnes isolates (n = 24, Umeå & Örebro, Sweden, 2007-2010) and a panel of control strains (n = 25, Sweden) collected from skin and deep infections were assessed for resistance to penicillin G, piperacillin-tazobactam, imipenem, gentamicin, azithromycin, erythromycin, vancomycin, ciprofloxacin, moxifloxacin, tetracycline, tigecycline, fusidic acid, clindamycin, rifampicin, linezolid, daptomycin, trimethoprim-sulfamethoxazole, and metronidazole. In addition, the isolates were tested for inducible clindamycin resistance. All prostate derived P. acnes isolates displayed wild-type distribution of MIC-values, without evidence of acquired resistance. In the reference panel, 5 of 25 isolates had acquired macrolide resistance with cross-resistance to azithromycin, clindamycin, and erythromycin. In addition, one of these isolates was resistant to tetracycline.
The prevalence of antibiotic resistance and their genetic determinants in colonizing group B streptococci (GBS) sampled in a Swedish nationwide survey was examined. In five GBS isolates (1.3%), kanamycin/amikacin resistance and the presence of the aphA-3 gene was identified. Three of these isolates carried the aad-6 gene and were streptomycin-resistant. Screening with kanamycin and streptomycin 1,000-?g disks enabled a rapid and easy detection of these isolates. In all, 312/396 (79%) GBS were tetracycline-resistant and 95% of the examined isolates harbored the tetM gene. Among the 22 (5.5%) GBS resistant to erythromycin and/or clindamycin, the ermB gene was detected in nine isolates (41%) and erm(A/TR) in ten isolates (45%). A high level of erythromycin and clindamycin resistance with minimum inhibitory concentrations (MICs) >256?mg/L was found in four serotype V isolates that harbored ermB. The erythromycin/clindamycin resistance was distributed among all of the common serotypes Ia, Ib, II, III, IV, and V, but was not present in any of the 44 serotype III isolates associated to clonal complex 17. Screening for penicillin resistance with 1-?g oxacillin disks showed a homogenous population with a mean inhibition zone of 20?mm. A change in the present oxacillin breakpoints for GBS is suggested.
The primary aim of this study was to determine antimicrobial resistance in coagulase-negative staphylococci (CoNS) from healthy adults in the community. Healthy adults (n = 114) were swabbed on six body sites; both armpits, both knee pits and both sides of the groin. Species determination was performed using Matrix Assisted Laser Desorption Ionization - Time of Flight (MALDI-TOF) and susceptibility testing for 11 relevant antimicrobials was performed by the disc diffusion method and minimal inhibitory concentration gradient test. In total, 693 CoNS isolates were identified. Susceptibility testing was done on 386 isolates; one CoNS from each species found on each participant from the different body sites. The prevalence of antimicrobial resistance in the CoNS isolates were; erythromycin (24.6%), fusidic acid (19.9%), tetracycline (11.4%), clindamycin (7.8%), gentamicin (6.2%) and cefoxitin (4.1%). Multidrug resistance was observed in 5.2% of the isolates. Staphylococcus epidermidis and S. hominis were the first and second most prevalent species on all three body sites. We conclude that CoNS isolates from healthy adults in the community have a much lower prevalence of antimicrobial resistance than reported in nosocomial CoNS isolates. Still, we believe that levels of resistance in community CoNS should be monitored as the consumption of antimicrobials in primary care in Norway is increasing.
To our knowledge, there are no published papers detailing antisepsis for injection sites. In view of this, the efficacies of povidone-iodine (PVP-I) ethanol solution and chlorhexidine (CH) ethanol, the agents most commonly used for antisepsis of the operative field, were compared. Before and after the injection site was disinfected with either of these antiseptics, specimens of indigenous bacteria on the skin were collected by the cylinder scrub method, and the bacteria reduction rate and the reduction factor (RF) were determined to evaluate the efficacy of antisepsis. The bacteria reduction rate and RF value obtained for PVP-I ethanol were 95.1 +/- 11.2 and 2.1 +/- 0.9% and those for CH ethanol were 93.5 +/- 9.3 and 1.8 +/- 0.9%. Since there were individual differences in cell count before antisepsis, no significant difference was seen in bactericidal activity. However, slightly more favorable results were obtained with PVP-I ethanol. Although it is impossible to eradicate completely the indigenous microbes with currently available methods, it is considered important for the prevention of infection of the injection site to decrease bacterial counts as much as possible.
Bacterial contamination of platelet components (PCs) remains an important cause of transfusion-associated infectious risk. In 2004, Canadian Blood Services (CBS) implemented bacterial testing of PCs using the BacT/ALERT 3D system (bioMérieux). This system has been validated and implemented and continuous monitoring of culture rates allows gathering of data regarding true and false positives as well as false negatives.
National data gathered between March 2004 and October 2010 from 12 CBS sites were analyzed to compare bacterial contamination rates across three platelet (PLT) preparation methods: apheresis, buffy coat, and PLT-rich plasma. Data were compared before and after implementation of protocol changes that may affect bacterial detection or contamination rates.
Initial positive rates among the three production methods were significantly different, with apheresis PCs being the highest. The rates of confirmed positives among production methods did not differ significantly (p = 0.668). Increasing sample testing volumes from 4 to 6 mL to 8 to 10 mL significantly increased the rate of initial positives, while confirmed positives increased from 0.64 to 1.63 per 10,000, approaching significance (p = 0.055). Changing the skin disinfection method from a two-step to a one-step protocol did not significantly alter the rate of confirmed positives. During the period of data analysis, eight false-negative cases were reported, with five implicated in adverse transfusion reactions.
Bacterial testing of PCs and implementation of improved protocols are incrementally effective in reducing the risk of transfusion of bacterially contaminated PLT concentrates; however, the continued occurrence of false-negative results means the risk has not been eliminated.
The bacterial flora of the forehead and back of Eskimo and Indian villagers in arctic Alaska was determined in midsummer and in winter (temperature -29 degrees to -46 degrees C). Specimens collected by the wet swab method were transported overnight, chilled, to Seattle in buffered diluent with Triton X-100. Control tests showed good survival of principal skin organisms with moderate or large initial populations and a disproportionately greater loss with an initial sparse population. Results of these studies are compared with earlier studies of the forehead flora of a Seattle urban population. On most Alaskan subjects Propionibacterium acnes was more abundant than staphylococci on both sites and both organisms had greater population densities on the forehead than on the back. Population densities for P. acnes varied from none detected to more than 10(6) per cm2 on the forehead and 10(5) per cm2 on the back. For coagulase-negative staphylococci the range was from none detected to more than 10(5) per cm2 on the forehead and the back. The proportion of subjects with relatively abundant or relatively sparse populations of P. acnes and of staphylococci did not change seasonally. Of 51 staphylococcal isolates, 65% were S. epidermidis, 22% S. capitis, and 10% S. hominis. P. saccharolyticus was found on a minority of subjects on both sites. The kinds of organisms found on the forehead and their variable individual population densities were essentially the same on the Alaskan villagers and the Seattle subjects.
From: Fortuine, Robert et al. 1993. The Health of the Inuit of North America: A Bibliography from the Earliest Times through 1990. University of Alaska Anchorage. Citation number 1867.
The microbial flora and counting were studied in split porcine skin. The results indicated that the routine method for the preparation of porcine heterograft could not reduce the indigenous flora in the dermal appendages efficiently. The indigenous flora of porcine skin consists of not only Gram positive cocci and Gram negative rods, fungus are the another predominant ones, the later may contribute to the frequent complication of fungal infection and the early rejection of porcine heterograft. A tincture of iodine compound was prepared and used for the purpose of disinfection, a better result was obtained.
Some bacteria have a natural tendency to adhere to available surfaces and to form biofilms. Biofilms have been demonstrated on right heart flow-directed catheters, endocardial pacemaker leads, urinary catheters, and other medical devices. In this study, we examined arterial and central venous catheters that had been in place in ICU patients between 1 and 14 days for the presence of bacterial biofilms by scanning electron microscopy, transmission electron microscopy, and a special scraping/sonication bacterial recovery technique. The data taken from these processes were compared with skin entry site swabs and blood cultures and correlated with patient data on infection, bacterial colonization, and antibiotic use.
Extensive biofilm formation was demonstrated by scanning electron microscopy on all 42 arterial and 26 central venous catheters. Bacteria were seen within the biofilms on 69% (29/42) of the arterial and 88% (23/26) of the central venous catheters. These two direct methods for the detection of biofilm bacteria on the catheter surfaces demonstrated the presence of adherent organisms on 81% of devices examined. Some catheters that had been in place for only 1 day were colonized by bacterial biofilms. Biofilm scraped from catheter surfaces and dispersed by mixing and sonication yielded cultures (32% of catheters) of predominantly skin bacteria. In a few instances, the recovery of bacteria from biofilms on vascular catheters coincided with positive cultures from skin entry site swabs and/or from the blood of the patient, but there was no significant correlation between bacterial recovery from the catheter surface, entry site, and/or patients' blood.
Direct microscopic examination of 68 vascular catheters that had been in place 1 to 14 days showed that most (81%) were colonized by bacteria growing in slime-enclosed biofilms. In many cases, this colonization of catheter surfaces could be confirmed by special biofilm culture recovery methods. Although the clinical importance of bacterial biofilms on catheter surfaces is speculative, their presence and potential to serve as a nidus for infection and bacteremia in critically ill immunocompromised hosts are cause for concern.