Flucloxacillin in the treatment of atopic dermatitis

Although colonization of atopic dermatitis by Staphylococcus aureus is universal and bacterial infection is common, it is not known whether antibiotic therapy is helpful in eczematous children who do not have any signs suggestive of bacterial infection. Fifty children aged 1-16 years with atopic dermatitis took part in a randomized double-blind placebo-controlled study of 4 weeks treatment with oral flucloxacillin, with an 8-week follow-up period. The change in the mean of the log10 of the counts/cm2 of S. aureus after 4 weeks of treatment was significantly different for patients receiving treatment, compared with the change for those receiving the placebo (P = 0.008). However, the difference in the change at 14 days after stopping treatment was not significant (P = 0.32). Methicillin-resistant strains of S. aureus were cultured from five children during or after treatment. Flucloxacillin did not improve the symptoms or clinical appearance of atopic dermatitis and only temporarily changed skin colonization by S. aureus.     

In vitro evaluation of activities of nitazoxanide and tizoxanide against anaerobes and aerobic organisms

The antibacterial activities of nitazoxanide and its main metabolite, tizoxanide, were tested against a broad range of bacteria, including anaerobes. Metronidazole, amoxicillin, amoxicillin-clavulanic acid, piperacillin, cefoxitin, imipenem, and clindamycin were used as positive controls. MICs were determined by reference agar dilution methods. The 241 anaerobes were all inhibited by nitazoxanide, with the MICs at which 90% of isolates are inhibited (MIC90S) being between 0.06 and 4 mg/liter with the exception of those for Propionibacterium species, for which the MIC90 was 16 mg/liter. The MIC90s of nitazoxanide were 0.5 mg/liter for the Bacteroides fragilis group (80 strains), 0.06 mg/liter for Clostridium difficile (21 strains), and 0.5 mg/liter for Clostridium perfringens (16 strains). Metronidazole showed a level of activity comparable to that of nitazoxanide except against Bifidobacterium species, against which it was poorly active, and Propionibacterium species, which were resistant to metronidazole. The other antibiotics showed various levels of activity against anaerobes, with imipenem along with nitazoxanide being the most active agents tested. Tizoxanide was less effective than nitazoxanide except against the B. fragilis group, against which its activity was similar to that of nitazoxanide. Under aerobic conditions, nitazoxanide demonstrated poor activity against members of the family Enterobacteriacae and Pseudomonas, Staphylococcus, and Enterococcus species. The same results were obtained when culture was performed under anaerobic conditions with the notable exception of the results against Staphylococcus aureus. The MICs of nitazoxanide were in the range of 2 to 4 mg/liter for 34 clinical isolates of S. aureus, 12 of which were methicillin resistant, while tizoxanide was not effective.     

Anaerobes and fungi in chronic suppurative otitis media

Microbiology of 102 ears with chronic suppurative otitis media was studied for aerobes, anaerobes, and fungi. Forty-four percent were pure cultures, 33.3% were mixed, and 18.6% had no growth. Seventy-four percent were aerobes, 25% fungi, and only 0.9% anaerobes. Pseudomonas aeruginosa (22.5%) was the most common isolate, followed by Staphylococcus aureus and the Aspergillus species. The possible reasons for low yield of anaerobes and the pathogenic roles of anaerobes and fungi in chronic suppurative otitis media are discussed. It is advocated that in investigating pathogenic organisms in chronic suppurative otitis media, requests should include anaerobes and fungi.     

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 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.     

Efficacy of itraconazole in children with Trichophyton tonsurans tinea capitis

The microbiology of needle aspirates from 40 inflamed cervical lymph glands was studied for aerobic and anaerobic bacteria, fungi and mycobacteria. Forty-two bacterial, 11 mycobacterial and six fungal isolates were isolated. Aerobic bacteria only were recovered in 11 (27.5%), anaerobes alone in five (12.5%) and mixed aerobic and anaerobic bacteria in seven (17.5%). Mycobacterium sp. were recovered in 11 (27.5%) and fungi in six (15%). The recovery of anaerobes was associated with dental infection. Eighteen aerobic bacteria were isolated and the predominant ones were Staphylococcus aureus (eight isolates) and group A streptococci (four). Twenty-four anaerobic bacteria were recovered and the predominant ones were: Prevotella sp. (six), Peptostreptococcus sp. (five), Propionibacterium acnes (four) and Fusobacterium sp. (three). These findings demonstrate the role of anaerobic organisms in cervical lymphadenitis and the need to culture aspirated material from the glands for both aerobic and anaerobic microorganisms.     

Metronidazole. A therapeutic review and update

The nitroimidazole antibiotic metronidazole has a limited spectrum of activity that encompasses various protozoans and most Gram-negative and Gram-positive anaerobic bacteria. Metronidazole has activity against protozoans like Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis, for which the drug was first approved as an effective treatment. Anaerobic bacteria which are typically sensitive are primarily Gram-negative anaerobes belonging to the Bacteroides and Fusobacterium spp. Gram-positive anaerobes such as peptostreptococci and Clostridia spp. are likely to test sensitive to metronidazole, but resistant isolates are probably encountered with greater frequency than with the Gram-negative anaerobes. Gardnerella vaginalis is a pleomorphic Gram-variable bacterial bacillus that is also susceptible to metronidazole. Helicobacter pylori has been strongly associated with gastritis and duodenal ulcers. Classic regimens for eradicating this pathogen have included metronidazole, usually with acid suppression medication plus bismuth and amoxicillin. The activity of metronidazole against anaerobic bowel flora has been used for prophylaxis and treatment of patients with Crohn's disease who might develop an infectious complication. Treatment of Clostridium difficile-induced pseudomembraneous colitis has usually been with oral metronidazole or vancomycin, but the lower cost and similar efficacy of metronidazole, coupled with the increased concern about imprudent use of vancomycin leading to increased resistance in enterococci, have made metronidazole the preferred agent here. Metronidazole has played an important role in anaerobic-related infections. Advantages to using metronidazole are the percentage of sensitive Gram-negative anaerobes, its availability as oral and intravenous dosage forms, its rapid bacterial killing, its good tissue penetration, its considerably lower chance of inducing C. difficile colitis, and expense. Metronidazole has notable effectiveness in treating anaerobic brain abscesses. Metronidazole is a cost-effective agent due to its low acquisition cost, its pharmacokinetics and pharmacodynamics, an acceptable adverse effect profile, and its undiminished antimicrobial activity. While its role as part of a therapeutic regimen for treating mixed aerobic/anaerobic infections has been reduced by newer, more expensive combination therapies, these new combinations have not been shown to have any therapeutic advantage over metronidazole. Although the use of metronidazole on a global scale has been curtailed by newer agents for various infections, metronidazole still has a role for these and other therapeutic uses. Many clinicians still consider metronidazole to be the 'gold standard' antibiotic against which all other antibiotics with anaerobic activity should be compared.     

Preoperative diagnosis of Mycobacterium avium lymphadenitis in two immunocompetent children by polymerase chain reaction of gastric aspirates

BACKGROUND: Analysis of gastric aspirates is a routine procedure for detection of Mycobacterium tuberculosis in pediatric pulmonary tuberculosis. However, identification of nontuberculous mycobacteria in gastric aspirates of immunocompetent children is not thought to be clinically significant. METHODS: A PCR method was devised for the detection of M. avium in clinical specimens. The method is based on the amplification of a M. avium-specific DNA fragment present in the 3'-end of the repetitive element IS1245. Surgically removed lymphatic tissue was analyzed prospectively by microscopy, culture and PCR in 13 children admitted to our hospital with suspected mycobacterial lymphadenitis. In 4 of these children 1 to 4 gastric aspirates were obtained before surgical treatment and submitted to the same analysis. RESULTS: We report the detection of M. avium in the gastric aspirates of two children with cervical lymphadenitis before surgical intervention by a novel PCR method. The subsequently surgically removed lymph nodes were also positive by PCR and culture. In one child cultures of both sources grew M. avium. The isolates could be identified as the same strain by DNA fingerprinting. The PCR assay was almost twice as sensitive as culture in detecting M. avium. CONCLUSIONS: Our findings suggest the possibility for noninvasive diagnosis of cervical lymphadenitis caused by nontuberculous mycobacteria before surgery. In addition detection of M. avium in gastric aspirates without evidence of fistula formation provides new insights into the pathogenesis of mycobacterial infection and disease in immunocompetent children.     

Ceftezole, a new cephalosporin C derivative I. In vitro and in vivo antimicrobial activity

Ceftezole, a new cephalosporin antibiotic similar to cefazolin, has the following chemical structure: (6R,7R)-8-oxo-7[2-(1H-tetrazol-1-yl)acetamido]-3-[(1,3,4-thiadiazol-2-ylthio)methyl]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-carboxylic acid. Ceftezole was found to be a broad-spectrum antibiotic, active in vitro against many species of gram-positive and gram-negative bacteria except Pseudomonas aeruginosa, Serratia marcescens and Proteus vulgaris. The activity of ceftezole against clinical isolates of Escherichia coli and Klebsiella spp. appeared to be nearly equal to that of cefazolin and higher than those of cephaloridine and cephalothin. Cross-resistance was observed between ampicillin and cephaloridine, but not between ampicillin and ceftezole, in susceptibility tests on clinical isolates of P. mirabilis. The in vitro activity was little affected by the inoculum size, the presence of human serum or the test medium. Ceftezole exhibited apparent bactericidal activity at the concentrations above the minimum inhibitory concentration (MIC) against both S. aureus and E. coli. The development in vitro of resistance by S. aureus 209p and E. coli NIHJ to ceftezole after 16 transfers was similar to or somewhat slower than that to other drugs tested. Ceftezole was relatively stable in nutrient broth and minimally degraded in the serum or tissue homogenates of rats. Ceftezole, in a single subcutaneous administration, exhibited somewhat less efficacy in mice against intraperitoneal infections with Streptococcus pyogenes, S. pneumoniae, E. coli, K. pneumoniae or P. mirabilis than either cephaloridine or cefazolin. However, ceftezole exhibited efficacy similar to that of cephaloridine or cefazolin when administered in three doses. Furthermore, ceftezole was as effective as cefazolin in the treatment of experimental abscesses in mice caused by subcutaneous inoculation with S. aureus.     

Clinical and bacteriological studies on panipenem/betamipron in pediatrics. Kanagawa Research Group for Infectious Diseases of Children

Following its introduction into the market, PAPM/BP (panipenem/betamipron) was clinically studied in 188 evaluable cases out of 207 cases primarily of respiratory infectious diseases treated at the pediatric departments of 15 hospitals. In the clinical evaluation, the drug proved effective in three of three cases of sepsis; three of three cases of suppurative meningitis; nine of ten cases of laryngopharyngitis, six of seven cases of tonsillitis, 56 of 63 cases of acute bronchitis, 90 of 98 cases of pneumonia, and one of one case of phyothorax, all of which are respiratory infectious diseases; one of one case of secondary infection of a chronic respiratory disease; and two of two cases of lymphadenitis, which is a disease of the soft dermal structure. The overall efficacy rate was 91.0% (171/188 cases). In the bacteriological study, Gram-positive bacteria were eliminated in five of five strains of S. aureus, 30 of 31 strains of S. pneumoniae (96.8%), and three of three strains of S. pyogenes. Gramnegative bacteria were eliminated in 15 of 17 strains of H. influenzae (88.2%), three of four strains of M. catarrhalis, and two of two strains of K. pneumoniae. The overall elimination rate was 92.1% (70/76 strains). In the 23 strains of S. pneumoniae that were examined, penicillin-resistant strains accounted for 56.5%, showing an elimination rate of 100%. No serious adverse effects were observed, and the incidence of adverse effects was 1.45%. As for abnormalities in laboratory tests, levels of GOT and GPT increased in eight cases (3.88%), LDH increased in one case (0.48%), and neutropenia occurred in one case (0.51%). These results suggest that PAMP/BP could be considered the first choice in the treatment of infectious diseases in pediatrics, due to its effectiveness and high level of safety.     

Incidence of nasal carriers of Staphylococcus aureus in and outside hospital environment and antibiotic sensitivity of isolated staphylococcus strains

This study was carried out on 100 nasal swabs collected from medical personnel (nurses and doctors) and patients inside hospital environment and also from 50 individuals outside hospital. The swabs were inoculated on different culture media for isolation of /staphylococci which were further identified as S. aureus either by classic bacteriologic methods or by one of rapid screening test of S. aureus. The isolated strains were tested for antibiotic sensitivity to some of B-Lactam antibiotics and to other antibiotics. The results showed that significantly higher percentage of coagulase + ve Staph. were isolated from newborn nursery (90%), operating theatre (71.4%) and hemodialysis unit (60%) than those isolated from intensive care unit, cancer chemotherapy, surgery, chest, internal medicine departments (25%, 26.6%, 31.2%, 33.3%, 50%) respectively. It also showed significant difference in isolation rate between persons at the hospital (patients, doctors and nurses) 44% and controls (normal population) 26%. Most isolates of coagulase + ve Staph. were resistant to penicillin G (93.2%), Streptomycin (77.3%), tetracycline (61.4%) and sensitive to cefamandole (95.4%). All coagulase+ve Staph. isolates were resistant to sulphonamide and methicillin and all sensitive to vancomycin.     

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.     

Analysis of antibiotic susceptibilities of skin wound flora in hospitalized dermatology patients. The crisis of antibiotic resistance has come to the surface

BACKGROUND: Results of an ongoing surveillance of antibiotic resistance in hospitalized dermatology patients are presented. Bacterial isolates cultured from patients with skin wounds admitted to a tertiary care dermatology inpatient unit from May 1995 through May 1996 were evaluated for resistance to commonly used antibiotics. Comparison was made with a previous survey of the same inpatient service from 1992. Our results show an alarming trend toward antibiotic resistance. OBSERVATION: In superficial skin wounds, Staphylococcus aureus constituted 77% of isolates. In leg ulcers, the frequencies of S aureus and Pseudomonas aeruginosa were approximately equal, constituting 43% and 42% of cultures, respectively. Fifty percent of S aureus isolates from leg ulcers were resistant to oxacillin, with 36% of pseudomonad isolates resistant to ciprofloxacin. In superficial wounds, oxacillin resistance in S aureus approached 25%. A comparison of antibiotic resistance profiles using data collected in 1992 for patients admitted to the same inpatient service revealed a marked increase in oxacillin and ciprofloxacin resistance in S aureus and P aeruginosa in leg ulcers, respectively (from 24% to 50% oxacillin resistance in S aureus and from 9% to 24% ciprofloxacin resistance in P aeruginosa), and superficial wounds (24% to 36% ciprofloxacin resistance in P aeruginosa). CONCLUSION: This study demonstrates the rapid emergence of antibiotic-resistant bacteria as a problem of growing significance in hospital dermatology and highlights the importance of local surveillance programs to aid in selecting antibiotic treatments.     

Pediatrics: cervical adenopathy in children

Cervical adenopathies are common in children. The four categories, based on clinical findings are acute unilateral adenitis, acute bilateral adenitis, subacute (chronic) adenitis, and cervical node cancers. Most cases of acute pyogenic adenitis-both unilateral and bilateral-respond well to early antibiotic treatment. Penicillin is the drug of choice unless Staphylococcus aureus is thought to be the infecting organism. S aureus is trated with dicloxacillin or erythromycin. Subacute adenitis due to cat scratch fever usually resolves spontaneously. Nodes due to infection with atypical mycobacteria require excision. Because cervical node cancer is usually asymptomatic, excision and pathologic study should be done for any cervical node persistently enlarged without apparent reason.     

Efficacy and tolerance of coamoxiclav in community-acquired lower respiratory tract infections in children

Amoxyclav (amoxycillin/potassium clavulanate, A/PC) was used in the treatment of 55 children with acute bronchitis and pneumonia. The drug was administered in a dose of 20-40 mg/kg body weight a day in 3 portions. The treatment course was 4 to 10 days. The treatment was performed under careful clinicoroent-genologic control. The clinical picture of the disease in the children was characterized by a moderate process which made it possible to treat the children as outpatients. The clinical efficacy amounted to 90.5 per cent. The isolates of Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Haemophilus influenzae proved to be susceptible to A/PC. It may be used as the 1st class agent in the treatment of children with lower respiratory tract infection.     

Molecular organization of the alcohol dehydrogenase loci of Drosophila grimshawi and Drosophila hawaiiensis

A total of 71 Staphylococcus aureus strains isolated from bovine mammary glands were identified and subtyped. The methods used to differentiate between the S. aureus isolates were the DNA polymorphism pattern after amplification with a Polymerase Chain Reaction using several primer combinations and phage typing. The DNA fingerprinting technique using RAPD, ERIC1R and ERIC primers proved to be useful in differentiating isolates of S. aureus. Differentiation of isolates using phage typing gave no additional information compared to the DNA technique. The outbreak of S. aureus in the herd studied was mainly caused by one S. aureus strain. Other strains were only found on three occasions, twice in subclinical infections and once from a case of clinical mastitis. In the latter case the dominant strain was isolated from a different quarter of the same cow. Four of the ten cows studied suffered from clinical mastitis. From those four cows, three remained infected with the same S. aureus strain despite antibiotic treatment.     

Expression of two different antiphagocytic M proteins by Streptococcus pyogenes of the OF+ lineage

All clinical isolates of Streptococcus pyogenes (group A streptococcus) share the ability to resist phagocytosis and grow in human blood. In many strains, this property is due to the expression of a single antiphagocytic M protein, while other strains express more than one M-like molecule, of which the role in phagocytosis resistance is unclear. In particular, all S. pyogenes strains of the OF+ lineage, representing approximately half of all isolates, express two M-like proteins, Mrp and Emm, which are immunologically unrelated. These two proteins bind different ligands that have been implicated in phagocytosis resistance: Mrp binds fibrinogen and Emm binds the complement inhibitor C4BP. Using a clinical isolate of the common serotype 22, we created mutants affected in the mrp and emm genes and characterized them in phagocytosis experiments and by electron microscopy. A double mutant mrp-emm- showed strongly decreased resistance to phagocytosis, while mrp- and emm- single mutants grew well in blood. However, optimal growth required the expression of both Mrp and Emm. Experiments in which coagulation was inhibited using the specific thrombin inhibitor, hirudin, rather than heparin, indicated that Emm is more important than Mrp for resistance to phagocytosis. Tuftlike surface structures typical for S. pyogenes were still present in the mrp-emm- double mutant, but not in a mutant affected in the regulatory gene mga, indicating that the presence of these surface structures is not directly correlated to phagocytosis resistance. Our data imply that OF+ strains of S. pyogenes express two antiphagocytic M proteins with different ligand-binding properties.     

Reactive airways dysfunction syndrome: two case reports

The antimicrobial susceptibilities of 1058 Staphylococcus aureus and 2,163 coagulase-negative staphylococci (CNS) isolates obtained from clinical specimen between 1988 and 1995, were determined against 13 anti-staphylococcal antibiotics. During the study period the resistance of Staphylococcus aureus to ciprofloxacin, ceftazidime, and norfloxacin increased significantly by 7%, 4%, and 6%, respectively (p < or = 0.001). By comparison, the antibiotic resistance of CNS to ceftazidime, oxacillin, norfloxacin, ciprofloxacin, fusidic acid, and cefoxitin increased by 20%, 17%, 15%, 14%, 12% and 10%, respectively (p < or = 0.001). Invasive and noninvasive S. aureus had similar antibiotic resistance, whereas CNS invasive isolates were more resistant than noninvasive isolates to every antibiotics, except vancomycin and fusidic acid. These differences were significant (p < 0.001) for oxacillin, cefoxitin, and clindamycin. Our observations confirm that staphylococci and particularly CNS isolates show an important rate of increased resistance to the standard antimicrobials used for therapy, and that the rate of emergence of resistance differ considerably between coagulase-positive and coagulase-negative staphylococci.     

Branched-DNA assay for detection of the mecA gene in oxacillin-resistant and oxacillin-sensitive staphylococci

The identification of methicillin-resistant staphylococcus isolates in the clinical laboratory has typically been performed by using methods that detect phenotypic expression of resistance determinants. However, these methods may be difficult to interpret and some isolates do not express resistance until selective pressure is administered. Assays that detect genetic determinants are not subject to these limitations and have been effective in distinguishing isolates that are capable of expressing the resistance phenotype. In this study, a novel branched-DNA (bDNA) hybridization assay was used to test for the mecA gene in 416 clinical staphylococcal isolates. The results were compared with those obtained by a PCR-based assay and oxacillin disk diffusion. For 155 Staphylococcus aureus and 261 coagulase-negative Staphylococcus isolates, the bDNA assay and PCR results were 100% concordant. Among the S. aureus isolates, 20 were MecA+ and 135 were MecA-. For the coagulase-negative staphylococci, 150 were MecA+ and 111 were MecA-. The results from the genotypic detection methods were compared with those obtained by oxacillin disk diffusion. No discrepancies were detected among the S. aureus isolates; however, 10 coagulase-negative isolates were MecA+ but oxacillin sensitive and 1 isolate was MecA- but oxacillin resistant. Oxacillin resistance was induced in 6 of the 10 MecA+ isolates previously classified as oxacillin sensitive. These results suggest that the bDNA method described here is a sensitive and efficient method for detection of methicillin resistance in staphylococci and that genetic detection methods may be useful for detection of potential methicillin resistance in the clinical laboratory.