An assessment of physical properties and the viability of osteoblast-like cells of cefazolin-impregnated calcium sulfate bone-void filler.

Calcium sulfate, an injectable and biodegradable bone-void filler, is widely used in orthopedic surgery. Based on clinical experience, bone-defect substitutes can also serve as vehicles for the delivery of drugs, for example, antibiotics, to prevent or to treat infections such as osteomyelitis. However, antibiotic additions change the characteristics of calcium sulfate cement. Moreover, high-dose antibiotics may also be toxic to bony tissues. Accordingly, cefazolin at varying weight ratios was added to calcium sulfate samples and characterized in vitro. The results revealed that cefazolin changed the hydration reaction and prolonged the initial setting times of calcium sulfate bone cement. For the crystalline structure identification, X-ray diffractometer revealed that cefazolin additive resulted in the decrease of peak intensity corresponding to calcium sulfate dihydrate which implying incomplete phase conversion of calcium sulfate hemihydrate. In addition, scanning electron microscope inspection exhibited cefazolin changed the morphology and size of the crystals greatly. A relatively higher amount of cefazolin additive caused a faster degradation and a lower compressive strength of calcium sulfate compared with those of uploaded samples. Furthermore, the extract of cefazolin-impregnated calcium sulfate impaired cell viability, and caused the death of osteoblast-like cells. The results of this study revealed that the cefazolin additives prolonged setting time, impaired mechanical strength, accelerated degradation, and caused cytotoxicity of the calcium sulfate bone-void filler. The aforementioned concerns should be considered during intra-operative applications.

The potential impact of discrepancies between automated susceptibility platforms and other testing metho`dologies for cefazolin in the treatment of Enterobacterales bloodstream infections.

Revised breakpoints for cefazolin (CFZ) against Enterobacterales may be difficult to implement with current automated susceptibility testing platforms and could falsely report organisms as susceptible, leading to inappropriate treatment for bloodstream infections (BSI). This was a retrospective cohort of adult patients with Enterobacterales BSI reported CFZ susceptible per Vitek®2. The primary outcome was the percentage susceptible by minimum inhibitory concentration (MIC) Gradient Test Strips and disk diffusion. Secondary outcomes included clinical outcomes between CFZ and non-CFZ-treated patients. Among 195 isolates reported CFZ-susceptible per Vitek®2, 84 (43.1%) were CFZ susceptible by MIC Gradient Test Strips vs 119 (61%) by disk diffusion. No difference was noted in 30-day all-cause mortality, secondary complications, or 30-day readmissions. Treatment failure was less likely to occur with source control (adjusted OR 0.06) and infectious disease consult (adjusted OR 0.37). There was a large degree of discrepancy between automated testing and manual methods; the clinical impact of this discrepancy warrants further investigation.

Reanalysis of cefazolin surrogate susceptibility breakpoints utilized as guidances for oral cephalosporin treatments of uncomplicated urinary tract infections: caution concerning application to cefadroxil.

Based on antimicrobial susceptibility test interpretive breakpoint criteria from Clinical and Laboratory Standards Institute and United States Committee on Antimicrobial Susceptibility Testing, cefazolin uncomplicated urinary tract infection (uUTI) surrogate breakpoints do not accurately predict cefadroxil or cephradine susceptibility when testing indicated Enterobacteriaceae species isolates. Hence, these two orally-administered cephalosporins (OC) are not equivalent spectrum substitutes for cephalexin or six other related OC agents for contemporary uUTI therapy.

Boesenbergia rotunda (L.) Mansf. extract potentiates the antibacterial activity of some ß-lactams against ß-lactam-resistant staphylococci.

OBJECTIVES: The purpose of this study was to investigate the effect of Boesenbergia rotunda (L.) Mansf. extract (BRE) and peptidoglycan inhibitor antibiotics, alone and in combination, against ß-lactam-resistant staphylococci. METHODS: Antibacterial and synergistic activities of BRE alone and in combination with ampicillin (AMP), cloxacillin (CLX), cefazolin (CZO) or vancomycin (VAN) were evaluated against two ß-lactam-resistant Staphylococcus aureus (BRSA) isolates and one ß-lactam-resistant Staphylococcus epidermidis (BRSE) isolate. The activities were confirmed by killing curve assays. The preliminary antimicrobial action was elucidated by transmission electron microscopy (TEM) and cytoplasmic membrane (CM) permeability assay. RESULTS: All tested staphylococci were inhibited by BRE at a minimum inhibitory concentration (MIC) of 16µg/mL. Two BRSA strains showed high resistance to CLX, AMP and CZO, whilst BRSE was resistant to CLX and AMP. All tested isolates remained susceptible to VAN. Chequerboard assay demonstrated a fractional inhibitory concentration index (FICI) of 0.50 for the BRE+CLX combination against the BRSA strains. Killing curve determinations confirmed the antibacterial and synergistic activities. TEM revealed collapse of the CM in BRE-treated cells and damage both of the CM and peptidoglycan (PG) in BRE+CLX-treated cells. The CM permeability assay showed that either BRE or nisin alone as well as BRE+CLX significantly induced leakage of OD260nm-absorbing materials. CONCLUSIONS: BRE potentiated the activity of ß-lactams, particularly CLX, against ß-lactam-resistant staphylococci by damaging the CM and PG layer, leading to leakage of intracellular material. Combination of BRE and ß-lactams provides a potential way forward in developing novel antistaphylococcal agents.

Changes in Bacterial Resistance Patterns of Pediatric Urinary Tract Infections and Rationale for Empirical Antibiotic Therapy.

BACKGROUND: The causative agent spectrum and resistance patterns of urinary tract infections in children are affected by many factors. AIMS: To demonstrate antibiotic resistance in urinary tract infections and changing ratio in antibiotic resistance by years. STUDY DESIGN: Retrospective cross-sectional study. METHODS: We analysed antibiotic resistance patterns of isolated Gram (-) bacteria during the years 2011-2014 (study period 2) in children with urinary tract infections. We compared these findings with data collected in the same centre in 2001-2003 (study period 1). RESULTS: Four hundred and sixty-five uncomplicated community-acquired Gram (-) urinary tract infections were analysed from 2001-2003 and 400 from 2011-2014. Sixty-one percent of patients were female (1.5 girls : 1 boy). The mean age of children included in the study was 3 years and 9 months. Escherichia coli was the predominant bacteria isolated during both periods of the study (60% in study period 1 and 73% in study period 2). Bacteria other than E. coli demonstrated a higher level of resistance to all of the antimicrobials except trimethoprim-sulfamethoxazole than E. coli bacteria during the years 2011-2014. In our study, we found increasing resistance trends of urinary pathogens for cefixime (from 1% to 15%, p<0.05), amikacin (from 0% to 4%, p<0.05) and ciprofloxacin (from 0% to 3%, p<0.05) between the two periods. Urinary pathogens showed a decreasing trend for nitrofurantoin (from 17% to 7%, p=0.0001). No significant trends were detected for ampicillin (from 69% to 71%), amoxicillin-clavulanate (from 44% to 43%), cefazolin (from 39% to 32%), trimethoprim-sulfamethoxazole (from 32% to 31%), cefuroxime (from 21% to 18%) and ceftriaxone (from 10% to 14%) between the two periods (p>0.05). CONCLUSION: In childhood urinary tract infections, antibiotic resistance should be evaluated periodically and empiric antimicrobial therapy should be decided according to antibiotic sensitivity results.

[Effect of the Combination of Xiyanping and Cefazolin on the Function of Neutrophils in Mice].

Xiyanping is used to treat infectious diseases with antibiotics in clinic. The aim of this study is to investigate the mechanism of Xiyanping through studying the effect of the combination of Xiyanping with Cefazolin on the chemotaxis and phagocytic function of peripheral blood neutrophils in mice. Ten healthy mice were in control group. Forty healthy mice in experimental group were infected with staphylococcus aureus, and were randomly divided further into four groups, i. e. model group, Xiyanping group, Cefazolin group and combination group (Xiyanping with Cefazolin). Mice in the control group and model group were given normal saline (NS) through abdomen while those in other groups were given Xiyanping, Cefazolin, and Xiyanping with Cefazolin, respectively. The chemotaxis of peripheral blood neutrophils was detected with the transwell method, and the phagocytic function of peripheral blood neutrophils was analyzed with flow cytometry (FCM). In the present study, there was no significance on the chemotactic index of peripheral blood neutrophils in all the groups (P > 0.05). The actual phagocytotic rate and index of peripheral blood neutrophils in the blank group, Xiyanping group, and the combination group were significantly higher than those of the model group and Cefazolin group (P < 0.05). However, those were not significant in the blank group, Xiyanping group, and the combination group (P > 0.05) or between the model group and Cefazolin group (P> 0.05). Our results suggested the combination of Xiyanping and Cefazolin could enhance the therapeutic effect by improving the phagocytic function of peripheral blood neutrophils.

Synthesis, characterization, and antimicrobial activity of poly(acrylonitrile-co-methyl methacrylate) with silver nanoparticles.

Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field.

Cefazolin-sodium has no adverse effect on fracture healing in an experimental rabbit model.

OBJECTIVES: This study aims to investigate whether cefazolin-sodium has any adverse effect on fracture healing in an experimental rabbit model. MATERIALS AND METHODS: The study was performed on 50 male New-Zealand white rabbits. Under general anesthesia, closed double fracture of middle one-third of the tibia-fibula of the left lower extremity of the subjects was produced by manual compression followed by closed reduction of fracture and long leg circular cast was applied. Subjects were divided randomly into five groups including 10 rabbits in each group. The first and second group were administered ciprofloxacin 50 mg/kg SC bid and cefazolin-sodium 50 mg/kg IM on the seventh day of fracture. The third group was applied a single high-dose of vitamin D (50.000 IU/kg) IM following fracture. The fourth group was applied daily vitamin E (alpha tocopherol) 20 mg/kg IM for five days from one hour before the production of fracture. Control group did not receive any treatment before and after fracture. Initial and control X-ray examinations were performed immediately and four weeks after production of fracture, respectively. At the end of the fourth week, animals were sacrificed and a histological examination of the fracture site was performed. RESULTS: Histological evaluation showed that the histological grade of the fracture healing was significantly lower in the ciprofloxacin group, while it was significantly higher in the cefazolin-sodium, vitamin D and vitamin E groups, compared to control group (p<0.005). CONCLUSION: Significantly improved histological grade of the fracture healing in subjects treated with cefazolin-sodium than controls suggest that it may be reasonable to choose cefazolin-sodium as an antibiotic therapy for the treatment of infection in patients with bone fractures.

In vitro compatibility study of cephalosporin with intraocular irrigating solutions and intracameral medications.

BACKGROUND: To study the compatibility of cephalosporins with intraocular irrigating solutions and intracameral medications commonly used in cataract surgery. DESIGN: The was an in vitro experiment conducted in the Research Laboratory of the Department of Microbiology, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. SAMPLES: Three cephalosporins--cefazolin, cefuroxime and ceftazidime--were separately diluted and mixed with irrigating solutions and intracameral medications to form 192 samples and 12 control solutions. METHODS: The cephalosporins were dissolved in normal saline and further diluted to the concentration of 1 mg in 0.1 mL with normal saline, Ringer's solution, balanced salt solution and fortified balanced salt solutions. These were mixed with balanced salt solutions or fortified balanced salt solutions, with adrenaline, acetylcholine or carbachol and kept at 37°C for 2 h. The concentrations of free cephalosporins were measured with rapid high-performance liquid chromatography at baseline (0 h) and at 2 h. MAIN OUTCOME MEASURES: Free concentrations of cephalosporins at 2 h were compared with mean baseline (0 h) value. A difference of 3 standard deviations or more was considered statistically significant. RESULTS: At 2 h there was a significant drop in the cefuroxime concentration in preparations in which cefuroxime was diluted with normal saline (P < 0.01). In all preparations, the final concentrations of cephalosporins were higher than the minimal inhibitory concentrations (MIC(90)) for microbials commonly isolated from the external eye. CONCLUSION: Cefazolin, cefuroxime and ceftazidime were compatible with irrigating solutions and intracameral medications commonly used in cataract surgery.

[Cefazolin efficacy and antibiotic sensitivity against pathogenic bacteria in pediatric with acute upper urinary tract infection].

Acute upper urinary tract infection may cause sepsis, especially in neonates and infants, mandating the choice of appropriate, effective antibacterials minimizing increasing bacterial resistance. Frequently prescribing broad-spectrum cephalosporinin is one such example. Different antibacterial therapies are initiated clinically due to treatment protocol differences among institutions, disease severity, etc. We studied the efficacy of cefazolin (CEZ), a first-generation cephalosporin, as first-line parenteral treatment in acute upper urinary tract infection. We found that 88.9% of microbial infections have indications for CEZ. CEZ efficacy is 91.3%, and 97.2% of urine cultures show negative results. Escherichia coli sensitivity to antibacterial agents is 90.9% of the minimal inhibitory concentration (MIC) < 4 for CEZ, 93.9% of MIC < 1 for ceftazidime (CAZ), 63.6% of MIC < 4 for ampicillin, and 81.8% of MIC < 2 for gentamicin. CEZ thus has the same efficacy as CAZ and is more effective than other antibacterial agents against E. coli. We concluded that CEZ is an effective antibacterial in initial antibacterial pediatric therapy in acute upper urinary tract infection.

Cefazolin plus minocycline against a clinical isolate of Vibrio vulnificus: in vitro and animal studies.

Cefotaxime plus minocycline has been shown to have synergistic activity against Vibrio vulnificus; however, the clinical role of cefazolin in combination with minocycline in immunocompromised hosts has not been established. Therefore, antimicrobial susceptibility of the V. vulnificus clinical isolate Vv05191 was studied by the agar dilution method. Antibacterial activity of cefazolin, minocycline, and a combination of the two drugs was investigated by time-kill studies in vitro and further examined for therapeutic efficacy in a murine model. When cefazolin at a combination of 4 mg/L (1/2 x MIC) was combined with minocycline at a concentration of 0.03 mg/L (1/2 x MIC), sustained inhibitory activity was noted until 24 h. In BALB/cByJ mice with cyclophosphamide-induced neutropenia, an inoculum of 1.5 x 10(8) CFU caused death within 96 h when the infected mice were treated by cefazolin (400 mg/kg every 3 h), while 6.3% of mice survived when treated by minocycline (4 mg/kg stat, then 2 mg/kg every 12 h). However, 62.5% of mice survived for 96 h when mice were treated by cefazolin (400 mg/kg every 3 h) plus minocycline (4 mg/kg stat, then 2 mg/kg every 12 h) (P = 0.002, log rank test). In conclusion, cefazolin in combination with minocycline exhibits in vitro synergistic antibacterial activity against V. vulnificus and provides a therapeutic advantage in neutropenic mice with V. vulnificus infection.

Inoculum effect with cefazolin among clinical isolates of methicillin-susceptible Staphylococcus aureus: frequency and possible cause of cefazolin treatment failure.

Methicillin (meticillin)-susceptible Staphylococcus aureus (MSSA) strains producing large amounts of type A beta-lactamase (Bla) have been associated with cefazolin failures, but the frequency and impact of these strains have not been well studied. Here we examined 98 MSSA clinical isolates and found that 26% produced type A Bla, 15% type B, 46% type C, and none type D and that 13% lacked blaZ. The cefazolin MIC(90) was 2 microg/ml for a standard inoculum and 32 microg/ml for a high inoculum, with 19% of isolates displaying a pronounced inoculum effect (MICs of >or=16 microg/ml with 10(7) CFU/ml) (9 type A and 10 type C Bla producers). At the high inoculum, type A producers displayed higher cefazolin MICs than type B or C producers, while type B and C producers displayed higher cefamandole MICs. Among isolates from hemodialysis patients with MSSA bacteremia, three from the six patients who experienced cefazolin failure showed a cefazolin inoculum effect, while none from the six patients successfully treated with cefazolin showed an inoculum effect, suggesting an association between these strains and cefazolin failure (P = 0.09 by Fisher's exact test). In summary, 19% of MSSA clinical isolates showed a pronounced inoculum effect with cefazolin, a phenomenon that could explain the cases of cefazolin failure previously reported for hemodialysis patients with MSSA bacteremia. These results suggest that for serious MSSA infections, the presence of a significant inoculum effect with cefazolin could be associated with clinical failure in patients treated with this cephalosporin, particularly when it is used at low doses.

[Antibiotic resistance of Escherichia coli from community-acquired urinary tract infections. What antimicrobial to use?]. / Resistencia antimicrobiana en la infección urinaria por Escherichia coli adquirida en la comunidad. Cuál antibiótico voy a usar?

OBJECTIVE: Determine antibiotic resistance of community-acquired uropathogen Escherichia coli and infer therapeutic options. MATERIAL AND METHODS: E. coli strains isolated from urine during a one-year period were studied. Identification and susceptibility tests were performed. RESULTS: A total of 652 isolates were included from patients in two institutions, a healthcare clinic 303 (46.5%) and a hospital 349 ( 53.5%). The antimicrobials with higher resistance rates were ampicillin 67.2%, trimethoprim-sulfametoxazole 59.2%, cefazolin 35.6% and ciprofloxacin 24.7%. CONCLUSIONS: Resistance to trimethoprim-sulfamethoxazole and ciprofloxacin used for empiric treatment in community urinary infections is high, and there are few available treatment options.

Resistencia antimicrobiana en la infección urinaria por Escherichia coli adquirida en la comunidad: ¿cuál antibiótico voy a usar? / Antibiotic resistance of Escherichia coli from community-acquired urinary tract infections: what antimicrobial to use?

OBJETIVO: Determinar la resistencia del uropatógeno comunitario más frecuente, Escherichia coli, a diversos antimicrobianos y deducir opciones de manejo empírico. MATERIAL Y MÉTODOS: Del 14 de julio de 2005 al 13 julio de 2006 se estudiaron cepas de Escherichia coli aisladas de urocultivos de pacientes que asistieron a la consulta externa de la Clínica Nova y del Hospital San José, en Monterrey, Nuevo León, México. Se identificó la bacteria y se determinó susceptibilidad a antibióticos mediante método automatizado. Se compararon los resultados entre las dos instituciones y la frecuencia de resistencia a antimicrobianos entre mujeres de entre 15 a 50 años de edad y > 50. RESULTADOS: Se analizaron 652 urocultivos: 303 (46.5 por ciento) de Clínica Nova y 349 (53.5 por ciento) del Hospital San José. Las cepas aisladas fueron resistentes a ampicilina, en 67.2 por ciento; a trimetoprim-sulfametoxazol, en 59.2 por ciento; a cefazolina, en 35.6 por ciento, y a ciprofloxacino, en 24.7 por ciento. CONCLUSIONES: La resistencia a trimetoprim-sulfametoxazol y ciprofloxacino, considerados de elección en el manejo empírico de las infecciones de vías urinarias adquiridas en la comunidad, es alta. Las opciones de manejo son pocas.

OBJECTIVE: Determine antibiotic resistance of community-acquired uropathogen Escherichia coli and infer therapeutic options. MATERIAL AND METHODS: E. coli strains isolated from urine during a one-year period were studied. Identification and susceptibility tests were performed. RESULTS: A total of 652 isolates were included from patients in two institutions, a healthcare clinic 303 (46.5 percent) and a hospital 349 ( 53.5 percent). The antimicrobials with higher resistance rates were ampicillin 67.2 percent, trimethoprim-sulfametoxazole 59.2 percent, cefazolin 35.6 percent and ciprofloxacin 24.7 percent. CONCLUSIONS: Resistance to trimethoprim-sulfamethoxazole and ciprofloxacin used for empiric treatment in community urinary infections is high, and there are few available treatment options.

Trends in resistance to ciprofloxacin, cefazolin, and gentamicin in the treatment of bacterial keratitis.

PURPOSE: The aim of this study was to evaluate the microbial profile, resistance patterns, and antibiotic sensitivity of bacterial keratitis to three commonly used ocular antibiotics. METHODS: All cases of bacterial keratitis referred to the Massachusetts Eye and Ear Infirmary Microbiology Laboratory from two consecutive annual 10-month periods were reviewed. The bacterial profile and resistance to ciprofloxacin, cefazolin, and gentamicin was evaluated within the two intervals. RESULTS: Of the 485 cultures analyzed, 66.4% (322) were positive for bacterial isolates. Of these, 19.2% were polymicrobial, 87.5% were gram-positive, and 12.5% were gram-negative. The most prevalent isolate was coagulase-negative Staphylococcus (45.5%), followed by S. aureus (15.2%). The resistance patterns for gram-positive bacteria for ciprofloxacin for the first versus second time interval were 12% and 22% (P = 0.04) respectively, for cefazolin 13% and 23% (P = 0.04), and for gentamicin 4% and 7% (P = 0.36). The resistance patterns for gram-negative bacteria for ciprofloxacin, cefazolin, and gentamicin were not significantly different in the two tested time periods (all P > 0.05). CONCLUSIONS: There was increased resistance of gram-positive organisms to ciprofloxacin and cefazolin, but not gentamicin, in the two examined time periods. Increased resistance to these commonly used antibiotics emphasizes the need for close follow-up after initial empiric treatment, and maintaining a low threshold for selecting alternative therapy.

An analysis of a community-acquired pathogen in a Kentucky community: methicillin-resistant Staphylococcus aureus.

CONTEXT: Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have been reported in patients with recognized predisposing risk factors in several cities in the United States and across the world. Reviewing risk factors in adult patients with CA-MRSA in Kentucky has not been reported. OBJECTIVE: To determine the risk factors of 15 patients with CA-MRSA in Louisville KY, to compare the sensitivities of each pathogen and to recommend management. SETTING: An infectious diseases private practice in Louisville, KY. MATERIALS AND METHODS: This is a case series of patients with CA-MRSA. The disease course for each patient was reviewed for risk factors, such as participation in physical contact sports and prison exposure. The antimicrobial sensitivities of each pathogen were also reviewed. Recommendations were produced from the information obtained. RESULTS: A total of 15 patients were reviewed. Five patients had a family member or significant-other with a current CA-MRSA infection. Three had traditional risk factors (healthcare workers). All of the isolates were susceptible to vancomycin and resistant to oxacillin. All of the isolates tested for trimethoprim/sulfamethoxazole (TMP/SMX), tetracycline, and rifampin were sensitive. A majority (83%) of those tested for clindamycin and only 50% of those tested for levofloxacin were sensitive. All isolates tested for cefazolin were resistant. CONCLUSIONS: An emerging risk factor for acquiring an MRSA skin and soft tissue infection is having a significant-other with a current diagnosis of CA-MRSA. After incision and drainage, a review of the antimicrobial sensitivities indicates that oral treatment may be adequate for a selection of cases.

Prevention of infection with tobramycin-containing bone cement or systemic cefazolin in an animal model.

We investigated in an animal model the efficacy of tobramycin-containing bone cement and systemic cefazolin for infection prophylaxis. In 18 female rabbits, the femoral cavity was inoculated with Staphylococcus aureus before injection of bone cement. The first group of six rabbits received tobramycin-containing Simplex-P bone cement. Two other groups of six rabbits received plain Simplex-P bone cement. Preoperatively, in one of the two latter groups cefazolin was administered intravenously. The other group served as untreated controls. The rabbits were monitored for clinical signs of infection. At 7 days' follow-up, the femora were harvested and cultures from the bone adjacent to the cement plug were quantified. Cultures from the rabbits which received antibiotic prophylaxis (either cefazolin systemically or tobramycin-containing bone cement) were all negative. In contrast, all rabbits in the untreated control group had positive cultures. These rabbits also had other signs of infection such as an elevated erythrocyte sedimentation rate and loss of body weight. Culture results were confirmed by the absence of bacterial DNA in the polymerase chain reaction hybridization assay. In conclusion, we found that both tobramycin-containing bone cement and systemic cefazolin are effective in preventing implant bed infection in rabbits up to 7 days after contamination with S. aureus.

Antibiotic resistance patterns of group B streptococcus in antenatal genital cultures.

OBJECTIVE: To identify the antibiotic susceptibility patterns of group B streptococcus (GBS) isolated from antenatal genital screening cultures. STUDY DESIGN: One hundred thirty-five sequential GBS isolates underwent susceptibility testing by Kirby-Bauer disk diffusion to a variety of commonly used antibiotics. RESULTS: All isolates were susceptible to cefazolin, chloramphenicol and vancomycin. Resistance to clindamycin and erythromycin, the currently recommended alternative antibiotics for intrapartum GBS prophylaxis in penicillin-allergic women, was found in 8.2% and 9.6% of GBS isolates tested, respectively. CONCLUSION: These findings raise concerns regarding the need for both confirmation of a history of penicillin allergy in pregnant women and performance of antibiotic susceptibility testing on GBS isolated in genital screening cultures from penicillin-allergic patients.

Fluoroquinolones in the treatment of bacterial keratitis.

PURPOSE: We evaluated the potential role of three topical fluoroquinolones in the treatment of bacterial keratitis by means of a laboratory database. METHODS: Antibiotic susceptibilities were determined for 153 isolates from patients with bacterial keratitis. Results were analyzed for each fluoroquinolone individually and in combination with cefazolin. RESULTS: Predicted susceptibility to each cefazolin-fluoroquinolone combination (98.7%) was superior to that for single-agent therapy with ofloxacin (88.2%), ciprofloxacin (82.3%), or norfloxacin (80.4%) (P = .0002). A cefazolin-fluoroquinolone combination (98.7%) was comparable to a cefazolin-gentamicin combination (97.4%). CONCLUSIONS: Combination therapy with cefazolin and a fluoroquinolone offers a reasonable alternative for the treatment of bacterial keratitis. Single-agent therapy with fluoroquinolones for vision-threatening bacterial keratitis is not advised.

Antibacterial activity of alimentary plants against Staphylococcus aureus growth.

Alimentary plants were screened for antibacterial activity against a penicillin G resistant strain of Staphylococcus aureus. Twenty-five samples of plant material corresponding to 21 species from 13 families were used. Both aqueous and ethanol extracts were obtained from them. Antibacterial activity was determined by the agar-well diffusion method, using cephazolin as a standard antibiotic. Seventeen ethanol extracts were found active. Eugenia caryophyllata (clavo de olor*) flowers, Myristica fragans (nuez moscada*) seeds, Theobroma cacao (cacao*) seed bark, Triticum sp (trigo*) fruit, Zea mays (maíz*) fruit and Piper nigrum (pimienta*) ripe fruit produced some of the more active extracts (* = Argentine vulgar names).