Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Enterococcus spp.”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1998

Studying the effect of temperature on microbial growth using multiplicative model.

The specific growth rates of Brochothrix thermosphacta, Listeria monocytogenes, Yersinia enterocolitica, Bacillus cereus, Escherichia coli O157:H7, Salmonella spp., Staphylococcus aureus and Clostridium perfringens at various temperatures were taken from the Food MicroModel database, and the data sets of specific growth rate versus temperature were fitted using the multiplicative model (r = a Td, r = specific growth rate; T = temperature; a, d = regression parameters). The exponential d-value derived from microbial growth at suboptimum temperatures reflected the effectiveness of temperature in enhancing growth. A microorganism with a large d-value exhibited a large increment of growth rate as temperature increased. The d-value of a microorganism was related to the temperature range for growth. The temperature range for the growth of psychrotrophs was usually narrow for B. thermosphacta and Y. enterocolitica; hence the d-values of these two psychrotrophs were close to 1 whereas d-values of mesophiles, such as B. cereus, E. coli O157:H7, Salmonella spp., and S. aureus, were 2.31-2.90, and the d-value of C. perfringens, a thermophile, was 3.29. The values of parameter a of the model were affected by extra salt added into cultures. For all the strains mentioned above, the a-values decreased when the cultures contained higher levels of salt. The lowering of the a-value implied that the influence of temperature on the growth rate in the model was reduced. The change of the d-value was dependent on the capability of the microorganism to overcome the obstacle to growth and was affected by the composition of the nutrients and by inhibitory factors in the culture. The influence of environmental factors on the d-value was also found in Chinese sausages. The d-value of a dominant spoilage strain of Enterococcus sp. derived from sausages was 0.833 whereas the d-value derived from MRS cultures was 2.36. In refrigerated foods which usually contained some preservatives and were stored at low temperature, the d-value of psychrotrophic spoilage bacteria was around 1. In this case, the linear model could be a reasonable choice for predicting the proliferation of spoilage bacteria.

Culture Media↗
PubMed2006

Faecal coliform bacteria in Febros river (northwest Portugal): temporal variation, correlation with water parameters, and species identification.

Febros river water was sampled weekly, during 35 successive weeks, and analyzed for microbiological (total coliforms, faecal coliforms, faecal streptococci and enterococci) and chemical-physical (ammonia and temperature) parameters. All microbiological parameters were highly correlated with each other and with ammonia, suggesting that the simultaneous determination of all variables currently in use in the evaluation of the microbiological quality of waters is probably redundant, and could be simplified, and that ammonia should be tested as a sentinel parameter of the microbiological pollution load of Febros river. From the strains isolated from positive tubes of the faecal coliforms test (multiple tube fermentation technique) and retested in this assay, Escherichia coli, Klebsiella oxytoca and Klebsiella pneumoniae subsp. pneumoniae strains were positive, indicating that the faecal coliforms test is not totally specific for Escherichia coli, and can detect other bacteria. Considering that these Klebsiella spp. are not necessarily of faecal origin, it was concluded that the faecal coliforms test can overestimate true faecal pollution. From the strains isolated from positive tubes of the faecal coliforms procedure, only Escherichia coli strains were clearly positive in the beta-D-glucuronidase test. All other species were negative or very weakly positive, suggesting that the assay of the beta-D-glucuronidase activity is less prone to false positives than the faecal coliforms test in the quantification of Escherichia coli in environmental waters.

Ammonia↗
PubMed1980

Evidence of thermonuclease production by Bacillus spp. and enterococci in naturally contaminated cheese.

Of 105 thermonuclease-positive (TNase-positive) cheese samples comprising 13 types, 92 (87.6%) contained coagulase-positive staphylococci, whereas 9 (8.6%) contained microorganisms other than staphylococci as the major contaminants. Of the latter group, six samples contained Bacillus spp. comprising three species (B. cereus, B. licheniformis, and B. subtilis), and three contained mainly enterococci (Streptococcus faecalis), which were proven to be TNase producers. The organisms responsible for TNase production in the other four samples (3.8%) are not known, because isolates from these samples failed to produce the enzyme. Unlike staphylococcal TNase, a greater part of nonstaphylococcal TNase remains in the cheese homogenate after extraction of the enzyme at pH 3.8 instead of pH 4.5.

Bacillus↗
PubMed2005

Critical issues in the clinical management of complicated intra-abdominal infections.

Intra-abdominal infections differ from other infections through the broad variety in causes and severity of the infection, the aetiology of which is often polymicrobial, the microbiological results that are difficult to interpret and the essential role of surgical intervention. From a clinical viewpoint, two major types of intra-abdominal infections can be distinguished: uncomplicated and complicated. In uncomplicated intra-abdominal infection, the infectious process only involves a single organ and no anatomical disruption is present. Generally, patients with such infections can be managed with surgical resection alone and no antimicrobial therapy besides perioperative prophylaxis is necessary. In complicated intra-abdominal infections, the infectious process proceeds beyond the organ that is the source of the infection, and causes either localised peritonitis, also referred to as abdominal abscess, or diffuse peritonitis, depending on the ability of the host to contain the process within a part of the abdominal cavity. In particular, complicated intra-abdominal infections are an important cause of morbidity and are more frequently associated with a poor prognosis. However, an early clinical diagnosis, followed by adequate source control to stop ongoing contamination and restore anatomical structures and physiological function, as well as prompt initiation of appropriate empirical therapy, can limit the associated mortality. The biggest challenge with complicated intra-abdominal infections is early recognition of the problem. Antimicrobial management is generally standardised and many regimens, either with monotherapy or combination therapy, have proven their efficacy. Routine coverage against enterococci is not recommended, but can be useful in particular clinical conditions such as the presence of septic shock in patients previously receiving prolonged treatment with cephalosporins, immunosuppressed patients at risk for bacteraemia, the presence of prosthetic heart valves and recurrent intra-abdominal infection accompanied by severe sepsis. In patients with prolonged hospital stay and antibacterial therapy, the likelihood of involvement of antibacterial-resistant pathogens must be taken into account. Antimicrobial coverage of Candida spp. is recommended when there is evidence of candidal involvement or in patients with specific risk factors for invasive candidiasis such as immunodeficiency and prolonged antibacterial exposure. In general, antimicrobial therapy should be continued for 5-7 days. If sepsis is still present after 1 week, a diagnostic work up should be performed, and if necessary a surgical reintervention should be considered.

Abdominal Abscess↗
PubMedDate not supplied

[The antibacterial resistance of the strains making up the components of probiotic preparations].

The spectrum of the antibiotic resistance of 21 strains of normal microflora, mainly forming constituents of widely used probiotics to 25 antibacterial preparations. Lactobacillus spp. were prevalent in the strains under test. The spectrum of the antibiotic resistance of lactobacilli varied, the gradation of resistance being more pronounced with respect to strains and not species. Both highly sensitive and highly resistant Lactobacillus strains were found: L. acidophilus (a component of biopreparation "Linex"), L. plantarum 8RA3, L. fermentum 90T4C (probiotic "Lactobacterin"), L. fermentum BL96. Bacteria used as the components of combined preparation "Linex" exhibited the highest resistance to a number of modern antibiotics. Strains of bifidobacteria were found to be highly sensitive to antibiotics.

Bifidobacterium↗
PubMed2000

Occurrence of Salmonella spp in estuarine and coastal waters of Portugal.

The presence of Salmonella and its relationship with indicator organisms of fecal pollution, such as total coliforms, fecal coliforms and fecal streptococci, was studied at two marine zones in Portugal. Seventeen different Salmonella serotypes were isolated and identified, S. virchow was the most frequently isolated (21.6%). In addition, a high percentage (35.1%) was recorded for some Salmonella serotypes of clinical significance, namely S. enteritidis, S. infantis, S. typhimurium and S. virchow. In any of the samples from the two zones Salmonella was not detected in the absence of any of the indicator organisms. However, the incidence of Salmonella as a function of indicator concentration intervals established by the EEC standards was 0, 10 and 19.3% at guide values of total coliforms, fecal coliforms and fecal streptococci, respectively in the Faro samples (south of Portugal). In contrast, Salmonella incidence rates of 37.5, 36.4 and 33.3% were recorded at the corresponding guide values the Caminha samples (north of Portugal). No significant correlations (p>0.005) were obtained between Salmonella and the indicators at the sampling stations; however, total coliforms and fecal streptococci were the indicators most closely related to Salmonella in Caminha and Faro samples, respectively. Survival experiments in Escherichia coli, Enterococcus faecalis and S. typhimurium, using diffusion chambers, were performed to verify whether the lack of correlation between indicators and Salmonella was due to different inactivation rates in seawater. The results indicate that survival percentages of the three microorganisms tested were similar after 48 h of exposure to seawater.

Bathing Beaches↗
PubMed2000

Antimicrobial activities of mefloquine and a series of related compounds.

Mefloquine was found to have bactericidal activity against methicillin- and fluoroquinolone-susceptible and -resistant strains of Staphylococcus aureus and Staphylococcus epidermidis and gentamicin- and vancomycin-resistant strains of Enterococcus faecalis and Enterococcus faecium. The MICs were 16 microg/ml, and the minimal bactericidal concentrations (MBCs) were 16 to 32 microg/ml. These concentrations cannot be achieved in serum. Mefloquine was active at a more achievable concentration against penicillin-susceptible and -resistant Streptococcus pneumoniae, with MICs of 0.2 to 1.5 microg/ml. Mefloquine was not active against gram-negative bacteria and yeasts. In an attempt to find more active derivatives, 400 mefloquine-related compounds were selected from the chemical inventory of The Walter Reed Army Institute of Research. We identified a series of compounds containing a piperidine methanol group attached to pyridine, quinoline, and benzylquinoline ring systems. These had activities similar to that of mefloquine against S. pneumoniae but were far more active against other gram-positive bacteria (MICs for staphylococci, 0.8 to 6.3 microg/ml). They had activities similar to that of amphotericin B against Candida spp. and Cryptococcus neoformans. Combinations of the compounds with gentamicin and vancomycin were additive against staphylococci and pneumococci. The MIC and MBC of gentamicin were decreased by four- to eightfold when this drug was combined with limiting dilutions of the compounds. There was no antagonism with other antimicrobial drugs. The compounds were rapidly bactericidal. They appear to act by disrupting cell membranes. Combinations of the compounds with aminoglycoside antibiotics may have potential for therapeutic use.

Anti-Bacterial Agents↗
PubMed2006

Identification of dominant bacteria in feces and colonic mucosa from healthy Spanish adults by culturing and by 16S rDNA sequence analysis.

The aim of this work was to examine by culturing the changes in the total and indicator populations of the feces of two individuals over 1 year and to identify the dominant microbial components of a single sample of feces from each donor. Populations and dominant bacteria from a sample of colonic mucosa from a further individual were also assessed. The culture results were then compared to those obtained with the same samples by 16S rDNA cloning and sequencing. High interindividual variation in representative microbial populations of the gastrointestinal tract (GIT) was revealed by both the culture and the culture-independent techniques. Species belonging to Clostridium clusters (XIVa, IV, and XVIII) predominated in both the fecal and the mucosal samples (except in the mucose cultured isolates), members of Clostridium coccoides cluster XIVa being the most numerous microorganisms. Species of gamma-proteobacteria (Escherichia coli and Shigella spp.), bifidobacteria, and actinobacteria appeared in lower numbers than those of clostridia. From the mucosal cultured sample, only facultative anaerobes and bifidobacteria were recovered, suggesting destruction of the anaerobe population during processing. In accordance with this, the microbial diversity revealed by 16S rDNA sequence analysis was greater than that revealed by culturing. Despite large interindividual differences, distinct human communities may have group-associated GIT microbiota characteristics, such as the low number of Bacteroides seen in the subjects in this study.

Adult↗
PubMed1997

[Federal investigations on the distribution and in vitro resistance of udder pathogenic bacteria in the milk of cows with subclinical mastitis].

1644 quarter milk samples of 948 dairy cows with subclinical mastitis, collected from 63 veterinary practices all over Germany origined by 262 livestocks with problems in udder health were examined semiquantitatively by "Aulendorfer Mastitistest" for cell count and additionally bacteriologically. Potentially udder pathogenic bacteria were tested for in vitro-sensitivity to penicillin G, ampicillin, oxacillin, cefacetril, tylosin, neomycin, gentamicin, polymyxin B and enrofloxacin. 24.5% of all tested milk samples were bacteriologically negative. In 35.3% of the bacteriological positive milk samples Staphylococcus (S) aureus was detected. Enterococci, Streptococcus (Sc.) uberis, Sc. dysgalactiae and Sc. agalactiae were found in 8.9%, 8.2%, 8.1% and 4.9% of all positive milk samples, respectively. G-streptococci were found only occasionally. Apathogenic bacteria like coagulase-negative staphylococci, micrococci, aerobic bacilli and coryneforms were detected in 45.0% of all positive milk samples. Enterobacteriaceae (E. coli, klebsiella spp., proteus spp. and other coliforms) were isolated in 3.3% of all cases and should be considered as insignificant for the subclinical mastitis of dairy cows in Germany. Against S. aureus cefacetril and oxacillin were mostly effective in vitro, whereas penicillin G was ineffective because 40% of these bacteria are penicillinase-positive. Streptococci and enterococci were mostly sensitive to cefacetril, oxacillin, penicillin G and ampicillin. Concerning the distribution of bacteria regional differences were recognized. Regional differences concerning in vitro-sensitivity were negligible. The results are discussed.

Animals↗
PubMed1994

Emerging trends in antimicrobial resistance in surgical infections. A review.

During the past decade there have been major changes in the susceptibility of bacteria that cause surgical infections. Resistance to common bacteria is worldwide, both in developed and developing countries. Almost all species of bacteria can develop resistance to antimicrobial agents, and resistance can readily be transferred among bacteria by transmissible elements called plasmids. One of the most important forms of resistance has been the inactivation of antibiotics, particularly penicillins and cephalosporins. The organisms involved in surgical infections include staphylococci, streptococci, enterococci, members of the Enterobacteriaceae, Pseudomonads, and anaerobes. Today virtually all Staphylococcus aureus are resistant to penicillins. Coagulase-negative staphylococci are also increasingly important causes of infection, particularly in cardiovascular surgery, where they may cause serious postoperative complications. Like S aureus, coagulase-negative staphylococci, primarily S epidermidis, also produce beta-lactamases and can be resistant to all beta-lactam antibiotics because of altered penicillin-binding proteins. New beta-lactamases, which destroy extended-spectrum beta-lactam antibiotics, have developed in Enterobacteriaceae, and all Pseudomonas spp. possess beta-lactamases. Various techniques have been used to overcome resistance, one of which is the development of beta-lactamase inhibitors. Currently there are three compounds that are effective inhibitors of many beta-lactamases: clavulanate, sulbactam, and tazobactam. The problem of resistance in surgical infections will not disappear. Increasingly complex operations will be done on more debilitated patients. The development of beta-lactamase inhibitors combined with highly active beta-lactam antibiotics has provided a way of overcoming this form of resistance.

Bacteroides↗
PubMed1979

Microbial impact of Canada geese (Branta canadensis) and whistling swans (Cygnus columbianus columbianus) on aquatic ecosystems.

Quantitative and qualitative analyses of the intestinal bacterial flora of Canada geese and whistling swans were carried out with the finding that wild birds harbor significantly more fecal coliforms than fecal streptococci. The reverse was typical of captive and fasting birds. Neither Salmonella spp. nor Shigella spp. were isolated from 44 migratory waterfowl that were wintering in the Chesapeake Bay region. Enteropathogenic Escherichia coli were detected in seven birds. Geese eliminated 10(7) and swans 10(9) fecal coliforms per day. Results of in situ studies showed that large flocks of waterfowl can cause elevated fecal coliform densities in the water column. From the data obtained in this study, it is possible to predict the microbial impact of migratory waterfowl upon aquatic roosting sites.

Animals↗
PubMed2000

Hospital-acquired infections among chronic hemodialysis patients.

The epidemiological characteristics of nosocomial infections among patients requiring chronic hemodialysis, a high-risk and rapidly growing population, have not been fully elucidated. During a 30-month cohort study, rates of bloodstream infections (BSIs), urinary tract infections (UTIs), pneumonia, and diarrhea caused by Clostridium difficile and the distribution of pathogens among hospitalized chronic hemodialysis patients were compared with hospitalized patients not requiring chronic hemodialysis. To identify risk factors for developing a nosocomial infection among chronic hemodialysis patients, a matched case-control study was performed. A total of 1,557 nosocomial infections were detected during 1,317 of 68,361 admissions (2%). Of these, 47 nosocomial infections occurred in chronic hemodialysis patients during 31 of 578 admissions (5%). Nosocomial infections were significantly more frequent among the chronic hemodialysis group (9.1/1,000 patient-days) compared with the non-chronic hemodialysis group (3. 8/1,000 patient-days; relative risk [RR], 2.4; 95% confidence interval [CI], 1.8 to 3.2; P < 0.001). UTIs were the most common nosocomial infections among chronic hemodialysis patients, accounting for 47% of all infections in this population. UTIs were significantly more common among chronic hemodialysis patients (4.2/1, 000 patient-days) compared with non-chronic hemodialysis patients (0.7/1,000 patient-days; RR, 6.2; 95% CI, 3.8 to 9.5; P < 0.001). Among chronic hemodialysis patients, Candida spp and enterococci were the most common pathogens in contrast to coagulase-negative staphylococci and Staphylococcus aureus among patients not requiring hemodialysis. Using conditional logistic regression, a greater index of comorbidity was significantly associated with nosocomial infections among the chronic hemodialysis population (odds ratio, 3. 6; 95% CI, 1.2 to 10.7; P = 0.02). Chronic hemodialysis patients are at a substantially greater risk for developing a nosocomial infection compared with other hospitalized patients.

Bacteremia↗
PubMed1987

LY146032: activity and resistance development in vitro.

LY146032, a new lipopeptide antibiotic, was compared with vancomycin, teicoplanin, cefamandole and ciprofloxacin, against 107 clinical isolates comprising methicillin-susceptible and methicillin-resistant Staphylococcus spp., Streptococcus faecalis and Corynebacterium spp. All staphylococci were susceptible to all agents, except that some of the methicillin-resistant strains were resistant to cefamandole. Only LY146032 and ciprofloxacin were bactericidal to Str. faecalis. Development of resistance was studied by serial transfers of ten selected strains. A stable greater than or equal to eight-fold increase of the MIC over the breakpoint was found to develop to a variable extent against all agents tested. Simultaneous development of resistance to any of the other antibiotics was registered in 11/200 tests.

Anti-Bacterial Agents↗
PubMed1993

Effects of imipenem, cefotaxime and cotrimoxazole on aerobic microbial colonization of the digestive tract.

Superinfections originating from a digestive tract colonized by abnormally high concentrations of aerobic microorganisms as a result of impaired resistance to colonization (CR) may complicate antibiotic therapy. In this study, patients with a moderate to severe systemic infection were randomized to receive either cefotaxime (CTX, n = 10) or cotrimoxazole (CTR, n = 10), 2 antibiotic regimens presumed to spare CR; or imipenem/cilastine (I/C, n = 19). The effect on CR was measured indirectly by comparing the aerobic faecal flora before antibiotic treatment with that on day 8 of treatment. An increase in aerobic faecal flora denotes a disturbed CR, whereas a decrease means that the organism is sensitive to the effective faecal concentration of the antibiotic. Imipenem/cilastine-treated patients showed a significant increase in enterococci and Candida spp., while the number of aerobic Gram-negative rods remained constant. Cefotaxime-treated patients had evidence of an increase in enterococci, but not of Candida spp., and Escherichia coli numbers decreased significantly. In these patients the concentration of other Gram-negative aerobic rods showed a slight increase in 6 patients with a resistant Pseudomonas strain. Cotrimoxazole-treated patients showed a significant decrease in aerobic Gram-negative rods, a significant increase in Candida spp. and no change in enterococci. It is concluded that all 3 antimicrobial agents impair colonization resistance. Whether or not this is followed by overgrowth with resistant micro-organisms depends on the active faecal concentration of the antimicrobial agent and the MIC of the aerobic micro-organisms. The risk of overgrowth of the bowel with resistant Gram-negative bacilli appears to be smaller following cotrimoxazole than following cefotaxime or imipenem/cilastine.

Adult↗
PubMed1989

Comparative in-vitro activity of meropenem on clinical isolates from the United Kingdom.

MICs of meropenem were determined for a wide range of common bacteria of clinical importance. For Enterobacteriaceae, Aeromonas spp., Haemophilus influenzae, Branhamella catarrhalis, Neisseria gonorrhoeae, Gardnerella vaginalis, Campylobacter coli/jejuni, beta-haemolytic streptococci and anaerobes other than Clostridium difficile, MICs were almost always within the range 0.002-0.5 mg/l. The activity of meropenem for these organisms was always greater than that of imipenem and piperacillin, and was similar to that of ceftazidime and cefotaxime except that strains resistant to these latter, and to piperacillin, were usually sensitive to imipenem and meropenem. Meropenem was also active against most non-fermentative Gram-negative bacilli, with MICs in the range 0.12-4 mg/l but Pseudomonas (Xanthomonas) maltophilia was often resistant, as it was to all the other drugs tested. Staphylococci, Strreptococcus pneumoniae and other alpha-haemolytic streptococci were usually more sensitive to imipenem than to meropenem, but even methicillin-resistant staphylococci were sensitive to both drugs (MICs less than 4 mg/l). Enterococci were also less sensitive to meropenem than to imipenem, and Enterococcus faecium was invariably highly resistant to all the drugs tested except ciprofloxacin, which had marginal activity. Results for Ps. maltophilia and Haem. influenzae were affected by media used for sensitivity testing.

Bacteria↗
PubMed2003

In vitro and in vivo activities of novel 2-(thiazol-2-ylthio)-1beta-methylcarbapenems with potent activities against multiresistant gram-positive bacteria.

SM-197436, SM-232721, and SM-232724 are new 1beta-methylcarbapenems with a unique 4-substituted thiazol-2-ylthio moiety at the C-2 side chain. In agar dilution susceptibility testing these novel carbapenems were active against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE) with a MIC(90) of </=4 micro g/ml. Furthermore, SM-232724 showed strong bactericidal activity against MRSA, in contrast to linezolid, which was bacteriostatic up to four times the MIC. SM-232724 showed good therapeutic efficacy comparable to those of vancomycin and linezolid against systemic infections of MRSA in cyclophosphamide-treated mice. The MICs of SM-197436, SM-232721, and SM-232724 for streptococci, including penicillin-intermediate and penicillin-resistant Streptococcus pneumoniae strains, ranged from </=0.063 to 0.5 micro g/ml. These drugs were the most active beta-lactams tested against Enterococcus faecium, and the MIC(90) s for ampicillin-resistant E. faecium ranged between 8 and 16 micro g/ml, which were slightly higher than the value for linezolid. However, time-kill assays revealed the superior bactericidal activity of SM-232724 compared to those of quinupristin-dalfopristin and linezolid against an E. faecium strain with a 4-log reduction in CFU at four times the MIC after 24 h of exposure to antibiotics. In addition, SM-232724 significantly reduced the numbers of bacteria in a murine abscess model with the E. faecium strain: its efficacy was superior to that of linezolid, although the MICs (2 micro g/ml) of these two agents are the same. Among gram-negative bacteria, these three carbapenems were highly active against Haemophilus influenzae (including ampicillin-resistant strains), Moraxella catarrhalis, and Bacteroides fragilis, and showed antibacterial activity equivalent to that of imipenem for Escherichia coli, Klebsiella pneumoniae, and Proteus spp. Thus, these new carbapenems are promising candidates for agents to treat nosocomial bacterial infections by gram-positive and gram-negative bacteria, especially multiresistant gram-positive cocci, including MRSA and vancomycin-resistant enterococci.

Abscess↗
PubMed2000

Potential use of presumptive enterococci and staphylococci as indicators of sanitary condition in plants making hard Italian-type cheese.

Raw milk, pasteurized milk, unripened cheese (1 day old), and partially ripened cheese (3 months) from 42 milk lots at a plant making hard Italian-type cheese were analyzed for presumptive enterococci using kanamycin esculin azide agar pour plates. Fully ripened (> or =10 months) cheeses, derived from other milk lots, were also tested. Numbers of presumptive staphylococci (Baird-Parker agar [B-P]) were determined in the partially and fully ripened cheeses. Presumptive enterococci were ubiquitous in raw milk, usually at levels of 2.1 to 3.0 log CFU/ml. Enterococci were detected in 11 (26%) of 42 pasteurized milk samples. Enterococci and staphylococci were detected in 39 (93%) and 6 (14%) of unripened cheeses and in 33 (80%) and 4 (10%) of partially ripened cheeses, respectively. Only eight and five samples of enterococci-positive unripened and partially ripened cheese, respectively, were made from pasteurized milk in which presumptive enterococci were detected. Of 42 samples of fully ripened cheese, 35 (83%) and 8 (19%), respectively, contained presumptive enterococci and staphylococci. Results suggest either that low numbers of presumptive enterococci survive pasteurization and cheese ripening or that contamination of cheese by enterococci occurs after pasteurization. Biochemical testing confirmed 63% of presumptive enterococci isolates. None of the 20 presumptive staphylococci isolates produced colonies typical of Staphylococcus aureus on B-P agar; the isolates were identified as 1 Staphylococcus epidermidis, 1 Staphylococcus xylosus, 2 Staphylococcus saprophyticus, 1 Staphylococcus warneri, 5 Kocuria spp., and 10 unidentified gram-positive, catalase-positive cocci. Three staphylococci isolates decreased in numbers by more than 3.0 log CFU/ml in 9.9 ml of skim milk heated 30 min in a 62.8 degrees C water bath. This finding suggests that most presumptive staphylococci detected may have been prepasteurization contaminants. Unless specificity of the kanamycin esculin azide and B-P media is improved, use of presumptive enterococci and staphylococci as indicators of postpasteurization sanitation in plants making hard Italian-type cheese cannot be recommended.

Animals↗
PubMed1982

Comparison of recovery of organisms from blood cultures diluted 10% (volume/volume) and 20% (volume/volume).

We compared blood cultures that were diluted 1:5 (20%, vol/vol) and 1:10 (10%, vol/vol) and contained specimens from patients with suspected septicemia. Streptococcus pneumoniae was recovered significantly more frequently from blood cultures diluted 20%, whereas gram-negative bacilli, group D streptococci, Staphylococcus aureus, and Candida spp. were recovered significantly sooner and more frequently from blood cultures diluted 10%. Statistically significant differences in isolation rates, however, represented only a small number of patients for whom the positive cultures affected therapy. We conclude that as long as at least two separate sets of blood cultures are obtained per septic episode from each patient, a 1:5 to 1:10 blood/vented (aerobic) medium ratio provides acceptable results. Nevertheless, the results also demonstrate that blood cultures diluted 10% provided greater and faster yields than those provided by blood cultures diluted 20%.

Bacteriological Techniques↗